title: Changes in the quality of river water before, during and after a major flood event associated with a La Niña cycle and treatment for drinking purposes.
abstract: The treatment of organics present in the lower reaches of a major river system (the Murray-Darling Basin, Australia) before (March-July 2010), during (December 2010-May 2011) and after (April-December 2012) a major flood period was investigated. The flood period (over 6months) occurred during an intense La Niña cycle, leading to rapid and high increases in river flows and organic loads in the river water. Dissolved organic carbon (DOC) increased (2-3 times) to high concentrations (up to 16mg/L) and was found to correlate with river flow rates. The treatability of organics was studied using conventional jar tests with alum and an enhanced coagulation model (mEnCo©). Predicted mean alum dose rates (per mg DOC) were higher before (9.1mg alum/mg DOC) and after (8.5mg alum/mg DOC) than during the flood event (8.0mg alum/mg DOC), indicating differences in the character of the organics in raw waters. To assess the character of natural organic matter present in raw and treated waters, high performance size exclusion chromatography with UV and fluorescence detectors were used. During the flood period, high molecular weight UV absorbing compounds (>2kDa) were mostly detected in waters collected, but were not evident in waters collected before and afterwards. The relative abundances of humic-like and protein-like compounds during and following the flood period were also investigated and found to be of a higher molecular weight during the flood period. The treatability of the organics was found to vary over the three climate conditions investigated.
authors.affiliation: Centre for Water Management and Reuse, Natural and Built Environments University of South Australia, SA 5095, Australia.
authors.forename: Mohamad Fared
authors.initials: MF
authors.lastname: Murshed
authors.affiliation: Centre for Water Management and Reuse, Natural and Built Environments University of South Australia, SA 5095, Australia.
authors.forename: Zeeshan
authors.initials: Z
authors.lastname: Aslam
authors.affiliation: Centre for Water Management and Reuse, Natural and Built Environments University of South Australia, SA 5095, Australia.
authors.forename: Rosmala
authors.initials: R
authors.lastname: Lewis
authors.affiliation: Centre for Water Management and Reuse, Natural and Built Environments University of South Australia, SA 5095, Australia; Australian Water Quality Centre, South Australian Water Corporation, SA 5000, Australia; State Key Laboratory for Environmental Aquatic Chemistry, Research Centre for Eco-Environmental Sciences, Beijing 100085, China.
authors.forename: Christopher
authors.initials: C
authors.lastname: Chow
authors.affiliation: Centre for Water Management and Reuse, Natural and Built Environments University of South Australia, SA 5095, Australia; State Key Laboratory for Environmental Aquatic Chemistry, Research Centre for Eco-Environmental Sciences, Beijing 100085, China.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Wang
authors.affiliation: Centre for Water Management and Reuse, Natural and Built Environments University of South Australia, SA 5095, Australia; Australian Water Quality Centre, South Australian Water Corporation, SA 5000, Australia; State Key Laboratory for Environmental Aquatic Chemistry, Research Centre for Eco-Environmental Sciences, Beijing 100085, China.
authors.forename: Mary
authors.initials: M
authors.lastname: Drikas
authors.affiliation: Centre for Water Management and Reuse, Natural and Built Environments University of South Australia, SA 5095, Australia; Barbara Hardy Institute, Natural and Built Environments, University of South Australia, SA 5095 Australia; State Key Laboratory for Environmental Aquatic Chemistry, Research Centre for Eco-Environmental Sciences, Beijing 100085, China. Electronic address: john.vanleeuwen@unisa.edu.au.
authors.forename: John
authors.initials: J
authors.lastname: van Leeuwen
mesh_terms: D002244:Carbon / Q000032:analysis; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002980:Climate; D060766:Drinking Water; D055868:Floods; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D045483:Rivers; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D060766:Drinking Water; D002244:Carbon
keywords: Alum; Coagulation; Flood; La Niña; mEnCo prediction dose (EnCD)