WEBVTT - Well Well Well 0:00:04.400 --> 0:00:12.640 Welcome to text, a production from I Heart Radio. Hey there, 0:00:12.640 --> 0:00:15.920 and welcome to tech Stuff. I'm your host, Jonathan Strickland. 0:00:15.920 --> 0:00:18.079 I'm an executive producer with I Heart Radio, and I 0:00:18.120 --> 0:00:23.319 love all things tech, and I don't think there is 0:00:23.560 --> 0:00:27.240 a more trite or obvious way to start an episode 0:00:27.480 --> 0:00:31.160 this year than by saying, twenty has been a tough year. 0:00:31.600 --> 0:00:33.760 And I'm not going to go through the list of 0:00:33.800 --> 0:00:36.519 all the things that have been tough, because all of 0:00:36.520 --> 0:00:40.360 you listening are aware of most, if not all, of 0:00:40.400 --> 0:00:44.400 those reasons. However, one of the things, a very localized 0:00:44.440 --> 0:00:49.199 thing that hit my neighborhood in Atlanta was a massive 0:00:49.320 --> 0:00:52.519 water main break. It actually happened along the border of 0:00:52.560 --> 0:00:55.360 the Georgia Tech Campus, which is, by the way, not 0:00:55.480 --> 0:00:58.360 close to where I live, but it is in the city. 0:00:58.560 --> 0:01:02.120 And that break meant that thousands of homes, including mine, 0:01:02.680 --> 0:01:06.520 lost water pressure, and it took quite a while before 0:01:06.560 --> 0:01:09.600 water pressure was restored, and even then we were all 0:01:09.640 --> 0:01:13.039 on a boil water advisory for several days. So in 0:01:13.080 --> 0:01:15.480 this episode, I thought maybe we could talk about the 0:01:15.520 --> 0:01:19.200 different technologies we use to supply homes with water, from 0:01:19.400 --> 0:01:23.479 personal or community wells to large municipal systems and why 0:01:23.520 --> 0:01:26.600 that boil water advisory was necessary in the first place, 0:01:26.640 --> 0:01:29.000 and we'll get to all of that. It's a lot 0:01:29.040 --> 0:01:32.680 of interesting tech and and ways that we have come 0:01:32.800 --> 0:01:36.320 up with clever solutions to the issue of getting water 0:01:36.560 --> 0:01:41.440 to people. Let's begin with just some basic facts about water. 0:01:41.840 --> 0:01:46.040 This is like elementary school level stuff. So on our planet, 0:01:46.480 --> 0:01:49.720 it's the only stuff you can find occurring naturally in 0:01:50.120 --> 0:01:53.360 three of the four states of matter that would be 0:01:53.520 --> 0:01:58.560 solid or ice, liquid you know, water and gas or 0:01:58.600 --> 0:02:02.400 water vapor. You don't tend to find it occurring as plasma, 0:02:02.680 --> 0:02:07.720 the fourth form. It's more dense as a liquid than 0:02:07.800 --> 0:02:10.240 it is when it is a solid, which is why 0:02:10.320 --> 0:02:13.600 ice will float in a glass of water. The Earth 0:02:13.639 --> 0:02:16.960 has a water cycle that is pretty much self contained. 0:02:17.000 --> 0:02:19.960 You know, we aren't really losing water out to space 0:02:20.720 --> 0:02:24.000 beyond some relatively tiny amounts here and there in some 0:02:24.200 --> 0:02:27.720 very specific circumstances, like if we send water up with 0:02:27.800 --> 0:02:31.280 astronauts and some of that water gets vented out into space, yeah, 0:02:31.440 --> 0:02:35.080 that's gone. But the stuff that is here is staying here. 0:02:35.320 --> 0:02:37.400 The water cycle is one that I'm sure you're all 0:02:37.440 --> 0:02:41.720 familiar with. Liquid water evaporates into water, vapor, which goes 0:02:41.760 --> 0:02:45.640 into the atmosphere where it will eventually condense and form 0:02:45.680 --> 0:02:50.760 into clouds, and at high enough concentrations with seed particles 0:02:50.919 --> 0:02:54.880 in those clouds, droplets will form until they're big and 0:02:54.960 --> 0:02:57.960 heavy enough to fall back to Earth as rain or snow. 0:02:58.320 --> 0:03:01.360 In addition liquid water, it can run across the land. 0:03:01.639 --> 0:03:04.560 This is called runoff and into the ground. This is 0:03:04.560 --> 0:03:09.520 called percolation and infiltration, and then eventually through the ground, 0:03:09.680 --> 0:03:14.359 seeping down through the ground and becoming groundwater. Plants absorb 0:03:14.440 --> 0:03:17.120 water in the ground through their roots, and then water 0:03:17.240 --> 0:03:20.320 evaporates from the leaves of plants into the atmosphere, and 0:03:20.320 --> 0:03:23.840 you get the picture. The water is changing form and 0:03:23.919 --> 0:03:28.200 it's changing place, but it's not leaving the planet. So 0:03:28.400 --> 0:03:32.119 when you hear about things like wasting water, well, it's 0:03:32.120 --> 0:03:35.120 not that the water is going away permanently, but it 0:03:35.200 --> 0:03:38.320 does mean that you are using up water that is 0:03:38.560 --> 0:03:42.480 very important, and it takes a lot of treatment to 0:03:42.600 --> 0:03:46.880 get that water back into a state where people can 0:03:46.920 --> 0:03:49.280 make safe use of it again, so really it's not 0:03:49.360 --> 0:03:52.200 so much of that water has gone away, as now 0:03:52.200 --> 0:03:53.920 we have to do a whole lot of stuff to 0:03:53.960 --> 0:03:58.040 that water in order to use it. Again, about of 0:03:58.200 --> 0:04:01.560 all the water on Earth is in the oceans, and 0:04:01.600 --> 0:04:06.240 that's just plain inconvenient. Ocean water is extremely salty, so 0:04:06.360 --> 0:04:08.520 you can't drink it, you can't use it for irrigation 0:04:08.720 --> 0:04:12.680 unless you put it through a desalination process, which essentially 0:04:12.680 --> 0:04:15.520 means you're pulling the salt out of the water. But 0:04:16.320 --> 0:04:18.880 we'll get into that in some other episode because that's 0:04:18.920 --> 0:04:22.480 an entirely separate topic that requires a lot of discussion. 0:04:22.520 --> 0:04:25.160 Plus I've I've kind of covered it in previous episodes anyway, 0:04:25.560 --> 0:04:28.880 but only three of the water on Earth is freshwater, 0:04:29.360 --> 0:04:32.760 and on some parts of the planet it's really hard 0:04:32.839 --> 0:04:36.559 to come by. Wars are fought over the stuff, which 0:04:37.120 --> 0:04:41.680 isn't a surprise because news flash, in case you weren't aware, 0:04:42.000 --> 0:04:46.120 we need fresh water to survive. Generally speaking, the typical 0:04:46.240 --> 0:04:50.400 human body is six water, and some oregans are much 0:04:50.480 --> 0:04:53.680 higher in water content than others, like the lungs, which 0:04:53.680 --> 0:04:57.159 are about water, so we can only go a few 0:04:57.240 --> 0:05:01.160 days without water before we start to suffer some pretty 0:05:01.200 --> 0:05:06.320 awful effects like death. Water can also carry with it 0:05:06.480 --> 0:05:10.360 some dangerous stuff. Toxins can leach into water, so you 0:05:10.360 --> 0:05:14.120 can have dissolved medals like lead. This has historically been 0:05:14.200 --> 0:05:17.039 an enormous problem and continues to be a challenge to 0:05:17.040 --> 0:05:20.720 this very day in the United States, a country that 0:05:21.000 --> 0:05:23.800 arguably should have solutions in place to deal with this 0:05:23.839 --> 0:05:27.960 sort of thing all the time. We've seen a crisis 0:05:28.520 --> 0:05:31.839 that started really in two thousand fourteen in Flint, Michigan. 0:05:32.240 --> 0:05:33.919 I'll get back to that story at the end of 0:05:33.920 --> 0:05:38.599 this podcast, because it is an important crisis that should 0:05:38.600 --> 0:05:40.960 have been handled or should have never happened in the 0:05:41.040 --> 0:05:44.279 first place, and it's an example of a massive failure 0:05:44.360 --> 0:05:47.640 in leadership because we do have the technology to deal 0:05:47.680 --> 0:05:49.320 with this sort of stuff, so it comes down to 0:05:49.360 --> 0:05:56.000 administration and sadly money. Anyway, water, even fresh water, isn't 0:05:56.040 --> 0:06:01.240 necessarily inherently safe to drink. Water can carry toxins and pathogens, 0:06:01.320 --> 0:06:03.880 and those can have a negative effect on us up 0:06:03.920 --> 0:06:07.680 to and including death depending on the situation, and so 0:06:07.839 --> 0:06:11.359 much of human history, particularly in the era of civilization, 0:06:11.760 --> 0:06:14.320 has had a focus on how to gather water, to 0:06:14.440 --> 0:06:18.159 store it, to distribute it, and how to treat it. Now, 0:06:18.200 --> 0:06:22.400 early on humans seem to have managed fairly well without 0:06:22.800 --> 0:06:27.360 massive problems related to water contamination. Now and then it 0:06:27.400 --> 0:06:30.599 would happen but by and large, humans got pretty good 0:06:30.640 --> 0:06:34.680 at avoiding water that wasn't safe to drink. Our senses 0:06:34.880 --> 0:06:38.520 tell us things such as if the water smells bad 0:06:38.720 --> 0:06:42.599 or tastes bad, that means it probably is bad. And 0:06:42.640 --> 0:06:45.479 that brings up an interesting series of questions about how 0:06:45.600 --> 0:06:49.360 we developed those reactions and senses. I mean, when you 0:06:49.480 --> 0:06:53.920 encounter a bad smell, you know that it's a bad smell. 0:06:53.960 --> 0:06:58.120 But why do our brains interpret it as bad? Why 0:06:58.200 --> 0:07:01.920 do we have that negative reaction? What makes one smell 0:07:02.240 --> 0:07:05.760 a good smell and another one a bad smell. But 0:07:06.640 --> 0:07:09.440 to be fair, those questions and answers are all outside 0:07:09.440 --> 0:07:11.800 the realm of tech stuff. I just find them fascinating. 0:07:12.280 --> 0:07:15.200 In the early eras of human history, we were hunter 0:07:15.320 --> 0:07:19.120 gatherers and nomads, and once we decided, you know, our 0:07:19.160 --> 0:07:21.880 feet were done itching, we wanted to set up shop 0:07:21.920 --> 0:07:26.320 and settle down. New challenges came about, not just regarding 0:07:26.360 --> 0:07:29.440 access to clean, drinkable water, which got to be more 0:07:29.560 --> 0:07:33.600 complicated as humans started to create larger and larger settlements, 0:07:33.640 --> 0:07:36.960 but also what to do with the waste we were generating, 0:07:37.160 --> 0:07:40.840 like the waste water. Contaminating drinking water with waste is 0:07:41.320 --> 0:07:44.160 you know, gross, and a terrible problem to have. It 0:07:44.240 --> 0:07:48.040 leads to awful outbreaks of illness. So humans had to 0:07:48.040 --> 0:07:50.240 start figure out how to deal with all this once 0:07:50.280 --> 0:07:53.960 they began to make permanent settlements and populations began to grow. 0:07:54.240 --> 0:07:58.440 One of the important early techniques for humans, one used 0:07:58.480 --> 0:08:01.920 to the present day, was all about digging a well. 0:08:02.520 --> 0:08:05.000 And this was, you know, important if you didn't have 0:08:05.120 --> 0:08:09.120 access immediately to some body of water like a lake 0:08:09.320 --> 0:08:12.880 or river or stream. But it's a pretty straightforward process. 0:08:13.000 --> 0:08:16.520 So I'm gonna be quick about the whole well digging thing. 0:08:17.040 --> 0:08:19.480 So you got the ground right, and the ground is 0:08:19.520 --> 0:08:22.560 made up of dirt and rocks and dinosaur bones and 0:08:22.680 --> 0:08:25.280 zombies and you know that kind of stuff. The ground 0:08:25.280 --> 0:08:29.040 in most places tends to be porous and permeable to water. 0:08:29.480 --> 0:08:32.959 So as water falls as precipitation, you know, rain or snow, 0:08:33.000 --> 0:08:35.960 and then either just goes into the ground or melts 0:08:36.000 --> 0:08:39.160 and then goes into the ground. It moves down through 0:08:39.440 --> 0:08:43.040 the soil and rocks. It takes up the space that 0:08:43.160 --> 0:08:46.960 is in between particles and continues because of gravity, to 0:08:47.040 --> 0:08:53.040 move downward. Now, some layers in the soil might be impermeable, 0:08:53.280 --> 0:08:55.559 you know, the rocks are less porous. Maybe there's a 0:08:56.400 --> 0:08:59.720 level of clay which is not terribly permeable to water, 0:09:00.200 --> 0:09:03.120 so then water will start to saturate the layers that 0:09:03.160 --> 0:09:06.720 are higher up from that impermeable one, it can't go lower, 0:09:07.000 --> 0:09:10.719 so the water just kind of continues to accumulate and 0:09:10.840 --> 0:09:14.720 saturate the porous ground, and it has nowhere else to go. 0:09:14.800 --> 0:09:17.880 It can't really seep lower down. So if you were 0:09:17.880 --> 0:09:20.880 to look at the ground in a cross section, the 0:09:20.920 --> 0:09:25.000 top layers of dirt and rock would have some water content, 0:09:25.160 --> 0:09:28.040 but not at a point where the ground is saturated. 0:09:28.360 --> 0:09:31.920 At that level, water is essentially being held onto particles 0:09:31.920 --> 0:09:35.800 through molecular attraction, and it's just kind of loosely held 0:09:35.800 --> 0:09:38.880 to the surfaces of rock particles. But as you go lower, 0:09:39.120 --> 0:09:42.760 you would find a greater concentration of water as the 0:09:42.920 --> 0:09:46.760 rocky soil becomes saturated with the stuff, meaning all the 0:09:46.800 --> 0:09:51.679 porous surfaces are full of groundwater. The top layer of 0:09:51.720 --> 0:09:54.400 this saturated zone of rock is what we call the 0:09:54.400 --> 0:09:58.600 water table. It is the top level of the saturated zone. 0:09:58.960 --> 0:10:02.200 It's the upper layer of groundwater. And if you find 0:10:02.200 --> 0:10:05.520 an area of groundwater that readily refills a hole, like 0:10:05.559 --> 0:10:08.000 if you were to dig a hole and you hit groundwater, 0:10:08.559 --> 0:10:10.839 you take the water out, and more water comes in. 0:10:11.440 --> 0:10:16.440 You have found an aquifer. Aquifers are store houses for water. 0:10:16.800 --> 0:10:21.840 Aquifers get refilled or recharged when precipitation hits the ground 0:10:21.880 --> 0:10:24.600 and water soaks into the soil and gradually makes its 0:10:24.600 --> 0:10:28.800 way down to this layer again, so it's constantly being refilled, 0:10:28.880 --> 0:10:33.520 or maybe not constantly regularly being refilled. The water in 0:10:33.559 --> 0:10:37.200 a well will start at around the same level of 0:10:37.240 --> 0:10:39.199 the water table in general, So let's say that the 0:10:39.240 --> 0:10:42.920 water table is ten feet down from the ground surface. 0:10:43.160 --> 0:10:45.440 That means once you hit ten feet as you're digging 0:10:45.480 --> 0:10:48.040 your well, you'll start to see water. You typically would 0:10:48.040 --> 0:10:50.320 dig further down than that so that you would have 0:10:50.360 --> 0:10:54.080 a reservoir of water, but if you were to remove 0:10:54.160 --> 0:10:58.120 water from the well, it would continuously refill to that 0:10:58.440 --> 0:11:02.440 you know, that same level ten feet down from the surface. 0:11:02.920 --> 0:11:06.040 So if you locate an aquifer and you dig down 0:11:06.080 --> 0:11:08.440 far enough and you you know, shore up the sides 0:11:08.520 --> 0:11:11.720 of your hole so that it doesn't collapse in on itself, 0:11:12.160 --> 0:11:14.360 then you've got yourself a well from which you can 0:11:14.400 --> 0:11:16.560 draw water. Now, in the olden days, you would do 0:11:16.600 --> 0:11:18.720 that with like a rope in a bucket, you would 0:11:18.720 --> 0:11:21.360 lower the bucket down, fill it up in the water 0:11:21.600 --> 0:11:23.760 than the well, and then pull the bucket back out. 0:11:24.240 --> 0:11:26.320 And you do that on demand. These days we have 0:11:26.440 --> 0:11:29.520 pumps and filters and stuff, and I'll get into those 0:11:29.559 --> 0:11:32.320 more a bit later. And there's another case I should cover, 0:11:32.840 --> 0:11:38.559 because it is a really cool thing. Some aquifers are confined. Now. 0:11:38.640 --> 0:11:42.480 That means that these aquafers have layers of less porous 0:11:42.559 --> 0:11:47.760 or impermeable rocks or soil, both below them and above them. So, 0:11:47.800 --> 0:11:49.720 in other words, the water you can think of the 0:11:49.720 --> 0:11:53.840 groundwater is flowing. It's flowing through the rocks and soil, 0:11:54.000 --> 0:11:58.280 and sometimes this water flows into areas where the layer 0:11:58.320 --> 0:12:02.120 above is impermeable. So the water didn't just seep straight down. 0:12:02.200 --> 0:12:04.880 It seeped in from some other place, flowed into an 0:12:04.880 --> 0:12:08.360 area where it no longer can move in an upward 0:12:08.440 --> 0:12:11.400 direction as more water is coming in. So this water 0:12:11.480 --> 0:12:15.680 is actually under pressure, you know, like the song by 0:12:16.400 --> 0:12:19.120 Queen and David Bowie. But here's the things that water 0:12:19.360 --> 0:12:23.480 doesn't compress. If you put pressure on water, then that 0:12:23.520 --> 0:12:26.520 water is going to push outward in all directions. This 0:12:26.600 --> 0:12:29.240 makes it different from a gas. You know, gas has 0:12:29.280 --> 0:12:32.800 molecules where you can typically force them closer together, and 0:12:32.920 --> 0:12:35.600 through pressurization you can compress a gas. You can't do 0:12:35.679 --> 0:12:38.440 that with water. Applying pressure to water we can do 0:12:38.480 --> 0:12:41.480 some pretty impressive things. That's what hydraulic systems are all about. 0:12:41.559 --> 0:12:45.400 But let's get back to confined aquifers. So, because this 0:12:45.480 --> 0:12:49.040 type of aquifer is under pressure and the water can't 0:12:49.160 --> 0:12:52.760 escape that confined space due to those non porous rock layers, 0:12:53.120 --> 0:12:56.640 if you drill a well down into that confined aquifer, 0:12:56.840 --> 0:12:59.920 it allows the water an escape route and that result 0:13:00.120 --> 0:13:03.200 in what is called an artesian well. The water in 0:13:03.240 --> 0:13:07.319 an artesian well will rise above the water table line. 0:13:07.400 --> 0:13:09.560 Because there's pressure on that water, it's going to start 0:13:09.640 --> 0:13:13.800 to move up the well. Uh sometimes it will move 0:13:13.920 --> 0:13:16.240 all the way up the well and come out of 0:13:16.280 --> 0:13:19.680 the well entirely. So, if you've got yourself a confined 0:13:19.679 --> 0:13:22.600 aquifer and you dig a well down to it, the 0:13:22.640 --> 0:13:26.079 water can be under enough pressure underground to create a 0:13:26.120 --> 0:13:29.520 constant flow up and out of the well. There are 0:13:29.520 --> 0:13:31.560 a lot of springs that are fed this way. They 0:13:31.559 --> 0:13:33.439 are pretty nifty, and there are a lot of people 0:13:33.960 --> 0:13:37.840 who have pipes that extend down into the ground, and 0:13:37.880 --> 0:13:41.079 there's no electric pump or anything working on those pipes. 0:13:41.320 --> 0:13:44.120 The pipes actually go down into a confined aquifer. So 0:13:44.240 --> 0:13:47.520 just opening up a valve allows that water and escape route, 0:13:47.520 --> 0:13:50.560 and the pressure from the ground itself is pushing the 0:13:50.559 --> 0:13:53.600 water out. And I also need to explain the difference 0:13:53.640 --> 0:13:57.040 between a well and a cistern. A cistern a c 0:13:57.440 --> 0:14:00.600 I s t e r in is a collect system 0:14:00.640 --> 0:14:05.080 that collects rainwater rather than groundwater. So it's a container, 0:14:05.120 --> 0:14:07.760 and sometimes it's one that's actually buried in the ground, 0:14:07.920 --> 0:14:11.040 so that can potentially confuse you if you just were 0:14:11.080 --> 0:14:14.800 to see one. But it's just there to collect the 0:14:14.880 --> 0:14:18.400 runoff of rainwater that feeds in through rain showers, so 0:14:18.440 --> 0:14:21.440 it doesn't pull groundwater up. You're just collecting rainwater before 0:14:21.640 --> 0:14:24.240 it can go into the ground. So that's pretty straightforward. 0:14:24.960 --> 0:14:27.080 Now I want to talk about the physics of getting 0:14:27.080 --> 0:14:30.360 water out of a well and up to us. There 0:14:30.360 --> 0:14:32.840 are a few ways to do this, and one is 0:14:32.880 --> 0:14:36.040 one I mentioned already, a purely mechanical method to lower 0:14:36.080 --> 0:14:38.760 a bucket down into the well and collect water and 0:14:38.800 --> 0:14:41.520 then pull the bucket back out. A lot of classic 0:14:41.560 --> 0:14:43.600 wells you know the kind of I think about when 0:14:43.640 --> 0:14:46.800 I think of the word well. Have a simple pulley 0:14:46.840 --> 0:14:50.200 system that allows you to lower a bucket down into 0:14:50.240 --> 0:14:53.400 the well chamber and fill it up and then pull 0:14:53.480 --> 0:14:55.880 the bucket back out. Pulleys are one of the simplest 0:14:55.920 --> 0:14:59.040 of machines. A pulley is a wheel around which you 0:14:59.120 --> 0:15:02.640 wrap a hope or wire, and the pulley just changes 0:15:02.720 --> 0:15:05.600 the direction of the force you need to use to 0:15:05.720 --> 0:15:08.880 do work. So instead of pulling straight up, you could 0:15:08.880 --> 0:15:14.000 pull down. And typically pulling downward is easier to do 0:15:14.160 --> 0:15:17.720 than pulling straight up, So while you're still lifting the 0:15:17.760 --> 0:15:21.680 same amount of weight, it's easier work to do because 0:15:21.680 --> 0:15:23.840 of the direction of the force you're applying. Now, if 0:15:23.840 --> 0:15:26.160 you add more pulleys to a system, you can actually 0:15:26.200 --> 0:15:29.240 create a mechanical advantage and that makes work easier. But 0:15:29.360 --> 0:15:34.440 that is outside this episode. But what about something like handpumps. 0:15:35.040 --> 0:15:38.040 You've likely seen this in movies or TV shows where 0:15:38.120 --> 0:15:40.920 there's a hand pump for water. Maybe you've seen pictures 0:15:40.920 --> 0:15:43.480 of one, maybe you've even used one. They tend to 0:15:43.520 --> 0:15:46.240 look like a pipe that's sticking out of the ground 0:15:46.400 --> 0:15:48.520 and it has a spout on one side where the 0:15:48.520 --> 0:15:51.400 water comes out, and a pump handle on the other 0:15:51.480 --> 0:15:53.520 that you pump up and down. So you give the 0:15:53.520 --> 0:15:56.000 handle a few pumps and before long water starts coming 0:15:56.040 --> 0:15:59.760 out of the spout. How does that work? This all 0:15:59.800 --> 0:16:05.160 has to do with pressure and using the atmospheric pressure 0:16:06.080 --> 0:16:09.560 to do work for us. So let's remember again, we're 0:16:09.600 --> 0:16:14.040 all under pressure. At sea level. We're under an atmosphere 0:16:14.160 --> 0:16:17.760 of pressure or about fourteen point seven pounds per square inch. 0:16:17.920 --> 0:16:21.200 That's how much the atmosphere is pressing down on us 0:16:21.240 --> 0:16:24.840 at sea level. If we can decrease the pressure that's 0:16:24.880 --> 0:16:29.280 in a tube sticking down into the ground into ground water, 0:16:29.640 --> 0:16:33.040 if we can reduce the air pressure inside that tube 0:16:33.320 --> 0:16:37.800 by introducing a vacuum, water will move up that tube 0:16:37.960 --> 0:16:41.040 because it's an area of lower pressure. It helps if 0:16:41.080 --> 0:16:44.840 you think about the outside pressure, the atmospheric pressure as 0:16:44.880 --> 0:16:49.000 pushing down on the water, and the lower pressure is 0:16:49.080 --> 0:16:52.640 an escape route. So the water moves up the area 0:16:52.760 --> 0:16:58.600 of lower pressure. So we think of it as you know, sucking, 0:16:59.400 --> 0:17:02.120 but that's not really the case. Like like when you're 0:17:02.160 --> 0:17:05.480 drinking from a straw, it's not that you're using suction 0:17:05.600 --> 0:17:09.680 to draw the water up directly. You're reducing the air 0:17:09.720 --> 0:17:13.800 pressure inside the straw, and the atmospheric pressure is forcing 0:17:13.880 --> 0:17:17.479 liquid to go up the straw as a result. So 0:17:17.560 --> 0:17:19.439 really to do this, all we need is a device 0:17:19.560 --> 0:17:23.560 that can lower the pressure inside a tube that extends 0:17:23.600 --> 0:17:26.640 down into the water in order to draw water up somehow. 0:17:27.520 --> 0:17:30.840 But how do you do that If the tube you 0:17:30.920 --> 0:17:33.800 have has a spout at the top right, if it's open, 0:17:34.520 --> 0:17:37.920 then you can't create a vacuum because you have an 0:17:37.960 --> 0:17:42.119 open path to the atmosphere. In general, the secret is 0:17:42.160 --> 0:17:45.359 in a pair of valves and a piston that is 0:17:45.400 --> 0:17:49.199 inside the pump. So if you could use Superman's powers 0:17:49.200 --> 0:17:51.600 of X ray vision and look through a pump, you 0:17:51.640 --> 0:17:55.880 would see that the handle connects to a reciprocating piston. 0:17:56.000 --> 0:17:58.359 So this is a piston that moves up and down 0:17:58.440 --> 0:18:01.720 inside the pump. But the base of this piston wouldn't 0:18:01.720 --> 0:18:05.199 be like a solid fixed disc, you know, like the 0:18:05.200 --> 0:18:08.440 piston you would find in a car engine. Instead, it's 0:18:08.600 --> 0:18:11.560 a disc that's actually on a hinge. It's a valve. 0:18:12.119 --> 0:18:16.920 So when you are forcing the piston downward, the disc 0:18:17.119 --> 0:18:21.560 flips up because the pressure you're you're encountering is pushing 0:18:21.560 --> 0:18:24.479 the disc up. The valve is open and the piston 0:18:24.600 --> 0:18:29.000 is allowed to go down the shaft of this pipe. 0:18:29.600 --> 0:18:33.760 When the piston starts moving up again, the disc flips 0:18:34.160 --> 0:18:38.760 closed because again the pressure causes this to happen, and 0:18:39.119 --> 0:18:43.720 that means that it is sealed everything that's underneath the piston. 0:18:44.240 --> 0:18:46.760 And as the piston draws up, it starts to create 0:18:46.800 --> 0:18:50.800 a vacuum. It's it's lowering the pressure inside the pipe. 0:18:51.000 --> 0:18:53.080 So every time the piston comes up to the top 0:18:53.119 --> 0:18:56.480 of its stroke and starts to move down again, the 0:18:56.600 --> 0:19:01.680 valve opens and allows are to pass past it, and 0:19:01.760 --> 0:19:05.360 as it gets to the bottom, it closes and creates suction. 0:19:05.440 --> 0:19:07.680 It does this over and over and over again as 0:19:07.720 --> 0:19:10.960 it starts to draw water upward. Now at the other 0:19:11.160 --> 0:19:16.600 end of the pump leading down into the well, you 0:19:16.680 --> 0:19:20.119 have a second valve. This is called the foot valve. 0:19:20.240 --> 0:19:23.800 This one's very important because I just mentioned that when 0:19:23.800 --> 0:19:28.359 the piston is going down, the piston valve opens. Well, 0:19:28.600 --> 0:19:30.480 if that were all, if that was the only valve 0:19:30.520 --> 0:19:32.960 in the system, then the water would just fall away 0:19:33.000 --> 0:19:36.439 because you've just you know, allowed the air pressure to 0:19:36.800 --> 0:19:40.520 equalize again. So the air pressure, the atmospheric pressure is 0:19:40.560 --> 0:19:43.200 no longer pushing water up the pipe. So this foot 0:19:43.280 --> 0:19:47.399 valve when the piston is coming down, is closed, so 0:19:47.480 --> 0:19:51.240 it prevents water from going back down the pipe. And 0:19:51.440 --> 0:19:55.080 when the piston is moving up again, when the piston 0:19:55.400 --> 0:19:59.600 valve is closed, the foot valve opens, allowing access to 0:19:59.640 --> 0:20:02.359 the water that's in the well. So it's these two 0:20:02.440 --> 0:20:05.199 valves working together as the piston is moving up and 0:20:05.240 --> 0:20:09.520 down that create the ability for the atmospheric pressure to 0:20:09.640 --> 0:20:13.760 push water down, pushing it up the pipe. So every 0:20:13.800 --> 0:20:16.520 time the piston completes its upward journey and switches direction, 0:20:16.600 --> 0:20:20.160 the piston valve opens, the foot valve closes, water moves 0:20:20.160 --> 0:20:22.760 into the pump. It can't flow back down into the 0:20:22.760 --> 0:20:25.960 well because then the foot valve closes. It keeps that 0:20:26.040 --> 0:20:30.359 water steady, maintains the vacuum that's in place below the valve, 0:20:30.760 --> 0:20:33.600 and then the piston valve opens, allowing the piston to 0:20:33.640 --> 0:20:36.840 travel back down into the water that has collected inside 0:20:36.840 --> 0:20:40.119 the pump. Then, as the piston begins to change direction 0:20:40.119 --> 0:20:44.320 and move upward, the piston valve closes again that traps 0:20:44.359 --> 0:20:46.760 the water above it. It essentially is like a bucket, right, 0:20:46.920 --> 0:20:49.760 It has just trapped the water that had already entered 0:20:49.760 --> 0:20:52.359 into the pump and it lifts it as the piston 0:20:52.440 --> 0:20:56.360 moves up, So you essentially are using suction the same 0:20:56.400 --> 0:20:58.080 way you would drink out of a glass, and then 0:20:58.080 --> 0:21:00.280 at the very very end of it using kind of 0:21:00.320 --> 0:21:03.359 a bucket method to pull the water up to the spout. 0:21:03.480 --> 0:21:06.840 It's pretty nifty. Now, when we come back, I'll talk 0:21:06.920 --> 0:21:10.040 about centrifugal pumps and then we'll move on to more 0:21:10.080 --> 0:21:13.960 complicated means of getting water to people. But first let's 0:21:13.960 --> 0:21:24.720 take a quick break. One thing I did not get 0:21:24.760 --> 0:21:27.080 to when I was talking about handpumps a bit earlier 0:21:27.119 --> 0:21:32.440 is that since it does work on decreasing the air 0:21:32.480 --> 0:21:37.120 pressure in a tube and then relying on atmospheric pressure 0:21:37.200 --> 0:21:40.159 to do some work and push the water up the tube, 0:21:40.440 --> 0:21:43.399 there's actually a limit to how far you can pump 0:21:43.600 --> 0:21:48.520 water vertically. If you're depending on atmospheric pressure to force 0:21:48.600 --> 0:21:52.160 water up a vertical distance of pipe, you can lift 0:21:52.200 --> 0:21:56.040 water a maximum of ten point three meters, and that 0:21:56.200 --> 0:22:00.520 is assuming you've got a perfect vacuum and that your 0:22:00.520 --> 0:22:02.960 pump is at sea level, and you can ignore some 0:22:03.040 --> 0:22:06.720 other realities of physics like friction and stuff. In practical terms, 0:22:07.200 --> 0:22:09.080 it means that ten point three is something you're never 0:22:09.160 --> 0:22:11.399 going to achieve. It's going to be more like seven 0:22:11.440 --> 0:22:15.159 to eight meters of vertical space. That's how far you 0:22:15.160 --> 0:22:18.960 can pump liquid. Because while this air pressure thing does work, 0:22:19.359 --> 0:22:22.000 you can't just get rid of the concept of gravity. 0:22:22.440 --> 0:22:25.800 Water has weight to it. So let's say you've dug 0:22:25.960 --> 0:22:30.000 way down, like fifty feet down, and you finally hit 0:22:30.000 --> 0:22:33.119 the water table and you install a hand pump, and 0:22:33.400 --> 0:22:35.920 you pump that hand pump over and over again until 0:22:35.920 --> 0:22:38.160 you're ready to collapse, but no water is coming out. 0:22:38.200 --> 0:22:41.640 So what's actually happening here. Well, while the pump lowers 0:22:41.680 --> 0:22:44.480 the air pressure in the pipe leading down to the well, 0:22:44.640 --> 0:22:48.160 and the atmospheric pressure is pushing against the water even 0:22:48.200 --> 0:22:51.160 as far down as fifty feet, it does cause water 0:22:51.240 --> 0:22:53.919 to move up the pipe, but that water still has weight, 0:22:54.200 --> 0:22:58.119 and eventually, with enough verticality there, you've got enough water. 0:22:58.320 --> 0:23:00.879 The weight of the column of water or ends up 0:23:00.920 --> 0:23:04.399 being equal to the force that the air pressure is 0:23:04.520 --> 0:23:07.240 applying to that water, and it's not going to go 0:23:07.320 --> 0:23:11.239 any higher. Using this pumping method. It's kind of like 0:23:11.280 --> 0:23:14.679 a set of scales that achieves balance. Even if you 0:23:14.680 --> 0:23:17.879 could create a perfect vacuum, the water would not go 0:23:18.080 --> 0:23:20.600 as high as you need if it were fifty ft down. 0:23:21.359 --> 0:23:25.400 Centrifugal pumps work in a different way from hand pumps, 0:23:25.400 --> 0:23:28.919 but ultimately we'll have to deal with the same limitations 0:23:28.920 --> 0:23:32.600 of physics. So with a centrifugal pump, you've got a 0:23:32.640 --> 0:23:35.680 pipe that leads down into the water. This is where 0:23:35.680 --> 0:23:38.440 water will enter the pump from the well, and it's 0:23:38.480 --> 0:23:43.000 called an inlet. It's pretty clever, right. There is a 0:23:43.119 --> 0:23:46.400 valve at the end of that pipe that sits inside 0:23:46.400 --> 0:23:49.119 the well itself, so it's submerged in the well water. 0:23:49.600 --> 0:23:52.280 This is the foot valve. It allows the water to 0:23:52.400 --> 0:23:55.880 flow into the pipe, but prevents it from flowing back 0:23:55.920 --> 0:23:59.440 out again. That is going to be important in order 0:23:59.520 --> 0:24:02.080 to make this whole system work. So when the pump 0:24:02.160 --> 0:24:05.919 is on, the valve opens and the water can flow 0:24:06.160 --> 0:24:09.840 from the well into the inlet. When the pump is off, 0:24:09.840 --> 0:24:13.120 the valve closes and prevents any water that's already in 0:24:13.160 --> 0:24:17.200 the pipe and the pump from draining back out again. 0:24:17.560 --> 0:24:21.399 There's also a pipe that leads out from the pump. 0:24:21.600 --> 0:24:24.360 This is where the water will flow out while you're 0:24:24.400 --> 0:24:27.959 pumping it. It's the outlet and discharge nozzle. This is 0:24:28.240 --> 0:24:30.960 the part of the pump that leads into the plumbing 0:24:31.040 --> 0:24:34.280 system of a house. The heart of the pump is 0:24:34.480 --> 0:24:38.840 a circular or really actually a spiral shaped chamber called 0:24:38.880 --> 0:24:42.479 the volute casing. And a volute is a spiral shape. 0:24:42.720 --> 0:24:46.640 It increases in size as you go around. And so 0:24:46.880 --> 0:24:49.479 a volute casing looks a little bit like kind of 0:24:49.480 --> 0:24:53.120 like a conk shell. And there's an electric motor that 0:24:53.200 --> 0:24:56.600 connects to a rotating shaft, and that shaft connects to 0:24:56.680 --> 0:25:00.240 a device called an impeller, and that sits inside the 0:25:00.280 --> 0:25:04.959 volute chamber. And impeller is designed to move fluid. And 0:25:05.000 --> 0:25:07.560 it looks kind of like a water wheel in that 0:25:07.640 --> 0:25:09.760 it is sort of wheel shaped, and it has these 0:25:09.760 --> 0:25:13.560 sort of curved fins. They're actually called veins V A, 0:25:13.960 --> 0:25:18.160 N E S. And these veins push water. As the 0:25:18.200 --> 0:25:22.679 impeller rotates in a single direction, it forces water to 0:25:22.840 --> 0:25:26.640 follow the rotating path. As also an interesting note here, 0:25:26.960 --> 0:25:30.000 the curve fins look kind of like scoops, so you 0:25:30.080 --> 0:25:33.760 might first think they are scooping water, that they're forcing 0:25:33.760 --> 0:25:36.480 water out kind of like a paddle and pushing water 0:25:36.560 --> 0:25:38.760 that way, but in fact that's not what's happening. The 0:25:38.880 --> 0:25:43.080 rotating impeller is creating friction to cause a rotational motion 0:25:43.240 --> 0:25:47.000 with the water, throwing it outward toward the edges of 0:25:47.040 --> 0:25:50.639 the volute chamber. So the water is following the smoothest path, 0:25:51.080 --> 0:25:54.440 and the fins actually curve away from the motion of rotation, 0:25:54.520 --> 0:25:57.200 not towards the motion of rotation, so there's no scooping 0:25:57.240 --> 0:25:59.919 going on with these things. So the water comes in 0:26:00.080 --> 0:26:03.320 through the inlet towards the center of the impeller. It comes, 0:26:03.320 --> 0:26:05.679 you know, kind of head on to the impeller, and 0:26:05.720 --> 0:26:08.439 the motorized impeller pushes the water to the edge of 0:26:08.440 --> 0:26:11.960 the volute casing through centrifugal force. The water in the 0:26:12.000 --> 0:26:16.320 casing follows the curve of the spiral outward, so it 0:26:16.400 --> 0:26:19.320 hits the wall and then just starts to move along 0:26:19.359 --> 0:26:23.320 with the rotational force moving outward. The pressure increases as 0:26:23.359 --> 0:26:25.600 a result of this, will get more into pressure in 0:26:25.600 --> 0:26:30.359 a little bit and that eventually goes to the outlet 0:26:30.760 --> 0:26:34.359 from the far end of the volute casing. There's also 0:26:34.440 --> 0:26:37.359 usually a cut off that prevents the water from just 0:26:37.520 --> 0:26:41.520 circulating in the casing over and over again. The diameter 0:26:41.680 --> 0:26:45.160 of the impeller and the speed of the impeller's rotation 0:26:45.240 --> 0:26:47.320 and the density of the fluid, because you know, these 0:26:47.320 --> 0:26:50.160 centrifugal pumps are used to move all sorts of fluids around, 0:26:50.160 --> 0:26:53.720 not just water. That determines how much force the pump 0:26:53.800 --> 0:26:56.920 is imparting to whatever fluid it happens to be pumping. 0:26:57.840 --> 0:27:03.119 This process creates the lower pressure inside the pipe, and 0:27:03.160 --> 0:27:05.920 so while the centrifugal pump looks a lot different from 0:27:05.920 --> 0:27:09.040 a hand pump, it's ultimately relying on the same force 0:27:09.119 --> 0:27:12.040 to do a lot of the work that atmospheric pressure 0:27:12.080 --> 0:27:15.040 on the water that's in the well. But the centrifugal 0:27:15.119 --> 0:27:18.440 pump doesn't have the dual valve system that the hand 0:27:18.480 --> 0:27:22.480 pumps have. So getting one going means that first you 0:27:22.520 --> 0:27:27.040 have to prime the pump, and that means submerging the 0:27:27.240 --> 0:27:30.240 entire system from the pump all the way down into 0:27:30.240 --> 0:27:32.480 the well with water. So you've got to make sure 0:27:32.520 --> 0:27:35.800 that there's water going through the pump all the way 0:27:35.840 --> 0:27:39.560 down the line into the well before the pump can 0:27:39.600 --> 0:27:42.600 start to pull water in. Uh. This is so that 0:27:42.800 --> 0:27:46.840 it can create that vacuum for the lower pressure for 0:27:47.000 --> 0:27:50.159 atmosphere pressure to push water. You know, to continuously feed 0:27:50.200 --> 0:27:54.439 the pump and uh that valve at the foot of 0:27:54.480 --> 0:27:57.440 the inlet pipe is what keeps the water from flowing 0:27:57.520 --> 0:28:00.199 out into the well while you're trying to get this 0:28:00.280 --> 0:28:02.879 to work. And if the supply of water to the 0:28:02.920 --> 0:28:07.440 volut casing begins to diminish, you might introduce air bubbles, 0:28:07.480 --> 0:28:10.560 and that is bad news. The air bubbles that can 0:28:10.600 --> 0:28:13.399 travel to the impeller, they can collapse its speeds faster 0:28:13.520 --> 0:28:17.560 than sound, and those implosions can damage the impeller. This 0:28:17.640 --> 0:28:21.640 is called cavitation. It's really bad news for pumps. Similar 0:28:21.680 --> 0:28:24.880 to the centrifugal pump is the jet pump. The jet 0:28:24.880 --> 0:28:28.440 pump also uses an impeller, but otherwise it's a little 0:28:28.440 --> 0:28:33.119 bit different in design. The impeller moves water called drive 0:28:33.359 --> 0:28:36.800 water through a path in the pump that loops back 0:28:37.400 --> 0:28:40.800 to point at the impeller. So UH, at the end 0:28:40.840 --> 0:28:44.800 of this loop, the path that leads back to the impeller, 0:28:44.840 --> 0:28:49.040 there's a narrow orifice, there's a jet and water can't 0:28:49.080 --> 0:28:52.360 be compressed, right, So if it can't be compressed to 0:28:52.440 --> 0:28:55.600 fit through this narrow path, then in order for the 0:28:55.600 --> 0:28:58.040 water to move through it actually has to pick up speed. 0:28:59.080 --> 0:29:03.040 As it picks up speed as velocity increases, pressure decreases. 0:29:04.000 --> 0:29:05.960 This is kind of similar to if you have a 0:29:05.960 --> 0:29:08.160 a hose and you put your thumb over the end 0:29:08.160 --> 0:29:12.160 of the hose. You have UH increased the velocity of 0:29:12.200 --> 0:29:15.080 the water coming out, but you've actually decreased the pressure. 0:29:16.000 --> 0:29:19.720 But this whole process creates a vacuum that helps pull 0:29:19.880 --> 0:29:23.360 more water from the well are As we've pointed out, 0:29:23.400 --> 0:29:25.520 it doesn't really pull the water so much as it 0:29:25.840 --> 0:29:29.239 decreases the pressure, so atmospheric pressure does the job on 0:29:29.320 --> 0:29:32.600 the groundwater on the other side of the jet UH 0:29:32.880 --> 0:29:35.400 is what is called a venturi tube. This is a 0:29:35.400 --> 0:29:39.040 tube that increases in diameter, so it gets bigger on 0:29:39.080 --> 0:29:42.600 the other side, and as diameter increases, the speed of 0:29:42.640 --> 0:29:45.240 the water will decrease, but the pressure of the water 0:29:45.360 --> 0:29:49.240 increases and the drive water and well water end up combining. 0:29:49.320 --> 0:29:51.920 They are at a high enough pressure to pump into 0:29:51.960 --> 0:29:56.080 the plumbing system. And this approach still is reliant on 0:29:56.200 --> 0:29:58.840 that atmospheric pressure, so again it only works down to 0:29:58.880 --> 0:30:02.680 a certain depth. But what happens if the water in 0:30:02.720 --> 0:30:05.560 your area is at a lower level, If the water 0:30:05.640 --> 0:30:10.360 table is further down than what you can achieve by 0:30:10.360 --> 0:30:14.640 relying on atmospheric pressure well to pump water below that 0:30:14.800 --> 0:30:18.000 ten point three meters, and again that's the ideal that 0:30:18.040 --> 0:30:21.320 will never achieve. Engineers had to get really creative. There 0:30:21.360 --> 0:30:25.000 are two pipe systems that do this. One pipe is 0:30:25.040 --> 0:30:28.280 the inlet pipe. This is the one that will ultimately 0:30:28.360 --> 0:30:31.400 draw water from the well and supply it to the 0:30:31.440 --> 0:30:34.240 house or building that you're using. And there is a 0:30:34.240 --> 0:30:36.280 foot valve at the end of this so again it 0:30:36.360 --> 0:30:41.040 prevents water from escaping once it enters the pipe. And 0:30:41.080 --> 0:30:43.080 this pipe goes all the way up to the pump 0:30:43.320 --> 0:30:46.640 that is on the ground. It's it's not buried or anything. 0:30:46.640 --> 0:30:51.840 It's right up there. And joining this pipe through a 0:30:51.880 --> 0:30:56.360 special jet joint is a second pipe. This pipe comes 0:30:56.520 --> 0:30:59.240 from the pump, So the second pipe comes out of 0:30:59.240 --> 0:31:02.040 the pump, extend down into the ground to join the 0:31:02.080 --> 0:31:06.520 inlet pipe through this jet joint a little further up 0:31:06.600 --> 0:31:11.440 the pipe's length, and this joint is constructed so that 0:31:11.480 --> 0:31:14.960 the jet is moving water from this second pipe to 0:31:15.160 --> 0:31:19.000 shoot up the first pipe toward the direction of the pump. 0:31:19.120 --> 0:31:21.760 So the jet is down inside the well in this 0:31:21.840 --> 0:31:24.240 version of the pump, but the impeller is still up 0:31:24.240 --> 0:31:27.880 at the pump on the ground. So what's happening is 0:31:28.080 --> 0:31:31.000 both these pipes and the pump are full of water. Okay, 0:31:31.040 --> 0:31:34.479 you've got a full system of water here. It's almost 0:31:34.560 --> 0:31:37.840 like a closed system. It's not really closed because you know, 0:31:37.880 --> 0:31:39.840 we have an outlet pipe with the pump, but let's 0:31:39.840 --> 0:31:43.160 ignore that for now. When you turn on the pump, 0:31:43.640 --> 0:31:46.880 the motor begins to spend the impeller, and the impeller 0:31:47.000 --> 0:31:51.840 forces water down the second pipe, which then moves through 0:31:51.920 --> 0:31:55.720 this jet before joining up with the first pipe, and 0:31:55.840 --> 0:31:58.080 the water as it moves through the jet picks up 0:31:58.160 --> 0:32:02.520 velocity and it lowers the pressure. This lower pressure draws 0:32:02.600 --> 0:32:05.680 water from the well up the inlet, so this part 0:32:05.760 --> 0:32:08.840 is still using atmospheric pressure, but the whole assembly is 0:32:09.040 --> 0:32:12.320 down inside the well, so it's not lifting the water 0:32:12.480 --> 0:32:15.800 very far. The drive water from the pump and the 0:32:15.840 --> 0:32:19.800 well water then pass through a venturi tube, and that 0:32:20.000 --> 0:32:23.920 increase in diameter decreases the water velocity but increases the 0:32:23.960 --> 0:32:27.840 water pressure. And it's that increase in water pressure that 0:32:28.000 --> 0:32:31.160 drives the water up further than it would go if 0:32:31.160 --> 0:32:34.360 we were just relying on atmospheric pressure to do the job. 0:32:34.800 --> 0:32:38.880 The high water pressure inside the tube moves the water 0:32:39.160 --> 0:32:42.680 up the inlet pipe into the pump and then ultimately 0:32:42.840 --> 0:32:45.880 through the plumbing system. So this pump uses the trick 0:32:45.920 --> 0:32:48.880 of lowering pressure inside the pipe to draw up water 0:32:49.160 --> 0:32:53.480 to a certain elevation. Then, through increasing the water pressure 0:32:53.520 --> 0:32:57.840 inside the pipe, lifts it or pushes it further up 0:32:58.000 --> 0:33:01.240 to the pump. This system can work with wells that 0:33:01.280 --> 0:33:04.200 are much deeper than shallow ones, though the further down 0:33:04.240 --> 0:33:07.680 the water is, the less efficient the system will be. Finally, 0:33:07.760 --> 0:33:10.640 we've got submersible pumps. Now, these are pumps that are 0:33:10.680 --> 0:33:13.520 actually in the water of the well itself, and rather 0:33:13.560 --> 0:33:16.760 than lifting water, they are pushing it up the pipe. 0:33:16.960 --> 0:33:19.960 They're also used for deeper wells. These pumps use a 0:33:20.000 --> 0:33:23.360 series of impellers that are separated by diffusers. Uh just 0:33:23.480 --> 0:33:26.080 like the tubes we're talking about before. These lower the 0:33:26.080 --> 0:33:28.640 speed of the water, but they increase the water pressure 0:33:29.200 --> 0:33:32.000 further up the chain, and they do that by increasing 0:33:32.000 --> 0:33:34.680 the diameter of the pathway that the water is following. 0:33:34.960 --> 0:33:38.600 So the water moves through a series of impellers and 0:33:38.680 --> 0:33:42.160 diffusers over and over again, with the water pressure building 0:33:42.280 --> 0:33:45.240 along the way, and that ends up creating the pressure 0:33:45.280 --> 0:33:48.760 needed to deliver the water up the well and to 0:33:49.120 --> 0:33:54.440 a home's plumbing system. One other common component of well 0:33:54.800 --> 0:33:58.800 systems know well water that is supplying homes is a 0:33:58.840 --> 0:34:03.320 pressure tank. Water from the pump will enter a pressure 0:34:03.360 --> 0:34:07.400 tank first before going through the home's plumbing system, and 0:34:07.440 --> 0:34:11.399 as water fills the tank, the pressure inside the tank increases. 0:34:11.719 --> 0:34:14.880 The pump has a sensor connected to this tank and 0:34:14.920 --> 0:34:17.560 there's a cut off value once a certain level of 0:34:17.560 --> 0:34:21.520 pressure is achieved, and at that point the pump shuts off. 0:34:22.000 --> 0:34:24.080 So when you turn on a faucet in a house 0:34:24.120 --> 0:34:27.640 that's supplied with well water, the water actually first comes 0:34:27.680 --> 0:34:31.240 from the pressure tank and the pump will stay off 0:34:31.560 --> 0:34:35.440 unless the pressure in that tank dips below a certain threshold. 0:34:35.840 --> 0:34:38.880 At that point, the pump will kick on and begin 0:34:39.000 --> 0:34:42.000 to resupply the pressure tank with water. Now, the reason 0:34:42.040 --> 0:34:45.080 for the pressure tank is that it decreases the number 0:34:45.080 --> 0:34:47.600 of times the pump has to cycle on and off, 0:34:47.640 --> 0:34:50.359 which helps cut down on wear and tear. There are 0:34:50.440 --> 0:34:53.800 usually some other components that are part of a well system, 0:34:53.920 --> 0:34:56.200 and these are meant to treat the water to remove 0:34:56.239 --> 0:35:00.800 stuff like minerals and organic material and sediment from your water. 0:35:01.160 --> 0:35:04.000 So a water softener is a type of device that 0:35:04.080 --> 0:35:07.320 does that. It's meant to treat so called hard water. 0:35:07.640 --> 0:35:12.920 Hard water contains high concentrations of minerals like magnesium and calcium. 0:35:12.960 --> 0:35:15.879 These are not toxic or anything like that, but they 0:35:15.880 --> 0:35:20.800 can deposit minerals on stuff like on shower tiles. For example, 0:35:20.960 --> 0:35:23.480 I actually have some issues with hard water at my house, 0:35:23.520 --> 0:35:26.040 so I have to scrub my tubs and sinks and 0:35:26.080 --> 0:35:31.600 showers fairly frequently to prevent build up. Water softeners combine 0:35:31.640 --> 0:35:34.640 a tank filled with resin beads and a brian tank 0:35:34.640 --> 0:35:37.560 that you typically have to fill with potassium chloride pellets 0:35:37.640 --> 0:35:41.160 or salt pellets on occasion. So incoming water moves through 0:35:41.200 --> 0:35:44.320 these resin beads, and the resin beads carry a negative 0:35:44.400 --> 0:35:48.200 charge and attract positively charged minerals that are in the water. 0:35:48.719 --> 0:35:53.200 So the minerals deposit to these you know, resin beats. 0:35:53.200 --> 0:35:55.799 They stick to the resin beads, and it allows the 0:35:55.920 --> 0:36:00.560 neutral y charged water to flow through and enter your plumbing. Now, 0:36:00.560 --> 0:36:04.640 eventually the beads attract enough minerals that the software needs 0:36:04.680 --> 0:36:08.240 to be quote unquote regenerated, at which point water flows 0:36:08.280 --> 0:36:11.120 into the brine tank. It creates a brine, and then 0:36:11.120 --> 0:36:15.080 the brine moves through the softener tank. The salty water 0:36:15.520 --> 0:36:19.680 washes the mineral deposits off of the beads. The wastewater 0:36:20.080 --> 0:36:23.120 well then flush down a discharge pipe, and then the 0:36:23.120 --> 0:36:25.480 softerer tank is ready to go again, and you would 0:36:25.480 --> 0:36:29.080 have to occasionally refill the brine tank with pellets on 0:36:29.120 --> 0:36:31.799 a fairly regular basis. How regular would depend on how 0:36:31.880 --> 0:36:34.960 much water you go through. There are other types of 0:36:35.000 --> 0:36:38.400 filtration systems that will remove specific metals and minerals and 0:36:38.440 --> 0:36:42.759 particulates from the water, like iron filtration systems. There's also 0:36:42.840 --> 0:36:45.920 systems that use ultraviolet light to kill off bacteria in 0:36:45.960 --> 0:36:48.719 the water. Actually technically doesn't so much kill off the 0:36:48.760 --> 0:36:53.839 bacteria as it renders the bacteria incapable of replicating. There 0:36:53.840 --> 0:36:57.520 are others that are designed to remove mercury, lead, nickel, 0:36:57.840 --> 0:37:00.280 other metals, as well as those designed to just filter 0:37:00.320 --> 0:37:03.319 out sediment or or getting materials in general. When we 0:37:03.360 --> 0:37:05.879 come back, we'll move away from wells and talk about 0:37:06.000 --> 0:37:17.080 municipal water systems. But first let's take another quick break. Okay, 0:37:17.120 --> 0:37:20.120 so a well might supply a house or a small 0:37:20.160 --> 0:37:23.440 community with water, but what about big cities. These can 0:37:23.520 --> 0:37:26.880 sometimes share some you know, similar elements with well water systems, 0:37:26.920 --> 0:37:30.760 but due to scale, we do require a different approach. 0:37:30.880 --> 0:37:33.840 So you've got to look at the water systems for 0:37:33.920 --> 0:37:38.640 cities as a group of stages and systems. First, you 0:37:38.640 --> 0:37:41.080 have to have a source for your water. Now, that 0:37:41.160 --> 0:37:44.200 could be an aquifer, it could be a lake, It 0:37:44.200 --> 0:37:46.880 could be a river or a stream or some combination 0:37:46.920 --> 0:37:50.160 of these. This water has to go through an extensive 0:37:50.200 --> 0:37:54.200 treatment process to remove anything harmful or unpleasant and make 0:37:54.200 --> 0:37:57.400 the water safe for consumption. More on that in a moment. 0:37:57.719 --> 0:37:59.799 And then the treated water has to go through a 0:37:59.840 --> 0:38:03.920 water distribution system, so pipes and pumps that connect us 0:38:03.920 --> 0:38:07.200 to our water supply, including things like water mains, and 0:38:07.280 --> 0:38:10.480 that provides the water pressure needed to actually move water 0:38:10.560 --> 0:38:13.920 through the system and out our taps and showers and 0:38:14.040 --> 0:38:17.680 washing machines and whatnot. Then you've got a wastewater system. 0:38:17.719 --> 0:38:19.920 I'm not going to really cover those in this episode, 0:38:19.920 --> 0:38:23.280 but the wastewater systems purposes to collect the used water 0:38:23.440 --> 0:38:27.120 and transport it to a wastewater water treatment facility which 0:38:27.120 --> 0:38:30.000 will remove as much contaminants from the wastewater as possible. 0:38:30.280 --> 0:38:31.960 You know, if we think of this a sewer water 0:38:32.719 --> 0:38:36.000 and that water should then be safe to return to 0:38:36.040 --> 0:38:40.400 the environment without contaminating stuff, you know, like your water supply. 0:38:40.520 --> 0:38:43.880 You don't want contaminated water to sink into the ground 0:38:44.320 --> 0:38:47.239 and then become part of the groundwater. You've just major 0:38:47.760 --> 0:38:51.560 drinking water contaminated if you do that. There are also 0:38:51.640 --> 0:38:55.520 stormwater systems that are designed to channel rainwater or snow 0:38:55.560 --> 0:38:58.800 melt away from you know, streets and homes and stuff. 0:38:59.440 --> 0:39:02.439 These systems are integral to prevent flooding, and they move 0:39:02.480 --> 0:39:05.840 water away from the infrastructure of our cities and towns 0:39:06.120 --> 0:39:09.759 and move it back toward the environment like rivers and lakes. 0:39:09.800 --> 0:39:13.239 That can also introduce contaminants. That's another issue, and again 0:39:13.280 --> 0:39:14.759 I'm not really gonna be able to go into that. 0:39:14.840 --> 0:39:18.680 I'm already running fairly along with this episode. So let's 0:39:18.760 --> 0:39:22.000 go through the process of water treatment. You've got your 0:39:22.000 --> 0:39:24.560 water source. So let's say in our example, it's a 0:39:24.640 --> 0:39:28.279 lake and you are transporting water from the lake to 0:39:28.320 --> 0:39:31.960 a water treatment facility. Let's say You've built massive pipes 0:39:32.000 --> 0:39:35.440 and pumps that pump water from the lake into a 0:39:35.440 --> 0:39:40.840 water treatment plant. The first stage is called coagulation and flocculation. 0:39:41.560 --> 0:39:44.239 This is the first stage of removing stuff that we 0:39:44.320 --> 0:39:48.359 don't want in our water, like sediment, bacteria, and you know, 0:39:48.480 --> 0:39:50.239 other stuff that could be floating around in a lake, 0:39:50.320 --> 0:39:53.080 like you know, bits of wood or other organic materials. 0:39:54.080 --> 0:39:57.400 Incoming water from the lake will mix with chemicals like 0:39:57.520 --> 0:40:02.200 ferric chloride or aluminum sulfate, and these chemicals are called coagulants. 0:40:02.200 --> 0:40:05.520 They will congeal with the suspended solids that are in 0:40:05.560 --> 0:40:08.719 the water, and it all comes down to again having 0:40:08.719 --> 0:40:12.279 an opposite charge. The coagulants have the opposite charge of 0:40:12.440 --> 0:40:16.520 the sediments, so they kind of bond to each other. 0:40:16.560 --> 0:40:19.720 They glom onto each other because those opposite charges are 0:40:19.760 --> 0:40:25.080 attracting one another. The mix of coagulants and water then 0:40:25.320 --> 0:40:30.560 moves into what are called flocculation basins, which is what 0:40:30.719 --> 0:40:33.160 a pair of words I mean. Try it, Just say it, 0:40:33.239 --> 0:40:38.160 floculation basin. It's it feels great. Here the water and 0:40:38.239 --> 0:40:43.520 coagulants mixed together. Slowly, the coagulants begin to kind of 0:40:43.520 --> 0:40:46.840 glom onto each other and grow larger. Through this process, 0:40:46.880 --> 0:40:52.000 they form what are called flock particles. Essentially, they're beginning 0:40:52.000 --> 0:40:55.160 to just kind of you know, concentrate, and eventually, once 0:40:55.239 --> 0:40:59.719 a certain quality of water is reached, this mixture will 0:40:59.760 --> 0:41:03.800 move into another section, which could take one of two 0:41:04.200 --> 0:41:09.120 different forms. So one of those forms is as sedimentation basin, 0:41:09.200 --> 0:41:11.839 and in fact, the sedimentation process is kind of what 0:41:11.880 --> 0:41:15.400 we call this part of the whole system. The purpose 0:41:15.480 --> 0:41:18.400 of this basin is to allow those flock particles to 0:41:18.560 --> 0:41:22.839 sink down to the bottom of this vessel, and they 0:41:22.920 --> 0:41:27.560 kind of form a nasty sludge. That sledge is removed 0:41:27.600 --> 0:41:30.080 from the tanks through special pipes near the bottom and 0:41:30.120 --> 0:41:32.760 then dumped in a landfill or something along those lines. 0:41:33.160 --> 0:41:36.200 The water at the top of the sedimentation basin is 0:41:36.200 --> 0:41:39.239 the cleanest, so the closer yard to the surface, the 0:41:39.239 --> 0:41:42.359 cleaner the water, and that water is allowed to move 0:41:42.400 --> 0:41:45.800 over to the next phase. And in this version we 0:41:45.840 --> 0:41:49.840 would take water from the top. Now, the reason I 0:41:49.880 --> 0:41:52.960 say that is to contrast it with the alternative method, 0:41:53.560 --> 0:41:58.479 and that is called a floatation basin, a dissolved air 0:41:58.760 --> 0:42:04.280 floatation basin. So here you pipe air into the bottom 0:42:04.480 --> 0:42:06.480 of the tank. You have like little pipes with holes 0:42:06.480 --> 0:42:09.680 in it, and you shoot air through those pipes and 0:42:09.719 --> 0:42:12.160 the holes allow bubbles to come in through the tank. 0:42:12.560 --> 0:42:15.520 Those bubbles flow up through the tank to go to 0:42:15.560 --> 0:42:18.120 the surface and along the way they push the flock 0:42:18.280 --> 0:42:21.279 particles up to the top of the tank and then 0:42:21.560 --> 0:42:25.240 you can use a sweeping arm to kind of gather 0:42:25.360 --> 0:42:29.080 those flock particles together for collection. So in this version, 0:42:29.320 --> 0:42:32.440 the cleanness water is actually at the bottom of the tank, 0:42:32.640 --> 0:42:35.960 not the top, so we would have a pipe towards 0:42:36.000 --> 0:42:38.400 the bottom of the tank that we would draw water 0:42:38.560 --> 0:42:41.120 from to go into the next part of the system. 0:42:41.160 --> 0:42:43.640 Either way, the water coming out of this part of 0:42:43.640 --> 0:42:47.120 the phase will then go through a series of weirs 0:42:47.280 --> 0:42:50.319 or w e I R s. That's a type of 0:42:50.400 --> 0:42:53.840 low dam and it's really just meant to change the 0:42:53.880 --> 0:42:57.919 flow characteristics of water. The water then moves on to filtration. 0:42:58.200 --> 0:43:01.120 Here the water will enter into a basin that has 0:43:01.160 --> 0:43:03.960 a sand filter in it. And the sand filter is 0:43:03.960 --> 0:43:06.439 exactly what it sounds like. It's a filter that's made 0:43:06.480 --> 0:43:09.760 up of different grades of sand. You have very fine sand, 0:43:10.080 --> 0:43:12.960 then you have medium, and you have really coarse sand. 0:43:13.560 --> 0:43:16.279 And wherever the water is coming in from, it's going 0:43:16.320 --> 0:43:18.759 to hit the course sand first and then move through 0:43:18.800 --> 0:43:23.719 progressively finer grains of sand. You can have versions where 0:43:23.719 --> 0:43:27.080 the sand filter is fed through the bottom, so you're 0:43:27.120 --> 0:43:29.680 forcing water in through the bottom, it hits the coarse sand, 0:43:29.680 --> 0:43:33.520 and then the continuing force of water is pushing water 0:43:33.680 --> 0:43:35.960 further up through the filter. Or you can do it 0:43:36.040 --> 0:43:38.600 the other way, where water is coming in through the top, 0:43:38.840 --> 0:43:41.600 hits the coarse sand, and then filters down through it. 0:43:41.920 --> 0:43:46.719 Most sand filters tend to take the bottom up approach, 0:43:47.320 --> 0:43:50.799 so we would just keep forcing water in and the 0:43:50.800 --> 0:43:53.800 water would move up through these different grains of sand. 0:43:54.840 --> 0:43:58.040 So how does it work. Well, it gets super technical, 0:43:58.239 --> 0:44:02.960 so stick with me. The particulates, the particles they're in 0:44:03.000 --> 0:44:06.600 the water, get caught on the sand as they encounter 0:44:06.719 --> 0:44:09.560 spaces where water can squeeze through, but the particles can't see. 0:44:09.640 --> 0:44:13.239 I told you super technical. So yeah, the water continuously 0:44:13.320 --> 0:44:16.040 moves through areas of sand that are more and more 0:44:16.080 --> 0:44:19.080 densely packed together, and more and more of those particles 0:44:19.280 --> 0:44:23.520 are kept behind. Some water treatment plants will then pass 0:44:23.680 --> 0:44:27.399 that filtered water through a second filtration system where they'll 0:44:27.480 --> 0:44:31.080 use something like activated carbon, and the carbon particles are 0:44:31.120 --> 0:44:35.279 porous and they can capture smaller particles and bacteria and 0:44:35.320 --> 0:44:38.680 remove that from the water. So if your fridge as 0:44:38.719 --> 0:44:42.080 a water filter built into it, it's likely using activated 0:44:42.120 --> 0:44:44.960 carbon to do the trick, the carbon grabs onto the 0:44:44.960 --> 0:44:47.960 particles and the water is free to go about its business. 0:44:48.280 --> 0:44:50.960 Then the water moves on to the next phase of 0:44:51.000 --> 0:44:54.920 the treatment system, which is disinfection. This is the phase 0:44:54.960 --> 0:44:57.960 that is intended to remove any remaining bacteria to make 0:44:58.000 --> 0:45:00.960 certain that the water is safe for human consumption. There 0:45:00.960 --> 0:45:03.520 are a few different methods in order to do this. 0:45:03.640 --> 0:45:07.000 One of them is used a chlorine based compound. This 0:45:07.080 --> 0:45:09.919 is a really common approach in the United States. One 0:45:10.120 --> 0:45:13.160 is to use an ozone treatment, and then the third 0:45:13.360 --> 0:45:16.520 is to use UV light treatment, and some facilities use 0:45:16.560 --> 0:45:21.040 a combination of these. All three have different pros and 0:45:21.120 --> 0:45:26.680 cons Chlorine, for example, can continue to kill bacteria even 0:45:26.800 --> 0:45:29.680 after it's moved out of the water treatment facility because 0:45:29.680 --> 0:45:33.240 there's still some chlorine in the water. So that means 0:45:33.560 --> 0:45:37.319 that this particular type of treated water can kill bacteria 0:45:37.440 --> 0:45:40.480 that gets introduced to the system after water has left 0:45:40.480 --> 0:45:42.759 the treatment plant. So if there's any point in the 0:45:42.800 --> 0:45:46.239 system where water from the outside environment can seep in, 0:45:46.719 --> 0:45:49.480 that chlorine can help take care of any bacteria that's 0:45:49.480 --> 0:45:54.279 in that water. The other two versions of of disinfection 0:45:54.480 --> 0:45:57.440 don't allow for treatment of water once it's left the 0:45:57.440 --> 0:46:00.880 treatment plant, but they have their own os and cons. 0:46:01.200 --> 0:46:04.280 Now at this stage the water should be safe to drink, 0:46:04.280 --> 0:46:07.239 assuming everything at the water plant is working properly, so 0:46:07.320 --> 0:46:10.239 you've now reached drinkable water. Once it's gone through all 0:46:10.280 --> 0:46:13.760 these phases, then it gets pumped into the city's water system, 0:46:14.000 --> 0:46:16.000 which is a network of pipes that feed out to 0:46:16.080 --> 0:46:18.279 the various homes and buildings in the city, with other 0:46:18.320 --> 0:46:20.399 pumps along the way to keep the water pressure going. 0:46:20.880 --> 0:46:24.000 And the water pressure leaves the planted around a pressure 0:46:24.000 --> 0:46:26.440 of for d P s I, and that is to 0:46:26.600 --> 0:46:29.440 make sure of a few things. One that the water 0:46:29.560 --> 0:46:31.360 has enough pressure so it can be pumped up to 0:46:31.480 --> 0:46:34.880 areas of higher elevation. And two there has to be 0:46:35.000 --> 0:46:37.520 a positive water pressure in the pipes. In other words, 0:46:37.680 --> 0:46:39.360 the water pressure in the pipes has to be strong 0:46:39.480 --> 0:46:42.040 enough so that the water is pressing outward on the 0:46:42.080 --> 0:46:45.680 pipes at all times, because that prevents any other water 0:46:45.880 --> 0:46:50.400 from outside from seeping into the pipes. If there are 0:46:50.400 --> 0:46:54.440 any gaps or cracks along the way, the internal water 0:46:54.480 --> 0:46:58.120 pressure is strong enough to push that water out so 0:46:58.200 --> 0:47:01.360 it's not gonna it's not able to get in, and 0:47:02.080 --> 0:47:04.840 that's important because if water could get in while that 0:47:04.880 --> 0:47:07.719 water would be untreated, and you would have all the 0:47:07.800 --> 0:47:11.960 dangers that are associated with contaminated water sources all over again. 0:47:12.040 --> 0:47:14.440 It would have been as if the whole process you 0:47:14.520 --> 0:47:17.960 just went through at the treatment facility didn't matter. So 0:47:18.000 --> 0:47:21.719 if there's an indication that's somewhere along the water system 0:47:21.760 --> 0:47:24.560 from the treatment plant to the homes or buildings where 0:47:24.560 --> 0:47:28.160 the water is being delivered, that pressure has dropped somewhere 0:47:28.200 --> 0:47:31.000 along that pathway, that's when you tend to get boil 0:47:31.080 --> 0:47:35.080 water advisories. The concern is that if water pressure is 0:47:35.160 --> 0:47:38.680 low enough, then external water might have entered the pipe 0:47:38.719 --> 0:47:41.680 system and so it could be untreated water and it 0:47:41.680 --> 0:47:44.239 would be unsafe to drink. That's why you're told to 0:47:44.280 --> 0:47:47.560 boil your water. It's really to kill off any potential pathogens. Now, 0:47:47.600 --> 0:47:50.440 boiling water won't remove everything, so you might end up 0:47:50.480 --> 0:47:53.520 with water that has higher concentrations of stuff like iron. 0:47:53.600 --> 0:47:58.040 But the primary concern, the first line of concern, is 0:47:58.120 --> 0:48:02.640 about potentially deadly bacteria like E. Coli. One of the 0:48:02.640 --> 0:48:06.880 most common municipal water system components is the water tower. 0:48:07.320 --> 0:48:10.200 Now you've likely seen lots of these. They are tall 0:48:10.320 --> 0:48:13.880 containers giant, giant containers that can hold a lot of water. 0:48:14.239 --> 0:48:17.239 So like your typical swimming pool holds something around the 0:48:17.280 --> 0:48:20.360 line of twenty tho gallons of water, the typical water 0:48:20.440 --> 0:48:24.359 tower can hold a million gallons. But usually a water 0:48:24.400 --> 0:48:28.120 tower is designed so it holds about a day's worth 0:48:28.239 --> 0:48:33.120 of water supply for the area that water tower services. 0:48:33.160 --> 0:48:36.000 So these water towers are really tall. They often are 0:48:36.040 --> 0:48:39.000 put in places of higher elevation because they depend on 0:48:39.080 --> 0:48:42.760 gravity to do a lot of work. Each additional foot 0:48:42.840 --> 0:48:47.080 of height that you have a container of water at 0:48:47.440 --> 0:48:50.640 increases the water pressure by point four three pounds per 0:48:50.680 --> 0:48:54.279 square inch. So the taller the tower, the higher the 0:48:54.280 --> 0:48:57.759 water pressure. Lifting a volume of water to a high 0:48:57.760 --> 0:49:00.680 point builds up a lot of potential in gy and 0:49:00.760 --> 0:49:03.480 releasing the water and letting it fall converts that potential 0:49:03.560 --> 0:49:06.160 energy into kinetic energy. But in a plumbing system in 0:49:06.160 --> 0:49:08.440 which you've got water filling up the system of pipes, 0:49:08.760 --> 0:49:12.120 the potential energy converts over into water pressure. So let's 0:49:12.120 --> 0:49:14.759 imagine you've got a water system in place for an 0:49:14.880 --> 0:49:18.120 unoccupied city. No one lives in the city, but you've 0:49:18.120 --> 0:49:20.200 got the water system set up, You've got the water 0:49:20.280 --> 0:49:22.759 tower filled up all the taps in the city are 0:49:22.800 --> 0:49:25.960 turned off. It's a sealed system. Right now, the weight 0:49:26.080 --> 0:49:28.080 of the water in the water tower is creating some 0:49:28.120 --> 0:49:31.440 water pressure throughout the system even if the pumps aren't on. 0:49:31.640 --> 0:49:34.160 So you open up a tap that creates an escape 0:49:34.160 --> 0:49:36.120 for the water and the water will come out of 0:49:36.120 --> 0:49:38.480 the pipe. The water towers are really there to act 0:49:38.520 --> 0:49:40.719 in a way kind of similar to the way a 0:49:40.800 --> 0:49:44.080 pressure tank works. With a house that has a well 0:49:44.560 --> 0:49:48.040 as its source of water, the water tower helps reduce 0:49:48.160 --> 0:49:51.120 the workload that the pumps in the system have to do. 0:49:51.560 --> 0:49:55.839 If we didn't have water towers in times where people 0:49:55.880 --> 0:49:58.120 were using a lot of water where demand is really high, 0:49:58.120 --> 0:50:00.680 then pumps would need to power up more. They would 0:50:00.680 --> 0:50:04.200 have to work harder to deliver water to meet that 0:50:04.320 --> 0:50:08.000 demand and to keep the system working. That requires more energy. 0:50:08.080 --> 0:50:10.640 It also results in more wear and tear on the pumps. 0:50:10.640 --> 0:50:14.400 But by storing water and water tanks and water towers, 0:50:15.040 --> 0:50:18.040 then we can use that to help supplement the water 0:50:18.120 --> 0:50:20.400 that's being supplied by pumps. We can keep running the 0:50:20.400 --> 0:50:24.200 pumps at a consistent level, which reduces wear and tear 0:50:24.280 --> 0:50:28.000 and is more energy efficient, and then we supplement that 0:50:28.080 --> 0:50:29.960 with the water from the water towers, and at night, 0:50:30.040 --> 0:50:33.800 when water demand is usually pretty low, then special pumps 0:50:33.800 --> 0:50:36.279 can pump water back up into the water tanks to 0:50:36.400 --> 0:50:39.560 refill them so that we again have a full day 0:50:39.600 --> 0:50:42.560 supply raid to go. At the beginning of this episode, 0:50:42.719 --> 0:50:46.640 I mentioned Flint, Michigan, and that the crisis that went 0:50:46.680 --> 0:50:50.200 on in the city's water supply. So what happened. Well 0:50:50.200 --> 0:50:53.160 back in two thousand eleven, Flint, Michigan was in a 0:50:53.320 --> 0:50:57.560 really tough spot financially. The city had been largely built 0:50:57.600 --> 0:51:00.480 around the automotive industry in the United States. In the 0:51:00.520 --> 0:51:03.759 nineteen sixties, the population of the city was around two 0:51:03.800 --> 0:51:07.080 hundred thousand people, but the automotive industry in the United 0:51:07.120 --> 0:51:11.480 States went through a total tumultuous time. Foreign car companies 0:51:11.719 --> 0:51:15.160 were able to really compete fiercely in the market in 0:51:15.200 --> 0:51:18.680 the United States, and American companies ended up having some 0:51:19.440 --> 0:51:22.520 massive problems as a result, and a lot of that 0:51:22.560 --> 0:51:26.040 meant that businesses started to move out of certain areas 0:51:26.160 --> 0:51:29.560 like Flint. So by two thousand eleven, with the automotive 0:51:29.560 --> 0:51:34.120 industry largely absent from the city, Flint's population was less 0:51:34.120 --> 0:51:37.560 than half of what it had been in the nineteen sixties. Now, 0:51:37.600 --> 0:51:40.640 that also meant that the city was taking in less 0:51:40.680 --> 0:51:43.520 money in the form of taxes. Not only was the 0:51:43.560 --> 0:51:46.560 local economy suffering because of the failure of the automotive 0:51:46.560 --> 0:51:49.560 industry there, the city's coffers were empty, and the city 0:51:49.640 --> 0:51:52.839 was actually in debt. In an effort to deal with 0:51:52.880 --> 0:51:56.879 this financial emergency, the city appointed managers who could make 0:51:57.000 --> 0:52:01.279 drastic cost cutting measures without going through the typical political processes, 0:52:01.920 --> 0:52:05.360 so they didn't have to seek after approvals, which sped 0:52:05.440 --> 0:52:08.600 things up considerably. The idea being that it was important 0:52:08.640 --> 0:52:12.799 to be expedient here. So one of the expenses that 0:52:12.880 --> 0:52:17.440 they identified was the water supply. Flint had been buying 0:52:17.880 --> 0:52:22.440 water service from Detroit. Detroit was processing the water and 0:52:22.440 --> 0:52:25.920 then sending it on to Flint, Michigan. So instead Flint wood, 0:52:25.960 --> 0:52:28.800 for at least a short time, starting in two thousand fourteen, 0:52:29.440 --> 0:52:33.160 draw water from the Flint River while building out its 0:52:33.200 --> 0:52:36.399 own regional water system with the goal of pulling water 0:52:36.480 --> 0:52:39.200 from Lake Huron, which was the same source as what 0:52:39.280 --> 0:52:42.280 Detroit was using. But the water coming out the Flint 0:52:42.360 --> 0:52:47.120 River was really contaminated, and the treatment system that Flint 0:52:47.160 --> 0:52:50.759 was using was not capable of treating the water properly. 0:52:51.080 --> 0:52:54.520 And here's where we got a tragic dilemma, because people 0:52:54.560 --> 0:52:57.160 need water, but the water that was coming out of 0:52:57.160 --> 0:53:01.120 the Flints system was unsafe to drink, and that unsafe 0:53:01.120 --> 0:53:05.120 water got pumped into the city's system and to people's homes, 0:53:05.120 --> 0:53:08.239 and some regions got worse water than others, and it 0:53:08.280 --> 0:53:11.360 was all pretty nasty stuff. You can actually watch videos 0:53:11.360 --> 0:53:14.720 of people turning on faucets filling up a clear glass, 0:53:14.760 --> 0:53:17.759 and you can see that the water is discolored. But 0:53:17.840 --> 0:53:22.799 apart from looking and reportedly smelling bad, it carried with 0:53:22.880 --> 0:53:28.640 it lots of contaminants, including dissolved lead. Lead is incredibly toxic. 0:53:28.719 --> 0:53:31.960 There is no level of lead that is considered safe, 0:53:32.400 --> 0:53:36.279 and consuming lead can lead to lifelong health problems. For 0:53:36.440 --> 0:53:40.480 a year, the city denied that there were elevated levels 0:53:40.520 --> 0:53:44.800 of lead in city water, claiming that any specific cases 0:53:44.840 --> 0:53:49.520 where people detected higher levels of lead, we're just restricted 0:53:49.560 --> 0:53:53.239 to the plumbing of those specific buildings or houses, saying, oh, 0:53:53.239 --> 0:53:55.360 it's not a it's not a systemic problem. It's a 0:53:55.360 --> 0:53:58.839 problem with your plumbing. And it took an outside investigation 0:53:58.920 --> 0:54:02.040 that proved otherwise. It said, no, this is a city 0:54:02.160 --> 0:54:05.120 level problem, and it means that people have been relying 0:54:05.160 --> 0:54:09.120 on a water system that was contaminated for a full year. Now, 0:54:09.120 --> 0:54:13.160 in two thousand fifteen, under immense pressure, Flint switched back 0:54:13.239 --> 0:54:17.239 to using water from Detroit, but by then a lot 0:54:17.280 --> 0:54:20.480 of damage had already been done. Now you'll occasionally see 0:54:20.520 --> 0:54:23.560 the message of Flint, Michigan still doesn't have safe drinking water, 0:54:23.640 --> 0:54:27.240 but that's actually not true. The water in Flint, Michigan, 0:54:27.280 --> 0:54:30.160 is now as safe or safer than other cities in 0:54:30.200 --> 0:54:33.560 the United States. However, the amount of damage that was 0:54:33.719 --> 0:54:37.920 done during the switch to the Flint River remains a problem, 0:54:37.960 --> 0:54:40.440 and for many residents it could be a problem that 0:54:40.520 --> 0:54:42.440 they have to manage for the rest of their lives. 0:54:42.800 --> 0:54:48.120 So that explains the challenges associated with delivering water to 0:54:48.239 --> 0:54:52.760 people now in our civilized age, is still a massive 0:54:52.960 --> 0:54:55.799 undertaking and obviously if something goes wrong, it could have 0:54:56.080 --> 0:54:59.200 dire consequences. And it reminds us that we have to 0:54:59.200 --> 0:55:01.360 be very careful with our water supplies. Even with the 0:55:01.360 --> 0:55:04.080 water treatment systems that we have, we need to be careful. 0:55:04.640 --> 0:55:08.040 It is easy to contaminate a water supply, whether that 0:55:08.280 --> 0:55:12.359 is a river or a lake or even groundwater. If 0:55:12.400 --> 0:55:17.920 you have poor wastewater treatment plans, then that wastewater can 0:55:17.920 --> 0:55:21.400 seep into the ground and then you've got very dangerous 0:55:21.400 --> 0:55:25.239 bacteria and other contaminants in the water system that could 0:55:25.239 --> 0:55:29.480 then be consumed later on. And that's why this is 0:55:29.520 --> 0:55:33.680 so important, and the technology involved is pretty interesting stuff. 0:55:33.719 --> 0:55:37.120 I highly recommend watching videos. I know that trying to 0:55:37.280 --> 0:55:40.200 visualize something like a centrifugal pump as a little tricky, 0:55:40.440 --> 0:55:42.959 but there's some great videos on YouTube that really show 0:55:43.000 --> 0:55:45.600 you how it works in case you want to get 0:55:45.600 --> 0:55:48.719 a visual on it. These things are really super cool, 0:55:48.760 --> 0:55:52.720 and again, the harnessing of physics is something I always 0:55:52.760 --> 0:55:56.319 find really fascinating. If you guys have any suggestions for 0:55:56.440 --> 0:55:59.480 future topics of tech stuff, whether it's a technology or 0:55:59.520 --> 0:56:02.560 a trend, into or a company or whatever something related 0:56:02.600 --> 0:56:05.920 to tech, send me a message and tell me about it. 0:56:06.200 --> 0:56:08.440 You can send it on Twitter. The handle for the 0:56:08.480 --> 0:56:11.879 show is tech Stuff H s W and I'll talk 0:56:11.880 --> 0:56:20.080 to you again really soon. Text Stuff is an I 0:56:20.200 --> 0:56:23.680 Heart Radio production. For more podcasts from I Heart Radio, 0:56:24.000 --> 0:56:27.200 visit the I Heart Radio app, Apple Podcasts, or wherever 0:56:27.280 --> 0:56:28.800 you listen to your favorite shows.