Ultrafiltration: common industrial applications and uses
The ultrafiltration market is growing rapidly—and for good reason. With a list of benefits including energy efficiency, consistent water quality, high recovery rates, a small footprint, and little to no chemical use, it’s no wonder that the use of ultrafiltration is growing across all industrial sectors. Here, we’ll take a look at the importance of UF technology within key industries, and explore how and why ultrafiltration is used for process separation and wastewater treatment.
What contaminants does ultrafiltration remove?
Like all forms of membrane filtration, ultrafiltration works by excluding materials based on particle size. In fact, each type of membrane filtration is classed based on membrane pore size, which, arranged in order from coarsest to finest filtration, include: microfiltration (0.1 to 10 μm), ultrafiltration (0.001 to 0.1 μm), nanofiltration (0.001 to 0.01 μm), and reverse osmosis (0.0001 – 0.001 μm). With its pore size averaging around 0.01 μm, UF is effective for removal of suspended solids and pathogens, including:
As we’ve said, UF separation capabilities are limited based on particle size, so while it performs well for removal of the above materials, UF is unable to reliably remove the smallest particles. Materials like monovalent or multivalent ions, organic molecules, minerals, or salts would typically require nanofiltration or reverse osmosis, either in place of or in addition to UF. Although Nano and RO will filter, they are used primarily for dissolved ions in the fluid.
Technically speaking, UF can also be used for separation of larger materials that are also removable by means of microfiltration or media filtration, such as algae, protozoa, sand, clay, or complex metals. However, when dealing with streams that have a mix of differently-sized particles, it is often best to use coarser types of media or membrane filtration ahead of more delicate filtration. Doing so can help to prevent excessive cleaning needs, and prolong the life of costly downstream equipment by preventing blockages and fouling. That’s why you’ll often see microfiltration used for pretreatment ahead of ultrafiltration, or ultrafiltration used for pretreatment ahead of reverse osmosis.
How is ultrafiltration used in industry?
Ultrafiltration can be a great solution for many separation needs, as it offers benefits including low operation pressure and energy consumption, high feed stream recovery rates, and relatively simple maintenance, along with versatility for a wide range of contaminants and process conditions. In the most general terms, the main uses of UF systems include:
- Replacement of secondary and tertiary steps on conventional wastewater treatment trains
(i.e. coagulation, flocculation, sedimentation, sand filtration, chlorination)
- Treating wastewater for discharge or reuse
- Treating raw water for reduction of silt density index (SDI) or large MW natural organic matter (NOM)
- Purification or concentration of industrial process streams
- Pretreating streams for downstream reverse osmosis (RO) or ion exchange (IX)
These broadly describe how and why UF is used at industrial facilities, but it’s also worth noting that UF also serves a number of specialized process separation and water purification applications. Below, we’ve offered some examples of UF applications that are specific to various industries.
Power plants require large volumes of high purity water for boiler makeup and cooling tower feedwater applications. Over the past couple of decades, power generation facilities have increasingly looked to ultrafiltration for suspended solids removal, especially as a means of pretreatment ahead of reverse osmosis. This is because UF offers a small footprint and better energy efficiency compared to other separation methods, like distillation or conventional treatment trains. By producing a filtrate of reasonably high quality, UF can also improve the economics of RO by reducing fouling and extending the life of downstream RO membranes.
Refineries use water in a number of ways, including as process water, boiler feedwater, cooling water, and utility water. UF can be used to remove suspended solids, oil, grease, turbidity, and color to prepare feed streams for any of the above uses. When a stream is destined for more sensitive processes, such as in boilers, UF is often followed by other processes, like RO or IX. Refinery facilities often use UF pretreatment steps to reduce colloidal fouling in downstream equipment, which can help to reduce maintenance costs substantially.
Petrochemical & chemical
The petrochemical and chemical industries rely on ultrafiltration for RO pretreatment, as well as an extremely wide variety of specialized separation applications, and water reuse applications. Many of these entail the use of UF to remove suspended solids from wastewater or process streams prior to further separation with nanofiltration. This approach is used for purification of dyes, pigments, and optical brighteners, as well as recycling of acid and caustic streams. UF is also used for removal and concentration of metals, titanium dioxide, and calcium carbonate, among other materials.
Oil & gas
While the use of ultrafiltration within the oil and gas industry is somewhat more limited than in other sectors, it does have its place. Among the most common applications are the use of ultrafiltration for potable water generation on offshore rigs or in areas with limited access to water. Thanks to its ability to separate oil and water, UF is also useful for treatment of produced water resulting from bituminous sand extraction or hydraulic fracturing operations, and for recycling waste streams. Ultrafiltration has also been adopted for biofuel production, lending greater efficiency to ethanol isolation, which has traditionally been accomplished through energy-intensive distillation processes.
Mining & metals
The mining industry uses ultrafiltration for a number of applications, especially for recovery or reuse of liquid wastewater or process streams, or recovery and concentration of valuable solid materials. Specifically, this can include recovery of metals from wastewater or process streams, acid recovery from metal pickling solutions, and pretreatment of seawater prior to RO. UF is also used to treat mining wastewater for reuse or safe discharge, including acid mine drainage and tailing streams, and coal mining wastewater.
Food & beverage
The food and beverage industry uses ultrafiltration extensively for specialized separation applications. Its use is so varied and diverse, in fact, that it’s helpful to take a closer look at common ultrafiltration applications within some key food and beverage subsectors:
- Dairy: Ultrafiltration membranes exclude large macromolecules, like protein and fat, making UF an invaluable tool within the dairy industry, both for clarification of process streams, and for concentration and recovery of solids. Examples of common UF applications within the dairy industry include concentration of whey protein, casein or enzymes, protein standardization, lactose reduction, and brine clarification.
- Beverage: The primary use of UF within the beverage industry is for clarification and concentration of juice, beer, wine, coffee, tea, and other products, but UF is also used extensively for removal of microbes and proteins following fermentation, and for removal of alcohol from wine and beer.
- Food: UF is used to promote safety, quality, and consistency in a variety of food products. Specialized food industry applications of UF include: plant protein isolation and concentration (e.g. soy protein isolate, wheat gluten, etc.), animal protein concentration and purification (e.g., gelatin, egg whites, fish proteins), starch and sugar concentration (e.g. carrageenan, corn wet milling/corn syrup production, etc.), clarification/concentration of fermentation products, plant extract processing, removal of bacteria, and recovery of process streams.
Pharmaceutical & healthcare
The pharmaceutical and healthcare industries rely on ultrafiltration for production of purified water to ensure safety and consistency in products, as well as separation of process streams, and treatment of waste streams for safe discharge or reuse. One important use of ultrafiltration in the pharmaceutical industry is for the recovery of fermentation broths used in the production of antibiotics. Ultrafiltration is also useful for enzyme synthesis, where it can be used to purify filtrate streams and/or concentrate retentate streams, separate out proteins or sugars, or desalt a solution. Within the healthcare industry, ultrafiltration is also used for blood product separation and plasma processing.
The municipal water industry is increasingly adopting UF for efficient removal of contaminants such as bacteria and viruses from drinking water, as UF is capable of removing over 90% of pathogens present in source water. UF is also often used as a pretreatment step to protect RO equipment from premature wear and damage due to solids present in source water.
Pulp & paper
Pulp and paper products require significant water usage at nearly all stages of manufacture. As issues of water scarcity and environmental concerns have made it more expensive to source water and discharge wastewater, the industry has increasingly turned to membrane technologies to cut down on water and energy use. Common ultrafiltration applications within the pulp and paper industry include pretreatment ahead of RO and IX, particularly for treatment of wastewater for recycling, or treatment of process water for reuse.
Other industrial applications
The examples mentioned here reflect just a fraction of UF’s capabilities for specialty applications. Other uses include treatment of process streams for electrocoatings, rinse water recycling in the automotive industry, and degasification for ultrapure water production in the microelectronics industry, among many, many others.
Can SAMCO help?
SAMCO has over 40 years’ experience in the design and delivery of custom ultrafiltration systems for a range of industrial applications, so we welcome any questions you might have regarding your own water treatment needs.
Contact us here to request more information or set up a consultation with an engineer. You can also request a free quote to get a realistic cost for your project. Our team of experienced professionals will walk you through the steps for developing a water treatment or process separation solution that meets your goals and budget.
To learn more about membrane filtration and other process separation technologies, click on over to our blog. There, you’ll find articles on a range of relevant topics, such as:
- Microfiltration vs Ultrafiltration Processes: What is the Difference?
- What is Reverse Osmosis and How Is It Used For Industrial Applications?
- Case Study: UF Wastewater Treatment Solution for a Steel Mill
- What Is Membrane Fouling and How Can You Avoid It?
- What Are the Different Types of Membrane Fouling and What Causes Them?