An optimized resource supply network for sustainable agricultural greenhouses: A circular economy approach

In light of the ever-increasing demand on food products and the associated intensification of agricultural activities, the environment and natural capital are witnessing unprecedented pressures. Alleviating these stresses will require the deployment of more sustainable and resilient food systems that offer a cost efficient and environmentally friendly alternatives to the conventional energy and water intensive food technologies. Greenhouses represent a promising solution to accommodate sustainable food supplies despite uncooperative external climate conditions. However, conventional greenhouses continue to rely on resource inflows originating from unstainable practices and systems such as groundwater abstraction and energy intensive production of fertilisers. Circular economy represents an opportunity to enhance resources utilisation and mitigate environmental burdens associated with their intensive exploitation at competitive costs through deploying novel solutions. In this study, waste integration involving CO₂ enrichment and sequestration along with wastewater reuse in irrigation are investigated for tomato cultivation in a greenhouse system in the State of Qatar. In this regard, a multi-objective optimisation model based on a mixed-integer linear program (MILP) is proposed to determine the optimal technology configuration and supply network that delivers resources for a greenhouse operation. The purpose of this framework is to minimise water and carbon footprints in addition to the total costs associated with resource provision to the greenhouse. Considering results from the pareto front, the optimal distribution requires 54,3579 $/year and generates around 20,043 kg of CO_2eq/year. This option suggests a sustainable cultivation alternative attributed to its environmental efficiency with regards to water savings, CO₂ offsetting, and fertiliser use reduction.