Production and Removal of Soluble Organic Nitrogen by Nitrifying Biofilm

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Journal of Environmental Chemical Engineering



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This study investigated soluble organic nitrogen (sON) activity in batch reactors mimicking nitrifying moving bed biofilm reactors (MBBRs). This work was divided into two objectives focusing on the production and degradation of sON, respectively. For the first objective, a synthetic feed that did not contribute any organic nitrogen was used and results indicated that irrespective of the presence of influent organic carbon (0 versus 400 mg COD/L) in the reactors, sON was contributed by the biofilm during nitrification. Although net production of sON was observed, both production and ammonification coexisted which regulated the sON concentration. For the second objective, actual wastewater was fed to the reactors to investigate sON degradation under different carbon to nitrogen (C/N) ratios. A higher concentration of sON was biodegraded in the reactor when fed with influent containing a lower C/N ratio. Overall results suggested that organic carbon bioavailability and/or ammonia concentration influenced the production and ammonification of sON. This study is the first to explore the sON activity by MBBR biofilm and findings from this work could extend the knowledge on the fixed film process with respect to sON activity to regulate and optimize reactor operation in meeting stringent total nitrogen discharge limits.


Abbreviations AbsON bioavailable soluble organic nitrogen; ASP activated sludge process; ATP adenosine triphosphate; BNR biological nutrient removal; BOD biochemical oxygen demand; bsON biodegradable soluble organic nitrogen; C/N carbon to nitrogen ratio; COD chemical oxygen demand; DNF post-denitrification filters; DO dissolved oxygen; HPO-ASP high purity oxygen ASP; MBBR moving bed biofilm reactors; mg/L milligram per liter; MWWTP Moorhead wastewater treatment plant; RLU relative light units; sCOD soluble COD; sON soluble organic nitrogen; SWW synthetic wastewater; TN total nitrogen; TSN total soluble nitrogen; TSS total suspended solids; VSS volatile suspended solids; WRRF water resource recovery facility


Chemical Engineering | Environmental Engineering



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