Pig Manure Processing: Complete Organic Fertilizer Production Guide

Raw swine manure (pig dung and slurry) is rich in organic nitrogen, phosphorus, potassium, and trace minerals. However, unprocessed pig manure presents major operational and environmental risks: it carries high moisture levels, heavy metal residues (such as zinc and copper), foul odors, plant-pathogens, and weed seeds. Direct field application leads to root burn, soil compaction, and environmental compliance violations.

Converting raw pig waste into stabilized bio-organic fertilizer granules turns an environmental liability into a valuable commercial product.

This guide details the physical pre-treatment, C/N ratio balancing, aerobic composting, fine grinding, and pelletizing equipment needed to process pig manure into commercial organic fertilizer.

1. Raw Material Baseline & Dewatering Pre-Treatment

Fresh pig waste collected from flush-flushing or scrapers typically features 80% to 90% moisture content. Dewatering is mandatory before aerobic composting can begin.

[Raw Pig Slurry / Manure] ──► [Submerged Non-Clogging Pump]
                                           │
                                           ▼
[Liquid Effluent to Lagoon] ◄── [Screw Extrusion Dewatering Machine]
                                           │
                                           ▼
                       [Dewatered Manure Cake (50%-60% Moisture)]

• Screw Extrusion Solid-Liquid Separator: A non-clogging submerged slurry pump feeds raw pig waste into an inclined stainless steel wedge-wire screen. High-torque auger screws squeeze excess water out of the solids.
• Moisture Target: Reduces raw manure moisture down to 50%–60%, establishing the optimal baseline for aerobic microbial digestion.
• Liquid Phase Handling: Separated liquid effluent routes to anaerobic digesters (biogas generation) or liquid storage lagoons for controlled pasture fertigation.

2. C:N Balancing & Aerobic Composting

Raw pig manure has a narrow Carbon-to-Nitrogen (C:N) ratio (roughly 6:1 to 12:1), which causes nitrogen loss via ammonia gas if unadjusted.

Carbon-to-Nitrogen (C:N) Adjustment
To achieve proper microbial composting, high-carbon bulking materials must be blended into the dewatered pig manure to reach a target C:N ratio of 25:1 to 30:1:

• Recommended Bulking Agents: Sawdust, rice husks, wheat straw powder, or spent mushroom substrate.
• Standard Blending Proportions: ~80% dewatered pig manure to 20% dry carbon materials by mass.

Fermentation Equipment Options

Thermophilic Phase (55℃~65℃): Compost turners or vertical fermenters supply continuous oxygen to maintain high microbial temperatures for at least 5–7 days, killing E. coli, Salmonella, and weed seeds.

3. Core 3-Step Simplified Fertilizer Line Setup

For small-to-medium scale plants, a streamlined Composting $\rightarrow$ Mixing $\rightarrow$ Granulating setup minimizes machinery CAPEX while producing uniform commercial granules.

[Aged Compost (30%-40% Moisture)] ──► [Semi-Wet Material Crusher]
                                                │
                                                ▼
  [Functional Microbes / Minerals] ──► [Horizontal Double Shaft Mixer]
                                                │
                                                ▼
   [Commercial Organic Pellets] ◄── [Organic Granulator / Roller Extruder]

Step 1: Fine Pulverization (Semi-Wet Crusher)

Equipment: Semi-Wet Material Crusher.

Function: Fermented pig manure cakes contain moisture (30%–40%) that clogs standard hammer mills. The screenless, twin-rotor design shatters sticky compost lumps into a uniform 40–80 mesh fine powder without mesh blinding.

Step 2: Homogeneous Blending (Double Shaft Mixer)

Equipment: Horizontal Double Shaft Mixer.

Function: Blends pulverized pig manure powder with humic acid, potassium mineral powders, or heat-resistant bio-inoculants (Bacillus subtilis) in 2–3 minutes per batch.

Step 3: High-Yield Granulation (Pelletizing)

Option A (Wet Granulation): New-Type Organic Fertilizer Granulator. High-speed internal rotating agitation converts damp organic compost into dense 2–5mm spherical granules without requiring chemical binders.

Option B (Dry Granulation): Double Roller Extrusion Granulator. If compost moisture is low (<10%), dry compaction presses powder into solid sheets before breaking them into dense pellets—completely eliminating rotary drying fuel costs.

4. Screening, Thermal Handling, & Automated Packaging

For commercial distribution, the wet granules undergo finishing processing to ensure long shelf-life and dust-free handling:

Direct-Fired Rotary Dryer & Cooler: Lower granule core moisture below 12% and cool pellets to ambient room temperature.

Rotary Drum Screening Machine: Isolates target 2–5mm granules. Oversized pellets are crushed via a chain crusher, while undersized dust returns to the mixer via recycle conveyors.

Automated Quantitative Packaging Scale: Weighs and seals finished granules into 25kg, 50kg, or ton bags for commercial transport.

Operational Tips for Pig Manure Processing

• Monitor Heavy Metal Concentrations: Pig feeds often contain elevated copper and zinc levels. Regularly test composted manure batches to ensure heavy metals fall within regional commercial organic fertilizer standards.
• Manage Odor Outflows: Use covered composting sheds with bio-filter exhaust hoods or enclosed vertical fermentation tanks if your facility operates close to residential zones.
• Reduce Energy OPEX: Use mechanical dewatering upfront to reduce dryer fuel demands down the line.

Request Your Pig Manure Fertilizer Plant Layout

Building a high-efficiency pig manure processing line requires matching raw slurry volumes with the correct dewatering capacities, compost turners, and granulators. Contact our senior technical engineering team today to receive custom plant blueprints, machine specs, and factory-direct equipment quotations!