Bruce Leavitt Presentation On Trompe Technology

pleasure to be with you today and hopefully we can explain this incredibly simple technology in a way that you can relate it to to your constituency and to folks who me you may come across before we before we go too far if we Kim and I really need to thank you folks for all the work you've done over the years in helping us to develop passive treatment technologies throughout the Commonwealth there have been over 300 publicly funded passive systems built that have improved hundreds of miles of stream but I think there were no we need to to recognize the Good Samaritan Act growing greener the Act 13 funding because that's how these systems get built we are still left with over 5,000 miles of acid mine drainage impacted streams that can benefit from passive treatment systems or active treatment systems as the case may be that that need to be addressed and you know guess the goal that we all share having clean water in the Commonwealth as was mentioned in the introduction some years ago I did some mapping on the extent of mine flooding in Pittsburgh coal basin and this map shows the Pittsburgh coal basin this is the Ohio River here pittsburgh is actually right up here Monongahela rivers is down in this area each of the circles that you see on the map represents of mine discharge and these are primarily although not exclusively from underground mines the areas that are shown in blue these are lines that are flooded the areas that are shown in is this brownish color our active mines where they were at the time and the areas that are shown in gray are either uncluttered or we don't know what their status is what I need to draw your attention to are two circles the diameter of the circle is proportional to the amount of the discharge in other words the bigger the discharge the bigger the circle so a circle that is this size represents a thousand gallons a minute into its light blue in color it's an outlander discharge if it's green in color it's around neutral and if it's red in color that would be in a city discharge as measured by the alkalinity or acidity of the water waters that are circum neutral or alkaline can have the potential to be treated passively and as you look at this graph at this map you can see that the bulk of the waters that are shown are indeed light blue so even though these may be huge discharges they have the potential for passive treatment within the map we have almost 5,000 acre square miles of mine land of which almost 2,000 square miles are flooded this represents one point three six trillion gallons of water that is in storage in the underground mines we're currently discharging about 27 million gallons per year and 63% of that does not go through treatment this would be water that's coming from legacy sites the legacy in this case being mines that closed prior to the Clean Water Act or the surface mining control and reclamation act of this 38 almost 30 percent acidity is untreated 40 percent of the iron is untreated and 90 almost 100 percent of the aluminum that is for his presence is untreated there's a reason for those variations and the numbers and it or insight on that and be happy to tell you why but this isn't a yard to the Trump yet just an example of some discharges here mrs. Cole run you can see the orange staining on the on the rocks this orange represents iron and this is a circuit of neutral pH the Presto cyan discharge we're seeing white staining on the rocks and this is representing this is representing aluminum that's coming out of the water so to the topic what is a Tron it's a device that uses fallingwater to compress air it has no moving parts does not use any electricity and it's completely passive so how is this possible well we have Trump has a vertical pipe and water falling down that vertical pipe in trains air bubbles the velocity of the water carries those air bubbles down so the velocity is going down faster than the air bubbles can go up so the air bubbles are carried down the I'm gonna flip back and forth between a couple of slides because they'll make easier Enders so here's our vertical pipe coming down the air bubbles are carried down and down here the air bubble is separate and float to the top and are captured in these air chambers the water without the air in it travels along the bottom and moves over here to the discharge so as you can see it's completely a flow through device with the only contra being you have to train the air particles and that is accomplished by the air injection head here which creates a bit of a venturi effect which allows the air to be sucked in and entrained in the in the water flow so as we saw in the diagram there follows down the pipe the separation chamber separated by gravity beers collected and waters that discharged the trunk itself is not a treatment it is an air compressor and it allows us to compress the air to a pressure that is sufficient for the needs that we're going to apply it to which is going to be aired the aeration of the pond the length of this pipe dictates the amount of air pressure that we're able to achieve longer the pipe degrade of the air pressure fortunately for our purposes we only need to have a pipe that is less than 13 feet long we typically lock are ideally would do our aeration in 10 feet of water and we have to have a some additional pressure generated in order to operate the the air diffusers Trump's tendon operated a bit of a narrow flow range as dictated by the diameter of that down pipe so if you we need to know what the what the flow rate is at a particular site in order to be able to design the system to accommodate the range of flows that we're going to see some the next site that we're going to look at ranges for about 25 gallons a minute up to 150 gallons a minute and at that site it was necessary to have the Reaver turtle place in the system so that each one would handle up to 50 gallons a minute and if we were just operating one it could operate at 25 but not any lower than 25 the other thing that's important to note here is that we can generate one cubic foot per minute of air for every 25 gallons per minute of water I apologize for the mixed units but it's easy for us on the English system to understand how much air is being compressed okay this is at the Norfolk site it has recently been installed under a grant from the office of surface mining to develop this technology and this is the site that never ever mentioned we have the flow range so the lowest pipe this one right here it sees the water first and it sees the first 50 gallons per minute so it starts operating and as the flow increases then the next Mountain Lake starts operating and then the third leg starts out operating so it starts operating so that we end up in total with 150 gallons a minute of flow being generated we have also demonstrated at this site that is possible to use the water over again we have three Trump's that are in series so this Trump is here we have another Trump that is located right there and the third Trump is down here so by running them in series we are able to multiply the amount of air that we are generating from the same amount of water so three times three Trump's three times the air or the same flow rate the Trump is originally developed in the 1600s 17th century probably in Italy but it was really picked up by the Spaniards and became an integral part of what as known as the Catalan Forge and they would have their vertical pipe which would probably have been maybe a hollow tree and they would cascade the water down and it would be caught in this air box and the air would then be directed into into their forage instead of having a balance and you may have heard of Catalan steel in the past but they're quite noted noted for their steel making many centuries ago in fact the Spaniards brought trompe technology to the United States and built a couple of cattle and forages in California well that technology was kind of lost for a time and a fellow in Canada by the name of Charles had luck Taylor rediscovered the principle when he saw water coming over a waterfall and in training the air and creating blisters and bubbles in the ice that was on the surface of the water and he connected the dots and started building these things and he built massive props the biggest one ever built was at ragged chutes near cobalt Ontario and as you can see possibly see from the diagram this vertical shaft up at the top that vertical shaft is nine feet in diameter it went down 345 feet now obviously they are using miners to build this not excavators right the horizontal section where they separate the the water from the air is a thousand people on the return pipe this point two feet in diameter and 298 feet 298 feet long they diverted the Montreal River into this thing it generated over 5,000 horsepower it was able to compress air to 128 psi remember I told you the length of the return pipe dictates the amount of pressure you generate so that's this length the return pipe was able to generate 128 psi it operated for over 70 years and was taken down only twice for maintenance the compressed air from this trunk was piped to the silver mines around cobalt Ontario where they used it to run the rock drills you know pneumatic hammers and you know as a side benefit the miners got some ventilation so getting back to denying drainage when do we have to have aeration in my drainage what we need aeration when ferrous iron is present the orange stuff that you see is ferric iron so we need to convert ferrous iron into ferric iron and you do that by adding oxygen you also have a need to add air and oxygen when you have a low dissolved oxygen content typically water comes out of some of these underground mines very close to zero do I mean point o2 or very small numbers the third time you would need to air it is when you have dissolved carbon dioxide in the water and the effective carbon dioxide is the lower the pH of the water to make it more acidic because it dissolves that's carbonic acid in the in the flooded underground mines you have a an environment where acid in the mine water can react with calcite that may be President and the rock dust or in the rocks surrounding this generates this race of the pH but it also releases carbon dioxide and that carbon dioxide can dissolve in the water pushing the pH down of it so if we can remove the I'm sorry remove the carbon dioxide from the water we can raise the pH of the water that's raising the pH is part of the treatment that is necessary and a number of these paths of my drainage systems so in this chart the key thing to take away from them is that as the pH Rises the amount of time that it takes aren't oxidized diminishes from years the months to days when you get up here in the vicinity of pH 7 it only takes minutes for that to happen so instead of having to have long retention times for the reaction to occur if we can get that pH up here 7 we can make that happen a lot faster so we started doing aeration tests this is a this is the Curley site it's the first time that we put a trough into and all this is is we have on an aquarium aerator an air compressor with a little sparking stone inside a column of the raw my water we grab it as soon as that comes out of the mine and as you can see just by blowing air through it we're able to raise the pH from 6 up to 8 this means that by getting air into the water we're taking the carbon dioxide out we're exalting the carbon dioxide and we're simultaneously putting oxygen into the water this this is another site that we've recently put a grant proposal together on act 13 or act 13 money this is a very high volume discharge that has a very small physical area available for treatment and one of the benefits of using the Trop technology is that you're able to minimize the size reduce the size of the treatment system necessary because you're able to speed this process up and again you can see here that we're going from a pH of about 6.2 to 7.3 and the next graph what I want to show you from this graph graph is that this is technology is not limited to the bituminous pole areas this is also applicable in the anthracite the Old Forge discharge is a huge discharge coming in to the lack of water River and you can see that again over time we were able to raise the pH from six point two to six point eight now this is the curly discharge and this is the raw water that's coming into the system and you can note that the water is crystal clear that's because the iron is completely dissolved in the water and is very content to stay there until you start changing the aeration of the water and down here at the bottom this is the air that is bubbling through the water that air is being produced by one of the Trump's that we have built at this site and we are beginning the both the process of exalting the co2 and dissolved dissolving the oxygen into the water apologize for the chemistry but very simply if you have ferrous iron at a 1/4 mole of oxygen consumed a hydrogen you basically get your eric iron and water if you do the if you do the chemistry you do the math basically it means that if you add 1 milligram of dissolved oxygen you can oxidize 7 milligrams of ferrous iron and as we learned it's a time-dependent reaction so here at the Curley site we saw where the raw water comes in and we're looking at the dissolved oxygen content here and it falls into a plunge pool which takes it from essentially a 0 to 1 milligram per liter right at this point we have the the trough aeration taking place and immediately after the Trop narration we've moved it from 1 milligram per meter to about 6 and 1/2 milligrams per liter now if we add additional aeration there and we did but didn't measure it you can obviously take the do up to its normal saturation level which is about 10 - 10 to 11 milligrams per liter depending on temperature at the same site we can see that as it's flowing through the system the pH of the system is also rising we were able to raise the pH from about six point three to six point six so we're able to raise at three tenths of a pH unit just flowing past the past two Trump aeration this is a picture of the currently site from the opposite direction you can see this is the raw water coming in and this is the aeration taking place the physical location of the bridge is right here so we are measuring pH or raw water pH and the plunge pool at pH right here at the bridge so that's where the where our controls on the system are now now you notice the color of the water we're starting we're starting to get a greenish kind of color here becoming a little bit opaque and over here in the next pond these but flow this way and then back we see the bright orange color that we normally associate with with the mine drainage when this discharge was running without the air on both plots are crystal clear we hadn't even started to oxidize the the iron yet and so we were having problems at the discharging of the treatment system because the iron wasn't coming out as it needed to I'm going to draw your attention now to to the size the amount of air bubbles that you're seeing there this flow rate is about 60 gallons per minute and is coming from a single trunk the next photo is from the North worksite and this is coming from three Trump's in series at 125 gallons of it and you can see the significant increase in the amount of air that's being bubbled through the system the amount of the air that you can transfer is a function of a number of factors one of which is the size of the air level if you have a big buck air bubble you have a certain fixed surface area but if you take that big air bubble and break it down to a bunch of little tiny bubbles you have ever so much more surface area and it's that surface area that controls the transfer of either the carbon dioxide or the oxygen between the gas and the water phase so it's important to have a fine bubble aeration we accomplished that aeration using a disk area these discs have very tiny slits in them and the slits allow air to bubble through and make very fine bubbles as they do so these discs are off-the-shelf technology and they are used in sewage treatment systems because you know in a sewage treatment system you have to aerate on the anaerobic step any dairy to keep the bacteria moving and eating up eating up the discharge unfortunately and in a situation where you're oxidizing iron the iron could start to deposit on the disk which is represented here by the the ugly one this these disks can be easily cleaned using hydrochloric acid and you can either remove them from the bottom of the pond or actually treat them while they're still in the pond we've got we've developed technology or methods for treating them and either either scenario the other thing is if as if you double the depth you double the oxygen transfer for the same amount of air so we try we try to work at 10 feet going deeper than that becomes impractical to dig the the hole that's necessary for the trough shallower than that and you're not getting enough bang for your buck just a couple of graphs of what we were able to accomplish at the Curley site this percent iron oxidized started off with a zero the orange line represents no aeration this is what the system was doing prior to building the trunk the middle line we were in love with the Trump was running but at low flow so we weren't getting the max the maximum amount of air coming out of the system and the Green Line is fully aerated everything working properly and you can see that we've by the graph that we're able to more rapidly oxidize the iron as it moves through the system some more results the amount of iron settled the colors remain the same red being not aerated the bluish color partial aeration and the green color to the Trump operating correctly basically at work before able to oxidize that we're able to settle it so one of these things cost well it's a function of size we typically build these out of PVC pipe and for the smaller flows you can actually buy the pipe that you need at Lowe's or Home Depot as you into the larger flow rates you have to go to the specialty plumbing houses that have the 10 12 14 16 inch diameter pipes that are needed and the costs for those size fittings are remarkably different from what you're used to seeing at Lowe's and Home Depot so for a flow rate of 20 to 100 gallons a minute you're looking at about twelve thousand dollars to do a turnkey operation by the kind of stuff into the site bring the excavator in dig the hole assemble it and plug it into the into the site height of plumbing as you get into bigger flow rates you're looking at you know additional additional not somebody needed to to build the system then I switch years now a little bit and talk about a semi-active lime dosing system and this is a at the manor site and it is a couple quick line system that uses a water wheel to distribute the quick lime the problem with some of these waterwheels is this lunge accumulation this is this is undissolved line this is lime that is put in the system but never was utilized because just didn't dissolve tim had a great idea and that was to use a by the way this is this is what pebble quick line looks like when it comes into the facility and you can see they're large lumps in there and they're finds it's all mixed up together Tim came up with a mix well concept in which mine water flows down into the bottom of this vertical pipe and the pebble quicklime is added along the outside and this creates a bunch of turbulence down at the bottom the pebble quicklime falls at the bottom and gets rattled around and we call this an autogenous grinder a self grinder and as a result this is able to degrade the pebble quicklime into very much smaller particles this is a picture of the mix mix well in action the lime is being fed in here and dropping down and we're all waters coming down the center pipe and the overflow like going this way takes the the mixture downstream and as you can see from this picture here those line particles have been significantly degraded to a much smaller size but we still want to get the value from this line as well and so I came up with a concept of the a mixer and in this concept we are using air from a trompe which is being fed down the center of this pipe and it's this this is a vertical pipe that is suspended off the floor and below the surface here from the trompe does allow it to bubble down the bottom of the pipe lowering the the density of the water in the pipe the denser water on the outside force its way in and you generate a circulation this circulation allows those particles to remain suspended while they continue to dissolve and this gives you a view of what that looks like in action where you have the air causing this bubbling that is a welling of the water in the center and continued mixing of the the water entertained just for jollies you may notice that this water is green iron comes in two colors Paris is green and affair is orange and so we have a lot of ferrous iron and as we bubble air through it we are also starting to oxidize the iron at the same time that we are continuing the mixing of the the pebble quicklime and this is a picture of the pebble quicklime after it's gone through the mix well and and the a mixer and you know these are grass the particle size distribution basically the we put the material through SIVs and the raw material sixty percent of it stayed on on the ten mesh sieve and very little of it was fine by the time it came out of the mix well we had eighty percent a hundred percent one through the ten minutes and eighty percent was retained on the 60 mush and by the time of lefty a mixer these are two different days here when we did the test we're between forty and fifty five percent retained on the 60 and and again about 50% retained on the 80 so we're continuing continuing to utilize line of what does what this translates into is a 40% reduction in the cost of lime at this treatment site which is being managed under an edema the Shannon DMO is basically paying for this so this is these are Commonwealth dollars that are being saved okay so what other technologies what other applications might there be for trompe technology obviously we have line graded treatment and that can be either active and passive there are a number of active sites where mechanical aerators are used and people are spending money on electricity in order to aerate the water where they have a flow that could drive an air compressor that would save them the cost of the electricity and the cost of the maintenance on their mechanical system clearly sewage treatment as a possibility if you have a water level difference by the way I guess I never mentioned it we need four feet of water level difference in order to drive one stage of a Tron if you have that discharge on your sewage treatment plant you can run that through a trunk and then take your air back to the to the aerobic bacteria step and either replace or reduce the amount of mechanical aeration that you have to use you can use it in aquaculture fish need agreed right and if you have a lot of fish end up in a small area if they may I expect they would grow faster if the do levels were high late narration some people use it for algae control and obviously you can use it for for chemical mixing and I was thinking after I did this you know there are a number of streams on the impaired list for the Commonwealth that are impaired because of low dissolved oxygen so the pay the pay off there may not be great because low go low do sections of stream typically don't have a lot of gradient they're flat and of course we need for p2f but you know there may be we may be able to bring in side streams or there are lots of possibilities to consider so I'd like to acknowledge Tim and bio most because they they stepped up on curly and they saw the benefit of the technology early on Tim who will happily do anything in January Brian Paige who the man is amazing he'll walk right into a a yucky sludge filled pond in January and also will need to acknowledge Cody so at this point happy to take any questions you may have

Channel: PaEnviroDigest

Views: 9,014

Rating: 4.8350515 out of 5

Keywords: Technology (Professional Field), Trompe, mine drainage treatment

Id: TuaxjR3TQkQ

Length: 37min 2sec (2222 seconds)

Published: Tue Oct 22 2013