不同功能区污水中汞的含量、形态和负荷研究

Contents,Speciation and Loads of Mercury in Municipal Sewage Discharged from Various Functional Areas

该研究以焦作市5种不同功能区(居民区、商业区、学校、牙科诊所和医院)的污水作为研究对象,分析了其中汞的浓度和形态,进而对不同功能区污水的汞负荷进行了估算。结果显示,牙科诊所污水中的总汞(THg)和甲基汞(MeHg)浓度最高,均值分别为(11.3±10.6)μg/L和(18.17±31.76)ng/L。医院污水样品THg和MeHg浓度均值分别为(324.70±274.22)ng/L和(6.84±3.85)ng/L。居民区、商业区和学校的污水中THg的浓度相差不大,均值分别为(179.15±54.20)、(256.04±123.93)和(156.65±42.63)ng/L;MeHg浓度分别为(2.42±0.71)、(2.67±1.68)和(1.80±0.40)ng/L。所有样品中,溶解态总汞(DTHg)占THg的比例为0.74%~23.37%之间,溶解态甲基泵(DMeHg)占MeHg的比例为23.41%~45.70%,说明污水中的汞主要以颗粒态存在;污水样品MeHg占THg的比例为1.10%~4.48%。牙科诊所的污水中,THg和MeHg的浓度都很高,需要采取有效措施减少牙科污水中汞的排放。以居民区、商业区、学校生活污水汞浓度的均值来估算,全国城镇生活污水的THg负荷为(6.41±1.68)t/a,相当于全国城市污泥THg负荷的(52.54±13.77)%,是城市污水中汞的主要贡献源。以牙科医生的平均THg负荷计算,全国牙科污水的THg负荷为(193.13±198.01)kg/a,对全国城市污泥THg负荷的贡献率约为(1.58±1.62)%;以医院床位的平均THg负荷计算,全国医院污水的THg负荷为(142.53±224.22)kg/a,对全国污泥中THg负荷的贡献率约为(1.17±1.84)%,可见牙科诊所污水和医院污水不是城市污水中汞的主要贡献源。

Municipal sewage samples were collected from five functional areas(residential area,commercial area,school,dental clinic and hospital)in Jiaozuo City,Henan Province.Concentrations of mercury(Hg)species in the sewage samples were analyzed,and the corresponding mercury loads were calculated.The results showed that the concentrations of total Hg(THg)and methylmercury(MeHg)were the highest in dental sewage,(11.3±10.6)μg/L and(18.17±31.76)ng/L,respectively.The concentration of THg and MeHg was(324.70±274.22)ng/L and(6.84±3.85)ng/L in hospital sewage samples.The concentrations of THg in sewage from residential areas,commercial areas and schools were not significantly different from each other,showing averages of(179.15±54.20)ng/L,(256.04±123.93)ng/L and(156.65±42.63)ng/L,the MeHg concentra⁃tion was(2.42±0.71)ng/L,(2.67±1.68)ng/L and(1.80±0.40)ng/L,respectively.In all the samples,the dissolved THg(DTHg)accounted for 0.74%~23.37%of THg and DMeHg accounted for 23.41%~45.70%of MeHg,indicating that Hg in the sewage samples occurred mainly in the particulate phase.MeHg accounted for 1.10%~4.48%of THg in the sewage samples.High concentrations of Hg in dental clinic sewage call for effective methods to reduce Hg discharge from dental sewage.Based on the average THg concentration of sewage from residential areas,commercial areas and schools,the national domestic sewageborne THg load was estimated to be(6.41±1.68)t/a,accounting for(52.54±13.77)%of sludge-borne,which is main source of mercury in urban sewage.Based on the average THg load of dentists,the THG load of national dental sewage was(193.13±198.01)kg/a,accounting for(1.58±1.62)%of sludge-borne;Based on the average THG load of hospital beds,the THG load of national hospital sewage was(142.53±224.22)kg/a,accounting for(1.17±1.84)%of sludge-borne,which shows that dental sewage and hospital sewage are not the main contribution sources of mercury in urban sewage.