Cheaper filtration option favoured

Affordability was the key word yesterday as Cromwell Community Board members considered two multimillion-dollar options for upgrading the town's wastewater treatment plant.

Either option would add a sizeable chunk to residents' annual rates bills.

It decided to seek resource consent from the Otago Regional Council (ORC) for a staged, $9 million system, the cheapest of the two options it had short-listed. The Central Otago District Council was granted an interim consent earlier this year to continue to discharge Cromwell wastewater into the Kawarau Arm of Lake Dunstan, but was told no further short-term consents would be approved. Dye-testing of the effluent plume in the Kawarau Arm in February highlighted an unacceptable risk to the environment and public health, so the board was forced to find a solution quickly. It asked for public submissions on two options. The first was an advanced biological treatment system costing $16.7 million. It would add $543 to each Cromwell ratepayer's annual wastewater rate from 2017, increasing each year and rising to an additional $1415 by 2052.

The second option - the one favoured by most submitters and the board - was for an enhanced filtration system costing $9 million, which would add $253 to the annual Cromwell wastewater rate from 2015, rising to an additional $1261 by 2052.

''I'm not as confident of getting a 35-year consent [from the ORC] with that option but it is seen as the best value for money,'' council capital works programme manager Peter Greenwood said.

About 55% of the 115 submitters supported that option, while 35% were in favour of the more expensive option, which was more likely to get a 35-year consent.

The cheaper option resolved the public health ''bugs in the lake'' issue by 2016, board chairman Neil Gillespie said. Mr Greenwood said about 12 submitters favoured worm-based wastewater treatment. Board member Helen Hucklebridge said the board had a huge responsibility to the people in the town.

''Whatever we do today will have an ongoing effect on their pockets and their rates. I don't think people can afford option 1, there isn't enough money in their back pockets ... Option 2 is more affordable,'' she said.

Fellow board member Gordon Stewart said the more expensive option would add $500 on to each rates bill from 2017 and ''that's a very significant amount on top of a $2000 rates bill''.

Mr Greenwood said the Victoria Flats landfill was ''the last option'' and the most expensive one for sludge disposal. The Queenstown Lakes District Council was disposing of sludge on its own land ''and we're looking at following their lead''.

lynda.van.kempen@odt.co.nz