Turning used cardboard lunch boxes into fuel? Paper mills hold the secret weapon
Dec 19, 2021

Every individual person produces a mountain of paper containers on a daily basis: the paper container for breakfast takeaway, the paper cup for coffee, the paper bowl for a noodle soup for lunch, and dinner in a bento box.

Taiwan’s volume of paper container usage keeps climbing year after year. According to calculations by the Taiwan Environmental Protection Administration (EPA), more than 16 tons of paper containers were recycled last year, nearly twice the volume of 2016. However, the question remains: What happens to them after recycling?

Perhaps Cheng Loong, Taiwan’s largest paper manufacturer, is not a familiar name to most people, yet everyone in Taiwan has certainly used their toilet paper and kitchen towels. In fact, four out of every 10 cardboard boxes, shoeboxes, and cake boxes used in online shopping are made by Cheng Loong.

As early as next year, one out of every two paper cups and bowls used for food deliveries will be recycled and manufactured by Cheng Loong into boxes or packaging

In order to achieve this, Cheng Loong has made numerous preparations, investing billions of NT dollars. And in addition to giving paper containers a place to go beyond a single use, while reducing CO2 emissions, the company can save over NT$100 million per month in costs.

Secret Weapon #1: Plastic slag converted into fuel pellets
Mountains of cardboard boxes and paper containers are not rubbish, but rather precious raw materials. Paper is carried on a conveyor belt and tossed into a machine resembling a large blender. Water is added, and the mixture is reduced to paper pulp. Plastic slag is then sifted from the pulp, shredded, and compressed to make oblong fuel pellets.

This solves the key issue of the proper recycling of paper containers.

Paper containers are not just made of paper. Bowls and bento boxes are all lined with a type of plastic known as coated paper. These rejects are sifted out during the recycling process. “See, inside are plastic pieces, tape, and staples,” remarks Wu Wen-chen, director of the Cheng Loong facility in Zhubei, as he fishes out the slag material.

Around one ton out of every 10 tons of recycled paper is non-recyclable waste. In the past, one had to pay a hauling service to deal with it. But the problem only grew worse. Wu relates that Cheng Loong began processing used paper containers in 2018, and the explosion in food deliveries in recent years has seen a commensurate surge in paper containers, pushing the costs of waste treatment higher.

However, Japan’s paper industry has been turning shredded plastic into substitute fuel for years. Cheng Loong has worked with the Industrial Technology Research Institute (ITRI) in recent years to turn slag into fuel, both alleviating the issue of waste materials while reducing use of coal for fuel.

Secret Weapon #2: New cogeneration plant uses recycled fuel, reducing 30,000 tons of coal a year
Where are fuel pellets used? The second secret weapon can be found in the Zhubei facility: the cogeneration fcility under construction, which costs the company an investment of NT$1.7 billion.

Wu explains that steam is used in the paper production process to dry out the pulp. In the past, the boilers were all coal-powered, but this new boiler - slated for operation early next year - will use fuel pellets made from slag for half of its fuel. “At the highest ratio it can go to 100 percent,” Wu claims.

Looking forward, the waste materials produced from the recycling process at the Zhubei facility can all be processed by the boiler. Cheng Loong currently consumes 3,000 tons of coal every month, which can be reduced by 30,000 tons annually in the future.

Another headache is wastewater.

Secret Weapon #3: Using biogas generated from wastewater treatment to produce renewable energy
The third secret weapon is biogas power generation.

On the other end of the Cheng Loong Dayuan facility stand two anaerobic organism treatment systems. Chang Tzu-chieh, section chief at the Dayuan facility, relates that paper production generates wastewater and sludge, and systematic treatment of wastewater produces methane gas. Once that is desulphurized, it can be used to generate electricity.

This knowledge has actually been hard-won through experience. Back in 2015 at Cheng Loong’s Houli facility near Taichung, the foul stench of wastewater caused public protests. Residents were seen asking for “completely odor-free” wastewater.

And now, Cheng Loong has turned that setback into an opportunity for transformation, even developing new commercial opportunities.

Methane power generation is a form of renewable energy, thus it can be thought of as “turning wastewater into green gold.”

By the end of 2021, the plan is to combine the two methane electricity generators at the Dayuan plant to the electrical grid, potentially supplying enough electricity for 4,000 small families to use; each year reduction of carbon absorption equivalent to 20 Da’an Forest Parks can be achieved. Wu says that, with the help of feed-in-tariff, the company expects that the biogas facilities will pay for themselves in around two years.

Protecting the environment can also be profitable. Chen Ching-yi, director of Cheng Loong’s Department of Sustainable Development, relates that in-house treatment of recycled paper slag and wastewater sludge can save at least NT$100 million per month in processing costs.

Starting next year, Cheng Loong’s role in paper meal carton recycling is set to expand. Currently, the Zhubei facility processes around 1,400 tons per month, which is expected to quadruple in three years. The big show was at the Dayuan facility, where the addition of new production lines can treat 10,000 tons of paper cartons every month.

In the second half of next year, Cheng Loong will be able to process recycled paper containers, or approximately the same volume as Lientai, Taiwan’s earliest paper container recycling firm.

Lientai company president Lien Ta-chun remarks that Cheng Loong is expanding recycling production lines for paper containers to improve competitiveness.

In response, Lientai plans to search for more waste paper with the potential for use as resources, as well as develop ways to improve the paper container recycling material flow system, so as to expand resource sourcing.

However, simply increasing processing capacity is not enough; paper container recycling continues to face assorted challenges.

The dilemma: Taiwan’s recycling system does not benefit paper recycling
First is the difficulties of the recycling system, which results in a lot of paper containers ending up in incinerators.

Signs at many apartment complexes in the Greater Taipei region tell residents: “Discard paper meal cartons in the garbage.”

Why is this the case? Lien Ta-chun relates that this is related to recycling foundations and cost calculation by volume. Apart from the east coast and outlying islands, subsidies for paper container recyling are uniform everywhere in Taiwan, so that mountains of paper containers have to stack up everywhere before a ton of weight is reached, making it less profitable than glass bottles and aluminum cans. Especially in urban areas, the slim profits mean that few people are willing to engage in recycling.

Another issue is the difficulty with storage. Paper containers easily attract cockroaches and ants. For Greater Taipei region apartment and office building rubbish removal companies, the cost of cleaning and collection is high, plus the EPA gives recycling firms a standardized rate nationwide. The result is that the majority of Liantai’s paper container recycling clients are located in the central and southern parts of Taiwan.

Furthermore, although recycled paper meal cartons are currently not made into recycled toilet paper in Taiwan, in Japan milk cartons are being recycled into toilet paper.

In Europe and Japan it is common to see little dark spots on toilet paper, which is a telltale sign of recycled toilet paper. Wu Wen-chen says that the proportion of recycled toilet paper in Europe and Southeast Asia is around 50 percent, 65 percent in Japan, but just five percent in Taiwan. This is because Taiwanese consumers prefer paper made with virgin pulp, or “pure white” toilet paper, deeming it clean that way.

Cheng Loong company president Chang Ching-Biao laments that “Taiwan has no logging industry, and all raw paper pulp is imported. So turning it into toilet paper is a shame.” Chang believes that the public will need to reverse its set impressions if it is to raise acceptance, and resources can be appropriately utilized.

When separation is done well, it allows for resources to go where they are needed. A good environment needs everyone’s best efforts.

By Kwangyin Liu
Photo credit / Ming-Tang Huang