Microbial-Electrochemical Systems for Culled Tomato Waste Treatment
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Solution Overview
Problem
Conventional biotechnologies are inefficient in optimizing energy production from culled tomatoes, as they require significant energy inputs and face challenges such as stringent regulations, odor and dust issues, and the need for purification steps in anaerobic digestion and dark fermentation processes.
Innovation Solution
The use of microbial-electrochemical systems (MESs) that leverage the redox-active mediators in culled tomatoes, such as carotenoids and flavanoids, to catalyze extracellular electron transfer and generate electricity, combined with strategies like mixing culled tomatoes with dilute wastewaters to drive the MESs and generate electricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional biotechnologies such as anaerobic digestion or dark fermentation are used to process culled tomatoes, then energy production is achieved, but purification steps are required and energy inputs are significant
Solution Approach 1:
The patent extracts and utilizes the redox-active mediators naturally present in culled tomatoes (such as carotenoids, flavanoids, and other phenolic compounds) to directly catalyze electron transfer to the anode, eliminating the need for complex purification steps required in conventional anaerobic digestion and dark fermentation processes. This extraction approach converts the previously underutilized tomato waste components into functional catalysts that simplify the overall system.
Solution Approach 2:
The patent introduces redox-active mediators as intermediary substances that facilitate electron transfer between the organic matter in culled tomatoes and the anode. These mediators (carotenoids, flavanoids, etc.) act as electron shuttles, enabling direct electrochemical oxidation without requiring complex biological digestion systems and subsequent purification infrastructure, thereby reducing device complexity while maintaining energy production.
2Reliability
If activated sludge processes are used for treating culled tomatoes, then treatment is achieved, but significant energy inputs are required
Solution Approach 1:
The patent enables the culled tomato waste to treat itself through auto-catalytic electrochemical oxidation. The redox-active mediators naturally present in the tomato waste catalyze their own oxidation and the oxidation of other organic components, generating electricity in the process. This self-service mechanism eliminates the need for external energy inputs required by activated sludge processes, while maintaining reliable treatment effectiveness.
Solution Approach 2:
The patent replaces the mechanical and biological aeration systems of activated sludge processes with an electrochemical system driven by natural redox reactions. Instead of requiring energy-intensive mixing, aeration, and biological degradation followed by mechanical separation, the system uses spontaneous electron transfer mediated by redox-active compounds, substituting complex mechanical-biological infrastructure with a simpler electrochemical approach that reduces energy consumption while ensuring reliable treatment.
3Loss of substance
If land application of culled tomatoes is used, then disposal is achieved, but stringent regulations make it unattractive
Solution Approach 1:
The patent fundamentally changes the parameter of culled tomato waste from a disposal problem to an energy resource. By applying electrochemical oxidation with redox-active mediators, the system transforms organic waste into electrical energy, changing the status of the material from something requiring regulated disposal to a valuable feedstock. This parameter change from waste management to energy production eliminates regulatory barriers associated with land application while achieving complete oxidation and elimination of organic matter.
4Reliability
If on-site composting is used for culled tomatoes, then treatment is achieved, but expensive equipment and lengthy treatment periods are required
Solution Approach 1:
The patent replaces the lengthy biological composting process with rapid electrochemical oxidation. Instead of requiring weeks or months of aerobic decomposition with expensive turning and aeration equipment, the electrochemical system with redox-active mediators achieves complete oxidation of organic matter in hours or days. This substitution of biological-mechanical composting with direct electrochemical oxidation dramatically reduces treatment time while maintaining reliable elimination of organic contaminants, eliminating the need for expensive composting infrastructure.
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 enhances the performance of MESs by overcoming impedance issues and achieving higher power densities and current densities, outperforming pure chemical substrates and municipal wastewater, while reducing treatment costs and environmental impacts.
Implementation Method 1
culled tomatoes containing a variety of redox-active species such as carotenoids, kampferol, malvin, myricetin, naringenin, naringin, petunidin, quercetin, and riboflavin qualifying as redox-active mediators in MESs
Implementation Method 2
redox-active mediators catalyze extracellular electron transfer from anode-respiring bacteria to solid electrodes in MESs
Implementation Method 3
the oxidation power in the anode to complete the circuit
Data Source
AI summary
The United States faces significant environmental burden to treat and transport ˜0.61 billion kg of defective tomatoes (culled tomatoes) every year. The present disclosure provides for the treatment and processing of culled tomatoes in microbial-electrochemical systems, using the microbial fuel cell as a model reactor. The fundamental differences between the long-term oxidative behavior of unprocessed culled tomatoes compared to the three readily soluble substrates (dextrose, acetate, and wastewater) are disclosed. AC electrochemical impedance spectroscopy (EIS) analyses indicate the influential impedance contributions of the peel & seed to the cull oxidation. Cyclic voltammetry tests indicate that the indigenous redox-active pigments in the cull influence the faradaic processes involved in the cull oxidation.