In July, BioCycle published a guide to pretreatment of on-site food waste equipment and systems. The article describes three broad categories of equipment:

• Dehydrators utilize thermal processes to evaporate the liquid present in food waste.
• Liquefiers use water and enzymes/microbes to reduce the biochemical oxygen demand (BOD) and create wastewater that is usually discharged to the municipal sewer.
• In-vessel “accelerated composting” units process food waste over 4-7 days to reduce pathogens and vector attraction.

These systems pretreat food waste through biologic or thermal means. All require additional management through either curing the dehydrated biomass or compost to biologically stabilize it, or treating the liquefied product at a municipal wastewater treatment plant.

Businesses considering investing in an on-site system should be aware of the following requirements and constraints of these systems:

• Dehydrators and liquefiers require power hook-ups.
• Some systems can be fed either continuously, while others operate in cycles/batches.
• Dehydrators generate wastewater which will have to be managed.
• Dehydrated material, if exposed to water, can attract vectors and create odor.
• Wastewater from liquefiers needs to meet the discharge limits set by the municipal wastewater treatment plant.
• In-vessel accelerated composters require an additive such as sawdust.

RecyclingWorks in Massachusetts offers a directory of On-Site Systems for Managing Food Waste. This tool provides an overview of technologies that process food waste, including dehydrators, liquefies, composters, and anaerobic digesters. RecyclingWorks obtained information in this document from the manufacturers and distributors of these technologies.

RecyclingWorks assists businesses and institutions with recycling, reuse, and food waste diversion. To speak to a recycling expert, call our hotline: (888) 254-5525 or email us at info@recyclingworksma.com.