waste management - composting

What composting is

Biological decomposition of organic waste under controlled aerobic conditions

Why composting is used

Reduces odors, stabilizes nutrients, lowers volume, and produces usable soil amendments

Moisture requirement

Initial moisture should be 45–55%

Problems with excess moisture

Causes low oxygen, odors, and low temperatures

C:N ratio requirement

Initial C:N ratio = 25–40:1

Low C:N materials

Manure (C:N 5–15)

High C:N materials

Straw, shavings (C:N 80–200)

Oxygen requirement

Needs 5–15% oxygen for aerobic microbes

Temperature phases

Psychrophilic → Mesophilic → Thermophilic → Maturation

Thermophilic temperature

Above 105°F; kills pathogens and speeds decomposition

pH requirement

Optimal pH 6.0–7.5

Benefits of composting

Reduces odors, pathogens, volume, and transport cost; creates marketable product

Windrow composting

Long piles; can be static or turned for aeration

PAWS system

Passively aerated windrow using perforated pipes to pull air in

Aerated static pile

Forced air through pipes; no turning required

In‑vessel composting

Enclosed system (drum, silo, agitated bed); fastest and most controlled

Why mortality composting is needed

Carcasses contain high organic matter, pathogens, odors, and nutrients

Mortality composting advantages

Low cost, biosecure, environmentally friendly, uses farm resources

Basic mortality compost mix

1.5–2 parts litter : 1 part birds : 1 part straw + water

Mortality composting moisture

Target ~50% moisture

Mortality composting oxygen

Requires >5% oxygen

Mortality composting C:N

C:N ratio 15–35:1

Layering procedure

Litter base → straw → carcasses → water → cover with litter

Turning schedule

Turn when temperature drops (usually after 10+ days)

Decomposition time

95–100% tissue breakdown in ~4 weeks

Biosecurity requirement

Must be fenced/covered; workers need PPE during disease events

Final compost product

Stable, low‑odor material usable as soil amendment or bedding

Environmental benefits

Reduces runoff risk, stabilizes nutrients, lowers pathogen load