South End Water Pollution Control Centre (SEWPCC) project upgrades
The SEWPCC has three stages of wastewater treatment:
- Primary treatment
- Secondary treatment
- An ultraviolet effluent disinfection process that operates on a seasonal basis from May 1 through September 30
One major expansion is planned for the SEWPCC. Biological nutrient removal (BNR) will be added to a planned expansion of the secondary treatment process.
Expansion of the secondary treatment process will take place at the same time as the BNR addition. The addition of BNR to the expanded secondary treatment process will significantly reduce effluent nitrogen and phosphorus loads to the Red River and Lake Winnipeg. The BNR and the secondary treatment expansion projects are expected to be completed in 2012. The cost of the project will be approximately $126* million.
The addition of the equipment for the BNR program will require changes in plant processes and operations. Highlights of the changes are:
- Ferric chloride system
A ferric chloride and alum dosing system will be used to backup biological phosphorus removal and to reduce the peak phosphorus loads to the secondary treatment plant. A 70m3 chemical dosing tank will be built to store enough product for 30 days of operation.
- Bioreactors and aeration system
There will be four new bioreactors constructed at the SEWPCC. One will be located to the north and three to the south of the existing high-purity oxygen reactors. A new aeration system will be added to service the bioreactors.
- Secondary clarifier
A new secondary clarifier will be added to the SEWPCC's three existing secondary clarifiers. The design and set up of the new secondary clarifier will be the same as the existing secondary clarifiers.
- Primary sludge fermentation system
Four new circular fermenters, each 20m in diameter, will be built north of the high-purity oxygen reactors. The liquid layer above the settled layer of solids in the fermenters (supernatant) will flow to the bioreactors. Gas from each fermenter will be vented to an odour control system.
- Waste activated sludge thickeners
A new waste activated sludge thickening facility and blower system will be added at the SEWPCC. This new facility will be located within the existing sludge holding tank or truck bay building. Waste activated sludge from the surface of the bioreactors goes to the four dissolved air floatation tanks and from there flows by gravity to the sludge storage tanks.
There are three other proposed changes to the SEWPCC. Although not part of the CSIF application, these changes will be going on at the same time as the nutrient control. The details of these programs will be worked out in the design of the current upgrading of the SEWPCC. They will likely include:
- An expansion of the capacity of the SEWPCC to accommodate future growth
- An infiltration and inflow control program in the SEWPCC service area sewer system. The goal of this program is to reduce the wet weather flow to the SEWPCC which will reduce future expansion costs and improve current operations.
- Odour control (if necessary)
The SEWPCC ultraviolet disinfection system will be switched to year-round operation in the future. No major capital outlay will be required for this change. Year-round ultraviolet disinfection will reduce pathogens to the levels required by the Manitoba Environment Act licence.
The BNR process and secondary treatment expansion are linked to other components of the overall wastewater treatment program:
- SEWPCC sludge is hauled by truck to the NEWPCC where it is processed. The SEWPCC nutrient control may affect the character and quantity of biosolids produced at the NEWPCC, which may impact the City's biosolids management program.
- The combined sewer overflow control program as there are several combined sewer districts that are located in the SEWPCC service area.