Reverse Osmosis Membrane Backflushing for Standby Quality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Reverse osmosis systems suffer from reduced membrane efficiency due to dirt and encrustations, leading to poor water quality during standby periods and short service life, with re-salinization of permeate and contamination issues due to diffusion and bacterial introduction during flushing.
Innovation Solution
A method and device that utilize a semipermeable membrane with a pressure vessel to backflush permeate through the membrane during idle states, displacing concentrate and deposits, maintaining low conductivity and preventing contamination, while using a pressure tank to accumulate and pressurize permeate for effective cleaning without external fluids, ensuring continuous water quality and extended membrane life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If reverse osmosis systems are operated in discontinuous mode, then energy consumption is reduced and system longevity is improved, but permeate quality deteriorates due to diffusion of contaminants from concentrate to permeate side during standby
Solution Approach 1:
The system performs preliminary action by flushing the membrane with permeate at the beginning of each extraction cycle after standby period. This preliminary flushing removes contaminants that have diffused to the permeate side during standby, ensuring high initial permeate quality before regular extraction begins
Solution Approach 2:
The system implements periodic action by automatically alternating between extraction operation and standby flushing cycles. During standby, permeate is periodically pushed through the membrane to clean the concentrate side, creating a rhythmic pattern of operation that maintains quality while reducing energy consumption compared to continuous operation
2Reliability
If reverse osmosis systems operate continuously, then permeate quality is maintained, but membrane service life is reduced due to accumulation of dirt and encrustations
Solution Approach 1:
The system uses periodic action by switching between extraction and standby flushing modes. During standby periods, the membrane is automatically flushed with permeate to remove accumulated dirt and encrustations, providing regular cleaning without requiring continuous high-flow operation that would shorten membrane life
Solution Approach 2:
The system implements self-service by using the produced permeate itself to clean the membrane surface during standby periods. The permeate, being pure water, automatically flushes away contaminants from the concentrate side of the membrane, allowing the system to clean itself without external cleaning agents or additional water sources
3Reliability
If permeate is flushed through wastewater conduit during standby, then membrane is cleaned, but bacterial contamination is introduced into the permeate system
Solution Approach 1:
The system applies inversion by reversing the normal flow direction during standby. Instead of flushing wastewater through the membrane as in conventional systems, pure permeate is pushed through the membrane from the permeate side to the concentrate side, cleaning the membrane while maintaining hygiene by using clean water rather than wastewater
4Reliability
If membrane retention rate is increased to reduce contaminant passage, then permeate purity is improved, but concentrate concentration increases leading to faster membrane fouling
Solution Approach 1:
The system maintains continuity of useful action by continuously cycling between extraction and standby flushing modes. This ensures that while high retention rate membranes are used for maximum purity, the membrane surface is continuously cleaned during standby periods, preventing fouling accumulation and extending service life despite the higher concentrate concentration
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 solution significantly reduces re-salinization and contamination of permeate, maintains low conductivity, and extends the service life of the semipermeable membrane by regularly removing deposits and contaminants, ensuring consistent water quality and improved system efficiency.
Implementation Method 1
purify drinking water using reverse osmosis (RO)... pressing it against the membrane under pressure... water molecules pass through the membrane and leave the first chamber, while the respective dissolved substances are held back by the membrane
Implementation Method 2
passing part of the permeate through the membrane due to an overpressure and thereby displacing the concentrate on the concentrate side of the membrane... using a pressure tank to accumulate and pressurize permeate for effective cleaning
Implementation Method 3
a concentration gradient between concentrate and permeate is established, which is generally greater than 20 μS/cm. As a result, the salts, heavy metals, and other contaminants, of which at least 98% are retained during operation, will still diffuse to the permeate side during standby
Data Source
AI summary
In order to improve the lifespan of the semi-permeable membrane or the yield of the reverse osmosis system in the treatment of drinking water by means of reverse osmosis, the invention provides a device for treating drinking water with at least one reverse osmosis vessel which is divided into at least two chambers by at least one semi-permeable membrane, wherein a first chamber has an inlet for the water to be treated and an outlet for the concentrate, and the second chamber has an outlet for the treated water, wherein the device comprises at least one pressure vessel which is connected to the outlet for the treated water via a line, wherein the device is designed in such a way that, in an idle state, treated water flows out of the pressure vessel, through the semi-permeable membrane and into the first chamber.