Use of polypropylene biological carriers to enhance the performance of activated sludge aeration tank

Abstract

This research aims to study the possibility of raising the efficiency of the biological treatment system in the wastewater treatment plant in Hama, which operates by conventional activated sludge, using biological carriers with attached growth that is, working with a hybrid system that combines the processes of attached and suspended growth. The designed experimental unit consists of a biological basin containing: activated sludge (suspended growth), and fixed biological carriers, (attached growth), which are of polypropylene bags, and sprayer system above.  The aim of which is to distribute water homogeneously on the biological carriers, in addition to increasing the concentration of oxygen Dissolved in water, the biological basin follows a secondary sedimentation basin. The experimental unit operated in two stages: the first stage operated in the sewage treatment plant in Hama, where the average efficiency of BOD₅ removing was 74% and of COD was 78%. In the second stage, the experimental unit transferred to the Postgraduate Students Research Center at Tishreen University of the Higher Institute for Environmental Research, to provide more stable operating conditions. Two separate experiments conducted with the aim of knowing the efficiency of biological carriers: In the first experiment, the experimental unit operated without biological carriers, where the average efficiency of BOD5, COD, nitrate, and phosphate removing was: 84%, 38.5%, 22.5%, and 30%, respectively. In the second experiment, it operated with biological carriers, where the average efficiency of BOD5, COD, nitrate, and phosphate removing: 92%, 45%, 28%, and 31%, respectively. The results showed that this treatment system is stable and low in cost, and can used with high efficiency if appropriate and stable conditions were provided.