An anaerobic digester is a continuous biological process, not a machine you can stop and restart on a whim. Feed rate, temperature, mixing and gas handling all have to stay in a narrow band, around the clock. The controls side is close to the organics and composting work Strule started in, and the same discipline carries across: stabilize the loop first, make the trend visible, and never treat an alarm as noise until you’ve checked what it’s actually reporting.

What’s different here is the gas. Biogas handling, flare and CHP interfaces, and the gas-detection and classified-area I/O around them are safety-critical, not just process instrumentation. An interlock that’s been bridged out or a detector that’s drifted uncalibrated is a real hazard, not a nuisance trip. Feed and mixing control that hunts, temperature loops that drift, and level excursions all show up first as poor gas quality or reduced output, long before anyone traces it back to the loop that’s actually unstable. We stabilize the process, rationalize the alarms around the genuinely safety-critical points, and respect the classified-area rules on every piece of work.

A common example: a foam or level excursion in the digester tank is more than a nuisance. It can plug a gas line or force an emergency flare event if the interlock chain doesn’t catch it in time. Getting the level and pressure instrumentation trustworthy, and making sure the logic between digester, gas train and CHP or flare genuinely agrees on what state the system is in, is usually worth more than chasing the fault of the week.

Equipment we work on