Digesters 5&6

G&T were awarded the contract to construct two new 7,500m3 capacity Digesters at the ChCh Wastewater Treatment Plant. The Digesters are built half in and half out of the ground. The below ground portion of the tanks was constructed within a sheet piled cofferdam with well point dewatering used to control the high groundwater levels. The tank construction features insitu concrete floors, precast, post tensioned wall panels and a fixed steel roof. 

The larger precast wall panels weighed 38 tonne and required a 400 tonne crawler crane to place them. The steel roof's were fully prefabricated and painted in an adjoining tank. The completed roof's weighed 120 tonne and they were also placed using the large crawler crane. The work included all mechanical and electrical services as well as process design to commission the Digesters and transition from Mesophilic operation to Thermophilic.