The Red Oak wastewater plant is a Grade III trickling filter treatment
facility. The plant is designed to treat an average dry weather flow of
1.2 million gallons / day (MGD), an average wet weather flow of 2.2 MGD,
and a maximum flow of 4.9 MGD. The design biochemical oxygen demand
(BOD) load is 1895 lbs. / day.
All waste water comes into a
pump station where it goes through a bar screen to remove debris that is
too big to go through the pumps. It is pumped to the grit removal
system and then the water is divided between 2 primary clarifiers.
Sludge settles and flows to a sludge thickener for further settling.
Scum, which is made up mostly of household grease, floats to the top and
is skimmed off and pumped to the digester.
Flow from the
primary clarifiers is pumped to the trickling filter for removal of BOD.
It then is pumped to the packed towers which aid in the removal of
ammonia nitrogen. The water then flows to the 2 final clarifiers. Any
sludge will settle and flow to the sludge thickener. The water that
overflows the final clarifiers is then discharged to the East
Nishnabotna River.