Pilot Project on the Use of Treated Wastewater for Irrigation at the Iaat Wastewater Treatment Plant in the Beqaa Valley, Lebanon
The Beqaa Valley in Lebanon is an important agricultural area that, like most of the Middle East, faces problems of water shortage. The use of treated wastewater for irrigation purposes could ease this situation, however. FAO implemented a pilot project between 2011 and 2015 to research the use of treated wastewater from the Iaat wastewater treatment plant. The project concluded that wastewater is an important source for irrigation in the area, and can even enhance yields, but also that farmers need to take precautionary measures if treated wastewater is used in fruit and vegetable production. An upgrading of wastewater treatment capacity at the Iaat plant is also recommended.
The Beqaa Valley is Lebanon’s most important farming region. Like other agricultural regions of the arid Middle East, there is a shortage of water in the Beqaa Valley, and climate change projections forecast that this region of Lebanon will be most adversely impacted by higher temperatures (leading to higher rates of evaporation) and less precipitation. At the same time, this region is critical for the country’s food supply. In these circumstances, the reuse of treated wastewater for irrigation purposes is a priority.
Conflicts arising from the baseline situation
Groundwater resources are scarce at the case study site. The groundwater level keeps dropping, making it more expensive to abstract it, and some farmers claim that other farmers use too much groundwater. In the absence of an established and accepted allocation algorithm, coupled with proper monitoring and enforcement, future conflicts between farmers are likely to take place.
Description of the applied measure, its introduction and operation
Water use productivity in agriculture can be enhanced in a variety of ways, including: crop choice, soil and irrigation management, reducing water loss, and using treated wastewater (the project focus is on the latter).
Within the project, a capacity building workshop took place to facilitate the dissemination of information on good agricultural practices and the safe use of treated wastewater. The workshop included training on wastewater treatment technologies, so that participating farmers would become familiar with processes that ensure compliance with wastewater standards for irrigation. Farmers also learned how treated wastewater can be applied for irrigation, compared to fresh water irrigation (e.g. different needs depending on fertiliser types). Since the direct use of wastewater can pose health risks to farmers and consumers of treated produce, it is especially important to educate farmers about these risks and how they can be managed.
In 2011, FAO helped the Government of Lebanon through another project to establish guidelines on wastewater reuse. The resulting conclusions are contained in the table below. (See table)
The Iaat Wastewater Treatment Plant was selected out of 15 potential plants in the Beqaa Valley to serve as a pilot site. Selection was based on criteria such as capacity, location, and number of farmers potentially served. The Iaat Wastewater Treatment Plant is a secondary treatment plant with a design capacity of 12,000 m3 per day of sewerage inflow, serving up to 88,000 people in line with the expansion of the sewer network in five communities: Baalbeck, Iaat, Douris, Ain Bourdai, and Haouch Tell Safiyé. The plant was constructed in 2007 by the Council for Development and Reconstruction (CDR). The investment was financed with funds supplied by the World Bank. The plant is managed by the Beqaa Water Establishment, which hired a private contractor (the Farhat Group) to operate it.
Sewerage volumes exhibit high seasonal variability. Inflow in the winter can exceed plant capacity, while in the summer it can drop to below 1,000 m3 per day due to illegal tapping of the sewerage network by farmers who would rather use untreated wastewater for irrigation than no water at all.
The project was preceded by a socio-economic survey of farmers and their households to gain a better understanding of their status and current agricultural practices, and of how the use of treated wastewater might impact them. About half (22 of 45) of the visited households agreed to participate in the 148-question survey, and the resulting conclusions were: average land size is about 10 hectares, and farmers essentially cultivate all their land; farming is the main occupation for most household heads; the area around Iaat is rather fertile, allowing a wide variety of crops to be cultivated, but the availability of water is a limiting factor; only about one-third of the land is irrigated, and access to fresh water is expensive because boreholes are quite deep; barley is an important crop, mainly because of its resistance to drought; about a quarter of the farmers interviewed already used treated wastewater for irrigation, and 90 percent of the remaining farmers are willing to use it, mainly as an alternative to expensive and not always available fresh water sources; farmers noted that groundwater levels are lower and abstraction costs higher; there are also problems related to power supply, therefore pumping is not always an option; access to groundwater is made difficult by its scarce availability; and signs of water pollution were also mentioned.
The goal of the project was to inspect the feasibility of irrigation with treated wastewater and to develop guidelines for the future. As such, two groups of farmers were created, one group using fresh water, the other using treated wastewater for irrigation. Three farms participated in each group , and the average farm size was about 0.6 hectares.
The research showed that the yield of aubergine (eggplant) irrigated with treated wastewater was 19 percent higher than aubergine irrigated with fresh water, which was probably due to the presence of nutrients in the wastewater. With respect to soil quality and crop quality, no conclusions have been published so far. However, several recommendations have been put forward for aubergine producers:
- Gravel filtering should be applied to the water;
- Soil quality is to be regularly analysed;
- Over-irrigation can result in adverse impacts (a maximum of 20 mm of water every 2-3 days is sufficient);
- Protective clothes and gloves should be worn when working with low-quality water; and
- In order to get rid of bacteria, harvested fruits and vegetables should be retained for 1-2 days before sending to market.
Regular analysis of the effluent confirmed that the treated wastewater is “Category III” (based on the above table) and not suitable for producing vegetables. However, vegetables are a key source of income for the farmers in this region, and they are unlikely to give it up. Therefore, one important conclusion of the study is that wastewater should be treated to a higher standard, which (based on the assessment of the project experts) is not at all unrealistic. Since many farmers have been using untreated wastewater, even for vegetable irrigation, shifting water use from untreated to treated wastewater would already be an important development.
Physical and ecological impacts of the measure
Treated wastewater is a reliable form of water supply that allows irrigation in all seasons, as long as untreated sewerage is not tapped illegally for irrigation. It also contains nutrients that can improve crop yields. Precious fresh water can be saved by enhanced use of treated wastewater.
Financial and other impacts of the measure on different stakeholders
As a result of using treated wastewater for irrigation, the pumping costs of farmers can decrease to the extent they replace ground water pumped from deep boreholes.
Scarcity of fresh water limits the choices of additional water supply, giving treated wastewater an economic value.
Enhanced aubergine yields have been registered during the project in case of irrigation with treated wastewater.
Resilience of achievements, sustainability of results
Sustaining the current project is relatively easy, so long as the irrigation equipment does not require replacement. Upgrading the wastewater treatment plant to a standard under which the effluent would comply with “Category I” requirements for irrigation could require additional external resources.
- Gained experience, based on which guidelines have been developed for future uses of treated wastewater for irrigation, thereby contributing to safe, large-scale utilisation of sewerage.
- Education of participating farmers on wastewater technologies, irrigation equipment and safety issues with respect to the use of treated wastewater in agriculture.
- Thorough and impartial analysis.
- Enhanced crop yield due to use of treated wastewater instead of fresh water.
The experience gained from the project can be used for more effective and safer utilisation of treated wastewater elsewhere in the MENA region.
- USD 2,373,000, which included research, capacity building irrigation technology provided to participating farmers