الفهرس 
Literature ReviewOnly 14 pages are availabe for public view
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Abstract
Water is an indispensable necessity for all living organisms on the planet. In addition to the importance of its use in development processes such as industry and construction, it is one of the most necessary necessities for establishing life and civilization on earth. Water consists of four-fifths of the human body, human get its need of water from different drinks or drinking water directly. The daily requirement of water differs according to the seasons of the year and its health nature, and man cannot stand without water for more than three days. Therefore, it was necessary to ensure the human needs of drinking water. On an area close to 4 % of the total area of the Arab Republic of Egypt, this is about 1 million km2. These areas are concentrated around banks of Nile River for proximity to freshwater. Urban communities far away from the Nile River branches depending on groundwater, rainwater or they establish long channels separated from Nile River to reach these communities, after that they treat this raw water by establishing WTPs. Alternatively, they establish WTPs near Nile River branches then pumping the treated water through long water pipes to reach their communities. Our case study established for the second case (long treated water pipes), “South Alamein” (WTP), which is established beside El Hamam channel. Treated water pumped to Marsa Matruh city (200 Km away). The treated water pipes pass thtough several communities, starting with South Alamein city, Sidi Abdul Rahman, Dabaa, Fooka, Ras Al-Hekma and finally Garawla just before Marsa Matruh. A booster has been set up in each mentioned city to re-pump the treated water to the next city, and there is an additional chlorine-dosing unit to compensate what is consuming through that long distances.
VOCs present in drinking water because of industrial and agricultural waste discharges onto water streams or from chlorination step in the treatment process, which form a disinfection by-products (DBPs). These compounds have negative impact on the human health and environment. Disinfection By-products of Volatile Organic Compounds (DBPs-VOCs) {Chloroform (CHCl3), Bromodichloromethane (CHBrCl2), Dibromochloromethane (CHBr2Cl) and Bromoform (CHBr3)} were classified as possible human carcinogens, if they exceeded the permissible limits of Egyptian guidelines (100 μg/l) (Decree 458, 2007).
This study aimed to estimating the cumulative load of VOCs in raw water before treatment in one of the water treatment plants away from the River Nile (270 km) from Rasheed branch (South Alamein WTP.) represented by a sample from the intake as well as the VOC. The use of chlorine gas as a disinfectant in the treatment process, result in formation of carcinogenic compounds, where the chlorine reacted with dissolved natural organic matter (NOMs) in raw water. The sum of these compounds concentration should not exceed (100 µg/l) according to Egyptian guidelines. This study used granular activated carbon (GAC), which supplied ready to use directly from one of the international company (Chemviron) to assess its efficiency in the removal process as well as the rate of its consumption to reduce the concentrations of these harmful compounds to be less than the guideline value. The same study conducted on another plant near the main Nile branch in Shubra El-Kheima area, which is located in the borders adjacent to Cairo Governorate, making a comparative study showing the difference in the organic load of volatiles, either on water bodies or that produced from disinfection process.
1- A monthly samples were collected from the intakes of two slected WTPs (South Alamein WTP) and (Shubra Al-Kheima WTP) in 2016 and estimating both (VOCs) and (TOC) (48 samples).
2- A monthly samples were collected from the boosters (6 boosters) that extend between South Alamein WTP and Marsa Matrouh city (about 200 km) to estimate both VOCs and TOC (72 samples) during 2016.
3- A glass column apparatus designed (2 cm ID) packed with GAC (25 g) (height of GAC bed layer, 16 cm) ended by a fine restrictor tap helps to control the rate flow exit water and thus helps control the contact time of passed water with GAC.
4- The produced water of South Alamein WTP during August 2017 passed through a fixed bed column backed with GAC (bench-scale apparatus corresponding to South Alamein WTP) and for 40 days to estimate the maximum adsorption capacities of GAC to each four recorded parameters (CHCl3, CHBrCl2, CHBr2Cl and CHBr3). A maximum peak formation of these compounds was recorded during August (2016), in addition to TOC, which is the main precursor of the produced DBPs-VOCs.
5- Adsorption isotherms for GAC was carried out later using patch technique to estimate adsorption capacities for compounds that could not be estimated from fixed bed column experiment (CHBr2Cl and CHBr3), as they need more long time (more than 40 days in fixed bed experiment) to reach maximum adsorption capacity.
from the present study, it is clear that:
1- The plants in question are free of volatile organic matter that is likely to be present in raw water because of industrial and agricultural discharge on the freshwater streams (Nile River and its branches).
2- The study also revealed the presence of DBPs-VOCs, which formed because of the chlorination step followed in the treatment process.
3- The average values of DBPs-VOCs complies the permissible limits in respect of Shubra Al-Kheima WTP and recorded highest value in October 2016 (90.65 µg/l).
4- The average values of DBPs-VOCs were not complies the permissible limits in respect of South El Alamein WTP and recorded highest value in August 2016 (193.17 µg/l). where these values increase as we move westward through these boosters up to reach the highest value near the city of Marsa Matruh about 200 km at the Garawla booster
5- The average consumption of GAC is 581 Ton per 36 days of operation in South Alamein WTP where it produces 172,000 m3/day