Evaluation of the critical factors that influence the performance of a Geo-Fabric based Bio-Filter (GFBF)

Bio-filters are high-rate aerobic biological systems with porous support media for biofilm formation and filtration of suspended solids. The support media and its ability to remove contaminants decides the performance of bio-filter. Geo-fabrics, with properties like permeability and large surface area are capable of maintaining good biomass which in turn can absorb and adsorb substrate from influent to make them an attractive media for bio-filter systems. This paper investigates the critical factors that determine the performance of a Geo-Fabric based Bio-Filter (GFBF). Experiments conducted using geo-fabric of varying GSM were analyzed and optimized using Response Surface Methodology. The results indicated that by varying process variables like HRT, C:N ratio, rate of aeration and depth of filter, the geo-fabric with 500 GSM value showed improved performance compared to geo-fabric of 300 GSM and 400 GSM. The final experimental run conducted on GFBF with geo-fabric of 500 GSM at optimized value of process variables, observed 91 %, 98 %, 88 %, 90 % and 71 % removal of COD, BOD, NH3-N, turbidity and TDS respectively. GFBF are suitable for treatment plants where the amount of wastewater generated is relatively small and a complete treatment can be accomplished in one unit.