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.

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 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.

The need to remove harmful water elements, such as Hydrogen Sulfide H2s and Carbon Dioxide CO2, from water in the pisciculture and aquaculture market is extremely important.

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 including; 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 essential 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 seven or above, the removal process becomes much more complex, and typically, you will have much lower results.  The pH adjustment during the water treatment process is typically accomplished by adding commercially available acid, such as “sulphuric acid,” one of the most common in the municipal and food and beverage industry.

Basics of water decarbonation for dissolved organic carbon.

The water treatment industry continues to develop and evolve. Over the past two decades, there have been many new developments in technology and even more refinement in existing technologies such as "Degasification". The evolution and advancement of water treatment have been driven by the constantly increasing demand from an increase in population that demand cost-effective solutions and recognition to improve safety with the implementation of NSF 61 standards.

All human cultures on our planet share a single commonality: the dependency on water to survive.

Many existing technologies, such as "Degasification," have evolved with higher efficiency to meet the demand changes and provide safety to consumers and the systems. Degasification refers to the removal of dissolved gases from liquids, and the science to degasify water is based upon a chemistry equation known as "Henry's Law". The "proportionality factor" is called Henry's law constant" and was developed by William Henry in the early 19th century. Henry's Law states that "the amount of dissolved gas is proportional to its partial pressure in the gas." The most "cost" effective method to perform degasification is with the packed vertical tower called a "Degasifier” or “Decarbonator.”

The key words in this previous sentence for owners, operators, and engineers to focus on is "the most cost-effective" as there is no other process more cost-effective at removing dissolved gases at the lowest cost than using a Degasifier or decarbonator. The process of degasification is simple enough to understand. Water is pumped to the top of a vertically constructed tower, where it first enters the tower through some type of distribution system at the same time, there is a cross-current air flowing up from the bottom by a blower located at the bottom of the tower, and the air encounters the water and is exhausted at the top of the tower through an exhaust port. There are various types of distribution systems, and we will explore these in later discussions. Once the water enters the top of the tower and passes through the distribution system, it then travels by gravity downward. The next thing the water encounters is some type of media packing. There are various forms of media packing offered in the degasification industry, and each type can offer higher performance or have the ability to deter fouling. The selection of the type, size, and volume is where the “experience, engineering, and understanding of each application” comes into play.

To enhance and control the production and quality of seafood grown and harvested.

The industry increasingly focuses on constructing in-house aquaculture fish farms, commonly called aqua farming. The most popular species of aqua farming continue to be salmon, tilapia, catfish, and carp. Increased interest in the United States has developed aqua farming facilities in southern Florida with favorable climate and water conditions.

When considering several types of fish species to grow for harvest, it is important to remember the need to control the water quality. If the aqua farm is intended to utilize man-made tanks, they will depend upon a constant flow of incoming water. If the aqua farm focuses on salmon, the water quality and temperature play a major role in the operation's mortality rates and production yields.

Having water with too high of hydrogen sulfide, carbon dioxide, total Organic carbons, and even turbidity can increase mortality rates among the younger fish species and is especially critical to salmon.

Having high levels of metals

Such as Iron that is identified as either “ferric” (Fe-) or “ferrous” (FE+2) and is naturally occurring within the Florida waters and other parts of the US will cause significant damage to young salmon species because the metal accumulates within the gills of the fish causing suffocation. Other metals are also detrimental to fish, including copper, aluminum, arsenic, cadmium, chromium, Lead, manganese, and mercury, to name a few, and the water quality must be evaluated and tested in the early stages of design to anticipate the required types of process systems needed.

Water Treatment

When planning and designing a man made on land aquaculture or pisciculture facility.

The most important key element is the quality of the water. For operations developing in Florida or the Caribbean it is important to remember that water quality varies in Florida and other states in the US and typically requires some type of water treatment. For fresh and salt water land based farms that utilize tanks located inside of a building the water needs to be treated and pure from any naturally occurring contaminants such as hydrogen sulfide (H2S), iron (Fe+), and even carbon dioxide (CO2).

The most cost effective way to treat incoming water for aquaculture farming and remove hydrogen sulfide, iron, and lower carbon dioxide is the use of a “degasification” tower. A degasification tower or degasifier is a piece of process equipment. Degasifiers can also be referred to as a “decarbonator” or “air stripper” or even “aeration tower”. The degasification tower is a vertical column designed to remove certain types of contaminants by “stripping” the molecules of converted gases and expelling them from the water as a gas. The science is based upon “Henry’s Law” and it relies upon the disproportionate varying vapor pressures of gases.

If the incoming raw water contains levels of sulfides or hydrogen sulfide gases it is recommended to remove the hydrogen sulfide to improve the water quality and reduce the risk of the development and formation of bacteria that can thrive on the Sulfur. In addition hydrogen sulfide is corrosive and will cause harm to other components within the process if left untreated. It is important to adjust the pH of the raw feed water prior to degasification to ensure full conversion of the sulfides into hydrogen sulfide gas (H2S) to enable the degasification process to perform and remove up to 99.99% of the harmful contaminants without adding additional chemicals. This saves money and improves quality of the product!

DeLoach Industries made history in 1977 at the City of Cape Coral Florida water treatment plant with its large scale “degasification towers” connected to what was to become the first municipal water treatment facility in the United States to deploy the use of reverse osmosis on a large-scale production municipal treatment plant.

The Cape Coral water treatment plant for came online in 1977 and produced 3 million gallons of water per day (GPD) or 11.35 liters of purified and treated water utilizing the “reverse osmosis” process. By 1985 the plant had expanded as it kept up with growth to produce 15 million gallons per day making it at the time the world’s largest “reverse osmosis” water treatment plant facility.