Anaerobic Digestion Startups and Process Changeovers for Class A and Advanced Processes

Anaerobic digestion startups and digestion process changeovers have often been described as difficult. This is becoming more pronounced in recent years with the advent of various advanced digestion and Class A systems, which are typically more highly loaded and can be more susceptible to adverse influence. Several case histories are presented here to show how agencies have handled advanced and Class A digestion startups and process changeovers. In some cases, serious problems including structural damage have occurred as agencies and owners struggle to respond to foaming and gas holdup events. New startup tools and information are also discussed to help alert plant operators and engineers to find better solutions.