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Aug 20

But where does it come from?

Seem like a pretty trivial question, and I’d imagine most people would say anything along the lines of, “The tap”, “the lakes”, “the streams”, “the well” or even “the great land of Dasani”. And really, these are all essentially right. But that’s just the original source of the water, what about everything in between the source and the tap? (Bare in mind, I’m just going to touch on these topics, if you want to know more the internet is an amazing place).

Scrub Dub Dub. . .

No, the water doesn’t stop in a homophobic’s worst nightmare.

I should hope that the vast majority realize that the water they get from their taps isn’t “as is” out of the lake (I’ll mention now that I’m generalizing all this to water provided through some level of municipal infrastructure). Most water sources make their first stop in some form of water treatment facility. Many also stop briefly in a reservoir, but we’ll touch on that later.

Water treatment facilities are wonderful places that can do lots of things to the source water. Put bluntly, it cleans out all the harmful stuff that might be in there, as well as some of the stuff that makes it look poor or taste like it came from that over populated tub.

In no specific order, and in no great detail (because I’m not keen on reproducing all my notes from Water and Wastewater Design), and likely missing some other steps, the things we can do to water in a treatment facility include:

  • Screening: Removing big things, like stick, garbage or goats. . .
  • Filtration: Removing small things. . . like silt, sands and even bacteria
  • Coagulate and Flocculate: Making REALLY tiny things bigger, so they can be removed with Filtration or settling
  • Settling: Letting stuff sink out of the water
  • Aeration: Makes stuff float to the top of the water so we can scoop it out. . . like the flocs we made in flocculation. It also helps remove minerals that can make the water look or taste bad.
  • UV Treatment: Kills/deactivate microorganisms that can harm us. It doesn’t remove the subject contents, but rather renders them unable to make us ill.
  • Chlorination: Kills/deactivate microorganisms. Unlike UV though, we can put a residual amount of Cl in so that is can continue to disinfect the water as it travel between the treatment facility and your tap.

What happens to the water in a treatment facility is completely dependent on what’s in the water to begin with. If the water came straight from Dasani-land we may not do very much to it (possibly a little chlorination for the road, but that’s a different story).

Time for a Rest

What do most people do once they’ve gone to the spa? Take a nice long rest of course!

Okay, maybe they go do other things, and maybe a spa is a really bad metaphor for a water treatment plant, but regardless, most water will make its way to some place for a rest after being treated. This is water we call a reservoir.

There are lots of kinds of reservoirs out there: concrete boxes, steel tanks, water towers, or even open air ponds. Now-a-days most reservoirs are sealed and monitored structures where the water is protected from exposure to the elements, and more importantly, anything that could dirty or infect it! It makes sense since we just put all the effort of making it all clean and tasty!

But why do we keep it in storage? Why not just pump it right out into our taps?

What a great question! And there really isn’t any one reason, so I’ll list some:

Fire flows: When fires occur, those shiny red trucks pull A LOT of water through the distribution system. Put simply, if we didn’t have big boxes of water sitting around the area those trucks would suck the pipes dry. . . and then we’d have even more problems in addition to Billy Bob’s shack burning down.

Energy Saving: Water unfortunately doesn’t flow uphill. So we pump it instead. If we had to equip our systems to pump water from the source to all the taps during peak hours we’d have to have a lot of massive pumps. And then during the day when less water is used, most of those pumps are just sitting around. So instead, we use fewer smaller pumps over longer period time to fill these boxes when there isn’t a lot of demand. Then, once there is a lot of need for water, rather than pumping it all from the source, we can let it fall out of our tanks (did I mention reservoirs are usually kept in higher locations, like on hills above town? Or where there aren’t hills, in tall water tanks? There, now I have and now you know).

Redundancy: Is really a wonderful thing when you’re dealing with unstable systems. What’s an unstable system? It’s one that’s not stable. Still lost? It’s a system that doesn’t remain in a constant state. Why is water distribution unstable? Because we all open taps, close taps, flush toilets, have showers, wash dishes, water the lawn etc etc. So water is constantly moving and stopping and going different places. If we tried to just pumps this from our source, the pumps would be on and off all day, which would easily wear them out. And I won’t even get into water hammers. . . short story: they break everything! having reservoirs in the system helps to relieve these issues by providing various sources where water can be drawn from, meaning that any one source or pump has to work excessively hard whenever you feel the need to wash your abundant head of crazy curls.

Okay, I’m really dropping the ball on reservoirs, so I’m going to move on and come back to this another day.

The Long Lonely Road

So, we find water somewhere, we make it pretty and tasty, we store it in a box, but how did we get it from A to B to C to tap?

Pumps and pipes do all the work! I’m going to leave out valves and monitoring and control systems, but they’re there too. Oh, and the many operators that keep everything in order (most of the time).

I don’t think I really need explain these two things too much. Pumps pump. They also provide pressure to the system so that you can wash your car. And pipes are pipes. . . They can be a variety of sizes, from 3/4″ (which believe it or not, is the size of pipe all the water for your house likely comes from) to massive 120″ or bigger.

End of the Line

Now, I’ve really over simplified this, and probably missed some points, but I hope it added even a small amount of insight into the water you use everyday. Where this whole post spawned from was a discussion as to why we have to pay for water. “Water is free, but clean water delivered to your tap costs money”. Anyone can walk to the nearest stream with a bucket and fill it up, but to have that water cleaned, disinfected, stored and distributed costs big money. But, these systems are out of sight which takes them out of mind, so it can feel like your money hasn’t really gone anywhere. Hopefully, you’ll now think a little more about your water today.