高浓度机械加工清洗废水预处理工艺研究

Research on the pretreatment process of highly concentrated mechanical cleaning wastewater

针对COD高达300 000 mg/L的机械加工清洗废水,采用破乳—热解—铁炭微电解—Fenton氧化联合工艺进行处理。研究结果表明:加入10 g/L的Al2(SO4)3破乳后,热解20 min的处理效果最好;铁炭微电解最佳条件为:维持p H至3.5,铁屑20 g/L,铁炭质量比为1∶1,反应时间4 h;Fenton氧化最佳条件为:维持p H至3.5,30%H2O2投加量为20 m L/L,反应时间4 h,再调节p H至9后沉淀,处理后废水COD可降为20 000 mg/L。

Aiming at the mechanical cleaning wastewater,whose COD is 300 000 mg/L,it has been treated by the combined process,demulsification-pyrolysis-iron-carbon micro-electrolysis-Fenton oxidation. The research results show that the treatment effect is the best after the Al2（SO4）3whose concentration is 10 g/L is demulsified and then pyrolyzed for 20 min. The best conditions for iron-carbon micro-electrolysis are as follows：p H stays at 3.5,iron filings is 20 g/L,iron-carbon mass ratio 1∶1,and reaction time 4 h. The best conditions for Fenton oxidation process are as follows：p H is 3.5,dosage of 30% hydrogen peroxide 20 m L/L,reaction time 4 h,and precipitation after the p H is conditioned to 9,the COD of the treated wastewater can be decreased to 20 000 mg/L.