Sludge Thickening

Primary and secondary sludge thickening is beneficial to the anaerobic digestion process because it reduces biomass volume tank size and heating requirements. The BCUA utilizes four 65’ diameter gravity thickeners, and one centrifuge to thicken sludge prior to digestion. The gravity sludge thickening process consists of pumping both primary and secondary sludge into a gravity sludge thickening tank where the sludge is mixed and agitated gently by a rotating mechanism. The solids tend to settle to the bottom of the tank where they are pumped into the anaerobic digesters. The thickening tank supernatant is pumped to the headworks or primary effluent channel for treatment.