Nanofiltration Water Softener Brine Recycling
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Solution Overview
Problem
Current water softening systems discharge significant amounts of brine solution containing hardness ions into the environment during regeneration, leading to pollution and corrosion, prompting restrictions on their use.
Innovation Solution
A water softening system incorporating nanofiltration technology to separate multivalent hardness ions from the brine solution, allowing for the recycling of the monovalent brine solution and reducing salt discharge during regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional water softening systems discharge brine solution containing hardness ions into the environment during regeneration, then the regeneration process can be completed, but environmental pollution and corrosion occur
Solution Approach 1:
The patent extracts the harmful multivalent hardness ions (calcium, magnesium) from the brine solution through nanofiltration, allowing the monovalent brine solution to be recycled while removing only the harmful components for discharge
Solution Approach 2:
The system recovers and reuses the monovalent brine solution containing sodium or potassium ions by directing it back to the resin bed for continued ion exchange operations, while discarding only the small portion containing multivalent hardness ions
2Reliability
If brine solution is discharged into sewers or septic systems during regeneration, then hardness ions are removed from water, but corrosion in sewage system and contamination of fresh water supplies occur
Solution Approach 1:
The nanofiltration membrane selectively extracts multivalent hardness ions from the brine solution based on their ionic charge and size, allowing the remaining monovalent brine solution to be safely discharged or recycled without causing corrosion or contamination
Solution Approach 2:
The system applies different handling to different components of the brine solution: multivalent hardness ions are removed and discharged, while monovalent brine solution is recycled, creating a localized quality separation that resolves the contradiction
3Object-generated harmful factors
If nanofiltration is used to separate hardness ions from brine solution, then brine can be recycled and pollution reduced, but device complexity increases
Solution Approach 1:
The nanofiltration membrane acts as an intermediary separation barrier that uses its selective permeability properties to separate ions based on charge and size, enabling brine recycling without requiring complex chemical treatment processes
Solution Approach 2:
The system replaces complex mechanical separation systems with a membrane-based nanofiltration process that uses physical properties of the membrane (pore size, charge) to achieve separation, simplifying the overall system design
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
The system recovers approximately 90% of the brine solution, minimizing environmental pollution and the cost of salt, while reducing the amount of salt discharged during regeneration.
Implementation Method 1
Nanofiltration (NF) is a pressure driven, membrane separation technology that separates ionic solute from water supplies based on the ionic charge of the solute
Implementation Method 2
separates ionic solute from water supplies based on the ionic charge of the solute
Implementation Method 3
Preferred embodiments of the present invention include a pump that supplies the force required to effect the separation and the feeding of a brine solution or feed stream into a housing containing a nanofilter membrane element
Implementation Method 4
Utilizing a sodium ion exchange process, resin-based water softeners are installed on water lines to soften most if not all of the water used inside such homes
Implementation Method 5
Through a chemical exchange process, the calcium and magnesium ions which were adsorbed onto the resin are stripped off and replaced with sodium or potassium ions
Implementation Method 6
As a water supply passes through ion exchange resins inside a water softener, the calcium and magnesium ions bond to the resins and are removed from the water flow
Data Source
AI summary
A water softening system includes apparatus and process that recycles a substantial percentage of the brine. This system conventionally includes a brine tank and a softening tank through which hard water from a source passes during normal operation. During the regeneration cycle, the brine solution in the brine tank passes through the softening tank acquiring hardness ions, and then through a nanofilter that passes a much higher proportion of the brine ions than the hardness ions. The hardness ions flow from the upstream end of the nanofilter into a drain. The liquid passing through the nanofilter contains salt that returns to the brine tank for reuse. A preferred embodiment includes a pump to force the brine solution through the nanofilter and a throttling valve connecting the upstream side of the nanofilter to a drain, and through which the hardness ions flow.