Composting is an age old practice of waste management whereby the organic components of the waste streams are biologically decomposed under controlled conditions to a stabilized state that can be safely handled, stored or applied to land as a soil amendment.

Composting can occur in the presence of oxygen referred to as aerobic composting, or in the absence of oxygen referred to as anaerobic composting. Most modern compost systems are aerobic for important reasons.

Aerobic composting is:

There are three methods of aerobic composting with the windrow method being the most cost effective.

Methods of Aerobic Composting

Raw Materials

The raw materials for composting can be split into two categories: Carbon sources and Nitrogen sources.

Characteristics of Nitrogen Sources:   Examples of Nitrogen Sources:
Wet   Livestock manure
Decompose quickly   Food waste
High in nitrogen   Grass
High bulk density    
Not very rigid    
Characteristics of Carbon Sources:   Examples of Carbon Sources:
Dryer   Corn Stalks
Decompose slowly   Leaves
Low in nitrogen   Sawdust
Low bulk density   Wood chips
Somewhat rigid    

Fresh Compost: Has undergone partial decomposition, but it is not stabilized and continues to breakdown.

Mature Compost: Generally suitable as an organic soil conditioner, but is only partially stabilized and may temporarily arrest plant growth if it comes in direct contact with the roots.

Cured Compost: Highly stabilized product, excellent organic soil conditioner

Class A: Includes cured compost, suitable for lawn and garden application, referred to as designer compost

Class B: Includes fresh and mature compost, used as an agronomic soil amendment

Analysis of Raw Materials

Wood chips 83.08 35.84 1.27
Grass 58.39 43.99 3.79
Leaves 77.75 48.02 1.37
Solid Manure 49.10 25.75 1.38
Liquid Manure     .5072

Analysis of Mature Compost

pH %DM Ash %N %C C:N
7.6 64.43 67.31 1.75 18.16 11:17

Solid Livestock Waste
1.59 lbs. manure: 1 lb. landscape waste
652.0 lbs manure: 1 cu. yd. landscape waste
1.96 tons of raw material to make 1 ton compost

Swine Liquor-Grass
.20 lbs. liquid manure: 1 lb grass
135.59 lbs. liquid manure: 1 cu. yd. grass
1.82 tons raw material to make 1 ton of compost

Compost Process
No. of turns - 11
Days between turns - 5.2
Days from first to last turn - 53
Days to compost - 75

Swine Liquor - Wood Chips
3.19 lbs. liquid manure: 1 lb. wood chips
1592.59 lbs. liquid manure: 1 cu. yd. wood chips
5.78 tons of raw material to make 1 ton of compost

Compost Process
No. of turns - 16
Days between turns - 2.2
Days from first to last turn - 33
Days to compost - 151

Key Factors to Composting

Moisture content

Carbon to Nitrogen Ratio


Windrows should be turned to accomplish this.

Windrow Turning Frequency:
First 3 - 5 Days: Turn Daily
Next 3 - 4 Weeks: Turn 2 - 3 Times/Week
Week 5 to End: Turn Once/Week

The Illinois EPA, Bureau of Land and Bureau of Water regulates composting and in some instances permits are required.

Compost Siting Regulations

Permits are not required if:

Permits are required:

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University of Illinois at Urbana Champaign College of Agricultural Consumer & Environmental Sciences University of Illinois Extension