Development of Membrane Based Septic Tank in Treating Domestic Wastewater

Abstract

Centralized treatment systems are complex and expensive in terms of construction, operation, and maintenance. Whereas decentralized systems are simpler and low cost in operations at or near the point of wastewater generation. Therefore, the most suitable approach for sanitation in developing countries is decentralized on-site treatment of wastewater. Several options are available for on-site wastewater treatment. Among them, on-site anaerobic treatment such as septic tank systems is considered the best suited. The septic tank is a conventional on-site wastewater disposal system providing only primary treatment (settlement of solids) offering little biological degradation. To further improve the quality of treated water, conventional septic tank can be modified by the introduction of membrane module capable of effective rejection of suspended solids as well as associated particulate organic matter. The study reveals that a pilot-scale membrane based septic tank using flat-sheet woven fiber microfiltration membrane (WFMF) module is able to remove SS 65%, Turbidity 99%, COD 60%, coliform (99%) and even N 50%, P 45% from institutional wastewater. Effluent of the membrane septic tank can be used for horticulture, landscaping and any other non-potable purposes.