Turning Trash into Treasure

Lotos and Guantian’s “Black Gold”

2020 / February

Lynn Su /photos courtesy of Jimmy Lin /tr. by Scott Williams

In this age of excessive materialism, we tend to prefer new to old and quickly dispose of anything used. We’ve traveled this path for so long that we’ve stuffed Nature’s gullet with trash. With the natural world now rebelling at last, humanity is slowly awakening to the problem. We have been far too comfortable with the production‡consumption cycle, with simply throwing away anything “old.” But can we change our attitudes? What if waste weren’t simply waste? After all, it is we humans who define the term.


TecHome Technology is wedged between factories in Tainan’s An Ping Industrial Park. A gray truck stands outside the company’s offices, its sheet-metal exterior covered in a layer of cement paint. Lightly patterned, the paint is subtly different from the usual.

Kuo Wen-yi, TecHome’s owner, leads us up the stairs to the second floor of the company’s offices, where he shows us a large portrait of Che Guevara created using the same paint. Kuo gives the portrait, which he painted himself, a satisfied look and tells us, “This painting is very important to me because it represents a revolution.”

Transforming silt

Kuo’s business has its roots in the Agong­dian Reservoir in Kao­hsiung’s Yan­chao District. Geologically speaking, Taiwan is a young and fractured land. Heavy rainfall frequently washes large amounts of earth and gravel out of our fragile highlands and down into reservoirs like Agong­dian, where it accumulates and reduces their storage capacity.

The 4 million tons of silt that build up in Taiwan’s reservoirs every year are an ongoing headache for our water management agencies. When Kuo was pursuing his PhD in civil engineering at National Cheng Kung University more than a decade ago, the Council for Economic Planning and Develop­ment (now the National Development Council) asked his advisor, Huang Jong-shin, to research applications for the difficult-to-­dispose-of reservoir silt.

Huang’s team developed a method for reforming reservoir silt, turning it into a gas-permeable, water-resistant cement additive that also prevents efflorescence. These properties make it very useful in construction and renovation. Once Kuo finished his degree, he formed TecHome, NCKU’s first spin-off company, to sell the additive under the “Lotos” brand name.

Kuo admits that transitioning from R&D to running a company has not been easy, noting that building a market is tougher than developing a technology. In fact, it took the 13-year-old company seven years to turn its first profit. Asked why he didn’t just transfer the technology to another company and enjoy the fruits of his labor, he says: “I had to do it myself to maintain the brand’s spirit and ideals. Most companies are profit seeking. If they don’t make money on something within a few years, they pull out of the market.” Patting the portrait on the wall, he laughs, “That’s why I say this image is so important.”

Most Taiwanese have seen efflorescence in a home at some point. The surface breakdown that it can cause in cement walls is known as “wall cancer” in Taiwan. Modern construction uses a great deal of cement, which absorbs moisture more easily than it releases it. Taiwan’s warm, humid climate makes efflorescence common and has given rise to the belief that it cannot be treated. However, adding Lotos to the cement plaster used to surface a wall can completely resolve the problem.

In the company’s early days, Kuo planned to begin by selling to construction com­panies, not realizing that firms in traditional industries were very conservative, and that the larger the company, the less willing it would be to try something new. Forced to change course, he built an online sales platform and set his sights on the general public. He even ventured onto the front lines himself by filming educational videos and writing articles to answer consumers’ questions.

Branching into the arts

If you ask Kuo his secret to business success, he’ll tell you it’s really nothing special—he just insists on quality. He doesn’t like to stress that Lotos is a “circular ma­terial” because there is a perception that materials labeled as “circular” lack durability, and he doesn’t believe that applies to his product. “If you want consumers to have confidence in your products, you have to ensure their quality.”

TecHome has stuck to this philosophy, and ­developed a loyal customer base through the exceptional quality of its products. These customers have in turn expanded TecHome’s market via positive word-of-mouth on social media.

Nini-Mumu is a brand of household items made from cement. Founder Ray Wu had gotten involved with growing succulents, which led to exploration of the cement containers often used to pot them. Wu, who enjoys making things by hand, began experi­ment­ing with cement products from a number of companies before settling on Lotos.

Downtown Tainan’s Lotos Inside is a gathering place for a number of artists that support Lotos. By serving as both an arts and crafts studio and a retail space, Lotos Inside is introducing people to a different side of cement.

One of the walls inside the space is finished with Lotos plaster, giving it an industrial aesthetic. Nini-Mumu products made from Lotos Mordel 3D cement are on display in the product area, and include gray, black and white flower vases, tea trays, and soap dishes. Decorated with interesting patterns and textures using Wu’s own techniques, they imbue cement products with a surprising wabi-sabi aesthetic.

Transforming agricultural waste

As with TecHome, the impetus for a move into the circular economy is almost always a volume of waste so large it instills a sense of helplessness.

Tainan’s rural Guantian District grows water caltrops. When we visit at the tail end of the production season, several senior citizens are sitting in a circle, peeling the aquatic vegetable. Adept at their task, each quickly accumulates a hillock of water-caltrop skins at their side.

Visitors are drawn to such pastoral scenes, but their charm belies a longstanding ­problem for locals. 

Guantian produces about 6,500 tons of water caltrops per year, some 500 tons of which remain in the community. These are the peeled skins, and they are a major trash headache. In the past, farmers dumped them into nearby ponds and piled them beside roads and paddy-field embankments. But over time, these dumping areas began to stink and breed mosquitoes. Farmers also resorted to burning the peels in their fields after the harvest season was over, but this created air pollution. When confronted about the burning, farmers often shrugged their shoulders and claimed ignorance about who was doing it.

Finding a way forward

Yen Neng-teng arrived in Guantian five years ago to take over as head of the district administration. When he observed the long-term problem, his first thought was to process the water-caltrop skins into biochar.

When we enter Yen’s office, we notice that it isn’t quite what we expected. The bottles and cans on the back of a desk contain the results of Yen’s experiments with various brands of biochar. The hydroponic plants around the room are also part of his experiments. 

A graduate of the Mechanical Engineering Department at NCKU, he has the factfinding orientation of someone trained in the sciences and regularly conducts experiments on water-­caltrop charcoal. He picks up a Chinese fan palm (Livistona chinensis), its twisted roots plainly visible in the clear glass container, and explains that the small layer of water-­caltrop-skin char at the bottom of the pot is highly adsorbent. That attribute of the char has enabled the water in the container to remain unchanged for years while remaining perfectly clear.

“I hope our communities can grow like this plant, from here to here,” says Yen, pointing first at the layer of char and then at the lush green fronds.

He explains that the government’s past attempts at community development tended towards one-off events or programs, the effects of which didn’t last. Nowadays, efforts have shifted to “placemaking.” Yen sees high-value-added water-caltrop biochar as an example of the latter and hopes it will set the community’s economy on a sustainable footing.

Broad cooperation

With Yen pushing, the quiet community began to get busy. Now, when the water-­caltrop season arrives, the local seniors peel and sun-dry the skins, which are then collected and sent to a kiln. Over the last few years, the “recycling” rate of the skins has risen to 60%.

Lin Hong-ping, a distinguished professor in the Department of Chemistry at NCKU, developed the core technology for making char from water-­caltrop peels. He explains that the skins are dried in the sun until their moisture content declines to 10%, and they are then loaded into barrel-­shaped steel furnaces and burned at 1000°C for 30 minutes, then quickly cooled by spraying water into the furnaces. This process turns the originally reddish skins to shiny black charcoal.

Lin notes that producers of water-caltrop char have to pay attention to several factors, including the water content of the peels, the dimensions of the furnace’s primary and secondary air inlet holes, the width of the chimney, and the duration of the burn, all of which must be precisely controlled. He notes further that it took a year and a half of experimentation to determine the values that yielded the best results. 

Lin points out that the high lignin content of water-caltrop skins makes them a good source material for biochar. They also have a high “specific surface area” (SSA) after burning, with just one gram of water-caltrop char having the same surface area as half a basket­ball court. This makes the char very adsorb­ent, enabling it to soak up moisture and odors and improve the quality of soils and water. He says that testing has shown that the levels of dioxins and polycyclic aromatic hydrocarbons in the char fall within inter­national standards, meaning that it is very safe.

As a model for placemaking and a producer of water-caltrop biochar, Guantian has become a campus of sorts. Faculty and students from NCKU and other important Southern Taiwan colleges and universities, including Kun Shan University and Chia Nan University of Pharmacy and Science, have visited and used their particular resources to assist with the community’s development and to learn to participate in community services.

Such forward-looking development has attracted young entrepreneurs who are further­ing the commercialization of “waste” materials, and proving that you can indeed turn trash into treasure.

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文‧蘇俐穎 圖‧林格立


































他強調,菱殼木質素含量相當高,是製作生物炭相當好的原料,燒製後的菱殼炭「比表面積」(specific surface area,物質的單位體積的表面積)相當高,才一公克的菱殼炭就有半個籃球場大,因此吸附效果相當好,除了吸濕、除臭,還可以用來改善土壤與水質,他也相當重視產品的安全性,包含戴奧辛、多環芳香烴含量,送驗以後均符合國際檢驗標準。






文・蘇俐穎 写真・林格立 翻訳・山口 雪菜






































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