Delivering the Murray-Darling Basin Plan

Recycling wastewater currently discharged at sea can provide long term water security for The MDB. This would require construction of a pipeline from Sydney to the closest entry point to the Murray Darling System . probably near Bathurst NSW. I am sure that this is feasible after all CY O'Connor built the Goldfields pipeline over 560kms to Kalgoorlie in 1903. This would provide water to the Murray Darling system as long as Sydney produced wastewater . Additionally this would remove the partially treated sewage from the DOO and solve two environmental issues at the same time

“Nothing is off the table in the battle to deliver 450 gigalitres of environmental flows for the Murray-Darling” and it is in this spirit that I would like to suggest a potential long term solution that may be worth at least investigating for feasibility.
Every day 499 megalitres of semi- treated effluent is discharged from the Malabar sewage treatment plant into the ocean off Sydney (CSIRO,2019). There is significant potential for this resource to undergo tertiary treatment and be able to be diverted from the Deep Ocean Outfall (DOO) and into the Murray- Darling Basin.
Currently the DOO discharges onto the edge of the East Australia Current (EAC) and the partially treated sewage is allowed to drift southward eventually dissipating as the EAC breaks up in the Tasman Sea.
The DOO is not seen as a long term solution, as the Australian Water Association states “At least in the short-term, and from an environmental outcome perspective, the deep water outfalls are currently a viable option for the disposal of much of Sydney’s wastewater. However, Koop and Hutchings (1996) argue that from a water resource perspective, and because wastewater is a potential resource, disposal to oceans is probably not a sustainable option”. They assert that reuse and recycling of the wastewater must form part of any better use of the water resource, while conceding that community support, cost, environmental benefit, priorities, timeframes and different engineering options all need to be considered.
I acknowledge that there will be significant cost to upgrade current water treatment facilities and to pipe the treated water to a dispersal point in the river system. The CSIRO state that,” for a cost outlay of between A$7.3 billion and A$10 billion, sewage treatment upgrades can deliver between A$12 billion and A$28 billion in net benefits – that is, the financial benefits above and beyond what it cost to put new infrastructure in place” (2019). This does not include non-financial benefits such as improved marine water quality and improved flows in areas of the Darling which have not seen decent water flows in many years.
If this proposal were to be realised the input into the Murray –Darling Basin would be well in excess of 450 GL annually and likely to increase over time as Sydney continues to grow. It is important to note that this amount of water could be recovered from only one of many ocean outfalls in NSW.
This resource is currently providing little or no benefit to the citizens of Australia and yet it could be a valued resource and an environmental victory for both the marine life and the Murray - Darling River system.

Cost of construction and pumping stations to the nearest point to feed into the MD system likely near Bathurst NSW