Hoggery Wastewater Treatment: Characteristics And The Anaerobic-Aerobic Train
Hoggery wastewater is the manure-in-water stream from pig farms - high in ammonia, sulfide, suspended solids, and organic load. A robust train treats it in two stages: an anaerobic reactor (UASB or USR) removes the bulk of the COD and recovers biogas, then an aerobic stage (typically AOAO - anoxic/oxic) polishes residual COD, nitrogen, and phosphorus to meet discharge or reuse limits. The design is set by concentration and solids, not by a single catalogue unit.
What Is In Hoggery Wastewater
Pig farms use hydraulic flushing or 'water-submerged' manure collection, which dilutes the manure into a high-volume, high-strength stream. The result is a mix of dissolved organics, fine solids, ammonia from urea, and sulfide from anaerobic pockets in the pit. Because the ammonia and sulfide are corrosive to ordinary steel and inhibitory to biology if unchecked, the materials and the first reactor choice both matter. A dairy or poultry stream differs in solids and nitrogen profile, so pig wastewater gets its own train.
| Parameter | Typical hoggery range | Why it matters |
| COD | 8,000-20,000 mg/L | Sets anaerobic reactor volume |
| BOD5 | 5,000-12,000 mg/L | Biodegradable fraction |
| Ammonia-N | 800-2,000 mg/L | Inhibits methanogens if high |
| Total solids | 1-8% (water-submerged) | Decides CSTR/USR vs UASB |
| Sulfide | Variable, from pits | Corrosion + odor |
The Anaerobic Stage - UASB Or USR
The anaerobic step does the heavy lifting on COD and produces biogas. For raw, high-solids pig manure, a CSTR (continuous stirred tank) or USR (upflow solids reactor) tolerates the suspended load and buffers shocks. For clarified liquid after solid-liquid separation, a UASB (upflow anaerobic sludge blanket) or IC reactor achieves a high organic loading rate on a smaller footprint. USR, in particular, is a common choice for pig farms because it handles the solids that would otherwise blind a UASB's granular bed.
| Reactor | Best feed | Notes |
| CSTR | High suspended solids | Stable, well-mixed |
| USR | Manure with solids | Handles high SS, simple |
| UASB / IC | Clarified low-SS liquid | High OLR; needs pre-separation |
The Aerobic Polish - AOAO
Anaerobic effluent still carries ammonia, residual COD, and phosphorus, so an aerobic polish follows. AOAO (anoxic-oxic) gives denitrification and nitrification in one train and is widely applied to pig wastewater; it strips the ammonia that anaerobic biology cannot. The final effluent then meets the limits a discharge permit sets - the design target, not a fixed number.
| Stage | Unit | Role |
| 1 | UASB / USR | Bulk COD + biogas |
| 2 | AOAO | N, P, residual COD |
| 3 | Sludge + disinfection | Solids + pathogens |
Project Reference - Beijing 5S Pig Farm
A pig farm wastewater project in Beijing applied a UASB + AOAO train (capacity 580 m3/day, installed 2020). Published water-quality data below is shown as a real before/after reference; other project details beyond location, process, and these values are not released, so no further figures are asserted.
| Pollutant | Influent | Effluent | Removal |
| COD Cr | >= 10,000 mg/L | <= 200 mg/L | ~98% |
| BOD5 | >= 8,000 mg/L | <= 100 mg/L | ~99% |
| Ammonia-N | >= 1,000 mg/L | <= 80 mg/L | ~92% |
| Total P | >= 200 mg/L | <= 8 mg/L | ~96% |
| SS | >= 10,000 mg/L | <= 100 mg/L | ~99% |
| Fecal coliforms | >= 5.6e6 CFU/100ml | <= 4.0e3 CFU/100ml | ~99.9% |
About Company
Shijiazhuang Zhengzhong Technology Co., Ltd (Center Enamel) is a comprehensive high-tech enterprise specializing in wastewater engineering, process section contracting, and equipment manufacturing. The company delivers biogas and wastewater projects through three main lines - EPC (turnkey) contracting, equipment supply, and process packages - covering livestock and municipal wastewater, biomass energy, industrial wastewater, and food waste. Its reactor portfolio spans CSTR, USR, UBF, UASB, IC, and EGSB, backed by in-house Glass-Fused-to-Steel tank manufacturing (enamel firing at 820-930 C) and certifications including ISO 9001, NSF/ANSI 61, and CE-EN 1090. With 35+ years of operation, a 150,000 m2 manufacturing base, and projects in 100+ countries, Center Enamel provides the single-responsibility engineering behind livestock wastewater projects such as the Beijing 5S pig farm UASB + AOAO reference, where a documented influent/effluent table shows the anaerobic-aerobic train at work - a scoped, evidenced application rather than a generic claim.
Conclusion
Hoggery wastewater treatment is the species-specific pairing of an anaerobic reactor that tolerates manure solids with an aerobic polish that removes nitrogen and phosphorus - sized from concentration and volume, not from a catalogue.
Frequently Asked Questions
Q1: What makes hoggery wastewater hard to treat? A1: High ammonia, sulfide, suspended solids and COD from manure-in-water need an anaerobic stage that tolerates solids, then aerobic polishing.
Q2: Which anaerobic reactor fits pig wastewater? A2: CSTR or USR for high suspended solids; UASB/IC only after solid-liquid separation.
Q3: What is a typical UASB plus AOAO train? A3: UASB removes bulk COD and makes biogas; AOAO polishes COD, nitrogen and phosphorus.
Q4: What COD removal can a pig plant achieve? A4: The Beijing 5S reference shows COD >=10,000 to <=200 mg/L and BOD5 >=8,000 to <=100 mg/L.
Q5: Why treat pig wastewater instead of storing it? A5: Odour, pathogen and nutrient-runoff risk; treatment recovers biogas and a fertilizer-grade digestate.
Q6: How long is anaerobic retention for pig manure? A6: CSTR/USR typically 15-30 days mesophilic; shorter risks incomplete digestion.
Q7: Does pig wastewater produce biogas? A7: Yes - the high COD manure yields biogas recovered on-farm for heat or power.
Q8: What permits apply to pig farm wastewater? A8: Discharge limits on COD, ammonia, TP, SS and faecal coliforms, as shown in the Beijing 5S table.
Suggested CTA
Send your pig farm's daily volume, concentration, and discharge limit to an engineer, or request a scoped hoggery wastewater treatment outline.