盐析 -蒸发法处理喷漆废水

针对喷漆废水化学需氧量（ COD）高、生物毒性大的特点，采用盐析 -蒸发工艺进行处理，考察了无机盐的种类及投加量、温度、静置时间和蒸发重相循环次数等主要因素对废水处理效果的影响。结果表明：在温度为 60 ℃、碳酸钠质量浓度为 400 g/L、静置时间为 3h的最佳工艺条件下， COD去除率高达 96. 5%；在重相循环 8次后， COD去除率稳定在 89. 3%，废水五日生化需氧量与化学需氧量的比值（ BOD₅/COD）从 0. 09升至 0. 68，可生化性大大提高。

Treatment of Paint Overspray Wastewater by Salting Out-Evaporation Method

The treatment process of salting out-evaporation was used to treat the paint overspray wastewater because of its high COD and biological toxicity. The influence of the main factors on the treatment efficiency were investigated,such as the kinds and dosage of inorganic salts,the temperature,the log of time,and the evaporation cycle times. The results showed that under the optimized process conditions of temperature 60 ℃,sodium carbonate dosage 400 g/L,log of time 3 h,the COD removal rate was as high as 96. 5% and the COD removal rate was steady at 89. 3% after 8 cycles. The BOD5/COD of wastewater was increased from 0. 09 to 0. 68,and the biodegradability was greatly improved.