Uncovering the benefits of integrating industrial symbiosis and urban symbiosis targeting a resource-dependent city: A case study of Yongcheng, China

While promoting the economic development of resource-dependent cities, the industry also brings serious environmental and ecological issues. The combination of industrial symbiosis and urban symbiosis (IS/UrS) offers a new solution to environmental and ecological challenges for resource-dependent cities. To quantify the benefits of IS/UrS in resource-dependent cities, this study assessed triple benefits including environmental (raw materials saving and wastes reuse), reduced CO2 emission, and ecological (emergy saving) benefits via IS/UrS in Yongcheng (China) by combining material flow analysis and emergy analysis. The results indicate that a total of thirty-nine IS/UrS activities (including twenty-nine in-use and ten potential IS/UrS activities) are identified, which can achieve remarkable resources saving including 2.37 Mt slag substitution for feedstock mix in cement clinker production (96% from existing in-use activities), 0.43 Mt municipal solid waste reduction (100% from potential activities), 1.07 Mt coal saving (35% from potential activities), 4.88 Mt CO2 emission reduction (23% from potential activities) and 5.53E+21 sej emergy saving (17% from potential activities). Urban symbiosis activities can contribute additional CO2 reduction and emergy saving by 11% and 7% respectively. Based on the performance of CO2 reduction and emergy saving, recycling of slag/fly ash and scrap steel should be given top priority in the local IS/UrS policy making process. The case study shows that IS/UrS is a useful approach to facilitate the sustainable development of resource-dependent cities, and could be expanded to other similar cities. (C) 2020 Elsevier Ltd. All rights reserved.