Low-temperature drying of organic waste for upcycling / Test cases / Waste drying, Waste dryer

■ Low-temperature drying of organic waste for upcycling / KENKI DRYER



KENKI DRYER, which uses low-temperature indirect steam drying, is suitable for drying organic waste in factories; the KENKI DRYER can smoothly dry even organic waste with high moisture content, which is difficult to dry due to its adhesive stickiness. This technology has been patented worldwide and is unique and different from other steam indirect dryers.

The advantages of KENKI DRYER include
Drying at low temperatures reduces changes in the composition of the materials to be dried, enabling their use as recycled or upcycled products.
As steam is used as the heat source, decarbonization drying is possible by using an electric boiler or surplus steam.
Low component wear and tear, easy and inexpensive maintenance.
As a continuous drying unit, it is easy to manage the operation and can be operated unattended 24 hours a day.

Drying organic waste reduces its weight and the amount of waste material produced. The KENKI DRYER can contribute to environmental protection and decarbonization.

Patented in: Japan, Taiwan, USA, France, Germany, UK, Switzerland and Canada.


By rotating the organic waste generated during the production of products in factories, it is possible to use the waste as an upcycled product since there is little change in the composition after drying. KENKI DRYER is an indirect drying system that uses steam as a heat source at low temperatures, so there is little change in the composition of the dried materials after drying, and they can be fully used as recycled or upcycled products.

When organic waste is left in a high-moisture state, decomposition is caused by the activity of microorganisms (especially bacteria and molds) contained in the organic waste. These microorganisms use the moisture and nutrients contained in the organic waste to reproduce, producing gases and odors in the process, and the growth of the microorganisms causes decomposition and the development of odors and pathogens. Drying is an effective way to solve these problems.

However, many organic wastes are difficult to dry due to their strong adhesion and stickiness, and some other types of dryers may not discharge sludge due to clogging inside the dryer during drying. KENKI DRYER can easily and smoothly dry even objects with high moisture content that are difficult to dry due to their strong adhesion. KENKI DRYER’s unique, world-patented mechanism allows even the most adhesive and sticky organic wastes with high water content to be dried smoothly without clogging the dryer.

KENKI DRYER, with 11 patents in 8 countries, is an indirect steam dryer, but it is a completely unique product, different in structure from other similar indirect steam dryers. Direct-fired dryers, such as burners, emit carbon dioxide from the dryer, which is against the times in terms of environmental protection and decarbonization, and drying at high temperatures means high fuel costs, rapid wear of parts and high maintenance costs. The KENKI DEYER uses steam as a heat source, but its high drying heat efficiency means that the amount of steam used is low, so you can use the steam you currently use, and if you use excess steam, there is no fuel cost, and the dryer emits no carbon dioxide during the drying process, enabling decarbonized drying. Alternatively, by installing an electric boiler, no greenhouse gases or CO2 emissions are produced during the drying process.

The dryer’s blades rotate at a very slow speed of 5 rpm or less, which means that wear on parts is minimal and maintenance is easy and inexpensive. KENKI DRYER is a continuous dryer, not a batch dryer that stores materials to be dried. Therefore, operation is simple and unmanned operation is possible 24 hours a day.

Drying organic waste to reduce the weight and volume of waste materials can contribute to environmental protection and decarbonization by reducing the cost of industrial waste, which is rising due to the recent trucking problem in 2024, and by reducing the number of trucks transporting waste, thereby reducing carbon dioxide emissions.

KENKI DRYER, which can dry sticky and adhesive materials that cannot be dried anywhere else, is an epoch-making dryer with a total of 11 patents (2 in Japan and 9 in 7 foreign countries). Please consider KENKI DRYER for your high moisture content organic waste dryer, sludge dryer, slurry dryer, methane fermentation digested liquid dryer, and waste recycling dryer.
KENKI DRYER has been granted 11 patents in 8 countries (Japan, Taiwan, USA, France, Germany, UK, Switzerland, Canada).





organic waste upcycling drying kenki dryer waste dryer 17.6.2024


KENKI DRYER sludge drying slurry drying waste drying top 01



■ Reasons for drying organic waste


There are three main reasons for drying organic waste

1. Prevention of decomposition

If organic waste is left in a high moisture state, it can decompose due to microbial growth, causing foul odors and pathogens. Drying is an effective way to solve these problems.

Drying reduces the water activity of organic waste. Water activity is an indicator of the amount of water available to microorganisms, and generally speaking, microbial growth is inhibited when water activity falls below 0.6.

Specifically, the following effects can be expected

・Inhibition of microbial growth: Decreased water activity inhibits the growth of microorganisms such as bacteria and molds that cause spoilage.
・Decrease in enzyme activity: Many enzymes are activated in water, but drying inhibits their activity and slows the decomposition of organic matter.
・Inhibition of chemical reactions: Many of the chemical reactions involved in decomposition require water, and drying inhibits these reactions.

2. volume and weight reduction

Drying organic waste can significantly reduce its volume and weight.

For example, the moisture content of food waste is approximately 60-80%, but drying can reduce the moisture content to less than 10%. This means a reduction of approximately one sixth in volume and one quarter in weight.

This helps to reduce the cost of waste disposal and improve the efficiency of transportation and storage.

3. resource recovery

Dried organic waste can be used for several purposes

Fuel: The dried material itself can be used as fuel or converted to biogas for use as fuel.
Fertilizer: The dried organic waste can be composted or used as a soil amendment.
Feed: Can be used as livestock feed.
Other: Can be used as a raw material for paper, fiber, plastics, etc.

Thus, drying organic waste offers a variety of benefits, including reduced environmental impact, cost savings, and resource recovery.





fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy but has since also been applied to other sources of heat energy, such as nuclear energy (via nuclear fission and nuclear fusion).

Source:Wiki Fuel




Compost is a mixture of ingredients used as plant fertilizer and to improve soil’s physical, chemical, and biological properties. It is commonly prepared by decomposing plant and food waste, recycling organic materials, and manure. The resulting mixture is rich in plant nutrients and beneficial organisms, such as bacteria, protozoa, nematodes, and fungi. Compost improves soil fertility in gardens, landscaping, horticulture, urban agriculture, and organic farming, reducing dependency on commercial chemical fertilizers. The benefits of compost include providing nutrients to crops as fertilizer, acting as a soil conditioner, increasing the humus or humic acid contents of the soil, and introducing beneficial microbes that help to suppress pathogens in the soil and reduce soil-borne diseases.

Source:Wiki Compost




fertilizer (American English) or fertiliser (British English) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Many sources of fertilizer exist, both natural and industrially produced. For most modern agricultural practices, fertilization focuses on three main macro nutrients: nitrogen (N), phosphorus (P), and potassium (K) with occasional addition of supplements like rock flour for micronutrients. Farmers apply these fertilizers in a variety of ways: through dry or pelletized or liquid application processes, using large agricultural equipment or hand-tool methods.

Source:Wiki Fertilizer


The three primary elements of fertilizer


The three primary elements of fertilizer, essential for plant growth and commonly referred to as macronutrients in the context of plant nutrition, are:

Nitrogen (N):
Function: Promotes leaf and stem growth, as it is a crucial component of chlorophyll, the compound that plants use in photosynthesis to convert sunlight into energy. Nitrogen is also a key part of amino acids, the building blocks of proteins.
Deficiency Symptoms: Yellowing of leaves (chlorosis), stunted growth, and poor yield.

Phosphorus (P):
Function: Essential for energy transfer and storage in plants, as it is a component of ATP (adenosine triphosphate). Phosphorus also plays a vital role in root development, flowering, and seed production.
Deficiency Symptoms: Dark green or purplish leaves, delayed maturity, and poor root development.

Potassium (K):
Function: Regulates various metabolic activities in plants, including photosynthesis, protein synthesis, and water regulation. Potassium is also important for improving disease resistance and overall plant health.
Deficiency Symptoms: Leaf edges may turn yellow or brown (scorching), weak stems, and reduced resistance to drought and diseases.
Fertilizers are often labeled with an N-P-K ratio, which indicates the relative proportions of these three essential nutrients. For example, a fertilizer labeled as 10-20-10 contains 10% nitrogen, 20% phosphorus, and 10% potassium.



KENKI DRYER sludge drying slurry drying waste drying top 02


Woman illustration organic waste drying kenki dryer organic waste drying 17.06.2024



■ Low-temperature drying of organic waste for upcycling / Test cases





■ Low-temperature drying of organic waste for upcycling / Test result


  • Material to be dry: Organic waste
  • Purpose of drying: Upcycling, Reducing industrial waste cost and amount
  • Moisture content: 73.4%W.B. before drying, 3.7%W.B. after drying
  • Requirements for dryer: To prevent clogging inside the dryer caused by the stickiness and adhesiveness. Automated continuous operation with no operator attended.
    Machine cost can be recovered in short term.
  • Test result: OK


organic waste drying before after kenki dryer 17.6.2024


Waste drying

Competitive comparison


■ Self-cleaning screw / Steam Heated Twin Screw Technology
( SHTS technology )


One of the International Patented Technology that KENKI DRYER has is a self-cleaning structure called Steam Heated Twin Screw technology (SHTS technology). No matter how materials are sticky, adhesive and viscous is, they can be dried without clogging inside of the dryer because of this unique structure that no other products has.
For example, even materials stuck to the blades of one screw, blades of the other screw in the dryer’s body forcibly peels the materials off as they rotate. Since the blades rotate by peeling the material off each other, any sticky, adhesive and viscous material does not adhere to the blade, and the blades continue rotating, peeling, agitating and heating material without stopping while they carries material further. Also, since surface of blades are always renewed and kept clean, heat near the blades is not blocked and it is conducted directly into the materials.

Self-cleaning screw


■ Product characteristics

KENKI DRYER has three main characteristics. They are 1) Any materials can be dried as expected including sticky, adhesive and viscous materials and raw material slurry that no other company can deal with, 2) dried material can by recycled or utilized as raw materials because of its low-temperature drying method, and 3) there is no need to assign operator since its continuous operating system makes 24 hours unattended operation possible.



■ Drying process


The unique and original drying mechanism of KENKI DRYER is also International Patented Technology. Because 4 drying mechanisms which are crashing drying, agitation drying, circulation drying and indirect drying work simultaneously and add heat to material being dried repeatedly and continuously, inner part of the material is dried thoroughly and quality of discharged material after drying is stable. This series of drying mechanisms prevents agglomeration which causes insufficient drying from feeding process of the material into the dryer until discharging process after drying completed. Various ingenuities to conduct heat surely into inner part of the materials are exercised and stable heating and drying are proceeded continuously.



■ Heat source, Saturated steam


Even KENKI DRYER uses only saturated steam as its heat source, it is outstanding in safety and hygiene point of view with its unique drying mechanism based on combined use of conductive heat transfer method and heated air method. Since steam is a stable heat source, quality of discharged material after drying is also stable and equable. Maximum allowed steam pressure is 0.7Mpa and adjustment of steam pressure, adjustment of drying temperature in other words, can be easily done. Saturated steam is commonly used in many factories so that it can be said as a familiar and handy heat source. In comparison with drying methods using burner or hot blasts, saturated steam method is an indirect drying applying heat exchange via pipes that steam is passing through, therefore, it hardly burns the materials and is outstanding in safety and hygiene point of view.

Heat source, Steam


Please consider KENKI DRYER for drying of sticky materials, adhesive materials and materials in liquid state that no other dryer can deal with.
Initial, running and maintenance costs are low because of its simple structure based on internationally patented technology.
For sludge drying, costs of our dryers are estimated to be retrieved within 2, 3 years by reducing industrial waste disposal cost.
For raw material slurry drying, laborious works of manual operation will be decreased significantly by replacing box shaped compartment tray dryer with our dryer
In case of organic wastes drying, the waste can be recycled as fuel, fertilizer, soil conditioner and feedstuff after being dried.


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