Treatment Performance of an Autonomous Gray Water Treatment System (SAUTEG) with the Macrophytes Thalia geniculata

The treatment of domestic wastewater and the improvement of our living environment is a matter of concern. Less costly methods are to be promoted because of the low financial power of the developing countries. In order to satisfy this requirement, here we have proposed an autonomous system for gray water treatment (SAUTEG) using the macrophytes Thalia geniculata plants. This system is composed of 75 plants/m ² and purifying capacity EH equal to 8.7 x10 -3 equivalent-inhabitant. Using this system, gray water (catch water: EGo and collectors of wastewater: ECo) were collected and processed (EGT and ECT) and physicochemical parameters of the gray water were determined according to the French standard. There was a significant reduction in organic pollution at the level of EGT and ECT respectively (BOD 5 : 93.49% - 99.04%, COD: 94.40% - 98.25%, MES: 99.99% - 99,98%), organoleptic parameters (color: 86.50% - 84.63%, Turb: 94.13% - 88.61%), trace metallic elements (Pb: 24.52% - 87.02%, Cd: 11.84% - 21.42%). There was also nutrients removal (NO 3 - : 96.49% -19.04%, NTK: 94.94% - 100% and PO 4 3- : 14.69% - 55.02%). The treated water was less turbid and lighter. There was a good performance of the system regarding biological parameters (E. coli: 100%; Enterococci: 100% and thermo-tolerant Coli: 99.99%). The values were close to those reported in the literature and some meet the standards of domestic wastewater treatment. Comparative study of the results revealed that the SAUTEG purified the waters from the collector better than the gray water. Thalia geniculata plants, in the system played an important role in the reduction of nitrates and lead in domestic wastewater. This system would therefore contribute to the improvement of the environment. We are looking forward to extending this study to other pollutants and to evaluating the saturation time of the system.