Monitoring Septage Addition to Wastewater Treatment Plants. Volume II. Vacuum Filtration of Septage

摘要

The study examined the feasibility of using conventional vacuum filtration to dewater conditioned septage sludge, alone and in combination with thickened waste activated sludge. The septage was conditioned with aluminum sulfate, ferric chloride, and sulfuric acid, each used independently. Lab experiments were conducted with a filter leaf apparatus that simulates a coil spring vacuum filter. The capillary suction test, CST, was used to estimate filterability. Field studies, utilizing a full-scale vacuum filter and large quantities of septage, were conducted at the Medfield, Massachusetts wastewater treatment plant. The studies showed that vacuum filtration of a combined mixture of the thickened waste activated sludge and septage conditioned with either alum, ferric chloride, or acid is feasible. Excellent cake yields and filtrate quality were obtained. The cost of treating septage in the solids handling train at Medfield was less than the cost of adding septage to the liquid stream at the plant inlet.