Froud, Colin2, Letto, Daryl1, Webb, Derek1,
1BIOREM Technologies Inc., Guelph, Ontario, Canada 2CSO Tecknik Ltd, UK
(free)Permanent media biofilters have demonstrated odour removal efficiencies greater than 95% on a
variety of highly odorous wastewater treatment processes, including biosolids storage and
dewatering. Recently, biotrickling filters have emerged as a viable emission control solution for
select municipal wastewater applications. The removal efficiencies and the range of compounds
effectively treated with biotrickling filters tend to be more dynamic than other fixed film bioreactor
processes. Other odorous compound removal is somewhat unclear and biotrickling filtration as a
total odour control solution must be clearly defined data. As with biofiltration, biotrickling filtration
is a fixed film biological process used to treat odorous components of a waste air stream. The
biotrickling filter has a recirculating liquid solution that provides the developed biofilm with a
means of controlling pH, accumulation of metabolites, and provides the system with the required
nutrients. The efficiency of the technology is specific to the microbiology that is cultured in the
media.
The performance of biotrickling filters show equivalent or better performance on process air
streams with a wide range of H2S concentrations. Biotrickling filters treating an air stream
consisting only of H2S provides excellent total odour removal. The performance of biotrickling
filters of a highly odorous air streams consisting of a variety of odorous compounds, such as
volatile organic compounds (VOCs) and reduced sulphur compounds (RSC), show that
biotrickling filters do not provide a total odour control solution.
This paper will compare and contrast the differences between biotrickling and permanent media
biofiltration using published performance data and collected field data. A discussion of the
advantages and disadvantages of each technology for the given treatment process will identify
the framework to select the appropriate technology for the municipal wastewater application.
KEYWORDS
Biofilter, Biotrickling Filter, Municipal Wastewater Treatment, Odour Control
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