A new assessment of Southern Ghour, the district in Jordan’s Karak Governorate that lies below sea level at the lowest land elevation on Earth, estimates that the region’s agricultural residues, animal manure, and municipal solid waste could together deliver about 38.93 GWh of electricity per year when each resource is routed to its optimal conversion pathway. Using six-year averages from 2019 to 2024, the study calculates that the district generates roughly 31,554 tons of dry agricultural residues and 52,580 tons of recoverable livestock manure annually, alongside about 40,000 tons of municipal solid waste. Direct combustion of the dry residues and waste, with a combined available energy content of 462.77 TJ, is estimated at 25.72 GWh of electricity per year, while anaerobic digestion of manure and moist vegetable and fruit residues could yield 8.86 million cubic meters of biogas annually, equivalent to 18.60 GWh of electricity.

Southern Ghour covers about 465 square kilometers of the southern Jordan Valley and is home to more than 68,515 people. Its hot summers and mild winters, combined with extensive irrigation networks drawing on surface and groundwater, make it one of Jordan’s most productive agricultural zones, particularly for early-season tomatoes and bananas. In 2024, the district produced 64,750 tons of vegetables, 16,142.6 tons of fruits, and 5647.7 tons of field crops. Despite this output, the area is frequently cited among Jordan’s least advantaged localities, with high poverty levels, seasonal and labor-intensive farming, limited non-agricultural employment, and unstable incomes that the study identifies as barriers to sustainable development.

The local resource evaluation sits within a national energy system under visible strain. Jordan has relied primarily on natural gas for electricity generation over the past two decades and depends heavily on imported oil and gas. According to figures cited from NEPCO, peak demand grew by roughly 3.5% annually between 2014 and 2024, and in August 2025 the country set consecutive records of 4700 MW on August 11 and 4810 MW on August 14, surpassing the 4240 MW peak recorded in 2023. Nationally, prior assessments cited in the study estimate that Jordan produces more than 12.0 Mt of residue and waste each year, about 42% of which is recoverable for energy and biogas, with a theoretical biogas potential of 816.2 million cubic meters corresponding to 960.9 GWh of power.

Methodologically, the assessment transitions from a theoretical resource base to technically obtainable energy by applying accessibility and energy availability coefficients of 0.25 for agricultural residues, 0.75 for municipal solid waste, and 0.125 for animal manure, reflecting nationwide collection constraints in the absence of localized field data. Crop residue quantities were derived from reported residue factors, dry weight percentages, and availability factors, and their gross energy was computed from higher heating values, with species-specific calorific values drawn from greenhouse-grown vegetable residues under semi-arid conditions comparable to Southern Ghour. Biogas yields were set at 0.35 cubic meters per kilogram of volatile solids for cattle manure and 0.54 to 0.73 cubic meters per kilogram of volatile solids for vegetable and fruit residues, with a methane fraction of 0.60 assumed for digesters and combined heat and power efficiencies of 0.35 electrical and 0.45 thermal.

The species-level results highlight tomato waste as the district’s largest seasonal vegetable biomass resource. From 2019 to 2024, mean annual dry tomato residue amounted to 9945 tons with a calorific value of 14.58 MJ/kg, yielding a gross energy potential of 144,998 GJ before the availability factor, or 36,250 GJ of available energy. However, tomato residues carry 80 to 90% moisture, which limits direct combustion and makes biological conversion or co-digestion with animal manure more feasible. Among fruit residues, banana and date residues averaged 3969 and 990 dry tons per year with calorific values of 15.2 and 13.0 MJ/kg respectively, contributing 69.0% and 14.7% of the total available fruit energy of 21,899 GJ. Field crop residues from maize and lentils added 5226 dry tons per year, but their high lignocellulosic content hinders anaerobic biodegradability, so the study evaluated them solely through direct combustion.

Animal manure emerges as the dominant biogas feedstock. Goats and sheep account for 65.9% of the estimated 52,580 tons of recoverable manure per year, while cattle, despite representing a smaller share of the herd, carry a much higher availability factor of 0.90 because their waste is more readily collected. The study notes that manure in several local villages is stored or disposed of in open, uncovered areas where rainfall leaches it into the soil, creating risks of surface water and groundwater contamination. Municipal solid waste, meanwhile, is largely dumped at unregulated open sites lacking bottom liners, leachate management, or gas collection, a practice the study links to methane release, odor, and leachate infiltration into groundwater supplies that are especially vital in the water-scarce Jordan Valley.

The biogas pathway allocates the district’s moist organic resources to anaerobic digestion, producing an estimated 8.86 million cubic meters of biogas per year, of which animal manure contributes 59.9% and vegetable and fruit residues 40.1%. Converted in a biogas engine with a net electrical efficiency of 0.35, this corresponds to 18.60 GWh of electricity annually, with a further 23.91 GWh per year of useful heat at the assumed thermal efficiency of 0.45. The study observes that co-digesting manure with energy crop residues can enhance digestion by maintaining an optimal carbon-to-nitrogen ratio and reducing the risk of ammonia inhibition. At the national scale cited for comparison, biogas production in Jordan could generate 847.39 GWh per year of thermal energy at a conversion efficiency of 70%, and municipal solid waste is regarded as the most promising national biogas resource owing to available transport infrastructure.

The wastewater component of the framework is based on Jordanian design criteria of 80 liters of wastewater per capita per day. For the current population of 68,515, this corresponds to a flow of roughly 5481 cubic meters per day, projected to reach about 9444 cubic meters per day by the end of a 25-year design period as the population grows at 2.2% annually to approximately 118,048. Assuming water recovery rates of 85 to 95%, typical of decentralized treatment systems, the facility could deliver 1.70 to 1.90 million cubic meters of treated water per year at current flows, rising to 2.93 to 3.27 million cubic meters per year at the design flow. The covered anaerobic phase is estimated to produce 956 and 1648 cubic meters of biogas per day at the current and projected flows respectively, equivalent to 0.35 to 0.60 million cubic meters per year, with methane generation of 572 and 985 cubic meters per day at a 60% methane content.

The study recommends a decentralized waste stabilization pond-based facility, comprising a covered anaerobic lagoon for biogas collection, followed by facultative and maturation ponds, because it tolerates the fluctuating hydraulic and organic loads expected from tanker deliveries during any transition to a sewer system and demands far less energy than fully mechanical treatment. At present the district lacks a sanitary sewer network; residents rely on household septic tanks from which tanker trucks collect approximately 202,720 cubic meters of septage per year, a practice the study links to odor, spillage, and potential groundwater threats. Treated water is projected to comply with Jordanian JS 893 standards for restricted irrigation types B and C, suited to crops such as banana and date palms and maize, while the best initial strategy for the modest biogas volumes is capture and flaring to control odors and reduce greenhouse gas emissions, with combined heat and power deferred until post-commissioning measurements confirm economically viable gas yields.

Beyond energy supply, the integrated scenario of 38.93 GWh per year is estimated to avoid about 21,412 tons of carbon dioxide emissions annually by displacing fossil-fuel-based electricity at an emission factor of 0.55 kg CO2 per kWh. A systematic sensitivity analysis, varying feedstock availability, biogas yields, methane fraction, conversion efficiencies, and combustion efficiency within literature-derived limits, shows total electricity ranging from 18.93 to 62.63 GWh per year in combined low and high scenarios against the 38.93 GWh baseline. Biomass availability is the primary determinant, altering output by minus 25.0% to plus 22.0%, whereas the methane fraction and combined heat and power electrical efficiency impose relatively small impacts of plus or minus 4.0 to 6.8%, underscoring that improving residue collection and logistics presents the biggest opportunity to increase recoverable energy. The authors caution that their findings rest on secondary data and literature-based conversion coefficients rather than direct field measurements, and that implementation requires field-scale validation, pilot-scale evaluation of the proposed digestion and pond systems, and comprehensive techno-economic and environmental impact analysis before large-scale deployment in Southern Ghour or comparable arid agricultural regions.

Subject of Research: Integrated biomass-to-energy and wastewater resource recovery potential in Southern Ghour, Jordan

Article Title: Integrated biomass-to-energy and wastewater resource recovery in Southern Ghour, the lowest land elevation on earth: Opportunities for sustainable energy and water management

Article References: Al-Bawwat, A. K., Gomaa, M. R., Abu-Jrai, A., & Al-Muhtaseb, A. H. (2026). Integrated biomass-to-energy and wastewater resource recovery in Southern Ghour, the lowest land elevation on earth: Opportunities for sustainable energy and water management. Results in Engineering, 32, Article 113717. https://doi.org/10.1016/j.rineng.2026.113717

Image Credits: AI Generated

DOI: 10.1016/j.rineng.2026.113717

Keywords: Southern Ghour, Jordan, biomass energy, biogas, anaerobic digestion, direct combustion, animal manure, agricultural residues, municipal solid waste, wastewater treatment, water reuse, renewable energy