About this Course

Anaerobic digestion is a complex biochemical reaction carried out in a number of steps by several types of microorganisms that require no oxygen to live. This reaction produces biogas, which is primarily composed of methane and carbon dioxide.

The Anaerobic Digestion Process in an anaerobic environment, specialized microorganisms break down complex organic matter (carbohydrates, proteins, and fats) into molecules with a smaller atomic mass that are soluble in water (sugars, amino acids, and fatty acids). Methane and carbon dioxide are the primary end products of this process, which is known as biogas. More importantly, anaerobic digestion stabilizes the slurry in the digester.

The overall conversion process of complex organic matter into methane and carbon dioxide can be divided into four steps, namely hydrolysis, acidogenesis, acetogenesis and methanogenesis. It should be pointed out that some researchers combine the acidogenesis and acetogenesis steps and make it a three step conversion process.

This module provides information on the start-up, operation and control of a digester, and sets forth the reasons why digesters fail. Included in this module are standards for best operating procedures and safe operation of digesters.

Learning Outcomes & Objectives:

• Explain the process for starting a digester.
• Explain aspects of digester operation and control to clients.
• Suggest potential reasons for digester malfunction.
• Work with farmers to develop best operating practices for their digester.
• Understand the safety issues when operating a digester.