Question: Where does the dirty water come from

Amy Heather Fitzpatrick answered on 21 Nov 2019:

So dirty water comes from lots of different sources. So imagine a big mountain, on the top of the mountain the water is very clean but as it goes down the mountain the river might meet animals, factories, people swimming, other buildings and maybe waste water pipes. SO the animals might poop near the water or sometimes the medicine they get might get into the river. Then later, this contaminated water will pass by a dairy factory, that pumps out gone off milk. The bacteria from the river and the animal poop in the river, might like the milk or not like the milk. If they like the milk they might start fermenting it or digesting it in different ways, and produce nitrogen or ammonia or carbon dioxide. Or the increased nitrogen from the milk can encourage the algae/phytoplankton to grow really fast. They could turn the river green or red. Now the river meets other rivers and people might throw their plastic rubbish in it after having a picnic. Someday it might rain a lot a waste water pipe, might be too full of sewage and rain water and burst. This sewage can also end up in the river. So by the time the water reaches the water treatment plant, it can become dirty in many different ways. Does this make sense?