Related Experiment Video
Updated: May 28, 2026
09:39
Proof-of-Concept for Gas-Entrapping Membranes Derived from Water-Loving SiO2/Si/SiO2 Wafers for Green Desalination
Published on: March 1, 2020
Development of a Zero-Stagnant-Water Purification System Based on Smart Series-Parallel Control of Dual RO Membranes
Mei Ma1, Bin Huang2, Lingling Mei1
1School of Electric and Information Engineering, Yangzhou Polytechnic Institute, Yangzhou 225002, China.
Membranes
|May 26, 2026
Summary
This study introduces a novel dual-membrane reverse osmosis (RO) system that eliminates stagnant water during idle periods. This innovative design enhances water quality and reduces membrane fouling in intermittently operated RO systems.
Area of Science:
- Environmental Engineering
- Water Treatment Technologies
- Membrane Science
Background:
- Intermittently operated, tankless reverse osmosis (RO) systems face challenges with water stagnation during idle periods.
- Stagnation leads to degraded permeate quality, accelerated membrane fouling, and reduced system performance.
- Existing systems often suffer from performance loss and require frequent maintenance due to stagnant water issues.
Purpose of the Study:
- To develop and validate an engineering solution to eliminate stagnant water in intermittently operated RO systems.
- To maintain high permeate quality and reduce fouling in decentralized and point-of-use RO applications.
- To enhance the operational stability and efficiency of tankless RO systems.
Main Methods:
- A dual-membrane RO configuration with flexible series-parallel switching was designed.
- An adaptive control strategy was integrated to regulate membrane switching and flushing based on real-time feed-water quality.
- The system was evaluated under representative intermittent operating conditions, including long-term testing.
Main Results:
- The zero-stagnant-water strategy effectively prevented residual water accumulation during system shutdowns.
- Stable permeate quality was maintained, with total dissolved solids consistently below 10 mg/L.
- Reduced membrane fouling and slower performance degradation were observed compared to conventional systems, enhancing desalination efficiency.
Conclusions:
- The proposed dual-membrane RO system with adaptive control successfully eliminates stagnant water, improving water quality and system longevity.
- The modular design and simple control logic make the approach transferable to various decentralized and point-of-use membrane water treatment applications.
- This solution offers a reliable method for achieving high-quality water under intermittent operation, addressing a critical challenge in RO technology.
Related Concept Videos
01:30Biological Treatment of Effluent and Waste Water
Biological wastewater treatment relies on the metabolic activity of microorganisms to remove pollutants from sewage. In modern treatment systems, this process is organized into sequential stages that progressively reduce solid material, dissolved organic matter, and microbial contamination. Each stage plays a distinct role in improving water quality and preparing the effluent for safe discharge or reuse.Primary and Secondary TreatmentPrimary treatment is a physical process that removes large...
01:29Bioreactor Design and Operational System
Bioreactors are engineered vessels designed to cultivate microorganisms under controlled conditions for industrial bioprocessing. They maintain sterility and allow precise regulation of pH, temperature, oxygen, and nutrient levels to optimize microbial growth and metabolite production. Bioreactors range from small laboratory units of 1 liter to industrial systems holding up to 500,000 liters, though only about 75% of their volume is actively used for fermentation. The remaining headspace...
01:28Bioreactor Controls-I
Maintaining optimal conditions within fermenters is essential for maximizing microbial productivity and ensuring process efficiency. This lesson focuses on key parameters—temperature, foam, pH, carbon dioxide, oxygen, and pressure—and their precise measurement and control strategies in fermentation systems.Temperature ControlTemperature regulation is critical due to the exothermic nature of many fermentation processes. In small laboratory fermenters, temperature is commonly monitored using...
01:18Bioreactor Controls-II
In aerobic fermentations, oxygen is vital for microbial growth and metabolite production. Since air comprises only about 20% oxygen and the gas is poorly soluble in water—just 9 ppm at 20°C—supplying sufficient oxygen becomes a critical challenge, especially in high-demand processes like yeast growth or citric acid production. Even a fully saturated broth may offer only a few seconds of oxygen availability.To address this, sterile or scrubbed air is introduced into the fermentor via a sparger...