Odour Abatement Device
The Mill-Pro Odab™ (Odour Abatement Device), is an activated carbon filter cartridge designed to absorb odours created in pressure and gravity sewer pipeline systems. Hydrogen Sulphide (H2S) is an unpleasant “rotten egg” odour that vents to atmosphere through manholes. The replaceable Odab cartridge contains a special media formulation comprised of activated carbon and other compounds that indicate with colour when the cartridge is exhausted. The media formulation maximises flow through the entire absorption bed, capturing H2S and related odours that are generated when raw sewer is exposed to air in pipelines and chambers.
The Odab is licensed from Inventive Resources Inc in the United States, where it has been in operation successfully in the US and other countries since 2010. The design includes patented expanding bellows, drains for surface water, non-return valves and other features that ensure the media is only exposed to peak flow H2S. Peak flow is a fraction of the typical exposure, this extends cartridge life 10x more than media constantly exposed to H2S.
Hydrogen Sulphide (H2S) and other Sewer gases are created when raw sewer reacts with the atmosphere (air), this can occur in both gravity pipelines that have a varying level of air above the sewer and in high points in pumped pressure rising mains where it vents through sewer air valves in valve chambers. H2S gas is deadly in confined spaces, highly flammable, explosive if contained, and unpleasant for the public when vented through manholes. Sealing a manhole simply multiplies the gas sending it to the next available outlet and creating significant safety risks.
The amount of H2S in any given sewer system is a function of: Air to liquid ratio, relative humidity, temperature, and dwell time, when air mixes with raw sewerage.
In typical gravity sewers, liquid volumes in the system are minimal late at night and high during early mornings and evenings. As the levels fall, fresh air is sucked into the sewers through manholes, this oxygen in the air reacts with the surface of the sewerage creating H2S gas. As drainage activity increases (for example in the mornings) sewer levels in pipes and chambers rise and these H2S gases are expelled out through manhole chambers, creating unpleasant odours at street level.
The Odab is designed to allow the manhole to safely vent treated odourless air, whilst capturing the hydrogen sulphide from that air through absorption in a replaceable activated carbon cartridge, which can be safely disposed of at a landfill once saturated.
For more information visit the MOE website here.
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