Filter media for
Bioscrubbers
Eliminate odour issues with high surface area media to maximise performance of chemical or biological odour treatment processes.
Media for Bioscrubbers
If the odour is caused by water soluble, biodegradable species like VOCs, a bioscrubber can be used.
In a biological scrubber, the contaminated gas is passed through a scrubbing column much like a chemical scrubber but the scrubbing liquid is water. Soluble species dissolve in the water which is then treated in a biological reactor (trickling filter, activated sludge etc) to remove the biodegradable contaminants. The water is then recycled through the scrubber.
The specific surface area is important but, because there is inevitably some biological growth on the media, high voidage is necessary to prevent blocking.
Media for Biofilters
Where odour-causing species are mostly organic, biological filtration has a proven track record.
The air passes through a bed of media on which a biomass grows. As the air flows upwards through the bed it encounters a variety of microorganisms. The specific population depends on the nature of the odour but will typically include sulphur oxidising bacteria for hydrogen sulphide and mercaptan removal, nitrifying bacteria for ammoniacal odours and heterotrophs for VFA degradation.
The media is continuously irrigated with water containing selected nutrients for optimum bacterial growth. The key to success is a high surface area for biomass growth combined with low pressure drop since the air flow is natural draught. Traditional media include wood chips, mussel shells, rocks, etc, but they require regular replacement. Warden’s media offers both high surface area and voidage but with high durability and life expectancy, no need for replacements.
Media for Wet Chemical Scrubbers
Where the odour is caused by water soluble species like ammonia, hydrogen sulphide and mercaptans, it can be easily destroyed by chemical scrubbing.
The contaminated air from process is collected and is blown upwards through a column filled with a packing media while a recirculated liquid phase flows in counter-current down the scrubber. The scrubbing solution, which is recirculated, is selected by chemistry: dilute acid for ammonia removal, dilute alkali for hydrogen sulphide and sodium hypochlorite for oxidizable organics like mercaptans. As the strength of the scrubbing solution falls over time, some is bled off and replaced with fresh to maintain the required concentration.
The packing media is there to maximise the surface area between the liquid and gas phases. The stripper diameter is determined by the gas flow and the packed height is determined by the concentration of contaminant in the inlet gas stream, the desired discharge concentration and the specific surface area of the packing.
What benefits do our filter media bring to trickling filter treatment processes?
- High specific surface area
- High voidage for low gas phase pressure drop, minimising fan power
- Excellent chemical resistance
- Durable and rugged