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Comment by kbutler | Hacker News Reader

The problem isn't just contagion theory: it's percentages.

We know that the treatment process doesn't remove everything (witness the taste of tap water in various cities).

Purification rates are generally stated as percentages, suggesting that the dirtier the input, the dirtier the output (GIGO)

Searching for "waste water treatment effectiveness" yields interesting articles about failures - for instance: http://www.cabq.gov/progress/public-infrastructure/dcc-18/in... which indicates that upstream failures treating the waste water increase health risks and treatment costs of water users downstream - why should it matter without the GIGO principle above?

How sure are you that the treatment systems remove 100% of the micro-organisms? 100% of the chemical hazards? All the time?

There's definitely room for concern, even on the purely scientific/engineering side, though advocates say that the treated waste water is the cleaner water source.

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"How sure are you that the treatment systems remove 100% of the micro-organisms? 100% of the chemical hazards? All the time?"

I am 100% sure that they do not. It's impossible. No water in nature is that clean, either, by any standard.

But also, you are not a wilting flower that can only survive on the purest triple-distilled angel tears. There absolutely is a such thing as "good enough" and any water that meets existing US standards is well in excess of "good enough". It is certainly far, far, far cleaner than anything your ancestors ever had to drink!

This isn't about safety. All "room for concern" has been abundantly addressed; US water standards are incredibly strict both in theory and in practice. It is entirely about psychology.

The article, and all of the responses I've seen so far, all ignore the problem that sewer water is overflowing with the prescription drugs that people have consumed. Municipal water AND many bottled water suppliers don't even bother testing for drug contamination.

http://thelede.blogs.nytimes.com/2008/03/10/there-are-drugs-...

Broadly speaking, I would consider the burden of proof to be on those who say that things in concentrations measured in small numbers of parts per billion are really bad and worth panicking over. It may be, it can not be ruled out, but the list of things that you routinely consume, that you can't help but consume, at similar concentrations would blow your mind.

Heck, a complete rundown of every microorganism you just ingested the last time you took a breath would blow your mind. (Mine too. I'd love to see it.)

The world is a dirty, dirty place, and always has been. You aren't a wilting flower, you are the product of billions of generations of organisms that survived, all of which except maybe the last three generations lived in a radically dirtier world than you do. I'm really not that worried about ppb pharmaceuticals in my water; if I'm going to go that route I'm going to finger my food for things like hormones and antibiotics long before my water.

http://www.usatoday.com/news/nation/2008-03-10-drugs-tap-wat...

""" Troubled by drugs discovered in European waters, poisons expert and biologist Francesco Pomati set up an experiment: He exposed developing human kidney cells to a mixture of 13 drugs at levels mimicking those found in Italian rivers.

There were drugs to fight high cholesterol and blood pressure, seizures and depression, pain and infection, and cancer, all in tiny amounts.

The result: The pharmaceutical blend slowed cell growth by up to a third suggesting that scant amounts may exert powerful effects, said Pomati, who works at the University of New South Wales in Sydney, Australia. """

Unfortunately (and I mean that, I wish this style worked better than it does because it is so easy compared to real experiments), that style of experiment is well known for producing useless results.

Think about it; if the water was that poisonous, such that 1/3 of our celluar growth was being eliminated, we wouldn't be speculating about whether our water was killing us, we'd know and long since have taken some sort of action. The strength of the real signal is bounded by the fact that we have millions upon millions upon millions of real people consuming these things every day. Reality always trumps both theory and experiment, and don't ever listen to anybody who forgets that. An experiment that shows an enormous signal, which we can observe in the real world can not possibly be occurring, is far more likely to be a flawed-beyond-usefulness experiment than a real reason for concern.

It is, however, a great way to get in the news.

You get the same problem when some people discover that X causes cancer, except that if you take their results seriously you end up with (metaphorically) 245% of the population dying of cancer X by the time they are 30. Except we don't. Hidden dangers can only be so dangerous.

Orange County in SoCal has been doing this for a few years. They start with the type of treated sewage you mention above; then they microfilter it; then they do reverse osmosis; then they treat it with UV and H2O2; then they use it to recharge the aquifer (where it takes some time to trickle through before they pump it back out of the wells).

http://www.gwrsystem.com/the-process.html

People believe in homeopathy! so even if there is 1 billionth of the original dirtiness left, they think that could effect them.

Wouldn't that get counteracted by the one-trillioneth antibiotic element?

You can never be 100% sure because science has no way to count to that level of accuracy. But you can take samples to validate that a scientifically proven process is working correctly. The ability of chlorine to purify water is quite well understood.

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