Negotiations about the possible dispersal of treated sewage
sludge on farms near Luggate is still ongoing between two
landowners and Queenstown Lakes District Council
QLDC solid waste manager Stefan Borowy was questioned on
Tuesday by members of the Wanaka Community Board, who wanted
updates on the council's sludge-spreading proposal.
Board member Dick Kane wanted more information about whether
the sludge would be hazardous, given it had killed worms
during a processing trial conducted by a Cromwell worm farm
Mr Borowy said the trial was conducted independently and
without any input from the QLDC.
"We supplied the sludge, but we do not have any control over
the trial whatsoever," he said.
Further research had been carried out by council staff, after
the Otago Daily Times highlighted the fatal effects an
introduced polymer was having on sludge-processing worms.
The polymer, introduced as a coagulate to firm up sloppy
sewage sludge for transport requirements, breaks down when
left exposed to the elements, Mr Borowy said.
A trial conducted in Palmerston North produced results which
showed the polymer broke down after three days outside, he
Mr Borowy's research findings are disputed by Cromwell
Wormworx operator Robbie Dick, who has told the ODT worms
were still reluctant to process the sewage sludge despite it
being exposed for up to eight days.
Mr Dick claims the artificial polymer is a harmful
"inorganic" substance to his worms.
He has also raised concerns about the possible effect of the
polymer if introduced to soil.
The QLDC will need to obtain resource consent before it can
carry out a sludge-dispersal project.