The objective of this study is to evaluate the degree of pollution of wastewater from the city of Nouakchott, Mauritania, including the entry of the wastewater treatment plant (WWTP) with a physic-chemical characterization of the raw water. The average values of the pollution load in terms of organic matter BOD5, COD, nitrogen material of ammonium NH4 +, suspended matter and ortho-phosphate PO43- are 538.71 mg / l, respectively, 1806.76 mg / l 110.8 mg / l, 658.45 mg / l and 111.47 mg / l.
The pH and temperature were determined by a pH meter type HANNA Instruments HI 9622. The conductivity was measured by a type of portable conductivity meter Hanna, COD by a spectrophotometer and a model 45600 COD reactor and the BOD5 a OxiTop and ammonium ions, orthophosphates are analyzed by colorimetric methods using a UV spectrophotometer Visible type 722 S Beijing.
The results achieved show that these raw sewage at the entrance to the WWTP are too loaded pollutants exceeding the standards. A principal component analysis (PCA) was applied showing an inertia of 69.61% of F1 and F2 axes exploring the most polluted month.
Due to the ancient of the treatment plant in the city of Nouakchott in Mauritania and the increasing rate of the population of this city so far, it requires renewal and reconstruction of a WWTP that meets the requirements international.