Performance and kinetic evaluation of semi-continuously fed anaerobic digesters treating food waste: Role of trace elements

This study investigated the effects of trace elements (TEs) on the anaerobic digestion (AD) of food waste (FW) in laboratory-scale semi-continuously fed anaerobic digesters. The duration of digesters operation was approximately 400 days. Organic loading rates (OLRs) ranged from 1.0 to 5.5 g VS L-1 d(-1) at 37 degrees C. Results showed that methane production of the digester was severely inhibited at a volatile fatty acid (VFA) concentration of 30,000 mg L-1 at OLR of 4.0 g VS L-1 d(-1) in the absence of TEs. Contrary to the failed digesters, a stable performance was achieved in the TEs added digesters. High methane yield (approximately 465.4 mL CH4 g(-1) VSadded) was obtained, and no significant accumulation of VFA was observed in the TEs added digesters at OLR of 1.0-5.0 g VS L-1 d(-1) and HRT of 40 days. These findings strongly indicated that the addition of TEs has an important impact on the operation stability of AD of FW. (C) 2014 Elsevier Ltd. All rights reserved.