Tuesday, July 18, 2006

Liverpool to Ashfield Pipeline

Sydney Water and the NSW Government have clearly been working hard to identify new opportunities for water recycling. The 2006 Metropolitan Water Plan describes some major schemes currently under development. These include supplementation of environmental flow in the Nepean River (Western Sydney Recycled Water Initiative); significant expansion of dual-reticulation schemes in north west and south west growth centres; and a major industrial reuse scheme (Bluescope Steel, Wollongong).

However, there is one opportunity which, although it is right under our noses, seems to be eluding all attention. So let me tell you about the Liverpool-to-Ashfield pipeline.

Sydney Water workers recently began boring a 20-metre hole into a reserve at Park Road, Ashfield. This is part of a$110-million project to build a 24 kilometre pipeline from Liverpool, a major component of the South Western Sydney Sewerage Scheme.

Two of Western Sydney’s largest inland sewage treatment plants are at Glenfield and Liverpool. Together these produce more than 50 megalitres of tertiary treated effluent per day. Historically, effluent from this area was discharged into the Georges River. However, to improve the water quality in the river, this practice has been largely discontinued. Instead, the treated effluent is dropped straight back into the sewer, where it is mixed with raw sewage and flows all the way to Malabar. At Malabar, the mixture then undergoes primary treatment before being discharged via the deepwater ocean-outfall.

Click on the map for a larger image

South West Sydney is a major growth area and increased capacity is required in the north Georges River sewerage sub-main to allow for development. The aim of the Liverpool-to-Ashfield pipeline is to free up capacity in this sub-main by diverting flows from the Glenfield and Liverpool sewage treatment plants.

The pipeline would carry tertiary-treated effluent 24 kilometres through some of Sydney’s most densely populated suburbs and industrial areas. However, when the water reaches Ashfield, it will again be dropped back into the old sewer, where it will again be mixed with raw sewage and transported to Malabar for discharge.

The pipeline is due for completion in 2008 but future options for reusing the treated effluent are not intended to be considered until 2010. This is a short sighted decision that should be revisited as a matter of urgency.

The Liverpool-to-Ashfield pipeline is new infrastructure and as such, provides a unique opportunity for planning for access to the recycled water. Expressions of interest should be sought immediately from local government and industrial water users to make use of this water as a replacement for current potable-water use. Obvious examples include irrigation of public parks and playing fields. There is also considerable heavy industry in the areas around Liverpool, Bankstown and Strathfield. If such interest is sought, this would allow Sydney Water to optimally plan the pipeline before it is completed and rendered inaccessible or unsuitable for access. Planning should include identification of the optimum precise path for the pipeline, any additional branches that may facilitate access, and the implementation of usable access junctions. The diameter of the pipeline should also be carefully considered to provide for optimum flow regimes facilitating access.

Under normal circumstances, ideas for sewer mining are commendable. However, in this case, we are dealing with water that has already had considerable energy-investment in bringing it up to a tertiary-treated quality. It seems sheer madness to throw that away by then mixing it with raw sewage. Our aim should be for nothing more than a trickle of water to actually reach the sewer junction at Ashfield. Come on NSW, let’s do something novel and plan before we build!

7 comments:

Anonymous said...

if the sewerage water is so good, why dont you just put is straight back into the dams like you want to do for Toowoomba? Or does the fact that you actually live in Sydney have something to do with it?

Stuart Khan said...

At the risk of sounding like a broken record… I have never tried to tell Toowoomba how it should manage its water, -a review of previous posts and comments will confirm that. I have also acknowledged (actually, ‘promoted the fact’ would be a more accurate term) that there are lots of good ways to recycle water. Potable reuse can be a safe, viable option and may be the preferred option when specific circumstances prevail.

In this particular case, there is a very simple, very cheap option for non-potable water reuse. If planned and managed well, it has the potential to directly replace what would otherwise be potable water use. The alternative option of treating this water to a potable standard and pumping it back up into the reservoirs would not be justified since it would be considerably more expensive, more energy-intensive, and provide little additional benefit.

Jaun said...

Recycled Water water should only be used for NON-DOMESTIC use, it is not needed as drinking water. Cities can save just as much water by using it in areas where high volumes of drinking water is used.

This is the simple fact, and it's just that council's and governments are just too f...... lazy to implement the technology in the correct manner.

Anonymous said...

I agree - your proposal for the new pipeline is a great idea!

Stuart Khan said...

A quick update to this story… the following article was recently published in the Inner West Courier. Its good to see that Sydney Water is “open to suggestions”, but there is little point waiting for councils and businesses to propose uses for recycled water. The missing steps are to raise awareness regarding the possibilities and to call for expressions of interest. Obviously the possibilities are significantly more restricted once the pipeline is actually constructed.

Boost to main

13Sep06

STRATHFIELD residents could have recycled water piped into their homes by 2012.

Construction is due to start on the Liverpool to Ashfield pipeline within the next few months, potentially providing treated waste water to homes along the route.

The 24km pipe will boost sewer main capacity during the refurbishment of the St George trunk main but could be used for recycled water once that project is done.

A Sydney Water spokesman said the sewer was being built to cope with population growth in South West Sydney but could be used for recycled water if councils and businesses proposed it.

``We will liaise with councils or businesses that are interested in receiving treated water from the pipeline,'' the spokesman said.

``We're open to suggestions.''

The water could be used for parks, gardens and sports fields and achieving drinking water quality was ``technologically possible''.

The spokesman said road closures and some disruption was ``unavoidable'' but boring tunnels under major roads should avoid extensive roadworks. Residents will be notified in advance of work nearby and there will be tight time restrictions on when it could be carried out.

The pipe will run through Strathfield via the Hume Highway to Hedges Ave, through land between Cave Rd and the highway, diagonally across Fitzgerald Crescent to Verona St, along Verona St, through Humphries Reserve and up Long and Plymouth streets into Burwood.

Leighton Contractors have won the tender to build the $131 million pipeline, which is expected to be finished by mid 2008.

Anonymous said...

Did you see Morris Iemma's election campaign speach today? Looks like you got your pipeline!

Stuart Khan said...

A later post provides a more recent update on the Liverpool-to-Ashfield Pipeline.

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