Mayor Phil Mauger said on Monday staff are working on a plan to reduce the amount of wastewater going into the ponds by instead diverting it straight to the ocean outfall pipe off the eastern coast.
Mauger said the wastewater would be partially treated and chlorine added to ensure bacteria levels were safe when it reached the ocean.
Cooler temperatures and high levels of rain at the ponds have also reduced the oxygen and algae levels, which had been causing the ongoing smell to worsen.
Mauger said the council has been in discussions with Environment Canterbury and mana whenua about finding an interim solution.
“Because the wastewater treatment plant has been running on a knife-edge since the fire, the ponds have been overloaded and are now in poor health,” Mauger said.
“We can’t sit back and expect conditions to improve on their own."
ECan issued the council with an abatement notice last week for failing to provide an adequate plan to address the stench coming from the fire-damaged plant in Bromley.
The city council was given just over two weeks to come up with an action plan to mitigate the smell.
“Anyone who lives nearby knows the odour issues have become more intense, and we’ve been looking at all ways to help alleviate the stench.
“Reducing the amount of wastewater entering the ponds will take the load off, give them space to recover, and – most importantly – address the current odour.
“If we can reduce how much wastewater is going into them, it will help stabilise pond conditions while the longer-term rebuild of our new treatment plant continues.”
Mauger says the approach would also provide extra resilience across the treatment system through construction of the new activated sludge reactor and essential maintenance on one of the plant’s clarifiers.
The wastewater diverted to the outfall would be partially treated, and the council would add chlorine to ensure bacteria levels are safe before it reaches the ocean.
There are a number of elements to work through to get this up and running. Staff are developing a plan as quickly as possible and will keep residents updated as this plan progresses.
Mauger said the council will continue to look at further actions to improve pond health and reduce odour.
