Richmond valley Council has identified the need to undertake the replacement of the existing decant trough within the Extended Aeration Tank at its Casino Sewer Treatment Plant.

The Casino STP is owned and operated by Richmond valley Council and has two treatment streams. The majority of flow is first treated by a trickling filter process followed by an intermittently decanted extended aeration process. A portion of inflow is however diverted to the IDEA tank directly, typically when inflow is within the range of >87l/s to <165l/s. It is therefore imperative that works are undertaken in a fashion as to limit the downtime of the IDEA tank. The existing aeration system consists of approximately 14 banks of diffusers.

The existing decant trough system has inherent issues with the existing membranes splitting leading to undetectable solids carry over into the tertiary lagoon. One of the key drivers of this project is the ability to reduce solids carry over as well as increase efficiency within the operational cycle of the activated sludge process.

The objective of this tender is to source suitably qualified and experienced contractors that will have the capacity to perform the above mention decant replacement works. Councils expectation following the tender process is to have a realistic cost of this project as well as a preferred way forward.