反渗透-正渗透组合工艺处理焦化废水中试研究

A pilot-scale study on deep treatment of coking wastewater by reverse osmosis coupled forward osmosis technology

焦化废水可生化性差,含盐量高,且含有氰化物、酚类、多环芳烃、脂肪族类化合物等难生物降解的污染物。前期对二级生化出水已采用IM-Fent氧化-超滤预处理,采用反渗透-正渗透进一步深度处理,探究该组合工艺对焦化废水深度处理的效果。试验结果表明,该焦化废水浊度、COD、氨氮、氯离子和TDS去除率分别为96%~100%、91.8%~99.2%、92.6%~97.58%、95.7%~97.66%和97.4%~98.13%,产水水质优于《工业循环冷却水处理设计规范》(GB/T 50050-2017)中再生水水质指标,可作为厂区生产补充水使用。组合工艺总回收率达到85.25%~97.53%,大大高于单一反渗透的回收率,对实现焦化废水的近零排放具有参考价值。

Coking wastewater contains high salt content and has poor biodegradability,including cyanide,phenols,polycyclic aromatic hydrocarbons,fatty compounds and other pollutants that are difficult to biodegrade.Fenton oxidation combined with ultrafiltration has been used to pre-treat the secondary biochemical effluent in the previous stage.In this experiment,reverse osmosis coupled forward osmosis system was utilized to further desalinate,aiming to explore the treatment effect of the combined process on coking wastewater.It was found that the removal rates of turbidity,COD,ammonia nitrogen,chloride and TDS of coking wastewater by the membrane combination process were 96%~100%,91.8%~99.2%,92.6%~97.58%,95.7%~97.66%and 97.4%~98.13%,respectively.The effluent quality exceeds the reuse water quality standard in the Design code for the treatment of industrial circulating cooling water(GB/T 50050-2017),which could be used as supplementary water in factory production.In addition,the recovery rate of treated coking wastewater reached 85.25%~97.53%,which is greatly higher than that of single reverse osmosis.It is of great significance to realize zero discharge of coking wastewater.