CASE STUDIES

UV Disinfection

NWL Fowberry WTW

The scope of works included the design and installation of a UV disinfection system suitable for potable water, compatible with the raw water parameters, sized to treat the full works design flows of 3.2Ml/d. The physical dimensions of the specified unit needed to allow for the installation of a bypass on the works outlet main. The UV unit was to be housed in an appropriate enclosure.

Our Client considered this project to be a high priority and it was a requirement that the works output be maintained throughout the installation. Any shutdown period had to be limited to less than 4 hours.

Sheers undertook site surveys, including manual excavation to expose and confirm the depth, size and material of construction of the main. A detailed design was then prepared.

The design options were reviewed and agreed and work commenced.
In this instance, the Client chose to carry out the final excavation and cutting in of the new pipework. Sheers utilised this shutdown window to complete the tie-in to the electrical services. In all, the works was shut down for a total of 80 minutes.

Sheers then proceeded to complete the works. This included the backfilling the excavation, preparing the concrete base and reinstating works from the excavation. The new bypass and existing main isolation and drain valves were cast in under the slab with valve boxes installed for access.

With the concrete suitably cured the partly fitted out UV Kiosk was lowered into place and the kiosk fitted snugly onto the base and installation of the UV Panel and Chamber commenced.

The installation and operation of the UV system was carried out without any modification or alteration to the existing Disinfection system. The hypochlorite dosing control system simply reduced hypo dose rate as a result of the UV unit providing primary disinfection and reducing the chlorine demand of the water. The Hypo system is still required to maintain a small Chlorine residual in the distribution system.

Berson UV UnitPre Fabricated UV PipeworkPre Fabricated UV Pipework in ExcavationPreparation of Kiosk BasePrepared UV Kiosk BaseUV Reactor Chamber InstalledUV Reactor Chamber Installed (2)Final Outcome