title: Reducing natural organic matter and disinfection by-product precursors by alternating oxic and anoxic conditions during engineered short residence time riverbank filtration: A laboratory-scale column study.
abstract: Riverbank filtration (RBF) with days to months of residence time has been successfully used as treatment or pre-treatment process to improve water quality for decades. However, its feasibility depends on the local hydrogeological conditions. Therefore, for sites unsuitable to traditional RBF, a smaller engineered RBF may be an option. This study evaluates the performance of engineered short residence time RBF on improving water quality, focusing on the removal of natural organic matter (NOM) and the reduction of precursors of carbon and nitrogen disinfection by-products (DBP). Lab-scale experiments were conducted with surface feed water from a drinking water plant. The results showed that within 6days hydraulic retention time (HRT), 60-70% dissolved organic carbon (DOC) and 70-80% ultraviolet absorbance at 254nm (UV254) could be removed. During the whole filtration process, biodegradation was responsible for the removal of organic matter, and it was found that alternating redox condition between oxic and anoxic was beneficial for the overall performance of the RBF. Dissolved oxygen (DO) had a substantial impact on the removal of DBP precursors. For carbon-containing DBP (C-DBP) precursors' removal, re-aeration after a sequence of oxic and anoxic conditions could further increase the removal efficiencies from 50%, 60%, and 60% to 80%, 90%, and 80% for trihalomethanes (THMs), chloral hydrate (CH), and haloketones (HKs). Prolonged anoxic conditions were however beneficial for the removal of nitrogen-containing DBP (N-DBP) precursors.
authors.affiliation: Advanced Water Management Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia.
authors.forename: Peng
authors.initials: P
authors.lastname: Liu
authors.affiliation: Advanced Water Management Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia; Catalan Institute for Water Research (ICRA), 17003 Girona, Spain.
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Farré
authors.affiliation: Advanced Water Management Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia.
authors.forename: Jurg
authors.initials: J
authors.lastname: Keller
authors.affiliation: Advanced Water Management Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia; Catalan Institute for Water Research (ICRA), 17003 Girona, Spain; Catalan Institute for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain. Electronic address: wgernjak@icra.cat.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Gernjak
mesh_terms: D019149:Bioreactors; D004203:Disinfection / Q000379:methods*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D045483:Rivers / Q000737:chemistry*; D014873:Water Pollutants / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification / Q000379:methods*; D060753:Water Quality
chemical_list: D014873:Water Pollutants; D010100:Oxygen
keywords: Disinfection by-product precursors; Engineered riverbank filtration; Natural organic matter; Short residence time