Water can be polluted either by human action or by the after-effects of industrial and economic development. However, in order to avoid water pollution as much as possible, users must take several precautions both on land and in the aquatic environment. For this, it is recommended to opt for less polluting activities, to reduce the discharge of the substances used and to take care of the polluting flows in the catchment area.

Purifying water before discharging it directly into nature

In order to avoid water pollution, it must be purified before being discharged into the natural environment. Wastewater must be strictly treated; that is to say, a purification treatment is strongly recommended in order to eliminate the different polluting substances it contains. After purification, the water is not potable, but the quantities of polluting residues must be low, or even almost non-existent, after treatment. The self-purification of the environment will then take over the purification process. The rather frequent case is that of a river. In sanitation areas: a place to purify wastewater before it is discharged into the aquatic environment, several standards and steps must be followed before the water is discharged into the environment. Likewise for the dwellings located in these areas, they are subject to rules and compliance controls for the sanitary installations of the dwellings.

Reducing or prohibiting the use of hazardous substances

Some substances hazardous to health are mostly released into the natural environment and always end up in water. They are not biodegradable, but are highly carcinogenic. To avoid water pollution, it is therefore preferable to ban or reduce the production of these products. It is the insecticides, chloracetone, phosphates contained in domestic detergents that reduce the proliferation of algae in running water. Thus, all new chemical substances must be evaluated in order to know their dangers. If such a product presents any risk, its use must be subject to authorisation and the most dangerous must be restricted.

Remediation of the aquatic environment

It is the most effective, but most difficult and expensive solution to avoid water pollution. All polluting substances discharged into nature are discharged into the aquatic environment and therefore they can contaminate several areas. The principle of water pollution control is based on the extraction of sediments contaminated by the polluting substances. Artificial canals and canalised rivers can also be remediated. The fact that the pollutants are found in living aquatic organisms makes them more resistant and difficult to degrade, hence the name persistent organic pollutants, which currently generate harmful effects by causing hydrological alterations.