The upgrade of North Shore City’s wastewater treatment plant that treats 55 million litres of sewage a day continues, with $26 million being spent on the latest stage to make it more high-tech and less smelly.

Part of the upgrade involves German technology – known as cell lysis treatment – being used for the first time in New Zealand.

As well as reducing odours, this technology reduces the volume of bio-solids by 20 per cent so there is less to truck to landfill saving an estimated $400,000 a year. It also produces more methane that is used to help power the plant and reduce electricity costs.

Stage five of the upgrade includes two new primary sedimentation tanks and improvements to the plant's inlet.

With $87 million already invested in this project, it is already paying dividends with fewer complaints being received about odours and regular checks indicating our odour-busting innovations are working.

To be sure, we are conducting our bi-annual survey to find out what the neighbours think and smell and results will be made public next month.

Above: Stephen Gibbons gets surveyed by Mike Organ from URS, while overlooking Rosedale Treatment Plant.