RELLENOS

The Lagoon City STP is an extended aeration plant located in Ramara Township, and services Lagoon City and the community of Brechin. The facility is owned and operated by the Corporation of the Township of Ramara and has a CofA rated ADF capacity of 2,273 m3/d.

The existing works consist of a septage receiving station with manually cleaned bar screen and two septage equalization holding tanks. Two degritting channels are used to remove sand and silt, followed by a bar screen for the removal of larger solids. An inlet splitter box controls the flows of preliminary treated wastewater to the three earthen aeration basins. The basins are designed with sufficient freeboard to allow for buffering capacity during high flows, and maintaining low peak flows to the secondary clarifiers. From the aeration tank, mixed liquor is pumped to the three secondary clarifiers via screw pumps. Clarified effluent is disinfected with UV irradiation prior to discharge to a wetland area, which discharges into Lake Simcoe. Waste sludge is digested in a two-stage aerobic digester and stored in a 763 m2 storage tank prior to land application.

Phosphorus removal at the Lagoon City STP is achieved by chemical precipitation using alum and polymers in the clarifiers.

Figure 3.27 presents a process flow diagram of the treatment process at the Lagoon City STP. Degritting Channels Aeration Tank #1 Aeration Tank #2 Secondary Clarifier #1 Mechanically Cleaned Bar Screen Raw Wastewater RAS WAS

Lagoon City STP Process Flow Diagram

UV Disinfection Effluent To Lake Simcoe Secondary Clarifier #2

Alum and Polymer to Secondary Clarifiers Manually Cleaned Bar Screen Septage Septage Holding Tanks Aeration Tank #3 Land Application Aerated Sludge Storage

Alum and Polymer to Secondary Clarifiers

Secondary Clarifier #3

Aerobic Digestion

Figure 3.27 Lagoon City STP Process Flow Diagram

3.14.1 Performance Requirements

The Lagoon City STP operates under CofA Number 1114-745MQT and has rated ADF capacity of 2,273 m3/d. The effluent TP objectives and limits for the Lagoon City STP are presented in Table 3.50. 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 3.50 Certificate of Approval and Interim Effluent Phosphorus

Objectives and Limits for the Lagoon City STP

Parameter Effluent Objective Effluent Limit Interim Annual

Loading Limit (2)

Effluent TP Concentration 0.24 0.3 mg/L (1) n/v

Effluent TP Loading n/v 249 kg/yr (3) 200 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. Limits based on total annual loading.

3.14.2 Historical Performance

The historic operating performance of the Lagoon City STP with respect to phosphorus removal is presented in Table 3.51.

Table 3.51 Historic Phosphorus Removal at the Lagoon City STP

Parameter 2006 2007 2008 Overall

ADF (m3/d) 1,446 1,317 1,575 1,446

Raw Sewage TP Concentration (mg/L) 1.3 1.4 1.2 1.3

Raw Sewage TP Loading (kg/d) 1.9 1.8 1.9 1.9

Effluent TP Concentration (mg/L) 0.10 0.07 0.07 0.08

Effluent TP Loading (kg/d) 0.14 0.09 0.11 0.12

Annual Effluent TP Loading (kg/yr) 52.8 33.6 40.4 42.3

Phosphorus Removal (kg/d) 1.7 1.8 1.8 1.8

Total Phosphorus Removed (kg) 633 639 651 1,924 (1)

Operating Costs (CAD) $31,357 $23,564 $33,056 $87,977 (1)

Cost/kg TP Removed (CAD/kg TP) $49.51 $36.86 $50.75 $45.72 (2)

Notes:

1. Three year total.

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

The three year average effluent TP concentration from the Lagoon City STP is 0.08 mg/L. This is below the TP effluent objective of 0.24 mg/L. Over the period from 2006 to 2008, the effluent TP objective was not exceeded. Over the same period, the annual effluent TP loadings were below the interim limit of 200 kg/yr.

From 2006 to 2008, approximately 1,924 kg of phosphorus were removed at a cost of $87,977. The effective unit removal cost for the Lagoon City STP was $45.72 CAD/kg TP removed. In 2007, chemical costs were approximately 70 percent of that in each of the other two years.

3.14.3 Upgrades to the Existing Facility to Achieve Effluent TP Objective Concentrations of 0.10 mg/L

The Lagoon City STP is currently a secondary treatment plant with chemical addition for phosphorus removal. Operating historically at approximately 64 percent of the CofA rated ADF capacity, the plant has been able to achieve an average effluent TP concentration of 0.08 mg/L. Typically, secondary treatment facilities can consistently achieve effluent TP concentrations as low as 0.30 mg/L without tertiary filtration, and it is anticipated that as the flows to the Lagoon City STP approach the CofA rated capacity, the effluent TP concentration may increase. In order to reduce the anticipated phosphorus loading from the Lagoon City STP at CofA rated capacity, conceptual level upgrades were developed for the Lagoon City STP.

Based on the existing phosphorus removal strategy at the Lagoon City STP, upgrading the facility by the addition of tertiary filtration would effectively reduce the anticipated effluent TP from 0.30 mg/L to 0.10 mg/L.

Table 3.52 presents the incremental costs associated with upgrading the Lagoon City STP to secondary treatment with tertiary filtration. Included in the table are annual O&M costs and a 25-year life cycle cost.

Table 3.52 Incremental Costs to Upgrade to Tertiary Filtration for the

Lagoon City STP

Parameter Summary

Capital Cost (CAD) $1,100,000

Annual O&M Costs (CAD) $10,000/yr

25-Year Life Cycle Cost (1) (CAD) $1,200,000

Additional TP Removed Annually (2) 166 kg/yr

Total Additional TP Removed (25-yr Total) 4,148 kg

Cost/kg TP Removed (CAD) $300/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 0.30 mg/L for a secondary treatment plant and an effluent TP of 0.10 mg/L for a secondary treatment plant with tertiary filters.

Upgrading the Lagoon City STP to include tertiary filtration will cost an estimated $1.1M CAD with annual operating costs of approximately $10K CAD/yr. The 25- year life cycle cost is approximately $1.2M CAD. The addition of tertiary filtration is projected to result in an annual reduction of approximately 166 kg TP/yr. Over 25 years, this results in a total reduction in effluent TP loading of 4,148 kg. Based on the 25-year life cycle cost, the cost per additional kg of TP removed is estimated to be $300 CAD/kg TP.

3.14.4 Upgrades to the Existing Facility to Achieve Effluent TP Objective Concentrations of 0.05 mg/L

Conceptual level upgrades to the Lagoon City STP were developed for the installation of membrane ultrafiltration to achieve effluent TP objective concentrations of 0.05 mg/L. Table 3.53 presents the incremental costs associated with upgrading the Lagoon City STP to membrane ultrafiltration. Included in the table are annual O&M costs and a 25-year life cycle cost.

Table 3.53 Incremental Costs to Upgrade to Membrane Ultrafiltration for the Lagoon City STP

Parameter Summary

Capital Cost (CAD) $2,770,000

Annual O&M Costs (CAD) $140,000/yr

25-Year Life Cycle Cost (1) (CAD) $4,800,000

Additional TP Removed Annually (2) 207 kg/yr

Total Additional TP Removed (25-yr Total) 5,185 kg

Cost/kg TP Removed (CAD) $919/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 0.30 mg/L for a secondary treatment plant and 0.05 mg/L after the installation of membrane

ultrafiltration.

Upgrading the Lagoon City STP to membrane ultrafiltration will cost an estimated $2.8M CAD with annual operating costs of approximately $140K CAD/yr. The 25- year life cycle cost is approximately $4.8M CAD. The addition of membrane ultrafiltration is projected to result in an annual reduction of approximately 207 kg TP/yr. Over 25 years, this results in a total reduction in effluent TP loading of 5,185 kg. Based on the 25-year life cycle cost, the cost per additional kg of TP removed is estimated to be $919 CAD/kg TP.

3.14.5 Incremental Costs to Upgrade to Membrane Ultrafiltration

Upgrading to membrane ultrafiltration will result in improved phosphorus removal compared to upgrading with tertiary filtration. At the same time, the capital and O&M costs for membrane ultrafiltration will be higher than those for tertiary filtration. Table 3.54 presents the incremental costs associated with upgrading the Lagoon City STP to membrane ultrafiltration instead of tertiary filtration. Included in the table are annual O&M costs and a 25-year life cycle cost.

Table 3.54 Incremental Costs to Upgrade to Membrane Ultrafiltration Instead of Tertiary Filtration for the Lagoon City STP

Parameter Summary

Capital Cost (CAD) $1,670,000

Annual O&M Costs (CAD) $130,000/yr

25-Year Life Cycle Cost (1) (CAD) $3,520,000

Additional TP Removed Annually (2) 41 kg/yr

Total Additional TP Removed (25-yr Total) 1,037 kg

Cost/kg TP Removed (CAD) $3,399/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 to membrane ultrafiltration instead of conventional tertiary filtration would result in improved phosphorus removal of 41 kg TP/yr. Over 25 years, this would result in an increase in total phosphorus removal of 1,037 kg. Upgrading to membrane ultrafiltration instead of conventional tertiary filtration comes at an additional capital cost of $1.7M CAD, O&M costs that are nearly 14 times greater, and a 25-year life cycle cost that is approximately $3.5M CAD greater. Incrementally, the improved phosphorus removal achieved as a result of membrane ultrafiltration over conventional tertiary filtration would come at a unit removal cost of $3,399 CAD/kg TP. This incremental unit removal cost is much higher than the incremental unit removal cost associated with the upgrade to tertiary filtration. Over a 25-year life cycle, upgrading to membrane ultrafiltration would result in an increase in TP removal of about 20 percent at nearly 4 times the 25-yr life cycle cost of the upgrade to tertiary filtration. Subsequently, the incremental cost per unit of TP removed as a result of upgrading to membrane ultrafiltration is significantly higher than for the upgrade to tertiary filtration.

3.14.6 Summary of Conceptual Level Upgrade Costs

Based on the current configuration of the Lagoon City STP, upgrade to tertiary filtration would allow the facility 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 3.28 presents a side-by-side comparison of the historic cost per kg of TP removed and the cost per additional kg of TP removed as a result of the conceptual level upgrades.

Figure 3.28 Unit Removal Costs for Lagoon City STP

Of the options evaluated, construction of conventional tertiary filters is the most economical upgrade option to reduce TP loading from the Lagoon City STP. Upgrade to tertiary filtration would result in significantly lower capital, O&M, 25- year life cycle, and unit removal costs than upgrading to membrane ultrafiltration. The cost per additional kg of TP removed as a result of upgrading from conventional tertiary filtration to membrane ultrafiltration is $3,399 CAD/kg TP.

3.15 Summary of Historical Phosphorus Removal Performance and