Water turbidity refers to how clear or translucent the water is when examining or testing it for any given use.

Water turbidity can impact food and beverage, municipal, industrial, and aquaculture operations. Turbidity is caused by suspended or dissolved particles in the water that scatter light which causes the water to appear cloudy or even murky.

Different types of particles can cause turbidity and they include sediments such as silts and clay, very fine inorganic or organic matter, algae or soluble colored organic compounds, and microscopic organisms. Turbidity is measured in a value referred to as NTU, which means Nephelometric Turbidity Unit. The EPA requires in the USA a turbidity level no higher than 0.3 NTU, and if a member of the partnership of safe drinking water, then the level must not exceed 0.1 NTU.

High turbidity can create habitats for other harmful elements such as bacteria or metals that can accumulate onto the particles. This increases the health risk for a potable water system. In aquaculture operations, increased turbidity from silts and sediments can be harmful and detrimental to marine life, so it must be removed to safe levels. For the food and beverage industry, the impact of high turbidity can be both a safety concern as well as a visual and noticeable quality concern because if the turbidity is high, it can alter the physical look of the final product, for example, a distillery.

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 have impacted the drinking water 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 and 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 and 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. These chemicals started to be banned in 2021 when Maine took the lead as the first US state to implement the ban and discontinue their use by 2030 in all products unless there is no other current option than an exception may be granted.

Water demineralization is also referred to as deionization and as 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 but 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? Well, it can remove dissolved solids down 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 an opposing ion depending on their respective current negative or positive charge during what is known as a resin cycle. We will explore and go into more specific details on the science of the ion exchange process in other technical articles. Water that has dissolved salts and minerals has ions and these ions are either negatively charged ions known as “Anions” or positively charged ions known as “Cations”. In order to treat the water and remove these contaminants the ions in the water are attracted to counter-ions which are ions that have an opposing 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 that has an ionic functional group that allows them to hold and maintain an electrostatic electrical charge. Some of these resin groups are negatively charged and they are 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 and that is why you will often hear the different terminology interchanged like deionization and demineralization. The raw water quality and the specific application will dictate the type of ion exchange process that will be needed. As an 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 and therefore all of 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.

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 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 of 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.

The basics of water decarbonation, the removal of CO2 from water

the removal of carbon dioxide (CO2). The need to remove (CO2) is essential in most Aquaculture, Municipal, Industrial, and Food & Beverage Processes To understand you must familiarize yourself with Henry’s Law.

Henry's Law defines the method and proportional relationship between the amount of a gas in solution

in relationship to the gases partial pressure in the atmosphere. Often you will see and hear various terms like degasification, decarbonation, aeration, and even air stripping when discussing the removal of dissolved gases and other convertible elements from water. Understanding the impacts that Carbon Dioxide (CO2) can have on both equipment and aquatic life provides the basic reasons why the need to decarbonate water, exists. Carbon Dioxide (CO2) can exist naturally in the raw water supply or be the results of ph control and balance. In either case the the process called Decarbonation or Degasification provide the most cost effective and efficient manner to reduce or tally remove (CO2) from the water. In addition to Carbon Dioxide (CO2), water can contain a variety of other contaminants that may impact the removal efficiency of the Carbon Dioxide. A variety of elements as well as dissolved gases such as oxygen, nitrogen and carbon dioxide (CO2). A full analytical review of the water chemistry is required to properly design and size the “Water Treatment” process.

Breaking the bonds in water to release a dissolved gas

such as carbon dioxide (CO2) you must change the conditions of the vapor pressure surrounding the gas and allow the gas to be removed.  There are many variables to consider when designing or calculating the “means and methods” of the removal of carbon dioxide (CO2). When I refer to the means and methods. I am referring to the design of a decarbonator and its components. The means equals the size and type (Hydraulic load) of the decarbonator and the “method” equals the additional variables such as cubic foot of air flow (CFM) and “Ratio” of the air to water to accomplish the proportional condition needed to remove the carbon dioxide (CO2).

A BIOLOGICAL ODOR CONTROL SCRUBBER IS JUST ONE OF MANY DIFFERENT TYPES OF AVAILABLE TECHNOLOGIES

To treat air emissions that may contain harmful gases. This class of equipment commonly falls into a category referred to as “Odor Control Scrubbers” and they are utilized to remove dangerous or noxious odors from an air stream. The Biological Odor Control System has gain popularity among many end users such as municipal operators due to the reduced operating cost and more simplistic operating requirements. A typical chemical odor control scrubber often requires two or more chemical additives, and more instrumentation is required to maintain system performance. With the additional chemicals required and instrumentation comes the need for more hands-on maintenance, calibration, and safety requirements which increases the operating costs and workload of the operator.

A Biological Odor Control System relies on active bacteria cultures that recirculate within a water stream and flow across a random packed media bed that is beneficial to the bacteria culture. During the process of metabolizing harmful gases such as Hydrogen Sulfide (H₂S) the biological odor control system requires only the addition of Caustic to control and balance the pH and additional water makeup to replace what has been consumed through evaporation or during the blow down process to eliminate solids. There are several different types of odor control and chemical wet scrubbers on the market today and each provide a solution for the treatment of noxious or corrosive gases and odors in the industry.  And even though Biological scrubbers are commonly utilized in municipal applications for the treatment of hydrogen sulfide (H2S) gases that were produced by a water or wastewater treatment process there are times when a Biological Scrubber does not provide the best solution for treatment. When there are wide or rapidly changing concentration in the ppm (parts per million) level than a Biological Scrubber will have difficulties balancing and acclimating fast enough to prevent break through.  As an example, In water treatment there is a treatment process referred to as “degasification” which strips the hydrogen sulfide gas from the water and then the concentrated H2S gas is exhausted from the tower through an exhaust port.  When the concentration rises above 1 ppm for hydrogen sulfide gas then the levels become both noxious to the surroundings as well as corrosive. Many times, the levels range from 3-7 PPM in concentration with Hydrogen Sulfide and pose a serious health threat, noxious odor, and corrosive environment demanding capture and treatment. When utilizing an Odor Control Scrubber such as a Biological Scrubber the gases are pulled or pushed through an air duct system that is connected to the Biological Scrubber inlet or suction side of the blower. The same process is utilized when treating Hydrogen Sulfide (H₂S) gases that were captured at a wastewater treatment process. These gases may have been generated from a source such as the wastewater treatment plant, lift station or master head-works facility. When captured the gases are also conveyed in a similar manner to the Biological Odor Control Tower for treatment.

A Biological Odor Control Scrubber is in fact a eco system all to itself. The biological scrubber relies upon an initial seeding of tiny microorganisms (bacteria) which attach themselves to the internal media substrate or packing providing both a place to attach and to breed and multiply all the time coming in direct contact with the contaminated air. The bacteria are utilized to breakdown and digest contaminants, and it feeds on the contaminants as a food source which allows it to not only live but continue to grow and multiply.

When utilizing a Biological Odor Scrubber for hydrogen sulfide (H₂S) treatment and removal the by-product that is produced during the reaction is a waste in the form of Sulphuric Acid which is produced as the Sulphur is consumed as a food source. The Sulphuric acid waste lowers the pH of the recirculating water and can create an unhealthy 

The need to remove harmful elements from water such as Hydrogen Sulfide and Carbon Dioxide

from water in the pisciculture and aquaculture market is extremely important. In order to achieve maximum results, the industry utilizes a treatment technology called “Degasification” and controls the pH precisely to maximize results. When utilizing equipment such as the DeLoach Industries degasification systems the hydrogen sulfide and carbon dioxide levels can be removed to 99.999% ug/l.

The need for pH control with water degasification and decarbonation in water treatment includes almost every industry and includes;

The need for pH control with water degasification and decarbonation in water treatment includes almost every industry and includes; Aquaculture, food and beverage, industrial, municipal, and even pisciculture.  In some water treatment applications, harmful gases such as Hydrogen Sulfide (H2S) are removed, while in other applications, Carbon Dioxide (CO₂) or a combination of both. In addition, there's a host of other organic and inorganic elements found in water, both naturally occurring and manmade, that require removal during some part of the water treatment process.  

In almost every application of degasification or decarbonation, you will hear or see the term pH used either by need or by the result.  If, as an example, the water treatment application requires the removal of Hydrogen Sulfide (H₂S) to be removed either as “free” gas or requires the conversion of Sulfides into (H₂S) gas. You will often also see the need to adjust the pH of the water chemistry to maximize both the removal and the conversion to increase the efficiency of the equipment being utilized to remove the hydrogen sulfide, such as a degasification tower or commonly called a degasifier.

So, what is pH?

Water pH is a term used to describe whether or not the water is “acidic” or “basic.”  pH ranges in water can be from 0-14.  0 is the most acidic, and 14 is at the far end and is the most basic, leaving “7” as the neutral state.  A pH of 7 is neither acidic nor basic. So, what causes pH to be acidic?  In nature, the most common cause of a low acidic pH in water is Carbon Dioxide (CO₂) which occurs naturally when photosynthesis, decomposition, or respiration occurs in nature.  The increase in CO₂ causes an increase in ions, producing a lower pH in a simplified explanation.

How does pH play such a significant role in degasification and decarbonation? 

As mentioned above in the example of the removal of certain harmful elements such as sulfides, sulfates, and free H₂S hydrogen sulfide gases, to maximize the removal from water utilizing a degasification tower, it is important to maintain as close to a pH of 5 as possible.  When the pH rises above 5, the ability to convert and strip the free H₂S gas from the water diminishes.  When a degasification tower operates within this specific range and if it has been designed with the higher efficient distribution systems such as the ones utilized by DeLoach Industries, removal efficiencies of 99.999%- 100% can be achieved.   If the pH rises to a seven or above, the removal process becomes much more difficult, and typically, you will much lower results.  The pH adjustment during the water treatment process is normally accomplished by adding commercially available acid, such as “sulphuric acid,” one of the most common in the municipal and food and beverage industry.

Hydrogen Sulfide Chemical Formula and the Molar mass of H2S

H2S is a naturally occurring chemical compound created in nature with the decay of organic material. Hydrogen sulfide is a chemical compound with a molecular formula comprised of (2) hydrogen atoms and (1) one sulfur atom. The formula is displayed as H2S. The gas is a colorless hydride, often known as the “Rotten egg gas.” This gas is very dangerous as it is poisonous and toxic to all life forms. It is also very corrosive and flammable. The H2S molar mass is 34.1 g/mol, with a melting point of -76 F (-60 C) and a melting point of –115.6F or (-82C).

Hydrogen sulfide gas is also created more often from a byproduct of a manufacturing process or the removal of water or wastewater treatment systems. In wastewater, as organic material decays, H2S is released, captured, and treated to protect human lives, reduce corrosion, and reduce odor complaints. Hydrogen sulfide gas is produced during the manufacturing operations at refineries, pulp mills, and mining. These high levels of H2S are released during manufacturing. They must be captured and neutralized to protect human life from unwanted health effects such as pulmonary edemaand prevent excessive corrosion to your system. You cannot even smell the gas at higher concentrations, and it is not distinguishable as the “rotten egg gas,” which makes it even more dangerous and drives the need for hydrogen sulfide scrubbers equipment, fume scrubbers, or odor control scrubbers.

According to the “Agency for Toxic Substance & Disease Registry,” those who work within certain industries are exposed daily to higher levels of hydrogen sulfide gas than the normal public. Because the gas is also heavier than air, it will settle into lower places like manholes, tanks, and basements, and it will travel across the ground filling in low-level areas. To protect the public, OSHA (occupational safety and health administration) has set guidelines and rules known as “Permissible Exposure Limits” (PEL). A PEL is a legal limit a worker may be exposed to a chemical substance. The PEL limit for hydrogen sulfide is ten parts per million (10 ppm) over eight hours.