Ear on Chicago; Water Filtration

You've just heard the sound of a centrifugal water pump being started up at the South District filtration plant. And this is Hugh Hill speaking to you from that filtration plant, where today, Iran Chicago is doing the story of how Chicago gets its filtered water supply. This South District filtration plant is located at 3 ,300 East Chiltingham Place. Now, for those people that are not acquainted with where Chiltingham Place is, the location of this filtration plant is in the general area of 79th Street and Lake Michigan. We're going to talk to a number of people today about the filtration plant, but our guide on the program is the engineer of water, Mr. John R. Bayless. Mr. Bayless, as I understand it now, you have eight of these pumps taking water that has been taken in from the crib. We're standing at pump number seven. Number seven wasn't working just a few minutes ago, and they started it up

all about a minute and a half before we went on the air. Now, I can count down from here and see that you do have eight pumps working, or at least eight pumps, half of which you're working. You only keep half working at a time. I keep whatever is required to pump the amount of water. It may be from one half to about three fours of the pumps. Now, these pumps are bringing water in at a very rapid rate from a large basin, which is located just behind this wall here, which is painted green. Is that right? That's right. Now, tell me the dimensions of that basin back there. First of all, about how much water does it hold? About two million gallons, as divided into two basins each is about 190 feet long, and about 60 feet wide. How deep? 25 feet deep. Now, that water is raw lake water, which is brought in from the crib. Is that right? That's right. Why do you have a crib out in

the lake about three miles? Why can't you take the water directly from the lake? We do take the water at times, some of the water directly from the lake, but the water out at the crib is a little better quality than the water along the shoreline. How deep is that crib? How far does it go down to get the water? 25 to 30 feet. It's opening to the end of the crib. We have in front of us here a diagram of the water of how the water gets from the crib back here to the filtration plant and then into the apartment buildings around the city of Chicago. Now, I better let you describe it, Mr. Betas, because I may say something that might be wrong here. The water enters the end side of the crib through porch near the bottom of the lake, then it goes upward and overshows that extend down about 150 feet

below lake level and to a solid rock and from there, over to the filtration plant. In other words, the water is brought from the crib through some sort of a tunnel. That's right. A tunnel that's blasted through a solid rock and lined with concrete. How big is that tunnel? The new portion is 16 feet in diameter. The old portion is 14 feet. So now the water is brought in through the tunnel and is stored in a basin, which you call the raw water basin, is that right? They call the intake basin. That's one we're talking about just behind us here. That's right. Well now, one final thing, we mentioned that there are eight pumps. How much does each pump pump during a given period of time? Four pumps, well, pump 120 million gallons a day. That is for 24 hours. Now, we're listening

to four pumps working right now. Four other pumps will pump 65 million gallons in 24 hours. Do you ever have them all working at the same time? No. We don't. We wish to have at least one pump idle in case there would be an accident to a pump where it would still have sufficient capacity with our largest size pump in out of service. All right. Now we have the water brought in by the crib and from the crib into their catch basin here just behind this huge wall. And now the pump is pumping the water from the basin over into another part of the building. Now, that's the next step that we want to watch. What is it? First, they've got through what it calls the raw water conduits. From there, it goes to the chemical application channels where the chemicals used in coagulating the water are applied. So we're going to see the chemicals added next. Is that correct? I

tried. All right, let's move on. That's the sound of some of the machinery that they have here to mix the chemicals with the water as it comes in from Lake Michigan. We're going to talk now to Mr. James Vaughn. I'm going to ask him to give us his title. It's a little bit long title, so I may forget it. I am Assistant Chief Water Chemical Engineer of the South District Filtration Plan. So I say it's a little bit long. Well, Mr. Vaughn, first of all, let me describe this room and what is going on in here. There's a large series, a long series of hoppers containing the chemicals. A moment ago, as we were traveling from one building to the other, coming over here to where the chemicals are added, we passed a railroad spur where they have railroad cars filled with the

chemicals that are delivered here to the filtration plant. Chemicals are then passed into the pipes, up into the hoppers, and are dropped down through the hoppers into this machinery. In front of each one of these hoppers is a scale. What's the scale for? The way they chemical, I suppose. The hopper is part of this scale, and the loss of weight each hour is the measure of the exact amount fed to the particular point of application during the past hour. I didn't count the number of hoppers here, so I'm not going to take a while, guess at it, but it looks like a large number. Do you know how many? They are 36 altogether. 36 of them. Now, here's a group down here, here's another group together here, and then another group, and some more way down at the far end of the building. This building is a very long one, by the way. I'd say it's a good 300 yards long, maybe not that long, but it looks that way from here, about maybe 250 yards, but it's a long building. And you have these machinery grouped into segments here. Why do you do that? The plant

consists of three mixing and settling basins, and each mixing and settling basins has its own group of chemical feeders. We're going to see that mixing and settling basins a little later, aren't we? Yes. All right, now, precisely what is the chemical being added, for example, in this spot right here? This particular feeder applies ammonium sulfate to the water. What other chemicals are added to the water here? We add as coagulating agents, aluminum sulfate, and iron sulfate. And we add as sterilizing agent chlorine. We add for the purpose of removing objectionable tastes and odors from the water. We add activated carbon, which is a specially treated form of pulverized charcoal. So when we get our drinking water at home, we have a lot of chemicals in it, don't we? Most of the chemicals that are added are removed in the settling infiltration process. The only thing that remains, as the water leaves the plant that we have added, is enough chlorine to make the water safe to drink, and the required amount of

fluorine for the prevention of dental caries. That's just a recent addition to fluorine, isn't it? That began at this plant, May the 1st, 1956. Well, I hope we're all getting better teeth for it, Mr. Bond. Let's you and I walk down the line here just a little ways. There's some other machinery down here, that I wanted to take a look at. Here's a sign up here, danger corrosive liquid. What's that? Well, this happens to be the room wherein the hydrofluosolic acid is applied to the water. This contains the fluorine, and it is an acid, and therefore it is corrosive. All right, now here is a button or something here, a fluoride metering pump switch. By the way, we're talking about fluorine, and I always thought it was fluoride. Fluorine is the element. The salts of fluorine are called fluorides. Any number of them, sodium fluoride, calcium fluoride, and so forth. Is this where the fluoride is added in this room? Yes, this small pump you

see with three... Let's go take a look at it. We'll take a closer look at it. We've walked into a different room now. You may be able to tell it by the different sounds. A more hollow ring to this room. Listen to the machinery just for a moment. Now I want you to hear the flow of some water through a pipe down here, and then we'll tell you what's going on. I think you could probably hear that. Mr. Vaughn, what's going on with that water flowing around down there? As I said before, the hydrofluous elicic acid is a very corrosive liquid, and we have this sump built around the pump with water flowing through a shore so that if any leaks occur, which can't happen in a time, the water will flex the acid down through the drain, into the basin, and will not be lost to use. Now how many pumps do you have in here? For example, this one pump has three heads, one for each of the

three mixing and settling basins. I see. All right. Now we have the chemicals added. Let's get back over here to Mr. Bayless. Mr. Bayless wants that we have the... By the way, thank you very much, Mr. Vaughn. We may get to back to you a little bit later. Mr. Bayless, now that we have the chemicals added to the water, what is the next step in the filtration? Formation of the coagulation. That's done by running through basins with agitation. It's not very violent. It's a sole motion of the paddle that brings together the bacteria and particles of mud and to a masses of particles that can be easily filtered on the felders. That's your settling basin. That's a mixing basin. From the mixing basin, the water goes to the settling basin where about 75 % of the impurities settle out and then to the

felders. All right. Let's move on. I think you may be able to hear there the slight trickle of water. There's current here in a channel that is moving the water through the channels and being mixed with the chemicals that we were talking about just a moment ago. There may be a rather hollow sound to this room, I think, perhaps there will be. We're standing in a large concrete channel and this is really, according to Mr. Ballus, the only place where we can actually get a real good look at Lake Michigan water after it has been mixed with the chemicals. Now, actually, the mixing process is taking place all around. Is it,

Mr. Ballus? Yes. This is a second or two mixing conduits. It goes into the first conduit and most of the chemicals are applied in the first conduit and it goes into the second conduit that deals with a more thorough mix to be assured that each gallon of water has its proportion of chemicals. Well, now, Mr. Ballus, since the next stop we're going to make is over at the filter basin and we're going to pass by the settling basin and the mixing basin. I would like for you to tell us a little bit more specifically how those two operations work because we want to jump over to the filtration actually, the filter basin because there isn't really much to see as you pointed out a little while ago. There really isn't much to see in the mixing basin or in the settling basin because it all takes place inside of some huge walls. So we will be able to actually

see it. So I'd like for you to tell us about it while we're standing here. What we turn the slow mixers, which is a mixers that form the coagulation of the chemicals, has a shaft running through each channel with paddles on the shaft that keep the water as it flows through and gentle motion. It requires from 15 to 30 minutes to form a good coagulation so that all of the bacteria, microorganisms and small particles of mud are entrapped into the coagulated particles, which is a mass of particles that is large enough to be filtered with the filters. Since these masses of particles are a considerable size, they'll settle rapidly in settling basins. Therefore the filters

can be relieved of a great deal of the amount of material to be filtered by letting the water go through these settling basins where the sediment is growing out mainly once every day. Twice a year the basin is drained and any remaining sediment in the basin is flushed with fire hose. Well now once this water has settled down through the basin, what is left in the basin? I know that clear water is left as far as the water is concerned but what do you find in the basin besides mud? There's always a few small fish, any fish that can go through the screens out at the intake or at the crib or can come on into the

plant. We quite often see live fish in the water. It has a large amount of microscopic organisms that vary all the way from organisms that you can just see with the eye to organisms that are quite small and require microscope to observe. How do you get rid of the mud, Mr. Bayless? That from the settling basins are stated as removed once daily with scrapers in the basin and that scrapers may ask are they operated manually or are they operated by machinery? By machinery there are boards that are pulled across the floor of the basin carrying the sediment to places where pumps pick it up and pump

it 3 ,600 feet out into the lake. What's that pump? Imagine that water or sediment or whatever you call it out of the lake is a pretty much of a mess out there, isn't it? It is. It's quite turbid, of course, because it's taking a sediment that has come out of the water. In other words, all of the sediment that is taken out of the water in the filtration process is returned to the lake. What, how much mud is there each day? It varies from 10 to 50 tons a day. All right, Mr. Bayless, I think it's time now to move on over to the filter process and we'll take a look at that. That fast rush of water that you

hear is from the filter basin from one of a very large number of filter basins. We're speaking now from a ledge which looks over basin number 74 and we're going to talk now for a moment to Oscar Gullens who is going to tell us about the filter basins. Oscar, well, first of all, may I have your title? Chief Water Chemical Engineer. Oscar, first of all, may I ask you how much water does this one basin here hold? This one filter holds about 70 ,000 gallons of water and filters approximately anything from 4 to 8 million gallons of water a day. The filter is being cleaned now. Actually, the water that is filtered down through the filters, it's a large layer of sand and gravel will tell you about that in a minute. And after the water filters down through, of course, it leaves a deposit of mud and sediment and they have to clean the filter every once in a while. That's the process through

which they are going right now. Water is being, well, let me have Oscar describe it, what has actually happened? We have set off the flow of water through the filter and we are backflushing a heavier flow of water back through the sand to flush the dirt and mud out of the sand and into a series of washed water truss which carry this water and sediment away. We do not remove any of the sand, the sand stays behind is merely put in floatation and when the sand is cleaned, the water comes through clear from under the filter. We're standing at basin number 74 and just to the left of us, I guess is basin number 73 and the one on the right is basin number 75. There is water that looks as if it's standing in there, actually it's moving down through the filter. At a moment ago, we were standing here and the water was at the same level, it looks very clear. But as it filters down

through, it leaves a large deposit. Now, once the water is out of here, Oscar, what will happen? It'll just, the clear water will be brought back in. That's right. And then again, the filtering process will take over. The filtering process then continues. Now, actually, how does the filter work? It filters down through sand and gravel. Each drop of water going through this sand layer must pass through approximately 3000 little cracks and openings between the sand grains. And as this water trickles through anything in suspension, even bacteria gradually become lodged in these little cracks so that by the time the water reaches the bottom of the sand layer, it is perfectly clear and filtered clean. The expansiveness of this room, Oscar, is really astounding. We're only talking about one basin. How many basins are there? We have 80 in all. And how much does the water, each basin hold again? Approximately 40 ,000 gallons. So that means that you have 80 of them and 40 ,000 gallons, that would be how much water total? About

three and a half million gallons on the filters. And that goes through continuously, yes, sir. All right. Thank you very much, Oscar, for telling us about the filters. Mr. Balus, we want to get back to you to close our program. How do you check the water to make sure that it is pure? The water is tested from the raw lake water through the different processes and the plant. And then of the final water that is delivered to the city. Of the water that is delivered to the city, the samples are collected four hours apart and tested for bacteria and coliform organisms. This is the largest filtration plant in the world. Is it not, Mr. Balus? That's right. They're building another one on the north side of Chicago. That'll be a little more than twice the size of this one. Well, Mr. Balus, we want to thank you very much for showing us through the filtration plant. We've certainly enjoyed the trip and

it's been a very interesting and educational trip for us and I hope for the listeners. Thank you, sir. Quite pleasure to show you through. And that's the story of the South filtration plant of the city of Chicago. Listen to that water go. This is Hugh Hill speaking.