Field tests of a small pilot plant for the removal of arsenic in groundwater using coagulation and filtering

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• 作者：Ulrike Feistel^a ; ^{feistel@htw-dresden.de} ; Philipp Otter^b ; Sylvie Kunz^a ; Thomas Grischek^a ; Jö ; rg Feller^c
• 关键词：Arsenic removal ; In-line electolysis ; Oxidation ; Co-precipitation ; Drinking water supply ; Small community
• 刊名：Journal of Water Process Engineering
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：14
• 期：Complete
• 页码：77-85
• 全文大小：924 K
• 卷排序：14

文摘

Addressing the lack of viable solutions for water treatment in small rural communities, this paper describes the test of a system for the removal of arsenic. The SuMeWa|SYSTEM (AUTARCON GmbH) disinfects water using in-line electrolysis for the production of chlorine. In order to remove arsenic this approach has been extended using chlorine as oxidant for the trivalent arsenic and bivalent iron. Following the adsorption of arsenic on the freshly precipitated iron(hydr)oxide, Greensand plus™ is used for filtration of the co-precipitate. By using a manganese dioxide coated medium, gaps in the chlorine production can be bridged through the reduction of the MnO2, which is later regenerated when sufficient chlorine is available. The first pilot system was tested and evaluated during the period from April to July 2015 at a site in Germany, Niederfrauendorf, where high concentrations of arsenic had been found in groundwater. After adjustments to the initial set-up the system worked stable during the evaluation period at a flow rate of 60 L/h removing on average 96 % of arsenic and 99 % of iron from the groundwater. The system treated groundwater of mean concentrations of total arsenic of 300 μg/L (of which 79 μg/L were dissolved arsenic) and up to a maximum concentration of 990 μg/L and concentrations of iron of 7.1 mg/L. Arsenic was removed to concentrations of 11 μg/L (dissolved arsenic) and iron to concentrations of 0.04 mg/L. Increasing concentration of arsenic in the treated water when running the system without the electrolytic cell has proven that chlorine enhances the removal process through the fast oxidation of the trivalent arsenic compared to aeration. The mean concentration of chloride in the groundwater was 8 mg/L. This was sufficient for a mean chlorine production of 1.3 mg/L used for oxidation and disinfection.Generally the system proved to be robust and worked reliably once the components had been adjusted to the local groundwater quality.