Odour control is a key component of STEP. A centralized odour extraction approach was initially recommended and validated through detailed modelling. However, the client required greater certainty regarding the volumes and movement of air within the tunnel and link sewers. Physical modelling was conducted to quantify air entrainment values at drop structures and further evaluate centralized versus regional odour extraction system approaches. As an outcome, a regional odour extraction system is implemented at tunnel work shaft WS-4 and shaft WS-7, with a two-stage treatment consisting of bio-trickling filters followed by carbon polishing.
Encardio-rite was awarded complete monitoring works of the project. It provided supply & installation of geotechnical/ geodetic instruments, monitoring, surveying, and bi-weekly reporting with evaluation & interpretations. Geotechnical and geodetic instruments were installed in diaphragm walls and soil to provide settlement, deflection and deformation data for the verification of the initial design of permanent structures and temporary works supporting the excavation.