Advanced Oxidation Process for Selenium Removal in Mine Water
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Solution Overview
Problem
Current methods for treating mine impacted water (MIW) do not effectively utilize advanced oxidation processes (AOP) to oxidize selenium species to the least bioavailable selenate form, which is essential for reducing selenium bioavailability in aquatic environments.
Innovation Solution
The process involves subjecting MIW to an advanced oxidation process using ultraviolet light and ozone or ozone and hydrogen peroxide to oxidize selenium species to selenate, followed by the removal of residual oxidants to produce treated water with reduced selenium bioavailability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If biological treatment processes are used to remove selenium species from MIW, then selenium removal is achieved, but the final effluent contains selenium in reduced oxidation states which remain bioavailable and toxic to aquatic life
Solution Approach 1:
The patent changes the oxidation state parameter of selenium from reduced forms (+4, +2, -1, -2) to the oxidized selenate form (+6) through advanced oxidation processes. This parameter change transforms selenium into a less bioavailable form that is safer for aquatic environments while maintaining effective selenium removal.
Solution Approach 2:
The patent employs strong oxidants including ozone, hydrogen peroxide, and ultraviolet light in combination to accelerate the oxidation of reduced selenium species to selenate. This accelerated oxidation approach overcomes the limitations of biological treatment by rapidly converting toxic reduced selenium forms to less harmful selenate.
2Object-affected harmful factors
If chemical oxidants like potassium permanganate are used to oxidize reduced selenium species to selenate, then selenium bioavailability is reduced, but additional chemical treatment steps and residual oxidant removal are required
Solution Approach 1:
The patent merges multiple oxidation mechanisms (ozone oxidation, hydrogen peroxide oxidation, and UV photolysis) into a unified advanced oxidation process. This combination approach achieves effective selenium oxidation while allowing for integrated treatment where residual oxidants can be managed together, reducing overall process complexity compared to sequential chemical treatments.
Solution Approach 2:
The advanced oxidation process generates highly reactive hydroxyl radicals that spontaneously oxidize reduced selenium species without requiring additional chemical additives or complex control systems. The system essentially self-regulates the oxidation process through the inherent reactivity of the AOP-generated radicals.
3Quantity of substance
If adsorption media containing iron, aluminium, or titanium oxides are used to remove reduced selenium species, then selenium adsorption is achieved, but less than one percent of selenium is removed from the media by ozonated water
Solution Approach 1:
The patent applies preliminary advanced oxidation treatment to convert reduced selenium species to selenate before the selenium encounters adsorption media. This preliminary oxidation action prevents selenium from binding strongly to the adsorption media, ensuring that adsorbed selenium can be effectively removed by subsequent ozonated water treatment.
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 oxidizes reduced selenium species to selenate, significantly reducing their bioavailability in treated water, thereby improving the efficiency of selenium removal and ensuring the treated water is safer for aquatic environments.
Implementation Method 1
subjecting the MIW to an advanced oxidation process (AOP) including ultraviolet light and ozone or ozone and hydrogen peroxide to oxidize the one or more selenium species to selenate
Implementation Method 2
subjecting the MIW to an advanced oxidation process (AOP) including ultraviolet light and ozone or ozone and hydrogen peroxide
Data Source
AI summary
A process for treating mine impacted water containing one or more reduced selenium species by an advanced oxidation process (AOP) including ozone and ultraviolet light, or ozone and hydrogen peroxide is disclosed. The process oxidizes the one or more reduced selenium species to selenate and thereby produces AOP treated water. Residual oxidants are removed from the AOP treated water.