DELOACH BLOG

What is the best process for hydrogen sulfide treatment? Biological odor control Scrubber or a Chemical Scrubber?

Most industrial water treatment, municipalities, and private customers are responsible for water and wastewater treatment and often generate "hydrogen sulfide" off-gas odors. Professionals who either provide the design engineering or maintain the water or wastewater collection systems need to address and control "hydrogen sulfide" odors. They often find themselves in a situation where they must select what type of odor control system will perform for their customer or at their location. A chemical odor control scrubber may utilize "chlorine" or "caustic" as a scrubbing agent or just "caustic" alone. Typically, "acids" are not used when treating "hydrogen sulfide" gas, but "acid. " Acid is used when treating other types of off-gases such as ammonia. The application or process, including incorporating "artificial intelligence" into the machinery to provide more rapid responses to operators to predict maintenance and other operational functions—treating process air generated by either a "decarbonation" tower or a "degasification" tower for the removal of "carbon dioxide (CO2) or "hydrogen sulfide (H2S). It is important to understand the basics of either of the processes to allow the design professional to properly select the best type of "odor control" scrubber to utilize and make the decision to either select a chemical scrubber that uses "caustic" or "chlorine" or a biological scrubber for the treatment of the hydrogen sulfide that only requires the use of "caustic" to buffer the recirculation water. In other types of processes involving treatment, such as ion exchange, a design professional or owner must understand that the process may also produce an off-gas that requires treatment. "Ion exchange" can be used as a standalone treatment process to treat hard water utilized as a post-treatment process after reverse osmosis. Regardless of when "ion exchange" is utilized, we recommend removing the carbon dioxide (CO2) before the process to prevent the formation of carbonic "acid" and to extend and save the life of the Ion Exchange resin. It may also be necessary to adjust the pH of the water either pre or post-treatment by injecting either an "acid" solution when lowering the pH or injecting a "caustic" solution when raising the ph. It is important to remember that the efficiency of the process depends on proper pH control.

High pH and hydrogen sulfide will not convert or be removed by “degasification” and the “carbon dioxide” cannot be removed.

Opting for the appropriate odor control scrubber can lead to significant cost savings!

We have discussed the importance of understanding the source and concentration of an odor issue before selecting the type of treatment or odor control system. In addition to these critical items is the consideration of operating costs.

Many types of odor control systems work and remove odors, but selecting and designing a system that works efficiently and effectively without breaking the bank can be challenging.

When do you know if your decarbonation system needs service?

When a degasification tower or decarbonator becomes fouled, several indicators identify you may have a problem or that it's time to clean your system. If the efficiency of the degasifier has dropped, you will see an increased consumption rate of chemicals. If you remove less hydrogen sulfide gas from the degasifier, chlorine consumption will increase. When you increase the amount of chemical reaction occurring in the water, you will see an increase in the TSS levels and a drop in water quality. As the H2S reacts with chlorine, more solids will form and be present in the water, and the water quality will diminish.

Another indicator of a fouling condition is the pH adjustment in the Industrial Water Treatment industry. You are required to meet the set standards. As the performance of the tower drops, the removal of CO2 will also drop, leaving a higher pH level than may be desired. A quick inspection to check out the media bed should be performed. Also, do not forget to inspect the distribution system at the top of your tower and remember that all distribution systems are not alike, and inspecting the condition of each of them may require additional effort on your part. With a header lateral system, you need to inspect the distribution nozzles, but with a Weir or Tray type, you will need to check the amount of scale or fouling building up on the Weir edge or in the bottom of the pan. If the Weir edge becomes fouled unevenly, it will create "Channeling" of the water and increase the initial hydraulic load to a concentrated point on the media bed.

Protecting Your Pharmaceutical Water: Ensuring Quality and Efficiency in Water Treatment

In the pharmaceutical industry, the removal of dissolved gases from water is a critical step in the water treatment process. However, it is essential to select the appropriate method of removing these gases, as the wrong choice can have detrimental effects on vital process water equipment such as steam boilers and distillation columns. Failure to address high levels of carbon dioxide (CO2) in the water can lead to the formation of carbonic acid, which corrodes and damages both the steam boiler tubes and distillation columns. To mitigate these risks, the implementation of a degasification tower or "Degasifier" is crucial, as it effectively removes dissolved gases like hydrogen sulfide (H2S) and carbon dioxide (CO2) to acceptable levels below 7 parts per billion (ppb).

Utilizing a degasification tower offers a cost-effective solution to reduce and eliminate gases in the water stream. In comparison, alternative methods such as reverse osmosis (RO) membranes require additional steps, including pH adjustment, to achieve similar results. The conversion of carbon dioxide (CO2) into carbonates can result in increased membrane fouling and elevated capital costs for the RO system. By implementing a degasification system, businesses can achieve optimal performance, minimize membrane fouling, and benefit from cost savings in both capital and operational expenses.

The importance of removing Carbon Dioxide in the water!

Carbon dioxide exists naturally in nature as free CO2 and can be found in many water sources from lakes, streams, or other surface water bodies. Carbon dioxide occurs naturally in small amounts (about 0.04 percent) in the Earth's atmosphere. Monitoring CO2 levels in your water can be done through test kits or monitoring systems. When monitoring CO2 levels, it is important to note the concentration at which the monitoring needs to occur. Industrial level ion exchange systems should be monitored at a concentration typically 15–20 times greater than required for drinking water quality. Ion exchange systems used for high purity water production should be monitored at a concentration typically 40–50 times greater than what is required for drinking water quality. Due to carbon dioxide’s abundance and its role as the primary driver of climate change, there are concerns about increasing concentrations of this gas in the atmosphere. To reduce the amount of carbon dioxide in the atmosphere, people can reduce the amount of carbon dioxide released during energy production by using renewable energy sources and energy efficiency. Carbon dioxide can be captured and stored underground with carbon sequestration technologies.

Water treatment in the Caribbean poses unique challenges due to the specific characteristics of the region.

The Term referred to as “Degasification” or "Decarbonation" and how they work

Relates to the process of the removal of suspended gas or solids that are converted to a gas-based upon certain criteria during water filtration, treatment, membrane filtration, or attempting to adjust pH.   When removing (CO2) the process is often referred to as “Decarbonation”, when removing (H2S) the process is often referred to as “Degasification”. 

Degasification is the most economical method for

the removal of Hydrogen Sulfide (H2S), Carbon Dioxide (CO2), and Oxygen (0₂) can all be removed by “Degasification”.  The other variables are the total inlet water flow rate, the inlet feed temperature of the water, the ambient air temperature, the inlet concentrations that can be expressed as parts per billion (ppb), parts per million (ppm) or Mg/l, and the desired effluent removal levels also expressed in the same method.  It is also important to fully understand the actual application and the use of the water to determine how critical maintaining critical levels are and what impact variations will create for the final use.   Understanding these variables will aid you in the design of the system and any additional redundant systems needed to assure full compliance with standards.   

Maximizing and adjusting the pH of industrial water for degasification and decarbonation.

Do you need to remove or increase your reverse osmosis system's hydrogen sulfide removal efficiency?

The industrial water treatment market has many forms of water treatment processes. Most of us would agree that maintaining high water standards and quality requires using multiple treatment systems to achieve results.  Let’s face it, we do not win or get a “that a boy” when we design and build the best reverse osmosis system.

When we turn the brand-new water system on, the water has a "rotten egg odor." Yes, that is an embarrassing moment! 

The problem is we typically design around what we can see or read.  When was the last time you reviewed a water sample that provided details of how much-dissolved gas was in the water?  Most likely never.  A typical water treatment system may deploy reverse osmosis as the primary treatment method, and why true RO will remove particles that have size and weight (ions and molecules) typically defined as a certain size (micron), but RO does nothing to remove the dissolved gases that are already entrained within the water naturally or were created by adjusting the pH.  

Decarbonation is a critical process in water treatment, and understanding the impact of alkalinity is essential for its successful implementation.