Applications of fluidized bed reactors in wastewater treatment - A review of the major design and operational parameters

One of the current challenges of wastewater treatment is the presence of recalcitrant pollutants which are difficult to remove using conventional treatment technologies. This poses a threat to environmental sustainability and hinders the efforts of many industries to adopt cleaner production through zero discharge and subsequent wastewater reuse. Effective wastewater treatment technologies are therefore needed to address this challenge. Accordingly, the last few years have seen intensified effort to develop more effective wastewater treatment technologies. The use of fluidized bed reactor in wastewater treatment, particularly Advanced Oxidation Processes and biological treatment, represents a unique opportunity for cost-effective treatment of wastewater containing recalcitrant pollutants. Although the application of fluidized bed reactor in biological wastewater treatment is well established with many large-scale plants in existence, its application in advanced oxidation processes is mostly at laboratory-scale. For proper design, upscaling and process improvement, information on the major parameters affecting the processes is important. This paper offers an overview on the applications of fluidized bed reactor in wastewater treatment, with emphasis on the important design and operational parameters affecting its performance. The discussion covers liquid-solid and gas-liquid-solid fluidized bed reactors and their applications in advanced oxidation processes, biological as well as adsorption processes which are effective wastewater treatment technologies. Fluidized bed reactors are excellent contacting devices and have the potential to enhance the effectiveness and energy efficiency of these treatment processes if properly design and utilized. An energy efficient and cost-effective wastewater treatment technology is crucial to industries adopting cleaner production. Important parameters such as reactor geometry, aspect ratio, support materials, reactor internal, superficial fluid velocity and other operational parameters are reviewed. The review concluded with some perspectives on future research interests. (C) 2016 Elsevier Ltd. All rights reserved.