Taranaki is running out of places to dispose of its drilling waste from oil and gas operations.
Five out of the 12 landfarms in the region have stopped taking waste and the rest are expected to fill up in a year or two, as dozens of new wells are drilled, according to the Taranaki Regional Council.
Landfarming involves spreading drilling cuttings across marginal land where the microbial population in the soil breaks down the waste and new pasture is sown on top.
Fonterra announced in June it would stop collecting milk from new landfarms, citing the high costs for testing for petrochemical contaminants.
Just when the landfarms reached capacity would depend on the rate of drilling activity in the next year or two, council director of environmental quality Gary Bedford said.
"It might be a year or two, but it certainly won't be a decade.
"We do know things are ramping up, so the issue of ensuring there is long-term capacity is one we need to be thinking about now rather than later."
When the Taranaki Daily News spoke to Tag Oil chief operations officer Drew Cadenhead at a media tour of oil and gas operations in the region a few weeks ago, he said there was definitely no concern about running out of landfarming space in Taranaki.
"We will never run out of space here and have to worry about that," he said.
Mr Bedford said the council would consider the option of dedicated landfarms, where waste could be spread more than once, if someone offered land. "The main point of interest for us would be whether repeated applications would lead to an unacceptable accumulation of the heavy metals. The hydrocarbons break down, heavy metals are present at very low levels."
The level of heavy metals in drilling muds in New Zealand were not high enough to be of concern in a one-off application but repeated application would require careful monitoring.
Landfarms could potentially operate on dry-stock farms where the property would subsequently return value to the farmer, but these tended to be on steeper land, he said.
"You wouldn't want to put a landfarm on a steep property where there is an increased risk of runoff.
Some cropping land in Taranaki could also be used for landfarming, although there was the potential issue of consumer perception as with Fonterra. Mr Bedford said elements of the drilling mud such as bentonite could be recycled and used again, while rock cuttings could be turned into bricks and synthetic-based muds could be incorporated into road tarseal.
A less favourable alternative was to send the mud to a landfill because it was a waste of landfill capacity.
"While it is a safe option and environmentally sound, it's also a very expensive option utilising a resource which could be better used for other things."
- © Fairfax NZ News
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