Effect of Bio-brush medium: a coir fibre based biomass retainer on treatment efficiency of an anaerobic filter type reactor

Five Covered Activated Ditch (CAD) type test reactors set with five different specific surface areas (SSA) of Bio-brush were tested under four organic loading rates (OLR).Chemical Oxygen Demand (COD), reactor pH and suspended solids (SS) of the effluent of reactor with 200 m²/m³ were monitored.

The efficiency of treatment increased with increasing SSA of media. On the basis of its performance the combination of Bio-brush media with 200 m²/m³ SSA under 1.0 COD kg/m³/d OLR was selected as the best for CAD reactors and the average COD removal achieved was about 89%. Under this OLR, correction of pH could be avoided for an efficient treatment. Reactors with higher SSA of media were able to tolerate organic shock loads comparatively.

No special cycles were observed in removing biomass from the test reactor under any of the four OLRs. During maturation COD, pH and SS of treated effluent with 200 m²/m³ SSA were about 100 mg/l, 6.7 - 7.2 and 26 - 43 mg/l respectively which were below the maximum desirable levels stipulated by the Central Environmental Authority.

Key words: anaerobic; bio-brush; coir fibre; covered activated ditch; specific surface area; wastewater

DOI: 10.4038/jrrisl.v87i0.1810

Journal of the Rubber Research Institute of Sri Lanka, (2005) 87, 15-22