Characeae and Hydrilla verticillata for Enhancing Biogas Production in Landfill Leachate

This study investigated the enhancement of biogas production in leachate wastewater under anaerobic digestion process. Characeae and Hydrilla verticillata were collected from a natural water resource, then shredded at a ratio of 1:1 (w/v) and used as a co-substrate. The simulated reactors were stabilised within 60 days of incubation. Five ratios of leachate to  co-substrate as 10:1, 10:2, 10:3, 10:4 and 10:5 were separately tested. It found that the pH ranged from 5.83 to 7.78 and 5.63 to 7.35 in Hydrilla and Characeae, respectively. The COD degradation efficiency was a range of 65 – 81% and 55 – 68% in Hydrilla and Characeae, but leachate seems to be retarded. The accumulative biogas production in leachate was significantly improved, while the biogas production in leachate was 2.6 mL. The highest accumulative biogas production was found 5193, 2943, 5654 and 5843 mL in sole and ratio five in Hydrilla , 100% and ratio four in Characeae. Moreover, these substrates could generate densely and sustained of H 2 and could initiate CH 4 after 20 days. This suggests an advantage of using Characeae and Hydrilla verticillata as a co-substrate to improve biogas and CH 4 production in long operating landfill leachate.