城市再生水回用于浮选的健康风险评价及应急处置

为研究城市再生水回用于浮选的健康风险,以我国某铜钼矿为例,结合矿区职业人群暴露情况,采用定量微生物风险评价的方法(QMRA),评价了城市再生水中粪大肠菌回用于浮选的健康风险,以及臭氧氧化应急处置措施的消毒效果。结果表明:雨季再生水中粪大肠菌浓度明显高于旱季,矿物颗粒中粪大肠菌浓度高于浮选用水;暴露剂量为1 m L,矿物颗粒中粪大肠菌的年感染概率为0.08~0.33,远高于人体最大接受风险(1.7×10~(-2)),所有工位均处于不可接受水平,暴露于浮选用水中粪大肠菌的年感染概率为0~0.35,处于可接受水平的概率为83%,随暴露剂量增加,矿物颗粒和浮选用水中粪大肠菌的年感染概率增加;臭氧氧化应急处理工艺对粪大肠菌的去除率高达99%,有效降低了浮选用水和矿物颗粒中粪大肠菌的健康风险,其年健康风险均处于可接受水平,臭氧氧化应急处置措施能同时兼顾安全卫生指标和浮选指标,可作为城市再生水回用于浮选时应对粪大肠菌健康风险的应急处理技术。

Health risk assessment and the emergency treatment of the sewage reclaimed and reused for flotation

The present study aims to bring about an assessment of the public health risk associated with the use of the reclaimed water in the flotation choice based on the quantitative microbial risk assessment (QMRA) approach.For this purpose,we have collected such reused water samples from the 6 different sites in Wushan copper-molybdenum (Cu-Mo) ores dressing plant at home to monitor the content concentration rate of the fecal coliform both in the reclaimed water and the ore particles by the plate accounting method.And,then,we have managed to estimate the fecal coliform exposure dosages and the probability of the infection to follow the accidental and intentional ingestion of the 1 mL and 100 mL reclaimed water by using the beta-Poisson dose-response model so as to investigate and examine the disinfection effect of the ozone oxidation treatment.The results of our study can be stated as follows:the content concentration rate of the fecal coliform in the reclaimed water sample proves to be higher in the humid seasons than in the dry seasons,for there has been studied and found more fecal coliforms in the flotation water than in the ore particles,with the mean fecal coliform content range standing from 6.3 × 102 CFU/100 mL to 3 × 106 CFU/100 mL (flotation water) in the humid season and from 1.06 × 105 CFU/100 mL to 2.8 × 105CFU/100 mL (ore particles) in the dry one.What is more,even in the dry season,the mean FC hidden rate may still range from 0 to 9.0 × 104 CFU/100 mL (flotation water) and from 1.06 × 103 CFU/100 mL to 2.8 × 103 CFU/100 mL (in the ore particles),respectively.Thus,we have made it clear that even the annual infection probability of the fecal coliform based on the ingestion of 1 mL of ore particles has been found standing from 0.08 to 0.33 during the dry and humid season,much higher than the extremely tolerable level (1.7 × 10-2),which may grow up to the intolerable or even unbearable level for normal human survival.To be exact,the ingestion of 1 mL flotation water implies to range from 0 to 0.35,whereas the greatest tolerable probability rate of the annual risk is 83％ for all the six sites under study.However,the removal rate of the fecal coliform has been increased to the extent of 99％ as a result of ozone oxidation emergency treatment,which helps to reduce the health risk due to the exposure to the flotation water and the ore particles effectively.Thus,the annual infection probability rate has thus been made reduced to the allowable extent.At the same time,the ozone oxidation process has been made greatly relieved both to the flotation indexes and the safely reusable ones.In one word,it has been made controllable and adaptable to deal with the health risk associated with the reuse of such reclaimed water in the flotation process.