But council staff changed their recommendation on Tuesday after assessing that the Lauder site might not be able to handle all of its sludge because of the capacity already committed to Wānaka’s waste and the potential savings for ratepayers were less than expected.
Instead, councillors voted to send the sludge to Winton landfill in Southland at a meeting on Wednesday.
Earlier this year, 20,000cu m of sludge was found to have built up in the Cromwell treatment ponds.
If not acted upon, the council said it would reduce the pond capacity and performance, which could trigger nitrogen limits and require “significantly more costly treatment upgrades”.
The council said the Lauder site operator had advised that it had already committed capacity to waste from Wānaka and there was a risk that some of the geobags from Cromwell might not meet requirements.
The cost of removing and transporting the Cromwell waste to Winton as well as pond desludging, was expected to be just over $3 million – which was more than a million dollars below the pre-tender estimate.
Council Three Waters general manager Julie Muir said the priority was having a clear, reliable plan in place.
“At this time, we’d rather have certainty than chase a saving that might not hold up,” she said.
“Getting the Cromwell ponds sorted before winter is the focus and landfill is the option we can rely on to get that done.”
Federated Farmers Otago president Anna Gillespie welcomed the Central Otago District Council’s decision.
“It’s heartening that councillors have heeded the anger and strong warnings from rural residents in Lauder and the wider Manuherekia catchment,” she said.
“The understandable motivation was to save ratepayers’ money in these tough times, but that cannot be at the expense of the environment and water quality in a sensitive catchment.
“Council officers warned of rural community fightback and potential for delays to the urgent programme of work to deal with sludge at both the Cromwell and Alexandra treatment plants.”
Gillespie said Federated Farmers still questioned the science and modelling behind the consent granted to spread effluent sludge from Wānaka at the former sheep and beef farm at Lauder.
The Otago Regional Council said the site had a regular monitoring and compliance programme underway and it did not rule out a potential review of the original resource consent.
– RNZ