Luxury pearl brand Paspaley has pressured an Australian resources company to rethink a controversial plan to discharge huge amounts of wastewater into Darwin Harbour, amid concerns about heavy metals contamination.

Key points:

  • TNG Limited recently revised its proposal to dump wastewater into Darwin Harbour
  • The aquaculture industry is among a group that raised concerns about the initial plans
  • The company says it will build a wastewater recycling plant instead

ASX-listed TNG Limited is planning to build a magnetite processing facility at Middle Arm on the harbour’s banks, to produce vanadium, titanium and iron products for export.

The project is awaiting a green light from the NT Environment Protection Authority (EPA) before a final ministerial decision. 

TNG wanted to dump up to 12 gigalitres of wastewater a year — equivalent to about 4,800 Olympic sized swimming pools — via a pipeline into the harbour, draft environmental impact assessment documents show.

But the company has recently backed away from the idea, promising to build a wastewater recycling plant instead that would remove any need for harbour discharge.

One of the objectors, Paspaley Pearls, told the environmental watchdog in February last year the original discharge plan would threaten the company’s shell breeding programs at the Darwin Aquaculture Centre and other harbour nursery sites, with the potential release of heavy metals and toxins.

“Paspaley is alarmed with the proposal,” the company’s chief operating officer Sam Buchanan said in a submission.

An aerial photo of Darwin Harbour, April 2021.

Recreational fishers and environment groups were also concerned about damage to the harbour.(

ABC News: Dane Hirst


“Sensitive early life stages are known to be vulnerable and susceptible to very low level toxins, especially heavy metals, as is true of many marine fauna.”

Dr Buchanan said contamination with even “trace or undetectable” toxic material would have an unacceptable “cumulative and chronic effect” on the harbour’s health.

“Paspaley is strongly of the view that the plant should not be approved based on the information provided to date,” he said in February.

Water security concerns

TNG also originally planned to draw an amount of water equal to 25 per cent of Darwin’s yearly consumption from the city’s supplies, according to a submission from several NT government departments.

The submission to the EPA urged TNG to look at the “fairness and equity” of using such high volumes of water.

An aerial shot of Darwin city and the harbour on a sunny day.

TNG originally planned to pump 12 gigalitres of wastewater from its minerals processing plant into Darwin Harbour.(

Supplied: HC Blechynden


“There is current community concern regarding low water levels in Darwin River Dam,” the submission said.

“This concern could be compounded by the significant amount of potable water required for this project relative to Darwin’s current consumption.”

The government departments also pushed TNG to justify the discharge of contaminants, saying it could push the catchment to its “carrying capacity” and limit future development.

TNG’s new plans to build a water recycling plant, and reduce water use by 65 per cent from previous predictions, follow pressure not just from Paspaley but also recreational fishers, environmental groups and the Larrakia Development Corporation.

Paspaley pearling boats docked in Darwin, April 2021.

Paspaley was concerned TNG’s original discharge proposal could impact its shell breeding program.(

ABC News: Dane Hirst


Amateur Fishermen’s Association NT chief executive David Ciaravolo said the change was a win for recreational fishers and other sustainable industries that rely on the harbour.

“The project quite simply could not have gone on with what they had initially proposed,” Mr Ciavarolo said.

Mr Ciavarolo described TNG as a “test case” for the Middle Arm industrial precinct, which the NT Government has heavily promoted as the site for a new petrochemicals manufacturing hub.

He said the NT government could do more to prevent “haphazard” development at Middle Arm and encourage global best practice.

A hand holds a baby barramundi in the Northern Territory, April 2021.

The aquaculture industry says even small amounts of heavy metals in harbour waters can be a threat.(

Supplied: Humpty Doo Barramundi


“There is really no excuse to have any other kind of development in Darwin Harbour,” Mr Ciavarolo said.

“What we’d love to see in the future is that companies start with their opening gambit already incorporating those principles.”

Humpty Doo Barramundi, which also uses the harbour as a nursery for its stock, told the ABC it was not opposed to “clean, healthy” development but that TNG’s original plan was concerning.

“Water security is a concern for every industry,” the company’s co-owner Tarun Richards said.

“We recycle our wastewater and reuse it — if we reuse it to grow food for people to eat, we couldn’t see why they couldn’t recycle or clean their water and reuse it.”

A portrait of Humpty Doo Barramundi co-owner Tarun Richards by Darwin Harbour

Humpty Doo Barramundi co-owner Tarun Richards is pleased TNG has revised its discharge plans.(

ABC News: Felicity James


Emissions would jump under proposal

TNG’s current proposal predicts its greenhouse gas emissions would be about 1.2 million tonnes a year and that this would be a 7.1 per cent increase above the NT’s overall annual emissions.

In its updated proposal — which is open for public comment — TNG said it had addressed the “main concerns” raised in public submissions about wastewater discharge and water use.

The company also agreed to develop a greenhouse gas management plan before commencing operations, including reviews every five years of energy efficiency and preparation of an offsets package.

But a report from Aurora Environmental, commissioned by TNG to advise on preparation of this plan, said the consultants found it “challenging” to provide advice because the NT had no clear policies on offsets.

A spokeswoman for the NT Environment Minister Eva Lawler said: “The Northern Territory government has an offsets framework which is currently being worked on to form a policy.”

In a statement to the ABC, TNG said it had no further information to provide about its processing facility.

Luxury brand pushes rethink on ‘alarming’ harbour wastewater plan
Source 1


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