We Dewater the Sludge Twice
Before Going to the Digesters
We dewater the sludge before it goes into the digesters in order to concentrate the sludge. This helps the microorganisms do their job of digesting, and we are able to fit more sludge into the digester by getting rid of excess water.
After the digesters
The sludge from the digesters is heavy with water. Before it is trucked to the Soil Amendment Facility, we add a polymer thickener and then spin it to get water out. That makes it easier to transport and easier to handle. The biosolids left after spinning are called "cakes" and the water that comes out is called the "centrate." Centrate is sent back through the cleaning process at the plant. The centrifuges that dewater the sludge from the digesters processes about 500,000 gallons of sludge every day.