Ravensdown: $40m upgrade to Napier fertiliser plant, 50m-high stack

These chimneys at the Ravensdown plant in Awatoto are set to go and be replaced by one bigger stack. Photo / Warren Buckland

Plans are afoot to topple three chimneys on a Napier landmark and replace them with a taller 50m stack.

The project is part of a $40 million investment into the Ravensdown fertiliser factory in Awatoto and nearby regional park and includes an overhaul of how water is discharged from the plant.

Ravensdown received consent from the Napier City Council last year to knock down three chimneys between 36m and 38m tall at its factory base and replace them with one stack roughly 14 storeys tall (50m).

The stack will connect to a new scrubber system, which removes harmful materials from the plant before air is discharged, as the old system is nearing the end of its life.

The fourth and tallest existing stack at 55m, which stands at the southern end of the site on what is known as the acid plant, will remain in place.

"The four existing stacks are a prominent feature and have been a local landmark for many years and are visible from many viewpoints in the area," a council document read.

A view of all four existing stacks at the fertiliser site. Photo / Warren Buckland

"The proposal will result in three of these four stacks being removed and replaced by the new 50m-high stack."

While consent has been granted for that part of the project, Ravensdown is seeking further approval from Hawke's Bay Regional Council around an overhaul of its water discharge system and other upgrades.

That resource consent application is currently before the Hawke's Bay Regional Council and is open for public submission until February 18.

"Under the current arrangement, stormwater and process water is discharged from
Ravensdown via a settling pond located at the southern boundary of the site," the proposal read.

"The pond discharges via two pumps through a stopbank to a drain that flows to the Tūtaekurī River/Waitangi Estuary."

Water is currently added to the settling pond from bores to provide dilution before discharge.

Under the proposal, Ravensdown would invest in a new system which would take that water from a brand new settling pond and spray it on to land owned by the company, behind the factory.

Artist image of the planned new 50m-tall stack. Photo / Supplied

In essence, it would divert most of the stormwater and treated water on to land.

The company owns about 17.5ha of land that is available for spray irrigation.

"Ravensdown accepts that there is a strong cultural and community preference for discharges to be directed to land rather than water wherever possible," the proposal read.

"When discharge to the land is not possible, it is proposed to preferentially discharge to the estuary three hours before and three hours after high tide to provide for enhanced dilution and flushing of contaminants."

Water would be discharged on dry land via a spray irrigation system and that option would only be unavailable when the land was saturated.

Infrastructure would be replaced and upgraded as part of the new discharge system.

The company is also planning to pay $630,000 for a restoration project of part of the nearby Waitangi Regional Park, which is owned by the regional council.

Before (left) and after (right) of the proposed wetlands upgrade at Waitangi Regional Park. Photo / Supplied

The upgrade will see two hectares of the regional park turned into a restored wetlands area.

When the wetlands are complete, they will be used on occasion to discharge treated water from the plant, according to the proposal.

The acid plant's converter is also set to receive an upgrade under the project.

Ravensdown works manager Andrew Torrens said the huge investment was about the long-term future of Ravensdown and protecting the environment.

"We strongly believe that the solution we are proposing is best for the environment but is also a sustainable investment for Ravensdown to make in our operations side here in Napier," he said.

"It is the right investment to make to enable that sustainable community model we are looking for."