Balance Tank Bypass Pumping System at Richmond Water Treatment Plant

The Richmond Water Treatment Plant is a new domestic water supply treatment plant that serves the town of Richmond, the largest urban settlement in the Tasman district. The plant combines two bore water supplies which feed into it and delivers potable water to two reservoirs systems via a reticulated pipe network. The plant was constructed in 2014-2015 and commissioned in 2015.

A critical element of the treatment plant was a 1500 m3 tank which balances flows between the supply and demand of the plant. Shortly after commissioning, the tank had to be taken off-line to address some contamination and defect issues.

This paper describes the fast-track design process required and the implementation of an innovative and highly effective solution to the challenge of maintaining potable water supply services during outages of the balance tank.

This resulted in new controls and protection systems added to the infrastructure which creates an automated in-series pumping system that allows the balance tank to be taken out of service for extended periods of time. This can be achieved without any compromise to drinking water quality and quantity. Additionally, the solution had a fully work-shopped risk profile that was acceptable to the client, Tasman District Council.