New approach for integral treatment of OFMSW: Comparative analysis of its methane performance versus a conventional continuously stirred tank reactor

The overall objective of this study was to compare the methane performance between a new four-stage scheme to degrade OFMSW as source of substrate versus a conventional methanogenic continuously stirred tank reactor (CSTR) operated at its optimum hydraulic retention times (HRTs). The new approach proposed is based on a methanogenic up-flow anaerobic filters (UFAFs) reactor as biomethanization technology. To develop this comparative, in this study was necessary to determine experimentally the HRT in which maximum methane production was reached (optimum HRT) using UFAF technology. Bio-hydrogen effluents resulting of the dark fermentation of OFMSW coming from a full-scale mechanical-biological treatment plant was used as feedstock. To determine the optimum HRT, a sequential decreasing of this operational parameter from 7.5 to 1.5 days was established. The results obtained indicate that the maximum specific methane yield, 0.26 and 0.28 LCH4/g CODr respectively, were obtained at 3 days HRT in mesophilic (35 degrees C) and thermophilic (55 degrees C) regime of temperature. Finally, the comparative analysis showed that the methane production of the new scheme based on methanogenic-thermophilic UFAF reactor is approximately 4 times higher than methanogenic-thermophilic CSTR (2.00 versus 0.48 LCH4/L/d respectively) and, in addition, higher methane percentage on biogas is reached (75.9% versus 70.6% respectively). (C) 2013 Elsevier B.V. All rights reserved.