Millions may be saved in waste water plant

Ratepayers may be spared millions of dollars in disposals costs at the Whangamata waste water plant.

Service delivery group manager John Whittle said the council is hoping it may not have to build a second storage pond for treated waste water in the forest, as originally required under the resource consent granted by Environment Waikato.

Since the consent was granted in May 2007, some geotechnical and other problems on the proposed site of the pond have been discovered. But another solution has been found which is “technically better” and which will meet all the environmental standards imposed by the original consent conditions, Mr Whittle said. If the new option is approved by Environment Waikato, it will save up to $5 million in expenditure – about $285 per TCDC ratepayer connected to a Council waste water scheme.

Mr Whittle said instead of building the second forest pond, the proposal is to use the former aeration pond at the treatment plant for storing treated waste water. The existing forest retention pond would also have its capacity increased by desludging and deepening it.

The need for a second pond would be further avoided because more areas in the forest, well within the bounds of the existing resource consent, have been identified as suitable for spray irrigation.

Mr Whittle said Council began discussing the potential change with the waste water working group earlier this year and met members again on Friday once TCDC Councillors confirmed they wanted staff to go ahead and seek approval for the change from Environment Waikato. Mr Whittle said most parties were very positive because there were no environmental impacts and because the cost savings to the community were so significant.

Meanwhile, good early operating results suggest there may be potential for further savings. The new plant is consistently producing effluent with nitrate levels much lower than expected. Fine-tuning of the plant is expected to drop nitrate levels further, Mr Whittle said.

As a result, TCDC is applying to Environment Waikato to delay building denitrification beds for 12 months just in case the beds are not needed at all. The denitrification beds help strip out nitrates prior to the waste water being spray irrigated. If it proves they are not necessary, Council could save a further $1.5 million in expenditure.

“It’s looking very, very good so far but we’re very aware that as yet, the plant hasn’t had to deal with a peak summer season,” Mr Whittle said. “All the signs are looking positive that the denitrification beds won’t be necessary, but we can’t guarantee it as yet.”