Assessment of Mahmoudia Canal and Drinking Water Nitrogen Forms Following Some Corrective Actions

The Nile is the main source of drinking water in Egypt. Alexandria water Company (AWCO) depends on the surface water only as canals fed by the Nile River. AWCO has 8 water treatment plants (WTP), 6 of which are located on Mahmoudia canal. AWCO has a monthly comprehensive program to survey canals supplying water to Alexandria water treatment plants (WTP), where all parameters of Mahmoudia canal and drain discharges are measured. This study was carried out during the period from March 2008 to Jan. 2010 and the program is still implemented until now. AWCO regularly monitors the water quality in the canals in the Rosetta branch of the Nile, all the way up to the Delta Barrage near Cairo. The water quality in Mahmoudia canal is stable at a manageable level. The raw water of WTPs has faced serious problems that are affected by the increasing free ammonia and nitrite in winter season. Many corrective steps (hourly free ammonia detection, break point of chlorination and prefiltration powdered activated carbon installation) were taken to overcome these problems. The main objective of this study was to identify long term feasible solutions for the drinking water quality problems on the basis of physical and chemical water parameters. The which are corrective actions had reduced the free ammonia values by more than 75% for WTPs distributed drinking water all over the years.


INTRODUCTION
The Nile is the main source of drinking water in Egypt.Alexandria Water Company to the south.In addition, it supplies water to industry, tourism and shipping in Alexandria. (1)ainage water from irrigation is a source of increased pollutants in raw water

MATERIALS AND METHODS:
Assessment of water quality of

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AWCO) depends on surface water only as canals fed by the Nile River.Alexandria City is supplied by raw water from 2 canals (Mahmoudia canal branches from Rosetta branch and Noubaria canal branches from El-Rayah El-Behery).The Ministry of Public Works and Water Resources (MPWWR) is responsible for the management of these canals.AWCO has 8 water treatment plants (WTP), 6 of which are located on Mahmoudia canal and 2 treatment plants abstract their water from Noubaria canal.AWCO's service area covers the entire Governorate of Alexandria and part of Beheira Governorate about 100 kilometers Bull High Inst Public Health Vol.40 No.1 [2010] in addition to other sources along the Nile River.Water quality can have a major impact on both individuals and communities health.The quality of drinking-water is significant for health in both developing and developed countries worldwide.A reliable supply of clean drinking-water is essential to protect the health of individuals and communities.Both the quantity and the quality of supply are important.A secondary problem after microbiological pollution is the presence of natural or man-made contaminants such as arsenic, selenium, uranium, fluoride, nitrate or boron, which often result in crippling health effects or death due to chronic Exposure. (2)Nitrate and nitrite levels in the natural waters are important indicators of water quality.The increasing nitrate and nitrite concentrations become an important problem for public health.Hence, widespread and frequent monitoring surveys should be carried out. (3)Inorganic fertilizers and human and animal wastes (from livestock operations and septic tanks) are the primary sources of nitrate and nitrite contamination of drinking water.Nitrate released to soil as a result of human or animal activities can enter groundwater or surface water as a result of leaching or runoff.Some nitrate and nitrite exposure also originates in endogenous production of nitric oxide by many activities.Its uptake by humans is via drinking water and food.Nitrate toxicity to humans is manifested by increased levels of methemoglobin and formation of carcinogenic compounds. (4)Those compounds require advanced treatment technologies for reliable continuous removal as opposed to conventional methods such as sand filtration.The main objective of the study is to identify long term feasible solutions for the drinking water nitrogen forms problems and the relationship with water characters in the supply areas of Alexandria.These areas are supplied with drinking water which is produced at six water treatment plants.The water quality problem has been assessed by application of a comprehensive monitoring program.After assessing various data, many feasible corrective actions were applied.
Mahmoudia canal was implemented to evaluate surface water of the canal on A monthly basis according to the Standard Methods for examination of water and wastewater. (5)AWCO has a monthly comprehensive program to survey canals supplying water to Alexandria water treatment plants (WTP), where all parameters of Mahmoudia canal sampling points are measured.This study was carried out during the period from March 2008 to January 2010 and the program is still implemented until now.Sampling program points were designed to express the water quality along the canal.Sampling sites: Mahmoudia canal gets its water from the Nile River at two points.Seven sampling points were selected to represent the Mahmoudia canal before Alexandria city for 55km along and two sampling points represented the water sources for two water treatment plants (intake of Siouf WTP and intake of Manshia WTP).Table (1) and Figure (1) show the sampling sites and symbols along Mahmoudia canal and the distances from starting point.

Figure ( 2 )Figure ( 2 )Figure ( 3 )
Figure (2) the raw water is taken from along of 73 Km, where the temperature of the water is ranged between 30.7 • C (summer) to 20 • C (winter) with average 23.4,22.8 and 22.7 • C at starting point of Canal, intake of Siouf WTP and intake of Manshia WTP, respectively throughout the sampling period.Bouillot et al. (1992) worked on Parisian waters with temperatures ranging from 5 to 25°C. (6)Niquette et al. (1998) worked on colder waters (below 5°C) and showed a strong temperature impact on Biological Active Carbon filtration for the removal of both biodegradable organic carbon and ammonia.Since the main purpose of their work was not the study of ammonia removal, only few results concerning temperature effect on biological nitrification were available. (7)However, Rittmann and Snoeyink (1984) mentioned that nitrification processes have potential to

Figure ( 5 )
Figure (5): Average in mg/l of Free Ammonia (a), Nitrate (b) and Nitrite (c) for six AWCO WTPs effluent during the study period from March.2008 to Jan. 2010

Figure (1): Mahmoudia canal (Northern Egypt) and location of sampling points (Red)
nitrite, COD and BOD5 values, however the results showed a significant increase in both sampling points #1 & 2 comparing to the water coming from Khandak canal as shown in Table(2).Starting from point # 4 that recorded the net mixing of two water sources, the change in water quality was