MODELING OF WASTEWATERS TREATMENT PLANT FOR THE CITY OUAZZANE

Morocco has a mobilizable water heritage of 21 billion m3 including 16 billion m3 of surface water and 5 billion m3 of groundwater. Unfortunately, due to the exponential population growth and economic and social development, these water resources can't meet the growing demand of the agriculture, industry and drinking water sectorsIn addition, more than 546 million m3 of raw wastewater is discharged annually into the receiving environment and only a tiny proportion is reused in the irrigation of about 7000 ha. Most of the wastewater discharged is responsible for the pollution of the environment.To seek new water resources while curbing pollution, Morocco has undertaken a gigantic project of treatment of its wastewater. The city of Ouazzane, like other urban agglomerations, must choose an adequate system for the purification of its wastewater discharges.The present work proposes the design and sizing of a natural lagoon WWTP based on demographic data, pollutant load, wastewater flow and availability of land for the city of Ouazzane.The project proposes a pretreatment using vertical manual grids of 36 bars of 10 mm diameter spaced 12 mm apart. Sand / grease separator of 5.6x1.8 m. Primary treatment with a circular primary clarifier 16 m in diameter, 3 m deep and 602.88 m3 in volume. Four anaerobic basins with a depth of 4 m, a volume of 8204 m3 and a size of 58.02 x 35.35 m each. Also, four Optionals basins 2 m deep, 41008 m3 deep and 107 x 192 m in size each. Finally, four ripening basins of 1 m depth and 6 400 m3 of volume each.