Long term verification test for treatment performance of animal wastewater by upflow anaerobic sludge blanket (UASB) reactor

Abstract

In order to verify long term stability of swine wastewater treatment performance of upflow anaerobic sludge blanket (UASB) reactor, biochemical oxygen demand (BOD) removal rate and biogas production rate were measured for about ten years. Values of BOD were 1895±1117mg/L (average ±SD) for the influent and 886±634mg/L for the effluent. The removal rate of BOD fluctuated from 10 to 90%, and 53% in average. That in the summer of the final year was 64±13%. Biogas production volume per the removed BOD (Δ BOD) in summer was 0.1-0.8m³/kg Δ BOD. That of the final year was 0.2-0.7m³/kg Δ BOD. These results suggest that the performance of organic matter removal and biogas production was maintained almost at equal level throughout the ten years operation period. The diameter of granules in sludge drawn from the reactor at the end of operation was 1∼2mm. This value coincided with the representative value of granules in UASB reactor, which suggests that the methanogenic bacterial population was maintained in good condition throughout the operation period.