Can food waste become compost within 48 hours (or less)?

Photo by Djim Loic on Unsplash

There are an increasing number of table top or industrial machines which claim to turn, usually, food waste into compost within 24 to 48 hours.

The claim, generally, is that Machine X will turn kitchen scraps into "compost" within 12/24/48 hours because of its unique processing system and proprietary blend of micro-organisms.

This is not possible. The UK food waste company, Tidy Planet have an extensive FAQ that deals with this issue. As does America's Green Mountain Technologies.

The output from these machines is not compost. Rather it is a dehydrated powder. If this is meant to be applied to plants or added into soil, this powder requires a secondary process (usually proper composting with other organic matter).

Compost is a natural process and involves the complex interaction between bacteria, fungi, insects, and minerals. In nature, the process of organic waste becoming compost (and then humus) can take weeks, months and even years.

In the composting process, organic waste goes through natural—which has been perfected over millennia by nature—stages: mesophylic to thermophilic to mesophylic to mineralisation.

This natural process can take anything between 10-20 days even under controlled conditions.

“Composting” is defined in the Waste Management Licensing (Scotland) Regulations 2011 (WMLR), as–

“the autothermic [i.e. self-heating] and thermophilic [i.e. 40-80°C] biological decomposition and stabilisation of biodegradable waste under controlled aerobic conditions that result in a stable sanitised material that can be applied to land for the benefit of agriculture, horticulture or ecological improvement”. (Source: Tidy Planet).

Green Mountain Technologies cite research conducted by Loyola Marymount University in the USA which concluded that:

"Ultimately, the study revealed that the unprocessed dehydrated food waste samples were not suitable as a soil amendment on LMU's campus. Rehydration of DFW produced large quantities of fungus, an outcome not acceptable on LMU's grounds. Although dehydrated, the material is not decomposed to a stable state. This is a key distinction. While dehydrating LMU's preconsumer food waste is a good first step towards sustainability, further processing of this material is needed before it is suitable to be used as a soil amendment or for another purpose."

Essentially then, "24 hour compost" is simply dehydrated organic (food) matter.

This is fine if you are looking to reduce volumes going to landfill. And are prepared to accept the significant amount of energy required to dehydrate large volumes of food waste fast. And also accept that this matrix needs secondary processing if it is going to be used as a soil amendment.

Like all things, good stuff take time. And good compost is not fast 'compost'.