Westside Regional WWTP Service Review. Regional District of Central Okanagan

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1 Westside Regional WWTP Service Review Regional District of Central Okanagan

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3 Westside Regional WWTP Service Review i Contents Executive Summary Introduction Report Objectives List of Abbreviations and Acronyms References Information Review Analysis of Treatment Processes Projected Wastewater Flows Influent Screens Vortex Grit Chambers Primary Clarifiers Bioreactors Secondary Clarifiers Tertiary Filters UV Disinfection Outfall and Effluent Pump Station Waste Solids Thickening and Dewatering Primary Sludge Fermenters Process Reliability Effluent and Residual Quality Energy Efficiency Cost Site Life Expectancy Assessment Current Site Potential Future Sites Distributed or Satellite Plants Cost of Service Review Operations Asset Management Overhead Recommendations Appendix A: Potential Future Site Figures... 36

4 Westside Regional WWTP Service Review ii LIST OF TABLES Table E-1: Expansion Costs Beyond Stage 4 (to projected 2065 Wastewater Flows) E-2 Table 1-1: List of Background Documents... 6 Table 2-1: Westside Regional WWTP Effluent Criteria... 7 Table 3-1: Total Peak Hydraulic Capacity of Existing Unit Process... 8 Table 3-2: Fermenter Capacity Assessment Table 3-3: BC Wastewater Regulation Reliability Requirements for Wastewater Facilities Table 3-4: Expansion Costs Beyond Stage 4 (to Projected 2065 Wastewater Flows) Table 4-1: Potential New Options Table 4-2: GIS Search Constraints Table 4-3: RDCO West Side Trunk Sewer Table 5-1: Westside Regional WWTP Funding (Neilson-Welch, 2010; RDCO, 2015) Table 5-2: Overhead Costs Charged to the Westside Regional WWTP Table 5-3: 2015 Budgeted Expenses for the Westside Regional WWTP Table 5-4: WWTP Overhead Costs LIST OF FIGURES Figure 3-1 Long range (50 year) wastewater flow projections... 8 Figure 3-2 Final Effluent Annual Average TN and TP Figure 3-3 Daily Final Effluent Nitrogen Species and Temperature ( ) Figure Westside Regional WWTP GPS-X Process Schematic for Stage Figure 3-5 Seasonal VFA and PE Soluble COD trend Figure 5-1 O&M Cost Summary for Westside Regional, Penticton, and Whistler WWTPs... 31

5 Westside Regional WWTP Service Review E-1 Executive Summary The Regional District of Central Okanagan (RDCO) retained Opus DaytonKnight Consultants Ltd. (Opus) to evaluate the most fundamental aspects of the Westside Regional Wastewater Treatment Plant (WWTP) for a 50 year planning horizon of The high-level objectives included: a. Evaluate the current wastewater treatment process at the Westside Regional WWTP to identify opportunities for improvement in the current to long term (30 to 50 years) through process or operational change; b. Provide the life expectancy of the current site and review potential new sites that should be considered after the current site has reached maximum capacity or a critical social or environmental threshold that prevents future use or expansion (e.g. odour); and, c. Complete a cost of service review to identify if there are opportunities to reduce costs and improve service through changes in process, operation, management, or governance. With the current unit processes, the plant has an average day flow treatment capacity of 16.8 MLD. The hydraulic structures have an instantaneous peak flow capacity of 33.6 MLD. The treatment capacity of the existing site (based on expansion of the existing unit processes) is limited to the projected average day wastewater flows of 22.4 MLD in Due to the physical constraints of the existing site, the limiting processes are the bioreactors and the primary and secondary clarifiers (outfall and effluent pump station notwithstanding). It appears that all of the other processes can be expanded on the existing site to handle the projected average day wastewater flows of 36.6 MLD in It should be emphasized that the timeline for reaching the capacity constraint is dependent on the actual growth of the sewerage area and service population. As a consequence, the RDCO should review the wastewater flow projections on a regular basis (3 to 5 years), in conjunction with development planning projections for each of the major stakeholders. Our assessment of the Westside Regional WWTP was focused on alternative processes to increase the treatment capacity of the BNR process and the primary and secondary clarifiers. Our assessment also included a high-level review of potential future sites and a cost-of-service review. Primary Treatment The existing configuration of the site allows for up to 7 primary clarifiers. Primary clarifier performance and capacity could be increased if needed through chemically enhanced primary treatment (CEPT). CEPT decreases the settling time which effectively reduces the required area of the primary clarifiers. Chemical addition could be selectively used during periods of peak flows and loading, to minimize costs, although chemical use would increase as flows approached design capacity.

6 Westside Regional WWTP Service Review E-2 CEPT would allow the Westside Regional WWTP to meet the 2065 primary servicing requirements on the existing site using the 7 primary clarifiers currently planned for the Stage 4 upgrade with selective chemical dosing during peak flows and loads. Bioreactors The existing bioreactors provide a treatment capacity of 33.6 MLD, which meets the Stage 3 design criteria. The physical constraints of the existing site only allow for an additional 2 bioreactors which would bring the total biological nutrient removal (BNR) capacity to 44.8 MLD. An alternative biological nutrient removal process is therefore required for the existing site to treat the projected wastewater flows of One option is to incorporate an integrated fixed film activated sludge (IFAS) into the existing continuous flow process. A second option is to convert the WWTP to a granular sludge process. A third option is to retrofit the bioreactors with a Bio-Mag system. All three processes would reduce the footprint required for biological treatment, and allow treatment of the additional wastewater flows to If the bioreactors are successfully converted to a different process using available technology such as IFAS, the site can meet the 2065 treatment capacity requirements within the existing site constraints. This will require increased chemical use to meet the effluent discharge criteria (i.e. methanol for denitrification and alum or similar for removal of residual phosphorus). Alternatively, it is likely that the ongoing development of other alternatives such the granular sludge process will allow expansion within the existing bioreactor footprint with less or possibly no chemical use. Secondary Clarifiers The secondary clarifiers will be the remaining bottleneck that limits the current site to the projected 2045 wastewater flows. Two alternatives for expanding this process step beyond 2045 would be expansion of the site into the adjoining nursery to allow future addition of four more secondary clarifiers, or replacement of some of the secondary clarifiers with an alternative solids separation process such as dissolved air flotation (DAF) or Actiflo. Of note, if the bioreactors are converted to a granular sludge process the need for additional, or possibly all, secondary clarifiers is eliminated. The granular sludge process could in effect increase the overall site capacity by 40% to 50%. Cost Summary The high-level cost estimate of converting processes at the existing Westside Regional WWTP to service the projected 2065 wastewater flows is $23.25 million as detailed in Table E-1 below.

7 Westside Regional WWTP Service Review E-3 Table E-1: Expansion Costs Beyond Stage 4 (to Projected 2065 Wastewater Flows) Item Capital Cost Primary Treatment 3 rd influent screen $400,000 3 rd and 4 th vortex grit chambers $600,000 4 th, 5 th, 6 th, and 7 th Primary Clarifiers NO ADDITIONAL COST Implement CEPT $500,000 Secondary Treatment Conventional biological process to IFAS $6,000,000 2 additional secondary clarifiers, flow split and piping NO ADDITIONAL COST 2 DAF units to supplement secondary clarifiers $1,500,000 3 rd Fermenter $500,000 Tertiary Treatment Twin UV disinfection $1,000,000 Outfall and Effluent Pump Station Improvements $2,000,000 General Site Requirements Expand Odour Control $1,000,000 General Electric and Civil Upgrades $2,000,000 Subtotal $15,500,000 Contingency Allowance, 50 percent $7,750,000 Total $23,250,000 The cost of second tertiary treatment plant located in a major development node (e.g. Westbank First Nation IR10 or the District of Peachland) designed for an average day flow of 14,200 m 3 is estimated at $50 million to $60 million, not including modifications to the conveyance system, land purchase or community consultation (existing WWTP to Stage 4 only). The long term operation and maintenance costs will be significantly greater for operation of two plants compared to one. Although the unit processes would be smaller at the two plants, the same sequence of processes would be required as at a single plant (e.g., headworks, primary treatment, biological treatment, solids handling, etc.). Therefore it is apparent that a single facility is more cost-effective, provided that the site space is sufficient to serve the build-out population, and the option of expanding the existing site into the adjacent nursery should be revisited if feasible. However, identification of an alternate site can still be beneficial for the long-term future (e.g. for a dedicated solids processing facility with reserve recovery). Potential Future Sites Potential new sites were investigated using a desktop GIS spatial analysis searching for all possible sites meeting the following specific criteria: within reasonable distance to the existing trunk collection system, distance from odour receptors, proximity to lake for outfall and highway for biosolids hauling, minimum footprint size, and acceptable site topography. From this search, 3 sites met the criteria within West Kelowna land zoned as agricultural. While one site meeting the GIS search criteria within Peachland was eliminated as a regional facility, it could potentially function as a Peachland only satellite facility albeit with a severe public impact. A second possible satellite plant could be considered with IR 9 based primarily on the significant growth projected in that area. The existence of their drinking water intake near the limited outfall options makes this option equally unfavorable. In summary, there are sites

8 Westside Regional WWTP Service Review E-4 available for consideration but potential drawbacks appear to outweigh the associated costs of a new WWTP combined with costs for changes to the collection system. Cost of Service Review In order to assess operation and maintenance (O&M) costs for the Westside Regional WWTP, two other similar BNR type plants were compared; Penticton and Whistler. The WWTP are similar in liquid and biosolids treatment, are relatively new, and are similar in size. Our highlevel review found that the Westside Regional WWTP has comparable O&M costs to that of Penticton and Whistler when compared on a dollars per cubic meter of treated wastewater. The Westside Regional WWTP has an estimated average treatment cost of $0.56 per cubic meter treated while Penticton and Whistler are $0.54 per cubic meter and $0.55 per cubic meter, respectively. It is difficult to compare overhead costs between WWTPs. The previous recommendation to the regional board to conduct a Value for Money audit of the overhead charges and services provided by the RDCO to the Westside Regional WWTP is reiterated. Such an audit would allow for a formal documentation of the overhead services provided by the RDCO to the Westside Regional WWTP. Recommendations Opportunities for expanding site capacity that should be evaluated in a future feasibility study include the following: conversion of biological process to IFAS or other low-footprint BNR technology to treat 2065 wastewater flows; replacement of at least some of the secondary clarifiers with an alternate solids separation technology such as DAF to treat the projected 2065 wastewater flows; develop a plan for beneficial use of solid residuals produced at the WWTP; Study to review DCCs and reserves to ensure these are adequate going forward; use of CEPT during periods of high flow and loads to allow 7 primary clarifiers to treat the projected 2065 wastewater flows; use of 7 primary clarifiers without chemical addition to treat the projected 2065 wastewater flows, with the resulting increased loading in the primary clarifier overflow being accommodated by the biological and secondary solids separation processes; use of solids digestion/resource recovery, possibly at an alternative site; and, conduct a Value for Money audit to confirm the overhead costs charged to the Westside Regional WWTP.

9 Westside Regional WWTP Service Review 5 1 Introduction The Regional District of Central Okanagan (RDCO) retained. (Opus) to evaluate the most fundamental aspects of the Westside Regional Wastewater Treatment Plant (WWTP). The outcomes from this evaluation of the site, processes, and cost of service are intended to form the basis for a later and more detailed Master Plan. 1.1 Report Objectives The high-level objectives of this report include: a. Evaluate the current wastewater treatment process at the Westside Regional WWTP to identify opportunities for improvement in the current to long term (30 to 50 years) through process or operational change; b. Provide the life expectancy of the current site and review potential new sites that should be considered after the current site has reached maximum capacity or a critical social or environmental threshold that prevents future use or expansion (e.g. odour); and c. Complete a cost of service review to identify if there are opportunities to reduce costs and improve service through changes in process, operation, management, or governance. 1.2 List of Abbreviations and Acronyms BNR BOD CEPT COD MOE MDD mg/l MLD MPN N OC P RDCO TSS WWTP Biological nutrient removal Biological Oxygen Demand Chemically enhanced primary treatment Chemical Oxygen Demand BC Ministry of Environment Maximum Day Demand milligrams per litre mega litres per day Most Probable Number Nitrogen Operating Certificate Phosphorus Regional District of Central Okanagan Total Suspended Solids Wastewater Treatment Plant 1.3 References The RDCO provided previous reports, drawings, financial information, and GIS data to assist in the evaluation of the Westside Regional WWTP. Opus also obtained financial information from the City of Penticton and the Resort Municipality of Whistler, both of which operate biological nutrient removal processes from the wastewater from a similar population size. The documents referenced are listed in Table 1-1.

10 Westside Regional WWTP Service Review 6 Table 1-1: List of Background Documents Title/Description Author/Source Year Stage 2 Bioreactor Drawings Reid Crowther 1993 Stage 2 Upgrades Pre-Design Report AECOM 2010 Service Funding and Governance Neilson-Welch 2010 Stage 3 Upgrades Issued for Construction Drawings AECOM 2010 Stage 3 Upgrade Completion Report RDCO 2012 Odour Mitigation and Foul Air Assessment Study Letter Report AECOM 2013 Final 2013 CORD West Kelowna Odour Survey Discovery Research 2013 Regional Growth Strategy Schedule A RDCO 2013 District of West Kelowna Schedule B Zoning Bylaw Map DWK 2013 National Water & Wastewater Benchmarking Initiative Public AECOM 2013 Report Annual Report 2014 RDCO 2014 Grant Application for Assessment of Odor and Land Application RDCO 2014 Impacts of Disposal of Westside Municipal Biosolids Casa Loma Sewage Pump Station Proposed Design AECOM 2014 Modification Biofilter Retrofits CH2MHILL 2014 Treated Municipal Wastewater Irrigation Feasibility SUMMIT 2015 Assessment Operating Information for the WWTP RDCO 2014 City of Penticton WWTP Financial Information Penticton 2014 Resort Municipality of Whistler WWTP Financial Information Whistler 2014 Financial Information for the WWTP and Trunk System RDCO 2014/ Financial Plan RDCO 2015 Stakeholder Select Committee Meeting RDCO 2015/02/18 City of West Kelowna GIS Data West Kelowna 2015 District of Peachland GIS Data RDCO 2015 Westbank First Nation GIS Data RDCO Information Review The Westside Regional WWTP utilizes a biological nutrient removal (BNR) process, aluminum sulphate for supplemental phosphorus removal, Aqua Cloth Media filters, and an ultraviolet disinfection system to provide a high quality final effluent for discharge to Okanagan Lake. The Westside Regional WWTP is located on Gellatly Road in the West Kelowna and is operated by the RDCO. In addition to the District of West Kelowna, the WWTP services development in the District of Peachland, Westbank First Nation Reserve 9 and 10 and RDCO. In 1994, the WWTP s BNR process was converted from the University of Capetown (UCT) process, to the Westbank process, in conjunction with the District s Stage 1 Expansion, as part of a 4-staged upgrade plan to maximize the utilization of the plant footprint. Each of the 4 stages was designed to provide an additional average day flow capacity of 5,600 m 3 /d. Stage 5 is planned as an enhanced process technology. In 2010, design and construction of the Stage 3 upgrades was commissioned by RDCO, bringing the average day flow capacity to 16,800 m 3 /d.

11 Westside Regional WWTP Service Review 7 The Westside Regional WWTP operates under BC Ministry of Environment (MOE), Operational Certificate (OC) #PE The OC specifies effluent and operating criteria for the WWTP (Table 2-1). The effluent total phosphorus limit was decreased from 0.25 mg P/L to 0.20 mg P/L on January 1, Table 2-1: Westside Regional WWTP Effluent Criteria Parameter Effluent Limit Biological Oxygen Demand (BOD5) <10 mg/l Total Suspended Solids (TSS) <10 mg/l Total Phosphorus (TP) <0.20 mg P/L (annual average) Total Nitrogen (TN) <6 mg N/L (annual average) Fecal Coliform <50/100mL MPN The RDCO Regional Growth Strategy (Bylaw No. 1336, 2013) projects a 1.8% (linear) annual population growth in the Region by Historically, the population growth peaked in the 1990 s at 4.0% and slowed to 2.1% from 2000 to The annual average wastewater flow to the Westside Regional WWTP has grown at a much higher rate from 1990 to 2014, but this is a reflection of growth in the sewer collection system to service existing housing. Since most of the existing single family housing has been serviced, the expectation is that growth in wastewater flow will converge with population growth in the near future. 3 Analysis of Treatment Processes Our review of Westside Regional WWTP was based on an assessment of the current and available treatment capacity using the existing unit processes until the 50 year planning horizon of The physical site constraints limit the expansion of the existing BNR process and secondary clarifiers. In undertaking this task we developed a model of the current BNR process and benchmarked the plant against similar BNR plant performance and loading criteria. Different modelling scenarios were developed to see what processes options could expand the plant capacity within the current plant site footprint. The development of plant options and review of the current plant performance was done in collaboration with Dr. James Barnard, who acted as senior technical advisor for the project team. 3.1 Projected Wastewater Flows For the purposes of projecting wastewater flow rates to the Westside Regional WWTP, a compounded 2.5% growth rate was assumed (Figure 3-1). The assumed 2.5% compounded growth rate is conservative (higher) compared to the Regional Growth Strategy population projection. The higher growth rate accounts for the fact that wastewater will outpace population growth over the short term, and it allows for the planned growth in IR 10 identified as part of the Casa Loma Sewage Pump Station, Proposed Design Modifications (AECOM Technical Memorandum). The 2.5% compound rate translates to a 7.2% annualized linear growth rate over the 50 year planning timeline and is similar to the Medium Growth Rate scenario in the 2010 Stage 3 WWTP Pre-design Report (AECOM). Projecting wastewater flows at a 2.5% annual growth rate means that the Stage 3 average day flow capacity of 16,800 m 3 /d could be reached by the year The planned Stage 4 average day flow

12 Westside Regional WWTP Service Review 8 capacity 22,400 m 3 /d would be reached by the year The average day wastewater flows in the design horizon year of 2065 would be 36,600 m 3 /d. The wastewater flow projections are approximations, and the actual year in which the Stage 3 and Stage 4 plant capacity will be reached depends upon population growth, water use practices/water conservation, and additional inflow and infiltration from sewer deterioration. 40,000 35,000 36,600 m 3 /day Average Day Flow (m3/d) 30,000 25,000 20,000 15,000 10,000 5,000 16,800 m 3 /day 22,400 m 3 /day Historical Data Projected Flow Design ADF 0 Figure 3-1 Long range (50 year) wastewater flow projections The capacity of major unit processes were evaluated to identify potential bottlenecks in the system; the total installed peak hydraulic capacity (not average day flow capacity) of each unit process is provided in Table 3-1. As shown, the existing site is limited by the capacity of the bioreactors and the secondary clarifiers. In the proposed configuration for the Stage 4 expansion the total peak hydraulic capacity of the existing site is about 44.8MLD which is projected to occur in the year 2045 at the 2.5% compound growth rate. Table 3-1: Total Peak Hydraulic Capacity of Existing Unit Process Unit Process Unit Capacity (MLD) Units Stage 3 Total Capacity (MLD) Projected Year of Capacity Site Build-out with Existing Unit Processes at 2.5% Annual Growth Total Projected Year Units Capacity of Capacity (MLD) Influent Screens Vortex Grit Chambers b Primary Clarifiers a Bioreactors (Stage 1-3) Secondary Clarifiers Tertiary Filters UV Disinfection b Overall Plant Notes: a) There are currently only 3 primary clarifiers. The addition of a fourth primary clarifier would add an additional 8.4 MLD of hydraulic capacity bringing the total installed capacity of 33.6 MLD. b) Assumes that space is available for additional units.

13 Westside Regional WWTP Service Review 9 Each of the unit processes listed in Table 3-1 are discussed in more detail below. The costs presented are the incremental costs for expanding the plant after the Stage 4 upgrade is completed to service the projected design horizon wastewater flows in Influent Screens The influent screening building was designed to split flow into three channels. Perforated plate type mechanical screens are installed on two of the three channels to allow the third channel to service as an emergency by-pass. The peak flow capacity of the two existing influent screens is 72 MLD, which is close to the estimated peak flows 73.1 MLD in The existing hydraulic capacity should therefore be sufficient until the design horizon of 2065 and allow one channel to remain as an emergency bypass. However, flow projections should be reviewed regularly to determine if a third screen will be required. In any case, a third (redundant) screen may be desired. Cost estimate (2015 dollars): $400,000 for a third screen adopted from AECOM, Vortex Grit Chambers There are currently two vortex grit chambers. The peak hour capacity of each vortex grit chamber is 26.4 MLD which currently allows one to operate while the other provides redundancy. A third vortex grit chamber will be required as peak wastewater flows approach 33.6 MLD. The third vortex grit chamber will provide for peak flows until the design horizon of A fourth will be required to provide for redundancy. Cost estimate (2015 dollars): $300,000 for each grit chamber, for a total of $600,000 adopted from AECOM, Primary Clarifiers The three existing primary clarifiers are designed for a total peak hourly flow of 25.2 MLD. A fourth primary clarifier is needed to bring the hydraulic capacity up to the Stage 3 design flows of 33.6 MLD. The existing configuration of the site allows for up to 7 primary clarifiers. Primary clarifier performance and capacity could be increased if needed through chemically enhanced primary treatment (CEPT). Chemical addition could be selectively used during periods of peak flows and loading, to minimize costs, although chemical use would increase as flows approached design capacity. On-site testing would be required to determine the optimum coagulant and dose. CEPT decreases the settling time, which effectively reduces the required area of the primary clarifiers. The additional of alum (and possibly polymer) through this process has the added advantage of removing dissolved phosphorus which would provide a factor of safety if the biological treatment process is upgraded to Integrate Fixed-film Activated Sludge (IFAS) technology (see Section 3.5.4). It should be noted that the addition of alum at the head end of the plant will significantly reduce the concentration of phosphorus reaching the biological process and this could impact biological phosphorus removal. Addition of coagulating chemicals may have an (unknown) impact on the soluble and particulate

14 Westside Regional WWTP Service Review 10 fractions of COD, N and P in the primary tank overflow, and it would also increase the amount of primary sludge available for fermentation. Clarifier overflow rates and BOD/TSS removal increase with implementation of CEPT. With CEPT, BOD removal rates can be between 50% to 80% with overflow rates between 70 m 3 /m 2 /d and 30 m 3 /m 2 /d, respectively. This compares to conventional primary settling, which achieves 25% to 40% BOD reduction for overflow rates between 50 m 3 /m 2 /d and 30 m 3 /m 2 /d, respectively. Consequently, primary clarifier area can be reduced by over 50% with the addition of CEPT, with an increase in BOD removal from 40% to 50%. This is because overflow rates can be greater when precipitation is chemically enhanced. Conventional primary settling will remove 50% to 70% of TSS, while CEPT will remove 80% to 90% of TSS. On a dry weight basis, this will result in between 100 kg/d to 140 kg/d of solids removed in the conventional process. With the CEPT process, an assumed alum dose of 10 mg/l would produce about 43 kg/d of aluminum hydroxide precipitate along with 160 kg/d to 180 kg/d of dry solids. Assuming a moisture content of about 95%, and a specific gravity of 1.05, this results in wet volumes of between 2.1 m 3 /d to 2.9 m 3 /d for a conventional process, and 4.3 m 3 /d to 4.7 m 3 /d for the CEPT process. The CEPT process has increased sludge primary yields because more solids are being removed and coagulant precipitate is added to that volume. It is important to note that enhanced removal of primary solids using CEPT results in lower solids production downstream in the biological treatment process (i.e. lower yield of waste activated sludge), as well as a lower aeration requirement. Advantages of CEPT Reduces aeration requirements in the biological process, and reduces the amount of waste biological sludge produced. Alum stabilizes P removal. Reduces required primary clarifier area. Additional primary sludge available for fermentation. Disadvantages of CEPT Control issue of leaving enough P for biological treatment but low enough to meet effluent standards. Competing reactions for hydroxides can decrease dose efficiency. Removes alkalinity before nitrification process, which can result in low ph levels that inhibit nitrification. Removes BOD in the primary tanks that could have been used downstream for denitrification. Can result in larger anoxic tanks or an increased need for methanol for nitrogen removal. Potential impacts on performance of biological process due to changes in soluble and particulate functions of COD, N and P. Does not remove polyphosphates which will be converted to orthophosphate in the bioprocess. CEPT would allow the Westside Regional WWTP to meet the 2065 primary servicing requirements on the existing site using the 7 primary clarifiers currently planned for the Stage 4 upgrade with selective chemical dosing during peak flows and loads. Cost estimate (2015 dollars): Capital cost of implementing CEPT is low (chemical storage and injection facilities) allow $500,000.

15 Westside Regional WWTP Service Review 11 Additional Sludge Handling Costs: Requires more detailed investigation estimated at 10% to 20% increase in overall waste solids during periods when CEPT is in use. 3.5 Bioreactors The existing bioreactors provide a capacity of 33.6 MLD, which meets the Stage 3 design criteria. Additional bioreactors and/or an alternative biological nutrient removal process can be used to accommodate the 73.1 MLD peak flows in Under the current BNR process upgrade plan, the projected build-out of the site will occur when the Stage 4 upgrades are complete. As discussed in Section 2, based on the assumed compound growth rate of 2.5% the Stage 4 capacity could be reached by the year It should be emphasized that the timeline for reaching the capacity constraint is dependent on the actual growth of the sewerage area and service population. As a consequence, the RDCO should review the wastewater flow projections on a regular basis (3 to 5 years), in conjunction with development planning projections for each of the major stakeholders Existing Process Characterization Historical data and annual reports provided by WWTP staff were reviewed, to characterize existing treatment and identify any operational issues. The annual average effluent TP criteria has been met even at the more stringent 0.20 mg P/L standard implemented on January 1, 2014 (Figure 3-2). However, in recent years the annual average effluent TN has exceeded OC objectives. A closer examination of the measured effluent nitrogen data was made to assess the process operation and provide an explanation of the excursions. Figure 3-2 Final Effluent Annual Average TN and TP Total Phosphorus Concentration (mg/l) Total Nitrogen Concentration (mg/l) Average of Total Phosphorus Final Effluent Average of Total Nitrogen Final Effluent

16 Westside Regional WWTP Service Review 12 Figure 3-3 depicts the measured final effluent nitrogen species (TN, ammonia and nitrate/nitrite) alongside effluent temperature for 2013 to Prior to 2014, final effluent TN excursions above the limit of 6.0 mg N/L were associated with elevated nitrate concentrations. This suggests that denitrification (i.e., the part of the biological process by which nitrate is converted to inert nitrogen gas) was not operating efficiently. Through the latter part of 2013, process improvements appear to have significantly improved denitrification. Figure 3-3 Daily Final Effluent Nitrogen Species and Temperature ( ) Nitrogen Concentration (mg N/L) Jan 31 Jan 02 Mar 01 Apr 01 May 31 May 30 Jun 30 Jul 29 Aug 28 Sep 28 Oct 27 Nov 27 Dec 26 Jan 25 Feb 27 Mar 26 Apr 26 May 25 Jun 25 Jul 24 Aug 23 Sep 23 Oct 22 Nov 22 Dec 27 Jan 26 Feb 28 Mar 27 Apr 27 May 26 Jun 26 Jul 25 Aug 24 Sep Ammonia Nitrate /Nitrite Total Nitrogen FE Temperature Temperature ( C) During the March/April period of 2014 and 2015, the WWTP experienced a loss of nitrification efficiency, which caused the effluent ammonia to increase to above 12 mg N/L. The short-term nitrification losses were significant events which for 2014 was the principle cause for the WWTP not meeting its annual average effluent nitrogen objective. A variety of factors may have contributed to the loss of nitrification capacity, and these were investigated as part of this assessment. The nitrification inhibition events of 2014 and 2015 appear to be both associated with seasonal low wastewater temperatures (Figure 3-3). As wastewater temperature decreases, the activity of bacteria that perform the nitrification function also decreases. As a consequence, for the same population and loading, lower wastewater temperatures will result in decreased ammonia oxidation rates. The loss of activity can be mitigated by maintaining a higher sludge retention time (SRT) during low temperature periods by lowering the wasting rate. The longer SRT allows a larger nitrifier bacteria population to grow and offset the decrease in activity.

17 Westside Regional WWTP Service Review 13 The steep loss in nitrification capacity for both the 2014 and 2015 events was preceded by annual low wastewater temperature. To compensate for an increasing effluent ammonia as measured by the weekly average, operational protocol specifies that sludge wasting be decreased by 10% to allow for an increase in SRT. Under this protocol, the SRT is assessed every Wednesday when nutrient data are available. Under normal circumstances, this is an effective approach for controlling effluent nitrogen. However, for the 2015 event it appears that the effluent ammonia began to rapidly increase in the days between Wednesday, February 25 and Wednesday, March 4, when manual SRT adjustments would typically be assessed. On February 25, the average effluent ammonia concentration was 0.57 mg/l, suggesting no change under the existing protocol. On March 4, the weekly effluent ammonia concentration was 2.51 mg/l, indicating a need to decrease wasting. A rapid increase in effluent ammonia can indicate a toxic substance entering the treatment plant which standard operating procedure (SOP) dictates an increase in wasting. A further complication of the process at the time was the availability of sludge storage and hauling capacity. Through the winter, the ability to waste sludge is limited by the ability of the hauling contractor to dispose of dewatered sludge which is influenced by road blockages, the 12 hour return trip schedule, availability of the contractor and poor weather conditions. Under ideal conditions, the decision to increase or decrease wasting is made based on a variety of factors that can change quickly. Winter conditions and associated temperature effects on process kinetics and impacts on operational functions further complicates the decision-making process. To address this, it is recommended that the SOP for adjusting the wasting rate based on effluent ammonia be conducted on a more frequent basis through the winter (i.e. 2-3 times per week rather that once a week as currently specified). The more frequent assessment can help capture changing conditions and allow for more time to respond. In addition, ph conditions in the bioreactor are historically low (ph 6.4 to 6.6) which tends to slow nitrification. During the winter the combination of low ph and low temperature could be contributing to lower nitrification efficiency. If elevated effluent ammonia events continue to be a feature of winter operation, addition of a source of alkalinity to the bioreactor should be considered Modelling of Treatment Process To assist in assessment of the treatment process, a Hydromantis GPS-X (version 6.4) model was developed, based on available wastewater fractionation data and process kinetic variables. GPS-X is a commercial wastewater treatment simulation software package that allows modelling of the biological nutrient removal process. The model was validated using available water quality characteristics for internal process streams, including primary effluent, fermenter VFA, and final effluent. To simplify model development and analyses, the GPS-X simulation was limited to the Stage 3 upgrades only (Figure 3-4). The Westside Regional WWTP process consists of three identical, parallel process trains, each with two bioreactors. Simulating only one of the trains reduces the level of complexity of the model while still providing sufficient detail for assessing process dynamics and treatment effectiveness.

18 Westside Regional WWTP Service Review 14 Figure Westside Regional WWTP GPS-X Process Schematic for Stage 3 In general, the model confirmed the AECOM process capacity rating for carbon, nitrogen and phosphorus removal under winter and summer temperature conditions. However, the model highlights some potential issues for operational consideration. In particular, the AECOM process capacity rating was calibrated using primary effluent and fermenter supernatant characterization data acquired during the summer period. Under these elevated temperature conditions, a high level of carbon fermentation in the mainstream wastewater and fermenter could be expected. Under winter conditions and wastewater temperature of 10 C to 12 C, the fermentation capacity would be reduced, due to reduced biological activity. Figure 3-5 provides an illustration of the decrease in VFA and primary effluent (PE) soluble COD for the year The reduced winter soluble carbon production may necessitate careful management to provide for both phosphate release in the anaerobic cells and denitrification in the anoxic cells. To provide for reliable winter nutrient removal, consideration should be made to increasing the availability of carbon to allow optimal feed to both the anaerobic and anoxic cells. This is discussed further in Section Figure 3-5 Seasonal VFA and PE Soluble COD trend 400 Splitter Box VFA 350 VFA Concentration (mg/l) /01/ /01/ /01/ /01/ /01/ /01/ /02/ /02/ /02/ /02/ /03/ /03/ /03/ /03/ /03/ /04/ /04/ /04/ /04/ /04/ /05/ /05/ /05/ /05/ /05/ /05/ /06/ /06/ /06/ /06/ /06/ /07/ /07/ /07/ /07/ /07/ /08/ /08/ /08/ /08/ /08/ /09/ /09/ /09/ /09/ /09/ /10/ /10/ /10/ /10/ /10/ /11/ /11/ /11/ /11/ /11/ /12/ /12/ /12/ /12/ /12/ Month

19 Westside Regional WWTP Service Review 15 Primary Effluent Soluble COD Soluble COD Concentration (mg/l) /01/ /01/ /01/ /01/ /01/ /01/ /02/ /02/ /02/ /02/ /03/ /03/ /03/ /03/ /03/ /04/ /04/ /04/ /04/ /04/ /05/ /05/ /05/ /05/ /05/ /05/ /06/ /06/ /06/ /06/ /06/ /07/ /07/ /07/ /07/ /07/ /08/ /08/ /08/ /08/ /08/ /09/ /09/ /09/ /09/ /09/ /10/ /10/ /10/ /10/ /10/ /11/ /11/ /11/ /11/ /11/ /12/ /12/ /12/ /12/ /12/ Month Additional Bioreactors There is space available on the existing site for an additional two bioreactor trains (of the same design as the existing), which would bring the total capacity to 44.8 MLD (2045). In other words, the existing biological nutrient removal process cannot meet the required treatment capacity of the 2065 design horizon within the boundaries of the existing site. An alternative biological nutrient removal process can be considered to increase capacity within the Stage 4 bioreactor footprint as described below Alternative Biological Nutrient Removal Process In order for the existing site to meet the wastewater flows of 2065, an alternative biological treatment process can be used. One option is to incorporate an integrated fixed film activated sludge (IFAS) into the existing continuous flow process. A second option is to convert the WWTP to a granular sludge process. A third option is to retrofit the bioreactors with a Bio-Mag system. All three processes would reduce the footprint required for biological treatment, and allow treatment of the additional wastewater flows to The three options are discussed in more detail below. The hydraulic modifications needed to accommodate the alternative processes would have to be reviewed at the predesign stage. Only the costs for Option 1 Upgrade to IFAS were estimated; the cost estimates for IFAS indicate that it is more cost effective to retrofit the Westside Regional WWTP with low-footprint technology for biological nutrient removal rather than build a second tertiary plant. The costs of all three options presented below should be further investigate in a subsequent Master Plan Option 1 Upgrade to IFAS The Stage 3 pre-design report makes reference to a technological adaptation which allows the nitrogen removal capability of the BNR process to be extended. Since nitrogen removal limits the treatment capacity of the current BNR process, any increase in nitrogen removal results in an overall increase in treatment capacity. Activated sludge processes, including BNR, rely on bacteria in suspension in the

20 Westside Regional WWTP Service Review 16 process liquid to carry out wastewater treatment. Control of the treatment process relies on careful management of the biological (activated) sludge inventory. The IFAS technology involves adding plastic media which are designed to promote growth of bacteria as a biofilm fixed to the media in addition to suspended growth bacteria. More specifically, by adding plastic carrier media within an aerated bioreactor cell, more ammonia oxidizing bacteria can be grown, allowing for a higher nitrogen removal capacity. The disadvantage of this approach is that an external source of carbon will be required to provide for denitrification, which is the final step of nitrogen removal (i.e., conversion of nitrate to nitrogen gas). The IFAS changes would also mean that the process could not be tuned for high phosphorus removal. The IFAS upgrade would necessitate more reliance on addition of alum for meeting the stringent effluent phosphorus objectives. To provide for assessment of the IFAS option, a proposal was provided by Veolia, a vendor of a patented IFAS process (Appendix A). The proposed improvements and associated costs and capacity were based on upgrading a single treatment train. Therefore, given the projected 4 available treatment trains at build-out, the IFAS upgrade could increase the Westside Regional WWTP average day flow capacity from 22,400 to 36,400 m 3 /d. Cost estimate (2015) dollars: $1.5 million per train including equipment and installation x 4 trains (two bioreactors per train) = $6 M Option 2: Upgrade to a Granular Sludge Process The granular sludge option is a significant evolution in treatment process, and it also has potential for extending the service life of the existing site. Granular sludge processes are designed to promote growth of dense granules that incorporate features of both suspended bacteria and fixed film carriers. By controlling diffusion of air and substrate through the granule, carbon, nitrogen and phosphorus removal process can take place. In effect, biological nutrient removal can be conducted in a single tank. Another key feature of the granule is that it has a very high settling velocity compared to conventional activated sludge biological solids. Consequently, granular sludge treatment processes need very little secondary clarification capacity and can be conducted in a single tank as a batch process. Given their high footprint, eliminating the need for secondary clarifiers at the Westside WWTP treatment plant site

21 Westside Regional WWTP Service Review 17 could on its own increase the site capacity by 40% to 50%. Additional process efficiencies associated with the ability to carry higher concentrations of bacteria further increase the site capacity. The first full-scale granular sludge processes that incorporate nutrient removal have only recently been commissioned in Europe, and there are no facilities in North America. Published data from the European facilities indicate that they could meet the current Westside Regional WWTP effluent objective of 6.0 mg N/L, but have not achieved the required total phosphorus removal efficiencies. A granular sludge process (NAREDA) in Holland is able to achieve an effluent total phosphorus of 0.3 mg P/L, which is slightly higher than the Westside Regional WWTP effluent limit of 0.20 mg P/L. However, it is expected that installation and continued improvement to mainstream granular sludge process will accelerate in the next 20 to 30 years, making it a viable technology for extending the existing site service life. Option 2 - Granular Sludge Cost Estimate (2015 dollars): This is a new and potentially revolutionary technology and as such a cost estimate is not currently available. This may become an economically viable option and should be considered in a subsequent feasibility study, once the process has become fully established Option 3: Upgrade to a BioMag System The BioMag System is an established small footprint process which can increase the biological treatment capacity and improve settling rates of existing activate sludge treatment processes. The BioMag System is an attractive option for the Westside Regional WWTP for the following reasons: a. The existing bioreactors can be retrofitted with a BioMag System. b. Apparent high rates of simultaneous nitrification and denitrification within the BioMag System which could reduce the effluent nitrogen to well below the required limits. c. With some ferric or Alum addition it would appear that the BioMag System can produce very low effluent suspended solids and quite low effluent phosphorus without filtration. However, filtration would be recommended but there may not need to be an increase in the filter media requirement. Disadvantages of the BioMag System are that the standard aeration system would likely need reconsideration due to the density of the mixed liquor which requires higher mixing energy the opposite from what we would see with conventional units. Hydraulics may also be impacted since low flows may lead to settlement in pipes. These potential limitations would need to be addressed in the pre-design stages. Option 3 BioMag System Cost Estimate (2015 dollars): The cost to implement and operate a BioMag System should be investigated in a subsequent study. 3.6 Secondary Clarifiers There are currently six secondary clarifiers which provides a peak hydraulic capacity of 33.6 MLD. The available space on the existing site only allows for two additional secondary clarifiers, resulting in a total peak hydraulic capacity of 44.8 MLD (based on existing unit processes).

22 Westside Regional WWTP Service Review Additional Secondary Clarifiers To achieve the design capacity of 73.1 MLD in 2065, a total of 12 secondary clarifiers would be needed. To accommodate the additional clarifiers, the existing site would need to expand into the adjacent nursery and an additional four secondary clarifiers would be needed to treat the projected 2065 wastewater flows (12 secondary clarifiers in total). Note that Option 1 (implementation of IFAS) discussed above for the alternative bioreactor process would not reduce the required number of secondary clarifiers. Option 2 for the alternative bioreactor process (conversion of bioreactors to Granular Sludge) would require very little secondary clarification capacity. Option 3 Upgrade to a BioMag System would also reduce the capacity required for secondary clarification. Both of these options have the advantage of reducing the number of secondary clarifiers needed, and effectively increasing the overall site capacity and would allow the design horizon (year 2065) wastewater flows to be accommodated within the existing site Alternative Secondary Solids Separation Processes Alternative small-footprint solids separation processes can be used instead of or to supplement gravity settling in conventional secondary clarifiers. Information provided by Veolia indicates that use of Dissolved Air Flotation (DAF) would substantially reduce the area required for biological solids separation compared to conventional secondary clarifiers (use of the Actiflo process would further reduce the footprint). Pressurized, supersaturated effluent is introduced into a tank alongside waste sludge. The supersaturate air forms small bubbles which rise in the tank, carrying suspended solids to the surface. A surface skimmer collects the floating sludge and discharges it to a hopper for pumping to the next process step (e.g. back to bioreactor). In this scenario, for the Stage 4 expansion, no new secondary clarifiers would be built (i.e. total of 6 secondary clarifiers instead of 8). The DAF units would be constructed in a building occupying the space originally allocated to secondary clarifiers #7 and #8. The DAF process could later be expanded as needed to accommodate 2065 wastewater flows within this available space, and expansion of the WWTP site would not be required. Sizing and costing of these processes would require a detailed flow and solids loading analysis. However, it can be said that capital costs would be lower and operating costs would be higher compared to conventional secondary clarifiers. Therefore, conventional secondary clarifiers should still be used to the extent possible within the available space, supplemented by a small footprint process such as DAF or Actiflo to handle peak hydraulic and solids loads. Cost Estimate (2015 dollars): 2 DAF units cost < secondary clarifiers #7 and #8. The operating costs would be higher for this alternative due to the higher energy demand associated with DAF, and the need for polymer use (advancing technology may greatly reduce or eliminate the need for chemical addition in the near future). Therefore, use of the DAF (or other alternative technology) rather than gravity settling for separation of biological solids should be designed to handle peak flows and loads as far as possible, and the use of gravity settling should be maximized to the

23 Westside Regional WWTP Service Review 19 extent possible. This combination (gravity settling with DAF or other for peak flows and loads) would have to be investigated in more detail to establish realistic capital and operating cost comparisons. Cost Estimate (2015 dollars): capital cost will be lower for DAF/SC combination compared to twelve SC s for 2065 capacity. 3.7 Tertiary Filters There are currently four effluent disc filters operating (three duty and one standby). The peak flow capacity of each disc filter is 22 MLD, creating a total peak capacity of 88 MLD. Therefore, the existing hydraulic capacity should be sufficient to accommodate the design flows of 73.1 MLD in Cost estimate (2015 dollars): Nil no improvements required. 3.8 UV Disinfection The existing UV disinfection process is designed for peak flows of 33.6 MLD using six banks of bulbs. Due to the small footprint required, it is assumed that there is available space to accommodate additional UV disinfection. The capacity of the existing UV disinfection process will need to double to accommodate the peak wastewater flows of Cost estimate (2015 dollars): $1 million to twin existing process, including channels and flow split. 3.9 Outfall and Effluent Pump Station Effluent from the plant is pumped to Okanagan Lake via an effluent pump station and an existing outfall pipe and submerged diffuser. The effluent pump station uses screw pumps and has a reported capacity of 440 L/sec, or 38 MLD. However, the outfall capacity is limited to 165 L/sec (or 14.3 MLD). Both of these components must be upgraded to meet the 2045 design flows of 518 L/sec. RDCO is presently investigating improvements to the outfall, or the effluent pump station, or both in parallel to the preparation of this report to increase their capacity to 445 L/sec. An allowance only is carried in this report as the actual approach and costs are being developed by others. Cost Allowance (2015 dollars): $2 million Waste Solids Thickening and Dewatering The waste activated sludge from the bioreactors is thickened to 3% to 7% using dissolved air flotation (DAF). Waste sludge from the bioreactors and fermenters is currently dewatered and trucked off-site for disposal. Dewatering of waste solids is undertaken using the centrifuge process. Analysis of the capacity of the existing centrifuge process and the need for future expansion is not specifically addressed in the 2010 AECOM Pre-design Report, and is beyond the scope of this study. Installation of a third centrifuge

24 Westside Regional WWTP Service Review 20 and/or expansion of the waste biological sludge thickening process may be required to serve the 2065 wastewater flows, particularly if redundant process units are desired. It is assumed that there will be sufficient space on the existing site for these expansions if needed, since these processes have a relatively small space requirement. Cost Estimate (2015 dollars): N/A Primary Sludge Fermenters Fermenter Capacity The Westside Regional WWTP currently utilizes two existing primary sludge (PS) fermenters to generate volatile fatty acids (VFAs) for phosphorus removal. The fermenter acts as a gravity settler allowing PS to settle and thicken. Soluble carbon in the form of VFAs in the fermenter supernatant is transferred to the bioreactor primarily to initiate phosphorus release. VFAs released into the centrate during centrifuge dewatering is also an important source of soluble carbon which enters the bioreactor as part of the PE stream and can be used to optimize denitrification. The objective is to provide sufficient time for hydrolysis and fermentation of the coarse solids to VFAs without allowing methanogenic activity to be established. Since methanogenic activity is also depressed during winter conditions, SRT could be increased to increase VFA production. Monitoring of the headspace methane concentration could be used to precisely control SRT. Fermenters are typically designed to provide for 6 days retention time of the thickened sludge. Carbonaceous material is hydrolyzed and subsequently fermented to primarily acetic acid and propionic acid, the main source of VFAs to the treatment process. In the presence of VFAs and anaerobic conditions, polyphosphate accumulating organisms (PAOs) release stored phosphate and take up the VFAs as an energy source. When transferred to an aerobic environment the PAOs uptake phosphate in a greater amount than was released. Phosphorus removal is achieved by harvesting the PAOs as wasted sludge. Therefore, reliable production of VFAs is an important process objective. For the purposes of this report, the capacity of the existing fermenters was assessed to determine upgrade requirements. Based on these estimates (Table 3-2), a third fermenter will be required to meet the year 2065 projected flows assuming current VFA requirements, or other measures can be taken to increase carbon availability as discussed below. If alum is used to enhance primary treatment to increase capacity then phosphate would also be removed resulting in lower VFA requirements for the process.

25 Westside Regional WWTP Service Review 21 Table 3-2: Fermenter Capacity Assessment Fermenter Design Parameter Stage 3 (existing) Stage 4 Stage 5 (Year 2065) Number of Units Sludge Storage per unit, m Total Sludge Storage, m Thickened Primary Sludge Production (summer ADF), m Sludge Retention Time, days Note: 1. Sludge production estimated based on Stage 3 mass balance The first approach to increase the availability of carbon should be to increase the fermenter capacity. As shown in Table 3-2, Stage 5 would require 3 fermenters in total. This cost would be incurred regardless of whether or not alternative small footprint processes such as IFAS and DAF are implemented to avoid site expansion to 2065 (it appears that sufficient space is available on the existing site for a third fermenter). A second option for increasing fermenter VFA production may be to increase sludge loading by diverting a small stream of TWAS or fats, oils or grease (FOGs). Fermentation of TWAS will increase VFA content but will also increase orthophosphate concentration in the supernatant. This approach is appropriate only under close control and conditions when there is excess P removal capacity in the mainstream process. A third option is to provide for increased insulation and heating for the fermenter. This in effect is a retro-fit option which may not be easily implemented or cost-effective. A final possible option for increasing carbon availability is to install bulk storage and dosing facilities to allow use of a commercial source (i.e., methanol). It is expected that addition of a bulk carbon source will be necessary to increase the nitrogen removal capacity beyond the rated capacity. Due to the increased operating costs and higher associated carbon footprint, use of an external carbon source should be considered an option of last resort. Cost Estimate (2015 dollars): Fermenter #3 approximately $500, Process Reliability Reliability of the WWTP process components was assessed based on BC Ministry of Environment standards. Table 3-3 provides a summary of the expected reliability standards, as documented in the BC Wastewater Regulation, for critical treatment components at the Westside WWTP. Based on these standards, the components meet the reliability requirements.

26 Westside Regional WWTP Service Review 22 Table 3-3: BC Wastewater Regulation Reliability Requirements for Wastewater Facilities Critical Treatment Components for Westside Regional WWTP BC Ministry of Environment Reliability Category I Requirements Treatment System Available Capacity When Largest Unit Out of Service (%) Backup Power Source Meets Reliability Standard Notes Blowers multiple units n/a yes Yes two 150Hp blowers with one 200 Hp standby Aeration basins multiple units 75 yes Yes 6 bioreactors installed Disinfection basins multiple units 75 yes Yes 3 channel with 2 UV banks per channel Primary multiple units 50 yes Yes 3 clarifiers installed sedimentation Final sedimentation multiple units 75 yes Yes 6 final clarifiers installed Degritting n/a - optional Yes 1 vortex style unit installed Effluent filters 2 minimum 75 yes Yes 3 units installed, each rated for 65% peak flow 3.13 Effluent and Residual Quality The alternative options discussed elsewhere in this report are designed to maintain effluent quality at the current requirements of the plant Operational Certificate. Maintaining the quality of solid residuals resulting from wastewater treatment to meet requirements for beneficial use depends in part on an effective source control program, to limit and/or prevent the discharge of problem contaminants to sewer (e.g., metals, problem organic compounds, etc.). The alternative and use of DAF for solids separation process options discussed in this report (e.g., conversion of biological process to IFAS, expansion to meet future capacity at the existing site or at an alternative site), should have little impact on the quantity and quality of the residual solids produced. Use of CEPT may potentially capture more metals from the liquid stream, incorporating them into the solids. Digestion of residual solids can be used to significantly reduce the quantity of residual solids produced (by up to 50%). However, the existing WWTP site cannot accommodate conventional anaerobic digestion, due to limited space, substantial expansion of the existing site or construction of a separate solids processing facility at an alternate site would be needed if conventional anaerobic digestion were to be implemented. Recovery of resources (e.g., biogas) could also be considered. However, transport of waste solids to an alternative site and management of high-strength sidestreams would be problematic if the site was far from the existing WWTP (high-strength sidestreams could be discharged to the sewer collection system but generally separate pre-treatment of sidestreams is preferred before discharge to the main liquid stream). Alternative small-footprint processes could be considered. The need for solids treatment and the type of treatment used will depend to some extent on the planned end use of the product.

27 Westside Regional WWTP Service Review 23 Trace Organic Compounds (TOrC) include common household chemicals, pharmaceuticals, personal care products, pesticides, herbicides, and innumerable industrial chemicals. In today s society tens of thousands of chemicals are used. These chemicals can be transported to wastewater treatment plants and if not removed or converted to other substances, they may be discharged to surface water or ground water. Some of the chemicals are complex and not easily broken down in the treatment process, and can persist in surface and ground water for long periods of time. There are also concerns regarding the potential impacts of these chemicals on drinking water and biosolids application to land (WERF, 2008) 1. Mechanisms which have been shown to degrade or remove TOrC include volatilization, adsorption (transfer from aqueous phase to solid phase), biological degradation, chemical oxidation, membrane filtration, and ultraviolet radiation. Research has shown that the efficiency of TOrC removal is linked with solids retention time (SRT) in biological treatment processes. It has also been shown that treatment plants using both nitrification and denitrification and/or high sludge ages (approximately 15 days) exhibit better removal for a variety of TOrC than for plants operating with lower SRTs. The diverse bacterial community that is present with nitrification and denitrification and the longer exposure time may be responsible for improved removal of TOrC, and this has implications for process selection for future upgrades to biological processes at wastewater treatment facilities (WERF, 2008) 1. The Westside Regional WWTP is designed and operated for full nitrification and denitrification (long SRT), and this is likely to continue into the foreseeable future. Source control initiatives aimed at TOrC could include public and private sector education, and the implementation of product bans or other control measures by Federal and/or Provincial authorities. The existing Operating Certificate limits for the Westside Regional WWTP are very stringent, and there seems little reason to believe that this will change in the foreseeable future. As noted earlier in this report, the plant total nitrogen limit has been exceeded during winter operation, and this should be the focus of process optimization (close process monitoring, SRT control to maximize nitrification, possible use of methanol for denitrification during cold temperature operation) Energy Efficiency The largest energy demand at biological activated sludge wastewater treatment plants is due to aeration of the activated sludge tanks. Maximizing efficiency of energy use should include detailed evaluation of existing aeration blower efficiency, available alternative technologies (e.g., turbo blowers), and enhanced control of aeration to avoid wasting energy. Our recent experience at the Norm Wood Environmental Centre in the City of Campbell River found that upgrading the aging constant-speed centrifugal aeration blowers with variable-speed turbo blowers resulted in a reduction in energy requirements of between 15 and 20 percent. Energy efficiency at the WWTP can also be improved by incorporating of solar power and LED lighting, heat recovery from the wastewater stream, and plant power audits to evaluate opportunities for energy savings. 1 Water Environment Research Foundation (WERF), Technical Brief: Trace Organic Compounds and Implications for Wastewater Treatment. WERF / IWA Publishing. Alexandria, VA

28 Westside Regional WWTP Service Review Cost As noted elsewhere in this report, the Stage 4 expansion at the existing WWTP site will provide treatment for an average day flow of 16,800 m 3. Conversion to other processes can be used to increase the capacity of the site to treat the projected 2065 wastewater flows, or a second tertiary WWTP could be constructed. A direct comparison of the cost to increase the capacity of the existing site and the cost to construct and operate a second tertiary WWTP is difficult due to, for example, the uncertainty in the cost of future low footprint technologies, treatment capacity requirements at the second set, changes to the configuration of the collection system, pumping requirements, and a new outfall. To assist in this comparison, an order of magnitude cost estimate was developed for a second tertiary wastewater treatment plant with an average day flow treatment capacity of 14,200 m 3 a flow equivalent to the increased capacity of Westside Regional WWTP through the conversion of existing unit processes discussed in the preceding sections. Approximate cost of a second tertiary WWTP: Cost of second tertiary treatment plant located in a major development node (e.g. Westbank First Nation IR10 or the District of Peachland) designed for an average day flow of 14,200 m 3 is estimated at $50 million to $60 million, not including modifications to the conveyance system, land purchase or community consultation (existing WWTP to Stage 4 only). Approximate cost to convert to other processes: Cost of converting processes at existing wastewater treatment plant to increase the treatment capacity by 14,200 m 3 to treat the projected 2065 wastewater flows is estimated at $23.25 million (see Table 3-4 below for cost summary and Sections 3.2 through 3.8 for more detail). Table 3-4: Expansion Costs Beyond Stage 4 (to Projected 2065 Wastewater Flows) Item Capital Cost Primary Treatment 3 rd influent screen $400,000 3 rd and 4 th vortex grit chambers $600,000 4 th, 5 th, 6 th, and 7 th Primary Clarifiers NO ADDITIONAL COST Implement CEPT $500,000 Secondary Treatment Conventional biological process to IFAS $6,000,000 2 additional secondary clarifiers, flow split and piping NO ADDITIONAL COST 2 DAF units to supplement secondary clarifiers $1,500,000 3 rd Fermenter $500,000 Tertiary Treatment Twin UV disinfection $1,000,000 Outfall and Effluent Pump Station Improvements to outfall and/or effluent pump station $2,000,000 General Site Requirements Expand Odour Control $1,000,000 General Electric and Civil Upgrades $2,000,000 Subtotal $15,500,000 Contingency Allowance, 50 percent $7,750,000 Total $23,250,000

29 Westside Regional WWTP Service Review 25 The long term operation and maintenance costs will be significantly greater for operation of two plants compared to one. Although the unit processes would be smaller at the two plants, the same sequence of processes would be required as at a single plant (e.g., headworks, primary treatment, biological treatment, solids handling, etc.). Therefore it is apparent that a single facility is more cost-effective, provided that the site space is sufficient to serve the build-out wastewater flows, and the option of expanding the existing site into the adjacent nursery should be revisited if feasible. However, identification of an alternate site can still be beneficial for the long-term future (e.g. for a dedicated solids processing facility with reserve recovery). As noted earlier in this report and as summarized in Section 4 below, expansion of the existing plant processes on the existing site will serve the projected 2045 wastewater flows. Opportunities for expanding site capacity that should be evaluated in a future feasibility study include the following: conversion of biological process to IFAS or other low-footprint BNR technology to treat the projected 2065 projected wastewater flows; replacement of at least some of the secondary clarifiers with an alternate solids separation technology such as DAF to treat the projected 2065 projected wastewater flows; use of CEPT during periods of high flow and loads to allow 7 primary clarifiers to treat the projected 2065 projected wastewater flows; use of 7 primary clarifiers without chemical addition to treat the projected 2065 projected wastewater flows, with the resulting increased loading in the primary clarifier overflow being accommodated by the biological and secondary solids separation processes; use of solids digestion/resource recovery at an alternative site; and expansion of the existing site boundary to allow servicing of the projected 2065 wastewater flows using the existing processes. 4 Site Life Expectancy Assessment This section presents a high level, desk-top based analysis of future WWTP sites which can be considered as the current facility approaches its site space limitation. In this section, ultimate site life expectancy is taken to mean the future time when the existing property is no longer the most affordable location for expansion to meet new capacity. 4.1 Current Site As described in Section 3, the capacity of the existing site (using the existing unit processes) is limited to the projected 2045 wastewater flows. The governing processes are the bioreactors and the secondary clarifiers (outfall and effluent pump station notwithstanding). It appears that all of the other processes can be expanded on the existing site to handle the projected 2065 wastewater flows. If the bioreactors are successfully converted to a different process using available technology such as IFAS, the site can meet the 2065 capacity within the existing site constraints. This will require increased chemical use to meet the effluent discharge criteria (i.e. methanol for denitrification and alum or similar for removal of residual phosphorus). Alternatively, it is likely that the ongoing

30 Westside Regional WWTP Service Review 26 development of other alternatives such the granular sludge process will allow expansion within the existing bioreactor footprint with low or possibly no chemical use. The secondary clarifiers will be the remaining bottleneck that limits the current site to the projected 2045 wastewater flows. Two alternatives for expanding this process step beyond 2045 would be expansion of the site into the adjoining nursery to allow future addition of four more secondary clarifiers (twelve in total), or replacement of some of the secondary clarifiers with an alternative solids separation process such as DAF within the boundaries of the current site. Expansion of the existing site could also allow implementation of solids digestion with resource recovery. 4.2 Potential Future Sites A review of potential new sites was made for future planning when the current site reaches capacity or a critical social (e.g. odour) or environmental (e.g. disposal of effluent) threshold prevents future use or expansion. It is both timely and prudent to consider new sites now so that land use planning and acquisition can be considered well in advance of the time when needed. In framing this review, Table 4-1 summaries the three general options considered in this report for increasing land space. Table 4-1: Potential New Options No. Name Description Remarks 1 Retain existing plant site Additional space through land acquisition of adjacent nursery property. 2 New Site Locate and develop an entirely new site with sufficient future space. 3 Distributed Sites Build satellite plants in areas of new growth, or relocate and extend the biosolids portion of the existing plant to create space. Land can be leased back to nursery until it is needed in the future. Possible agreement could include seasonal supply of reclaimed water for irrigation. Existing collection system and existing service area are primary factors in viability of this option. Effluent disposal and a regional biosolids management plan are primary factors in these options. This section presents the approach, analysis, and discussion of the options considered Site Selection Methodology for New Sites Potential areas for a new WWTP site within the west side of the RDCO were screened against the constraints listed in Table 4-2. Screening was first performed using ArcGIS (version 10.3) and shapefiles available via the RDCO mapping website. Data not available on RDCO s website were obtained from individual jurisdictions. Once the GIS results were obtained, a site by site review was made to confirm the actual practicality of using the site from both constructability and political basis.

31 Westside Regional WWTP Service Review 27 Table 4-2: GIS Search Constraints Constraint Description Remarks Solids Within 2 km of Highway 97 Trucking of biosolids within urban area. Outfall Within 3 km of Okanagan Lake s shoreline Practical limit of effluent conveyance to a lake outfall. Odour More than 100 metre (or 200 metres) Minimize proximity to odour receptors and Collection from existing residential areas Within one kilometre of 450 mm and larger or 600 mm and larger diameter trunk sewer pipe (); and, possibility of negative odour complaints. For new trunk sewer routing efficiency, to ensure accessible transfer of liquids from major sewer lines. Space An area greater than 0.04 km 2 Minimum footprint of a WWTP with more space than existing site. Topography Slopes of the land less than 4 percent. The process structures of a WWTP are set to elevations which provide gravity flow within the plant and minimize pumping. Elevation a Less than 35 metres higher than collection system. Notes: a) Constraint applied manually and not using GIS Results for Potential New Sites Practical limit of sewage pump vertical lift. Given the significant cost in replacing the collection trunk sewers, close attention was paid to minimizing the level of changes in replacing or redirecting the trunk sewers. In addition, if the site were to be used for solids processing only, proximity to a trunk sewer would be desirable so that highstrength side streams such as centrate could be easily routed bac to the liquid treatment facilities (preferably after pre-treatment). Therefore, the largest diameter trunk pipe size was used to limit locations considered. However, the GIS analysis showed a high sensitivity to the selection of limiting trunk sewer size in the search criteria. Initially, the search criteria used 600 mm. Since the resulting areas were so limited, the criteria was expanded to 450 mm. Table 4-3 shows the number of metres of each trunk sewer size (300 mm and larger) in the collection system (including Peachland), and the probable cost to replace that level of collection system. Table 4-3: RDCO West Side Trunk Sewer Size (mm) Number Total Linear Metres Cost to Replace Total Cost to of Pipes in System ($/m) Replace $ 300 to , $8,995, to , $4,840, , $4,320, , $1,380, to , $2,380, , $1,280, $315,000 As shown in Table 4-4, the total replacement value of the trunk collection system is over $24 million (before contingency) excluding manholes and lift stations. If manholes, lift stations and contingency were applied, the total cost or replace the trunk collection system would be over $50 million. Therefore, minimizing the level of replacement is a major factor. In considering this fact, the GIS analysis assumed trunk sewers 600 mm and smaller would remain and that a new WWTP would need

32 Westside Regional WWTP Service Review 28 to be within one (1) kilometer of a 600 mm trunk. A second, wider search used the cut-off size of 450 mm trunk sewer. The following two sections discuss these results mm Trunk Sewer Limitation Figure 4-1 in Appendix A shows the resulting land areas within 1 kilometer of a 600 mm trunk sewer (for both 100 metre and 200 metre residential area setbacks). While the GIS search found no new potential areas greater than 0.4 km 2 in area where a 200 metre setback could be provided, it did result in potential new (or supplementary) sites within West Kelowna, all zoned as agricultural A1 providing a 100 metre setback including: Existing site and adjacent Bylands nursery property. South of Westbank Business District - Brown Road (near Harmax Farm Road). North of Boucherie Road. East of Welton Road. Undeveloped land south of IR 9. South of Boucherie Road. Immediately east of IR 9. These results capture sites that could be used as an entirely new site or as a possible sister site for headworks, primary treatment (including fermenters), and equalization whereby space allocated for those unit process at the existing site can be converted to additional secondary treatment. However, this is neither typical nor recommended. The other GIS qualifying site within the Westbank business area and IR 9 was eliminated as this option is not justifiable for public impact reasons mm Trunk Sewer Limitation Figure 4-2 in Appendix A shows the resulting land areas within 1 kilometer of a 450 mm trunk sewer (for both 100 metre and 200 metre residential area setbacks). However, only some of these locations are viable upon inspection of existing land use and terrain. Areas were eliminated if they were located on steep slope or were higher than elevation 400 metres (based on the practical limit of pumping head from the existing collection system). Potential new sites include: Peachland Existing site of the Peachland Elementary School. This option assumes the elementary school can be relocated and includes the capital cost of public engagement involved with building a new elementary school. Public impact is severe. West Kelowna sites identified in previous section. While the Peachland site is technically possible, this location is academic only. The forcemain used to convey Peachland sewage to the Westside Regional WWTP does not have capacity to convey the future flows and would have to be replaced or twinned. A large raw water pump station to convey the flows in the reverse direction further complicates. While this option is flawed as a new WWTP for the entire region, it is discussed further as a possible satellite plant. 4.3 Distributed or Satellite Plants Satellite plants provide an opportunity of redirecting inflow away from the Westside Regional WWTP and thereby extending the expect life of the plant. Areas identified for future growth offer the

33 Westside Regional WWTP Service Review 29 opportunity to locate a new satellite WWTP achieve this with minimal changes to the collection infrastructure and offers advantages in the collection system for the growth area. Under this scenario, satellite plants are assumed to be tertiary plants designed for near zero odour release and discharge of solids to the Westside Regional WWTP. Essentially, the plants would recover 80 to 90 percent of the influent as reclaimed water. The reclaimed water would be disposed either by a new outfall to Okanagan Lake or through reuse of reclaimed water (e.g. drip irrigation at nurseries or vineyards, or spray irrigation of golf courses and park space). Three possible configuration were considered two for liquid treatment and one for solids treatment Peachland Future Growth Peachland growth is expected to exceed the average annual growth driven primarily by two large proposed developments, each for over 2,000 units. Growth up to 15,000 persons would more than double the current population served. If this growth, or this growth plus the current Peachland population served, were accommodated at a new WWTP in Peachland, a reduction in flows of about 20 percent could be realized at Westside Regional WWTP IR 10 Future Growth Based on the Casa Loma Lift Station Report, Westbank FN IR 10 is projected for an additional 20,000 persons. Like the Peachland option, a new satellite plant would provide a reduction in flows of about 20 percent could be realized at Westside Regional WWTP Solids Sites A final option, though more complicated, is to relocate all the solids processing from the existing site to another site within pumping distance (dewatering and truck loading). This option would allow land currently used for solids processing to be converted to liquid unit processes. Besides the land identified with West Kelowna in the previous sections. 5 Cost of Service Review This section presents a high-level cost of service review to identify opportunities to reduce costs and improve service. Areas of focus include operations, asset management, and overhead. Overhead costs are discussed separately from operations and maintenance costs under the heading Section 5.3 Overhead. 5.1 Operations Opportunities for service improvements and cost savings through changes to process and operations were identified in Section 3 and Section 4 and are summarized here: 1. The overall treatment capacity of the existing site could be increased by acquiring land from the adjacent nursery. 2. The capacity of the primary clarifiers could be increased through CEPT during periods of peak flow.

34 Westside Regional WWTP Service Review The standard operating procedure (SOP) for adjusting the wasting rate based on effluent ammonia could be amended to be conducted on a more frequent basis through the winter (i.e. 2-3 times per week rather that once a week as currently specified). The more frequent assessment can help capture changing conditions and allow for more time to respond. 4. The plant effluent total nitrogen limit has been exceeded during winter operation, and this should be the focus of process optimization (close process monitoring, SRT control to maximize nitrification, possible use of methanol for denitrification during cold temperature operation). 5. Upgrading the bioreactors to a Granular Sludge Process or a BioMag System reduces, and potentially eliminates, the need for additional secondary clarifiers. Reducing the number of secondary clarifiers effectively increases the overall treatment capacity of the existing site. 6. The existing secondary clarifiers should still be used to the extent possible within the available space to minimize operating costs, supplemented by a small footprint process such as DAF or Actiflo to handle peak hydraulic and solids loads. 7. Energy efficiency at the WWTP can also be improved by upgrading the existing blowers to turbo blowers, incorporation of solar power and LED lighting, heat recovery from the wastewater stream, and plant power audits to evaluate opportunities for energy savings. In order to assess the existing operation and maintenance (O&M) costs for the Westside Regional WWTP, two other similar BNR type plants were compared; Penticton and Whistler. The plants are similar in liquid and biosolids treatment, are relatively new, and are similar in size. It is important to emphasize that each WWTP is unique and comparing cost directly can be misleading. For example, the RDCO funds UV lamp replacements through the O&M budget while the City of Penticton funds the replacement though a separate capital budget. A direct comparison can be further blurred when comparing the accounting practices of a regional district to that of a municipality. That being said, a high-level comparison of operating costs between WWTPs provides some indication as to whether or not the costs are at a reasonable level. In comparing the costs, we have allocated accounting costs to a more level platform. We further broke the cost information down into three broad categories: labour, energy and general O&M. These were then generated on a per cubic meter of liquid treated. Energy is the total of electricity and natural gas, labour is self-explanatory, and general O&M is the sum of the remainder. Figure 5-1 illustrates the overall cost breakdown in the three categories at each plant, on a per cubic meter basis. Note that overhead costs are included within each of the three categories and are discussed in more detail in Section 5.3.

35 Westside Regional WWTP Service Review 31 Figure 5-1 O&M Cost Summary for Westside Regional, Penticton, and Whistler WWTPs As shown in Figure 5-1, all three plants had very similar operating and maintenance costs in Penticton had slightly lower general O&M costs, but some of the accounting costs codes for Penticton may include labour. Each plant is staffed during the day, 7 days a week, but with reduced staffing levels on weekends. On average, general O&M costs represent about 53%, energy 12% and labour 35%. Not included in this cost data are costs associated with asset depreciation and replacement funding. Also, biosolids costs were limited to onsite solids processing O&M costs alone, since each plant has quite different biosolids treatment systems and disposal costs, which are accounted for under different cost centers. Each of the WWTPs dewater and truck biosolids to a receiving location, and these costs are included. Long term costs can be expected to increase as flows and biosolids generated at the plant increase. Depending on long term technologies employed at the plant, for example anaerobic digestion, some energy recovery options and cost recovery may be possible, but this would be partially offset by increased labour and general O&M costs. It is very important that a long term biosolids management plan be developed for the plant, as the cost uncertainty in this aspect of future O&M (and capital) costs is high. Typically, plant O&M costs for solids treatment (e.g., dewatering, composting, incineration digestion, land application, etc.) are 50% of a plant s total O&M costs. Capital costs and locating such treatment facilities and ultimate disposal sites can be challenging and costly. In this regard, a regional solution may provide a better life cycle cost than one strictly dedicated for the Westside Regional WWTP.