STUDY ON AERATED BIOFILTER PROCESS UNDER HIGH-TEMPERATURE CONDITIONS

A biological aerated filter combines bacterial degradation of pollutants by fixed biomass with physical filtration in a single reactor at a pilot plant, was utilized for organics removal under tropical climatic conditions. Modified domestic wastewater was used as feed, in the upflow mode. The process consisted of a granular media bed of polystyrene with a specific gravity less than water. Headless during biofiltration was studied as a function of wastewater temperature, flow velocity and time. Experiments were conducted at 4 different temperatures (30, 38, 45 and 55 degrees C) with 4 velocities (2, 4, 6 and 8 m h(-1)). The lowest filter run time range was 5.5-10 hours at 38 degrees C, with over 84% of the soluble COD removal at all velocities investigated. A decreasing gradient of biomass from bottom to top of the reactor was observed. The optimal suspended solids removal occurred at 30 degrees C with 6 m h(-1) velocity indicating that at lower temperatures, maximum suspended solids removal could be obtained. The results indicated that effluent SS could be less than 30 mg L(-1) meeting the typical standard for secondary treated effluent.