Waiouru Sewage Treatment Plant Upgrade

The New Zealand Defence Force (NZDF) owns and operates a Wastewater Treatment Plant (WWTP) at Waiouru, which was originally built in 1957. The WWTP treats wastewater generated from the NZDF military base and from commercial and residential sources within the township, and discharges the treated wastewater (effluent) to a nearby stream. The treatment plant needed upgrading to comply with new discharge consent limits and PDP was engaged to undertake this work after assisting NZDF to obtain the new discharge consent.

The consenting, design and construction of the upgrade have posed a number of challenges, which have included balancing cultural and technical issues during the consenting phase, construction supervision at a remote site, working under climatic extremes, and the need to maintain the plant performance during construction, which has included refurbishment of existing unit processes. It has taken collaboration between all parties involved to achieve successful delivery of each stage of the project. 

Construction of the plant upgrade began in April 2013, finishing in December 2013. The construction included adding a dual tank sequencing batch reactor, Alum dosing for phosphorus removal and UV treatment. The upgrade also retrofitted existing sludge management facilities to provide improved sludge handling and dewatering. The plant was progressively commissioned throughout construction with the SBR tanks commissioned in December 2013. Fine tuning of each treatment process was undertaken in early 2014 and the treatment plant is now reliably providing a high quality effluent. PDP continues to work alongside NZDF, providing operational assistance to the plant operator via a SCADA link.