ICMP RIP OSPF EGP 5 Red IP ARP I RARP

The Sutton WPCP is a sequencing batch reactor (SBR) with continuous backwash, upflow sand filters. The facility is owned and operated by the Regional Municipality of York. The Sutton WPCP has a CofA rated ADF capacity of 3,412 m3/d.

Wastewater is pumped into the headworks upstream of grit removal. The headworks consist of two vortex grit chambers followed by screening through a mechanical

filter screen (or a manually raked bar screen used for by-pass). Preliminary treated wastewater flows to the two intermittent cycle extended aeration (ICEAS) type SBR's and then to the secondary effluent equalization tank. SBR effluent undergoes sand filtration in a continuous backwash, upflow sand filter and is disinfected with UV irradiation prior to discharge to a tributary of the Black River, which discharges to Lake Simcoe.

WAS is stored in an aerated sludge holding tank and then dewatered before being shipped to the Duffin Creek WWTP for further processing.

Phosphorus removal at the Sutton WPCP is achieved by chemical precipitation using alum and tertiary filtration. Alum is dosed at the inlet to the SBR's and again at the pumps which feed to the final filters. There are three chemical metering pumps (2 duty, one standby) pumping from the alum storage tank. Alum dosing is flow paced.

Figure 3.11 presents a process flow diagram of the treatment process at the Sutton WPCP. Vortex Grit Removal SBR #1 SBR #2 Mechanically Cleaned Bar Screen Thickened Sludge To Duffin’s Creek Raw Wastewater Alum to SBR Inlet WAS

Sutton WPCP Process Flow Diagram

UV Disinfection Effluent To Black River Tertiary Filtration Alum to SBR Inlet Sludge Thickening Tank Aerated Sludge Storage Alum Manually Cleaned Bar Screen

Figure 3.11 Sutton WPCP Process Flow Diagram

3.6.1 Performance Requirements

The Sutton WPCP operates under CofA Number 0693-75HJ7R and has a rated ADF capacity 3,412 m3/d. The effluent TP objectives and limits for the Sutton WPCP are presented in Table 3.22. Included in the table is the interim annual phosphorus loading limit as outlined in O. Reg. 60/08 and amended in O. Reg. 130/09.

Table 3.22 Certificate of Approval and Interim Effluent Phosphorus Objectives and Limits for the Sutton WPCP

Parameter Effluent Objective Effluent Limit (1) Interim Annual

Loading Limit (2) Effluent TP Concentration 0.13 0.18 mg/L n/v Effluent TP Loading n/v 0.61 kg/d (224 kg/yr) 148 kg/yr Notes: n/v – no value

1. Limits based on monthly average concentrations.

2. Based on O. Reg. 60/08 and later amended by O. Reg. 130/09.

3.6.2 Historical Performance

The historic operating performance of the Sutton WPCP with respect to phosphorus removal is presented in Table 3.23.

Table 3.23 Historic Phosphorus Removal at the Sutton WPCP

Parameter 2006 2007 2008 Overall

ADF (m3/d) 1,467 1,375 1,798 1,547

Raw Sewage TP Concentration (mg/L) 4.4 3.4 3.9 3.9

Raw Sewage TP Loading (kg/d) 6.5 4.7 7.0 6.0

Effluent TP Concentration (mg/L) 0.07 0.06 0.13 0.09

Effluent TP Loading (kg/d) 0.10 0.08 0.23 0.13

Annual Effluent TP Loading (kg/yr) 37.5 30.1 85.5 51.0

Phosphorus Removal (kg/d) 6.4 4.6 6.8 5.9

Total Phosphorus Removed (kg) 2,319 1,677 2,480 4,799 (1)

Operating Costs (CAD) $27,843 $44,677 $28,391 $56,234 (1)

Cost/kg TP Removed (CAD/kg TP) $12.01 $26.65 $11.45 $11.72 (2)

Notes:

1. Two year total based on 2006 and 2008 data.

2. Based on two year total Operating Costs divided by two year Total Phosphorus Removed.

In 2006 and 2007, the effluent TP concentration from the Sutton WPCP was below the effluent objective of 0.13 mg/L. In 2008, the ADF increased by nearly 30 percent. Coupled with an increase in TP strength of nearly 200 percent, the average annual effluent TP concentration increased to 0.13 mg/L, which is lower than the compliance limit of 0.18 mg/L. The plant was not in compliance with effluent TP limits in July and August of 2008. Over the period from 2006 to 2008, the annual effluent TP loadings were below the interim limit of 148 kg/yr.

The three year average effluent TP concentration from the Sutton WPCP is 0.09 mg/L. From 2006 to 2008, approximately 6,476 kg of phosphorus were removed. It should be noted that over this period, the Sutton WPCP has historically operated at approximately 45 percent of the CofA rated ADF capacity. As the flows to the plant approach the design capacity, the effluent phosphorus loading may increase. In 2007, chemical costs were nearly double the amount in each of the other two years reviewed. The cause of this increase is uncertain. As a result, data from 2007 will not be included in the overall historical unit removal costs. The effective unit removal cost for the Sutton WPCP for 2006 and 2008 was $11.72 CAD/kg TP removed.

3.6.3 Upgrades to the Existing Facility to Achieve Effluent TP Objective

Concentrations of 0.10 mg/L

The Sutton WPCP is a secondary treatment facility with tertiary filtration. Past experience with secondary treatment facilities with tertiary filtration has indicated that effluent TP concentrations as low as 0.1 mg/L can be consistently achieved (Ross et al., 1991). Historically, the Sutton WPCP has achieved an average effluent TP concentration of 0.09 mg/L. Therefore, it is anticipated that no further upgrades will be necessary to consistently achieve an effluent TP objective concentration of 0.10 mg/L. As the flows to the plant approach the design capacity, optimization of chemicals and chemical addition stra tegies will likely be required in order to maintain the performance of the phosphorus removal system at the Sutton WPCP.

3.6.4 Upgrades to the Existing Facility to Achieve Effluent TP Objective

Concentrations of 0.05 mg/L

Conceptual level upgrades to the Sutton WPCP were developed for the replacement of the existing tertiary filtration with membrane ultrafiltration. Table 3.24 presents the incremental costs associated with upgrading the Sutton WPCP to membrane ultrafiltration. Included in the table are annual O&M costs and a 25-year life cycle cost.

Table 3.24 Incremental Costs to Upgrade to Membrane Ultrafiltration for the Sutton WPCP

Parameter Summary

Capital Cost (CAD) $3,810,000

Annual O&M Costs (CAD) $190,000/yr

25-Year Life Cycle Cost (1) (CAD) $6,520,000

Additional TP Removed Annually (2) 62 kg/yr

Total Additional TP Removed (25-yr Total) 1,557 kg

Cost/kg TP Removed (CAD) $4,189/kg TP removed

Notes:

1. Calculated based on an inflation rate of 2.5 % and an interested rate of 7.5%.

2. Additional mass of TP removed at its CofA rated capacity based on a projected effluent TP concentration of 0.10 mg/L for a secondary treatment plant with tertiary filters and 0.05 mg/L after the installation of membrane ultrafiltration.

Upgrading the Sutton WPCP to membrane ultrafiltration will cost an estimated $3.8M CAD with annual operating costs of approximately $190K CAD/yr. The 25- year life cycle cost is approximately $6.5M CAD. The addition of membrane ultrafiltration is projected to result in an annual reduction of approximately 62 kg TP/yr. Over 25 years, this results in a total reduction in effluent TP loading of 1,557 kg. Based on the 25-year life cycle cost, the cost per additional kg of TP removed is estimated to be $4,189 CAD/kg TP.

3.6.5 Summary of Conceptual Level Upgrade Costs

Based on the current configuration of the Sutton WPCP, no capital upgrades would be required in order to consistently achieve an effluent TP objective concentration of 0.10 mg/L. In order to consistently reduce effluent TP concentrations to 0.05 mg/L, membrane ultrafiltration would have to be installed. Figure 3.12 presents a side-by- side comparison of the historic cost per kg of TP removed based on information for 2006 and 2008, and the cost per additional kg of TP removed as a result of the conceptual level upgrades.

Figure 3.12 Unit Removal Costs for the Sutton WPCP

The cost per kg of TP removed as a result of the upgrades to membrane ultrafiltration is approximately 350 times the historic (2006 and 2008) unit removal cost.