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Meiwa Co., Ltd.

Agriculture: Converting Organic Waste into Charcoal

Conversion of Organic Waste into Charcoal: An Agricultural Focus


Meiwa Co., Ltd. offers a solution to converting organic waste into charcoal. A biomass carbonization plant is essentially a waste recycling plant that converts organic matter into charcoal (referred to as biochar) for fuel, soil conditioner or fertilizer*. Materials that can be processed include food waste, sewage sludge, animal waste, etc.

Usually, it is difficult to carbonize wet biomass because it requires energy and cost to dry it out first. However Meiwa’s technology makes it possible to process by utilizing waste heat from combusting syngas from carbonization chamber and patented carbonization method with dry biomass.

*See another page of UNIDO’s Environmental Technology Database for more details:

Major Features

I. Versatility

While common methods can only use dry materials, the Meiwa’s technology can process both wet and dry materials. Examples of wet materials include food waste, animal waste, human waste, and sludge. Dry materials include bamboo, residual wood, saw dust and rice husk.

Meiwa has installed over 70 biomass carbonization plants for processing various ingredients.

II. Energy Efficiency and Cost Efficiency

An integrated drying unit utilizes waste heat from the carbonization chamber. This results in energy- and cost-efficient operation of the carbonization plant, as (with the exception of the ignition process) no fossil fuel is required.

III. Quick Process

Compared with other organic waste processing methods, biomass carbonization is quicker with an output that is easier to sell. With composting, for instance, the fermentation process takes a long time, with a final output that is difficult to sell. Conversely, this carbonization plant can finish the process within one day and the output (biochar) can be sold as natural fertilizer, soil conditioner or fuel, diversifying the inventory risk.

IV. High Processing Capacity

The process can produce between 50kg/d and 25t/d, which can be adjusted based on the client’s needs. The yield is between 1/3 and 1/4 of raw material as charcoal.

Meiwa Co., Ltd. has delivered more than 70 biomass carbonization plants since 1999, 15 of which went to foreign countries such as China and Vietnam. About 85% of them were large scale plants, while the rest were small- to middle-scale plants (batch type).

Technology data

Conceivable applications
Simply put, biomass carbonization plant is a waste recycling plant that can convert almost anything organic into charcoal (called biochar). Processable materials include sludge, human waste, chicken manure, scrap wood, agricultural residue, food waste and water hyacinth among others. As biochar can work as a natural fertilizer, soil conditioner, fuel etc., Meiwa’s biomass carbonization technology provides solutions to waste management and agriculture, environment and/or energy at the same time.

Competitive Advantage
Competitive advantage compared to products of competing enterprise

(1) Advantages over competitors’ carbonization plants

Various processable materials

Based on our experience of installing more than 70 biomass carbonization plants, Meiwa has a market-proven method of processing both wet and dry materials, while typical competitors can only deal with dry materials.

Energy and cost efficient operation

Meiwa can use an integrated drying unit that utilizes waste heat from carbonization chamber as well as dry biomass for energy- and cost-efficient operation of the carbonization plant. Except for the ignition process, it does not require any fossil fuel.

(2) Compare to other organic waste processing method

Composting is another common technology for organic waste recycling. However, it is often a problem that the fermentation process requires a long time and the final output is hard to sell for value. Compared to this, our carbonization plant can complete the process within a day and the output is easier to sell (as powerful natural fertilizer/soil conditioner or fuel).

Processable materials:

Both wet biomass (e.g. sludge, human waste, and animal waste, water hyacinth, food waste etc.) and dry biomass (saw dust, rice husk, residual wood, bamboo, etc.)

Output products:

Charcoal (biochar) that can be used as a natural fertilizer, soil conditioner and/or fuel

Processing capacity:

From 50kg/d to 25t/d, adjustable upon client’s request

Yield of output products:

About 1/3~1/4 of raw material (as charcoal)

Optional unit: Drying unit, power generation unit*, wood vinegar harvesting unit*, desulfurization unit, etc. *ingredient-selective

Technical maturity / Past record of introduction
Since 1999, we have delivered more than 70 biomass carbonization plants. 15 of those were sold to foreign countries (China, Vietnam, Norway, Korea, Taiwan and Thailand). Approximately 85% of them were large scale plants, while 15% were small- to middle-scale batch plants. Ingredients range from rice husk, bagasse (sugar cane residue), fruits and vegetables, sludge, woody biomass, chicken manure, food waste to infected animals, oyster shell, mobile phone and diaper. We also have related biomass processing technologies, such as methane fermentation, biodigester and biomass power generation plant.

Conceivable risk
1. Intellectual property-related risks

Meiwa’s patent covers a specific method of plant operation. Therefore, physically copying the machine alone will not be competitive as such operation will likely require high running costs. Meiwa also supplies core parts from Japan.

2. Human resources management

Meiwa is interested in partnering with the local private sector that wishes to grow business as an agent. Meiwa will make every effort to manage human resources through incentivizing partners by actual sales performance and regularly having online/offline communication.

3. Finding right partners in local private and public sectors

To avoid fraud and other risks with inappropriate partners, Meiwa will first try to meet potential partners introduced by credible parties, such as international organizations, aid agencies, embassies, etc. as well as the ones attending high-level networking events such as TICAD. Meiwa will inquire the business record of foreign companies and project experience with the public sector. Meiwa does not intend to make any exclusive agreements.

Information on patent related to this technology
Patent No. 5636527
Patent No. 5887627
(both in Japan)


English, Japanese

Company Data

Company Name
Meiwa Co., Ltd.
3-8-1, Minato, Kanazawa, Ishikawa 920-0211 Japan
The Type of business
A technology-oriented Japanese company that develops biomass carbonization plants (a plant to convert almost anything organic into charcoal for agricultural or energy use). Examples of processable biomass include food waste, agricultural residue, human waste, animal waste, sludge and water hyacinth among others.
JPY 65 million (as of 2 December 2016)
Number of enployee
49 (as of 2 December 2016)
15 March 1964


Contact person
Department: Marketing
Position: International Program Manager
Name: Mr. Takeo Tokunari

※This innovation seed information is reprinted with permission from UNIDO ITPO Tokyo’s STePP website.

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