珠江三角洲湖库水体嗅味物质分布及其去除

Distribution of odor and taste compounds in the lakes and reservoirs of Pearl River Delta and the removal efficiency in source discharges

采用固相微萃取-气质联用技术对珠江三角洲9个城市共48个湖库水体中的土臭素(GSM)、2-甲基异茨醇(MIB)和2,3,6-三氯苯甲醚(TCA)等5种嗅味物质进行检测,并探讨污水处理厂和自来水厂处理工艺中嗅味物质的浓度变化规律,同时研究强化混凝沉淀工艺对嗅味物质的去除效果.结果表明:珠江三角洲湖库水体中嗅味问题最严重的是广州、佛山、肇庆、东莞、惠州和深圳6个城市,各市湖库的嗅味物质平均浓度为70.93～116.61 ng/L;中山、珠海与江门3个城市的嗅味问题不明显,各市湖库的嗅味物质平均浓度为22.78～58.82 ng/L;珠江三角洲的湖库中浓度最高的嗅味物质是MIB、TCA和GSM,这3种嗅味物质占了嗅味物质总浓度的80.18%～100.00%;污水处理厂和自来水厂中的处理工艺对嗅味物质均有一定的去除效果,嗅味物质的去除主要发生在混凝沉淀阶段;污水处理厂对MIB、TCA和GSM的平均去除率分别为53.55%、57.40%和72.90%;自来水厂对MIB、TCA和GSM的平均去除率分别为64.14%、69.63%和36.86%;强化混凝沉淀实验中,当嗅味物质初始浓度为200 ng/L时,Al2O3投加量为13.75 mg/L可使得混凝沉淀工艺对嗅味物质的去除效果最佳且保证铝盐不超标,嗅味物质浓度增大时Al2O3投加量也需增大;反应体系的p H值处于5～8时,混凝沉淀工艺对嗅味物质的去除效果最佳;混凝搅拌速率越快,嗅味物质的去除率越高且越快达到稳定.

With the continuous improvement of people's living standards,residents put forward higher requirements for water quality,and pay more attention to odor and taste problem.Concentrations of odor and taste compounds in 48 lakes and reservoirs of 9 cities in Pearl River Delta were detected with the method of Solid Phase MicroExtraction-Gas Chromatography/Mass Spectrometry(SPME-GC/MS)technique.The changes of odor and taste compounds concentrations along the water treatment processes of wastewater treatment plants and water supply plants,as well as the removal effect of odor and taste compounds by enhanced coagulation-sedimentation process were studied.The results showed that:the most serious stench problem was the lakes and reservoirs of Guangzhou,Foshan,Zhaoqing,Dongguan,Huizhou and Shenzhen.The average concentrations of odor and taste compounds in the lakes and reservoirs of these 6 cities were from 70.93 to 116.61 ng/L.And the stench problem was not obvious in the lakes and reservoirs of Zhongshan,Zhuhai and Jiangmen.The average concentrations of odor and taste compounds in the lakes and reservoirs of these 3 cities were from 22.78 to 58.82 ng/L.2-methylisoborneol(MIB),2,3,6-trichloroanisole(TCA)and Geosmin(GSM)were the main odor and taste compounds in all lakes and reservoirs,which accounted for 80.18%-100.00%of total odor and taste compounds.The water treatment progresses of wastewater treatment plants and water supply plants could considerably remove odor and taste compounds.Coagulation-sedimentation process had the greatest contribution to the removal of odor and taste compounds.In the wastewater treatment plants,the average removal rates of MIB,TCA and GSM were 53.55%,57.40%and 72.90%,respectively.In the water supply plants,the average removal rates of MIB,TCA and GSM were 64.14%,69.63%and 36.86%,respectively.In the enhanced coagulation-sedimentation experiment,for the initial concentrations of odor and taste compounds of 200 ng/L,coagulation-sedimentation process could reach the greatest removal effect of them,and aluminum was not excessive as well when the coagulant(Al2O3)dosage was 13.75 mg/L.When the concentrations of odor and taste compounds increase,the dosage of Al2O3 should increase,too.When the pH value of the reaction system was between 5 and 8,coagulation-sedimentation process could reach the greatest removal effect of odor and taste compounds.The faster the stirring rate of coagulation was,the higher the removal rate of odor and taste compounds reached,and the faster the stability reached.