不同pH对危废填埋场渗滤液单效蒸发工艺影响的研究

利用单效蒸发工艺对危废填埋场渗滤液进行预处理,通过改变渗滤液原液的初始pH,研究不同pH条件下,渗滤液在蒸发过程中氯离子、COD、氨氮含量的变化规律。结果表明:单效出水中氯离子的浓度随着pH的增大而升高,但对氯离子的去除率影响不大,均在99%以上;出水中COD的浓度随着pH的增大而降低,在中性及碱性条件下,蒸发过程中COD的去除率明显增加,约96%以上;出水中氨氮的浓度随着pH的增大而升高,在酸性条件下,氨氮的去除率最高,中性条件下氨氮去除率明显降低,碱性条件下氨氮的去除率迅速下降甚至出现负值。通过改变渗滤液原液pH,单效蒸发技术可以同时去除水中的氯离子、COD、氨氮等污染物。

The leachate of hazardous landfill was pretreated by single-effect evaporation process,and the changes of chloride ions,COD and ammonia nitrogen contents of leachate under different pH conditions were studied by changing the initial pH of the leachate stock solution.The results showed that the concentration of chloride ions in single-effect effluent increased with the increase of pH value,but had little effect on the removal rate of chloride ions,all of which were above 99%.The concentration of COD in effluent decreases with the increase of pH,and the removal rate of COD during evaporation increases significantly under neutral and alkaline conditions,about 96%or more.The concentration of ammonia nitrogen in effluent increases with the increase of pH value,and the removal rate of ammonia nitrogen is the highest under acidic conditions,the removal rate of ammonia nitrogen under neutral conditions is significantly reduced,and the removal rate of ammonia nitrogen under alkaline conditions decreases rapidly or even appears negative.By changing the pH of the leachate stock solution,single-effect evaporation technology can simultaneously remove chloride ions,COD,ammonia nitrogen and other pollutants in the water.