COD removal from semi-aerobic landfill leachate

Abstract

Leachate are heavily polluted liquid which may contain large amount of chemical oxygen demand (COD), biological chemical demand (BOD), ammonia (NH3) and colour. This study was conducted to examine the percentage of COD removal using coagulation as pretreatment, followed by the effects of ZnO, pH, stirring time and solar photocatalytic as final treatment. The duration of photocatalytic reaction occurs after 30 minutes of exposure to sunlight at solar intensity of 0.13 - 0.89 kW/m2 that is from 11-1 p.m. The study showed that, pretreatment of leachate by coagulation at no pH adjustment, at its natural pH 8.68 with addition 10 g/L FeCl3 as coagulant can remove 55.8% COD. But, 34% COD removal can be obtained by coagulation at pH 5 with addition 1 g/L FeCl3. Using 1.0 g/L ZnO at pH 5 capable of removing 61 % COD after 120 minutes of exposure.