Dissolved methane oxidation and competition for oxygen in down-flow hanging sponge reactor for post-treatment of anaerobic wastewater treatment

Abstract

Post-treatment of anaerobic wastewater was undertaken to biologically oxidize dissolved methane, with the aim of preventing methane emission. The performance of dissolved methane oxidation and competition for oxygen among methane, ammonium, organic matter, and sulfide oxidizing bacteria were investigated using a lab-scale closed-type down-flow hanging sponge (DHS) reactor. Under the oxygen abundant condition of a hydraulic retention time of 2h and volumetric air supply rate of 12.95m(3)-airm(-3)day(-1), greater than 90% oxidation of dissolved methane, ammonium, sulfide, and organic matter was achieved. With reduction in the air supply rate, ammonium oxidation first ceased, after which methane oxidation deteriorated. Sulfide oxidation was disrupted in the final step, indicating that COD and sulfide oxidation occurred prior to methane oxidation. A microbial community analysis revealed that peculiar methanotrophic communities dominating the Methylocaldum species were formed in the DHS reactor operation.

Pilot scale application of anaerobic baffled reactor for biologically enhanced primary treatment of raw municipal wastewater

“…Hartley and Lant (2006) reduced dissolved methane losses to 5e11% of the total production through forced stripping during intermittent gas mixing and methane oxidation by the addition of up to 15% oxygen by volume (using air) in the headspace (microaeration) in the last chamber of an anaerobic migrating bed reactor. Laboratory scale downflow hanging sponge reactors were demonstrated to remove up to 80% of the dissolved methane from synthetic anaerobic reactor effluent while concurrently removing COD and ammonia (Matsuura et al, 2010;Hatamoto et al, 2011). The methane could also serve as a carbon source for heterotrophic denitrification in an anoxic-aerobic secondary biological process.…”

Stripping and Dissipation Techniques for the Removal of Dissolved Gases From Anaerobic Effluents

“…The studies so far have basically focused on improving the post-treatment of the anaerobic effluents, aiming to promote the biological oxidation of dissolved methane Matsuura et al, 2010;Hatamoto et al, 2011). Flaring, incineration and energy recovery could be considered, but only if the waste gases are concentrated, for example, by membrane separation processes (Bandara et al, 2011), dissipation chamber (this article) or by mixing gas streams rich in CH 4 (eg: biogas).…”

“…In a recent study using membranes to remove dissolved gas, Luo (2014) obtained high removal efficiencies for methane, around 86%; however, it is still an expensive technique. Other researchers are focusing on improving the post-treatment of the anaerobic effluent to promote a controlled biological oxidation of dissolved CH 4 , for example, using a closed-type down-flow hanging sponge (DHS) reactor Matsuura et al, 2010;Hatamoto et al, 2011).…”

A new degassing membrane coupled upflow anaerobic sludge blanket (UASB) reactor to achieve in-situ biogas upgrading and recovery of dissolved CH 4 from the anaerobic effluent

“…CO 2 in the liquid of the UASB reactor was desorbed and recovered in the DU by vacuum. Furthermore, another important goal was to decrease the dissolved CH 4 in the anaerobic effluent and thus prevent its release to the environment [8][9][10]. In our concept, the anaerobic effluent of the UASB reactor is passed to the degassing module, which will remove the dissolved CH 4 .…”