Simultaneous removal of nitrogen and phosphorous from municipal wastewater using continuous-flow integrated biological reactor

A pilot-scale experiment was carried out to study the simultaneous removal of nitrogen and phosphorous from municipal wastewater by an innovative continuous-flow integrated biological reactor (CIBR) process. A three-phase separator was used in the CIBR process, which not only saved energy consumption of sludge returning, but also solved the sludge-gas separating problem. The optimal working condition was 2 h aeration, 1 h agitation, and 1 h settling, with an energy consumption of 0.23 kW h/[m.sup.3]. The average removal of chemical oxygen demand (COD), ammonia nitrogen (N[H.sup.+.sub.4]-N), total nitrogen (TN), and total phosphorus (TP) under the optimal conditions were 72.87, 75.23, 61.25, and 68.25%, respectively. The distributing rules of dissolved oxygen, pH, mixed liquid suspended solid, COD, N[H.sup.+.sub.4]-N, N[O.sup.-.sub.3]-N, TN, and TP in each phase of CIBR was studied. It was indicated that the appropriate condition was created for the simultaneous removal of nitrogen and phosphorus in the integrated reactor. The study demonstrated the feasibility of using CIBR process for simultaneous removal of nitrogen and phosphorus at the average temperature 12.2[degrees]C. DOI: 10.1061/(ASCE)0733-9372(2008)134:3(169) CE Database subject headings: Assets; Sustainable development; Wastewater management; Water quality.