Pulp & Paper International

August 2003 - ECF BLEACHING

It dominates world bleached pulp production

ECF is on a Roll!

By Douglas Pryke

Elemental Chlorine-Free (ECF) pulp, bleached with chlorine dioxide, continues to grow and now dominates the world bleached chemical pulp market. Demand for ECF increased dramatically over the last decade. In 2001, ECF held the highest worldwide market share for bleached chemical pulp at greater than 75 percent, or more than 63 million tonnes.

Market data show ECF production grew 17% in 2001. In contrast, Totally Chlorine-Free (TCF) pulp production declined slightly, maintaining a small niche market at just over 5% of world bleached chemical pulp production.

The transition to ECF is essentially complete in the US and Canada as ECF production now represents 96% of North American bleached chemical pulp production. Other regions are well on their way to replacing pulps bleached with molecular chlorine with ECF as shown in Figure 2. TCF production in these regions is negligible.

Fig. 1 - World Bleached Chemical Pulp Production: 1990-2001

World Bleached Chemical Pulp Production: 1990-2001

This trend will continue as new mills planned in Germany, Chile, Brazil, and Asia incorporate ECF bleaching [1].

Compatibility with sustainability

Over the last decade, field studies, research and chemical analysis have demonstrated that treated wastewater from well-managed pulp and paper mills using ECF bleaching is virtually free of dioxin and persistent bioaccumulative toxic substances. The remaining chlorine containing organic substances resulting from ECF bleaching have a composition similar to those found in nature, degrade naturally and do not persist in the environment. Research shows they present a negligible environmental risk to aquatic ecosystems [2].

This research has been confirmed in eco-system simulations comparing wastewaters from ECF bleaching with other non-chlorine bleaching concepts, including TCF. These investigations have reached a common conclusion [3,4]:

Fig. 2 - Growth of ECF: 1990-2002

Fig. 2 - Growth of ECF: 1990-2002

"Studies comparing ECF and TCF effluents confirmed the absence of significant differences in biological effects in the aquatic environment," says the Institute for Papermaking, Darmstadt Technical University, Germany.

Minimum Impact-Manufacturing

The vision of Minimum Impact-Manufacturing has captured the imaginations of industry and the environmental community alike. A minimum impact pulp and paper mill [5]:

• Maximizes wood yield
• Makes high quality paper that is easily recycled
• Maximizes energy production from biomass
• Minimizes water consumption, solid waste and air emissions
• Treats and disposes of waste optimally; and
• Creates sustainable value to society.

ECF is integral to achieving the vision of minimum impact. For example, pulping and bleaching strategies incorporating ECF produce strong softwood fibers, minimizing the reinforcing fiber requirements for many paper grades such as lightweight coated (LWC) [6,7].

It has also been recognized that in combination with enhanced pulping, ECF manufacturing has a higher yield, using the least amount of wood compared with other pulping and bleaching techniques [8]. Finally, ECF is compatible with, and at the leading edge of, so-called ‘closed loop’ strategies for minimizing wastewater from bleaching. Along with efficient wastewater treatment, closed loop strategies are providing optimal solutions for protecting and sustaining the receiving water ecosystem [9].

Proven pollution prevention

It is agreed that pollution prevention means more than stopping pollutants from entering the eco-system or end-of-pipe clean up after the fact. Pollution control and waste management fall short of true prevention - stopping pollution before it starts.

The well-documented problem of dioxin elimination is a case in point. Once trace levels of dioxin, an inadvertent by-product of the prevailing pulp bleaching process in the late 1980s, were discovered in the water and fish downstream of pulp and paper mills, the international industry moved quickly to voluntarily implement a comprehensive, multi-faceted strategy to eliminate these persistent, bio-accumulative toxic substances. The key component of the successful pollution prevention strategy was ECF bleaching. Worldwide experience shows papermakers have virtually eliminated dioxin discharges [10-14].

Fig. 3 - Canadian Bleached Chemical Pulp and Paper Mills: Elimination of Dioxin to Waterways

Fig. 3 - Canadian Bleached Chemical Pulp and Paper Mills

"A notable accomplishment occurred when the pulp and paper industry changed its process for pulp bleaching by substituting chlorine dioxide for elemental chlorine. This substitution virtually eliminated the production of dioxins from pulp and paper mills," notes the International Joint Commission.

"In western Europe, mills stopped the use of molecular chlorine for bleaching of pulp [i.e. implemented ECF bleaching]. This means the formation of chlorinated dioxins and furans has virtually ceased," says the European Commission.

Best available technology

During the 1990s, governments, responding to the environmental concerns posed by persistent, bio-accumulative, and toxic compounds, developed new regulations for their respective pulp and paper industries. A common feature of many of these regulations and guidelines is the concept of ‘best available technology’ (BAT).

Recognizing excellent performance, the US and the European Commission developed pulp and paper guidelines and regulations based on ECF bleaching as a core component of BAT [8,14]. These regulations and guidelines ensure compliance with the International Stockholm Convention on Persistent Organic Pollutants, the so-called POPs Treaty [15].

"We were especially pleased that the 'best available technology' selected for the papergrade kraft mills was an Elemental Chlorine-Free Technology," comments Carol Browner, former US EPA Administrator [16].

The road to sustainable ecosystem recovery

The virtual elimination of dioxin has been a key contributor to the sustainable recovery of affected aquatic ecosystems throughout the world. Fish consumption advisories downstream of pulp and paper mills are rapidly disappearing [17,18].

Fig. 4 - Lifting of Fish Consumption Dioxin Advisories Downstream of US Pulp and Paper Mills

Fig. 4 - Lifting of Fish Consumption Dioxin Advisories Downstream of US Pulp and Paper Mills

Since 1990, state authorities in the US have lifted dioxin advisories from 25 ecosystems downstream of pulp mills, representing 83% of the 30 such advisories in effect in 1990. In 2003, only 10 ecosystems remain with a dioxin advisory downstream of a bleached pulp and paper mill in the US. The Environmental Protection Agency predicts that over time all remaining dioxin advisories downstream of US mills should be lifted following conversion to ECF bleaching [19].

The final word

ECF bleaching based on chlorine dioxide is a technology choice for sustainable pulp and paper manufacturing. Papermakers and paper users alike desire ECF's excellent product quality, resource conservation attributes and compatibility with sustainable Minimum Impact-Manufacturing.

Government organizations increasingly recognize and document ECF's proven pollution prevention record, its contribution to sustainable ecosystem recovery, and its position as a core component of BAT.

Fueled by continued strong government support and proven environmental integrity, new paper mills throughout the world are incorporating ECF-based bleaching to produce quality products with sustainable manufacturing technologies.

Douglas Pryke is executive director of the Alliance for Environmental Technology (AET). For more information visit: www.aet.org

    References
  1. Trends in World Bleached Chemical Pulp Production: 1990-2001. Alliance for Environmental Technology. January 2002.
  2. BRIGHT, D., HODSON, P., LEHTINEN, K-J., McKAGUE, B., RODGERS, J. AND SOLOMON, K. Evaluation of Ecological Risks Associated with the Use of Chlorine Dioxide for the Bleaching of Pulp: Scientific Progress Since 1993. In Environmental Impacts of Pulp and Paper Waste Streams, Stuthridge, T., van den Hueval, M.R., Marvin, N.A., Slade, A.H. and Gifford, J. (Ed). SETAC Press, 2003.
  3. HAMM, U. and GOTTSHING, L. ECF- and TCF Bleached Pulps: A Comparison of their Environmental Impact. German Pulp and Paper Association VDP - INFOR project (No. 19), 2002.
  4. TANA, J. and LEHTINEN, K-J. The Aquatic Environmental Impact of Pulping and Bleaching Operations - An Overview. Finnish Environmental Agency, Helsinki, (1996).
  5. AXEGÅRD P., CAREY, J., FOLKE, J., GLEADOW, P., GULLICHSEN, J., PRYKE, D.C., REEVE, D.W., SWAN, B. AND ULOTH, V., Minimum-Impact Mills: Issues and Challenges. In Environmental Impacts of Pulp and Paper Waste Streams, Stuthridge, T., van den Hueval, M.R., Marvin, N.A., Slade, A.H. and Gifford, J. (Ed). SETAC Press, 2003.
  6. RENNEL, J., Nordic Pulp and Paper Research Journal, No. 1, 1995, p. 32.
  7. BRADLEY, M., Why Would Pulp and Paper Makers Consider Integrating Life-Cycle Assessment Into Their Businesses. 1998 PAPTAC Annual Meeting. Montreal, Quebec.
  8. European Commission. Integrated Pollution Prevention and Control (IPPC) Reference Document on Best Available Techniques in the Pulp and Paper Industry. July 2000.
  9. STRATTON, S. C. and GLEADOW, P. Pulp Mill Process Closure: A Review of Global Technology Developments and Mill Experiences in the 1990s. NCASI Technical Bulletin No. 860. May 2003.
  10. Environment Canada and Federal and Provincial Task Force on Dioxins and Furans. Dioxins and Furans and Hexachlorobenzene Inventory of Releases. A report prepared for the Federal-Provincial Advisory Committee for the Canadian Environmental Protection Act (CEPA-FPAC). January 1999.
  11. 1996 NCASI Dioxin Profile. Progress in Reducing the TCDD/TCDF Content of Effluents, Pulps, and Wastewater Treatment Sludges from the Manufacturing of Bleached Chemical Pulp. Special Report 97-04. May 1997.
  12. U.S. EPA 2000 TRI Emissions Report.
  13. International Joint Commission (IJC). 10th Biennial Report on Great Lakes Water Quality. July, 2000.
  14. Federal Register, Vol. 63, No. 72. April 1998.
  15. Stockholm Convention on Persistent Organic Pollutants. Stockholm, Sweden. May 2001.
  16. BROWNER, C., The Cluster Rule: A Step Forward. Paper Age, July 1994, p. 20.
  17. EPA May 2002. Update: National Listing of Fish and Wildlife Consumption Advisories, Fact Sheet. U.S. Environmental Protection Agency, Office of Water. EPA-823-F-02-007.
  18. Eco-System Recovery: Lifting of Fish Consumption Advisories for Dioxin Downstream of US Pulp Mills - 2002 Update. Alliance for Environmental Technology, Washington D.C. (2002).
  19. Regulatory Impact of Proposed Effluent Guidelines and NESHAP for the Pulp, Paper, and Paperboard Industry. U.S. Environmental Protection Agency, Office of Water Regulations and Standards. November 1993.