Kingston
Central Water Treatment Plant
The Central Water Treatment Plant serves the City Central and City East areas. Annual
water-quality reports for the Central plant can be downloaded using the links at right.
Below is a description of the plant and its treatment processes.
The source of water treated by this plant is Lake Ontario at the mouth of the St. Lawrence
River. Our intake is located 1km directly south of the treatment plant, 4m off the lake
bottom, at a depth of approximately 18m. A great deal of testing was carried out in
choosing the location for the intake. This has ensured that the treatment process begins
by using the best and most consistent quality source water available, and reduces it's
susceptibility to contamination. Known sources of potential problems are few, and
contingency plans are in place in the event of raw water contamination.
When the water temperature rises above 10 degrees Celsius (above this temperature zebra mussels are
active), prechlorination takes place at the mouth of the intake. This protects the intake
from becoming encrusted with zebra mussels, which would restrict the flow of water through
the intake.
The purpose of chlorination is to provide disinfection. 12 percent Sodium Hypochlorite is
applied to the raw water in solution form.
A revolving screen in the suction well of the low lift building removes any large debris
such as weeds, fish, etc.
These pumps lift the water from lake level to the main plant. There are two pipes from the
low lift building directing the water to the mixing chambers.
Aluminum Sulphate (alum) is added to the water as it leaves the low lift building.
Particles in the water are attracted to the alum.
Water flows rapidly in these tanks in a spiral motion, allowing proper mixing of the
chlorine and alum with the water. The particles in the water will collide with the alum
particles, and then join together to form larger particles called floc.
These are large tanks designed to reduce the velocity of water allowing the heavier floc
particles to settle out. They also provide detention time, allowing the chlorine time to
achieve disinfection.
Six 'rapid sand' filters with Granular Activated Carbon (GAC) and anthracite remove the
particles that did not settle out in the settling tanks, as well as compounds that may
cause tastes and odours. Water flows through the filters to a clean water reservoir called
the clear well.
Filters are washed daily to remove the particulates they have collected over the previous
24 hrs. Clean water from the clear well is pumped backwards through the filter, and the
top layer of the filter is agitated to break up any large particles. Effluent water from
the backwash process is directed to a process waste facility for further treatment.
Effluent from the filter backwash process and sludge from the settling process are
directed to the process waste facility for further treatment. Effluent is directed to two
equalization tanks at the head of the process. Magnafloc 120L is added to the water as it
is pumped from the equalization tanks through plate settlers at which time the supernatant
from the process is de-chlorinated using Sodium Bi-Sulphite 38% solution and directed back
to Lake Ontario. The sludge produced during the process is then pumped to the sanitary
sewer system for further treatment at the Water Pollution Control Plant.
Sodium hypochlorite is added to the water as it enters the clear well to create a 'chlorine
residual' which remains throughout the distribution system. This ensures protection to the
point of the customers' tap.
Filtered water is stored here before being pumped to the distribution system or used for
filter washing.
Five high lift pumps move treated water from the clear well into the distribution system.
Diesel driven pumps are maintained to provide a continuous supply of water during power
failures. These provide enough capacity to meet fire-fighting requirements as well as
normal flows during power outages. A diesel generator provides electricity to run metering
equipment and lighting in the water plant. Standby equipment is maintained for all
critical processes.
This reservoir has a capacity of 22,700 m3. It also contains two electric pumps,
and one diesel pump. Water is pumped into this reservoir during the night and out of it
during the day.
This station is supplied by a water main running from the city central, under the
Cataraqui River, to James St. in Barriefield village. Three electric pumps are available
to pump water into the distribution system east of the Cataraqui River, including Canadian
Forces Base (CFB) Kingston. Hydrofluorosilicic acid is added to the water to create a 'fluoride
residual' for CFB Kingston, as a requirement of the Department of National Defense, to
help prevent tooth decay. As well, sodium hypochlorite is added to ensure adequate
chlorine residuals in this part of the system. The city east system has three elevated
tanks for storage, and two control valves to regulate flows to and from the towers.
Built in 1955 this steel tank is used for storage, to provide system pressure, and to act
as a buffer to pressure fluctuations.
Approximately 80,000 people are supplied with water from the Kingston Central Water
Treatment Plant. There are approximately 250 km of water mains, and over 1200 fire
hydrants in the system. Average daily flows are approximately 50,000 m3/day,
with summer time peaks of up to 72,000 m3/day.
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