What is it?
Hence, the conditions to use bioscrubbers are:
- the existence of the possibility to wash out the waste gas constituents;
- the washed-out constituents must be biodegradable under aerobic conditions.
Bioscrubbers are frequently inoculated with activated sludge, e.g. from a biological waste water treatment plant. Depending on the composition of the waste gas, the performance of the bioscrubber will only attain the desired level after some weeks of adaptation.
Inoculation with cultures prepared in fermenters is particularly applied to contaminants that contain sulphur (mercaptans, hydrogen sulphide, dimethyl sulphide, etc.) or chlorine (chlorinated methanes or ethanes).
Design, maintenance and efficiency
It is not suited for aliphatic hydrocarbons, aromatic hydrocarbons, ethers and halogenated hydrocarbons.
Application of bioscrubbers for odour removal can be found in:
- Cigarette industry: Odour concentration is reduced by approximately 5000 ouE/m3 to 200 – 300 ouE/m3
- Wastewater treatment plants
- Production of enzymes
- Production of aromas
- Rubber industry
- Production of polymers
- Processing of paint residues
Table 1 shows application limits and restrictions associated with bioscrubbing (adapted from EIPPCB, 2016, Table 3.185).
Table 1. Application limits and restrictions associated with bioscrubbing.
|Gas flow (Nm3/h)||1000-3000 Nm3/h per m2 of column surface|
|Pressure drop (mbar)||2-3|
|Sludge concentration||Maximum 15 g/l dry matter|
|Odour concentration (ouE/m3)||>10000|