staff report #pw2021-09

PW2021-09 Water Supply Capacity of 17

STAFF REPORT #PW2021-09

Council 4/26/2021

Amendments: [no]

Submitted to: Council

Submitted by: Peggy Slama, Director of Public Works, Engineering & Environmental Services

Subject: Available Drinking Water Supply and Wastewater Treatment Plant Capacity

PURPOSE The purpose of this report is to provide an update to Council on the status of the available drinking water supply and wastewater treatment capacity remaining to service development including options to mitigate limitations while the upgraded and expanded water treatment plant is constructed.

RECOMMENDATION THAT Report PW2021-09 Available Drinking Water Supply and Wastewater Treatment Plant Capacity be received; AND THAT Council direct staff to obtain legal advice on the risks associated with proceeding to issue the Request for Proposal for engineering services for the design and contract administration of the drinking water treatment plant expansion prior to a completed water supply agreement with the Town of New Tecumseth as the next step in securing safe and reliable expanded water treatment capacity; AND THAT the Request for Proposal for engineering services for the water treatment plant expansion incorporate advancement of the design and construction of the chlorine contact infrastructure (Opportunity 4B); AND THAT staff initiate discussions with the Town of New Tecumseth and the Town of the Blue Mountains to reduce the amount of water supplied these municipalities until the water treatment plant expansion is complete.

AMENDMENTS None


1. BACKGROUND

The Raymond A. Barker Water Treatment Plant (WTP) was constructed in 1998 to meet an immediate need for enhanced surface water treatment and to support planned development within the Town of Collingwood’s municipal boundaries. The rated WTP capacity on the Town’s Municipal Drinking Water License (MDWL) is 31,140 m3/day. However, the WTP has performance restrictions due to age and deterioration of existing membranes as well as limited chlorine contact infrastructure that was not designed to satisfy more stringent disinfection requirements that were imposed by the Ministry of the Environment, Conservation and Parks (MECP), formerly the Ministry of the Environment (MOE), in the early 2000’s. While staff continue to do targeted replacement of the ageing membrane filters to maintain filtration capacity at the WTP, a 2016 Staff Report to Council (Report PW2016-23-C) regarding the regional pipeline and an additional water supply request from the Town of New Tecumseth noted concerns related to elevated chlorine dosing that would be required to satisfy anticipated future water supply requirements until the expansion of the WTP could be completed. A review of the disinfection calculations in 2018 determined that the Town was approaching the upper limit of the existing WTP’s disinfection capabilities during winter while remaining within drinking water quality aesthetic targets for chlorine. Staff subsequently engaged the services of GHD Group to evaluate alternative design concepts and identify an interim solution to address the chlorine contact constraints until the expansion of the WTP could be completed. A long list of alternative solutions was discussed with staff and operators and feasible alternatives that could be integrated into the expansion of the WTP were evaluated further including UV disinfection, chlorination of the raw water at the intake pipe and construction of a new chlorine contact tank. GHD provided a final report to staff in July 2019 that identified two potential interim disinfection improvements: install UV disinfection, or install an additional chlorine contact tank. The capital cost and constructability issues associated with both these alternatives were deemed too significant to warrant proceeding at that time given the expectation that the expansion would be proceeding to design in late 2020 or early 2021. In the meantime, GHD recommended that the Town continue to operate the WTP using the existing treatment process and increase the chlorine dose as required to provide sufficient disinfection. GHD also recommended that the expansion process for the WTP be accelerated. A recent significant increase in development applications and growth in Collingwood has renewed concerns about the ability of the existing WTP to service the desired level of growth while the planned WTP expansion is underway. This development pressure, along with the operational limitations of the existing disinfection process at the WTP, requires a detailed analysis on available water supply capacity and regular review of the allocation of water supply for development. While development pressures today implement stress on the available WTP capacity, the same analysis should be completed on the wastewater treatment capacity available at the Wastewater Treatment Plant (WWTP). Regular review of the allocation of wastewater treatment capacity will help the municipality determine the timing of a WWTP expansion to ensure adequate capacity for future development. This expansion process will follow much the same multiyear timeline as the water treatment plant expansion, and appropriate planning will be required.


2. INPUT FROM OTHER SOURCES

• Technical assessment and opinion from GHD consultants (July 19, 2019).

• Review of previously provided chlorine disinfection guidance and recommendations by Ainley Group (August 2, 2016).

• Monitoring data from the existing water treatment plant operations.

• Status of development applications. This report has been the subject of internal discussion among senior management and with the Town solicitor.

3. APPLICABLE POLICY OR LEGISLATION

• Town of Collingwood Community Based Strategic Plan (2020)

• Safe Drinking Water Act, including Town-specific permits and approvals issued in accordance with this Act

• Environmental Protection Act

• Planning Act

4. ANALYSIS

When looking at the Town’s ability to service new development, both drinking water and wastewater treatment capacity must be considered. Wastewater Treatment Plant Capacity The Environmental Compliance Approval issued for the Collingwood WWTP requires that a wastewater treatment plant expansion be initiated when the annual average day flows over the most recent three (3) years reaches eighty percent (80%) of the rated wastewater treatment capacity. The annual average day flow at the wastewater treatment plant from 2018 through 2020 accounts for approximately seventy-two percent (72%) of the rated treatment capacity. When a five percent (5%) factor of safety is applied to the rated treatment capacity and existing approved development allocations are considered, 5,112 m3/day, or 5,036 Single Dwelling Units (SDUs) of wastewater treatment capacity remain available for new development applications. The available wastewater treatment capacity is declining as development in the Town increases, and wastewater capacity allocation should be considered when future development applications are being reviewed to ensure it is does not reach a critical level. Drinking Water Treatment Plant Capacity The rated capacity of the Collingwood WTP is 31,140 m3/day. This rated treatment capacity can be achieved in the warmer months; however, this capacity is currently only achievable in the winter if the chlorine residual leaving the WTP is approximately 2.75 mg/L due to limited chlorine contact tankage at the WTP. The chlorine contact infrastructure at the WTP is undersized for the enhanced disinfection requirements that were mandated by the MECP following the Walkerton tragedy. Chlorine disinfection is less effective in cold water, and as a result, the chlorine dose required to achieve the required level of disinfection needs to increase as the untreated water temperature decreases (i.e. during winter).


From a regulatory perspective, the upper limit for chlorine concentrations in a drinking water distribution system is 4.0 mg/L and the optimum target concentration is 0.2 mg/L (Procedure for Disinfection of Drinking Water in Ontario, 2019). The Safe Drinking Water Act also requires that a minimum free chlorine residual concentration of 0.05 mg/L be maintained in the distribution system at all times. Operations staff are currently using a chlorine dose of 1.9 mg/L (resulting an average chlorine residual of 1.85 mg/L leaving the WTP) during cold water conditions to ensure sufficient disinfection for existing winter water supply demands, which results in a winter water treatment capacity ranging from 19,872 mg/L to 20,995 mg/L with typical winter water temperatures. Water Supply Demands The Town of Collingwood (Collingwood) supplies water to customers within its municipal boundaries, as well as to the Town of New Tecumseth (New Tecumseth) and the Town of the Blue Mountains (Blue Mountains) in accordance with water supply agreements. Over the past five years, the combined water demand from all three municipalities has fluctuated, with a five year average of 24,049 m3/d (Table 1, Figure 1). Table 1 – Maximum Day Demands (MDD) for the Collingwood Drinking Water System

2016 2017 2018 2019 2020

MDD (m3/day) 24,670 21,143 24,277 25,576 24,577

% of Rated Treatment Capacity 79% 68% 78% 82% 79%

The MDD for a water system is the standard design criteria used when sizing a water treatment plant, therefore it is also used to determine the appropriate timing for a water treatment plant expansion. When the MDD exceeded the 80% treatment plant capacity in 2019, a Municipal Class EA for the water treatment plant expansion and upgrade project was initiated. This was the first step towards a plant expansion. There is now evidence that the traditional approach to reviewing and approving developments using the MDD may not be appropriate for the Collingwood Drinking Water System based on the recently verified winter disinfection limitations at the water treatment plant. Even though the traditional analysis using MDD shows that there is still sufficient capacity to supply some development while the water treatment plant expansion and upgrades are underway (Figure 1), a similar analysis using winter MDD (January 1 to March 31) demonstrates that the Collingwood Drinking Water System is already at, or exceeding, what would normally be considered a serviceable customer base when the target chlorine residual concentration is 1.9 mg/L in the winter and development with building permits already issued are factored into the water supply needs (Figure 2). In the absence of any other water treatment and/or disinfection upgrades, chlorine dosing will need to be increased beyond the current 1.9 mg/L dosing rate to ensure the disinfection requirements are achieved.


Figure 1 – Collingwood Drinking Water System Demands and Rated Treatment Capacity

Figure 2 – Winter Water Supply Demands and Existing Winter Treatment Capacity Remaining Available Water Supply Capacity Water supply capacity assessments are typically based on summer MDD when customers are filling pools and watering lawns; however, due to the limitations of the existing disinfection process at the Collingwood WTP in the winter months, a seasonal assessment of water demands now needs to be considered when determining the remaining available water supply capacity at the WTP. It is also important that staff consider a factor of safety on the available water supply capacity when committing to provide water servicing for a development to ensure that Collingwood can

79%

68%

78%82%

79%

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35,000

2016 2017 2018 2019 2020

Maxim

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Rated Water Treatment Plant Capacity (31,140 m3/day)

Winter Water Treatment Plant Capacity (19,872 - 20,995 m3/day)

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5,000

10,000

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25,000

2016 2017 2018 2019 2020

Wate

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Winter Treatment Capacity Winter Avg Day Demand Winter Max Day Demand


meet its actual water supply commitments beyond the theoretical calculations in these desktop analyses. Staff recommend that a minimum of five percent (5%) of the overall water treatment plant capacity be reserved (i.e. not committed to development) to ensure that all customers can be serviced during potentially unforeseen water demand situations until construction of the WTP expansion has commenced and risks can be managed within a firm timeline. Staff completed a comprehensive analysis of allocated drinking water supply. This included current water supply obligations to Collingwood users, New Tecumseth and Blue Mountains, water supply committed to Collingwood development through Building Permits and Conditional Building Permits, and a 5% factor of safety. The remaining water supply capacity in the Collingwood Drinking Water System ranges from 2,541 m3/day in the summer, to an overcommitment of 2,991 m3/day in the winter when a target chlorine residual of 1.9 mg/L is used (Table 4). This remaining available water supply capacity translates into 1,941 remaining development units (Single Dwelling Units, or SDUs) using the anticipated water demand associated with each type of development (Table 5) in the summer, or zero additional SDUs remaining in the winter. Table 4 – Remaining Available Water Supply Capacity, including Building Permits and Conditional Building Permits

Summer Capacity (m3/day)

Winter Capacity (m3/day)

Water Treatment Plant Capacity 31,140 19,872a

Town of New Tecumseth Current Purchase 9,500 9,500

Town of Blue Mountains Commitment 1,250 1,250

Collingwood Maximum Day Demand (Serviced) 15,630b 10,671c

Collingwood Committed Water Demand (Building Permits and Conditional Building Permits Issued but Not Fully Occupied)

662 449

Remaining Water Supply Capacity 4,098 -1,998

Remaining Water Supply Capacity with a 5% Factor of Safety

2,541 -2,991

Available SDUs 1,941 0

a Based on a target chlorine residual of 1.9 mg/L and a water temperature of 0.5oC b Actual maximum day demand recorded in Collingwood from January 1, 2016 – December 31, 2020 c Actual maximum day demand recorded in Collingwood between January 1 and March 31 from 2016 – 2020


Table 5 – Water Demands by Residential Development Type

Dwelling Type Average Demand

(m3/unit/day)1

Summer Maximum Demand

(m3/unit/day)1

Winter Maximum Demand

(m3/unit/day)2

SDU Equivalents

Single Detached 0.754 1.334 0.905 1.00

Semi-detached 0.702 1.242 0.842 0.93

Townhouse 0.624 1.104 0.749 0.83

Apartment 0.494 0.874 0.593 0.66

Although these calculations indicate that there is insufficient water supply to service existing customers and future development while waiting for the WTP expansion to be completed, there are solutions that can be implemented to mitigate the water supply capacity issue in the interim. These opportunities are discussed in detail below. Opportunities to Increase Available Water Supply Capacity Opportunity 1 – Water Treatment Plant Expansion and Upgrades When the maximum daily water supply demands at the Town’s water treatment plant exceeded eighty percent (80%) of the rated treatment capacity in 2019, the Town initiated a Municipal Class Environmental Assessment (EA) to expand and upgrade the treatment facility. The timing of this decision aligns with industry best management practices for initiating treatment expansion projects. The EA for the water treatment plant expansion and upgrades was completed in 2020 and identifies a Phase I expansion capacity of 51,871 m3/day. Staff have prepared a Request for Proposal (RFP) for engineering services to design, tender and provide construction administration services for the plant expansion, which is currently planned to be issued following the execution of a new water supply agreement with New Tecumseth. The existing project schedule forecasts the expanded water treatment plant will be completed and commissioned by the end of 2025. Staff understand the urgency of completing an agreement with New Tecumseth, and these negotiations are underway. In the broader context of the regional pipeline and the water supply agreement, there is a need to confirm the advantages to both municipalities and to refresh the Principles of Agreement to be executed in the legal agreement documents. As this negotiation is underway no new instruction to staff is proposed in this report. Opportunity 2 – Negotiate Temporary Water Supply Reductions with the Town of New Tecumseth and/or Town of the Blue Mountains Water supply agreements with neighbouring municipalities account for approximately thirty-five percent (35%) of the rated capacity of the water treatment plant. When the winter constraints of the disinfection infrastructure are taken into consideration, these commitments result in a commitment of over fifty percent (50%) of the treatment capacity of the water treatment plant. While these commitments will not be unreasonable when the expanded water treatment plant is

1 Based on the findings of the 2019 Water and Wastewater Master Servicing Plan. 2 Calculated using a winter Maximum Day Factor determined using the maximum daily water supply rate in the Town of Collingwood between January 1 and March 31 from 2016 through 2020.


commissioned, they make it challenging to service new development within the Town’s boundaries until that time. One option that could be pursued to increase the available drinking water treatment for Collingwood is a negotiated reduction in water supply commitment to these neighbouring municipalities. A reduction of 500 m3/day to each municipality (for a total reduction of 1,000 m3/day) would result in an additional 750 SDUs available year-round to the Town of Collingwood prior to the completion of the expansion of the WTP. A reduction in drinking water supply to Blue Mountains and/or New Tecumseth will require coordination with the respective municipalities. The water supply agreement between Collingwood and Blue Mountains does not have an end date therefore Collingwood may need to use the exit clause in the agreement to terminate or reduce this water supply commitment. The water supply agreement between Collingwood and New Tecumseth expired in May 2020 and is still being renegotiated. As there is currently no legal agreement to supply water to New Tecumseth, a reduced supply commitment to New Tecumseth until the expansion is complete is something that can be sought through negotiation. Staff acknowledge that a reduction in the sale of water to neighbouring municipalities at the volumes outlined above is insufficient to overcome the winter water treatment capacity deficit, but this opportunity could form part of a larger solution to address the water supply limitations. Opportunity 3 – Increase Chlorine Dosing During Winter (Use Existing Chlorine Contact Infrastructure) With a current chloring dosing rate of 1.9 mg/L during the winter, an average chlorine residual of 1.85 mg/L is entering the distribution system; however, these concentrations are being detected as high as 2.73 mg/L due to additional chlorine from a membrane cleaning process. The chlorine dosing rate is manually adjusted by the water treatment operators based on the raw water quality and anticipated water supply demands to ensure that the required disinfection of the drinking water occurs. If winter water supply demands are anticipated to increase based on approved development, the water treatment operators will be required to increase the chlorine dosing rate to ensure that adequate disinfection continues to occur. Potential winter treatment capacity ranges based on increasing the target chlorine residual up to 2.2 mg/L are provided in Table 6. Table 6 – Winter Treatment Capacity with Varying Target Chlorine Residuals

Target Chlorine Residual Winter Minimum Capacity

(m3/day)a

1.90 mg/L 19,872

2.00 mg/L 21,168

2.10 mg/L 22,636

2.20 mg/L 24,019

a Based on a water temperature of 0.5 oC

A concern with increasing chlorine dosing to increase the available treatment capacity is the resulting effects in distribution water quality. Noting that chlorine concentrations are not to exceed 4 mg/L in the water distribution system at any time, and that there are already chlorine concentration spikes as high as 2.73 mg/L, any increase to the current chlorine dosing of 1.90 mg/L will put the Town at greater risk of exceeding this 4.0 mg/L limit and even further above the recommended 0.2 mg/L chlorine concentration in the distribution system. Although a slight increase to the chlorine dose (with residual concentrations remaining less than 4.0 mg/L) is not a


drinking water quality health and safety issue, any increase to the current chlorine dosing rate will result in more taste and odour complaints from consumers. An increase in chlorine dosing will also increase the hazard risk for the drinking water operators who need to work in the open tank facility and are exposed to the chlorine fumes, and it will increase damage to the water treatment equipment due to the corrosiveness of the higher concentrations of chlorine. An increase to the chlorine dosing rate should only be considered as a temporary measure to increase in water supply demands through the winter months while a long-term solution is implemented. Appropriate chlorine dose increases would be managed by the water treatment operators to ensure adequate disinfection is achieved for increased drinking water supply needs. Chlorine dosing could increase beyond the 2.2 mg/L outlined above if necessary. However, higher chlorine doses will result in further impairment to the drinking water aesthetic quality, increased risk of chlorine exposure to the water treatment operators, and a greater potential of exceeding the 4 mg/L upper limit for chlorine in the water distribution system. Opportunity 4 – Improvements to Existing Disinfection Infrastructure A long-term solution to achieving the required disinfection for an increased water supply through the winter is an upgrade to the existing disinfection process. Through an assessment of options available, staff have further investigated the following options:

a. Additional chlorination in the intake pipe; b. Constructing a new chlorine contact tank to provide additional contact time for higher

flows; c. Heating the untreated water to reduce chlorine contact tank volume requirements during

the winter; and d. Adding temporary filtration units.

These options are discussed in further detail below. Opportunity 4A - Chlorination at the Intake Pipe Scope and Benefits: The ability to chlorinate the raw water at the treatment plant intake currently exists. The capacity of this chemical system is limited as its current approved use is for the seasonal control of zebra mussels only. Increasing the chlorination at the intake will provide for the ability to use the intake pipe for additional chlorine contact time for disinfection. This time will be added to the time that is achievable in the existing chlorine contact tanks, thus reducing the chloring dosing requirements in the contact tanks while achieving the disinfection requirements. A minimum chlorine contact time for disinfection is required to meet the requirements of the Town’s MECP approvals and the Provincial Drinking Water Quality Standards. The capacity, robustness and redundancy of the chlorination system would need to be increased and additional approvals from the MECP would be required in the form of a license and permit amendment as this will change the chlorine concentration-time (CT) calculation, chlorination system and residue management. While the Procedure for Disinfection of Drinking Water in Ontario discourages this practice as disinfection of unfiltered water is less effective, the MECP


has permitted other older water treatment plants to incorporate this approach to disinfection as an alternative to a major plant upgrade. This option would allow the plant to operate at its full rated capacity of 31,140 m3/d under all temperature and raw water conditions while providing the required disinfection by chlorination without increasing the potential for taste and odour concerns by customers. Concerns and Constraints: Using the intake pipe for pre-treatment chlorine disinfection comes with several challenges. Many of these relate to controlling the system given the distance from the plant to the end of the intake pipe (approximately 750m). The chlorination system will have to be updated to include flow pacing capability for the pre-chlorination system. The distance from the plant to the injection point, the location of a potential sample point and the distance from the sample point to the chlorine analyzer and chlorinator that will be located in the plant all negatively impact the responsiveness of the system and the ability of operations to respond to changing water quality conditions. To meet the anticipated MECP requirements of this proposed system for source water protection, residue management (outflow of filter backwash concentrate to lake) will now require a dechlorination system and another analyzer to confirm absence of chlorine residual. It is noted that the MECP does not encourage this type of chlorination arrangement, hence approvals may be challenging to obtain. This year the plant experienced a frazil ice blockage and the intake. Part of correcting this was to reverse the flow in the intake to push the ice out. If the intake is used for chlorination and the flow needs to be reversed to address a frazzle ice issue, this will push chlorinated water into the lake and may require a reporting to the Spills Action Centre (MECP). Typically, chlorine is dosed after filtration as one of the final steps in the treatment process. Adding chlorine at levels appropriate for disinfection at the intake will mean there will be chlorine present in the open filter beds within the plant, increasing chlorine in atmosphere which will cause equipment to corrode more quickly and increase chlorine exposure to operators. Elevated chlorine levels in the filter tanks will cause other operational challenges such as foaming and elevated THM (a negative disinfection by-product and water quality issue) levels in the treated water. Lastly, once the plant expansion is complete this system will no longer be required and would be decommissioned resulting in a large throw away cost. Costs: The estimated cost to move forward with this option is $300,000 (approximately $50,000 in engineering fees and approximately $250,000 in contractor and equipment costs). Schedule: Design and MECP approvals could take 6-8 months. Construction, commissioning and start up would likely take another 6-8 months.


Opportunity 4B - Advanced Construction of the New Chlorine Contact Tank Scope and Benefits: A conceptual design for a new chlorine contact chamber was completed as part of the GHD analysis in 2019 and was further refined as part of the EA process for the plant expansion. This alternative is based on the construction of a new, below grade chlorine contact chamber that would operate in series with the two existing chambers until the proposed treatment plant expansion is complete. Ultimately this new tank would provide for all the chlorine contact time requirements associated with the expanded facility when it is combined with the UV disinfection proposed as part of the treatment plant expansion project. Modifications to some of the internal process piping would be required as well as some additional yard piping to integrate this chamber into the existing plant. To the greatest extent possible any constructed works would be designed to be utilized as part of the plant expansion, reducing any throw away costs. This option would allow the plant to operate at its full rate capacity of 31,140 m3/d under all temperature and raw water conditions while providing the required disinfection by chlorination without increasing the potential for taste and odour concerns by customers. Concerns and Constraints: There is a significant amount of buried infrastructure immediately surrounding the WTP building, which would make it difficult to install a new tank adjacent to the two existing contact chambers. The new tank would likely need to be constructed in the grassy area to the north of the WTP building as described in the EA documentation. The location, footprint, and elevation of the new chlorine contact chamber would be confirmed during preliminary and detailed design, and hydraulic analysis would be required to assess the impact on the operation of the existing plant. Increasing the distance between the location of new tank and the WTP building may also help protect the WTP Building from damage during construction, since blasting would likely be required due to the shallow bedrock elevation at the site. Construction will require a temporary shutdown of the WTP. Significant planning will be required during design and construction to ensure appropriate measures are taken to minimize the duration of the shutdown, and the impact of construction activities on WTP performance. Bedrock is present at a relatively shallow depth at the site, so blasting would be required during construction. Appropriate measures would need to be taken to ensure blasting activities do not have an impact on existing WTP infrastructure and neighbouring properties. Costs: The estimated cost to expand the chlorine contact tank is approximately $4,000,000. The majority of this cost will be spent through the WTP expansion project anyway if this project is not advanced ahead of time. Schedule: The RFP for engineering services for the plant expansion is ready to issue for tender. The design and approvals for the expansion are expected to take 18 months and construction is anticipated to take approximately three years. Requirements could be put on the design engineers to fast track the design and possibly tendering and construction of the proposed new chlorine tank which would allow it to be in service as soon as two years after award of the design contract.


Opportunity 4C – Heating the Untreated Water Scope and Benefits: As the disinfection capacity at the WTP is constrained by the winter temperatures of the water being treated, one interim option that staff have considered is to increase the available water supply capacity by heating the untreated water using either electric or natural gas heaters at the WTP. This would reduce the amount chlorine necessary to achieve the required disinfection by chlorination during the winter months, and consequently reduce or eliminate the concerns previously identified with increasing chlorine dosing above the current rate of 1.9 mg/L. Concerns and Constraints: Concerns related to this alternative are the structures or space required to house all infrastructure and consideration that all components of this alternative would not be utilized within the proposed plant expansion. Natural gas or electrical supply upgrades would also be required. Schedule: Staff anticipate it would take approximately two years to design, obtain necessary MECP approvals and install a heating system at the WTP. Costs: Assuming the water can be heated fast enough, staff estimate that 145,000 kW would be required to heat 31,100 m3/d of water from a temperature from 1oC to 5oC. At an assumed electricity price of $0.12/kWh, which is conservative, it would cost approximately $17,400/day to heat the water. If this level of heating is required from January 1 through March 31 each year, the operating costs alone of this option would be in the range of $1,500,000 per year. The Town would also need to purchase, install and maintain a 6,000 kW heat source to support this initiative, which would become obsolete once the WTP expansion is complete. Opportunity 4D – Additional Temporary Filtration Units Scope and Benefits: Temporary portable membrane treatment modules were investigated as an option to provide additional treatment capacity at the WTP. These units are generally intended for small water demand scenarios such as mining camps or isolated small communities with limited demands. They are housed in portable structures similar to shipping containers and can provide some limited small scale water treatment capacity either as standalone processes or integrated into larger systems. While these units would provide some additional filtration capacity to supplement the existing treatment plants membranes, additional chlorine disinfection capacity would still be required as discussed previously; therefore, Opportunity 4A or 4B would need to be implemented with this opportunity.


Concerns and Constraints: While portable membrane filtration units could provide some temporary additional treatment capacity, they do come with limitations and some challenges that at this time do not appear worth the cost and the additional capacity that would be attained. These units, while modular in construction are generally custom ordered and built to specific customer requirements. A design would need to be completed and then approvals would be required from the MECP for their use as well as for any increase in rated capacity for the WTP. Upon commissioning of the expanded WTP, these units would no longer be useful and would need to be disposed of. Schedule: Staff estimate that the design, approvals, procurement and installation of temporary filtration units would take, at a minimum, 18-24 months. Opportunity 5 – Revise Existing and Develop New Planning Policies to Manage Available Drinking Water Supply Capacity The Town should also consider implementing tools to manage any water supply capacity that remains available through the Planning Act and Planning Policies. Further details about options and Planning tools are provided in report P2021-12. Opportunity 6 – Do Nothing A final opportunity that needs to be considered is that Collingwood acknowledge that there is no remaining water supply capacity available to service new development until the water treatment plant expansion is complete. This opportunity would also require the creation of new planning policies to stop new development. Opportunities Analysis The ultimate solution to the drinking water treatment capacity issue is the water treatment plant expansion and upgrade project that is due to be completed in the next five (5) years (Opportunity 1). The schedule for this project is at a critical point. To ensure the successful completion of the WTP expansion by the end of 2025, staff recommend obtaining legal advice about approaching New Tecumseth to share costs and risks associated with issuing the RFP ahead of the new water supply agreement, such that the engineering design can be commenced. While the WTP expansion project advances, a combination of the other opportunities presented above will allow the Town to provide some water supply allocation to proposed development until the expanded WTP is commissioned. Opportunity 3 (increasing chlorine dosing) offers a quick solution to the immediate drinking water supply capacity limitations and is carried forward in this analysis. In addition to Opportunity 3, negotiating reduced winter water supply commitments (Opportunity 2) with the Blue Mountains and New Tecumseth will free up some additional capacity to service


development and/or mitigate the requirement to increase chlorine dosing while the WTP expansion is underway. If the Town requires additional water supply capacity for development prior to the completion of the WTP expansion beyond what can be achieved through renegotiation of the municipal water supply agreements and increased chlorine dosing, upgrades to the existing disinfection infrastructure should be implemented (Opportunity 4). The addition of chlorination (Opportunity 4A) at the intake comes with several risks, difficult approvals, operational challenges and limitations. While the capital cost investment for this solution is lower than Opportunity 4B, it results in a solution that will be abandoned when the plant is expanded. Similar challenges exist for the heating of water (Opportunity 4C) and additional portable filtration units (Opportunity 4D). The construction of a new chlorine contact chamber (Opportunity 4B) is the preferred approach to increasing the disinfection capacity at the WTP. Staff acknowledge that this option has high upfront capital costs; however, there would be very limited throw away costs as this infrastructure is part of the plan for the overall WTP expansion that will ultimately be built. A comparison of the resulting impacts on water supply requirements and available drinking water treatment capacities for Opportunities 2 through 4 are provided in Appendix A to this report, as well as Figures 3 and 4.

Figure 3 – Opportunities Analysis for Summer Water Demands and Treatment Capacity


Figure 4 – Opportunities Analysis for Winter Water Demands and Treatment Capacity While the implementation of Opportunity 2, Opportunity 3 and/or Opportunity 4B is underway, staff also recommend that existing Planning policies are revised and/or new Planning policies are developed to manage both the available drinking water supply and wastewater treatment plant capacities (Opportunity 5)

5. EFFECT ON TOWN FINANCES

Implementation of the recommended short term and long-term actions to increase the available water treatment supply capacity until the WTP expansion is complete could have various financial impacts, including increased operational expenses (chemical and equipment replacement), reduced revenue from water sales to other municipalities and capital project costs as noted in this report if capital improvements are required to increase the available water supply capacity. The recommended options can be carried out within the current funding envelopes available, and pending Council endorsement and agreements, some capital costs may be shared with other municipalities under their water purchase agreements.

6. CONSIDERATIONS

Community Based Strategic Plan: ☐ N/A or ☒ Explain: Choose an item.


Climate Change / Sustainability: ☒ N/A or ☐ Explain: Choose an item.

Accessibility: ☒ N/A or ☐ Explain: Choose an item.

Communication / Engagement: ☒ N/A or ☐ Explain: Choose an item.

Accountability / Transparency: ☐ N/A or ☒ Explain: Enhances Accountability and

Transparency

Appendix A Available Water Treatment Capacity by Opportunity

SIGNATURES

Prepared by: Department Head:

Heather McGinnity Manager of Environmental Services

Peggy Slama Director of Public Works, Engineering &

Environmental Services

Town of Collingwood Town of Collingwood

7. APPENDICES & OTHER RESOURCES


Appendix A Available Water Treatment Capacity by Opportunity

Appendix A - Available Water Treatment Capacity by Opportunity

Opportunity 1 Opportunity 2 Opportunity 2 Opportunity 3 Opportunity 3Opportunity 1

Summer & Winter Summer Winter Summer WinterTown of Blue Mountains 1,250 1,250 1,250Town of New Tecumseth 9,500 9,500 9,500Town of Blue Mountains (Reduced) 750 750Town of New Tecumseth (Reduced) 9,000 9,000Town of Collingwood MDD 15,630 15,630 15,630Town of Collingwood Winter MDD 10,671 10,671Summer Commited (Building Permits)* 662 662 662Winter Commited (Building Permits)* 449 449Rated Treatment Capacity 31,140 31,14095% Rated Treatment Capacity 29,583 29,583Winter Treatment Capacity (1.9 mg/L) 19,87295% Winter Treatment Capacity (1.9 mg/L) 18,878Winter Treatment Capacity (2.2 mg/L) 24,01995% Winter Treatment Capacity (2.2 mg/L) 22,818Expanded Water Treatment Plant Capacity 51,87195% Expanded Water Treatment Plant Capacity 49,277Remaining Treatment Plant Capacity 24,829 5,098 0 4,098 2,149Remaining Treatment Plant Capacity with Factor of Safety 22,235 3,541 0 2,541 948Remaining SDUs 18,612 3,822 0 3,072 2,375Remaining SDUs with Factor of Safety 16,668 2,654 0 1,905 1,048

* Includes Building Permits issued but not occupied, Conditional Building Permits, and Building Permit applications under review

Opportunity 3Opportunity 2

Appendix A - Available Water Treatment Capacity by Opportunity

Town of Blue MountainsTown of New TecumsethTown of Blue Mountains (Reduced)Town of New Tecumseth (Reduced)Town of Collingwood MDDTown of Collingwood Winter MDDSummer Commited (Building Permits)*Winter Commited (Building Permits)*Rated Treatment Capacity95% Rated Treatment CapacityWinter Treatment Capacity (1.9 mg/L)95% Winter Treatment Capacity (1.9 mg/L)Winter Treatment Capacity (2.2 mg/L)95% Winter Treatment Capacity (2.2 mg/L)Expanded Water Treatment Plant Capacity95% Expanded Water Treatment Plant CapacityRemaining Treatment Plant Capacity Remaining Treatment Plant Capacity with Factor of SafetyRemaining SDUsRemaining SDUs with Factor of Safety

* Includes Building Permits issued but not occupied, Conditional Building Permits, and Building Permit applications under review

Opportunity 2 & 3Opportunity 2 & 3Opportunity 4B Opportunity 4B

Summer Winter Summer Winter1,250 1,2509,500 9,500

750 7509,000 9,000

15,630 15,63010,671 10,671

662 662449 449

31,140 31,140 31,14029,583 29,583 29,583

24,01922,818

5,098 3,149 4,098 9,2703,541 1,948 2,541 7,7133,822 3,480 3,072 10,2432,654 2,153 1,905 8,523

Opportunity 4BOpportunity 2 & 3

staff report #pw2021-09

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