I arrived on the scene at Leckie Smokeless on November 27, 1978. My knowledge of water treatment and acid mine drainage at the time was merely that I had heard of it. However, during the next few weeks I was introduced to a device up on the mountain that treated acid water. This device would soon cause me to make up some new four letter words. It was an automatic (float-activated) sodium hydroxide dispenser. I could not get the thing to work right. The water in the test tube was always purple or red and the guy from DNR kept telling me it ought to be green. This was my initiation to water treatment and for those who are curious, it wasn't long be-Fore I took a sledge hammer to that device and replaced it with a valve for drip treatment.
Three or four years passed by rather quietly and then BOOM! All of a sudden, Buck Lilly was born. Buck Lilly was the name given to our refuse site in honor of the gentleman who previously surface mined the area. We had been dumping our refuse in an unreclaimed pit and I never suspected there could possibly be any water problems. The floor of the pit dipped back to the wall, the spoil material in front was a calcareous shale, and I really hadn't had a bad problem anywhere on the property. But Murphy said "this guy is just right, let's get him". So, Buck Lilly began to discharge acid water from several seeps at the toe of the refuse area. I began a fast and furious treatment program with the enthusiastic help of Ben Faulkner, our previous DNR inspector who had found the problem. We hired Ben to solve the problem he found. No matter how hard we tried, nothing worked. I blew tankers of lime in the pond, pumped in tankers of sodium hydroxide, and even tried flocculants. But nothing worked. We could get the pH up but we couldn't precipitate the iron. It was obvious to Ben what the problem was. It was the discharge pipe. It wasn't discharging water from off the surface of the pond. So he waded out into the water up to his shoulders and beat the top of the pipe off with an ax. To make a long story short, the pond was equipped with a perforated riser and the acid had eaten out the bottom causing the pipe to act like a vacuum cleaner sucking iron sludge from the bottom of the pond and discharging it into the stream. Needless to say, cleanout costs at the pond had been minimal so far. I immediately learned that from then on, all ponds would discharge water only from the surface whether by T-skimmers, sluiceways, or some other surface skimming method. Once the true problem was discovered, the perforated riser was completely torn out and replaced by two 24" PVC T-skimmers. It was as though we had won the lottery, BINGO! The water was perfect, or so I thought.
Since the problem was solved, we set up two 3000-gallon sodium hydroxide tanks on the hill above the pond and ran a hose down to the entrance channel. Control of NaOH flow was by a manual valve. All went well until the valve broke and both tanks (or 6000 gallons) of sodium hydroxide went into the pond. You guessed it, I had both tanks plumbed together -to last longer. Fortunately, all of it went in the pond. Unfortunately, 20% sodium hydroxide has a specific gravity of approximately 1.2, meaning that most of the stuff was laying on the bottom of the pond. Well, as Murphy would have it, this all occurred on a weekend. When I checked the pond Monday morning, I was discharging bad water and who rolls up on the embankment? Naturally, my inspector. Well, we knew that there was plenty of NaOH in the pond but it was just in the wrong place. So we got some primers off the strip job and began to have a ball trying to mix the stuff up. As might be expected, this didn't work, but by then the NaOH truck had shown up and refilled my tanks. That was great because we immediately started treatment again. But there was still one problem. The pond was still bad and the discharge was awful. To treat the whole pond from the entrance channel would probably take several days, so we got the hydroseeder and tried spraying lime on the pond. We even threw gallon jugs full of sodium hydroxide out in the pond. Does any of this sound familiar yet'? We finally got the pond back in shape and made a pact that we would never go through this again.
Fortunately, another employee, Gene Keaveny (Dr. Gene) came up with a brilliant idea. Gene purchased three $6.99 lawn sprinklers (the type you see on the golf course) and hooked them up to the sodium hydroxide tank. He dispersed them across the pond by floats made from tubes, styrofoam, milk jugs, etc. When Gene turned on the valve, we were totally amazed. The tanks were high enough that they produced sufficient head to cause each sprinkler to cover a 50 foot diameter area. Since the NaOH had a specific gravity of 1.2, it treated from the surface down. From then on, if we had a mishap with our regular treatment system, we could be back within effluent limitations in an hour and a half. You need to remember that this pond is 400 feet long, 150 feet wide, 10 to 12 feet deep, and has flow rates up to 600 gallons per minute of water with these characteristics:
|
pH |
- 2.8 |
|
Acidity |
- 5,000 mg/l |
|
Manganese |
- 350 mg/l |
|
Iron |
- 1,500mg/1 |
|
Aluminum |
- 600 mg/l |
At that particular time, 20% sodium hydroxide cost between $.35 and $.40/gallon and my water treatment costs were continually escalating. In addition to reagent cost, my pond would fill up with a gross looking sludge and I'd have to spend $15,000.00 to lease a mud-cat dredge to clean the pond. I figured there had to be something else out there to help me with this problem. That's when Roger Hall introduced me to surfactants. I got in contact with several people who sold surfactants (soap) and they told me that tiny bugs were my problem and I could clean them up with their soap. Now don't that beat all. After being educated about Thiobacillus bacteria and after many leaching tests had been performed on my refuse, I decided to try the surfactant offered by Andesco Technologies. Jim Greskovich runs Andesco and is a super guy to work with. During the next few months, Jim spent his time instructing me in the technical aspects of acid mine drainage. All his tests proved that the payback would be in the form of reduced sodium hydroxide consumption as we continued surfactant treatment. My cost records have proven that point to this day, but there was always something that bothered me about the way we initially applied the Antec 128. Jim would come to Leckie every two months and we would spray the entire dump. This was fine except, based on the leachate tests, this didn't make the most sense. All the leachate tests proved conclusively that treatment of refuse with surfactant as it came out of the prep plant obtained the most optimum results. When Antec 128 was applied every two months, the refuse produced a range of good to bad water depending on the length of time since treatment. By treating the refuse at the plant as it came out on the belt, water quality improved considerably, there are a few catches to this procedure, but I don't want to take up time in this paper to explain them call me.
During my soap phase, the state introduced me to my soon to be mentor in acid mine drainage: Dr. Frank Caruccio and his wife Dr. Gwen Geidel. These two people probably helped me more than all the others put together. The state of West Virginia was kind enough to include Leckie in it's research concerning AMD, and Dr. Frank and Dr. Gwen visited me quarterly. We began the project by trying to define the groundwater system within the refuse dump. The doctors would send me a list of things to do and we would do them.
By the way, that's how Gene got his title. He was doctored by the doctors. I learned much during my association with Frank and Gwen and I will always be ever grateful. Upon completion of their project, I was still looking for a cheaper way to treat the water. It didn't look as though I could now economically remedy my problem but only search for cheaper ways to treat. Along came some guys who wanted to "zap" my pond.
Two gentlemen, who heard through a friend of a friend that I was always looking for a new way to treat water, approached me with the idea of using electricity to treat the water. This was an appealing idea so we met. They informed me that the technology was not new, but previous tests had utilized the wrong type of______________. Sorry, I can't tell you. I signed one of those confidentiality statements. After much planning, we agreed on the best course of action and assembled our own set up by using spare parts and cables from the deep mines. The only thing that we had to purchase was the_________________. We hooked the device up and from the air it must have appeared like a giant spider had spun a web across the pond. With everything set, we threw the switch. Zap - Boom - Kapowie! After burning up and blowing several transformers and resistors, we figured out the load on the system and adjusted accordingly. We hit the switch and the pond began to bubble like it was right out of a monster movie. The system was absolutely safe unless you got between an anode and cathode. This happened to a few unsuspecting creatures (bugs, frogs, etc.) and it was not a pretty sight. For some reason, within a day or two of assembling this puzzle it became imperative to clean the sludge from the pond. Before I was able to get to Buck Lilly, the crane had been moblized and, not knowing what all the cables were doing in the pond, hooked on and swung the whole system over the hill. You could have retired trying to figure out how to untangle all the knots and snarls. But we perservered and were able to salvage bits and pieces. Since the remainder of the system was not very large, I used it in conjunction with sodium hydroxide. Before I leave this system, I want to say that I believe it has potential and I wish those two guys the best of luck in their endeavor.
It was now 1987 and I attended the Surface Mine Drainage Task Force Symposium held in Morgantown. At this particular meeting, Dr. Caruccio gave a talk concerning the possibility of pumping treated water back through acid-producing refuse or spoil. This idea hit me like a bolt of lightening! In a sense it would be like treating with surfactants only in the opposite direction. Surfactants depend on an acid environment to kill the Thiobacillus bacteria, whereas alkaline water would raise the pH of the system putting the little suckers to sleep or into a dormant state. I went home from this symposium ready to pump, pump, and pump. Unfortunately, I didn't have a pump. Well I put this idea on the back burner for a while and continued status quo. By this time there were rumors that sodium hydroxide was going to take several price increases. What an understatement! Along with these rumors, the boss wanted me to find a different chemical to treat the water in the preparation plant. Leckie produces a high grade, mid-volatile coal which goes to Europe for steel making. The buyers of our coal were complaining that the sodium and potassium content of the coal had to come down. The potassium acted as a catalyst in the coking cycle and the sodium was leaving a residue on the walls of the furnace. Because we used sodium hydroxide in the plant, excess sodium was making its way to Europe in our coal's moisture content. So I set out once again to look for an alternative.
While looking for a replacement, I ran across a material called solid caustic. No, this is not flakes or powder but a 75 lb. pony keg full of solid NaOH. The caustic is actually poured into these drums while in a molten state. The fact that I wasn't paying to transport water (as is the case with 20% sodium hydroxide) really appealed to me. The next step was deciding where and how to use it. The where part was easy. I was using briquettes at several locations on the property and I was fed up with the handling problems. Although the briquettes came in plastic lined bags, they were still prone to moisture and would disintegrate unless stored inside some type of structure. Also, they were extremely prone to rat-holing which required continuous attention. I bought ten drums of the solid caustic and went to work. The drums were metal and had sealed lids so I could set them out in the weather or wherever I wanted. Based on my consumption of briquettes to drums, I reduced my treatment costs at each site by 30 - 50%, and material handling was considerably easier. At the time, I was paying $7.50 a bag for briquettes and $40.00 a drum for the caustic. In case you are wondering, Jim Greskovich with Andesco is the distributor for these drums and has developed a very simple but effective system for their use. In my earlier days of experimentation, I used a sophisticated technique in treating with drums. I'd break a limb off a tree, stick one end in the water I wanted to treat and the other in the drum. I'd then punch a couple of small holes in the drum and regulate flow volume by how far I stuck the limb in the water. Slightly rotating the drum once a day eliminated rat holing. Isn't it amazing how college prepares you for these scientific challenges? I definitely recommend that any of you using briquettes call Jim Greskovich immediately.
Well, back to the search. I recalled that several people had previously mentioned trying anhydrous ammonia but I had shyed away because of the potential environmental problems I'd heard about. However, my options were running out and with the price increases in sodium hydroxide, I had to play or pay.
The age of ammonia dawned for me in 1987. 1 took several trips to look at other installations and read all the literature I could find concerning any and all possible environmental concerns. From what I read, this chemical was like any other. If you abused it, you would have problems, if proper controls were administered, there should be no problems. I contacted several ammonia companies asking for quotes and about the possibility of getting tanks. The company that impressed me the most was National Ammonia Company of Philadelphia, Pa. These people were quick to respond to my questions and ready to assist me technically. They knew very little about AMD but they knew a lot about ammonia. Within a couple of days of contacting them, National Ammonia sent down their salesman, Jim Hajek. Jim's a super guy. He helped during all stages of the operation by giving safety talks and sharing valuable information concerning the ammonia itself. Did you know there are two types of ammonia on the market? Refrigeration grade is pure, while commercial or industrial grade may or may not be pure. I could have saved a few pennies by going commercial but I wanted to know what I was treating with and refrigeration grade is guaranteed. The first tank I hooked up was at a small pond close to the preparation plant with low flows. This pond generally costs me about $9,000.00 a year to treat with sodium hydroxide so I felt this could be a good place to get my feet wet. I injected $5.00 worth of ammonia in the pond that day and it stayed treated for a week. At that point I learned how extremely concentrated and potent anhydrous ammonia was.
From this initial pond, I went to Buck Lilly and installed three 1,000-gallon tanks in parallel and hooked the pond up like I had seen at other sites. Every NH3- treated pond I had seen elsewhere had floating injectors on the pond operated by a pH controller at the discharge pipe. When the pH reached the low set point, a solenoid valve opened and released ammonia until the upper set point was obtained. I soon learned that this type of injection method could cause potential problems. Since I'm in the engineering department, I really don't do anything (Ha Ha) so I had plenty of time to evaluate how the ammonia reacted. I would sit for (it seemed) hours and watch how the ammonia would disperse through the ponds. I have not seen any other chemical do this before. It was as though the ammonia was searching for something to react with. While watching the injectors operate, it occurred to me that since ammonia was continually being dispersed from a single source when the valve was open, the water must vary in pH from the discharge point back to the injector. obviously the water is quickly treated immediately around the injector, so continued treatment must mean that an aqua solution of ammonia is building up and spreading away from the source. To make it plain and simple, the pH probe at the discharge shut off the valve in the middle of the pond when the upper set point pH was reached. However, a large amount of water between the injector and the discharge point was overtreated. This super highly-ammonia-treated water would reach the discharge pipe and exit the pond. What complicates this phenomenon is the fact that ammonia is lighter than water and will rise towards the surface. If you have only one pond and are treating it injector style, you will only be treating the surface and are prone to dramatic quality variation based on weather events. on the other hand, if you have several ponds in series the problems are not as severe.
I still believe using an injector system is not efficient nor prudent in most cases. In noting all these problems, I decided that ammonia should not be any different than sodium hydroxide. To maximize the efficiency of any chemical for treatment it should be used continuously and only to the extent necessary. Keeping that in mind, we set out to install an injector that would operate continuously in the entrance channel of our ponds. Initially all our attempts were futile due to a very simple problem that I kept overlooking. The problem was so bad that I was ready to give up until I saw what was happening to sodium hydroxide prices. In June of 1987, 1 was paying $.27 per gallon for 20% sodium hydroxide and by December 1988 the price was hovering around $.50 to .55 gallon. For those who don't feel like that's too bad, if your total treatment cost last year was $100,000. it essentially doubled to $2000,000 this year. Big, big bucks -- huh? With this in mind, we diligently worked on an injector which would continuously and consistently release NH3. The continuous part was easy but the consistent part is what caused us problems. Let me explain! With a manual ammonia system, you will normally have the following components:
Ammonia Tank
1/2" or 3/4" Line
Needle Valve
Check Valve
When all of these components are hooked up and in place, the needle valve is used to adjust the flow of ammonia. The tricky part is that anhydrous ammonia is in a liquid form but begins to vaporize at a -280F. As you open the needle valve to begin treatment, you obviously provide a means for the pressure in the tank to be relieved due to vapor generation for water treatment. The more you open the valve, the more you will begin to see the pressure in the tank drop over time depending on the ambient temperature. In the summer months, this pressure drop is usually negligible. But in the winter, this drop can be devastating. The drop in pressure means that the ambient temperature is not high enough to generate adequate ammonia vapor to meet your demand. Therefore, you will see fluctuations in your water quality when manually operating with a needle valve having a set orifice size. There are three ways to remedy this problem, one of which does not require electricity and two which require at least 220 vac.
Method 1 is really a physical way to minimize the problem. Depending on your water quality this may or may not work. If it is extremely bad and your consumption is abnormally high, you will have to use method 2, or 3, or both. The theory behind Method 1 is quite simple and is related to surface area. The greater the contact area of anhydrous ammonia with the inside of the tank, the greater the vapor generation. Initially at Buck Lilly, I had three 1,000-gallon tanks. I would operate a tank until it was used up and then switch to the next tank. I found that because of my vapor demand, the pressure in an individual tank would drop quickly and force me to another tank prematurely to benefit from the untapped pressure in the full tank. To remedy this problem I hooked all three tanks up in parallel and operated them simultaneously. This took advantage of the inside surface area of all three tanks and offered a more consistent treatment. This did not eliminate the problem but did increase the time period between pressure drops. Another obvious solution is to get a larger tank. Method I is mandatory if power is not available and the raw water quality demands a high yield generation of ammonia vapor.
Method 2 offers the ability for compensation of pressure swings by the use of a proportional valve. As expected, this system requires power and the following:
- all the components from method 1
- proportional valve
- pH controller
- pH probe
A proportional valve responds to fluctuations in pH similar to a metering pump in a preparation plant. If the pH in your entrance channel drops below your set point, then a signal from the control opens the valve up proportionately to reattain the set point. This is entirely different from a solenoid valve so don't even try to compare them. The pH swing in the entrance channel may vary due to weather events or fluctuation of the ammonia tank pressure indicating the use of a proportional valve. Depending upon the quantity and quality of water, method 2 alone may not be enough.
Method 3 involves the installation of an ammonia vaporizer on the tank. The vaporizer is simply a heating element, such as those in a water beater, which is contained in a submarine-like tube. The tube is connected to the ammonia tank to a liquid valve and to a vapor valve. As the liquid passes over the element, vapor is generated which flows back in the tank building up pressure. The pressure is controlled by a pressure switch with a high and low setting dependent upon your need. With the vaporizer installed, a constant pressure may be maintained enabling the water treater to minimize fluctuations in treated water quality.
Obviously the optimum system would be a combination of methods 2 and 3. A proportional valve supported by a vaporizer will furnish an almost perfect pH control within + .2 of one pH unit. However, many of our ponds don't have power available and most of us don't have any money, so method 1 will work fine. Leckie currently utilizes method 1, method 3, and methods 2 and 3.
After implementing the NH3 project we acquired a pump for the Buck Lilly pump back project. Several sediment type ditches were dug down into the refuse dump. The treated water from the pond was then pumped and allowed to leach through the refuse and eventually end up back at what I affectionately call Buck Lilly No. 1 and 2 seeps. How do I know the water was coming back to my seeps? After previously looking at dye and potassium bromide as tracers, there was no doubt what would be the best: Ammonia' The water I was pumping through the dump was treated with ammonia and was easily detected back at my seeps. I pumped from December of '87 through May of '88. The iron and acidity readings consistently dropped during this period. What does baffle me is that the manganese and aluminum seem to be unaffected. Does anybody have any theories? Well, in May I had to quit pumping to the dump because the famous drought of 1988 was beginning. What water I had was treated and pumped to the preparation plant to be used as make up water. This lasted until September. Throughout this period, the iron and acidity contents of the seeps rose back up at about the same rate as they fell. When pumping resumed, I observed the same type of drop in metals as had previously occurred between January through May. Attached with this paper is a graph depicting the results. I plan to continue this project and find out just how low iron and acidity levels will drop.
If you are contemplating using anhydrous ammonia at your site for water treatment, do the following:
| First: | Analyze your receiving streams for existing total nitrogen, ammonia, nitrites, nitrates, alkalinity, acidity, pH, and sulphates. You may be located in an area where the existing NH3 level is too high already and more ammonia could damage the stream environment. This happens in some areas and is sometimes associated with raw sewage, farm drainage, hatchery effluent, etc. |
| Second: | If you found the stream quality low or absent of ammonia, then proceed by performing a Benthic study of your receiving stream. Study above and below the confluence of the discharge and the stream. Contention is that ammonia treatment can cause problems associated with the micro- and macro-communities so it is obviously wise to document your pre-ammonia water quality. Also, there exists a fear that acidity will be created downstream as ammonium is nitrified, but so far this has only been demonstrated in the lab and not in the field. |
| Third: | Find someone who is using ammonia and see if your application of ammonia is consistent with what they have learned concerning its implementation. |
| Fourth: | Request in writing to the state to modify your NPDES permit to include ammonia as a chemical to treat water at your site. Be sure to include your background data to justify your request. If approved, you will be sent DMMR's which require you to sample the stream for total ammonia converted to un-ionized ammonia, nitrites, nitrates, alkalinity, acidity, and pH. Un-ionized ammonia has been proven to be harmful -to aquatic life and, based on limits established by the water resources board, must be kept less than .02 ppm in trout streams and .05 ppm in all other streams. Un-ionized ammonia is calculated by using total ammonia, temperature, and pH. These parameters are combined into an empirical formula (I love empirical formulas) to yield un-ionized ammonia. If the receiving stream pH is low and the water temperature is low, you've got it made. What's low and what's cold? Study the formula and figure it out yourself. |
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| Fifth: | With your NPDES permit modification approved, contact an ammonia company, preferably National Ammonia, and inquire about tank availability and chemical costs. Knowing that you will use x gallons of 20% sodium hydroxide or y tons of hydrated lime, you can take one of Jeff Skousen's Greenlands articles and figure out your ammonia consumption. Depending on what the amount of NH 3 turns out to be, you can determine what size tank is needed. obviously ammonia is like many other chemicals. The larger delivery you can take, the lower the price of the ammonia. So do your payback analysis on tank costs vs. product cost and consumption. National Ammonia has a technical representative named John Adair who can tell you where to get all your hardware -to operate the system. |
| Sixth: | Once you know tank sizes and their locations, comply with SARA Title 3 or "Community Right To Know" by notifying: |
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| Seventh: | Establish your monitoring parameters. I would advise you to establish several downstream sampling points in addition to your permit and monitor for at least: |
|
pH |
|
| Take these downstream results and constantly compare them with upstream samples. | |
| Finally: | Use of ammonia is not for everyone. Only responsible persons who will safely administer and constantly monitor it should be allowed to treat with ammonia. |
| Question: | Is it worth all the fuss to use ammonia? |
| Answer: | Yes. Even with the extra monitoring, Benthic studies, and all else that has been discussed, switching to ammonia from sodium hydroxide reduced my treatment costs by 70 to 80%. |
There are many other areas concerning water treatment and AMD amelioration Leckie has been involved with, but I know you are either tired of reading my jibberish or bored, so I will save the rest for the next segment of "The Magic of Water Treatment". Stay Tuned!
The following charts, graphs, and other information are included to supplement the written text and clarify certain information.
|
Pages |
Description |
|
12-20 |
Leach analysis of refuse and coal seams at Leckie. |
|
21-24 |
Water quality analysis for seeps 1 and 2 in 1985 and 1989. |
|
25 |
Water quality analysis before and after electricity treatment. |
|
26-27 |
Safety sheet for anhydrous ammonia. |
|
28-33 |
Articles concerning medical response to over-exposure to ammonia. |
|
34 |
Iron and acidity values of Seep 1 during pump back project. |
|
35-37 |
Cost analysis between NaOH and NH3. |
SIMULATED WEATHERING TESTS OF SELECTED REFUSE SAMPLES
As discussed in the report of March 21, 1985, five samples of refuse from the preparation plant were subjected to simulated weathering tests. The results of those tests indicated the refuse from the Rockcamp Little Raleigh was strongly acidic, although at that time the tests had been run for only 14 days. On March 24, 1985 a sixth sample, refuse collected from the Pocahontas # 6, was added to the series. The simulated weathering tests were extended to 93 days, with the exception of the Pocahontas # 6 which was run for 43 days. The cumulative acid plots versus time are presented in Figures I through 6. The results of the simulated weathering tests clearly identify the Rockcamp Little Raleigh refuse sample as the major problem refuse (producing 23 g of acidity per kg of sample at a 93 day period). Based on the comparison of all samples, we would rank them as follows (to accomodate sample W 6, all acid production potentials are listed per 43 day period):
Although large size samples were used in the study, 5 to 9 kg, it is emphasized that the inherent heterogeneity of the refuse material precludes a rigorous interpetation of these data. What can be conclusively stated is that all refuse samples have the capability of producing acidic leachates, though to varying degrees. If the samples used in the tests are in fact representative of the field and mine settings, then, obviously, the Little Raleigh is the major problem acid produ?cer and should be selectively handled. However, the distribution of acid production potentials of the Firecreek samples (from 70 mg/k to 1000 mg/k) further emphasizes the variability to be expected and the required moderation in the interpretation of the results.
In general, though, the refuse material may be characterized by these results. Should more detailed and precise data be required, it is recommended that triplicate samples of each refuse source be collected and analyzed to determine the expected variation in acid production between and within samples. In our opinion, however, these additional studies are not warranted by the nature of the problem.
