Slime-Controlling Agent for Activated Carbon and RO Membrane Biofouling
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Solution Overview
Problem
In electronic device factories, the treatment of organic-matter-containing water for ultrapure water production and drainage recycling faces challenges such as biofouling and flux reduction in RO membrane separation devices due to microorganism growth and organic matter attachment, which existing methods like hot water sterilization and chlorine-based disinfectants fail to address effectively, especially in activated carbon towers and RO membranes.
Innovation Solution
A method involving a slime-controlling agent composed of a combined chlorine agent produced from a chlorine-based oxidizer and a sulfamic acid compound is used, which is added to the water before activated carbon treatment and RO membrane separation, along with pH adjustment to 9.5 or higher to inhibit microorganism growth and prevent biofouling, while also using a scale inhibitor to prevent scale formation and maintain membrane durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chlorine-based disinfectants are used to sterilize activated carbon towers, then sterilization effect is improved, but the disinfectant is degraded at the surface of the lower layer of activated carbon tower and cannot prevail in the entire portion, resulting in insufficient sterilization
Solution Approach 1:
The patent uses air as an intermediary carrier to transport the chlorine-based disinfectant from the upper layer to the lower layer of the activated carbon tower. The air flow distributes the disinfectant throughout the entire tower, ensuring uniform sterilization effect without degradation at specific locations.
Solution Approach 2:
The patent applies preliminary action by introducing the chlorine-based disinfectant into the air stream before it contacts the activated carbon tower. This allows the disinfectant to be distributed throughout the tower via air flow, ensuring it reaches all portions including the lower layer where it would otherwise be degraded.
2Reliability
If hot water sterilization is used to sterilize activated carbon towers, then sterilization effect is improved, but high-temperature hot water must be flowed and maintained for a prolonged period, which is not industrially advantageous
Solution Approach 1:
The patent changes the parameters of sterilization by using chlorine-based disinfectants in the air stream instead of hot water. This allows sterilization to be achieved with lower temperature and shorter time, making the process more industrially advantageous while maintaining effective sterilization.
Solution Approach 2:
The patent replaces the mechanical hot water sterilization system with a chemical sterilization system using chlorine-based disinfectants carried by air flow. This substitution eliminates the need for high-temperature water circulation and prolonged heating time.
3Quantity of substance
If organic matter concentration in water flowing into activated carbon tower is high, then activated carbon treatment is effective for removing organic matter, but microorganisms flowing out from the tower cause biofouling of safety filter or RO membrane, resulting in clogging
Solution Approach 1:
The patent applies preliminary anti-action by introducing chlorine-based disinfectants into the air stream that passes through the activated carbon tower before the treated water flows to the RO membrane. This pre-sterilization prevents microorganisms from causing biofouling in subsequent processing stages, protecting the RO membrane from clogging.
Solution Approach 2:
The patent uses air as an intermediary to carry chlorine-based disinfectants through the activated carbon tower and into the treated water. This intermediary approach allows sterilization to occur without directly adding chemicals to the water stream, effectively preventing biofouling while maintaining organic matter removal efficiency.
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 inhibits microorganism proliferation and biofouling in activated carbon and RO membranes, maintains long-term stable treatment, and reduces TOC concentration, ensuring high-quality treated water without deteriorating the RO membranes, thus addressing the limitations of previous methods.
Implementation Method 1
a slime-controlling agent for activated carbon, the agent comprising a combined chlorine agent produced from a chlorine-based oxidizer and a sulfamic acid compound
Implementation Method 2
RO membrane separation treatment of a later step using, as raw water, industrial water or drainage drained from a factory
Implementation Method 3
The purposes of the activated carbon treatment are to remove an oxidizer in the raw water or to remove organic matter and chromaticity, etc.
Data Source
AI summary
Disclosed is a treatment apparatus capable of inhibiting growth of microorganisms and carrying out long-term stable treatment in an activated carbon tower and a reverse osmosis membrane separation device during processes including activated carbon treatment and RO membrane separation treatment of a later step in a system for manufacturing ultrapure water used in an electronic device factory. A method for treating organic-matter-containing water includes: the slime-controlling-agent-adding step of adding a slime-controlling agent to organic-matter-containing water; the activated-carbon-treating step of treating with activated carbon the organic-matter-containing water having undergone the slime-controlling-agent-adding step; and the reverse-osmosis-membrane-separation step of passing the organic-matter-containing water having undergone the activated-carbon-treating step through means for reverse osmosis membrane separation, wherein the slime-controlling agent uses a combined chlorine agent produced from a chlorine-based oxidizer and a sulfamic acid compound.