Alternative Waste Management: Composting

1. Organic Sustainable Biologically- Intensive BIOAg Alternative Waste Management: Composting General and Special Uses Dr. Lynne Carpenter-Boggs BIOAg Coordinator WSU CSANR

2. BIOAg=Organic and/or bio-intensive, if it’s sustainable. • Organic agriculture: A legally defined and regulated practice that focuses on use of natural materials & non-use of synthetic pesticides, fertilizers, etc. • Biologically Intensive: using • renewable biological materials & • processes. • Sustainable: Producing high quantity and quality food & fiber with long-term economic, environmental, & social viability. Organic Biologically- Intensive Sustainable BIOAg

3. Composting Advantages • Reduces odors • Volume reduction • Nutrient concentration • May result in a marketable product • Potential income by incorporating other waste streams • Reduced pathogens • Relatively simple Disadvantages • Requires two handling systems – liquid and solid • Does NOT address excess nutrient problem • May not have an available market for product

4. What is composting? • Decomposition en masse • The transformation process is similar to that which occurs in every topsoil • Transformation of raw materials • biologically • chemically • physically • Bacterial and fungal activity • thermophilic = heat-loving organisms • Microaerobic = not fully aerobic, not anaerobic

5. Composting is a biological process wherein organic raw materials or “feedstocks” are transformed by organism activities into a stabilized soil-like material called compost. Heat CO2 Raw materials • Organic matter • Oxygen • Water • Microbes Finished compost with humic matter

6. Compost Temperature • Tremendous microbial activity produces heat. Thermophiles • At ~130 F, most plant and animal pathogens and weed seeds die. 130 F  active phase curing phase Temperature Time

7. Good compost builds rich topsoil • Complex humic acids (humus) form. • Composted material is darker, particles are smaller and softer, texture is fine like good topsoil. • Good compost is often unrecognizably different from its feedstocks. • No unpleasant odor, no undecomposed material, and stable in long-term storage. • Approx. ½ of C, volume, and mass have been lost but most nutrients were retained.

8. Create a Composting Environment Factor OK range Optimum C:N 20:1 – 50:1 25-30:1 Moisture 40 – 65% 50 – 60% Oxygen >5% >>5% pH 5.5 – 9.0 6.5 – 8 Particle size 1/8 – ½” varies

9. Material C:N ratio Wood 400:1 Wide or high C:N Narrow or low C:N Animal carcass 5:1 Energy materials Soil humus 10:1 Young grasses 20 - 40:1 Balanced materials Manure 20 - 50:1 Wheat straw 80:1 Bulking materials Tree leaves 60 - 100:1

10. Passive composting pile • Temperature will rise, stabilize, slowly drop. • Minimal management • Inconsistent results.

11. Aerated Windrow Composting Blower Perforated pipe NRCS National Engineering Handbook Part 637 -Chapter 2 Composting

12. Compost Temperature –Passive or static system 130 F  active phase curing phase Temperature Time

13. Turned composting • Heavy equipment used to mix compost every 1 - 14 days

14. Compost Temperature – Turned System • When compost no longer reheats after turning, curing begins. • Decomposition continues to slow, but never really ends. 130 F  turn turn turn Temperature active curing Time

15. Composting Bins

16. 4-bin composter - Iowa

17. Compost quality determines its best use • 3 primary uses for compost: • potting soil (best quality required) • soil amendment, turf topdressing • mulch (esp. for compost with C:N>25) • The closer the plant contact (in space and time), the greater the quality and maturity must be. Lower quality composts may be used as mulch, or less mature compost may be incorporated in soil several months prior to planting.

18. Special-use compost: livestock bedding • Starting and ending materials have higher C:N • Some “high energy” feedstock necessary for producing high temperature • Larger particle sizes ok • Final product drier (25-40% moisture) • Compost as bedding may reduce mastitis

19. Specialized composting: livestock carcass disposal • Not rocket science, but must be done right • Some high carbon feedstock necessary for collecting moisture, odor, balancing the high-N carcass • Composting saves money and nutrients

20. Mortality is a Waste Management Issue • A carcass is a concentrated source of organic matter • it is a source of odors • it is a source of undesirable critters • it is a potential source of pathogens • it is a source of nutrients • Thus, the mortality problems are similar to manure problems

21. Planning for the Impossible... • Natural disasters can and do happen • Flooding (IA, 1993 & NC, 2000) • Heat Waves (CA, 2005) • Snow (Blizzard of 1993) • millions of broilers and chicks lost to building collapse and loss of power for heating • Whole herds may be destroyed

22. Responding to tragedy

23. Passive Piles or Windrows Place the carcass on >24” high-carbon base to absorb moisture & allow airflow

24. Cover the Carcass, Build the Pile Minimum 24” co-composting material around the carcass to help decompose, discourage critters, and allow airflow

25. WAIT -- Composting takes time • An active pile stays hot. This pile was 135-152 F through December. • With carcasses, wait ~2-6 months before disturbing the pile

26. Typically only large bones are left identifiable after 2-6 months. Re-compost these quickly.

27. Allow 1-2 more composting periods • Temperature will rise again, but not as hot.

28. Special-use compost: organic agriculture • Moderate-to-high quality compost • Must follow special NOP regs: • Feedstock mix C:N must be 15 – 60:1 • Temperature must reach 131 F at least 3 days • Turn or ensure that all parts of pile reach temp • Test for E. coli, Salmonella • Use a turned or aerated system, not passive • No biosolids, no prohibited materials used • If requirements not met, use as if it’s manure

29. Composting – It’s hot!