IMPACT OF ORGANIC POLLUTANTS FROM POINT SOURCES ON NILE WATER QUALITY

Abstract

Since the construction of the Aswan High Dam, the quality of the Nile River water in Egypt has become primarily dependent on the water quality and ecosystem characteristics of the reservoir (Lake Nasser), and less dependent on the water quality of the upper reaches of the Nile. Water released from Lake Nasser generally exhibits the same seasonal variation and the same overall characteristics from one year to another. Downstream changes in the Nile River water quality are primarily due to : (a) different hydrodynamic regimes regulated by the Nile barrages, (b) agricultural return flows and (c) domestic and industrial waste discharges, in addition to oil and wastes discharged from passengers and river boats. These changes are more pronounced as the river flows through the density populated urban and industrial centers of Cairo and the Delta region. Tile mai11 objective of this study was to assess the impact of organic wastewater discharge on the water quality of the Nile River .The investigation was limited to the Nile River basin from Aswan to El-Kanater, the length of which is 953 Km. The basin was divided into four reaches. The first reach extends from the outlet of the Aswan Dam (zero Km) to 167 Km, the second from 167 Km to 359 Km, the third from 359 Km to 544 Km and the fourth from 544 Km to 953 Km. Tile results of the surveys, which have been carried out during the period from 1991 to 1999, indicated the presence of 32 industries and 73 drains. Physico-chemical characteristics of some parameters, which represent the impact of pollution with organic compounds on the water quality, were selected. These parameters were DO, BOD, COD surfactant, ammonia and oil & grease.The loads of pollution contributed by point sources were calculated. The present study showed that hydrological conditions in the Nile River from Aswan to El-Kanater El-Khiria, have varied significantly during the past decade.