摘要
针对饮用水源中锰及氨氮复合污染问题,研究了次氯酸钠(NaClO)、高铁酸钾(K2FeO4)、NaClO联用K2FeO43种预氧化方式强化混凝工艺的去除效果,考察了氧化剂投加量、预氧化时间及pH值对锰、氨氮去除率的影响,并比较了3种预氧化方式消毒副产物(DBPs)的生成量。结果表明,当锰和氨氮的质量浓度分别为1.0 mg/L、0.8 mg/L时,联用方式最佳的反应条件为pH=7,NaClO投加量7.5 mg/L,K2FeO4投加量6 mg/L,预氧化时间10 min,此时锰和氨氮去除率分别达到98.0%、45.5%,出水水质能满足锰质量浓度低于0.1 mg/L、氨氮质量浓度低于0.5 mg/L的要求。通过正交试验确定氧化剂投加量和pH值是影响联用方式除锰及氨氮的主要因素,预氧化时间则影响不大。与单独投加NaClO相比,联用工艺减少了DBPs的生成量,其中三氯甲烷、三氯乙腈、二氯一溴甲烷的质量浓度分别降低56.5%、55.2%、51.6%。
This paper intends to take its aim to introduce a new method for treating the drinking water contaminated by manganese(Mn^(2+))and ammonia-nitrogen(NH4^+-N)by enhancing the coagulation process through pre-oxidation.To achieve the purpose,we have made a comparison of 3 different pre-oxidation methods in removing efficiencies of manganese and ammonia-nitrogen by using the sodium hypochlorite,potassium ferrate and sodium hypochlorite combined with potassium ferrate.What is more,we have also made a comparison of the amount of disinfection by-products(DBPs),in combination of tracing the effects of pH value,the sodium hypochlorite dosage,the potassium ferrate dosage and the pre-oxidation time on the manganese and ammonia-nitrogen removal efficiencies.The results of our investigation demonstrate that the conventional coagulation process has just limited function on the manganese and ammonia-nitrogen removal,though being profitable in turbidity removal approach.For instance,when the mass concentrations of manganese and ammonia-nitrogen were 1.0 mg/L and 0.8 mg/L,the removal efficiencies of manganese and ammonia-nitrogen could only go up at about 92.0%and 40.2%by adding 10.0 mg/L of available chlorine,though,the pre-chlorination can manage to decrease the toxicological safety of the drinking water by giving off massiveDBPs product.The removal efficiencies of manganese and ammonia-nitrogen were 97.0%and 17.5%by adding 12.0 mg/L potassium ferrate.Moreover,the potassium ferrate proves an environmentally friendly oxidant that does not produce any carcinogenic/mutagenic by-products.Since available chlorine and potassium ferrate could help to effectively treat ammonia-nitrogen and manganese,respectively,sodium hypochlorite can be used cooperatedly with potassium ferrate to remove the manganese and ammonia-nitrogen to reduce the amount of DBPs.To be exact,it is possible to make the removal efficiencies of manganese and ammonia-nitrogen so high as up to 98.0%and 45.5%under the condition of 7.5 mg/L effective chlorine,6.0 mg/L potassium ferrate,at pH=7,through 10 minutes of pre-oxidation.The effluent concentrations both for manganese and ammonia-nitrogen can be made to reach below the demands of 0.1 mg/L for manganese and less than 0.5 mg/L for ammonia-nitrogen,respectively.Therefore,as compared with sodium hypochlorite used as the pre-oxidant,the combination of sodium hypochlorite and potassium ferrate can help to reduce the amount of DBPs conspicuously.Furthermore,the mass concentrations of trichloromethane,trichloroacetonitrile and bromodichloromethane can thus be made fall to 56.5%,55.2%and 51.6%,respectively.
作者
许仕荣
吴小芳
黄茂林
杨学伟
XU Shi-rong;WU Xiao-fang;HUANG Mao-lin;YANG Xue-wei(College of Civil Engineering,Hunan University,Changsha 410082,China;China Machinery International Engineering Design & Research Institute Co. Ltd.,Changsha 410007,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2019年第4期1341-1348,共8页
Journal of Safety and Environment
基金
中国机械设备工程股份有限公司科技研发基金支持项目(CMEC-KJYF-2015-04)
中机国际工程设计研究院有限责任公司科技研发基金支持项目
关键词
环境工程学
锰与氨氮复合污染
次氯酸钠
高铁酸钾
消毒副产物
environmental engineering
combined pollution of manganese and ammonia-nitrogen
sodium hypochlorite
potassium ferrate
disinfection by-products
