Uric Acid Nitrogen Source for Groundwater Bioremediation
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Solution Overview
Problem
Conventional nitrogen amendments for bioremediation of LNAPL and DNAPL contaminants are inefficient due to high solubility and rapid release, leading to low bioavailability and increased operational costs, especially in groundwater systems where DNAPLs are recalcitrant to conventional remedial technologies.
Innovation Solution
The use of uric acid and uric acid-containing materials as slow-releasing nitrogen sources with affinity for hydrocarbons, which are insoluble in water and release nitrogen slowly, enhancing microbial activity and biodegradation processes by adjusting the carbon-to-nitrogen ratio and electron acceptor concentrations in contaminated groundwater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional highly soluble nitrogen amendments (ammonium nitrate, urea) are used, then nitrogen is readily available to microbes, but nitrogen is released too quickly and lost through denitrification and leaching, requiring frequent reapplication
Solution Approach 1:
The patent changes the solubility parameter of nitrogen amendments from highly soluble (conventional) to low solubility (insoluble). Insoluble nitrogen sources such as nitrogen-containing polymers, coated fertilizers, or organic matter are used to provide slow-release nitrogen that remains in the groundwater system longer, reducing denitrification losses and eliminating the need for frequent reapplication while maintaining reliable nitrogen availability to microbes.
Solution Approach 2:
The patent implements dynamic nitrogen release by using insoluble nitrogen sources that gradually dissolve or decompose over time, providing a sustained release profile matched to microbial consumption rates. This dynamic release mechanism prevents both nitrogen deficiency and excessive loss, optimizing the balance between availability and retention in the groundwater system.
2Reliability
If soluble nitrogen fertilizers are applied frequently to maintain biodegradation, then nitrogen availability is maintained, but operational costs increase
Solution Approach 1:
The patent changes the release rate parameter of nitrogen from fast-release (soluble fertilizers requiring frequent application) to slow-release (insoluble sources). This single parameter change simultaneously maintains biodegradation effectiveness by providing sustained nitrogen availability while dramatically reducing operational costs by eliminating frequent reapplication requirements.
Solution Approach 2:
The patent implements self-service nitrogen delivery through insoluble sources that automatically release nitrogen at rates matched to microbial consumption. The system self-regulates nitrogen supply without human intervention, maintaining effective biodegradation while eliminating the operational burden and costs of frequent manual reapplication.
3Reliability
If conventional nitrogen amendments are used for DNAPL degradation, then some nitrogen is provided, but efficiency is very low due to solubility mismatch between amendments and DNAPL
Solution Approach 1:
The patent changes the solubility parameter of nitrogen amendments to match the low-solubility characteristics of DNAPL contaminants. Insoluble nitrogen sources create a solubility match with DNAPL, enabling nitrogen to be released at the contaminant-water interface where it is most needed, thereby dramatically improving degradation efficiency while maintaining reliable nitrogen provision.
Solution Approach 2:
The patent applies nitrogen locally at the DNAPL-water interface through insoluble nitrogen sources that release nitrogen in situ. This localized application ensures nitrogen is provided precisely where DNAPL degradation occurs, maximizing degradation efficiency while maintaining reliable nitrogen availability at the contamination site.
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 accelerates the biodegradation of LNAPL and DNAPL contaminants by providing a sustained nitrogen source, improving microbial activity and degradation rates, and reducing the need for frequent amendments, thereby lowering operational costs and enhancing the effectiveness of bioremediation.
Implementation Method 1
Urea may be considered as a slow-releasing N fertilizer since it may undergo hydrolysis before ammonium can be released
Implementation Method 2
Nitrate (NO3−) may be a preferred N nutrient, as well as an electron acceptor, for anaerobic microbes to degrade hydrocarbons via denitrification
Implementation Method 3
Aerobic degradation dominates LNAPL remediation
Implementation Method 4
The use of uric acid and uric acid-containing materials as slow-releasing nitrogen sources with affinity for hydrocarbons
Data Source
AI summary
Systems and methods for co-enhancing contaminant degradation such as LNAPL and DNAPL degradation. Embodiments of the inventive technology may relate to assuring adequate amounts (e.g., concentrations) of certain substances (e.g., nitrogen, electron acceptor, bacteria, microbial substrate) so that degradation of LNAPL and DNAPL is enhanced as intended. Any of the inventive methods may involve the amendment of groundwater with one or more particular substance (uric acid, electron acceptors, microbial substrate, as but a few examples) in order to enhance DNAPL, and perhaps also, LNAPL degradation.