New Prague Wastewater Treatment Facility Upgrade

TDD (for hearing and speech impaired only): (651) 282-5332

Printed on recycled paper containing 30% fibers from paper recycled by consumers

ENVIRONMENTAL ASSESSMENT WORKSHEET Note to reviewers: The Environmental Assessment Worksheet (EAW) provides information about a project that may have the potential for significant environmental effects. This EAW was prepared by the Minnesota Pollution Control Agency (MPCA), acting as the Responsible Governmental Unit (RGU), to determine whether an Environmental Impact Statement (EIS) should be prepared. The project proposer supplied reasonably accessible data for, but did not complete the final worksheet. Comments on the EAW must be submitted to the MPCA during the 30-day comment period, which begins with notice of the availability of the EAW in the Minnesota Environmental Quality Board (EQB) Monitor. Comments on the EAW should address the accuracy and completeness of information, potential impacts that are reasonably expected to occur that warrant further investigation, and the need for an EIS. A copy of the EAW may be obtained from the MPCA by calling (651) 297-8510. An electronic version of the completed EAW is available at the MPCA Web site http://www.pca.state.mn.us/news/eaw/index.html#open-eaw. 1. Project Title: New Prague Wastewater Treatment Facility Upgrade 2. Proposer: City of New Prague 3. RGU: Minnesota Pollution Control Agency Contact Person Dennis Seurer Contact Person William J. Lynott and Title Director of Public Works and Title Project Manager Address 118 Central Avenue North Address 520 Lafayette Road North New Prague, Minnesota 56071 St. Paul, Minnesota 55155 Phone (952) 758-4401 Phone (651) 296-7795 Fax (952) 758-6279 Fax (651) 297-2343 4. Reason for EAW Preparation:

EIS Scoping

Mandatory EAW

X

CitizenPetition

RGU Discretion

Proposer Volunteered

If EAW or EIS is mandatory give EQB rule category subpart number and name: Minn. R. 4410.4300,

subp. 18(B) 5. Project Location: County Scott City/Twp New Prague/Helena SO 1/2 SE 1/4 Section 27 Township 113 N Range 23 W

Attachments to the EAW: Attachment 1 – New Prague Wastewater Treatment Facility (WWTF) Location Map; Attachment 2 – New Prague WWTF Location and Planning Boundary Map; Attachment 3 – New Prague Alternative 4 Site Plan; Attachment 4 – Minnesota Department of Natural Resources (DNR) National Heritage Database Review Letter; and Attachment 5 – Minnesota Historical Society Review Letter.

http://www.pca.state.mn.us/news/eaw/index.html#open-eaw

New Prague Wastewater Treatment Facility Upgrade Environmental Assessment New Prague, Minnesota 2 Worksheet

6. Description:

a. Provide a project summary of 50 words or less to be published in the EQB Monitor. The city of New Prague proposes to upgrade its existing wastewater treatment facility (WWTF) to treat an average wet weather flow of 2.50 million gallons per day (mgd) from the currently permitted capacity of 1.378 mgd. The upgrade is to meet new and more stringent discharge limits and to treat greater flows and loads anticipated from future growth.

b. Give a complete description of the proposed project and related new construction. Attach additional

sheets as necessary. Emphasize construction, operation methods and features that will cause physical manipulation of the environment or will produce wastes. Include modifications to existing equipment or industrial processes and significant demolition, removal or remodeling of existing structures. Indicate the timing and duration of construction activities.

New Prague proposes to construct a new WWTF (Project) on property currently owned by the City and located adjacent to the existing wastewater treatment plant (WWTP) (Attachments 1- 3). The proposed treatment process is referred to as an upflow, submerged, aerated, fixed film filter system. The discharge receiving waters will continue to be an unnamed tributary to the East Branch of Raven Stream, which discharges to Sand Creek, which ultimately flows into the lower Minnesota River (Attachment 2). The advantages of this alternative over others evaluated in the facility plan include: 1. A compact plant footprint entirely enclosed within buildings that can provide an aesthetically

pleasing appearance and offer the best opportunity to control plant odors. The relatively small footprint means less excavation and less potential for erosion loss, airborne dust, and displaced habitat for flora and fauna that would be the case with other alternatives. Other than below-grade connections to existing piping, none of the existing facility is anticipated to be remodeled or upgraded. Instead it will likely be demolished, creating an open space equal in area to the proposed Project site.

2. A treatment option that is highly automated but one that likely requires less process control than would a combined trickling filter/activated sludge plant or even an oxidation ditch plant. This would favor the current staff, who have little or no activated sludge operating experience.

3. Great latitude with biosolids disposal by incorporating lime pasteurization of sludge into the alternative, providing the capability of producing either Class A or B biosolids.

4. Staffing requirements comparable to the other alternatives evaluated.

5. Plant construction that will be less disruptive than upgrading the existing facility. Issues such as maintaining treatment during construction should be virtually non-existent.

6. Plant construction that will be completed in less time because there will be no need to sequence construction around existing treatment units. Construction is anticipated to require 18-24 months, and would occur on a year-round basis.


Attachment 3 illustrates the likely arrangement of the proposed Project at the existing site. Three buildings would enclose the entire treatment process. Flow would enter the pretreatment building for preliminary and primary treatment and would flow to the process building for biological (secondary) treatment, effluent filtration and disinfection, and then be discharged through the outfall line. Sludge produced from the primary and secondary treatment stages would be stored in below-ground tanks for subsequent treatment in the biosolids process building. Treated sludge would then be stored as a dewatered cake before being land applied. The pretreatment building would enclose several unit processes including: 1. The preliminary treatment stage of the plant (grit/screening room) where incoming flow metering

would occur and screenings and grit would be removed from the flow.

2. Chemical addition and mixing tanks where a coagulant (ferric chloride) and a polymer would be added to the flow received from the grit/screening room. These chemicals would condition the wastewater for settling in the primary clarifiers. The addition of ferric chloride at this stage results in removal of phosphorus from the wastewater; at this time it is not anticipated there will be a need to add more chemicals to the plant effluent to meet the effluent phosphorus limit.

3. Specifically designed primary clarifiers that treat the flow after chemical conditioning, resulting in an efficient separation of suspended material from the wastewater within a very compact footprint.

4. A chemical storage room for ferric chloride and polymers.

5. A room for an odor scrubber to clean building air before it is exhausted to the atmosphere. A wet chemical scrubber would remove odors such as hydrogen sulfide, ammonia and organic compounds.

6. A wet well and pumping room to pump primary effluent to the process building for further treatment.

7. An electrical room. The process control building would be a multi-story structure containing all remaining treatment operations except sludge processing. 1. Pumped primary effluent would enter the inlet feed box on the upper floor and be distributed by

gravity to the biological treatment stage consisting of: seven up-flow, submerged, aerated, fixed film filter cells that would treat the waste to remove BOD, ammonia and other soluble and insoluble pollutants.

2. Upon entering the treatment cells, the wastewater would be forced upwards through the filter media. The media would be composed of specially manufactured high-density polystyrene beads covered by active biomass. This would provide biological treatment to the wastewater as it flows through the cells. Ceiling plates with regularly spaced nozzles would retain the filter media. The treated water would enter a common water reservoir above the filters, which would provide water for backwash. Each cell would contain approximately 12 vertical feet of media.


3. An air grid below the filter media would maintain aerobic conditions in the filter bed. BOD

would be oxidized by the biomass in the lower section of the filter. When the BOD value falls below a limiting level, nitrification will occur, thereby converting the ammonia to nitrate.

4. Growth of biomass and the retention of the suspended solids in the filter media make periodic backwashing necessary. The process is designed for a typical backwash interval of 24 hours. The backwash sequence would be performed automatically and would be triggered either when a preset time limit has expired or when the head loss across the filter exceeded a pre-determined set point.

5. Seven cells would be constructed, but only four would be equipped to be operational for about the first 10 years. The remaining cells would be put on-line in about year 2020, when flows and organic loads necessitate additional treatment.

6. The process requires no final clarifiers, minimizing space needs. Used backwash water from cleaning the treatment cells would be stored in a tank and eventually pumped to the pretreatment building where it would undergo further treatment and be recycled though the plant.

7. Treated effluent would flow by gravity to an effluent filtration step, where dual media traveling bridge filters would remove the remaining BOD necessary to meet the stringent 5 mg/l effluent limit anticipated to be in the City’s next National Pollutant Discharge Elimination System (NPDES)/State Disposal System (SDS) Permit.

8. Water from the effluent filters would flow by gravity to an ultraviolet light (UV) disinfection system for inactivation of bacteria and then be charged with oxygen to ensure the effluent meets MPCA dissolved oxygen limits before being discharged from the plant.

9. The upper level of the building would enclose facilities such as the control room, offices and laboratory, restrooms and locker facilities, mechanical equipment rooms, etc.

10. Various pumps, air blowers, piping and valves would be located along the pipe and equipment gallery levels within the building interior.

11. A separate room would enclose all electrical equipment. Sludge produced by the treatment process would be pumped to aerated, below-ground storage tanks until ready for processing into a dewatered cake for ultimate disposal. A total of 550,000 gallons of liquid sludge storage would be equally divided between two tanks. An activated carbon style scrubber would scrub odorous air from the tanks. Liquid sludge would be pumped to two belt filter presses for dewatering. This would increase the solids content of the sludge from about 2 percent solids to approximately 20 percent solids so the cake could be further processed to meet MPCA and EPA sludge regulations.

Special equipment would then “pasteurize” the sludge cake by blending it with lime, thereby elevating the pH of the mixture to 12.0 while simultaneously maintaining its temperature at 70°C (158ºF) for 30 minutes or longer. The purpose is to kill pathogens in the sludge. The final product would meet all EPA biosolids criteria and would therefore be considered “Class A” biosolids, suitable for most any


use, including distribution to the public or for use on public areas (roadsides, nurseries, gardens, golf courses, etc.). Class A biosolids are those sludge products that meet EPA’s most stringent requirements for pathogen content. Item 20 of this EAW contains additional information on potential future uses and disposal practices permitted for Class A biosolids. The City of New Prague is not committing to a specific biosolids management disposal plan at this time, but will consider various options as plant flows and loads increase. Disposal options will be based on cost, feasibility, environmental benefit, public acceptance, etc. The pasteurized sludge cake would be isolated from the environment in a covered room with sufficient capacity to hold 180 days of cake volume (approximately 950 cubic yards). A wet chemical scrubber would scrub the air from the biosolids processing areas and the cake storage room.

c. Explain the project purpose; if the project will be carried out by a governmental unit, explain the need for

the project and identify its beneficiaries. The Project’s purpose is to provide wastewater treatment capacity for existing and future development within New Prague. It is expected to considerably improve effluent quality to Phillips Creek, East Branch of Raven Stream, Sand Creek and the lower Minnesota River, as the effluent will be subject to new and more stringent BOD and phosphorus limits. This will benefit residents, area neighbors and all Minnesotans using the local waterways, the lower Minnesota River and the Upper Mississippi River to Lake Pepin. The facility will be constructed, owned, operated and financed by the City of New Prague.

d. Are future stages of this development including development on any outlots planned or likely to happen? Yes No

If yes, briefly describe future stages, relationship to present project, timeline and plans for environmental review. Treatment of municipal wastewater generated in the New Prague vicinity will always be required. When this Project becomes obsolescent it will need to be replaced.

e. Is this project a subsequent stage of an earlier project? Yes No If yes, briefly describe the past development, timeline and any past environmental review.

This Project replaces the existing municipal wastewater treatment system in New Prague.

7. Project Magnitude Data Total Project Area (acres) 4.5 acres (WWTF site) or Length (miles) Number of Residential Units:

Unattached NA

Attached

N/A

maximum units per building

N/A

Commercial/Industrial/Institutional Building Area (gross floor space): total square feet 49,900 Indicate area of specific uses (in square feet): Other Industrial (specify) (Process buildings) = 49,900 Building height 40 feet If over 2 stories, compare to heights of nearby buildings


Existing treatment plant has several buildings that are 1 - 1½ stories tall and several treatment processes

(first and - second stage trickling filters, primary and secondary digesters with gas holder covers) that extend 15ft - 25 ft above grade, so the appearance of the new structures won’t be significantly different from what is on-site today.

8. Permits and approvals required. List all known local, state and federal permits, approvals and financial assistance for the project. Include modifications of any existing permits, governmental review of plans, and all direct and indirect forms of public financial assistance including bond guarantees, Tax Increment Financing and infrastructure.

Unit of Government Type of Application Status MPCA Nondegradation to All Waters Review Completed MPCA Facility Plan Submitted MPCA NPDES/SDS Permit Application To be submitted MPCA Plans and Specifications To be submitted MPCA NPDES General Stormwater Permit for

Construction Activity To be submitted

DNR Natural Heritage and Nongame Database Review

Completed

Minnesota Historical Society Archeological & Historical Review Completed Public Facilities Authority Funding Application May be submitted DNR Temporary Water Appropriations Permit May be submitted 9. Land use. Describe current and recent past land use and development on the site and on adjacent lands.

Discuss project compatibility with adjacent and nearby land uses. Indicate whether any potential conflicts involve environmental matters. Identify any potential environmental hazards due to past site uses, such as soil contamination or abandoned storage tanks, or proximity to nearby hazardous liquid or gas pipelines. The current treatment plant site and the area for the proposed plant upgrade are portions of a larger parcel of land purchased by the City for wastewater treatment in 1966. The current plant was constructed in 1966 and underwent upgrades in 1988 and 2001. Generally, land use in the area, including that around the plant site, is transforming from agricultural/rural community use to single and multi-family residential use including commercial and service industry growth. The current plant site has been in use for approximately 40 years. Retaining the site for future use has several advantages:

The City owns the property; Sewer infrastructure is already routed to the site and significant new infrastructure costs can be

avoided; The main lift station and flow equalization basin can be reused; and The site is large enough to accommodate an expansion even while the existing plant continues to

operate. Unfortunately, but as often happens, development has encroached upon the plant site necessitating the City adopt a “good neighbor” policy and manage the site for future use with careful consideration for the potential for odors, accidental hazardous chemical releases, traffic and site aesthetics. Each of these issues will be addressed by:


Constructing a facility with a compact footprint with pleasing architectural features; Enclosing all treatment processes within buildings or covered tanks; Scrubbing exhaust air streams to remove objectionable odors; Using ultraviolet light (UV) as a disinfection technology vs. chlorine, eliminating issues of delivery,

storage and handling of large quantities of a dangerous, gaseous chemical; Storing other treatment chemicals within buildings, with containment barriers; Producing Class A biosolids; and Producing a cake sludge, which will minimize the volume of sludge that will be trucked from the

site. There are no known issues or concerns associated with environmental hazards such as soil contamination, abandoned storage tanks or proximity to hazardous liquid or gas pipelines.

10. Cover Types. Estimate the acreage of the site with each of the following cover types before and after development:

Before After Before After Types 1-8 wetlands 0 0 Lawn/landscaping 0 1.32 Wooded/forest 0 0 Impervious Surfaces 0. 2.34 Brush/grassland 3.4 0 Other (sludge lagoon) 0.85 0.59 Cropland 0 0 TOTAL 4.25 ac 4.25 ac 11. Fish, Wildlife, and Ecologically Sensitive Resources. a. Identify fish and wildlife resources and habitats on or near the site and describe how they would be

affected by the project. Describe any measures to be taken to minimize or avoid impacts. There is no fish habitat within the Project limits. Grass, shrubs, open spaces and the sludge lagoon, flow equalization basin and the abandoned effluent polishing pond provide habitat for birds, small animals, and reptiles. Shrub land and grassland areas will be converted to lawn, building and roadway areas as noted in Item 10. Approximately 0.26 acres of the sludge lagoon will be filled to allow space for new structures. The remaining basin will be cleaned of sludge deposits and allowed to remain. The existing equalization basin and the existing pond (21 acres combined) will not be impacted by construction activity.

b. Are any state (endangered or threatened) species, rare plant communities or other sensitive ecological resources such as native prairie habitat, colonial waterbird nesting colonies or regionally rare plant communities on or near the site? Yes No

If yes, describe the resource and how it would be affected by the project. Indicate if a site survey of the resources has been conducted and describe the results. If the DNR Natural Heritage and Nongame Research program has been contacted, give the correspondence reference number.

ERDB 20040440

Describe measures to minimize or avoid adverse impacts. Based on the Minnesota Natural Heritage database review, there are no known occurrences of rare species or natural communities in the Project area (see Attachment 4).


12. Physical Impacts on Water Resources. Will the project involve the physical or hydrologic alteration

(dredging, filling, stream diversion, outfall structure, diking, and impoundment) of any surface waters such as a lake, pond, wetland, stream or drainage ditch? Yes No If yes, identify water resource affected. Describe alternatives considered and proposed mitigation measures to minimize impacts. Give the DNR Protected Waters Inventory (PWI) number(s) if the water resources affected are on the PWI.

Approximately 0.26 acres of the existing sludge lagoon will be filled to create space for new structures.

13. Water Use. Will the project involve installation or abandonment of any water wells, connection to or

changes in any public water supply or appropriation of any ground or surface water (including dewatering)? Yes No If yes, as applicable, give location and purpose of any new wells; public supply affected, changes to be made, and water quantities to be used; the source, duration, quantity and purpose of any appropriations; and unique well numbers and DNR appropriation permit numbers, if known. Identify any existing and new wells on the site map. If there are no wells known on site, explain methodology used to determine. Dewatering wells may be needed for construction. Location, depth and duration of pumping are not known at this time.

14. Water-related land use management districts. Does any part of the project involve a shoreland zoning district, a delineated 100-year flood plain, or a state or federally designated wild or scenic river land use district? Yes No If yes, identify the district and discuss project compatibility with district land use restrictions.

15. Water Surface Use. Will the project change the number or type of watercraft on any water body?

Yes No If yes, indicate the current and projected watercraft usage and discuss any potential overcrowding or conflicts with other uses.

16. Erosion and Sedimentation. Give the acreage to be graded or excavated and the cubic yards of soil to be moved: 4.5 acres; 13,000 cubic yards. Describe any steep slopes or highly erodible soils and identify them on the site map. Describe any erosion and sedimentation control measures to be used during and after project construction.

This Project will require a NPDES Phase II, General Stormwater Permit for Construction Activity. Erosion control will be maintained throughout the construction period. Temporary erosion control will comply with MPCA, NPDES Phase II requirements. Erosion and sedimentation control will be in place prior to the start of construction and will remain until protective cover has been established. Temporary erosion control devices may include silt fences, straw bales and storm sewer inlet protection. Additional erosion control methods for steep slopes or highly erodible soils should not be needed.


17. Water Quality - Surface Water Runoff. a. Compare the quantity and quality of site runoff before and after the project. Describe permanent

controls to manage or treat runoff. Describe any storm water pollution prevention plans. All areas disturbed by construction will be returned to pre-construction conditions. Construction site best management practices will be employed for managing and treating site runoff during construction. A Stormwater Pollution Prevention Plan (SWPP) will be developed and followed to manage and minimize runoff impacts during and after construction is complete. Upon completion, vegetative cover will be re-established in all disturbed areas. No significant long or short-term impacts are expected in runoff quantity or quality.

b. Identify routes and receiving water bodies for runoff from the site; include major downstream water

bodies as well as the immediate receiving waters. Estimate impact runoff on the quality of receiving waters.

Runoff from the site would generally flow to the southwest through ditches, storm sewers or overland routes to Phillips Creek and then northwest, joining drainage flows from the remainder of the Phillips Creek watershed. After implementation of erosion control measures, best site management practices, and the SWPP, runoff impacts are anticipated to be minimal.

18. Water Quality – Wastewater. a. Describe sources, composition and quantities of all sanitary, municipal and industrial wastewater

produced or treated at the site. The New Prague WWTF receives domestic, commercial and light industrial wastewater (no food processing) for treatment. In addition to flow and load from the City, about 40,000 gallons/day of wastewater are also received from residential development along Cedar Lake, located about three miles northeast of the City. A pump station and forcemain conveys the wastewater to the City’s collection/treatment system. The following table illustrates the composition and quality of the current wastewater and that projected for year 2030. All flow and pollutant values include the City of New Prague and the residential development at Cedar Lake.


Composition and Quantity of Wastewater

Current Year 2030 Flow

• Average wet weather, mgd 1.15 2.50 Biochemical Oxygen Demand

• Annual average, lb/day 1,120 3,038 Total Suspended Solids

• Annual average, lb/day 1,140 3,636 Total Kjeldahl Nitrogen

• Annual average, lb/day 300 750 Total Phosphorus

• Annual average, lb/day 45 115 b. Describe waste treatment methods or pollution prevention efforts and give estimates of composition

after treatment. Identify receiving waters, including major downstream water bodies, and estimate the discharge impact on the quality of receiving waters. If the project involves on-site sewage systems, discuss the suitability of site conditions for such systems.

Refer to Project description in Item 6B.

The new treatment plant will meet the effluent limits proposed for issuance in the facility’s next NPDES permit, as shown in the following table. The size of the proposed flow increase makes a non-degradation analysis mandatory and this analysis has been completed and submitted to the MPCA. The limits shown in the table were issued by the MPCA for facility planning purposes, and are believed to be representative of the values that will be required when the non-degradation review process has been completed. The proposed Project meets the definition of a “significant discharge” as stated in Minn. R. 7050.0185. This in turn creates a requirement for a nondegradation of all waters review by MPCA. This review has been completed, and final effluent limits for the Project have been developed based on it. These limits are presented in the following table. The mass load values in the table were determined by the MPCA based on the agency’s water quality database and computer modeling.


Proposed NPDES/SDS Permit Limits

Parameter Concentration Limit A Mass Limit A

Biochemical Oxygen Demand 5 mg/l 47.39 kg/day Total Suspended Solids 30 mg/l 284.32 kg/day Ammonia Nitrogen

Summer 1.0 mg/l 9.48 kg/day Fall 1.9 mg/l 18.01 kg/day Winter 7.7 mg/l 72.98 kg/day Spring 1.3 mg/l 12.32 kg/day

Total Phosphorus May - September 0.55 mg/l 5.20 kg/day October - April 1.0 mg/l 9.48 kg/day

Fecal Coliform Group Organisms 200 MPN/100 ml (April - October)

Not applicable

pH 6.0 - 9.0 (standard units)

Not applicable

Dissolved oxygen (daily minimum)

7.0 mg/L Not applicable

Notes: A Values are calendar month averages, except for Fecal Coliforms, which is a calendar

month geometric mean. The receiving waters will continue to be an unnamed tributary to the East Branch of Raven Stream, which discharges to Sand Creek, which ultimately flows into the lower Minnesota River (Attachment 2). The impact of the proposed effluent limits on receiving waters is expected to be an improvement from current conditions due to the imposition of a mass load limit on phosphorus and a reduction in both concentration and mass loading of CBOD.

c. If wastes will be discharged into a publicly owned treatment facility, identify the facility, describe

any pretreatment provisions and discuss the facility’s ability to handle the volume and composition of wastes, identifying any improvements necessary.

See Item 6.

d. If the project requires disposal of liquid animal manure, describe disposal technique and location and

discuss capacity to handle the volume and composition of manure. Identify any improvements necessary. Describe any required setbacks for land disposal systems.

N/A.

19. Geologic hazards and soil conditions a. Approximate depth

(in feet) to: Groundwater:

(see soil descriptions)

minimum;

average.

Bedrock:

150

minimum;

150 - 200

average.


Describe any of the following geologic site hazards to ground water and also identify them on the site

map: sinkholes, shallow limestone formations or karst conditions. Describe measures to avoid or minimize environmental problems due to any of these hazards. None Identified.

b. Describe the soils on the site, giving SCS classifications, if known. Discuss soil granularity and

potential for groundwater contamination from wastes or chemicals spread or spilled onto the soils. Discuss any mitigation measures to prevent such contamination. Soils New Prague and the surrounding area have soils that were formed through the action of glaciers. The parent material of most is glacial till, but a few were formed from sandy and gravelly glacial drift. Mixed with these soils are pockets of organic peat soils and marshes. A few soils were formed by the action of small streams, which flow through the area. The following soils are predominant at the WWTF site: 1. Clarion (CaB) - This soil series consists of very deep, moderately well drained, moderately

permeable soils formed in glacial till on uplands. The slopes range from 1 to 9 percent. Surface runoff is medium. The seasonal high water table is at depths of 4 to 6 feet between November and July of most years. Under cultivation, vegetation includes corn, soybeans, small grain and legume hay. Native vegetation is tall grass prairie.

2. Webster - Glencoe (Wb) - This soil series consists of very deep, poorly drained, moderately permeable soils formed in glacial till or local alluvium derived from till on uplands. Slopes typically range form 0 to 3 percent. Since these soils are poorly drained, most areas are artificially drained with tile and open ditches. Runoff is slow. The seasonal high water table is at depths of 0 to 1 foot from November to July in most years, where undrained. Uses and vegetation in Webster series soil when cultivated included corn and soybeans, small grain and hay. Native vegetation is primary wet-site tall prairie grasses.

3. Lester (Lc C2) - This soil series consists of very deep, well-drained soils that formed in calcareous loamy glacial till on till plains and moraines. These soils have moderate permeability. Slopes range from 5 to 70 percent. Run-off is medium to high. When cultivated, Lester soils are mostly cropped to corn and soybeans, with some in pasture and forest. Native vegetation is savanna.

4. Glencoe (Ga) - This soil series consists of very deep, very poorly drained soils that were formed in loamy sediments from glacial till on glacial moraines. These soils have moderate or moderately slow permeability. Slopes are 0 to 1 percent. This soil when cultivated is drained and cropped to corn and soybeans. Native vegetation was a wet site plant community of the tall grass prairie plant formation.

5. Le Sueur-Lester (Lf) - This soil series consists of very deep, somewhat poorly drained soil that formed in calcareous loamy glacial till on moraines. These soils have moderate permeability. Slopes range from 1 to 3 percent. When cultivated, crops on Le Sueur soils include corn, soybeans, grain and hay. Native vegetation was deciduous forest, dominantly elm, basswood and maple in some areas and oak with prairie and brush understory in the timber outliers with the prairie. An apparent water table is at 1.5 to 2.5 feet during November to June in most years.


6. Peat (PbA) - These soils consist of deep deposits of peat on slopes of 2 to 6 percent. Ground water contamination potential from spilled liquids would vary depending upon the specific soil type encountered at the spill site. Several soil types are moderately permeable (Clarion, Webster-Glencoe, Lester, Le Sueur-Lester) whereas the Glencoe series has moderate to moderately slow permeability. Some of the soil types lie on sloping ground, which will cause spilled liquids to flow to lower areas where surface containment and removal may be possible. Spills during construction (gasoline, petroleum products, paints or other protective coatings, etc.) would be the responsibility of the contractor to clean up, or if beyond his capability, specialized clean-up subcontractors will be hired at the contractor’s expense.

20. Solid Wastes, Hazardous Wastes, Storage Tanks a. Describe types, amounts and compositions of solid or hazardous wastes, including solid animal

manure, sludge and ash, produced during construction and operation. Identify method and location of disposal. For projects generating municipal solid waste, indicate if there is a source separation plan; describe how the project will be modified for recycling. If hazardous waste is generated, indicate if there is a hazardous waste minimization plan and routine hazardous waste reduction assessments. Solid Waste/Hazardous Waste The existing plant will be demolished once the new facility is on-line. Demolition debris will be deposited in approved demolition landfills and in accordance with applicable solid waste regulations. Construction debris will be handled similarly. Materials containing asbestos (insulation, tile, etc.) will be removed by licensed remediation contractors following State/Federal guidelines and disposed of according to regulation. The new WWTF will be capable of producing exceptional quality Class A biosolids via a lime pasteurization process. The end product will comply with MPCA/EPA 503 sludge regulations and will be of such quality the biosolids could be disposed of or distributed to the general public without regard to site or other restrictions. Class A sludge cake would be stored in a covered bunker until land applied or otherwise distributed for use. Screenings and grit produced by the treatment process would be washed, dewatered and disposed of at a landfill.

b. Identify any toxic or hazardous materials to be used or present at the site and identify measures to be used to prevent them from contaminating groundwater. If the use of toxic or hazardous materials will lead to a regulated waste, discharge or emission, discuss any alternatives considered to minimize or eliminate the waste, discharge or emission. Materials Used/Stored Treatment of wastewater will entail using several chemicals that will require precaution in use, handling, and storage:


Ferric chloride will be used to chemically condition the wastewater for settling in the primary clarifiers and to accomplish phosphorus removal. This chemical will be stored in appropriate vessels prior to use and within rooms designed with spill containment features.

Polymers will be used with ferric chloride to condition wastewater prior to clarification and for sludge thickening/dewatering. This chemical will be stored in appropriate vessels prior to use and within rooms designed with spill containment features.

Lime will be mixed with dewatered sludge to accomplish pasteurization of the product, thereby producing “Class A” biosolids. Will be stored in a specially designed silo with dust filtration equipment. The silo would be located within a building.

Sodium hypochlorite will be used within wet chemical scrubbers for odor control. This chemical will be stored in appropriate containers within rooms designed with spill containment.

Sodium hydroxide - will be used within wet chemical scrubbers for odor control. Chemical will be stored in appropriate containers within rooms designed with spill containment.

Gasoline or diesel fuel - will be used to fuel auxiliary generator to produce power during outages. Will be stored in appropriate vessels prior to use with either containment facilities or double wall construction with leak detection systems.

c. Indicate the number, location, size and use of any above or below ground tanks to store petroleum

products or other materials, except water. Describe any emergency response containment plans.

Tanks Wastewater treatment will involve use of the following above or below ground tanks:

Grit removal tanks (2) Chemical conditioning tanks (8) Primary clarifier tanks (2) Biological treatment cells (7) Effluent filter cells (2) Chemical storage tanks for ferric chloride and polymers (2 each) Liquid sludge storage tanks (2) Sodium hydroxide and sodium hypochlorite storage tanks (3 each) Ultraviolet light channels (2) Wastewater and sludge pumping wet wells (various) Lime silo (1) Gasoline or diesel fuel tank (1)

Process tankage will be constructed of reinforced concrete. Chemical storage tanks will be made of materials appropriate for the stored material.

21. Traffic. Parking spaces added: 10 Existing spaces (if project involves expansion): N/A

Estimated total average daily traffic generated: N/A Estimated maximum peak hour traffic generated (if known) and its timing: N/A Provide an estimate of the impact on traffic congestion affected roads and describe any traffic improvements necessary. If the project is within the

Twin Cities metropolitan area, discuss its impact on the regional transportation system. A total of ten parking spaces are anticipated for the new plant. Current staffing is three full time employees. Anticipated staffing for the new plant would range from 3 to 7 employees. Construction work will increase traffic volumes on local roadways, but no long term impact on local traffic is anticipated. Cake sludge disposal from the plant will result in fewer hauled loads than would be anticipated from a liquid sludge treatment/storage alternative.


22. Vehicle-related Air Emissions. Estimate the effect of the project’s traffic generation on air quality,

including carbon monoxide levels. Discuss the effect of traffic improvements or other mitigation measures on air quality impacts. Note: If the project involves 500 or more parking spaces, consult EAW Guidelines about whether a detailed air quality analysis is needed. See Item 21 above. No adverse effects anticipated.

23. Stationary Source Air Emissions. Describe the type, sources, quantities and compositions of any emissions from stationary sources of air emissions such as boilers, exhaust stacks or fugitive dust sources. Include any hazardous air pollutants (consult EAW Guidelines for a listing), any greenhouse gases (such as carbon dioxide, methane, and nitrous oxides), and ozone-depleting chemicals (chlorofluorocarbons, hydrofluorocarbons, perfluorocarbons or sulfur hexafluoride). Also describe any proposed pollution prevention techniques and proposed air pollution control devices. Describe the impacts on air quality. Plant heat will be provided by small boiler systems, unit heaters or make-up air units operating on natural gas. Emissions are not expected to be significant. The auxiliary generator will operate only during power outages, and expected to be of limited duration.

24. Odors, noise and dust. Will the project generate odors, noise or dust during construction or during operation? Yes No

If yes, describe sources, characteristics, duration, quantities or intensity and any proposed measures to mitigate adverse impacts. Also identify locations of nearby sensitive receptors and estimate impacts on them. Discuss potential impacts on human health or quality of life. (Note: fugitive dust generated by operations may be discussed at item 23 instead of here.) Dust and noise will be generated during construction. Both dust and noise will be controlled to the extent possible. Water trucks will be used during dry or windy conditions and construction noise will be limited to daylight hours. Permanent vegetation will be established both as an erosion control measure and to minimize dust generation after construction is complete. Wet chemical odor scrubbing will be used throughout the plant to rid exhaust air streams of objectionable odors, as residential development is encroaching upon the plant site. Future land use planning around the area of the treatment plant is anticipated to be low density residential.

25. Nearby resources. Are any of the following resources on or in proximity to the site? a. Archaeological, historical, or architectural resources? Yes No b. Prime or unique farmlands or land within an agricultural preserve? Yes No c. Designated parks, recreation areas, or trails? Yes No d. Scenic views and vistas? Yes No e. Other unique resources? Yes No If yes, describe the resource and identify any project-related impacts on the resources. Describe any

measures to minimize or avoid adverse impacts.


The city’s Comprehensive Plan recognizes a sliding hill recreation area within 1/4 mile of the plant. This should not be affected by the Project.

26. Visual impacts. Will the project create adverse visual impacts during construction or operation? Such as glare from intense lights, lights visible in wilderness areas and large visible plumes from cooling towers or exhaust stacks? Yes No If yes, explain.

27. Compatibility with plans and land use regulations. Is the project subject to an adopted local comprehensive plan, land use plan or regulation, or other applicable land use, water, or resource management plan of a local, regional, state or federal agency? Yes No

If yes, describe the plan, discuss its compatibility with the project and explain how any conflicts will be resolved. If no, explain. The city has a Comprehensive Plan updated in 2004 and adopted in 2005. The facility complies with this plan.

28. Impact on infrastructure and public services. Will new or expanded utilities, roads, other infrastructure or public services be required to serve the project? Yes No If yes, describe the new or additional infrastructure or services needed. (Note: any infrastructure that is a connected action with respect to the project must be assessed in the EAW; see EAW Guidelines for details.)

29. Cumulative impacts. Minn. R. 4410.1700, subp. 7, item B requires that the RGU consider the

“cumulative potential effects of related or anticipated future projects” when determining the need for an environmental impact statement. Identify any past, present or reasonably foreseeable future projects that may interact with the project described in this EAW in such a way as to cause cumulative impacts. Describe the nature of the cumulative impacts and summarize any other available information relevant to determining whether there is potential for significant environmental effects due to cumulative impacts (or discuss each cumulative impact under appropriate item(s) elsewhere on this form). This Project is in response to community growth in New Prague. Because public infrastructure projects like wastewater treatment plants are designed with a long range perspective, the new plant will have some reserve capacity. This could stimulate additional growth. Such growth would be subject to federal, state, and local laws designed to limit the environmental impacts associated with it. It would also be subject to environmental review requirements applicable at the time.

30. Other Potential Environmental Impacts. If the project may cause any adverse environmental impacts not addressed by items 1 to 28, identify and discuss them here, along with any proposed mitigation. None anticipated.

31. Summary of issues. List any impacts and issues identified above that may require further investigation before the project is begun. Discuss any alternatives or mitigative measures that have been or may be considered for these impacts and issues, including those that have been or may be ordered as permit conditions.

Summary Four alternatives for upgrading or replacing the existing WWTF were evaluated in the Facility Plan; they included:


Upgrading the existing trickling filter treatment plant and adding new activated sludge treatment

(referred to as Alternative 2a); Constructing a new oxidation ditch facility at the existing plant site and abandoning the existing

facility (referred to as Alternative 2b); Constructing a new oxidation ditch facility at a new site to the northwest or northeast of the City and

abandoning the existing plant (referred to as Alternatives 3a and 3b); and Constructing a new upflow, aerated biological filter treatment facility at the existing plant site and

abandoning the existing plant (referred to as Alternative 4). Reusing the existing site for wastewater treatment (Alternatives 2a, 2b and 4) provides the following advantages:

The City owns the property; Sewer infrastructure is already in place and significant new infrastructure costs can be avoided; and The existing main lift station and flow equalization basin can be reused.

The principal disadvantages of continued use of the existing site include:

The proximity of current housing developments and the potential for land use conflicts; The added cost of equipment for plant odor control; and Future expansion of the current trickling plant (Alternative 2a) would be difficult because of lack of

space to enlarge or duplicate the core treatment units. Relocating the treatment facility to the northwest or northeast of the City (Alternatives 3a and 3b) would have the advantage of allowing a site to be chosen that best matches community growth and the space needs of the facility, thereby minimizing conflicts with incompatible land uses, but would also have several disadvantages, including:

The need to purchase a large tract of land (40 – 80 acres); The possibility such an acreage would not be available or available only at a high cost; Public opposition to relocation; The possibility of lengthy environmental reviews before the site could be approved for use; and The need to construct new pipelines and pumping stations in areas not yet ready for development.

Recommended Alternative Alternative 4, constructing a new upflow, submerged, aerated biological filter treatment plant and abandoning the existing trickling filter plant was recommended because of the following advantages it offers:

A compact footprint, entirely enclosed within buildings that will provide an aesthetically pleasing appearance and offer the best opportunity to control plant odors;

A highly automated treatment option requiring less process control than would a combined trickling filter/activated sludge plant or an oxidation ditch plant, which favors the current staff that have little or no activated sludge operating experience;

Great latitude with biosolids disposal by incorporating lime pasteurization of sludge and creating the opportunity to produce either Class A or B biosolids;

Staffing requirements comparable to the other alternatives evaluated; Plant construction that will be less disruptive than upgrading the existing facility, meaning issues

such as maintaining treatment during construction should be virtually non-existent; and Plant construction that can be completed in less time because there will be no need to sequence

construction around exiting treatment units.

http://www.mnplan.state.mn.us

Documents

New Prague Wastewater Treatment Facility Upgrade