Forest ranger

Forest ranger

To preserve the health of our forests and keep deadly chemicals out of the human food chain, a UNB researcher has developed new, environmentally friendly technology
June 1, 2004

As a boy, Yonghao Ni was fascinated by the huge pulp and paper mill near his home in Jiaxing, China. Today, half a lifetime and half a world away, Ni's fascination with pulp and paper has turned into a full-time passion—and earned him a reputation as one of the world's foremost forestry researchers.

Ni is a professor of chemistry and chemical engineering at the University of New Brunswick (UNB) in Fredericton. His work is helping to cement Canada's reputation as a world leader in forestry science. Ni and his team at UNB are working on ways to reduce the environmental impact of forest products like pulp and paper. It's all part of a multi-disciplinary approach that tackles forest industry challenges by combining chemistry and forestry management.

"Growing up close to a mill in China got me interested in the pulp and paper industry. That's what motivated me to pursue my university degree in this field," says Ni looking back on the path he's taken since childhood. He says China and Canada are similar because both have a thriving forestry sector that produces vast wealth but also has a big impact on the environment.

"Fredericton is similar in some ways to Jiaxing where I grew up. It's a small town with a good network of mills nearby—very much like New Brunswick" says Ni, who is also Director of the Dr. Jack McKenzie Limerick Pulp and Paper Research and Education Centre, and holds a Canada Research Chair in Pulp and Paper Science and Engineering. Today, he works closely with mills in New Brunswick to find ways to make pulp and paper mills more environmentally friendly.

One of the biggest challenges that the pulp and paper industry faces is figuring out how to eliminate chlorine from the paper making process. Canadians are familiar with chlorine as an essential chemical that allows us to take clean drinking water almost for granted. But pulp and paper mills that use chlorine to bleach wood pulp produce harmful chemical by-products that get into the air, water, soil, and food chain.

To help deal with the problem, Ni has developed the PM (modified peroxide) process. It's an improved hydrogen peroxide bleaching process for brightening mechanical or ultra-high yield wood pulps that are used to make paper. Not only does Ni's technology replace chlorine, it also produces higher quality and brighter paper products. As an added environmental bonus, the technology requires less water, which means less wastewater is pumped into rivers by pulp and paper mills.

Low implementation costs and big savings—compared with conventional methods—also mean there's commercial potential for world-wide application of Ni's process. Industry partners are already on board. Ni is working closely with Nexfor and its Fraser Papers mill in Edmunston, New Brunswick. His team is also working with the Irving Pulp and Paper plants in Saint John, and collaborating with other industry partners to manage forests to ensure the long-term sustainability of high-quality wood fibre. Ni says the key to success is teamwork.

"Forest product manufacturing is an integrated process where foresters, wood scientists, and paper engineers should all be working together." It's this collaborative approach, along with an enlightened attitude, that Ni hopes will soon be prevalent at paper mills everywhere—whether in Canada or half way around the world.


Keeping Canada on the cutting edge could also mean big economic benefits. Forestry is a key industry in Canada employing more than 350,000 people and is worth about $74 billion. The second-largest producer of wood pulp, Canada is the world’s largest pulp exporter, supplying one quarter of the international market.

The work of Yonghao Ni and his team at the University of New Brunswick (UNB) is contributing to a healthy environment and a strong economy in Canada. The team’s research is leading to the development of more environmentally friendly processes for the bleaching of chemical pulps. The new processes will replace the use of chlorine—a chemical that disrupts the environment and affects human health. The danger to humans occurs when pulp and paper mills that use chlorine to bleach pulp produce chemicals called organochlorines, which end up in the human food chain. Among the most deadly organochlorines are dioxins—potent toxic chemical by-products of chlorine bleaching.

To date, over 1,000 organochlorines have been found in chlorine-bleached pulp mill wastewater. Once released, these chemicals persist in the environment, spread through the food chain, and accumulate in fatty tissues. They are known to disrupt, mimic, and block hormone systems—which are responsible for regulating reproduction, learning, behaviour, and disease fighting in humans and wildlife.

The global forestry industry is under pressure from governments and environmental groups to meet higher standards for using chlorine and other potentially harmful chemicals that can have a negative environmental impact. Ni and his team are working with industry to produce technologies that will keep Canada on the cutting edge of the forest products industry with cleaner, more efficient processing methods.


Irving Pulp and Paper does more than collaborate with Yonghao Ni and his team at the University of New Brunswick. Irving works with the New Brunswick Department of Education's Partnership for Education. The partnership offers interactive curriculum materials for students to learn about forestry and careers in the industry.

Other funding partners include:

• Dow Chemicals

• Nexfor

• Tembec

• Neill and Gunter

• Martin Marietta

• St. Anne Nackawic Pulp Company

Learn More

Take a virtual tour of the Irving sawmill in Scierie Grande-Rivière.

Visit the website for the Reach for Unbleached Foundation.

Learn more about Canada’s Forests from Natural Resources Canada.

Find out about the Dr. Jack McKenzie Limerick Pulp and Paper Research and Education Centre.