Modelling and Evaluating Industrial Symbiosis in Agri-Food Networks through Advanced Simulation - Moving Towards Circular Economy in the UK

Industrial Symbiosis (IS) represents a concept in a specialised domain within the field of Industrial Ecology, with its primary objective centred on synergistic relationships among entities. These relationships encompass a tangible exchange of materials, energy, and services strategically orchestrated to yield concurrent economic and environmental advantages.

Industrial Symbiosis Network (ISN) can be viewed as complex adaptive systems where the network facilitates these symbiotic relationships, providing a framework for businesses to identify, establish, and manage resource exchanges effectively.

In Northern Ireland (NI), the dairy production and processing industry accounts for 31% of the overall gross agricultural output (DAERA, 2022). Businesses like farms, beer breweries and anaerobic digesters also play a pivotal role in NI's gross output. The significant production in these sectors also generates substantial by-products, and inadequate waste handling results in severe environmental repercussions.

For example, large discharge of farming waste is suspected to be one of the main reasons for the contamination of Lough Neagh, the largest freshwater lake in the UK, supplying 40% of NI's drinking water (BBC News, 2023). Although the industries have traditionally incorporated environmental measures, there are persistent challenges in pursuing sustainable production practices, particularly concerning the effective closure of material loops.

The literature identifies numerous applications of those by-products, which can be re-utilised for other purposes or production. For example, the use of cheese whey in milk-based soaps as replacement for raw milk and spent grains as animal feed in farms. This creates an opportunity to develop ISN comprising industries that can share or exchange resources.

While previous studies have explored advanced modelling and simulation techniques within individual industries, there is a notable scarcity of literature regarding their application to material exchange operations in an ISN context. Therefore, it is important to conduct a comprehensive analysis of the ISN model by utilising Material Flow Analysis (MFA) to track the material flows and advanced simulation to incorporate dynamic characteristics such as market and technical disruptions in the model.

This analysis becomes essential to comprehend the benefits and mitigate any potential risks in an ISN that focus on the reutilisation of by-products.

Information flow, technology and data management in the Agri-food supply chain and networks are considered key enablers for ISN. This research project aims to contribute to theory and practical application by developing an ISN model with dairy processors at its core. Based on the literature and available data, symbiotic partners considered are a beer brewery, an anaerobic digester, a soap producer and animal farms.

This network facilitates the exchange of by-products among these facilities, fostering a cooperative system of shared by-product streams. In this project, an advanced simulation model is employed to scrutinise the disruptions to ISN arising from technical and market fluctuation between different entities while assessing the associated network, economic and environmental metrics.

A regional ISN positively impacts at least four United Nations Sustainable Development Goals (UNSDG) - UNSDG 7, 9, 11, and 12. This research contributes to the literature on sustainable supply chains, operations, and the circular economy. It achieves this by modelling the ISN through MFA and simulation model to potentially benefit the participant companies by achieving better resource efficiency and sustainability goals.

Moreover, the insights derived from this study can benefit the dairy industry and its symbiotic partners, adding to their knowledge on reusing by-products, creating a new business model and unlocking additional potential advantages of symbiotic relationships.