Biocatalysis conversion of methanol to methane in an upflow anaerobic sludge blanket (UASB) reactor: Long-term performance and inherent deficiencies

Assessment of active methanogenic archaea in a methanol-fed upflow anaerobic sludge blanket reactor

“…COD removal efficiency by the end of Phase 3 (97±1%) was in the range of the 86-98%, obtained with a similar OLR as the one previously described by Badshah et al (2012). These values are also comparable or even higher than those described in previous studies with higher OLR, such as 97.1% and 92.5% with an OLR of 30 and 48 kg DQO m -3 d -1 , respectively (Kobayashi et al 2011;Lu et al 2015); showing high adaptation of the UASB biomass to the methanol feeding.…”

“…Other studies have reported the loss of acetic activity after long periods of methanol feeding (Paulo et al 2003). A recent study stated that after operating an UASB with methanol for 143 days, the granules presented an acetate SMA of 150 mg COD CH4 g -1 VSS d -1 , losing completely this capacity after 300 days of operation (Lu et al 2015). In this same study, higher SMA values were achieved for H 2 and methanol (0.08 and 2.11 g COD CH4 g -1 VSS d -1 , respectively) than those obtained in the present study.…”

Continuous micro-current stimulation to upgrade methanolic wastewater biodegradation and biomethane recovery in an upflow anaerobic sludge blanket (UASB) reactor

“…As predicated by International Energy Agency (IEA) (IEA, 2016), the uptake of renewable energy will reach 60% of the total power generated by 2040. In order to recover as much renewable energy as possible from waste sources, numerous efforts have been dedicated to the development of various energy-efficient anaerobic treatment technologies, such as upflow anaerobic sludge blanket (UASB) (Li et al, 2011;Lu et al, 2015), anaerobic submerged membrane bioreactor (AnSMBR) (Gouveia et al, 2015), etc. Of them, upflow anaerobic sludge blanket (UASB), as a well-established process, has been universally applied in various real wastewater treatment for several decades, which cannot only covert chemical energy in soluble organics present in wastewaters to value-added bioenergy but synchronously realize wastewater purification.…”

“…One of the available renewable energy reservoirs can be methanolic wastewater, an evaporator condensate with substantial energy and resource potential from the Kraft pulping process (Bhatti et al, 1996). The scientific research upon methanolic wastewater treatment by means of UASB has been initiated since late 1970s (Lettinga et al, 1979), however, until recently the potential of this approach to treat methanolic wastewater remains not clearly recognized and the long-term process stability still could not be guaranteed (Kobayashi et al, 2011;Lu et al, 2015).…”

“…In fact, this is the mostly observed scenario in methanolic wastewater treatment especially when methanol is the major carbon source. However, such system always accompanies with severe granules rupture because of excessively simple microbial community, which can induce granules washout and cause process upset and instability (Lu et al, 2015). On the other hand, the co-existence of the second rout can diversify microbial community and relieve this problem to a certain degree; however, the main issue for this scenario is acetate accumulation as a result of slow growth rate of acetoclastic methanogens as well as their high susceptibility to environment.…”