TOKYO - Small compost bins that turn kitchen scraps into soil with the help of microorganisms are finding a growing audience in Japan, driven by rising interest in sustainability and low-waste lifestyles.
Composting systems that do not require soil replacement and compact bag-type compost bins are making it easier for people to recycle food waste at home, even in apartments with limited space.
Growing interest in the Sustainable Development Goals (SDGs) has helped raise the profile of composting in Japan, leading to the opening of a specialty store and the publication of a book focused on compost-based living.
The United Nations-led SDGs call for action by all countries by 2030 in global partnership, covering 17 areas including tackling climate change, sustainable cities and communities, gender equality, and elimination of extreme poverty.
"I can even put in leftover frying oil and ramen broth. Watching the food waste disappear is incredibly satisfying," said a woman living in a fourth-floor apartment building in Tokyo's Suginami Ward.
The woman, who lives with one other person, said using a compost bin has dramatically reduced the amount of household waste she throws away. Every few days, she digs a small hole in the container, adds accumulated food scraps and mixes them into the soil.
She now only disposes of burnable garbage once every two weeks.
The composting system she uses is called "Kiero," a box-shaped container designed to decompose food waste using microorganisms in soil. The system is equipped with a transparent lid that allows sunlight through and ventilation gaps that help promote decomposition.
"The wooden texture is lovely, making it approachable for beginners," she said, adding that she has not experienced problems with odors or insects.
According to Nobuo Matsumoto, who invented the Kiero system, microorganisms break down food waste almost completely. Unlike some other composting methods, the amount of soil remains largely unchanged, meaning replacement is generally unnecessary if decomposition is progressing smoothly.
However, composting becomes less efficient during colder months, when lower temperatures slow microbial activity and reduce the amount of waste the system can process.
The growing popularity of composting has helped create a niche market for products tailored to urban consumers.
Tokyo-based specialty store Compost Friends stocks a range of compost bins designed for different household sizes and lifestyles. One of its products is a small Kiero made from recycled apple crates, intended for households of one or two people and priced at 16,500 yen ($104).
The shop also sells bag-type composters costing 6,600 yen that can be used to make compost in smaller spaces.
"The Kiero is popular because it's easy to use," said store owner Miwako Nishikawa. "For people who want something smaller and cheaper to start with, I usually recommend the bag-type version."
Local governments are also promoting the recycling of food waste as municipalities seek ways to reduce household garbage. The city of Nagoya, for example, has introduced a composting system using cardboard boxes on its website.
According to Nishikawa, many local governments subsidize the purchase of food waste processing equipment, including compost bins. But some municipalities only provide subsidies for electric processing machines, prompting calls for support to also include nonelectric composting systems viewed as more environmentally friendly.
Yuichiro Hattori, author of the book "Easy Compost Life," said composting encourages people to reconsider their relationship with waste. "Handling your own waste and making recycling part of everyday life can really change the way you live. It may look like a hassle at first, but I hope more people come to see how rewarding it can be."
