Lake Hawea's sewage treatment system will undergo work this
month to improve its wastewater results, which continue to
exceed resource consent conditions.
Wastewater readings taken from the oxidation ponds' discharge
trench are showing higher than permitted nitrogen and
At yesterday's Wanaka Community Board meeting, 3 Waters and
solid waste senior engineer Rob Darby explained the scheduled
work which aimed to mitigate the amount of nitrogen being
Semi-submerged monitoring balls would be used to track the
flow within the ponds and determine whether the sewage was
moving too quickly from the inlet to the outlet.
The work would also involve the installation of ''baffle
curtains'', which would create ''a bit of a maze, so the
sewage can not take a shortcut to the exit point'', Mr Darby
told the Otago Daily Times.
''It has to follow a path through the ponds to get maximum
treatment time in the ponds.''
At the board meeting, deputy mayor Lyal Cocks asked if the
desludging carried out in February last year had helped
wastewater results, as had been expected.
Council infrastructure engineer Nicola Greaves said pond
performance had not improved as much as was hoped and there
were still issues with nitrogen levels.
Mr Darby said the work was expected to cost nearly $25,000.