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 (50?C). 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.