How One Biogas Plant Cut Digester Cleanout Costs by 62% and Increased Gas Output by 22%

A Midwest agricultural biogas facility processing food waste and manure was facing a problem many plants quietly accept as “normal.” Their digester required a full cleanout every year. Each shutdown cost between $85,000 and $110,000, not including the operational disruption and lost energy revenue that came with frequent downtime. 

Annual cleanouts feel routine only until you annualize the true burden. At the midpoint of their cost range, the plant was spending about $97,500 every year simply to remove grit, plastics, and rags that should never have reached the digester in the first place. 

Instead of treating cleanouts as an unavoidable recurring cost, the facility addressed the root cause: contamination entering with feedstock. They installed a Drycake Twister depackaging system with downstream separation equipment designed to protect digesters from plastics, grit, and dense inert solids. The total investment was $520,000. 

The change was immediate and measurable. 

First, the digester stopped filling with non digestible material. Cleanouts shifted from an annual crisis to a planned event every 3.5 years. Each cleanout is now more comprehensive and costs approximately $130,000, but because it happens far less often, the annualized cost dropped sharply. 

Here is the math: 

– Before: annual cleanout cost averaged $97,500 per year. 

– After: $130,000 every 3.5 years equals about $37,100 per year. 

– Result: a 62% reduction in annual cleanout costs. 

Second, digestion efficiency improved. With fewer dead zones and less grit accumulation, mixing became more effective and active volume was restored. Biogas production increased by 22%, creating additional revenue while also improving plant stability. 

The combined impact of reduced cleanout spending, higher gas output, and fewer downtime events delivered a full return on investment within 30 months. 

This case reinforces a simple operational truth. Frequent digester cleanouts are rarely a biological problem. They are usually a feedstock and pretreatment problem. When grit and plastics are stopped upstream, the digester shifts back into its intended role: producing biogas reliably, not acting as a trash separator. 

If your plant is cleaning every 1 to 2 years, or if gas production trends down while mixer energy trends up, you may already be operating on reduced active volume. Send us your last cleanout cost and interval. We will help you benchmark your annualized burden and map your path to a longer, more stable cleaning cycle. 

Contact Drycake: america@drycake.com | +1 843 894 7837