Journal article

Effect of coagulation conditions on the dewatering properties of sludges produced in drinking water treatment

David I Verrelli, David R Dixon, Peter J Scales

COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS | ELSEVIER SCIENCE BV | Published : 2009

Abstract

The coagulation and flocculation processes in conventional drinking water treatment generate aggregates which settle to form a sludge waste. This sludge can be dewatered further by thickening, centrifugation and filtration operations in order to recover water and minimise the volume of the waste stream. A range of water treatment sludges generated in the laboratory were characterised according to a phenomenological method that is valid from the dilute free-settling regime to the concentrated cake compression stages. These were compared with plant samples. Experimental results show that raw water natural organic matter (NOM), coagulant dose and coagulation pH affected both the rate and potent..

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Funding Acknowledgements

The authors wish to acknowledge United Utilities (UK) and Yorkshire Water for project sponsorship, and the Australian Research Council and The University of Melbourne for provision of a postgraduate scholarship. Melbourne Water, the CRC for Water Quality and Treatment, United Utilities Australia, and United Water are acknowledged for assistance in obtaining samples. The assistance of Dr. Shane R Usher and Dr. Ross G. de Kretser is also acknowledged.