Waitara Outfall Refurbishment Project Pigging Investigations

The Waitara outfall was installed in 1978 and was damaged during construction. It discharges treated wastes from the township of Waitara and several industries in the area. It leaks at several locations along its length. Free spans have occurred removing external support from the pipe. The performance of the diffuser does not meet statutory discharge requirements. A study commissioned in November 1988 identified that the outfall could be refurbished by inserting an HDPE liner pipe throughout the length of the pipeline. This with stability measures could effectively extend the design life of the outfall by 25 years at less than the capital cost of a new outfall. A pigging programme was devised to check the internal condition of the outfall and the feasibility of installing the liner pipe. This paper describes the preparations for and implementation of the pigging programme in 1989.