2. Materials and methods
2.1. Analytical methods
Measured the pH by (PHS-3E) and EC by (DDSJ-308A);
For measuring the organic material MO, the Anne method was used; according to AFNOR standard (X 31-109)
[10].
Measuring the rate of limestone is made using the BERNARD calcimeter [10].
The particle size curve of N'goussa washed sand has been prepared by passage through a series of sieves
according to AFNOR standard (NF 1996) modified (lack of 0.400 and 0.250 screen).
determined the chemical oxygen demand (COD) by the colorimetric method [10].
2.2. Effluent qualities
The conductivity of a wastewater in highly variable from one region to another depending mainly on
natural mineralization of drinking water[5]. From this, the waste water samples have been systematically
compared to the composition of domestic ones which were taken as a reference. Therefore, different concentrated
solution made of mixtures of chemicals and alimentary products have been prepared[6]. This latter was used as a
reference for the five other synthetic wastewaters when its EC≈0.87 mS/cm (0.036 g/l of CaCl2.2H2O). We added
CaCl2.2H2O salt between 0.036 g/L and 2 g/L to increase the electrical conductivity of the wastewater between
1.5 and 3.5 mS/cm with a step of 0.5 mS/cm. The resulting synthetic wastewaters was dried overnight and
characterized by (see table 1).