Studies indicate that straight septage introduction to activated sludge plants causes shock loading and subsequent violation of effluent permit standards.This project intends to evaluate dewatering of sludge by the use of wire cloth screening to determine if the dewatered sludge meets landfill acceptability standards. It intends also to determine if the return of the filtrate to the septic tank of origin or another septic tank impairs the function of leaching fields or if potential pathogen transfer from one tank to another creates a public health risk.This study will pilot test filtration of septage with a subsequent physical and chemical analysis of the sludge and filtrate. Existing data will be evaluated to assess the impact of filtrate on the function of the leaching field in addition to the reduction of the resting period. Various chemicals and polymers will be evaluated for effectiveness in the straining of septage. The technologies in question are (1) mobile vacuum filters and (2) mobile micro screens. This will also include an economic analysis. It is expected that this technology will improve the outflow characteristics of STP's of design flows <5 mgd by removing the shock load to septage from the headworks. Vacuum filtration at the plants should improve, and filtrate should contain lower BOD, TSS, and VSS. In addition, it is expected that this technology will have no adverse impact on the leaching characteristics of residential septic systems and will actually increase the pumping frequency due to the cost savings to the homeowner.
