title: Use of drinking water treatment solids for arsenate removal from desalination concentrate.
abstract: Desalination of impaired water can be hindered by the limited options for concentrate disposal. Selective removal of specific contaminants using inexpensive adsorbents is an attractive option to address the challenges of concentrate management. In this study, two types of ferric-based drinking water treatment solids (DWTS) were examined for arsenate removal from reverse osmosis concentrate during continuous-flow once-through column experiments. Arsenate sorption was investigated under different operating conditions including pH, arsenate concentration, hydraulic retention time, loading rate, temperature, and moisture content of the DWTS. Arsenate removal by the DWTS was affected primarily by surface complexation, electrostatic interactions, and arsenate speciation. Results indicated that arsenate sorption was highly dependent on initial pH and initial arsenate concentration. Acidic conditions enhanced arsenate sorption as a result of weaker electrostatic repulsion between predominantly monovalent H2AsO4(-) and negatively charged particles in the DWTS. High initial arsenate concentration increased the driving force for arsenate sorption to the DWTS surface. Tests revealed that the potential risks associated with the use of DWTS include the leaching of organic contaminants and ammonia, which can be alleviated by using wet DWTS or discarding the initially treated effluent that contains high organic concentration.
authors.affiliation: Department of Civil Engineering, New Mexico State University, NM 88003, United States.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Civil Engineering, New Mexico State University, NM 88003, United States.
authors.forename: Lu
authors.initials: L
authors.lastname: Lin
authors.affiliation: Department of Civil Engineering, New Mexico State University, NM 88003, United States.
authors.forename: Charalambos
authors.initials: C
authors.lastname: Papelis
authors.affiliation: Department of Civil Engineering, New Mexico State University, NM 88003, United States.
authors.forename: Maung
authors.initials: M
authors.lastname: Myint
authors.affiliation: Department of Civil and Environmental Engineering, Colorado School of Mines, CO 80401, United States.
authors.forename: Tzahi Y
authors.initials: TY
authors.lastname: Cath
authors.affiliation: Department of Civil Engineering, New Mexico State University, NM 88003, United States. Electronic address: pxu@nmsu.edu.
authors.forename: Pei
authors.initials: P
authors.lastname: Xu
mesh_terms: D000327:Adsorption; D001149:Arsenates / Q000302:isolation & purification*; D060766:Drinking Water / Q000032:analysis*; D004867:Equipment Design; D005290:Ferric Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009995:Osmosis; D054712:Salinity; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000295:instrumentation*
chemical_list: D001149:Arsenates; D060766:Drinking Water; D005290:Ferric Compounds; D014874:Water Pollutants, Chemical; C025657:arsenic acid
keywords: Arsenate removal; Arsenic; Desalination concentrate; Drinking water treatment solids; Sorption