Linked Life Data

19803331

Source:http://linkedlifedata.com/resource/pubmed/id/19803331

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2009-10-6
pubmed:abstractText
The removal of natural organic matter under variable coagulation and flocculation pretreatment conditions was evaluated for three surface waters in an immersed ultrafiltration (UF) process. Coagulation with alum, flocculation and UF treatment were conducted in a bench-scale test apparatus designed to simulate pilot- and full-scale water treatment systems. Variable coagulation and flocculation operating conditions were investigated, including coagulant dose, hydraulic retention time (HRT) and mixing intensity (e.g. velocity gradient). Treatment performance was evaluated by measuring specific water quality parameters in the permeate stream, including dissolved organic carbon (DOC), UV254 and true colour. Coagulant dose was found to be the most important variable for treatment performance with regard to permeate water quality, with significantly lower alum dosages required to achieve enhanced coagulation water quality targets than conventional filtration systems. Experiments conducted to evaluate variable flocculation stage HRT and applied velocity gradient demonstrated that traditional set points for these operating variables, applied in conventional filtration systems, may not be required in UF systems. In particular, optimized UF permeate water quality was found with reduced flocculation retention times (e.g. <10 minutes) and mixing intensities (e.g. < 100 s(-1)). The impact of intermittent air scour, or air sparging, operations in the UF process tank during operation was also evaluated. The use of air scour, tested as an intermittent operation at an applied velocity gradient of 50 s(-1) was found to significantly reduce DOC concentrations and UV254 measurements in the UF permeate stream when compared with UF operations without air scour.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0959-3330
pubmed:author
pubmed:issnType
Print
pubmed:volume
30
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
927-38
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Effect of coagulation and flocculation conditions on water quality in an immersed ultrafiltration process.
pubmed:affiliation
Department of Civil and Resource Engineering, Dalhousie University, Halifax, Nova Scotia, Canada. mwalsh2@dal.ca
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't