Microbial Electrolysis Cell Nutrient Feeding for Continuous Methane Output
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Solution Overview
Problem
The continuous production of methane using methanogenic microorganisms in microbial electrolysis cells is hindered by the need for continuous nutrient supply, which is costly and does not meet the specific nutrient requirements of different strains, leading to inefficiencies and high operational costs.
Innovation Solution
A method involving a separated nutrient feeding strategy, where nitrogen and sulfur sources are supplied discretely or continuously, along with an inorganic carbon source, to optimize the bio-electrochemical process, allowing for a scalable and reliable methane production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous nutrient supply is used to maintain methanogenic microorganisms, then methane production continues, but operational costs increase and chemical waste increases
Solution Approach 1:
The patent implements periodic feeding cycles where nutrients are supplied in discrete pulses rather than continuously. The system alternates between feeding phases (supplying carbon, nitrogen, and sulfur sources) and starvation phases (no nutrient supply), allowing methanogens to maintain activity through stored intracellular reserves during starvation periods. This periodic action reduces chemical waste while sustaining methane production.
Solution Approach 2:
The methanogenic microorganisms utilize their own intracellular storage compounds (polyhydroxyalkanoates and sulfur granules) accumulated during feeding phases to sustain metabolism during starvation phases. This self-service mechanism allows the culture to maintain methane production without external nutrient supply for extended periods, reducing operational costs and chemical waste.
2Productivity
If continuous nutrient supply is used to maintain methanogenic microorganisms, then methane production continues, but operational costs increase
Solution Approach 1:
The system employs periodic feeding cycles with alternating feeding and starvation phases, reducing the frequency and amount of nutrient purchases and handling. This approach maintains methane production continuity while significantly reducing operational costs associated with continuous nutrient supply.
Solution Approach 2:
Methanogenic microorganisms serve themselves by utilizing intracellular storage compounds to maintain metabolism during starvation phases, eliminating the need for continuous external nutrient supply and associated operational costs.
3Adaptability or versatility
If standard culture medium is used to supply nutrients, then general microbial needs are met, but specific strain requirements are not optimized
Solution Approach 1:
The nutrient supply system is segmented into separate feeding streams for different nutrient types (carbon source, nitrogen source, sulfur source). This segmentation allows independent optimization of each nutrient's timing and concentration according to specific methanogen strain requirements and physiological states, improving methane production efficiency while maintaining operational flexibility.
Solution Approach 2:
The patent implements location-specific and time-specific nutrient optimization by adjusting the composition and timing of carbon, nitrogen, and sulfur supplies based on the specific methanogen strain's physiological state and growth phase. Different phases of the periodic feeding cycle receive tailored nutrient compositions optimized for either growth or methane production.
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
This approach increases the overall efficiency of methane production by 30% or more, reduces chemical waste, and lowers operational costs by adapting nutrient supply to the needs of methanogenic microorganisms, achieving high coulombic efficiency and flexible process operation.
Implementation Method 1
methanogenic microorganisms reside e.g. at the cathode ('bio-cathode')... the methanogenic microorganisms reside e.g. at the cathode ('bio-cathode'). The reactor may comprise a single compartment, or the cathodic compartment, or chamber, may be separated from the anodic compartment, or chamber, e.g. via a semipermeable membrane.
Implementation Method 2
electrical power is used to enhance the potential difference between the anode and the cathode of MEC to enable the bio-electromethanation reaction
Implementation Method 3
the electron flow required for the cathodic reduction of classical CO2 to methane is formed in the anode compartment by water oxidation... the culture may also catalyse the methanation reaction via an intermediated redox mediator
Data Source
AI summary
The present invention refers to a method to produce methane or at least one other synthesis product by methanogenic microorganisms in a microbial electrolysis cell (MEC), while applying a separated nutrient feeding supply in a discrete or a continuous manner.