Manure management is a critical aspect of environmental protection in the livestock industry, requiring scientific solutions tailored to farm scale, surrounding environment, and resource availability. Below is a systematic overview of treatment methods, technological models, policy standards, and practical case studies.

I. Mainstream Treatment Methods and Technologies

1. Physical Treatment: Solid-Liquid Separation and Pretreatment

• Dry-Wet Separation: Using equipment like inclined-plate separators or screw presses to divide manure into solid and liquid fractions. Solids are used for composting or bedding, while liquids enter further treatment systems.
• Sedimentation Tanks: Primary settling of large particles in liquid manure to reduce downstream processing load.

2. Biological Treatment: Core of Resource Utilization

• Composting:
  • Aerobic Composting: Microbial decomposition under aerobic conditions generates high temperatures (60-70°C) to eliminate pathogens. Suitable for poultry and cattle manure (e.g., Anhui Tianchang goat farm uses windrow composting with a 30-60 day cycle).
  • Anaerobic Digestion: Organic matter breakdown in sealed biogas digesters produces methane-rich biogas (60-70% methane), digestate, and effluent. Requires temperature control (mesophilic 35°C or thermophilic 55°C), with winter insulation needed in cold regions.
• Off-Site Fermentation Beds: Liquid manure sprayed onto bedding (sawdust, straw) with periodic aeration for simultaneous solid-liquid fermentation, ideal for water-saving farms.

3. Ecological Treatment: Integrated Farming Models

• Oxidation Ponds: Liquid manure stored in open or covered ponds for fermentation via algae and microbial activity, followed by land application. Requires seepage control and rainwater diversion.
• Constructed Wetlands: Plant uptake and microbial degradation purify effluent, suitable for land-rich areas.

4. Chemical/Physical Auxiliary Methods

• Disinfection: Using bleaching powder or quicklime for pathogen control in contaminated areas (caution against chemical residues).
• Membrane Technology: Semi-permeable membranes in aerobic fermentation systems enable efficient oxygen/water control, effective in cold climates.

II. Technological Models and Application Scenarios

1. Integrated Farming-Livestock Model

• Full Manure Recycling: For farms with adjacent farmland. Example: Hubei Zhongxiang pig farm ferments manure in oxidation ponds before irrigation, using solid-liquid separators and pumps.
• Compost Utilization: Solid manure transformed into organic fertilizer via high-temperature composting (e.g., Anhui Tianchang goat farm processes 6,000 tons/year).

2. Clean Recycling Model

• Manure Bedding: Dairy farms use fermented manure instead of sand for cow comfort (e.g., Hebei Huanghua dairy farm with super-heated fermentation).
• Substrate Production: Combined with mushroom residue/straw to create cultivation media for horticulture.

3. Energy Recovery Model

• Biogas Plants: Large-scale farms generate electricity or biomethane from biogas, with digestate as fertilizer (e.g., Guangxi Tiandong dairy farm processes 200,000 tons/year for 8 million m³ biogas).

4. Discharge Compliance Model

• Advanced Treatment: Combination of "pretreatment + anaerobic + aerobic + membrane filtration" to meet discharge standards. Suitable for farms without farmland access, though costly.

Conclusion

Manure management should prioritize resource recycling, selecting models based on technical feasibility, economics, and environmental compliance. Small-medium farms may favor composting/off-site beds, while large operations explore biogas or centralized processing. Continuous policy adaptation and technological innovation are essential for sustainable livestock farming.