Physical (primary) Processing
• Bar Screens in grit chamber: traps large debris
• Material is dried & sent to landfill
• Primary Clarifier: settling tank. Material skimmed off top. Heavier solids settle and drawn off the bottom. Waste sent to digester
Biological (secondary) Processing
• Anaerobic Digester: closed tank with floating lid. Microbes in break down organic matter (microorganisms, plant matter, etc).
• Methane produced. Can be used in cogeneration.
• Leftovers are landfilled after being dewatered.
• Wastewater is sent to aeration tank. Aerobic digestion occurs.
• Amount of nutrients decrease, BOD decreases.
Final Treatment
• Wastewater is sent to settling tanks
• Pumped through UV or chlorine-based system to sterilize/kill bacteria.
• Treated water is sent into a waterway.