How does composting reduce the volume of organic waste?

Composting is a biological process that significantly reduces the volume of organic waste through the metabolic activity of microorganisms. As these microbes digest and break down organic materials under controlled aerobic conditions, they convert the waste into a stabilized product known as compost or humus.1

In the context of solid-waste management, this process can reduce the volume of organic refuse by as much as 50 percent. When utilizing specialized systems, such as composting toilets, waste can be reduced even further, potentially down to 30 percent of its original volume.12

The reduction occurs as bacteria and other soil organisms decompose complex organic substances into simpler chemical compounds. This transformation not only diverts organic matter from landfills but also creates a valuable soil conditioner or mulch, supporting sustainable waste recycling practices.341