Ultrafiltration Equipment: Analysis of Principles, Specifications, and Core Advantages in Industrial Applications

 I. What is Ultrafiltration Equipment? What Are Its Core Differences from Other Membrane Filtration Technologies?  

In the field of water treatment technology, ultrafiltration equipment is a separation device that uses pressure as the driving force to intercept colloids, suspended solids, bacteria, and macromolecular organic matter in water through ultrafiltration (UF) membranes with pore sizes of 0.01-0.1 microns. Its core principle is the "sieving effect"—micropores on the membrane surface only allow water molecules and small molecules to pass through while blocking particles larger than the membrane pores, thereby purifying water quality (Baidu Encyclopedia entry for "ultrafiltration technology", 2024).  

 

Compared with other membrane filtration technologies, the uniqueness of ultrafiltration equipment lies in three aspects:  

1. Moderate Filtration Precision: It is between microfiltration (0.1-10 microns) and nanofiltration (0.001-0.01 microns). It can effectively remove bacteria (0.2-2 microns in diameter) and colloids (0.001-1 micron) without requiring excessively high operating pressure (usually 0.1-0.3MPa). Its energy consumption is only 1/5-1/3 of reverse osmosis (RO) ( Handbook of Membrane Separation Technology , 360 Library, 2023).  

2. Retention of Beneficial Substances: Unlike RO equipment, which removes minerals from water, ultrafiltration can retain beneficial ions such as calcium and magnesium, making it suitable for scenarios like drinking water purification ( Comparison of Drinking Water Treatment Technologies , academic paper, 2024).  

3. Stronger Anti-Fouling Performance: Ultrafiltration membranes mostly adopt hollow fiber or spiral wound structures, with larger membrane area and higher porosity (60-80%) than RO membranes. They are less prone to clogging and have longer cleaning cycles (usually 1-3 months, compared to 1-2 weeks for RO) (Wikipedia entry for "Ultrafiltration", 2024).  

 

For example, a comparative experiment at a municipal water plant showed that when treating the same batch of surface water, the effluent turbidity of ultrafiltration equipment remained below 0.1 NTU without the need for flocculants; while the effluent turbidity of the traditional sand filtration + activated carbon process fluctuated significantly (0.1-0.5 NTU) and required continuous chemical dosing ( Municipal Water Treatment Case Collection , 2023).  

 

 

 II. Core Components and Working Process of Ultrafiltration Equipment: A Complete Analysis from Inlet Water to Product Water  

 2.1 Key Components and Their Functions  

A complete ultrafiltration equipment consists of five core parts, with each component working together to ensure filtration efficiency:  

- Pretreatment System: Includes grilles (to remove large particles), security filters (5-micron precision to protect ultrafiltration membranes). In some scenarios, chlorination or ultraviolet disinfection is required (to inhibit microbial growth).  

- Ultrafiltration Membrane Modules: Classified by material into PVDF (polyvinylidene fluoride, strong anti-fouling), PES (polyethersulfone, good acid and alkali resistance), and PAN (polyacrylonitrile, low cost). PVDF membranes account for over 70% of industrial applications ( Guide to Ultrafiltration Membrane Materials , 2024).  

- Pressurization Device: Centrifugal pumps provide operating pressure of 0.1-0.3MPa to push raw water through the membrane modules.  

- Cleaning System: Includes a backwash pump (using product water to reverse flush the membrane surface) and a chemical cleaning tank (storing citric acid, NaOH, etc., for removing membrane fouling).  

- Control System: PLC automatically controls valve switching and cleaning cycles, and can monitor parameters such as water production, transmembrane pressure (TMP) in real time ( Automation Design of Ultrafiltration Equipment , 2023).  

 

 2.2 Typical Working Process  

The operation of ultrafiltration equipment includes three stages, forming a closed-loop operation:  

1. Filtration Stage: Raw water enters the membrane module under pressure. Water molecules and small molecules pass through the membrane pores to become product water, while impurities are intercepted on the membrane surface or in the membrane pores. A small amount of concentrated water (containing high-concentration impurities) is discharged (accounting for 5-10% of inlet water).  

2. Backwash Stage: Every 30-60 minutes of operation, the backwash program is activated—product water flows backward from the outlet of the membrane module to flush away loose contaminants on the surface. Backwash time is usually 1-2 minutes.  

3. Chemical Cleaning Stage: When the transmembrane pressure (TMP) exceeds 0.1MPa, 0.5-1% citric acid (to remove inorganic scale) or 0.1-0.5% NaOH (to remove organic matter) is used for cyclic cleaning for 30-60 minutes to restore membrane flux ( Operation Manual for Ultrafiltration Equipment , 360 Library, 2024).  

 

 

 III. Specifications and Selection of Ultrafiltration Equipment: How to Match the Needs of Different Scenarios?  

 3.1 Common Specifications and Applicable Scenarios  

The specifications of ultrafiltration equipment need to be comprehensively selected based on treatment capacity, water quality, and application scenarios. Core parameters include:  

Specification Indicator	Small Equipment (Household/Laboratory)	Medium Equipment (Industrial/Commercial)	Large Equipment (Municipal/Power Plant)
Water Production	0.1-1m³/h	1-50m³/h	50-1000m³/h
Number of Membrane Modules	1-2	4-20 (parallel)	50-200 (multiple groups in parallel)
Membrane Material	PAN/PES	PVDF/PES	PVDF
Operating Pressure	0.1-0.2MPa	0.15-0.25MPa	0.2-0.3MPa
Floor Area	0.5-2㎡	5-50㎡	100-500㎡

 

(Source: Ultrafiltration Equipment Selection Manual , 2024)  

 

 3.2 Three Principles for Selection: Matching on Demand to Avoid Resource Waste  

1. Water Quality Adaptation Principle:  

   - For high-turbidity water (e.g., river water, wastewater), prioritize PVDF membrane (strong anti-fouling) and add pretreatment (e.g., flocculation precipitation);  

   - For low-turbidity water (e.g., groundwater), PES membrane can be used to reduce costs.  

2. Capacity Redundancy Principle: Select equipment according to "peak water production × 1.2". For example, if a food factory has a peak water demand of 8m³/h, a 10m³/h equipment should be chosen to avoid supply shortages.  

3. Cost Principle: Compare the service life of membranes of different materials (PVDF membranes last 3-5 years, PAN membranes 1-2 years). Although PVDF has a higher initial investment, its annual average cost is lower ( Life Cycle Cost Analysis of Ultrafiltration Equipment , 2023).  

 

Case Study: A beverage factory needed to treat groundwater (turbidity 0.5NTU, total bacterial count 1000CFU/mL). A 10m³/h PVDF ultrafiltration equipment was selected. The total bacterial count in the product water was ≤10CFU/mL, meeting production needs, and the annual membrane replacement cost was 40% lower than that of PAN membranes (2024 factory procurement report).  

 

 

 IV. Industrial Applications of Ultrafiltration Equipment: Diverse Scenarios from Municipal Water Supply to Industrial Pretreatment  

 4.1 Municipal Drinking Water Purification: An Efficient Solution to Ensure Water Quality Safety  

In the field of municipal water supply, ultrafiltration equipment is gradually replacing traditional processes and becoming the mainstream technology:  

- Removal of Microorganisms: It can 100% intercept pathogenic bacteria such as Escherichia coli and Giardia. The product water can meet standards without disinfection ( Sanitary Standards for Drinking Water GB 5749-2022 requires total colony count ≤100CFU/mL);  

- Response to Sudden Pollution: When the turbidity of raw water suddenly increases (e.g., after heavy rain), the interception capacity of ultrafiltration membranes can quickly control turbidity below 0.1NTU, avoiding water plant shutdowns ( Emergency Water Treatment Technical Guide , 2024).  

 

Case Study: A municipal water plant in southern China adopted the "coagulation + ultrafiltration" process. The treated water turbidity stabilized at 0.05NTU, user complaints decreased by 60%, and disinfectant dosage was reduced by 80% ( Municipal Water Supply Reconstruction Case , 2023).  

 

 4.2 Industrial Wastewater Reuse: An Environmentally Friendly Choice to Reduce Production Costs  

Industrial wastewater can be reused after treatment by ultrafiltration equipment , realizing "turning waste into treasure":  

- Printing and Dyeing Wastewater: Ultrafiltration can remove dye molecules (molecular weight 1000-10000Da) and suspended solids from wastewater, which can be reused in the rinsing process. A printing and dyeing factory saved 300,000 tons of water annually and reduced sewage discharge fees by 1.5 million yuan after using it ( Industrial Wastewater Reuse Technology , academic paper, 2024);  

- Food Processing Wastewater: For example, dairy wastewater contains a large amount of protein (molecular weight 5000-100000Da). Ultrafiltration can intercept and recover it, reducing COD (Chemical Oxygen Demand) while creating economic benefits (a dairy company recovered protein powder worth 2 million yuan annually, 2023 data).  

 

 4.3 Reverse Osmosis Pretreatment: The "First Line of Defense" to Protect RO Membranes  

Installing ultrafiltration equipment before the RO system can significantly extend the life of RO membranes:  

- It removes colloids, suspended solids, and microorganisms, reducing SDI (Silt Density Index) from 5 to below 1 (RO membranes require SDI ≤5);  

- After an ultrafiltration pretreatment was added to the RO system of a power plant, the cleaning cycle of RO membranes was extended from 1 month to 3 months, and the service life was extended from 2 years to 3 years ( Pretreatment Technology for Reverse Osmosis Systems , Baidu Encyclopedia, 2024).  

 

 

 V. Maintenance and Cleaning of Ultrafiltration Equipment: A Practical Guide to Extend Membrane Life  

 5.1 Daily Maintenance Points  

- Parameter Monitoring: Record daily water production, transmembrane pressure (TMP), and product water turbidity. Cleaning is required when TMP exceeds 0.1MPa or water production drops by 15%;  

- Backwash Optimization: Adjust the backwash frequency (e.g., shorten to 30 minutes/time when microorganisms are active in summer). Control the backwash water pressure at 0.15-0.2MPa to avoid damaging membrane fibers;  

- Pretreatment Inspection: Check the security filter element weekly and replace it in time when clogged or damaged (usually every 3-6 months).  

 

 5.2 Chemical Cleaning Solutions: Precise Treatment for Different Pollution Types  

Pollution Type	Characteristics	Cleaning Agent and Operation
Inorganic Scale (Calcium, Magnesium)	Increased TMP, decreased water production	1-2% citric acid solution, cyclic cleaning at 40℃ for 60 minutes
Organic Pollution	Slimy membrane surface, increased COD	0.5-1% NaOH solution, cyclic cleaning at 30℃ for 90 minutes
Microbial Pollution	Odor in product water, excessive bacterial count	Soak in 500-1000ppm sodium hypochlorite solution for 2 hours

Case Study: Due to insufficient pretreatment, microorganisms grew on the membrane surface of an electronics factory’s ultrafiltration equipment , resulting in excessive bacterial count in the product water. After cleaning with 1000ppm sodium hypochlorite, the bacterial count returned to the qualified level, and TMP dropped from 0.12MPa to 0.08MPa (2024 equipment maintenance log).  

 

 VI. Technical Trends of Ultrafiltration Equipment: Development Direction of Intelligence and Greenization  

 6.1 Intelligent Upgrades  

- Online Monitoring System: Equipped with turbidity meters, TOC analyzers, and pressure sensors to transmit data to the central control room in real time and automatically alarm in case of abnormalities;  

- AI-Optimized Cleaning: Machine learning algorithms predict pollution trends and automatically adjust backwash and chemical cleaning cycles. A municipal water plant reduced water consumption by 10% after application ( Development Report of Intelligent Water Treatment Equipment , 2024).  

 

 6.2 Green Innovation  

- Low-Energy Membrane Modules: New hollow fiber membranes with 30% lower water resistance, reducing energy consumption to 0.05kWh/m³;  

- Degradable Membrane Materials: Ultrafiltration membranes based on natural polymers (e.g., chitosan) are developed, which can be naturally degraded after disposal, reducing solid waste pollution ( Research Progress of Green Membrane Materials , academic paper, 2023).  

 

 VII. Conclusion: Core Value and Future Outlook of Ultrafiltration Equipment in Water Treatment  

Ultrafiltration equipment has become a key technology in the water treatment field due to its "high efficiency, energy saving, and environmental protection" characteristics. It can meet the safety needs of municipal water supply, adapt to the reuse scenarios of industrial wastewater, and serve as a reliable guarantee for RO pretreatment, with its application scope continuing to expand.  

 

During selection, water quality, capacity, and cost should be considered, and PVDF membranes with strong anti-fouling properties are preferred. In daily maintenance, scientific cleaning and parameter monitoring are key to extending membrane life. In the future, with the development of intelligence and green materials, ultrafiltration equipment will make breakthroughs in energy consumption, automation, and sustainability, providing better solutions to global water scarcity ( White Paper on Ultrafiltration Technology Development , 2024).  

 

Whether improving drinking water quality or promoting industrial water recycling, ultrafiltration equipment is redefining the efficiency and standards of modern water treatment with its unique technical advantages.