Wastewater Treatment Plant

Plant Capacity	846,000 Gallons Per Day
Construction Cost Of Present Additions	$1,899,000
Design Effluent Quality	BOD5     MG/L     30
Consulting Engineers	Short-Elliott-Hendrickson, Inc St. Paul, Minnesota Chippewa Falls, Wisconsin
General Contractor	Lysne Construction Inc
Mechanical Contractor	Hurlburt Heating & Plumbing Inc
Electrical Contractor	C.R.Stocks Electric Company

Sewage flows into the pumping station located approximately 1700' east of the plant and then is pumped to the treatment plant.

At the plant the sewage first enters the Grit Chamber where sand and grit is allowed to settle. The sewage is also sampled before entering  the Grit Chamber.

The sewage then flows to the Primary Clarifiers where some of the  suspended solids settle out.

Next, the sewage enters the Rotating Biological Reactors which are shafts on which a large number of 12 foot diameter plastic sheets are placed. These shafts rotate in tanks through which the sewage flows. A growth develops on the plastic sheets and the micro-organisms in this growth feed on the organics in the sewage.

The sewage now flows to the Final Clarifiers where most of the remaining suspended solids settle out. The sewage is now quite clear but still contains bacteria. This is again sampled. 

On the way to the Chlorine Contact Tank, chlorine gas in a water solution is added to the sewage to kill nearly all harmful bacteria.

The sewage, at this point called effluent, is metered and then leaves the plant and enters the Chippewa River.

The suspended solids (now called sludge) that settled out in the Primary and Final Clarifiers are pumped to the Primary Digester. In this tank the sludge is heated and mixed in the absence of oxygen and bacteria reduces the sludge volume and removes most of the odor causing elements. A byproduct of the bacteria action is methane gas which is used to fuel the  boiler that heats the sludge.

The sludge is next pumped to the Secondary Digester where it is allowed to settle. The liquid (called supernatant) is returned to the Primary Clarifiers and the solids are pumped to the Sludge Holding Tank for ultimate disposal on land.

The Control Building houses the laboratory where tests are run on the sewage.