Digester #7 Cleaning
Digester #7 is an 80 foot diameter circular tank with a fixed concrete cover located at the Nine Springs Wastewater Treatment Plant in Madison, Wisconsin. The digester has a conical bottom with a 16.7% slope and a sidewall depth of 30 feet. Cleanout included removal of approximately 215,000 gallons of residual sludge, scum, grit, struvite and solid material from the inside of the digester.