Anaerobic Biodegradation of LNAPL via Targeted Amendments
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Solution Overview
Problem
Current bioremediation technologies are ineffective and costly for stimulating and sustaining the anaerobic biodegradation of light non-aqueous phase liquid (LNAPL) due to limitations in solubility and oxygen distribution in subsurface environments, and existing methods often require costly chemical or physical enhancements that can have negative consequences.
Innovation Solution
A method involving the introduction of bioremediation amendments such as sulfate, nitrate, phosphorous, and trace metals into specific locations and depths to stimulate and sustain anaerobic biodegradation, using slow release sources and targeted injection techniques to maintain optimal conditions for LNAPL biodegradation, without the need for costly chemical or physical enhancements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If aerobic biodegradation is enhanced by introducing oxygen, then hydrocarbon degradation rate is improved, but oxygen distribution in subsurface becomes difficult and cost increases
Solution Approach 1:
Instead of introducing oxygen to stimulate biodegradation (aerobic approach), the patent inverts the approach by creating anaerobic conditions and using alternative electron acceptors (nitrate, sulfate, ferric iron, manganese oxides) to achieve hydrocarbon degradation without oxygen, thereby avoiding oxygen distribution difficulties
Solution Approach 2:
The patent changes the biochemical parameters of the remediation system by shifting from aerobic to anaerobic metabolism, utilizing alternative electron acceptors to maintain microbial activity and hydrocarbon degradation rates without requiring oxygen introduction
2Reliability
If chemical oxidation or physical heating methods are used to enhance LNAPL recovery, then degradation effectiveness is improved, but remediation cost increases significantly
Solution Approach 1:
The patent employs indigenous microorganisms already present in the contaminated environment to perform the degradation work, eliminating the need for expensive external chemical oxidants or energy-intensive heating systems. The system uses naturally occurring microbial communities combined with electron acceptor addition to achieve self-sustaining biodegradation
Solution Approach 2:
The patent uses relatively inexpensive electron acceptor compounds (such as nitrate, sulfate salts) that can be added to stimulate anaerobic biodegradation, replacing costly chemical oxidation agents or energy consumption associated with thermal methods
3Productivity
If surfactants or solvents are used to enhance LNAPL solubility and biodegradation, then biodegradation rate is improved, but hydrocarbon mobilization outside treatment areas occurs and biodegradation inhibition is observed
Solution Approach 1:
The patent converts the previously harmful anaerobic conditions (which were thought to limit biodegradation) into a beneficial pathway by demonstrating that anaerobic microorganisms can effectively degrade hydrocarbons using alternative electron acceptors, eliminating the need for surfactants or solvents that cause mobilization and inhibition problems
4Quantity of substance
If pumping and extraction methods are used to recover LNAPL, then LNAPL recovery is improved, but residual LNAPL remains held by capillary forces and long-term pumping reaches diminishing returns
Solution Approach 1:
The patent applies bioremediation treatment to degrade residual LNAPL in situ before it can cause significant environmental harm, eliminating the need for long-term pumping operations. By stimulating biological degradation, the system removes the residual contaminant source that pumping methods cannot access
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 effectively degrades residual LNAPL by leveraging indigenous anaerobic microorganisms, reducing toxicity and ecological threats, and allows for a more rapid transition to monitored natural biodegradation and attenuation, making it economically applicable at a large scale.
Implementation Method 1
stimulate and sustain the anaerobic biodegradation of light non-aqueous phase liquid (LNAPL)
Implementation Method 2
the anaerobic biodegradation of a wide variety of hydrocarbons is known to occur with varied soluble electron acceptors including nitrate and sulfate
Implementation Method 3
the anaerobic biodegradation of a wide variety of hydrocarbons is known to occur with varied soluble electron acceptors including nitrate and sulfate, with insoluble ferric iron and manganese oxides
Data Source
AI summary
A method for treating LNAPL source zones using a cost effective LNAPL source zone technology to degrade residual LNAPL, by introducing bioremediation amendments comprising nutritional supplements in quantities, locations, and depths required to stimulate and sustain the anaerobic biodegradation of an LNAPL source zone; monitoring the LNAPL source zone for adverse conditions that decrease anaerobic LNAPL biodegradation; eliminating any identified adverse conditions to sustain LNAPL biodegradation; and maintaining the water with nutritional supplements in quantities, locations, and depths required to stimulate and sustain the anaerobic biodegradation of LNAPL.