Eco-benefits assessment on urban industrial symbiosis based on material flows analysis and emergy evaluation approach: A case of Liuzhou city, China
Chinese government promotes ecological civilization in the “13th five year planning” (2016–2020) period. As a result, ecological impacts become highlight in the national circular economy practices. To apply the eco-industrial development strategy to address the intertwined industrial and regional economic development, as well as related environmental and ecological challenges is key point. Urban industrial symbiosis provides a novel approach to realize the above expectation. Traditional evaluation on circular economy provided critical environmental insights, while to date, ecological evaluation has been rather few for urban industrial symbiosis promotion. With this circumstance, this paper developed an integrated material flows analysis (MFA) and emergy evaluation model to investigate the environmental and ecological benefits of urban industrial symbiosis implementation in one typical industrial city in China. Local oriented urban industrial symbiosis network was analyzed. Inter flows and related environmental benefits of symbiotic network were quantified with MFA, and further ecological impacts were evaluated with emergy approach and the designed emergy index. From the environmental perspective, results highlighted, in general, urban industrial symbiosis generated significant life cycle environmental benefits, especially the reduction of upstream resource mining and downstream waste disposal within the regional metabolism. In total, around 204.7 million tons ore mining, 6.9 million ton solid waste and 2.3 million tons CO2 emissions were reduced per year. From the ecological perspective, total emergy input was reduced by 1.3×1022 sej, which reflected the reduction of ecological burden. Particularly, as a key indicator for ecological lost caused by pollution, dilution emergy was decreased by 2.5×1016 sej, resulting from carbon mitigation co-benefit of urban industrial symbiosis. This paper provided modeling approach to understand the ecological benefits and trade-offs of circular economy practices, and critical insights on regional eco-industrial development. It will shed a light on ecological civilization construction in China in the new national planning period.