Thursday, May 03, 2007

Canberra Starts Potable Water Recycling

As of this week, all Canberrans are drinking some proportion of recycled water in their drinking-water supplies. I suppose this is a case of planned unplanned indirect potable recycling.

No advanced water treatment processes. No advanced risk management that we would normally associate with a planned indirect potable water recycling scheme. You be the judge of which approach carries the highest risks.

I’d be grateful for your thoughts.

Recycled sewage in our water already
By Cathy Alexander
Canberra Times
3 May 2007

Canberrans are already drinking recycled sewage.

Since Tuesday, Canberra's drinking water has been pumped from the Murrumbidgee River which contains treated waste water from towns upstream.

A heated debate has erupted in recent months over a proposal to put recycled sewage into Canberra's water supply via a massive new treatment plant. Critics have said there are serious health risks associated with drinking recycled sewage.

But the ACT Government has snuck under the radar, pumping the controversial product into Canberra's kitchens and bathrooms this week.

The Murrumbidgee has not been used for Canberra's drinking water since the 1960s, and it's being used now because of the drought and the shrinking dams. Up to 75 megalitres is being taken from the Murrumbidgee each day and added to the existing water supply.

Actew confirmed last night the Murrumbidgee did contain treated waste water from upstream towns, which would include sewage. An Actew spokeswoman assured the public the water met Australian drinking water standards, and had been fully tested for any health-related problems such as E. coli.

"We only extract if it meets the requirements," she said.

She also noted the waste water would have been heavily diluted by the time it reached Canberra.

Until Tuesday, Canberra's drinking water had been taken from pristine catchments only, and is not believed to have contained any waste water at all.

Canberra has not taken drinking water from the Murrumbidgee for 40 years. But with Canberra's water storages at their lowest level as the drought worsens, Actew decided to activate its Murrumbidgee pumps on Tuesday.

Chief Minister Jon Stanhope made the announcement in the Assembly yesterday. He warned of "grave circumstances" as Canberra's water supply dwindled, and lamented that forecasts of rain had not come true.

"Canberrans are today drinking water from the Murrumbidgee River ... that highlights the gravity of the situation," he said.

He also issued data showing that 2007 was on track to be the driest year on record for the ACT.

Meteorologists had predicted decent autumn rainfall for the ACT but the rain has not come.

Inflows into the ACT's water supply were just 11 per cent of the long-term average for the first four months of this year, Mr Stanhope said.

The long-term average for January to April is 43.5 gigalitres. This year, just 4.6 gigalitres has entered the system. Mr Stanhope said that was even worse than the horror year of 2006, Canberra's driest year on record so far. By this time last year, 6.5 gigalitres had flowed into the system. The total rainfall for last year was about 10 per cent of the long-term average.

"We hoped [2006] would never be replicated," Mr Stanhope said.

He said Canberra's dams were at 31 per cent capacity, their lowest ever level.

The Actew spokeswoman said up 75 megalitres a day could be pumped from the Murrumbidgee.

"It's the first time for the current Canberra community that we've done this," she said.

Actew prepared to pump water from the Murrumbidgee last week but the water level was so low, water could not be pumped out. Weekend rain lifted the river level enough to activate the pumps.

The Murrumbidgee water is being pumped by the Cotter pumping station to the Mt Stromlo water treatment plant, and then into Actew's supply system.

Actew is currently considering introducing Stage 4 water restrictions, which means no outdoor watering.


bernard said...

Thank you for your vey interested blog. I would like to set up a business in desalinisation in France. I would like to get some help about who is who in term of technology and actors in the market. Can you help me with this?

Stuart Khan said...

Bonjour Bernard,

I am aware of the really big water provision companies in France: Ondeo (Suez) and Veolia. However, I’m sure that there must be many smaller companies as well. My best advice would be to subscribe to a newsletter like Water Desalination Report, which will keep you informed.

I hope that is (at least some small) help to you!

Paul said...

governments will do and say anything to get people to drink recycled water. It's then a short stop to privatisation of the water companies with money flowing to plug up excessing spending on government depts and politicians' perks.

Stuart Khan said...

Here's an update from the Canberra Times today...

Claims of recycled water risk dismissed
By Cathy Alexander
Canberra Times
4 May 2007

The ACT's chief health officer has dismissed claims of a public health risk from water being added to the territory's supply from the Murrumbidgee River. Paul Dugdale said the water was "very safe to drink" after being treated at the Mt Stromlo water plant. Dr Dugdale said the river was being continuously tested and there were "people on standby to turn it off at any time" if there was a problem with water quality. He pointed to data from Actew which showed the level of E. coli (a critical indicator of water health) was about half the maximum allowed. Disease expert Professor Peter Collignon says he had serious reservations about drinking Canberra water now. This week Actew started pumping water from the Murrumbidgee for the first time in 40 years. The river contains some treated waste water from Cooma's 8000 residents.

Liberal water spokesman Richard Mulcahy said using the Murrumbidgee was an "unavoidable necessity", and that he believed there was no evidence of sustained organic contamination of the river. But Professor Collignon, an expert in infectious diseases and microbiology at the ANU's medical school, said there was a risk the water contained bugs which caused vomiting and diarrhoea. "It's taking up water that has got faecal contamination in it in some degree," he said. ''This is a fairly big step ... and it is a concern. "Was it necessary to do this? Are we taking this risk earlier than we need to?" He said he was worried the Murrumbidgee contained viruses, as well as the protozoans Cryptosporidium and Giardia, which could cause gut problems. But Actew said it took five days for water to flow from Cooma into the intake of Canberra's water system. The longer water rested, the more faecal bugs died off.

Actew data showed the level of soil in the water another critical indicator was well within limits. Waste water from Cooma made up about 1.5 per cent of the flow of the Murrumbidgee, according to Actew. Dr Dugdale said while Canberra's water system had not previously contained treated waste water from towns, it was important to note that the Googong Dam was not entirely pristine as it contained run-off from septic tanks from farms. He said Canberra had to take water from the Murrumbidgee River because dams were at 32 per cent capacity due to the drought. "We can't afford to let it all just flow past," he said. Water Minister Jon Stanhope said he was satisfied that the chief health officer had no health concerns about taking drinking water from the Murrumbidgee. He also said the ACT Government was in negotiations to buy water from dams upstream along the Murrumbidgee, if the dry conditions persisted.

W F Blog said...

Four years, Stuart - what changed?

Alexandra de Blas: So the message is that these pharmaceuticals are actually still active in the environment when they leave the treatment plant?

Stuart Khan: What we can say for sure is that they’re still present in the environment. As far as their activity goes, there are compounds that we know have effects on environmental organisms, and there are others that we suspect will have effects. The main one that a lot of research has been done on, is a particular drug called ethanol estradiol, which is the contraceptive pill, and the contraceptive pill is excreted in a significant amount unchanged, and so when that enters the sewerage treatment plant, it’s very difficult to break down that particular chemical, compared to natural oestrogens, to which bacteria are more used to degrading. And so we know that that particular compound has effects on fish at very, very low concentrations.

Alexandra de Blas: So were you able to measure this synthetic hormone in your study?

Stuart Khan: We did some studies where we measured this hormone, and we looked at how it’s affected in advance sewerage treatment processes, so nano-filtration, reverse osmosis, ozination of waste waters. The reverse osmosis pretty much was able to remove this compound completely from the water stream, the advanced oxidation processes, ozination, were more variable and depended very much on the applied dose of the chemicals and the retention time and the specific reaction conditions.

Alexandra de Blas: We’ve talked about the contraceptive pill, but what about anti-depressants. A lot of people are taking those these days.

Stuart Khan: Yes, anti-depressants are interesting, because the way many of them function is to control the neuro-transmitter seratonin, and seratonin is what gives us a sense of wellbeing or of happiness or depression. However, seratonin also controls a lot of other physiological pathways in different organisms that are totally unrelated to the way seratonin works in our bodies, and in our brains. And so we’re seeing all sorts of different things in snails and fish, and different gastropods, birth, spawning of eggs, and different development processes that are unexpected. The problem at the moment is that these compounds are not easily measured in water, and we haven’t been able to measure these compounds at the sort of significant concentrations that might be physiologically important.

Alexandra de Blas: What about antibiotics? Because humans and animals take an incredible amount of antibiotics.

Stuart Khan: Definitely we can see a correlation between concentrations of antibiotics in sewerage and the relative amounts of immune strains of bacteria to those particular antibiotics. Up until now, people have been concerned about the immune strains of antibiotics being developed in the human body, but there’s been very little previous study looking at the sewerage treatment plant, and that’s an environment where we know now that you do see large concentrations of antibiotic drugs, and of course you have large concentrations of bacteria. So the potential for antibiotic strains to form there is significant.

Alexandra de Blas: Knowing what we know about pharmaceutical drugs now, what work should happen?

Stuart Khan: The thing with pharmaceuticals, when we look at how much of these compounds are being used and excreted, we’re talking about pretty much the same mass per year of pharmaceutical drugs entering the environment, as we are pesticides, yet we have no regulations at all regarding what’s acceptable for different drugs. Much of the reason is because we haven’t well been able to establish what sort of concentrations are really significant for many of these drugs, so I think it’s time that we started to look at those issues, and we started to look at setting, or at least talking about, arguing about, what are acceptable limits that a sewerage treatment plant can emit, before they need to implement some further advanced treatment processes. And then we need to look at what’s acceptable in the environment, before we really need to start worrying about the concentrations of these compounds in a river, and start making sure that we either meet it at the source which of course is the preferable solution to stop these things going into the environment, or that we do something about cleaning up the situation that we have.

I imagine you are not condoning the use of the Murrumbidgee water - or is this another "It's done all over the world so let me do it my way" proposal.


Stuart Khan said...

Thanks W.F.,

Isn’t the internet a wonderful thing!

What has changed since 2003? Well, there has been a flurry of international research activity on most of the issues raised above and many millions of pounds, dollars, euros and yen invested. However, I think the advances in knowledge have been rather incremental, rather than there having been any major break-throughs. We certainly have a much improved understanding of how effective some advanced water treatment processes are for removing many of these chemicals. However, in terms of discharges from conventional sewage treatment plants, I think its fair to say that the issues remain much as they are described above.

None of what is described above is referring to (planned or unplanned) indirect potable reuse (IPR). It’s all referring to impacts on aquatic wildlife. Never in this discussion about IPR have I denied the impact of discharged chemicals on wildlife. For example see my earlier post on Environmental Estrogens. In fact, I have spent a considerable amount of time and effort during the last five or so years trying to raise awareness of such issues in Australia. If I could find some evidence that chemicals discharged from sewage treatment plants were having a detrimental effect on human health, this would strengthen my argument that we should be treating effluents to a higher quality before discharge to the environment. However, I have been unable to find any such reliable evidence that this is the case for tertiary treated effluent. I would be indebted to you if you could point me in the right direction.

I have been careful not to appear to either condone or condemn Canberra’s use of Murrumbidgee water. I think all IPR schemes (planned or unplanned) need to be rigorously assessed in order to make such judgements and I simply don’t have sufficient available information on this one. If you re-read the start of my post, you will be reminded that I merely encouraged people to judge for themselves whether they would consider the risks to be greater than or less than those for a planned IPR scheme. I think my general feeling for this is well implied by the context of the question. But even I have to accept that it really is done all around the world and that on the face of it, this appears to be a rather conservative example compared to systems such as the Mississippi River or the Thames Water Valley.

By the way, you accidentally included the wrong link for the source. I’m happy to provide the correct one.

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