The Case for ECF
by Douglas C. Pryke
Recycled Paper News*
Most people in the printing, publishing and graphic arts industries have developed their own preferences for paper quality and characteristics. What many may be unaware of is the processes involved in making paper bright and the environmental quality of those processes.
Purchasers need the necessary information to make an informed decision in the paper purchasing practices.
Today the industry - the producers, distributors and even the end users - find themselves in the midst of a debate: The chlorine debate.
There are those who have called for a ban of chlorine and its use in bleaching pulp, the raw material for papermaking.
What many don't know is that there is an alternative to chlorine - ECF.
ECF (Elemental Chlorine-Free) processes, based on chlorine dioxide, provide an environmentally-superior product, without sacrificing product quality.
All agree that there is a clear and urgent need to eliminate persistent, bioaccumulative, toxic substances from mill waste water resulting from the pulp bleaching processes. The conversion to chlorine dioxide in the first stage of chemical pulp bleaching has addressed, and virtually eliminated, these priority pollutants, including dioxin, from the bleaching process.
New science, a proven environmental track record, and a strong market demand demonstrate that ECF is without rival in terms of pollution prevention, resource conservation and product quality.
To fully understand both the environmental benefits and the improvements in product quality resulting from the use of chlorine dioxide, we must first understand the fundamental chemistry behind the process.
In chemistry, a single atom can make a world of difference.
The chlorine dioxide molecule consists of one chlorine atom and two oxygen atoms. In contrast, elemental chlorine consists of two chlorine atoms. As such, chlorine dioxide's chemical properties are very different from that of elemental chlorine and they yield very different end results.
These differences make chlorine dioxide not only a superior bleaching agent, but one with distinct environmental benefits. During the pulp bleaching process, both chlorine and chlorine dioxide can form chlorinated organics. However, whereas chlorine tends to combine with lignin - the substance that holds the wood fibers together - chlorine dioxide typically breaks apart the lignin.
Any remaining chlorinated organics formed by chlorine dioxide bleaching are water soluble and non bio-accumulative.
Instead, they are very similar to chemical substances occurring naturally in the environment.
Complementing its strength is its selectivity.
Chlorine dioxide attacks lignin and other substances such as resins, while preserving the wood's cellulose fibers - those that provide the strength in the final paper products.
These properties have made chlorine dioxide the fastest growing and most effective bleaching agent in the manufacture of pulp, the raw material used in the production of paper and paper products.
ECF pulp quality is excellent.
Studies show that ECF bleached products can achieve high brightness (89-90 percent ISO) and high strength (burst, tear, tensile, viscosity).
Other bleaching processes are less selective and consequently have not been able to retain high strength at full brightness.
A number of recent studies have shown that other processes, including Totally Chlorine-Free (TCF), may actually reduce the fiber strength and the tear strength at full brightness by approximately 10 percent.
A low fiber strength may limit recyclability.
TCF processes also may have lower yield, requiring more wood to make the same amount of paper, thereby increasing the strain on our-precious forest resources.
In addition to product quality, a great deal of attention has been focused on the environmental benefits of chlorine dioxide bleaching. Throughout North America dioxin discharges from pulp and paper mills to waterways have decreased by more than 96 percent since 1988.
One needs to look no further than the state of our nation's waterbodies to find documentation of ECF's superior environmental performance. Since the industry began its conversion toward ECF bleaching we have witnessed a rapid recovery of the environmental health of aquatic ecosystems across the country. In the U.S., fish consumption advisories have been - and continue to be - lifted as dioxin levels in fish downstream of pulp mills continues to decline.
These indicators of progress and broader eco-system integrity mark the success of the pulp and paper industry's use of chlorine dioxide.
An analysis of the June 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 fish consumption advisories for dioxin from waterbodies downstream of U.S. pulp mills.
Moreover, EPA has analyzed the remaining dioxin advisories downstream of U.S. pulp mills against its Best Available Technology (BAT) criteria, currently based on ECF processes.
The study showed that following implementation of the proposed guidelines, all remaining dioxin advisors downstream of pulp mills would be lifted.
As testament to this success, in July 1996 EPA issued its "Notice of Availability" for the agency's proposed Cluster Rule for the pulp and paper industry. In the notice EPA proposed two options for Best Available Technology, both based on ECF (100 percent substitution of chlorine dioxide for chlorine).
The Canadian industry has seen much the same in terms of ecosystem recovery.
In October 1996, Environment Canada and Health Canada released a report documenting the end of inadvertent dioxin emissions from pulp mills, coupled with the reopening of 46 percent of British Columbia's coastal fisheries previously closed by dioxin contamination.
Combined with a strong environmental performance, product quality has made ECF pulp the fastest-growing segment in the world bleached chemical pulp (BCP) market.
In 1997 ECF manufacture is expected to reach 38 million metric tonnes, or 50 percent of the world market (see chart). In all major pulp producing regions of the world, ECF production continues to rise.
In Scandinavia, ECF demand remains strong, accounting for 75 percent of bleached chemical pulp production - triple that of TCF.
The demand for TCF has stalled and some producers are responding by shifting a greater percentage of their production to ECF. Signaling a turning point in Scandinavian pulp production, one of the largest TCF producers will increase production of ECF in 1997.
In North America, ECF production will increase by 16 percent in 1997 to represent 55 percent of bleached chemical pulp production. In contrast no growth in TCF production was seen in 1996, nor is any projected for 1997 (see chart).
Separately, in 1997, Canadian BCP production of ECF will grow by 7 percent, to 8.7 million tonnes, holding more than 70 percent of the market.
In the United States, ECF continues to grow rapidly, with an additional 2.4 million tonnes entering the market in 1997, growing by 23 percent, to nearly 13 million tons, or 47 percent of U.S. bleached chemical pulp production, an increase of more than 2000 percent since 1990.
Numerous studies over the last couple of years have examined the relative environmental quality of waste waters from mills operating with ECF and TCF bleaching processes.
In the summer of 1996, the London-based International Institute of Environment and Development released a report entitled, "Towards a Sustainable Paper Cycle."
The report assessed the role of the international pulp and paper industry in everything from forestry to pulp and paper production to recycling and disposal.
In examining the questions surrounding bleaching practices and the current environmental debate, the Institute concluded that "there is no appreciable environmental difference between TCF and ECF processes."
As many international scientific, regulatory and public interest groups worldwide reach consensus that this environmental debate is indeed over, research is now turning toward development of a minimum-impact mill.
The vision of the minimum-impact mill is viewed as the industry's next step. Minimum-impact mills will reduce water use, minimize raw materials, maximize energy production and produce high-quality products while striving for aesthetic appeal.
As research progresses, preliminary conclusions and operating experience show that ECF is compatible with, and may become the cornerstone of, the minimum-impact mill of the future.
With results like these, superior environmental performance and product quality, no wonder ECF is becoming the dominant product in every world market.
For more information, call AET at (800)-999-PULP.
*Used with permission from Recycled Paper News.