Two-Stage Anaerobic Digester Temperature Control
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Solution Overview
Problem
Current anaerobic digestion systems for organic matter are not suitable for domestic use due to the presence of pathogenic microorganisms and inefficient methane production, often resulting in unpleasant odors and incomplete conversion of organic materials to methane.
Innovation Solution
A two-stage anaerobic digestion apparatus with a refrigerated or heated first chamber to suppress methanogenesis, allowing hydrolysis, acidogenesis, and acetogenesis to occur while methanogenesis predominantly takes place in a separate chamber, optimizing process parameters for enhanced methane output and minimizing odors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-chamber anaerobic digestion system is used, then the device complexity is reduced, but the methane production efficiency decreases and pathogenic microorganisms cannot be controlled
Solution Approach 1:
The anaerobic digestion system is divided into two separate chambers: a first chamber for hydrolysis, acidogenesis, and acetogenesis; and a second chamber for methanogenesis. This segmentation allows each chamber to be optimized for its specific function, improving overall methane production efficiency while enabling better control of pathogenic microorganisms in the first chamber.
Solution Approach 2:
The methanogenesis process is extracted and separated from the other anaerobic digestion stages. By taking out the methanogenic archaea and their specific environmental requirements into a separate second chamber, the system achieves more complete conversion of organic matter to methane while allowing the first chamber to focus on breaking down complex organic materials without the constraints of methanogenic conditions.
2Productivity
If pathogenic hydrolytic microorganisms are used in commercial anaerobic digesters, then the hydrolysis of organic matter is enhanced, but the system becomes unsafe for domestic use and produces unpleasant odors
Solution Approach 1:
The system converts the potential harm of pathogenic microorganisms into a benefit by separating their function from their harmful effects. Non-pathogenic hydrolytic microorganisms are used in the first chamber to perform the necessary hydrolysis, while the separate second chamber captures and processes the organic matter efficiently, preventing odor generation and ensuring safety for domestic use.
Solution Approach 2:
The system changes the biological parameters by selecting non-pathogenic hydrolytic microorganisms and controlling environmental conditions (temperature, pH, retention time) in each chamber to optimize performance while eliminating pathogenicity. This parameter control ensures safe operation in domestic settings without compromising hydrolysis efficiency.
3Productivity
If temperature is controlled to suppress methanogenesis in the first chamber, then the conversion of organic matter to intermediate products is optimized, but energy is consumed for refrigeration or heating
Solution Approach 1:
The first chamber performs preliminary action by completing hydrolysis, acidogenesis, and acetogenesis before the organic matter is transferred to the second chamber for methanogenesis. This preliminary processing optimizes the substrate for methanogenic archaea, ensuring more complete conversion to methane in the second chamber and reducing the need for continuous energy-intensive temperature control.
Solution Approach 2:
The system uses periodic action by transferring organic matter between chambers at optimized intervals. The first chamber operates under conditions favorable for hydrolysis and acidogenesis for a set period, then material is transferred to the second chamber for methanogenesis. This periodic operation allows temperature control to be applied only when necessary, reducing overall energy consumption while maintaining high conversion efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables more complete conversion of organic matter to methane, reduces unpleasant odors, and provides a safe and efficient method for domestic anaerobic digestion, utilizing non-pathogenic microorganisms for improved biogas production.
Implementation Method 1
The temperature of the first chamber is refrigerated or heated (typically regulated) to a temperature which suppresses methanogenesis in the first chamber
Implementation Method 2
methanogenesis takes place predominantly in the second chamber
Implementation Method 3
the biochemical hydrolysis of organic polymers (such as carbohydrates and proteins) into small organic molecules
Implementation Method 4
The apparatus is typically configured to move organic matter from the first chamber to the second chamber and from the second chamber to the first chamber
Data Source
AI summary
Anaerobic digestion apparatus comprises a first chamber for retaining organic matter before and/or during anaerobic digestion and a second chamber for retaining organic matter during anaerobic digestion. The anaerobic digestion apparatus is configured to refrigerate or heat the first chamber to suppress methanogenesis in the first chamber. The anaerobic digestion apparatus comprises a controller programmed to regulate the anaerobic digestion process and to thereby reduce system perturbations. The flow of organic matter to the second chamber where methanogenesis is regulated. There is disclosed an inoculum for anaerobic digestion comprising Acetobacterium woodii and Methanosaeta concilii.