Chlorides in the wastewater with high concentration seriously interrupts the determination of chemical oxygen demand (COD).Microwave digestion method was used to test COD of wastewater with high chlorine.The experiment results show that for this method,the effect of C1-is weaker than that by traditional potassium dichromate method.As the concentration of C1-is between 0 ～ 30 000 mg/L and COD≤500 mg/L,a certain amount of mercuric sulfate would be added during the COD test,and fractional error of test result is less than ± 5％,which was in the scope of national standard.When the COD of shell gas fracturing flow-back fluid was tested,the effect of C1-on the COD test would be eliminated by using microwave digestion method and the test results was accurate and reliable.%高氯废水中氯离子的存在会严重干扰COD的测定.本文采用微波消解法测定高氯废水的COD,结果表明,采用此方法时氯离子对COD测定结果的影响小于传统重铬酸盐法.当氯离子质量浓度在0～30 000 mg/L、COD≤500 mg/L时,可添加一定量的硫酸汞进行COD的测定,相对误差≤士5％,满足国标允许范围.对实际水样页岩气压裂返排液进行测定时,微波消解法能够消除CI-对COD测定干扰,测定结果准确可靠.
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