How do you clean water and return it to the environment?

Each of us consumes an average of 150 litres of water per day. Once it has been discharged into the sewer system, it is collected and treated, before returning to the natural environment. This invisible action is particularly essential. It is one of our lines of business.

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Steps

Step 1 - We collect wastewater
Domestic wastewater, rainwater and some industrial wastewaters are collected by a drainage network that takes them via main sewers to a wastewater treatment plant.

Step 2 - We take any solid waste out of the water
What do we mean by solid waste? Branches, leaves, various plastics, cans, etc.

Step 3 - We remove the grease and oils
The water is cleansed of these contents that float to the surface, and of sand and grit that sink to the bottom of the tanks. They are sucked up and disposed of.

Step 4 - We perform a biological treatment
In an aerated tank, we grow microbes (bacteria) that feed on the pollutants dissolved in the water. This activated sludge process reproduces the same self-purifying system that exists in the natural world.

Step 5 - We separate the purified water from the sludge
This last step is carried out with a clarifier.

Step 6 - We make use of the sludge
It will be reprocessed for use in farming (fertilizer or compost, for example).

Step 7 - We return the water to the natural environment
The water doesn’t have any pollutants in it anymore. It can therefore be returned to nature.

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