Overview

Facility Type: Midwest agricultural biogas facility

Feedstock: Food waste and manure

Challenge: Frequent digester cleanouts, rising costs, reduced active volume

EF3 Solution: Drycake® Twister depackaging and separation system

The Challenge: Digester Cleanouts Caused by Contaminated Feedstock

A Midwest agricultural biogas facility found itself stuck in a costly cycle. Grit, plastics, and packaging from food waste were accumulating in the digester, forcing full cleanouts every year.

Each cleanout cost between $85,000 and $110,000, averaging nearly $100,000 annually, while also reducing active digester volume and limiting biogas production. Beyond the financial hit, frequent shutdowns disrupted operations and constrained long-term performance.

Rather than treating cleanouts as unavoidable, the facility looked upstream where the real problem started.

The Solution: Food Waste Pretreatment Before Anaerobic Digestion

Rather than continuing to manage costly cleanouts, the facility addressed the root cause: poor pretreatment upstream of the digester.

The plant installed a Drycake Twister depackaging system, paired with downstream separation equipment, to remove contaminants from food waste before anaerobic digestion.

Drycake Twister Pretreatment System Capabilities

  • Separates organic material from packaging
  • Removes plastics, grit, and dense inerts
  • Designed for highly contaminated food waste streams
  • Produces cleaner, more consistent digester feedstock
  • Protects digesters from excessive solids accumulation

By preventing contamination from entering the digester, the system allowed the anaerobic digestion process to operate closer to its designed capacity.

Results: Improved Digester Performance and Higher Biogas Output

The impact of proper pretreatment was immediate and measurable.

Reduced Digester Cleanout Frequency

  • Before: Once per year
  • After: Once every 3.5 years

Lower Digester Maintenance Costs

  • Before: ~$97,500 per year
  • After: ~$37,100 per year
  • Cost reduction: 62%

Increased Biogas Production

  • 22% increase in biogas output, driven by restored active digester volume and improved mixing

Return on Investment

  • Full ROI achieved in 30 months

Why Pretreatment Is Critical for Anaerobic Digestion Systems

This project highlights a key lesson for biogas and anaerobic digestion operators:

Frequent digester cleanouts are rarely caused by biology.

They are almost always caused by inadequate feedstock pretreatment.

When food waste depackaging and contaminant removal are handled upstream, digesters can focus on producing renewable energy not separating plastics and grit.

The eFACTOR3 Perspective

As a North American distributor of Drycake food waste depackaging and pretreatment systems, eFACTOR3 helps biogas and organics facilities:

  • Reduce digester cleanouts
  • Improve biogas production
  • Lower operating and maintenance costs
  • Process highly contaminated food waste more effectively

This case study demonstrates the operational and economic benefits of installing the right pretreatment system ahead of anaerobic digestion.

If your facility is:

  • Cleaning digesters every 1–2 years
  • Experiencing declining biogas output
  • Processing food waste with high plastic contamination

EF3 can help you evaluate pretreatment options and quantify the operational and economic impact.

Learn more about Drycake solutions