Easy Guide to Common Types of Industrial Dirty Water Filters

A Quick Look at Some Common Types of Industrial Water Filters

There are almost as many types of dirty water filter as there are circumstances when you may need to use one. This page presents some common filter types and their typical uses in various conditions.

 Why so many Industrial Water Filters?

The demand for clean – or at least usable – water continues to rise.  Safe drinking water is at a premium – reflected in its higher than ever cost to homes and businesses, and so for most non-potable uses the demand for natural or re-usable water is also on the rise.

Climate change diminishes natural clean water sources through drought and global warming, and increasingly contaminates water sources through flood and deluge.  The quality of much of our natural water is degrading; and the cost of potable water means a greater reliance on the re-use of water and waste water. Pumping and screening dirty water is a growing fact of life.

Which Filter Type?

This article is intended to offer an overview of common types of industrial water filter and their applications, providing a primer for further research.

Selecting the type of filter that best suits a particular application, and its configuration, depends on many factors. Consideration should be given to flow rate, what materials are being screened for, and what size.  The intended location, the water quality (pH, temperature, total suspended solids), and maintenance requirements may also affect the choice of equipment.

The table below gives a broad indication of the characteristics of common types of dirty water filters.

How dirty is the water, and what’s in it?

Filtration can be problematic so it is important to know what you wish to filter for, and equally, what your dirty water filter can and cannot handle. Most dirty water contains a mix of contaminants, unless it is dirty as a result of a specific industrial process. Therefore, the type of filter will depend on the water quality and what it is in the water that causes the most trouble.

Hard solids

Hard solids are relatively easy to filter compared with most organic material because they are less likely to coagulate and block filter mesh compared with softer impurities in water. Most filter types will handle hard solids - the main issue here is sizing the mesh to suit the contaminants.

Living organisms.

Living organisms – algae, biofilms, crustaceans, weed, tadpoles etc – can all affect the performance of filters. Also, many filters present an ideal habitat for many aquatic and marine life forms. The problem with this type of contamination is that it will stick to filter screens and media and is difficult to clean off. Living organisms also slowly grow and cover the filter, eventually causing it to block. Any dirty water filter can be susceptible.

Most filters deal with this well, with regular maintenance to ensure biofilms and algae that slowly grow on the filter screens are kept at bay. In addition, filters used in seawater can be treated with antifouling.

Mixed contaminants

More often than not, natural water will have a mix of hard solids, living organisms and organic matter. For example, leaves, weed, sewage, rubbish. Larger matter is easy to remove, but finer organic particulate - often soft and around the same density as water, can be more problematic.  Filtration systems that self-clean or backwash often deal with this type of contaminant quite effectively.

One of the most common ways to assess the level of contamination in dirty water is to measure the Total Suspended Solids (TSS) in the water. This is the measure of suspended solids by dry weight per litre of water. Some filter manufacturers will use the amount of TSS as a guide to the limits of their filter's capabilities.

Wikipedia has a concise description HERE. The turbidity or haziness of the water serves as a rough guide to the TSS if it cannot be measured.

Filter Types

Of course, water quality is not always consistent and may change as flow rates or other factors vary. What follows are general descriptions of types of industrial dirty water filters and methods of filtration to help in choosing which type of dirty water filter to use.

Centrifugal Separators / Hydrocyclones

A hydrocyclone filter is a device used for separating particles from liquids based on the principle of centrifugal force. It is commonly employed in various industries, including agriculture, mining, and wastewater treatment, to remove sand, silt, and other solid contaminants from water.

Hydrocyclones are typically installed in-line within a piping system, allowing for continuous operation without the need for additional pumps. They can effectively filter particles down to approximately 10 to 20 micrometers, depending on the design and operating conditions.

They are widely used for removing hard solids – for example grit and sand – and for pre-filtering water in irrigation systems, protecting valves and pumps from abrasion, and in processes where solid-liquid separation is crucial.

The hydrocyclone operates by directing the liquid into a conical chamber at high velocity. This creates a vortex that forces heavier particles to the outer wall, where they settle at the bottom, while cleaner liquid exits through the top.

Rotary Drum Filters

A Rotary Drum Water Filter is a type of filtration system that utilizes a rotating drum covered with a fine mesh screen to separate solids from liquids. It operates in a continuous flow manner, making it an in-line filter, meaning it can be integrated directly into a water treatment process without the need for additional tanks or holding areas.

This filter can typically achieve a filtration precision of around 10 to 100 micrometers, effectively removing larger particles, sediments, and some microorganisms from the water. The rotary motion helps to keep the filter surface clean by dislodging accumulated solids, which are then removed from the system.

Rotary drum filters are commonly used in various applications, including wastewater treatment, aquaculture, and industrial processes, where they help maintain water quality by ensuring that contaminants are effectively filtered out before the water is reused or discharged.

Y-Strainer

A Y-Strainer Water Filter is a type of filtration device designed to remove debris and particles from liquids in a piping system. It features a Y-shaped body that allows for easy installation in-line, meaning it can be directly integrated into the water flow without requiring additional components.

Y-strainers typically filter out particles down to about 0.5 to 2 millimeters in size, making them effective for capturing larger sediments, rust, and other contaminants. The strainer consists of a mesh or perforated screen that traps these particles while allowing clean water to pass through.

These filters are commonly used in various applications, including irrigation systems, industrial processes, and HVAC systems, to protect pumps, valves, and other equipment from damage caused by debris in the water supply. Regular maintenance, such as cleaning or replacing the strainer, is essential to ensure optimal performance.

Bag Filters

A Bag Filter Water Filter is a filtration system that uses a fabric bag to capture particles and contaminants from liquids. It is designed to be in-line, allowing it to be easily integrated into existing piping systems for continuous filtration.

Bag filters can achieve filtration levels ranging from 1 to 800 microns, depending on the type of bag used. This versatility makes them suitable for removing a wide range of contaminants, including sediments, dirt, and larger particles.

These filters are commonly used in various applications, such as industrial processes, water treatment, and food and beverage production, where maintaining water quality is crucial. The bags are typically replaceable, making maintenance straightforward and efficient, as they can be easily swapped out when they become clogged or dirty.

Cartridge Filter 

A Cartridge Filter Water Filter is a filtration device that uses a replaceable cartridge to remove impurities and particles from liquids. It is designed to be in-line, allowing for seamless integration into existing plumbing systems for continuous water filtration.

Cartridge filters can provide filtration precision ranging from 1 to 100 microns, effectively capturing sediments, chlorine, and other contaminants. The specific filtration level depends on the type of cartridge used, which can vary in material and design.

These filters are widely used in applications such as drinking water systems, aquariums, industrial processes, and pool maintenance. They are valued for their ease of maintenance, as cartridges can be easily replaced when they become clogged or worn, ensuring consistent water quality and flow.

Media / Sand Filters

Media/Sand Filters are filtration systems that use layers of sand or other media to remove particles and impurities from water. They are typically designed to be in-line, allowing them to be integrated directly into water treatment processes for continuous filtration.

These filters can achieve filtration levels of approximately 20 to 100 microns, effectively capturing sediments, algae, and other larger contaminants. The filtration process involves water passing through the media, where particles are trapped within the layers.

Media/sand filters are commonly used in applications such as swimming pools, wastewater treatment, and drinking water systems. They are known for their durability and ability to handle large volumes of water, making them suitable for both residential and industrial uses. Regular backwashing is required to maintain their efficiency by removing trapped particles and preventing clogging.

Inline Self-cleaning Filter

An Inline Self-Cleaning Water Filter is a filtration system designed to continuously remove particles and contaminants from water while automatically cleaning itself. It is inherently in-line, meaning it can be directly integrated into existing plumbing systems for uninterrupted water flow.

These filters typically achieve filtration levels ranging from 5 to 100 microns, effectively capturing sediments, dirt, and other impurities. The self-cleaning mechanism usually involves a backwashing process that activates periodically or when a certain pressure differential is reached, allowing trapped particles to be flushed out without manual intervention.

Inline self-cleaning filters are commonly used in applications such as irrigation systems, industrial processes, and HVAC systems, where maintaining water quality is essential. Their automated cleaning feature reduces maintenance efforts and downtime, making them a convenient choice for continuous filtration needs.

Run Down / Parabolic Screens

Run Down/Parabolic Screens are filtration devices designed to remove larger debris and solids from water. They feature a parabolic shape that allows water to flow over the screen surface, effectively capturing particles as the water moves downward. These screens are typically in-line, meaning they can be integrated directly into water treatment systems.

Run down screens can filter out particles ranging from approximately 1 to 10 millimeters, making them effective for capturing larger debris such as leaves, twigs, and other coarse materials.

These screens are commonly used in applications such as wastewater treatment, stormwater management, and industrial processes, where they help protect downstream equipment from damage caused by larger solids. Their design allows for easy maintenance and cleaning, ensuring efficient operation in various water treatment scenarios.

Filter Press

A Filter Press is a mechanical device used for separating solids from liquids in various industrial processes. It operates by forcing a slurry (a mixture of solid and liquid) through a series of filter plates, which capture the solid particles while allowing the liquid to pass through. Filter presses are typically not in-line; they are batch-operated systems that require the slurry to be processed in discrete cycles.

Filter presses can achieve filtration levels down to approximately 1 to 100 microns, making them effective for removing fine particles and achieving high solid-liquid separation efficiency.

These devices are commonly used in applications such as wastewater treatment, mining, food and beverage processing, and chemical manufacturing. They are valued for their ability to produce a dry cake of solids, which can be easily disposed of or further processed, while the filtered liquid can be reused or treated as needed. Regular maintenance and cleaning are essential to ensure optimal performance and longevity of the filter press.

Rotorflush Filter / Strainer

A Rotorflush Self-Cleaning Filter is a filtration system designed to continuously remove particles and contaminants from water while automatically cleaning itself. It is designed for use in a water source directly supplying existing piping systems for uninterrupted water flow.

Rotorflush filters typically achieve filtration levels of from 3 mm down to 50 microns, effectively capturing sediments, algae, and other suspended solids and impurities. The self-cleaning mechanism produces a continuous backwash that prevents debris adhering to the filter mesh, cleaning the filter screen, dislodging trapped particles, and pushing them away.  Maintenance is minimal, pumps and connected equipment are protected from clogging and blockages.

These filters are commonly used in applications such as irrigation systems, industrial processes, waste water treatment, raw water intake, sample water filtration and aquaculture, where maintaining a flow of water is crucial. Their automated cleaning feature allows for continuous operation without manual intervention, making them a convenient choice for various water treatment needs.

Call or Email Rotorflush Filters Ltd to discuss your filtration needs in more detail