Paper industry is getting greener?
Arbor Day, which falls on April 28 this year, was established in the United States in 1872 as a day to plant and care for trees. To mark the event, Gary M. Scott, chair of the Paper and Bioprocess Engineering Department at SUNY’s College of Environmental Science and Forestry, answers five questions about the pulp and paper industry – a major consumer of trees.
1. Does paper manufacturing contribute to deforestation?
Pulp and paper companies often are accused of cutting down trees to make paper. However, 39 percent of the fiber used for papermaking comes from recycled paper. Most of the remaining wood is obtained either through forest thinning (removing slow-growing or defective trees) or from lumber milling residues – materials that otherwise would go unused. Only 36 percent of timber harvested in the United States is used directly to make paper and paperboard.
Each year the amount of wood harvested from U.S. forests is much less than annual forest growth. Land covered by forests in the United States increased by 4.5 percent between 1997 and 2012, even as suburban development expanded.
The industry works very hard to protect its raw material sources. Mills have the option to use wood certified as coming from sustainable forests. Timber companies and land owners manage and harvest their forests to maintain forest productivity and health, protect water resources and biodiversity and preserve opportunities for hiking, fishing, hunting and camping.
Production of timber, pulp, and paper is often described as a major driver of global deforestation. This is true to some extent, but the industry is changing its practices to be more environmentally responsible. It’s also important to note that 73 percent of deforestation in tropical and subtropical areas is for agriculture, mainly producing palm oil, soybeans and beef.
Consumers can encourage sustainable use of wood by purchasing only products that display certifications from groups such as the Forest Stewardship Council and the Sustainable Forestry Initiative.
2. Historically, pulp and paper mills have been major pollution sources. Is this changing?
Yes. Over the past 50 years, this industry has become much more environmentally aware. For mills that use wood as their raw material, almost every component of the wood is made into something useful. Bark removed from logs before pulping is usually burned for energy, which provides a biomass-based, renewable energy source.
In the most common pulping process, chemicals are regenerated through a complex sequence of processes, and wood byproducts are burned for energy. Residual ash is often used in construction materials such as concrete, or for road construction.
Pulping and paper-making yields many other co-products in addition to energy. They include turpentine, rosins used to make adhesives and rubbers, sulfonated lignin (a material used in making concrete, drilling mud and drywall) and even imitation vanilla flavoring. Residual fibers from paper recycling can be used for other purposes, including mulch, animal bedding and soil amendments.
The industry also has greatly reduced the quantity of materials that it discharges to the environment over the past 40 years. In 2015, it accounted for just 5 percent of the 27.24 billion pounds of production-related waste reported by U.S. manufacturers.
Pulping and paper-making are very energy-intensive, but much of the power comes from renewable sources. In 2012 two-thirds of the energy used by U.S. paper mills, including both electricity and heat, came from renewable sources, and the pulp and paper industry accounted for 62 percent of biomass-sourced energy used in all manufacturing facilities nationwide, across all industries. Because it uses so much biomass energy, the industry has reduced its carbon footprint per ton of product by over 55 percent since 1972. Some mills actually produce more electrical energy than they need and sell “green” energy back to the grid.
3. How much paper is recycled?
Paper is one of the most-recycled materials in the world. In 2015, about 67 percent of all paper was recovered for reuse. For comparison, only 27 percent of glass, 35 percent of metals, and 8 percent of plastics were recovered. According to the Environmental Protection Agency, more paper is recovered from the municipal solid waste stream than glass, plastic, steel and aluminum combined by weight.
Every ton of paper recovered reduces the amount of materials sent to landfills by 3.3 cubic yards, extending the useful life of many landfills. The paper industry has set a recycling goal of 70 percent by 2020.
4. Is the digital revolution making paper obsolete?
Not at all. Even with the growth of digital media, we still use paper for newspapers, books, letters and maps. And we all use other paper products daily, including personal care items (bathroom and facial tissue, bandages and disposable hospital gowns), packaging (envelopes, boxes, folders), building materials (insulation, gypsum board), toys and games (playing cards, games) and paper money.
To make those products, the U.S. pulp and paper industry produces about 78 million tons of paper per year with a value of US$187 billion. It directly employs 373,400 people, with an annual payroll of over $30 billion and an average annual salary of $81,300.
The industry hires hundreds of engineers each year. Many have studied at our college or one of the other U.S. schools that offer B.S. degrees in paper engineering: North Carolina State University, the University of Wisconsin – Stevens Point and Western Michigan University.
5. What kind of innovation is happening in the paper industry?
Our raw materials, manufacturing processes and products all are evolving. New technologies are spurring new uses for paper and development of more co-products, such as transportation fuel and biodegradable plastics. Nanocellulose, a very lightweight material made from wood fiber, is stronger than Kevlar and has many potential uses. That’s also true for another emerging technology: cheap, flexible electronic circuits that can be printed on paper.
Some of these products could be made soon in forest biorefineries – facilities that make a wide range of products from wood, much as oil refineries make multiple products from crude oil. The U.S. Department of Energy has funded 13 pilot-scale and larger biorefineries across the nation that are producing ethanol and renewable hydrocarbons from wood. I expect that in the future, paper mills will produce a wide range of products such as transportation fuels, adhesives, chemicals and other materials – serving society’s needs without a drop of oil.
Dr. Scott teaches Principles of Mass and Energy Balances, and Computing Methods for Engineers and Physical Scientists. His research involves the use of biotechnological processing in the pulp and paper industry. He has investigated the use of a fungal pretreatment for the production of mechanical pulp and has worked on the scale-up of the process to the semi-commercial scale. Currently, he is involved in the extraction of hemicellulose from wood for the co-production of chemicals together with paper. Dr. Scott is also involved in process modeling of pulp, paper, and bioprocess systems.
Source: The Conversation US, Inc.