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Composting Basics

The science and engineering of the compost process

What exactly is composting? We might start by considering the definition presented by Haug (1993) which reads:

"Composting is the biological decomposition and stabilization of organic substrates, under conditions that allow development of thermophilic temperatures as a result of biologically produced heat, to produce a final product that is stable, free of pathogens and plant seeds, and can be beneficially applied to land."

In addition, the description of composting as one of a group of "high solids aerobic decomposition" processes (VanderGhenyst et al., 1997) provides a very useful perspective, especially from a scientific and engineering point of view. Noting that both definitions refer to aerobic composting only, we will adopt that distinction here.

Composting here means aerobic composting only. We will not be covering the anaerobic, biogas producing, processes and technologies which are sometimes included under the composting umbrella.

Getting started:

There are many excellent resources available to get you started on this topic so we will point the way, rather than reproduce extensive information available elsewhere.

One excellent introduction to the basic principles of composting is provided by Cornell University on their Cornell Composting web site. We highly recommend this site to everyone from casual home composters to commercial operators for an opportunity to learn or refresh the fundamentals of composting process.

The "On-farm composting handbook" provides a particularly useful coverage of the basic principles, plus good chapters on equipment, operational and product quality issues. This book can be ordered directly from NRAES at Cornell University. Other books plus videos are also listed in the Cornell site.

If you want to get right into the science of composting, explore some of the engineering aspects and look at a mathematical model then The Practical Handbook of Compost Engineering by Roger T. Haug is highly recommended.

For additional material see our Resources page.

References:

Haug, RT. (1993). The practical handbook of Compost Engineering. Lewis Publishers, Florida, USA.

VanderGheynst, JS., Gossett, JM., Walker, LP. (1997) High-solids aerobic decomposition: Pilot-scale reactor development and experimentation. Process Biochemistry 32 (5) 361-375.

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