Development of Upflow Aerobic Granular Sludge Bioreactor (UAGSBR) for Treatment of High-strength Organic Wastewater
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2019-04-02
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Industrial wastewater, typically referred to as high-strength wastewater, is a major source of water pollution due to its elevated organic content. High-strength organic wastewaters are characterized by chemical oxygen demand (COD) concentrations greater than 4000 mg/L. The effluents of these industries need to undergo biological treatment to remove the organic matter. However, conventional biological treatment processes fail to stabilize high-strength wastewater to regulatory limits. Aerobic treatment processes are not economically feasible for the treatment of high-strength organic wastewater. Anaerobic processes suffer from low growth rate of the microorganisms, high sensitivity to toxic loadings, fluctuations in environmental conditions, and require post-treatment to bring the water quality within regulations. This work aimed at developing an upflow aerobic granular sludge bioreactor (UAGSBR) to provide a downstream effective treatment process in order to combine the benefit of anaerobic digestion (i.e., biogas production) with the benefit of aerobic treatment (i.e., better removal of organics). Moreover, it is hypothesized that effluent of anaerobic treatment provides a solubilized organic matter suitable for subsequent aerobic treatment because of its reduced organic strength and enhanced amounts of nitrogen and phosphorus. The combined system will overcome the limitations of both anaerobic and aerobic systems, such as long treatment duration and low stability due to rapid bacterial growth, respectively. In this project, biogranulation, formed by the self-immobilization of microorganisms, was employed as a novel technology in an upflow semi-pilot-scale bioreactor. These granules are dense microbial communities packed with different bacterial species, which can achieve rapid treatment for high volumes of wastewater in a smaller footprint when compared to conventional biomass. Mechanisms of granule formation and stability considering influential factors such as system start-up, organic loading rate, food-to-microorganisms ratio, and nutrients addition were examined. Treatment efficiency, assessed in terms of organics and nutrients (nitrogen and phosphorus) removal, was above 90%. The UAGSBR provides a compact system for high-strength organics wastewater treatment (at 20-30% spatial footprint of a conventional plant).
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Hamza, R. A. (2019). Development of Upflow Aerobic Granular Sludge Bioreactor (UAGSBR) for Treatment of High-strength Organic Wastewater (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.