Background: Air scrubbers strip out contaminants from exhaust stacks and transfer the contaminants into an aquatic medium in order to allow sufficient treatment. The contaminants scrubbing procedure is conducted in a chamber that enables the contaminated air to pass through small water particles (fog) generated by a sprinkler (spry nozzles). The contaminated water flows over a biofilm surface area that encases microorganisms (bio-scrubber). The contaminants are used as carbon and energy sources (organic compounds) for the bacteria in the biofilm. Contamination decreases as the aquatic medium is circulated inside the air scrubber, and treated water is returned into the spray nozzles. The biodegradation rate is thus a crucial parameter for design. Bio-scrubbers are the most suitable systems for the treatment of highly water-soluble compounds. It is essential to adjust the F/M (food to microorganisms) ratio and to take the contaminant biodegradation rate into account, in order to avoid contaminant saturation within the aquatic medium and consequently contaminant trafficking reduction from the air into the water and increasing the contaminants emission/exhausting into the atmosphere

Method: BioCastle offers the use of an external bio-treatment unit/s that aims to increase the biodegradation rate to avoid saturation of water contaminants. This allows increasing the treatment yield capacity of the scrubber, under the condition that the existing system (air-scrubber) can provide support for an additional contaminant load mainly by stripping and dissolving capabilities to and within the aquatic medium. 

The external unit is aimed to act as an additive treatment to the existing bio-scrubber. Use of our patented SBP technology enables us to select the introduction culture type and to provide a sufficient culture amount according to a calculated F/M ratio. This enables us to provide a prediction for the expected additional contaminant removal rate contributed by the external unit/s.

Findings: Each 5 m3 external bio-reactor enhanced with SBP capsules enables increasing the treatment yield by 0.5 kg/h for organic solvents blends. The external bio-reactor enables increasing the treatment yield, without (in most cases) the need to upgrade the air-scrubber itself.

Process Flow Diagram