摘要
为了探究不同水质对余氯衰减及含碳、含氮消毒副产物生成的影响,文中采用自制局部管段反应器,分别针对来自2个水厂的不同水质的水体,进行了一系列不同初始余氯浓度C0的余氯衰减试验。结果表明,水厂A还原性物质及有机污染物含量更高,水厂B水质整体优于水厂A,其中,水厂B的出厂水平均浑浊度为水厂A的62.5%,CODMn为水厂A的63.3%,总有机碳(TOC)为水厂A的66.6%。不论何种水质,主体水余氯衰减系数kb及管壁余氯衰减系数kw随C0的变化规律与总余氯衰减系数k一致,氯浓度与余氯衰减速率皆呈负相关关系,且水质越差kb越大,kw则与之相反。虽主体水反应在余氯衰减中占主要作用,但余氯与管壁物质的反应以及在管壁的传质扩散作用也不可忽视。水质差的水厂A水体的二氯乙腈(DCAN)和三氯甲烷(TCM)总生成量更高,增长速率也更快。对于2种水质,在氯浓度为较低的1~2 mg/L时,氯浓度的升高对2种消毒副产物生成量的影响更显著。DCAN生成量累积到一定程度后,均出现降低趋势,且水质好的水厂B水体发生DCAN降解的时间早于水质差的水厂A。在初始浓度较高时,浑浊度、TOC和溶解性有机氮(DON)均在一段时间后出现短暂的升高趋势而后趋于稳定,且水厂A水体中TOC和DON浓度整体水平高于水厂B。因此,可将TOC和DON作为含碳和含氮消毒副产物的主要前驱物。
In order to explore the effects of different water quality on residual chlorine decay and the formation of carbonic disinfection by-products(C-DBPs)and nitrogenous disinfection by-products(N-DBPs),self-made tubular reactors were applied in a series of residual chlorine decay experiment containing different initial chlorine concentrations C0 for drinking water with different water quality from two water treatment plants(WTPs).Results showed that WTP A had higher content of reducing substances and organic pollutants,and the overall water quality of WTP B was better than that of WTP A.Among them,average turbidity,CODMn and total organic carbon(TOC)of finished water of WTP B was 62.5%,63.3%and 66.6%of WTP A respectively.Regardless of water quality,the change of bulk residual chlorine decay rate kb and pipe wall residual chlorine decay rate kw were consistent with total residual chlorine decay rate k which was negatively correlated with initial chlorine concentration.Moreover,the worse water quality was,the greater bulk residual chlorine decay rate kb was but kw was on the opposite.Although bulk water reaction plays a major role in the attenuation of residual chlorine,the reaction of residual chlorine with pipe wall material and the effect of mass transfer and diffusion on pipe wall cannot be ignored.Total production of dichloroacetonitrile(DCAN)and chloroform(TCM)in water of WTP A with poor water quality was higher as well as the faster growth rate.For both water qualities,at low chlorine concentrations of 1~2 mg/L,the increase in chlorine concentration had a more significant effect on the production of these DBPs.When the accumulation of DCAN production reached a certain level,it tended to decrease.In addition,DCAN degradation occurred earlier in WTP B with good water quality than in WTP A with poor water quality.When initial concentration was high,turbidity,TOC and dissolved organic nitrogen(DON)all presented a short-term upward trend after a while and then became stable.Moreover,the overall level of TOC and DON concentrations in water of WTP A was higher than that of WTP B.Therefore,TOC and DON can be regarded as the key precursors of C-DBPs and N-DBPs.
作者
刘彩娥
王诗宇
蒋福春
张雪
杨琛栋
林涛
LIU Cai’e;WANG Shiyu;JIANG Fuchun;ZHANG Xue;YANG Chendong;LIN Tao(Changzhou Jintan Water Supply Co.,Ltd.,Changzhou 213200,China;Shanghai Municipal Engineering Design Institute<Group>Co.,Ltd.,Shanghai 200092,China;Suzhou Water Supply Co.,Ltd.,Suzhou 215002,China;College of Environment,Hohai University,Nanjing 210098,China)
出处
《净水技术》
CAS
2021年第9期29-36,共8页
Water Purification Technology
基金
国家自然科学基金(5197080153)
国家水体污染控制与治理科技重大专项(2012ZX07403-001)。
关键词
余氯衰减
初始余氯浓度
二氯乙腈
三氯甲烷
水质指标
水厂
residual chlorine decay
initial chlorine concentration
dichloroacetonitrile(DCAN)
chloroform(TCM)
water quality index
water treatment plant(WTP)