Nitrogen Removal from Wastewater by Coupling Anammox and Methane-Dependent Denitrification in a Membrane Biofilm Reactor

Abstract

This work demonstrates, for the first time, the feasibility of nitrogen removal by using the synergy of anammox and denitrifying anaerobic methane oxidation (DAMO) microorganisms in a membrane biofilm reactor (MBfR). The reactor was fed with synthetic wastewater containing nitrate and ammonium. Methane was delivered from the interior of hollow fibres in the MBfR to the biofilm that grew on the fiber's outer wall. After 24 months of operation, the system achieved a nitrate and an ammonium removal rate of about 190 mgN L(-1) d(-1) (or 86 mgN m(-2) d(-1), with m(2) referring to biofilm surface area) and 60 mgN L(-1) d(-1) (27 mgN m(-2) d(-1)), respectively. No nitrite accumulation was observed. Fluorescence in situ hybridization (FISH) analysis indicated that DAMO bacteria (20-30%), DAMO archaea (20-30%) and anammox bacteria (20-30%) jointly dominated the microbial community. Based on the known metabolism of these microorganisms, mass balance, and isotope studies, we hypothesize that DAMO archaea converted nitrate, both externally fed and produced by anammox, to nitrite, with methane as the electron donor. Anammox and DAMO bacteria jointly removed the nitrite produced, with ammonium and methane as the electron donor, respectively. The process could potentially be used for anaerobic nitrogen removal from wastewater streams containing ammonium and nitrate/nitrite.

The short- and long-term effects of environmental conditions on anaerobic methane oxidation coupled to nitrite reduction

“…The results of the long-term experiments also showed that the n-damo bacteria performed better at 35 C than at 30 C. Hitherto n-damo culture was most enriched at 22e30 C Raghoebarsing et al, 2006;Shi et al, 2013), but 35 C might be a better temperature of n-damo bacterial incubation according to this work. Although n-damo bacteria are still active at 45 C with a specific activity of 0.54 ± 0.05 mmol NO À 2 h À1 g À1 VSS, Hu et al (2009) failed to obtain n-damo biomass at 45 C, probably because one or more essential cell components, such as a key enzyme, became so damaged at a high temperature of 45 C that the cells lost the ability of growth (Madigan et al, 2010).…”

“…A previous work of pH effect on n-damo enrichment culture had been carried out by Zhu et al (2012), but they only investigated a narrow pH range of 5.9e7.4 in which the n-damo activity increased continuously and optimum pH value wasn't obtained, while this work supplied complete information (pH 6.0e9.0) including the part of activity decrease at high pH values. Previous n-damo cultures were most incubated in a pH range of 6.8e7.6 (Ettwig et al, 2009;Luesken et al, 2011;Shi et al, 2013), and the results of this work suggested pH around 7.6 was better than 7.0. In addition, the different pH (7.0 and 7.6) didn't change the percentage of n-damo activity (Table 1) and the abundance of 16S rRNA genes (Table 2), probably because of the similar effect of pH on n-damo and heterotrophic denitrification.…”

“…Recently, it was demonstrated that archaea from ANME-2d population is responsible for AOM coupled to NAR, which anaerobically oxidizes methane through reverse methanogenesis using nitrate as the terminal electron acceptor (Eq. (2)) (Haroon et al, 2013;Shi et al, 2013). M. oxyfera-like bacteria have been detected in some natural habitats and contribute largely to the removal of methane (the second most important greenhouse gas) (DeutzmannSchink, 2011;Hu et al, 2014b;Shen et al, 2014a).…”

Depth-specific distribution and importance of nitrite-dependent anaerobic ammonium and methane-oxidising bacteria in an urban wetland

“…Both the anammox bacteria and n-damo bacteria use the same electron acceptor (nitrite), thus they can potentially compete for nitrite in nature. So far, the co-existence of anammox bacteria and n-damo bacteria has been reported in several enrichment cultures (Luesken et al, 2011a;Haroon et al, 2013;Shi et al, 2013;Ding et al, 2014). It was observed that if ammonium was supplied in excess, n-damo bacteria were outcompeted from the enrichment culture, suggesting that anammox bacteria have a higher affinity for nitrite (Luesken et al, 2011a).…”

Advanced nitrogen removal from landfill leachate via Anammox system based on Sequencing Biofilm Batch Reactor (SBBR): Effective protection of biofilm

“…Compared with the conventional nitrification/denitrification process, Anammox does not need external carbon sources, and the power consumption for Anammox can be reduced substantially (Shi, et al, 2013). Therefore, it can effectively treat mature landfill leachate (Anfruns, et al, 2013).…”