There are three commonly used technologies for the prevention and control of odor gases:
1: chemical scrubbing
The chemical scrubbing treatment system consists of passing the gas through scrubbing towers where air/water/reagent contact takes place. In chemical scrubbing, an acidic or basic chemical solution is injected into the system from the top, passing through the flow of the gas, and is then recovered at the bottom of the tower for recovery and recirculation. The gaseous compounds are retained in the chemical solution which must be replaced periodically.
This technology has a high operating cost and a high risk associated because of the handling of this kind of chemicals.
2: filtration with solid adsorbents
There are different types of solid adsorbents for odor removal, the most common is activated carbon. The gas passes through tanks containing the adsorbent media. The adsorbent media and its ability to remove odorous gases can vary depending on:
- The porous structure of the base material (activated carbon, natural clays).
- The chemical impregnation of the agents that cause the adsorbent media to react with specific gaseous contaminants to retain them or convert them into non-odorous ones.
Activated carbon filtration is a technology with a low initial investment cost, which does not require qualified personnel for its operation, which makes its use extensive.
The installation of covers in different areas of the wastewater or sewage treatment plant (pretreatment, thickeners, sludge storage, decanter channels (1st and 2nd), allow to mitigate the dispersion of odorous gases and to channel the air flow towards a tank with adsorbent media that allows the filtration of odor causing compounds (H2S, ammonia, sulfides, mercaptans, VOCs).
BION offer solutions consisting of adsorbent media or chemical filter media (https://www.bioconservacion.com/chemical-filtration-media). These solutions include virgin activated carbon and other adsorbent chemical media that effectively remove odor gases generated in a WWTP even better and more efficiently than activated carbon solutions.
3: advanced biofiltration (biofilters)
The biofiltration deodorization process is based on the action of microorganisms capable of decomposing odorous compounds. They are effective when it is necessary to remove high concentrations of odor compounds or to treat large air flows. The operating cost is minimal. But microorganisms are sensitive to atmospheric conditions of temperature and relative humidity. Also need a constant supply to survive. It can be affected by process stoppages or decreases in the concentration of the compounds reaching the filter.
Each of these systems has its own characteristics, advantages and disadvantages. The most appropriate technology will depend, to a large extent, on the type of gaseous effluent to be treated.