COMPOSTING PROJECT 2008December 22, 2008
Last time, our group were required to submit a compost project for our Environmental Engineering Course.
Here are some of the points discussed by our professor. It also includes a powerpoint presentation copy of our Compost Project.
Go Clean and Green!!
What is Composting?
• Composting is the controlled decomposition of organic materials, such as leaves, grass, and food scraps, by microorganisms.
• The result of this decomposition process is compost, a crumbly, earthy-smelling, soil-like material.
What to Put in the Mix
• Materials to Include
– Fruit and vegetable
– Egg shells
– Coffee grounds with filters
– Tea bags
– Fireplace ash
– Yard clippings
– Vacuum cleaner lint
– Wool and cotton rags
– Nonrecyclable paper
• Materials to Exclude
– Dairy foods
– Oils (including peanut butter and mayonnaise)
– Pet excrement
– Fish scraps
– Diseased plants
These are some items that can be put in a composting bin. Some food products should not be included because they can attract pests or compromise the quality of the compost. This list is not meant to be all inclusive.
Describe Composting Process
• Compost contains both carbon and nitrogen sources
– browns for carbon (e.g., leaves, straw, woody materials)
– greens for nitrogen (e.g., grass and food scraps).
– Adequate sources of carbon and nitrogen are important for microorganism growth and energy. The ideal ratio is 30 parts brown to 1 part green. Odor and other problems can
occur if the ratio or any of the factors discussed below are not in the correct balance.
• The decomposition of organic materials involves both physical and chemical processes.
– organic materials are broken down by mites, millipedes, beetles, sowbugs, earwigs, earthworms, slugs, and snails. These microorganisms need adequate moisture and oxygen to degrade the organic materials in the most efficient manner.
• Microbes in the pile create considerable heat and essentially “cook” the compost. Temperatures between 90 and 140 oF are common in properly maintained compost piles, but may not reach these levels in backyard compost piles. These high temperatures are necessary for rapid composting as well as for destroying weed seeds, insect larvae, and potentially harmfulbacteria. When the compost is finished, it has a crumbly texture throughout the pile.