CONTROL OF AN ANAEROBIC MESOPHILIC REACTOR USING PERIODIC TEMPERATURE VARIATIONS

In this study, temperature variations in a mesophilic anaerobic reactor were used to control the reactor degradation capacity. When the reactor temperature was periodically changed from 32°C to 46°C with a period of 12 h, a near liner increase in methane production in response to temperature augmentation was observed. Furthermore, when the reactor temperature was increased during increased organic load, it resulted in a lower effluent concentration of volatile fatty acids and an increased chemical oxygen demand (COD) removal rate. A feedback control algorithm, which was based on a multi-model observer-based estimator of the anaerobic digestion process, was developed. The algorithm increased reactor temperature in response to increasing effluent COD concentration. It was successfully tested in a 10 L laboratory-scale reactor.