Hydraulic investigations into decanting from IEA wastewater treatment plants. Part 2: further investigations. April 1989. Witheridge, G. M. en_US Wilkinson, D. L. en_US 2021-11-25T12:39:58Z 2021-11-25T12:39:58Z 1989 en_US
dc.description.abstract Describes an investigation into the mechanisms responsible for sludge carry-over during decant from intermittent aeration tanks. Several mechanisms were identified which may cause sludge carry-over. An "early failure" mode may occur during the transient phase at the start of decant. This can be avoided by gradually increasing the rate of decant to a final steady value. The time required for flow establishment is in the order of five minutes in tanks of current size. Following the transient phase, failure can occur when interfacial shear stresses between the supernatant and settled sludge exceed some critical value. This is considered to be a "scour failure" analagous to the onset of erosion of a cohesive sediment. Experiments conducted in a variety of different types of extended aeration tanks indicated that the critical parameters governing failure are the upstream velocity of the supernatant, the settlement time, and the Stirred Sludge Volume Index, SSVI. Appreciation of the failure mechanisms has indicated certain design improvements which could be made to existing aeration tanks, in particular to the rate of changee of weir loading and the design of scum barriers. The significance of tank depth is also discussed. en_US
dc.description.sponsorship Public Works Department, N.S.W. en_US
dc.identifier.isbn 0858243717 en_US
dc.language English
dc.language.iso EN en_US
dc.publisher University of New South Wales - Water Research Laboratory en_US
dc.rights CC BY-NC-ND 3.0 en_US
dc.rights.uri en_US
dc.source Legacy MARC en_US
dc.source WRL Digitisation
dc.subject.other selective withdrawal en_US
dc.subject.other wastewater treatment en_US
dc.subject.other wastewater facilities en_US
dc.subject.other activated sludge process en_US
dc.subject.other Hastings Municipal Council en_US
dc.subject.other Wingecarribee Shire en_US
dc.subject.other Shoalhaven City en_US
dc.title Hydraulic investigations into decanting from IEA wastewater treatment plants. Part 2: further investigations. April 1989. en_US
dc.type Report en
dcterms.accessRights open access
dspace.entity.type Publication en_US
unsw.description.notePublic Supplementary notes: See also Research report 172. en_US
unsw.identifier.doi en_US Sydney en_US
unsw.relation.faculty Engineering
unsw.relation.ispartofreportnumber UNSW Water Research Laboratory Report No. 175 en_US
unsw.relation.originalPublicationAffiliation Witheridge, G. M., Water Research Laboratory, Faculty of Engineering, UNSW en_US
unsw.relation.originalPublicationAffiliation Wilkinson, D. L., Water Research Laboratory, Faculty of Engineering, UNSW en_US School of Civil and Environmental Engineering *
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