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| Irving Pulp & Paper's reverse osmosis system. |
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| Irving Pulp & Paper's reverse osmosis system. |
To meet government regulations, most pulp and paper mills built conventional secondary treatment lagoons. Treating pollution after it has exited the mill pipe in a secondary treatment lagoon has been the standard technology, enabling mills to meet regulations with limited costs.
Faced with local opposition to a lagoon, Irving Pulp & Paper underwent a complete Environmental Impact Assessment. After researching other options, the mill, which is located in Saint John, New Brunswick, decided to go in an unprecedented direction. Irving Pulp & Paper launched a pollution prevention strategy to recover, reduce and reuse pulp-making materials in the mill. It is believed that no other kraft pulp mill in the world has ever attempted this approach.
The New Brunswick-based mill planned their strategy around the best known technologies of the day. At the time of design there were not enough known technologies to take them all the way to environmental compliance. They believed that with the rate of technological advancement and the ongoing research, new technology would evolve by the time the known technologies were in place.
Irving Pulp & Paper achieved environmental compliance through innovation and determination. Three key pieces of technology, one for which the company has been granted the patent, have enabled the mill to meet federal government regulations. These technologies, used in novel applications, set Irving apart from all other pulp mills in the world, says a company report. The new technologies include: two-stage oxygen delignification, reverse osmosis, and a moving bed bioreactor.
Reverse osmosis, the same system used by municipalities and homeowners to purify drinking water, was added in a world-first application to filter water used in the pulp making process. "Reverse osmosis had intriguing characteristics," explains George Rogers, Site Manager of Irving Pulp & Paper. "But it had never been used at a pulp mill before."
One of these characteristics is the opportunity to selectively remove compounds through the use of specialized internal membranes. These membranes, which differ in size and shape, are customized to remove targeted compounds. Other molecules, like water, are allowed to pass through the system. In a home filtering unit, the system may consist of one or two membranes. At Irving Pulp & Paper, 210 membranes on 5' x 10" spools remove 10 - 15 gallons of concentrated filtrate each minute. The concentrate is incinerated and the filtered water is recycled in the mill to be reused in the process.
Reverse osmosis has played a significant role in lowering pollution levels in the mill, and in an important discovery, researchers found that the system removed compounds responsible for endocrine disruption in fish. Endocrine disruption is a global environmental issue affecting normal hormonal processes in humans and wildlife. Potential effects include mild to severe reproductive problems. The reverse osmosis system eliminates Irving Pulp & Paper's potential for endocrine disruption in fish at Reversing Falls.
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| Close-up of one of the system's membranes. |
Deborah MacLatchy, a professor at the University of New Brunswick, Saint John, who has been studying the issue of endocrine disruption near the Irving Pulp & Paper mill for the past three years, noticed significant improvements once reverse osmosis was installed. "Reverse osmosis removed compounds responsible for endocrine disruption in fish," Dr. MacLatchy states. "This is significant. Irving Pulp & Paper is further ahead on the endocrine disrupter issue than probably every other mill in Canada."
Researchers at Environment Canada are working with Dr. MacLatchy to study the compounds responsible for endocrine disruption in fish near pulp and paper mills. Many research institutions are interested in Dr. MacLatchy's work and she has been invited to speak at numerous national and international conferences.
The significance of this advancing technology in the pulp and paper industry is clear. Mills now have a viable alternative solution to conventional secondary treatment facilities. Wally Vrooman, past president of the Pulp and Paper Association of Canada, also believes this helps put the mill and the country on the map. "It's a new option everyone has they didn't have five years ago. And if it's cost competitive or better, it's one the industry should consider. This is a technology the company can export. It's great for Canada to have technology that they can give back to the industry."
Richard McLean, Environmental Coordinator for the mill, gives credit to the owners for making a choice that many other mills would not have been able to consider. "A secondary treatment facility costs $58 million. We spent $300 million. I doubt the board of directors of a publicly traded company, concerned about share value, would ever have allowed this to be happen."
Willa Mavis, a vocal opponent back in 1992 to the proposed lagoon at Sheldon Point, is pleased with Irving Pulp & Paper's efforts. "In addressing community concerns," she says, " a real scientific advancement has been achieved for the industry."
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