Pulp mill process closure: a review of global technology developments and mill experiences in the 1990s

Abstract

The impact of effluent discharges continues to be an important issue for the pulp manufacturing industry. Considerable progress has been made in pollution prevention to minimize waste generation, so-called manufacturing "process closure." Since the mid-1980s many important technologies have been developed and implemented, many of these in response to organochlorine concerns. Zero effluent operation is now a reality for a few bleached chemi-thermomechanical pulp (BCTMP) pulp mills. In kraft pulp manufacturing, important developments include widespread adoption of new cooking techniques, oxygen delignification, closed screening, improved process control, new bleaching methods, and systems that minimize pulping liquor losses. Coupled to this is a commitment to reduce water use and maximize reuse of in-mill process streams. Some companies pursued bleach plant closure, and many have been successful in eliminating a portion of their bleaching wastewaters. However, the difficulties inherent in closing bleach plants are considerable. For many mills the optimal solution has been found to be a high degree of closure coupled with external biological treatment of the remaining process effluent. No bleach plants at papergrade bleached kraft mills are known to be operating effluent-free on a continuous basis. This paper reviews the important worldwide technological developments and mill experiences in the 1990s that were focused on minimizing environmental impacts of pulp manufacturing operations.

Overview of Analytical Procedures for Fatty and Resin Acids in the Papermaking Process

“…The importance of analyzing wood extractives in wastewaters and receiving effluent arises in closed water circulations (Stratton et al 2004;Gavrilescu et al 2008). A variety of studies have been conducted concerning wastewater treatment in the pulp and paper industry (Ali and Sreekrishnan 2001;Pokhrel and Viraraghavan 2004).…”

Pulp Mill Wastewater: Characteristics and Treatment

“…The bleach plant is the most important source of effluent within a pulp mill and the chlorinated effluents are more complicated to reutilize within the mill. For this reason, an important trend in bleaching development is to reduce volumes and decrease the effluent loads, especially of chlorinated compounds [40][41][42].…”

Wastewater Treatment and Reclamation: A Review of Pulp and Paper Industry Practices and Opportunities

“…These approaches address not only the treatment of such effluent, but also reducing its amount by implementing strategic changes to the operations within P&P mills. Wastewater treatment systems have commonly been understood to function as "end-of-pipe" solutions to environmental issues, whereas the least expensive way to treat polluted water may be to produce less of it in the first place (Stratton et al 2004;Hossain and Ismail 2015). Unit operations within P&P mill water treatment systems have been reported before and can be mentioned here (European Commission 2001;Demel et al 2003).…”

“…Furthermore, this stage will reduce the load of bleaching plant pollutants entering the biological wastewater treatment system. Hence, such a process can reduce the loading of organic material that otherwise would be released from the pulp during bleaching of a kraft pulp (Hammar and Rydholm 1972;Stratton et al 2004). Oxygen delignification tends to be less selective than some other options, such as using chlorine dioxide.…”