Driss Dhiba

Groundwater is essential for both water supply and environmental conservation, especially in semi-arid and desert areas. Managing groundwater resources requires a thorough understanding of groundwater characteristics and dynamics. The hydrogeochemical properties and evolution of groundwater in the Essaouira synclinal basin in northwest Morocco were studied in this research, with 105 water samples collected in 2009, 2017, 2018, and 2019. The Water Quality Index (WQI) and Irrigation Water Quality Index (IWQI) were developed to determine groundwater quality for consumption and irrigation purposes. The chemical evolution of groundwater is mainly dominated by evaporite, mineral carbonate dissolutions, and cation exchange. Contamination by nitrates is particularly severe in agricultural and tourist areas. The WQI of the 2019 campaign showed that 6.7% of groundwater samples are unsuitable for drinking; 76.7% are poor quality water; and 13.3% are very poor-quality water; while only 3.3% are drinkable. According to IWQI, the total study area has been split into 50% (good), 43.3% (bad), and 6.6% (unfit), respectively, and no excellent groundwater areas have been identified. Therefore, the water is suitable for agriculture but must be treated for drinking. The presence of evaporation and maritime intrusion and the contribution of recent precipitations to aquifer recharging were demonstrated by stable isotope content.

This experimental work aims at investigating the effects of milling; sieving; and electrostatic separation on the biochemical methane potential of two olive pomaces from traditional olive oil extraction (M) and from a three-phase system (T). Sieving proved to be efficient for increasing the soluble chemical oxygen demand in the smallest fractions of the sieve of both M (62%) and T (78%) samples. The positive fraction following electrostatic separation also enhanced chemical oxygen demand (COD) solubilisation by 94%, in comparison to sample T milled at 4 mm. Sieve fractions with a size greater than 0.9 mm contained 33% and 47% less lipids for the M and T biomasses; respectively. Dry fractionation modified sample properties as well as lipid and fiber distribution. Concomitantly; milling increased the accessibility and facilitated the release of organic matter. The energy balance was positive after knife milling and sieving; while ball milling and ultrafine milling proved to be inefficient.

Rare earth elements (REE) are present at low concentrations (hundreds of ppm) in phosphoric acid solutions produced by the leaching of phosphate ores by sulfuric acid. The strongly acidic and complexing nature of this medium, as well as the presence of metallic impurities (including iron and uranium), require the development of a particularly cost effective process for the selective recovery of REE. Compared to the classical but costly solvent extraction, liquid-solid extraction using commercial chelating ion exchange resins could be an interesting alternative. Among the different resins tested in this paper (Tulsion CH-93, Purolite S940, Amberlite IRC-747, Lewatit TP-260, Lewatit VP OC 1026, Monophos, Diphonix,) the aminophosphonic IRC-747, and aminomethylphosphonic TP-260 are the most promising. Both of them present similar performances in terms of maximum sorption capacity estimated to be 1.8 meq/g dry resin and in adsorption kinetics, which appears to be best explained by a moving boundary model controlled by particle diffusion.