Treatment of septic tank effluent in a peat filter

Abstract

Column studies were conducted to evaluate the performance of a peat filter system in removing pollutants from the septic tank effluent. Breakthrough curves were obtained from the continuous operation of five columns, each with 100 mm inside diameter and different depths of peat (200, 250, 300, 350 and 500 mm). Each column was sequentially dosed at uniform rates of 64, 89, 115 and 140 mm/d of septic tank effluent for 14, 16, 10 and 4 weeks respectively. The results of column studies showed SS removal of 85 to 99%, BOD removal of 78 to 90%, COD removal of 66 to 72%, TKN removal of 0 to 90% and phosphorus removal of 0 to 25%. Excellent (greater than 95%) fecal coliform reductions were obtained. The application of the mathematical model of Thomas and the bed depth‐service time (BDST) model to the data result in a slight overestimation of the peat bed volume.