Wastewater treatment by microorganisms – activated sludge tank

BiologyBiotechnologyAges 15–16

Wastewater rich in organic matter (high BOD) flows into a tank, where aerobic bacteria feed on the organic matter using oxygen supplied by an aerator. Adjust the influent BOD, aeration level, sludge (biomass) concentration and retention time to see BOD fall, dissolved oxygen change, and when the effluent meets discharge standards; turn the aeration off to see the tank turn anaerobic, treatment slow down, and odors appear.