NEEDED INNOVATIVE URBAN WATER MANGEMENT FOR DEVELOPING COUNTRIES, CASE OF EGYPT Abdelwahab M. Amer Irrigation and Hydraulics Department,, Faculty of Engineering, Cairo University, Giza, Egypt. E-mail: amamer8@yahoo.com ABSTRACT Water has been a critical component for development in Egypt. As population increases demand on the limited water supply increases. To meet the competing demands, more attention is given to non-conventional water resources. As a result, and following a general increase in wastewater treatment, wastewater reclamation and reuse is expected to increase sharply over the next few decades and becomes an important aspect of integrated water resources management. Important projects are being developed and wastewater reclamation and reuse facilities have been built. This paper presents the status of wastewater reclamation and reuse in Egypt and highlights the existing reuse standards. Treated effluents in general do not meet the standards for disposal to watercourses. Positive and negative effects of the use of reclaimed water for agricultural production are discussed. It is needed to establish guidelines on wastewater reclamation and reuse. Innovative demand management and supply enhancement measures have to be adapted, among which low level of treatment and dual distribution systems. KEYWORDS Reclaimed wastewater; reuse criteria; water management. WATER RESOURCES IN EGYPT Egypt is a very arid country. The Nile river is almost the exclusive source of surface water. It provides Egypt with 55.5 billion m3/year. The total dissolved solids (TDS) for the Nile ranges from 175 mg/l at Aswan to 210 mg/l at the Delta barrages. Deterioration in water quality occurs in northward direction due to urban water effluent and agricultural drainage as well as decreasing flow. Canals have water quality similar to that at the points of diversion from the Nile. Drains between Aswan and Cairo receive run-off from agricultural lands with satisfactory water quality. Drains in the Delta have extremely variable quality. Drains in the Delta have extremely variable quality. Some of it receive municipal and industrial wastewater in addition to agricultural return flow. Groundwater in Egypt can be divided into two categories. The first comprises the Nile valley and delta aquifer system with renewable water of Nile origin. The second is the nonrenewable deep groundwater in the western desert. Shallow small aquifers in the coastal areas along the Mediterranean sea receive water from the limited rainfall. Nontraditional water resources are agricultural drainage water, reclaimed water, and limited amounts from desalination. POPULATION GROWTH AND PER CAPITA WATER AVAILABILITY Egypt is approaching the stationary growth stage characterized by slow decrease of annual crude birth rate which reached about 2.7% in 1996 against rapid decline of crude death rate which has dropped sharply to the minimum of 0.62% in the same year. The settlement pattern of population whether in rural or urban areas is another important aspect of population growth. The percentage of rural population ranged between 55.5% and 56.5% during the last three decades. Water needs for human uses in urban are about 1.5 times that of rural areas. Considering total renewable water resources, per capita quota was 1893 m3 in year 1960, 967 m3 in year 2000 and estimated to be 673 m3 in year 2025 (Fig. 1). Population Fig. 1: Changes in per capita quota of water and population in Egypt, 1897-2025 (Adopted from Khalifa and Abdelmonem, 1997) URBANIZATION EXPANSIONS In the last three decades the map of Egypt has been changing considerably. The overpopulated cities are no more capable to cope with the increasing population. Many new cities, towns and settling communities in different parts of the country are under construction and expanding rapidly. Numerous resorts have been constructed along the Mediterranean sea coast, Red sea coast, and Sinai. Moreover, random urbanization steadily expands at the fringes of big cities. The newly urbanized areas impose additional stress on the management aspects of urban water. Nontraditional techniques and ideas have to be applied to avoid the cronical problems of old cities. WASTEWATER TREATMENT Only the biggest cities in Egypt (about 60 cities) have public sewerage systems. Most of the networks are overloaded and in poor condition. Sewerage and sanitation facilities were lagging behind water supply. Recently, the Government of Egypt (GOE) has launched an ambitious program for constructing new wastewater collection and treatment systems allover the country. Work undertaken over the last two decades has involved the design of an extensive wastewater collection system and six major wastewater treatment plants to serve the population in Greater Cairo. Five of these treatment plants are in operation. The wastewater treatment technologies employed in these plants are: activated sludge; aerated lagoons; and wastewater stabilization ponds. They provide secondary treatment to the domestic and industrial wastewater of about 3,000,000 m3/day generated by a population of 16 million persons. The daily flow is expected to reach 4,000,000 m3/day in 2025. Considering the predicted increase in population, urbanization and consequently water consumption, then the reuse of treated effluents in Egypt is very crucial. WATER SUPPLY ENHANCEMENT Innovative supply enhancement measures include new water supplies from new facilities, reclamation and desalination plants, water transfers, improving existing system operations, and increases use of groundwater. Reused water can be added to the supply system as either a new source of water supply or for pollution control (Wilchfort and Lund, 1997). Reused water has been used in different parts of the world for agricultural and landscaping irrigation, industrial processes and cooling towers, toilet flushing, groundwater recharge and direct consumptive use (Marecos et al., 1996). Asano and Madancy (1984) considered that water reuse is more feasible and cost-effective for nonpotable purposes. In evaluating the cost of reuse as a water supply source, the cost of treatment, the conveyance system, and operation and maintenance should be considered (Asano and Mills, 1990). In Egypt reclaimed water has been used since 1915. An area of about 10,000 acres at AlGabal Al-Asfer, northeast of Cairo, is irrigated with wastewater which receives only primary treatment (Abdel El-Naim, 1988). During the period 1986-1992, about 71,000 acres were reclaimed and irrigated by greater Cairo sewage effluents mixed at 1:1 with clean freshwater. Studies were carried out to irrigate about 80,000 acres in the western delta region at El Bustan using sewage effluents from Alexandria. There are considerable future plans for irrigation using reclaimed water (Abu-Zeid, 1993). Future urban wastewater projects include facilities for advanced treatment, which is still lacking in Egypt. Table 1 presents the estimated wastewater treatment capacity in Egypt (Abou-Rayan and Djebedjian, 2000). Table1: Estimated Wastewater Treatment Capacity (million m3/year) Zone 1997 2025 Greater Cairo Alexandria Delta Upper Egypt Other Urban Areas 1278 237 949 438 256 2219 412 1648 761 449 Total 3158 5489 Okun (1997) considered that dual distribution systems provide an additional economical water source and reduce the cost of wastewater disposal. Such systems are in use worldwide; one system is used for drinking water and another for reclaimed water. They permit more appropriate use of limited high-quality water sources while exposing the public to little additional risk. Dual systems are particularly appropriate for urban developments now being planned, and may prove cost-effective in existing urban areas. WATER POLLUTION AND HEALTH HAZARDS Water pollution is a serious problem in the majority of the developing countries. A high propertion of domestic and industrial effluents are untreated and discharged directly to watercourses, irrigation canals and drainage ditches (Brikett, 1999). Treated effluents usually do not meet the stringent standards for disposal to watercourses. This is an acute difficulty that needs remarkable capabilities and comprehensive efforts to overcome. In Egypt no guidelines have been adopted but the law 48/1984 prohibits the use of effluent for irrigation crops unless treated to the required standards of agricultural drainage water. The irrigation of vegetables eaten raw with reclaimed water, regardless of the quality level, is forbidden. Some Egyptian standards for discharge of treated wastewater into watercourses are listed in Table 2, in which biochemical oxygen demand (BOD) is considered the single most important water pollutant. However, high proportion of urban water in the eastern delta is untreated and discharged directly to drainage ditches. Health problems arise due to seepage flow from such ditches of high water levels to groundwater and infiltration into neighboring irrigation canals. Table 2: Standard Maximum Measures, mg/l. Parameter Non-fresh water ways Fresh waterways BOD Dissolved oxygen Oils Dissolved solids Suspended solids 60 not less 4 10 not more 2000 50 6 5 0.1 500 --- The standards for the reuse of sanitary drainage water and degree of treatment are summarized in Table 3. The standards are defined for three groups of wastewater: group 1effluent of primary treatment; group 2- effluent from secondary treatment; and group 3- water that has received advanced treatment. Table 3. Maximum Criteria for the Reuse of Reclaimed Water and Degree of Treatment in Egypt mg/l Group 1 (Primary) 300 Group 2 (Secondary) 40 Group 3 (Advanced) 20 mg/l 350 40 20 --5 --up to 2,500 up to 5 up to 350 10 1 100 up to 2,000 up to 3 300 5 1 100 up to 2,000 up to 3 300 Parameter Unit BOD Solid Suspended Substances Oils Intestinal Nemotodes Fecal Coliform Total Sodium Boron Chlorides mg/l cells/l number/100ml mg/l mg/l mg/l A recent study has been carried out at Alexandria University to investigate the impact of effluent disposal on receiving drains for four secondary wastewater treatment plants (TP) and BOD removal efficiency. Each of the receiving drains is a stretch with the wastewater TP as a point source of BOD. Brief sample results are presented in Table 4 (personal communication). Of the four TPs, two use activated sludge and the other two use trickling filters, and their design capacity ranges from 12,000 m3/day to 90,000 m3/day. BOD concentration in the effluent of three out of four plants exceeds the maximum of 60 mg/l for discharge to nonpotable surface waters (48/1984 Law). Downstream BOD concentration reflect selfpurification. Table 4: BOD concentration, in mg/l, showing the impact of effluent on drains Wastewater sampling point Treatment plant Damanhour, Receiving drain El-Khairy Amina Omer Deshaoudy 15 472 83 34 9 325 30 13 7 650 77 26 23 217 75 21 Upstream the TP TP influent TP effluent One km downstream the TP Abou El Matamir Samannoud Kafer ElDawar The GOE is taking steps to overcome some of the most pressing problems associated with reusing wastewater by removing the industrial component or treating it thoroughly at the source, before admitting it into the principal sewage networks or discharging it into the waterways. An industrial treatment project is currently under way that covers some 200 plants, classified according to their effluents, discharge system and outlets. Those discharging directly into the Nile subsidiary branches are given the highest treatment priority. Others with less or indirect impact on the environment or public health are given second or third priority (Eid, 1988). Steps have been taken to establish some major pilot projects on the use of reclaimed water for agricultural production. For example, new sewers of Greater Cairo will be able to treat up to 4 million m3/day, that could irrigate 400,000 acres of desert lands. A pilot project was launched in Abu Rawash area (Giza) aiming at investigating the environmental impact, with special emphasis on health aspects, chemical and physical effects on the soil, groundwater reserves, crops, and on workers and local population. Conditions in the area were monitored for four consecutive years. Positive and negative effects were recorded. The positive effects include increased organic matter in the soil from 0.1 to 0.5%, with marked improvement in the soil properties, nutrient absorption, water holding capacity and cation exchange capacity. The yield for an experimental crop of maize increased from 700 to 2000 kg/acre. Negative effects include accumulation of heavy metals in the soil and crops, increased nitrates in groundwater and health hazards to workers. Cases of hepatitis, dysentery and nematoid infestation and other diseases were reported over the four years of the investigation (Khalifa, 1997). WATER CONSERVATION Water shortages necessitate the development of innovative demand management beside supply enhancement measures. Water conservation practices have to be adapted to reduce the effects of water consumption on the environment. Urban water conservation methods include various forms of rationing such as fixed allotments to customers, percent reduction in supply, adoption of tiered pricing to control consumption, and rotation of service to customers (Lund and Reed, 1995). The major factor affecting the amount of diverted urban water for municipal use is the efficiency of delivery networks. The efficiency is as low as 50%in many urban areas in Egypt. Half of the diverted water is almost lost by leakage from the distribution network. Much attention is given to the rehabilitation of pipelines networks to reduce the enormous conveyance losses of good quality water. The use of synthetic materials for pipes in water distribution systems that are resistant to corrosion and wear are rather efficient. CONCLUSIONS AND RECOMMENDATIONS Threats of water shortage have induced the development of innovative demand management and supply enhancement measures. In developing countries, including Egypt, urban water management faces difficulties, which decelerate the rate of development and create health hazards. Financing problems arise due to the unbalance between high cost of urban water projects and funds limitations. Not much in-house expertise is present for planning, plant design or special equipment design and construction. Adopting a low level of treatment is desirable, not only from the cost point of view, but also in acknowledgement of the difficulties of operating complex systems reliably. However, the most appropriate wastewater treatment is that which will produce an effluent meeting the recommended quality guidelines both at low cost and with minimal operational and maintenance requirements. Field practice and consumer preferences seem to support continued growth of the nonpotable reuse option in future. In this context, dual systems have to be considered among the alternatives available for integrated water resources management. Nevertheless, notional guidelines and regulations on wastewater reclamation and reuse have to be established. REFRENCES Abd El-Naim, M. (1988). Using sewage water for irrigation. Proceedings of the Regional Seminar on Strengthening the Near East Regional Research and Development Network on Treatment and Reuse of Sewage Effluent for Irrigation. 11-16 December 1988. 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