Opinion divided over Mullumbimby sewer trial

Paul Bibby

Byron Council’s decision to spend tens of thousands of dollars on a low-pressure sewerage system trial in Mullumbimby has produced an angry response from residents who say it flies in the face of expert advice and common sense.

But the council says the low-pressure system has been used very effectively in New Brighton and offers the best value for money.

The council voted in favour of the 20-house trial at its last meeting on June 21 as part of a $500,000 project to address the chronic issues of inflow and infiltration into the sewerage system in Mullumbimby.

Unlike the existing gravity-based system currently being used, low-pressure sewers use a small pump station located at each house to move wastewater through.

Data gathering

The Mullumbimby trial would also involve gathering data from each house about precisely how much sewage is produced each day.

Proponents of the trial say this would allow Council to get the clearest indication yet of how much water is getting into the town’s aging, earthenware sewers.

But some locals living in and around Mullumbimby strongly oppose the trial and are calling on the council to abandon it and undertake a proper comparative analysis of the different possible solutions.

Resident Patricia Warren said that this type of comparative study had been undertaken by Council staff prior to introducing a low-pressure sewer system at New Brighton, and that they had recommended against pursuing this option.

‘The report concluded that a vacuum system was the best option,’ Ms Warren said.

‘Instead, a low-pressure pump system was installed.

‘…Property owners [in New Brighton] have been unaware of electricity charges being connected to their power bills and a number of pumps have had to be replaced within what would otherwise be considered their life expectancy….’

Another Council report, June 2010 Final Project Review of the Mullumbimby Sewerage System, also recommended against implementing a low-pressure system.

‘The retrofitting of a low-pressure pumping system (LPPS) to the Mullumbimby sewerage reticulation system would have a high capital cost and will not eliminate stormwater inflow,’ the report states.

Alan Dickens, a member of the council’s Waste Water and Sewerage Advisory Committee (WWSAC), said that when the group last met there had been general agreement that a comparative study should be undertaken prior to any trial.

However, he says that councillors were instead led to believe that the committee had recommended the trial go ahead and, on this basis, had given it the green light at the most recent meeting.

‘That was not the agreed position of the committee,’ he said.

He is also concerned the trial will pave the way for a low-pressure system to be introduced throughout the entire town.

Council responds

But the council’s director of Infrastructure Services Phil Holloway, said that ‘no firm decision’ had been made on the implementation of the program.

He also denied any changes were made to the minutes from the WWSAC meeting.

‘The minutes represented to the council are as per the adopted Waste Water and Sewerage Advisory Committee minutes… which were circulated to members in draft form after the meeting,’ Mr Holloway said.

In response to the argument that Council was ignoring its own reports into low-pressure sewerage systems, Mr Holloway said that while one Council report had found the vacuum collection system was a ‘marginally’ better option, it was ‘not the cheapest option compared to the three other systems being evaluated’.

Valuable information

‘Byron Shire Council was one of the first utilities in Australia to adopt the use of the low-pressure sewer technology (in New Brighton) and it has been very successful and reliable,’ he said.

Another member of the WWSAC, Duncan Dey, said he was also in favour of the trial because it would provide valuable information as to why Mullumbimby’s sewers flooded so often.

‘This project isn’t about whether a vacuum system is better than a low-pressure system or not. It’s about measuring and monitoring sewer collection system performance or lack of it,’ Mr Dey said.

‘The low-pressure system has a pod in the backyard and so we will know how much sewage or stormwater is coming from each house. That data is fundamentally required.’

Produce the evidence

But Ms Warren disagreed.

‘Evidence of follow-up on illegal and faulty [stormwater] connections on private properties, which continue to be blamed for the inflow/infiltration, needs to be produced before expending any moneys on any trial,’ she said.

‘Council has already got the data on wet and dry weather inflows at each pump station to meet the aims of any trial so why have a trial?’ Ms Warren said.

‘If Council’s staff are still of the position that it is household connections that are responsible for the inflow/infiltration, pump station data can then determine which catchment areas of Mullumbimby they need to inspect to find these illegal and faulty connections.’