1. Our experiment : discovery of a wastewater treatment plant
1.
The water gets dirty when we wash,
when we go to the toilet, ...
In a pot with water, we add waste (toilet paper, orange
juice, mayonnaise, oil, detergent, dirt, ...).
2.
In the sewers, all wastes are mixed.
With a spoon, water is mixed with the waste.
3.
The water passes through the screening.
We remove most of the waste with a sieve. The water
is still not clean.
4.
The water is then oiled and sanded off.
Wait one hour !
Oils come to the surface.
The sand falls to the bottom of the pot.
5.
The water between the oil and the sand is pumped.
6.
The water obtained is not yet good to go to the river.
In a sewage treatment plant, bacteria feeds the
wastes that are still in the water.