Groundwater treatment plants are vital for protecting the environment and human health during the construction and operation of Sydney’s rail and road tunnels. As network construction has expanded, groundwater containing a wide range of contaminants has been intercepted by tunnelling posing a risk to Sydney’s waterways.

Proactive collaboration between the NSW EPA and industry ensured contaminant risks were identified early and treatment plants designed, constructed and operated to effectively treat groundwater contaminated with legacy pollutants.

This paper examines how early engagement and communication of the EPA’s regulatory requirements with proponents and their consultants worked to enable the protection of Sydney’s waterways. Coupled with an innovative, pragmatic approach to regulating advanced technologies, it played a critical role in the adoption of advanced
groundwater treatment plant technology to produce high-quality effluent. This paper also quantifies some of the improvements in effluent quality, highlighting the contribution to restoring and maintaining the community’s uses and values of Sydney’s waterways.