chemical oxygen demand (COD)的用法和样例：
例句
- Therefore, COD is a conditional indicator, and strict operation procedure must be followed.
因此，化学需氧量亦是一个条件性的指标，必须严格按操作步骤进行。 - The results showed that magnesium hydroxide had good effect for decoloring and suspended substance removal,meanwhile,removal rate of chemical oxygen demand was also quite high.
研究结果表明，氢氧化镁在印染废水的处理过程中，具有良好的脱色效果和悬浮物的去除效果，对化学需氧量的去除率也相当高。
