A manufacturing facility cannot ignore the importance of odor control.

The smell from chemicals, vapors, and fumes can spread quickly in a small area. They cause discomfort to workers and pose health risks to them. In addition to that, excess vapors directly impact the efficiency of exhaust or natural ventilation systems. For example, an odor control scrubber tower is an additional layer in the ventilation system of a manufacturing plant or chemical processing facility that has issues with odors. These towers effectively remove noxious fumes and odors from ventilation exhaust streams using an activated carbon filter and an ionic air filter.

Reasons why you should consider installing an Odor Control Scrubber Tower :

Health & safety of workers.

Everyone working in an industrial environment, either directly or indirectly, is at risk of exposure to hazardous fumes and gases. At times, high concentrations of these gases may be emitted into the atmosphere in the form of unhealthy odors, putting the health and safety of the workers at risk. These gases may even be combustible in some cases, posing a significant threat to workers. The purpose of an odor control scrubber tower is to remove these gases from the contaminated air stream and help the workers stay safe. In addition, it reduces the risk of health issues such as nausea, headaches, loss of consciousness, allergy symptoms, dizziness, and many more. It also prevents workers from missing their daily performance targets due to sickness caused by toxic fumes.

Pro-environment step.

Although it is vital to protect the workers from exposure to harmful fumes, it is also essential to protect the environment. Odor control scrubbers are used in petrochemical refining, pharmaceutical, food & beverage, paper, mining, chemical, and pharmaceutical industries. Therefore, it is crucial to choose the right type of scrubber that suits your industry’s requirements. The right choice of equipment also protects the environment as it helps reduce operational costs and maintenance supervision. It also protects the environment because it produces minimal sludge and reduces the risk of corrosion.

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 a 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 shift over time. This is a normal behavior for all pH probes and is the reason why pH probes must be periodically calibrated.

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 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 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.

To enhance and balance the water quality

in aquaculture and pisciculture operations, the industry is recognizing the benefits from utilizing a type of water treatment called “Forced Draft Degasification” to remove CO2 (Carbon Dioxide) and H2S (Hydrogen Sulfide) gases and oxidize other elements such as Iron or Magnesium.

Removing these elements from the water process improves the quality of the water and aids in the balancing of the pH without the need for additional chemicals. This also reduces the risk of unnecessary and preventable loss of life to your aqua farming  project.  Keeping the ph at the proper level will enable a good healthy environment and will prevent further problems that may occur due to the ph is not kept in a stable state.

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.

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!

The Term Sour Gas

refers to any natural gas or other gas that contains high levels of hydrogen sulfide (H2S). The H2S is typically naturally occurring and found in deposits of natural gas and when there are concentrations above 5.7 milligrams per cubic meter or 4 milligrams per cubic meter when tested under standard temperature and pressure. At these levels the industry classifies the gas as “Sour.” Of course there are variations to this classification dependent upon agency an organization.

A Sour gas is not to be confused with an acidic gas 

although one could be both a sour gas is strictly defined by having large quantities of hydrogen sulfide and is usually accompanied by having mercaptans which adds to the foul smell and odor. The term is often used in the oil refinery business and when gases contain sour gas the process to remove the hydrogen sulfide and mercaptans is referred to as “Sweetening”. The most common method to “sweeten” and remove the sour gas is by processing the gas through an “amine process” which removes the harmful gas.

Caustic solution for Sodium hydroxide water treatment

There are many industries that require the use of a caustic scrubber which is considered a chemical scrubber and they range from the municipal industry, mining, semiconductor markets, pulp and paper and chemical refining.  There is a wide variety of industrial processes that generate noxious or corrosive off gases that require treatment and a comparison is made about biological Vs. chemical.  Often biological scrubbers have limitations due to concentrations, composition, or temperature of the contaminants and if the gas stream contains acid fumes then a biological scrubber is quickly ruled out.

The odor control selection is often fraught with choices of capital cost over operational cost and quite often comes down to familiarity from the designer or purchaser.  It is always a good idea to freshen up on the industrial odor control the do’s and don’t’s before selecting the final solution.  If the off gas source that needs to be treated is hydrogen sulfide (H2S) or some other type of gas stream produced by an acid or ammonia it will often require neutralization for human health reasons and to protect equipment or may be required to meet regulatory compliance. Caustic scrubbers may be either vertical or horizontal by design, but both utilize a packed media bed of either random packing or trays to allow the gas fumes to meet the recirculating caustic solution which then forces the reaction to occur.