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Curtin University
Curtin Water Quality Research Centre

Characterisation of Natural Organic Matter

The high and variable levels of natural organic matter (NOM) in coloured source waters throughout Australia can contribute to major disinfection management and treatment problems (e.g. high chlorine decay rates, high concentrations of disinfection by-products, biofilm regrowth and aesthetic issues). Several treatment strategies have been investigated by water utilities, but the heterogeneity and varied dynamics of NOM in Australian source waters has challenged existing treatment processes. CWQRC has undertaken numerous projects to better characterise NOM, and is also expanding expertise developed for water studies to other fields in which NOM can prove an issue.

Current and Recent Projects

Advanced Characterisation of Natural Organic Matter (NOM) in Australian Water Supplies

Key Contacts: Cynthia Joll, Anna Heitz
Collaborators: CSIRO Land and Water, CRC WQT
Funded by: CRC WQT

This project has developed a tool-kit of advanced analytical methods facilitating the characterisation of NOM. Methodology relating to isolation procedures, derivatisation methods (e.g., thermochemolysis, chemical and enzymatic degradation) and contemporary spectroscopic methods [GC-MS, GC-irMS, NMR, multidimensional LC-MS] was developed and optimised for study of various NOM types. The spatial and temporal variability of NOM was then investigated in several selected water systems to improve our understanding of source, transport and fate of organic compounds.

Development of a Dissolved Organic Carbon Detection System for Size-Exclusion Chromatography

Key Contacts: Anna Heitz, Cynthia Joll
Collaborators: Water Corporation, AWQC
Funded by: Water Corporation

Our researchers were successful in developing a new DOC detector for size exclusion chromatography (SEC), a device that is leading to substantial advances in our studies of natural organic matter in water. Only three research groups worldwide have instrumentation with this capability, and our patentable detector has been designed to make significant improvements on the existing detectors.

The Impact of Wet Oxidation on the Organic Chemical Composition of Bayer Liquors

Key contacts: Anna Heitz, Cynthia Joll, Francesco Busetti
Collaborators: CSIRO
Funded by: CSIRO Light Metals Flagship

The Bayer Process is used to extract alumina from bauxite ore by digestion in a highly caustic solution under high temperatures and pressures. Under these conditions, a proportion of the organic matter in the bauxite is also solubilised into the liquor. The organic compounds have been found to cause detrimental effects on productivity (e.g. poisoning of gibbsite precipitation, decrease in liquor productivity, scaling) and product quality (e.g. purity, colour, particle size and strength). The objectives of the proposed study are to refine and modify analytical chemistry technology that has already been developed at CWQRC for the characterisation of NOM in waters for studies of Bayer liquors and to characterise organic matter in Bayer liquors before and after treatment with wet oxidation.

Characterisation of NOM in Highly Coloured Surface Waters

Key Contacts: Anna Heitz, Suzanne McDonald, Cynthia Joll
Collaborators: Water Corporation, Australian Water Quality Centre, Centre for Water Research, UWA
Funded by: CRCWQT and Water Corporation

The primary objective of the project is to better understand the origin, structure, reactivity and temporal dynamics of NOM in the six surface waters under study: Walpole River and Quinninup Dam (South West), Bolganup Dam, Quickup Dam and Denmark River (Great Southern) and Harding Dam (West Pilbara).

Characterisation and Treatability of Natural Organic Matter in Groundwaters used for Drinking Water

Key Contacts: Stacey Hamilton (PhD Student), Cynthia Joll

The objectives of this project are to conduct a detailed study of the origins, structural features and reactivity of NOM in a Perth groundwater. Characterisation studies providing a detailed understanding of the origins, structural features and reactivity of NOM in source waters will also help assess its treatability and possibly identify improvements to treatment processes for the effective removal of NOM.