Essam A. Mohamed

Assessment of water quality in surface waters of the Fayoum watershed, Egypt

This paper presents the first assessment study of the surface water quality in the Egyptian Fayoum Governorate (Province). A total of 42 water samples from irrigation and drainage canals as well as Lake Qarun were collected. Major ions, (semi-)metals, nutrients, salinity and microbiological parameters were examined. The results showed that the highest salinities and highest concentrations of Na+, K+, Ca2+, Mg2+,

Enhancing adsorption capacity of Egyptian diatomaceous earth by thermo-chemical purification: Methylene blue uptake

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Adsorption characteristics of Na-A zeolites synthesized from Egyptian kaolinite for manganese in aqueous solutions: Response surface modeling and optimization

SO42-, Cl− and δ18O were recorded in Lake Qarun due to up-concentration by evaporation. The highest concentrations of Al, Ba, Cr, Co, Cu, Ni, Fe and Mn were recorded in drainage waters. Tracking the fate of contaminants through sources–sink pathways helped to determine the potential sources of pollution. The highly impacted sites were located close to point sources of pollution such as sewage water treatment plants. Water used as drinking water supply has higher levels of Al and it can be harmful. High levels of microbiological contamination were recorded in irrigation and drainage waters, which therefore might cause water-borne diseases. Improper disposal of sewage or on-site sanitation tank overflowing into these waters is the main cause of microbiological contamination. Drainage and irrigation waters generally have high salinities resulting in soil salinization and degradation. Lake Qarun, a closed saline and alkaline lake, acts as the reservoir for left-over drainage waters. The results show that the lake has a self-cleaning system where most of the (semi-)metals carried by drainage waters are totally adsorbed on the lake sediments. Therefore, Lake Qarun is playing an important role in the environmental balancing in the Fayoum Governorate.

Synthesis of na-a zeolites from natural and thermally activated Egyptian kaolinite: characterization and competitive adsorption of copper ions from aqueous solutions.

Wadi El Raiyan is a great depression located southwest of Cairo in the Western Desert of Egypt. Lake Qarun, located north of the study area, is a closed basin with a high evaporation rate. The source of water in the lake is agricultural and municipal drainage from the El Faiyum province. In 1973, Wadi El Raiyan was connected with the agricultural wastewater drainage system of the Faiyum province and received water that exceeded the capacity of Lake Qarun. Two hydrogeological regimes have been established in the area: (i) higher cultivated land and (ii) lower Wadi El Raiyan depression lakes. The agricultural drainage water of the cultivated land has been collected in one main drain (El Wadi Drain) and directed toward the Wadi El Raiyan depression, forming two lakes at different elevations (upper and lower). In the summer of 2012, the major chemical components were studied using data from 36 stations distributed over both hydrogeological regimes in addition to one water sample collected from Bahr Youssef, the main source of freshwater for the Faiyum province. Chemical analyses were made collaboratively. The major ion geochemical evolution of the drainage water recharging the El Raiyan depression was examined. Geochemically, the Bahr Youssef sample is considered the starting point in the geochemical evolution of the studied surface water. In the cultivated area, major-ion chemistry is generally influenced by chemical weathering of rocks and minerals that are associated with anthropogenic inputs, as well as diffuse urban and/or agricultural drainage. In the depression lakes, the water chemistry generally exhibits an evaporation-dependent evolutionary trend that is further modified by cation exchange and precipitation of carbonate minerals.

Geochemical modeling of evaporation process in Lake Qarun, Egypt

In the current study, calcination and thermo-chemical methods were applied in treatment of the processed diatomite fraction (<45 μm), which containing nearly 82.6 wt.% of the raw Egyptian diatomaceous earth. The untreated and modified diatomite fractions were characterized by optical microscopy (OM), X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Thermo-chemical purification produced the highest concentration of diatom frustules (>92% SiO2) without blocking impurities and created SiOSi active sites. These fractions were tested for Methylene blue (MB) adsorption at different pH solutions (2.0-10.0). The purified diatomite via thermo-chemical treatment (PD) gave the greatest adsorption capacity for MB compared to the untreated (UD) and calcinated (CUD) diatomite fractions. Effects of experimental parameters such as MB concentration (60-200 mg L-1), contact time (5-480 min), adsorbent mass (50-250 mg) and temperature (30-55 °C) on MB uptake were investigated. Linear and non-linear forms of Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models indicated that Langmuir model with a maximum adsorption capacity (qmax=105.03mgg-1) fitted well the adsorption data. The chemical nature of MB uptake was revealed by the values of mean free energy E=8.655kJ/moland correlation coefficient of the pseudo-second-order model (R2=0.9997). The calculated thermodynamic parameters (ΔH0, ΔG0 and ΔS0) indicated that the removal of MB is spontaneous and endothermic.

Hydrogeochemical Processes Controlling the Water Chemistry of a Closed Saline Lake Located in Sahara Desert: Lake Qarun, Egypt

Wadi El Raiyan depression represents a discharge area of excess wastewater from the Faiyum province. It comprises two lakes: the upper lake connects the lower one through a channel. The intensive agriculture in the area hazardously affects both lakes. To assess the status of these lakes, this work studies the change detection using image classification and post-classification comparison, physicochemical parameters, concentration of trace elements, and microbiological contents. The classified images indicate a maintained constant area of the upper lake from 1990 to 2012 and decreased by 1.6% in 2014. The lower lake area increased by 4.8% between 1990 and 2001, then decreased till 2014 and increased again by 8.4% in 2015. The change detection concluded that the lake could be disappeared by 2019 if the exploitation of water from the upper lake continues, or the lake could be rebounded if the government planned to increase the recharge. The factor analysis implies that the total Fe, Mn, Ni, Ba, and As are controlled by pH–Eh relationship, Cu by TDS, Pb by temperature, while Cd is attributed to anthropogenic factor. The upper and lower lake samples exhibit biological oxygen demand (BOD) and chemical oxygen demand (COD) values lower than fish farm samples. The high BOD and COD values were coupled by high nitrate contents in the studied water samples. The cultivated land drains and the fish farms samples have total coliform (TC) and fecal coliform (FC) higher than the samples collected from the upper lake.