How to Process Livestock Waste: Poultry Manure, Pig Manure, and Bedding Material
Introduction
Taiwan's livestock industry is large-scale. Poultry, swine, and cattle farms generate substantial daily volumes of manure, bedding material, and slaughterhouse waste. Without proper management, these materials are not only sources of environmental pollution — they attract insects, generate odors, and create public health risks. Taiwan's environmental regulations have explicit requirements for livestock waste handling; livestock farms and agricultural waste processors alike need to understand the compliant processing approaches.
Granulating and shredding equipment plays an important supporting role in livestock waste processing workflows — whether breaking up solid manure for composting, granulating straw and bedding material for use as composting carbon source or feed supplement, or shredding slaughterhouse waste before entering organic fertilizer production. Each of these stages requires appropriate equipment.
This article covers the characteristics of each livestock waste type, processing workflow, equipment selection, and basic hygiene and environmental compliance requirements.
Characteristics of Each Livestock Waste Type
Poultry manure
Poultry manure is the largest-volume and highest-value livestock waste in Taiwan. It is rich in nitrogen, phosphorus, and potassium — a high-quality organic fertilizer feedstock with stable market demand.
Poultry manure moisture content varies widely depending on rearing method. Cage-raised poultry house manure typically has 50–70% moisture; floor-raised poultry houses where manure mixes with bedding (litter) tend to have somewhat lower moisture — approximately 30–50%.
The main processing challenges for fresh poultry manure are high moisture content and ammonia gas. High moisture makes it difficult to granulate and transport; uric acid in poultry manure decomposes to produce ammonia gas, which is irritating at high concentrations. Ammonia concentration in enclosed spaces requires careful attention.
Pig manure and cow manure
Pig and cow manure typically has higher moisture content than poultry manure. Liquid pig manure from flush-cleaning pig barns may exceed 90% moisture — essentially liquid — requiring solid-liquid separation before the solids can enter a solid-waste processing stream.
Post-separation solid pig manure typically has 60–75% moisture — still elevated and requiring further drying before effective granulation and composting. Cow manure has relatively lower moisture and higher fiber content, making it comparatively easier to handle and one of the most widely used organic fertilizer feedstocks in agriculture.
Pig and cow manure have lower nitrogen content than poultry manure, but high organic matter content — making them excellent composting carbon sources and particularly well suited for blending with high-nitrogen materials (food waste, poultry manure).
Wheat straw, jute bags, and other bedding material waste
Floor-raised poultry houses and some pig barns use rice husks, wood chips, wheat straw, or jute bags as bedding material. End-of-cycle spent bedding is a mixture of feces and bedding material.
These mixed materials are high in solid content and can be granulated directly, but they contain large numbers of pathogens and parasite eggs. High-temperature fermentation or other sterilization treatment is required before processing — spent bedding cannot be granulated directly for agricultural use, to avoid introducing pathogens into soil.
Wheat straw and jute bag fibers have high toughness and tangle granulator blades readily. Cutting pre-treatment before feeding and careful blade type selection for the granulator are essential.
Slaughterhouse waste
Slaughterhouse waste includes bones, feathers, skin scraps, and organ waste. This category is completely different from the previous types — the primary recovery application is producing bone meal, feather meal, blood meal, and similar high-protein feed supplements, or animal-origin organic fertilizers.
Processing slaughterhouse waste requires high-temperature, high-pressure equipment (cooking sterilization) — beyond the scope of standard granulators. This waste is typically handled by government-approved animal by-product processing facilities. General farms and waste processors are not recommended to attempt in-house processing; regulatory restrictions are also more stringent.
Moisture Content Pre-Treatment
Almost all livestock waste faces excessive moisture content — this must be resolved before any downstream processing can begin effectively.
Solid-liquid separation
Liquid manure from flush-cleaning pig and cattle barns is a solid-liquid mixture. Solid-liquid separation is the first required step. The most commonly used separation equipment is a screw press separator — squeezing and separating solid matter from liquid manure. Solids enter the solid-waste processing stream; liquid enters the wastewater treatment system.
Post-separation solids typically have 60–75% moisture — still needing further drying before effective granulation.
Drying treatment
Natural drying (lowest cost): spread solid waste on ventilated surfaces to air dry. Taiwan's rainy season creates instability for outdoor drying; covered drying facilities are needed. Poultry manure generates substantial ammonia during natural drying — the drying facility must have adequate ventilation to prevent ammonia accumulation.
Mechanical drying (rotary drum, belt dryer): fast, weather-independent, but higher capital and energy costs. For large volumes requiring year-round stable processing, mechanical drying is a necessary investment.
High-temperature aerobic fermentation: some operators use thermophilic aerobic composting to simultaneously achieve drying and sterilization. Microbial activity during fermentation raises the pile temperature to 55–70°C, both reducing moisture content and destroying pathogens — a dual-purpose pre-treatment that requires larger fermentation area and turning equipment, but is highly effective.
Granulation Equipment Selection
Livestock waste granulation equipment selection should be based on the waste's moisture content, fiber content, and downstream application.
Processing limits for high-moisture waste
Waste with moisture content above 40% is not suitable for standard granulators. High-moisture waste adheres to blades and screens inside the granulator chamber, causing severe clogging and difficult cleanup. This material must first be dried to below 30% moisture before granulation.
Equipment selection for dried waste
After moisture content is brought to an acceptable range, two main granulator types apply to livestock waste:
Hammer mills suit dried poultry, pig, and cow manure, as well as rice husk and wood chip bedding material. These materials become more brittle after drying; hammer mill impact breaking is effective, delivers high throughput, and has relatively low maintenance cost.
Blade granulators suit mixed bedding waste containing wheat straw, jute bags, and other fibrous materials. However, jute bag and wheat straw fiber toughness is high — material must be cut into short segments before feeding, and blade density must be sufficient. Without these precautions, tangling is severe. For guidance, see: How to Process Textile and Non-Woven Fabric Waste.
Corrosion resistance and hygiene requirements
Livestock waste contains significant organic acids and ammonia — both corrosive to metal equipment components. Granulators processing these materials should use corrosion-resistant materials for the chamber and blades, or at minimum be thoroughly cleaned after each use to prevent corrosive material accumulating on equipment surfaces.
Equipment clean-down design is important. Livestock waste granulators must be easy to disassemble for cleaning — preventing residual waste rotting in the chamber from breeding bacteria, and avoiding cross-contamination between processing batches.
Organic Fertilizer Production and Feed Processing Workflows
Organic fertilizer production workflow
The standard workflow for producing organic fertilizer from livestock waste is: Pre-treatment → Composting fermentation → Turning → Curing → Granulation/pelletizing → Packaging.
Pre-treatment includes solid-liquid separation and moisture adjustment. Composting fermentation is the core step: pre-treated solids and carbon source materials (rice straw, wood chips, agricultural residues) are blended in the appropriate ratio and left for microbial decomposition — either naturally or with added fast-composting enzyme preparations to accelerate breakdown.
The most important management parameters during fermentation are temperature and moisture. Pile temperature must be maintained at 55–65°C for at least three consecutive days to effectively destroy pathogens and weed seeds. Moisture must be maintained at 50–60% — too dry slows microbial activity; too wet causes anaerobic fermentation with strong odors.
Turning every 3–7 days is required for even fermentation — moving outer material to the interior for high-temperature sterilization while replenishing oxygen for continued aerobic decomposition.
After curing, compost is granulated and screened to remove large un-decomposed pieces, producing granulated organic fertilizer for packaging and sale. This granulation stage uses a hammer mill with a 3–5 mm screen to break cured compost into uniform particle size.
Feed processing
Some livestock waste can be converted to feed, but this application has strict regulatory restrictions — not all waste can enter the feed stream. Confirm compliance with applicable feed additive management regulations before proceeding with any feed application. In Taiwan, regulations governing these applications should be verified with the Council of Agriculture.
Wheat straw and agricultural residues granulated for use as roughage supplement for ruminants (cattle, sheep) is a relatively straightforward compliant application. Roughage quality must be confirmed free from mold contamination, and moisture content must be within safe storage limits to prevent molding during storage.
Ammonia Gas Control During Composting
Ammonia is the most actively managed challenge in livestock waste composting operations — particularly with poultry manure, which has very high ammonia volatilization rates.
Beyond its irritating odor, ammonia is demonstrably harmful to the respiratory system at high concentrations. Taiwan's occupational safety and health regulations set workplace ammonia concentration limits (short-term exposure limit 35 ppm; time-weighted average 25 ppm). Livestock waste processing facilities must ensure ventilation design keeps ammonia concentrations below these standards.
Practical methods to reduce ammonia volatilization: adding phosphate materials to the compost pile to fix ammonium-nitrogen; covering pile surfaces to reduce volatilization area; ensuring sufficient ventilation to quickly dilute and exhaust volatilized ammonia.
Operators performing pile turning and granulation should wear activated-carbon masks rather than standard dust masks — the activated-carbon filter layer effectively adsorbs ammonia for more complete operator protection.
Conclusion
The core challenges of livestock waste processing are moisture content management, pathogen sterilization, and ammonia control. Solving these three problems is the prerequisite for the downstream granulation and application process to run smoothly.
Granulating equipment plays a supporting — not leading — role in the livestock waste processing workflow. Before planning the complete processing configuration, confirm your primary waste source, waste volume, and target application outlet (organic fertilizer, feed, biomass fuel), then determine the equipment configuration for the entire process.
For Taiwan's livestock waste regulatory requirements, confirm compliance obligations with your local environmental bureau and the Council of Agriculture before investing in equipment — to avoid discovering that additional permits or environmental facility upgrades are required after installation. For agricultural residue processing guidance, see: How to Process Agricultural Residues. For composting carbon source selection, evaluate using agricultural residues in combination with livestock waste.