STEP 6 – Secondary Clarifiers

After Growing All those Microorganisms, We Settle them Out

In the aeration basins we grew microorganisms that changed the ammonia from urine into nitrogen gas. They also ate sludge out of the water. In the secondary clarifiers we let the microorganisms and bacterial colonies, settle out of the water. This water looks clean enough to drink, but it is not drinking water! After we disinfect the water, we will put it in the river.

Some of the sludge that is collected goes to digesters where microorganisms digest it and produce methane gas. This gas is used to generate electricity for the plant.The rest of the sludge is returned to the aeration basins so that the microorganisms can continue to clean the wastewater stream.