Bioassessments of anaerobically decomposing organic refuse in laboratory lysimeters with and without leachate recycling and pH adjustment

In this paper, various microbial characteristics of degrading refuse in three lysimeters were compared to bioassess the operating conditions with and without leachate recycling and pH adjustment. Laboratory lysimeters with leachate recycling produced more gas and took less time to reach the highest methane percentage than a lysimeter without leachate recycling. Generally, lysimeters with leachate recycling showed high ATP (adenosine triphosphate) contents in the leachate. But there were no significant differences in dehydrogenase activities among the lysimeters. Leachate of all lysimeters inhibited the bioluminescence activities of the strain tested. Bioluminescence activity was more inhibited by the lysimeter with no leachate recycling (high inhibition corresponds to high toxicity of leachate). Generally, less inhibition was observed in the middle of the operation phase, which was related with the biodegradation activity.