稀释接种法测定五日生化需氧量的影响因素

Influencing Factors of Dilution Inoculation Method for Determination of BOD_(5)

以污水处理厂的进水和出水为研究对象,探究稀释接种法测定五日生化需氧量(BOD_(5))的影响因素(稀释水、接种液、溶解氧电极、样品稀释倍数、样品中氯含量和质控样)。结果表明,接种液和稀释水经过过滤预处理,室内温度控制在(20±1)℃,湿度控制在55%~70%,选取合适的稀释倍数,严格校准溶解氧电极,去除余氯和结合氯,5 d空白消耗值控制1.5 mg/L内,质控样测定值在180~230 mg/L,可以更大程度上提高BOD_(5)测定的准确度。

Taking the influent and effluent of wastewater treatment plant(WWTP)as the research object,the influencing factors(dilution water,inoculum water,calibration of dissolved oxygen meter,sample dilution multiple,chlorine content in sample and quality control sample)for the determination of biochemical oxygen demand after 5 days(BOD_(5))by dilution inoculation method were explored.The results showed that the inoculum solution and dilution water were filtered and pretreated,the indoor temperature was controlled at(20±1)℃,the humidity was controlled at 55%~70%,the appropriate dilution multiple was selected,the dissolved oxygen electrode was strictly calibrated to remove residual chlorine and bound chlorine,the 5 days blank consumption value was controlled within 1.5 mg/L.and the measured value of automatic control sample was 180~230 mg/L,The accuracy of BOD_(5) determination could be improved to a greater extent.