Global Survey of Inter-Firm Waste Reuse in Industrial Clusters

Previous studies of inter-firm waste reuse networks (industrial symbiosis) have focused on individual clusters. We studied the sources and reuse pathways of industrial wastes within 80 industrial clusters in 19 countries. 1030 existing waste and by-product exchanges were identified through a survey of peer-reviewed journal articles. The producers and users of utilized by-products were analyzed by the North American Industry Classification System (NAICS), as well as the network structure of each cluster. We observed that waste heat utilization was the most common form of by-product exchange in the clusters studied, accounting for 16.1% of all reported waste exchange cases. Wastewater reuse, including untreated process water, reclaimed water and condensate, accounted for 14.5% of exchanges. Other commonly exchanged by-products included non-metallic minerals like coal ash and flue gas desulfurization (FGD) gypsum (8.2%) used mainly in production of construction materials, flue gas and biogas (5.6%), and sewage sludge (2.5%). Surprisingly, carbon dioxide accounted for 2.7% of all reported waste reutilization cases alone, which was delivered to greenhouses and industrial gas producers. We also observed that the production of fertilizer and animal feed from chemical and biomass wastes were significant pathways for waste reuse. Top producers (NAICS industries) of exchanged by-products were: (1) Electric Power Generation; (2) Sewage Treatment Facilities; (3) Iron and Steel Mills and Ferroalloy Manufacturing; (4) Other Basic Inorganic Chemical Manufacturing, and; (5) Petroleum Refineries. Top users of by-products were: (1) Cement Manufacturing; (2) Electric Power Generation; (3) Fertilizer Manufacturing; (4) Other Basic Inorganic Chemical Manufacturing, and; (5) Iron and Steel Mills and Ferroalloy Manufacturing.