Huge mounds of biosolid sludge stored near Wanaka. Photo by
Testing a stockpile of biosolids at Wanaka's
decommissioned wastewater scheme in Ballantyne Rd has been
completed by the Queenstown Lakes District Council.
Council representatives will meet Otago Regional Council
staff to discuss the next move in the planned disposal of the
8170cu m of stockpiled biosolids, Wanaka Community Board
members have been told.
Council Wanaka project manager Rob Darby told the board the
tests showed the biosolids were similar in quality and
nitrogen richness to a high-quality agricultural fertiliser.
"Essentially, [the biosolids] are a very good source of
The material is the remnant of wastewater and sewage sludge
from the drained oxidation ponds at the decommissioned
Ballantyne Rd site - Wanaka's former wastewater facility
before Project Pure became operational.
Mr Darby said the solids had been stockpiled in large mounds,
covered with tarpaulins, and had sat "maturing" for more than
12 months at the Ballantyne Rd site.
The council wanted to carry out a "one-off" disposal of the
biosolids by dispersing the product on a 100ha farm also on
Ballantyne Rd. However, the council needed to find out
whether the dispersal would need an ORC resource consent or
be subject to conditions, he said.
Disposing of the biosolids from the decommissioned oxidation
ponds was not "in any way related" to the council's Project
Pure sludge-testing, Mr Darby said.
He rejected a suggestion the Ballantyne Rd project was a
potential trial run of disposing biosolids to land, such as
the council had indicated it wanted to do with sludge
produced at the $21.5 million Project Pure plant.
The alternative way of disposing of the more than 8000cu m -
the equivalent of about 267 shipping containers - was to
landfill, he said.
"That is not really a viable option because it is so
incredibly expensive. Essentially, we have a fantastic
agricultural resource here... it is a fairly common practice
to dispose of it [to land]," Mr Darby said.