Chapter 3: ESSENTIAL COMPONENTS OF COMPOSTING

1. Chapter 3:ESSENTIAL COMPONENTS OF COMPOSTING Kentucky Department of Environmental Protection Division of Compliance Assistance 300 Fair Oaks Lane • Frankfort, KY 40601 Phone: 502.564.0323 • 800.926.8111 • Fax: 502.564.9720 Email: envhelp@ky.gov • Website: dca.ky.gov

2. Understand the types and components of solid and special waste. Comprehend the biological processes associated with composting. List the essential components needed for controlling decomposition. Chapter 3 Objectives

3. Composting is a biological processinfluenced by the basic conditions that affect all living beings. By Kentucky statute, composting involves the biological decomposition of organic materials in controlled aerobic conditions.

4. Controlled distinguishes composting from the natural rotting, putrefaction, or other decomposition that takes place in an open, unmanaged condition. • Aerobic means that composting must occur in an oxygenated environment. • Biological distinguishes the process from chemical and physical treatment. Key Terms

5. Decomposition is used because the composting process is rarely carried to complete stabilization. • Organic describes materials of a carbon source that are capable of being broken down biologically. Key Terms

6. Composting is a biological process carried out primarily by microorganisms. • The microbes are affected by the same environmental factors as other organisms: • - Oxygen - pH - Water - Particle Size - Temperature Composting Process

7. Common- They naturally occur in nature and on waste material. • Fast growing - Microbe populations can double several times a hour. • Usuallybacteria (mostly) and fungi Microorganisms are:

8. Bacteria: • Mainly responsible for decomposting materials. • Primarily decompose “greens.” • Appear in the later stages of composting. • Responsible for breaking down tougher materials. Bacteria and Fungi Fungi:

9. The doubling of microbe populations several times per hour results in accelerated organic matter decomposition. • This decomposition results in the production of heat, the most obvious indicator of compositing. Composting Process

10. Optimal Composting Conditions

11. Aerobically (with oxygen) • High temperatures • Absence of foul odors • More rapid decomposition • Anaerobically (without oxygen) • Low temperatures • Odorous • Slow decomposition Aeration

12. Oxygen is added to composting materials either by passive or active means. How to Get Oxygen Passively: • Pile size remains small (5”-10”) • Particle size is medium to large • Add bulking agent to create larger pores to allow passive movement of oxygen.

13. Chimney Effect How to Get Oxygen Passively HOT Cool Air Cool Air

14. How to Get Oxygen Actively TURNING MIXING

15. Turning • First turning should occur when temperature climbs steadily and reaches 140-150 F. • If temperature levels off at 100-120 F, the pile should be turned immediately to avoid going anaerobic.

16. Turning With each turning: • The peak temperature reached may be slightly less than the previous one. • Particle size tends to decrease, so oxygen must be carefully monitored. • When heat increases (>20˚F above ambient) do not occur after turning, compost is stable and ready to cure.

17. Anaerobic Zones • There may be small anerobic zones within the pile that release smells during turning. • When large portions of the compost goes anaerobic, it is difficult to get them back to an aerobic state. • This usually indicates bad management.

18. Temperature • Composting organisms respond to temperature just like other organisms. Rates slow down when temperatures get too cold or too hot. • Optimum temperature for composting should be between 90-140˚F.

19. Temperature • Size and porosity contribute to heat loss. • Turning and mixing will also contribute to heat loss.

20. Temperature • Pile temperatures change over time as materials are decomposed.

21. Moisture • Ideal moisture of compost should equal that of a damp sponge. • If the moisture is too low: • Microbial population expansion slows • Material will not compost, sometimes molds • If the moisture is too high: • Restricts oxygen leading to anaerobic conditions • Temperature loss

22. Moisture • Porous Material • Has greater air movement • Dries faster • Mixes well within wet heavy material

23. Moisture • Fine Material: • Reduces the rate of drying • Retains moisture for longer periods of time

24. Carbon : Nitrogen Ratio • Two most important nutrients for microbes to grow and reproduce • Beginning ratio should be in range of 25-40:1

25. Carbon : Nitrogen Ratio • Carbon the building block of carbohydrates is high in cellulose materials • Paper, wood, leaves • Provides energy to the microbes

26. Carbon : Nitrogen Ratio • Nitrogen is the building block of proteins and found mostly in “green”materials • Grass clippings, sewage sludge, animal manures • Provides proteins to microbes for cell growth and expansion of populations

27. High nitrogen materials

28. High carbon materials

29. Carbon:Nitrogen Ratio • What’s your recipe? • Blend high C:N materials with low C:N materials to get into the 30:1 range. • Sawdust + grass clippings or manure • High N materials may need more frequent turning for aeration and temp control • On-line compost calculators are available

31. Small Particle Size • More surface area available for microbes to work • Nutrients and energy are more available to the microbes • Increases rate of decomposition in general • Require more frequent turning for aeration due to higher density

32. Large Particle Size • Used as a bulking agent to improve passive area flow • Slow composting process (less surface area) • Decrease uniform product unless screened or extra time is allowed • Marketing problem

33. Particle Size

34. pH • Compost process most efficient when the pH is 6-8 • Useful in diagnosing and correcting problems • Low pH slows composting process • High pH (>8) can cause release of odorous ammonia • Neutral pH best for most uses of compost

35. Composting is a process that requires continuous monitoring and management Be ready to change things if your compost is not developing properly!

36. Understand the types and components of solid and special waste. Comprehend the biological processes associated with composting. List the essential components needed for controlling decomposition. Chapter 3 Objectives