CITY OF PENTICTON Liquid Waste Management Plan … Stage 2 pages 89-113.pdf · Liquid Waste Management Plan Stage 2 ... Membrane Bioreactor ... CITY OF PENTICTON Liquid Waste Management

CITY OF PENTICTON Liquid Waste Management Plan Stage 2 – FINAL REPORT

• Piping systems from the primaries to the bioreactors – there are some existing pipelines that are available for reuse.

• Equalization would be provided in the old secondary clarifiers. An existing chamber adjacent the clarifiers would be utilized as a control chamber to allow flows to be diverted to the equalization tanks during peak periods, and returned during low flows. Piping and pumping systems would be required on the underdrains of the old clarifiers.

Secondary Treatment

The secondary treatment system is the same as for Option 1 – aeration upgrades, flow splitting to clarifiers, new clarifiers and RAS pump station.

Tertiary Treatment

With the use of the contact chamber as a primary clarifier, the use of UV for disinfection is the preferred option both from a spacial and environmental standpoint. There is the potential to construct a new UV channel and building adjacent the filter building and new primary clarifier however this does limit the access to these areas and it would require the building to be within a 6 meter setback from the property line.

For this option, we have abandoned the use of the existing low head filters and planned for installation of a new Disc filter system. These filters can be installed in the existing filter building, ultimately there would be 4 installed for design flows of 27 ML/d – 3 operating and one standby. There is the potential to utilize only 3 as typically these filters can remain in operation while components are service. However at this stage we have planned for 4. Drawing 10 provides a layout of the filter building that would allow the construction to proceed while the existing filters (2) remain in operation.

There is sufficient space within the filter building to install the UV disinfection. This would consist of low pressure UV lamps installed in 2 parallel channels. In addition to the filters and UV system, the non potable water pumps used for supplying process water and a hypochloride system for disinfection of the process and effluent irrigation water would be installed in this building. The existing piping systems would be reused in most cases with a new pipeline required to carry final effluent to the existing outfall.

Solids Handling System

The solids handling system noted in Option 1 would be incorporated in this option.

Option 3 – Membrane Bioreactor

Option 3 is similar to Option 2 with the exception of secondary and tertiary treatment. Conversion of one train of the bioreactor process to a membrane bioreactor system (MBR) would replace the requirement to add secondary clarifiers and filtration systems. The MBR system consists of a suspended growth biological reactor integrated with an ultrafiltration

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membrane system. There are various ultrafiltration membrane systems available. For the purpose of the LWMP, we have incorporated the hollow fibre type system.

The ultrafiltration membranes are immersed in an aeration tank in direct contact with the mixed liquor. A pumping system creates a vacuum in the hollow fibres which draws treated water through them. The treated water (permeate) is of high quality such that it can be directed to disinfection without further clarification or filtration. The MBR technology permits bioreactor operation with higher concentrations of mixed liquor (6,000 to 10,000 mg/l) which will increase the overall capacity of the bioreactor.

In order to provide 27 ML/d per day capacity in the bioreactor, each train will have approximately 13.5 ML/d flow through it. Train 1 of the bioreactor would remain as a conventional system utilizing the existing clarifiers and an upgraded filter system. Train 2 would have cell 10 converted to the immersion tank for membrane cassettes, with cell 11 acting as the building for installation of the mechanical/electrical system, plus various chemical systems, controls and maintenance areas. A building would be constructed over both cells, however cell 10 would just be a shell type construction to provide protection of the various components from severe winter conditions.

Drawings 11 provides an overall schematic of Option 3, Drawing 12 and 13 provide conceptual layouts of cells 10 and 11 of the bioreactor, and the filter building. A description of each unit process is as follows.

Preliminary Treatment

The preliminary treatment is similar to Options 1 and 2 with the exception of the screening. Due to the presence of the membranes, removal of solids to 1 to 2mm is required. This typical requires installation of both a coarse and fine screening mechanism. The second screening system would be retrofit into the existing chlorine and sulfur dioxide storage rooms adjacent the screening building.

Primary Treatment

Similar to option 2, the existing contact chambers would be utilized as primary clarifiers with the abandoned secondary clarifiers providing equalization storage.

Secondary Treatment

Train 1 of the bioreactor would treat 13.5 ML/d with the use of cells 10 and 11. Fine bubble diffusers would be installed in these cells, the aeration control system would be upgraded similar to all options (including odour blower upgrades and a permanent building).

Train 2 of the bioreactor would have the membranes installed in cell 10. There would be 3 rows of cassettes, each with 7 cassettes (each cassette is capable of treating approximately 670m3/day for a total of 14 ML/d). There is sufficient room in the cell to



leave space for an 8th cassette for future expansion capacity if the inlet and outlet distribution channels are located in cells 9 and 11 respectively (see Drawing 12 for layout). Some of the existing channels on the sides of the tank must also be removed. Cell 11 is converted into a building for housing pumping and blower equipment, chemical systems, electrical/control systems, and maintenance.

A deoxidation (Deox) system is required for process operation. One option for the Deox consists of a recycle of approximately 2.3 times the influent. Primary influent must be added to the Deox flow (0.1 x primary influent) to help reduce oxygen levels. Figure 4.1 provides a sketch of the flow schematic. The existing equalization tanks would be used for the Deox system. Some existing piping systems can be reused, new return piping is required. Existing pumps in the equalization tank would have to be upsize to match flow rates. There are other options to consider if further engineering design work was considered for this option.

Figure 4.1

Deox Flow Schematic

Waste sludge from the membranes would be piped to the existing WAS lines. Permeate (treated effluent) would be pumped to the UV system in the filter building.

There is no requirement to add clarifiers as the flow they would receive in this scenario is less than the flow they are currently treating.

Tertiary Treatment

Tertiary Treatment for the MBR flow is not required other than disinfection. The flow from Train 1 would require filtration. Filtration would be provided by two disk filter units



in the existing filter building. UV disinfection is also included in this building together with non potable water pumps and hypochloride disinfection system. Drawing 13 provides a layout of the filter building.

Solids Handling

The solids handling system for this option is the same as the other 2 options.

Miscellaneous Upgrades Common to All Options

In addition to the work defined in each unit process, there are other components of the plant that need to be upgraded. These include adding to the administration building to provide addition staff facilities, upgrading the standby power supply to provide sufficient standby power to operate critical unit processes, adding a second odour blower for peak day operation and standby, and adding a septage receiving and pretreatment facility.

The Regional District of Okanagan Similkameen and the City of Penticton have an agreement in principle for construction of a septage receiving facility at the WWTP. This would consist of a receiving area complete with flow metering, sampling, and billing/recording equipment; screening, pumping and odour control; and piping systems to the plant influent. The current plan for this facility is to complete the design of this facility in 2006 with construction in 2007.

4.9.2 Disposal Options

There are two basic options for disposal of treated effluent. These include:

Option D1 – Maintain Existing: The existing system which consists of river discharge and spray irrigation. This system could be expanded by adding irrigation areas either within the City or on Penticton Indian Band lands. Effluent irrigation can be used to offset potable water demands or irrigate “dry” lands. Either alternative is considered to be beneficial reuse of the water. There is also the potential to dispose of effluent to the Oxbows to increase circulation and potentially improve water quality in these bodies of water. A pilot study would be necessary to determine the impact of this method of disposal. It should, however, be noted that all of the oxbows with the exception of the most southerly one, discharge to the river channel, so dilution provided by river channel flows would still govern the volume available for discharge. The most southerly Oxbow does discharge to Skaha Lake, however its outlet is onto the beach front.

There is also the potential to relocate the river discharge location to a point downstream of areas used for recreational purposes. South of the Highway 97 bridge, there are no recreational users in the channel due to safety concerns with water currents. A pipeline installed to carry effluent irrigation to the south end of Penticton could also be designed to outlet all or a portion of the river outfall downstream of the recreational use area.

Option D2 – New Outfall: A deep lake outfall to Skaha Lake in combination with effluent irrigation and possible disposal to the oxbows.



Ongoing disposal to the river channel (option D1) will be impacted by a number of factors. Dilution, as noted in Section 3, will not become an issue until approximately 2019 at the regulatory ratio of 10:1 and absolute minimum river flows of 3 m3/sec. At lower quartile river flows, the 10:1 dilution is not reached until after 2024 during winter months. Minimum dilutions during recreational use season are approximately 20:1 in 2024 at lower quartile flows. These calculations are based on current population projections with no reduction in per capita flows which hopefully can be achieved through source control programs.

Although the regulatory requirements are met and the risk to human health does not appear to be an issue based on the analysis completed by BC Centre for Disease Control, public perception may become an issue as dilutions reach lower levels. The questionnaire results noted in Section 5 indicate the majority of the public chose 50:1 as the desired dilution level. At a river flow of 1470 ML/d, the median flow during summer months, the dilution at 2024 maximum daily flow is 49:1 (and 57:1 at mean river flow). With increased use of effluent irrigation combined with the potential to relocate the river outfall to beyond the recreational use area in the river channel, dilution ratios in the river channel should not be a concern within the current planning horizon.

The other option for disposal (D2) would be a deep lake outfall to Skaha Lake. A pipeline could be laid from the treatment plant to Skaha Lake and extended into the Lake approximately 750m to a depth of 40m. Dilution and dispersion studies would be required to determine how the treated effluent would be dispersed in the lake, however at this depth it is not expected to create any problems.

4.10 COST ESTIMATES

The following cost estimates are prepared to give order of magnitude costs for comparison of options. These estimates are conceptual in nature and will require much more detailed engineering work to confirm the accuracy of them. Construction and equipment costs have increased dramatically in the last two years. The figures provided are our best estimate of probable costs based on the level of detail available at this stage and equipment costs provided by suppliers. Prior to preparing budgets for construction, the City must undertake more detailed engineering studies of the selected option. Breakdowns of the cost estimates are provided in Appendix D. All costs are in 2005 dollars and include a 25% allowance for contingencies, 10% for engineering, and 5% for interim financing. GST is not included.

The cost estimates are based on a treatment capacity of 27 ML/d and include all upgrades to the unit processes to meet these flows. A number of the unit process upgrades can be staged over time, however, for comparison of options, total costs are generated. Tables 4.4 and 4.5 provide a summary of the costs for treatment and disposal options.



TABLE 4.4 Summary of Costs for Treatment Options

TREATMENT PROCESS

Option Preliminary Primary Secondary Tertiary Solids

Handling Miscellaneous Total

Option 1

Upgrade Existing

$1,255,000 $1,901,000 $5,086,000 $1,314,000 $4,828,000 $2,165,000 $16,549,000

Option 2

New Primaries

$730,000 $2,733,000 $5,086,000 $3,876,000 $4,828,000 $2,165,000 $19,418,000

Option 3

MBR

$1,408,000 $2,733,000 $12,458,000 $2,576,000 $4,828,000 $2,165,000 $26,168,000

Table 4.5 Summary of Costs for Disposal Options

Option Costs

D1 – Maintain Existing $3,689,000

D2 – New Outfall $7,139,000

Projects include potential to dispose effluent to Oxbows

Irrigation costs include pipelines to south Penticton area and PIB lands, and upgrades to pump stations. For the outfall option, a new pump station would be installed at the south end of Penticton and the existing plant pump station upgraded for supply to PIB lands only.

For Option D1, if a new outfall was installed at the south end of the river channel to dispose a portion of the effluent, the estimated cost would be $5,291,000 – (Option D1(a)).



There is the potential to stage upgrading of the treatment and disposal options. The estimated cost to complete all Category A unit process upgrades for each option is provided in Table 4.6.

Table 4.6 Costs for Category A Unit Processes

Option 1 – Upgrade Existing $13,903,000

Option 2 – New Primaries $15,949,000

Option 3 – MBR $21,552,000

Of the Category A unit processes, certain components can be staged by selecting specific units such as sludge handling, or secondary treatment for Options 1 and 2. For Option 3, MBR, the major cost of investing in the membrane system and conversion of one train of the bioreactor to MBR is required at the outset. You could possibly delay the filter upgrades and conversion to UV disinfection and maintain existing primaries, however the initial cost would still be in the order of $15,000,000.

Staging costs for the disposal options would depend upon where irrigation would take place and if an outfall was to be installed. For adding irrigation supplies to PIB or to the south end of Penticton, additional pumping capacity could be added to the existing pump station (more pumps or replace existing) and pipelines constructed. The cost to supply PIB lands initially would be approximately $1,000,000. Costs to install an outfall without any additional irrigation would be approximately $5,800,000. The outfall pipe would however provide a source for irrigation water to the south end of Penticton – pumping and distribution mains would still be required.

Operating costs for each treatment alternative are also a factor in selecting a preferred option for the LWMP. Table 4.7 provides an estimate of cost for each treatment option as well as the current operating cost. A breakdown of the costs and notes on how the costs were calculated are also included in Appendix E.

Table 4.7 Estimated Annual Operating and Maintenance Costs

OPTION ANNUAL COST

Current System $1,158,000

Option 1 – Upgrade System $1,600,000

Option 2 – New Primaries $1,584,000

Option 3 – MBR $1,787,000



5.0 EVALUATION OF ALTERNATIVES

For any project which deals with Environmental Control facilities, there are a large number of factors to consider when choosing between competing alternatives. These factors can be subdivided or considered under the following area of concern:

Financial

Environmental

Engineering

Social

Political

Financial considerations often override all of the other concerns which tend to be neglected because they are difficult to deal with. The financial evaluation also can be reduced to numbers which are as easy to compare between alternatives. The other non-monetary concerns are not as readily handled.

A numerical evaluation technique has been developed for the comparison of alternatives which considers each of the above factors. Although it is not an exact science, the system does force the consideration of a large number of factors which can influence the choice of system.

The Treatment and Disposal Options will be evaluated by this numerical technique which is described and utilized below. Evaluations were completed by members of the Technical Advisor Committee.

5.1 METHODOLOGY

Each of the main factors has been allotted a maximum score which totals 100 points as shown:

Financial 30

Environmental 25

Engineering 20

Social 10

Political 15

100

For any particular project the total score available for each factor can be adjusted to reflect the sensitivities of each issue for that particular project. The following describes the evaluation criteria noted above.



Financial Consideration (30 points)

Capital costs and operating costs were allotted equal weight in the evaluation process. This is realistic since operating costs are borne entirely out of the local governments’ revenues and over time, represent an equal or greater cost to the tax payer than capital costs. In scoring alternatives, the lowest capital and operating cost alternatives are awarded 30 points (15 points each), while other options are scored in proportion to their increased costs above these low costs.

Environmental Considerations (25 points)

The important considerations are the residual impact of the effluent on public health, recreational considerations, lake and river water quality and fish propagation.

Public Health (0-5 points) protects public for exposure to untreated effluent.

Recreational Use (0-7 points) protects water quality to ensure ongoing recreational uses of the lake and river channel.

Water Quality (0-5 points) protects water quality for residences that utilize Skaha Lake as a drinking water source.

Ecosystem Enhancement (0-5 points) provides opportunities for ecosystem enhancement.

Fish Propagation (0-3 points) protects water quality in the river channel and Skaha Lake for spawning and rearing of fish.

For each of these factor the alternative registering the least impact would be awarded the highest score, while the greatest impact would be scored lowest.

Engineering Considerations (20 points)

The suitability of a system for the City of Penticton from an engineering point of view must consider the following factors:

Operational Reliability (0-4 points) refers to the ability of the treatment and disposal scheme to produce consistent effluent quality. Those systems which are quite stable and which demonstrate a low frequency of process or mechanical equipment failure would be awarded the most points.

Expansion Potential (0-4 points) the population served by the facilities will continue to expand beyond the predicted 20-year levels. The systems could readily be expanded beyond their design levels without major expenditures to relocate or which have the least constraints on expansion would receive the most points under this category.



Ease of Operation (0-4 points) those schemes which could be operated with the least continuous attention from operators or which do not require additional operator skills would be scored the highest.

Energy Conservation (0-4 points) those alternatives which require the most energy would be scored lowest since they would have a significant impact on accelerating operational costs and utilizing a finite resource which could be used for other purposes.

Phasing Potential (0-4 points) the ability to phase in capital works and expenditures is important to the financial viability of the projects as the city has a limited amount of capital available. As well, those projects with a high potential for phasing could be scheduled to bring on portions of the facilities as a function of flow increases.

Social Considerations (10 points)

There is a high level of public concern over wastewater management in Penticton because of the importance of water quality to the region.

Public Acceptance (0-3 points) the schemes which can satisfy residents’ concerns the most would receive the highest scores under this category.

Impact on Adjacent Properties (0-5 points) the location of the treatment plant, the visual impact and potential for odours has a significant impact on adjacent developments. The options that impact adjacent properties the least would receive the highest scores.

Future Development (0-2 points) the ability to allow growth is important to the community. Options that allow future development, increased density or redevelopment of property receive the highest score.

Political Considerations (15 points)

The schemes must pass through approval at both the municipal and provincial levels. Availability for grants to help fund the projects is a key consideration.

Senior Government Approval (0-4 points) the MoE has prime responsibility for approving the project and those alternatives which best meet their policy requirements for environmental protection would score the highest. The costs of any projects must be within the total relative magnitude of the problem in comparison with other areas with similar problems in the province.

City of Penticton and Adjacent Communities (0-6 points) the City and its neighbours are concerned that the pollution control facilities are affordable, acceptable to their constituents, allows future growth, and will protect the environment. The alternatives which best fit these criteria would receive the most points.

Ability to Obtain Grants (0-5 points) projects that are most eligible to receive grants from senior levels of government receives the highest marks.



This numerical evaluation will be completed by committee members and the results tabulated.

5.2 EVALUATION OF OPTIONS

Some of the advantages and disadvantages of the Treatment and Disposal options are identified in Table 5.1 and 5.2.

Table 5.1 Treatment Plant Options

Advantages/Disadvantages

Option Advantages Disadvantages

1 – Upgrade Existing

• Least cost option

• Maintains current mode of operation which staff are familiar with

• Provides redundancy in secondary clarification

• Retrofit existing filters so removal not required

• Staging of construction easily achieved

• Could add MBR in future to increase capacity of bioreactor

• Requires ongoing use of primary clarifiers that have limited capabilities and difficult to split flows.

• Requires significant modification to abandoned secondaries for conversion to primary clarifiers

• Requires 7 or 8 primaries so has more mechanical systems to operate

• Flow split to bioreactors will be difficult

• Flows beyond 27 ML/d will require bioreactor addition unless technology changes

• Footprint of plant expands for new clarifiers

• Ongoing use of chlorine for disinfection. Requires dechlorination

2 – New Primaries

• Significant increase in primary clarifier capacity. Tanks will provide good solids removal due to length and depth.

• Large equalization volume available

• Provides redundary in secondary clarification

• Reduced footprint for filters provides space in building for other uses.

• Incorporates UV disinfection, which is safer for operators and the environment.

• Staging of construction easily achieved

• Could add MBR in future to increase capacity of bioreactor

• Primary clarifiers are somewhat longer than typical designs – will require dual mechanisms or conversion to 6 tanks.

• Flows beyond 27 ML/d will require bioreactor addition unless technology changes

• Footprint of plant expands for new clarifiers



3 – MBR • Significant increase in primary clarifier

capacity. Tanks will provide good solids removal due to length and depth.

• Large equalization volume available

• Bioreactor capacity can be expanded beyond 27 ML/d by adding more cassettes to Train 2 or converting Train 1 – ultimate capacity of both trains approximately 32 ml/d

• Does not require additional clarifiers – limits plant footprint – ultimately greater site capacity

• Reduced footprint for filters provides space in building for other uses.

• Incorporates UV disinfection, which is safer for operators and the environment.

• Membranes provide a physical barrier for solids and microorganisms – may permit lower dilution ratio in river channel

• Provides highest ultimate site capacity because of additional bioreactor capacity

• Improved microbiological effluent quality provided by membrane physical barrier

• Requires additional screening units for removal of 1-2mm solids for MBR.

• Primary clarifiers are somewhat longer than typical designs – will require dual mechanisms or conversion to 6 tanks

• Membranes require intense mechanical systems which are costly to purchase, operate and maintain

• Requires additional piping and tankage for DEOX.

• Highest capital and operating cost

• New technology for operators to learn

• Limited suppliers available for equipment

• Use of this option is more costly up front as membranes must be installed soon as secondary clarification close to capacity with no redundary.

Table 5.2 Disposal Options

Advantages/Disadvantages

Option Advantages Disadvantages

D1 – Maintain Existing

• Beneficial reuse of effluent

• Provides additional flow to river to enhance fisheries and aquatic habitat in low flows

• Opportunities for ecosystem enhancement

• Least cost option

• Potential to move outfall location without going to expense of lake outfall

• Potential public perception problem when dilution ratios are reduced during low flows in river channel

• Dilutions will reach regulatory requirement (10:1) at minimum river channel flow (3 m3/sec) within planning horizon

D2 – New Outfall

• Capacity not limited

• Removes effluent from recreational use waterway

• Beneficial reuse of effluent

• Opportunities for ecosystem enhancement

• No enhancement of river flows

• High cost



Utilizing the information presented in this report and various discussions at Technical Advisory Committee Meetings, each member of the TAC was asked to complete an evaluation of each option. Table 5.3 presents the results of these evaluations. A summary of the evaluation is:

Treatment Plant Options

Option 1 – Upgrade Existing 68.5

Option 2 – New Primaries 89.8

Option 3 – MBR 71.3

Disposal Options

D1 – Maintain Existing 76.9

D2 – New Outfall 74.9

Based on this evaluation technique the preferred options are Option 2 - New Primaries and Option D1 – River Channel Outfall.

5.3 PUBLIC CONSULTATION PROGRAM

The goal of public consultation and input is to develop public awareness and understanding of the liquid waste issues and possible solutions available, obtain public feedback as to the preferred option or mix of options, and provide the City of Penticton with direction in their decision making process. The program for public input and participation included the following:

a) Newsletters

Two newsletters were mailed to all residents of the City.

The purpose of the first newsletter (March 2005) was to advise residents that the City was initiating a study to update the 1987 LWMP. The Newsletter provided background information, identified the process for updating the Plan, and requested input from the public during the process.

The second Newsletter, February 2006, updated background information, identified Wastewater issues and options, and provided initial costs for each option. A questionnaire was included with this Newsletter – the Newsletters and Questionnaire are included in Appendix E.

b) Web Site

A project web site was established at the outset of the study (www.pentictonlwmp.com). The web site contained the 1987 Stage 3 Report from the LWMP, provided background information and photos on the project, and had all reports, technical memos, newsletters and questionnaires posted for the public to review.


http://www.pentictonlwmp.com/


#1 UPGRADE EXISTING

#2 NEW PRIMAIRES

#3 MEMBRANE BIOREACTOR

#D1 MAINTAIN EXISTING

#D2 NEW OUTFALL

Financial (30) Capital Cost 15 11.1 13.5 8.8 11.6 8.8 Operating Cost 15 10.8 14.1 10 11.9 10.4Environmental (25) Public Health 5 3.1 3.7 4.5 5.8 4.6 Recreational Use 7 4.3 5.5 5.6 4.2 6.4 Water Quality 5 3.6 4.1 4.7 4.4 4 Ecosystem Enhancement 5 3.2 3.9 3.7 3.9 3 Fish Propagation 3 2.1 3 3.3 2.4 2Engineering (20) Reliability 4 3.1 4.4 3.5 3 3.7 Expansion 4 2.8 3.8 3.8 3 3.4 Ease of Operation 4 2.8 4 1.9 3.3 3.3 Energy Conservation 4 2.9 3.6 1.9 3.4 3 Phasing 4 2.9 3.8 1.9 3.4 2.4Social (10) Public Acceptance 3 1.8 2.8 1.6 1.9 2.4 Impact on Adjacent Properties 5 3.2 4.4 4.2 3.6 3.9 Future Development 2 1.2 1.7 1.5 1.3 1.9Politcial (15) Senior Government Approval 4 2.6 3.7 3.2 2.5 3.5 City and Adjacent Community Approval 6 3.5 5.2 3.2 4.3 4 Grants 5 3.6 4.6 4 3 4.2

TOTALS 100 68.5 89.8 71.3 76.9 74.9

TABLE 5.3OPTION EVALUATION SUMMARY

EVALUATION CRITERIA TOTAL SCORE AVAILABLE

WASTEWATER TREATMENT OPTIONS DISPOSAL OPTIONS



c) Public Meeting

A public meeting was held on March 8, 2006 at the Days Inn. The format of the meeting was an open-house from 5:00pm to 7:00pm, with a presentation by the City, MoE and Stantec Consulting at 7:00pm. The meeting was attended by 30 people and adjourned at approximately 9:00pm. There were no issues or concerns raised by the public at this meeting that were not answered by the presenters with information/data included in this report.

d) Questionnaire

Questionnaires were sent to all residences in Penticton with the February Newsletter. Of the 10,000+ questionnaires sent out approximately 360 have been returned to date. Results of the questionnaire are included in Appendix E. Some of the key responses included:

Question 3 - The City will be upgrading the existing treatment plant to meet growth in the City and replace aging equipment. For upgrading the treatment system what advice would you give the City?

Spend the least (Option 1) 13%

Newer technology, safe, easier but higher cost (Option 2) 51%

Highest level of treatment but more expensive (Option 3) 36%

Question 4 - When the City upgrades the Treatment Plant what do you feel is the most important issue to deal with from your perspective?

Top 3 Responses were:

Protect Water Quality

Long Term Operating Costs

Reliability

Question 5 - Since the Advanced Wastewater Treatment Plant was constructed in 1991, the Okanagan River channel and Skaha Lake have experienced significant improvements in water quality. How important is water quality to you and your family?

Extremely Important 71%

Very Important 15%

Important 12%

Not Important 2%



The cost of wastewater treatment in Penticton is currently less than Kelowna or Vernon but provides the same high level of treatment. How much more are you willing to spend to maintain or continue to improve water quality in the River Channel and Lakes?

No increase 17%

0 - $50 29%

$50 - $100 36%

$100 - $150 18%

Question 6 - Effluent Disposal – The current treated effluent disposal system consists of effluent irrigation on the Penticton Golf and Country Club, Kings and Queens Park, and an outfall to the Okanagan River Channel. The river channel discharge has been in service for over 40 years. The effluent quality is a very high standard that is outlet to the river channel and has minimal impact on the water quality. What would be your advice to the City as a minimum dilution ratio (parts river flow to parts effluent flow) that you would accept. The minimum dilution according to environmental regulations is 10:1 (10 parts river flow to 1 part effluent)

Winter Months

Not Important 7%

10:1 28%

20:1 26%

30:1 16%

50:1 18%

Summer Months

Not Important 4%

10:1 15%

20:1 21%

30:1 20%

50:1 40%



Dilution ratios in June 2004 were as low as 19:1 due to low water levels in the River Channel. Typically dilutions in the Summer months are, however, generally approximately 60:1. At what dilution ratio do you think the City should consider a deep lake outfall to Skaha Lake?

Not acceptable option 35%

10:1 10%

20:1 16%

50:1 24%

100:1 15%

A deep lake outfall will cost in the order of $5,000,000 to construct ($50 per year per household). Is a deep lake outfall a preferred option versus the river outfall. Note - prior to consideration of a deep lake outfall, environmental impact studies would be completed to determine the impact the effluent would have on Skaha Lake and water intakes located in Skaha Lake.

Yes 43%

No 57%

How much per year would you be willing to add to your taxes to pay for a deep lake outfall if you would prefer this disposal option?

Don’t want it 59%

0 - $25 8%

$25 - $50 13%

$50 - $75 10%

$75 - $100 5%

> $100 5%

If the City constructed an ultra fine membrane filtration plant that treats the effluent to near drinking water standards, would it change your answers on the above questions? (Ultra fine filtration adds $7,000,000 to the cost of the treatment plant - $60 per year per household)

Yes 42%

No 58%



Some of the common comments received included:

• Have already replaced fixtures with low water use ones

• Low water use fixtures prevent proper flushing

• Odours from treatment plant in summer

• Protect water quality in river channel

• Taxes high already, can’t afford more



6.0 CONCLUSIONS AND RECOMMENDATIONS

6.1 CONCLUSIONS

The following conclusions are based on the work completed in preparation of this report, input from the Technical Advisory Committee and the public.

• The City of Penticton’s Advanced Wastewater Treatment Plant is a well-run facility that produces a high quality effluent that meets or exceeds all requirements of the Operating Certificate.

• The effluent produced by the plant has had a positive impact on the Okanagan River Channel and Skaha Lake. Since the plant was upgraded in 1991, there have been noticeable improvements in water clarity and a reduction in phosphorus levels in Skaha Lake.

• The per capital wastewater flows are above what would be expected for an Okanagan municipality. The City must undertake source control measures to extend the life of the treatment works, particularly the bioreactor to 27 ML/d or higher flows.

• Of the 150 km of gravity sewermains and forcemains, only 4 km are predicted to experience peak flows in excess of 80% of their pipe full flow capacity. Upgrading of some sections of pipeline will be required as growth occurs.

• Each unit process at the treatment plant was evaluated for capacity and equipment condition. There are a number of processes that will need to be upgraded within the next 5 years.

• The discharge of treated effluent to the Okanagan River Channel meets all regulatory requirements now and well into the future. The risk analysis completed by BC Centre for Disease Control states there are limited risks associated with effluent discharge to the channel as long as the effluent meets the Canadian Recreational Water guidelines.

• Storm water runoff from the City is having an impact on water quality in the Okanagan River Channel and possibly other receiving streams.

• The Option for upgrading the wastewater treatment plant that received the highest score in the evaluation was Option 2 – New Primaries. This is not the least expensive option, but does provide the City with the best long-term value. There is the potential in the future to add membranes to the bioreactor which could add capacity without having to expand the plant.



• Option D1 – Maintain Existing received the highest score in the evaluation of disposal options. The outfall to the river channel can therefore be maintained in its current configuration until at least year 2019 (±). Reductions in per capita flow and additional effluent irrigation can extend this time period. Note this date is based on absolute minimum river channel flows – using statistical analysis of river flows would extend the discharge beyond this date. Moving the discharge location downstream of the recreational user area would also extend the date when alternate disposal systems would be needed.

• The current production of Class A Compost from the biosolids is a beneficial reuse.

6.2 RECOMMENDATIONS

The following recommendations are provided to the City of Penticton based on the results of this LWMP update.

• The City should implement a source control program to reduce per capita wastewater flows. This program should include monitoring of flows in the collection systems and determining sources of I/I and then undertaking projects to reduce them. It should also include programs to encourage the residents of Penticton to reduce their wastewater flows.

• Recommendations provided in the sewer collection study which are briefly outlined in this document be implemented.

• The City accept Option 2 – New Primaries as the selected treatment option and proceed with preliminary engineering design for Option 2 – New Primaries and then design and construction of priorized Category A Unit Processes. The Stage 3 Report will identify an implementation plan for this work.

• The City accept Option D1 – Maintain Existing for the selected disposal option.

• The City revise its monitoring and testing program of the effluent and Okanagan River Channel as follows:

- In the effluent and river channel, measure E. coli as the indicator mechanism of fecal contamination. Continue with monitoring fecal coliforms for a transition period until such time as Health Canada and IHA officially adopt E.coli as a water use standard.

- Relocate the location for sampling of river channel water in the Operation Certificate from 2.4 km upstream of the outfall to 15 metres upstream of the outfall. Continue with monitoring at the 2.4 km upstream location as this will provide information on storm water impacts on the river channel.



- Increase the frequency of monitoring for E. coli during summer months when recreational uses are occurring in the channel.

- If changes or upsets occur in the treatment process, increase the frequency of testing of the effluent and downstream river channel location.

• Revise the permit requirements for effluent disinfection discharged to the river channel to 2.2 MPN/100 ml for E. coli during recreational use of the river channel (June through September). During the remainder of the year, the permit level would be 50 MPN/100 ml however strive to maintain 2.2 MPN/100 ml all year long.

• Increase the amount of effluent irrigation. This will reduce the amount of effluent discharged to the river channel and reduce the demand for potable water for irrigation purposes. Extend effluent irrigation pipelines to the south end of the City. When sizing the pipelines, analyze the potential for relocation of the outfall to beyond the Highway 97 bridge and recreational use area.

• After completion of baseline inventory studies of the existing ecosystem, undertake a pilot testing program for discharging effluent to an oxbow.

• Maintain the current production of Class A compact from the plant’s biosolids.

• Design and construct a septage receiving facility at the Wastewater Treatment Plant. The facility should be designed in 2006 and constructed in 2007.

• Complete the Master Drainage Plan and implement the goals and objectives identified in this plan. The first step will be to undertake a program of water quality monitoring to identify priority areas of concern and then proceed with the development of Integrated Storm Water Management Plans for the priority areas. One of the areas to focus initial work may be the Okanagan River Channel due to its recreational use. Undertake a storm water treatment pilot program on one of the oxbows, possibly in combination with discharge of effluent noted above.

• Extend sewer collection systems to areas that are still using onsite disposal systems.

• Approach the Ministry of Environment to modify the total nitrogen levels in the effluent from 6.0 mg/l to 8.0 mg/l. The 8.0 mg/l would be made up of 6.0 mg/l nitrate, 1.0 mg/l ammonia, and 1.0 mg/l buffer.

• Update sewer use bylaws to include septage disposal at the treatment plant. Examine rate structures, conservation measures and other source control methods for reducing flows and loads on the wastewater treatment facility.

• Update subdivision servicing bylaws to incorporate source control measures and Best Management Practices for storm water management.



• Maintain the current level of operational efficiency at the Wastewater Treatment Plant so that effluent quality continues to meet the high standards achieved over the last 15 years.


Documents

CITY OF PENTICTON Liquid Waste Management Plan … Stage 2 pages 89-113.pdf · Liquid Waste Management Plan Stage 2 ... Membrane Bioreactor ... CITY OF PENTICTON Liquid Waste Management