HR: 0800h
AN: B11A-0059    [Abstracts]
TI: Biochemical composition of organic matter in UK Midlands catchments: implications for drinking water treatment
AU: * Bieroza, M
EM: mzb605@bham.ac.uk
AF: School of Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
AU: Bridgeman, J
EM: j.bridgeman@bham.ac.uk
AF: School of Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
AU: Baker, A
EM: a.baker.2@bham.ac.uk
AF: School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
AB: Insufficient removal of natural organic matter at treatment works can lead to the formation of potentially carcinogenic disinfection by-products (mainly trihalomethanes and haloacetic acids, THMs and HAAs) due to reactions of residual organic matter with chlorine added at the disinfection stage of water treatment process. However, the total organic carbon (TOC) removal efficiency is controlled by the content and character of organic matter in treated water, spatially and temporally dependent (e.g. the ratio of hydrophylic and hydrophobic fractions). Thus, a better understanding of organic matter composition can affect the treatment process strategies, improving the THM formation prediction and the quantification of coagulant and disinfection dosages. Fluorescence analysis of organic matter composition and treatment efficiency has been carried out on raw and partially-treated water samples from catchments in the Midlands region of the UK. The catchments cover an area of different water sources, ranging from upland, peaty-rich subcatchments with coloured, young waters, to agriculturally transformed lowland subcatchments. From the spectrophotometric analysis of raw water it was found that, the abstraction from river with water storage in reservoirs corresponds with a hydrophilic character of organic matter, rather high microbial fraction and high TOC. Opposite properties (hydrophobic, low microbial and variable TOC) are specific for sites with abstraction and storage processes within reservoirs. For direct abstraction from rivers, without water storing in reservoir, a common pattern is intermediate character of organic matter. The fluorescence excitation-emission matrix (EEM) technique was used for the assessment of water treatment works performance (TOC removal) and organic matter characterization. The freshwater organic matter exhibits specific fluorescence properties, with increased intensities of fluorescence in some regions of the EEM, resulting from the water origin. Well-documented relationships of fluorescence properties with aromacity, molecular weight, bioavailability, TOC and biochemical oxygen demand were the basis of discrimination of biochemical organic matter properties, and hence drinking water treatment implications. TOC removal was calculated from the decrease in organic matter peak C fluorescence intensity between raw and clarified water samples. The organic matter character therefore determines the TOC removal at different water treatment works. Low TOC removal appears to correlate with high microbial content and variability of the organic matter characterizing riverine sources, whereas stable, high TOC removal corresponds with small microbial fraction of organic matter of low variability (sites with abstraction from reservoirs).
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0428 Carbon cycling (4806)
DE: 0496 Water quality
DE: 1804 Catchment
DE: 1895 Instruments and techniques: monitoring
SC: Biogeosciences [B]
MN: 2007 Fall Meeting