M.W. Watermark Offers a Full Range of Laboratory Services

M.W. Watermark Laboratory ServicesLaboratory services can help determine the most effective filter press equipment, equipment sizing, filtration media required, and dewatering techniques for your specific application. This includes the recommended treatments, chemicals, and dosages required to form an ideal cake in a filter press.

Our services range from feasibility testing of your materials to offering portable pilot units for on-site testing. We can determine the most effective feed pressures, fill times, filter media and sludge conditioning.

Laboratory services can help you ensure a better informed equipment purchase, or maintain maximum performance of your current filter press, including most makes and models.

M.W. Watermark Lab Filter Press Cake - Laboratory Services
Lab cake sizes available from .75″ to 2.00″
M.W. Watermark 320mm Pilot Filter Press - Laboratory Services
M.W. Watermark 320mm Pilot Filter Press
M.W. Watermark has recently added Frazier® Air Permeability Testing to our growing list of laboratory services.

By using a Frazier® Air Permeability Tester, we are able to determine the air permeability of a particular filter cloth fabric, utilizing the ASTM D 737-96 standard test method for textile fabrics.

M.W. Watermark Air Permeability Testing - Laboratory Services
M.W. Watermark Air Permeability Testing Station
How does it work?

A sample is placed on the machine and air is drawn through the fabric. The rate of air flow passing through a fabric sample is adjusted to find an air pressure differential between two fabric surfaces. The air permeability of the fabric can then be determined by this air flow rate. The test results are reported in CFM, or Cubic Feet per Minute.

Efficiency of filtration media is directly related to air permeability. By testing the air permeability of a filter cloth fabric, our lab technicians are able to determine the filtration characteristics and determine if a given fabric is ideal for a customer’s particular dewatering application.

M.W. Watermark Air Permeability Testing - Laboratory Services
Venturi nozzles of increasing diameters – used to measure air flow

When a customer is looking to replace their existing filter press cloths, and the type of fabric is not known, the air permeability test also helps us match a customer’s cloth sample with the correct fabric spec. In turn, we are able to test for quality control and performance specs of incoming rolled goods.

Contact M.W. Watermark to learn more about our laboratory services.

About M.W. Watermark

M.W. WATERMARK wants to make a difference. We are passionate about the world’s water. We are innovative, focused on customer service and always try to exceed expectations. We are an environmentally conscious company with people who are energized, encouraged and inspired to make a difference on our planet by helping to keep our shared, finite water supply clean and usable for generations to come. We build amazing, custom water and wastewater treatment equipment. Together, we can make a difference.

The product names, logos, brand names, and other trademarks listed above are the intellectual property of their respective trademark owners; M.W. Watermark is not affiliated with such trademark owners in any way.

How Recycling Car Wash Wastewater Benefits Business

Recycling car wash wastewater is an often-overlooked way to cut costs, ensure company sustainability, and help the environment. Learn more about the benefits of car wash wastewater treatment and how the process works.

Why Recycle Water?

It’s no secret that humans consume millions of gallons of water per day. A typical car wash owner’s business pumps out 10 to 15 gallons of “dirty” water with every cycle. What if there was a way to recycle some of this water for subsequent washes? Most business owners aren’t aware that there is a clean way to do this: with a dewatering machine known as a filter press.

There are many models of filter presses available at varying sizes and configurations. Car wash wastewater treatment can help reduce costs by potentially lowering disposal costs. Plus, using water filtration systems deters possible usage restrictions placed upon the company and provides environmental benefits to the area by increasing the natural flow and growth of local ecosystems.

M.W. Watermark Car Wash Wastewater Treatment Equipment - Filter Press

The Water Recycling Process

Water recycling makes use of filter presses to separate liquids from solids. Filter presses can be purchased as new or rebuilt equipment. Instead of going into the sewer or out into the environment, water containing particles of dirt, mud, and other debris enters the filter press.

Up to 50% of the “dirty” water goes through a pressure filtration process and unwanted debris is removed from the water. Best of all, the dewatering process often keeps the cleaning agents in the filtrate for additional uses. By keeping dirty water out of the local ecosystem, car wash operators can utilize a cost-effective solution that simultaneously benefits their surrounding water sources.

For business owners hoping to one day expand their business, undergoing car wash wastewater treatment using a filter press is a no-brainer. M.W. Watermark provides businesses with filter presses crafted from high quality parts. With years of experience, we are prepared to customize the ideal wastewater treatment solution for your company. Best of all, all of our equipment is made in the U.S.A. by professionals who are passionate about water preservation and future sustainability.

Contact M.W. Watermark to learn more about car wash wastewater treatment equipment.   

About M.W. Watermark

M.W. WATERMARK wants to make a difference. We are passionate about the world’s water. We are innovative, focused on customer service and always try to exceed expectations. We are an environmentally conscious company with people who are energized, encouraged and inspired to make a difference on our planet by helping to keep our shared, finite water supply clean and usable for generations to come. We build amazing, custom water and wastewater treatment equipment. Together, we can make a difference.

The product names, logos, brand names, and other trademarks listed above are the intellectual property of their respective trademark owners; M.W. Watermark is not affiliated with such trademark owners in any way.

Benefits of Lime Softening for Municipal Waterworks Sourcing Groundwater

Municipal waterworks generally choose water softening treatment methods as a function of cost, water quality, infrastructural capacity, and the degree of hardness the customers demand. As a rule, lime softening water treatment works best in systems that source groundwater with low to undetectable non-carbonate hardness levels. Softening water with high non-carbonate hardness may necessitate the combination of lime and soda ash. In either case, lime softening is ordinarily more economical than the alternative method of water treatment with caustic soda.

M.W. Watermark - Filter Presses for Lime Softening Water Treatment Application
Two M.W. Watermark 1500mm Filter Presses

Benefits of Lime Softening

Lime softening water treatment not only effectively reduces the dissolved mineral quotient in municipal and industrial water supplies but it also directly and positively impacts municipal, commercial, and consumer budgets. Because softened water tends to form less scale, consumers use fewer household cleaners, which in turn reduces the toxic chemical content of municipal greywater. As a result, filter presses at greywater treatment plants, and industrial efforts like laundry wastewater recycling, operate more efficiently and cost-effectively.

Other potential plusses of lime softening water treatment include the removal of heavy metals, radioactive elements, and other toxins such as radium 226 & 228, uranium, and arsenic. Lime softening eliminates iron, manganese, silica and fluoride, as well as certain organic compounds and possibly even Giardia lamblia cysts. Lime softening water treatment reduces total organic carbon (TOC) content and surface water turbidity. Simultaneously, it increases the Langelier Saturation Index (LSI), which in some cases can aid in pipe corrosion control.

Innovative, Eco-Sustainable Cake Disposal

Proper disposal of the filter press cake produced by lime softening is strictly regulated and often costly. One uniquely beneficial disposal solution is the recycling of the filter cake as agricultural fertilizer. This calcium-rich product can then be distributed or monetized either to restore the pH balance in poor or depleted soil to promote plant growth or as a liming material for farmers.

In states where abandoned strip mines leach acid water into the watershed, pumping a solution containing filter cake from lime softening water treatment into the mines can help abate environmental pollution downstream—by neutralizing the acid water at the source of contamination. In this way, governments can reclaim blighted land to provide economical discharge storage to save on material treatment costs, while at the same time helping to conserve local water resources by reducing pollution—all long-term, cost-saving benefits.

Contact M.W. Watermark to learn more about lime softening water treatment.

About M.W. Watermark

M.W. WATERMARK wants to make a difference. We are passionate about the world’s water. We are innovative, focused on customer service and always try to exceed expectations. We are an environmentally conscious company with people who are energized, encouraged and inspired to make a difference on our planet by helping to keep our shared, finite water supply clean and usable for generations to come. We build amazing, custom water and wastewater treatment equipment. Together, we can make a difference.

The product names, logos, brand names, and other trademarks listed above are the intellectual property of their respective trademark owners; M.W. Watermark is not affiliated with such trademark owners in any way.

How Drought-Stricken California Recycles Wastewater

Wastewater treatment professionals know that water recycling—the process of cleaning and repurposing wastewater—is not a new concept. All kinds of industries reuse water in their operations, including industrial laundries, car and truck washing facilities, metal finishers, and more. Municipal wastewater treatment facilities also recycle, collecting water from sewage, cleaning it, and using it for nonpotable purposes, such as landscaping and agriculture.

A growing number of local governments, however, are taking their water recycling efforts a step further, treating wastewater well enough that it becomes potable, or fit for human consumption and use. California has been leading this charge in the face of ongoing problems with drought and an ever-increasing population.

M.W. Watermark - Wastewater Treatment - Water Recycling

The West Coast Solution – Wastewater Treatment

Beginning with the Groundwater Replenishment System in 2008, Orange County, California has been replenishing the water supply of over half a million residents with thoroughly treated wastewater. Their equipment handles upwards of 100 million gallons of wastewater every day, and the scope of the operation has caught the eyes of water treatment officials from around the world.

Because of the area’s struggles with drought, the Orange County system has pioneered “indirect” reuse, a system which puts an environmental buffer—usually a groundwater basin or reservoir—between wastewater treatment and the municipal water supply. Their three-step treatment strategy has also become an industry standard, using microfiltration, reverse osmosis, and an ultraviolet treatment combined with hydrogen peroxide to restore wastewater to the quality of distilled water.

Looking to The Future of Water Reuse

Following California’s model, some municipalities across the United States have been using wastewater treatment solutions to solve problems they face locally. In the Pacific Northwest, for example, states have been experimenting with water reuse to address wastewater temperature regulations.

It’s also catching on that recycling water is not only a way of saving money but also a benefit to local ecosystems. Freshwater lakes and rivers are no longer the only sources of potentially potable water, and sustainable reuse prevents polluted wastewater from ending up in these ecosystems in the first place.

While water reuse is expensive and requires a lot of energy, the costs are still less than the traditional method of finding and importing water from new sources. And although winning over public opinion about reusing wastewater is a challenge, California’s successful model is increasing public awareness and acceptance. With more public outreach, continued improvements in wastewater treatment technology and practices, and innovative new ways of thinking about water recycling, the future of sustainable potable water looks bright.

Contact M.W. Watermark to learn more about recycling water using wastewater treatment equipment.  

About M.W. Watermark

M.W. WATERMARK wants to make a difference. We are passionate about the world’s water. We are innovative, focused on customer service and always try to exceed expectations. We are an environmentally conscious company with people who are energized, encouraged and inspired to make a difference on our planet by helping to keep our shared, finite water supply clean and usable for generations to come. We build amazing, custom water and wastewater treatment equipment. Together, we can make a difference.

The product names, logos, brand names, and other trademarks listed above are the intellectual property of their respective trademark owners; M.W. Watermark is not affiliated with such trademark owners in any way.

Choosing the Right Hydraulic System and Controls for Your Filter Press

Hydraulic Systems, Control Elements and the Filter Press

The type of hydraulic system best suited for a dewatering application typically depends on the size of the filter press required. Three common types of filter press hydraulic systems include air-operated, electric and manual.

Filter press controls are a factor of both the type of hydraulic system that will be utilized, as well as other specifics such as the options for automated valves, drip trays, an automatic plate shifter, and/or an automatic high pressure cloth washing unit. Various manifold processes can also be more easily facilitated by the use of proper controls, such as Air Blow, Even Fill, Pre-Coat, Acid Wash, Core Blow, Cake Wash, and more.

M.W. Watermark’s team of filter press experts can work with you to determine the best hydraulic system, controls, and other options for your particular dewatering project. Retrofits are also available. 

Air-Operated Hydraulics and Controls

For filter press sizes 630mm through 1000mm, air hydraulics are included as standard.

M.W. Watermark 630mm Filter Press with Air-Operated Hydraulics
M.W. Watermark 630mm Filter Press with Air-Operated Hydraulics
How does an air-powered hydraulic pump work?

For added operator and equipment protection, the hydraulics are enclosed within the leg of the filter press that supports the hydraulic cylinder. 100 psi air is used to pressurize an oil reservoir that is used to push the plate stack closed. Once the plate stack is closed, a high pressure air-operated hydraulic pump clamps the plate stack with a force, plus a safety factor, to counteract the pressure of the slurry feed.

Air-powered hydraulic pumping units convert plant air to hydraulic pressure through a simple ratio system that uses a large air piston area at low pressure to produce a high hydraulic pressure on a small area hydraulic piston. Automatic reciprocation is controlled by the action of a pilot operated selector valve in the pneumatic section of the pump.

As the hydraulic output approaches the desired pressure dictated by the air pressure regulator setting, the pump slows down and finally stalls when the hydraulic force balances the air force. Hydraulic force is maintained with no consumption of power.

M.W. Watermark 630mm Filter Press - Inside the Air-Operated Hydraulic Cabinet
M.W. Watermark 630mm Filter Press – Inside the Air-Operated Hydraulic Cabinet

When the cycle is complete, the air-operated hydraulic system releases the pressure within the cylinder and uses air pressure to retract the follower for filter cake discharge. The air hydraulic control switches and gauges are mounted in either the left or right hand side of the leg of the filter press to suit the installation.

Click below to visit our Filter Press Hydraulic Systems webpage and watch a video overview of our air operated hydraulic system – demonstrating its functionality including closing, clamping and opening times. 

Air Operated Hydraulic Filter Press Overview Video

What control options are available for an air-operated hydraulic filter press?

Visit our Filter Press Controls webpage to learn more.

M.W. Watermark Filter Press with Air-Operated Hydraulics and Optional AFPCS
M.W. Watermark Filter Press with Air-Operated Hydraulics and Optional AFPCS

Electric Hydraulics and Controls

For filter press sizes 800mm through 1500mm, electric hydraulics are optional to decrease filter press opening and closing times.

How does an electric-powered hydraulic pumping unit work?

Electric-powered hydraulic pumping units maintain the hydraulic pressure, and if the pressure exceeds the relief setting this pressure is vented – keeping the pressure within the specified range.

For added operator and equipment protection, the hydraulic power unit (HPU) is enclosed within the leg of the filter press that supports the hydraulic cylinder. The HPU includes a high volume / low pressure pump to open and close the plate stack quickly and a low volume / high pressure pump that clamps the plate stack. Once the plate stack is closed, the high pressure hydraulic pump clamps the plate stack with a force, plus a safety factor, to counteract the pressure of slurry feed.

M.W. Watermark 1500mm Filter Press - Electric-Powered Hydraulic Pumping Unit
M.W. Watermark 1500mm Filter Press – Electric-Powered Hydraulic Pumping Unit

Electric hydraulics are controlled by the M.W. Watermark Electric Hydraulic Control System (EHCS), which monitors the status of the system and provides an emergency stop push button, disconnect switch, and touch screen control of the filter press hydraulics.

Learn more about the M.W. Watermark Electric Hydraulic Control System (EHCS).

M.W. Watermark Electric Hydraulic Control System (EHCS)
M.W. Watermark Electric Hydraulic Control System (EHCS)

Manually-Operated Hydraulics and Controls

A manual hand pump to extend the spring return hydraulic cylinder is standard for the 470mm filter press.

How does the manually-operated hydraulic pump work?

The hydraulic cylinder is swung from the “up” to the “clamp” position and the hand pump is operated to build clamping pressure. At the end of the dewatering cycle, the hydraulic pressure is released and the cylinder is retracted by an internal spring. The cylinder is then lifted to the “up” position and the follower is manually pulled back to the end of the press. The filter plates are then manually shifted to discharge filter cake.

This option requires hands-on “pumping” to get the job done. However, when working with a smaller filter press such as the 470mm, or when an air supply or electrical power is not available on the job site, manually-operated hydraulics may be the best solution.

M.W. Watermark Manually Operated Hydraulics Filter Press

Note: To eliminate the requirement of pumping by hand, an air-operated single-acting closure system (for closing only) is available as an option.

Optional Air-Operated Single-Acting Closure System
Optional Air-Operated Single-Acting Closure System

Click below to watch a video on our Hydraulic Systems webpage on how to open/close a manually-operated hydraulic filter press.

M.W. Watermark Manual Hydraulic Filter Press Video

Contact an M.W. Watermark Sales and Service Team member to learn more. 

About M.W. Watermark

M.W. WATERMARK wants to make a difference. We are passionate about the world’s water. We are innovative, focused on customer service and always try to exceed expectations. We are an environmentally conscious company with people who are energized, encouraged and inspired to make a difference on our planet by helping to keep our shared, finite water supply clean and usable for generations to come. We build amazing, custom water and wastewater treatment equipment. Together, we can make a difference.

Product names, logos, brands, and other trademarks featured or referred to within this document are property of their respective trademark holders. These trademark holders are not affiliated with M.W. Watermark in any way.

Dissolved Air Flotation: A Cost Effective Clarification Technique

When it comes to wastewater treatment, it’s important to utilize a process that handles the job efficiently without breaking the bank. Dissolved Air Flotation (DAF) wastewater treatment is recognized globally as an effective system with low capital and operating costs.

M.W. Watermark Dissolved Air Flotation (DAF) Clarifier
M.W. Watermark Dissolved Air Flotation (DAF) Clarifier

What Makes Dissolved Air Flotation Cost-Effective?

When compared to other technologies such as membranes and centrifuges, the DAF has the least expensive capital cost based on a gallon per minute basis.  The M.W. Watermark DAF is simple to operate and requires minimal maintenance, which makes it ideal for industrial users.  Operating costs are also low because the DAF uses fractional horsepower motors rather than large scale motors many membranes and centrifuges require.

Contact M.W. Watermark to learn more. We will work with you to help determine which wastewater treatment approach is best for your particular application.

About M.W. Watermark

M.W. WATERMARK wants to make a difference. We are passionate about the world’s water. We are innovative, focused on customer service and always try to exceed expectations. We are an environmentally conscious company with people who are energized, encouraged and inspired to make a difference on our planet by helping to keep our shared, finite water supply clean and usable for generations to come. We build amazing, custom water and wastewater treatment equipment. Together, we can make a difference.

Product names, logos, brands, and other trademarks featured or referred to within this document are property of their respective trademark holders. These trademark holders are not affiliated with M.W. Watermark in any way.

Filter Cloths for Large Filter Presses: Mining and Energy Industry Spotlight

More Options, Greater Capabilities and Shorter Lead Times Get You Back Up and Running Faster

M.W. Watermark Filter Cloths for Large Presses; Mining Filter ClothsIn case you haven’t heard, M.W. Watermark makes filter cloths for all makes and models of filter presses, including the large format presses used in the mining and energy industries. Filter cloths can be sewn to the exact specifications of your filter press, guaranteeing a perfect fit.

All cloths are made right here in the U.S.A. in our facility in Holland, Michigan, utilizing two laser cutting tables. Using lasers to cut cloth enables us to provide consistent, high-quality cloths with lower-pricing, while at the same time providing faster turnaround on custom requests.

In addition to our capabilities for customization and short lead times, M.W. Watermark also has industry experts on staff that will work directly with you – to help determine exactly what type and size of filter cloths you need for your particular filter press application.

Visit our Filter Cloths webpage to download our brochure, review FAQs, watch installation videos and more.
M.W. Watermark manufactures large format filter presses and custom filter cloths in-house; Mining Filter Cloths
M.W. Watermark manufactures large format filter presses and custom filter cloths in-house
M.W. Watermark offers filter cloths for the following types of filter plates:
  • Gasketed (CGR) and Non-Gasketed (NG)
  • Centerfeed
  • Cornerfeed
  • Membrane
  • Plate and Frame
Cloths for Gasketed (CGR) and Non-Gasketed (NG) Plates
Cloths for Gasketed (CGR) and Non-Gasketed (NG) Plates
We also offer:
  • Specialized Custom Cloths
  • Rubber Barrel Necks for increased durability to extend the life of cloths utilized in harsh mining and energy applications
  • Options for hook-and-loop material and latex to decrease installation time, improve fitting and minimize leakage
Non-Gasketed (NG) cloth with a rubber barrel neck for increased durability and hook and loop material to minimizes leakage
Non-Gasketed (NG) cloth with a rubber barrel neck for increased durability and hook and loop material to minimize leakage
Below are images of large format filter presses with custom filter cloths made in-house…
M.W. Watermark 1500mm Filter Press - Brine Solution from Water Recovery Application; Filter Cloths for Large Presses; Mining Filter Cloths
M.W. Watermark 1500mm Filter Press – Brine Solution from Water Recovery Application
M.W. Watermark 1200mm Filter Press – Built for a Neutralized Mine Wastewater Application
M.W. Watermark 1200mm Filter Press – Built for a Neutralized Mine Wastewater Application
1200mm Trailer-Mounted Filter Press - Utilized for an Electrolyte Processing Mining Application
1200mm Trailer-Mounted Filter Press – Utilized for an Electrolyte Processing Mining Application
1500mm Tetra Filter Press - Overhead Filter Plate Suspension with Automatic Plate Shifter and Cloth Washer - Filter Cloths for Large Presses
1500mm Tetra Filter Press – Overhead Filter Plate Suspension with Automatic Plate Shifter and Cloth Washer
1200mm Overhead Filter Press with Automatic Plate Shifter - Filter Cloths for Large Presses
1200mm Overhead Filter Press with Automatic Plate Shifter

Contact our Sales and Service Team for a quote or to discuss your particular application. 

About M.W. Watermark

M.W. WATERMARK wants to make a difference. We are passionate about the world’s water. We are innovative, focused on customer service and always try to exceed expectations. We are an environmentally conscious company with people who are energized, encouraged and inspired to make a difference on our planet by helping to keep our shared, finite water supply clean and usable for generations to come. We build amazing, custom water and wastewater treatment equipment. Together, we can make a difference.

Product names, logos, brands, and other trademarks featured or referred to within this document are property of their respective trademark holders. These trademark holders are not affiliated with M.W. Watermark in any way.

Advances in Wastewater Treatment: From Sludge to Clean Water

When discussing municipal wastewater treatment equipment, “sludge” is the term used to signify a toxic semi-solid slurry made up of all of the different types of wastewater that end up at a water treatment plant via sewage systems. Sludge typically is a kind of toxic cocktail made up of industrial waste, hospital waste, commercial waste, human excreta, stormwater runoff, and many other kinds of hazardous, toxic, and biological waste materials, including heavy metals, steroids, and pharmaceuticals.

Sludge Must be Returned to a Non-Hazardous State Using Advanced Wastewater Treatment Equipment

When sludge accrues in a water treatment facility, it must eventually be restored to a non-hazardous state through a highly advanced filtration process. Due to the preciousness of our planet’s limited water supply and the serious effects of improperly treated water to the health of consumers, water treatment facilities and wastewater treatment equipment must remain constantly adaptable to advancements in technologies with regards to sludge water treatment. Legal regulations examine and dictate stricter sewage guidelines, which require treatment plants to adopt new and constantly more efficient standards and methods.

The most recent requirements in agricultural treatments, for example, require that filtration systems are able to reduce the presence of toxic particles in wastewater (or sludge) and wastewater treatment equipment by at least 20 percent within the course of two years. Effectively, this means that the current most common means of dealing with wastewater sludge, a process called “membrane filtration” must update and improve its methods and components.

M.W. Watermark Tubular Microfiltration Membrane Modules
M.W. Watermark Tubular Microfiltration Membrane Modules

How Membrane Filtration Works for Wastewater Treatment

Membrane filtration, the most advanced sludge filtration process in use by most water treatment facilities, utilizes very small filters to trap not only toxic particles, but also microorganisms, such as bacteria or viruses. The process is similar in theory to the process by which home pool filtration systems operate. The process of membrane filtration, used to separate the damaging particles from sludge, is sometimes used in conjunction with other processes to restore sludge into a type of commercial fertilizer.

At M.W. Watermark, our membrane microfiltration process prevents many types of pollution from contamination and chemicals. To learn more, explore our line of tubular membrane modules.

About M.W. Watermark

M.W. WATERMARK wants to make a difference. We are passionate about the world’s water. We are innovative, focused on customer service and always try to exceed expectations. We are an environmentally conscious company with people who are energized, encouraged and inspired to make a difference on our planet by helping to keep our shared, finite water supply clean and usable for generations to come. We build amazing, custom water and wastewater treatment equipment. Together, we can make a difference.

Product names, logos, brands, and other trademarks featured or referred to within this document are property of their respective trademark holders. These trademark holders are not affiliated with M.W. Watermark in any way.

Precoat: What It Is and How to Apply in a Filter Press

Often the effectiveness of an industrial filter press is judged based on the clarity of the liquid exiting the filter. Of course, for many industrial processes the flow rate, or how fast the liquid can be filtered, is critical as well. An ideal system filters a maximum amount of impurities while at the same time providing minimum restrictions on flow. Adding a precoat to filtration equipment can greatly improve the clarity of the output without sacrificing flow rate. It can also help prolong the life of the filter cloth.

What is Filter Press Precoat?

Precoat material is any porous substance that allows liquid to pass through. Common precoat materials are diatomaceous earth, perlite and cellulose. The viscosity of the liquid and the size of the impurities will determine how coarse or fine a precoat should be. The substance should be fine enough to mix with water but not so fine as to be impassable. It is the gaps within the substance that will provide much of the actual filtration.

For example, perlite is milled as lightweight bubble structures of various grades to produce specific flow characteristics. These structures utilize jagged interlocking structures to create billions of microscopic channels between particles to produce ideal flow rates across a variety of applications.

Perlite can be used as a filter aid for filter press precoat
Perlite is a lightweight filter aid and utilizes billions of microscopic channels between particles

How is Precoat Applied?

The precoat substance is usually mixed with water to form a slurry. That slurry is then passed through the actual filter medium until the water is clear and the precoat forms a filter cake on top of the filter cloth. The cake becomes the first point for input. Before the liquid to be purified hits any other filter press parts, it passes through the cake where the microscopic nooks and crannies between the precoat trap irregular particles while allowing the liquid to pass.

M.W. Watermark - Cellulose can be used as a filter press precoat
Cellulose can be used as a filter press precoat

How Does Precoat Benefit Filtration?

Precoat provides numerous benefits to the filtration process. Aside from improving the clarity of the filtrate by adding an extra filtration layer, it significantly prolongs the life of the filter cloths. Without a precoat, the impurities removed from the liquid can bind directly to the filter medium. This can blind or damage the filter medium and require cleaning or replacement sooner rather than later.

A precoat captures these impurities and creates a cake that breaks away cleanly from the filter cloth. An easier cake release can reduce the amount of filter cloth cleaning required, thus potentially reducing manpower requirements and increasing productivity.

M.W. Watermark - Along with other benefits, precoat allows for the filter cake to break away cleanly from the filter cloth
Along with other benefits, precoat allows for the filter cake to break away cleanly from the filter cloth

M.W. Watermark can recommend the best precoat option for your filter press application. Contact us to learn more.

About M.W. Watermark

M.W. WATERMARK wants to make a difference. We are passionate about the world’s water. We are innovative, focused on customer service and always try to exceed expectations. We are an environmentally conscious company with people who are energized, encouraged and inspired to make a difference on our planet by helping to keep our shared, finite water supply clean and usable for generations to come. We build amazing, custom water and wastewater treatment equipment. Together, we can make a difference.

Product names, logos, brands, and other trademarks featured or referred to within this document are property of their respective trademark holders. These trademark holders are not affiliated with M.W. Watermark in any way.

A Filter Press Is a Depth Filter: The Role of Filter Cloths and Cake in the Dewatering Process

Depth filters are innovative pieces of technology that allow particles to collect throughout the medium, not just on the surface. The filter cloth is an integral part of the filter press, collecting particles to separate solids from liquids.

What Sets Depth Filters Apart?

A depth filter, as the name suggests, collects particles throughout the filter medium instead of just on the surface. The unique, porous filtration medium efficiently removes particles from liquids. These filters can also provide filtration to a slurry that contains a higher than normal load of particles without degrading in its quality or letting particles through. Depth filters have a number of sizes and purposes and can be used in potable water treatment, wastewater treatments plants, and more.

M.W. Watermark - A Filter Press is a Depth Filter: The Role of Filter Cloths and Cake in the Dewatering Process

Cake Formation is a Unique Benefit of a Filter Press

Simply put, cake formation is not possible in other types of filters. At the beginning of each filtration cycle, the filter cloth is the primary separator of solids from the liquid stream. Then, as solids build up on both sides of each filter press chamber, the solids become the primary separator, and a “depth filter” is formed in each chamber. This allows for the separation of particles much smaller than the openings in the filter cloth.

As this trapping intensifies, the finer particles become solid throughout the filter plate chamber, like partially hardened mud. This is referred to as the “filter cake” and is often described as a “slab of fudge” as this summarizes its ideal consistency.

M.W. Watermark: A piece of filter cake from a filter press, described as a "slab of fudge"
A piece of filter cake from a filter press, described as a “slab of fudge”

How Do You Know It’s Working?

When the chambers of the filter press are full, the fill cycle is complete. Throughout the fill cycle, the liquid exits the filter plate pack through the corner ports in the manifold, plumbed to exit through a single point. At the end of the cycle, if the filter cake is less than solid, then the cloth may have become clogged. While installing or changing a filter cloth is not the easiest of jobs, M.W. Watermark technicians can perform this task swiftly at a low price, resulting in minimal downtime.

For more detailed information about how a filter press works, visit our Filter Press 101 blog posting.

Contact an M.W. Watermark Sales & Service Team member to discuss your particular application.

M.W. Watermark - A filter press serves as a depth filter

About M.W. Watermark

M.W. WATERMARK wants to make a difference. We are passionate about the world’s water. We are innovative, focused on customer service and always try to exceed expectations. We are an environmentally conscious company with people who are energized, encouraged and inspired to make a difference on our planet by helping to keep our shared, finite water supply clean and usable for generations to come. We build amazing, custom water and wastewater treatment equipment. Together, we can make a difference.

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