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Removal of bioavailable dissolved organic nitrogen in wastewater by membrane bioreactors as posttreatment: Implications for eutrophication control

Hu, Haidong, Ren, Hongqiang
Bioresource technology 2019 v.271 pp. 496-499
algae, bacterial biomass, dissolved organic nitrogen, eutrophication, hydrophilicity, mass spectrometry, membrane bioreactors, porosity, primary productivity, t-test, thermoplastics, wastewater
Bioavailable dissolved organic nitrogen (ABDON) is the component of dissolved organic nitrogen (DON) which supports the growth of algae. Previous research indicates that a membrane bioreactor (MBR) is effective in reducing DON, however, its ability to remove ABDON remains unknown. The present study investigated three full-scale MBRs (membrane type: hydrophilic polyvinylidene fluoride and membrane pore size: 0.04–0.1 µm) as posttreatment for the removal of ABDON. Results showed that the concentrations of ABDON were not significantly different between influent and effluent at each MBR (p = 0.067–0.614, t-test). Analysis of DON molecular composition via ultrahigh resolution mass spectrometry provides supporting evidence that bacterial biomass produced/released ABDON during the biological processes, which would be one of the possible reasons for the low removal efficiency of ABDON (<0%−14.0%) occurred in the MBR process. Overall, MBRs as posttreatments would have a smaller-than expected impact on primary productivity in receiving waters since a substantial fraction of DON stimulating algal growth cannot be removed by this treatment.