Study On Cleaner Production And Wastewater Recycle-circulation In Recycled Papermaking Mills

The wastewater of papermaking industry is a social highlight. In recent years, because of material adjustment, the proportion of recycled papermaking mills in papermaking industry has been bigger and bigger, now are beyond 50%. Now people have taken care of the wastewater treatment in these mills. Zero discharge of wastewater achieved in recycled papermaking mills is feasible because of their low-grade pollution and easy disposal.This paper investigates the status of Cleaner Production in recycled papermaking mills, analyzes the actuality of domestic mills, and gives measures of zero discharge. These measures include:(1) Generalize Cleaner Production (CP) in mills:CP is the optimal approach to achievewastewater zero discharge. In chapter 2, based on the analysis of the production and environmental protection and the practice of Cleaner Production Audit(CPA) in recycled papermaking mills, the study analyzes the mills' potential of CP, presented tools and keys of CPA, generalizes CP technologies, and shows the obstacles in the course of implementing CPA and gives strategies and suggestions in the end.(2) Closed cycle of white water.:The white water system is most possible to implement wastewater closed recycle and zero discharge. In chapter 3, the study puts forward principles for white water closed cycle by investigating pinch technology and three steps circular system and gives measures on the basis of the principles. Besides these, presents methods to deal with the negative impacts on paper machine operating and paper quality that as a result of white water closed cycle.(3) Wastewater treatment. :Introduced the character of pulping wastewater and some different pulping wastewater treating techniques, compared their advantages and disadvantages.(4) Recycled papermaking process model assessment.:Introduced the CPA and Water Environmental Impact Assessment to Recycled papermaking process, analyed and evaluated the case history with these methods. Based on the qualitative and quantitative index gained from the assessment, we could identify the CPA level and the implementation level of wastewater closed recycle, and put forward accordingly suggestions and environment protecting measures.