摘要
针对反渗透浓盐水中的高COD_(Cr)、高盐特点,提出深度处理及排放资源回收方案为化学软化-高级氧化-超滤-树脂软化-高压反渗透-纳滤分盐-电渗析浓缩-双极膜电渗析酸碱再生。重点考察了化学软化、高级氧化、树脂软化以及电渗析和双极膜电渗析满足处理要求时的最佳操作参数。结果表明,化学软化最优加药量为理论值的1.2倍,使Ca^(2+)、Mg^(2+)质量浓度分别降低为3.29、2.04 mg/L,满足树脂软化硬度进水要求;高级氧化对比了O_(3)催化氧化、Fenton氧化、O_(3)/H_(2)O_(2)复合氧化的效果,其中O_(3)/H_(2)O_(2)复合氧化效果最优,反应1.0 h,COD_(Cr)去除率为66.41%,出水COD_(Cr)质量浓度<100 mg/L,满足树脂软化及后续膜系统进水要求;SO^(2-)_(4)的存在会降低树脂软化硬度去除效率,且含盐量超过20 g/L时树脂软化效果开始下降,因系统树脂软化进水中含盐量<20 g/L,故为了防止纳滤膜结垢,将纳滤分盐设置在树脂软化之后;为了防止能耗过高,电渗析浓水中含盐量仅需达到150 g/L即可,在此浓度下,双极膜电渗析在反应180 min时,产酸、碱量可达到73.2、78.5 g/L;其次,当电流密度为50 mA/cm2、反应120 min时,酸、碱能耗分别为3.1、2.7 kW·h/kg。
According to the characteristics of high COD_(Cr)and high salt in reverse osmosis concentrated brine,the advanced treatment and emission resource recovery scheme was proposed as follows:chemical softening-advanced oxidation-ultrafiltration-resin softening-high pressure reverse osmosis-salt separation by nanofiltration-electrodialysis concentration-acid-base regeneration by bipolar membrane electrodialysis.The optimum operating parameters of chemical softening,advanced oxidation,resin softening,electrodialysis and bipolar membrane electrodialysis were investigated.Results showed that the optimum dosage of chemical softening was 1.2 times of the theoretical value,which reduced the content of Ca^(2+)and Mg^(2+)to 3.29 mg/L and 2.04 mg/L,respectively,reaching the requirements of resin softening hardness.Advanced oxidation compared the effects of O_(3)catalytic oxidation,Fenton oxidation and O_(3)/H_(2)O_(2)composite oxidation.Among them,the effect of O_(3)/H_(2)O_(2)composite oxidation was the best.The reaction time was 1.0 h,the COD_(Cr)removal rate was 66.41%,and the effluent COD_(Cr)mass concentration was less than 100 mg/L,which met the requirements of resin softening and subsequent membrane system water inlet.The existence of SO^(2-)_(4) would reduce the removal efficiency of resin softening hardness,and the resin softening effect began to decline when the salt content exceeded 20 g/L.Because the system resin softening inlet water was less than 20 g/L,in order to prevent the scaling of nanofiltration membrane,the nanofiltration salt was set after the resin softening.In order to prevent excessive energy consumption,the concentrated water of electrodialysis only need to reach 150 g/L.At this concentration,the acid and base production of bipolar membrane electrodialysis could reach 73.2 g/L and 78.5 g/L when reacted for 180 min.Secondly,when the current density was 50 mA/cm^(2),reaction time was 120 min,the energy consumption of acid and base was 3.1 kW·h/kg and 2.7 kW·h/kg,respectively.
作者
王强
韦凤密
李雅
陶莉
王立媛
刘晨明
WANG Qiang;WEI Fengmi;LI Ya;TAO Li;WANG Liyuan;LIU Chenming(Beijing Cycle Columbus Environmental Science and Technology Co.,Ltd.,Beijing 100088,China;Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China)
出处
《净水技术》
CAS
2023年第3期127-135,共9页
Water Purification Technology
关键词
浓盐水
高级氧化
双极膜电渗析
酸碱再生
零排放
concentrated brine
advanced oxidation
bipolar membrane electrodialysis
acid-base regeneration
zero discharg
