Instrumentation and Control in Anaerobic Digestion

Abstract

Anaerobic digestion is a multistep process, and is most applied to solids destruction and wastewater treatment for energy production. Despite wide application, and long-term industrial proof of application, some industries are still reluctant to apply this technology. One of the classical reasons has been lack of process control handles, instruments, and developed control algorithms. This has improved dramatically in the past 10 years, and all of these areas have now been addressed. The main gap in instrumentation technology has been a rapid intermediate sensor to detect overload conditions. There are now a number of sensors that can measure total or individual organic acids, and some are in commercial production. Control has also been widely applied, with a wide variety of controllers, for direct beneficial results, and one application has been shown in this paper. Available control handles are still a limitation, but this is being partly addressed by the increased complexity of digestion processes. Methods for control benchmarking have also been improved, as there is now an industry standard model (the IWA ADM1), and this is being applied in an improved whole wastewater treatment plant benchmark. There has therefore been, overall, a quantum advance in application and sophistication of instrumentation and control in anaerobic digestion, and it is an effective option for improved process loading rate and conversion efficiency