Operation of a Dual Stage Continuous Upflow Media Filter under Dynamic Conditions to Achieve Ultra-Low Phosphorus Limits

摘要

Increasingly stringent effluent phosphorus limits are driving plants to achieve ultra-lowphosphorus concentrations. The City of Coeur d’Alene (Idaho) commenced a low phosphoruspilot program to test the ability of three different technologies to achieve low effluent totalphosphorus concentrations when operated under variable conditions. The Spokane Riverdissolved oxygen total maximum daily load was finalized after the pilot program wascommenced. The final TMDL included a phosphorus wasteload allocation for the City of Coeurd’Alene equivalent to 0.036 mg/L, which became one goal of the pilot. One of the technologiesis a dual-stage continuous upflow media filter. Based on one year of operation, the dual stagefilter is capable of achieving effluent total phosphorus concentrations less than 0.036 mg/L, butis susceptible to operations and equipment issues that can increase the monthly average abovethe goal.