Anaerobic biological treatment is a process that uses the metabolic properties of anaerobic microorganisms to convert organic matter into methane and carbon dioxide. Anaerobic biological treatment has many advantages, including lower energy consumption, higher organic matter removal rate, and less residual sludge. This article will introduce the basic principles of anaerobic biological treatment and the basic principles of anaerobic fermentation.
1. Basic principles of anaerobic biological treatment.
The basic principle of anaerobic biological treatment is to use the metabolic properties of anaerobic microorganisms to convert organic matter into methane and carbon dioxide. In the process of anaerobic biological treatment, organic matter is transformed through three stages: hydrolysis acidification, hydrogen production to acetic acid, and methanation.
Hydrolysis acidification stage: In an anaerobic environment, macromolecular organic matter is broken down into small organic compounds, such as amino acids, monosaccharides, and fatty acids, by the action of hydrolase enzymes. These small organic molecules then enter the hydrogen-producing acetic acid production stage.
Hydrogen production and acetic acid production stage: In this stage, small molecule organic matter is converted into acetic acid and hydrogen under the action of hydrogen-producing acetic acid-producing bacteria. At the same time, some acetic acid is further converted to methane. This stage is the most critical step in the anaerobic biological treatment process, as it serves as a bridge between the hydrolytic acidification stage and the methanation stage.
Methanation stage: In the methanation stage, acetic acid and hydrogen are converted into methane and carbon dioxide. This process is done by a group of special anaerobic microorganisms called methanobacteria. Methanobacteria grow slowly and reproduce slowly in anaerobic environments, so adequate reaction time and good environmental conditions are required to guarantee their growth and metabolism.
2. The basic principle of anaerobic fermentation.
Anaerobic fermentation refers to the process in which organic matter is converted into a stable substance through fermentation without the participation of oxygen, and at the same time energy is released. Anaerobic fermentation can be divided into three stages: hydrolytic fermentation stage, hydrogen production and acetic acid production stage, and methane production stage.
Hydrolysis and fermentation stage: In this stage, macromolecular organic compounds such as cellulose and proteins are converted into small organic compounds, such as amino acids, monosaccharides and fatty acids. This process requires the action of enzymes and produces products such as carbon dioxide, ammonia, and water.
Hydrogen production and acetic acid production stage: In this stage, small molecule organic matter is converted into acetic acid and hydrogen under the action of hydrogen-producing acetic acid-producing bacteria. At the same time, some acetic acid is further converted to methane. This process is the most critical step in the anaerobic fermentation process, as it serves as a bridge between the hydrolytic fermentation stage and the methanogenic stage.
Methanogenic Stage: In the methanogenic phase, acetic acid and hydrogen are converted into methane and carbon dioxide. This process is done by methanobacteria. Methanobacteria grow slowly and reproduce slowly in anaerobic environments, so adequate reaction time and good environmental conditions are required to guarantee their growth and metabolism.
In summary, both anaerobic biological treatment and anaerobic fermentation are processes that use the metabolic properties of anaerobic microorganisms to transform organic matter. In anaerobic biological treatment, organic matter is converted into methane and carbon dioxide; In the anaerobic fermentation process, organic matter is converted into a more stable substance and energy is released. In practical application, according to different treatment objectives and conditions, different anaerobic treatment processes can be selected to achieve the effective conversion of organic matter and the best utilization of energy.