<scp>ANAMMOX</scp> performance, granulation, and microbial response under <scp>COD</scp> disturbance

<jats:title>Abstract</jats:title><jats:sec><jats:title>BACKGROUND</jats:title><jats:p><jats:styled-content style="fixed-case">ANAMMOX</jats:styled-content> (<jats:styled-content style="fixed-case">ANaerobic AMMonium OXidation</jats:styled-content>), a promising process for biological nitrogen removal, is usually affected by organic matter. In order to fully understand the effect of chemical oxygen demand (<jats:styled-content style="fixed-case">COD</jats:styled-content>) on the <jats:styled-content style="fixed-case">ANAMMOX</jats:styled-content> process, reactor performance, granular characteristics and microbial response were evaluated systematically under glucose stimulation.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>High removal efficiencies of ammonium and total nitrogen (> 90%) were achieved with 100 mg L<jats:sup>‐1</jats:sup> <jats:styled-content style="fixed-case">COD</jats:styled-content> concentration. <jats:styled-content style="fixed-case">ANAMMOX</jats:styled-content> contribution was reduced to only 69% as <jats:styled-content style="fixed-case">COD</jats:styled-content> concentration was increased to 300 mg L<jats:sup>‐1</jats:sup>. The granulation, <jats:styled-content style="fixed-case">EPS</jats:styled-content> contents, <jats:styled-content style="fixed-case">TB‐EPS</jats:styled-content>/<jats:styled-content style="fixed-case">LB‐EPS</jats:styled-content> and protein/carbohydrate were increased at a specific <jats:styled-content style="fixed-case">COD</jats:styled-content>, with higher <jats:styled-content style="fixed-case">COD</jats:styled-content> disrupting the biofacies structure. The results also showed that <jats:styled-content style="fixed-case">EPS</jats:styled-content> distribution and microbial structure were affected by the organic disturbance.</jats:p></jats:sec><jats:sec><jats:title>CONCLUSION</jats:title><jats:p>An appropriate <jats:styled-content style="fixed-case">COD</jats:styled-content> concentration enhanced the total nitrogen removal during <jats:styled-content style="fixed-case">ANAMMOX</jats:styled-content> process, by enabling a stable synergism between <jats:styled-content style="fixed-case">ANAMMOX</jats:styled-content> bacteria and heterotrophic denitrificans. Furthermore, a proper <jats:styled-content style="fixed-case">COD</jats:styled-content> stimulation promoted sludge granulation by influencing <jats:styled-content style="fixed-case">EPS</jats:styled-content> composition and distribution. However, excessive <jats:styled-content style="fixed-case">COD</jats:styled-content> disturbance disrupted the highly efficient biofacies structure and microbial balance, which then decreased the <jats:styled-content style="fixed-case">ANAMMOX</jats:styled-content> competitiveness. © 2013 Society of Chemical Industry</jats:p></jats:sec>