Thursday, June 08, 2006

What’s so bad about “unplanned” recycling?

Water recycling proponents often like to remind the sceptics that all water is eventually recycled. What goes around, comes around. In many instances, the cycle from drinking-water to sewage and back again can be very short. Throughout the world, the vast majority of such situations tend to be classified as “unplanned” potable recycling. Strangely, there is an apparent perception that unplanned potable recycling is generally accepted to be “bad practice”.

I disagree on two grounds. First, I think it is naïve to assume that most such situations are truly “unplanned”, -I suspect “unacknowledged” might be a more accurate term. But more importantly, the suggestion that this is “bad practice” needs to be considered in respect of the alternative.

There is probably not a river in the world that is at least 100 km long and does not have an upstream wastewater discharge and a downstream potable extraction. That is simply the way we live and it is the only way most cities on the planet can survive.

If cities from Minneapolis to Memphis did not return at least some of the water they extract from the Mississippi, there certainly would not be sufficient water to sustain cities from Memphis to New Orleans.

Some important rivers in Europe can flow at around 70% treated effluent during dry weather periods (and, of course, less during wet weather). Examples include the Thames (London’s major water source) and the Spree (Berlin’s major source). If Spanish cities did not return effluent to rivers after use, most of southern Portugal would surely be uninhabitable.

Water belongs to all of us to share and it is our responsibility to keep the world’s rivers flowing as the principal means of distribution. Use it wisely and put what you don’t need back, I say. This is especially important for inland towns and cities.

Cities like Toowoomba and Goulburn have an incentive to grow and clearly water is a necessary factor for growth. “Planned” water recycling offers opportunities for these cities to supplement existing supplies. However, we must remember that all water used for “planned” water recycling is no longer available for “unplanned” water recycling. This is an important trade-off that we must keep a close eye on.

However, the situation is different for coastal cities. Those such as Sydney, Brisbane, Melbourne and Perth discharge most of their used water directly into the ocean, cancelling any opportunity for recycling. These are the cities which have an obligation to implement sustainable water recycling schemes to make sure that they squeeze every opportunity from every valuable drop.

Most major Australian cities are at the bottom of their water catchments, with few significant populations upstream. Thus, on world-standards we are extremely poor “unplanned” water recyclers. We waste our most valuable resource by using it just once and then dumping it straight into the ocean. Our major cities, therefore must instead become world-leaders of “planned” water recycling. This is the only way that we can hope to live in a vaguely water-sustainable way.

Water recycling promises significant benefits for Toowoomba and Goulburn, but is absolutely essential for Sydney, Brisbane, Perth and Melbourne.

Feel free to click ‘comments’ below and tell me I’m a goose.


Anonymous said...

You only have to look at recycled paper to see that quality gets lower evertime we recycle something.

You cant expect to keep recycling something and expect to have the same quality as the original version.

People who think we shoudl recycle our water need to wake up and have a good hard look at the real world!

Stuart Khan said...

Thanks for these comments 'Anonymous'. They are among the most interesting anti-water recycling comments that I have read.


Greg said...

Are you trying to tell us Stuart that there are no ill effects from unplanned potable re-cycling?

Stuart Khan said...

No. That would be too much of a generalisation to make. As I made very clear in my recent article in the Courier Mail “Drinking raw sewage is bad for you. It will make you sick and soon enough it will kill you”.

“Unplanned” potable recycling “schemes” vary considerably throughout the world. Those which do not rely on sufficient treatment (engineered or environmental) are a significant health hazard. Disease from sewage-contaminated water is amongst the biggest killers in some countries.

But I will say that a good unplanned potable reuse scheme (as you will predominantly find in the countries that I have included as examples) saves millions of lives. I’m sure that you can pull out a report of some ill-effect occurring at some time, some place. However, with proper water treatment and management, “unplanned” potable reuse is clearly not a major health risk. If it were, it is inconceivable that it could go unnoticed, affecting millions of people in highly developed countries.

iwtfjl said...

The comment above from anonymous cracks me up!

Greg said...

I found it interesting to find out that New Orleans does not utilise RO technology in it's water purification process! I also found it bewildering that they only test for Cryptosporidium once a month and with the amount of solid material that is extracted in the water purification process each year you would think that desal would be a much more viable, healthy and economical and environmemtally friendly option there. I certainly do not like the purification process they are using, could possibly cause widespread mental health problems! I may be wrong though!

Stuart Khan said...


Yes, RO is an extravagence that most cities in the world do not have the benefit of. Yet, (my point exactly is that) unplanned indirect water recycling works very well for them.

You are entitled to think that the water supply may "cause widespread mental health problems", but the fact is that there is absolutely no evidence of it.

Greg said...

The most effective means of providing water for SE Qld and solving Toowoombas dilemna would be by desal. Pump the desal water back into Wivenhoe, allow Toowoomba to draw on Wivenhoes water. Use the Brisbanes recycled effluent for industry and for agriculture coast to divide and allow Toowoombas recylced effluent to continue where it always has , down Gowrie Creek into the Ballone - Condamine river systems giving these rivers a cleaner constant flow of water! What the hell could be better then that?

Greg said...

Ohh and I fogot to mention, we would only need to use the desal water to wivenhoe in times of drought like now!

W.F. Blog said...

Hi Stuart,

In following a variety of your posts I think that you as, shall we say, as a vendor of RO water and the community as a purchaser of RO water are at odds. (and I am not trying to brand you negatively in that role.)

There is no real obligation on the community to prove that potable reuse is somehow unhealthy. As a customer they can simply say "No thank you" and move on to some other water supply.

You, as the vendor or maufacturer, have the obligation to prove to the satisfaction of the purchaser that your product is "safe".

The consumer has heard all kinds of reputable sources talk of "environmental oestrogens", "EDC's" etc etc in relation to STP outflows into the environment. These compounds are undisputably associated with adverse effect on humans.

You maintain there is an unprovable link between urban drinking water affected by IPR and the adverse health effects but the waters are muddied enough that the consumer would rather be cautious.

You need to solidly disprove the hypothesis "Drinking water sourced by DPR or IPR is unhealthy" because that is the cultural status quo.

Alternatively wait long enough for the consumer to slowly gain enough confidence to buy your product.

Stuart Khan said...

Hello WF Blog,

You would be mistaken to think that I am in any way a “vendor of RO water” (I am however, a member of the community). I don’t sell water treatment technology or water to anybody. I have no “product” for people to buy. Nor do I have a particular bias towards RO as a water treatment technology of choice.

However, I do admit a personal bias towards ‘sustainable water management’ in Australia. I do believe that this is an outcome worth spending effort on. One way of doing this may be to provide the community with information which may help to change widely-held assumptions, beliefs, myths and attitudes. I believe that the scientific community has an obligation to provide the wider community with supportable, accurate information, particularly in areas so crucial as public health and environmental protection.

You may be surprised to know that I am quite “neutral” on the question of potable water recycling for Toowoomba. The way I see it is that the proposed scheme is to cater for recent decades of population growth and to allow for further growth. Not having any personal financial interest in Toowoomba, I have no particular preference for increasing population growth there. If the city has reached its sustainable limit, so be it. I can’t see any good argument for expanded water capacity there being achieved by a scheme that is opposed by the community. It is a harsh reality that will be faced by more and more Australian towns and cities in coming decades.

Topics such as EDCs are of great interest to me and I aim to post some information here soon.


W.F. Blog said...

Stuart, you miss my point. I wasn't pointing the 'vested interest' missile at you but was rather using you as an example of proponents of recycling (as a sustainable water solution) and only in that context was I referring to you as 'vendor'.

The outstanding point is how do the vendors (not you as such) solidly disprove the hypothesis "Drinking water sourced by DPR or IPR is unhealthy"

Stuart Khan said...

Hello Greg (a few posts up now!),

I am sure that you are not alone in your preference for desalination over water recycling. There are many issues involved, but you may find the recent NSW Senate Inquiry into A Sustainable Water Supply for Sydney to be interesting reading. It provides a detailed discussion of many of these issues from a very current perspective. I acknowledge that some of the information in that report directly quotes myself (hence for me point to it to justify my own opinions would be somewhat circular). However, regardless of your point of view, factors such as energy consumption, carbon dioxide production and brine management would all need to be addressed.

Stuart Khan said...

Hello WF Blog,

Sorry…perhaps I am a bit too defensive! Your question is really a very good one and indeed a major challenge to science.

It is my opinion that there is plenty of current evidence available that drinking water that has (in part) been sourced from treated effluent can be (and is) done very safely.

However, to solidly disprove the hypothesis "Drinking water sourced by DPR or IPR is unhealthy" is extremely difficult and may be impossible. At the very least it would require detailed epidemiological studies with huge numbers of people. We would need to be able to statistically identify a one in a million additional cancer case (over a lifetime of ~70 years). Controlling a study of such large numbers of people over such a long period of time would be virtually impossible…we would need millions of people who never consume water sourced by DPR/IPR and a similar number who do. Then we would need to “control” each of these populations for other confounding environmental and lifestyle factors. Finally the word “unhealthy” leaves open a limitless number of potential effects that would have to be studied.

Such a massive study would be unlikely to be considered unless it could be justified on the grounds of serious scientific suspicion that such a relationship between (well treated) DPR/IPR and health exists. It is pretty difficult to find any evidence to justify that suspicion (taking into account my earlier comments regarding ill-effects to Greg, above).

Greg said...

I've been researching New Orleans given its position at the bottom of the Mississippi River water chain and the perceptions I have about water contaminents and there relationships to mental health and my concerns about the system they are using to treat there water.
First Finding: New Orleans Crime Rate

I,m not saying this is linked to there drinking water but it has prompted me to research the subject more thoroughly!

Stuart Khan said...


Sounds interesting. I will be interested in your findings.


mick said...

recycling should be done for industrial and agracultural purposes only and perhaps the brillaint idea of using the water gone down the drain during a shower too flush toilets! freeing up drinking water! also towns do extract treated water. But with one major difference which the water futres plan in toowoomba doesn't have. as creeks and rivers flow downstream the nasties in the treated effulent is absorbed buy grass and dirt on the banks etc furtilising the banks. this is how natures creeks and rivers clean themsleves and the oceans have this affect as well. this is one of my many concerns i have about toowoomba's water futures the water in dams is usally still and therfore cant furturlise anything thus staying in the water. RO technology can't get rid of every little small partical as some people lead every one too belive and will require alot of maintance too run. Do you trust the person maintaining it?? also where is in the world has a 25% mixture of effulent/drinkwater has been used? no body has yet too be able too answer me on that yet. sorry stuart if i sound abusive. I am a very open mined person and have done a lot of reasearch on this issue and am convinced we shouldn't be drinking recycled sewage at the proposed 25% for toowoomba

Anonymous said...

It is interesting to read comments on the possible environmental damage which could occur through the introduction of IPR water due to the increase in the use of plastic bottled water, and have opponents to IPR water suggest alternatives such as desalination and sourcing water from alternative supplies which are hugely energy intensive and would be far more environmentally damaging over time.

As for w.f. blog effectively requesting a 100% guarantee on the safety of DPR or IPR water by asking for a solid disproval that drinking water sourced by DPR or IPR is unhealthy shows a lack of understanding of the risks present in just about all the services and products the community accesses every day.

Are we able to ask the same question of our traditional sources for water? Can we solidly disprove that drinking water sourced from dams and bores is unhealthy?

All our sources of water will carry with it a risk. Due to the long period communities have been sourcing water from rives and bores, we simply accept the risks. Product water from an AWT plant carries with it much less risk to health through consumption then our current traditional sources.

Stuart Khan said...

Thanks Mick,

Your comments don’t “sound abusive” at all. I consider your concerns to be perfectly rational and I appreciate you expressing them here.

It is true that environmental residence in surface waters does provide an additional barrier for effective water cleaning. However, even this is not 100% perfect for the removal of all contaminants (and is, in fact, much less effective than the combination of RO and advanced oxidation as proposed for Toowoomba). Good evidence for this can be found in a published report titled “Pharmaceuticals, hormones, and other organic wastewater contaminants in US streams, 1999-2000: A national reconnaissance” (Kolpin et al, Environmental Science & Technology, Vol 36 (2002), Issue 6, Pages 1202-1211). Organic wastewater contaminants were identified in 80% of the 139 US streams sampled.

The important question is not whether the contaminants are 100% removed, but what are the public health (and environmental) implications of their presence at such low levels? This remains an open question, but it would be incorrect to state that public health implications have been identified in any way that can be currently scientifically justified. If this situation changes in the future, it will provide a strong basis for wider implementation of advanced treatment technology such as RO and advanced oxidation.

Your comment “Do you trust the person maintaining it??” is also very valid. This is (one of) the reasons that I have called for strong national and state guidelines to be finalised prior to full commissioning of proposed IPR schemes. If protocols to ensure worlds-best-practice risk management are not instituted at Toowoomba (or other Australian schemes), I would/will be as vocal as anyone else in calling for improvements. As a proponent of water recycling (where it can be shown to be the most sustainable option), protection of public health is absolutely crucial; –one public health “incident”, however minor, would be sufficient to set back opportunities for water recycling implementation by decades. The possibility of such an incident as a result of poor management practises is not a risk that Australians can afford to take.

Anonymous said...

Stuart: I appreciate your balanced approach to promoting water recycling. You have yet to convince me to support it (and probably never will!!) but at least you seem well informed and prepared to recognize the valid issues and your comments are more measured than what we have generally come to expect from other so-called "experts".

Anonymous said...

You are entitled to think that the water supply may "cause widespread mental health problems", but the fact is that there is absolutely no evidence of it.

So if there is no evidence it's safe or not, why do you push for it! What's your goal here.. Money?

Stuart Khan said...

G'day Jaun,

Unfortunately, money is one of the major impediments to water recycling in most places. It will always be cheaper to over-extract our natural resources than to apply advanced treatment needed for many forms of water recycling.

For this reason, I think it is very important for us to evaluate potential recycling applications in terms of a 'triple bottom line': environmental, social and economic.

Gerard said...

I found this really helpful, Anonymous' comment cracks me up :)) This is a really good article.. Just wondering if i cold use it for my research paper?

Stuart Khan said...

Thanks Gerard,

Of course! You are welcome to use any of the material from the blog for your research!


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