Wastewater overflow: Warning still in place at Sulphur Bay area

The wastewater that overflowed into the waterways at Rotorua's wastewater treatment plant was not raw sewage, says Rotorua Lakes Council acting water solutions director Stavros Michael. Photo Photo/Andrew Warner

Rotorua's wastewater treatment plant is back operating within capacity after a weather bomb caused a pond plant to overflow into Puarenga Stream.

But warning signage is still in place.

A warning was put in place yesterday afternoon for people to stay out of the water at Sulphur Bay, Lake Rotorua, following the spill.

More than 100mm of rain has fallen in the Rotorua district over the past 48 hours, following 88.2mm of rainfall last Tuesday and Wednesday.

A council spokeswoman said as results from water sample testing would not be available for a few days, the signage asking people not to go into the water in the Sulphur Bay area would remain in place until it got the all-clear.

She said the amount of treated wastewater entering the pond exceeded the capacity of pumps to pump it out.

"This is the first time such an overflow has occurred. [Saturday's] break in the weather provided the relief needed to get the situation under control. This was treated wastewater, diluted by rainwater and no public health warning was issued by Toi Te Ora - Public Health."

Rotorua Lakes Council acting water solutions director Stavros Michael said it was important people knew the wastewater that overflowed into the waterways was not raw sewage.

He said this was not something the council wanted to see happening.

"We'll undertake an investigation of our networks to understand why such a high level of infiltration has occurred."

He said the council may need to accelerate work that was already underway to assess capacity of the infrastructure.

'We will also investigate increasing the capacity of the holding pond at the treatment plant. The proposed upgrade of our treatment plant will increase our capacity to deal with situations like this but that's some time away so we want to have measures in place in the interim."