The conversion of livestock and poultry manure into organic fertilizer involves scientific formulation, fermentation, and post-processing. Below is a standardized workflow and key technical guidance compiled from multiple technical documents:

I. Core Process Flow

1. Pretreatment Stage

• Raw Material Collection and Solid-Liquid Separation
  • Use solid-liquid separation equipment (e.g., screw or inclined screen separators) to separate solid manure from liquid waste. Solid materials should have a moisture content below 60% for optimal fermentation.
• Formulation Adjustment
  • Carbon-to-Nitrogen Ratio (C/N): Mix livestock manure (e.g., chicken manure, C/N ≈10:1) with carbon-rich auxiliaries (straw, cassava residue, etc.) to achieve a C/N ratio of 25–30:1. Example ratio: chicken manure: cassava residue: straw = 6:2:2.
  • Moisture Control: Maintain mixed material moisture at 50%–65% (hand-test: forms a ball but crumbles when dropped).
  • pH Adjustment: Add lime or plant ash if pH <5.5; incorporate fresh green manure if pH >8.5.
• Inoculation
  • Add 1–2 kg of organic fermentation agent (e.g., lactic acid bacteria, Actinomycetes) per ton of raw material. Activate the agent with brown sugar water before spraying evenly.

2. Primary Fermentation (Aerobic)

• Pile Construction and Turning
  • Form windrows (2 m wide, 1.5 m high). Turn every 2–3 days with a compost turner to aerate and homogenize temperature.
• Temperature Control
  • Maintain high-temperature phase (55–65°C) for ≥10 days to eliminate pathogens, eggs, and weeds. Immediate turning is required if temperature exceeds 70°C.
• Fermentation Duration
  • Typically 8–20 days, depending on raw materials, ambient temperature, and turning frequency. Maturity indicators: pile temperature <40°C, dark brown color, and no odor.

3. Post-Processing Stage

• Crushing and Screening
  • Crush fermented materials and remove impurities (stones, plastics) via sieving. Target particle size: 0.32–1.27 cm.
• Blending
  • Add NPK fertilizers or micronutrients to meet soil requirements, ensuring compliance with NY525-2012 standards (organic matter ≥45%, total nutrients ≥5%).
• Granulation and Drying
  • Granulate using a drum granulator (particle size: 2.5–4.5 mm). Dry to <20% moisture to prevent caking.
• Cooling and Packaging
  • Cool granules to ambient temperature, sieve, and package in opaque bags to avoid sunlight exposure.

II. Key Technical Considerations

1. Sanitization
   • Sustain high-temperature fermentation (55–65°C) for ≥10 days to achieve ≥95% Ascaris egg mortality and E. coli count ≤10⁻¹.
2. Odor Control
   • Mitigate ammonia odors by adding carbon-rich materials (straw, rice husks) or biological deodorants.
3. Maturity Testing
   • Physical Indicators: Stable temperature, dark brown color, odorless.
   • Chemical Indicators: Reduced C/N to 15–20:1, seed germination index (GI) >80%.

III. Equipment and Costs

• Essential Equipment
  • Solid-liquid separator, compost turner, crusher, sieve, granulator, dryer, packager.
• Investment Scale
  • Small-scale plants (5,000 tons/year): ≈68,000–136,000.
  • Large-scale plants (50,000 tons/year): ≈408,000–680,000.

IV. Environmental and Safety Measures

1. Site Requirements
   • Locate fermentation zones away from residential areas. Install impermeable floors and drainage ditches.
2. Safety Protocols
   • Operators must wear respirators and gloves. Avoid direct contact with fermenting materials.
3. Waste Management
   • Collect and recycle leachate into fermentation piles. Prohibit direct discharge.

V. Economic Benefits

• Cost Structure
  • Raw materials (often free or low-cost), fermentation agents (≈2.8/ton),energy(≈4.2/ton), labor.

By following this workflow, livestock manure can be transformed into certified organic fertilizer, balancing resource reuse with environmental sustainability.