Microbial chromate reduction coupled with anaerobic oxidation of methane in a membrane biofilm reactor.

It has been reported that microbial reduction of sulfate, nitrite/nitrate and iron/manganese could be coupled with anaerobic oxidation of methane (AOM), which plays a significant role in controlling methane emission from anoxic niches. However, little is known about microbial chromate (Cr(VI)) reduction coupling with AOM. In this study, a microbial consortium was enriched via switching nitrate dosing to chromate feeding as the sole electron acceptor under anaerobic condition in a membrane biofilm reactor (MBfR), in which methane was continuously provided as the electron donor through bubble-less hollow fiber membranes.

Perchlorate bio-reduction in a methane-based membrane biofilm reactor in the presence and absence of oxygen.

Perchlorate has been widely detected in various water environments and could cause serious health problems. Methane has been proposed as a promising electron donor to remove perchlorate from contaminated water, yet it is unclear whether and how microbial methane oxidation couples with perchlorate reduction, in particular under anoxic conditions. Here, the feasibility and performance of perchlorate reduction driven by methane in the presence and absence of oxygen were investigated and compared in a lab-scale methane-based membrane biofilm reactor.

Microbial Selenate Reduction Driven by a Denitrifying Anaerobic Methane Oxidation Biofilm.

Anaerobic oxidation of methane (AOM) plays a crucial role in controlling the flux of methane from anoxic environments. Sulfate-, nitrite-, nitrate-, and iron-dependent methane oxidation processes have been considered to be responsible for the AOM activities in anoxic niches. We report that nitrate-reducing AOM microorganisms, enriched in a membrane biofilm bioreactor, are able to couple selenate reduction to AOM.

Methane-supported nitrate removal from groundwater in a membrane biofilm reactor.

The discovery of denitrifying anaerobic methane oxidation (DAMO) has not only improved our understanding of global methane and nitrogen cycles, but also provided new technology options for removal of nitrate from nitrate-contaminated water. Previous studies have demonstrated DAMO organisms could remove nitrate and nitrite from wastewater under strictly anaerobically conditions. In the study, we investigate the feasibility of nitrate removal from groundwater, which contains dissolved oxygen in addition to nitrate.