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How Biological Treatment Works

Biological treatment leverages naturally occurring bacteria to metabolize organic compounds in brewery wastewater. The process converts soluble and colloidal organics into biomass, carbon dioxide, water, and in anaerobic systems - valuable biogas.

Hydrolysis

Complex organics (proteins, carbs, fats) are broken down into simpler compounds by extracellular enzymes

Acidogenesis

Simpler compounds are converted to volatile fatty acids (VFAs) by acid-forming bacteria

Acetogenesis

VFAs are converted to acetic acid, hydrogen, and carbon dioxide

Methanogenesis

Methane-forming archaea produce biogas (60-70% CH4, 30-40% CO2)

Biological Treatment Configurations

Choose the optimal biological system based on your brewery's BOD loading, space constraints, and energy recovery goals.

SBR - Sequencing Batch Reactor

Flexible batch operation

Single-tank system that operates in timed sequences, providing excellent treatment with simple operation. Handles variable flows well - perfect for batch brewery operations.

  • BOD Removal 90-97%
  • Effluent BOD < 30 mg/L
  • Footprint Compact
  • Sludge Production Medium
  • Energy Use 0.3-0.6 kWh/m³
  • Best For Variable flows, BOD < 5,000 mg/L
Learn About SBR

UASB - Upflow Anaerobic Sludge Blanket

Energy recovery

Anaerobic system that converts organics to biogas while treating high-strength wastewater. Produces 80-90% less sludge than aerobic systems with valuable biogas for boiler fuel.

  • BOD Removal 70-90%
  • Effluent BOD 200-500 mg/L
  • Footprint Moderate
  • Sludge Production Very low
  • Biogas Yield 0.35 m³/kg COD
  • Best For BOD > 5,000 mg/L
Learn About UASB

IC Reactor - Internal Circulation

High-rate anaerobic

Advanced high-rate anaerobic reactor with internal circulation for superior mixing and biomass retention. Handles very high organic loads with minimal footprint.

  • BOD Removal 80-95%
  • Effluent BOD 100-300 mg/L
  • Footprint Very compact
  • Loading Rate 15-30 kg COD/m³/d
  • Biogas Yield 0.35 m³/kg COD
  • Best For BOD > 10,000 mg/L
Learn About IC

When to Use Biological Treatment

Biological treatment is the preferred choice for most brewery wastewater applications. Here's when it makes the most sense:

What is your typical BOD concentration?

< 3,000 mg/L: Aerobic MBR or SBR is ideal. Lower capital cost, excellent effluent quality.

3,000 - 8,000 mg/L: MBR with specialised membranes, or consider anaerobic + aerobic combination.

8,000 - 20,000 mg/L: UASB or IC reactor for biogas recovery, followed by aerobic polishing.

> 20,000 mg/L: High-rate anaerobic (IC) essential for energy recovery and efficient treatment.

How much space do you have available?

Limited space: MBR provides smallest footprint. IC reactor for high-strength streams.

Moderate space: SBR or conventional activated sludge systems work well.

Ample space: UASB with aerobic polishing is efficient for larger breweries.

What are your discharge limits?

Very strict (BOD < 30 mg/L): MBR provides the most reliable compliance.

Moderate (BOD 50-100 mg/L): SBR or anaerobic + aerobic combination.

Pre-treatment only: UASB alone may suffice for discharge to municipal sewer.

Is energy recovery important?

Yes - prioritise biogas: UASB or IC reactor generates 80-90% of energy needs.

Lower priority: MBR or SBR with focus on treatment performance and simplicity.

Why Choose Biological Treatment

Cost Effective

Operating requirements of -0.80/m³ are 3-5x lower than AOP. Anaerobic systems generate biogas -0.30/m³.

Environmentally Friendly

Natural process using microorganisms. Anaerobic systems produce renewable energy and minimal sludge.

Proven Technology

Decades of successful brewery applications. Predictable performance with proper design and operation.

Biogas Recovery

Anaerobic systems produce 0.3-0.4 m³ biogas per kg COD removed. Can offset 60-80% of brewery's thermal energy.

Low Sludge Production

Anaerobic systems produce 80-90% less sludge than aerobic. Reduces disposal requirements significantly.

Flexible Operation

SBR and MBR systems handle variable flows and loads common in brewery operations.

Brewery Wastewater Characteristics

High Carbohydrate Content

Spent grain, wort residues, and sugars are readily biodegradable. Perfect feedstock for advanced biological treatment with rapid BOD removal.

Yeast & Protein

Yeast cells and protein from fermentation provide nitrogen for bacterial growth. C:N ratio is typically favourable.

Temperature Variations

Hot CIP wastewater (60-80°C) requires cooling before advanced biological treatment. Heat recovery systems can be integrated.

pH Fluctuations

Acid and caustic CIP cycles create pH swings. Equalization tanks with pH control are essential for biological system protection.

Batch Discharges

Brewing cycles create intermittent high-strength flows. Equalization is critical for stable biological performance.

Colour Compounds

Melanoidins from malt roasting can persist through advanced biological treatment. May require AOP polishing for colour removal.

Related Equipment & Systems

Equalization Tanks

Flow and loading balancing essential for stable biological performance. Includes pH neutralisation.

View Tanks

DAF Systems

Pre-treatment to remove yeast and solids before advanced biological treatment, reducing organic load.

View DAF

Rotary Drum Screens

Remove spent grain and hop debris to protect downstream biological equipment.

View Screens

Screw Presses

Dewater biological sludge to 18-22% solids for efficient disposal.

View Presses

Biogas Handling

Gas collection, storage, and utilisation systems for anaerobic reactors.

Biogas Systems

Process Monitoring

Online BOD, pH, DO, and biogas analysers for optimised biological operation.

SCADA Systems

Related Pages

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Advanced oxidation processes for recalcitrant industrial organics.

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Anaerobic digestion systems for breweries and distilleries.

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Brewery Aop Treatment

Advanced oxidation processes for refractory brewery organics.

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Brewery Cider Wine

Wastewater treatment for cideries and wineries.

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Brewery Contract

Wastewater treatment for contract and multi-brand brewing facilities.

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Brewery Craft Commercial

Scaleable wastewater treatment for craft breweries, microbreweries and commercial production facilities.

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Find the right biological system for your brewery

Our engineers will analyse your wastewater and recommend the optimal Treatment Process.

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