Odour control

The control of odours is a key concern for water operators particularly when the treatment site is near residential areas.  This has been a 'hot button' issue for the Environment Agency for many years now with considerable fines being levied against water companies that fail to comply with standards.  As such various odour control systems are now commonplace within the water industry.

The odour control systems that utilise our spray nozzles, can, broadly speaking, be broken down into two main categories - direct contact spray and scrubber systems.

Direct contact spray

These systems deploy a fine spray of odour controlling mist.  This directly interacts with odour-causing particles and eliminates them.  The nature of these systems necessitates a very fine spray distributed over a large area to maximise the contact with the odour causing particles.  As such air atomising nozzles or other types of misting nozzle need to be used.

One of the key challenges encountered when designing these odour control systems is distributing the required finely atomised sprays over potentially very large areas.  Air assisted nozzles can help with this distribution but often fans are deployed to help move the spray.

Air scrubbers

When the contaminated air can be gathered to a treatment point (i.e. the initial cause of the small pollution is contained) it can be passed through a scrubber system.  There are various designs of air scrubber but the most commonly deployed is a pack media tower.  A spray of reactive odour-controlling fluid is distributed over a media bed.  As it trickles though the media the gas flow (contaminated air) is passed up through the media bed at the same time.  The smell causing particles in the air react with the fluid and are eliminated.  The media bed serves to dramatically increase the contact time between the air and the reactant fluid.

The nozzles used for fluid distribution at the top of the media bed do not need to produce fine droplets as they do with direct contact odour control systems.  Instead the objective is to widely distribute the fluid over the top of the bed.  Often this needs to be done with very little headroom.  For this reason wide angle full cone nozzles are the most sensible choice.  The TF range of spiral nozzles offers very wide (up 170­°) distribution as well as having excellent clog resistance.  This makes it an ideal choice for many packed bed scrubber systems.