North End Water Pollution Control Centre (NEWPCC) project upgrades
The NEWPCC has two stages of wastewater treatment:
- Primary treatment
- Secondary treatment
There are two major improvements planned for the NEWPCC:
- Addition of a year-round ultraviolet disinfection facility which will reduce the concentration of pathogens in the final effluent to compliance limits. The ultraviolet disinfection project will be completed in 2006 at a cost of $19 million, but is not eligible for CSIF funding.
- Addition of centrate nutrient removal to reduce effluent nitrogen and phosphorus loads to the Red River and Lake Winnipeg. Centrate is the nutrient-rich liquid produced from the de-watering of digested sludge. Centrate nutrient removal will be completed in 2007 at an approximate cost of $30.8* million.
The addition of centrate nutrient removal will require changes to plant processes and operations. Highlights of the changes are:
Nitrogen removal facility
A sequencing batch reactor system has been selected for nitrogen removal at the NEWPCC. The sequencing batch reactor system consists of two different operations:
- an initial nitrification process for ammonia removal, followed by
- a nitrification/de-nitrification process for nitrogen removal.
The proposed process and related changes in operations are as follows:
- Sequencing batch reactors
Two sequencing batch reactors will be installed for ammonia removal (nitrification process) and for nitrogen removal (de-nitrification process). Each sequencing batch reactor will have a volume of approximately 6000 m3. New aeration will be installed to supply air to the sequencing batch reactor system. A 1600 m3 equalization tank will be constructed to equalize treated centrate from the sequencing batch reactors before it is returned to the interceptor sewers just upstream of the plant. Off-gas from the equalization tank will be vented to the atmosphere through the exhausting ducts above the tanks.
- Addition of chemicals
Soda ash (sodium carbonate) will be added to the nitrification process for control of pH. Methanol will be added to the nitrification/de-nitrification process to provide the added source of carbon required for de-nitrification. Soda ash will be stored in a new 150 m3 tank and mixed in another 12 m3 tank. The methanol will be held in a 150 m3 storage tank. Using methanol in the process will produce carbon dioxide, a greenhouse gas. Approximately 10.9 tonnes of methanol will be used each day, which will produce approximately 15000 kg of carbon dioxide per day.
- Bioaugmentation process
Bioaugmentation is a process that introduces nitrifying bacteria from the side-stream centrate treatment to the mainstream plant. The goal of this process is to enhance nitrification in the main plant. This requires a change in process to assist the bioaugmentation process by reducing the temperature of the centrate stream to make it closer to the temperature of the mainstream in the plant.
Phosphorus removal facility
Ferric chloride will be added to the centrate stream to reduce phosphorus levels. The proposed design for the ferric chloride chemical dosing system includes the following features:
- Railcar shelter
A new building will be constructed to provide shelter for railcars delivering ferric chloride during unloading. This shelter will be ventilated while chemicals are unloaded. A strainer will be installed to prevent debris from the railcar from being transferred to the storage facility. A spill containment system will also be installed at the railcar unloading facility.
- Chemical storage tank
A new chemical storage tank will be constructed. This tank will provide operational flexibility because it can be used for many different types of chemicals. A ventilation system will be added to prevent off-gas problems. Corrosion-resistant material will be placed on the roof in the area of the vents to prevent corrosion of the roof material from condensed acidic fumes. An annex will be built next to the existing de-watering building to house the chemical storage tanks.
Nutrient control using biological nutrient removal is included in the future plans for the NEWPCC but not included in the CSIF application. It will be considered though in assessing the impacts of the CSIF project components to the river, as it is tightly linked to nutrient control at the other three water pollution control centres, as well as to the centrate treatment at the NEWPCC. All are part of the City's nutrient control program for the wastewater treatment plants.
There are a number of linkages between the NEWPCC and the other water pollution control centres because it receives biosolids from both the SEWPCC and the WEWPCC. It is also closely linked to the combined sewer overflow control program with most of the combined sewers located in its service area. All biosolids are treated at the NEWPCC which means the biosolids program is closely linked to biological nutrient removal and other aspects of wastewater management processes at the NEWPCC.