(503e) Biological Nutrients Removal from Municipal Wastewater Using a Novel Circulating Fluidized Bed-Bioreactor

The objective of this study was to examine the feasibility of a novel liquid-solid circulating fluidized bed bioreactor (LS-CFBBR) in municipal wastewater treatment. The CFBBR employs attached microbial films for biodegradation of both organics and nutrients, in both soluble and particulate forms, within a single circulating fluidized bed unit. This new technology combines the more compact and efficient fixed-film process with the recently developed biological nutrient removal (BNR) process that provide the additional removal of nitrogen and phosphorous. A lab-scale CFBBR has been demonstrated to be able to treat degritted municipal wastewater The CFBBR was operated at an empty bed contact time (EBCT) of 0.82 hours with and without particle recirculation. More than 80% organic removal, 70% nitrogen removal and 30% phosphorus removal were observed without particle recirculation. With particle recirculation the system was able to achieve effluent quality characterized by BOD5 <5 mg.L^-1, TSS of <5 mg.L^-1, ammonia-nitrogen <1 mg.L^-1, total nitrogen <7 mg.L^-1, phosphorus <1 mg L^-1 and UV transmissivity of 85% at an overall HRT of 2 hours. A high transmissivity of the effluent makes it ready for ultra-violet (UV) disinfection and reuse. Combination of nitrification, denitrification and biological phosphorus removal in one unit saves space, reduces energy consumption and also produces less sludge. Remarkably lower sludge yield of 0.13 g VSS.g^-1COD, approximately one-third of the conventional treatment processes, of this system is able to reduce overall cost of wastewater treatment process. To commercialize this novel technology a pilot-scale CFBBR at a capacity of 6000 L d^-1 has been established and commissioned at the Adelaide Pollution Control Plant in London, Ontario for the treatment of degritted municipal wastewater, for pre-commercialization confirmation.