AEROBIC THERMOPHILIC TREATMENT OF LANDFILL LEACHATE IN A MOVING-BED BIOFILM BIOREACTOR

In the present study the landfill leachate obtained from tabriz landfill site was first treated in a suspended growth activated sludge bioreactor which then was turned to a moving-bed biofilm bioreactor under thermophilic conditions (50ºc). the average soluble chemical oxygen demand (scod) removal ranged from 70% to 62% as organic loading rate (olr) increased from 0.454 to 4.678 kgcod/(m3.d). hydraulic retention time (hrt) values were set to 12, 14, 16.8, and 21 h. the recycle ratio of biomass ranged from 1 to 1.5. the total biomass concentration was in the range of 2600-3100 mg/l of which 60-65 percent was in the form of biofilm. it was cod removal efficiency was 5% to 10% higher in moving-bed biofilm operation compared to suspended growth one at the same olr and hrt. respirometry experiments revealed that readily biodegradable organic compounds accounted for 5.7% and 5.2% of substrate under thermophilic and mesophilic conditions, respectively. the maximum resulting oxygen uptake rates were 0.21 mgo2/(l.min) and 0.16 mgo2/(l.min) under thermophilic and mesophilic conditions, respectively.