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Water Treatment Process

Intake

Located at the northeastern edge of Lake Erie, in a region known as the Emerald Channel. It serves as a conduit, directing Lake Erie water to an onshore Screen House. Chemical treatment can begin at the Intake. Chlorine gas is routinely introduced at the Intake when the temperature of Lake Erie reaches, and exceeds, 50 degrees Fahrenheit, for zebra mussel control.

Raw Water Conduit

Lake water is transported by gravity, to the treatment process through the raw water conduit.

Screen House

Located onshore within the Colonel Ward Pumping Station Complex. The Screen House consists of 2 banks of traveling screens, which mechanically filter large debris from the raw water entering the treatment process. Occasionally a cationic polymer may be added after mechanical filtering to begin the coagulation process, when floc resistant algae enter the lake.

Chlorine Gas and Fluoride Feeds

Chlorine gas is added to the raw water conduit to kill pathogens. A fluoride solution is also added to promote dental health.

Thickener Decant Stream

Processed filter backwash water enters the raw water conduit vault through the Thickener's decant stream. This allows the processed backwash to be exposed to the entire water treatment process.

Coagulant Feed

An important part of the treatment process is the coagulant feed. This causes fine particles in water to clump together allowing the removal of viruses and parasites, that are too small to filter without agglomeration.

Low Lift Pumps

The low lift pumps serve a dual purpose. They serve to mix the chemical feed introduced to the raw water conduit, and they transport the water toward the surface to the Treated Water Conduit.

Treated Water Conduit

This conduit transports the chemically treated water through the flocculation stage.

Rapid Mix

This is a mechanical mixer within the treated water conduit that allows for additional chemical feeds to be introduced to the water treatment process prior to sedimentation.

Polymer Feed Line

This is a static feed line within the treated water conduit, that allows for an additional polymer coagulant feed to be introduced to the water treatment process prior to sedimentation.

Flocculators

Water, from the treated water conduit is directed underground to a series of large, slow-moving mechanical paddles which promote the formation of floc. The previously introduced coagulant imparts a charge to particles in the water. The slow mixing induced by the flocculators cause these particles to clump together. This helps to improve the settleabilty or filterability of debris in water.

Sedimentation Basin

Floc-laden water is introduced to a large baffled basin. The baffling serves to limit the velocity of the water and further encourage particle clumping. The heavier dense settle by gravity to the bottom of the basin, where they accumulate as sludge. The lighter clumps will float or suspend within the basin's water, destined to be removed through filtration.

Settled Water Conduit

Treated water leaves the sedimentation basin via the settled water conduit en route to the rapid sand filter banks.. This water contains floc that is too light to settle out in the sedimentation basin.

Chlorine Gas to Filters Feed

Within the settled water conduit is another chlorine gas feed. This disinfectant feed allows the plant to increase the chlorine residual of the treated water prior to entering the filter beds and clear well storage.

Coagulant to Filters Feed

When necessary a coagulant is added to the settled water conduit to increase the filterability of the treated water prior to filtration.

Rapid Sand Filters

Water is directed from the settled water conduit to the rapid sand filters, where lighter floc, created in the sedimentation basin, is removed from the treated water. The rapid sand filters use anthracite, derived from coal, as its' filter media. Filtration occurs through adsorption on the anthracite's surface area. The filtered water, now cleared of floc and debris, is directed to an underground clear well.

Clear Well

Filtered water is stored in the clear well until it is directed through the distribution system by pumps located at the Colonel Ward Pumping Station and the Massachusetts Pumping Station. As the water leaves the clear well a polyorthophosphate is added as a corrosion control. This chemical inhibits lead from contaminating the distribution water from old pipes that our customers may have.

Washwater Tanks

The rapid sand filters are backwashed with potable water stored in our Washwater tanks. Every time a filter is backwashed, approximately 100,000 gallons of potable water is used.

Backwash Process

Filters are kept clean by the backwash process. Water, stored in our Washwater Tanks, is directed through the filter from bottom to top, while a filter sweep ( a spinning sprinkler system aimed at the filter) blasts the filter with water from the surface. These action dislodge dirt and debris trapped within the filter's media, cleaning the filter.

Equalization Basin

Used backwash water and leakage are directed into a large holding vault known as the "Equalization Basin". Water from this basin is directed into our backwash station.

Backwash Station

Collected backwash and leakage water is sent from the equalization basin to a large well, known as the backwash station. Here, backwash and leakage water is directed into our Thickeners by a series of pumps, for processing.

Thickeners

As backwash and leakage water enters the Thickeners, a non-ionic polymer is added to coagulate the debris. This treated backwash water is directed to the Thickener's settling tubes, where the large surface area encourages settling. The settled backwash is known as sludge. The cleared processed liquid is known as decant water.

Thickener Decant Stream

The decant, produced from the thickener is directed over a weir (notched barrier) and is allowed to enter our raw water conduit to undergo the full water treatment process.

Thickener Solids Stream

The sludge, produced in the settling tubes by non-ionic polymer addition, is pumped into an on-site lagoon.

Lagoon

The on-site lagoon will accept and store sludge produced in our Thickeners and Sedimentation Basin. The stored sludge will further settle due to gravity and the freeze/thaw process. The lagoon's decant is pumped to the Buffalo Sewer Authority, while the sludge is processed through a belt press or centrifuge, and trucked to an Off-Site Landfill.