Whanganui tannery pulls chrome out of wastewater

Whanganui company Tasman Tanning will shortly commission a $1.8 million filter plant that will not only benefit the environment, but may also save ratepayers money.

The new plant, which will remove chrome from Tasman's wastewater, is almost fully functional and undergoing tests.

Removing chrome from the Heads Road tannery's wastewater will reduce the toxicity of dried sludge produced by the Whanganui wastewater treatment plant.

Without toxic elements, the sludge can be sold as fertiliser; with toxic elements it has to be trucked to a landfill in Waikato for disposal which is an extra cost.

The factory's technical manager Craig Thiele said the company had decided to take responsibility for its chrome waste, and there had been no pressure from Whanganui District Council, which operates the city's wastewater treatement plant.

Installing the chrome recovery plant was just one part of being environmentally responsible, Thiele said.

Tasman Tanning also undertakes energy auditing and minimises waste. It's able to sell some tannery by-products, such as fat and split material that's used in food casings and medical supplies.

Chromium is the main ingredient in the chemical tanning process — it gives tanned hides their blueish colour.

It will cost the company to run the chrome recovery plant, but it will make a small gain by being able to reuse the chrome.

The chrome-free wastewater will go through the city treatment plant and the council will charge Tasman and other industries for treating their waste.

Thiele said fees had been decided in negotiation — "We have worked closely with the council and we have reached a mutually agreeable level.

"We have always been concerned about cost, and it's expensive, but we understand it's necessary to have this plant and we want to be part of it."

Tasman Tanning's wastewater is 5 per cent of the volume going into the treatment plant, but it contains animal remnants and makes for about 25 per cent of the plant's biological oxygen demand.

Waste going into the treatment plant used to be measured four times a year, for 10 days each time. With the new plant on Airport Road it's measured continuously.

Tasman Tanning — which has between 250 and 280 staff — processes hides for meat company Anzco, about a third of New Zealand's total.

Privately-owned across three Whanganui families, it is the last major producer of finished leather in Australasia. Thiele said the company exported 98 per cent of its product.

The leather is used to cover car and aeroplane seats, and for furniture and footwear, with Range Rover, Air New Zealand and Blundstone among brands that use it.