Laboratory and Pilot Scale Evaluation of Coagulation, Clarification, and Filtration for Upgrading Sewage Lagoon Effluents

摘要

Lagoons are recognized as an economical method for treating the wastewaters generated at recreation areas and other small flow-producing installations. Unfortunately, in many cases the algae-laden effluent from such lagoons may be objectionable. Various treatment techniques have been utilized in an effort to upgrade lagoon effluents to a water quality level acceptable to permitting authorities. The purpose of this study is to determine the technical feasibility of developing a mobile chemical-physical treatment facility to convert complete retention lagoons to controlled discharge systems, thus increasing design capacities. A truck-mounted chemical-physical treatment facility was designed and constructed for this study. Unit processes constituting the treatment facility included: coagulation, flocculation, sedimentation, and filtration. Analyses were performed to determine treatment efficiencies for biochemical oxygen demand (BOD5), chemical oxygen demand (COD), suspended solids, and orthophosphate. The algal genera present within the lagoon system being stuided were also identified. The efficiency of several coagulants alone and in combination with coagulant aids was investigated. Optimum dosages of coagulant and/or coagulant aid were determined.