(70cl) Simultaneous Carbon, Nitrogen and Phosphorous Removal from Municipal Wasewater in a Circulating Fluidized Bed Bioreactor

In this study, the performance of the circulating fluidized bed bioreactor (CFBB) with anoxic and aerobic beds and employing lava rock as a carrier media for the simultaneous removal of carbon, nitrogen and phosphorus from municipal wastewater at an empty bed contact time (EBCT) of 2.4 hrs was discussed. The CFBB was operated without and with bioparticles' recirculation between the anoxic and aerobic bed for 260 and 110 days respectively. Without particles' recirculation, the CFBB was able to achieve carbon (C), total nitrogen (N) and phosphorous (P) removal efficiencies of 94%, 80% and 65% respectively, whereas with bioparticles' recirculation, 91%, 78% and 85% removals of C, N and P were achieved. The CFBB was operated at long sludge retention time (SRT) of 45 ? 50 days, and achieved a sludge yield of 0.12 ? 0.135 g VSS/g COD. The effect of superficial liquid velocity (v) on biomass detachment without and with bioparticles' recirculation was investigated. A dynamic stress study of the CFBB was carried out at varying feed flow rate and influent ammonia concentration to determine response to shock loadings.