Treatment of domestic wastewater by an underground capillary seepage system

The article presents a case study on the treatment of domestic wastewater u sing underground capillary seepage system. The system, which combines sedim entation, soil infiltration and biofilm processes, was designed to treat do mestic wastewater from toilet, bathroom and restaurant. During the 3-year o peration, performance of the system was found to be excellent with the remo val rates of 92.6, 97.6, 86.8 and 81.72% for chemical oxygen demand (COD), biochemical oxygen demand (BOD5), suspended solid (SS) and NH4+-N, respecti vely. The effluent of the system was able to be used to water lawns, flush roads or rinse toilets. Our study indicated that the percentage of wastewat er that can be reused amounts to more than 70% through the system. (C) 1998 Published by Elsevier Science B.V. All rights reserved.