Section 8.5: Industrial symbiosis

8.4.1: Industrial Symbiosis

The decoupling of excessive resource use from economic growth is one of the central challenges that businesses face in adapting operations towards embracing a sustainable future. As we have seen throughout the unit so far, numerous strategies have been developed to assist business reduce their waste, manage the environmental consequences of their actions, and minimize their strain on the world’s remaining natural resources. One such approach, Industrial Symbiosis is based on the old saying ‘one man’s waste is another man’s treasure’.

Industrial Ecology and Industrial Symbiosis

Industrial Ecology – A question of what should we do
Industrial ecology is a broad, systemic and cross-industrial approach. It views human and industrial processes from a systems-based perspective. It visualizes and studies industrial operations and systems as ecosystems that encompass a network of processes and flows, includes industry’s wider links to society, and its impacts.

Industrial Symbiosis – A question of what and how can we do
Industrial symbiosis is a part of industrial ecology that concerns itself with the interaction and utilization of processes and flows within the industrial ecosystem. These involve processes such as recycling of residues, recovery of useful materials, and the identification of opportunities for mutually beneficial and environmentally friendly collaborative working relationships within a network of partners.

In simple terms, Industrial symbiosis is a resource efficiency approach where the unused, residual resources, or by-products (materials, energy, water, wastes, assets, logistics, and expertise), of an operation are made readily available inputs to production for another user. The figure below is a visual representation of some industrial symbiosis network processes and flows in the Netherlands.

Source: Linkoping University

Industrial symbiosis is a strategic systems-based approach, that enables traditionally separate entities from different sectors to come together collectively to identify new mutually beneficial business opportunities, efficiently retaining resources within the economy in a continuous production cycle that minimizes and avoids wastage. In short, it is a mini circular economy in action. The figure below highlights the closed-loop processes engaged within an industrial symbiosis process.


The value of Industrial Symbiosis

Working together within a network, companies can gain competitive advantage through the exchange of materials, resources, or the shared use of assets, logistics and expertise. In this way, they can increase operational efficiency, save money and reduce their environmental impact. In addition to achieving ‘green growth’, businesses participating in Industrial symbiosis networks can seize the opportunity to share knowledge, optimize supply chains, foster eco-innovation and effect long-term culture changes.

8.4.2: Industrial Symbiosis in practice

One of the earliest and best-known eco-industrial parks is located in Kalundborg, Denmark. In Kalundborg, industrial companies buy, sell and exchange waste and resources with each other in a closed cycle of industrial production.

Rather than the result of a carefully planned process, the eco-park developed gradually through co-operation by a number of neighbouring industrial companies. The main participating companies are a coal-fired power plant (Asnæsværket), a refinery (EquiNor, former Statoil), a pharmaceutical and industrial enzyme plant (Novo Nordisk and Novozymes), a plasterboard factory (Gyproc), a soil remediation company (AS Bioteknisk Jordrens), and the municipality of Kalundborg through the town’s heating facility.

The eco-park was initiated when Gyproc located its facility in Kalundborg in 1970 to take advantage of the butane gas available from the EquiNor refinery. This also enabled EquiNor to stop flaring butane gas. Since then, the network has grown, and the participating companies are now highly integrated. For instance, surplus heat from the power plant is used to heat about 4,500 private homes and water for fish farming, and fly ash is supplied for cement production. Process sludge from fish farming is supplied to nearby farms as fertilizer. Novo Nordisk also supplies farms with surplus yeast from insulin production for pig food. The EquiNor refinery supplies pure liquid sulphur from its de-sulphurization operations to a sulphuric acid producer (Kemira).

These exchanges are only part of the material flow of the Kalundborg eco-park, which has been estimated at a total of around 2.9 million tonnes a year including fuel gases, sludge, fly ash, steam, water, sulphur and gypsum. In addition to significant economic savings and reduced environmental impacts, industrial symbiosis has led companies to identify beneficial collaborations with companies and partners that they would conventionally not have any interaction with.

Watch this video for an insight into the Kadalundborg Industrial Symbiosis operation: “Kadalundborg Symbiosis”

Value Creation in Industrial Symbiosis

Economic Cas
Participants save money in two ways: they have less waste to dispose of, or they receive cheaper energy or raw materials for production. A loose estimate of the total savings in the system is 600 million Danish kroner/annum. Prices of energy and raw materials fluctuate considerably, so do fees for handling waste or regulatory demands for recycling. The recycling and material recovery systems in place within the network makes companies less volatile towards these rising prices.

Environmental and Social Benefits
The local community benefits from the improved competitiveness of its local industry, which creates additional job opportunities. In addition, having a world-renowned project in town makes it easier to retain and attract talent. For society as a whole, the environmental benefits of adopting a more circular approach to manufacturing are plenty.

– Yearly CO2 emission reduced by 240.000 tons.
– 3 million cubic meters of water saved through recycling and reuse.
– 30.000 tons of straw converted to 5.4 million liters of ethanol.
– 150.000 tons of gypsum from de-sulphurization of flue gas replaced imported natural gypsum.

The diagram below shows the evolution of Kadalundborg Symbiosis over time.

Source: Linkoping University

Supplementary Resources

Fischhoff (2017) “Cash for Industrial Trash”  

Childress (2017) “Lessons from China’s industrial symbiosis leadership”

Wolf (2007) “Industrial symbiosis in the Swedish forest industry”

Reuters (2015) “In Danish trial of “Symbiosis”, one business’ waste is another’s gold

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