Journal of South China University of Technology (Natural Science Edition) ›› 2017, Vol. 45 ›› Issue (11): 132-138.doi: 10.3969/j.issn.1000-565X.2017.11.019

• Environmental Science & Technology • Previous Articles     Next Articles

Simultaneous Removal of Soluble Silicate，Iron and Manganese in Groundwater

TAO Hui1,2,3 LAI Lian-hua1,2 CHEN Qing3 BAI Xin-zheng3   

  1. 1,Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of the Ministry of Education，Hohai University,Nanjing 210098,Jiangsu,China; 2.College of Environment,Hohai University,Nanjing 210098,Jiangsu,China; 3.Suzhou Litree Water Purification Technology Co.,Ltd.,Suzhou 215152,Jiangsu,China
  • Received:2017-02-21 Revised:2017-07-07 Online:2017-11-25 Published:2017-10-01
  • Contact: 陶辉(1981-)，男，博士，副教授，主要从事饮用水处理研究． E-mail:taohui@hhu.edu.cn
  • About author:陶辉(1981-)，男，博士，副教授，主要从事饮用水处理研究．
  • Supported by:
    Supported by the National Key R＆D Program of China(2016YFC0400803) and the Fund of Major Science and Technology Program for Water Pollution Control and Treatment(2014ZX07405)

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Abstract: In face with the situation in which soluble silicate,Fe(Ⅱ) and Mn(Ⅱ) simultaneously exceed the standards of the groundwater in a certain area,a study has been performed of aeration + ferric chloride，sodium hy- pochlorite + ferric chloride,aeration + calcium hydroxide，sodium hypochlorite + calcium hydroxide and aeration + sodium hypochlorite coupled with ferric chloride to realize the simultaneous removal of the soluble silicate，Fe(Ⅱ) and Mn(Ⅱ).The results of the aeration oxidation method show that (1) a satisfactory simultaneous removal effect of silicon,iron and manganese cannot be obtained with ferric chloride being the coagulant; (2) with calcium hy- droxide being the coagulant,this simultaneous removal can be achieved (when the dosage of calcium hydroxide is 500mg/L,the removal rates of the soluble silicate，Fe(Ⅱ) and Mn(Ⅱ) are 51. 2%,84. 3% and 90. 9%,re- spectively),but with a result of pH value surpassing the standard; and (3) application of the sodium hydroxide/ ferric chloride compound coagulant can improve the simultaneous removal effect of silicon,iron and manganese with a effluent turbidity being less than 0. 71NTU,and the pH value of the effluent can also meet the requirements of wa- ter quality.The results with sodium hypochlorite as the oxidant indicate that using ferric chloride as the coagulant can effectively remove iron and manganese,but the removal efficiencies of the silicon and the effluent turbidity are poor,and that,with calcium hydroxide being the coagulant,silicon,iron and manganese can be simultaneously removed with a lower effluent turbidity,but the pH value of the effluent is too high to meet the requirements of water quality.To sum up,it is recommended to adopt the aeration oxidation +calcium hydroxide/ferric chloride compound coagulant as the simultaneous removal method of silicon，iron and manganese in the groundwater.When the calcium hydroxide dosage is 500mg/L and the ferric chloride dosage (calculated with Fe3+ ) is 22. 4mg/L,the residual silicon,iron and manganese contents (with an effluent turbidity being less than 0. 65NTU and a pH value being 8. 5) in the efflu- ent are 13. 74,0. 15,0. 005mg/L,respectively,which can meet the requirements of drinking water health standards.

Key words: water treatment, groundwater, soluble silicate, iron, manganese, simultaneous removal