DELOACH BLOG

Water demineralization is also called deionization and is a process known as “Ion Exchange.”

In simple terms, water demineralization is “Water Purification.” The process involves removing dissolved ionic mineral solids from a feed-water process, typically for “Industrial” water applications. Still, it can also be utilized to remove dissolved solids from a water process for “Aquaculture,” “Food and Beverage,” and the “Municipal” markets.

Why is demineralization utilized? It can remove dissolved solids to near distilled water quality at a much lower capital and operational cost than other treatment processes such as membrane softening (Reverse Osmosis). Demineralization applies the science known as “Ion Exchange,” which attracts negative and positive charged ions and allows either to attach themselves to a negative ion depending on their respective current negative or positive charge during what is known as a resin cycle. In other technical articles, we will explore and go into more specific details on the science of the ion exchange process. Water that has dissolved salts and minerals has ions, either negatively charged ions known as “Anions” or positively charged ions known as “Cations.” To treat the water and remove these contaminants, the ions in the water are attracted to counter-ions, which have a negative charge. In a demineralization treatment process, there are pressure vessels that hold resin beads which are typically made of plastic. The beads are made from a plastic material with an ionic functional group that allows them to hold and maintain an electrostatic electrical charge. Some of these resin groups are negatively charged, referred to as “Anion” resins, while others hold a positive charge and are called “Cations” resins.

There are different applications to apply Ion exchange technologies, which is why you will often hear different terminology interchanged like deionization and demineralization. The raw water quality and the specific application will dictate the type of ion exchange process needed. For example, if the water contains a high level of hardness, the water will most likely contain Ca2+ or Mg2+ dissolved solids possessing a positive charge. To replace these hard ions, it is typical to utilize a resin bed with a salt ion like Na+. As the water passes over the resin bead material within the pressure vessel. The hard ions are replaced with the salt ion; therefore, all the hardness within the water is removed. However, the water will now contain a higher concentration of sodium ions, and this must be considered during the evaluation and selection process of the type of resin material to utilize for the specific application. If the water application requires high purity and the removal of as many solids as possible, then the term or process selected is referred to as demineralization.

Industrial water systems use water filters to reduce the level of solids in water from:

• Industrial
• Semiconductor
• Manufacturing
• Refining
• Oil and Natural Gas Production Processes

The wastewater may contain harmful chemicals to humans, plants, or animals. Three types of filters are commonly used in industrial settings:

Gravity filters, pressure filters, and constructed wetlands. Pressure filters have two variations: multimedia and higher-pressure micron or cartridge filters. Constructed wetlands or natural filters are not often utilized in industrial processes. Based on the requirements to obtain environmental permits and safeguard the ecosystem.

There are many benefits to pressure filtering systems in industrial wastewater. Pressure filters can remove particles down to 0.3 microns in size. They don't clog up as quickly as other filter types, and it's much faster than other types of filtration methods.

Pressure filtering is also very cost-effective because it uses less energy than other methods. Look no further if you're looking for a high-quality industrial water filter that cuts down on operating costs!

Pressure Filters  (Multimedia type) are often used in industrial settings to filter particulates down to 15 microns in size.

They're also very cost-effective due to their energy; pressure filters utilize much less energy than other filtration methods. Pressure filters can include multimedia, a mixture of gravel and sand, multimedia, gravel, sand, and anthracite, or multimedia, which combines gravel, sand, greensand, and anthracite filter media. The variations are dependent on the applications and the need.

Per- and polyfluorinated substances (PFAS), known as "forever chemicals," have long been utilized in various consumer products due to their exceptional properties.

However, the challenge lies in effectively treating or eliminating PFAS once they enter the environment or water supply. This blog will focus on the technological advancements in removing PFAS and perfluorooctanoic acids (PFOAs) from water sources. By exploring different treatment methods, such as activated carbon absorption, ion exchange resins, and reverse osmosis, and simply avoiding PFOA and PFOS, we can better understand the available options for mitigating these persistent chemicals in water.

Activated Carbon Absorption

One of the earliest technologies employed for PFAS removal is activated carbon absorption. This method involves the use of specially treated carbon materials that effectively adsorb PFAS compounds from water sources. The activated carbon's large surface area and porous structure allow it to trap and retain PFAS molecules. This technology has proven effective in removing PFAS, including PFOAs, from drinking water and environmental sources. However, periodic treatment and regeneration of the activated carbon are necessary to maintain its efficacy.

In water treatment, it is often required to remove small particulate matter from the raw water.

One of the most cost-effective ways to accomplish this is with a pressure filter. Sometimes referred to as “sand filters,” a pressure filter consists of a rigid filter vessel capable of withstanding internal pressure, combined with pipework to distribute and collect water and one or multiple types of filter media. Pressure filters are commonly used in municipal water systems, industrial facilities, residential well water systems, and swimming pools. Typical pressure filter construction is shown below:

At the top of the filter vessel, a distributor is used to break up and distribute the water flow so that there are no concentrated flow jets that stir up the media bed. Inflow distributors are usually oriented to direct flow at the top of the vessel to disperse the flow further. Below the distributor is the primary filter bed. The filter bed contains fine-grained media, most often sand, including crushed anthracite coal, activated charcoal, garnet, or other granular bulk products. The media bed is the thickest layer in the filter vessel and is the region that does the actual filtering of the water or other fluid. Below the media bed will be one or more support layers. These will usually be larger-sized gravel that is chosen to support the filter bed while allowing high flow through the support layer and into the outflow header. The outflow header can take several forms but is often composed of a large central pipe with multiple smaller pipes or “laterals” attached. The laterals are slotted or perforated. This allows the pressurized water to flow into the laterals and out through the outflow header into the downstream components of the water treatment system.

One issue that I run into relatively often with new technicians, or with some non-technical project managers is confusion over pipe sizing. 

A typical example looks like this: I ask a new technician-in-training to get me a count of the 1-inch pipe that we have in storage. I take the info, and then later find out that what the trainee inventoried was the 3/4-inch pipe. The reason for this confusion lies in the way that pipe sizes are named. The 1-inch, 3-inch, 6-inch, etc. pipe designations are closer to names than sizes. This is because pipe sizing goes by a nominal size standard which is somewhat non-intuitive.

For many people, if they are asked to locate a pipe of a given size, 3-1/2” for example, they will take a tape measure and instinctually measure the outside diameter of the pipe, which will lead them to an incorrect identification. This has to do with the sizing conventions for pipes. Pipes are sized using a nominal pipe size (NPS) designation, and a pipe schedule (SCH) to fully define the size. The nominal size refers only to the approximate inside diameter, and the schedule refers to the wall thickness of the pipe. Because of this, the inner and outer dimensions of a pipe do not directly align with the “name” of the pipe size

In process control systems, it is often required to handle fluids that have a harsh chemical nature. In these cases, it is necessary to be aware of material-chemical compatibility. Chemical compatibility is a general term referring to the way a specific chemical interacts with a specific material. This information is taken into consideration when selecting materials for construction for tanks, valves, pipework, tubing, and other devices that may encounter harsh chemicals. Common chemical types that are used in process systems are acids, bases, corrosives and oxidizers, and hydrocarbons. Typical chemical-resistant materials include natural and synthetic rubbers, vinyl polymers, fluoropolymers, and stainless steel. In order to determine which materials are compatible with certain chemicals, a chemical compatibility chart is often used. A chemical compatibility chart contains tabulated data about how a given material interacts with a given chemical.

Often, the manufacturer of the equipment or material in question will have their own compatibility chart for their specific goods. Most compatibility charts will have the same type of information. Materials will be categorized along one axis of the table, with fluids or gasses categorized along the other axis. At the intersection of a material with a fluid, you will find an indication of the level of compatibility. Some charts will use an A-F categorization, others may use a more graphical style. Most charts will be accompanied by a key or guide that explains how to use the table. There may also be multiple concentration levels and temperature ranges for a given fluid in cases where the distinction makes a difference with compatibility.

Converting Ferrous (Fe+2) (soluble) iron to Ferric (Fe+3) (Particulate/Solid form).

The iron must first be exposed to air or an oxidizing agent. Aeration System is the most cost-effective method to oxidize ferrous iron for its removal from water. In many areas around the globe, municipal and industrial operations need to remove naturally occurring iron (Fe) from the water to prevent damage to other equipment and improve water quality. Removing iron from the water must first be oxidized using the most widely accepted and cost-effective method called aeration. The aeration process changes the iron from its Ferrous (Fe+2) state (soluble) to ferric (Fe+3) colloidal participation. Did you know that Iron occurs naturally and is found in the earth’s crust? It occurs in both groundwater as well as surface waters and is not known to cause any harmful effects on humans or animals.

Iron does cause problems, though, for municipal facilities and their customers by impacting laundry operations and causing stains on buildings and on plumbing fixtures. Iron also promotes and facilitates the growth of iron bacteria in water, creating a problem for distribution lines and piping systems. Once the lines become blocked, this impacts the ability to distribute water to the customer. Iron bacteria also become detectible even at low concentrations and impact the taste of the water. The U.S. Public Health Service Drinking Water Standard set a recommended maximum level of 0.3 mg/L in public water supplies.

In industrial applications, iron can cause server damage in boiler systems.

Cation and Anion systems, piping and nozzles, and other equipment. In addition, for other industries such as food and beverage, brewery, semiconductor, or the production of chemical products, iron can interfere with the manufacturing or brewing and canning process, lowering the quality of the final product. In groundwater and anaerobic surface water, iron is normally present in its soluble form called “Ferrous” iron Fe+2 when the pH is in a certain range. When the same water is in contact with air, that allows the air to diffuse into the water, or when any form of an oxidizing chemical is added to the water, the iron is converted into its oxidized form called “Ferric” Fe+3, becoming a solid. The ferric iron becomes visible and impacts the turbidity of the water and is typically not accepted by customers because the ferric iron within the water when in contact with surfaces, will create colloidal precipitates causing discoloring to all that it encounters over time.

In water treatment systems it is often important to measure the rate at which water is flowing through the system. Data from flow measurement devices can be used to control chemical dosing, set pump speeds, control filter loading rates, inform maintenance programs, and other tasks necessary for the operation of a water treatment facility or on key components such as Degasification and Decarbonation systems or Biological Odor Control Systems. As with most types of instrumentation, there is an array of technologies that can be used for the task, each one with various strengths and optimal applications. For modern electronically controlled systems, the most common types of flow sensors used are axial turbine flowmeters, paddlewheel flowmeters, differential pressure/orifice plate flow transducers, and magnetic flowmeters. This article will briefly discuss the technology and features of each of these types.

A turbine flow meter,

consists of a tube that contains supports to hold a multi-bladed metal turbine in the center. The turbine is designed to have close clearance to the walls of the tubing such that nearly all of the water is made to flow through the turbine blades as it travels through the pipe. The turbine is supported on finely finished bearings so that the turbine will spin freely even under very low flows. As the turbine spins, a magnetic pickup located outside of the flowmeter housing is used to sense the tips of the turbine blade spinning past the pickup. An amplifier/transmitter is then used to amplify the pulses and either transmit them directly or convert the pulse frequency into an analog signal that is then sent to a programmable controller for further use elsewhere in the system. One advantage of a turbine flowmeter is that the electronics are separated from the fluid path. The magnetic pickup is the only electronic component, and it is installed outside of the turbine housing, reading the presence of the turbine blade tips through the wall of the sensor body. In clean water applications, this can be advantageous because the magnetic pickup can be replaced if needed without removing the turbine from service. However, the turbine itself covers most of the pipe area and creates back pressure in the system, requiring increased pumping energy to move a given amount of water. In Industrial Water Treatment or Filtration Treatment,  turbines can also easily become fouled or jammed if they are used to measure water or other fluids with entrained solids, algae or bacteria cultures which cause significant accumulation, or corrosive chemical components that can degrade the turbine bearings.

In an industrial environment, electric motors are used for a variety of applications.

These often include pumping water or other fluids, transporting material on conveyors or lifts, or providing motive force to moving parts of a mechanical device. The electric motor dominates the field whenever something needs to move. Regardless of the end user, all these motors will have one thing in common, a motor controller.

A motor controller is a device with the means to turn the motor on and off, provide circuit protection, and serve as a disconnecting means to render the circuit safe during maintenance. Traditionally, this is done with a direct-on-line (DOL) motor starter. A DOL starter installation consists of a branch breaker combined with a DOL motor starter and overload module. In a typical DOL motor starter installation, the branch breaker will serve as short circuit protection, as well as a means of electrical disconnect. The motor starter unit is essentially a large relay with a magnetic coil and high-power contacts held apart by springs. When the motor is called to run, the magnetic coil is energized, pulling in the contacts and bridging the line side to the load side terminals, allowing power to flow. Once the motor starter has contact, electrical power flows out through an overload disconnect module, and then to the electric motor. The DOL motor starter is a well-proven design that is familiar to almost anyone in the industrial space and is still what is found in a majority of applications.

In many water treatment and chemical processes,

it is a requirement to keep track of the pH of the water or product stream. In DeLoach Industries equipment such as degasification systems, or odor control scrubbers, pH measurement is critical to control the chemical reactions happening within the treatment system. PH is an indication of the acidic vs alkaline nature of the fluid. An acidic fluid will have a greater concentration of H+ hydrogen ions, while an alkaline fluid will have a greater concentration of OH- hydroxide ions. This electrochemical nature is used in the construction, reading, and maintenance of electronic pH probes.

PH probes are generally glass and will contain a reference element, and a sensing element. When the pH probe is immersed in the fluid to be measured, the electrical potential difference between the sensing element and the reference element is amplified by electronics and the resulting voltage is used in a calculation to determine pH from differential electron potential. As a pH probe remains in service, ion exchange will slowly change the electrical potential of the sensing element, the reference element, or both. This happens because the hydrogen ions are small enough to travel through the glass sensor body and cause reference potential shifts over time. This is normal behavior for all pH probes and is the reason why pH probes must be periodically calibrated.

Calibration is a process where a pH probe is immersed in a series of standardized stable pH solutions called “buffers”. The standard set of buffers includes a pH 4.0 acidic buffer, a pH 7.0 neutral buffer, and a pH 10.0 alkaline buffer. These buffer solutions are chemically designed to hold a stable pH and are used as a reference for the internal calculations that are done by the pH amplifier or transmitter that interprets the reading taken by the pH probe. As the reference voltage vs actual pH for a mature probe changes, the known buffer solution provides a benchmark for the calculation. Each pH instrumentation manufacturer will have a slightly different method for performing a calibration, but in general, the system will have you step through the buffer solutions while an automated routine makes note of the expected voltage vs calibration voltage at each step. The computation algorithm will use this drift information to re-scale the calculation to re-establish accuracy.