Green highlighted words indicate definitions and links to the glossary section.
Commercial vendors are promoting food waste dehydrators to California businesses and institutions that generate large quantities of food waste, such as restaurants, hotels, grocery stores, universities, and prisons. This webpage provides information that may be helpful when evaluating whether this type of technology is appropriate for your facility.
- Food waste dehydrators operate with electricity and are typically installed in commercial settings where food waste can be separated from other waste and placed into a dehydrator located near the food preparation area.
- Commercial food waste dehydrators should not be confused with home dehydrators, which are used for drying fruits, vegetables, and meat for consumption.
- Food waste dehydrators shred food waste and use heat to evaporate moisture. The residual is dried food waste, which is a pulpy mass dry to the touch.
- Dried food waste is not compost or a compost product. Food waste dehydrators do not use a biological process to reduce pathogens and decompose food waste into a stable substance.
- If it becomes wet again, the dried food waste can re-absorb water. At this point it will have similar characteristics to unprocessed food waste, meaning it can attract vectors and create odor.
Proper Handling of Dehydrated Food Waste
State regulations do not define dehydrated food waste any differently than unprocessed food waste; it is considered a solid waste and must be handled as such. State regulations require solid waste to be removed from businesses and residences at least once each week and taken to a facility designed and permitted to handle the waste. In addition to state requirements, solid waste handling may also be subject to local ordinances. Anyone using a food dehydrator should check with their local (city or county) government to determine whether there are local rules regarding solid waste handling and transport that must be considered.
Compost that has been pathogen reduced and tested, as required by state regulations, can be used as a soil amendment. Incorporating uncomposted food waste into soil, or using it as mulch, is disposal. Only operations that meet all local and state requirements can legally dispose of solid waste.
Food waste—including dehydrated food waste—can be a feedstock at a compost facility. In small amounts, it can also be composted where it is produced. For specific requirements for on-site composting that does not require a permit, see California Code of Regulations, Title 14, section 17855.
Dehydrated food waste may potentially have value as an ingredient for animal feed or fertilizer. The California Department of Food and Agriculture (CDFA) regulates the manufacture and distribution of effective and safe animal feed and fertilizer. Anyone proposing to sell dehydrated food waste as a feed or as a fertilizer must first get approval from CDFA.
Dehydrating food waste reduces weight and volume, which can lead to reduced hauling and disposal costs. If the material is kept dry, dehydrators may also help reduce odors and vectors associated with handling and storing food waste.
Few studies have been performed on dehydrated food waste. One such study conducted at Loyola Marymount University in 2010 concluded the following:
- Unprocessed dehydrated food waste samples were not suitable as a soil amendment on the Loyola Marymount University campus.
- Rehydration produced large quantities of fungus. Although dehydrated, the material was not decomposed to a stable state.
- Further processing of the material is needed before it would be suitable as a soil amendment.
For More Information
Samples of dehydrated food waste end product from Loyola Marymount University in 2010. Select each image for larger view.
- BioCycle Magazine: Analysis of Biodigesters and Dehydrators to Manage Organics On-Site Part 1 by Zoe Neale.
- BioCycle Magazine: Biodigesters and Dehydrators – Operational Experiences Part 2 by Zoe Neale.
- The Composting Collaborative Pretreatment Directory for information on wet and dry Food Waste pretreatment systems.
- Compostable Materials Handling Operations and Facilities Regulatory Requirements
- Food Waste Liquefiers