Presentation on theme: "Metro Wastewater Reclamation District Digester Complex What works and what doesnt."— Presentation transcript:
Metro Wastewater Reclamation District Digester Complex What works and what doesnt.
MWRD Digester Complex Load - Design Configuration Feed/Recirculation Effluent Gas system Gas mixing Digester #4 modifications Strategy, feed, foam Construction effects Digester upsets What works and what doesn,t
Digester Feed Strategy Maintain constant flow rate Do not use SHT level as a pump control Control WAS solids / primary solids ratio Maintain continuos de-watering operations Maintain continuos even digester effluent flow
MWRD Digester Complex Foam Pumping Strategy Find a pump that will pump foam - a double diaphragm air actuated works well Pump foam to SHT and de-water Pump foam to digester #4 - use suppression equipment Pump foam back into itself
Aggressive Construction Schedule Construction caused process interruptions Holding solids back in process areas Backing up digestion process Increases load to digesters Causes overload foaming (upset foam) Backed up secondary Nocardia foam
What Works WAS/PRI solids control Digester temperature control Steady continuos digester flow Pressure relief manholes What Doesnt Too much WAS not enough Primary 1 degree F swing/24Hr more than 5 days Too many process interruptions No pressure relief