Article ID Journal Published Year Pages File Type
4485446 Water Research 2007 12 Pages PDF
Abstract

The aim of this work was to characterise the solids in an anaerobic sewage treatment process. Hindered settling velocity, particle size distributions (PSD), influent and effluent CODP/SS and discrete settling velocity distributions were all measured.The anaerobic migrating bed reactor (AMBR) solids were mainly flocculent and had a settling rate equivalent to a good settling activated sludge (∼SSVI=60 mL/g). The PSD of the anaerobic solids were very different to PSD for activated sludge flocs, with the anaerobic solids having a modal size an order of magnitude smaller than activated sludge, but a range of particle sizes being two orders of magnitude larger. There was a far greater range in size and structure in the anaerobic solids. The anaerobic process solids were primarily feed solids undergoing VSS destruction (hydrolysis). The biological mass was small. The solids seemed to retain their size as the volatiles were degraded and the density decreased (‘skeletons’ of the influent particulates). The small fraction of slowly settling solids, which have been identified to have a similar modal size but lower density than the mixed solids in the reactor, pose a solids retention time (SRT) control problem when relying on settling alone for solids retention.

Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Earth-Surface Processes
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