The paper mills are making significant progress towards closing water circulations, which is the ultimate goal.
The UPM Changshu paper mill in China and the UPM Nordland paper mill in Germany are at the forefront of developing new technologies which aim to reduce water use and cut emissions through an intensive research and development programme.
In Germany, UPM Nordland will improve its wastewater treatment by investing in water purification technology. To be able to reuse treated wastewater in the paper mill process, the mill has to remove organic material and dissolved salts.
“After the treatment, approximately 20% of water can be reused in the first phase, which means that the corresponding amount of fresh water, as well as wastewater sent to the river Ems, can be reduced,” says Klaus Reimann, General Manager of Nordland Papier.
“The purified water also has a higher temperature than fresh water, so we can also reuse thermic energy.”
UPM Nordland Papier is the first fine paper mill to use this technology for recycling wastewater.
Taking good care of a scarce resource in China
In China, the UPM Changshu mill aims to decrease water consumption by 50% per paper tonne. In addition, their wastewater discharge is approaching zero emissions.
“We are currently piloting new solutions and technologies, together with partners, to recycle the water after it is released from the wastewater treatment plant. The treated wastewater will be further reused or combined in order to achieve zero discharge,” explains Corinne Le Ny-Heinonen, Manager, Environmental Support, UPM.
In the paper industry, the main methods of water treatment are a combination of mechanical and biological purification processes. After the first sedimentation stage, the water is cleaned biologically. Then it goes to final sedimentation and—if needed—filtration. The main challenge in the process is to remove dissolved organics, as measured by chemical oxygen demand (COD), from wastewater.
In China, UPM’s paper mill is located along the Yangtze River where COD emission restrictions are much tighter than anywhere else. “We respect and comply with the regulations and keep emissions under the limits. Now we are proactively taking one step further and investing in new technologies to reach our own challenging targets,” she says.
Challenging future targets
UPM has set challenging water-related responsibility targets for 2030, reflecting the Global Sustainable Development Goals (SDGs).
Regarding water, UPM focuses on reducing effluent organic load by 40% and wastewater volume by 30% compared to 2008.
“We also aim to use 100% recycled nutrients at our wastewater treatment plants by 2030. In order to reach our targets, we need to look for and develop new technologies,” says Le Ny-Heinonen.
“Each mill operates somewhat differently and the legislation varies from country to country, but we have to take into account the global impact as well.”
“In the pursuit of minimum water consumption and reaching certain emissions limits, we may come to a point where we have to use more energy or chemicals to reach the targets. These measures will have an environmental impact and increase costs as well. That is why we are looking for tailor-made solutions at each mill.”
“The closer we get to reaching our target, the more difficult the next step will be. However, it is worth continuing our efforts,” Le Ny-Heinonen concludes.