What is compost (more complete definition)

Composting is the controlled aerobic (oxygen-using) biological decomposition of moist organic (biologically derived carbon-containing) solid matter to produce a soil conditioner. Composting works through the use of microorganisms which break down organic matter, mainly a wide range of bacteria and fungi . Also highly active within the compost system are many invertebrates , such as red worms, which transport oxygen and moisture throughout the compost mass while they assist the physical and chemical breakdown. Bulking material (typically, shredded bark mulch) is added to help maintain a porous texture that promotes aeration and good moisture content. Pathogens are killed not only by the heat within the composter but also by predatory organisms and the long retention time in the system.

What makes composting manure unique?

In a composting toilet, the objective is to transform potentially harmful residuals -- mostly human excrement -- into a stable, oxidized form. The primary microorganisms responsible for composting are bacteria, actinomycetes and fungi. However, algae, mixomycetes (slime molds), viruses, lichens and mycoplasmas are other organisms present in the compost process. Soil animals, such as protozoa, amoeba, nematodes, earthworms and arthropods, also perform major roles by degrading surface litter, consuming bacteria and assisting in aeration.

Traditionally dog feces is not considered appropriate for composting. Most city agencies, as well as the EPA, discourage placing feces along with food scraps and yard waste in the compost bin. The largest reason is pathogens, if pet medications or round worms can be passed to humans it can cause a serious health risk. For this reason composeted dog manure should not be used in vegetable gardens.

Unlike other animal manures, dog feces is high in nitrogen so it impacts the carbon to nitrogen ratio, which significantly impacts the decomposition process. Bacteria and funcgi oxidize carbon as an energy source and ingest nitrogen for protein systhesis. To offset the high nitrogen level, you must add a carbon based bulking agent (such as sawdust).