水质化学需氧量(COD)检测技术与系统研究

Detection Technology and System Research on COD On-line Detection System in Water

研究的水质COD在线检测系统是根据朗伯-比尔定律来测试水样COD浓度,系统采用双光路设计,并选用可变光程流通池来满足在不同水体测试的要求。通过本系统检测得到的5组水样COD浓度,对系统测试COD浓度值与已知实验室化学法COD浓度值进行了二者的数值偏差及误差分析。实验结果表明,两者的最大偏差值约为7.93,最小偏差值为0.33,数据的平均偏差值为3.74左右,以及本系统测试结果的平均相对误差为6.72%,标准差为4.66。文中系统测试得到的COD浓度值与其已知浓度值很相近,系统测试结果准确度比较高,能够基本满足检测的需求,并且测量快速、易操作、无污染,适合于在线检测水体COD浓度。

Based on Lambert-Beer＇s law, a chemical oxygen demand（COD） on-line detection system in wateris introduced. Two light path design is adopted in the system and a variable light path length of flow sample cell isused to meet different testing requirements in variable water. The COD concentrations of the system model tested in5 samples are compared to the laboratory chemical ones, and the numerical deviation and error analysis are made.Experimental results show that the maximum deviation value of two sets is 7.93, the minimum deviation value is0.33, and the average deviation is about 3.74. The average relative error of the system is 6.72%, and standard devia-tion is 4.66. Therefore, the COD concentration value tested by the system is much closed to the known COD concen-tration value. The accuracy of the testing result is higher, which meets the requirements of detection. And it has fastspeed detection, easy to operate, no pollution, and is suitable for on-line COD concentration detection in water.