Florida Wastewater Practice Test

What is the first step in anaerobic digestion known as?

1. Fermentation

2. Acid formation

3. Methanogenesis

4. Hydrolysis

The correct answer is: Acid formation

The first step in anaerobic digestion is hydrolysis. During hydrolysis, complex organic materials—such as fats, proteins, and carbohydrates—are broken down into simpler compounds like fatty acids, amino acids, and sugars. This process is crucial because it sets the stage for the subsequent steps of anaerobic digestion, which include acid formation and methanogenesis. Hydrolysis is typically carried out by a variety of microbial species that secrete enzymes to facilitate the breakdown of these complex substances. Without hydrolysis, the processes that follow would not have the necessary simple substrates to transform into biogas components, such as methane. Understanding hydrolysis is essential for comprehending the overall anaerobic digestion process, as it highlights the importance of breaking down larger, more complex molecules into smaller ones that are more easily processed by microorganisms in the later stages of digestion. By recognizing hydrolysis as this foundational step, one can better appreciate how each subsequent step builds upon the results of the earlier stages in producing biogas in wastewater treatment systems.