Full Description

A rapid characterization technique for natural organic matter (NOM), specifically designedto study water treatment processes, is reported. The organic carbon concentrations of fourNOM fractions, very hydrophobic acids (VHA), slightly hydrophobic acids (SHA),hydrophilic charged (CHA) and hydrophilic neutral (NEU), were determined. Thistechnique could be applied to study source water organic character and link in with theoperation of the treatment plant performance. This tool has the potential to guide treatmentoperators to control and monitor the treatment processes in the most effective way forNOM removal.A range of source water samples collected from various drinking water reservoirs inAustralia, including New South Wales (NSW), Northern Territory (NT), Queensland (QLD),South Australia (SA), Victoria (VIC) and Western Australia (WA), were analyzed by thisrapid characterization method. The dissolved organic carbon (DOC) concentrations ofthese samples ranged from 2 mg/L to 17 mg/L. The VHA fraction ranged between 17%and 82% of the DOC, SHA between 7% and 27%, CHA between 4% and 29% and NEUbetween 5% and 22%. This survey confirmed that organic matter in natural sources canhave a wide range of variation in both concentration and character.The feasibility of using this technique to study water treatment processes was alsoassessed using water from Myponga Reservoir, SA. This water is generally considered ahigh color and high DOC water source. Raw water and alum treated samples wereanalyzed using this fractionation technique. The treated water samples were collectedfrom a pilot plant operating in enhanced coagulation mode (pH controlled at 6.2) whichindicated the CHA fraction was readily removed compared with the other fractions. Anadditional jar testing experiment using a wide alum dose range (30-180 mg/L alum) tosimulate underdosing, conventional alum treatment, enhanced coagulation and extremeoverdosing was conducted. The variation of the residual DOC concentration of eachfraction was used to interpret the removal mechanism under different situations. Theresults showed the NEU fraction was hardly removed by alum treatment. The CHA fractionwas readily removed in the underdosing and extreme overdosing situations. In the alumdose range covering the conventional to enhanced coagulation, both the SHA fraction andVHA fraction were readily removed. Includes 14 references, table, figures.

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Edition: Vol. - No. Published: 11/02/2003 Number of Pages: 11 File Size: 1 file , 300 KB