See scheme about the water pollution
The first one, the house pollution is the most important. It results from the daily use of the water in private homes. We know that the daily use of water represents approximately 140 litres a day and per capita and that this water is eventually almost totally rejected. Domestic waste water includes waters said "housewives", such as waste water from cooking or bathroom and waters said "gates" (toilet). We find in "domestic" waters, fats, soaps and cleaners.
To this are added the waste waters thrown back by the collective installations, such as hospitals, businesses, school buildings or hotels. Domestic and collective waste water represents approximately 400 litres a day and per capita.
In traditional domestic waters are added rain waters that can engender a strong environmental pollution especially after a long period of drought. Water-treatment plants are overwhelmed and untreated waters are thus poured in the natural environment. Furthermore, the washing of roofs, pavements and streets increases the risks of urban pollutions of natural resources.
There are several types of industrial pollutions according to the use which is made of the water during industrial processes. So, the industries can cause:
oorganic pollutions (food-processing industries, paper mills, slaughterhouses)
ochemical pollutions (tanneries, textile factories)
ohydrocarbons pollution (petroleum industries, transport)
ophysical pollutions (radioactivity, nuclear power stations, suspension materials of mines or steel industry).
It is true that on the banks of the river the Charente, we do not find all these types of industrial pollutions; indeed, there is no nuclear power station let alone petroleum industries. Nevertheless, there are industrial paper-makers, in the region of Angoulême, food-processing industries and textile industry; these types of industries are considered as throwing back particularly polluting materials for the water. The present industries on the river the Charente are especially concentrated upstream of the city of Cognac and characterized by food-processing industries and by distilleries.
It is also necessary to note that more than 8 700 tons of toxic waste are generated each year on the river the Charente. If no solution is implemented then this waste may bring important quantities of metal and organic micropollutants in the natural environment.
The agriculture often constitutes the first cause of the diffuse pollutions of water resources. It is the case on the river Charente that is characterized by important pollutions of agricultural origin. When we speak about agricultural pollutions, we speak at the same moment about pollutions stemming from cultures and about pollutions stemming from breeding. The agricultural activity is characterized by important wastes of nitrogen, nitrites and nitrates, which we find in strong concentrations in fertilizers but also in liquid manures and manures of breeding. The agriculture within the region is very varied, with an important place given to the cultures of corn, colza and wine in the region of Cognac.
The East of the river the Charente constituted by meadows is dedicated to the breeding of cattle (approximately 15 % of the territory)
In the North-North/western part, it is the big cultures which dominate (approximately 42 % of the territory)
In the South-South/western, an important part is devoted to the culture of the vine around Cognac and around Jonzac (approximately 40 % of the territory)
In the far North western part, we find market garden sectors, bovine breeding, polyculture but also big cultures (approximately 3 % of the territory)
The culture of wine is the one that generates most pollution because it uses a lot of pesticides. These "phytosanitary products" consist of a multitude of very harmful substances for the natural environment of streams.
To mitigate these types of pollution, we have built numerous water-treatment plants in our cities and villages. These equipments of collection and waste water treatment are meant to reduce the impact of the domestic, agricultural and industrial pollutions to insure the conservation of our water resources and our environment. Nevertheless, these are not enough equipped to destroy the nitrogen (that we find in waters "gates") and phosphates (that we find in the washing powders) present in waste water. Numerous pollutants are thus poured in the natural environment and are going to be used as food by certain micro-organisms that we call more collectively seaweeds. These are going to propagate and to consume all the oxygen necessary for the survival of the native fauna which is afterward going to disappear. It is what we call the phenomenon of eutrophication.
