High-Rate Anaerobic Treatment of Alcoholic Wastewaters

Abstract

Modern high-rate anaerobic wastewater treatment processes are rapidly becoming popular for industrial wastewater treatment. However, until recently stable process conditions could not be guaranteed for alcoholic wastewaters containing higher concentrations of methanol. Although methanol can be directly converted into methane by methanogens, under specific conditions it can also be converted into acetate and butyrate by acetogens. The accumulation of volatile fatty acids can lead to reactor instability in a weakly buffered reactor. Since this process was insufficiently understood, the application of high-rate anaerobic reactors was highly questionable. This research investigated the environmental factors that are of importance in the predominance of methylotrophic methanogens over acetogens in a natural mixed culture during anaerobic wastewater treatment in upflow anaerobic sludge bed reactors. Technological and microbiological aspects were investigated. Additionally, the route by which methanol is converted into methane is also presente

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

“…Although bicarbonate was not added to the medium used in this assay -in order to avoid the acetogenic route-, it is produced when methanol is converted into methane (Equation 4). According to stoichiometry, up to one third of the methanol can potentially be consumed by acetogens from the endogenous methanogenic supplied bicarbonate (Florencio et al 1997). Indeed, the methylotrophic acetogenic eubacteria Sporomusa was active in the granular sludge with a low relative abundance (0.2%), and may be involved in the conversion of methanol to acetate.…”

Distillery spent wash: Treatment technologies and potential applications

“…The maximum loading rate for a stable operation was 15 kg COD m −3 d −1 at a retention time of 2.1 days. Florencio et al [53] investigated the environmental factors that are of importance in the predominance of methylotrophic methanogens over acetogens in a natural mixed culture during anaerobic treatment in UASB reactors. An increased growth rate of the methanogens at higher temperatures makes the thermophilic anaerobic digestion process a suitable alternative to mesophilic digestion [38].…”

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

“…Methanol is the simplest carbon source, but it sustains a complex web of biodegradation routs under anaerobic environments (Paulo et al, 2004). Methanol can be converted into methane either directly by methylotrophic methanogens or via intermediates such as acetate with the synergy of acetogens and acetoclastic methanogens (Florencio et al, 1997). The long-term process stability of the reactor is closely related to the route used for methanol metabolism.…”