不同来源废水COD、TOC与Cl^-的关系

通过对含盐化工废水（A）、受潮汐影响的河流水（B）、城市生活污水处理厂排水（C）、采油废水（D）4种不同来源废水进行为期15 d的采样监测,测定了其COD、TOC和Cl^-浓度,分析比较了3种废水指标之间的关系,其中COD分别使用重铬酸钾法、氯气校正法和碘化钾碱性高锰酸钾法3种方法进行测定。实验结果表明,4种废水Cl^-浓度差异较大,盐化工废水A（21749 mg/L）〉采油废水D（7013 mg/L）〉受潮汐影响的河流水B（1807 mg/L）〉城市生活污水处理厂排水C（977 mg/L）;在15 d的监测周期内,盐化工废水（A）的TOC波动较大,其余3种废水的TOC浓度基本保持稳定,与Cl^-浓度变化没有直接的关系;4种不同废水的COD与Cl^-浓度之间具有显著的正相关性。通过分析比较表明,碘化钾碱性高锰酸钾法比较适合于盐化工废水（A）和采油废水（D）的测定,氯气校正法比较适合于城市生活污水处理厂排水（C）和采油废水（D）的测定,受潮汐影响的河流水样（B）波动较大,3种方法测得的COD浓度与Cl^-浓度的变化趋势没有显著差异。TOC较适合表征水质有机污染程度。

Correlations between chlorine ion,COD and TOC in wastewaters from different sources

The wastewaters from different sources,such as high salinity chemical wastewater（A）,tide-affected river water（B）,municipal sewage（C） and oil production wastewater were monitored for a period of 15 days,COD,TOC and Cl^-concentrations were determined and the relationship between them was investigated.The COD was measured by dichromate method,chlorine emendation method and potassium iodide alkaline permanganate method,respectively.The results showed that,there was a large difference among the Cl^-concentrations of the samples,which was in order of A（21 749 mg/L）〉D（7 013 mg/L）〉B（1 807 mg/L）〉C（977 mg/L）.During the 15 days monitoring periods,the TOC values of high salinity chemical wastewater（A） fluctuated widely while the TOC of the other three kind wastewater remained stable,and there was no direct correlations between TOC and chloride ion concentration.The COD values of all four samples showed a significant positive relation with the Cl^-concentration.It could be concluded that potassium iodide alkaline permanganate method was more suitable for determining COD in wastewater A and D,and chlorine emendation method was suitable for determining COD in wastewater C and D.As water in tidal river fluctuated widely,there was no significant difference among the COD values measured by three methods according to the Cl^-concentration.TOC was more suitable for characterizing the organic pollution degree of water quality.