What is a membrane in a RO plant?
Introduction to Reverse Osmosis Technology
Reverse Osmosis (RO) is a membrane-based separation technology that utilizes pressure as the driving force to remove dissolved solids, ions, and other impurities from water. By applying pressure greater than the osmotic pressure of the feed water, water molecules are forced through a semi-permeable membrane, while contaminants are rejected and concentrated in the brine stream. This process effectively reduces salinity, hardness, organic matter, and microorganisms, producing high-purity permeate water.
RO systems are widely used in seawater and brackish water desalination, industrial wastewater reuse, potable water purification, and various industrial processes requiring high-quality water. The performance and efficiency of RO depend on factors such as membrane material, feed water quality, operating pressure, and system design.
Under equilibrium conditions, the height difference between the two compartments corresponds to the osmotic pressure difference (typically denoted as π) of the solution at equilibrium concentration. Osmotic pressure is a function of the type and concentration of solutes in the solution. Generally, for every 100 ppm of total dissolved solids (TDS) concentration, the osmotic pressure π ranges from 0.04 to 0.075 bar.
π = nRT = MM RT
V
n = the amount of solute in molesR = the ideal gas constantT = temperature in KelvinV = the volume of the solutionMM = the molar mass of the solute
For example:A brackish water solution with a TDS of 1,500 ppm has an osmotic pressure of approximately 1.02 bar;A seawater solution with a TDS of 32,000 ppm has an osmotic pressure of approximately 21.8 bar.
Osmosis | Equilibrium | Reverse Osmosis
Natural OsmosisLow Solute Concentration → High Solute ConcentrationSemi-permeable Membrane
External Applied Pressure
Reverse Osmosis (RO) refers to the process where water flows in the opposite direction of natural osmosis—from a concentrated solution to a diluted one. This process must be driven by externally applied pressure. The reverse flow of water is hindered by three main factors: the osmotic pressure on both sides of the semi-permeable membrane, the internal resistance of the membrane itself, and the resistance caused by fouling on the membrane surface and within its pores during operation. Therefore, the pressure applied in reverse osmosis must significantly exceed the osmotic pressure difference of the solution.
For example:
In brackish water RO systems, the operating pressure is typically set at 15.5 bar (or higher), while the osmotic pressure difference of a 2,000 ppm brackish water solution is less than 2 bar.
For seawater with an osmotic pressure difference of approximately 22 bar (at 32,000 ppm), the applied operating pressure is usually around 55 bar.
1.2 Reverse Osmosis Membranes
The reverse osmosis system relies on reverse osmosis membranes (i.e., the semi-permeable membranes mentioned above) to achieve separation between solvents and solutes. These membranes allow the passage of solvents while rejecting other solutes. Currently, most reverse osmosis membranes feature a multi-layer composite polymer structure with polyamide as the separation layer. These membranes deliver excellent separation performance and long-term durability under conventional feed water conditions.
1.3 Key Performance Parameters
1. Recovery RateThe recovery rate refers to the percentage of feed water that is converted into permeate water. For example, a recovery rate of 75% means that for every 100 m³/d of feed water, the permeate water output is 75 m³/d.
For a single industrial reverse osmosis membrane element, the recovery rate in product performance testing typically ranges from 8% to 15%. For a full-scale reverse osmosis water treatment system, the recovery rate varies between 40% and 90%, depending on factors such as feed water characteristics (e.g., salt concentration, contaminants), system configuration, and operational conditions.
2. Rejection RateThe rejection rate defines the percentage of a specific solute retained by the reverse osmosis membrane after filtration relative to its concentration in the feed water.
Valence of Solutes: Solutes with higher valence exhibit higher rejection rates. For example, Ca²⁺ has a higher rejection rate than Na⁺.
Degree of Hydration: Ions with larger hydrated sizes achieve higher rejection rates. For instance, chloride ions (Cl⁻) are rejected more effectively than nitrate ions (NO³⁻).
Molecular Weight: Generally, solutes with higher molecular weights are rejected more efficiently than those with lower molecular weights.
Polarity of Solutes: Non-polar solutes typically show lower rejection rates. For example, benzene, despite its relatively high molecular weight, has a rejection rate of only about 25% due to its non-polar structure.
State of Solutes: Gaseous solutes are not rejected by reverse osmosis membranes. For instance, ammonia gas (NH₃) is not rejected, while ammonium ions (NH₄⁺) in low-pH solutions can be effectively retained.
Degree of Branching: Highly branched molecules exhibit higher rejection rates. For example, isopropanol has a higher rejection rate than n-propanol.
Other Factors: Additional influences include feed water conditions (e.g., pH, ionic strength, hardness) and membrane properties (e.g., surface charge characterized by zeta potential, hydrophilicity, and surface morphology).
The rejection performance of practical reverse osmosis membranes, especially nanofiltration membranes, depends on a combination of the above factors rather than any single variable. For more accurate data, product manuals and lab-scale simulation tests provide only preliminary reference information. We recommend users conduct pilot tests under actual field conditions to validate performance.
Is Your Wastewater Treatment Partner Meeting These 5 Critical Service Standards? Shanghai DUBHE Sets the Benchmark!
Is Your Wastewater Treatment Partner Meeting These 5 Critical Service Standards? Shanghai DUBHE Sets the Benchmark!
In today's demanding global market, choosing the right wastewater treatment technology partner is crucial. But how can businesses in Russia, the Philippines, Indonesia, Malaysia, and beyond ensure their provider delivers not just equipment, but true partnership and peace of mind? Shanghai DUBHE Environmental Protection Technology Co., Ltd., a leading innovator in comprehensive wastewater solutions, challenges the industry standard by asking: Are you receiving these essential services?
1. Does Your Provider Offer Lightning-Fast Pre-Sales Support & Solutions?Time is money, especially in fast-paced markets like Indonesia and the Philippines. DUBHE eliminates lengthy delays with its "DUBHE's Best Service" commitment, featuring 12-hour quick pre-sales response and free consulting. Whether you're a distributor in Russia or an end-user in Malaysia, DUBHE provides progressing solution design and technical support before you commit, ensuring the chosen aeration systems (like U.S. SSL), blowers, sludge dewatering equipment, or bio-filters perfectly fit your needs.
2. Are You Confident in Uncompromising Equipment Quality?Investing in wastewater treatment technology demands reliability. DUBHE, operating from its advanced Wuxi Yixing plant, implements strict quality control using cutting-edge testing equipment. This rigorous system guarantees the durability and performance of every solid-liquid separator, membrane module, and component shipped to clients worldwide, safeguarding operations from Russia to Southeast Asia.
3. Can You Get Critical Equipment Within Days, Not Weeks?Project timelines can't wait. Understanding the urgency in markets like the Philippines and Malaysia, DUBHE maintains significant stock and mass production capabilities. For standard items, quick delivery within 1-7 days is a reality. Even for specialized machinery, DUBHE prioritizes orders, ensuring minimal downtime for customers across its key regions, including Indonesia.
4. Is True 24/7 After-Sales Support Just a Promise or a Reality?Breakdowns don't respect business hours. DUBHE backs its products with 24-hour after-sales service. This includes guaranteed 24-hour technical support response, provision of necessary spare parts, free warranty repairs, and reasonable post-warranty maintenance. From troubleshooting in Russia to remote diagnostics in Indonesia, DUBHE's team is always ready.
5. Does Your Partner Invest in Your Long-Term Success?DUBHE goes beyond just selling equipment. They offer free technical training to ensure customers and distributors can operate systems efficiently. Their commitment includes monthly follow-ups during the warranty period, lifelong software upgrades for control systems, and on-site installation guidance. This holistic approach builds lasting partnerships, empowering clients across the Philippines, Malaysia, Russia, and Indonesia to manage their wastewater effectively for years to come.
Shanghai DUBHE: Committed to Your Success & Cleaner Water"At DUBHE, our core philosophy is serving our customers by exceeding expectations," states the company leadership. "We continuously innovate our aeration devices, sludge dewatering systems, and bio-filters, but we believe exceptional technology must be paired with unmatched service. We ask these questions because we live the answers, ensuring our partners in Russia, the Philippines, Indonesia, Malaysia, and globally have a reliable, responsive, and truly supportive wastewater treatment partner."
what is the new type of biological carriers
What Is the New Type of Biological Carriers? Discover the Revolutionary PCG Biocarrier for Superior Wastewater Treatment
Introduction: The Future of Wastewater Treatment is Here
In the evolving world of wastewater treatment, biological carriers play a critical role in biofilm processes, determining efficiency, cost-effectiveness, and environmental sustainability. Traditional carriers, such as plastic media or ceramic rings, often struggle with limitations like poor microbial adhesion, low surface area, and short lifespans. Enter PCG Biocarriers (Polymer Composite Gel Biocarriers) – a groundbreaking innovation by shanghai dubhe environmental protection&technology Co., Ltd., designed to revolutionize wastewater treatment with unmatched performance.
This article explores why PCG Biocarriers are the next-generation solution for industries, municipalities, and environmental projects seeking higher efficiency, lower sludge production, and longer-lasting performance.
Why PCG Biocarriers? The Science Behind the Innovation
1. Superior Material & Design
PCG Biocarriers are engineered from a highly hydrophilic polymer composite gel, inspired by Japanese technology and refined over a decade of R&D. Key features include:
Micron-level pore structure (≥10,000 m²/m³ surface area) – Maximizes microbial attachment.
98% porosity – Ensures optimal oxygen and nutrient diffusion.
Soft, non-abrasive texture – Protects equipment while resisting wear.
Unlike conventional carriers, PCG’s unique gel matrix naturally attracts beneficial bacteria, accelerating biofilm formation in just 3-7 days – 50% faster than traditional media.
2. Unmatched Performance in Wastewater Treatment
PCG Biocarriers excel in ammonia nitrogen (NH3-N), total nitrogen (TN), and COD removal, making them ideal for:
Municipal wastewater plants (meeting strict Class IV standards, e.g., TN
Bubble diffuser new technology application prospects
A bubble diffuser is a device widely used in industry and scientific research to introduce gases into liquids and generate bubbles for the purpose of stirring, mixing, and reacting. Recently, a new type of bubble diffuser has attracted extensive attention in the market, which has a series of advantages and features and shows unique application potential in certain fields.
First, the bubble diffuser is designed with innovative structures and materials. Compared with traditional bubble diffusers, the unit is more compact, lighter and easier to move and operate. It is also made of special materials that are corrosion- and temperature-resistant, enabling it to operate stably in a variety of harsh environments, thus meeting the needs of different industries and fields.
Application:
WATER TREATMENT: Bubble diffusers are used in the water treatment process to inject air or oxygen into the water to increase the oxygen content. This helps to improve the conditions for the growth of organisms in the water, such as in pond farming, aquariums, and sewage treatment.
Wastewater treatment: In the wastewater treatment process, bubble diffusers help to accelerate the decomposition of organic substances by bacteria, thus purifying the water.
Medical field: In medical equipment, bubble diffusers can be used in various treatments, such as oxygen therapy, respiratory therapy, etc., to provide patients with extra oxygen.
Biotechnology and laboratories: In laboratories, bubble diffusers are often used to stir and mix samples to facilitate biological or chemical reactions.
The birth of Polymer Composite Gel-new technology of bio-filler
To solve:
1. the carrier is mainly applied to contact oxidation method, the traditional carrier has poor hydrophilicity and low oxygen dissolution efficiency;
2. the small specific surface area of traditional carriers, the attachment amount of microorganisms is small, and the treatment capacity is poor;
3. Reducing sludge discharge and environmental pollution;
4. Traditional MBBR carrier hanging wear equipment corrosion layer, reducing the mission life of sewage treatment equipment; the use of wear debris resulting in damage to pumps & fans.
PCG-A new technology of bio-filler works better than MBBR.
PCG is a kind of water treatment bio-carrier product based on polymer hydrophilic material, which is inspired by the design of Japan, and referred to the application experience of Japan for about 20 years. Our R&D team has been working on the soft bio-carrier since 2010.
In 2010, our R&D team started to develop the soft bio-carrier, and after 6 years of design and development, we finally selected PCG as the soft bio-carrier with high hydrophilicity and biophilicity.
After 6 years of design and development, we finally chose a new high molecular weight material with high hydrophilicity, biophilicity, anti-abrasion, aeration and strong specific surface area as the substrate of the biocarrier, which was launched in 2016.
After 5 years of small and medium After 5 years of small and medium-sized trials, it will finally be put into large-scale production in 2020. As a biocarrier, PCG is ahead of similar products in China. And our technology now is the newest one about the six generation.
Advantages over traditional technology:
Excellent mechanical strength (wear resistance)；
Synergistic effect, incorporating biogel technology, to promote the growth and biological activity of immobilized advantageous bacterial flora；
Enhanced nitrification reaction；
Highly efficient adsorption capacity；
Simultaneous removal of specific organics (e.g. toxic aromatic compounds);
Hydrophilicity vs. hydrophobicity, oil-absorbing vs. non-oil-absorbing test comparing MBBR and ordinary sponge.
Application: Wastewater treatment:
Medical field:
Biotechnology and laboratories:
Beverage and food processing:
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