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United Nations Environment Programme
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Newsletter and Technical Publications
<International Source Book On Environmentally Sound Technologies
for Wastewater and Stormwater Management>

2.11 Case studies (Topic k)

2.11.1 Jordan's experience in treated wastewater reuse

Introduction

Jordan is an arid to semi arid country with a total area of approximately 89,400km2 featuring variable topography. A mountain range runs from north to south; the land slopes gently to the east of the range forming the eastern desert; but to the west, the land slopes steeply towards the Jordanian Valley where the Dead Sea lies at an elevation of - 400m below sea level.

The country water resources are scarce and are directly dependent on the annual rainfall, which varies from 50mm in the eastern desert to about 600mm in the northern mountain. The total available water resources as of 1998 can be estimated at 900MCM per year. With a population of 4.75 million, the per capita share of water is about 190m3/c/year which is consided to be among the few countries of the world with such a high level of water scarcity. About 600MCM is used for agriculture and the remainder is used for domestic purposes (250MCM), industrial sector (40MCM) and other uses (10MCM).

According to the national water allocation policy, priority of water supply is given to domestic users followed by industry and the remaining will be for agriculture. As such, it appears that the share of agriculture will drop significantly in the future. The decrease in water allocation for agriculture can be compensated partly by treated wastewater effluent.

Development of sanitation services

Until 1969, cesspools, septic tanks and other on-site methods were used for the disposal of wastewater. This practice coupled with rapid and uncontrolled population growth resulted in major environmental problems especially surface and groundwater pollution. The government of Jordan has realized the magnitude of the problem and the necessity to build a safe disposal system for wastewater. In 1969, the municipality of Amman completed a sanitary sewage system to serve Amman population of 500,000 people. This system was associated with a conventional activated sludge plant with a capacity of 60,000 m3/day and a BOD loading of 18,000 kg/d. The design effluent standard BOD was 20mg/L and the effluent was discharged to the major tributary of Zerqa river.

Due to the high strength of raw sewage (BOD5> 600mg/L), the effectiveness of the plant was drastically reduced to the extent that the actual capacity became only 30,000m3/d by the year 1980. The operation under high hydraulic and organic loading conditions resulted in an effluent that could not meet the standard of BOD5<20mg/L and low efficiency in the process of solid processes and disposal. As such, the quality of surface and groundwater was deteriorated. This was subsequently used for irrigation downstream.

In the 1980s, the government built a major wastewater stabilisation pond (WSP) system for the Greater Amman Area and other treatment facilities in major cities and towns in the country totaling 14 treatment plants. By 1998, about 50% of the plants were overloaded including the largest WSP of Amman. The government has completed a master plan study to upgrade and expand existing facilities and to build new plants in the country aiming at 90% coverage of the population by the year 2010.

Reuse

At the national level, the total production of the treated wastewater is about 72MCM as of 1998. Nearly all these amounts are being reused mainly for agriculture (95%), about 3% for groundwater recharge and 2% for industrial uses. This practice is a result of the government policy so as to conserve water as a scarce and valuable resource.

Historically the indirect reuse of wastewater effluent has been practiced in Jordan for a number of years, as it has been discharged into the main wadis and mixed with the surface flow. Farmers along the banks of these wadis used to pump water or direct the flow of the wadis and reuse it for unrestricted irrigation. Natural recharge to aquifers takes place through wadis beds. The direct and controlled reuse of treated effluent in Jordan has been increasing since 1985. The government of Jordan has introduced new legislation on effluent quality to control its use considering public health issues and protection of the environment. It is mandatory that all treatment plant projects must include a fully designed and feasible reuse scheme. Below is a brief description of reuse schemes that are currently in operation.
Zerqa River Basin Scheme is the largest reuse system in operation in Jordan. There are four treatment plants located in the basin that discharge its treated effluent to Zerqa River where it is collected downstream at King Talal Dam and used for restricted irrigation in the southern section of the Jordan Valley. The largest treatment plant is As-Samra waste stabilization pond treating about 60MCM where most of it joins the flow at Zerqa River. A small portion (2%) of this effluent is used in on-site irrigation of about 1000 hectares planted with olive trees, fodder crops and forest trees. The other plants (Jarash, Abu Nuseir, and Baqaa) discharged about 4.0MCM to the same river. The volume of wastewater contributes to about 55% of Zerqa Rivers annual yield of 110MCM. King Talal Reservoir with a capacity of 85MCM collects surface runoff and treated sewage effluent which means its quality varies from summer to winter. The total irrigated area by the reservoir water could reach 10,000 hectares.

The volume of domestic treated wastewater from Aqaba WSP reached 2.5MCM in 1998. About 1.5MCM is used for irrigating palm trees and the rest is used for artificial recharge using infiltration basins. As for the reuse in Ramtha, Maan, and Madaba; these three plants are served with three WSP producing about 3.5MCM (1998) where it is used for irrigating fodder crops and trees.

The rest of the plants (Salt, Tafilah, Karak, Irbid and Kufrenjih) treat about 6MCM. Where their effluents join the stream of wadis. This water is also used by downstream users for irrigation or collected in small dams, which are built on the wadis for later use in irrigation.

There are about 6 small domestic treatment plants serving the residential areas of the employees of major industries (Cement, Phosphate, and Potash) providing about 1.5MCM of water. Some of this water is used for on-site irrigation and the rest is reused in industries for cooling purposes.

Industrial water from the two major industrial cities (Sahab and Al Hassan) is treated separately and is used for on-site irrigation. Scattered industries, whose influent could not join the domestic wastewater, are using their industrial effluent for on-site irrigation like the yeast and paper factories. The effluent of hazardous industries like paint, batteries, chemicals and pharmaceutical are disposed through evaporation or incineration. Phosphate mining and processing is considered one of the main industries in Jordan, which consumes about 20MCM of water. Recently, the processed water has been recycled after settling and filtration. Also, the effluent of treatment plants of Amman Airport and Al-Hussein Medical City are used for irrigation of grasses, green areas and forest trees in the vacinity of the two sites.

Research and reuse

The Water and Environment Research and Study Center at the University of Jordan is a leading research institute carrying out a comprehensive research program on the reuse of treated wastewater for agriculture and other purposes. The research varies from large-scale surveys and baseline studies to field plot experiments and laboratory analysis. The research program started in 1985 of conducting integrated studies of the potential of reuse and its impact on the health and the environment. These studies were conducted on the treated effluent of Amman Airport where an experimental site was selected nearby representing the arid conditions and low rainfall areas. Results showed improved yield production of corn, no salt accumulation, and slight increase in heavy elements concentration in the leaves.

Another experimental site at As-Samra WSP site has been established since 1992 where an intensive research program is conducted. The research program concentrates on selection of proper irrigation method, cropping patterns, salt and heavy elements' concentrations in the soil, different management practices and socio-economical aspects. Potential of growing alternative crops (such as sugerbeats, alfalfa, Sudan grass and local grazing shrubs) showed promising results. Higher yield was obtained using wastewater especially when sound water and soil management has been practiced.

All of the other research activities, dealing with testing low treatment technologies, have reuse components. The effluents of the anaerobic UASB reactor and the constructed wetland are being reused for irrigation. Survey and analysis comparing olive trees irrigated with fresh water with those irrigated with wastewater over 12 years are being investigated.

In 1993 a base line survey of the area of southern Jordan Valley was conducted monitoring soil chemical properties and heavy elements concentrations. This area is irrigated with the release of King Talal Reservoir; a mixture of 1:1 wastewater to flood water. This survey will be used as a background comparison for future studies to evaluate impacts of wastewater irrigation. Masters students are encouraged to conduct their research on this area to investigate any future changes in the environmental parameters that might occur. Socio-economic studies on farmers' behavior and acceptance of using treatment effluent for irrigation are under way by a Ph.D. student

In Bahrain, wastewater of five major cities and districts are treated at the main activated sludge treatment plant at Tubli. This plant receives by tankers the septage of the smaller towns and villages that are dependent on septic tanks. The Tubli treatment plant is overloaded, now receiving an estimated 160, 000 m3/day as an average flow compared with the average design flow of 125,000 m3/day. This is having an adverse effect on the operation on the plant in terms of the biological quality of the secondary effluent transferred to the tertiary system. The peak flow during peak hours can reach 200,000 m3/day . Therefore activated sludge from the secondary clarifiers is carried out to the tertiary filters in excess of the design flow rate. As such the bulking sludge is carried over the outlet weirs. The effect of the sludge carry/ over to the tertiary treatment system is that the filters become rapidly blocked and, as a result, pass through significant numbers of parasites. In the effort to overcome this problem, it is recommended that the capacity of the tertiary process be expanded to 160,000 m3/d at this stage. For the future, the primary, secondary, and tertiary facilities at Tubli are expanded to 200,000 m3/d (year 2010 estimate). In addition to the Tubli plant, there are nine other independent sewage treatment plants in the country, which use trickling filters or activated sludge technology; one of them is for the University of Bahrain with a capacity of 8000 m3/d.

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