Across the U.S., renewable natural gas (RNG) projects are gaining momentum. shows that the sector has considerable growth potential, and it identifies over 17,000 new sites that are ready for development.
The research shows that most of these sites – over 11,000 – are existing farms. Agricultural manure, food waste and other organic materials that once required costly disposal are now valuable feedstocks for anaerobic digestion and biogas production.
However, for many operators, the challenge is not producing gas, rather it is ensuring that their facilities run reliably without the need for frequent maintenance.
As more farms and regional waste processors move into biogas production, operators are finding out that variability in organic waste can cause operational instability. Fibrous materials and uneven mixing conditions can cause blockages, poor digestion performance and unplanned downtime.
As the sector is poised to expand, operational reliability will determine whether projects deliver consistent energy output or face rising maintenance costs.
Fibrous 91²Ö¿â: Disruption for Digesters
Anaerobic digestion systems rely on stable biological conditions to convert organic waste into methane-rich biogas. Maintaining those conditions requires careful management of the waste’s physical characteristics.
Organic feedstock, particularly agricultural manure and food waste, often contain fibrous materials like straw, silage and undigested feed, which can accumulate in digesters and pumps. This can lead to blockages or uneven mixing if they are not properly handled early in the process.
While feedstock preparation is important, mixing also plays a critical role in maintaining stable digestion conditions. Inside the digester, microorganisms break down organic material to produce methane.
For this process to work effectively, the contents of the digester must remain well mixed so that bacteria, nutrients and heat can all be evenly distributed. Poor mixing can create zones where solids settle and accumulate. These zones reduce the digester’s effective working volume, eventually requiring costly clean-outs.
Inconsistent mixing can also create other problems. Without effective solids suspension and heat distribution inside the digester, microbial activity becomes uneven. This can reduce gas yield, create sediment build-up and can also require more frequent system interventions.
The operational consequences can quickly add up. Routine callouts to clear blockages, unexpected shutdowns and fluctuating digestion performance can turn a promising energy project into a high-maintenance operation.
Designing RNG facilities with these day-to-day operational requirements in mind can make a significant difference when it comes to boosting long-term performance.
Engineering Consistency Into Everyday Operations
The Middleton Digester in Middleton, Wisconsin demonstrates how a community facility is helping to power the growth in RNG projects. Middleton is an anaerobic digestion facility that processes manure from nearby dairy farms. Like many digesters in agricultural settings, the facility processes straw, sawdust and undigested feed, all of which can clog up the pumps or accumulate within the digestion system if they are not properly managed.
Middleton Digester was experiencing recurring blockages and frequent maintenance issues. Service calls and repairs were at times required weekly, which disrupted operations and added to maintenance costs. To address these challenges, the facility’s operators evaluated how it handled solids and mixing as part of the digestion process.
Armed with these insights, Middleton decided to adopt a mixing and pumping configuration designed specifically to handle fibrous materials and maintain consistent flow conditions. Xylem designed the pumping and mixing approach for the facility using its Flygt submersible mixers. This configuration helps distribute heat throughout the digester while keeping solids suspended.
Chopper pumps process fibrous materials before they enter the digestion chamber, reducing the risk of clogs in downstream equipment. Materials entering the digester were uniform, blockages were eliminated and the digestion process was more predictable.
After the installation, operators reported that the pumps and mixers ran for more than a year without requiring attention. For facilities that depend on consistent gas production to meet energy agreements or supply contracts, that type of operational stability is vital.
Seamless Operations Support Viable Projects
The increase in RNG facilities across the U.S. reflects growth in the biogas sector and supports broader efforts to reduce greenhouse gas emissions. The long-term viability of these projects does not depend solely on policy incentives and feedstock availability.
To effectively capture methane and recover value from organic waste streams, facilities must operate consistently with manageable maintenance requirements and predictable performance. That means designing systems that account for variable organic waste streams and support seamless day-to-day operations.
For operators, the lessons learned from successful projects are clear. Facilities that prioritize stable feedstock handling, effective mixing and equipment that requires minimal maintenance experience fewer disruptions and have more dependable gas production.
As RNG development expands across agricultural, municipal and waste-processing sectors, these operational considerations will increasingly shape which projects deliver consistent returns. Turning organic waste into renewable energy offers enormous potential.
But as the operators of Middleton Digester know, realizing that potential depends on designing systems that can run smoothly not just on day one, but in the years ahead.