This study detailed the effect hydraulic retention time on characteristics of the El-Oued aerated lagoons wastewater treatment plants (WWTPs), located in Southern East Algeria. The plant performance was evaluated through descriptive and statistical analysis of quantity and quality data of both raw wastewaters and treated effluent over a period of three years (2013 -2015). Therefore, the downstream values of BOD5, COD and TSS, are enough to achieve a final effluent that would meet the Algerian standards limit. The retention time is a function of the percent removal of organic load. The retention time may vary from 12 to 20 days as the optimum operating conditions the removal efficiencies 86.5% of BOD5, 78% of COD and TSS 85%. Goodness of the model fit to the data was also evaluated through the relationship between the residuals and the model predicted values of BOD5r, CODr and TSSr. The advantage of this model is that it would allow a better process control.

The Aim of this Study was to Determine the Physicochemical Composition of Water Intended for Human Consumption in Several Regions of El-Oued - Algeria. Excess Minerals in Drinking Water, Including Magnesium, Calcium, Sulfates, Chloride and Fluorides Play a Fundamental Role in the Prevention of Urinary Calculi, which are Formed Mainly from Calcium Oxalate. the Results Revealed that Wholes Water Samples are Analyzed Magnesium ([Mg 2+] > 50 Mg/L). the Rate of Sulfate Ions Average 638 Mg/l, Exceeding the Maximum Allowable Concentration (MAC) Recommended by WHO ([SO42ˉ] > 250 Mg / L). in Addition, 85% had Excess Fluoride [Fˉ] > 0.85 Mg/L, and 100% are Calcium, the Rate of Ca2+ is Greater than 150 Mg/L.

The aim of this study was to determine the physicochemical composition of water intended for human consumption in several regions of El-Oued -Algeria. Excess minerals in drinking water, including magnesium, calcium, sulfates, chloride and fluorides play a fundamental role in the prevention of urinary calculi, which are formed mainly from calcium oxalate. The results revealed that wholes water samples are analyzed magnesium ([Mg 2+ ] > 50 mg / L). The rate of sulfate ions average 638 mg / l, exceeding the maximum allowable concentration (MAC) recommended by WHO ( [SO 4 2ˉ] > 250 mg / L). In addition, 85 % had excess fluoride [Fˉ] > 0.85 mg / L, and 100 % are calcium, the rate of Ca 2+ is greater than 150 mg / L.

<p>- Investigation of El-Oued natural clay at Saharan zone located Southwest Algerian.</p> <p>- Elaboration and characterization mineralogical and physicochemical</p> <p>- XRD, FTIR, SEM, XRD, BET, and CEC </p> <p>- - The studied clay is mesoporous and it has an isotherm type IV.</p> <p>- - The Clay are rich in illite (62%) and kaolinite (27%), with less percentage of quartz (11.1%).</p> <p>- Algerian natural clays can efficiently for the removal from the wastewater.</p>