Keeping on top of 25 million litres of sewerage

03 June 2021

Did you ever wonder where the water goes when you flush your loo?

Processing wastewater or sewage  in our water, and making sure it’s treated to the highest possible standard, is the job of the 19-strong team at NPDC’s Wastewater Treatment Plant (WWTP) in New Plymouth.

Every day about 25 million litres of sewage passes through 630km of pipes to reach the WWTP. Once it arrives at the Rifle Range Road plant from around the District, it’s rigorously treated and comes out well within our resource consent requirements for the treated water to be discharged out the marine outfall into the Tasman Sea.

At the heart of the operation is NPDC’s Laboratory Coordinator Cath Yateman who’s proud of the plant’s stringent processes, independently accredited by International Accreditation New Zealand (IANZ) 

“We’re at the forefront of keeping our residents safe by the daily testing of millions of litres of sewage to make sure we can continue to swim safely in our rivers and gather kaimoana. The quality of the water leaving the plant is among the cleanest in New Zealand and we work hard with all our partners to keep it that way,” she says.

In Cath’s 10 years at the NPDC plant, no two days have ever been the same. There’s constant rigorous testing to ensure our wastewater is being treated to the highest possible standards and on top of that, other projects to factor in. For example, work is already underway on a $37m project to upgrade the plant’s Thermal Dryer and significantly reduce the carbon footprint of running the facility by 25% to 40%. The Dryer will run on a hydrogen/natural gas blend to produce the Bioboost® fertiliser and reduce sludge going to landfill.

NPDC collects and treats sewage from urban areas of New Plymouth, Bell Block, Waitara, Inglewood and Ōākura and returns clean water to the environment, as per central government environmental policies and guidelines.

The Wastewater Treatment plant was built in 1984, and reuses 500,000 litres of treated effluent every day to run its operations, instead of using regular drinking water.

 
Cath Yateman