军港海水冲厕污水化学耗氧量(COD)指标的分析方法

提出一种军港海水冲厕排放污水COD的分析方法。先微波消解30 min,利用硫酸-重铬酸钾体系将氯离子完全氧化,冷却后再加入0.1 g硫酸银作催化剂,继续微波消解30 min,使绝大部分有机物被氧化,从测得的总表观COD值中减去氯离子表观COD值(从校准曲线中查得),即为所测水样的COD值。试验表明该方法对于[Cl-]≤20 000 mg/L、CODCr=100 mg/L标准溶液的相对误差≤10%,对于军港海水冲厕排放污水的RSD%≤5%。

Analytical Method of Chemical Oxygen Demand(COD) for Toilet-Flushing Sewage with Seawater at Naval Ports

A method was developed to eliminate chlorine interference in the analysis of chemical oxygen demand（COD） in the toilet-flushing sewage with seawater at naval seaports.The analysized procedures were as follows： initial microwave digesting for 30 min,full oxidization of chlorine ions with dichromate and disulphuric acid,addition of 0.1 g silver sulphate into the cooled solution as catalyst,and microwave digesting for another 30 min.In the process,most organic matters are fully oxidized,and then total apparent COD is measured.The COD value of the measured sample is obtained by subtracting the apparent COD of the chloride value from the total apparent COD.Results demonstrate that relative deviation is equal to or less than 10 % in the standardized solution containing Cl-≤20 000 mg / L and CODCr=100 mg / L,and RSD%≤5% in the analysis of COD in the toilet-flushing sewage with seawater at naval Ports.