This work was designed to study the effect of major drains, such as El Rahawy, on the Nile's water quality over time. The data in this study includes six years of physical and chemical variables data, starting from 2015 to 2020, covering three different water streams. The present results showed that the Rosetta branch and Khandaq sharky canal were directly affected by the agricultural drainage of the Rahway drain, with the change over time for the worse. Rayah El Nasery canal enjoyed complete independence from the negative impact of the drain while maintaining the quality at an appropriate level over time. The study predicts a decline in the water quality of the Rosetta branch in the future and recommends exerting more efforts to treat all pollutants that are discharged on the Nile and raise the efficiency of the Rahawy drain.

The Nile River is an important natural and exclusive source of fresh water in Egypt. Water samples were taken monthly from twelve sites from 2015 to 2020 in El Beheira Governorate and eighteen physicochemical parameters were measured. The results show that the Rahawy drain recorded the highest values for most of the physicochemical parameters. The HPI and MI indicators in Rahawy drain were higher (70 % & 100 %) than in other sites, especially in the summer and winter seasons. The Rahawy WQI values were classified as poor quality. The IWQI results indicate that the water quality for the Rahawy was within the "severe restriction" class, with many restrictions to be used in agriculture. The water quality of the Nile River in the south of Egypt is better than that of the north and the water quality recovery takes more time and distance.

The chitosan-coated neem flower powder was prepared and employed as an adsorbent for the removal of cationic methylene blue from an aqueous medium. The interaction of chitosan with neem flower was concluded by FTIR. The BET surface area was evaluated for the prepared NFC adsorbent. The adsorption of methylene blue dye onto chitosan-coated neem flower powder (bio-adsorbent) was carried out by varying the concentration of dye, pH, temperature and concentration of adsorbent. The adsorption capacity was evaluated by using Freundlich and Langmuir models. The adsorption data were further analysed with the help of pseudo-first and second-order kinetic models. The thermodynamic parameters were evaluated to comprehend the nature of the adsorption process.

In developing countries, it still suffers from endless problems regarding wastewater treatment and the problem of choosing the appropriate treatment system due to lack of proper technology and weak economy. This study highlights the maturity oxidation pond (stabilization) of small communities as an effective, low-cost and simple post-treatment technique for treating wastewater before discharging into an aquatic ecosystem. The Rashid plant was cited as a treatment plant in the city of Rashid-ElBeheira Governorate - Egypt as a model plant for applying this technology in treatment of wastewater. This work also includes the studying of the relationship between climatic conditions, physicochemical parameters and biomass of microorganisms to evaluate the efficiency of its performance.