Treating Our Drinking Water (original) (raw)

TREATING OUR DRINKING WATER

Bare Point Water Treatment Plant
Bare Point Water Treatment Plant on the shore of Lake Superior has undergone a major upgrade, completed spring of 2007.
At Bare Point raw water is pumped into the plant from Lake Superior through intake lines nearly 1 km offshore and 8 m below the surface. Large particles and debris are removed from the raw water as it travels through screens at the point where the water enters the treatment plant.

There are several different processes our water undergoes from the time it enters the plant to the time it is transported through the extensive distribution system of watermains to our homes and businesses.

1. Coagulation and Flocculation
   Coagulation is the process of rapidly mixing chemicals known as coagulants and coagulant aids to make the small physical particles in the water clump together (coagulation). In the new Bare Point Water TReatment Plant Poly Aluminum Chloride (PAC) is the coagulating agent used.
   Flocculation is gentle mixing to form larger groups of particles known as floc (flocculation).
2. Membrane Ultra Filtration
   The membrane filtration system consists of five trains of ultra filtration membranes. These hollow fiber ultra filtration membrances use gentle suction to filter impurities from water.
3. Disinfection
   The destruction of disease-causing organisms in the raw and treated water through the addition of the chemical chlorine, is the most important step in the water treatment process. Chlorine is added to our water at different points in the treatment process. When chlorine is added to the raw water as it enters the plant the process is known as pre-chlorination. When chlorine is added to the water after the filtration stage it is known as post-chlorination.

Once the water has passed through all these processes, it is pumped out of the clearwells into the distribution system.

Schematic of Bare Point Plant Operations

Loch Lomond Water Treatment Plant The Loch Lomond Plant is located south of the city limits on Mount McKay. The plant draws its water from Loch Lomond on Mount McKay, watershed located within the Fort William First Nation Reserve.

The water supply of Loch Lomond is softer, more coloured and higher in natural organic material than Lake Superior water.

1. Raw Water Screening:
   The water from Loch Lomond passes through several treatment processes. The water moves through the screens where impurities such as large particles and debris are filtered out.
2. Ultrafiltration:
   The new temporary ultrafiltration system, built in 1998, uses a synthetic fibre membrane technology to remove microscopic particulate, especially giardia and cryptosporidium cysts.
3. Disinfection:
   The water is then treated with chlorine to decrease microbiological activity and achieve thorough disinfection.

The temporary ultrafiltration system, built in 1998, utilizes a synthetic fibre membrane technology to remove microscopic particulate, including giardia and cryptosporidium cysts.

The water from the Loch Lomond supply is more ‘aggressive’ than the water from Lake Superior. This means that Loch Lomond water has a greater tendency to corrode pipes. Anti-Corrosion chemicals are required to stabilize the water flowing through our water distribution network.

Treated water from Loch Lomond is distributed by gravity feed through the city’s watermains in the downtown south core and as far as the Neebing McIntyre Floodway.

Schematic of Loch Lomond Plant Operations