Dehydration Technology

Dehydrators are an enclosed container that uses electricity to heat and agitate the food waste materials, whilst a fan removes moisture laden air from the unit. The combination of heat, agitation and air flow enables rapid drying within around 24 hours.

Unlike composting, food waste can be processed without requiring complementary bulking materials to absorb excess moisture from high moisture content food waste. This makes dehydration technology easier to operate and requires a smaller area.

The benefit of rapid stabilisation of food waste by drying is to produce a material that is more readily stored and handled, and is significantly reduced in volume and weight. This reduces the costs of containment, transport, and the associated consumption of transport fuel.

Correct operation is required. Food wastes contain biological hazards associated with food and waterborne illness including bacteria, viruses, etc. These pathogenic organisms can cause disease and death, usually enteric diseases through direct human contact with the organism or through the ingestion or inhalation.

Check with your local authorities for any requirements when considering dehydration technology.

Dehydration Technology Listings

Guidance for selection & correct use

Correct operation of dehydration unists is required for safety. Food wastes contain biological hazards associated with food and waterborne illness including bacteria, viruses, etc. These pathogenic organisms can cause disease and death, usually enteric diseases through direct human contact with the organism or through the ingestion or inhalation.

Treatment technologies must manage these risks by pasteurising the material at sufficiently high temperature for a sufficient duration to destroy pathogens. In the composting process, heat is biologically generated from the release of energy in the food when it is consumed and metabolized by the compost microorganisms. The method and requirements for pasteurisation using dehydration are different.

The requirements for destruction of pathogens and minimising potential for regrowth via dehydration or drying, as validated by the US EPA are:

  • Material is dried by direct or indirect contact with hot gases [for sufficient time] to reduce the moisture content of the material to 10% or lower. Either the temperature of the material particles exceeds 80°C (176°F) or the wet bulb temperature of the gas in contact with the material exceeds 80°C (176°F) as it leaves the dryer.
  • The machines are required to be managed as a batch based system, with one batch fully processed and cleared from the chamber prior to loading any fresh materials to avoid cross contamination.

Food waste dehydrators have become common in Japan over the past decade as a consequence of their 2001 Food Recycling Law. There are a many commercial manufacturers and models available internationally, most claiming to produce “compost” within 24 hours, though it is technically incorrect to refer to the output material as compost in numerous jurisdictions. At that time the use of electricity from nuclear power plants to dry food waste was considered in Japan to have no greenhouse gas emission consequence, and some dehydrator appliances were (are) promoted as having “zero environmental impact”…

Regardless of your view of such claims, where the electricity consumed is generated from coal fired power plants, drying or dehydrating appliances offer a trade off between additional greenhouse gas emissions from manufacture and electricity consumption of a drying appliance versus reduced transport and impact from organic waste disposal to landfill.

Comparing dehydrators or drying units

One key performance measure for dehydrators is energy efficiency, as measured by the quantity of electricity consumed per quantity of food waste processed. Consider the following performance characteristics when comparing dehydration/drying units:

  • Does the machine heat food waste to > 80oC?
  • Does the machine include a mechanism for confirmation of temperature of the material in the unit (or the process gas exiting the unit)? How is this assessed?
  • Does the machine include a mechanism for confirmation of the moisture content of the dried material unit?
  • What quantity (kg) of food waste can the machine effectively dry to less than 10% moisture per day (think about your operational work flow - how long the will unit have to dry food waste material after the last material is deposited at the end of the day, until the unit is cleared the following day before additional fresh material is loaded)?
  • How much electricity (kWh) does the machine consume per kg of food dried at > 80oC to a moisture content of less than 10% ?

The ROU has assessed samples of the finished output materials from numerous installations in Australia as having moisture content ranging from 18% to 31% moisture. These installations are failing to meet the requirements for pasteurization due to inadequate management, or inappropriate size of dehydrator unit for the quantity and/or type of food waste being generated.

Dehydration units are not dump-and-forget rubbish bins, these units still require clean food waste input, and still require monitoring and correct management for safe operation.

Numerous dehydration technologies on the market operate at temperatures in the low to mid 40 – 45 ºC temperature range, and there is an incentive to operate at lower temperature in order to present lower power consumption figure per quantity of food waste processed. However, as most Salmonella serotypes, for example can grow over the temperature range 7 – 48 ºC this approach may pose health and safety risks. Consider the placement of dehydrator units and risk associated with the moist process air being blown from the unit.

That food waste has been processed via a dehydrator is therefore no guarantee that the material is safe to handle or use. Technologies must be selected, located and managed correctly to deliver safe and acceptable performance. Consequently some State EPAs consider the output product to be “waste”, and require it to be managed as such, allowing it to be used only as an input into a composting processes, or disposed of to landfill.

Check with your local authorities for any requirements when considering dehydration technology.

Standards & compliance

The requirements for destruction of pathogens via dehydration or drying are:

  • Material is dried by direct or indirect contact with hot gases [for sufficient time] to reduce the moisture content of the material to 10% or lower. Either the temperature of the material particles exceeds 80°C (176°F) or the wet bulb temperature of the gas in contact with the material exceeds 80°C (176°F) as it leaves the dryer.
  • The machines are required to be managed as a batch based system, with one batch fully processed and cleared from the chamber prior to loading any fresh materials.

This requires a combination of QA procedures (loading, monitoring temperature, clearing out prior to loading fresh materials), and QC quality control (assessment of moisture content of material prior to discharge).

These criteria should be considered when selecting technology to ensure generic health and safety risk is managed.

80°C (176°F) is too high for biological decomposition, and it is incorrect to refer to dehydration processes as “composting”, which is a different biochemical process. The requirements for pasteurization via the composting process as specified in the AS4454 standard do not apply to drying or dehydration processes.

It is incorrect to refer to the output product as “compost” or to use the AS4454 Australian Standard for compost as a yardstick for the assessment of ineligible materials that are outside the scope of this standard, and that have not been considered in the specification and configuration of test methods contained in that standard.

GaiaRecycle


Functional description of the technology:
The GaiaRecycle food waste dehydrator is designed to heat and physically agitate food waste at temperature in excess of 80°C. The moisture content evaporates and is re-condensed as grey water which can be harvested for re-use.

The solid biomass remaining is roughly 10% of the original volume and is sterile. It can be used as an input into composting processes (or in some jurisdictions directly applied as a nutrient-rich soil amendment), or as a component of biomass fuel.

Performance benefits claimed of the technology:

  • simple to operate,
  • fast processing,
  • requires no additives and
  • is remarkably tolerant of contamination.

Types of food waste able to be processed:
All types of organic waste can be processed

Types of food waste NOT able to process:
The only exceptions are large items such as a leg-bone which present a risk of jamming the agitator. Should this occur, a motor overload would activate to stop the cycle

Model name / No. Weekly food waste processing capacity (kg/wk) Approximate dimensions (L x W x H)
GC-50 25 kg per batch, up to two batches per day. 1050 x 750 x 1213mm
GC-100 50 kg per batch, up to two batches per day. 1400 x 950 x 1291mm
GC-150 75 kg per batch, up to two batches per day. 1600 x 1000 x 1396mm
GC-300 150 kg per batch, up to two batches per day. 1820 x 1200 x 1580mm
GC-400 200 kg per batch, up to two batches per day. 2400 x 1500 x 1660mm
GC-600 300 kg per batch, up to two batches per day. 2600 x 1650 x 1800mm
GC-1200 600 kg per batch, up to two batches per day. 3300 x 1850 x 2040mm
GC-2000 1,000 kg per batch, up to two batches per day. 4200 x 2100 2300mm
Larger units Larger capacity units and gas versions available on request.  

Inputs/consumables required:
Electricity to drive motors, Electricity, gas or steam to provide energy for evaporating water content.

Additional or ancillary equipment required:
On larger capacity units a bin lifter for loading and an unloading auger are included.

Distributor:
Eco Guardians Pty Ltd
90 St Kilda Rd, St Kilda,
Victoria 3182, Australia

Australian distributor? Yes

Website: www.ecoguardians.com.au

Contact:
Doug Wilson
Phone: 0419 531 335 (within Australia)
Email: doug@ecoguardians.com.au

The information in this listing has been provided by the distributor of the listed technology and ROU has not assessed or verified information provided or claimed capabilities. Inclusion in this Directory does not represent endorsement or recommendation of then listed product. Refer to full disclaimer for the Directory.

Hun­gry Giant


Functional description of the technology:
The Hungry Giant® Food Waste Dry Decomposer (FWDD): Food and organic waste is placed in the FWDD through a top-loading door, or in larger machines a bin lifter lifts the bins with an auto loading hydraulic hopper door.

The waste is then macerated in a rotating drum to reduce its volume and enable greater levels of drying and dewatering. Through a robust reverse cycle heating system, waste is dried through a thermostatically controlled process – whereby the steam extracted from the organic matter is condensed and discharged from the unit.

The dried organic material is then dispensed in a tray at the base of the machine as a soil amendment.  Varied reduction of between 75 and 90% of input volume is to be expected. Cycle times vary based on moisture content of organic waste. Cycle times vary from 7 hours up to 24 hours depending on the size of the machine. Fluid condensate is discharged into trade waste or sewer.

Performance benefits claimed of the technology:

  • Rapid dehydration and volume reduction of over 80% over a 7 to 24 hour cycle.
  • Auto loading function with integrated bin lifters and hydraulic lids.
  • PLC controlled, with additional features and smarts to increase efficiency.
  • Auto maceration when loading – to displace food and increase machine capacity. Anti-jamming function- impeller reverse In the case of contamination.
  • Double discharge doors- faster discharge time.
  • Dry inert remnants can be stored on site if collections are sporadic.
  • Significantly reduced you waste bill and minimises the inconvenience of waste storage.
  • Reduced greenhouse gas emissions through was reduction and reduced transportation (methane from organic waste is 21 times more potent that carbon dioxide).
  • Organic waste is treated at temperatures of 85 degrees Celsius that kill pathogens and bacteria.
  • Fully sealed unit. Waste is batched and loaded. Then the machine is NOT opened again until the cycle has completed. The PLC goes through a cooling phase before turning off. There is no exposure to decomposing waste during the cycle.
  • Moisture sensors monitor the moisture levels every 2 minutes, so once optimum dehydration percentage is achieved, the machine stops. This is the most efficient way of operating a machine of this type.

Types of food waste able to be processed:
Most putrescible waste, Green waste ( florists etc.), some cardboard and napkins can go into a mixed load.

Types of food waste NOT able to process:
Large bones, oyster shells basically anything that is large and HARD which could damage the inner drum, and also anything which does not contain moisture, as there is no benefit to putting it into this type of dehydration machine if there is no moisture content.

Model name / No. Weekly food waste processing capacity (kg/wk) Approximate dimensions (L x W x H)
FWDD150L 150 litres per day
(80-120kg depending on moisture content)
852 x 1102 x 1220mm
FWDD300L 300 litres per day
(120-250kg depending on moisture content)
1100 x 2365 x 2290mm
FWDD500L 500 litres per day
(120-350kg depending on moisture content)
1354 x 2669 x 2490mm
FWDD1000L 1,000 litres per day
(120-700kg depending on moisture content)
1704 x 3069 x 2870mm
Custom sizes We can build in between these standard models, and up to much larger capacity machines. Even dual units with auger feeders.  

Inputs/consumables required:
No additives. No enzymes, no chemicals, just power, and plumbing.
Power: 3 phase, 5 pin, 4 core (amps vary depending on models).
Drainage is required to be connected to trade waste or sewer. We have utilities provider exemptions for connection to either. BOD tests etc. have been carried out (Sydney water) and litres per hour dilution are not of concern.

Additional or ancillary equipment required:
Bin lifter and safety cage come with machine price, magnetic coded safety switches, separate wall mounted control panels included. We have the option of adding a dewatering unit to further reduce waste (subject to utilities provider approval).

Distributor (manufacturer):
Resource Environmental Solutions Pty Ltd
50a Alexander Ave, Taren Point,
NSW 2229, Australia

Australian distributor? Yes

Website: www.wastemanagement.com.au or
www.hungrygiant.com.au  

Phone:
Phone: 1300 101 552 (within Australia)
Email: bookings@resourcenviro.com.au

The information in this listing has been provided by the distributor of the listed technology and ROU has not assessed or verified information provided or claimed capabilities. Inclusion in this Directory does not represent endorsement or recommendation of then listed product. Refer to full disclaimer for the Directory.

Submit another technology


The Manage Food Waste Directory is open for free listing of proven technologies for use by food service and property management enterprises and other organisations to reduce food waste and improve the recovery and reprocessing of food waste for beneficial use.

Please note we do not list technologies that are of a scale suited for household use such as home compost bins or worm farms, nor compost amendments/inoculants.

To list your technology on this Directory, complete and submit the Register Your Technology form.

Functional description of the technology:
Clear description of what the technology is for and how it works.

Performance benefits claimed of the technology:

  • Information content from supplier.
  • Information content from supplier.
  • Information content from supplier.
  • Information content from supplier.

Types of food waste able to be processed: All

Types of food waste NOT able to process: n/a

Model name / No. Weekly food waste processing capacity (kg/wk) Approximate dimensions (L x W x H in metres)
Model name xxx kg per day 0.0 x 0.0 x 0.0m
Model name xxx kg per day 0.0 x 0.0 x 0.0m
Model name xxx kg per day 0.0 x 0.0 x 0.0m

Inputs/consumables required:
Information content from supplier..

Additional or ancillary equipment required:
Information content from supplier.

Distributor (manufacturer):
Supplier business name
Supplier address line 1
Supplier address line 2

Australian distributor? Yes/No

Website: www.supplierURL.com/

Phone:
+61 supplier phone number (Australia)
Supplier international phone number (USA, UK, NZ, EU…)

The information in this listing has been provided by the distributor of the listed technology and ROU has not assessed or verified information provided or claimed capabilities. Inclusion in this Directory does not represent endorsement or recommendation of then listed product. Refer to full disclaimer for the Directory.

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Refer to the Technology Directory page for guidance on making best use of the listings on the MFW Directory.

Sponsors

The Recycled Organics Unit offers a range of services and training to assist enterprises to improve food waste management, including: site evaluation and review of current policies/practices, feasibility and implementation plans, operational support and staff training.

Disclaimer

NOTE: Contact details and general information for the technologies listed on the MFW Directory have been provided by the relevant supplier. All manufacturers are eligible for listing commercially available technologies on the MFW Directory however the MFW Directory cannot claim to include all technologies that may be available internationally. Except where explicitly stated, the ROU has not assessed or verified all claims made by suppliers, and suppliers are responsible for providing correct information.

The MFW Directory does not provide pricing details or configuration required for individual sites. Users of the MFW Directory can identify and shortlist technologies and must then directly contact listed suppliers to make their own enquiries to determine applicability of a product or technology to the specific requirements of your organisation and site. Inclusion of a technology or supplier on this Directory does not constitute a product endorsement or recommendations. Please refer to full disclaimer).