Reverse Osmosis Membrane Protection via Scale Inhibitor Timing
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Solution Overview
Problem
Reverse osmosis membranes in water treatment systems are prone to oxidative degradation due to low concentrations of oxidative substances that cannot be detected by conventional measurement methods, leading to potential membrane damage and reduced water quality, especially when biofilms form, making it difficult to maintain safe operation and prevent fouling.
Innovation Solution
A method is developed to determine the optimum addition timing for a scale inhibitor based on the concentration of oxidative substances and the inhibitor itself, ensuring sufficient reduction and neutralization, which involves adjusting the feed time of the inhibitor in the water treatment process to prevent oxidative degradation of the reverse osmosis membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement methods are used to detect oxidative substances, then measurement simplicity is maintained, but low concentrations of oxidative substances cannot be detected, leading to undetected membrane degradation
Solution Approach 1:
The patent introduces a scale inhibitor that also functions as a reducing agent as an intermediary substance. This mediator reacts with undetected oxidative substances to neutralize them before they can damage the membrane, effectively extending the detection capability beyond conventional measurement limits without complex instrumentation
Solution Approach 2:
The patent replaces the mechanical/physical measurement system with a chemical solution approach. Instead of using sophisticated sensors or instruments to detect low concentrations of oxidative substances, the system uses chemical reaction (reduction) to neutralize the harmful substances, substituting a chemical mechanism for a physical measurement mechanism
2Reliability
If oxidizing agents are added to prevent biofilm formation, then fouling prevention is improved, but oxidative degradation of the reverse osmosis membrane occurs
Solution Approach 1:
The patent converts the harmful effect of oxidizing agents (which cause membrane degradation) into a beneficial effect by using scale inhibitors with reducing properties. These substances neutralize the oxidizing agents, transforming the potential harm into a protective mechanism that preserves membrane integrity while maintaining fouling prevention
Solution Approach 2:
The scale inhibitor acts as an intermediary between the oxidizing agent and the membrane. It intercepts the oxidizing agent through reduction reactions, preventing direct contact between the harmful oxidant and the membrane, thus protecting the membrane while allowing the oxidizing agent to continue preventing biofilm formation
3Productivity
If feed time of scale inhibitor is insufficient, then production efficiency is maintained, but oxidative substances are not sufficiently reduced, leading to membrane degradation
Solution Approach 1:
The patent optimizes the feed time parameter of the scale inhibitor to achieve sufficient reduction of oxidative substances. By carefully controlling this temporal parameter, the system ensures adequate reaction time for neutralization while maintaining high production efficiency, resolving the contradiction between speed and effectiveness
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 allows for stable and cost-effective production of fresh water from saline sources by effectively reducing oxidative substances and preventing membrane degradation, maintaining membrane performance and extending its lifespan.
Implementation Method 1
a reverse osmosis membrane in a reverse osmosis membrane module to obtain permeate with a low salt concentration from raw water (water-to-be-treated) such as seawater
Implementation Method 2
water containing a solute such as salt is made to permeate a reverse osmosis membrane with pressure not lower than osmotic pressure
Implementation Method 3
determine the optimum addition timing for adding a scale inhibitor... so that the oxidative substances can be reduced and neutralized sufficiently
Data Source
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AI summary
The purpose of the present invention is to provide a water generating method for obtaining a low-concentration permeate by means of a reverse osmosis membrane module by using raw water such as sea water, as well as river water, groundwater, lake water, treated waste water, and so forth that contain salt, and to provide, in particular, a water treatment method and a water treatment apparatus for stably obtaining fresh water at low cost while preventing oxidative degradation of the reverse osmosis membrane module. Provided are: a water treatment method and a water treatment apparatus in which, in a reverse-osmosis-membrane treatment step for obtaining a low-concentration permeate by means of a reverse osmosis membrane module by using raw water such as sea water, as well as river water, groundwater, lake water, treated waste water, and so forth that contain salt, a scale inhibitor is added by determining the optimal adding timing in order to reductively neutralize oxidizing substances contained in water to be treated, which is supplied to the reverse osmosis membrane module.