Substance flow analysis (SFA) is a kind of quantitative analysis on the metabolism of industrial process. This paper analyzed the metabolism route of copper, the main contaminant of PCB industry from the aspect of enterprise, in the manufacturing of PCBs, calculated the flux of copper between all the nodes, and studied the efficiency of copper in order to improve it. As shown from this paper, the relatively low efficiency of copper usage resulted in the copper contamination of PCB industry, which was often emitted into the environment as etching waste liquid or solid waste. Therefore, this paper proposed that we should regard the improvement of the efficiency of copper usage as key to cut off copper contamination in PCB industry, namely the focus on cleaner production with recycling of copper wastes.

The article proposes the methods to construct the commercial age of enterprises in eco-industrial parks by taking the concept of commercial age as a starting point. With Xishan Eco-industrial Park as an example, it also carries out an empirical study by selecting three enterprises from each of the three representative industries. The research results show that the enterprise age as a representative indicator reflects the characteristics of the development of eco-industrial parks and the changes of the eco-industrial structures. In this way, it will provide theoretical and practical guidance for reasonable construction of commercial age structure while maintaining the industry chain of eco-industrial park and the industrial ecosystem stability.