Feasibility Study for Constructed Wetlands in the Litani River Basin

The study aimed to assess the potential for constructed wetlands to improve water quality in the basin. The Litani River Basin is essential for agriculture, urban development, and industry in Lebanon and suffers from widespread water pollution due to lack of pollution regulation and enforcement, few operable wastewater treatment facilities, and environmentally damaging agricultural practices. The major sources of water pollution in the basin are wastewater releases from domestic, industrial, and agricultural sources as well as solid wastes and leachates. Treatment wetlands are systems that harness physical, chemical, and microbial processes found in natural wetland environments to remove pollutants from wastewater. These systems have been in use for over 60 years and have seen widespread advancement in the past two decades as a viable option for controlling water pollution with little to no conventional energy input and potential for greatly reduced operations and maintenance demands relative to traditional technologies. NewFields conducted reconnaissance in the Litani River Basin and identified four potential treatment wetland sites. These sites were evaluated for their logistical, technical, and engineering feasibility and preliminary wetland concepts and cost estimates were developed for each site. The four sites evaluated include the LRA-owned parcel along the Litani River near Joub Jannine, the Tannayel dairy farm, the Liban Lait dairy farm, and the Berdaouni River above the city of Zahle. The Joub Jannine site was selected as the preferred site due to its proximity to an untreated wastewater outfall, public ownership, and availability of land adjacent to the Litani River. A treatment wetland sited here would provide improved water quality downstream to Qaraoun Lake and Canal 900. The site also offers significant potential for environmental education, wetland habitat restoration, and other ancillary benefits. A preliminary plan for an approximately 3.5 ha treatment wetland facility was developed, expected to cost approximately $363,000. The proposed facility would occupy a significant area and would require substantial investment. However, the potential benefits of improved water quality and environmental education make it a viable option for the Litani River Basin. The Tannayel dairy farm offers two potential options for treatment wetlands. One opportunity would treat diverted water from the Chtaura River that feeds an on-site lake used for irrigation water storage. This wetland would improve water quality used to irrigate crops on the farm by converting a corner of the lake into a treatment wetland and increasing habitat diversity in the process. The second opportunity would treat dairy production wastewater that is currently disposed of in a septic system. The proposed irrigation water treatment system would occupy approximately 5000 m² and cost approximately $379,000. The dairy treatment wetland would occupy 1 hectare and cost approximately $96,000. These options offer potential for improving water quality and reducing the environmental impact of the dairy farm. The Liban Lait dairy farm is Lebanon's largest dairy farm and currently pipes over 500 m³/d of high-strength wastewater directly to the Litani River. A pilot-scale treatment wetlands to remove organic matter and nutrients from this point source discharge could be created as a demonstration that might eventually lead to wetland treatment of all produced wastewater at the facility. This pilot-scale system would occupy approximately 2 hectares, treat 10-20% of the total daily wastewater load, and cost approximately $186,000. This option offers potential for improving water quality and reducing the environmental impact of the dairy farm. The Berdaouni River above the city of Zahle flows through a series of cafés which are designed for outdoor seating on the river. During the summer months, untreated domestic wastewater from upstream causes a malodorous condition in the river that impacts the cafés business. Upstream of the cafés, a small number of floodplain terraces exist that have been developed as small-scale agricultural fields. One or more of these could be converted to a wetland system that receives diverted river water, removes pollutants, and discharges back into the river and may alleviate the odor problems. A 3000 m² terrace was evaluated for implementation as a treatment wetland system and is estimated to cost $68,000. This option offers potential for improving water quality and reducing the environmental impact of the river.