The Persigo
Wastewater Treatment Plant cost 28 million dollars to build
and was put into service on January 16, 1984. The facility is
a conventional activated sludge plant with aerobic and anaerobic
sludge digestion. The influent flow is approximately 80% domestic
and 20% industrial wastewater.
Industrial wastewater falls under the control of the Industrial
Pretreatment program that was established in 1984. This program
requires non-domestic dischargers to use treatment techniques
and/or management practices to reduce or eliminate the discharge
of harmful pollutants to the sewer system.
The plant services a wide area in the grand valley that is defined
by the 201
boundary (you must have the autodesk viewer plugin
to view the map).
The wastewater
flows to the plant through a 54-inch line. About 5 miles from
the plant is the Ferrous Chloride feed station, a chemical that
is used to control odor generation. The wastewater enters the
plant through a parshall flume that meters the volume of wastes
to be treated. Next it goes through stepscreen units that screen
out coarse solids larger than 1/4-inch. Then it goes to the
grit chambers that remove any heavy inorganics, such as gravel,
coffee grounds, eggshells etc.
Influent
Stepscreens
Raw Sewage
Lift Pumps
The wastewater then
flows into the Raw Sewage Pump Station. The pump station has
4 lift pumps that pump 6,950 gpm each for a total available
capacity of 27,800 gpm. The wastewater is then pumped to the
Primary Clarifiers.
