Use of Layered Geotextiles to Provide a Substrate for Biomass Development in Treatment of Septic Tank Effluent Prior to Ground Infiltration

Abstract

The use of layered geotextile filters for biological treatment of septic tank effluent prior to ground infiltration was investigated. The goal was to provide secondary treatment and prevent soil clogging by fostering biomass growth in the internal porosity of commercially available geotextiles. The study used primary effluent from a water pollution control facility that serves a combined sewer area. To identify sustainable operating conditions, the hydraulic loading rate (HLR) and other parameters were varied in tests with columns packed with multiple geotextile and granular layers. At continuous high hydraulic loading rate application, over 90% of total suspended solids and biochemical oxygen demand was removed, but the three layer filters eventually clogged. When a