At the design stage, United Utilities, which is responsible for operating the system, commissioned ACWA to assess the nature and volume of air from discharge points and establish the requirement for covers, vents and hoods to collect and direct odours, via a new ductwork system, to the base of the chemical scrubbing process.
In operation, odorous vents from the bio-filter, sludge tanks and other stages of the effluent treatment process are conveyed to the scrubbing system by two in-line fans. Within the packed tower, odour is removed from the waste gases by scrubbing
with sodium bicarbonate
and sodium hypochlorite.
The exhaust air entering the base of the scrubber passes upwards through random plastic packing material, which provides a large surface area to allow the mass transfer of contaminants into the scrubbing liquor as it flows downwards to the base of the scrubber.
The open structure of the packing material minimises the pressure drop of air passing through the scrubber and prevents solid deposition.
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