In an attempt to improve the quality of the agricultural drain in Egypt for its reuse again in the irrigation, low-cost solution such as sand filter along with/without other filtration media has been used in this research. As a result of that, pilot plant of sand filter mixed with other filtration media was tested for its ability to improve the sand performance in removing the suspended solids and organic matters from agricultural drain water of the Belbeis drain (in Sharkia governorate in Egypt). Sand only, sand mixed with sponge, sand mixed with activated carbon and sand mixed with ceramic cylinders have been tested to find the best media combination and optimum mixing sand/ medium ratio and optimum infiltration rate. The work has been done on four runs. It was found that sand mixed with ceramic cylinders gave the best removal efficiency with respect to total chemical oxygen demand and chemical oxygen demand for solution which were 77, 74%, respectively, whereas sand mixed with sponge had the best removal efficiency with respect to total suspended solids which was 89%. Also, all tested media combination had effluent quality that complied with Egyptian law 48 for the year 1982 regarding the disposal of wastewater into agricultural drains (chemical oxygen demand ≤ 80 mg/l, total suspended solids ≤ 50 mg/l).

Gasoline is a complex contamination agent, which may be originated from a variety of contamination sources. Sources may include, among others, leakage of underground fuel storage tanks in gas stations and large farms. Identifying and quantifying the soil and groundwater contaminations due to leakage from the underground gasoline tanks are of primary importance in providing better regulations to protect the environment. This subject has not received much of researchers' attention in the Middle East region which is recognized by its huge oil production industry. In Al-Qassim region of Saudi Arabia, most of the existing gas stations are more than 25 years old when the region started its development era. The technology used then for the construction of the stations as well as the underground gasoline tanks are outdated and did not consider the international standard environment protection regulations. Therefore, it is expected that severe soil and/or groundwater contamination has been taking place and accumulating for years. The current research presents an attempt to assess the risks associated with soil and groundwater contamination due to gasoline leakage. Several stations within the city of Buraidah, the largest city of Al-Qassim region, have been selected for the study. A statistical study about the current status of the gas stations and the associated risks is presented. As a result of this study, a geo-environmental investigation is then conducted for two gas stations. The results of the study showed that there is an actual case of gasoline leakage which led to soil contamination with gasoline substances. This soil contamination might also threat the groundwater resources in the region due to the leaching phenomenon. The study draws the attention of the authorities to the seriousness of this problem and the importance of starting a remediation process to overcome the problem.

In an attempt to improve the quality of the agricultural drain in Egypt for its reuse again in the irrigation, low cost solution such as sand filter along with/ without other filtration media have been used in this research, As a result of that, pilot plant of sand filter mixed with other filtration media was tested for its ability to improve the sand performance in removing the suspended solids and organic matters from agricultural drain water of the Belbeis drain (in Sharkia governorate in Egypt). Only sand compared with sand with sponge and sand with Liyan Nanfang activated carbon (L.N.A.C) have been tested to find the optimum mixing sand/ medium ratio &optimum infiltration rate. The work has been done on four runs. It was found that sand mixed with sponge gave the best removal efficiency compared to that of the sand only and the sand mixed with L.N.A.C. The results presented that the concentration of CODt, CODsol and TSS was reduced from 125, 47 and 162 mg/l to 44, 34 and 28 mg/l respectively at optimum infiltration rate of 2 m³/m²/d for sand mixed with sponge.

Water scarcity and increasing environmental pressures have intensified the need for sustainable water management, including the reuse of treated wastewater. This study evaluated the continuous up-flow sand filter as a tertiary treatment process for secondary wastewater effluent. A pilot-scale filtration unit was installed downstream of the secondary treatment at Qaha Wastewater Treatment Plant (QWWTP), Egypt and operated at influent flow rates of 3.9–8.5 m³/h. Performance was assisted for removing turbidity, total suspended solids (TSS), biochemical oxygen demand (BOD₅), E. coli, total nitrogen (TN), and total phosphorus (TP), under three phases: baseline operation, variable influent quality produced by mixing secondary effluent with raw wastewater, and coagulant-assisted filtration using alum or ferric chloride. During baseline and variable influent conditions, the maximum removal efficiencies were 67.0%, 62.1% and 37.3% for turbidity, TSS and BOD₅, respectively. Alum improved the corresponding removals to 94.5%, 71.7% and 55.5%, while ferric chloride achieved 81.4%, 83.8%, and 87.5%, respectively. Overall, the results demonstrate that coagulant-assisted continuous up-flow sand filtration is a robust and practical tertiary treatment approach for upgrading secondary effluents to meet stringent wastewater reuse standards.