title: Comparison of sand-based water filters for point-of-use arsenic removal in China.
abstract: Contamination of groundwater wells by arsenic is a major problem in China. This study compared arsenic removal efficiency of five sand-based point-of-use filters with the aim of selecting the most effective filter for use in a village in Shanxi province, where the main groundwater source had arsenic concentration >200 μg/L. A biosand filter, two arsenic biosand filters, a SONO-style filter and a version of the biosand filter with nails embedded in the sand were tested. The biosand filter with embedded nails was the most consistent and effective under the study conditions, likely due to increased contact time between water and nails and sustained corrosion. Effluent arsenic was below China's standard of 50 μg/L for more than six months after construction. The removal rate averaged 92% and was never below 86%. In comparison, arsenic removal for the nail-free biosand filter was never higher than 53% and declined with time. The arsenic biosand filter, in which nails sit in a diffuser basin above the sand, performed better but effluent arsenic almost always exceeded the standard. This highlights the positive impact on arsenic removal of embedding nails within the top layer of biosand filter sand and the promise of this low-cost filtration method for rural areas affected by arsenic contamination.
authors: RISE, Tsinghua University, Beijing 100084, China; School of Environment, Tsinghua University, Beijing 100084, China.
authors: Kate
authors: K
authors: Smith
authors: School of Environment, Tsinghua University, Beijing 100084, China.
authors: Zhenyu
authors: Z
authors: Li
authors: College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, China.
authors: Bohan
authors: B
authors: Chen
authors: College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
authors: Honggang
authors: H
authors: Liang
authors: RISE, Tsinghua University, Beijing 100084, China; School of Environment, Tsinghua University, Beijing 100084, China.
authors: Xinyi
authors: X
authors: Zhang
authors: RISE, Tsinghua University, Beijing 100084, China; School of Social Sciences, Tsinghua University, Beijing 100084, China.
authors: Ruifei
authors: R
authors: Xu
authors: College of Computer Science and Technology, Taiyuan University of Technology, Taiyuan 030024, China.
authors: Zhilin
authors: Z
authors: Li
authors: RISE, Tsinghua University, Beijing 100084, China; School of Environment, Tsinghua University, Beijing 100084, China.
authors: Huanfang
authors: H
authors: Dai
authors: RISE, Tsinghua University, Beijing 100084, China; School of Environment, Tsinghua University, Beijing 100084, China.
authors: Caijie
authors: C
authors: Wei
authors: School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: shumingliu@tsinghua.edu.cn.
authors: Shuming
authors: S
authors: Liu
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000032:analysis*; D002681:China; D004867:Equipment Design; D005374:Filtration / Q000295:instrumentation / Q000379:methods*; D060587:Groundwater / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*; D060753:Water Quality; D060986:Water Wells
chemical_list: D014874:Water Pollutants, Chemical; D012822:Silicon Dioxide; D007501:Iron; D001151:Arsenic
keywords: Biosand filter; Contamination; Drinking water; Iron; SONO filter