DELOACH BLOG

The water and wastewater industry has a constant need for dependable odor control systems that are reliable and effective. The most popular process types of scrubbers are biological and chemical scrubbers. Each is effective at treating and removing noxious odors that arise from hydrogen sulfide (H2S) and methane.

Chemical injection systems can include biological agents, hydrogen peroxide, or proprietary agents in addition to odor masking agents that do not react but rather cover up odors. Methane odors typically only appear in wastewater applications, but hydrogen sulfide can be present at either water or wastewater treatment facilities.

The common questions for deciding which type to use normally come down to two variables: “What will it cost to install and operate annually?” and “Are the odors caused by corrosive gases which need to be neutralized to prevent equipment damage, instead of just covering up the odorous smell?” In some cases, the remoteness of the location can also dictate the type of process to use. If the location is very remote with infrequent visits then it may make more sense to have a low-maintenance chemical masking or injection system installed. However, if the location does have frequent visits or an operator then the two previous rules normally govern the selection process. Quite often the selection is made improperly because of salesmanship or relationships to suppliers. This should be avoided at all times to prevent safety risks, damage to equipment, or high economical costs. Many times suppliers will offer discounted or even free equipment to secure chemical use contracts for a long-term commitment to chemical sales.

The first step is understanding the chemical analysis of the water you will treat.

Suppose this is an aeration process for iron (Fe) removal. In that case, it is vital to understand the water's concentration, pH, and alkalinity and the amount of calcium carbonate or other minerals present. Once you've determined that the water is suitable for the desired treatment process, you must choose equipment based on the water's volume and flow rate. Remember that water treatment equipment is not one-size-fits-all and is vitally important when selecting equipment to consider your water conditions.

If a tower's internals is damaged due to the weight of random pack media or fouled water and airflow, the pack media will become completely clogged, and water flow will be blocked. This will result in an expensive shutdown and repair. It is advised that routine service cleanings are carried out under a service contract.

For heavy fouling conditions, a slat tray media selection can save you both downtime and costs. Slat trays provide an anti-fouling benefit based upon the design intended to “shed” particulate as it is formed. They still need to be cleaned in heavy conditions, but far less often, and cleaning is more manageable. The tower process application requires high removal efficiency, then loose fill media may be the only choice unless a pretreatment tower with slat trays is installed in front of the process. Each application must be evaluated on its merits and reviewed for potential fouling and anticipated operating cost.

If fouled completely, loose fill, random pack media will block water flow and air and can, in some circumstances, become so heavy that the weight can damage the internals of a tower. This will cause a shutdown and more expenses to remove and repair. Routine service cleanings under a service contract are highly recommended.

Select the best type of odor control, fume, or air emission scrubber.

Industrial and municipal operations often face the challenges of capturing and treating air emissions from their process operations.  Off-gases, fumes, and odor emissions can be generated from the downstream process or material handling, such as those in the municipal wastewater industry.  However, industrial operations often generate fumes and off-gas air emissions from either the production of chemicals or the use and application of chemicals like acids and a wide range of other chemicals. These types of air emissions share a common need to be safely captured, contained, and treated to make the air steam safe before its release.  Some types of air streams create an odor that becomes a nuisance, as is typical with municipal waste that often releases Hydrogen Sulfide (H2S) and or Mercaptans (R-SH) gas during decomposition.  

Many variables should be considered

when beginning to choose the best type of air emission treatment process.  Within the industry, there are wet chemical scrubbers, dry absorbent scrubbers, biological scrubbers, and destructive type scrubbers such as catalytic and thermal oxidizers and flare technology that utilize heat to destroy and consume and oxidize certain types of off-gases. 

Each type of air emission process has its own parameters where it will perform optimally, and each type of scrubber has different levels of operating challenges and associated operating costs.  So how does one select the best process for each application?

At DeLoach Industries, we like to help customers with this evaluation process by completing a checklist guide, which helps guide the customer to the most economical and safe solution. Going through this process can help eliminate costly mistakes that may otherwise be overlooked.  Solutions are often selected by looking at the contamination only or by familiarity with the process.