Membrane Washing Control via Ammonia Monitoring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for chemical washing of separation membranes in water treatment, which use diluted sodium hypochlorite solutions, often fail to maintain sufficient cleaning effectiveness due to variations in water quality, leading to unstable transmembrane pressure differences and inadequate removal of deposits.
Innovation Solution
A method and apparatus that monitor the ammonic nitrogen concentration in membrane-treated water to adjust the dilution rate of the sodium hypochlorite solution, ensuring a consistent free chlorine concentration in the washing solution, thereby stabilizing the chemical washing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed dilution rate of sodium hypochlorite solution is used for chemical washing, then the washing process is simple to operate, but the chemical washing effect becomes insufficient when ammonic nitrogen is present in membrane-treated water
Solution Approach 1:
The patent implements dynamic adjustment of the dilution rate based on ammonic nitrogen concentration measurements. The system transitions from a fixed dilution rate to a variable dilution rate that automatically adapts to changing water quality conditions, ensuring reliable chemical washing效果 while maintaining ease of operation through automated control.
Solution Approach 2:
The patent introduces a feedback control mechanism where the ammonic nitrogen concentration in membrane-treated water is continuously monitored and used to adjust the dilution rate of sodium hypochlorite solution. This closed-loop feedback ensures that the chemical washing effect remains reliable regardless of variations in water quality.
2Loss of substance
If the dilution rate is increased to reduce sodium hypochlorite concentration, then operational costs decrease, but the chemical washing effect deteriorates when ammonic nitrogen reacts with free chlorine
Solution Approach 1:
The patent dynamically changes the concentration parameter of the washing solution based on ammonic nitrogen levels. When ammonic nitrogen concentration is high, the system reduces the dilution rate to maintain sufficient free chlorine concentration for effective washing. When ammonic nitrogen is low, the system can increase dilution to reduce chemical consumption, optimizing both cost and effectiveness.
3Reliability
If chemical washing is performed frequently to ensure sufficient cleaning, then deposit removal improves, but operational stability deteriorates due to varying water quality conditions
Solution Approach 1:
The patent performs preliminary measurement of ammonic nitrogen concentration before chemical washing to determine the appropriate dilution rate in advance. This preliminary action allows the system to prepare the correct washing solution concentration, ensuring effective deposit removal while maintaining operational stability by avoiding unnecessary frequent washing.
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 maintains a stable chemical washing effect by adjusting the sodium hypochlorite concentration based on ammonic nitrogen levels, preventing transmembrane pressure differences from rising and ensuring long-term stable membrane operation.
Implementation Method 1
when ammonic nitrogen and an organic nitrogen compound are contained in membrane-treated water, they react with free chlorine to produce chloramines such as NH2Cl, NHCl, NCl3 and the like
Data Source
AI summary
When a separation membrane (3) is washed with a chemical solution that is a sodium hypochlorite solution, which has a high concentration, diluted with membrane treated water stored in a chemical solution tank (6), an ammonic nitrogen concentration in membrane-treated water is monitored with a monitoring device (9), and a control device (8) controls a chemical solution dosing pump (7) using the concentration measured by the device (9) to adjust a dilution rate. Thereby, even when water quality of membrane-treated water varies, a sodium hypochlorite concentration in backwashing water can be retained constant, and fluctuation in the chemical washing effect can be prevented.