Typical Applications Include
Applications of high concentrations of H2S mercaptans and other waste defined emissions
Odour control for buffer, sludge, sewage and pasteuriser vessel venting and other venting with high H2S concentrations.
High humidity concentration extracts from manufacturing processes
Concentrated extracts from processes, including with high humidity.
Venting from tanks and storage units on waste sites and effluent plants
Prefiltering of highly loaded ventilation extracts.
Biofilters - dispelling the myths:
There is a history of poor design and installation of Biofilters, particularly in the waste industry, and as a consequence they can be considered inadequate for emission control. This is incorrect and we can help explain where they are appropriate.
These issues have mainly resulted from poor application, inadequate design, and a failure to carry out ongoing servicing. The below table highlights some of these issues and how they can be resolved.
|CHALLENGE||ISSUE WITH APPLICATION OF BIOFILTER||SOLUTION|
|Stringent control of odours or emissions on the process - <1000ou/m3 for example||Biofilters are less efficient than other technologies so will not necessarily reach this level of control. In addition, they release a mild odour from the media bed.||A secondary filter, such as a secondary carbon polishing filter, can be required for additional filtration.
|Emmission contaminant contains chemicals which kill biofilm||Biofilters have a ‘living’ media bed and are not suited to substances which are poisonous, or inorganic chemicals.||Use alternative abatement technology for these applications|
|Woodchip or other short-life material used on media bed||Biofiltering is an active process and degenerates beds such as woodchip. Typically woodchip will last around 12 months.||Use Pumice stone or Coir.|
|Open Top biofilter||These have multiple issues as detailed below but the largest problem is the protection of the bed.||Open-top biofilters do not maintain performance and should be covered to protect from weather,
|Inadequate irrigation||A biofilter should have irrigation covering the complete surface / overlapping. Open top biofilters do not have this so typically struggle with dry areas of the bed and subsequent emission bypass.||Used close top biofilters with correct overlapping irrigation|
|Incorrect distribution of air across the bed causing tracking||If the airflow is not spread correctly across the bed, the air will not have sufficient contact time on the media bed to remove emissions.||The air should be ducted across the filter media bed for correct distribution to ensure correct dwell times.|
|Poor ongoing maintenance, sometimes due to systems that are very difficult to service||Design of unit, and operator neglect.||Ensure good access, and that specified maintenance regime is maintained. Good supplier training is vital.|