Treated Wastewater Management and Reuse: Abu Dhabi Emirate Case Study MOHAMED DAWOUD

Advisor, Water Resources, Environment Agency – Abu Dhabi

United Arab Emirates

Introduction: In arid regions treated wastewater is an environmental, social, and economic

resource that needs to be managed in appropriate way. Reusing of treated

effluent that is normally discharged to the environment from municipal

wastewater treatment plants is receiving an increasing attention as a reliable

water resource. The volume of this resource is being considered in the planning

and implementation of water resources projects. Irrigating agricultural crops

with recycled wastewater has been practiced in arid and semi-arid regions and is

rapidly getting popular in the countries of the Arab Regions. In the last three

decades, rapid economic development coupled with population growth and

large agricultural sector expansion have forced the government to rely on non-

conventional water resources such as desalination and treated wastewater as

secondary sources for irrigation water supply. Treated wastewater has the most

potential as marginal water suitable for growing forages, landscaping, fruit

orchards and non-vegetative crops. In Abu Dhabi Emirate, the annual

production of treated wastewater is about 250 million cubic meters produced by

32 tretment plants as shown in Figure (1) which is about 7.2% of the total

Emirate water production. Only about 60% of the treated wastewater is reused

in wetlands, landscaping, and recreation areas due to the capacity of distribution

system after treatment.

Figure 1: Location of Wastewater Treatment plants in Abu Dhabi

Abu Dhabi Emirate is an arid region where the average annual rainfall is less

than 100mm. The water resources components found within the Emirate are

traditional or conventional resources (rainfall, springs, wadis, lakes, and

groundwater) and non-traditional or unconventional resources (desalinated

water and treated wastewater). Groundwater occurs in the Emirate as either

consolidated or unconsolidated surficial deposit aquifers or as

bedrock/structural aquifers and contributes 63.6% to the total water demand,

followed by desalinated water (29.2%) and treated wastewater (7.2%) as shown

in Figure (1). Groundwater supply is decreasing and the imbalance between

supply and demand is being filled by ever increasing amounts of desalinated

water. Although wastewater reclamation and reuse has been recognized as a

promising strategy to alleviating water scarcity and reducing the impacts on the

environment, the actual reuse of treated wastewater is rather limited. In Abu

Dhabi Emirate only 60% of the total treated quantities are reused and the rest

are discharged to environment as show in Figure (2).

Figure 2: Water Resources in Abu Dhabi Emirate.

Present Wastewater Production and Use Wastewater initially provided the bulk of the water for amenity and landscaping

purposes. However, as the volume increased from the 1990s supply outstripped

the irrigation systems capacity to fully utilize it. Where this occurred irrigation

shortages were made up from desalinated water. The fact that desalinated water

is seven times more expensive to produce had no impact on this allocation

because it was free for municipal uses. Thus there were few incentives to better

manage the recycled water supply or remove the constraints in the distribution

network. Independent calculations of irrigations application in the Abu Dhabi

area put current use at 4,800 mm/year – at least double the amount needed for

urban greening. Until recently the main drawback of the 200 km distribution

network on Abu Dhabi Island was the relatively small size of the pipes. In

addition, the flows are still controlled manually and water is not properly

budgeted and storage reservoir operation (and there are 119 storage reservoirs)

is haphazard – some reservoirs receive excessive flow while others get no flow

at all or very limited flows as shown in Figure (3).

Figure 3: Water Resources Use in Abu Dhabi

Future Wastewater Production and Use

“Learning from land and water projects experiences for smart management”

15-18 December 2013 (Amman-Jordan)

Total Production

240 Mm3/y

32 Plants Greening, Amenity

Plantation 120 Mm3/y

To Arabian Gulf

100 Mm3/y

To sand dunes (al Ain)

10 Mm3/y

Total Production 350 mM3/y

32 Plants Greening and amenity

120 Mm3/y

Advanced Treatment

Agriculture and Forestry

230 mm3/Year