ECF: POLLUTION PREVENTION FOR THE PULP AND PAPER INDUSTRY

Douglas C. Pryke
Alliance for Environmental Technology
RR #1
Erin, Ontario N0B 1T0
Canada

SCOPE

Elemental Chlorine-Free (ECF) bleaching for the pulp and paper industry, based on chlorine dioxide, offers a number of fundamental benefits over traditional methods. Time and time again, in both laboratory and industrial experience, chlorine dioxide has proven itself to be a pollution prevention process for the pulp and paper industry. Perhaps most important is that use of chlorine dioxide in the first stage of chemical pulp bleaching virtually eliminates the formation of dioxin and other persistent, bio-accumulative substances.

The virtual elimination of dioxin has yielded a number of environmental health benefits. Chief among these is the ongoing recovery of our nation's aquatic eco-systems, as evidenced by the liftings of fish consumption advisories for dioxin downstream of North American pulp mills.

Over the last five years, North American bleached chemical pulp mills have substantially replaced chlorine in the first stage of bleaching with chlorine dioxide. In many mills chlorine dioxide has completely replaced chlorine (also known as Elemental Chlorine-Free, or ECF, bleaching. Currently, 40% of North American bleached chemical pulp is now produced by mills that have converted to complete substitution with chlorine dioxide (ECF).

Environmental benefits will be maximized as the industry continues to convert to this "green chemistry." The U.S. Environmental Protection Agency (EPA) itself has analyzed the remaining dioxin advisories downstream of U.S. pulp mills against its Best Available Technology (BAT) criteria for bleached chemical pulp mills, based on complete replacement with chlorine dioxide. The study showed that following the implementation of new proposed guidelines, all remaining dioxin advisories downstream of pulp mills would be lifted [1].

In recognition of the superior environmental performance of chlorine dioxide, the EPA in July of 1996 issued its "Notice of Availability" for the Agency's proposed Cluster Rule for the pulp and paper industry. In the "Notice", the EPA proposed two options for Best Available Technology, both based on ECF (100 percent substitution of chlorine dioxide for chlorine).

APPLICATION

Following the identification, in the late 1980s, of trace levels of dioxin, an inadvertent by-product of the prevailing chemical pulp bleaching process, the international pulp and paper industry moved quickly and voluntarily to implement a comprehensive, multi-faceted strategy that has virtually eliminated dioxins. By applying raw material substitution, one of the principles of pollution prevention, the industry has achieved both the letter and the intent of the Pollution Prevention Act of 1990 (PPA).

The PPA recognized that, "... there are significant opportunities for industry to reduce or prevent pollution at the source through cost-effective changes in production, operation, and raw materials use...". The PPA also acknowledged that "... source reduction is fundamentally different and more desirable than waste management and pollution control...".

Though "pollution prevention" is not specifically defined, the PPA makes clear that "pollution prevention" incorporates the concepts of both preventing and reducing the formation of pollution.

The PPA defines the term "source reduction" as any practice that:

  1. reduces the amount of any hazardous substance, pollutant, or contaminant entering any waste stream or otherwise released into the environment; and

  2. reduces the hazards to public health and the environment that are associated with the release of such substances, pollutants, or contaminants [2].

As the International Joint Commission noted,

"the pulp and paper industry in the Great Lakes basin has largely completed a transition to secondary effluent treatment and the use of chlorine dioxide rather than chlorine gas in bleaching. Effluent acute toxicity effects have been largely eliminated and dioxin in effluent has been substantially reduced. The alteration in bleaching technology indicates that this industry is applying a pollution prevention rather than a pollution control approach [3]."

As indicated, key to the industry's pollution prevention success was the discovery that increased substitution of chlorine dioxide for chlorine in the first stage of chemical pulp bleaching virtually eliminated the formation of dioxin. As chlorine dioxide is increasingly substituted, dioxin formation is virtually eliminated [4].

BENEFITS

The success and environmental benefits of chlorine dioxide and its application in bleaching processes can be measured in terms of dioxin elimination and eco-system recovery.

These two measures are documented by the declining national emissions in waste waters, declining body burdens of dioxin in fish and the lifting of fish advisories for dioxin throughout North America, particularly downstream of pulp and paper mills.

In both the U.S. and Canada, fish consumption advisories have been--and continue to be--lifted as dioxin levels downstream of pulp mills decline. These indicators of progress and broader eco-system integrity demonstrate the success of the pulp and paper industry's use of chlorine dioxide as a "green chemistry."

In the U.S., fish consumption advisories are based on factors such as contamination levels of specific target chemicals, which include, among others, dioxin, mercury, PCB's (polychlorinated biphenyls), and various pesticides. As such, advisories are one indicator of the environmental status of a particular aquatic eco-system, for example a lake, bay, or river. Removing or partially rescinding a fish consumption advisory or ban generally signals positive change in the aquatic eco-system under study. Advisories are generally lifted by state officials once fish tissue levels drop and remain below state action thresholds.

An analysis of the 1996 EPA's National Listing of Fish and Wildlife Consumption Advisories, reveals that, the small number of waterbodies under a dioxin advisory is steadily diminishing. Since 1990, 13 states have lifted a total of 17 dioxin advisories from waterbodies downstream of U.S. pulp mills [5].

Moreover, as previously noted, EPA has analyzed the remaining dioxin advisories downstream of U.S. pulp mills against its BAT criteria. The study showed that following implementation of the proposed guidelines, all remaining dioxin advisories downstream of pulp mills would be lifted.

The following example illustrates the relationship between the increased use of chlorine dioxide, virtual elimination of dioxin, and eco-system recovery.

In July of 1989, responding to dioxin data released by Mead Corporation officials, the Michigan Department of Public Health issued a fish consumption advisory on an extent of the lower Escanaba River, downstream of the Mead Paper Co., Escanaba mill. At the time of the advisory, dioxin levels in northern pike and white suckers were reported to be between 2.9 and 24.4 ppt (parts per trillion). The Michigan Department of Public Health had established 10 ppt as the standard for issuing a consumption advisory.

The mill implemented pollution prevention strategies beginning with low precursor defoamers in May 1989; in April 1990, the mill increased chlorine dioxide substitution. These process modifications decreased dioxin in final mill effluent to non-detectable levels. Consequently, dioxin body burdens declined more than 90% in less than four years.

Responding to this improvement, the Michigan Department of Public Health lifted the Escanaba River advisory in 1993. All across the nation many waterbodies downstream of pulp and paper mills are experiencing similar improvements in the quality of aquatic eco-systems.

These environmental improvements are not limited to the U.S. The benefits resulting from the increased use of chlorine dioxide are occurring throughout Canada as well. New data show that, much like in the U.S., dioxin advisories downstream of pulp mills continue to be lifted. As a result of the dramatic decline in dioxin discharges, the Canadian Federal Fisheries Department has reopened many British Columbia coastal waters to non-commercial fishing. The data now show that dioxin levels in mill effluents have dropped by 93% from 1989-1994 [6].

VALIDITY

In the U.S., a number of studies continue to provide sound scientific data documenting the pollution prevention benefits of bleaching with chlorine dioxide. For example, reduced toxicity and reduced environmental impact are documented in a report titled, "A Review and Assessment of the Ecological Risks Associated With the Use of Chlorine Dioxide for the Bleaching of Pulp."

This peer-reviewed report concludes that "mills bleaching with chlorine dioxide (100% substitution) and employing secondary treatment and with dilution typical of N. American mills, present an insignificant risk to the environment from organochlorine compounds [7]."

The report further documents that the substitution of chlorine dioxide for chlorine results in:

Furthermore, in May of 1995, the Center for the Biology of Natural Systems released a report titled, "Quantitative Estimation of the Entry of Dioxins, Furans, Hexachlorobenzene into the Great Lakes from Airborne and Waterborne Sources." The findings of this report indicate that the pulp and paper industry is a negligible source of dioxin loadings to the Great Lakes [8]. This most recent analysis confirms the findings of earlier reports documenting chlorine dioxide's contribution to the pulp and paper industry's environmental progress.

As the above examples show, chlorine dioxide bleaching processes can easily be applied by the pulp and paper industry across the board. Over the last five years, the process has achieved remarkable success both in the U.S. and Canada and the rest of the world. Currently, responding to market demand and anticipated regulatory trends, approximately 40% of North American bleached chemical pulp is produced by mills that have converted to complete replacement with chlorine dioxide (ECF).

ECF bleaching, based on chlorine dioxide, has allowed the pulp and paper industry to achieve not only pollution prevention, but also virtual elimination of persistent, toxic, and bio-accumulative substances. As the industry looks toward the future, chlorine dioxide is laying the foundation for the success of "minimum-impact" mills.

  1. U.S. EPA. Regulatory Impact of Proposed Effluent Guidelines and NESHAP for the Pulp, Paper, and Paperboard Industry. November 1993.

  2. Pollution Prevention Act of 1990. 42 USC 18101. Laws of 101st Cong.-2nd Session.

  3. International Joint Commission. 1993-95 Priorities and Progress Under the Great Lakes Water Quality Agreement. August 1995.

  4. Berry, R.M., Fleming, B.I., Voss, R.H., Luthe, C.E., and Wrist, P.E. Toward Preventing the Formation of Dioxins During Chemical Pulp Bleaching. Pulp and Paper Canada, 90:8. 1989.

  5. Alliance for Environmental Technology. Eco-System Recovery: Liftings of Fish Consumption Advisories for Dioxin Downstream of U.S. Pulp Mills. August 1995.

  6. Government of Canada. Reduced Dioxin Levels Lead to Further Crab Fishery Reopenings. News Release. August 14, 1995.

  7. Solomon, K., Bergman, H., Huggett, R., Mackay, D., McKague, B. A Review and Assessment of the Ecological Risks Associated with the Use of Chlorine Dioxide for the Bleaching of Pulp. October 1993.

  8. Cohen, M., Commoner, B., Eisl, H., Bartlett, P., Dickar, A., Hill, C., Quigley, J., and Rosenthal, J. Quantitative Estimation of the Entry of Dioxins, Furans, Hexachlorobenzene into the Great Lakes from Airborne and Waterborne Sources. Centre for the Biology of Natural Systems. May 1995.