TECHNICAL MEMORANDUMS - Coconino County, Arizona

Community Development

Jay Christelman, Director

January 2018

Coconino County Community Development (CCCD) Environmental Quality Program

2500 N. Fort Valley Road Bldg. 1

Flagstaff, AZ 86001 Work: (928) 679-8772 Fax: (928) 679-8851

TECHNICAL MEMORANDUMS

SUPPLIMENTAL DOCUMENTS AND REFERENCES FOR THE Aquifer Protection Permit Program

COCONINO COUNTYARIZONA COMMUNITY DEVELOPMENT DEPARTMENT

TABLE OF CONTENTS Introduction ............................................................................................................................................... 1 Technical Memorandums .......................................................................................................................... 3

Technical Memo: 001.2 Substantially Impermeable Soils ......................................................... 3 Technical Memo: 002.3 Disinfection ......................................................................................... 5 Technical Memo: 003.2 Treatment Technologies in Series ....................................................... 7 Technical Memo: 004.4 Drip Irrigation ..................................................................................... 9 Technical Memo: 005.5 Shaded Drip Irrigation Trench ............................................................ 11 Technical Memo: 006.5 Gray Water .......................................................................................... 13 Technical Memo: 007.2 Cap Systems ........................................................................................ 17 Technical Memo: 008.1 Volume Calculations ........................................................................... 19 Technical Memo: 009.3 Orifice Shields ..................................................................................... 23 Technical Memo: 010.1 Peat Systems ........................................................................................ 25 Technical Memo: 011.8 Submittal Requirements ...................................................................... 26 Technical Memo: 012.2 Textile Systems ................................................................................... 31 Technical Memo: 013.2 Flood Plain and Drainage Requirements ............................................. 33 Technical Memo: 014.1 Soils Analysis ...................................................................................... 35 Technical Memo: 015.2 Design Flow, Two Bedroom Residense .............................................. 37 Technical Memo: 016.0 Stoneman Lake TMDL ........................................................................ 39 Technical Memo: 017.1 Alternative Design Request ................................................................. 41 Technical Memo: 018.1 Submittals to ADEQ ............................................................................ 44 Technical Memo: 019.0 Oak Creek TMDL Studies ................................................................... 46 Technical Memo: 020.1 Smart Trench With Vault .................................................................... 48

Smart Trench Float Assembly with Vault A312G ........................................................ 50 Smart Trench Float Assembly with Chamber Vault A312G ......................................... 52 Smart Trench Float Assembly for Drip Irrigation A312G ............................................ 54

Technical Memo: 021.4 Rock Correction Factor ........................................................................ 56 Technical Memo: 022.1 Property Line Setback ......................................................................... 58 Technical Memo: 023.3 Denial & Appeals Process ................................................................... 60 Technical Memo: 024.2 Fees ..................................................................................................... 62 Technical Memo: 025.3 System Design Qualifications ............................................................. 66 Technical Memo: 026.2 Evapotransiration Bed Design ............................................................. 68 Technical Memo: 027.1 Proprietary List .................................................................................... 73 Technical Memo: 028.0 Westwood Estates ............................................................................... 84 Technical Memo: 029.0 Recreational Vehicle (RV) wastes ....................................................... 88 Technical Memo: 030.0 Repars and REmodels .......................................................................... 90 Technical Memo: 031.0 Nitrogen Reduction .............................................................................. 92 Technical Memo: 032.0 Construction Inspection/Discharge Authorization ............................... 94 Technical Memo: 033.0 Setback from Disposal to Treatment System ...................................... 98 Technical Memo: 034.0 Hydraulic Analysis ............................................................................... 100

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INTRODUCTION

TO: Designers FROM: Coconino County Community Development DATE: January 1, 2018 RE: Technical Memorandums

Due to conflicting interpretations of the rule or areas of the rule that need more definition or procedural guidance, a system of Technical Memorandums has been developed. The Technical Memorandums are to communicate review staff interpretations, definitions or required procedures to designers. It is being distributed to assist designers in preparing a submittal that conforms to ADEQ rules and quicken the speed at which plans are reviewed and approved.

Technical Memorandums are not rule; they are simply clarification or examples of acceptable procedures to meet the rule. The Technical Memorandums are intended to be a supplement to the Aquifer Protection Permit Program 18 A.A.C. Title 9, Articles 1, 2 and 3 and are not intended to modify any rule or portion of the rule not specifically noted in the Rule Citations listed at the top of each memorandum. The designer is responsible to know the rules and to prepare a submittal that complies with the rules.

The Technical Memorandum process is intended to be dynamic, future memos will be developed and existing memos may be revised or rescinded. Input from state and local regulatory staff and designers regarding current Technical Memorandums is welcome. Comments regarding the Technical Memorandums should be directed to Coconino County Community Development, Environmental Quality Program. Comments regarding the rules should be directed to ADEQ staff.

The Technical Memorandums are available in pdf (Acrobat) files. The Acrobat Reader is available at no cost at www.acrobat.com.

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TECHNICAL MEMORANDUMS

TECHNICAL MEMO: 001.2 SUBSTANTIALLY IMPERMEABLE SOILS

ISSUE DATE: July 26, 2002. REVISION DATE: January 12, 2006 revision per 2005 APP) TOPIC: Acceptable SAR for substantially-impermeable soils RULE CITATION(S): R18-9-A310.D.2 Limiting Conditions

R18-9-A311.C Facility Selection R18-9-A312.D Soil Application Rate R18-9-A312.E Minimum Vertical Separation This Technical Memorandum defines a substantially impermeable layer as a soil horizon that may cause or contribute to the surfacing of wastewater. Typically this would include: soils with a soil absorption rate less than 0.2 gallons per square foot per day; any soil classified as B, C, D, E or F under A312.D.2.b; any percolation rate greater than 120 minutes per inch; impervious rock; a one of saturation that may limit downward percolation; or soil with more than 50% rock fragments.. A disposal field may discharge treated effluent into a substantially impermeable soil horizon if an A312G is provided with ample justification. A Soil Application Rate less than one provided in the A312 SAR Tables (Percolation Rate or Soil Characteristics) will be required with adequate evidence of the feasibility of the requested application rate. It is solely the applicants responsibility to provide adequate justification for the soil application rate. A disposal field may discharge below a substantially impermeable layer if a permeable soil horizon with ample depth to a limiting layer is available. It is solely the applicants responsibility to provide adequate justification regarding the depth to the limiting layer such as bedrock, aquifer, etc...

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TECHNICAL MEMO: 002.3 DISINFECTION

ISSUE DATE: January 12, 2004. REVISION DATE: June 22, 2004 TOPIC: Disinfection, Chlorination RULE CITATION(S): R18-9-A312.A.2 Good Design Judgment R18-9-A312.A.2 Appropriate Design Methods and Calculations R18-9-E320.D.1.b Disinfection Detention R18-9-E320.D.1.a Disinfectant Consumption R18-9-E320.C.1 Disinfection Fail-safe This memo was prepared to provide assistance in the design of a disinfection system using chlorine. It is assumed that the design effluent is nominally free of coliform bacteria (1 cfu / 100 ml, 95 percentile). A chlorine residual of 2.0 mg/l after a 15 or 30 minute detention will achieve the design treatment level. A chlorine dose of 20.0 mg/l is expected to be adequate for aerobically treated effluent (30 mg/l BOD, 30

mg/l TSS, 7 pH, and 50° F). Dosage must be adjusted up or down to cover changes in effluent quality as provided in E320.D.1.a. Changes in temperature and pH can impact the dosage required to maintain adequate disinfection. Due to the cold winter temperatures in Coconino County, designs should be based on wastewater temperatures of 50°F. For a single-family residence, a peaking factor of 4 will be used to convert design daily flow to peak flow. For example, this produces a peak flow of 1.25 gpm for a 3-bedroom residence (450 gpd) and 2.08 gpm for a 5-bedroom residence (750 gpd). Complete mixing of chlorine with treated effluent is required to achieve adequate disinfection. For small systems, excess dosage is normally used to achieve adequate mixing. Good design practice requires plug flow conditions for a proper detention time, this will likely require baffling. Detention volume may be calculated using the flow rate and detention time. Where baffling is not provided a minimum safety factor of 2.00 will be required. The chlorine contact volume cannot be part of pump chamber due to the potential for short-circuiting. When the pump is activated, it may draw effluent that has not been detained for the time required to achieve adequate disinfection. A separate volume in the pump tank where the pump is separated from the chlorine contact volume by a baffle may be adequate. The pump chamber might be used for detention if a timer operates the effluent pump. Influent to the pump chamber must also be timer control. The timers must be set so that under all operating conditions the effluent in the pump chamber is detained for the minimum of 15 to 30 minutes (depending on wastewater temperature) prior to effluent pump operation. The required settings must be provided in the design report and installation instructions. The consumption of tablets must be calculated for the design daily flow rate.

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A fail-safe provision is required by rule, however the rule does not provide a definition of failsafe. CCHD will accept operation and maintenance procedures requiring the homeowner to monitor chlorine tablet usage and replenish when necessary. The following documents were used as reference materials for the preparation of this technical memo in conjunction with the 2005 APP rule revisions:

• ADEQ, Engineering Bulletin 12, Minimum Requirements for the Design and Installation of Septic Tank systems and Alternative On-site Disposal Systems, 6/89 (Out of Print)

• ADHS, Engineering Bulletin 11, Minimum Requirements for Design, Submission of Plans and Specifications of Sewage Works, 7/78

• WEF Manual of Practice No. 8, ASCE Manual and Report on Engineering Practice No. 76, Design of Municipal Wastewater Treatment Plants, 1992

• US EPA, Onsite Wastewater Treatment Systems Manual, 2/02 Example 1:

• Design Flow: 450 gpd

• unbaffled detention chamber of 100 gallons not meeting plug flow conditions

• 50°F Effluent

Peak Flow = 450 * 4 / 24 / 60 = 1.25 gpm (gal. / day) * - / (hr. / day) / (min. / hr.) = gal. / min.

Detention = 100 gal. / 1.25 gal./min. / 2 = 40 min >= 30.00 min. OK (gal.) / (gal. / min.) = min.

Example 2:


• Baffled detention chamber of 50 gallons meeting plug flow conditions

• 50°F Effluent

Peak Flow = 450 * 4 / 24 / 60 = 1.25 gpm (gal. / day) * - / (hr. / day) / (min. / hr.) = gal./min

Detention = 50 gal. / 1.25 gal./min. = 40 min >= 30.00 min. OK (gal.) / (gal. / min.) = min.

Example 3:


• Dosage: 20 mg/l (ppm)

• Tablet Weight: 140 gm per tablet

• % Chlorine: 70%

Chlorine Demand = [ 450 * (62.4 / 7.481 ) * 20 / (1,000,000) ] / 2.2 * 1,000 = 34.12 gm/day [ (gal. / day) * ( [lb./c.f.] / [gal./c.f.]) * - / (kg / lb.) * (gm / kg) = gm / day

Tablet Usage = 34.12 gm/day / (140 gm/tablet * 0.70) = 0.35 tablets/day (gm / day) / ([gm / tablet] * - ) = tablets/day

= 2.87 days/tablet

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TECHNICAL MEMO: 003.2 TREATMENT TECHNOLOGIES IN SERIES

ISSUE DATE: July 23, 2002. REVISION DATE: January 10, 2003 TOPIC: Reduction in TSS, BOD and Total Coliform Colony Forming Units based

on “stacking” technologies. RULE CITATION(S): R18-9-A312.D.3 Soil Absorption Rate

R18-9-A312.E.2 Minimum Vertical Separation When treatment technologies that reduce the TSS, BOD and Total Coliform Colony Forming Units are used in combination or “stacked” an additive reduction in pollutants is not practical. An acceptable approach to quantify a reduction is to use the first technology and a percent reduction for the subsequent technology. The rule recognizes each process type as having a certain percent reduction in BOD, TSS and Total Coliform. The reduction for TSS, BOD and Total Coliform is based on the difference in discharged pollution from a conventional system (septic tank with gravity leach trenches) and the advanced treatment system. This technical memorandum does not alter or reduce media loading rates. For example, if an ATU and a Wisconsin Mound are “stacked” or placed in series the full reduction of the ATU would decrease the TSS, BOD and Total Coliform Colony Forming Units per table 1.

TABLE 1

ATU

TSS 30

BOD 30

Total Coliform Log10 5.5

The percent reduction of the pollutants by the subsequent treatment is calculated based on the reduction that the treatment system would get compared to a septic tank. The percent reduction for a Wisconsin Mound is shown in Table 2. Please note the septic tank treatment performance is used only as a datum for the percent reduction calculation that the advanced treatment system is capable of achieving.

TABLE 2

Septic Tank Mound Reduction

TSS 75 30 60.0%

BOD 150 30 80.0%

Total Coliform Log10 8.0 Log10 5.5 Log10 2.5

Take the percent reduction you would get from the subsequent treatment and apply it to the effluent of the previous treatment process for the final effluent quality as shown in Table 3.

TABLE 3

ATU % Reduction due to Mound Final Performance

TSS 30 60.0% 12.0

BOD 30 80.0% 6.0

Total Coliform Log105.5 Log10 2.5 Log103

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An A312G will be necessary. Compliance with all Unified Water Quality Permit Rules is required.

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TECHNICAL MEMO: 004.4 DRIP IRRIGATION

ISSUE DATE: August 17, 2002 REVISION DATE: January 12, 2006 TOPIC: Subsurface Drip Irrigation RULE CITATION(S): R18-9-E322(D)(11) Soils

Drip irrigation is a practical approach to the distribution of effluent into any combination of soil texture and structure that is suitable for any pressurized distribution system. The rule was not intended to limit the use of drip irrigation to specific soils types. Coconino County will approve the use of drip irrigation into all permeable soils, without the need for an Alternative Design Request. For the purpose of this technical memo the definition of permeable soils is a soil that meets the requirements of the Sequence of Soil Characteristics Questions G through N per R18-9-A312(D)(2)(b) or a soil with a percolation rate below 120 mpi. The determination of soil permeability must meet the requirements of R18-9-A310. Compliance with all requirements of R18-9-E322 and other Arizona Statutes not specifically noted in the above Rule Citations is required.

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TECHNICAL MEMO: 005.5 SHADED DRIP IRRIGATION TRENCH

ISSUE DATE: August 2, 2002 REVISION DATE: October 29, 2007 TOPIC: Alterations and sizing calculations for the Shaded Drip Trench RULE CITATION(S): R18-9-E322.D.14.b R18-9-E322.D.14.d R18-9-E322.D.14.f R18-9-E322.D.15.a Installing drip irrigation lines per R18-9-E322.E.1 in areas with rocky soil can be difficult or impossible. The rule allows for an alternative means of installation using shaded drip irrigation trenches. Many installers have used a slightly differing approach to the shaded leach trench as outlined in rule. CCHD has been requiring Alternative Design Requests for those alterations. If the design of the shaded leach trench follows the rule or this technical memorandum an Alternative Design Request will not be required. The shaded leach trench must always be placed at 12 to 30” below natural grade when an appropriate amount of permeable soil is available for the placement within that depth window. In the event the shaded leach trench is installed at a depth less than 12” the size of the field and amount of drip irrigation line will be impacted by the requirements of sizing the field per R18-9-D.15.a. The following example outlines the differences in drip line requirements when a shaded leach trench is installed at a depth shallower than 12” or per the trench installation methods as outlined in R18-9-E322.E.1. Example:

• Design Flow: = 600 gpd

• Adjusted Soils Application Rate (See R18-9-A312.D.3) = 0.55 gpd/sf

• Drip Irrigation with 2’ between emitters and 2’ between drip lines.

• Drip line depth = 8” This first example assumes the drip system is installed per R18-9-E322.E.1. The minimum amount of drip line equals:

( ) ftseparationemitterft

ft

ftsfgpd

gpd

4922

984

98461.0

600

2

2

=−

=

This second example assumes the drip system is installed per R18-9-E322.D.15.a with a 24” wide shaded trench. The minimum amount of drip line equals:

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ftlfft

ft

lf

ft

ftsfgpd

gpd

29534.3

984

34.312

24

12

8

12

8

98461.0

600

2

2

=

=++

=

2 Lines per trench amounts to 590 feet of drip line. R18-9-E322.D.14.d requires the shaded leach trench to be backfilled with C-33 sand, decomposed granite or a combination of both. CCHD will allow the trench to be backfilled with cinder sand or native fill with a texture larger than clay. No rocks should come in contact with the drip line as they could puncture the line. R18-9-E322.D.14.f requires observation ports at both ends of all shaded trenches. CCHD will allow the installation of shaded trenches without the observation ports. Other than the above considerations, the design of the disposal field must follow the design and installation specifications as provided in the Unified Water Quality Permit Rules.

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TECHNICAL MEMO: 006.5 GRAY WATER

ISSUE DATE: September 20, 2002 REVISION DATE: January 12, 2006 TOPIC: Gray Water Systems RULE CITATION(S): R18-9-711 Type I Reclaimed Water General Permit for Gray Water

R18-9-701 Definitions R18-9-E303 4.03 General Permit: Composting Toilet

Questions have arisen concerning the generation and use of gray water when a composting toilet is used for human excrement. This Technical Memorandum has been developed to try to answer questions regarding gray water systems including their acceptability and use in Coconino County. R18-9-701.4 defines gray water as “wastewater collected separately from a sewage flow that originates

from a clothes washer, bathtub, shower and sink, but does not include wastewater from a kitchen sink,

dishwasher or toilet”. The following are the state rules regarding gray water use in Arizona for facilities generating no more than 400 gallons of gray water per day.

R18-9-711. Type 1 Reclaimed Water General Permit for Gray Water

A. A Type 1 Reclaimed Water General Permit allows private residential direct reuse of gray water for a

flow of less than 400 gallons per day if all the following conditions are met:

1. Human contact with gray water and soil irrigated by gray water is avoided;

2. Gray water originating from the residence is used and contained within the property

boundary for household gardening, composting, lawn watering, or landscape irrigation;

3. Surface application of gray water is not used for irrigation of food plants, except for citrus

and nut trees;

4. The gray water does not contain hazardous chemicals derived from activities such as

cleaning car parts, washing greasy or oily rags, or disposing of waste solutions from home

photo labs or similar hobbyist or home occupational activities;

5. The application of gray water is managed to minimize standing water on the surface;

6. The gray water system is constructed so that if blockage, plugging, or backup of the system

occurs, gray water can be directed into the sewage collection system or onsite wastewater

treatment and disposal system, as applicable. The gray water system may include a means of

filtration to reduce plugging and extend system lifetime;

7. Any gray water storage tank is covered to restrict access and to eliminate habitat for

mosquitoes or other vectors;

8. The gray water system is sited outside of a floodway;

9. The gray water system is operated to maintain a minimum vertical separation distance of at

least five feet from the point of gray water application to the top of the seasonally high

groundwater table;

10. For residences using an onsite wastewater treatment facility for black water treatment and

disposal, the use of a gray water system does not change the design, capacity, or reserve area

requirements for the onsite wastewater treatment facility at the residence, and ensures that the

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facility can handle the combined black water and gray water flow if the gray water system fails

or is not fully used;

11. Any pressure piping used in a gray water system that may be susceptible to cross connection

with a potable water system clearly indicates that the piping does not carry potable water;

12. Gray water applied by surface irrigation does not contain water used to wash diapers or

similarly soiled or infectious garments unless the gray water is disinfected before irrigation;

and

13. Surface irrigation by gray water is only by flood or drip irrigation.

B. Prohibitions. The following are prohibited:

1. Gray water use for purposes other than irrigation, and

2. Spray irrigation.

C. Towns, cities, or counties may further limit the use of gray water described in this Section by rule or

ordinance.

FLUSH TOILETS: A gray water system may be used for both surface and subsurface irrigation for the gray water generated if the residence is plumbed to separate the black water and gray water flows. However, a fully functional treatment and disposal system must be designed in accordance with the Unified Water Quality Permits. Further guidance on Coconino Counties interpretation of the Type I Reclaimed Water General Permit for Gray Water rules follows:

• Gray water is generated from all fixtures in a residence except toilets and kitchen sink/dishwasher. Wastewater generated from the flush toilets and kitchen sink/dishwasher is considered black water and must be treated and disposed in a manner outlined in Title 18, Chapter 9, Article 3.

• An onsite wastewater system must be designed to treat and dispose of all wastewater generated by the residence (black water and gray water).

• The gray waster system must be designed to divert the gray water into the black water system in the event the gray water system becomes clogged or unusable.

• Spigots and hose bibs may be connected to the gray water system and used for surface irrigation. Spigots and hose bibs may not be connected to the black water system.

• If pressure pipe is used for gray water distribution, purple plastic or other permanently marked materials shall be used.

NON-DISCHARGING TOILET:

R18-9-E303.B.2 requires that a compost toilet may only receive human excrement if the manufacturer’s specifications also allow for the deposit of kitchen or other wastes into the toilet. CCHD believes has been written incorrectly and should allow for the composting toilet to accept human waste, but not kitchen sink waste unless the manufacturer’s specifications allow for it. Therefore, CCHD will allow compost toilets to accept human excrement only, without the need for the toilet to be able to accept kitchen wastes.

When non-discharging toilets are used, the water generated from a kitchen sink/dishwasher must still be treated and disposed of in an acceptable fashion. This water can be treated and disposed of by one of two methods.

1. The first method is to discharge the wastewater from the kitchen sink/dishwasher directly to a composter if such a practice is acceptable according to the manufacture’s recommendations.

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2. A second method is to pass the wastewater generated from a kitchen sink/dishwasher through an interceptor and into a disposal bed or trench per R18-9-E303.F

3. A third method is to design a treatment and disposal system that can treat and dispose of all

wastewater generated (both black and gray water). For either method, the gray water disposal system must function year round under all normal design conditions. The requirement to be able to direct gray water to a sewage collection system or onsite system is required. Therefore, per R18-9-711.6 the gray water system must be constructed so that in the event of a blockage the gray water will automatically be directed into an onsite wastewater treatment and disposal system that meets the requirements of the Unified Water Quality Permit Rules. Furthermore, per R18-9-711.10, the use of a gray water system does not change the design, capacity or reserve area requirements for the onsite wastewater treatment and disposal system. If there are severe site constraints that prevents a conventional septic tank and disposal field system or any other alternative provided by a general permit from being installed a sewage vault would be acceptable. The sewage vault must meet the general permit requirements as outlined in R18-9-E314.

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TECHNICAL MEMO: 007.2 CAP SYSTEMS

ISSUE DATE: August 19, 2002. REVISION DATE: January 12, 2006 TOPIC: CAP System RULE CITATION(S): R18-9-E302 General Permit: Disposal by Trench

R18-9-E317 General Permit Cap System R18-9-E312 Facility Design (Minimum Vertical Separation & Setbacks)

Rule Clarification 009 Technical Memorandum rescinded, Technical Memorandum incorporated into General Permit 4.17

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TECHNICAL MEMO: 008.1 VOLUME CALCULATIONS

ISSUE DATE: September 28, 2002 REVISION DATE: October 5, 2004 TOPIC: Volume Calculations RULE CITATION(S): R18-9-A312.A.2. Appropriate design judgment, method, and calculations Questions have arisen concerning the calculation of volumes particularly as they concern pump chambers and float settings. It would also apply to the use of a septic tank for multiple purposes including a combined septic/pump chamber or part of the reserve volume for a pumping system. There are various acceptable methodologies including graphical analysis by a CAD program. While hand calculations are possible the spreadsheets, which are economical and readily available, will simplify the repetitive calculations to solve for unknowns. Tanks come in a three basic shapes: cuboid (concrete tanks), cylinders with flat ends (pipe sections), and cylinders with round ends (fiberglass). There are some other shapes which have not, as yet, been submitted to CCHD. (If selected, the designer shall follow a similar procedure to calculate volumes.) BASIC GEOMETRIC SHAPES:

Formulas are presented according to the rules for a Microsoft Excel spreadsheet. The basic geometric shapes are calculated as follows: CUBOID: The volume calculation for a cuboid would be applicable to precast concrete tanks. It is straightforward and has not been a problem but is shown to be complete. (The mathematical definition of cuboid is not limited to a rectangular parallelepiped where all sides are equal.) V = a * b * c CYLINDER, UPRIGHT The volume calculation for a cylinder with flat ends, standing upright would be applicable to pipe sections that are often used for pumping chambers. The surface area of the water surface remains unchanged as the depth changes making the calculation simple. V = A * h V = π * r ^ 2 * h

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V = π * d ^ 2 * h / 4 CYLINDER, ON SIDE, FLAT END The volume calculation for a cylinder with flat ends, on its side would be applicable to fiberglass tanks that have flat or nearly flat ends. The surface area of the water surface changes as the depth changes making the calculation much more difficult. A section through the cylinder will create a circle with depth of water, h, in it. The water surface width is the chord length, s. Since the depth, h, and radius, r, is know the angle, α, can be calculated from the following formula: h = r * ( 1 - Cos ( α / 2)) α = 2 * ACos ( 1 - h / r ) The section area of the water, A, can then be calculated from the following formula: A = r ^ 2 * ( α - Sin α ) 2 (Angular units must be in radians for the formula to work.) The volume can then be calculated by multiplying the area calculated above by the length of the cylinder: V = A * l SPHERE The volume calculation for a sphere would be applicable to fiberglass tanks that have round ends. (That is, the designer may add the volumes from the sphere and flat end cylinder to get the volume in a fiberglass tank with a spherical end.) The volume of a full sphere may be calculated with the following formula: V = ( 4 / 3) * π * r ^ 3 The volume of a partially full sphere, that is a segment of a sphere, may be calculated with the following formula: V = π * h ^ 2 * ( r - h / 3) APPLICATION:

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The geometric information provided above is applied to tanks used in onsite wastewater applications as follows: CONCRETE TANKS: Concrete tanks can be modeled for the purpose of volume calculations as a cuboid. Since the length and width is known, the volume can be calculated for any particular depth. When the volume is known, such as the operating volume for the pump, the depth can be calculated. PIPE TANKS: Tanks can be made from PVC Pipe sections placed vertically with flat end covers. The surface area of the water is constant and easily calculated using the above formula. Using that area, the volume can be calculated for any particular depth. When the volume is known, such as the operating volume for the pump, the depth can be calculated. Fiberglass tanks are also placed vertically but often have rounded tops. Since the rounded top is usually a reserve volume the calculations can be completed as they are for PVC Pipe sections. The reserve volume then includes a one half hemisphere calculated using the formula above. FIBERGLASS TANKS: Fiberglass tanks can be modeled for the purpose of volume calculations as a cylinder with a flat or spherical ends. In reality, the tanks are not actually either. Even for a single manufacturer, the variation can be easily visible. The diameter, length and volume of the tank is specified by the manufacturer. (The volume may be the total volume or the volume when operating as a septic tank with a freeboard.) Using the diameter and volume, the length of the tank may be calculated for both models. The model that provides the length closest to the specified length should be used in the calculations. For a preliminary estimate, the volume for various depths can be calculated including the unit volume. A table can then be prepared to assist the designer. It can be included in the design report to support design calculations. The following table is an example:

EXAMPLE End Type: Flat Diameter: 5.00 feet 60.00 inches Length: 8.33 feet 99.96 inches Volume = 1,224 gallons

Depth Depth Volume Volume Chg. Volume Unit Volume

feet inches gallons gallons % gallons/inch

5.00 60.00 1,224

174 14.2% 14.52

4.00 48.00 1,049

283 23.1% 23.57

3.00 36.00 767

309 25.3% 25.79

2.00 24.00 457

283 23.1% 23.57

1.00 12.00 174

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174 14.2% 14.52

0.00 0.00 0

When the volume is known, such as the operating volume for the pump, the depth can be calculated using the appropriate unit volume in a table created for the tank used in the design. Where the total volume provided is more than 110% of the required total volume, the preliminary estimate should be accurate enough. Where the total volume provided is close to the required volume then final calculations shall be completed using the depths from the preliminary estimate. If the calculated volumes total to less than the total tank volume then the design is acceptable. CONCLUSION:

The calculation of volume must be accurate for the purpose. It does not have to be perfect. The calculations must be conservative and provide an answer suitable for the proposed uses. That means the minimum interior dimension should be used in calculations. That means that float levels should be calculated to the accuracy that a float level can be set at not the accuracy a computer can achieve. If this level of algebra, geometry and trigonometry is beyond a designer’s ability then that designer should not submit designs requiring this level of “knowledge and competence” to CCHD. According to ADEQ Rule Clarification 001, the failure to demonstrate this level of “knowledge and competence” will allow the submittal to be denied. (That is, guessing right, is not an option.) This Technical Memo is meant to be a short primer. For further information, a number of short “cheat sheets” are available at any school/university supply business. Further training in geometry and trigonometry is available from Coconino Community College. (Such training is not part of the CCHD mission. WFM and EHS are not an economic option for the designer.)

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TECHNICAL MEMO: 009.3 ORIFICE SHIELDS

ISSUE DATE: September 28, 2002 REVISION DATE: February 21, 2006 TOPIC: Orifice Shields RULE CITATION(S): R18-9-A312.A.2. Appropriate design judgment R18-9-E304.D.a.xi. Orifice Shields Technical Memorandum rescinded, Technical Memorandum incorporated into General Permit 4.04

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TECHNICAL MEMO: 010.1 PEAT SYSTEMS

ISSUE DATE: September 28, 2002 REVISION DATE: December 13, 2004 TOPIC: Peat Systems RULE CITATION(S): R18-9-E311.D.2.e. Wastewater Loading ADEQ has listed both the EcoFlow and the Puraflow Peat Biofilters in their Proprietary Treatment Products List per R18-9-A309.E. The listed performance departs from R18-9-E311.D.2.e. CCHD has the authority per the delegation agreement to approve systems at the performance rates listed in the Proprietary Treatment Products List. The Proprietary and Reviewed Products List is updated periodically and is posted on the ADEQ website at http://www.azdeq.gov/environ/water/permits/download/listpro.pdf. The Ecoflow Peat Biofilter has been recognized as having a loading rate of 11.3 gpd per sq. ft. Therefore a single Ecoflow ST(B)-500 may receive a maximum design flow of 420 gpd. A single Ecoflow ST(B)-650 may receive a maximum design flow of 600 gpd. The Puraflow Peat Biofilter has been recognized as having a loading rate of 5.2 gpd per sq. ft. Therefore a single Puraflow Peat Biofilter may receive a maximum design flow of 150 gpd.

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TECHNICAL MEMO: 011.8 SUBMITTAL REQUIREMENTS

ISSUE DATE: April 30, 2007 REVISION DATE: April 29, 2007 TOPIC: Submittal Requirements RULE CITATION(S): R18-9-A301.D.1.b

R18-9-A312.A.1 Sign Design Documents R18-9-A312.A.2 Appropriate Design Methods & Calculations

To make the review process more thorough, efficient and expedient the Unified Water Quality Permit Rules and the Coconino County Department of Health (CCHD) requires specific items and specific formats to be submitted when seeking Type 4 General Permit(s). The following are minimum submittal requirements. All documents must be securely bound together. The integrity of the binding must be maintained during normal use of the document. The entire document must be legible without the need to remove the binding device. Single unattached pages are unacceptable. Stapling in the top left hand corner is acceptable for documents that do not exceed ten pages. For documents that exceed ten pages, bind the entire left edge of the document with something other than a staple. All submitted materials including county forms must be legible. All county forms are available in Adobe Acrobat Form formats. They can be filled out electronically by using Adobe Acrobat Reader which is available free of charge at www.acrobat.com.

A. Initial Submittal – The initial submittal will contain the full submittal documentation required for a Provisional Verification per the Unified Water Quality Permit Rules and will initialize the licensing time frame clock.

1. Notice of Intent to Discharge: a. Each submittal must contain two copies of a completed Coconino County Notice of

Intent to Discharge (I suggest the designer or applicant keep a copy). This form is available in hard copy or electronic format from the EQ office.

b. The Notice of Intent to Discharge is used to request the specific General Permits, and is used by county staff to prepare the Provisional Verification of General Permit Conformance upon acceptance of the design documents. It also verifies the applicant is aware of their legal obligations regarding the ongoing upkeep of the treatment and disposal system. Therefore, the applicant must sign the Notice of Intent to Discharge unless a signed and notarized Power of Attorney has been submitted giving another individual signing authority for all documents relating to the wastewater treatment and disposal system. The Power of Attorney is available in hard copy or electronic format from the EQ office.

2. Construction plans: a. The cover sheet of the construction plans must include the “Approval CCHD” block

and must be signed by the applicant. The “Approval CCHD” block is available from Coconino County in AutoCAD DWG and DXF, and Acrobat PDF formats.

b. The cover sheet of the construction plans must include the following county concept statement:

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The County approves these plans for concept only. All liability resulting from errors

or omissions is the responsibility of the designer. The County does not verify or

guarantee the measurements, calculations, ownership or conclusions indicated by the

creator of these plans.

c. The designer is responsible to assure that all Right of Ways and Easements have been provided on the Site Plan. To verify this is done the following note must be included in the Site Notes:

All efforts were made by the designer to locate and identify all Right of Ways and

Easements and show them accurately on the plans.

d. The designer is responsible to assure the location of the system meets any setback,

building envelope or other requirements per Covenants, Codes and Restrictions (CC&R) or Home Owner Associations (HOA). To verify this is done the following note must be included in the Site Notes

Designer has verified that all setback, building envelope or other requirements of

CC&R’s or HOA’s (if any) are met

e. Four sets must be submitted. One set will be sent to the contract reviewer for review. If the plans are accepted, one set signed by county staff will be sent to the designer and one set will be sent to the applicant, EQ will retain the final set.

i. Two sets stamped PRELIMINARY may be submitted in place of the four final plans. If preliminary plans are submitted one set will be forwarded to the contract reviewers and one set will be filed at the EQ office. Prior to issuance of a Provisional Verification, four sets of final plans will need to be submitted. One set will be forwarded to the contract reviewer, one sent will remain on file at the EQ office, one set signed by county staff will be sent to the applicant and one set signed by county staff will be sent to the designer.

f. The construction plans must be signed by the designer regardless of registration. 3. Floor plans:

a. The floor plans should be included in the Design Report unless the size of the floor plans prohibits this.

i. In the event the floor plan cannot be placed in the design report, two copies are required and must include a plan view that clearly illustrate bedrooms and all water fixtures. Elevations and structural details are not required.

b. One set will be forwarded to the contract reviewers and one set will be filed at the EQ office.

4. Design reports (if separate from the construction plans). a. Two copies are required. One set will be forwarded to the contract reviewers and one

set will be filed at the EQ office. b. The Design Reports must include a cover page with appropriate parcel number and

when applicable the subdivision, lot and street address. They must also include a Table of Contents and numbered pages that correspond to the Table of Contents.

c. The Design Report must be signed by the designer regardless of registration. 5. Soils report

a. Refer to Technical Memorandum 0.014 Soils Analysis to assure adequate soils information has been acquired and submitted.

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6. Right of Entry a. One copy is required; the contract reviewer will not need copies of this document. The

Right of Entry must be signed, notarized and recorded to the property deed. i. A receipt from the County Recorders Office is acceptable until the actual

documents are received. 7. Operation and Maintenance Affidavit

a. One copy is required; the contract reviewer will not need copies of this document. The Operation and Maintenance Affidavit must be signed, notarized and recorded to the property deed.

i. A receipt from the County Recorders Office is acceptable until the actual documents are received.

8. Operation and Maintenance Manual. a. Two copies are required. One set will be forwarded to the contract reviewers and one

set will be filed at the EQ office. b. The operation and maintenance manual must include a cover page with appropriate

parcel number and when applicable the subdivision, lot and street address. They must also include a Table of Contents and numbered pages that correspond to the Table of Contents.

c. The Operation and Maintenance Manual must be signed by the designer regardless of registration.

9. Setback Waiver for Well a. This document will only be required if the wastewater or disposal system encroaches

on the 50’ property line setback in an area not served by a community water system. i. Two copies will be required. One set will be forwarded to the contract

reviewers and one set will be filed at the CCHD office. 10. R18-9-A312(G) Alternative Design Justification

a. This document will only be required if a designer or applicant wishes to receive approval for a feature of improved or alternative technology, design, setback, installation or operation that differs from the general permit requirements.

i. Two copies will be required. One set will be forwarded to the contract reviewer and one set will be filed at the CCHD office.

11. Additions to Notice of Intent to Discharge. a. Several of the General Permits require additional information (i.e. warranties), if there

are additional requirements, two copies must be submitted. The additional information must be bound in the O&M Manual, Design Report or bound with the NOI (no loose papers are acceptable.) The checklist has an area for designer comments. This area of the checklist should indicate where the additional information is located.

12. Checklist a. CCHD has developed a checklist being used by the contract reviewers. This checklist

is available in hard copy or electronically at the CCHD office. It is available in an electronic format via email from Justin Ramsey ([email protected]).

b. The checklist outlines specific requirements of the rule and is broken into sections that correspond to the rule.

c. All submittals must include applicable checklist sections. The entire checklist does not need to be completed and submitted. Required sections of the checklist include A301, A309B, A310, A312 and applicable Type 4 General Permits (E302 through E322).

13. Planning and Zoning Commercial Verification

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a. This document will be required for all commercial projects. The form should be filled out thoroughly by the designer or applicant and given to planning and zoning for signature along with the site plan.

b. The Planning and Zoning Commercial Verification Form is available from CCHD. i. Two copies will be required. One copy will be forwarded to the contract

reviewer and one copy will be filed at the CCHD office. 14. Planning and Zoning Verification of Multiple Structures

a. This document will be required any time more than one structure is proposed on a property even if the second structure contains no fixtures.

b. The designer or applicant must fill out the Planning and Zoning Approval Form and provide it to planning and zoning along with a site plan and request the planning and zoning department review the plans and sign the completed form. The General Description of the site plan must be very detailed and include dates and who the plans were prepared by.

c. The Planning and Zoning Verification of Multiple Structures Form is available from CCHD.

i. Two copies will be required. One copy will be forwarded to the contract reviewer and one copy will be filed at the CCHD office.

15. Building Department Bedroom Count a. This document will be required if there is a question about a room being counted as a

bedroom. Any room that meets the definition of a bedroom (R18-9—101.8) in a residential structure must either be counted as a bedroom in the design flow calculations or must get approval from the county building department that the room will not be considered a bedroom.

b. The designer or applicant must fill out the Building Department Bedroom Count Form and provide it to the building department along with a floor plan and request the building department review the plans and sign the completed form. The General Description of the floor plans must be very detailed and include dates and who the plans were prepared by.

c. The Building Department Bedroom Count Form is available from CCHD. i. Two copies will be required. One copy will be forwarded to the contract

reviewer and one copy will be filed at the CCHD office.

B. Re-submittals - If during the initial or subsequent reviews a Request for Additional Information is required the following documents will be required for the re-submittal.

1. All documents that were associated with the request including additional information or alterations must be fully resubmitted. For instance:

a. Construction Plans - if construction plans required modification, four full sets of revised construction plans marked as such must be submitted. CCHD will not accept single or partial sets, the entire set of plans must be provided. Each sheet that has been modified must include a revision date.

i. Redline changes to the construction plans at the CCHD are acceptable but they must conform with the following guidelines.

• If the alterations are minor (i.e. typographical errors), the designer may request from the reviewer that they accept redline changes. Acceptance of this request will be at the discretion of the reviewer. The reviewer will only approve redline changes if he feels they can easily be made and will not add unnecessary confusion or complication to the construction plans. The designer or applicant must receive written

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confirmation from the reviewer (emails are acceptable). The written confirmation must clearly state exactly what the reviewer will allow the designer to modify, this will aid in the review process.

• The designer must make the changes to all three sets of plans on file at the CCHD office. Under no circumstance will the reviewer or county staff make redline changes to the plans on behalf of the designer.

• The changes must be made with red ink.

• In the bottom right hand corner of each plan sheet that a redline change was made, the designer must state redline changes were made, include the date and a signature.

• After the changes have been made it is up to the designer to notify the reviewer by telephone or email (preferably email) that the changes have been made. The reviewer will review the changes at his next scheduled visit to the CCHD office. A special trip made solely to review the redline changes will not be made and should not be requested. CCHD staff may review the changes, however this is solely at the discretion of the staff. Due to this, it may be quicker to get approval by resubmitting four sets of plans with the changes made.

b. Design Report – if modifications to the design report are required a complete revised Design Report will be required including updated Table of Contents and page numbering. The cover page must include Revised MO/DA/YR.

c. Operation & Maintenance Manual – if modifications to the Operation & Maintenance Manual are required a complete revised Operation & Maintenance Manual will be required including updated Table of Contents and page numbering. The cover page must include Revised MO/DA/YR. A new-recorded O&M Affidavit will also be required.

d. Notice of Intent to Discharge – If the NOI requires any modification if must be re-signed and dated by the applicant.

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TECHNICAL MEMO: 012.2 TEXTILE SYSTEMS

ISSUE DATE: December 24, 2002 REVISION DATE: January 12, 2006 TOPIC: Textile Systems RULE CITATION(S): R18-9-E312.D.3.b. Programmable Timer / Filter Dosing R18-9-E312.A.2. Recirculation. R18-9-A312.A.2. Good Design Judgment / Appropriate Design Technical Memorandum rescinded, Issues resolved in 2005 rule revisions.

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TECHNICAL MEMO: 013.2 FLOOD PLAIN AND DRAINAGE REQUIREMENTS

DATE ISSUED: December 22, 2002. REVISION DATE: August 16, 2007 TOPIC: Flood Plain and Drainage Requirements RULE CITATION(S): R18-9-A312.C. Setbacks R18-9-A312.A.2. Good Design Judgment / Appropriate Design

The Unified Water Quality Permit Rules do not specify setback distances to floodplains or floodways or specific county flood plain administrator requirements. The rules do specify distances to perennial and intermittent streams as well as washes. This technical memorandum is to provide guidance when developing systems in flood prone areas or on properties dissected by existing drainages. Definitions:

• Ephemeral Stream – A stream that generally only has flow occurring during, and for short periods after storms. Ephemeral streams are generally not hydraulically attached to an underlying or adjacent water table.

• Floodplain – The normally dry land area adjoining lakes, reservoirs or streams that is inundated during flood events. For the purposes of this Technical Memo the 100-year floodplain will be used for the definition. The flood plain elevation shall be based on FEMA defined elevations. If the lake, reservoir or stream is not located in a FEMA studied area the elevation shall be based on one of the following analysis techniques:

• Coconino County Drainage Manual

• Flow carrying capacity of the channel.

• Floodway – The channel of a stream and any adjacent floodplain areas that must be kept free of encroachment in order for the 100-year flood to be carried without substantial increases in flood height. FEMA’s minimum standards allow an increase in flood height of 1.0 foot.

• Intermittent Stream – A stream that generally has flow occurring only during the wet season. Intermittent stream flow is attached hydraulically to an underlying or adjacent water table.

• Lake - A large body of water contained in a depression of the earth's surface, and supplied from the drainage of a more or less extended area.

• Perennial Stream – A stream with continuous flow.

• Reservoir - A natural or artificial lake used for the storage and regulation of water.

• Wash – An ephemeral stream with a drainage area greater than 5 acres. The setback distance from a drinking water intake (private or public) from a surface water source is 200 feet. All streams, lakes, reservoirs, springs or streamside saturated alluvium are considered surface waters. No wastewater treatment or disposal system can be constructed in the 100-year floodway due to the potential of hazardous or scouring velocities and potential changes caused by the system to the floodway elevation. Any treatment or disposal system constructed in the floodplain must be protected from the flood by use of berms or rip-rap to the corresponding flood elevation.

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The setback distance from a lake, reservoir, perennial stream or intermittent stream is 100 feet measured from the 10-year, 24-hour runoff elevation. The flood elevation must conform to FEMA designated elevations if applicable. If the lake, reservoir or stream is not located in a FEMA studied area the elevation shall be based on one of the following analysis techniques:

1. Coconino County Drainage Manual 2. Flow carrying capacity of the channel.

The setback distance from a wash or drainage easement with a drainage area greater than 20 acres is 50 feet measured from the nearest edge of the defined channel or easement boundary. The 50-foot setback may be reduced to 25 feet if natural or constructed erosion protection is provided and is approved by the Coconino County Public Works Department. Anytime a drainage (natural or manmade) is to be relocated or altered to make room for the wastewater treatment or disposal system or any other reason, the design of the new channel or channel alteration must be approved by the County Floodplain Administrator prior to the wastewater treatment and disposal plans being submitted and reviewed by the Coconino County Health Department. If it has been determined by ADEQ that any surface water body that does not meet its water quality criteria and a Total Maximum Daily Load (TMDL) study has been prepared the recommendations from the TMDL will supersede the Unified Water Quality Permit Rules if the TMDL limitations are more stringent. It is the designer’s responsibility to obtain pertinent TMDL’s and take appropriate action during the design and placement of the treatment and disposal system.

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TECHNICAL MEMO: 014.1 SOILS ANALYSIS

ISSUE DATE: February 11, 2003 REVISION DATE: January 12, 2006 REVISION DATE: NA TOPIC: Soils Analysis Requirements & Procedures RULE CITATION(S): R18-9-A301.D.1.a Verification of Permit Performance

R18-9-A310.D.1.i ASTM Subsurface Characterization R18-9-A310.D.3.b Applicability of Soil Characterization R18-9-A310.E.1 Test Hole Locations R18-9-A311.C Appropriate Facility Selection R18-9-A312.D.1 Disposal Field Sizing

An applicant seeking to install an on-site wastewater treatment facility shall select a facility that is appropriate for the site’s geographic location, setback limitations, slope, topography, soil classification, wastewater infiltration capability, and depth to seasonally high groundwater table or other limiting subsurface condition. To insure that this information is documented and that all limiting site conditions are identified, CCHD requires a site investigation that has been completed by a Coconino County employed Sanitarian. The procedures for requesting a site investigation are as follows:

1. Have test holes dug in the area of the proposed disposal system and reserve area. A minimum of two holes must be dug in the vicinity of the disposal system and one hole in the vicinity of the reserve area.

a. The test holes should be excavated to a minimum of one foot below an encountered limiting layer or to backhoe refusal.

b. All test holes must be safe for entry by county staff and must be sized to allow sampling and analysis of the in-situ soils. The test holes must be ramped with a slope no greater than 2:1 and must be a minimum of 30 inches wide.

c. A re-inspection fee may be charged for any additional site investigations due to improper site preparation.

2. Submit a completed Site Investigation Application along with a Property Locater Form and inform

CCHD when test holes have been prepared. 3. Allow up to five working days to perform the site investigation (weather permitting). Due to the

possibility of scheduling difficulties this time frame may need to be extended if you request to be on location at the time of inspection.

4. Allow the district inspector five working days to notify the applicant of the site investigation results

and of any further testing that may be required.

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5. If there are inconsistencies between the CCHD site investigation and the designer’s site investigation, those inconsistencies will have to be reconciled through consultation between the CCHD staff and the designer prior to facility selection and design. A design review will not be completed if a conflict in soils analysis exists.

6. After the designer and CCHD staff have come to an agreement on the soils and sites limiting

conditions the design of the system may proceed. When the design of an appropriate system has been completed the site and soils information must be included in the Design Report when submitted to EQ for Provisional Verification.

Additional Items:

1. Additional holes may be required if conclusive evidence of the soils types cannot be determined from the initial test holes. It is the applicants’ or applicant’s representatives responsibility that a sufficient number of holes are dug to adequately analyze the soils in the area of the disposal system. Initial evaluation of the test holes may indicate that further excavations are required. If there are not sufficient open holes during the initial county review, the county reviewer may request additional holes be opened, this may result in additional review fees.

2. The applicant is solely responsible that the design and operation of a system. It is the applicants responsibility to verify the design meets the requirements of the Unified Water Quality Permit Rules and does not pose a public health hazard or environmental nuisance. Therefore the applicant or applicant’s representative must design a system that will function properly within the site and soils constraints regardless of the counties analysis. If a designer chooses to perform a soils analysis per the ASTM standards outlined in R18-9-A310.D.1.i or a percolation test as outlined in R18-9-A310.F it may be of value to the facility selection and design process

i. The results from percolation tests may be used to verify a specific soils type and associated soil application rate if the outcome from the ASTM subsurface characterization is inconclusive.

ii. In the event both an ASTM soils analysis and percolation testing are performed, and the results indicate conflicting soil application rates (SAR) the most conservative SAR will be used for the design.

3. The soils information must include all soils work performed on the project site, including county soils documentation, third party soils documentation and any percolation test results. As mentioned above, CCHD must verify all soils findings; therefore all soils reports must contain an onsite inspection form prepared by CCHD Staff.

4. The plan reviewers will assume horizons vary between holes in a linear fashion.

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TECHNICAL MEMO: 015.2 DESIGN FLOW, TWO BEDROOM RESIDENSE

ISSUE DATE: February 23, 2003 REVISION DATE: May 29, 2003

TOPIC: Design Flow, Two Bedroom Residence RULE CITATION(S): R18-9-A309.B.3. Design Flow Rule Clarification 6.1 Technical Memorandum rescinded, Issues resolved in 2005 rule revisions.

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TECHNICAL MEMO: 016.0 STONEMAN LAKE TMDL

DATE ISSUED: April 12, 2003 REVISION DATE: NA

TOPIC: Stoneman Lake TMDL Study RULE CITATION(S): R18-9-A312.A.2. Good Design Judgement / Appropriate Design The purpose of this Technical Memo is to summarize / describe the regulatory effect of the Stoneman Lake Total Maximum Daily Load (TMDL) study on onsite wastewater systems. The TMDL process addresses pollution impacts on Surface Water Quality on a much broader basis than just onsite wastewater system design. This Technical Memo is limited to the issues associated with the design of onsite wastewater systems covered by the ADEQ / Coconino County Health Department delegation agreement. Specifically, the wastewater systems covered by the Type 4 General Aquifer Protection Permits. (The TMDL does address other aspects of pollution must still be addressed appropriately by the proper parties.) The study indicates that the nutrient loading from onsite wastewater systems does not have a significant impact on the water quality of Stoneman Lake. No specific limits on nutrients have been established for existing or new onsite wastewater systems. The study established a “bright line” which is based on a lake water level of 6730 and a 100 foot setback. (A designer may complete a more detailed topographical survey of a specific property to more precisely locate the applicable features. The modification of the “bright line” will require a submittal to ADEQ.) The study establishes design criteria for onsite wastewater systems inside and outside of the bright-line setback.

Outside of the “bright-line”:

Existing systems that have failed shall be repaired or replaced in accordance with the current applicable rules and procedures. New systems shall be designed, constructed and operated in accordance with current applicable rules and procedures. Inside of the “bright-line”:

An existing system that has failed shall be replaced with an alternative system (GP 4.03 to 4.22). Existing standard systems (GP 4.02) that have failed shall not be repaired. New systems shall be alternative systems (GP 4.03 to 4.22). These systems shall be designed, constructed and operated in accordance with current applicable rules.

Problems associated with failed / poorly performing existing onsite wastewater systems do have health and environmental impacts. Three tiers of remedial actions are defined but the application is not specified. Current requirements regarding failed systems will continue to be applicable to all existing onsite wastewater systems.

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The map in the study shows wells, springs and washes. These all have setbacks based upon current rule that must be adhered to. The designer may find this a helpful reference. It does not modify existing rule on setbacks. Compliance with the setback requirement for a lake is required. (A312.C: 100 feet from the 10 year, 24 hour rainfall event) This is not the same as the “bright-line” location. The provisions of A312G may be applicable.

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TECHNICAL MEMO: 017.1 ALTERNATIVE DESIGN REQUEST

ISSUE DATE: April 15, 2003 REVISION DATE: January 13, 2006 TOPIC: Alternative design request procedures and limitations CITATION(S): R18-9-A312.G Alternative Design, Installation or Operational Feature

Delegation Agreement No. 00-0031

Delegation No. 00-0031 authorizes Coconino County Health Department (CCHD) to approve an alternative feature of design, setback, installation or operation under A.A.C. R18-9-A312.G if it achieves equal or better performance compared with the requirement specified in rule, or if it addresses site or system conditions more satisfactorily than rule requirements. The complete delegation agreement can be downloaded and/or reviewed at http://www.adeq.state.az.us/environ/init/delegate.html. Any variations in a submitted design from the general permit requirements must be accompanied by an alternative design request. The request shall meet the minimum requirements of R18-9-A312.G and be made using the form provided by CCHD. The form must be completed and include: a description of the requested change; the citation of the rule being altered; justification of the requested change including all supporting documentation. If multiple changes are requested, each change must be on a separate form. All alternative design requests must be attached to the Notice of Intent to Discharge (NOI). Part 3.8 of the delegation agreement limits what alternative design requests CCHD may review. CCHD does not have the authority to review or approve any alternative design requests that:

a. Is not a technology specifically outlined under General Permits 4.02 through 4.22. b. Changes a listed performance criteria for treatment technologies or hydraulic loading rates for

treatment media established under General Permits 4.02 through 4.22. c. Changes soil Application Rates, based on percolation test results or soil types. d. Changes Adjusted Soil Application Rates, based on percolation test results or soil types and

treatment performance of BOD5 and TSS. e. Changes the Minimum Vertical Separation based on total coliform concentrations.

CCHD will determine if it has the authority to review the alternative design request. The applicant shall submit all requests to CCHD as follows:

2. Applicant shall submit all required submittal documents to CCHD including review fees and alternative design requests (See Tech Memo 011.2 Submittal Requirements).

3. If the alternative design request is not requesting an alteration as listed in Part 3.8 as shown above or will not require excessive review time, research or expertise, CCHD will review the NOI and alternative design request.

a. If CCHD determines the alternative design request may achieve equal or better performance compared with the requirement specified in rule, or addresses site or system conditions more satisfactorily than rule requirements and does not adversely affect other permittees or contribute to a violation of an Aquifer Water Quality Standard it will allow the alternative design request and continue with the review.

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b. Acceptance of the alternative design request does not guarantee the design itself will be issued a Provisional Verification as submitted.

c. If it is determined the alternative design request has not provided adequate justification, CCHD will request additional information prior to issuance of the PV or deny the application.

4. If EQ determines an alternative design request has been made that falls within categories a. or b. of Part 3.8 of the delegation agreement as listed above:

a. CCHD will inform the applicant in writing that CCHD does not have the authority to proceed with the review due to the alternative design request. The letter may provide recommendations on how the design could be altered to allow CCHD to complete the review and issue the PV.

b. If the applicant chooses not to alter the design: i. The applicant shall inform CCHD in writing that they no not wish to alter the

design and request the entire design, including the alternative design request, be reviewed by ADEQ.

ii. EQ will provide the applicant with a signed letter requesting ADEQ perform the review, the letter may make recommendations to ADEQ and all previous correspondence between CCHD and the applicant shall be forwarded to ADEQ.

iii. CCHD will keep two sets of submittal documents and return remaining copies to the applicant.

iv. CCHD will refund to the applicant any unexpended fees. v. The applicant shall make the required submittal to ADEQ including ADEQ

review fees. 5. If CCHD determines an alternative design request has been made that falls within categories c.,

d. or e. of Part 3.8 of the delegation agreement as listed above: a. CCHD shall notify the applicant under the Administrative Completeness Review

procedure that the application is deficient because CCHD does not have the authority to proceed with the review due to the alternative design request and ADEQ does not review alternative design requests that fall within those three categories.

6. If CCHD determines an alternative design request would require excessive review time, research or specialized expertise:

a. CCHD will inform the applicant in writing that CCHD will not proceed with the review due to the alternative design request and associated review time, research or necessary specialized expertise. The letter may provide recommendations on how the design could be altered to allow CCHD to complete the review and issue the PV.

b. If the applicant chooses not to alter the design: i. The applicant shall inform CCHD in writing that they no not wish to alter the

design and request the entire design, including the alternative design request, be reviewed by ADEQ.

ii. CCHD will provide the applicant with a signed letter requesting ADEQ perform the review, the letter may make recommendations to ADEQ and all previous correspondence between CCHD and the applicant shall be forwarded to ADEQ.

iii. CCHD will keep two sets of submittal documents and return remaining copies to the applicant.

iv. CCHD will refund to the applicant any unexpended fees. v. The applicant shall make the required submittal to ADEQ including ADEQ

review fees.

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TECHNICAL MEMO: 018.1 SUBMITTALS TO ADEQ

ISSUE DATE: April 15, 2003 REVISION DATE: January 13, 2006 TOPIC: Submittals to ADEQ CITATION(S): Delegation Agreement No. 00-0031

Delegation No. 00-0031 authorizes Coconino County Health Department (CCHD) to issue Construction Authorizations and Discharge Authorizations of General Permit for General Permits 4.02 through 4.23 being requested in Coconino County. The complete delegation agreement can be downloaded and/or reviewed at http://www.adeq.state.az.us/environ/init/delegate.html. All applicants applying for Construction Authorizations or Discharge Authorizations in Coconino County must submit the Notice of Intent to Discharge (NOI) and accompanying information to CCHD per the submittal requirements outlined in Technical Memorandum 011 Submittal Requirements. The Arizona Department of Environmental Quality (ADEQ) will not review a NOI for a General Permit 4.02 through 4.23 being requested in Coconino County unless it is accompanied by a written request from CCHD (refer to Technical Memorandum 017 for CCHD review limitations).

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TECHNICAL MEMO: 019.0 OAK CREEK TMDL STUDIES

DATE ISSUED: May 5, 2003 REVISION DATE: NA

TOPIC: Oak Creek TMDL Studies RULE CITATION(S): R18-9-A312.A.2. Good Design Judgement / Appropriate Design R18-11-112.H.2. Oak Creek Water Quality Standards. R18-11-107.D. Antidegradation The purpose of this Technical Memo is to summarize / describe the regulatory effect of the Total Maximum Daily Load (TMDL) studies in Oak Creek on onsite wastewater systems.

• “Total Maximum Daily Loads (TMDLs) for Total Phosphorus and Total Nitrogen in the Oak Creek Basin, Arizona (Including Munds Creek)”, dated June, 1999

• Pathogen TMDL, Slide Rock State Park, Oak Creek Canyon, AZ”, undated, circa 1999 The TMDL process addresses pollution impacts on Surface Water Quality on a much broader basis than just onsite wastewater system design. This Technical Memo is limited to the issues associated with the design of onsite wastewater systems covered by the ADEQ / Coconino County Health Department delegation agreement. Specifically, the wastewater systems covered by the Type 4 General Aquifer Protection Permits. (The TMDL studies do address other aspects of pollution must still be addressed appropriately by the proper parties.) (The TMDL studies use the term “septic” which has been interpreted as any of the onsite wastewater systems covered by the Type 4 General Aquifer Protection Permits of which the standard septic system, 4.02, is the most common.) (The pathogen study title indicates a discrete portion of Oak but it is applicable to the water shed.) TMDL Studies:

The study indicates that onsite system have little impact on nutrient loadings. One reason given in the report is the limited developable land in the water shed. There are no specific design limitations or conditions in the study itself. However it references two documents that will have design provisions and limitations:

• “Oak Creek Policy” by ADEQ, dated 1990.

• “Guidance Document for the Repair and Upgrade of Existing Onsite Wastewater Treatment Systems in Oak Creek Canyon” by ADEQ / Oak Creek Septic Initiative, dated 1999.

ADEQ staff have indicated that these documents are no longer enforceable. They were included in the report for historical reference. CCHD does have a copy of the Oak Creek Policy but not a copy of the “Guidance Document . . .”. ADEQ staff were unable to provide a current copy. The nutrient study refers to an ongoing “census” of onsite wastewater systems that is being performed by CCHD staff. The result of that census, if it differs from the assumptions in the study, might indicate a need to revise the study. That census has been completed and no modification of the TMDL study is required.

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The nutrient study also indicates that there is a 1982 Coconino County Ordinance that restricts new development. Commercial development is prohibited. Residential development is limited to 1 residence per developable acre. (The developable area is the parcel area less the floodway and areas with a slope in excess of 25%.) This does not directly impact the design of the wastewater systems that are the subject of this Technical Memo but is presented for information purposes. The nutrient study also refers to the “Unique Water Designation” of Oak Creek by ADEQ as per R18-11-111.E.2. Numerical Water Quality Standards are included in R18-11-112.H.2. The application of these requirements is further described in the document:

• Oak Creek “Unique Water” Guidance Document, Draft, dated May 31, 1995. ADEQ staff were unable to provide a final copy. ADEQ staff have indicated that it is not enforceable. The pathogen study has similar results to the nutrient study. There are no specific design limitations or conditions in the study itself. It references the same documents and Coconino County development ordinance. It refers to the ongoing “census” of onsite wastewater systems the same. It refers to the Unique Water designation and associated rules. The pathogen study does recommend further study of onsite wastewater systems in regard to hydraulic conductivity of the soil on page 22. No documentation of further study is currently available. The pathogen study refers to the “Oak Creek Septic Initiative” and recommend that the definition of “failure” be developed on page 29. The previously mentioned document, “Guidance Document for the Repair and Upgrade of Existing Onsite Wastewater Treatment Systems in Oak Creek Canyon”, is the only documentation of that reference and recommendation that is currently available. The pathogen study does recommend the development of a prioritized system of upgrades and Best Management Practices (BMP) on page 29. No documentation of those BMPs is currently available. Requirements:

Therefore submittals to CCHD are required to comply with the current requirements in rule applicable to any other onsite wastewater system. There are no additional conditions based upon the TMDL or referenced documents. The designer should note that all site specific conditions including setbacks, groundwater depths, and highly permeable soils must be addressed to prevent a violation of water quality standards. (R18-9-A312.E.1, A310.B.1.h.)

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TECHNICAL MEMO: 020.3 SMART TRENCH WITH VAULT

ISSUE DATE: May 31, 2003 REVISION DATE: October 16, 2008 TOPIC: Smart Trench Assemblies RULE CITATION(S): R18-9-A310(D)(2)(D) Vertical Separation Distance to condition

that will cause surfacing of wastewater

R18-9-A310(D)(3)(b) Vertical Separation Distance to condition that will contribute to a violation of an Aquifer Water Quality Standard

R18-9-A12(E)(3) Determination of Limiting Subsurface Condition R18-9-A12(G) Alternative design, installation or operational features. R18-9-E414 Sewage Vault

Often times in mountain regions of Northern Arizona, no signs of a high groundwater table or seasonally saturated soils are present. The areas do have shallow soils consisting of clays with low permeability over bedrock. In areas with this subsurface morphology, reducing contact with the harmful microorganisms is required to diminish the public health impacts in the event the soils in the disposal field become saturated do to the wastewater discharge, and the effluent surfaces. Do to the impermeable nature of the soils the effluent will not readily be conveyed to an aquifer or contribute to a violation of an Aquifer Water Quality Standard.

A method to overcome these limitations consists of a “Smart” Trench Float Assembly that will disable the discharge pump prior to the surfacing of effluent. The system is designed with the “Smart” Trench Float Assembly installed in the most remote and lowest trench in each disposal zone. All effluent is disposed of through subsurface infiltration although evaporation and transpiration by plants is expected. Precipitation is allowed to naturally runoff of the disposal site. The float switch will disable the pump whenever the water in the float assembly rises to within one-foot of the final grade to assure wastewater does not surface. This alleviates the public heath concerns regarding potential harmful microorganisms in the effluent. This approach reduces the public health risk more so than disinfecting the effluent because if keeps the effluent well below the surface and out of contact with people as well as domestic animals and wildlife and is maintenance free. In the event the pump is deactivated the system will become a vault and haul system until the saturated condition of the soils is alleviated. A General Permit 4.14, Sewage Vault is required and all requirements for that permit must be provided. The manufacturer of the control panel must provide a written statement that the addition of the “smart” float at the field will not affect the manufactures warranty. The Construction Plans must include notes that Coconino County Health Department shall inspect the Smart float system to assure proper operation.

Three variations of this “Smart” Trench Float Assembly methodology have been developed and installed in Coconino County: Smart Trench Float Assembly with Vault; Smart Trench Float Assembly with Chamber

Vault; Smart Trench Float Assembly with French Drain and Vault for Drip Irrigation. Each method requires an A312G justification to be included in the Notice of Intent to Discharge. Coconino County

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Environmental Quality has developed the required A312G reports with sufficient justification. An applicant wishing to use one of the three methods may simply reference the A312G justification attached to the end of this Technical Memorandum. If a variation of any of the provided methods is requested the applicant will be required to provide an A312G report with adequate justification.

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SMART TRENCH FLOAT ASSEMBLY WITH VAULT A312G

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SMART TRENCH FLOAT ASSEMBLY WITH CHAMBER VAULT A312G

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SMART TRENCH FLOAT ASSEMBLY FOR DRIP IRRIGATION A312G

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TECHNICAL MEMO: 021.4 ROCK CORRECTION FACTOR

ISSUE DATE: May 30, 2003 REVISION DATE: January 12, 2006 TOPIC: The reduction in Soil Application Rates due to a percentage of subsurface

rock. RULE CITATION(S): R18-9-A312.D Soil Application Rates

R18-9-A312.E Limiting Subsurface Conditions As effluent moves through soils, the soils provide additional treatment to the wastewater through mechanical filtration and biological contact with microorganisms. Rock limits the actual contact of the water with the soil particles thus reducing the treatment capabilities of the soils. The soil application rates have been developed assuming little to no rock. In areas where subsurface rock is prevalent, a methodology to compensate for the rock, a rock correction factor (rcf), has been developed by ADEQ. Per ASTM D5921 the percent rock is considered insignificant if there is less than 15% therefore, no rcf is required if there is less than 15% rock. If the rock correction factor is required, CCHD will reduce the rcf by 15% to minimize the disparity between a subsurface condition with 14% rock and 16% rock (see example below). The rcf shall be determined based on the adjusted soil application rate and percent of rock present in the absorption area. An initial soil application rate must be selected per R18-9-A310.D and R18-9-312.D and then adjusted per R18-9-312.D.3. The rcf is simply the adjusted soil application rate multiplied by the percent of soil in the absorption field. If rock is greater than 50%, it becomes the predominant and soil meets the Sequence of Soil Characteristics Questions for Soil Type A. Therefore, an A312G justification for discharge into that soil type is required (justification must include level of treatment; application rate; distribution; subsurface effluent transport into the environment).

Per ASTM D5921 and R18-9-A310.D the definition for rock for this technical memorandum is any particle greater than two mm.

EXAMPLE:

The site soil survey has determined that the absorption area consists of a sandy clay texture with moderate structure and contains 30% rock fragments. Per the Sequence of Soil Characteristics Questions the soil has an unadjusted application rate of 0.40 gpd/sf (assuming a shallow disposal field) with an adjusted soil application rate of 0.47 gpd/sf. The rock correction factor is calculated as follows:

100% - 30% (rock) + 15% (negligible amount) = 85 % 0.47 gpd/sf * 85% = 0.40 gpd/sf

The 0.40 gpd/sf shall be the final application rate used to size the disposal field.

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TECHNICAL MEMO: 022.1 PROPERTY LINE SETBACK

ISSUE DATE: July 14, 2003 REVISION DATE: January 12, 2006 TOPIC: 50’ setback to property lines. RULE CITATION(S): R18-9-A312.C Setbacks R12-15-818 Well Location The setback table under A312.C specifies the minimum setback is five feet for an OWTF relative to a property line when the adjacent property is served by a common drinking water system is 5 feet. A common drinking water system is defined by rule as a “system that currently serves or is under legal obligation to

serve the property”, this may include a drinking water utility, a well-sharing agreement or other viable water supply agreement. If an adjacent properties water system meets this definition the name of the water utility or a copy of the well sharing agreement or other water supply agreement must be provided to CCHD. The same setback table also allows the setback to be reduced to five feet if the adjacent property has an existing drinking water well. The location of existing wells must be shown on the Site Plan. It would be prudent for the designer and/or applicant to verify with the adjacent property owners that the existing wells are operational (not dry) and further potable well drilling is not planned on the property. The setback table under also allows the setback to be reduced from 50’ to a minimum of 5’ from the property line of adjacent property not currently served by a common drinking water system or existing well if the owners of the affected property agrees in writing to limit the location of any new well on their property to at least 100 feet from the proposed wastewater treatment and disposal system including reserve area. The arrangements and documentation must be approved by Coconino County Health Department (CCHD). An approved Setback Waiver is available from Coconino County. The Setback Waiver must be completely filled out then signed by the property owner of the affected property and notarized. The Setback Waiver must than be recorded at the county recorders office and submitted to CCHD. The Setback Waiver consists of two pages. The first page is the waiver for the owner of the adjacent property to permit the proposed wastewater treatment and disposal system including the reserve area to be located within 5’ of the property, by agreeing to limit the location of any future well to a minimum of 100’ from the proposed system. The second page is for the owner of the proposed system to reciprocate the agreement by allowing the adjacent property owner to place their future wastewater treatment and disposal system including the reserve area within in 5’ of the shared property line. This reciprocation is not a requirement of the rule, but this gesture of goodwill may aid in getting adjacent property owner to agree to the waiver and will allow both wastewater systems to be located in the same proximity.

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TECHNICAL MEMO: 023.3 DENIAL & APPEALS PROCESS

ISSUE DATE: November 6, 2003 REVISION DATE: September 4, 2006 TOPIC: Procedures for the issuance or denial of a Provisional Verification RULE CITATION(S): R18-9-A301.D.1.d – Construction Authorization Denial

A.R.S. §§49-104 & 107 – Authorization to regulate sewage collection, treatment and disposal. Coconino County Ordinance No. 2003-4 – Hearing Officer Delegation Agreement No. 00-0031

The Delegation Agreement between Coconino County Health Department (CCHD) and the Arizona Department of Environmental Quality (ADEQ) requires an appeals process for final decisions concerning Type 4 General Aquifer Protection Permits. ISSUANCE OR DENIAL OF PROVISIONAL VERIFICATION PROCEDURES: After review of a Notice of Intent to Discharge and associated design plans, specifications or other documents or inspections (per Technical Memorandum 011) of an onsite wastewater treatment and disposal system, CCHD may Issue a Construction Authorization if it is determined the treatment and disposal system will conform to the requested general permit(s). If CCHD determines based on its review of design plans, specifications or other documents or inspections the facility may not conform to the requirements of the requested general permit(s) due to deficiencies or a lack of information, CCHD shall make a written Request for Additional Information. If a Request for Additional Information is made the applicant is expected to respond in writing to the request within a reasonable time period, specified in the deficiency letter. If the applicant fails to respond to the letter, fails to adequately supply sufficient information or fails to correct the deficiencies, CCHD may deny the request to discharge and provide the applicant with a Notification of Denial. The Notification of Denial shall state the reason(s) for the denial with reference to the statute or rule on which the denial is based. Upon receipt of the denial the applicant may file a Notice of Appeal, in writing on a form provided by the Coconino County Health Officer or designee, of that decision within thirty (30) days to the Health Officer or designee. The Coconino County Health Officer is:

Barbara Worgess, M.P.H. Director

Coconino County Health Department 2625 N. King Street Flagstaff, AZ 86004

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The Health Officer or designee will refer the appeal to the Hearing Officer within ten (10) business days after receipt of the Notice of Appeal. The Hearing Officer shall schedule an administrative hearing on the appeal within ten (10) business days of the receipt of the Notice of Appeal. A Notice of Hearing shall be served to the applicant at least ten (10) business days prior to the hearing. The appeal shall be heard no later than 30 days after the Hearing Officer receives the Notice of Appeal. If the applicant wishes to try to settle this matter before the administrative hearing occurs, the applicant must request an informal settlement conference with the Health Officer or designee. Requesting an informal settlement conference does not change the administrative hearing date. An informal settlement hearing may be pursued without filing a Notice of Appeal, however, regardless of the outcome of the informal settlement conference the applicant must file the Notice of Appeal within 30 days of receipt of the Notification of Denial if they wish to have an administrative hearing. APPEAL PROCEDURES: The Health Officer or designee will provide forms initiating the appeal. The notice of appeal shall be completed by the appellant and shall state the grounds based upon the statute or rule for the basis of appeal.

The appellant may be represented by counsel at his/her expense. The appellant must notify the hearing Officer in writing at least ten (10) days prior to the hearing date of his/her choice to be represented by counsel.

CCHD may also elect to secure counsel. If CCHD does secure council, CCHD must notify the Hearing Officer and the appellant in writing at least ten (10) days prior to the hearing.

If the appellant fails to appear by the date and time specified in the notice of hearing, the Hearing Officer shall dismiss the appeal for failure to pursue the appeal.

Within five (5) days prior to the hearing, both parties shall produce for inspection by the opposing party prepared exhibits to be on file at the hearing office. Failure to comply with this provision may result, at the Hearing Officer’s discretion, in denial of the exhibits to be presented as evidence during the hearing. The Arizona Rules of Evidence shall not apply before the Hearing Officer. Any evidence offered may be admitted, subject to a determination by the Hearing Officer. Audio tape recordings of the hearing shall be made and kept on record at the Department of Health Services Office for a period of one (1) year. A record of the proceedings may be made by a court reporter, if requested, at the appellant’s expense. At the discretion of the Hearing Officer, a hearing may be continued for a period not exceeding sixty (60) days. The Hearing Officer shall notify both parties, in writing, of the new hearing date. The decision of the Hearing Officer may be appealed by either party by filing a complaint with the Coconino County Superior Court within thirty (30) days after the decision.

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TECHNICAL MEMO: 024.2 FEES

ISSUE DATE: February 25, 2004 REVISION DATE: November 15, 2004 TOPIC: Review fees and fees and procedures with changes in system plans RULE CITATION(S): R18-9-A301.A.4.e – Applicable Fees

R18-9-A301.A.4.c –Construction of Facilities Deficiencies R18-9-A301.D.2. – Post Construction Requirements R18-9-A301.D.2 – Construction Conformance

R18-9-A309.C.2 – Discharge Authorization Delegation Agreement No. 00-0031

General Permit(s) shall be issued to construct sewage treatment and disposal systems on properties where sewer is not available. This will require a review of the construction plans, design reports, operation and maintenance manuals and possibly pre and post construction inspections of the site and facility (see TM 011 for submittal requirements). After reviews are completed and all deficiencies have been resolved the county will issue a Construction Authorization based on the submitted and reviewed documents. Prior to the issuance of Final Verification the applicant must submit a signed Request to Verify General Permit Conformance in addition to as-built drawings, revised operation and maintenance manual, revised materials list and other pertinent documents. If the constructed facility does not conform with the design approved under the Provisional Verification additional review fees may be required. REVIEW FEES

FEE SERIVCE BOARD

APPROVED FEE

FEE SERIVCE

BOARD APPROVED

FEE

Conventional System Permit $400.00 Commercial Systems:

Basic Alternate Permit $635.00 Conventional < 1000 GPD $440.00

Alternate System Permit $900.00 Conventional > 1000 GPD $475.00

System Repair Permit $235.00 Basic Alternate < 1000 GPD $620.00

Tank Only Permit $235.00 Basic Alternate > 1000 GPD $655.00

Room Addition/Remodel Review

$250.00 Alternate < 1000 GPD $620.00

Conventional Redesign Review $110.00 Alternate > 1000 GPD $655.00

Basic Alternate Redesign Review

$240.00 On-Site Inspection $275.00

Alternate Redesign Review - $380.00 Additional Inspection $80.00

Transfer of Ownership - $50.00

Haulers $175.00

Septic File Search $20.00

Well Site Inspection $330.00

DEFINITIONS

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• Conventional System - Septic tank with disposal by trench, gravelless trench, bed, or chamber

technology. (4.02, 4.05)

• Basic Alternate System - Systems including composting toilet, engineered pad, cap, or sewage

vault. (4.03, 4.09, 4.14, 4.17)

• Alternate System - All remaining alternate systems.

• System Repair Permit: Repair of a failing or damaged wastewater system.

• Tank Only Permit: Replacement of an existing septic tank or sites that share a common disposal field, however, each house needs its own tank.

• Room Addition/Remodel Review: Review of plans to upgrade a system due to increased daily flow as a result of an addition to an existing residence or commercial development.

• Conventional Redesign Review: The review of plans that have been significantly changed from the original permit due to applicant request, or if an application has been denied, for septic tank with disposal by trench, gravelless trench, bed, or chamber technology. A significant change would include moving the disposal field to an uninvestigated area, a new design report and calculations, a different disposal technology or a different treatment technology.

• Basic Alternate Redesign Review: The review of plans that have been significantly changed from the original permit due to applicant request, or if an application has been denied, for systems including composting toilet, engineered pad or sewage vault. A significant change would include moving the disposal field to an uninvestigated area, a new design report and calculations, a different disposal technology or a different treatment technology.

• Alternate Redesign Review: The review of plans that have been significantly changed from the original permit due to applicant request, or if an application has been denied, for all remaining alternate systems. A significant change would include moving the disposal field to an uninvestigated area, a new design report and calculations, a different disposal technology or a different treatment technology.

• Commercial systems Permits:

• Conventional <1,000 GPD: Permit for a conventional system on a project with a flow less than 1,000 gallons per day.

• Conventional > 1,000 GPD: Permit for a conventional system on a project with a flow more than 1,000 gallons per day.

• Basic Alternate < 1,000 GPD: Permit for a basic alternate system on a project with a flow less than 1,000 gallons per day.

• Basic alternate > 1,000 GPD: Permit for a basic alternate system on a project with a flow more than 1,000 gallons per day.

• Alternate System < 1,000 GPD: Permit for an alternate system on a project with a flow less than 1,000 gallons per day.

• Alternate System > 1,000 GPD: Permit for an alternate system on a project with a flow more than 1,000 gallons per day.

• On-Site Inspection: A site inspection on test holes to determine if it qualifies for a standard or alternative system.

• Additional Inspection: Additional inspections on test holes or on the final system inspection due to faulty or incomplete work by installer or backhoe operator.

• Transfer of Ownership: Processing of documents related to the inspection of the wastewater system when a property ownership is transferred.

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• Haulers: Inspection and permitting of companies that provide trucks to haul sewage, garbage or water.

• Septic File Search: Review wastewater permit and site investigation records when requested by the property owner, a prospective buyer or a realtor.

• Well Site Inspection: Review wastewater permit records and perform a site visit when property owner is proposing to construct a well. Note: Required by the Arizona Dept. of Water Resources.

RE-SUBMITTALS The following criteria apply to re-submittals (response to a request for additional information), changes after the Provisional Verification either before or during construction, or changes on as-built drawings after construction is complete. “Red Line”

Red line changes are allowable for changes such as:

• Typographical errors

• A different tank that does not require changes in calculations

• Minor inconsistencies within the plans

• A change to similar equipment New Plans and/or Design Report

• New plans are required for changes such as: � A moved component (tank, treatment, set back features) � A moved disposal to an area with test holes

• A minor change of disposal configuration

• A significant number of minor changes (as above for red line)

• A significant number of equipment changes with documentation Design Change

• New plans and a Redesign Review fee (Conventional, $250; Basic Alternate, $350; Alternate, $500) are required for changes such as: � Disposal moved to an area that requires a new Site Investigation � Changes in the design report/calculations (i.e., design flow, pump operating point)

• A change of disposal or treatment technology (a single permit change – disinfection may be an exception to allow two permit changes)

• Inadequate or incomplete documentation New Design

• New plans and a new System Permit fee (Basic Alternate, $600; Alternate, $900) are required for changes such as:

� Change of disposal and treatment technology (multiple permit changes).

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TECHNICAL MEMO: 025.3 SYSTEM DESIGN QUALIFICATIONS

ISSUE DATE: November 4, 2004 REVISION DATE: April 29, 2007 TOPIC: When is an Arizona Registered Engineer required for the design of a

wastewater treatment system (under General Permits 4.02 through 4.22). RULE CITATION(S): R18-9-A312.A.2 General Design Requirements

Rule Clarification 001-General design requirements (system design qualifications) A.R.S. § 32-144(A)(3) & (6) – Exemptions and Limitations A.R.S. § 32-145(1) – Violations; classification A.R.S. § 32-1121(A)(5) & (6) – Persons not required to be licensed; R18-9-A309.C.2.g – Contractor Requirements.

Definitions:

• Bona fide employee - Any person working under the direct supervision of a registrant who receives direct wages from the registrant or receives contract compensation from the registrant.

• Contractor – Any person, firm, partnership, corporation, association or other organization or a combination of any of them, that, for compensations, undertakes to or offers to undertake to, purports to have the capacity to undertake to, submits a bid or responds to a request for qualification or a request for proposals for construction services to, does himself or by or through others or directly or indirectly supervises others to

o Construct, alter, repair, add to, subtract from, improve any building structure, project development or improvement or any part thereof.

o Connect such structure or improvements to utility service lines , metering devices and sewer line.

• Detached single family dwelling - A single family dwelling unit such as a house which is structurally and physically separate from all other family dwelling units. This does not mean any single family dwelling unit which is part of a multiple dwelling unit building such as a duplex, townhouse, apartment building, condominium or cooperative. The term also includes all subsidiary buildings, structures and improvements such as garage, storage areas or guest house.

• Engineer - A person who by reason of special knowledge of the mathematical and physical sciences and the principles and methods of engineering analysis and design, acquired by professional education and practical experience is qualified to practice engineering as attested by his or her registration as a professional engineer with the Arizona State Board of Technical Registration.

The location and design of conventional or alternative wastewater treatment facilities under General Permits 4.02 through 4.22 must rely on appropriate design methods and calculations. The Uniform Water Quality Permit Rules do not limit any persons from designing conventional or alternative wastewater treatment facilities, as long as the design meets the requirements of the rule. CCHD considers this requirement to be satisfied if, based on submissions to the reviewing agency, the pertinent factors related to utilization of site data; system selection, location, and sizing; plan depictions; calculations; and construction and operation feasibility are assessed and realized in a technically correct, logical and documented manner. Fulfillment of this requirement is through specific knowledge of the rule and relevant technical knowledge and skill

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that would be applied by others who successfully obtain Construction and Discharge Authorizations of General Permit Conformance under this program. However, Arizona Revised Statutes do require specific systems to be designed by an Arizona Registered Engineer. The design of a conventional or alternative wastewater treatment system costing more than $12,500 for a structure other than a detached single family dwelling must be completed by an Arizona Registered Engineer or a bona fide employee of an Arizona Registered Engineer. Furthermore, the 2005 rule allows the regulatory agency to required a licensed contractor to perform the installation of a conventional or alternative wastewater system. . A Person who designs a conventional or alternative wastewater treatment system for other than a detached single family dwelling that exceeds the $12,500 limit is considered to be practicing engineering. Practicing engineering without a license is a Class 2 Misdemeanor. On April 26th 2001 the Arizona State Board of Technical Registration (SBTR) issued the following Substantive Policy defining “cost”.

A.R.S. § 32-144(A)(6) states that a non-registrant may design a water or wastewater treatment plant, or

extensions, additions, modifications or revisions, or extensions to water distribution or collection systems,

if the total cost of such construction does not exceed twelve thousand five hundred dollars. The term at

issue has, in the past, been consistently interpreted by the Board to include the design and construction of

the system. The term does not include any fees, such as for permits or registration, nor costs for

maintenance. This term also has not been interpreted to include costs for purchase of lands. The term

simply includes costs for services normally performed by a designer and a contractor .

Based on discussions with the SBTR, the term “normally” in the last sentence of the above policy prohibits the allowance of volunteer or donated labor or materials to be subtracted from the value or normal cost of the finalized system. Therefore the use of volunteer labor, which will certainly reduce the cost to the applicant for the overall system, will have no bearing on compliance with § 32-144(A)(6). CCHD will review commercial systems prepared by a non-engineer, if the review indicates the design meets the requirements of the Unified Water Quality Permit Rules a permit will be issued. However, if CCHD believes the normal cost of the system would exceed the $12,500 limit, CCHD will file a complaint with the Arizona State Board of Technical Registration (SBTR). The complaint would be based on a non-registrant practicing engineering under Arizona Revised Statutes § 32-141(A) and 32-145(1). Before the final Discharge Authorization will be issued by CCHD for any system designed by a non-registrant, except for detached single family homes, the applicant must submit all invoices, receipts or other items documenting the final cost of the system

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TECHNICAL MEMO: 026.2 EVAPOTRANSIRATION BED DESIGN

DATE ISSUED: January 20, 2005 REVISION DATE: January 13, 2006

TOPIC: ET Bed Design RULE CITATION(S): R18-9-E307. 4.07 Lined Evapotranspiration Bed R18-9-E306. 4.06 Natural Seal Evapotranspiration Bed R18-9-A309.B.3. Design Flow ADEQ rules require the designer to provide water mass balance calculations with the Notice of Intent to Discharge. The water mass balance calculation must show that the system functions during the winter months. The average minimum temperature must be above 20° F. No more than 1/3 of the annual precipitation may fall in a 30-day period. This technical memo provides guidance to the designer on a method to meet those requirements. There are other methods, formats and presentations that will meet the requirements of rule and will be acceptable to CCHD. The water mass balance must show the monthly evaporation, precipitation, effluent loading for one year in suitable units. (Units must be carefully and consistently calculated and applied.) The source for that data must be provided along with a justification for any adjustment. Those values must then be used to calculate the depth of effluent in the ET Bed each month of the year. The ET Bed must dispose of all effluent every month of the year. The value for the average daily minimum temperature must be provided for each month in the year. The source for that data must be provided along with a justification for any adjustment. The value for the average daily maximum temperature should be provided for each month in the year. The ET bed is designed on a monthly basis therefore a monthly average flow is appropriate for design purposes. (All other systems, including the septic tank serving the ET Bed, are designed on a daily basis therefore the daily maximum flow is the appropriate design flow value.) ADHS Engineering Bulletin 11, “Minimum Requirements for Design, Submission of Plans and Specifications of Sewage Works” indicates a ratio of 2:1 between the maximum and average flow is appropriate. The designer must submit an A312G form for any adjustment of the design flow including the one proposed in this paragraph. The reduction for grey water, as a percentage, established in rule and technical memo may be applied to the monthly average flow calculated above. Refer to those documents for the values and conditions on their use. Attached is a sample calculation of the water mass balance. (The spreadsheet was prepared by Engineering and Environmental Consultants, Inc. for their internal use only. It is not available from CCHD. It is used solely to provide a sample output format.)

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EVAPOTRANSPIRATION BED DESIGN CALCULATIONS ET Bed Data: Length, at surface: 120.00 ft Width, at surface: 50.00 ft Depth of Sand: 3.00 ft Area, at surface = 6,000.00 sf Void Ratio in Sand: 0.30 : 1 Seepage Loss: 0.0000 gpd/sf = 0 gpd/acre Weather Data: Evaporation Level (Average, Minimum, or Maximum): Average Effluent Loading: Actual Number of Bedrooms: 3 Design Number of Bedrooms: 4 Daily Design Flow @ 150 gpd/bedroom = 600 gpd Daily Max. / Monthly Ave.: 2.00 Monthly Average Flow = 300 gpd Adjustment for Graywater: 1.00 ET Bed Design Flow = 300 gpd Effective Application Rate = 0.050 gpdpsf

Month

Evapor- ation (in)

Precipi- tation (in)

Seepage (in)

Effluent (in)

Liquid Change

(in)

Liquid Depth

(in)

Initial Estimate of Depth at End of December: 11.41 January 1.76 2.05 0.00 2.49 2.78 20.66 February 2.48 1.76 0.00 2.25 1.53 25.75 March 4.00 1.91 0.00 2.49 0.40 27.07 April 5.28 1.07 0.00 2.41 (1.80) 21.06 May 7.20 0.57 0.00 2.49 (4.14) 7.25 June 7.92 0.51 0.00 2.41 (5.00) 0.00 July 7.92 1.90 0.00 2.49 (3.53) 0.00 August 7.20 2.08 0.00 2.49 (2.63) 0.00 September 5.52 1.48 0.00 2.41 (1.63) 0.00 October 4.24 1.49 0.00 2.49 (0.26) 0.00 November 2.64 1.41 0.00 2.41 1.18 3.92 December 1.76 1.52 0.00 2.49 2.25 11.41 Annual 57.92 17.75 --- --- Minimum 0.00 Maximum 27.07 Initial Estimate of Depth at End of December within 1%? YES Maximum Depth does not exceed Basin Depth? YES NOTES: 1. Designer shall confirm compliance with the applicable requirements. This spread sheet is simply a 2. The ET Bed is assumed to have vertical sides for the purpose of this model. 3. Refer to the Weather Spreadsheet for details on evaporation, precipitation, and temperature including 4. "Liquid Depth" is the depth of liquid in the sand medium with the specified void ratio.

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BASIC WEATHER DATA: Location: Sedona

Month

Evaporation Precipitation

(in.)

Temperature

Average

(in.) Minimum

(in.) Maximum

(in.) Minimum

(°F) Maximum

(°F)

January 2.20 1.53 3.35 2.05 29.1 54.8 February 3.10 1.95 4.16 1.76 31.6 59.6 March 5.00 3.20 6.60 1.91 34.5 64.0 April 6.60 4.37 8.37 1.07 40.7 72.7 May 9.00 6.29 10.84 0.57 47.5 81.2 June 9.90 7.54 11.41 0.51 56.3 92.2 July 9.90 7.98 14.43 1.90 63.9 96.1 August 9.00 6.20 10.68 2.08 62.4 93.3 September 6.90 4.16 8.60 1.48 57.1 88.8 October 5.30 3.10 7.00 1.49 47.4 78.1 November 3.30 1.84 4.70 1.41 36.3 65.3 December 2.20 1.60 3.20 1.52 29.7 56.3 Annual 72.4 49.76 93.34 17.75 Minimum 29.1 54.8 Maximum 63.9 96.1 WEATHER INPUT DATA: Evaporation Adjustment: 0.800 Precipitation Adjustment: 1.000 Temperature Adjustment: 1.000 PROJECT WEATHER DATA:

Month

Evaporation Precipitation

(in.)

Temperature

Average

(in.) Minimum

(in.) Maximum

(in.) Minimum

(°F) Maximum

(°F)

January 1.76 1.22 2.68 2.05 29.1 54.8 February 2.48 1.56 3.33 1.76 31.6 59.6 March 4.00 2.56 5.28 1.91 34.5 64.0 April 5.28 3.50 6.69 1.07 40.7 72.7 May 7.20 5.03 8.67 0.57 47.5 81.2 June 7.92 6.03 9.13 0.51 56.3 92.2 July 7.92 6.38 11.55 1.90 63.9 96.1 August 7.20 4.96 8.55 2.08 62.4 93.3 September 5.52 3.33 6.88 1.48 57.1 88.8 October 4.24 2.48 5.60 1.49 47.4 78.1 November 2.64 1.48 3.76 1.41 36.3 65.3 December 1.76 1.28 2.56 1.52 29.7 56.3 Annual 57.92 39.81 74.67 17.75 Minimum 29.1 54.8 Maximum 29.7 56.3 WEATHER DATA NOTES: 1. Precipitation: Arizona Climate, 1985, U of A. 2. Temperature: Arizona Climate, 1985, U of A. 3. Evaporation: Cooperative Extension Service, U of A & USDA "Evaporation from Open Water Surfaces in Arizona", 1970. 4. Precipitation and Temperature Adjustment is used to match data location to project location. 5. Evaporation Adjustment is based on the state map for the data.

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Evaporation from Open Water Surfaces in Arizona

NOTES:

1. These figures were copied from ADEQ Engineering Bulletin 12, Minimum Requirements for the Design and Installation of Septic Tank Systems and Alternative On-site Disposal Systems", dated June 1989. This document is no longer a current regulatory document.

2. These figures were originally from "Evaporation from Open Water Surfaces in Arizona", Folder 159, by The Agricultural Experiment Station and the cooperative Extension Service, The University of Arizona, 1970.

3. They have been used as a conservative determination of Evapotranspiration from onsite wastewater systems. Other methods may be equally appropriate for design purposes.

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Evaporation Bed Application Criteria

NOTES:

1. This figure was copied from ADEQ Engineering Bulletin 12, Minimum Requirements for the Design and Installation of Septic Tank Systems and Alternative On-site Disposal Systems", dated June 1989. This document is no longer a current regulatory document.

2. It was used for sizing ET Beds from 1989 to 2001 and is provided for information purposes only. A water balance as required by current ADEQ rule will indicate that an ET Bed designed using this figure will fail at design loadings.

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TECHNICAL MEMO: 027.1 PROPRIETARY LIST

ISSUE DATE: March 19, 2005 REVISION DATE: January 13, 2006 TOPIC: List of Approved Proprietary Treatment Products RULE CITATION(S): R18-9-A309.E Delegation Agreement No. 00-0031

R18-9-A309.E. requires ADEQ to maintain a list of proprietary and other reviewed products that may be used for on-site wastewater treatment facilities that comply with the requirements of A.A.C. Title 18 Chapter 9, Article 3, for Type 4 General Aquifer Protection Permit 4.03 through 4.22 for on-site wastewater treatment facilities. The list includes appropriate information on the applicability, performance and limitations of each product including manufactured systems, subsystems, or components within the treatment works and disposal works of the products that significantly contribute to the treatment performance of the system or provide the means to overcome site limitations. The list does not include septic tanks. All septic tanks must meet the requirements of A.A.C. Title 18, Chapter 9, Section A314. Part 3.8 of the Coconino County’s delegation agreement with ADEQ does not allow CCHD to approve changes in the listed performance criteria for treatment technologies or hydraulic loading rates for treatment media established under General Permits 4.02 through 4.22. However, CCHD has the authority to approve systems at the performance or loading rates as listed in the ADEQ proprietary list. CCHD will approve all systems on the proprietary list at the performance values or loading rates listed if designed per the listing requirements. CCHD may require documentation assuring the system is designed per the requirements of the proprietary list (i.e. CCHD may require the NSF reporting documentation). Any submittal consisting of a system not found on the proprietary list must include proof of performance. Below is ADEQ’s current Proprietary Treatment Products List (this list has been issued as DRAFT, however ADEQ has given CCHD authority to approve systems based on this list): The list is subject to Notes 1, 2, 3, 4 and 5 found at the end of the list. The following proprietary treatment products are deemed to comply with the technology definition and treatment performance criteria specified in A.A.C. Title 18 Chapter 9, Article 3, for Type 4 General Aquifer Protection Permits for on-site wastewater treatment facilities for residential service.

The list is developed and maintained by ADEQ, not CCHD. Any comments or requests for additions or revised performance values should be made to ADEQ.

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Insert Page 1 of 9 of the 10/11/05 Proprietary List

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TECHNICAL MEMO: 028.0 WESTWOOD ESTATES

ISSUE DATE: September 22, 2005 REVISION DATE: NA TOPIC: Design of Wastewater Treatment Systems in Westwood Estates RULE CITATION(S): Type 4 General Permit under Title 18 Chapter 9 Existing Approval to Construct by ADEQ, Dated 7/18/96

Westwood Estates Subdivision is an existing 78 lot subdivision with a unique Wastewater Treatment and Disposal System Approval to Construct. The Arizona Department of Environmental Quality (ADEQ) issued the Approval to Construct in 1996. The subdivision is unique because the development includes a constructed wetlands which is now owned and operated by the Home Owners Association. The constructed wetland is used to tertiary treat and dispose of the wastewater generated by the residents in the subdivision. Individual lot owners are responsible to provide secondary treatment of their wastewater and pumping that wastewater into the headworks of the constructed wetland through public low pressure sewers. The permit specifically states “the sewage collection system [this is the low pressure sewers as discussed above] shall only

receive treated effluent from NSF Class I Home Aerobic Treatment Plants”. The system was originally designed for each residence to install a Hydro-Action G-500, 1,000 or 1,500 Aerobic Wastewater Treatment System followed by a pumping system consisting of a Grundfos Model 16S ½ HP pump. When Coconino County accepted the delegation agreement from ADEQ for the permitting of alternative wastewater system they developed a special permit fee of $635 and expedited review for the approval of treatment systems in Westwood Estates. This permit fee and expedited review assumed the design would be for the Hydro-Action System as described above, it also included an Operation and Maintenance Plan previously developed and on file with CCHD. Any deviation in the treatment, pump or O&M plan will require a full review fee of $900. It has been requested that other alternative technologies be allowed to be installed in the Westwood Estates Subdivision. Through correspondence with ADEQ, CCHD has been given authority to allow other technologies for Westwood Estates. Any treatment system approved for Westwood Estates must meet the following criteria:

a. is covered by a Type 4 General Permit under Title 18 Chapter 9; b. has treatment performance that is equal or superior to NSF Class 1; c. delivers effluent in an outfall pipe or other appropriate conveyance compatible with the approved low pressure

sewer line. Any system installed must meet all the requirements of the associated Type 4 General Permit including providing CCHD and the owner with an Operations and Maintenance Manual. To assure the low pressure sewer line is not overloaded a timing schedule was developed as part of the original design. The schedule will assure that all pumps do not operate at the same time. 24 hour timers must be installed on all pump chambers. The timers must only allow pump chamber discharge at scheduled times. The following table provides the allowable discharge times for each lot.

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Lot No.

Pumping Window Lot No.

Pumping Window

Lot No.

Pumping Window

1 12 AM - 4 AM 27 4 AM – 8 AM 54 12 PM – 4 PM

2 8 AM – 12 PM 28 12 AM - 4 AM 55 4 AM – 8 AM

3 4 AM – 8 AM 29 4 PM – 8 PM 56 12 PM – 4 PM

4 4 AM – 8 AM 30 12 PM – 4 PM 57 12 AM - 4 AM

5 8 AM – 12 PM 31 4 AM – 8 AM 58 4 PM – 8 PM

6 12 PM – 4 PM 32 12 AM - 4 AM 59 4 PM – 8 PM

7 8 PM – 12 AM 33 8 PM – 12 AM 60 4 AM – 8 AM

8 12 AM - 4 AM 34 4 PM – 8 PM 61 8 AM – 12 PM

9 4 AM – 8 AM 35 12 PM – 4 PM 62 4 PM – 8 PM

10 8 AM – 12 PM 36 8 AM – 12 PM 63 8 PM – 12 AM

11 12 PM – 4 PM 37 12 AM - 4 AM 64 4 AM – 8 AM

12 8 PM – 12 AM 38 8 PM – 12 AM 65 4 PM – 8 PM

13 12 AM - 4 AM 39 4 AM – 8 AM 66 8 AM – 12 PM

14 12 PM – 4 PM 40 8 AM – 12 PM 67 12 PM – 4 PM

15 8 PM – 12 AM 41 4 AM – 8 AM 68 12 AM - 4 AM

16 12 AM - 4 AM 42 12 AM - 4 AM 69 4 AM – 8 AM

17 8 AM – 12 PM 43 4 PM – 8 PM 70 4 PM – 8 PM

18 12 PM – 4 PM 44 12 AM - 4 AM 71 12 PM – 4 PM

19 8 PM – 12 AM 45 4 AM – 8 AM 72 8 AM – 12 PM

20 12 AM - 4 AM 46 8 AM – 12 PM 73 8 PM – 12 AM

21 4 AM – 8 AM 47 12 PM – 4 PM 74 8 AM – 12 PM

22 4 PM – 8 PM 48 8 PM – 12 AM 75 4 AM – 8 AM

23 8 PM – 12 AM 49 4 PM – 8 PM 76 4 PM – 8 PM

24 Wetlands 50 8 AM – 12 PM 77 12 PM – 4 PM

25 Wetlands 51 12 AM - 4 AM 78 8 AM – 12 PM

26 8 PM – 12 AM 52 8 PM – 12 AM 79 12 AM - 4 AM

53 4 PM – 8 PM 80 12 PM – 4 PM

The individual pump chambers must meet the requirements of R18-9-E304, including adequate storage capacity and surge protection. The pump must be a Grundfos Model 16S ½ HP pump or an approved equal pump with a matching pump curve. To assure an adequate surge capacity is provided, the volume in the pump chamber between the Pump On/Off Float switch and the Alarm On Float switch must be able to contain 20 hours worth of the average anticipated flow. The volume above the alarm must contain a minimum of 1 day’s storage at the design flow. An example has been provided below to demonstrate the requirements.

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Example:


• Average Daily Flows: 300 gpd (By definition, Design Flows incorporate a peaking factor, per ADEQ Engineering Bulletin No. 11, average daily flows are ½ maximum daily flows, and therefore the average daily flow can be considered ½ of the Design Flow).

• Assume a hypothetical tank as shown below.

Timer On/Redundant Off Float: The minimum water level for the Grundfos Model 16S ½ HP pump is 22”. The minimum water level over the pump may vary if a different pump is specified. The designer must provide the minimum water level if a pump other than the Gurndfos Model 16S ½ HP pump is specified.

Specifying a tether length of 3.5” and a 45° contact activation the float will close sending power to the timer and thus

allowing pump operation when the water level is 2.5” above the tether tie point. Redundant Off/Timer On Float:

Assuming a tether length of 3.5” and a 45° contact activation the float will close sending power to the timer and thus

allowing pump operation when the water level is 2.5” above the tether tie point. The designer must use the actual requirements from the equipment they specify. 3.5” * Sin 45° = 2.5 in The normally opened float will made contact with the water level rises to 2.5” above the tether tie point. Height to Normal Low Liquid Level: 300 gal (typ daily flow) = 300 gal *1 ft3/7.481 gal = 40 ft3/day 40 ft3/day/(9.6 ft * 4.5 ft) = 0.9 ft or 11 in 11 in + 2.5 in (from above) = 13.5 in Normal Low Liquid Level This is an arbitrary number but should be 4 to 6”. This will minimize the alarm triggering when the home uses average or slightly higher than average water usage. Required Surge Volume 300 g/d * 1d/24hr = 12.5 gal /hr 12.5 gallons / hr * 20 hrs = 250 gal (volume between Pump On/Off Float at Alarm On Float) 250 gal *1 ft3/7.481 gal = 33.4 ft3/day 33.4 ft3/day/(9.6 ft * 4.5 ft) = 0.8 ft or 9 in 9 in + 2.5 in (from above) = 11.5 in Alarm On Float: Assuming a tether length of 3.5” and a 45° contact activation the float will close sending power to the timer and thus

allowing pump operation when the water level is 2.5” above the tether tie point. The designer must use the actual requirements from the equipment they specify. 3.5” * Sin 45° = 2.5 in The normally opened float will made contact with the water level rises to 2.5” above the tether tie pont. Required Storage Volume:

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600 g/d (volume between Alarm On Float and the top of the pump chamber). 600 gal *1 ft3/7.481 gal = 80 ft3/day 80 ft3/day/(9.6 ft * 4.5 ft) = 1.9 ft or 22 in 22 in + 2.5 in (from above) = 19.5 in

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TECHNICAL MEMO: 029.0 RECREATIONAL VEHICLE (RV) WASTES


TOPIC: Recreational Vehicle (RV) Wastes RULE CITATION(S): R18-9-A309.B.3. Design Flow R18-9-A312.A.2. Good Design Judgment GENERAL: It has come to the attention of CCHD staff that some residences have allowed Recreational Vehicles (RV’s) to connect to their sewer service line and discharge waste into the onsite wastewater systems. Recently some requests to formally allow a connection point for an RV have been made. This Technical Memo was prepared in response. There is limited documentation available but failures have been identified including poor treatment performance and premature disposal system failure. Therefore some design guidance is appropriate. An RV generally has two containers one for toilet waste and one for other wastes including shower, lavatory, and “kitchen” sink. Some liquid and additives are added to the toilet generally before use is initiated. The purpose is to control odors and liquefy the waste. The toilet waste is different from the normal toilet waste for which the onsite wastewater system was designed. There is considerably less water but no reduction in organic load therefore the normal design values based upon liquid volume are not applicable to design. Some additives essentially slow the microbiological processes that consume the waste and thereby produce odors. These are the same microbiological processes that treat the waste in the various onsite wastewater systems therefore they are detrimental to the onsite wastewater system. Some additives are more environmentally “friendly” but there is some documentation that they increase the organic load. Chemical Toilets (i.e., camp or portable toilets) and Marine Toilets use the same basic principles. This memo is applicable to those devices also. MINIMUM DESIGN REQUIREMENTS The design shall address the provision of a connection to the onsite wastewater system for an RV. Specifically the designer shall address the need to protect the onsite wastewater system from the adverse impact of additives and provide adequate capacity to treat the organic loading from the RV. The RV shall discharge into a separate pretreatment tank. The pretreatment tank shall conform to the applicable requirements of a standard septic tank. It shall be sized to hold 3 times the volume of the RV’s waster holding tanks (black and grey water) with a minimum size of 200 gallons. The onsite system shall be sized for the organic loading from the RV in addition to the sizing determined by Rule for the residence per the normal design procedure using bedrooms and fixture units. (No reduction in treatment or disposal capacity

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for a lesser fluid volume is allowed.) A minimum of 1 additional bedroom (150 gpd) shall be added to the capacity of the onsite wastewater system, both the treatment and disposal components. OPERATION REQUIREMENTS A discharge to an onsite wastewater system that causes a violation of the requirements of ADEQ rule is prohibited. An RV, chemical toilet or marine toilet shall be operated in accordance with the recommendations of the manufacturer. The disposal of waste with additives shall conform to the recommendations of the additive manufacturer. The Installation, Operation and Maintenance Manual shall address the RV connection and pretreatment tank.

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TECHNICAL MEMO: 030.0 REPARS AND REMODELS


TOPIC: Repairs on Existing Systems and Remodeled Business’s or Residences RULE CITATION(S): R18-9-A309.A.7; 9 & 10

R18-9-A309.B.3. Design Flow Maintenance and Repairs

Many of the alternative wastewater systems operated include complex mechanical devises including pumps, blowers, control panels, valves and filters. These devises not only need routine maintenance to assure long term and proper operation, but they will occasionally need to be repaired and replaced. Permits, Notice of Intent to Discharge (NOI) or county approval for maintenance, repair or component replacement is not generally necessary. R18-9-A309.A.9 has a list of many items that are not considered routine maintenance which would require county involvement possibly including a NOI. Before any maintenance activity is undertaken the applicant or operator should review this list to assure the maintenance activity does not require a NOI. If there is any question regarding whether the maintenance activity is considered routine, the operator or applicant should verify that a permit is not required with county staff. Remodels

Wastewater treatment and disposal systems are installed and operated with an anticipated 20 year life expectancy. Over the operation life of the system the residence or commercial facility it is servicing may undergo a remodel. Any major remodeling activities will require approval from the Coconino County Community Development Department. Items that may require a redesign of the wastewater treatment and disposal facility include, but are not limited to, an increase in the design flow, a change in influent characteristics, an alteration to the wastewater treatment or disposal layout, or an encroachment on any applicable setbacks. In the event of a remodel the following steps must be undertaken:

1. Submit existing (if available) and proposed remodel plans to CCHD along with a Site Plan. 2. Complete a Remodel Application and submit with a $52.00 application fee. The form is available at

http://co.coconino.az.us/envsvc.aspx?id=705 or at the county health department at 2500 N. Fort Valley Road in Flagstaff.

3. CCHD will review the remodel and will either: a. Determine the remodel does not effect the existing permitted wastewater treatment and disposal system.

The remodel is then approved by CCHD. b. Determine the remodel will effect the system, CCHD will contact the applicant with new requirements:

i. Applicant will need the system expanded, replaced or a second system for the remodel will be required.

ii. Applicant will need to provide a new Notice of Intent to Discharge along with new plans, design report etc…

iii. Applicant will need to provide the applicable fee for the Notice of Intent to Discharge.

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TECHNICAL MEMO: 031.0 NITROGEN REDUCTION


TOPIC: Requirements for submitting a nitrogen reduction system RULE CITATION(S): R18-9-A317

R19-9-E315.C.6 The Arizona Department of Environmental Quality (ADEQ) has the authority to designate Nitrogen Management Areas. These areas are susceptible to nitrogen pollution and therefore require enhanced nitrogen treatment of decentralized wastewater treatment and disposal systems. Currently ADEQ has not designated any Nitrogen Management Areas in Coconino County. However they have required through the subdivision approval that all wastewater systems in the Majestic Views Subdivision be “denitrifying” systems. The term “denitrifying” is not defined in rule, therefore Coconino County Health Department has extrapolated a definition. Per E302.B.3 a standard septic tank with gravity disposal has an effluent nitrogen performance value of 53 mg/l total nitrogen. ADEQ has not listed Majestic View Estates as a Nitrogen Management Area, however it should be noted that for such areas the maximum total nitrogen concentration in the effluent is 15 mg/l. Based on these two ADEQ written performance requirements, CCHD believe a “denitrifying” system should fall somewhere between those two levels. A general permit E313 is for a Denitrifying System Using Separated Wastewater Streams, which lists a performance of 30 mg/l total nitrogen, CCHD will accept an effluent quality of 30 mg/l total nitrogen based on a 5 month arithmetic mean in any area which requires denitrification (other than areas listed as a Nitrogen Management Area). 30 mg/l falls between the two extremes listed above. The rule does specify a 5 month arithmetic mean but does not specify weekly or daily grab or composite samples, therefore CCHD will accept monthly as well as weekly or daily sample data that show an arithmetic mean of no more than 30 mg/l. To date the only system that has been submitted to CCHD as a denitrifying system is the Bio-Microbics MicroFAST system. Based on the information provided by Bio-Microbics, CCDH will accept the Bio-Microbics MicroFAST system as a denitrifying system which meets or exceeds an effluent quality of 30 mg/l based on a 5 month arithmetic mean. Designers may submit other aerobic treatment units for use in the Majestic Views Subdivision. The submittal must include relevant data showing the system meets the minimum nitrogen performance requirements. The submittal must also be based on an actual system design, CCHD does not have the means to review hypothetical designs.

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TECHNICAL MEMO: 032.0 CONSTRUCTION INSPECTION/DISCHARGE AUTHORIZATION

DATE ISSUED: November 28, 2006 REVISION DATE: NA

TOPIC: Requirements for Final Inspections & Discharge Authorization RULE CITATION(S): R18-9-A301.D.1.e & f

R18-9-a301.D.2 R18-9-A309.C R18-9-A314.3.d

CONSTRUCTION AUTHORIZATION

Prior to beginning construction of a wastewater treatment and disposal system under General Permits 4.02 through 4.23, an applicant must submit a Notice of Intent to Discharge to the Coconino County Health Department (CCHD) and receive a Construction Authorization (CA) from CCHD. See Technical Memorandum 011.8 for additional information on Submittal Requirements. Once the CA is issued the system must be constructed within two years. If CCHD does not receive the Request for Discharge Authorization and associated information within two-years of the CA, the CA the will expire and the applicant will be required to submit a new Notice of Intent to Discharge and the applicable fee to begin or continue construction. Once the applicant receives a CA the system can be constructed. The construction of the system must conform to the plans and documents approved by CCHD in the CA, and to any requirements stated in the CA. The contractor is required to read the CA and conform to all requirements listed. CCHD understands that minor alterations of the plans will likely be required during the construction phase, this is allowable, however all changes must be documented in as-built drawings. Minor changes to the configuration, dimension, depth, material or installation procedures do not require approval by CCHD as long as the change continues to conform to the items used as a basis for the original design. However, if there is a question regarding this, the contractor or applicant should contact CCHD for verification or approval of the changes. If CCHD determines that changes do not conform to the original design, the Discharge Authorization will not be provided. INSPECTIONS

CCHD is authorized under rule to inspect the facility during and/or after construction to determine that the construction conforms to the CA and that any changes are recorded in the as-built plans. If deficiencies in the construction are identified by CCHD, CCHD shall provide a written explanation of the deficiencies to the applicant. Because each type of treatment and disposal system requires varying inspection milestones it is impractical to list them in this document, the Construction Plans reviewed for the CA will outline the required inspections. A construction schedule for this system must be provided to, and approved by, the CCHD at least two weeks prior to the beginning of construction. The schedule must define milestone dates. The contractor is not required to meet the milestones exactly but alterations or delays must be provided to CCHD. CCHD may at their discretion inspect one or all of the milestones at the dates provided by the contractor. If the county does not inspect the milestones per the dates provided by the contractor, CCHD will not require the project to be delayed therefore the contractor can continue the construction of the system. However inspections by CCHD are essential for facilitating the final approval of this project, if CCHD is not provided with the ability to perform

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inspections, un-inspected system components and construction steps can be rejected and may require exposure, and/or replacement. SUBMITTAL REQUIREMENTS

A Discharge Authorization will not be issued until a Request for Discharge Authorization Form signed by the person responsible for assuring that installation of the facility conforms to the design approved under the CA is provided to CCHD, this is usually, but not necessarily, done by the designer of the treatment and disposal system. The following information must also be submitted along with the Request for Discharge Authorization:

Item No: ● As-built Plans 3 ● Final List of Equipment & Materials 3 ● Final Operation & Maintenance Manual 3 ● Copy of 1 year service contract 1 ● Name and license # of the Installation Contractor (if applicable) 1 ● Tank Certification 1 ● Water Tightness Certification 1 ● Contractor Home Owner Agreement 1 ● Other Documents per the CA 1

The as-built plans must show all changes to construction drawings approved under the CA. These drawings are very important and must accurately show what and where system components were installed. Many onsite wastewater system components are installed underground and without proper documentation if may be difficult to find components in the future in the event maintenance or replacement needs to be performed. The list of equipment and materials must be provided if any materials specified in the construction documents were substituted. This materials list is often included in the as-built drawings. A final Operations and Maintenance Manual will be required if materials specified in the Operations and Maintenance Manual have been substituted or if the original Operations and Maintenance Manual was not approved in the CA. The CA will state if a final Operations and Maintenance Manual was not approved in the CA. A service contract ensuring that the facility is operated and maintained to meet the performance and other requirements of the applicable general permits must be provided for a minimum of one year following the beginning of the operation of the wastewater treatment and disposal system. CCHD has the authority to require wastewater treatment and disposal systems approved under General Permits 4.03 through 4.23 to be installed by a contractor registered with the Registrar of Contractors. The CA will state if this is required. All tanks must meet the applicable requirements of R18-9-A314 and must come with a certificate from the manufacture verifying compliance with the applicable rules. If the plans approved for the CA specify leakage testing, a leakage testing certification must be provided by the individual who performed the leakage test. The Request for Discharge Authorization Form does have a certification area on the form that if filled out correctly meets this requirement.

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If any components in the construction documents approved by the CA are NSF compliant, the applicant must provide CCHD a signed copy of the Contractor/Home Owner Agreement to assure the NSF approved equipment is under the 2 year warranty. The CA may list other documents that will be required prior to issuance of the Discharge Authorization. The CA should be reviewed and if any documents are required they must be submitted at the time the Request for Discharge Authorization Form is submitted. DISCHARGE AUTHORIZAITON/DENIAL

Once CCHD is satisfied the construction conforms to the CA, CCHD will issue the Discharge Authorization. Upon receipt of the Discharge Authorization the applicant may use the facility per R18-9-A309.A.7. If CCHD determines that the construction does not conform to the CA and the applicant has not satisfactorily addressed the deficiencies, CCHD will deny the Discharge Authorization and the applicant will not have the authority to use the facility. CCHD will provide the applicant with the reason for the denial with reference to statute or rule on which the denial is based. The applicant does have the right to request an informal settlement conference and/or to appeal the denial. For more information on the informal settlement conference and appeals process please review Technical Memorandum 023.2 Denial & Appeals Process.

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TECHNICAL MEMO: 033.0 SETBACK FROM DISPOSAL TO TREATMENT SYSTEM

ISSUE DATE: April 29, 2007 REVISION DATE: NA TOPIC: Necessary setbacks between the disposal system and the treatment system. RULE CITATION(S): R18-9-A312.C Setbacks R18-9-A312.A.2 Design Judgment The setback table under A312.C does not provide a required setback between the disposal system and the treatment system. However to assure the disposal system does not cause differential settling around the treatment system an area of undisturbed soil between the disposal and treatment system is required. There must also be adequate space between the treatment and disposal system to assure constructability of both items. CCHD will allow drip disposal systems to be installed within 4’ of the treatment system, however if the drip system is installed within 6’ of the treatment system the plans must specify in relevant notes that the contractor must provide a minimum of 24” of undisturbed soil between the drip line trenches and the treatment system. CCHD will allow any type of trench other than drip to be installed at to 2 times the effective depth of the trench or 5 feet, whichever is greater. Effective depth is defined as the depth between the point of discharge to the bottom of the trench. If the disposal system is installed within 6’ of the treatment system the plans must specify in relevant notes that the contractor must provide a minimum of 2 times the effective depth of undisturbed soil between the drip line trenches and the treatment system.

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TECHNICAL MEMO: 034.0 HYDRAULIC ANALYSIS

ISSUE DATE: October 29th, 2007 REVISION DATE: NA TOPIC: Minimum Vertical Separation Distances RULE CITATION(S): R18-9-A310.D.2.d Limiting Conditions R18-9-A312.D Soil Application Rate

R18-9-A312.E.2.B Hydraulic Analysis R18-9-A312.E.3.a.ii Hydraulic Analysis

Minimum Vertical Separation is based on the Total Coliform Concentration of the effluent. The designer is required to assure the effluent meets the minimum vertical separation as listed in rule and using a hydraulic analysis verifying there is adequate soils to conduct wastewater downward or laterally without surfacing. The rule does not specify the hydraulic analysis. There are multiple hydraulic models available to the designer. The designer has the ability to use any model that accurately models the subsurface effluent flow. This Technical Memorandum describes one method which will be acceptable to the Coconino County Health Department. Discharging directly into an impervious horizon is not allowable using the procedures outlined in this Technical Memorandum. This Technical Memorandum does require adequate soils that will allow downward and/or lateral effluent movement through a soil horizon. This Technical Memorandum does not provide the sole method for providing a hydraulic model, it does provide a method deemed justifiable to CCHD. Designers may use alternative models.

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HYDRAULIC WASTEWATER LOADING RATES TO SOIL

E.J. Tyler*

ABSTRACT

Onsite wastewater infiltration rate into soil depends on the nature of soil clogging and soil characteristics. The rate of transmission of the infiltrated water through the soil away from the infiltration surface when a vertical flow restriction is present depends on the characteristics of the soil, the depth of the permeable soil horizons and the slope. A single table is presented to estimate design infiltration loading and hydraulic linear loading rates for onsite wastewater treatment systems using soil. KEYWORDS: Septic systems, Wastewater infiltration, Wastewater loading, Soil water flow, Linear-loading rate.

INTRODUCTION

The rate wastewater infiltrates soil from wastewater infiltration systems is limited by logging layers and controlled by the nature of both the clogging layer and the soil (Bouma, 1975). Once in the soil, the added water must continue to move away from the infiltration surface. This flow is independent of the nature of the clogging layer and only dependent on the nature of the soil. Water moves away from the system following the water potential gradients. In soils with flow restrictions, water movement may become horizontal. Water movement away from the infiltration surface must be greater than the wastewater infiltration rate or the system will fail. There have been many estimates of wastewater infiltration rates into soil. Infiltration rates for domestic wastewaters from septic tanks assuming around 570 L d-1 per bedroom (150 gpd/bedroom) are most frequently reported. Values are based primarily on experience. Some reported septic effluent rates have been reviewed by Keys, et. al 1998. Suggested infiltration rates for domestic wastewaters with reduced biochemical oxygen demand (BOD) are less common (Siegrist, 1987 and Tyler and Converse, 1994). Hydraulic linear loading rate is the volume of wastewater that the soil surrounding a wastewater infiltration system can transmit far enough away from the infiltration surface such that it no longer influences the infiltration of additional wastewater. The concept of hydraulic linear loading rate was first introduced by Tyler and Converse (1984). Since that time, there has been little done to assign possible design values for hydraulic linear loading rate; however, limits have been put on infiltration width in an attempt to limit the hydraulic linear loading rate. __________________ *E. Jerry Tyler is Professor of Soil Science and Director of the Small Scale Waste Manage-ment Project, University of Wisconsin-Madison, 1525 Observatory Drive, Madison, WI 53706, [email protected] and President of Tyler & Associates, Inc. PO Box 72, Oregon, WI 53575, [email protected].

*In: K. Mancel (ed.) On-site wastewater treatment. Proc. of the 9th International Symposium on Individual and Small Community Sewage Systems. ASAE. St. Joseph, MI. P .80-86. Therefore, a procedure to estimate values for hydraulic linear loading rates based on soil characteristics is needed. Since wastewater infiltration rates are also based on soil characteristics the procedure should include wastewater infiltration rates and present the two design values together.

OBJECTIVES 1. Define wastewater infiltration into soil and water flow away from wastewater infiltration systems and 2. Present a procedure to estimate wastewater infiltration and hydraulic linear loading rates based on soil characteristics assuming a wastewater quality and volume.

WASTEWATER LOADING RATES Wastewater movement into and through the soil depends on the interaction of the wastewater with the soil to create a clogging layer and on the hydraulic properties of the soil. Each type of flow is defined separately and the limiting flow is used for design.

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Infiltration Loading Rates Wastewater infiltration or loading rates define the rate wastewater enters the soil. When applying septic tank effluent, a clogging layer forms at the infiltrative surface. Clogging layers impede water infiltration and reduce the loading applied to far below the maximum infiltration rate of unclogged soil. Bouma (1975) explained the basis of wastewater infiltration into clogged soil. Since the water that passes the clogging layer also percolates through the soil then:

( )

c

cOCSC

z

zHKQQ

++==

ψ

where Qc is the flow through the clogging layer, Qs is the wastewater flow through the soil, Kc is the hydraulic conductivity of the clogging layer, Ho is the wastewater ponding height above the infiltrative surface, 'P is the soil moisture potential in the soil just outside the clogging layer and Zc is the thickness of the clogging layer. Wastewater infiltration into soil is dependent on the character of both the clogging and soil. Since soil is a factor in infiltration rate through a clogging layer, wastewater-loading rates will vary from soil-to-soil with the same clogging. The differences in wastewater infiltration rates are related to soil characteristics defining pore sizes and pore size distribution. Texture, structure, and consistence each contribute information about soil pores. Also, the mineralogy of the clay fraction is important. Of the soil characteristics soil structure provides the most information. Therefore, commonly described soil characteristics can be used with knowledge of operating clogged systems to estimate design values for wastewater infiltration for different soils assuming standard domestic wastewater and design volumes of 570 L d-1 per bedroom (150 gpd/bedroom) or greater. A method for predicting loading rates for domestic septic tank effluent based on soil morphological descriptions was developed (Tyler et al., 1991). In the absence of soil clogging, or in the presence of weakly developed clogging, as is likely when applying wastewaters of reduced organic strength or BOD compared to septic tank effluent, infiltration rates are higher than for clogged soil. The increase in infiltration loading rate for reduced strength wastewater and low BOD wastewater is not uniform or linear and is much greater for soil with larger pores than for those with fine pores. Therefore, a single factor between loading rates for clogged and unclogged soils cannot be used. For example, sandy soil loading rates are much greater without clogging than for clogged soil while in clayey soils the loading rate difference is small. As with loading rates for clogged soil, loading rates for soil receiving wastewater of low organic strength are related to the pores and therefore the described soil morphology. A method for predicting loading rates for wastewaters of reduced organic strength wastewater based on soil morphological descriptions has been reported (Tyler and Converse, 1994).

Water Percolation and Hydraulic Linear Loading Rate Once wastewater has infiltrated the soil, it moves without the direct influence of the clogging layer or a non-clogged infiltration surface. Water will move from a zone of higher potential to one of lower. In regions of moderate precipitation and with normal wastewater applications, some water will move downward. In a free draining soil, the added wastewater is not a problem; however, many soils have horizons of slow permeability that restrict downward water movement. If the wastewater application rate along with the natural waters exceeds the permeability of these horizons, episaturation will develop. Dissipation of the episaturation is by vertical movement through the underlying slowly permeable horizons and horizontally downslope beneath the ground surface in the shallow soil horizons. If the water is not dissipated from the zone of episaturation as fast as water is added, the system eventually fails hydraulically. The maximum horizontal flow per unit length or hydraulic linear loading rate is dependent on the ability of the soil to transmit the water horizontally, the depth of soil for transmission and the slope of the induced surface of groundwater. It is assumed the depth available for transmission is above the restricting horizon and episaturation and below the infiltration surface. This is referred as infiltration distance. The slope is frequently the same slope as the ground surface but this should be estimated during site evaluation. The horizontal flow may be defined using Darcy's Law:

dZ

dXKdF =

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where F is the wastewater flow horizontally down slope for unit length of infiltration system, K is the horizontal saturated hydraulic conductivity of the soil horizons above the restricting horizon and episaturation, d is the depth of soil for horizontal transmission or the infiltration distance between the infiltration surface and the top of the restricting horizon or episaturation of wastewater down the slope, and dX/dZ is the slope of the groundwater surface often the same as the slope of the ground surface. Sites with deep permeable surface horizons do not have flow restriction and therefore other factors control the hydraulic linear loading rates. For sites with a shallow limiting flow horizon, the steeper the slope, dX/dZ, the greater the linear loading rate, also, the deeper the shallow permeable horizons or infiltration distance, d, the higher linear loading rate. Sites with the greatest horizontal hydraulic conductivity in the surface horizon will have the greatest hydraulic linear loading rate. Hydraulic linear loading rates may not be limiting to the design of wastewater infiltration systems, particularly those receiving domestic septic tank effluent. In some cases, the supply of oxygen needed to control soil clogging may be limiting. Supply of oxygen to infiltration systems through soil is discussed in a paper by Erickson and Tyler in these proceedings. Saturated hydraulic conductivity needed to estimate design hydraulic linear loading rates is related to soil pore sizes and therefore related to field described soil characteristics similar to determining wastewater infiltration or loading rates. The same soil characteristics used to estimate infiltration rates are used as a part of determining hydraulic linear loading rates. The other site characteristics, including the slope and depth of permeable horizons, are also determined during the site evaluation. Since determining final system design is dependent on soil and site characteristics, the site evaluation is the single most important part of the design. If the site evaluation is done incorrectly, the rest of the design will be incorrect.

ESTIMATING HYDRAULIC LOADING RATES Table I is for estimating wastewater infiltration into soil from septic tank effluent (>30 mg L-1 BOD) or low organic strength wastewater (30 mg L-1 BOD) and hydraulic linear loading rates based on field described soil and site characteristics of texture, structure, consistence, horizon thickness, and slope. This table was prepared for field practitioners and is presented here as prepared. Therefore, the table contains units in common use. A similar table with metric units could be prepared. The table is used only for soil horizons of very firm or weaker consistence. Soil horizons of stronger consistence than very firm consistence are not acceptable. Also, the table should not be used for soil horizons with smectitic mineralogy. A soil scientist collects all characteristics used while determining loading rates. To estimate infiltration loading rates for wastewaters of either greater or less than 30 mg L-1 BOD or to determine hydraulic linear loading rate, soil characteristics related to infiltration or hydraulic conductivity are needed. Texture, structure, consistence, and mineralogy are most important. Since all design values are estimated from the same soil characteristics, only one table of values is needed. To use the table, the soil must have a consistence of very firm or weaker and clay mineralogy should not be smectitic. If these criteria are acceptable, then texture and structure are used. Abbreviations for soil textures are found in the first column to the left in Table 1. Abbreviations are nationally accepted soil science abbreviations of the Natural Resource Conservation Service of the United States Department of Agriculture (Schoeneberger et al., 1998). Within the texture row for the horizon of interest, the soil structure of shape and grade are used to select the row containing the infiltration loading rates depending on the BOD of the applied wastewater. Finally in the same row, an array of hydraulic linear loading rates complete the remainder of the row. Since hydraulic linear loading rate is not dependent on the wastewater quality applied, these values are the same regardless of the application infiltration rate. Hydraulic linear loading rate is also related to the slope of the flow surface and the depth of flow. These values are from the site evaluation and are found to the right of the infiltration rate values at top of the table. Ranges of slope and infiltration distance or the thickness of the horizon are along the top. Hydraulic linear loading rate for a horizon is selected with the row identified by the texture and structure. This is done by selecting the slope of the horizontal flow horizon and then the depth of the horizon for horizontal flow. If there is more than one horizon, the contribution to horizontal flow of each horizon is used to determine the hydraulic linear loading rate. If only a portion of a horizon is transmitting water, only the infiltration distance or distance from the infiltration surface to the limiting condition is used. Values for infiltration hydraulic loading rates and for hydraulic linear loading rates are estimates based primarily on experience. The logic and trends in values presented fit with the scientific basis and with experience. Further research and testing are needed to verify the values. Hydraulic linear loading rates are for domestic wastewater assuming 570 L d-1 per bedroom (150 gpd/bedroom). For other wastewater sources, use safety factors similar to those used for domestic wastewater. The design safety factor is imbedded in the design wastewater flow. Designers using actual wastewater flow rates should assume the values in the table for wastewater infiltration are 5 to 10 times higher than should be used when using actual flows.

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Assume a site has a 7% slope on the limiting horizon. From the top of the limiting horizon to the bottom of the infiltration is 36 cm (14 inches). The horizon is a silt loam, abbreviation SIL, with weak, abbreviation 1, fine subangular blocky, abbreviation BK, structure that is friable and not smetitic. The infiltration loading rate for a wastewater with BOD >30 mg L-1 would be 16 L m-2 d-1 (0.4 gpd/ft2) and 24 L m-2 d-1 (0.6 gpd/ft2) if the BOD were <30 mg L-1. The hydraulic linear loading rate is 11.4 L m-1 d-1 (3.0 gpd/ft) regardless of the wastewater type. For design, there is no need to calculate areas. First determine the linear loading rate from Table 1. From the example above, with a linear loading rate of 11.4 L m-1 d-1 (3.0 gpd/ft) and a wastewater volume of 1700 L d-1 (450 gpd), divide the wastewater volume by the hydraulic linear loading rate to get the length of the system of 46 m (150 feet). The width of a trench is the hydraulic linear loading rate divided by the infiltration hydraulic loading rate. For septic tank effluent and an infiltration hydraulic loading rate of 16 L m-2 d-1 (0.4 gpd/ft2), the width of the system would be 2.3 m (7.5 ft.). This width would be acceptable hydraulically but may not account for the oxygen demand. ... Table 1. Infiltration rates in gal/d/W for wastewater of >30 mg L-1 or wastewater of <30 mg L-1 and hydraulic linear loading rates in gal/d/ft for soil characteristics of texture and structure and site conditions of slope and infiltration distance. Values assume wastewater volume of>150 gal/d/bedroom. If horizon consistence is stronger than firm or any cemented class or the clay mineralogy is smectitic, the horizon is limiting regardless of other soil characteristics. {@ 2000 by E. Jerry Tyler, printed with permission}.

CONCLUSIONS The principals of water movement through wastewater infiltration system clogging layers and saturated horizontal flow away from the zone of infiltration can be used to explain the flow of domestic wastewater into and through soil. However, application of principals does not provide working values for design of onsite wastewater treatment systems. Design hydraulic loading rate estimates based on logic and experience for domestic wastewater applications derived from field described soil and site characteristics are in a single table for use by onsite wastewater specialists.

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Table 1.

Infiltration rates in gal/d/ft2 for wastewater of >30 mg L-' or wastewater of <30 mg L-' and

hydraulic linear loading rates in gal/d/ft for soil characteristics of texture and structure and

site conditions of slope and infiltration distance. Values assume wastewater volume of >150

gal/d/bedroom. If horizon consistence is stronger than firm or any cemented class or the clay

mineralogy is smectitic, the horizon is limiting regardless of other soil characteristics.

{©2000 by E. Jerry Tyler, printed with permission}.

Hydraulic linear loading rate, gal/d/ft

Slope

Infiltration loading 0-4% 5-9% >10%

Soil characteristics rate, gal/da/ft2 Infiltration distance, Infiltration distance, Infiltration

Texture Structure >30 <30 inch inch distance, inch

Shape Grad mg/L mg/L 8-12 12- 24-48 8- 12- 24- 8- 12- 24-

COS, S, LCOS, LS -- OSG 0.8 1.6 4.0 5.0 6.0 5.0 6.0 7.0 6.0 7.0 8.0

FS,VFS,LFS,LVFS -- OSG 0.4 1.0 3.5 4.5 5.5 4.0 5.0 6.0 5.0 6.0 7.0

-- OM 0.2 0.6 3.0 3.5 4.0 3.6 4.1 4.6 5.0 6.0 7.0

PL 1 0.2 0.5 3.0 3.5 4.0 3.6 4.1 4.6 4.0 5.0 6.0

CSL, SL 2 3 0.0 0.0 - - - - - _ _ _ _

PR/B 1 0.4 0.7 3.5 4.5 5.5 4.0 5.0 6.0 5.0 6.0 7.0

K/G 2,3 0.6 1.0 3.5 4.5 5.5 4.0 5.0 6.0 5.0 6.0 7.0

-- OM 0.2 0.5 2.0 2.3 2.6 2.4 2.7 3.0 2.7 3.2 3.7

FSL, VFSL PL 1,2,3 0.0 0.0 - - - - - - - - -

PR/B 1 0.2 0.6 3.0 3.5 4.0 3.3 3.8 4.3 3.6 4.1 4.6

K/G 2,3 0.4 0.8 3.3 3.8 4.3 3.6 4.1 4.6 3.9 4.4 4.9

-- OM 0.2 0.5 2.0 2.3 2.6 2.4 2.7 3.0 2.7 3.2 3.7

L PL 1,2, 3 0.0 0.0 - - - - - - - - -

PR/B 1 0.4 0.6 3.0 3.5 4.0 3.3 3.8 4.3 3.6 4.1 4.6

K/G 2, 3 0.6 0.8 3.3 3.8 4.3 3.6 4.1 4.6 3.9 4.4 4.9

-- OM 0.0 0.2 2.0 2.5 3.0 2.2 2.7 3.2 2.4 2.9 3.4

SIL PL 1,2,3 0.0 0.0 - - - - - - - - -

PR/B 1 0.4 0.6 2.4 2.7 3.0 2.7 3.0 3.3 3.0 3.5 4.0

K/G 2,3 0.6 0.8 2.7 3.0 3.3 3.0 3.5 4.0 3.3 3.8 4.3

-- OM 0.0 0.0 - - - - - - - - -

SCL,CL SICL PL 1,2,3 0.0 0.0 - - - - - - - - -

PR/B 1 0.2 0.3 2.0 2.5 3.0 2.2 2.7 3.2 2.4 2.9 3.4

K/G 2,3 0.4 0.6 2.4 2.9 3.4 2.7 3.0 3.3 3.0 3.5 4.0

-- OM 0.0 0.0 - - - - - - - - -

SC, C, SIC PL 1,2,3 0.0 0.0 - - - - - - - - -

PR/B 1 0.0 0.0 - - - - - - - - -

K/G 2,3 0.2 0.3 2.0 2.5 3.0 2.2 2.7 3.2 2.4 2.9 3.4

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REFERENCES 1. Bouma, J. 1975. Unsaturated flow during soil treatment of septic tank effluent. J. Am. Soc. Civ. Eng. 01(EE6): 967-983. 2. Keys, J.R., E.J.Tyler and J.C. Converse. 1998. Predicting life for wastewater absorption systems. In: D. Sievers (ed.) On-site wastewater treatment. Proc. of the 8th International Symposium on Individual and Small Community Sewage Systems. ASAE. St. Joseph, MI.p. 167-176. 3. Schoeneberger, P.J., D.A. Wysocki, E.C. Benham and W.D. Broderson. 1998. Field book for describing and sampling soils. National Resources Conservation Service, USDA, National Soil Survey Center, Lincoln, NE. 4. Siegrist, R.L. 1987. Hydraulic loading rates for soil absorption systems based on wastewater quality. In: On-site wastewater treatment. Proc. of the 6th National Symposium Individual and Small Community Sewage Systems. ASAE, St. Joseph, MI. p. 232-241. 5. Tyler, E.J. and J.C. Converse. 1984. Soil evaluation and design selection of large or cluster wastewater soil absorption systems. In: On-site wastewater treatment. Proc. of the 4th National Symposium Individual and Small Community Sewage Systems. ASAE, St. Joseph, MI. p. 179-190. 6. Tyler, E.J., E.M. Drozd and J.O. Peterson. 1991. Estimating wastewater loading rates using soil morphological descriptions. In: On-site wastewater treatment. Proc. of the 6th National Symposium Individual and Small Community Sewage Systems. ASAE, St. Joseph, MI. p.192-200. 7. Tyler, E.J. and J.C. Converse. 1994. Soil acceptance of on site wastewater as affected by soil morphology and wastewater quality. In: D. Sievers (ed.) On-site wastewater treatment. Proc. of the 8th International Symposium on Individual and Small Community Sewage Systems. ASAE. St. Joseph, MI. p. 185-194.