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Solutions To Damaging Mill Effluents

For more than a decade, researchers have been gathering evidence that suggests pulp and paper process effluents are adversely impacting the reproductive health of fish living downstream from mills. Yet, so far, there’s no clear understanding of the cause and effect and, more importantly, what practical steps mill operators can take to prevent this troubling environmental phenomenon.

All of that could soon change. Scientists and industrialists are now mobilizing their resources under a new research consortium that will tackle the scientific challenges in an unprecedented manner, while exploring sensible and cost-effective solutions for Canadian pulp and paper companies.

Spearheaded by the Pulp and Paper Research Institute of Canada (PAPRICAN) and Environment Canada’s National Water Research Institute (NWRI), the consortium will encompass an award-winning university-industry-government research team that has done more to advance knowledge and potential solutions surrounding the issue than any other group in the world.

“This will be the biggest research effort of its kind in Canada,” remarked Dr. Mark Hewitt, co-leader of the consortium and a research scientist at NWRI. He said the initial, two-year phase of the planned five-year research effort will involve total investment, both cash and in-kind, of roughly $5.7 million.

Dr. Hewitt, who is also an adjunct professor at the University of Guelph, ON, was part of a collaborative research team recently honoured by the Natural Sciences and Engineering Research Council (NSERC) with a Synergy Award for Innovation, a tribute that celebrates outstanding university-industry R&D partnerships. The coveted award acknowledged the team’s collaboration with Irving Pulp and Paper, Saint John, NB, in pinpointing the source of pulp mill effluents impacting the reproductive health of fish and in validating a potential technological remedy (see sidebar).

Dr. Hewitt shared NSERC’s Synergy Award with the leader of the university team, Dr. Deborah MacLatchy, professor of biology at the University of New Brunswick, and Dr. Monique Dub, who joined the research project as one of Dr. MacLatchy’s graduate students and who now holds the Canada Research Chair in aquatic ecosystem health diagnosis at the University of Saskatchewan. Under the new research consortium, that team will be joined by PAPRICAN’s effluent toxicity research group, led by Tibor Kovacs (co-leader of the consortium), and Dr. Glen Van Der Kraak from the University of Guelph.

“The NSERC Synergy Award,” Hewitt noted, “has provided us with the momentum to considerably expand our research in this area. The Synergy Award recognizes best-in-class collaboration between researchers and companies. And to move forward on this whole issue in a solutions-oriented way, we have to collaborate as we’ve never done before.”

“By collaborating with the universities and Environment Canada, along with as many as five mills and the Forest Products Association of Canada, we will be able to achieve a bigger impact by bringing more resources to bear on this issue,” explained Michael Paice, a senior scientist at PAPRICAN.

The issue of reproductive dysfunction in fish is traced to the release of chemicals known as endocrine disrupting substances (EDS). Endocrine systems release hormones that act as chemical messengers, interacting with receptors in cells to prompt normal biological functions such as growth, embryonic development, and reproduction.

In pulp mill effluents, a broad class of phytoestrogens, derived from plant material, may account for some endocrine disrupting effects. But pulp mills are by no means the only source of EDSs. Endocrine disruption has also been linked to pesticides from agricultural run-off and municipal sewage containing trace amounts of synthetic steroids have been found in birth control pills.

PAPRICAN has been investigating the EDS issue since 1992, and it has recently found that masculinization and an interruption of egg production occurred when fathead minnows were exposed to different concentrations of certain pulp mill effluents.

Those findings have since been confirmed by university and government researchers, and by statistical analysis of data collected from more than 120 mill operators who conduct regular assessments of downstream organisms under Environment Canada’s Environmental Effects Monitoring (EEM) program. According to Dr. Hewitt, results from the first three EEM cycles over the last decade show abnormally large growth of fish and aquatic insects as well as reduced gonad sizes in fish living downstream from pulp and paper operations.

Hewitt said the EEM program will be key to marshalling resources in support of the new collaborative R&D effort. “There’s enough flexibility within EEM to allow mills to satisfy the regulatory requirements of the program by contributing to this new research consortium.”

The consortium’s first order of business is to correlate the EEM field data with laboratory-based EDS assays in a bid to develop a simple set of bioassay tools. These will enable scientists to accurately simulate in a lab the field conditions that trigger endocrine disruption responses in fish.

“This is a very complex scientific challenge, in terms of both cause and effect,” Dr. Paice noted. “It appears that there is more than one chemical responsible for endocrine disruption. At the same time, we know that endocrine disruption is manifested through a variety of different pathways with EDSs targeting receptors in the fish’s brain, liver, and gonads. Our primary objective is to find a solution to the EDS problem, even if we are unable to precisely identify the causative agents.”

Paice said part of the solution could already exist in secondary effluent treatment operations, established by more than 90% of Canadian mills since the mid-1990s. The secondary treatment systems, which employ microorganisms to remediate mill effluents, were the main component of an industry-wide investment of roughly $6 billion to meet new environmental regulations introduced in 1995.

The regulations were designed to limit the release of bio-chemical oxygen demand (BOD) substances, treat total suspended solids, and eliminate acute toxicity in rainbow trout.

Paice said the EDS problem might be solved by optimizing secondary treatment facilities, including adjustments to nutrient balances, or by altering certain in-mill processes. “Secondary treatment already does a good job of taking out a lot of chemicals that potentially could cause an endocrine disrupting effect. We don’t want our mills to invest in something new if the solution is already, at least partly, at hand.”

Hewitt agreed. “In fairness to the industry, secondary treatment systems were never intended to eliminate this kind of problem. But if those systems can be made more responsive to the EDS issue, then we can maximize an already considerable investment in pollution control facilities.”

Irving sheds important new light on EDS sources in pulp mills

The experience of Irving Pulp and Paper (IPP) with innovative pollution prevention technology has supplied Canadian scientists with some of the greatest insights to date concerning the adverse impact of effluents on fish living downstream from pulp mills. Working with university researchers, supported by R&D partnership funding from the Natural Sciences and Engineering Research Council, IPP demonstrated that in-mill effluent treatment technologies may be the most reliable way of eliminating endocrine disrupting substances (EDSs) that damage the reproductive health of fish.

“We really stumbled upon this,” IPP environmental coordinator David Muir explained. “When we decided to implement our unique effluent treatment technologies, the goal was to satisfy the new BOD (biochemical oxygen demand) regulations governing pulp mills. Unwittingly, we were also removing compounds, still not fully understood today, that are responsible for disrupting normal reproduction in fish.”

“There was a bit of serendipity involved here for sure,” remarked Deborah MacLatchy, professor of biology at the University of New Brunswick, Saint John. “We wanted to find out what was causing the problem, but we had no idea we would also validate a potential solution.”

IPP’s solution was driven by a reality that prevented the company from establishing a secondary treatment lagoon, as the majority of Canadian pulp mills did, to meet the BOD regulations. Because IPP’s kraft mill is in the heart of Saint John, there was insufficient property to establish a secondary treatment pond.

As a result, IPP focussed on an in-mill solution, of which a key component is reverse osmosis (RO) technology pioneered by Zenon Environmental, Burlington, ON. The RO solution, the same used by municipalities and homeowners to purify drinking water, was added in a world-first, application for filtering and recycling both water and chemicals used in the pulp and paper process.

RO technology involves membranes that separate molecules. At IPP, more than 200 membranes on five-feet-by-ten-inch spools remove up to 15 gallons of concentrated filtrate each minute from the evaporator condensates waste stream.

“By turning the RO system on and off,” Dr. MacLatchy said, “we were able to pinpoint the condensate waste stream as the source of endocrine disrupters at Irving’s mill.” She added that the same stream, tested more recently at an Ontario mill with secondary treatment facilities, was identified as a source of EDS contaminants.

An important aspect of these findings, she said, is that the researchers have established an investigation of cause (IOC) methodology that has been accepted by Environment Canada under the Environmental Effects Monitoring (EEM) program. As a consequence, she said a lot of previous critics have been converted into supporters of the scientific methodology chosen by the university researchers.

Mr. Muir said IPP has seized this development to become the first pulp and paper company in Canada to get the green light for IOC under EEM. “We’ve had resounding support from Environment Canada to take this important next step in discovering why this EDS phenomenon is occurring.”