2. Calculate how much oxygen is needed to completely oxidize a bag of washing powder.
3, given a sewage index (user-defined, for example, cod 1000 is
It is regarded as sewage, or the discharge index of a sewage treatment plant in a certain place is sewage index, that is, a unit sewage oxygen demand index is set)
4. Total calculated oxygen demand/unit sewage oxygen demand = polluted water.
When writing a paper, it is not clear how much water a bag of washing powder can pollute. After all, no one knows what the concentration will be after entering the water. But you can check the annual output of washing powder. After all, these products eventually enter nature as pollution sources. You can say that tens of thousands of tons of washing powder pollute our limited water resources every year.