Iwi’s alarm over extra sewerage
Thousands of extra litres of treated sewage is being poured into the sea off South Taranaki after months of rain helped to fill Hawera’s waste water treatment plant and ponds to the brim.
The South Taranaki District council increased its pumping rate through its marine outfall, nearly two kilometres off the coast, by a third this week to reduce the load on its storage ponds, engineering services manager Brent Manning said.
The extra load came from water getting into the sewer network from outside, not from more waste being produced.
By increasing the amount being discharged, the level in the ponds could be lowered so they had the capacity to take in extra water if more storms brought heavy rain.
‘‘We expect this to be a one-off,’’ Manning said.
The council and Fonterra use a two-kilometre marine outfall near the dairy giant’s Whareroa facility.
This week the council will increase the flow from their consented 12,000 cubic metres a day to 16,800 cubic metres a day.
However, the combined marine outflow consent limit will not be exceeded because Fonterra was in lower production mode.
Manning said the total combined consented amount was 42,000 cubic metres a day. STDC’s share of this was 12,000 cubic metres per day.
‘‘We exceeded our portion by 3,000 cubic metres yesterday. The extra volume is basically rain- water so while the treated wastewater being pumped out is an increase in volume, it is highly diluted and therefore should not have any impact on the marine environment that differs from our normal discharge.’’
The move has upset Te Runanga o Ngati Ruanui. Chairman Haimona Maruera Jnr said the iwi was deeply concerned by the vulnerability of the plant during bouts of heavy rain and the lack of a timely warning system.
Te Runanga o Ngati Ruanui Trust kaiarataki Debbie NgarewaPacker said the move highlighted a significant flaw in the system.
‘‘As we move into winter, heavy rain and wind is only going to increase and we need a guarantee from this council that the public will not be put at risk again,’’ she said.
‘‘We also understand extra monitoring is being undertaken in the area, and we need assurances that beaches and food gathering practices remain safe.’’
Manning said the council had requested a meeting with Ngati Ruanui and Nga Ruahine representatives to discuss the situation.
They emailed the iwi advising them of the change on Friday, and were in regular contact, he said.
‘‘I understand and share their concern about the increase. It is a preventative, protective measure to avoid the possibility of the ponds actually overflowing, to provide a buffer.
‘‘With climate change these sorts of events can be expected to arise more frequently and it is something we have to incorporate into our long-term planning.’’