Reclamation and Reuse of Wastewater by Biological Aerated Filter Process

The Biological Aerated Filter process (BAF process) is ideal for reclamation and reuse of wastewater. It features excellent removal of organic matter and SS. Moreover, it features easy maintenance and achieves energy-saving and space-conservation. Results of applying this BAF process for the reclamation and reuse of domestic-type wastewater in an office building, castor oil containing industrial wastewater in an aluminium rolling mill, and industrial wastewater in a paper mill are summarized in the following. Treatment of office building domestic-type wastewater. Combining the BAF process with sand filtration and ozonation processes, in the office building's water reuse facility, achieved favorable treatment yielding an effluent with a BOD of less than 5 mg/liter and SS of less than 1 mg/liter. In the course of the investigation, however, it was found that certain types of algicides for eliminating water moss in the cooling tower had a negative effect on the BAF process, which lasted for some time but which eventually disappeared. Treatment of aluminium rollingmill industrial wastewater. Treatment of castor oil containing influent (BOD: 40 mg/liter and n-Hexane extracts: 40 mg/liter) by the BAF process yielded an effluent with a BOD level of 5 mg/liter and a value of 10 mg/liter n-Hexane extracts. Light shielding was effective for preventing the generation of slime. Treatment of paper mill industrial wastewater. Paper mill industrial wastewater was treated through a combined treatment comprising the coagulation and sedimentation process (Pellet Blanket Separator; PBS), the BAF process, and the activated carbon adsorption process. The resulting effluent had the COD down to 30 mg/liter and the SS to 5 mg/liter. Under normal circumstances, only the coagulation and sedimentation process and the BAF process were sufficient for achieving target treatment values. There was no need to carry out the activated carbon adsorption process.