Environmental Challenges
Introduction
Within the pulping industry there are three main sources of pollution – wastewater, air pollution and solid waste. Wastewater typically originates from the pulping and bleaching stages of the process, involved in both washing black liquor from the pulp after digestion and bleaching the pulp to the desired extent. Washer effluent tends to be filled with hazardous chlorinated organic compounds, presenting a risk to the environment.
Solid waste tends to include sludge from the wastewater treatment and chemical recovery sections, ashes from boilers and furnaces, along with wood and bark residues from the wood handling section. Air emissions come from various parts of the pulping process, such as the recovery boiler, smelter, limestone kiln and incinerator. Sulphur dioxide, hydrogen sulphide and nitrogen oxides are some of the major environmental gases released (OECD, 2006).
Pollution from transport
Despite improvements of the pulp & paper industry in regards to environmental impact in terms of waste production the industry still emits GHGs in the form of fossil fuels, one source being the transport of materials across long distances. It involves transporting raw materials to a given mill, transporting pulp to a paper mill and transporting paper to either re-pulping factories or landfills/incinerators - on a global scale 10% of the total GHG emissions of the pulp & paper industry are due to transportation alone. Pollution generated from transport to China from Europe and America consists of 3.06 million and 3.77 million tonnes of carbon dioxide emissions respectively (OECD, 2010). Various industry leaders consider transportation to be an important environment issue for the foreseeable future (Ernest & Young, 2011).
Recycling
The use of recycled paper serves an integral part of the paper and pulp industry. Producing recycled pulp typically consumes far less energy than that of ‘virgin’ pulps (Kramer et al, 2009). In Europe the recycling rate reached a high of 71.7% in 2014 (CEPI statistics, 2015), and the US industry a high of 66.4 % in 2011 (Paper Recycles, n.d).
There are still issues with recovered pulp however, as the ability to manufacture it is limited to 6-7 times, as the fibre lengths degrade over time, and as such ‘virgin’ pulp must eventually be introduced to this process (OECE, 2010). In addition, recovering pulp in this manner creates more GHG emissions because obtaining recovered pulp requires the use of conventional fossil fuels.
Biomass/Energy
The industry has the opportunity to be a key enabler to produce biofuels, biodiesel and biochemical. Energy efficiency is a key issue for the industry, yet the industry already generates 50% of its energy from biomass and in the long run could develop into a clean energy supplier. An increasing demand for biofuels presents a challenge for the industry (OECD, 2008). This drive could increase pressure on the forestry-industry by increasing raw-materials costs for wood products, such as wood fibres. In addition, a growing demand for biofuels can lead to about 5 – 9 million hectares of additional deforestation, in comparison to a non-biofueled scenario (Uslu et al, 2010). Deforestation can lead to increasing carbon dioxide emissions as there is less biomass to absorb it (Theilmann, 2014).
Waste Production
Hazardous waste effluent remains an issue for the paper and pulp industry, yet there have been remarkable improvements in the amount of air, water and air waste effluent. The pulp industry contributes to a major use of water for various parts of the pulping process – close to an average of 200 m^3 treated effluent flow volume of water was discharged from the Canadian and American paper & pulp industries in the 1950s (NCAS, 2013). That figure has been reduced by
69% for the American industry with a similar result for the Canadian industry.
Solid waste is also generated, in many forms - mostly rejects from virgin pulp, green liquor and wastewater sludge (Bajpai, 2015). Since the 1960s there have been significant reductions in the amount of solid waste leaving mills (OECD, 2008).
In regards to air pollution, the paper and pulp industry releases greenhouse gas emissions (GHG) in the form of mostly Carbon dioxide and Nitrogen oxide, due to the combustion of on-site fuels along with the external generation of steam and electricity for mills (USEPA, 2010). By harvesting wood materials sustainably, the average CO2 emissions from pulping liquors are offset and therefore zero (OECD, 2010). Even under circumstances where sustainable harvesting of materials is not undertaken the average CO2 emissions are roughly a fourth of average coal emissions (OECD, 2010).
Overall there have been great improvements in the impact the production of paper and pulp products has upon the environment.
Diffusion of “Best available Technologies”
“Best Available technologies” (BAT) is a term which refers to techniques/technologies which are the most effective in achieving a high general level of protection of the environment as a whole, readily available to be implemented on an appropriate scale (EPA, n.d.). This concept as a whole is quite relevant when considering the environmental impact of the pulp & paper industry. As the Asia region’s per-capita income rises, its demand for pulp & paper products will continue to grow. As such in order to ensure that global CO2 emissions remain manageable, effort must be made to encourage the spread of low-carbon technologies into developing countries (IEA, 2009).
Written by: Christie O'Conner