How do Biological Scrubbers Work?
Biological Scrubbers (also called Bio-Trickling Filters) treat gaseous contaminants in an airstream by passing it through a bed of microorganisms that feed on the gaseous molecules, consuming the H2S and other compounds as food removing them from the airstream. These microorganisms (Thiobacillus genus) live on a high surface inorganic bed inside the dedicated vessel at a low pH. Because H2S is what they consume, this eliminates the need for continuous carbon replacement in carbon bed adsorbers or chemical consumption in chemical scrubbers.
Biofilters are similar but unique compared to soil bed filters. Biological Scrubbers use the same microbial activity as soil bed filters to remove H2S and other contaminants, but require only 10% of footprint of an equivalent soil bed filter. Additionally the process is inherently more stable, efficient and independent of weather conditions as the biological activity is contained inside the vessel where pH and nutrient levels can be controlled.
Small amounts of nutrients
Only small amounts of nutrients are needed in Armatec Biological Scrubbers for optimizing microorganism health. No oxidising chemicals are required, greatly reducing daily operating costs. The nutrient is typically a multi mineral garden fertilizer product, and can be minimized or eliminated when the fresh water stream contains sufficient nutrients. To keep the conditions optimum for the microorganisms, a small stream of fresh water must be continuously supplied to the biological scrubber sump, and excess water at approximately the same rate overflows to waste. This waste stream contains spent microorganisms, waste acid and any toxic byproducts formed. Recycled treated water from the wastewater treatment plant can be used as the fresh water source, as long as it does not contain any chlorine.