Purification


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Treatment Process

The Bender Water Filtration Plant is a conventional water treatment facility that starts with an intake in Lake Michigan. Water enters our intake crib which is protected with bar screens and a mussel control system.

Water travelling through the intake passes a traveling screen upon arriving at the Klode Park Station. Gravity forces the water to fill a large shorewell that has several raw water pumps submersed in it. Lake water is pumped from this station to the Bender treatment plant which is nearly a mile away in Glendale.

Upon arriving at the Bender treatment plant, aluminum sulfate (alum) and polymer are added to promote settling of solids. This water then travels very slowly through a system of rectangular basins that provide a location for particulate matter to accumulate.

Rapid sand filters remove the remaining particulate matter and clean water is stored in a clearwell below the filters. There are intermediate pumps (sometimes referred to as transfer or low lift pumps) which force the filtered water through our fully redundant ultraviolet (UV) disinfection system which inactivates pathogens such as cryptosporidium. Before going into the UV reactors, fluoride is added to prevent tooth decay. After the UV reactors, sodium hypochlorite (a form of chlorine) is used to disinfect any remaining pathogens.

Underground piping directs the water to our clearwells (historically they have been referred to as our "reservoirs"). While in the clearwells, water continues to react with chlorine so that proper disinfection is achieved.

Water is drawn out of the clearwells with our high service pumps. Underground piping directs the water to a chemical feed vault that allows for the addition of ammonium hydroxide (also referred to as aqua ammonia) and phosphate. The ammonium hydroxide converts the chlorine to another disinfectant, chloramine, that is used by neighboring communities and can reduce disinfection by-products. Phosphate is also added at this point to reduce lead and copper leaching within pipes and plumbing fixtures in your home.

The high service pumps deliver potable water to its members through metering pits located on the grounds of the Bender facility. There are several interconnections between members that the NSWC monitors; however, the bulk of the water stays within each member’s system after initial delivery.


More Information about Water

For additional information about water quality on the internet, please visit WDNR’s website at http://dnr.wi.gov/topic/DrinkingWater or the EPA’s website at http://www.epa.gov/safewater.