Enhanced anaerobic digestion of phenol via electrical energy input

Enhanced Anaerobic Digestion by Stimulating DIET Reaction

“…However, the produced hydrogen was easily further converted to CH 4 on the cathode, while the overall CH 4 production rate was increased. The interesting thing found here was that the amounts of CH 4 generated through the electrodes in BES-AD systems were limited, while the majority of CH 4 production was assigned to the bulk of the broth, indicating active DIET reaction happening in the bulk [3,[27][28][29].…”

“…For instance, when overall energy yield from a certain reaction is limited, the consumption of energy for generating metabolite, as electron shuttles, can be unfavored; instead, DIET in such case can be the optimal choice for energy saving [10,38]. For example, DIET could dominate over other IIET routes, when the system was subjected to acidic inhibition [45,46], toxic substrate [29,43], sulfate-rich wastewater [47], or ammonia containing wastewater [48].…”

“…But, some reports showed that an increase in CH 4 yield can be also observed after CM supplementation [43,63]. DIET-stimulated digesters were also able to sustain against the harsh operational conditions, e.g., accumulation of sulfate [47] or ammonia [48] or phenol [29]. Consequently, previous studies highlighted that complex substrates, e.g., dog food, sugar industrial wastewater, and leachate of municipal solid waste, can be effectively treated under DIET-stimulated conditions [49,[64][65][66][67].…”

“…Variation in the optimal EV was found in the literature. For instance, EV of −0.3 V vs. SHE was found to be effective for the treatment of phenol [29] and waste activated sludge (WAS) [86]; however, when EV was changed to -0.6 V vs. SHE, no change in the enhanced performance was observed in the case of phenol, while negative impact was denoted in the case of WAS. Other studies showed different results while optimizing EV.…”

“…Li et al [26] observed an increase in electron transfer rate from 0.0017 ± 0.0003 to 0.0056 ± 0.0015 s −1 , as a result of carbon cloth supplementation. Additionally, DIET could be stimulated through the establishment of two electrodes inside AD reactor, under slight EV with/without the presence of CM [3,[27][28][29]. Such systems were called as bioelectrochemical systems merged with anaerobic digestion (BES-AD), which were initially applied for hydrogen generation [30][31][32][33].…”