Sunday, October 28, 2007

Drinking Recycled Stormwater

A few months back, there was some discussion on this blog regarding opportunities for the use of urban stormwater as a drinking water supply (see comments from Mark at the bottom of this post). An article from the Adelaide Advertiser this week, points to the likelihood of such a strategy being undertaken on a large scale in Australia sometime in the future.

The City of Salisbury in northern Adelaide is where most of the activity has been focused. A decade ago, the city began to investigate potential means of eliminating the flow of polluted stormwater into the environmentally sensitive Barker Inlet of Gulf St. Vincent. The Inlet is a significant fish nursery which supports the majority of South Australia’s fishing industry.

The key strategy adopted was the creation of wetlands for stormwater treatment. Some of this treated water is now reused for a variety of non-potable purposes in the region. The scheme has been very successful and there has been great interest in expanding it in order to be able to reclaim larger volumes of water.

Among the main challenges has been the need to overcome the seasonal variability between available water supply and demand. Naturally there is more stormwater available during the wetter months, but these wet months are when irrigation users (in particular) least require it.

To address this need for large-scale water storage, the CSIRO has spent more than a decade researching a process known as aquifer storage and recovery (ASR). This involves preparing the water to a suitable quality whereby it can be safely used to recharge a depleted aquifer and then recovered at a later time when required. The general concept is nicely summarised in the following figure from CSIRO Land & Water.

As the above figure indicates, ASR can be used for appropriately-treated reclaimed water from any source including stormwater and municipal sewage. Under suitable conditions, it can even have a significant benefit in terms of further improving the water quality during the process.

Given these benefits, it may be no surprise that the Government of South Australia and the National Water Commission appear to agree that there is great potential for Adelaide to use urban stormwater reclaimed by ASR as a future drinking-water supply.

The article from The Adelaide Advertiser appears below.

I’d be grateful for your thoughts or comments...

Stormwater for drinking
The Advertiser (Adelaide)
October 22, 2007
By Cara Jenkin

ADELAIDE residents will be drinking recycled stormwater as traditional water supplies continue to dwindle, says the National Water Commission.

South Australia's representative on the commission Dr John Radcliffe says treated stormwater will form part of SA Water's metropolitan supply in the future to ensure long-term water security in the city.

Dr Radcliffe said governments had traditionally treated stormwater as a "hazard" and as waste which could not be used.

He said stormwater should instead be seen as a resource.

"People naturally feel a little concerned about drinking water that doesn't fall off the hillsides, but some of these hillsides aren't that pristine," he said.

"All water is recycled water, that's the hydrological cycle."

Stormwater is already collected, stored and used for irrigation purposes in parks across Adelaide.

A world-first trial to treat stormwater naturally in underground aquifers to a standard suitable for human consumption is now under way at Parafield.

Dr Radcliffe said the trial was one reason why South Australia was more advanced in stormwater reuse than elsewhere in Australia. "One has to look at all water resources that are around and there is no perfect resource for a particular circumstance," he said.

"One of the benefits is that (treated stormwater) has a lot less salinity than is found in Adelaide tap water."

Treated stormwater will be added to the mains water pipes and dispersed among households.

The water will supplement existing sources but figures on what portion of existing supply could be supplemented are yet to be researched.

Draft guidelines on the use of recycled water for drinking have been developed by the National Water Commission.

They are expected to be endorsed by state water ministers, including SA Water Security minister Karlene Maywald, when they meet to discuss the guidelines early next year.

Wednesday, October 17, 2007

Election Promises

I happened to stumble upon two articles published in the Sydney Morning Herald on Saturday 7th January, 1995. They include lots of talk about phasing out Sydney’s ocean outfalls and recycling the water “for everything from industry to drinking”.

Oh…look out for that old line about water from the Rhine or Thames passing through eight sets of kidneys before it reaches the sea. Perhaps this was the original source in the Australian media?

The second article is particularly interesting. It features the then Labor opposition leader Bob Carr pontificating about ocean outfalls and arguing that Sydney's (coastal) sewage treatment plants must be upgraded to at least secondary treatment.

My back-of-an-envelope calculation tells me that roughly 2500 billion litres of primary treated effluent has been discharged from those outfalls since then.

The only thing different almost 13 years later is that nobody seems to care as much anymore.

A timely reminder about election promises...

Why Sydney May Soon Be Drinking Treated Sewage
Sydney Morning Herald
7 January 1995
By James Woodford, Environment Writer

Sydney's householders will be urged to reuse sewage effluent as drinking water under an ambitious new strategy to be launched next month by Sydney Water.

The plan is to persuade the public that the billions of litres of polluted water that pour into the oceans off the city need to be reused for everything from industry to drinking.

The release in the middle of next month of an issues paper - Choices Issues Paper No 1: Re-use - dealing with the reuse of effluent will be the most significant change in the way we get our water since the building of Warragamba Dam.

Community consultation, including the use of independent consultants, has played a crucial role in the development of the paper.

By July this year, Sydney Water's new legislation requires it to complete effluent reuse targets and in the long term contains an objective to phase out dry weather discharges from the deep ocean sewage outfalls.

The Environment Protection Authority (EPA) signalled this week that in the long term the $309 million outfalls will need to be phased out.

But according to Sydney Water, unless the public is able to change its attitudes about reusing effluent, it will be difficult to cut back on the use of the outfalls and delay the construction of new dams.

Some of the options for Sydney include:

* Sewer mining - tapping into the sewerage system to remove the effluent so it can be treated and used.

* Direct potable reuse - the establishment of a sewage-treatment system with possibly dozens of treatment plants, each serving several suburbs. The waste water from homes would be collected and highly treated and returned to the local water supply.

* Indirect potable reuse - the collection of vast quantities of highly treated effluent that would be pumped back into Warragamba Dam or Prospect Reservoir.

In all cases the water would be as clean, if not cleaner, than the present Sydney supply, says Sydney Water.

For the authority the prospect of water reuse opens up huge commercial possibilities and would ensure protection of the environment.

The treated effluent could be used for anything from industry, which would require less treatment, to domestic household use, including drinking.

The manager of demand management for Sydney Water, Mr George Bawtree, said: "Basically all of us here today are used to the option that there's fresh clean water out there for us to drink and that effluent is some other product.

"It (using effluent) requires a change in our perception of water. We will have to absolutely address this issue and it's absolutely critical that the community is part of this debate." Mr John Denlay, a researcher employed by the Sydney Water Project - an independent team of consultants set up by the then Water Board - prepared a study which analysed all of the reuse options available.

A shift to the use of "highly treated waste water" was the best way of drought-proofing Sydney, he said.

"Even during the drought we are still generating more than a billion litres of waste water a day that just pours out into the oceans." This water could be used providing the public was made comfortable with the idea that it was safe, he said.

In Europe and other parts of the world treated effluent had been commonly used for decades for drinking. "They say in the Rhine or the Thames that the water passes through eight sets of kidneys before it gets into the sea," Mr Denlay said.

"Reusing highly treated waste water for drinking purposes is well established overseas. For example, a plant in Namibia has been recycling up to 40 per cent of the water supply for the last 25 years.

"If the recycled water is only used for non-drinking purposes we will only be able to utilise 10 per cent of the waste water. To exploit the opportunities of reuse fully we also need to move to potable uses."

Carr Lashes 'hypocrisy' Over Outfalls
Sydney Morning Herald
7 January 1995
By Paola Totaro

The call by the Environment Protection Authority (EPA) to scrap ocean outfalls was hypocritical because it had consistently allowed the old Water Board to increase levels of toxic discharges into the sea, the Opposition Leader, Mr Carr, said yesterday.

A NSW Labor Government would immediately conduct a review of the operations of all sewage treatment plants to try to identify reuse options where possible and upgrade the plants to use the best technology for the least cost.

Mr Carr was responding to an EPA report which called for the phasing-out of the use of the $309 million sewage outfalls.

He said new outfalls were now planned at Coffs Harbour, Port Macquarie, Cronulla and Ballina, and Labor would place a moratorium on all such projects along the coastline.

"A moratorium is needed to force Government, the community and industry to seek environmentally responsible reuse alternatives to outfall disposal, including the use of new technology treatments," he said.

Mr Carr said that it was possible to stop short of upgrading to tertiary treatment levels while significantly upgrading the treatment already available.

"Tertiary treatment is a big step," he said. "We have to set that as a goal and move towards it. But before that, there is a lot you can do to upgrade (to) secondary treatment. That means reducing and setting targets to phase out toxic substances that are going into the ocean at the moment.

"No area in environmental science is developing faster than water treatment technology. We have an opportunity to use this cost-effective new technology that can significantly increase the treatment of water to tertiary standards." Mr Carr said the ALP would:

* Require the EPA to set targets for the phase-out of the dumping of toxic substances into the sewerage system, including mercury, cadmium and other bio-accumulating substances;

* Enshrine the $7 billion Clean Waterways program into special legislation to force Sydney Water to finance the upgrading of sewage treatment;

* Overhaul and tighten Sydney Water's pollution licences to require the progressive upgrading of ocean sewage treatment plants.

However, according to a spokesman for the Minister for Planning, Mr Webster, the new legislation which corporatised the Water Board provides a detailed framework to establish pollution targets.

You remember Sydney in 1995!

Friday, October 12, 2007

UV-Advanced Oxidation Seminar

In an earlier post, we took a look at the use of ultraviolet (UV) radiation for advanced oxidation treatment of organic chemicals in recycled water.

Most of that post was based on work undertaken at Duke University (USA) by Associate Professor Karl Linden and his research group.

Now we are very fortunate to have the opportunity to learn more about this important topic from Karl as he visits the University of New South Wales to give a seminar. This is a free public seminar and all interested persons are welcome to attend.

Ultraviolet light: Beyond water disinfection

Associate Professor Karl G. Linden
Duke University, NC, USA

DATE: Wednesday, October 24 2007
TIME: 12-1pm
VENUE: Room 701, Civil & Environmental Engineering (Building H20), University of New South Wales.


Although used in wastewater disinfection for years, ultraviolet light technology has only recently been seriously considered for drinking water treatment.

Because of its singularly high efficiency for inactivating protozoan pathogens, such as Cryptosporidium and Giardia, UV is now expected to be widely adopted for water treatment disinfection in the coming years.

But there is another side of UV not widely appreciated - that of contaminant remediation via photolysis and oxidation processes, specifically for water reuse.

UV mediated destruction of chemical contaminants is a very promising treatment process with interesting fundamental research opportunities and practical applications for indirect potable reuse.

This seminar will provide an overview of where UV technology for water treatment has been, and focus on the fundamentals of UV based remediation, drawing on our recent research findings for conventional and emerging environmental pollutants of concern in water including N-nitrosodimethylamine (NDMA), pharmaceuticals, and endocrine disrupters.

Some related recent Linden Group publications:

Chen, P.J., Kullman, S.W., Hinton, D., Linden, K.G. (2007) "Comparisons of Low- and Medium- Pressure UV lamps on the Removal of Bisphenol A Estrogenic Activity in Water following Direct Photolysis and UV/H2O2 Oxidation Processes" Chemosphere, Vo. 68, No. 6, 1041-1049.

Rosenfeldt, E.J., Linden, K.G., (2007) "Hydroxyl radical formation during the UV/H2O2 processes: The ROH/UV concept" Environmental Science and Technology. Vol. 41, No. 7, 2548-2553

Rosenfeldt, E.J., Chen, P.J., Kullman, S.W., Linden, K.G., (2007) "Destruction of estrogenic activity in water using UV advanced oxidation" Science of the Total Environment, Vol. 377, No. 1, 105-113.

Chen, P.J., Rosenfeldt, E.J., Kullman, S.W., Hinton, D., Linden, K.G. (2007) "Biological Assessments of a Mixture of Endocrine Disruptors at Environmentally Relevant Concentrations in Water following UV/H2O2 Oxidation" Science of the Total Environment, Vol. 376, No. 1-3, 18-26.

Shemer, H., Linden, K.G. (2007) "Aqueous photodegradation and toxicity of the polycyclic aromatic hydrocarbons fluorene, dibenzofuran and dibenzothiophene", Water Research, Vol. 41, No 4, 853-861.

Pereira, V.J., Weinberg, H.S., Linden, K.G., Singer, P.C. (2007) "UV degradation of pharmaceutical compounds in surface water via direct and indirect photolysis at 254 nm" Environmental Science and Technology Vol. 41, No 5, 1682-1688.

Wu, C., Shemer, H., Linden, K.G. (2007) "Photodegradation and Byproduct Formation of Metolachlor in Water via UV and UV/H2O2 Treatment" J. Agric. Food Chem. Vol. 55, No. 10, 4059-4065.

Shemer, H., Linden, K.G. (2006) "Photolysis, oxidation and subsequent toxicity of a mixture of polycyclic aromatic hydrocarbons in natural waters", Journal of Photochemistry and Photobiology A: Chemistry Vol. 187, No. 2-3, 186-195

Shemer, H., Sharpless, C.M., Elovitz, M.S., Linden, K.G. (2006) "Relative rate constants of contaminant candidate list pesticides with hydroxyl radicals" Environmental Science and Technology Vol. 40, 4460-4466

Chen, P.J., Linden, K.G., Hinton, D.E., Kashiwada, S., Rosenfeldt, E.J., Kullman, S.W. (2006) "Biological Assessments of Bisphenol A Degradation in Water following Direct Photolysis and UV Advanced Oxidation" Chemosphere Vol. 65, 1094-1102.

Shemer, H., Linden, K.G. (2006) "Degradation and byproduct formation of diazinon using UV and UV/H2O2 processes", Journal of Hazardous Materials Vol. 136, No. 3, 553-559

Shemer, H., Kunukcu, Y.K., Linden, K.G. (2006) "Degradation of the Pharmaceutical Metronidazole Via UV, Fenton and photo-Fenton Processes, Chemosphere Vol. 63, 269-276.

Rosenfeldt, E.J., Melcher, B., and Linden, K.G. (2005) "Treatment of Taste and Odor Causing Compounds in Water by UV and UV/H2O2 Processes", Journal of Water Supply: Research & Technology -AQUA Vol. 54, No. 7, 423-434.

Rosenfeldt, E.J. and Linden, K.G. (2004) "Degradation of endocrine disrupting chemicals bisphenol-A, ethinyl estradiol, and estradiol during UV photolysis and advanced oxidation processes" Environmental Science and Technology, Vol. 38 No. 20, 5476-5483

Sharpless, C.M. and Linden, K.G. (2003) "Experimental and Model Comparisons of Low- and Medium-Pressure Hg Lamps for the Direct and H2O2 Assisted UV Photodegradation of N-nitrosodimethylamine in Simulated Drinking Water", Environmental Science and Technology, Vol. 37 No. 9, pp. 1933-1940

Sunday, October 07, 2007

Wave Energy to Power Desalination?

Perth is the first Australian city to have its drinking water partly supplied by desalinated seawater. A 45 GL/year plant was constructed and began operation at Kwinana, 40 km south of the city in 2006. Since then, the West Australian Government has announced plans for a second plant to be sited 155 km south of Perth near Binningup and to produce another 45 GL/year desalinated water by 2011.

Among the major issues with seawater desalination is the necessary energy consumption and the associated greenhouse gas production and cost impacts. The Kwinana desalination plant is powered from the local power grid. While the grid is predominantly supplied by coal-fired power stations, the equivalent energy required for the plant has been formally off-set by the construction of a wind-farm about 260 km north at Cervantes.

After plans for the second (Binningup) seawater desalination plant were announced, a West Australian company began vigorously promoting a new energy-supply technology, which is currently under development. The company is Carnegie Corporation and the developing technology is named CETO, -possibly after the hideous sea monster from Greek mythology (or perhaps there is another explanation for the name!).

The CETO Technology is actually owned by the London-based Investment Company ‘Renewable Energy Holdings Plc’ (REH). However, CETO is an Australian designed and developed technology. Much of the development has been undertaken (and continues to be undertaken) by the Perth-based company ‘Seapower Pacific Pty Ltd’. REH collaborates with Carnegie Corporation on financing CETO development in the Southern Hemisphere.

CETO is designed to harness ocean wave energy by using it to pressurise seawater and transport it onshore. The energy from the pressurised seawater can then by utilised by pushing the water through a reverse osmosis membrane (to produce desalinated water) or recovered by using it to run a turbine (to produce electricity).

The technology behind CETO is relatively simple. A buoyant bladder is restrained just below the sea surface and moves in an elliptical path as a result of wave-action. The bladder is connected to a piston which moves inside a narrow pipe fixed to the sea floor. The movement of the bladder pulls the piston up and down, producing pumping forces. These pumping forces are then used to drive pressurised seawater to shore via a pipeline.

Proposed CETO Wave Farm (© SeaPower Pacific Pty Ltd)

Plans are currently underway for a pre-commercialisation pilot-scale trial of CETO at Fremantle (WA) during 2007-2008. Based on the success of this trial, it is hoped that the first full-scale implementation of the technology can be developed during 2009-2011. Carnegie Corporation expects that this timing is just right for CETO to be employed for Perth’s second desalination plant.

The possibility of using CETO to power the future desalination plant was recently discussed in a short article appearing in CSIRO’s Ecos Magazine. The article quoted Phillip Jennings, Professor of Energy Studies at Murdoch University pointing out that while the technology is exciting, it is currently experimental and untested on a large scale:

‘Currently, the government is looking for an assured water supply,’ says Professor Jennings. ‘If the new desalination plant is not reliably producing clean drinking water by the target date, there will be a shortfall in Perth’s water supply. ‘First, CETO would need to prove itself at a smaller scale for a use that is not as critical as Perth’s drinking water supply. The company needs to demonstrate that the technology would be cost-competitive at a larger scale with other energy sources, such as wind power.’

A recent independent technical appraisal of CETO was undertaken for Renewable Energy Holdings in the UK. It noted “…Even with this price advantage, the CETO device will require financial support either through capital grants at the front end or through ongoing support as is available through the Renewable Obligation arrangements in the UK.”

As a whole, Australian governments have generally been very poor at investing in renewable energy technologies (why would they when burning coal is so cheap?). In order for a technology like CETO to be fully developed and commercialised, it is likely that either some government incentive will be required, or that the Australian population simply demand (and be prepared to pay for) clean energy alternatives.

Of course, one government intervention that would drastically improve the competitiveness of renewable technologies overnight would be the implementation of a carbon tax. Even the indication that such a tax would be instituted some time in the future would stimulate research and development. But which Australian government would be so foolish as to implement something that would be so vigorously opposed by the lucrative fossil fuels sector?

An alternative strategy is to sit back and let innovative Australian technologies be commercialised by overseas companies and then Australia can contract those companies -at significant cost- when we finally decide that we need the solutions that they provide. This is the model followed for hollow-fibre microfiltration membranes currently being installed in advanced water treatment plants around the country.

The independent technical assessment of CETO identified the West Australian coast as “an ideal location for the [first full-scale implementation] due to the high and constant wave energy (waves over 2 m occur 90 % of the time) that occurs along the south west coast”. However, ultimately, the assessment authors concluded “that a good commercial project test site may be in Northern Ireland, where there is economic support available for renewable energy projects in terms of the NIROC, combined with a good wave energy resource”.


The above text may sound pessimistic about Australian inclinations to support the development of innovative energy sources. However, stock exchange investors have a solid reputation for their collective ability to predict future events and they appear to be optimistic.

The Binningup desalination plant was announced by the West Australian Premier on May 15 2007. From that date over the next four weeks, the Carnegie Corporation share price rose from around 3.5 cents to more than 20 cents. It has since corrected to around 13 cents, but it is still an impressive sudden rise.

The red line is the share price, the burgundy line is the 20-day moving average and the blue line is the Australian stock exchange index “S&P/ASX 200”.

I wonder whether similar impacts were observed for other West Australian energy sector companies...

[Please note that I am not in the business of giving investment advice and nothing on this blog should be mistaken for such!]