Geochemical and Isotopic Study of a Coastal Phreatic Aquifer from the NE of Tunisia: Guenniche Basin

International audienceThe geochemistry and isotopic composition (18O, 2H) of groundwater from the alluvial phreatic aquifer in the Wady Guenniche basin (NE of Tunisia), were investigated in order to reveal the origin of the water salinity. The major geochemical processes in the aquifer are evaporite mineral dissolution and mineral exchange with clays. The salinization of groundwater would be a limiting factor in their use for irrigation. The stable isotopic composition of water indicates a groundwater recharge in current climate condition and the point closest to the sea indicates the possible beginning of a seawater intrusion as a result of the intensive exploitation of resources. The tritium data confirm a recent recharge younger than 1950

Hydrogeochemical characterization of the Menzel Bourguiba aquifer system (north-eastern Tunisia)

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Naturel Tracer and Isotopic Approach to Describe Groundwater Behaviour: An Example of the Mateur Plain (North-Eastern Tunisia)

International audiencePhysical and chemical data, have been taken from the whole of Mateur plain (NE Tunisie) (Fig. 1a). In Mateur region, most waters come from phreatic aquifer and deep aquifers. These aquifers show indications of advanced overexploitation, revealed by decreasing piezometric surfaces and degradation in water quality. The total dissolved solids (TDS) were measured in September–October 2015 at 72 water points drilled in the phreatic aquifer and deep aquifers. The upstream zone of Mateur shows good chemical quality water, with a TDS varying from 0.7 to 1 g/l. However, highly mineralized waters (over 1.5 g/l) were found in the middle-Mateur plain and downstream zone

Caractérisation hydrogéochimique du sytème aquifère de Mateur (NE Tunisie)

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Assessment of the toxicity and the fertilizing power from application of gamma irradiated anaerobic sludge as fertilizer: Effect on Vicia faba growth

With increasing sludge produced every day by wastewater treatment plants, new methodologies have been developed to reduce sludge or to valorize them at lower cost and energy. Among these methodologies, agricultural manuring is of great interest as sludge could complement or replace chemical fertilizers. However, sludge pretreatment was necessary prior to its use in order to eliminate the degradable organic contaminants, heavy metals and diverse pathogenic microorganisms. In this study we performed γ-irradiation of anaerobic sludge coming from wastewater treatment plants at different doses (0.5, 1.5, 2.5, 3.5 and 4.5 kGy), followed by anaerobic digestion. We then used them in addition to soil for Vicia faba cultures. Heavy metal concentrations, toxicological evaluations, and the number of cultivable pathogenic bacteria were also investigated in irradiated and non-irradiated sludge samples to determine the effect of γ-irradiation on toxicity and pathogens present in the sludge. Results show that 4.5 kGy is the optimal dose, and γ-irradiation pretreatment of anaerobic sludge added to soil (2 mL/30 g) has significantly improved Vicia faba growth. Furthermore, by eliminating pathogens and by degrading chemical pollutants, γ-irradiation of anaerobic sludge provides promising insights for re-using sludge as a safe fertilizer