Evaluation of the performance and quality of wastewater treated by M’zar Plant in Agadir, Morocco

Abstract

The aim of our study is based on the characterization of the effluents treated by the M’zar plant, the monitoring of its purification performance after each treatment stage and the benefits of treated wastewater reuse in Souss-Massa region. Physico-chemical and bacteriological analyses were performed monthly from May 2019 to September 2020 on four types of water: Raw Water (RW), Settled Water (SW), Filtered Water (FW) and Purified Water treated by ultraviolet radiation (PWUV). After treatment, the pH values were close to neutrality and the concentrations of COD, BOD5, SM and bacteriological parameters were below the limits recommended by Moroccan standards, with a satisfactory abatement rate (between 97.5% and 100%), with the exception of electrical conductivity, which recorded very high values (3.7 dS/cm in PWUV) due to the salt discharged by the fish industries. In fact, the treated wastewater is rich in nitrates (289.24 mg/L in PWUV) and their reuse in agriculture can therefore contribute to making significant savings in terms of fertilization (2.08 t/day of nitrogen with a daily flow of 30,000 m3/day). Furthermore, a daily quantity of 2 to 5 tons of sludge is discharged, containing 40% to 60% of dry volatile matter, which results in the biogas production of 1275 m3/day/decanter.