Pilot-scale enrichment of anammox biofilm using secondary effluent as source water

Abstract Enough biomass of anaerobic ammonium oxidation (anammox) bacteria is essential for maintaining a stable partial nitrification/anammox (PN/A) wastewater treatment system. Present enrichment procedures are mainly labor-intensive and inconvenient up-scaling. A simplified procedure was developed anammox biofilm by using secondary effluent as source water with no supplement mineral medium unstrict control influent dissolved oxygen (DO). Anammox successfully enriched in two pilot-scale reactors (XQ-cul BT-cul) within 250 120 days, respectively. The specific activity increased rapidly during the last 2 months both achieved 2.54 g N2-N/(m2·d) XQ-cul 1.61 BT-cul. Similar microbial diversity community structure were obtained despite different being applied from plants. Anaerobic oxidizing genera abundance reached up to 37.4% 43.1% BT-cul biofilm, Candidatus Brocadia Ca. Kuenenia dominated biofilm. negligible adverse effect residual organics DO observed water. This could facilitate inoculation and/or bio-augmentation large-scale mainstream PN/A reactors.