13 March 2006
Odour possible as the Christchurch Wastewater Treatment Plant is upgraded
Residents may notice some odour from the Christchurch Wastewater Treatment Plant during the two weeks following the shut
down next Monday (20 March) of one of the main trickling filters, integral to the treatment process, for a planned
upgrade.
Christchurch City Council’s City Water and Waste Unit Manager Mark Christison says the filter, the second to be
upgraded, is being shut down as part of an eight week operation to repair corroded concrete walls and install new
distributing arms in the 52m diameter tank. The new arms provide increased capacity to further improve the quality of
the city’s wastewater.
“With one of the trickling filters out of commission there is a risk of some odour as the biomass on the filter dies off
and is removed from the filter,” Mr Christison says.
Although the work is planned to take eight weeks to completed, it is expected that only the initial drying and flushing
of the filter during the first two weeks will cause any odour.
“During the last three months we have operated the plant in a way to reduce the amount of solids held in the filter so
there are less solids to be removed in the shut down process,” Mr Christison says.
“When the first filter was upgraded, early last year, there was a large amount of solids in that filter which caused
significant odour over a long period. This is not expected to be the case this time due to the efforts over the last
three months.”
The work on the second trickling filter is one of the last major items in the upgrade of the city’s treatment plant
which started in 1998 and is part of work by the Council to improve the quality of final effluent discharged from the
treatment plant. It is integral to improving the Estuary and coastal environment.
ENDS