Application of an enrichment culture of the marine anammox bacterium "Ca. Scalindua sp. AMX11" for nitrogen removal under moderate salinity and in the presence of organic carbon. (1st March 2020)

• Record Type: Journal Article
• Authors: Ali, Muhammad; Shaw, Dario Rangel; Saikaly, Pascal E.
• Is Part Of: Water research. Volume 170(2020)
• Publication Date: 2020-03-01
• Subjects: Biological nitrogen removal -- Anammox -- Seawater toilet flushing -- Candidatus Scalindua; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2019.115345
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Seawater can be directly used for toilet flushing in coastal areas to reduce our dependence on desalination and freshwater resources. The presence of high-salt content in the generated wastewater from seawater toilet flushing could limit the performance of conventional biological nitrogen removal processes. Anaerobic ammonium oxidation (anammox) process is regarded as one of the most energy-efficient process for nitrogen removal from N-rich waste streams. In this study, we demonstrated the application of a novel marine anammox bacterium ( Candidatus Scalindua sp. AMX11) in a membrane bioreactor (MBR) to treat moderate-saline (∼1.2% salinity) and N-rich organic (2 mM acetate) solution, prepared using real seawater. The MBR showed stable performance with nitrogen removal rate of 0.3 kg–N m −3 d −1 at >90% N-removal efficiency. Furthermore, results of 15 N stable isotope experiments revealed that anammox bacteria was mainly responsible for respiratory ammonification through NO3 − reduction to NH4 + via NO2 −, and the by-products of respiratory ammonification were used as substrates by anammox bacteria. The dominant role of anammox bacteria in nitrogen removal under saline and organic conditions was further confirmed by genome-centric combined metagenomics and meta-transcriptomic approach. Taken together, these results highlight the potential application of marine anammox bacteria for treating saline wastewater generated from seawater toilet flushing practices. Graphical abstract: Image 1 Highlights: Ca. Scalindua enrichment culture applied for saline wastewater treatment. Stable NRR of 0.3 kg–N m −3 d −1 achieved at 1.2% salinity and 2 mM acetate. 15 N isotope incubations revealed that marine anammox played dominant role in DNRA. Genome-centric metatranscriptomic confirmed the findings of isotope incubations.