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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 and Advantages

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.

  Delivered to Location Ingredient biomass Year Use of biochar and other processed materials
1 JA Kita-ibuki(Numata town office) Hokkaido Rice husk 1999 Soil conditioner and snow melting agent
2 Kitamura village office Hokkaido Rice husk 1999 Soil conditioner and snow melting agent
3 JA Bibai Hokkaido Rice husk 1999 Soil conditioner and snow melting agent
4 JA Urausu Hokkaido Rice husk 2000 Soil conditioner and snow melting agent
5 Irabu Island Okinawa Bagasse (sugar cane residue)  2000 Soil conditioner for sugar cane fields / Wood vinegar for agriculture
6 Tokyo University Tokyo Brewer’s grain 2000 Research
7 JA Ashikita Kumamoto Onion/mandarin orange residue 2001 Soil conditioner for onion fields
8 JA Kumamoto Uki Kumamoto Vegetable residue 2002 Mixed in compost, for farm house
9 Matsubara Chicken Farm Kagoshima Chicken manure 2002 Soil conditioner, for tea and vegetable fields
10 JA Kotonoumi Nagasaki Mandarin orange residue 2002 Soil conditioner, for mandarin orange fields
11 JA Sakuma Nagano Lettuce residue 2003 Sold to an agricultural soil production company
12 JA Ehime Taiki Ehime Compost 2003 Mixed in compost, to home centers
13 Anshan Yinzhu Cereals and Oils Liaoning, China Rice husk 2003 Heat insulator at iron works, etc.
14 Kasetsart University Bangkok, Thailand Wood chips, etc. 2003 Research
15 Ryuku University Okinawa Vegetable, etc. 2003 Research (Soil conditioner for sugar cane fields / Wood vinegar for agriculture)
16 JA Arida Wakayama Mandarin orange residue 2004 Soil conditioner
17 JA Dainagasaki Nagasaki Vegetable residue 2004 Soil conditioner, Moisture adjustor
18 Ogi town office Ooita Bark compost 2004 Mixed in compost
19 JA Amahigasi Ehime Rice husk 2004 To make high quality compost
20 Yatsuo town office Toyama Wood chips, pruning 2004 Soil conditioner
21 Sanwa Yuka Industrial Aichi Drying of oil-containing sludge 2004 Recycle of oil
22 Hokuren vegetable plant Ibaraki Vegetable residue (Onion, etc.) 2004 Soil conditioner
23 Iwate Welfare Federation Iwate Used paper diapers 2004 Deodorizer
24 Zhongsuotun Village, Anshan city Liaoning, China Rice husk 2005 Gasified fuel
25 H.C.Starck – V TECH Ltd. Tochigi Sludge 2005 Tantalum recovery
26 Meidensya Corporation Ishikawa Wood chips 2005 Research
27 Industrial Technology Research Institute Taiwan Bamboo 2005 Research
28 Miyako Island Okinawa Bagasse 2005 Soil conditioner
29 JA Kinosato Wakayama Pruned tree 2005 Soil conditioner
30 JA Nagamine Wakayama Mandarin orange residue 2005 Soil conditioner
31 Shibuya Kogyo Co.,Ltd. Ishikawa medical waste 2005 Research
32 Kureha Foods Co., Ltd. Toyama Tofu residue 2005 Drying, waste volume reduction
33 Kanuma City Government Tochigi Wood chips and sludge 2006 Soil conditioner
34 Osaki Town office Kagoshima Chicken manure 2006 Soil conditioner
35 Minami-Awaji City (3 sets) Hyogo Onion residue 2006 Soil conditioner
36 Miyako Island Research Center Okinawa Bagasse 2006 Gasified fuel
37 Tianjin(2 sets) China Rice husk, Raw cotton(Leaf, Stalk) 2006 Gasified fuel
38 Meidensya Corporation (Noto Forestry Cooperative) Ishikawa Wood chips 2006 NEDO trial
39 JA Fuyo Korea Rice husk 2006 Soil conditioner
40 Hokkaido University Hokkaido Wood chips 2006 Research
41 Centrair (Central Japan International Airport) Aichi Garbage 2006 Fuel
42 Minami-Awaji City (2 sets) Hyogo Onion residue 2007 Soil improvement
43 Miyako Island Bio-Eco System Okinawa Bagasse 2007 Research
44 Tokyo University Tokyo Bio-mass 2007 Research
45 JA Ishikawa kahoku Ishikawa Rice husk 2007 Soil improvement
46 A certain place Japan Wood etc. 2007 Research
47 Institute of Industrial Science, the University of Tokyo Nagano Biomass 2007 Research
48 Godo Crarification Center Gifu sewage sludge 2008 Soil improvement
49 Hida City Oita Wood etc. 2008 Materials
50 Tsugaru National Land Preservation Co., LTD. Aomori Wood etc. 2008 Materials
51 Hirosaki University Aomori Wood etc. 2008 Research
52 Kyo maron Ibaraki Prune residue 2008 Materials
53 A certain maker Japan Wood chips 2009 Electrical generation
54 Godo Crarification Center Gifu sewage sludge 2009 Soil improvement
55 NORA Bio-mas Eco Fuel Noto Ishikawa Wood chips 2009 Make pellets
56 Jisyoen Social Welfare Co. Ishikawa Wood chips 2010 Supplying hot water
57 Ryukyu University Okinawa Wood chips, fruits seed 2010 Research
58 A certain maker Japan Wood chips 2010 Electrical generation
59 A certain factory Shanxi, China Kanaf 2010 Industrial material
60 Sanko Kogyo Co., Ltd. Okayama Trimming tree 2010 Waste volume reduction
61 Anshan Minghe Environmental Protection Technology Co., Ltd. China Sunflower seed 2011 Waste volume reduction
62 Minkan Inasaku Kenkyujo Tochigi Rice husk 2011 Research
63 Fukue Einou Limited private company Gifu Momigalite (solid fuel made of rice husk) 2012 Selling
64 Vietnam National University and HoChiMinh City University of Technology Vietnam Biomass 2012 Research
65 CSIC ENVIRONMENTAL CONSTRUCTION, INC. China Sludge residue 2012 Waste volume reduction
66 Japan wood energy Co., Ltd. Tokyo Biomass 2012 Waste volume reduction
67 A certain maker Fukui Rice husk 2012 Waste volume reduction
68 Tosanshou Co., Ltd. Akita Wood chips 2012 Bio-oil
69 A certain maker Yamagata Wood chips 2012 Gasification power generation
70 Federation of forestry cooperatives (Ishikawa) Ishikawa Pellet 2012 Heating
71 Nihonkaigas Co.,Ltd. Ishikawa Food waste 2012 Fermentation(for research)
72 Tokyo University Fukushima Soil 2013 Decontamination
73 Kanazawa University Ishikawa Sludge 2013 Fermentation(for research)
74 Nakanoto Ishikawa Sludge 2013 Fermentation(for research)
75 China China Livestock 2013 Waste treatment
76 Neonite Corporation Fukushima Wood chips 2014 Power generation
77 Chicken farm Tochigi Chicken manure 2014 Fertilizer
78 Tanakakensetu Co., Ltd. Ishikawa Oyster shell 2014 Calcined lime for construction material
79 Petrol China China Oil-containing sludge 2015 Oil collection
80 Tonookousan Corporation Fukushima Wood chips 2015 Bio-oil collection
81 Hytem Co., ltd Ishikawa Chicken manure 2015 Power generation
82 BiogasLABO Ishikawa Sludge 2015 Fermentation(for analysis)
83 Japan wood energy Co., Ltd. Yamanashi Woody material 2015 Power generation
84 A certain company Norway Wood chips & fish residue 2015 Waste treatment
85 Wood processing company Ishikawa Biomass boiler 2015 Firewood drying
86 Tokyo University Chiba Wood chip 2015 Power generation(for research)
87 Tokyo Institute of Technology Kanagawa Wood chip 2016 Power generation(for research)
88 Kyushu University Vietnam Sludge 2016 Fermentation & carbonization(for research)
89 Anshan Minghe Environmental Protection Technology Co., Ltd. China Rice husk 2016 Heat insulating material
90 A certain maker Kagoshima Bone black 2016 Regeneration of activated carbon


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)


Contact person

Department: Marketing
Position: International Program Manager
Name: Mr. Takeo TOKUNARI
E-mail : [email protected] 
Corporate website:

Technology owners:

Meiwa Co., Ltd.