Reverse Osmosis Concentrate Treatment via Chemical Precipitation and Catalytic Oxidation
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Solution Overview
Problem
Current methods for treating reverse osmosis concentrated water are costly, environmentally harmful, and inefficient, particularly due to high salt content and high operating costs associated with evaporation and crystallization processes, which hinder widespread adoption of near-zero emission processes.
Innovation Solution
A method involving the addition of a precipitant and oxidant to reverse osmosis concentrated water, followed by catalytic oxidation and adsorption treatment, then subsequent reverse osmosis and oxidation steps, utilizing chlorine alkali industry waste water as a source of oxidants and precipitants to reduce COD and hardness, facilitating water recycling and near-zero discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If evaporation and crystallization processes are used to treat high salt concentrated water, then water recycling rate is improved, but investment and operating costs increase significantly
Solution Approach 1:
The patent changes the treatment approach from thermal evaporation to chemical precipitation followed by membrane filtration. By adjusting pH parameters and using chemical reagents to precipitate salts, the concentrated water is treated without requiring high-energy evaporation equipment, thereby reducing investment costs while maintaining water recycling rates
Solution Approach 2:
The patent replaces the mechanical/thermal evaporation system with a chemical-membrane treatment system. Instead of using evaporation equipment (multi-effect evaporators or MVR systems), the patent employs chemical precipitation agents followed by ultrafiltration and reverse osmosis membranes to separate and treat concentrated water, achieving similar water recovery without the high capital investment
2Productivity
If evaporation and crystallization processes are used to treat high salt concentrated water, then water recycling rate is improved, but operating costs increase significantly
Solution Approach 1:
The patent changes the energy-intensive evaporation process to a lower-energy chemical precipitation and membrane filtration process. By controlling pH and using chemical reagents to precipitate salts, followed by membrane separation, the system achieves water recycling at fraction of the energy cost of thermal evaporation
Solution Approach 2:
The patent substitutes the high-energy thermal evaporation system with a chemical-membrane system. The use of chemical precipitation agents to remove salts followed by ultrafiltration and reverse osmosis membranes enables water recovery without the substantial operating costs associated with multi-effect evaporation or MVR technologies
3Object-affected harmful factors
If conventional oxidation methods (ozone, hydrogen peroxide) are used to treat reverse osmosis concentrated water, then organic pollutants are degraded, but oxidant dosage and running cost increase
Solution Approach 1:
The patent introduces a catalyst as an intermediary substance that enables oxidation reactions to proceed more efficiently. The catalyst facilitates the degradation of organic pollutants by oxidants while being regenerated in the process, thereby reducing the total dosage of oxidants required compared to conventional direct oxidation methods
Solution Approach 2:
The patent employs catalytic oxidation to accelerate the oxidation of organic pollutants. By using catalysts to enhance the oxidative degradation process, the system achieves effective pollutant removal with reduced oxidant consumption compared to conventional non-catalytic oxidation methods using ozone or hydrogen peroxide
4Object-affected harmful factors
If Fenton oxidation process is used to treat reverse osmosis concentrated water, then organic pollutants are degraded, but pH adjustment and precipitation treatment are required increasing process complexity
Solution Approach 1:
The patent extracts the pH adjustment and precipitation steps from the Fenton oxidation process. By removing these complex auxiliary processes, the patent simplifies the treatment system while maintaining organic pollutant degradation effectiveness through alternative catalytic oxidation approaches that do not require acidic conditions or subsequent neutralization and solid-liquid separation
5Productivity
If electrodialysis or forward osmosis is used to concentrate reverse osmosis concentrated water, then water is recovered, but extremely high salt concentration requires evaporation treatment
Solution Approach 1:
The patent introduces chemical precipitation agents as intermediaries to remove salts from highly concentrated water. Instead of directly evaporating water with extremely high salt content, the patent uses chemical reagents to precipitate salts out of solution, followed by membrane filtration, thereby avoiding the need for evaporation equipment while achieving water recovery
Solution Approach 2:
The patent replaces the thermal evaporation system with a chemical-membrane treatment system for handling highly concentrated brine. By using chemical precipitation followed by ultrafiltration and reverse osmosis membranes, the system achieves water recovery from high-salt streams without requiring evaporation equipment, thereby eliminating the associated investment and operating costs
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 method effectively recycles water, reduces chemical costs, and meets environmental standards with improved water utilization rates and economic efficiency, utilizing waste materials to treat waste water, thus reducing environmental pressure and operational expenses.
Implementation Method 1
adding a precipitant and an oxidant to reverse osmosis concentrated water for treatment
Implementation Method 2
adding a precipitant and an oxidant to reverse osmosis concentrated water for treatment
Implementation Method 3
adding a catalyst for water treatment to the clear liquid for catalytic oxidation
Implementation Method 4
the liquid after catalytic oxidation is optionally subjected to an adsorption treatment
Implementation Method 5
conducting reverse osmosis treatment to the first-stage treated water
Data Source
AI summary
A method for treating reverse osmosis concentrated water, comprises adding precipitant and oxidant to reverse osmosis concentrated water for treatment, filtering to obtain clear liquid, and adding catalyst for water treatment to clear liquid for catalytic oxidation to obtain a first-stage treated water. Optionally, the liquid may be subjected after catalytic oxidation to an adsorption treatment; performing reverse osmosis treatment on first-stage treated water to obtain second-stage reverse osmosis product water and second-stage reverse osmosis concentrated water; and adding oxidant to second-stage reverse osmosis concentrated water for oxidation treatment to obtain directly discharged effluent water. The obtaining of effluent water may further comprise subjecting liquid after oxidation treatment to adsorption treatment. The above method can recycle 75-85 wt % of water, and operates easily. Thereby, improvement to overall utilization rate of water, and treatment of little remaining water is met to effluent standard for reduction of environmental pollution and economic investment.