Activated sludge process: Historical

In 1914 the activated sludge process was first demonstrated by Edward Arden and William T. Lockett at the Davyhulme Sewage Works in Manchester, UK (see Activated sludge process; Figure A34). Like others they were trying to improve the performance of the newly invented biological filter on which an organic gel capable of purifying effluent could grow. Arden and Lockett showed that a floc built up from sewage solids served the same purpose as the filter film and could be used over and over again. Air bubbling through the floc ensured that it mixed with the sewage. They called the process the activated sludge for reference purposes failing a better term and it promised startling improvements in performance cutting treatment time from days to hours. Such was the superiority of the new process over existing ones that it spread rapidly around the world by the Activated Sludge Company which after several changes in name has finally emerged as Water Engineering, a subsidiary of North West...