Monday 30 April 2007

Water Recycling

There's something I have yet to understand about the water recycling debate, something which highlights in a way that more mundane matters can't the absurd lengths to which the human mind is capable of going in selective perception and self-deception.

The "ew, gross!" factor.

Drinking recycled sewerage? Ew, gross!

Let's think about this for a minute: Where does your tap water come from? From a dam. With a thriving ecosystem in it, consisting of plants, microorganisms flaural, faunal, bacterial and viral, and fish and smaller animals which eat, defecate and breed well enough to keep fishermen happy. That water then flows, sometimes directly and sometimes via a river, into the mouth of a pumping station which carries it off to a treatment plant which, when it's done with the water, pumps it off towards your home.

Now let's consider where sewerage goes. From your house it gets pumped (or flows, or oozes) to the sewerage treatment plant which, after doing somewhere between the bare minimum of filtration and drinking-quality treatment, pumps it by a more or less roundabout route into the sea. Where it mixes with the water that's already there. Then evaporates, into clouds. Then falls as rain, onto land, where it flows into the dams that release their water into the treatment plant which sends it to your kitchen tap.

There is, short of a large-scale application of simple physical chemistry, no such thing as water that hasn't been recycled. It just takes longer if you don't think about it too much and let nature do most of the treatment for you.

Or, in the case of large parts of Australia at the moment, it doesn't happen at all. Which is why we are attempting to short-cut the whole sewerage-sea-evaporation-clouds-rain cycle by desalinating seawater and purifying waste water. Which will, in either case, get pumped into the dam where it gets to sit, being part of a thriving ecosystem, until it gets pumped into the treatment plant...

You're drinking recycled sewerage already. Deal with it. All that a waste-water treatment plant is doing is testing the rainfall before it goes into the dam.

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