Life Cycle Assessment On Treatment Systems Of Paper-making Wastewater

In recent years with the rapid development of China's national economy, the demand of paper was growing fast. Pulping paper making began to play an important role in the development of national economy, however, from the environmental point of view, especially water pollution situation aroused widespread interest and attention of national authorities. The traditional evaluation and selection of wastewater treatment process often uses technology - economic comparison method, but these methods can not fully consider the environmental impacts of different options. The Life Cycle Assessment (LCA) is one kind of complete management tools.On the one hand, it can evaluate wastewater treatment of environmental pollution and ecological impacts. On the other hand, it can consider resources and energy consumption levels of facilities. Finally it will link resource consumption and pollution emission to global environmental issues in order to get the advantages and disadvantages of the treatment system.The new wastewater treatment system with the original one in the Stora Enso Suzhou Paper Co.,Ltd. was compared in this study. The boundary of the study included the construction phase of wastewater treatment facilities, operation phase and the demolition phase. Inventory data in those stages of the systems were integrated with a functional unit. The impact assessment was carried out using AIST-LCA Ver4 to get the Eco-index Yen. The results showed that the Eco-index after using ultrafiltration and original treatment process were 1.40 Yen and 1.15 Yen, respectively. So impact assessment after using ultrafiltration was less than the original ones and a big portion of the difference was caused by the production and usage of PAC. And the main environment impact paths of treatment systems of paper-making wastewater were urban air pollution, global warming, solid waste and resource consumption.It was shown that the results of the study can find a way to reduce emissions of pollutants in paper-making system and provide information for selecting the paper-making wastewater treatment system with minimum environmental impact. And it will help the paper industry to make their environmental policies.