The water of the river N’djili is used for several facts. Indeed, due to a lack of the servicing in drinking water in several districts of the city of Kinshasa, several residents use the water of this river as water of bathing, of cooking, of washing of linens, of drink, of watering of the gardens and washing of the gardening products (vegetables and tubers), etc. There is place to underline that biggest user of the water of the river N’djili is the REGIDESO that extracts every day a nominal volume equivalent to ±550.000 m3 of raw water in order to purify it to go against at least ¾ of the population of Kinshasa in drinking water. Yet several human activities susceptible to damage the quality of the water of this river are identified in its perimeters very brought closer. The danger is that in case of pollution of the river N’djili, several score of thousands of Kinshasa’s population should be exposed directly to water illnesses with risk of the epidemiological propagation, while the REGIDESO will be obliging to use big quantities of reagents to succeed in purifying this water polluted without forgetting the risk of resistance of some badly known pollutants. It will be able to be obliged however to resort to a lot of more refined techniques and expensive. A resource of as big importance had to absolutely be protected while the activities capable to harm to its good working should be regulated restricted either.

The environment (middle) of three important sites of catchment of water of the REGIDESO in Kinshasa notably the rivers N’djili and Lukunga and the Congo stream is in particular vulnerable following the failure to respect of the environmental hygiene by the riparian populations of these three sites and of all kinois in general. This survey proposes to verify the degree of water pollution treated by the REGIDESO and the efficiency of the treatment techniques applied by this one to purify water. For that to make, 3 samples by site of the raw water and three of water treated have been appropriated and have been analyzed in order to determine the physic-chemical parameters (MO, MES, Turbudité, pH, T°, SD, Co, NO-3, PO 4, FeT, Pb, OD, DBO5 and DCO) and bacteriological (fecal coliforms, fecal streptococci and Escherichia Colis) for the raw water, while for the treated water, it has about of the analysis of the data base of the laboratory of the REGIDESO. The gotten results show that the dismissals descended of the human activities upstream of the sources of catchment have negative impacts on water to treat and that some parameters as the total iron, the DCO and the MY don't answer the norms of the drinking water. Otherwise, the meticulous exam on one period of one year of the archives of the laboratory of the REGIDESO indicates some temporary, daily or periodic failings as for the bacteriology.

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