Polyurea For Wastewater Coating Applications



Today I am going to discuss the uses of pure polyurea in wastewater coating applications, including where and why pure polyurea can be used with confidence.

Some general facts:
Many of you are probably well aware that our water usage is not only increasing but our water availability is decreasing. Many of the water treatment plants that are available today in use have been in service for well over 30 years and that infrastructure is beginning to deteriorate. Choices of building new facilities or retrofitting old facilities are individual water authority requirements. But we do know that in 2010, that was roughly 91 billion dollars spent to maintain our water systems. By 2022 they're expecting that to increase to one hundred and fifty dollars billion. So you can see there's quite an opportunity for Polyurea in these new builds or retrofits.

So what does that mean for pure polyurea? 
It's an opportunity for this technology to extend the life of existing water treatment structures. It has the ability to delay or fight or control common corrosion issues that we'll go into in this presentation and needs to assist the water engineers in cost savings with long-term results.


Quick review
What do we know about pure polyurea? 
It's a two-component spray elastomer, the reaction of an isocyanate and an amine resin. It is zero VLCC 100 percent solid and is 100 percent reactive. The speed is quite quick in tack-free and cure, we can have systems that will react to tack-free in a matter of seconds and after two minutes as very low pro-rating, which is going to have excellent resistance to hydrogen sulfide. 

And as we'll show you, it's used as a coating liner from the very front of the system to the very end of the system of wastewater treatment plants.

Polyurea is going to can be used on properly prepared concrete and steel surfaces. And as an industry, we refer back to HSSVC as standards for surface prep. We can also use polyurea in liners and over Geotech stuff for "containment berm" water basins. 

Let's first look at what is going to be or what could be in the water as it enters the treatment plant. We know that over the years, the chemical compositions of what can go into that water have changed dramatically. We can get a chemical attack in many forms. We're going to talk about the composition of the waste stream. Biogenic corrosion, sulfur-oxidizing bacteria, we're talking about inorganic acids, a combination of concrete. The vapor phase, sulfate attack, abrasion, chloride inducing deterioration and weathering. So let's look at what the streams are that's going into the waste water treatment plant.

First, let's just look at domestic, and you can see by these photos, you can picture in your mind, you can think of what you just put down the sink of the toilet last week. Anything from the toilet, disinfectants, detergents, lawn fertilizers medications are starting to play a big role in the chemical makeup of the street. We continue even with the best efforts of the industrial community to have contamination, depending on the plant process, every plant's going to have an affluent.

There can be disasters that can be spills. These things can get into our water system. And of course, we've got your normal infiltration, just the run of the mill stuff, fertilizers, pesticides and any kind of debris can get into the water stream. We have weather this this isn't new, this is this is standard, it's you get weather in either from the salt atmosphere along the coast, moisture freeze thaw.

A brazen. As well as just age, the plants are aging as we continue on. You also have solids, you have solids in the water. You have solids that are processed in the facility's. And you have debris from the influence, the grip chambers and, of course, the environmental effects.

OK, let's look now more at the manufacturer that we've talked about, two types of gases. The first is an organic gas, and these are going to lower the PH of the strain, which will begin to attack the concrete.

The acid is going to react with the calcium hydroxide in the concrete and you'll have a loss of structural integrity. You'll see a lot of this in squalene applications as it's going to come from your house, from an industrial and any other byproducts, such as citric acid or south. Inorganic acid's will come in from fertilizers and pesticides, pulls supplies flowing for supplies, cleaning solutions. These will be in the form of, say, for example, hydraulic or nitric.

You can see by this photo the aggressive attack on the concrete due to these assets present in the water. Then we get into biogenic corrosion. In any of these processes, you're going to generate and have frozen sulfate ions. These are going to be on the surface of the tank or pipe and are anaerobic. They begin to consume oxygen from the sulfate ions, resulting in a byproduct. That can then react to form hydrogen sulfide.

Which then continues to have hydrogen sulfide gas. In closed tanks these react moisture to lower the age, and it causes erosion of the concrete and steel surfaces, not to mention the odor. Sulfur oxidizing bacteria or SOB's are going to colonize on the surface of this tank if moisture and oxygen is present. The hydrogen sulfide is going to be oxidized to form sulfuric acid, which is going to be very aggressive with the calcium hydroxide. In the concrete, it is going to form calcium sulfate gypsum.

This is going to eventually be washed away and you exposed the rock and the inner materials. Further weakening the concrete structure. The vapor phase is where. SL4 concentrates and starts to penetrate the concrete and reacts with the components of the concrete. Typically, this is just above the waterline, which is probably the strongest. And is going to expand the beyong its tested strength and you'll get significant gains following. You'll have combination of concrete, which is going to occur in all the exposed concrete, calcium hydroxide and calcium dioxide is going to react to form calcium carbonate.

It's going to cause shrinkage of the concrete, again, starting the deterioration process of the walls.

The benefits of "polyurea" in these systems. The first area I'd like to talk about is the fact that we all know one thing about concrete, and that is it will crack.

I just gave you several reasons why that will occur. Because Polyurea has a high level of flexibility, systems can range from 200 to 500 percent even larger. Then the application of Polyurea over this concrete once the crack continues to develop we can maintain the coding continuity by ASTM standards, up to one eighth inch crack down to minus 20 degrees Fahrenheit. Typical earlier coatings that were applied in these systems were thin film with lower elongation, 5-10 percent elongation.

So when a crack does occur in the concrete. That is going to be married by the coating. And you will see the cracks in the coating.  Elastomeric coating for concrete will bridge those cracks and is going to maintain the integrity of the coating. This is an example or demonstration of the flexibility bridging of polyurea. What we did was we took a concrete block paving stone and corrected. Within primed with a poxy primer and then put a polyurea on top of that.

We then put it in tents, Telmo and slowly began to separate the two pieces of baby and still. As you can see on the left. There's a one inch span. That we. Slowly developed. And you can see that the coating is still intact. In fact, there's still concrete on the side of that coating in the gap. That was done 20 times. Back and forth and on the right side, you can see that the coating remains intact.

There is not 100 percent Elastica last memory. As you can see by that little bump in the polyurea. But the important thing is that whatever this. Picture, this is a tank was containing, even though that significant crack develop. You will still have waterproofing, no leaks because of the choice of "polyeurea" on this example. Another thing that another aspect of Polyurea that makes this very beneficial, especially where you have. Concrete and steel meeting. Is the coefficient of linear thermal expansion.

This is the degree of expansion divided by the change in temperature. And it generally is going to vary. With temperature and the substrate as well as the code. So you can imagine that if these steel substrate, concrete substrate and the coating all should probably have a very close alignment in value. To prevent cracking of the code. And you can see by this chart. That polyurea typical polyurea is have a value in the range of two to six. Still will have a value of six to seven.

And concrete, five to six, so you can see that those three components. All match very closely in values. Now, if you drop on down and look at the next four. Particularly, say, in EPOXI or Urethane. These values are factors larger than. The "polyeurea", the steel and concrete. So when you have. Temperature changes, especially in the north, and you have this coefficient of Libya, thermal expansion occurring in the steel, the concrete and the coating, you can see the polyurea is an excellent choice to closely aligned with the substrate.

Now. Let's get into specifically where Ken Polyurea "polyeurea" be used in the water treatment plants. This is a general and there are so many types and varieties and variations of wastewater treatment plants, but this is a general one excuse me that. Is also very simple for me to look at, and that is you see on the left, on the upper left, the raw sewage is coming into the treatment process. You have your grip change. And then you start into your primary clarifier.

Operation. Moving towards the right secondary clarifier. Then you'll have your your water. Disinfection section. Which is then used in golf courses, it can be used in portable water, it can go back into our environment. Moving back to the center, you'll see that then the sludge is removed. And it's concentrated and it can be put into either drying ponds or landfill. Where the methane gas can be generated using to generate electricity. So the next several slides we're going to go through is going to go to break the sections out and we'll show you where Polyurea can be used.

Just recently, August 1st of this year, the SBC introduced a new Coneys specification number forty four, which is called liquid appli, organic polyurea coatings and lines for concrete structures in municipal wastewater facilities, performance based. What this is, all right, what this does is it sets out a scope for the Tank coating specification and breaks this water treatment system down into the following items, the collection systems very beginning. Preliminary treatment centers. The primary and secondary treatment centers.

Any advanced treatment? Areas that may or may not be present, the solids handling and then the storage. So the first thing in the in the in the process are going to be your collection systems. These include your mantels in English stations, pump stations, tunnels and interceptors. This is going to take the macro water from the environment. And start to directed towards the wastewater plant. If you've been out in the storm lately that I'm straight, you look at the stuff going down the drain, you've got coke cans, tree limbs, leaves, all sorts of debris as well as the contaminated water.

And so these collection systems have to be able to withstand not only the materials, but the abrasion potential. Within those systems. We moved into the plant and we're in a preliminary treatment system area, on the left is the first line of defense, if you will, where we're the screening instructions. These are going to take out any of the materials that the plant cannot treat. You're going to be in chambers where you'll have Satterley. And headworks. On the right, so there can be some abrasions, there could be some.

The normal chemicals and composition of the water at this point, and this is a fairly aggressive area of the plant. Then you move into the secondary treatment systems here, you'll have your operation bases and. Have secondary clarifies that this is way very often you're going to see the. A buddy of steel and concrete from the scammer's, the mixer's, etc. In these you you will also encounter the sulfur oxidizing bacteria, the two concentrations and the abrasions distance of the settling solids.

Clearly, in the solids handling areas, you're getting a lot denser material. They used to be very aggressive on the sides of tanks and the equipment. The digesters and dewatering structures. Finally going to get into the story, we'll have "secondary oil containment". You may have of holding ponds or just bottled water storage and clearly these need to be maintained and you do not want to lose that valuable water at this point. Polyurea is used not only in the physical side concrete storage tanks, but also in your houses, as if you will, +secondary +containment are lying.

Where Polyurea is sprayed over Geotech style and used to line a large pit like this. In many water treatment plants, they will process this water. To. Drinking water category. In these cases, +tank +coating that's being used. In the process is going to have to have an SIRC NSF sixty one point five approval. And these can be obtained from several US testing labs, NSF, Truesdale, United Labs and others. Outside the US, you have the standard Council of Canada, which will accept the US testing.

But if you go into Germany with the eighty 681, that's one of the Dutch, the Australians. Then they may have different protocols for the testing, so it's important to make sure that if you're working in another country, that your certification. The product you're using has been certified in that country. Now, where is where's potable water approval needed? Any of the pikes? Including if you look at the top of this slide, you'll see support pipes.

These will have to be coated with a portable, waterproof material protection barriers, any of sewer coatings on the walls, the ceilings, the floors. Your joints and sealants, if they're going to be exposed to the water, need to have a. Mechanical devices replumbing. Basically, anywhere drinking water will come in contact with whatever surface. OK. Potable water testing is done to identify any short of long term effects emanating from the composition of the coating. The counting is submitted to these independent labs for testing.

And they will measure over a period of time. Any contaminants that can come out of that "deck coating" into the water? Typically, these are done at twenty three degrees C laboratory conditions. It can also be requested at higher temperatures, for example, 30 degrees C. Because we know that most of these plants are not run at laboratory conditions and will heat up. In the sun, in the summer, etc., and this can have an effect. When you are.

Reviewing a polyurea coating system. You will notice that the reports will come back. And it will provide certifications based on a particular temperature as well as it may indicate the minimum "deck coating" area. And dilution factor. In other words, if a thane coating. System. Is evaluated, it may have certain contaminants coming out of this coating. But if it's used in a system that is five hundred thousand gallons, for example, the dilution factor. Maybe such that that particular accounting can be used.

It can't be used at lower volumes because then the the limits of the contaminants would exceed that of the certification. So. Recommending that one doesn't just take the certification as is, but looks at what the values of that certification are. Certification doesn't end with just sending a product out. For evaluation. Once that has been certified, then the specific equipment used to manufacture that product must be certified. So, for example, if you have two reactors and you certify that one.

You cannot use the other without being certified. Record keeping by the manufacturers critical. So that if there's any questions, go back to the manufacturer and find out. How that material was processed and evaluated. And there's always retesting and oddity by these facilities, by these organizations. Because it's been "patio waterproofing" does not mean that a potable water polyurea. Does not act and provide the same performance as a non portable what is polyurea. It's not going to great in the movie, the performance will remain the same.

Some color variations, possibly, but the performance remained steady. It can be sprayed on a wide, wide range of CSP profiles. It's going to resist cracking. Still flexible and as flexible curing requirements, in other words, if you recall from our previous seminar, this can be applied down 20 degrees Fahrenheit, over 100 degrees Fahrenheit. And in high humidity, the atmosphere's. And it can have a wide range of coding thicknesses depending on the specification. These can be done in one pass.

And it will extend the service life. Of the system. Let's look at a couple of examples. This is a 60 year old tank, five million gallons. And you can see on the bottom left the tank prior to any work being done on it, you see there, it's a open-top tank. We have the steel pipe coming in from the concrete. And. Clearly, this was beginning to deteriorate. So that was specified in Polyurea and in this case, portable water polyurea as well as you can see in the center slide, they installed a roof with the supporting poles, et cetera.

This is a good example where Polyurea is very compatible with both the steel and the concrete services. And. As a result, on the right side of the screen, you can see that this using Polyurea allowed this existing structure. It was out of compliance. They returned to service with the current regulations. The next is desalinization plants. Israel is very, very strong on developing these plants for their water supply excuse me, in this case, this project was over a half million square feet.

And they wanted all of the services in the pipe, water storage in the treatment section to have a portable water floor coating. Are part of a what is polyurea was used. And went over all the variety of substrates, the concrete, the steel, et cetera, and they're expecting at least a 20 year, five year service life in this desalinization plant. OK. Moving to another area. UV treatment. Is beginning to gain much more approval. Around the country is it replaces the chlorination and chemical process steps, those steps are used to disinfect.

And to destroy microorganisms, pathogens, viruses, molds, et cetera. The movie clearly is a cleaner method of doing this because then you have you don't have to go back and treat for the chlorine or disinfection contaminants, etc.. The problem is that this is an extremely intense you see Balts that a place within the process. Three. And. The water can be no further away than three inches from each boat. This extreme you've intense like. Is very destructive to, for example, foxes and urethane coating, they'll begin to break down in a matter of months.

And as the maintenance crew are cleaning the walls of the algae in the dirt, what have you. Then the coyotes began to become brittle and break off. There have been some unique enhancements to Polyurea, which allows the use of these products to be used in these systems. You may see darkening or even black surfaces of the [polyurea coating]. But you maintain the integrity of the coding, including through the wash cycle. And you will extend that coating. For much longer than other options.

OK. A very general Comus comment right now on costs. And we will be coming out with some more detailed information on this and future seminars that we hope you'll join us on. Most people, if they're looking at Tank coating. They're going to ask, what is it cost per gallon? And for a lot of people, that's the end of the discussion. Now, without getting into any pricing information here. Polyurea can be about the same or even in some cases lower per gallon than some of the other systems.

However. In most cases, the specifications will require a thicker coating. And there we went through the reasons for that. But if you have a sick "deck coating", then. Multiply that difference in thickness and you say, oh, Polyurea is more expensive. In addition, many of the engineers and designers. Have a preconceived coding budget, either it's a budget that they've used in the past. Orange, the budget they put in today for a process that's going to be instituted in two to three years.

So we need to look at much more than just the cost per gallon of the system. And one of the big things is downtime. Most of these plants are continuous operations and most of them are at near maximum designed. So if you're having to shot a tank or a firefighter down in the middle of your process. It's going to be OK. Something has to be done with the water that would have gone into that tank. You can have a lot of problems diverting these processed liquids and you can have a lot of operation instabilities as you do this maintenance.

So therefore, you want to have. The shutdown, the the preparation and the counting of that day as short as possible. We're the pure polyurea of this can be done. There's a good example of a clarifier outside the United States that was done with Polyurea and from the time the water was drained till the time the tank was clean, the surface was prepped. The Polyurea was put on the service and it's returned to service. It was all done within less than 48 hours.

[polyurea coatings] service typically be back in service within four hours of coding, depending on the formulation of the Polyurea and also the composition for. Looking at other systems, some of these pipeline coating systems can require the non polyurea ones can require twenty four hours between Ricoh and maybe even up to a week before it can be returned to service. So you can see your cost savings of "poly urea" system and these applications. So in summary. Pure Polyurea offers very good solutions for a very large variety of protective coatings in a water treatment plant.

We talk about the last American qualities, the ability to bridge cracks. We talked about single application. Of building a high school coating without allowing. Or without incurring. Dry times before other occasions. The steel and concrete interface. Polyurea matches the CLTV, the Professional bed liner thermal expansion for steel concrete very closely. We talk about reducing the downtime. And we talked about the Polyurea, there are many polyurea options that meet the NSF sixty one point five standards.

And finally, we talked about the extended service life of these codes. So I want to thank you very much for your patience and for your understanding of our initial technical difficulties, and I will turn it back over to Mike and Doug once again.

Thank you all for attending. If you'd like to contact either me or Mike directly, we've provided their phone numbers. And once again, thank you very much. It looks like we had a very big audience and a lot of interest from folks interested in using Polyurea. So without further ado, I say goodbye to you all and look forward to seeing you all in our next next webinar. Thank you very much.

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