Air emissions from livestock housing systems are under increased scrutiny for strategies to reduce potentially harmful gases. Wet air scrubbers are one of the ways to remove pollutants from air being exhausted from mechanically ventilated buildings. Wet scrubbers use liquid to collect dust or particulate matter (PM) and absorb gases from the air by using a wet surface, spray system, or wet material bed. Particulate matter (PM) is a major air pollutant from animal production with significant impacts on human health and the environment. Effective PM control technologies are strongly needed. Some scrubbers use water for removing pollutants, while others use different types of acid or a base to shift the pH to absorb specific gases in the air.
Despite the widespread use of chemical, biological, and combined air scrubbing systems, there is still insufficient knowledge of process engineering aspects such as removal efficiency, energy design, and process control.
Wet scrubbers clean air by physically trapping PM on wet surfaces and absorbing gases into the liquid. In some cases, the gases react with chemicals in the liquid. Small liquid droplets are more effective because they have more surface area than fewer, larger droplets. Very small liquid droplets are difficult to remove from the airstream after they absorb or react with the gases.
Wet air scrubbers for animal housing generally are either acid scrubbers, bioscrubbers, or water-only scrubbers:
- Acid scrubbers trap alkaline material, such as ammonia, in a sulfuric acid solution that is circulated over a packed bed at a pH of 2 to 4. The ammonia removal efficiency tends to be over 90%, while the odor removal rate is around 30%;
- Bioscrubbers convert ammonia into nitrate and nitrite. They tend to use 8 to 10 times more water than acid scrubbers. The ammonia removal efficiency averages approximately 70%, and the odor removal efficiency averages 50%;
- Water-only scrubbers use water and not biomass or acid. This is less effective in ammonia scrubbing but still a viable choice.
At the moment a new generation of so-called “multi-pollutant scrubbers” is being developed and tested that not only removes ammonia but also aims for significant removal of odor and particulate matter from the air. Such multi-pollutant scrubbers usually consist of two or more scrubbing stages. However, it should be noted, that odor and dust removal are less effective than ammonia removal, at least for now. Multi-pollutant scrubbers offer a solution for large livestock operations to continue functioning close to residential zones and vulnerable ecosystems, although the expenses are viewed as considerable.
A new type of wet air scrubber, Multi-vortex wet air scrubber cleans air from gases, dust, vapors and other admixtures using water or other cleaning liquid.
Multi-vortex wet air scrubber produces the cleaning mist differently from other scrubber systems, which results in running costs that are much lower than for a common wet air scrubber. Multi-vortex wet air scrubber is the new type of wet air scrubber that saves water.
If you are interested in purchasing Multi-vortex wet air scrubber, please contact us at info@rdwd.tech
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