城市给水厂常规工艺铬（Ⅵ）去除风险分析与应急处理方法研究

铬（Ⅵ）是突发性水污染常见污染物之一。研究表明，我国给水厂常规工艺出水铬（VI）超标风险较高，当污染强度为0．20m∥L时，投加混凝剂（PAFC）100mg／L，出水铬（VI）浓度为0．10mg／L，无法满足《生活饮用水卫生标准》（GB5749．2006）0．05mg／L的要求。活性炭吸附法不是理想的铬（Ⅵ）应急处理方法，当污染强度为0．114～0．794mg／L时，在未调节原水pH（7～8）的条件下，增加活性炭投加量，去除效果无明显改善，出水铬（Ⅵ）浓度大于0．05mg／L。硫酸亚铁还原沉淀法是可行的铬（Ⅵ）污染应急处理方法，当铬（Ⅵ）污染强度为2．00mg／L，pH为7～8时，投加硫酸亚铁16mg／L，铬（Ⅵ）去除率达99．1％，出水铬（VI）与铁浓度分别为0．019和0．021mg／L，满足标准要求，改变硫酸亚铁投加量可满足不同污染强度下应急处理的需要。

Studies on chromium （ VI ） risk of conventional water treatment process and emergency measures

Chromium（ VI ） is one of the main pollutants in water pollution accidents. It was showed that when the chromium was 0.2 mg/L, effluent chromium（WI） was 0. 10 mg/L, which couldn＇t meet the require- ment of 0.05 mg/L in（（Water Quality Standards for Urban Water Quality））（ GB 5749-2006） , even if coagulation dose was 100 mg/L. It meant large security risk in conventional process. Active carbon adsorption was not an i- deal technology in chromium（WI） emergency. When chromium（ Wl ） was at 0. 114 - 0. 794 mg/L, without ad- justing pH, effluent quality couldn＇ t meet the requirement of standards even if increasing active carbon dose. Reduction-precipitation method of ferrous sulfate was a feasible emergency treatment technology of accidental chromium（WI） pollution. When the chromium（VI） was 2.00 mg/L and pH was at 7 - 8, the removal rate of chromium（ WI ） is 99.1% at ferrous sulfate dose of 16 mg/L. And the effluent concentrations of chromium and i- ron were 0. 019 and 0. 021 mg/L, respectively, which could meet the requirement of standards. Under several pollution intensities conditions, chromium（WI） of effluent was below 0.05 mg/L by changing ferrous sulfate dose.