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The effects of current density on the efficiency of aquaculture wastewater treatment by electrochemical technology

  

  1. (1 College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China;
    2 Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture Chinese Academy of  Fishery Sciences, Yellow Sea Fisheries Research Institute, Shandong Qingdao 266071, China;
    3 College of Biosystems  Engineering and Food Science, Zhejiang University, Zhejiang Hangzhou 310058, China;
    4 Qingdao excellent ocean group co. LTD. Shandong Qingdao 266400, China)
  • Online:2018-08-02 Published:2018-04-20

电流密度对电化学处理水产养殖废水效率的影响

  

  1. (1 上海海洋大学水产与生命学院,上海 201306;
    2 农业部海洋渔业可持续发展重点实验室,中国水产科学研究院黄海水产研究所,山东 青岛 266071;
    3 浙江大学生物系统工程与食品科学学院,浙江 杭州 310058
    4 青岛卓越海洋集团有限公司,山东 青岛 266400)
  • 通讯作者: 朱建新(1966—),男,研究员,研究方向:海水鱼类苗种繁育及工厂化养殖技术。E-mail: zhujx@ysfri.ac.cn
  • 作者简介:张鹏(1993—),男,硕士研究生,研究方向:工厂化循环水养殖技术。E-mail: ZP61650298@163.com
  • 基金资助:
    科技部重点专项 (2016YFE0112600);山东省蓝色产业领军人才团队支撑计划

Abstract: In order to study the  effects of current density on the  purification efficiency of the aquaculture wastewater treatment by
electrochemical technology, an experiment was carried out. In this experiment, the effects of four groups of different current densities (2,4,8 and 12 mA/cm2) on nitrogen removal, trichloromethane and current efficiency were investigated, on the basis of which, the generated  by-products and energy consumption were analyzed. The results showed that the removal efficiency of pollutants were obviously accelerated with the rising of current density. With the increase of current density, the removal rate of ammonia nitrogen increased from 46.9% to 97.8%, the removal rate of nitrates increased from 32% to 95.5%, and the COD removal rate increased from 25.7% to 73.1%. The free chlorine generated in electrolysis and the increased oxidation reduction potential played an important role in disinfection of wastewater. Complete sterilization could be achieved after  reacting for 40 minutes under each group of current density. As the free chlorine in water gradually decreased after electrolysis, the number of bacteria began to  exponentially grow. Current efficiency declined from 33.3% to 15.5% as the current density improved from 2 to 12 mA/cm2, which also caused the increasing of water treatment cost. The experiment showed that electrochemical technology has a good effect in treating aquaculture wastewater, and propriate current density has great significance for improving the efficiency of nitrogen removal and reducing energy consumption.

Key words:  electrochemical water treatment technology, aquaculture water, current density, nitrogen removal, disinfection

摘要: 为研究电化学处理中电流密度对养殖水净化效果的影响,重点考察了4组电流密度(2、4、8和12 mA/cm2)对水体脱氮、杀菌消毒、三氯甲烷生成以及电流效率的影响,并在此基础上对产生的副产物、反应能耗等方面展开分析。结果显示:电流密度上升可加快污染物的去除,随着电流密度上升,氨氮(NH4+-N)去除率由46.9%提高到97.8%,亚硝酸盐氮(NO2--N)去除率由32%增至95.5%,化学需氧量(COD)去除率由25.7%升到73.1%;电解过程产生的游离氯和升高的氧化还原电位在杀菌过程中发挥了重要作用;各电流密度下反应40 min均达到100%杀菌率,电解后一段时间内,随着游离氯质量浓度的逐渐下降,细菌数量表现为指数方式增长;电流效率由2 mA/cm2时的33.3%,逐渐下降到12 mA/cm2时的15.5%,电流效率的降低同时导致水处理能耗的增加。研究表明:电化学技术在养殖水处理中发挥良好作用,选择合适的电流密度对提高处理效率和降低能耗有重要意义。

关键词: 电化学水处理技术, 养殖水, 电流密度, 脱氮, 杀菌