"Reuse or wetlands, they're just add-ons, but in terms of what we do when it rains for six months there are only three options," BVSC water and sewer engineer Chris Best said.
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"Reuse and the outfall are two different matters which have to be looked at separately."
He is referring to the proposed Merimbula ocean outfall project which will deal with treated effluent from the Merimbula sewage treatment plant. This is the treatment plant for sewage from Merimbula and Pambula. Around the shire are nine other treatment centres.
The Environmental Protection Agency (EPA) has mandated council must find a way to deal with effluent it can't contain or can't reuse because those organisations taking the water do not want it due to wet weather.
It's basically about dealing with the overflow or extra treated effluent that is not required elsewhere.
"There are three options, an outfall for treated effluent, dunal ex-filtration or reuse as drinking water," Mr Best said.
"We asked the community working group about drinking purified and recycled water and they said 'no'," Mr Best said.
With no appetite for recycling as drinking water, the committee considered dunal ex-filtration which was thought to be an option before the focus group was formed in 2012 and was a staff option.
Two major issues with dunal ex-filtration
However that was before the full impact of what was currently taking place was brought home by the EPA representatives on the focus group.
"The EPA realised the impact on the Aboriginal community; the whole strip has artefacts," he said.
In fact there are nine Aboriginal graves in the area.
"How can you condone pouring treated effluent on graves," Mr Best said.
And there is also another issue, an endangered ecological community, the Bangalay Sand Forest.
The Threatened Species Conservation Act lists Bangalay Sand Forest as endangered. Bangalay Sand Forest is a community of over 50 endemic species including Eucalypt, Banksia, Dianella and Dichondra, among others.
South of Bermagui less than 40 per cent of the estimated pre-1750 distribution was still around in 1999.
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Degradation occurs where Bangalay Sand Forest is exposed to disturbance and pressures associated with increasing human populations, especially where stands of the forest occur in the vicinity of coastal villages and urban centres.
The NSW Scientific Committee is of the opinion that Bangalay Sand Forest is likely to become extinct in nature in NSW unless the circumstances and factors threatening its survival cease to operate.
"We knew then the only overflow option was an outfall," Mr Best said.
Pressure put on council to meet standards
Council's licence with the EPA, which allows the continuation of the existing beach face outfall until an alternative is built, states that an ocean outfall will be built. It is written into the licence that allows council to continue to operate the current Merimbula treatment plant.
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Mr Best admits that council has been under pressure from the EPA and in 2009 the licence stated that council would be taking further measures. Council expanded the reuse of treated effluent into Oaklands. Currently between 15 and 30 per cent of treated effluent is reused from the Merimbula plant.
Non-compliance of the EPA terms could mean hefty fines for council.
Taking a dump has new meaning for farmers
There is some good news; 90 per cent of biosolids are reused.
"Before 2019 all the annual generation of 6000 tonnes per year of biosolids went to landfill. We now target 90 per cent of that to be diverted to our contractor Arkwood to use on local farms.
"With the remaining 10 per cent we are working to use that on site at our sewage treatment plants. Almost all of our biosolids will now avoid landfill, and most will benefit our farmers," Mr Best said.
At the Merimbula sewage treatment plant in the areas that contain the drying biosolids, tomatoes are rampant. The nitrogen-loving plants whose seeds pass through our systems thrive in the conditions.
READ ALSO: Where our recycled water goes (2017 story)
Council is currently investigating the costs associated with irrigation to the Pambula Sporting Complex and while Mr Best admits there are issues associated with irrigation he believes they are solvable.
One such issue is using treated effluent on a playing surface where people may cut or graze themselves, for example a football field.
Placing the irrigation underground or using a treatment barrier may mitigate those issues, however it is not expected to increase reuse by more than a few per cent.
"There are around 7ha of sports fields at the Pambula Sporting Complex which could benefit from reuse. We are working on a cost estimate and reuse volume. There is a lot to think about when planning a new reuse scheme and council is committed to looking for potential reuse projects for the whole shire," Mr Best said.
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He said that potential reuse from the Merimbula treatment plant was "really limited" because of the terrain, cost to run a pipeline out to somewhere that might only take a small quantity of treated effluent, and the restrictions on where it can be used.
For example it cannot be used in national parks or where it may run off into our lakes because of the oyster industry.
So what about Byron Bay and Shoalhaven schemes?
People have referred to the Byron Bay scheme which uses treated effluent on man-made wetlands but Byron Bay doesn't have an oyster industry to protect around the ocean mouth of the creek that the wetland discharges treated effluent into Mr Best explained. There are some leases in Byron Bay but not near the sewage treatment plant.
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"Byron only reuse 40 per cent of their treated wastewater in reuse schemes. The rest falls through the wetland and into groundwater or the creek which goes to the ocean," Mr Best said.
They have already spent over $100m for a sewage treatment plant upgrade but they still have to keep their outfall.
- Water and sewer engineer BVSC, Chris Best
Several people have also referred to the Shoalhaven REM scheme.
"They are getting 30 per cent reuse and have a lot of farms on flat land within easy reach but they are spending another $30m and hoping to reach 80 per cent reuse. They have already spent over $100m for a sewage treatment plant upgrade but they still have to keep their outfall," Mr Best said.
"It looks like we will manage 20-30 per cent reuse in this (the Merimbula) scheme and more in other parts of the shire. But we still need something right now to fix the beach face outfall and dunal ex-filtration."
