Lake Mellah close to the Mediterranean Sea in north-eastern Algeria belongs to valuable ornithological sites with nu-merous, often migratory, birds. To achieve the research goal, seventeen (17) sampling points were sampled based on the urbanization of the watershed. Water samples were taken at different wadis levels (upstream and downstream of settle-ments), as well as at the wastewater treatment plant and in Lake Mellah based on four measurement campaigns conducted at one frequency seasonal (high water, low water) during the year (2011/2012). Biological parameters (coliform faecal bac-teria, streptococci) were analysed in water of the lake and its affluents in the laboratory of the Department of Health and Population, El Taref by the most probable number (MPN) technique of the Mac Grady table taken from various points. Ob-tained results were processed by the use of Bourgeois ratio (coliform faecal bacteria: streptococci) to indicate the origin offaecal contamination of waters and to establish maps of the spatio-temporal evolution of this ratio by the software Surfer 9. This way we obtained information of contamination of human origin during the dry season coming from domestic waste waters. In winter the ratio showed animal prevalence of contamination coming primarily from Animal Park in El Kala.

This study is the evaluation of the coagulation efficiency of the aluminum sulfate on the removal of catechol and pyrogallol. The study has focused on the impact of inorganic components of hardness Algerian waters. Jar-test trials were conducted on the two phenolic compounds dissolved in distilled water only, which was later enriched with minerals. Several reaction parameters varied, including the effect of pH and the influence of the salt content, and this approach yielded a better understanding of interaction between phenolic compounds and calcium/magnesium salts. The results indicate that the process efficiency depends on the number and position of OH in molecules. The main mechanisms would be either a physical adsorption, an exchange of ligand, or complexation on the floc surface of aluminum hydroxide. Moreover, the addition of inorganic salts appears to improve removal efficiency of tested phenolic compounds and have an effect on the optimal pH range for coagulation.