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<International Source Book On Environmentally Sound Technologies
for Wastewater and Stormwater Management>

2.4 Reuse (Topic d)

Treated wastewater is now being considered as a new source of water that can be used for different purposes such as agricultural and aquaculture production, industrial uses, recreational purposes and artificial recharge. Using wastewater for agriculture production will help in alleviating food shortages and reduce the gap between supply and demand. The interest in the reuse of treated effluent has accelerated significantly in the West Asia region since 1980 for many reasons;

  • Expansion of sewerage system networks and the increasing number of treatment plants.
  • Production of large quantities of wastewater which makes its use for agriculture a viable alternative.
  • Wastewater is a rich source of nutrient and can reduce the use of fertilizers.
  • The reuse is a safe disposal of wastewater which will reduce the environment and health risks, and
  • The treatment of wastewater to be used for irrigation is cheaper than that needed for protection of the environment. Regulations to discharge water into sea and streams or groundwater recharge are more strict than reuse for irrigation.

In addition, the reuse potential in West Asia countries is very high due to the extreme water scarcity. Now, there are at least eight countries in the region that operate modern wastewater reuse facilities for agriculture production. About six countries are practicing reuse in unplanned uncontrolled and direct use for irrigation without restriction. In Yemen, Syria, Lebanon, Palestine Territories, Egypt and Iran, raw sewage is being used for agriculture production. Three countries in the region discharge raw wastewater to the surface water (rivers) without considering management of reclaimed water as a source. In Bahrain, about 12MCM of tertiary treated wastewater is used for irrigation of fodder crops in a government farm. Some private farmers are using treated effluent for the production of alfalfa. At present the remaining part of their 50MCM treated effluent is discharged to the sea. The government of Bahrain is planning for full utilization of the treated sewage effluent for irrigation purposes by the year 2005. This of course will reduce the pressure on their already mined groundwater resources.

In Egypt, the practice of reuse of wastewater started in Cairo city in 1911 to irrigate Jabal al-Asfar farms covering an area of 1260 hectares. In 1994, about 200MCM of treated wastewater was estimated to have been used for irrigation; the rest of about 450MCM was discharged to surface water bodies of the Nile, drainage canals and the sea. By the year 2000, the treated wastewater production will reach a potential of 4.9BCM per year. This amount is planned to irrigate an area of about 400,000 hectares of desert land.

In Jordan, the volume of treated wastewater produced in 1998 reached 74MCM per year, of which about 95% is reused for irrigation. The reuse of treated wastewater in Jordan reached one of the highest levels in the world. About 80% of the treated effluent is discharged to Zerqa river where it is collected and stored downstream in King Talal Dam to be used for restricted irrigation in the southern part of the Jordan Valley. The remaining 20% which is not located within the Zerga river watershed, is reused on-site. The treatment and reuse of this vital resource is well organized. Future plans aim at improving the quality of effluent and expanding its reuse in other areas in the upland.

In Kuwait, about 25% of its agriculture and green areas is irrigated using 52MCM of treated wastewater. The rest is either used for artificial groundwater recharge through basin filtration or being discharged to the sea. For the rest of the Gulf States, the future aim is to achieve a high quality effluent through secondary and tertiary treatment for irrigation of green areas and ornamental trees in the streets.

In the Palestinian Territories (West Bank and Gaza), the untreated effluent was used for irrigation of trees and vegetables in an uncontrolled manner. The situation will improve in the future with the heavy involvement of donor agencies and the Water Authority in reconstructing the whole water supply and sanitation infrastructure.

The trend in other countries like Lebanon, Syria, Iran, Iraq and Yemen is to expand the use of wastewater for irrigation. In Iran, for example, there is about 70 MCM of primary treated effluent that is used for irrigation. The new management reform action related to the water sector considers wastewater as a new source that should be used for irrigation.

Farmers in Yemen living near discharge sites of wastewater in major cities like Sanaa and Taiz are practicing reuse of non treated or partially treated effluent. Wastewater from the waste stabilization pond near Sanaa Airport is conveyed through open channels to agriculture plots where farmers use the water for irrigating maize, wheat and barley. At present, there is a continuous development in Yemen to implement sewerage networks and treatment plants. The produced wastewater can reach 40MCM by 2005 where it will be used for irrigation.

Artificial recharge of groundwater is another option for reuse of reclaimed wastewater either directly or indirectly. By this, the already over exploited aquifers in the region can be restored. Few cases of artificial recharge have reported in the region; especially in Oman, Egypt and Jordan.

The cities of Ismailiyah and Suez of Egypt and Aqaba of Jordan use the effluent of their wastewater stabilization ponds for artificial recharge of groundwater via rapid infiltration basins.

Table 2.5 summarizes the current type of reuse in the West Asia region and describes the level of treatment and restriction regulation on crop selection and disposal to the sea. The reuse opportunity potential in West Asia is very high due to the following conditions:

  • Extreme water scarcity, which affects economic development with little chance to create feasible alternatives for a water supply having excellent quality and competitive price as in the case of reclaimed water.
  • Wastewater is a good reliable source and if there is a good design for reuse, there will be no health problems expected.
  • The reuse capital investment can be paid back with a reasonable period for both suppliers and users.
  • The socio-cultural acceptance is there.

In most West Asia countries sewage effluent provides a convenient and economic source of water for irrigation. In the last decade there has been a significant move to formalize health risks and use the treated effluent with the highest possible efficiency. In addition to wastewater being reused, nutrients can be recycled through irrigation as well. This will protect water bodies from eutrophication and will at the same time use the fertilizer value in the reclaimed wastewater to meet the fertilizer requirements of a wide range of crops.

Table 2.5: Summary of existing and proposed re-use installations in West Asia countries
Country Reuse application  Level of sewage treatment  Policies
Roads Parks Indust Aqua-culture Agri. AR Primary Second-ary Tertiary
Bahrain         *     *   O3+ R
Egypt       * * * * *   ND
Iraq             * *   To river
Jordan         * *   *   R
Kuwait         *     * * R
Lebanon         *   *     ND
Oman *       * *   * * R
Qatar *  *             * TI
Saudi Arabia *    *   *     * * O3+ R
Syria         *   *     ND
UAE         *   * *   O3+ R
Yemen         *   *     ND
AR: artificial recharge
ND: not decided
R: restricted
TI: trickling irrigation

Using reclaimed wastewater in urban areas is not practiced so far, but it appears that reclaimed wastewater reuse in urban areas for toilet flushing and street cleaning is feasible. This is because the majority of countries in the West Asia region face an increasing growth of high-rise buildings, where reuse for toilet flushing is a promising option, since it is the most economic application method for highly-populated urban areas, if a nearby agricultural area is not available. In West Asia countries there are three cities of over three million people, according to 1996 statistics, where this method can be applied. Decision-makers of local authorities must consider this option as a technically feasible option.

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