Double Zigzag Air Classifier System for SRF Material Separation

Client: UK-Based Waste Management Company

Sector: Waste & Recycling

Solution: Double Zigzag Air Classifier System (ZAC1200)

Focus: Separation of Heavy Materials from Finished SRF

The Challenge

A UK-based waste management company required an efficient solution to separate heavy materials such as glass and stone from finished Solid Recovered Fuel (SRF). The input material had the following characteristics:

Material Input: Finished SRF

Particle Size: 5 – 35 mm

Bulk Density: Approximately 140 kg/m³

Heavy Material Content: Glass and stone constituting approximately 2.5% – 5% of input

Light Material: Dried SRF

The client needed a system capable of processing around 14 tonnes per hour, split across two classifier units, to ensure precise separation and maintain fuel quality.

The Solution

Impact Air Systems engineered and installed a Double Zigzag Air Classifier System (2 x 1200 ZACS) tailored for this specific application, designed to efficiently separate heavier glass and stone particles from the lighter dried SRF.

System Details:

• Two 1200mm wide Zigzag Air Classifier Systems operating in parallel
• Designed for an hourly throughput of approximately 14 tph total (~7 tph per unit)
• Handles mixed bulk density material at 140 kg/m³ (~33 cubic meters per hour)
• Dual-stage zigzag chambers with adjustable airflow for optimised separation
• Robust construction for continuous operation in demanding waste processing environments

How It Works

1. Finished SRF feed is evenly distributed between the two ZACS units.

2. Inside each zigzag classifier, carefully controlled airflow separates the materials by density.

3. Heavy particles (glass, stone) are directed downward for extraction.

4. Lighter dried SRF particles are separated and sent onward as the clean output fuel material.

The Results

Post-installation, the client achieved:

• Precise separation of 2.5% – 5% heavy materials (glass and stone) from the SRF stream
• Consistent throughput meeting the requested 14 tph split across both units
• Maintained high quality dried SRF output free from heavy contaminants
• Improved overall plant efficiency by reducing manual sorting and contamination issues
• Reliable, low-maintenance operation suited for continuous processing

Environmental Impact

Efficient separation of heavy contaminants like glass and stone from SRF improves fuel quality, optimises combustion efficiency, and supports sustainability goals by reducing waste and promoting cleaner energy production.

Conclusion

With this custom-engineered Double Zigzag Air Classifier System, Impact Air Systems enabled the client to:

• Process finished SRF at high throughput rates
• Effectively remove heavy materials without compromising fuel quality
• Enhance operational efficiency and material recovery
• This project demonstrates Impact’s expertise in delivering tailored air classification solutions for complex waste processing challenges.

Interested in upgrading your SRF processing line?

Contact Impact Air Systems for expert advice and custom solutions.