Nano filtration system

Types of Nano Filtration Systems

A nano filtration system is part of a membrane filtration family that sits between ultrafiltration and reverse osmosis. It removes materials with a high molecular weight, like organic compounds, divalent and higher ions, while allowing essential minerals and monovalent ions like sodium and chlorine to pass through. Here are the key types of nano-filtration systems:

• Cross-flow filtration:

  The prevalent flow pattern in NF membranes and the most commonly used configuration. In cross-flow filtration, the feed water stream is tangentially fed to the membrane surface. Therefore, part of the feed water flows along the membrane surface, and the retentate is partially recycled or discarded. The cross-flow filtration keeps sweeping the membrane surface and prevents the fouling of the membranes. This flow pattern effectively separates the permeate from the feed water, which is then used for subsequent treatment or disposal.

• Dead-end filtration:

  Only the feed water permeates the membrane while the retained particles accumulate on the membrane surface. Dead-end filtration is easy to assemble and run, making it popular in laboratory-scale experiments and smaller industrial applications. However, continuous particle accumulation on the membrane surface leads to fouling and requires frequent cleaning or replacing of membranes.

• Spiral-wound membranes:

  The most-used module design for nano filtration. The membrane leaves are placed in a spiral fashion, which provides a large membrane area in a compact module. This design improves the permeate flow rate and the rejection of undesirable substances, thereby enhancing treatment efficiency. The other advantage of spiral-wound membranes is that they reduce energy consumption during the filtration process.

• Cassettes:

  MKHK is an open cassette system. The NF membranes are made in a cartridge format and are fixed into a support cassette. The cassette system is suitable for small-scale applications such as laboratory water treatment or small industrial process water treatment. Therefore, it is easy to maintain and replace plastic cassettes with other types.

• D-tank:

  It is a dead-end filtration system in a dynamic flow. Feed water enters from beneath the membrane, and the permeate exits from the top. It has a high concentration retention zone, making it ideal for bio-matter removal and effluent treatment.

Specification and Maintenance

Several specifications are important to consider when buying a Nanofiltration system for commercial use. They ensure that the system is compatible with existing infrastructure, can perform the desired functions, and will be durable.

• Membrane Area

  This specification denotes the effective surface area of the nanofiltration membrane. The membrane surface area affects the water flow rate and the volume of water the system can treat in a specific time. For commercial buildings, a membrane area of 200m2 to 500m2 is ideal.

• Operating Pressure

  Operating pressure refers to the force that pushes water through the nanofiltration membrane. When water disposal, food and beverage production, or industrial processes are involved, the operating pressure must be above 30 bar (435 psi) for effective separation of contaminants to occur.

• Concentration Polarization

  It occurs when the solutes rejected by the nanofiltration membrane accumulate on its surface. This phenomenon can reduce the water flux of a nanofiltration system and increase membrane fouling. A commercial system with a design that minimizes concentration polarization will keep productivity high.

• Membrane Lifespan

  Nanofiltration membranes have finite lifespans and will eventually require replacement. The lifespan of membranes in commercial systems vary greatly. They may last between 5 to 15 years, depending on the materials, environmental conditions, and maintenance practices.

• Recovery Rate

  The recovery rate shows the percentage of feed water that is converted to permeate water by the nanofiltration system. Commercial systems have recovery rates between 85% and 95%.

It is crucial to maintain a nanofiltration system so that it functions well and lasts a long time. Some maintenance practices include cleaning the membranes periodically to remove any fouling, calibrating the system controls and pressure gauges frequently, and inspecting the system for any leaks that may occur. In addition, the filters and pump need to be replaced or serviced at the recommended intervals so that the nanofiltration system performs its job effectively.

Scenarios of using the nano filtration system

Nano filtration systems can provide many uses in industrial and commercial sectors because they can offer various water treatments. Some usage scenarios are as follows:

• Food and beverage industry: In the food and beverage industry, a nano filtration system can purify water and remove unwanted substances, flavoring, odor substances, and other impurities. It can help food and beverage manufacturers ensure that the water used in food processing and beverage production meets high-quality standards to maintain product taste and consumer health.
• Pharmaceutical industry: The pharmaceutical industry requires extremely high-quality water for drug production and equipment cleaning. A nano filtration system can provide pure water meeting pharmaceutical standards. It can remove minerals, bacteria, viruses, and other contaminants, ensuring that the water used is pure and uncontaminated.
• Hospitality industry: Hotels and hospitality industry can use a nano filtration system to provide clean and safe drinking water for guests. It can filter tap water or other sources of water to remove contaminants, thereby improving the quality and taste of drinking water.
• Desalination and water treatment plants: Nano-filtration technology plays a significant role in desalination plants and water treatment facilities. It helps to treat marine water and wastewater, removing salts, minerals, and organic matter. This enables the production of potable water from otherwise non-drinkable sources.
• Agriculture and irrigation: Nano filtration systems can also be used in agricultural irrigation systems. They can treat groundwater or surface water used for irrigation, removing pathogens and contaminants that could harm crops. This helps to ensure the safety and quality of agricultural products.
• Building and facilities management: In public places and facilities, such as schools, hospitals, and office buildings, nano filtration systems can be installed to provide clean and safe drinking water. They can replace bottled water or improve the quality of tap water, reducing the risks associated with water sources.
• Environmental protection: Nano filtration systems can be applied in environmental protection fields, such as industrial wastewater treatment or soil and groundwater remediation. They can assist in removing pollutants and contaminants, thereby recovering and reusing water resources.

How to choose a nano filtration system

Many factors need to be considered before buying a nano filtration system for commercial use.

• Quality of water:

  The characteristics of the water that needs to be filtered should be examined. Knowing the size of contaminants, bacteria, and chemicals will help select an NF system designed to handle specific pollutants.

• Flow rate and capacity:

  Determine the required flow rate and treatment capacity based on water consumption. Consider factors like peak demand, standby facilities, and system scalability to ensure the chosen NF system can meet future demands without compromising performance.

• NF membrane configuration:

  Evaluate the available membrane configurations, such as spiral-wound, tubular, or hollow fiber, and select one that suits the specific application requirements, space constraints, and maintenance considerations.

• Integrated pre-and post-treatment:

  Consider NF systems with integrated pre-treatment (e.g., sedimentation, coagulation) and post-treatment (e.g., disinfection, mineralization) components to optimize overall water treatment efficiency and reduce supplementary system.

• Energy efficiency:

  Consider energy-efficient nano filtration systems to reduce operational costs and environmental impacts.

• Regulatory compliance:

  Ensure the selected nano filtration system complies with relevant water quality standards and regulations to avoid potential legal risks and ensure public health protection.

• System integration:

  Consider the system integration capability of the nano filtration system, ensuring that it can be easily integrated into existing water treatment infrastructure and control systems, minimising disruption and facilitating cohesive operation.

• Life cycle cost analysis:

  Perform a comprehensive life cycle cost analysis of different nano filtration system options, considering factors such as initial investment, energy consumption, maintenance requirements, membrane replacement cost, and residual value to identify the most economically viable solution in the long run.

• Sample testing:

  Request samples or pilot-scale demonstrations of shortlisted nano filtration systems to evaluate their performance, reliability, and ease of operation in real-world conditions before making a final purchase decision.

FAQ

Q1: Are there any drawbacks to a Nano filtration system?

A1: The main drawback to a nanofiltration system is its cost. Nano filtration systems are more expensive than traditional water treatment systems. They also require regular maintenance. Cartridges need to be replaced, and any systems with complex circuitry need to be examined by professionals with training and expertise.

Q2: How long do nanofiltration membranes last?

A2: Nanofiltration membranes typically last between 5-10 years, depending on the care and maintenance they receive.

Q3: What is the difference between nano and ultra-filtration?

A3: While both nano and ultrafiltration use similar technology, they differ in their ability to separate contaminants. Nanofiltration is capable of removing divalent ions and small organic molecules, while ultrafiltration focuses on removing larger soluble substances and bacteria.

Q4: Can a nanofiltration system affect the taste of water?

A4: A nanofiltration system will improve the taste of water by removing the organic matter that causes bad tasting water.