Publications (2)4.86 Total impact
Article: Effect of alum treatment on the trihalomethane formation and bacterial regrowth potential of natural and synthetic waters.[show abstract] [hide abstract]
ABSTRACT: Waters from five reservoirs and "synthetic waters", prepared using terrestrially derived dissolved organic matter (DOM) extracted from vegetation and reservoir catchment soils, were studied for their treatability with alum using a jar test procedure. DOM in drinking water is a precursor for the formation of trihalomethanes (THM) following chlorine disinfection and can also be a substrate for microbial growth in the drinking water distribution system. The trihalomethane formation potential (THMFP) represents an upper concentration limit on THMs formed by chlorination, while bacterial regrowth potential (BRP) is an indicator of the bioavailability of DOM. BRP and THMFP were measured before and after alum treatment and the results were related to the source of the DOM. It was found that freshly derived terrestrial DOM in synthetic water resulted in higher THMFP and BRP than DOM in reservoir waters. For the samples investigated, conventional alum treatment did not always reduce the THM precursor levels formed in laboratory tests below the NH&MRC (1996) guideline level of 250 microg/L nor produce microbially stable waters.Water Research 11/2002; 36(19):4884-92. · 4.86 Impact Factor
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ABSTRACT: The objective of this study was to determine if the removal of NOM in reservoir waters in conventional treatment with alum is limited by the character of the NOM. A sequential jar test procedure, which included five treatment steps was employed to study the character of the NOM which could not be removed by flocculation/sedimentation. The NOM in the raw and treated waters was characterised by techniques including dissolved organic carbon (DOC), UV absorbance (UVA), high performance size exclusion chromatography (HPSEC), pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) and diffuse reflectance Fourier transform infrared spectroscopy (DRIFT). HPSEC analysis of the reservoir waters from three sources indicated that the organic fraction remaining after alum treatment was of lower molecular weight than that in the original raw waters. Pyrolysis of freeze dried material (FDM) from one raw water source (Hope Valley Reservoir) and following treatment with a high alum dose at pH 5 (coagulated and non coagulated material) gave by-products that indicated the presence of proteins, polyhydroxyaromatics and polysaccharides.Water Science and Technology.