The EPA and other world health organizations have recognized the dangers and health impacts of being exposed to PFASs.

Federal and State regulators are adopting new guidelines and laws for treating and removing PFASs. Often PFASs within potable drinking water systems or groundwater is contaminated with one of the various types of PFASs. There are over 4700 different variations of PFASs that have variations and at least three polyfluorinated carbon atoms.

Well over 10,000 types of PFASs are introduced into products. That can and has impacted the drinking water quality in the USA and other countries. 

So what are PFASs?

PFASs are fluorinated substances that include at least one fully fluorinated methyl or methylene carbon atom. They do not contain (H/Cl/Br/I atoms). However, any chemical with at least a perfluorinated (CF3) or a perfluorinated (CF2) is a PFAS. There are a few exceptions.

Different subgroups include surfactants, per fluorosulfonic acids, perfluorooctane sulfonic, perfluoro carboxylic, and perfluorooctanoic acids. Often referred to as PFOSs and PFOAs.

PFOS, PFOA, and other PFASs are persistent organic pollutants. They are often referred to as the "forever chemicals" because they do not easily break down in the environment. These organic contaminants are found in humans, animals, and our water supplies across the USA.

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.

Per-and polyfluorinated substances (PFAS) have been used for decades in many consumer products, and they are man-made and have a high residual time in the environment. These chemicals are used for various purposes, including nonstick surfaces, heat protection of circuits, water resistance, fighting fire as they are utilized in fire depression foam, and many other industrial applications. The difficult thing about PFAS is that the very reason they work so well on so many manufactured products is why they are so challenging to get rid of or treat once they have entered the environment or water supply. PFAS are being more and more regulated, and requirements are being put in place by many states and agencies to require the treatment and removal of PFAS and safeguard and protect drinking water.

PFAS are soluble in water, and they are not a volatile organic chemical (VOC), so traditional treatment methods such as utilizing an air stripping tower or degasification system are not effective methods to remove PFAS. One of the first technologies to remove PFAS from drinking water and the environment is activated carbon absorption. In recent years, utilizing ion exchange resins has proven effective and is gaining popularity for the treatment method. Ion exchange resins attach and bond with the PFAS and remove it effectively from the water. Some chemicals tested and studied with success include perfluorooctanoic acid (PFOS). In addition to these technologies, reverse osmosis utilizing high-pressure membranes has an 80-90% effective rate and has proven to be technically efficient in removing PFAS. An R.O. process produces a concentrated waste stream.

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 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 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 from 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 another form of an oxidizing agent. Aeration 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 have the need to remove naturally occurring iron (Fe) from the water to both prevent damage to other equipment as well as to improve water quality. To remove iron from the water it first must 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, causing stains on buildings, on plumbing fixtures. Iron also promotes and facilitates the growth of iron bacteria in water which creates a problem for distribution lines and piping systems. Once the lines become blocked this impacts the ability to distribute water to the customer. The presence of iron bacteria also becomes detectible even at low concentrations and impacts 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 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 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 use, 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.