Anaerobic Digestion: Factors Affecting Anaerobic Digestion Process

Abstract

Anaerobic digestion (AD) is a biological decomposition process that occurs in the absence of oxygen. The decomposition of organic matter is a multi-step process of series and parallel reactions namely hydrolysis, acidogenesis, acetogenesis and methanogene. Most of the control in anaerobic digestion is undertaken directly by the microorganisms themselves; however, the operational conditions such as temperature, pH, essential trace nutrients and toxicants can play a major role in modifying reaction rates of individual sub-processes. The energy performance of the anaerobic digestion is depending mainly on the biogas production technology, raw materials and geographic location (ambient temperature). Since the feedstocks coming to anaerobic digestion have usually lower heating value as received, the usual energy efficiency calculation used for incineration plant is not useful. Most commonly used method is the input/output method, and the estimation is dependent upon the chosen system boundary.