Difference between revisions of "Composting"

The pre-treatment usually starts with a [[sizing]] activity by chipping the feedstock and subsequently the necessary structural material is mixed in. The purpose of the structural material is to prevent the organic material from caking together. The feedstock mixture is also stripped of metals by means of an electromagnet. In preparation for intensive ripening, a homogeneous airy material is obtained.

Composting occurs through the activity of micro-organisms naturally found in soils. Under natural conditions, earthworms, nematodes and soil insects do most of the initial mechanical breakdown of organic materials into smaller particles. Under controlled conditions, composters break down large particles through grinding or chopping. Once optimal physical conditions are established, soil bacteria, fungi, actinomycetes and protozoa colonize the organic material and initiate the composting process. These mesophilic organisms function best at warm temperatures (10-45°C). As temperatures in the compost pile increase, thermophiles (i.e., micro-organisms that thrive at temperatures above 45°C) take over. In the active "thermophilic" phase, temperatures of 54-65°C are reached which is high enough to kill pathogens and weed seeds and to break down phytotoxic compounds (i.e., organic compounds toxic to plants). After the active composting phase, temperatures gradually decline to around 37°C. The mesophiles recolonize the pile and the compost enters the "curing phase". During curing, organic materials continue to decompose and are converted to biologically stable humic substances (i.e., the mature or finished compost). There is no clearl defined time for curing. Common practices in commercial composting operations range from one to four months.  

The final product is a valuable soil resource. Compost can replace materials like peat and topsoil as seed starters, container mixes, soil amendments, mulches and natural fertilizers.