The Chronicle was given a tour on Whanganui’s new wastewater treatment plant. Construction began on the facility last year and is expected to be complete by December. Video Bevan Conley
With Whanganui's wastewater treatment plant just over halfway through its construction phase the Chronicle was given a tour through the new facility.
The new facility is being built on the site of the old, massive treatment pond off Airport Rd.
There will be 28 million litres, around 11 Olympic-sized swimmingpools, coming in and being processed each day. From that, sludge will be turned into 10 tonnes of dried pellets which can be spread over land.
Whanganui District Council chief executive Kym Fell said he was pleased with progress on the $39million plant.
"Things are going really well," he said. "So far we're on time and we're also on budget which is really good."
About 50 or 60 people per day have been working on the construction of the new wastewater treatment plant.
Downer is the main contractor while six local sub-contractors and 26 local suppliers are also involved in the project.
The plant is expected to be up and running and in a commissioning phase by December and fully operational by July. Once operational, five to six staff will work at the plant which will be manned 24/7.
The plant's new anaerobic pond holds 57 million litres. Photo by Bevan Conley.
"It's a pretty impressive sight," Mr Fell said. "The benefits are going to be significant particularly on the marine coastal environment where currently we're sending everything out to sea untreated.
"The new plant will have multiple steps to be able to treat it to a quality that certainly meets our requirements - the resource consent requirements - and the environment out to sea will be by far superior."
The most striking thing about how the new plant will work is how many more steps will be involved in the treatment process. The treatment begins before it even gets to that side of the river.
Without all the jargon, it basically works like this:
Large objects are removed from the wastewater at the Beach Rd pump station before the wastewater is piped under the Whanganui River to the treatment plant inlet.
There it will go through a screening process to remove the grit before settling in a new pond.
The 57-million-litre anaerobic pond will have a floating steel cover to mitigate some of the environmental impacts.
The sludge that settles on the bottom of the pond and rest of the wastewater gets separated.
The water is moved to contact stabilisation tanks where the water is aerated in what is the main treatment phase.
The sludge is carried off to a de-watering and then dried into pellets which have 5 per cent water content.
The drying facility at the plant will have capacity to treat waste from other councils, potentially opening up a source revenue for the Whanganui District Council.
Lastly, the water goes through clarifiers and then is pumped through UV light treatment before going out to sea.
Photo Gallery
Image 1 of 13: The plant's new anaerobic pond holds 57 million litres.
