Effects of spiked metals on the MSW anaerobic digestion

Abstract

This study aimed to investigate the effects of eight metals on the anaerobic digestion of the organic fraction of municipal solid waste (OFMSW) in bioreactors. Anaerobic bioreactors containing 200 mL MSW mixed completely with 200 mL sludge seeding. Ca and K (0, 1000, 2000 and 6000 mg L−1) and Cr, Ni, Zn, Co, Mo and W (0, 5, 50 and 100 mg L−1) of various dose were added to anaerobic bioreactors to examine their anaerobic digestion performance. Results showed that except K and Zn, Ca (~728 to ~1461 mg L−1), Cr (~0.0022 to ~0.0212 mg L−1), Ni (~0.801 to ~5.362 mg L−1), Co (~0.148 to ~0.580 mg L−1), Mo (~0.044 to ~52.94 mg L−1) and W (~0.658 to ~40.39 mg L−1) had the potential to enhance the biogas production. On the other hand, except Mo and W, inhibitory concentrations IC50 of Ca, K, Cr, Ni, Zn and Co were found to be ~3252, ~2097, ~0.124, ~7.239, ~0.482, ~8.625 mg L−1, respectively. Eight spiked metals showed that they were adsorbed by MSW to a different extent resulting in different liquid metals levels and potential stimulation and inhibition on MSW anaerobic digestion. These results were discussed and compared to results from literature.