Innovative Ventilation at Purton WTW

Air Technology Systems Ltd have designed and installed an innovative, energy saving, ventilation and climate control system to serve the control and UV rooms at Purton Water Treatment Works.

Client – Wastewater Organisation

Project Scope & Objectives

The initial specification required the removal of excess heat from the MCC Room and a mercury vapour exhaust system in the UV plant room.


Air is exhausted from the MCC by a range of grilles positioned adjacent to the discharge louvres on the MCC housing and transported via a range of galvanised ductwork. Run and assist fan sets have been included as this room can overheat quickly throughout the year.

The run fan would either send the air to outside (in high summer conditions) or to the UV room (when heat is required), thereby providing free heat at various times. The air will be recirculated to the UV room via our air induction system.

Our Industrial Ventilation System is designed to give a high mixing ratio within the room and ensure that any pockets of gas are quickly diluted, giving an even condition throughout the room. The System works in conjunction with the mercury extract system ensuring that the ‘push & pull’ effect significantly increases the ventilation efficiency. This also reduces the propensity for condensation within the room.

Fresh air is naturally drawn into the MCC via two wall mounted louvres, with open/close dampers, however in hot months the temperature of the UV room will be cooler than the outside air temperature, so we designed the system to recirculate cooler air from the main UV room when appropriate.

The main UV room will generally be a lower temperature as it is below ground and has cool water flowing through it. The air from this room will be recirculated when it is at a lower temperature than the outside air. There is a louvre with open/close dampers mounted within the internal wall for the occasions when the air is being transferred from the UV room. We are therefore taking full effect of the free cooling available from this area.

Within the main UV Plant Room, we allowed for louvres to be provided without motorised dampers, to allow natural exhaust ventilation when air from the MCC is being discharged into the UV room. These louvres will also allow air into the area on the odd occasion when the exhaust extract is on and all the air from the MCC is discharged to atmosphere.

An emergency mercury vapour exhaust system is included for the potential occasion when a lamp may be broken in transit within the room or when the lamps are being changed. This discharges to atmosphere.

Innovative Ventilation at Purton
Ventilation system