Industrial symbiosis is part of a new field called industrial ecology. Industrial ecology is principally concerned with the flow of materials and energy through systems at different scales, from products to factories and up to national and global levels. Industrial symbiosis focuses on these flows through networks of businesses and other organizations in local and regional economies as a means of approaching ecologically sustainable industrial development. Industrial symbiosis engages traditionally separate industries in a collective approach to competitive advantage involving physical exchange of materials, energy, water, and/or by-products. The keys to industrial symbiosis are collaboration and the synergistic possibilities offered by geographic proximity.
The term 'industrial symbiosis' was coined in the small municipality of Kalundborg, Denmark, where a well-developed network of dense firm interactions was encountered. The primary partners in Kalundborg, including an oil refinery, a power station, a gypsum board facility, and a pharmaceutical company, share ground water, surface water, wastewater, steam, and fuel, and they also exchange a variety of by-products that become feedstocks in other processes. High levels of environmental and economic efficiency have been achieved, leading to many other less tangible benefits involving personnel, equipment, and information sharing. Many other examples of industrial symbiosis exist around the world and illustrate how the concept is applied.
This article provides definitions of industrial symbiosis and related terms and discusses many elements of industrial symbiosis such as energy and water cascading, cogeneration, and materials exchange. It examines tools such as input/output matching, stakeholder processes, and materials tracking. The article discusses how industrial symbiosis is a useful umbrella term because it can describe exchanges across entities regardless of whether they are colocated, located near one another but not contiguous, or located within a broader spatial area such as regionally. It also examines technical and regulatory considerations that have come into play in various locations that can facilitate or inhibit industrial symbiosis. Finally, it considers future directions with regard to industrial symbiosis based on historical and current experience.
Definition of industrial symbiosis and related terms
The term 'symbiosis' builds on the notion of mutualism in biological communities where at least two otherwise unrelated species exchange materials, energy, or information in a mutually beneficial manner. So, too, industrial symbiosis consists of place-based exchanges among different entities that yield a collective benefit greater than the sum of individual benefits that could be achieved by acting alone. Such collaboration can also increase social capital among the participants. As described in what follows, the symbioses need not occur within the strict boundaries of a park, despite the popular use of the term 'eco-industrial park' to describe organizations engaging in exchanges.
At the same time interest began to develop in industrial symbiosis and eco-industrial parks, a number of other parallel tracks advanced that might be construed, broadly, as green development. These include residential, commercial, industrial, and community development as captured in terms such as sustainable architecture, green buildings, sustainable communities, and smart growth. Eco-industrial development or sustainable industrial development narrows down the possibilities to refer predominantly to industrial and commercial activities and, increasingly, agriculture. Cooperating businesses that include a materials/water/energy exchange or sharing component qualify the activity as industrial symbiosis.
There are three primary opportunities for resource exchange: 1) By-product reuse - the exchange of firm-specific materials between two or more parties for use as substitutes for commercial products or raw materials. The materials exchange component has also been referred to as a by-product exchange, by-product synergy, or waste exchange and may also be referred to as an industrial recycling network. 2) Utility/infrastructure sharing - the pooled use and management of commonly used resources such as energy, water, and wastewater. 3) Joint provision of services - meeting common needs across firms for ancillary activities such as fire suppression, transportation, and food provision.
As with the term 'industrial park', the term 'eco-industrial park' refers to eco-industrial development on a particular plot of real estate. An eco-industrial park may include many ecologically desirable goals, including mechanisms to reduce overall environmental impact, conserve materials and energy, and foster cooperative approaches to resource efficiency and environmental management. The terms 'industrial estate' and 'eco-industrial estate' are more commonly used in Asia and can include communities of workers who live in or near the group of businesses constituting the industrial estate. Gunther Pauli popularized a similar notion , zero-emissions parks, to emphasize the drive toward sustainable industrial development. The agricultural community has found that while traditional agriculture incorporated cyclical reuse of by-products, industrial agriculture became much more linear, consuming materials and disposing of wastes. Therefore, many zero-emissions researchers describe integrated biosystems in which at least two biological subsystems are part of an integrated process to reduce emissions and reuse agricultural by-products.
Some writers refer to eco-industrial networks to capture a broad range of environmental and economic activities among businesses. Just as economic clusters have come to mean a group of businesses that are sectorally related by the products they make and use, such as the furniture cluster in central North Carolina in th USA, the term 'eco-industrial clusters' is sometimes used to describe environmental interactions among firms in the same or related industries. Industrial complexes of sectorally-related firms have been successful for the past several decades in overall pollution reduction in industries such as pulp and paper, sugarcane, textiles, and plastics.
Although materials and energy exchanges have been a significant part of industry for centuries, focus on environmental attributes is much more recent. In a foundational 1989 article on industrial ecology, Frosch and Gallopoulos described the underlying notion of an ‘‘industrial ecosystem’’ in which ‘‘the consumption of energy and materials is optimized and the effluents of one process may serve as the raw materials for another process.’’ Others have extended the ecosystem metaphor to see related industrial activities as a food web and to interpret the roles of various scrap and remanufacturing businesses as the scavengers and decomposers of these systems.
In any multidisciplinary field such as industrial ecology, there are strands from many disciplines and paths of research that are the antecedents of current understanding. Industrial symbiosis was not popularized, however, until the first articles and analyses of the industrial region in Kalundborg were published during the early 1990s. One origin of industrial symbiosis is from the chemical industry, which embeds an intrinsic value chain of materials as they are degraded. Other terms discussed previously originate in ecology, agricultural studies, engineering, economic geography and/or business economics. Cogeneration and utility sharing have been justified on engineering, environmental, and economic grounds. Indeed, private industry sees cost efficiency as a driving factor in stimulating these relationships, whereas city planners, economic development experts, and real estate developers also emphasize land use, social and environmental aspects, and the synergies that can arise from colocation.
Kalundborg and Self-Organizing Symbioses
The model of industrial symbiosis was first fully realized in the industrial district in Kalundborg. Although it is continually evolving, there are currently some 20 exchanges occurring among the symbiosis participants involving water, energy, and a wide variety of residue materials that become feedstocks in other processes.
Figure 1 shows the interrelationships of the symbiosis participants. Each exchange was developed as an economically attractive business arrangement between participating firms through bilateral contracts. It is significant to mention that this symbiosis was not based on a planning process and that it continually evolves. Regulation has played an indirect role over the years; for example, the national ban in Denmark on placing organic waste streams into landfills caused the pharmaceutical company to seek arrangements to apply its sludges on agricultural lands. Social cohesion is regularly cited as a key element of success in the Kalundborg symbiosis.
Rather than a static system of locked-in firms and technologies as was feared by some skeptics of industrial symbiosis, individual participants in the symbiosis have changed significantly over time, and the ecosystem as a whole has adapted. Over the past several years, Kalundborg’s Statoil Refinery doubled its capacity based on North Sea claims, the Asnæs Power Station switched from coal to orimulsion to comply with mandated carbon dioxide (CO2) reduction and later switched back to coal. The pharmaceutical plant split into two ventures, eliminated some product lines (including penicillin), and increased others. Rather than tie themselves to a single supplier, the symbiosis participants try to insulate themselves from supplier interruptions by diversifying sources to reduce business risk, just as in traditional supplier–customer relationships. Although each individual business change alters the makeup of the industrial ecosystem, the changes collectively have not diminished the overall nature of the symbiosis.
Analysis of Kalundborg as a self-organizing, spontaneous system contrasts with the attempt to build new eco-industrial parks from scratch. Recent research highlights the desirability of working from an established past, particularly where private companies began exchanges on their own for business reasons; from these "kernels" of symbiosis coordination can lead to gradual growth interactions. In contrast with planned eco-industrial parks, the spontaneous ones are proving to be more robust and resilient to market dynamics.
Elements and tools of industrial symbiosis
Drawing on industrial ecology, industrial symbiosis incorporates many elements that emphasize the cycling and reuse of materials in a broader systems perspective. A brief discussion of several elements is presented, followed by a discussion of useful analytical tools for industrial symbiosis. These elements include embedded energy and materials, a life cycle perspective, cascading, loop closing, and tracking material flows.
Embedded Energy and Materials
To create a product, resources are used for extraction of materials, transportation, primary and secondary manufacturing, and distribution. The total energy and materials used is the amount embedded in that product. By reusing byproducts, industrial symbiosis preserves the embedded materials and energy for a longer period within the industrial system. Cogeneration is a specific means of utilizing embedded energy by reusing waste heat to produce electricity or by using steam from electric power generation as a source of heat.
Life Cycle Perspective
As described by Graedel and Allenby in the first textbook in the field, industrial ecology is ‘‘a systems view in which one seeks to optimize the total materials cycle from virgin material, to finished material, to component, to product, to obsolete product, and to ultimate disposal.’’ A life cycle perspective ensures a breadth of focus that is not limited to what happens within one facility or factory but rather considers the entire set of environmental impacts that occur at each stage of the product life cycle and use across entities. With respect to industrial symbiosis, a life cycle perspective is helpful in assessing symbiotic opportunities—the junctures in the product life cycle at which the byproduct of concern can be considered for another use.
Cascading occurs when a resource, such as water or energy, is used repeatedly in different applications. In successive uses, the resource is of lower quality, a lower level of refinement, and/or lower value. By definition, a cascade must include at least one use beyond the virgin use of the resource and is generally conceptualized as a downward step diagram. The cascade terminates when either a considerable amount of energy must be added to recover value from the resource or the resource is discarded. Cascading is a common strategy for industrial symbiosis because the firm producing the used resource can save on treatment or disposal and possibly can earn compensation in exchange for the value of the resource. The environmental benefits of cascading are numerous, including the reduced use of virgin resources, the avoided impact of resource extraction, and the reduced deposition of waste into the environment.
If cascading is conceptually stepwise, loop closing is more circular. A general name for many different variations of reuse and recycling of resources, loop closing occurs when a resource has a cyclical flow embedded in the industrial ecosystem and the resource, rather than being used in a degraded form, reappears akin to its original form. Thus, glass bottles may be washed out directly and returned to use, or glass bottles may be collected and crushed into cullet before the glass cullet is melted to make new glass containers. Both methods close the loop and return the glass to a form similar to its previous form. The economic and environmental benefits of loop closing are similar to those of cascading.
Tracking Material Flows
Also key to industrial symbiosis studies is the tracking of material, water, and energy flows. This form of accounting captures instances of loop closing, cascading, and unidirectional flows. Over time, many applications of materials tracking at different scales have yielded specific tools, such as material flow analysis (MFA) and substance flow analysis (SFA), that formalize tracking practices. Materials tracking for symbiosis identifies and quantifies all significant material inputs and outputs of each firm in the subject industrial system. The results are analyzed to suggest opportunities for exchange of materials among firms as well as opportunities for more efficient resource use in the industrial ecosystem.
To the extent that new symbioses can be planned or existing exchanges can be augmented, several tools have proven to be useful in industrial symbiosis analysis. These tools are industrial inventories, input/ output matching, stakeholder processes, and materials budgeting.
Once a district has been identified as a candidate for industrial symbiosis, it is useful to begin with an inventory of local businesses and other resources, including utilities and relevant institutions. Because confidentiality is a critical aspect of dealing with private companies, data can be collected generically concerning the inputs and outputs of relevant industrial processes to achieve a base analysis from which to assess further goals.
Key to symbiosis is the matching of inputs and outputs to make links across industries. There are various ways in which to collect these data in a systematic fashion, including written and oral surveys and literature review. The U.S. Environmental Protection Agency (EPA) commissioned three pieces of input/output matching software during the late 1990s to be used as a planning tool to allow communities to investigate what mix of specific types of industries might support industrial symbiosis. FaST (Facility Synergy Tool) was a database of industry profiles describing typical inputs and outputs of specific types of facilities. It had a data input screen and a search mechanism to identify possible input/output matches among facilities. DIET (Designing Industrial Ecosystems Tool) allowed scenario analysis of various combinations of facilities. It included a linear programming optimization model to enable planners to optimize environmental, economic, and/or employment objectives and to change the relative weights of each. REaLiTy (Regulatory, Economic, and Logistics Tool) helped sort out regulatory hurdles likely to be confronted depending on the actual materials chosen for exchange.
A caveat on these and related models is that they can overemphasize idealized what-if scenarios with too little recognition of the time-consuming processes involved in attracting any business, let alone the optimal suite of symbiotic partners. It is also appropriate to add the cautionary note that most industrial products generally have not been designed for reuse, and so great care must be taken to see that the proposed match across systems is sound with respect to regulation and integration of best practices. New modeling approaches emphasize capturing knowledge throughout the industrial symbiosis development cycle, such that lessons learned identifying opportunities, overcoming barriers, and commercializing synergies, can be documented and leveraged toward future development.
To the extent that industrial symbiosis involves different layers of unconnected participants, a broad array of community involvement techniques is warranted. In the USA, both the Londonderry Eco-Industrial Park in New Hampshire and the Sustainable Industry Park in Cape Charles, Virginia, assembled many diverse stakeholders and then conducted design charettes to seek input about what an eco-industrial project should look like in the local context. Whether and how to pursue specific covenants or conditions as a type of deed restriction is one topic of stakeholder meetings. Applied Sustainability gathered experience convening stakeholders from business and government in its efforts to create by-product synergy in Tampico, Mexico, and Alberta, Canada. The National Industrial Symbiosis Programme (NISP) in the United Kingdom provides brokerage services, linking companies with potential synergiestic matches, as well as working with national and local government bodies. Openness among participating companies and continued coordination by a stakeholder group such as an advisory council is important both to establish and to maintain the momentum of a symbiosis.
Materials budgeting, a type of materials tracking discussed previously, can be used to map energy and material flows through a chosen system. Formally, in industrial ecology, materials budgeting embraces three concepts: (1) reservoirs, where a material is stored; (2) flux, which is the amount of material entering or leaving a reservoir per unit time; and (3) sources and sinks, which are rates of input and loss of specific materials entering or leaving a system. Because it helps to identify both stocks and flows, materials budgeting can be a basic building block of an industrial symbiosis analysis. By tracking material flows, Schwarz and Steininger determined the existence of a symbiotic network in Styria, Austria, larger than that at Kalundborg.
Spatial scale of industrial symbiosis
In general, industrial symbiosis occurs locally or regionally across participating companies. Increasing the distance among firms lessens the breadth of exchange opportunities because it is not cost-effective to transport water and steam beyond regional boundaries, whereas byproducts can often travel much farther. Observing numerous instances of industrial symbiosis, Chertow devised a taxonomy of materials exchange types to consider spatial and organizational elements. These include through waste exchanges (type 1); within a facility, firm, or organization (type 2); among firms colocated in a defined eco-industrial park (type 3); among local firms that are not colocated (type 4); and among firms organized ‘‘virtually’’ across a broader region (type 5).
Type 1: Through Waste Exchanges
Most often focused at the end-of-life stage of a product or process, examples of these exchanges would include contributions of used clothing for charity and collection of scrap metal or paper by scrap dealers or municipal recycling programs. Waste exchanges formalize trading opportunities by creating hard-copy or online lists of materials that one organization would like to dispose of and another organization might need. The scale of trades can be local, regional, national, or global. The exchanges accomplish various input/output savings on a trade-by- trade basis rather than continuously. They feature exchange of materials rather than of water or energy.
Type 2: Within a Facility, Firm, or Organization
Some kinds of materials exchange can occur primarily inside the boundaries of one organization rather than with a collection of outside parties. Large organizations often behave as if they are separate entities and may approximate a multi-firm approach to industrial symbiosis. In the context of state-owned enterprises common in Asia, material exchanges can extend along the supply chain of a product still under single ownership. The Guitang Group, a state-owned enterprise in China, expanded from sugar refining to include alcohol and paper production as a means of deriving income from the use of its own byproducts, specifically molasses and bagasse. The group was recently privatized and extended its exchange network into a community-wide one to receive byproducts of other sugar producers for increased paper production.
Type 3: Among Firms Colocated in a Defined Eco-industrial Park
In this approach, businesses and other organizations that are contiguously located can exchange energy, water, and materials and can go further to share information and services such as permitting, transportation, and marketing. Type 3 exchanges occur primarily within the defined area of an industrial park or industrial estate, but it is also common to involve other partners "over the fence." The areas can be new developments or retrofits of existing ones. The Londonderry Eco-Industrial Park was established in a green field adjacent to an industrial zone. The Industrial Estate Authority of Thailand has a plan to adopt sustainable practices at 28 industrial estates at various stages. In Canada, Burnside Industrial Park in Dartmouth, Nova Scotia, is an example of retrofitting an existing industrial park to improve environmental performance. The park is spread over 2500 acres, with more than 1200 businesses employing some 18,000 people. Côté reported that researchers from Dalhousie University have been devising principles and strategies to work within the park to encourage its transformation into an industrial ecosystem.
Type 4: Among Local Firms That Are Not Colocated
Partners in this type of exchange need not be sited adjacent to one another but rather are located within a small geographic area, as in Kalundborg, where the primary partners are within roughly a 2-mile radius of each other. Type 4 exchanges draw together existing businesses that can take advantage of already generated material, water, and energy streams and also provide the opportunity to fill in new businesses based on common service requirements and input/output matching. In the Kwinana industrial area south of Perth, Australia, heavy process industries were established beginning in the 1950s and now employ some 3600 people. Through their industrial council, the companies have resolved to develop regional synergies and have doubled the number of companies involved in exchanges over the past decade.
Type 5: Among Firms Organized Virtually across a Broader Region
Given the high cost of moving and other critical variables that enter into decisions about corporate location, very few businesses will relocate solely to engage in industrial symbiosis. Type 5 exchanges depend on virtual linkages rather than colocation. Although still place-based enterprises, type 5 exchanges encompass a regional economic community in which the potential for the identification of byproduct exchanges is greatly increased by the larger number of firms that can participate. An additional attractive feature is the potential to include small outlying agricultural and other businesses. Self-organized groups, such as the network of scrap metal dealers, agglomerators, and dismantlers that feed particular mills and subsystems (e.g., auto recycling), could also be considered as type 5 systems. Specific projects organized in the Triangle J region of North Carolina, in Tampico, and in Alberta sought to identify relevant material and energy inputs and outputs and to match companies within their regions to each other when doing so is economically and environmentally efficient. Hasler has contibuted this work in Styria, Austria.
Technical, regulatory, business, and social issues
Because industrial symbiosis requires inter-organizational cooperation, including knowledge of physical flows, this creates both barriers and opportunities beyond those of more conventional development projects. These include technical, regulatory, business and social issues.
In general, symbiotic industrial facilities need to be in close proximity to avoid large transportation costs and energy degradation during transit. High-value byproducts, such as pure sulfur from sour gas treatment, are exceptions. Industrial symbioses of types 3 and 4 usually incorporate at least one anchor tenant such as a power plant or refinery with a large, continuous by-product stream. Wastes that are predominately organic in nature (e.g., the effluent from fermentation of pharmaceuticals or brewing), as well as raw agricultural or forestry by-products, can also be attractive. Use of organic streams from fermentation as feed or fertilizer requires assurance that toxic components or organisms are absent. Materials production, such as the manufacture of wallboard, is technically challenging and requires close matching of compositions. Supply security is important to the users of by-product streams, as would be the reliability of more conventional materials suppliers located farther away. The problem of achieving sufficient scale when aggregating byproducts is significant because even if discarded materials are collected from numerous facilities, the total volume can fall far short of the raw materials necessary to support a new operation.
In Japan, scarcity of land for waste disposal has prompted significant cooperation and technological innovation to overcome technical barriers in affected industries. The Japanese cement industry now consumes approximately 6% of the country’s waste, including half of the fly ash produced by power plants. As a result, the Japanese cement industry reports the smallest energy consumption per ton of cement produced among developed countries. Taiheiyo Cement has been developing a new technology to convert plastic waste (including PVC) and other industrial wastes into raw materials and fuel. Another technology decomposes dioxin from fly ash through heating at high temperatures inside cement kilns. Heavy metals are extracted by wet-type refining technology to be recycled for the nonferrous metal industry.
Industrial symbiosis is often at odds with environmental regulatory requirements, which may preclude byproduct exchanges or at least serve as a very strong disincentive. For example, in the United States, the Resource Conservation and Recovery Act (RCRA) regulates the treatment, storage, and disposal of numerous wastes as a means of averting risks stemming from the improper management of hazardous waste. The law requires that byproducts be matched to specific mandatory protocols through a very extensive set of rules that leaves little room for innovative schemes for byproduct reuse as feedstocks elsewhere. This inflexibility is based in large part on a deep-seated fear of sham recycling, an undertaking where the generator of a waste product makes a show of reusing that byproduct merely to escape treatment requirements. Industrial symbiosis must be distinguished from such efforts if it is to continue to develop within the current regulatory system.
In many developing countries, governments lead the process for establishing industrial parks and estates. Lowe found that this can slow the development process. In addition, these projects are likely to rely on funding from development banks for which industrial symbiosis projects might seem unconventional and, thus, fall outside of development bank guidelines.
In some instances, regulatory actions encourage industrial symbiosis. Landfill bans in key European countries have driven symbiotic practices such as the reuse of organic wastes prohibited from land disposal in Denmark and the Netherlands. Very high tipping fees for waste disposal in Canada and climate change levies in the United Kingdom have been cited as stimulating innovation and action in by-product reuse.
Although private actors need not be the initiators, they clearly must be committed to the implementation of industrial symbiosis because, in most instances, the flows that make up the industrial symbiosis either belong to private actors or will be shared with them in the case of municipal wastewater linkages. Whether key private actors can appropriate sufficient benefit from environmental gains is a challenge to industrial symbiosis, especially given that the level of business benefit to various partners is not uniform. Businesses generally want to address non-product problems at the lowest cost and with the least use of resources. Such objectives might not include the time or inclination to work with others, especially concerning low-value wastes.
As a practical matter, all significant development projects take a long time, require substantial capital investment, and must constantly meet the test of whether investment in them will create sufficient returns. These issues are compounded with eco-industrial projects by the need for multi-party planning and coordination and the attendant transaction costs, including the risk that a proposed partner will relocate.
Industrial symbiosis raises the question of whether the desire to reuse waste streams comes at the expense of adhering to pollution prevention principles calling for the elimination of waste at the front end of the process. Some suspect that industrial symbiosis projects favor older dying industries and keep them going rather than fostering a new generation of clean technology. Overall, industrial symbiosis could potentially discourage companies from updating their systems, plant, and equipment, instead substituting the veil of interdependence.
At the first level of analysis, it is reasonable to assume that companies will do what is in their economic interest. If, through incremental improvements or through broader scale process redesign, a company can eliminate waste in a cost-effective manner, rational actors will do so. In this sense, pollution prevention comes first. It is plausible, however, that the opportunity for symbiosis might make the proposed process improvement fall lower in priority in a company’s capital outlay scheme, in which case the company’s own economic decision making might favor the symbiosis over pollution prevention.
Communication and trust are thought to be important factors in inter-firm cooperation. This may be even more important when the materials being exchanged have potential liabilities because they are subject to environmental regulations. Forums that facilitate inter-firm communication and collaboration are thus essential for the development of industrial symbiosis. In Kalundborg, the small size of the city and creation of the Environment Club in the 1980s facilitated regular interaction and communication among the managers in the major industries. Following the insights from Kalundborg, Ashton performed the first "social network analysis" of an industrial ecosystem in the Barceloneta pharmaceutical cluster in Puerto Rico which supported the idea that trust across firms is significant in organizing inter-firm exchanges.
Globalization, miniaturization, and resource scarcity will all play roles in the future of industrial symbiosis. As important as resource conservation in western countries, it is dramatically more important in developing countries where resources are already scarce and expansion is large and rapid. Key industrial symbiosis programs have recently begun in Chinese industrial parks with the cooperation of the State Environmental Protection Administration and the National Development and Research Council. The Resource Optimization Initiative of India has found the systems approach of industrial ecology critical to understanding the potential of inter-firm and inter-farm sharing. That industrial symbiosis mitigates some global warming impacts is becoming clearer, emphasizing that cycling of water, energy and materials conserves freshwater, reduces fossil fuel consumption, and eases long distance material transport.
Conceivably, the private sector could grab hold of industrial symbiosis as a means of increasing resource availability and security. It is also a logical extension of concepts such as resource productivity promoted by the World Business Council for Sustainable Development and its affiliates. Governments could latch onto eco-industrial parks as another way in which to redevelop brownfields and structure new industrial developments. Hybrid public-private organizations, such as NISP, could facilitate the growth of eco-industrial networks by bridging the informational and cost barriers that face many projects. On the one hand, a public already nervous about genetic engineering may become more restive about material exchanges that bring one industry’s residues to an altogether different industry. On the other hand, region-specific water shortages and the scarcity of some materials accelerate the trend toward cycling and reuse.
Variety and experimentation in industrial symbiosis developments around the world will shed light on what is and is not successful, what the largest risks are, how regulatory hurdles can be overcome, what can be financed, and what is most environmentally beneficial and technologically desirable. The form could splinter back toward specific industry clusters around key materials such as plastics or around wastes such as in recycling parks. Increasingly, technologies may embed their own reuse such as the cycling of steam back into the industrial process in combined cycle power plants. It is also possible that much broader visions, which combine industrial symbiosis with other types of urban and regional planning, will prevail. The Japanese Central Government and the Ministry of Trade and Industry have designated several eco-towns to promote environmentally friendly practices such as zero emissions and material exchanges. The quest to find the most beneficial forms of resource sharing is part of the journey toward sustainable industrial development.
Content Source: Wikimedia Commons
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