TOWARDS CIRCULAR AGRICULTURAL SYSTEM: WASTEWATER MANAGEMENT
In the Lebanon-based case study of the Mediterranean wAter management solutions for a sustainable aGriculture supplied by an Online collaborative platform (MAGO) project, AUB’s FAFS will pilot an interactive web map tool that serves as a new water reuse system with forecasts and updated data to encourage evidence-based decisions on water reuse between the main users of this tool including farmers, wastewater treatment plant (WWTP) operators, donors, and policymakers. The tool or application is guided and informed by farmer data on crops and water requirements, WWTP operator data on quantity and quality of treated wastewater (TWW), donor data on services and capacities in wastewater treatment, government and policymaker data on policies and regulations for TWW reuse in agriculture. The tool is in its development phase and is being co-created in an active participatory approach with a select WWTP operator in the Bekaa Valley, which supplies the only existing TWW reuse network that is known in Lebanon. It aims to increase connectivity, encourage accountability and serve as a decision-support tool towards a circular agriculture system.
Severe and prolonged political and economic mismanagement in Lebanon has led to currency devaluation, high inflation rates, and an energy crisis that has forced electricity and mobility to only be available at exorbitant financial and environmental costs further aggravating existing water and food insecurity. Treated wastewater reuse in agriculture presents one effective substitute for fresh water assuming safe reuse practices and proper treatment processes. Ongoing monthly quality assessments of the physical, chemical and microbiological properties of TWW from four WWTPs in the Bekaa Valley indicate that this TWW is limited to irrigation of fruit trees for canning, cereals, fibres and industrial crops.
To generate more evidence on TWW reuse in agriculture in the Lebanese context, the case study’s experimental demonstration involves growing corn and potato using secondary and tertiary treated wastewater at AUB’s Advancing Research and Enabling Communities center in the Bekaa Valley. This time between July and October is considered the driest season when farmers are more likely to search for a sustainable and affordable substitute to groundwater. This experiment is designed as a randomized plot that involves irrigating with each of the two treatments of secondary and tertiary treated wastewater and with fresh water as a control. Data generated from this experimental plot and its yield will be featured in participatory farmer workshops to promote TWW reuse in agriculture planned for December 2022.
Interviews with Bekaa-based farmers and the general Lebanese consumer showed that 95% would accept the safe practice of TWW reuse in agriculture. Farmers perceive the leading benefit as increased crop yield while consumers perceive the leading benefit to be reduced pollution in water bodies. Can TWW substantially cover the water requirements during the dry season and under climate change projections in the near future? Considering a case study on the town of Ablah, home to the only existing and known TWW reuse network in Lebanon, we identified that TWW in Ablah currently covers only 10% of the estimated gross water requirements for crops including grape, wheat, and potato projected to decrease to 7% under climate change scenarios.
This is barely enough and necessitates the consideration of other solutions for limited resource settings. Preliminary results from the first season of Azolla Pinnata cultivation in primary, secondary and tertiary treated wastewater showed that primary treated wastewater, the most nutrient-dense, yielded the highest growth and effectively purified the water from ammonium and phosphorus. The second season is to explore the potential of Azolla in purifying wastewater at different levels and its feasibility as locally produced animal feed promises sustainable management of water resources and could contribute to food security and a circular economy by promoting reuse and waste elimination. The results of this study serve as scientific data for similar initiatives in removing contaminants from wastewater.
Finally, Lebanon is uniquely positioned to address TWW reuse in a limited resource setting within a fragile socio-economic and political environment.
Image: Azolla pinnata yield from Season 2 growing in positive control water (freshwater + fertilizer)