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Case Study: GRP Tank Covers - New Holland WwTW Odour Control Tank Covers

  • Odour Control Tank Covers
  • Odour Control Tank Covers
  • Odour Control Tank Covers
  • Odour Control Tank Covers
  • Odour Control Tank Covers
  • Odour Control Tank Covers

Industry Sector

Wastewater Treatment


NI Water


New Holland Wastewater Treatment ,Works, Lisburn, Northern Ireland


2 no. Odour Control Tank Covers to suit Concrete Sludge Holding Tanks within the Wastewater Treatment Plant.


2 no. GRP 13.6m diameter Self-Supporting 20° Conical Tank Covers

2 no. 1000mm2 hinged lockable access hatches with safety grilles
1 no. 150mm diameter air vent
1 no. 150mm diameter flang
1 no. 1300x1000mm Bespoke Lockable Wall Infill Cabinet


TES Ltd and Graham Construction were awarded the New Holland Wastewater Treatment Works improvement project in joint venture under the NI Water IF019 – Base Maintenance Phase 2 Scheme.

TES Ltd, the wastewater treatment main contractors of the scheme awarded Relinea the sub-contract to design, manufacture, and install 2 no. glass reinforced plastic (GRP) 13.6m diameter Odour Control Tank Covers within the plant, with the purpose of eliminating the odourous fumes radiating from the sludge holding tanks.


The odour control tank covers had to be installed without accessing the inside of the sludge holding tanks due to the active contents within.  This further enhanced the complications of the condensed installation time frame provided by TES for fitting the covers.

A highly resilient material was required for the formation of the tank covers to facilitate the endurance of the harsh chemical environment existing within the tanks.   This would ensure that the covers would not corrode and deteriorate over time causing costly replacement or maintenance issues.


Since the odour control tank covers could not be installed from accessing the inside of the tanks, Relinea proposed a self-supporting conical shaped tank cover design that could be manufactured in individual segments and easily installed by assembling the segments together onsite and crane lifting the entire constructed tank cover into position.

The proposed design was approved by TES and Relinea accordingly designed and manufactured the 13.6m diameter conical shaped self-supporting tank covers in 20° equal segments.  The tank covers were manufactured with a loading of 0.75kn/m² UDL in accordance with WIMES 8:05 and BS EN 1991-1 Standards.

The odour control tank covers were manufactured using corrosive and chemical resistant GRP.  Contrasting to the traditional highly corrosive steel tank cover system, the durability and preservation of the GRP covers was uncompromised despite the corrosive hydrogen sulphide fumes existing within the sludge holding tanks.

The installation proved to be challenging owing to the confined working space onsite designated for Relinea’s installation team to assemble the tank cover segments together besides the installation time constraints onsite.  Considering these obstacles, Relinea’s highly skilled and professional installation team completed the installation within the tightly scheduled time frame provided by TES and to the complete satisfaction of the client.