31 October 2019
Improving environmental and public health outcomes from the Merimbula Sewage Treatment Plant (STP) were the focus of two Council resolutions at yesterday’s (30 October) meeting.
The first related to expanding the reuse of treated wastewater on the Pambula Merimbula Golf Club and elsewhere in the Shire.
Council resolved to allocate $65,000 to engage a consultant to undertake the irrigation capacity assessment, water balance and design of an effluent storage dam on the golf course, with a further $10,000 to be sought from the club for this work. An agreement will be negotiated with the club on funding any construction of a dam and Environment Protection Authority (EPA) compliance issues. Council also requested a full report with costings of all treated effluent re-use options across the Shire.
Council’s Director Assets and Operations, Anthony McMahon, said the golf club has been reusing treated wastewater from the Merimbula STP for decades, and this can be expanded by increasing storage capacity in partnership with the club.
“Where it makes sense from an environmental and economic perspective, we aim to reuse treated wastewater as much as we can. There are similar schemes at Bermagui, Tathra, Kalaru, Tura and Eden, as well as at Merimbula,” Mr McMahon said.
The second resolution involved the location and broad specifications of a proposed new ocean outfall diffuser to replace the existing beach-face outfall between Merimbula and Pambula.
This is part of a broader upgrade project to improve environmental outcomes, which also includes better treatment of effluent and improved wastewater quality.
Council resolved to construct the new outfall on a northern alignment 2.6 kilometres out to sea and 30 metres underwater, providing a sustainable disposal option to return treated wastewater back to the environment when it cannot be reused.
In addition, the decision was made to treat the water to a higher standard including an additional sand filtration step, further phosphorous removal and UV disinfection.
Mr McMahon said the new ocean outfall will deliver significant environmental, cultural and public health improvements over the existing beach outfall and exfiltration ponds.
“The existing exfiltration ponds in the sand dunes compromise ground water quality and cultural heritage values as there are sites of Aboriginal significance in the area,” Mr McMahon said.
“The new ocean outfall will take the treated discharge off the beach and away from the ponds, with better protection for the public and the health of our lakes.
“We recognise there may be an increased demand for reusing wastewater in the future and this plan allows us to respond to that while at the same time ensuring treated wastewater not able to be reused is disposed of in an environmentally responsible way.
“We’re looking at reuse and safe disposal in tandem, noting that there are no feasible options for 100% reuse in all weather conditions.
“The approved option for a north aligned 2.6 km pipe into the ocean is a cost-effective solution that will also meet ocean water quality objectives, safeguarding our environment, public health and aquatic industries into the future,” Mr McMahon said.
A decision on the location of the ocean outfall diffuser means the project team can move into the design and investigation phase and it’s expected that the Environmental Impact Statement (EIS) and concept design will be finalised in mid-2020. The EIS will further inform the final detailed design of the project.
The Merimbula Sewage Treatment Plant and Ocean Outfall Project is estimated to cost $35 million and is due for completion in late 2022.
A range of disposal and reuse options were considered by Council in earlier reports resulting in a decision to upgrade the STP and outfall in July 2013. The NSW EPA then amended Council's operating licence to include a requirement to construct an ocean outfall and upgrades to the STP.
More information about the project is available at www.begavalley.nsw.gov.au/MerimbulaSTPUpgrade
Reuse: Expanding the reuse of treated wastewater on the Pambula-Merimbula Golf Course and elsewhere in the Shire is to be thoroughly investigated.