Great Reasons Why We Care:
TOWARD THE FUTURE
The prospects for continuing progress in minimizing the impact of the bleached pulp and paper industry on the Great Lakes eco-system are bright. In the short term, additional committed and planned actions by the industry will further improve the quality of effluent ultimately discharged to the Great Lakes.
The phenomena of subtle environmental responses to pulp mill effluent are being intensively investigated throughout the world. While the ecological significance of such responses has yet to be determined, the multi-country, multi-disciplinary, collaborative effort bodes well for development of understanding these issues and, if necessary, the creation and implementation of additional appropriate actions.
Voluntary commitments, proposed regulations, and market trends suggest conversion of the balance of bleached chemical pulp production in the Great Lakes Region to ECF by the year 2000.
In the longer term, technological research is shifting toward development of "closed-loop" systems for pulp and paper production. For bleached chemical pulp mills, development will be progressive, as many technical challenges must be overcome. ECF processes based on chlorine dioxide, may offer the best alternative for sustainability, product quality, and recyclability.
REGULATORY FORCESThe Canadian Environmental Protection Act (CEPA)
In Canada, regulations for persistent, bio-accumulative, toxic compounds affecting the pulp and paper industry are promulgated under an act of the national parliament: the Canadian Environmental Protection Act.
Based on an assessment of polychlorinated dibenzodioxins and polychlorinated dibenzofurans, regulations under CEPA were promulgated in 1992 to control the formation and discharge of polychlorinated dioxins and furans from Canadian bleached chemical pulp and paper mills .
Canada, unlike other nations and in contrast to many of its provinces, does not have a regulation limiting the discharge of chlorinated organic compounds as measured by the group parameter AOX (adsorbable organic halide). This decision is based in part on the findings of the CEPA assessment of "Effluents from Pulp Mills Using Bleaching" which concluded that AOX did not provide an estimate of environmental toxicity, persistence or bio-accumulation .
The province of Ontario has similar requirements for dioxin and furan as the CEPA regulations. In contrast, Quebec has a limit of 15 ppq TEQ based on all 2,3,7,8-substituted dioxin and furan congeners.
However, in contrast to the federal regulations, most provinces have existing and proposed future limitations on the discharge of chlorinated organic compounds as measured by the group parameter, AOX.
Regulations in the United States
On December 17, 1993, EPA proposed revised effluent limitations and pretreatment guidelines for all pulp, paper, and paperboard mills . EPA is expected to promulgate final regulations in 1996, with compliance within three years of enactment.
Regulations by EPA are developed using BAT guidelines. For bleached papergrade kraft, EPA is proposing limits at the bleach plant for TCDD, TCDF, twelve chlorophenolics (tri-, tetra-, and penta-substituted), and chloroform. The chlorophenolics listed by EPA as compounds of concern are readily eliminated by using ECF bleaching technology.
EPA has also proposed a number of guidelines for "non-conventional" pollutants. Specifically, AOX limits are proposed for final effluents from bleached kraft and sulfite mills. Guidelines for chemical oxygen demand (COD) are proposed for all kraft, sulfite, and semi-chemical mills except dissolving sulfite mills. In addition, guidelines for final effluent color (in platinum color units) are proposed for bleached papergrade kraft mills.
ECF pulp, bleached with chlorine dioxide, continues to be the fastest growing segment in the world bleached chemical pulp (BCP) market. In 1995, ECF manufacture will exceed 28.5 million tons, for a market share surpassing 40 percent. In all major pulp producing regions of the world, ECF demand is rising rapidly .
The Great Lakes Region is moving faster than the world at large. Based on current production and public announcements, in 1996, ECF will capture 60% of bleached chemical pulp production in the Great Lakes Region, as shown in Figure 4.1. Current regulations in Ontario and proposed guidelines in the US, along with market forces in North America and the rest of the world, strongly support the projection that by the end of the decade, all production in the region will be ECF.
Growth of ECF Production in the Great Lakes Region
RESEARCH AND DEVELOPMENTEnvironmental Responses to Pulp Mill Effluent
Having developed and implemented a strategy for virtual elimination of persistent, bio-accumulative, toxic compounds, research on the environmental responses to pulp mill effluent has shifted focus. Subtle responses such as the induction of liver enzymes in exposed fish are now the focus of attention in the scientific and technical communities. The ecological significance of such responses has yet to be determined.
Initially thought to be due to exposure to bleached pulp mill effluent, subsequent research has shown such subtle responses to be found at both bleached and unbleached pulp mills. Current research suggests the source may be natural wood extracts that are released into the environment during the processes which prepare the cellulose fibers prior to bleaching.
The research infrastructure of the pulp and paper industry throughout the world is engaged in the search for greater understanding and continuing improvement. Research is underway at industry organizations such as:
Governments throughout the world are also participating through such institutions as:
Academic experts at many leading universities are also collaborating and undertaking independent research exploring the same issues.
Taking inspiration from successful application of closed-cycle processes for mechanical and semi-chemical pulp mills, current research and development is focusing on technologies to "close the loop" to an even greater degree than is presently practiced at bleached chemical pulp mills. For example, in Canada, the federal government signed a Memorandum of Understanding with Paprican to focus research on closed-loop systems. Funding is estimated at $40 million over the next five years.
Pilot plant and demonstration processes for elimination of bleaching effluent are in operation and/or under construction at many facilities throughout the world. Processes are being developed for both chlorine dioxide based bleaching (ECF) and oxygen compound based bleaching (OCB).
Numerous process obstacles remain. For example, oxygen chemical based processes, ( i.e., ozone, hydrogen peroxide, peracids, etc.), require the residual lignin content of the unbleached pulp to be very low to achieve high brightness. The processes used to achieve low residual lignin content also lower the pulp yield, thereby increasing wood consumption 8-10% -- a finding with significant implications for sustainable production practices [32,33]. Furthermore, oxygen-based processes are less selective, deteriorating bleachability and product strength [33,34,35,36].
In the US, two demonstration projects may show the way for the future. At the Union Camp, Franklin, VA, mill, the bleach plant effluent from the ozone and alkali extraction stages is being substantially recovered to the unbleached part of the mill, thereby decreasing the volume of effluent to be treated . Champion International Corp.'s Canton, NC, mill is a demonstration site for the company's new technology, Bleach Filtrate Recovery (BFR®), designed to virtually eliminate bleaching effluent. The process will recover effluent from an ECF bleach plant. Effluent will be recycled to the unbleached part of the mill and excess sodium chloride removed .
The methods and mechanisms implemented by the pulp and paper industry, and discussed in this paper, have allowed the industry to achieve not only pollution prevention, but also virtual elimination, as witnessed by the decrease in fish dioxin body burdens and the accompanying lifting of advisories. As the industry looks toward the future, the success of process modifications, including ECF, has laid the foundation for the future success of "minimum impact" mills.
This report was prepared
by the Alliance for Environmental Technology