Transcript [EN]: Wastewater Training, 3 of 3

we'll get the third one up there and we'll have all three on the website for you so at this point you should know jim and today we're going to cover nutrient removal handling of biosolids and we're going to overview industrial pre-treatment so send me questions at any time and i'll go ahead and hand it off to jim okay thanks drew first of all any questions it's been a couple of weeks since we've been together any questions on what we've talked about today dod degradation so in the first two classes we pretty much took care of the the water end of the business today we're going to talk about what we call advanced treatment some people refer to it as tertiary treatment we're going to talk about nutrient removal that additional step that we're being pressed into doing now to remove nitrogen and phosphorus from the discharge water we'll also talked about what happens to all of this material came in as bod and we converted into microorganisms we've taken them out of the process to our secondary clarifier now what happens to them and then we'll just do a quick overview of what happens on the industrial side regulations on industry to essentially protect the potw the treatment facility from problems that might come from metals or organics or other materials not conducive to biological treatments first of all nutrient removal this is something that's been in increasing demand over the past 15 years or more nitrogen and phosphorus what we're referring to we talked about doing future removal i don't know what the plant is but it's a nice looking place increasingly particularly here in new england massachusetts is very hard hit with uh nitrogen removal nitrogen is a big thing it's also part of eutrophication with the phosphorus phosphorus has become even more increasing over the past five to eight years or so again remember what we do here is we're pretty much doing what nature would do nature does nitrification happens in the ground all the time with certain organisms and we're going to use uh in this situation it's largely biological process but in order to get to certain levels in our permits now we do have to resort on some chemical usage to get those numbers down as low as they possibly can again ultimately we're going to discharge waters that don't harm the intended use of the water body so these days the function of most plants certainly in our region is to reduce carbonaceous vod that was the standard set forth between water act that was the base of all of our treatment get rid of the organic matter as much as possible we now have to reduce nitrogenous bod it's another oxygen demand that's placed on the water streams by ammonia and nitrogen compounds we have to remove the nitrogen oven by itself we can remove that as a nitrogen gas again now the the latest thing and the more difficult of the two is phosphorus removal numbers for phosphorus removal are extremely low and we can't achieve them biologically alone we do have to rely on some chemical usage and of course disinfection to break down pathogens remove that from the system you have to refresh your memory this these processes biological nutrient removal is generally done with an activated slice process fixed filled processes like trickling filters and rbcs can remove nitrogen relatively well but you don't have enough control over it and they're certainly not good at phosphorus removal so typically when a plant has to upgrade for phosphorus removal if it's a fixed film process they will add to their process a activated sludge system because that's where we have the ultimate control over what goes on in the process we still have our biological reactor we still have to provide air to these organisms and as you'll see we're going to have to provide more air to keep things going and we have our clarifier bulk of this work can be done in these units we're largely talking the two different types of bacteria that are involved we have heterotrophic bacteria they're the ones that go after carbonaceous bod organic compounds come in they go through a synthesis they consume and break down these organic materials make more organisms off we go they do and this is something that's important to remember when we talk about biological nutrient removal we do need a certain amount of nutrients to keep the organisms in good shape so we don't want to totally remove all the nitrogen and phosphorus at certain locations we have to be careful how we achieve this process again heterotrophs arrows they require free molecular oxygen they need dissolved oxygen in the wastewater that's the whole principle behind pumping a bunch of air into these tanks they could also be anaerobic and thrive in the total absence of dissolved oxygen but the bulk of them are facultative bacteria adjust to the situation we have to rely on these guys to do some of our work for us now autotrophic bacteria are the ones that rely on inorganic carbon carbon dioxide or other sources of oxygen such as nitrates and sulfates it's bound oxygen but they can break that down and get that for their energy needs they're the ones that are going to help us with denitrification and what that term really means a little bit later on they're all functioning pretty much the same way just get different sources of energy and of course we remember that for every hundred pounds of carbon that we're going to deal with we need five pounds of nitrogen one pound of phosphorus it's important to remember particularly we get into phosphorus removal because some processes can remove too much at the wrong place when we talked about dissolved oxygen demand we talked about just plain carbon removal we set a minimum of 0.5 milligrams per liter of dissolved oxygen we want much more now and you'll see why as we look at the nitrification process [Music] so what we need to do all control of the system develop the proper environment and develop the proper population of organisms to achieve these means we're going to have to specifically grow a particular type of organisms for our nitrification process again we're just talking with single-celled bacteria when we look at the heterotrophs on the left-hand column block forming bacteria that's great that's going to help us clean up the water and our secondary clarifier filamentous bacteria are good to a degree depending on the type and the amount that we have again generally we're dealing with aerobic bacteria there may be a situation where we actually need to go anaerobic something that we try to avoid at all costs up to this point you use it and you'll see that in the solids handling you'll also see it in phosphorus removal the bulk of them are facultative bacteria they can move back and forth between systems uh pretty well uh the group on the right hand side these autotrophs are for this little thing the nitrous simonas and the nitrobackers those are the ones that are going to remove the nitrogen for us we'll see how that all works out so again it goes back really gets started nitrification process date back to the 70s but congress came up with a report and found that a lot of the problem with our rivers and streams and lakes was eutrophication too many nutrients going in and causing issues so what happens we put ammonium compounds into the stream there's an oxygen demand depletes the oxygen in the stream aquatic life has difficulty living you have toxicity with nitrates nitrates are a cause of i can't get the turmoil methyl whatever it is blue baby syndrome that gives me your drinking water you have a lot of trouble with some birth defects you have ground water contamination and again eutrophication with nitrogen and phosphorus same stuff that in about two months will be thrown on our lawns so we can cut the grass every saturday you throw that in the river and all you do is promote aquatic vegetation chokes off the stream and you end up with something that looks like this it is the negative side of the whole thing again said in the upper left corner and work your way down through the boxes nitrogen is a nutrient for vegetation so it grows a lot of algae other plants they die they drop to the bottom of the tank they break down and you've probably seen ponds that when you were much younger or nice little ponds that maybe you played with during the summer but now when you drive by them they're just almost a bog because all this vegetation dies off the pond eventually just kind of disappears nitrogen is quite plentiful from plants comes from animal and human waste protein urea ammonium bacterial decomposition can give off nitrogen a lot of sources of nitrogen if you look at the different types we have organic nitrogen both particulate and soluble we have ammonia nitrogen when you add all of those three together it's what we call total caldon nitrogen and then we have the nitrite and the nitrates those don't necessarily exist in nature very much the other three will we have to remove those so nitrification is biological conversion of ammonium compounds into nitrite and then nitrate ion if we do this by adding a lot more oxygen and by developing a specific type of organism yeah this occurs quite readily in nature it happens in the ground very well a lot of nitrifiers out there and this is really what's kind of happening we've got these two particular organisms that we have to develop the nitrosomonas on the left and the nitrobacter on the right if you look at them you can see they're different shapes to them the nitrosomonas are spherical type of an organism and the nitrobacters are more of a rod shaped organism the fact is if you look at them under the microscope and you find them on flocked particles you'll see them existing on the edges of the plot particles they'll generally be on opposite sides of that particle they don't like each other so they stay as far away from each other as possible but we see as we come into the process we've got soluble bod readily available we need a certain amount of alkalinity in the process and our ammonia nitrogen comes in the nitrous amonis bacteria little spherical guys with the addition of a fair amount of oxygen will break down the ammonia compounds into nitrites no2 nitrogen and then the nitrobacters with yet more oxygen will take the nitrites break them down into nitrate nitrogen that's how we break down that ammonia but now we still have a lot of nitrogen in the system we'll have to break that down through denitrification we'll see in a while again they're very common we do not generate any nitrifies they have to come in through infiltration they come in out of the ground that's why we go on an extremely tight collection system leaks here and there isn't a bad thing again they are autotrophs they use carbon dioxide in organic carbon for their cellular synthesis and they're very slow we have to control our process so that we have sufficient time to develop these organisms if you remember the term mcrt mean cell residence time or solids retention time the average time an organism stays in the system for carbon removal three to five days is more than adequate for that nitrifiers in order to develop them first of all they're very temperature dependent if you were trying to start them this time of year you'd have a heck of a time they don't like cold water but in the right circumstances we're looking up 8 10 12 days of an mcrt we have to change our process so we retain these organisms for much longer time in order to develop these two and the slower of the two is actually the nitrobacter which can cause problems if you don't uh keep that in mind the end i just noticed this spherical roughly one micron in size they reproduced by binary fission like most of the organisms out there the nitrobacters are rod shaped and it's a little bit smaller but they reproduce by budding they actually will have a little organism start to branch off from the side of them and then that breaks free and goes up on its own again the nitrous ammonias are fairly quick we can readily break down the ammonium compounds into the nitrites the difficulty is going then from nitrite to nitrate because nitrobacters are slower growing and this term that you see down below is the issue that some facilities will get into if they're not paying attention if they don't need to nitrify and they don't pay attention what they're doing they increase their mcrt they'll get into a situation where they can break the ammonium compounds down into nitrites but they're not sufficiently developed in order to break it down to nitrates and then go on and if you have a lot of nitrites in your system it's called what we call the chlorine sponge it's going to suck the living daylights out of your chlorine demand you're going to be throwing chlorine there all day and never get what you're looking for it's a good indication that you've gone into this nitrite law partial nitrification so in order to nitrify yeah in summer you can probably get away down around five six days generally up around tens where you're safe ph has got to be in the the proper range and the key to it and this uh facilities that get caught in that partial electrification or some part of it is because they don't have sufficient alkalinity you need to have alkalinity in your incoming wastewater so that after the nitrification process you've got 50 milligrams per liter as a residual that's the minimum you want left over the time so a lot of facilities will need to supplement their alkalinity up front with something like sodium hydroxide or mag hydroxide bicarbonate something like that you want to have it in there because it's going to get consumed dissolved oxygen minimum of two product is because we want to make sure we've got sufficient oxygen to get all the way inside the fly and you need all of that extra oxygen as we're going to see as we go through the process again temperature 50 to 30 degrees you're not going to get started below 50 degrees not very easily so come winter time and nitrification and phosphorus removal generally are seasonal limits some just have a clean break that from april 1st to october 30th you have to remove these items down to a much lower level winter time what we call the non-growing period nobody's swimming in the rivers the aquatic vegetations not going to do much at those temperatures so they don't care about it and some like governor blackstone will work down through a couple of brackets they go from april 1st to may 1st and from may 1st to june and then through the summer months it's the lowest that they have once you've got it going you may be able to keep it going through the winter months our process that we had up in nashville we were able to get through winter we just never shut it down because we were afraid we'd never get started again but you got to keep it and you want to look at it from a chemical standpoint this is what's coming in we've got our ammonium ion the ammonium compounds coming in for every gram of ammonium we have to add one and a half grams of oxygen very expensive to add extra oxygen and that's going to form the nitrites and the hydrogen ion is what's consuming that alkalinity you'll actually see a little ph depression as you go through the process because of basically forming some acid then the nitrobacters take the nitrite the no2 again another half gram of oxygen to form the nitrite nitrate and if you look at the oxygen demand for every gram of ammonia nitrogen coming into the process you need four and a half grams of oxygen to complete the reaction and here's where the other expense comes in you need 7.14 grams of alkalinity for every gram of ammonia nitrogen you're going to destroy need some chemical assistance to get this process to go to completion again our microscopic exam is very helpful in looking at the condition of our process the health of the process these two particular stock stillets epistles and vorticella are very common with a good operating nitrification process we don't know if they actually do some of the nitrification or if they just like the conditions under the promote that good nitrification but they're very common to be found when everything is running well so again very temperature dependent below five degrees c nitrification will probably stop it's too cold to develop these guys uh 10 degrees you can get going but it's only at 20 percent of the rate ideally you're up around 25 30 degrees celsius for this to work and pretty much all biological activity is going to stop when you get above 45. again if you look at mcrts in terms of when you're going to start your process if you're at 10 degrees which is 50 degrees that's about what the temperature of the wastewater is right now no probability taking about 30 days mcrt to develop the proper organisms to get this job done certainly gets easier as you get warmer this is something that in the next month facilities that don't have nitrification operating through the winter will start to adjust their process so that they can start developing these organisms it's going to take them 15 to 20 days depending on how their temperatures run through the process to get started in the spring so they'll be starting in march to make sure they're ready for april if the alkalinity is a critical part and something that often gets overlooked to the degree that it needs to be watched again you're going to have a drop in ph over this process as that hydrogen ion gets released from the ammonium compounds and if you don't have enough alkalinity your ph drops below six seven you're gonna start to inhibit your process got to have that in there to make it work right again we need at least 50 milligrams per liter after the process is done at the end of the reactor you should have at least 50 milligrams per liter we can't do that but we need to add some supplemental alkalinity to get the process done or there is a way to get some of that back gonna see in a little bit okay if you look at this plant here we've got a plant 12 10 million gallons a day we've got influent ammonia compounds of 28 milligrams per liter and i need 7.2 essentially pounds of alkalinity for every pound of ammonium coming in so if i do my calculation tells me that i need 16 800 pounds of alkalinity coming into my process in order to overcome what's going to be consumed through the nitrification process when i break that down to a dosage that's 202 milligrams per liter being added to this process things that can be used you could use hydrated lime you could use quickline which would need to be slated soda ash soda ash is not a very strong base it'll add alkalinity but it'll take a fair amount but you've got good control over it sodium hydroxide is very common sodium hydroxide depending on what you're using can be very hot you can watch your phs rise too fast if you're not careful magnesium hydroxide is a good one upper blacks don't just switch from sodium hydroxide to mag hydroxide think about magnesium hydroxide is no matter how much you throw in your ph will never go beyond nine so you don't have to worry about blowing the place up it just won't go into solution then the sodium bicarb is another very safe uh easy one to use that's the cheapest the cheapest is probably quick line but then you have to have the process to slay in it's visible stuff it plugs your lines it's full of grit nasty stuff that's why it's cheap again industry and we'll be talking about industry later on we have pre-treatment programs over there to help keep our processes from being messed up by various chemicals and metals and as you can see particularly on the metals side of things how small a dosage of any of these heavy metals that can start to inhibit the nitrification process you've got platers in town or circuit board manufacturers got to keep a very close eye on those folks so again find the right mcit depending on the temperatures that we're dealing with adjust your wasting rates accordingly keep your dissolved oxygen at a to minimum make sure we get sufficient oxygen out there watch your phs make sure the alkalinity is where it should be and it do a very very good job yes uh just before you get much further i think it's specific to a recent slide but uh what did you mean when you said improve the efficiency of the denitrification process and how is that done uh we're going to get into the united states in just a few minutes so great to see how that works so the for tertiary treatment then if let's say the residence time is 10 days so they have to have 10 million gallons they have a minimum of 100 million gallons of capacity no it's not a hydraulic retention time it's how long you keep the bugs in based on how much you waste so again we bulked up remember bugs don't work very well during the winter time so we tend to build up our mixed liquor solids for the wintertime so we've got enough organisms to work at half speed so now that as we move towards march and april and the water's going to start to warm up they get more active we typically would tend to get rid of a lot of those guys because they're all going to start multiplying and now we'll get out of control but we're going to control our wasting to the point where they're going to slow down they're going to hold more in there for a longer period of time it's all it all comes down to how much you waste so it's not a hydraulic so we don't need 100 million gallons we just hold in the bugs in that much longer so again nitrification can be done very well we can achieve our limits without too much real trouble as long as we keep these important parameters in mind very well we really the only supplement is worrying about alkalinity the only chemical we might need to do the bugs do a great job with that but now i've got a lot of nitrates in the system i've converted the ammonium compounds down into nitrates and i have to deal with my nitrates because they can be problematic so we go through a process called denitrification and what we're going to do you see the little uh cylinder on the right hand side that's what we call acetometer if you remember that from last week we look at settlements to judge how well our clarifiers are going to do but what you if you look at that closely you'll see there's a big blob of brown flock kind of moving towards the upper portion of the cylinder that's the result of denitrification if we don't do something we're going to put this material in a clarifier it's going to be in the fire fire for probably two to three hours it hasn't seen any oxygen for some time since it left the reactor and it's just going to sit there we still have some amount of body we still have a lot of bugs and they want to feed since when we've pretty much lost our dissolved oxygen this is where the autotrophs start working they start looking for another source of oxygen nitrates there's an oxygen there so they're going to go after that o on the nitrate they're going to consume that in the process they release nitrogen as a gas oh nitrogen's gone up in the atmosphere it's 78 nitrogen anyways who's going to notice the problem is we don't want this to happen in a clarifier because that little blob of flock consider that into 124 clarifiers going to be a big mess on top of the surface of that thing and you don't want any flood at the top of that surface you want clean water so we have to take care of this now a lot of permits have total nitrogen limits not just ammonia nitrogen but total nitrogen so we have to get rid of this nitrogen if we do it properly it's cost effective it helps us save some money and will also eliminate the problem of rising solids in the clarifier again we've talked about it aerobic anaerobic we're going to bring in a new term now this bottom uh sentence of anoxic anoxic respiration anoxic respiration is when they go after those bound oxygen molecules an anoxic system basically has no dissolved oxygen i need to typically look at anything less than 0.3 milligrams per liter as an offset it's not anaerobic because we have sulfates or nitrates carbon dioxide oxygen in the water it's just bound up this is what we're going to use this principle to help us again nitrification if you don't plan for it can be a problem i had this issue in my plant i had a horrible time because we weren't set up to really denitrify them again if you look at this diagram here shows the sludge at the bottom of the tank again organisms are looking for oxygen so they can respirate and reproduce they break off the nitrogen and consume the oxygen that leaves and you can see the in picture number two all these little white spots are indicating nitrogen gas levels you get enough nitrogen gas bubbles and both it lifts the sludge and now you've got this number three you see the sludge slowly moving up towards the surface clouding up your effluent putting suspended solids in there it's a problem again if we look at nitrification here in our chart nitrification is going to consume 4.6 milligrams per milligram of oxygen and 7.2 of alkalinity d denitrification done in a certain fashion will allow you to recover essentially half both of those compounds but to do it our denitrification must precede nitrification sounds kind of weird huh we're going to deny it before we knight see how we can do that so for denotification first has to be knights must be nitrifying we have to go into an anoxic condition essentially zero dissolves oxygen we need some carbon there because there's no food for the buds they're not going to eat anything sometimes they actually go endogenous roughly 3 milligrams per milligram of nitrate a little bit left over and you need your bugs now these are not specific bugs they're just your normal facultative organisms so there's no particular uh mcrt associated with denitrifying bacteria it just works well and this is our chemical version of it our nitrate muscle for food and then break down into nitrite and some co2 then the nitrite again some more food the bacterial then form co2 again and give off nitrogen as a gas that's how we actually remove nitrogen from the stream so what we're going to do is we need a selector selector is a portion of a tank where we determine different conditions for it we're going to have an antarctic selector so we want a tank with virtually no free dissolved oxygen and we're going to have some recycle ends and all that and all those have to be subsurface so we don't generate any oxygen being absorbed this is the most efficient way to do it what we've got here is this portion of our reactor at the very uh beginning of our reactor our primary effluent is going to come in our return sludge is going to come into this selector it's going to be an oxide we have no aeration at all we'll have a mixer because we want to keep everything suspended we've still got mixed liquor coming back in we don't settle into the bottom so this is where we're going to denitrify but you say well you have a nitrified yet now we're going to nitrify in this aerobic section nitrification is an aerobic activity as we go through the aerobic section nitrifiers are breaking down the ammonium compounds and forming nitrites so what we're going to do is we've got you see this little box here at the end uh right of the tank the line coming back we've got a pump that's going to recirculate our wastewater from the end of our biological reactor so what we've got here is a nitrite rich stream that's being sent into this anoxic zone and they come in here you've got a lot of food you've got a lot of buds because we've got our return sludge coming in here but they've got no oxygen being added so they go after the nitrites and our nitrogen gas comes out of this tank this recycle flow can run anywhere from one to four times your plant flow but this primary ethylene flow is 10 milligrams uh 10 million gallons a day the recycle stream could be upwards of 40 million gallons a day and this is how we reclaim some oxygen this is how we reclaim some of that alkalinity so again we can get essentially 50 of what is consumed here in the reactor we can get it back in the anoxic zone we don't have to really add so much if any again our conditions in that episode essentially anoxic no aeration that might have cyclic aeration just to keep things in suspension but now they have these new parabolic mixes that are out there to keep things moving we need a carbon source again that situation is primary effluent lots of carbon there could be endogenous they may have to turn on each other as a food source and as we're going to see other processes we're actually going to add carbon generally in the form of methanol or something similar to that we still need mixing in order to keep things in suspension this is uh the mle process modified luzac ethninger one we just looked at basically it's our optic zone there's our aerobic zone one to four times your plant flows being recycled back to the anoxic we can get down to very low numbers quite easily this is an enhanced mle enhanced because what they've done is they've duplicated the anoxic and aerobic section after the original one basically doing it twice in order to make sure they have sufficient carbon source you actually add methanol and there are some proprietary things out there one called microc you might hear of it's basically like an alcohol food source you could use sugar anything the bugs want to eat work well and the reason that this works this will be kind of a polish uh on the anoxic zone for denitrification plus your arrow click here so that you don't deny or anything into your clarifier you can see the numbers get even lower we're six to ten in the uh modified mle and now the enhanced is two to five mld with a denitrification filter this is somewhat common in some plants as we're going to go through our typical anoxic aerobic process denitrifying nitrify and then again as a polish on the end they actually go through a denitrification filter it's basically a fixed film type of an operation we're going to add methanol after our clarifier the organisms live in the sand filter and they'll do the denitrification going through there sequence of batch reactors actually can be modified very well for nitrogen removal just by adjusting their cycles basically you have your recycle here you start up where you just don't aerate at all and that's your inoxic zone you give off all of your nitrites into nitrogen then go through the regular process this particular beast that you're looking at the five stage barden folk all right moved it back from this particular location this is a very complex situation this is actually doing both phosphorus and nitrogen removal this anaerobic zone you see up front is for phosphorus removal and then we go through much like the enhanced mle anoxic oxide and then anoxic and toxic again just to make sure we get our nitrogen numbers down as low as possible i'll explain the whole reason behind this anaerobic zone when we get into the phosphorus removal portion oxidation ditches by adjusting your aerators so that you have an anoxic zone an aerobic zone can work very well in doing it also this is actually north conway they do a very good job and they are particularly tight on their nitrogen levels because they're actually a groundwater discharge if you go through the trees you've got the saco river which is a always preserved river so they can't discharge there they actually pump it into the ground that's why they're really concerned over nitrate so it works very well up there again finally the control is to make sure we have no oxygen in that anoxic zone going back to it as your dissolved oxygen increases the bugs will go after that because it's a lot easier than trying to break it off with the nitrites got to be careful so as we get towards our reactors we tend to taper our aeration down at the back end of the reactor before it discharges so we don't have a lot of excess oxygen that's going to go into the clarifier and then ultimately come back and recycle or it's part of that recycled stream we want to keep that as low as possible so you can see the uh parabolic mixer that they use in these anarchic zones now all right you just drop in any old kind of mixer you can do a lot of relatively low cost adjustments to your existing processes to accommodate nitrification denitrification yes selector zones use plywood you've got some metal corrugated walls here that they can throw up just to help separate those sections from the aerated part of the tank so that's kind of a quickie of the nitrogen process so we remove it any questions we're doing good any questions in the room did that explain the uh improve the denitrification process i feel like i did but uh nick if you want to follow up with another question feel free to send it and we'll address it all right so again those are relatively easy processes to develop and to install in a facility phosphorus removal unfortunately goes a bit beyond that we can do a very good job of biological phosphorus removal but a very good job isn't sufficient anymore phosphorus impacts again more unification we've got chlorophyll what's going in here uh phosphorus and sediment probably for farming communities you get the heavy rains a lot of the fertilizer and stuff washes into the receiving streams and can cause quite an issue point sources ideally and this is where non-point source really affects us a lot we're trying to make up for the non-point sources essentially come from industrial facilities municipal facilities they're not controlled urban non-point sources storm water runoff rain all that good stuff yeah farming golf courses can really uh add a lot to the process so typically our phosphorus coming in is around six to ten milligrams per liter which doesn't sound like an awful lot but still has quite an impact human waste detergent corrosion inhibit our phosphates are used by the uh drinking water people to preserve their pipes so now we've got to deal with it afterwards i also phosphates polyphosphate some organics in there again the limits are going down down and more down all the time history around here the upper black stone uh started to go through an upgrade for their facility based on permit numbers and of course upgrades take a number of years and they didn't complete that before the next permit came out by the time they got the next permit the number was even lower so they had to scramble for even more updates before they finish the first one the other thing you'll see down the bottom corner here is we're also lowering limits on aluminum and iron which is going to cause issues as far as phosphorus removal ideally treat it at the source if you can if you've got an industry that has phosphates in their water we try to work with them they come up with something for a substitute to reduce the amount that comes in again drinking water systems have been adjusted with different chemicals so that that wouldn't be a problem we can do very good job biologically we can get down below one reasonably well and consistently but again now we're looking at 0.5 0.2 0.1 crazy low numbers so we have to go in with chemicals the phosphorus that we're dealing with primarily ortho phosphate and we've got organisms out there that can store this stuff they can take a higher level so we're gonna play with them to make them do that we refer them as polyv bacteria they'll actually suck up excess phosphorus under the right condition again our sludge when we waste it is typically about two percent cost per second we know what's going on what we're going to do is we're going to mess with these organisms so they pull up that excess phosphorus and when we waste them they're actually about six percent that's how we're going to remove this actually goes out with the sludge well as a result of that now that any organisms that we have have extra phosphorus in it if we have issues with our clarifier and our suspended solids and our waste go out now we're going to have elevated phosphorus because now they have triple the amount of phosphorus that we would normally have under those conditions a different thing here so again we've got these organisms that will store this excess stuff and we're going to put them into an anaerobic zone that's why if you go back to that vitamin fold the first thing that you see in the plant is an anaerobic cell what happens is when they go into this anaerobic zone there's no dissolved oxygen there's no nitrites nitrates no sulfates no co2 there isn't an o to be found in that tank so it scares the devil out they just dump phosphorus out of their body whatever analogy you want you just dump it out so if you look at the phosphorus in your wastewater water would actually go up in that anaerobic zone because they're dumping it out of their body so fine we've got a bunch of bugs that have just dumped all their phosphorus out they're stopped for oxygen and they're looking for something and they're good we've got heterotrophic bacteria in there again we've got our biodegradable carbon coming into our primary effluent i'm gonna get these guys to uh when they go in there they dump this stuff out they release phosphorus magnesium potassium forget about that php stuff and then when they go into the oxic zone well actually the next step is an anoxic zone there's oxygen there so this is where they'll start to actually pick this back up very selective they outpace the other ones they start to uptake soluble phosphorus and they're going to start storing it for fear that they're going to be in that situation again and if you look at the water side of things here we come into our tank anaerobic they dump all that phosphorus out so the phosphorus content in the water goes up dramatically and then once they start to see oxygen of any sort they start to re-uptake that phosphorus again and excess so then your phosphorous level of water drops down dramatically back down again they go from originally being two percent phosphorus now they're five and six percent again anaerobic that's a phosphate release once they start to see oxygen of any sort they start updating phosphorus and we put them in the clarifier and we waste them out at three times the normal level that's the whole process behind biological phosphorus removal again we have to build our selectors again we have no aeration we're not going to have any return well let return slides come back in because we need the bugs to do the job we're going to make sure there's no nitrate you see our return stream from the reactor still stays in the anoxic zone which is downstream of the anaerobic no extra oxygen brought in this is where they're going to do their uptake in the aerobic zone okay you go back to the five-stage vitamin fo and this is where upper black stone is starting to head we're going to come into our plant we're doing nitrogen and phosphorus removal through this process we hit the anaerobic zone the organisms dump their phosphorus out nothing's happening as far as nitrogen goes we go into the anoxic zone here's where we've got our nitrate rich recycle comes in here we're going to lose our nitrogen from the anoxic zone and the organisms start to pick up the phosphorus we go through our aerated zone the oxide zone is where we're nitrifying taking the ammonium nitrogen breaking into nitrates to be sent back to the anoxic we're still uptaking phosphorus at this level we're going to go into another anoxic zone we're going to redo the old nitrification denitrification process here with some carbon addition to make sure we have ample supply to keep the bugs fed went to our clarifier pull our sludge out richard phosphorus the nitrogen went away in the two anoxic zones hopefully we're down around 0.5 milligrams per liter of phosphorus that's just biologically and the only compounds or chemicals we had to worry about was making sure we had sufficient alkalinity through the process for the nitrification and we're going to add some carbon of some sort there's various iterations of those processes and sbr again by working your cycles in a certain way you can come in you can be anaerobic for a while phosphorus release then you aerate you've got your uptake kind of a deal sbr up in south berwick maine but again 0.5 is not sufficient for the current limits right now upper blackstone's at point two and they're being pushed towards point one and the other thing that burns them is it's based on a 90-day rolling average what 90-day rolling average means 90 day rolling averages i'm going to collect data for 90 days and i take an average on the 91st day i get a new piece of data i throw out day one and i add day 91 i've still got 90 days of average so you can do very very well up until like day 87 and you have a bad day now you get this big number and it doesn't take much to really skew that number now you're going to live with that bad number for another 89 days you just can't shake it so you you're up against the wall all the time like a system like that so to get below 0.5 on a consistent regular basis we now have to go to chemicals what we're going to do is we're going to form an insoluble precipitate a phosphate floc react the phosphorus with a chemical form a phosphate flux and we have to take that flux out of the process chemicals that are typically used are alum aluminum sulfate sodium aluminate a little more expensive works very well polyaluminum chloride is probably the most common it's relatively easy to work with not horribly expensive and ferric chloride is the one everybody tries to avoid at all costs the problem is aluminum limits aluminum limits in this part of the country pretty much break out back because our background aluminum is so high so you're pretty much eliminated from using them upper blackstone can't go with aluminum they have an aluminum limit so they have to use ferric chloride air chloride is a by-product or used to be a by-product of the steel industry but the steel industry is where now gone to china it's gone overseas so this stuff is not readily available so now they actually have to manufacture this stuff it's relatively inexpensive and pretty consistent now they're manufacturing it in a variety of ways we'll get strange metals and things in there and it's just a miserable stuff to work with very corrosive it's nasty anyways our phosphate block how do we remove solids in our process generally through our clarifier it's a very fine flock and it's hard to settle out so what we'll find in a lot of these processes now is filtration as a tertiary treatment so chemical removal is a lot of different there's single point there's multi-point uh addition uh and here's where some plants uh can kind of get in trouble they will add some before their primary so we'll take it out with our primary settlers but if they add too much they've removed all of the phosphorus from their stream now they don't have what they need to keep the bugs happy you got to be careful as to how much you put in and where you put it okay we're forming this uh metal ion that's going to settle out insoluble metal phosphate could be aluminum phosphate ferrophosphate gonna come out in our sludge again now we're adding a lot of material we're using line for precipitation one and a half times total alkalinity aluminum point eight seven pounds iron one point eight pounds per pound ph's could have to be carefully watched because these materials are all over the place with their phs they work fairly well with simultaneous precipitation we can settle it out with our organisms relatively well but doesn't always quite get you where you need to be particularly with some of the low numbers we have again dosage will depend on how much phosphorus you have coming in iron salts these are all available again the most common is ferric chloride pretty nasty stuff aluminum sulfate these are the preferred methods aluminum is a lot easier to work with again if we have a limit that's going to restrict us multi-point tends to be the best way to go when you look at the process you can do it in one spot but yeah we can add a little bit before our primary clarifier take some out there add some before our secondary and certainly if you're doing filtration you may have to have a third spot if you look at the difference between single point and triple point the actual dosage overall is a whole lot less essentially 50 by taking it out over three phases rather trying to get it all at once requires a lot of jar testing a lot of monitoring on a regular basis as to what's going on again we take it out in our primary can help our suspended solids removal but again you have to be careful about causing phosphorus deficiency we don't want to shorten the bugs on what they're going to get could also consume some of that alkalinity that's coming into the plant because these are acidic streams they're pretty low ph about three five of the ferrochloride coming same thing with the alum so it's going to consume some alkalinity so we may need to supplement that after the process secondary clarifier you get a high level of removal particularly when used with biological phosphorus removal works out pretty well and here's the concern with our effluent with the higher level of phosphorus in your sludge or in your effluent solids if you're at a 0.2 limit let's see you'd have to be down you'd have to have suspended solids uh below three on your f1 screen which is pretty darn tight where's your typical stuff your way out here somewhere before you had to worry about the phosphorus content becomes a concern which is why most of these facilities now go to tertiary filters after the secondary clarifier to make sure we remove any of that phosphate floc that's still in the system didn't want to settle up and we've got all different types of filters we've got deep bed filters we've got automatic back wash we have cloth filters a lot of new stuff coming out all the time now because it's become a very pressing problem automatic sand filters we've got disc filters there's all kinds of variations out there gravity's filters through sander of mixed media like this one shows with anthracite and sand the continuous sand filters one manufacturer that produces these it continuously filters and continuously washes the sand the sand is actually continually flowing through a process so they don't have to take it offline to clean it up that's the flyover for phosphorus uh i do want to go over one thing before we take a break here before we do a solid sandwich just give you some ideas the impact that these low numbers have and and arguing for the wastewater crowd that feels kind of put upon taking the burden of all this stuff but let's see this is from uh upper blackstone in order to achieve the 2008 permit let's see they were converting to a barton flow process for their nitrogen removal they needed additional aeration methanol addition expense there high rate clarification or filtration for the phosphorus numbers but is is the thing that really is an impact in order to do it uh on a yearly basis they'll have to bring in 8 million 100 000 gallons of sodium hydroxide control their alkalinity they'll be consuming 3 million kilowatt hours more electricity annually they'll have uh 20 million 600 000 more cubic feet of natural gas they'll be burning in their incinerator uh 1.8 million gallons of ferric chloride will have to be trucked into that plant you know how many trucks a day that's going to be and they're going to consume 150 000 gallons of methanol and i think i did a quick calculation it probably removes about 100 pounds of phosphorous a day a lot of money per pound when you get down to it but what's that question iron what's that what's [Music] how much water did they treat today uh normal days are around 30 million they have the capacity to go over 100. and the thing is is they fought this whole thing for years between the upper blackstone plant and narragansett bay were eventually discharged 19 impoundments and when they did the river study essentially if they went to zero phosphorus it would probably take 50 years before you see zeroed out at the other end because of all the stuff in the cylinder those are those those are the challenges we have now you have any questions not at the moment everybody out there take a break take us a break then all right we'll be back in a minute 10 minutes yes [Music] all right everybody welcome back we're gonna go ahead and get started with uh solid handling okay so we're done with the water side of things it's all nice and clean and thrown in the river or wherever it's going to go now we have to deal with all the stuff that's been removed from that water that came in the front door and that's where uh solids handling comes into play everything that came in is now being removed as sludge we took out sludge uh the first things we removed were in preliminary treatment we took out screenings we sent that to a landfill we took out grit that went to a landfill now all of the particulate and soluble bod that came in along with any other colloidal material that wouldn't uh be caught in preliminary treatment has to be dealt with it's all been removed through i2 clarifiers primary and secondary now the material that comes out of a primary clarifier is probably about one and a half to two percent solids might be a little more depending on how your process runs material coming out of a secondary clarifier is typically [Music] 0.5.6 solid very dilute streams if we were to go to a landfill with this material we have to have a minimum of 20 solids we got to squeeze a lot of water out of this stuff before we can even get rid of it if we're going to incinerate it we have to squeeze a lot of water out of it because we don't be throwing water on a fire it doesn't work well so this is a very physical type of an operation from here on out it is enhanced with chemical addition though as we're going to see so again we uh in order to deal with solids handling our primary purpose is to reduce the volume of material we're going to dispose of this comes in handy because most small facilities million gallons or less couple million gallons or less will generally go through one step of the process and then ship it to a large facility to be completed because the amount of the equipment the expense of maintaining that equipment just isn't justifiable of a small race that they have so we want to reduce the amount we're going to throw in a truck to ship someplace else save on shipping costs we need to prepare ourselves for disposal landfills again have certain prerequisites for anything that goes in so we have to be able to meet those in terms of solids vector attraction and some other things which are the third items that we're looking at we come into the plant typically if you've been to a facility the headworks building where the water first comes in is one of the smelly parts solids handling is the other one everywhere in between is not bad but these two ends can be kind of rough this particular chart shows pretty much all of the options we have for disposing of solids that come into the treatment plan again screenings and grit we're de-washing washing we're de-watering to a certain degree that can just go off a landfill without too much difficulty scum and solids from primary and secondary and any other tertiary filtration that we may have all have to be dealt with in much more complicated fashions so bring it down into a number of steps facilities may use all of these or some portion of these conditioning as it indicates it's preparation these solids don't de-water quite easily on their own so typically we're going to add some chemical of some sort to facilitate the separation of the solids from the water we call that conditioning thickening is probably the minimum process that any facility will do we're going to take our blend of material that might be one percentage in terms of solids now we want to get it up to something reasonably truckable five six seven percent still pumpable but we want to send to somebody else so it's a lot less water to ship stabilization is a term uh preparation for disposal uh the one that you're probably more familiar with with anaerobic digestion most common method of stabilization that we use and then dewatering is the final step before we go to a landfill or maybe we'll send it to an incinerator or some other material that's where we get up above that 20 percent solid state squeeze the rest of that water off it's too difficult to do in one shot so we go through these various steps again we have incineration there's a possibility for disposes material landfills what we call beneficial reuse composting or land application chemical conditioning it's pre-treating the sludge in order to get it to separate better from the water again these particles that we have tend to have an electric charge to it tends to be a negative charge and what it does is like two magnets of the same polarity if they all have the same charge they don't want to go near each other so they're repelling we have to break that electric bond there stabilize it to some degree so we're going to use some uh chemicals to do that for a long time inorganic salts were the way to go a lot of plants still use these these uh like be familiar because we saw these in the phosphorus removal aluminum sulfate very common ferric chloride calcium hydroxide or lime work very well part of the problem is they're inorganic salts you're adding a fair amount of weight to sludge you've already got to pay to get rid of there are acidic streams and nasty streams quite problematic if you're running an incinerator it could be a an issue with the type of sludge it goes in most commonly now we use organic polyelectrolytes polymers big long chain organic molecules when you put them in you add virtually no weight at all and they really are i've worked with these over a number of years in various applications it's like flipping a light switch night and day difference between when it's there and when it's not you can buy positive charge negative charge you can get no charge you get different charge densities you get different molecular weights a molecular weight start at about a hundred thousand grams per mole run upwards of 10 million huge huge molecules they work really really well you can buy dry material you can buy liquid really good stuff it's expensive though but you don't need much of it use fractional percentages in your solutions dry material can be bought but it needs to be mixed properly these polymers are strange type of chemicals they like water and yet they don't dissolve well you had a handful of a couple of dried powder and you threw some water in there all you'd get is a big jelly mass on the top it wouldn't soak in it wouldn't dissolve anything so you really need the right equipment for it to work it needs to cure for at least an hour or two to really hydrate the molecule problem you can buy it in a concentrated form but you have to make it down you have to dilute it with water before you use it again still need some curing time after that's done or you can buy a straight solution you bring in a 250 gallon tote just hook up your pump and let it run away great stuff and see the type of mixing operations that they have and typically we'll only make up what we call a day tank we only want enough for a couple of three shifts because it degrades with time and temperature a uv light can can hamper it and it's fairly expensive stuff it's you know 15 20 25 a pound so you don't want to be wasting it your typical setup you mix it up and then throw it down to a holding tank before it's used uh here's one particular device for uh mixing dry polymer with the water so you get the proper solutions cell thickening first step that the sludge will encounter after it's left you clarifiers to get into some blending operations but again we're reducing the volume we're getting rid of some of that water if we go from one to two percent up to five to six percent we removed a lot of water cut that volume down to about a third uh various methods gravity thickeners dissolved air flotation centrifuges uh drum thickness there's new stuff coming out all the time again when you look at the difference the amount of water that sludge will bring secondary slides carries a lot of water very light just a bunch of organisms no real mass to it all again by reducing the volume you know we've got a digester it'll work better with less water less water to heat again if i'm setting it somewhere else fewer trucks have to leave the plant every day so gravity thickener gravity thickener is essentially a clarifier dimensions are somewhat different from the ones we've seen previously it's got a very long detention time in it upwards of a couple of days and our sludge will concentrate in the bottom like it does in the other clarifiers but we'll get up to four to nine percent we're going to add some polymer in there to facilitate the settling of this material now the effluent from this thing we're going to be taking water off so the water comes out and has to go back into the process some places generally prior to our primary clarifiers take a look at that effluent stream in terms of solids coming out 350 milligrams blade it's pretty dirty stuff so these streams that we're going to get out of solids handling all come back into the process back towards the front end and can complicate the way things operate depending on when you run it and how well these systems are running too so that's way more solid than you would find in your typical influent wastewater stream that's going to come back to you here's the drawing of one it's like a circular clarifier the dimensions of the diameter in proportion to the depth of the tank are quite different from your typical clarifier which would have a much greater diameter you'll also see a difference in the rake mechanism is considerably different from what you'll find in a typical circular clarifier you see all of these upright rods what we'll call fingers or pickets the reason for these is we've got solids that we've taken out of a clarifier this stuff's not in the clarifier for some amount of time the water is in two to three hours the sludge stays considerably longer all oxygen is pretty much gone at this point we get into that concern about are we going to generate some gases like nitrogen or hydrogen sulfide or methane that's going to pop that sludge well we're sending that material into this thickener now it's going to sit there for upwards of a couple of days no aeration involved there's still some food there's bugs because that's what the sludge is they're gonna break this down and generate hydrogen sulfide methane gas maybe some nitrogen might come out of it if we don't do something to release those gases this stuff's going to pop the idea is to concentrate on the bottom of the tank so as this rake mechanism turns and those pickets work through the sludge blanket they spread the sludge apart so that the gas bubbles can rise to the surface without taking a big blob of sledgehammer we keep things concentrated down at the bottom most of these unlike these here particularly in this part of the country will be covered because again it's sitting there for a couple of days you can imagine how lovely that's going to smell after sitting around for some amount of time high concentration of h2s and methane that's what they look like that one in the upper left there the blue catwalk you can see the picket structure down in the bottom portion of it there to help get those gas bubbles out of the unit they work quite well dissolved air flotation has been a popular method of thickening for a long time again this time we've got a rectangular clarifier but instead of settling we actually want to float this material so i'm going to jump ahead there you go we're going to recycle stream in here we've got a tank we're going to put some air pressure on and these are controlled by here to solids ratio but again we can get up with six seven percent uh solids concentrated in these 50 50 with our preliminary secondary if you look at this tank it's rectangular tank we're going to come in here it works there's no sludge source coming in we're going to add some polymer to this probability it goes into the tank water's going to pass through the idea is we're going to float our sludge to the surface here water's gonna pass under a baffle and then leave as relatively clean sub-meat coming off the bottom and pass away now what makes this system work is let's say for argument i've got 100 gallons a minute sludge source coming in i'm going to leave with 100 gallons a minute of water but what i've got is i've got this recycled stream that we see pulling off from the subnasant line and pumps into this tank i'm going to have 50 to 70 psi of air pressure in the headspace of that tank and what i'm doing is forcing air into solution i'm going to keep that water under pressure until it joins the incoming sledge stream right at the back of the tank once i release the pressure on that line it's just like you taking a bottle of club soda on a summer afternoon after it's been sitting on the picnic table and taking that cap off that's got carbon dioxide under pressure in solution you look at it with the caps on it just looks like plain water same with this once you take that pressure off that stuff can no longer stay in solution atmospheric pressure it's going to come up and properly done it comes out as a zillion tiny microscopic air bubbles attaches to the flock and forces it to rise to the surface and what we do is we keep what we call a blanket of sludge at the top of that tank as the material comes up and accumulate the air bubbles keep trying to release through that sludge flank and compress it and help you water it to some degree so we'll keep four to six inches of sludge at the top you've got a chain and flight scraper that'll start removing on a regular basis and it concentrates up to around five to seven percent solids work quite well and you can see pretty thick uh kind of in the consistency of a chocolate moose you want to think of it in those terms but yeah something you could throw in a tank sent to somebody else let them deal with it works quite well but all that is is you know huge number of organisms all just bound together again the big secrets are working so well is that polymer that we use a gravity belt thicker is a very simplified way to thicken your sledge it's just gravity drainage to a belt filter belt and add some polymer and we control the thickness by our belt speed again four to six percent solids we've got a drawing here and we take our conditioned sludge lay it on top of this belt and the water just drains by gravity you'll see this indication of clouds or plows or chicanes they're just kind of like paddles in there that keeps spreading the sludge from side to side so the water has access to the belt so it can drain better the belt gets washed as it comes back around try to keep it clean it works very well uh this is the one outed uh amherst vass and there's their polymer conditioning tank following the addition smudge comes up and just slides down this ramp onto the belt this white piping on the bottom side as the back wash lines to spray water on to keep the bottle from blinding and all of the filtration is in this sump underneath the unit and that's kind of what it looks like when it's running these you can see these are triangular shaped plows sludge will hit that gets spread apart allows the water access to drain through the belt to get more drainage all the way through nice simple easy to operate type of a system rotary drum thickness i think we might have seen something like this in preliminary treatment just a big rotating drum with a mesh screen on it depending on your porosity depends on how tight your filtration is going to be sludge is pumped into this as this thing rotates sludge keeps moving forward the water passes on through and comes away you see an auger built in there to help keep the solids moving forward to the discharge point merrimack new hampshire got rid of their dissolved air flotation unit and replaced it with two of these a lot less complicated that's a pretty good job of concentrating solids stabilization is something that usually comes in after thickening again what we're going to do is make a stable sludge right to this point it's going to smell kind of badly stabilization will convert into a non-odorous sludge that can stand for some amount of time does a good job of breaking down pathogens reduces insect attraction improves the next phase of the operation again stabilization typical methods are anaerobic digestion aerobic digestion or chemical treatment typically we take a blend from our primary and our secondary put them in these units and we're going to take it from a nasty smelly sticky kind of a substance and make it odor free and easy to dispose of again anaerobic digestion in this part of the country is more common there's not a lot of digesters around particularly here in massachusetts vermont seems to like it quite a bit and basically we are going to intentionally have an anaerobic system we want any air of any sort and it's basically a two-phase operation and overall it takes about a month to complete the whole thing we've got what's called acid formation we're going to take our sludge and this is we call that endogenous phase of their life where we don't have any food so they just turn on each other and themselves as a food source well that's what happens the steel cage match you throw them in a tank with no additional food leave them there for 30 days you see who comes out we're going to reduce the volatile content of this material by about 50 percent it's a great reduction so first process is the organisms got some acid formers in there they're going to break down this material into organic acids fatty acids then we've got another set of organs or organisms called the methane formers that take these fatty acids break them down into methane co2 hydrogen sulfide and water so you have the saprophytic organisms the acid formers convert the volatile organic matter into volatile acids a couple basic ones acetic and propionic acids pretty common and the methane fermenters make methane carbon dioxide and water so again we started out with a bunch of bugs we ended up with a couple of gases and some more water not a bad deal okay we've got a 50 to 60 percent reduction in volatiles it's a very very sensitive operation very good mixing uh the alkalinity to acid ratio is very critical to the system and temperature is very very very tight band and the thing that we have to be concerned with is the methane fermenters of the small people so you can feed this thing fairly quickly and saprophytics will break things down into the volatile acids quite readily but if you can't convert that into methane then you're going to have an issue that ratio is going to get skewed and it's basically the same as you guys having an upset stomach and you just can't throw a couple of tums in there to fix it you've got to correct that ratio so you can do it in cold temperatures 50 to 60 degrees fahrenheit but it takes a long time it's not practical we'd have huge tanks doesn't work the mesophilic bacteria the mid temperature range those are the most common 85 to 100 degrees of range but most of them you'll find by 95 to 97 degrees very much like our stomachs 25 to 30 days this is the most practical method you have to heat it quite so much again very temperature sensitive we don't want this varying one degree one direction or the other from that band good mixing to make sure everybody's getting churned up in there the right ph watching that asset to alkalinity ratio that means we want to watch that in order to determine how fast we want to feed this thing that number gets skewed we got to cut back on our feeding let it mix and let the other guys catch up it can be done at a high temperature some facility i can't remember who it is starting up a thermophilic digester but it's more heating requirement but it is much faster five to 12 days but a lot of other issues going on with it this is a drawing of the old style of two-stage anaerobic digester what you've got is two tanks the first tank is where we're going to form our volatile acids it's a fixed tank it's just a standard tank it's got a kind of a conical bottom to it and it's various means of mixing this material the second tank in this particular drawing is where the gas is going to be generated so in order to accommodate the volume of gas being generated and not have any pressure problems it actually has a floating head to it the weight of that head determines what the pressure is going to be in that tank it's always going to be consistent it just goes up and down depending on the amount of volume of gas you produce you have to worry about the issue being that as the head goes up and down all of the attached piping has joints and stuff like that that'll wear away and leak with dealing with methane gas these things have been known to go boom so you got to be very careful around these things this is the prescribed design these days this is the modern design for anaerobic digester this is up in nashua the green tank egg-shaped tank and you'll find these out on deer island too is the primary digester the pink tank on the left is the second stage that's where the methane is going to be the reason they like this particular design because it is shaped like an egg there are no dead corners or flat spots like we had in the earliest designs you've got very good mixing there are some facilities in fact gorilla farms grout farms does anaerobic digestion to reduce the amount of bod they have before discharging to the treatment plant because what they have is way too high for them to deal with so they got to get it down to about three to four hundred before they can discharge and they'll use this bladder type of digester the bladder just goes up and down with the amount of gas being produced uh they got two facilities that operate both in lynn down in uh franklin also the methane form is a limiting part of the process watch how they're doing if they're too slow then you got to back off the things catch up with it temperature is very very critical but be careful with this and yeah we're generating methane gas so a lot of facilities will take the methane gas generated use it to maintain the temperature in the system it's also being looked at so we haven't heard anything lately that as a source of quote unquote clean energy you can believe it or not using all of the food waste from large industrial discharges restaurants and schools and that sort of stuff going to digest it to generate methane gas to generate heat the thing of it is it's not the cleanest methane gas you ever saw so there's a lot of issues with this is uh the piping at the bottom of the unit up in nashua you can see how that comes down much like an egg to the bottom all of this piping that you see around there is just to help circulate the material to get the mixing that you need to get a really good digestion going on come on here we go and yeah we have to heat it so we're going to run this material through heat exchangers of various sorts this is the one in nashville it's a spiral heat exchanger got hot water in one end and sludge plastic through on the other side maintain the temperatures and it's a very thick material so we're pumping things around with sludge pumps these are piston pumps i'll push that material around can't use that trip his digesters up in vermont the old floating head type and the fixed type over there the old style this is nashville it's again this is now their second stage even though we're producing a gas does not have a floating head floating ahead can be problematic particularly in the climate up here you get snow loads and stuff that just alters everything what we have is very good and reliable pressure control valves on the top to maintain the kind of pressure that we're looking for these type of devices they don't have to have a floating head anymore and nashua at the time was flaring off in most facilities you will find the flaring off their excess methane eat it off but we do get some because again you get eight to twelve cubic foot for every pound of volatile material added and you get 12 to 18 for every pound destroyed you get a fair amount of gas off these things but it's only about 65 to 70 percent methane the rest is nasty stuff some ammonia some hydrogen sulfide some other organic materials in there this material has to be cleaned up before you can use it in a decent burner that's why most people just burn it off let it go and the supernatant we're going to let this stuff settle out let the solids settle out and we're going to draw off the water and again that has to go back into the process and take a look at the solids and that supernatant coming out of there that's pretty thick stuff that's almost as bad as your secondary uh sludge and it can't upset your alkalinity ratios when it comes back in so can be a concern can cause a problem for some of your bnr operations but your digested sludge if you're doing well it's easily dewatered as a mild odor it's black and grainy nice if it's green and gray and stinky then things aren't going well you need to make some adjustments all of deer island sludges uh run through digesters we can do the same thing aerobically it's just a matter of keeping them aerated they still are gonna compete for each other for food you're still gonna get a good volatile reduction but again you're talking large tanks up here from a temperature standpoint it doesn't work very well because once you get down to about 50 degrees it all stops so that means you've got nothing all winter we can do the other portions there and you've got that additional load of aeration again so again something more common down south out where nobody can smell your operations chemical stabilization definitely something you don't see around here anymore there used to be a chlorine stabilization but that was too nasty for everybody to deal with that's gone lime stabilization uh can be done we're basically going to add lime to our sludge anhydrous line and basically it's going to slake in that material it's going to cook up like crazy you've got to get the ph up to about 12 and maintain that for at least a couple hours but it'll get hot as a pistol it'll kill your pathogens again look at how much we're at we're increasing our sledge load by 10 by adding all of this inorganic material so it's nothing you see around here so now we're looking at squeezing the water out so we can finally get rid of this stuff basically it's all a filtration process there are centrifuges that are very common out there also drying beds is something that's uh not common in this region but it's available recessed cavity filters very good method it's just brute force squeezing water out what we've got is a series of filter plates it's called the recess cavities because they're machined so that when they come together there's actually space between the plates inside and we're going to load those up and we're going to get these things up into the upper 20 range in terms of solids quite suitable for a landfill in the drawing of one again these are what the plates look like these two units on the bottom rectangular plates made out of uh polypropylene material like that it's machined so that again when you put them together there's a recessed cavity in between them you have a cloth on each plate that acts as a filter medium there's another small one you see the piping on the the right hand side that end is the fixed end all the piping's attached to that the center pipe is the feed the four corners are for filtrate on the far end there's a ramp this one's a mechanical ram somebody has to crank that thing shut typically you'll have a hydraulic ram in there that runs about six seven thousand pounds to keep it closed keep everything from squeezing out and here's the plates again the filter cloth so when you look at this way we're going to pump our sludge into this this is thick and sludge it's five six seven percent solids uh we're going to use a diaphragm positive displacement pump and fill this up this brown section that you see here that's the cavity we very quickly fill all of these cavities with the slurry and at that point we've got a positive displacement pump it's going to keep pumping so what it does is the pressure from this pump is what this is well it's going to push the water through the filter clot the way these machines are machined that water gets directed down to a hole that's going to bring it out the discharge end and the solids stay inside and it just keeps on pumping until you get to the point where those entire cavities are completely filled with solids you run about 125 130 pounds on the pump pack it in pretty tightly that point should shut down these run automatically they got pressure switches it'll run these things some facilities will then blow air through the process to try to push more water out i relieve pressure on the unit take pressure off the rim and then they'll spread these things apart and i don't think we have a picture yet and there's your filter cape that ideally is what you're going to see come out of there you can take a piece of that filter cake hold it in your hand your hand won't even get damp it's only 25 percent solid great stuff squeeze the heck out of it off to the landfill everybody's happy it's a batch process you run as many cycles as you need to run if you're a large facility and you run 24 hours a day seven days a week because you're taking sludge from all the small guys you're probably going to go with the belt filter press here it's a continuous pressure filtration two belts maybe three belts is different styles out there and we keep increasing the pressure on the two belts as it works through a bunch of serpentine rollers but we've got a polymer conditioning zone condition our sludge with polymer then it goes to a gravity drain zone much like that gravity thickness we saw earlier out from amherst just let the water drain through with the chicanes and all and then it goes between the two belts and it keeps going over a series of rollers and in each set of rollers there's a hydraulic line that comes in to increase the pressure between the rollers and keeps squeezing tighter and tighter as it passes through and again ulti 25 26 28 solids good for a landfill good for an incinerator for composting whatever you want is it working no it's not working it should be running it normally animates so there's your polymer conditioning this top portion is just like a gravity uh belt thickener we've got the plows let the water drain through freely and it goes between the belts again this isn't quite correct because there's two rollers at each of these steps and there's one it's got pressure lines on it keeps squeezing between the two back at the far end here before it discharges it's hard to tell there's two belts a little two belts with solids in there once they separate this material should slide right off from a mechanical standpoint of the base there's a lot of moving parts these are the old units that have been replaced it's been replaced up and upper blackstone and you can see all the rollers and lines hydraulics and everything else there's the gravity drain zone the nice grainy appearance here allowing the water to separate the drain through the belt and then it goes through the your filtrate like the other ones we've seen is not drinking water this is going back into your process you see it down the trough at the bottom you can see the black hoses for the hydraulic lines go into the rollers keeps the pressure on the unit and there's your sludge cake just coming off the end both belts get washed before they come around to receive new sludge and we've got what's called the doctor blade here along the edge to help peel off any uh recalcitrant sludge that wants to stay on the belt shave it right off it drops down this one's going into a screw conveyor it's going off somewhere for whatever purpose uh this can be done in centrifuges too these are very common deer island run centrifuges a lot of them do now we're using a lot of energy you can see at the bottom operates up to 2 000 g's 2 000 times the force of gravity big motors making a lot of noise you can have a batch process with a solid bowl you can have a scroll which is a continuous process it too is a solid wall it's a different design uh this is a cutaway of a solid bowl centrifuge a batch process it's much like the basket inside your washing machine except there's no hole set it's a solid wall this thing's running at about a thousand rpm we're going to feed our thickened sludge into this again with some polymer feed there and let's see boom we look at it this way the yellow represents the solids building up in the bowl the red indicates the liquid portion those things at a thousand rpm when you spray this in the solids being heavier than the liquid get thrown to the wall and get stuck there we keep building up that layer very quickly the annular space fills up with liquid and it overflows the top of the basket and gets caught inside the housing leaves as they what we call a centrate so that's leaving we keep building up this layer of solid still it's just at a point where we don't want the thick solids overflowing the basket you can have a turbidity meter or something like that on the centroid line to say it's starting to get very dirty will stop feeding at this point the machine is going to slow down to about 100 rpm at 100 rpm is where they are it comes with steel you see this big blade here on the side that is going to slowly cut in and it's kind of like peeling an apple as the machine turns it slowly starts peeling that sludge out of it directs it down through holes in the bottom of the basket goes into a conveyor roll off what have you and the way it's gone you need more you run another batch you run as many as you need let's set so it's good for a small facility that doesn't have to run continuously now these uh horizontal scroll centrifuges these are facilities much like deer island who run constantly on the de-watering process what we've got is our drawing of it a solid wall is the housing up here and you see the uh the solid bowl runs and it has a taper on the right-hand side here where it gets narrow angles down that's the solid ball that's going to be spinning about a thousand rpm 1100 inside that we have a second unit and what it has it's called the scroll centerpiece because it has a scroll that's wrapped around it so it's like a screw conveyor inside this spinning bowl now we're going to feed through the center of that inner portion pump it in and at that point we've got openings allow it to spread into the spinning outer bowl same process as before the solids go to the bowl liquids pull towards the center now what we have the liquid discharges on the left hand side of this drawing and the solid comes out on the right hand side after that taper we have orifice on this liquid discharge to determine how deep the pool of water is going to be inside the bowl and what it is the deeper the pool the better the separation between the liquid and the sun the shallower the pool not so much so if you want a really clean liquid you have a deep pool so you've got good separation and clean liquid coming out on the liquid dish the trouble is the deeper the pool if we look at this taper this inner portion this scroll on the inside runs at a slightly different speed different rpm from the outer bowl so it acts like a screw conveyor pushing material towards the solid discharge as the solids go up this taper we call this the beach at some point it comes out of the pool and that allows us to de-water and dry it but the deeper the pool the less beach i have for that to happen so if i want a very clean liquid i'm going to get a wet solid coming off i want a really dry solid i'm going to have some solids in my liquid because the pool is shallower now but i do have some amount of control over the differential speed so i could have a fairly deep pull but if this is moving slowly i can still get a lot of good dewatering for the shorter version that's out of the liquid pool itself so you're kind of working that balance between wet solids and dirty liquid all of these machines are extremely noisy they're good reason that one of my years doesn't work worth a hoot anymore here's the solid bowl you can see the taper at the far end in the upper right hand corner there the housing is open on that big hunks of steel that you don't want getting off on their own that's that inner portion with the scroll on it it worked very well this is something this is not new anymore it's been around for about 20 years this is screw press and uh what we're doing in this one is we've got this cylindrical section with screening on it you can see the top portion here with that cutaway but if you look at the internals we've got a shaft that runs through it and our sludge comes in at the right hand side and a screw conveyor but as it moves towards the discharge the actual shaft of the conveyor itself gets larger and larger so you're reducing the volume as you move towards there and it forces the water out as it pushes it towards the discharge screw press starting to see more of those these days this is probably the newest of the bunch it's the rotary screw press works on pretty much the same principle we're going to have our feed come in here and again it just reduces the volume space inside that unit as it pushes the sludge through and just literally squeezes the water out of it from a drying standpoint drying beds are employed in some places it's it's a great idea if you're in west texas or new mexico or arizona because it's working outside basically you take your thickened sludge and you pump it out into a big cement pan we've got a cement pad it's got a bit of a taper to it a drain pipe at the center on top of that you lay down some gravel and then sand on top of that and pump your sludge out on top of the sand and just let it slowly drain by gravity through the sand some of it again it works great in arid areas because you evaporate a lot of your water too depending on how long you leave it out there depends on what your solids content is when all is said and done you actually add you end up adding material right you're adding the sand and the gravel you have to when you take it out you just do a skim over the sand you don't want to take a lot of it out but again we've got organic matter it's not disinfected we have bugs it's sitting out there just laying around so you can imagine it probably doesn't smell like a floral shower so it's again grayed out in rural communities not too good for uh in town this how it works again you've got a layer of gravel and some sand on top lay it out there let it drain let it drain dry up in the sun that's fine depending on how long you leave it there and get very very dry almost too dry dusty we can run it through mechanical dryers some large municipalities do that before they get rid of their material uh typical thing is just a big rotary dryer rotary kiln our wet material is going to come in here on the left-hand side typically we'll mix it with some dry material to control moisture content and uh on the bottom right here we're going to have our input of drying gases it could be gas fired it could be steam heated air whatever but we have the current current flow wet sludge coming from left to right hot gas going from right to left and as it turns it's it's much like your clothes dryer it's got something in there to help lift the material and have it drop through that hot air stream to help drive off the moisture and run your dryness up to a ridiculous amount probably to start a fire if you're not careful now composting this comes under the category of beneficial reuse we're going to a landfill all we're doing is filling a big hole in the ground someplace and that's getting more and more problematic because we've run out of land for landfills and they get fussy so why just do that composting we're actually going to put it into a beneficial use different ways of doing it static pile windrows and mechanical you stack file in the top portion of that picture and windrows down the bottom is a windrow basically take your dewatered sludge and lay it out in a big windrow out in the field again we've got organisms we've got food some moisture hopefully and this guy's going to go through once or twice a week with this tractor unit to aerate the pile so that the organisms have oxygen to do their job and it really cooks up pretty well this is part of a static pile composting unit this was in bill rick it no longer operates it laid down a layer of wood chips on the bottom then they take a blend of one-third de-watered sludge one-third wood chips one-third fly ash blend it up and then lay it down on top of this the black pipe you see pumps air through the mass provides the air for the organisms and you can see now it's all kind of charred looking from the temperature that it develops you see a little bit of steam vapor rising from it if you look carefully it'll sit there for about four weeks cooking up and the temperatures are monitored and various other aspects are monitored during this whole time it has to meet certain specs at the end of the time they would take it out and run it through the screening unit that green beast in the background to recover the wood chips and this is the compost can be used for [Music] i think they did class a vegetable gardens what have you it's fertilizer we're actually putting it to a beneficial use rather than just filling a hole someplace in western mass or wherever it may be all of the sludge from deer island deer islands dealing with 350 to 400 million gallons on a normal day all of their sludge gets mechanically composted they do it inside like a manufacturing process uh and then the theory is the bulk of that gets shipped out of florida for their orange juice orange groves down there you have juice this morning it's like roslindale more high spark i don't know well that's beneficial reuse now we talk about volume reduction the ultimate volume reduction is incineration this is organic matter it burns so we've got two methods of dealing with that multi-hop furnace fluid incinerator we're going to take our sludge stored in there we're just going to get some basically inner material fly ash multi-house furnace is a big big cylindrical unit with a number of layers inside turn multi-hearth one of the parts we're going to take our wet sledge throw it in at the top and break it down as it goes through this unit these are running 1500 to 1700 degrees the first three hearths give or take are mainly driving off moisture just to a certain point and then it actually comes so it helps burn itself as it goes through the cycle then you have to cool it out before you disconnect again a little bit of fly ash going to landfill no vector concerns no bacterial concerns good to go this is a very simplified version of what it's only five hearths in it wet sludge comes in and got a big center shaft that runs through it with brake arms at every heart to keep moving that material back and forth as it goes through the process this is an upper black stone this is hearth number five that is the sludge burning that's not oil that's not natural gas as the sludge on fire but again now you're not only in the water business now you've got air concerns to be worried about you've got knocks and socks and combustion management and all that fun stuff and particulates this is a wet scrubber to make sure no particular matter is going up the stack you've got order concerns this is uh a screenshot from the incinerator that used to operate fitchburg mass the nine hearth furnace uh you can see a lot of temperature probes it's a lot of stuff and you don't even see a lot of the ancillary equipment that comes after this the gas stream goes to a scrubber and various other things they no longer operate this unit they really didn't maintain it it fell into disrepair and they said the heckler and which was very difficult for a lot of other facilities that used to ship them sludge a fluid bed incinerator is a somewhat simplified version of incineration compared to the multi-heart now i've got a big open tank basically and at the bottom of this i'm going to pump hot gases through the plate at the bottom of it hundreds of holes and i've got a couple of feet of sand on top of it if you look at that sand before it gets its name it looks like a fluid flowing around in that airstream again running at 15 1700 degrees somewhere in that vicinity i basically spray my sludge into this tank at 1500 degrees the water's gone in a heartbeat the organics will burn up anything that hits the 1500 degree sand is going to burn the difference here which makes this even though it looks simpler becomes complicated is on the multi-heart furnace your fly ash comes out the bottom on here all of your fly ash goes out with the airstream so now you have to have some method of separating that you're going to go through cyclones you're going to have a high temperature bag house to remove that material from it and you still have all the other combustion concerns to go with it too there's not a lot of these incinerators here in massachusetts connecticut loves them for some crazy reasons the last place i would expect but so be it but ultimately no matter what we do with these solids that came out of the process it's all regulated by epa under their pot 503 biosolids rule if you're composting it sets all of the conditions for class a class b class c is it good for you know get rid of that open fit mine next door can you use it on ball fields or can i put it on my potatoes all different types of parameters that you have to follow it's very closely regulated these facilities have to have their sludge analyzed on a regular basis in massachusetts it's based on the tonnage that they develop they might be sampling monthly it might be quarterly mine i only have to do once a year which is good because it always scares the dickens out of it you take your sled you send it off to a lab and you get seven pages of material that they're testing for priority pollutants the metals pesticides and all kinds of crazy stuff i can't even pronounce hexamethyl depth if any one of those doesn't meet the specs then you're dealing with hazardous waste and paying tons of money to get rid of it this is why the pre-treatment program is very important to see what those folks from industry are sending you because if they send you something that shows up in your sled you can't get rid of it you gotta chase them down make them pay there we go off to the landfill surface application not a common practice down below the northern border of massachusetts very sophisticated down here if you go up into maine and new hampshire they'll take thicken sludge and just spray it out in the field and plow it in on a regular basis fertilizer looks like they do it with commodore very common practice up north in maine too okay but that too you know has to be controlled by what's in your uh sludge at any point in time so i think okay the the concerns again that's why we have to treat our sludge in certain ways they don't want excess water going to landfill they don't want orders in the vector attraction concern well that's part of the issue that we deal with and get rid of our solids i believe that takes care of that portion question um yeah so i had a question about chlorine chemical stabilization you said it was uh not that common no one really does it anymore could you say more about it why is it the case well think about you're going to take your sludge you're going to react with chlorine now you've the same kind of problem with the lime sludge what are you going to do with a 12 ph sludge why don't you take that stuff the chlorine in addition to just dealing with chlorine very problematic you've got the exposure issues the sludge itself is going to be very acidic when you get done with it the moisture in the sludge and the chlorine are going to form hydrochloric acid and it's just problematic in disposing of it so you almost end up with a hazardous wastage that's been to get rid of um just about um when the epa tested your selection it came back and something was there it sounded like are there avenues to try and find the source of that and maybe pursue oh yeah you have to okay so it's not just here we're gonna do a relatively quick overview of industrial waste treatment dry cleaner i don't know if i already told you the story dry cleaner up in plymouth new hampshire bought the dry cleaning fluid to the process and that made all of their sludge as this waste just by that so yeah and then he was on the whole game and his insurance company were dealing with that material after that point he had a pretty good fine not to mention all the costs that he had involved in it jump right in race through this i think so all right let's give you a little overview as to what happens uh as far as industrial waste treatment goes massachusetts is uh somewhat unique from the other states in the region in that they have industrial waste water certification if you're in industry and you discharge into the collection system you need to be permitted the state by the local facility you need to have certified operators to operate this system and certainly if you're an industry and you're a direct discharger you fall under epa and you've got your own nippy's permit whole other ball of wax but we have to do it because again you go back to these slides for years the rivers were just dumping grounds and you may see that again real soon what else uh and industry just used them as a sewer everything got thrown out there so again the miller river out there there's 1975 that's only four years ago from industry situations like this they're trying to avoid they throw a set of streams down there the pipes would collapse and run away it's just not conducive to good operation thing i found surprising clean water laws actually started back in south carolina of all places back in the 20s and a number of other states had them too but it wasn't because they were concerned about us really it was business was complaining they wanted to use the river water in their processes but it was too dirty that's why they had any kind of clean water loss with a business driven not any environmental issues again this is all the amendments of the federal water pollution control act originated 1972 was the clean water act with 77 87 and 90 these are all largely directed towards uh industry those kind of things so again they have to do it because at a minimum epa requires them to on 77 which don't interfere with the operation don't have material that will pass through and end up in the receiving waters don't mess up the sludge those were the generals and they went specific we didn't want to blow up the sewers like we saw from that lexington issue there in 1980 we don't want anything corrosive that will ruin the collection system piping no ph is less than five nothing that will plug up the lines solid and viscous pollutants choke things up and cause sanitary sewer overflows again nothing that will interfere or pass through no high temperature stuff that will inhibit biological processes again here's the interference from large organic molecules could just pass on through nothing that causes safety problems generate uh dangerous gases what have you in the collection system or in the plant and no midnight haulers nobody dumping it where they're not supposed to go but here's what uh else they came up with they said well they had a apparently engineers were cheap back in those days in the late 70s so they took a bunch of them lost them in their little cubbies and said don't come out until you're done calculating they generated what we call categorical pre-treatment standards where they looked at industries and specific segments of industries and came up with numerical economically and technology achievable limits for these industries we didn't rely on the locals coming up with the numbers that this is what it's going to be and as you can see well partly off the wall here a long list of different industries and if you look at them a lot of them have as many as five different categories that you could fall into my particular operation this one here we pull up organic chemicals plastic from synthetic fibers i'm not sure why but that's what we ended up and i can't remember which one of these numbers we fell under but they lay out all of your limits this is what you have no psalms or buts about it we don't care what the locals say these are the minimums you're going to have it could be concentration based they can be mass based it's very specific the local authorities can be even tougher you can always get tighter than the fed you can never get looser so as you go towards washington the numbers get bigger so they came up this term significant industrial user if you're a significant industrial user that means you are under closer scrutiny than the average industry and to be an siu if you fall into one of those categorical standards then automatically you fall into a significant industrial user category if your flow is greater than twenty five thousand gallons a day oh siu this is greater than five percent of the hydraulic or organic loading on the botw you fall in there or if they just don't like you much they say hey you got a chance to mess these up we're going to put you in this unit local regulations any free treatment any treatment any plant with a greater than five mgd design flow has to have a pre-treatment program it's part of their nifty's permits required and if it's less than five they can make you have one anyway because there's somebody in your system that can really mess up your day and you get to set numerical standards this is uh where is this this is devon's but this is the permit written by the local potw this is not epa this is not the state of massachusetts this is uh yeah it is debits out of debits they wrote this permit for this they say what your level is going to be for the various pollutants how are you going to sample it and how often you're going to see it and if you look down here at the bottom there ph epa says nothing below 5 has nothing on the top end the state says nothing below 5.5 has nothing on the top end but invariably you'll find the locals will have here's what five five to nine five an upper limit onto their ph the fluorite how much they can do in the course of a day all of these other parameters have to be looked at some are in concentration some are in pounds per day 200 pounds a day on nitrogen or phosphorus 40 pounds how often they're going to report when they're going to do it and what the dates are was going to report to all of that good stuff and then the signature line i certify under penalty of law that this document blah blah blah we just got a report from uh jason's here at epa over a fellow down and i think it was new jersey he's going to jail he's got a million dollar fine he just refused to make the changes he was supposed to make people go to jail over this time reduce user fees by reducing your body levels of various other things you might get a lower uh rate on your sewer build than other things and you certainly don't want to be the bad guy in town again we look at some of these categorical electroplating boom is the kind of pollutants that we deal with chemical manufacturing it could be anything paper mills notoriously nutrient deficient talked about nitrogen for our bugs you've got a paper mill in town you may actually have to add nitrogen to your system to make your uh organisms happy dairy processing now in massachusetts well dairy processing is an industry they would be certified under a municipal process because they are doing biological process anaerobic digestion to reduce their vod heat processors all of that stuff circuit board manufacturing that's the live large reason why we have it here in massachusetts back in the 80s there was circuit board manufacturers in everybody's garage jewelry manufacturing pharmaceuticals i'd get you through lunch wouldn't it and these are the right here massachusetts to cover that sort of stuff again as an industry you can be a direct discharger as we were up in nashville we'd have a nifty permit you can be direct discharging to the potw and be an indirect discharger and if everything's fine you have to do anything or in most cases as we do here in massachusetts you're going to have to pre-treat to some degree a minimum of ph control and be an indirect discharger [Music] industrial treatments a lot of different things could be very simple can be extremely complicated it can be physical chemical in massachusetts physical chemical is what we look at on an industrial certification or it could be a biological municipal side again these folks would all be categorized as municipal operators because they're doing biological process all of this physical chemical pretty much the rest of the crowd so they go through preliminary treatment also against preparing for further processing most people just stop at this point we might equalize our streams we've got a lot of different streams coming in you want to design your plants so that you can run it a relatively constant flow constant dealing with constant uh concentrations of pollutants and stuff so you've got varying streams around throw them all into one big tank blend it up so that you're dealing with something pretty steady different ways you can have one tank you could have a side street bring it into this tank let everything blend out you've got one consistent stream coming out over here if you get periodic dumps of very high hydraulic flows or high concentrations kick it off to the side into the equalization tank and then just blend it back in so it's not a big surge of either concentration or flow screening they don't want to treat uh solids anymore than anybody else you have to take it out very similar to what we saw in the municipal side the tangential screen works very well no moving pod sort really vibratory screens pre-fed screen internal fed screen similar devices to what we saw on the other side grid separation very common here we've got uh training for a company that makes abrasives they have to separate all their grit from their waste stream right through cyclones oily waste definitely want to get rid of that we don't want to be sending oil to the potw we've got different types free oils emulsified and water soluble oils we have greases don't get these by floatation or skimming it's very simple to do grease falls into the same range the little skimmer we've got is a plastic tube much like a tigon tubing but has a particular affinity for oil got a little motor device up top and it just keeps this thing rotating through as it rides around on the surface of the tank it picks up the oil right down up through this picture on the right a little wiper blade there that scrapes off the oil it drops down to this little trough and you can collect it in a 50 gallon drum or 250 tote whatever it may be to remove the oil from your system it's an api oil separator for larger systems it's much like a clarifier flow's going to come in and we've got these uh coalescing units in the center to help take all the small globs of oil make larger ones so they float better it works just like a clarifier or we could use a centrifuge oils this is oil and water that is kind of bound together you've got to break that emulsion and freed up the oil steam and some polymers will do that for you once you do that you can treat it like a regular free oil and this is pretty much where most industries in this state will stop ph adjustments just make sure it's between that five five to nine five easiest things kind of feel like ph okay typically we're trying to get between five and twelve and the local permit will dictate what that's going to be you can improve things downstream if we're doing other stuff reduces corrosion utilize acid prevents corrosion optimizes chemical reactions that's very critical in precipitation of metals and hexavalent chrome reduction and destroying cyanide but very simple stuff generally we're using uh sodium hydroxide is probably the most common method of raising a ph in these systems you can find varying concentrations it's easy to work with lime is strong it's full of grit sturdy hydroxide works nicely again you won't go over 9 ph with that material sodium carbonate kind of weak stuff gives you a lot of control we want to bring ph down sulfuric acid is probably the most common i record pretty nasty stuff most people don't want to deal with it you can actually take flue gas and bubbly through a water stream forms carbonic acid and that's very weak acid for adjustment so primarily what we're looking at here is removing metals the biggest concern and we have to get this material out again but it comes from of any number of places plato's chrome plated circuit board manufacturers galvanized fence manufacturers galvanizing fences metal pickling photo processes tanneries various other spots all kinds of sources out there you have to deal with all of these types of things you may have to deal with neutralizing acids we've got hydroxide precipitation of metals copied not so common oxidation of cyanide destruction cyanide vas are common inflating operations cyanide will kill you got to take care of that problem we have to reduce uh hexavalent chrome hexavalent chrome is a carjack so we have to reduce that down to trivalent chrome which is a pretty innocuous chrome exchange may come into place a lot of different operations at the upper levels of this type of operation playing streams we've got concentrated solutions the little bridge solutions we've got chelating agents in there which can inhibit precipitation of metals we deal with precious metals in a different fashion and we've got those other units to deal with a chelating agent is using plating to hold metals into solution longer than they normally would so they don't come out and ruin a plating operation but in order to precipitate that metal later on you have to break that bond otherwise it's still not going to come off that could be a problem they're very common these two items against cyanide and hexavalent chrome nasty materials cyanide or helium and every now and then there's somebody dies because they didn't handle their cyanide properly hexavalent chrome again is the carcinogen problem we have to remove by reducing that to trivalent chrome it's our erin brockovich that's what she was dealing with that whole time out there x chrome different processes but hydroxide precipitation is the most common method of removing metals from a process stream these are solubilities of metals in solution but these are ideal solutions and so we're going to add sodium hydroxide to a solution of whatever these metals are up to a certain ph you get the minimum solubility that we're looking for something that's below our permit level if you know what your permit level is if it's 0.3 then you find out what ph you need to go through and adjust your ph at that point material comes out of solution and we'll go through some other methods to remove it from the stream altogether the trick is if you look at like chromium the only one to really get concerned with n zinc it actually re-solubilizes as the ph goes up so if we've got a couple of metals in there we may not be able to get them all at the same ph we have to remove the chrome first and then go after the nickel as a separate process altogether so get complicated well you find out the best phs and you go after that and you may have to do it in a couple of steps and if you look at your process that's what you'd see as you go from left to right that bluish material is your waste stream before treatment you form your hydroxide now you've got this cloudy water in the second beaker and we add in some polymers we go through coagulation the next step we get some good floc then another polymer for flocculation real heavy plus it's starting to really separate with nice clear supernatant and run it through a filter or clarifier and that beaker on the right is what you should have when all is said and done x chrome again we have to treat that so that uh no longer there hexavalent chrome is the common method in chromic acid so that has to be dealt with and so what we're going to do is we're going to reduce that at a low ph ph becomes a critical part of all this we're going to add some sulfuric acid some sodium bisulfate those are reducing agents we form chromic sulfate you see down here in the bottom that's chromium the plus six plus three four and we got some residual salt and some water we go to the next step how'd that happen all right go back with you okay and then i can take this and use my hydroxide and precipitate out my chrome from that end up with some sodium salt as a solution cyanide again that has to be dealt with carefully if your cyanide bath ever gets acidified then cyanide gas will come out and it's not a good day and i guess basically the gas chamber that you just generated unintentionally so we have to get that out of the water just to make sure we don't have any chance of that getting acidified anywhere that's a two-stage operation we use chlorine for that chlorine form cyanogen chloride as an intermediate at a ph up around 11. and we'll react that with sodium hydroxide to form sodium cyanate a very quick chemical reaction right there and we can take our sodium cyanate and react that with sodium hydroxide and come up with removing our uh just some nitrogen and carbon dioxide is what we end up with as an end result so we start out with a deadly gas and end up with something very innocuous apparently i've lost a slide or two in that whole process jewelry manufacturers we're dealing with expensive metals now gold and silver platinum they don't want to be making this into a hydroxide and throwing it in a landfill so they're going to treat these differently evaporation iron exchange reverse osmosis are one ways to actually retain this material uh there's a gold there's a operation down in attleboro mass called the robin's company they are a gold house they have gold and they make awards for companies you know the 25-year pin the gold pen the plaque on the wall for the good project or what have you and they actually have gold in there it's all you can do to go in and out of that place of course getting on an airplane and what they do is evaporation they'll take all their waste they'll just boil all the water out and they'll take and refine the gold from that slag that they end up with ion exchange can be used because you can buy specific ion resins that will target specific metal items so you can recover your silver and iron exchange res and then you send the resin out to a recovery house they extract the filter and give you the value of it you're not throwing that money away [Music] and once we form those precipitates we have to go through all the various solids removal methods much similar to what we just saw uh typically when we go through uh clarification stuff we'll go through coagulation calculation then liquid separation coagulation we're going back to using those polymers again first step is we'll add something we've gotten away from the inorganic salts to polymers now we'll add this to neutralize those charges and we'll form a flock again we'll jump in here we want to form a flock with coagulation we add the material to very rapid and intense mixing we want all of this material to be exposed to the coagulant and then we're going to send it through our flocculation without a separate coagulant or a flocculate type of material and then a nice gentle mix now we just want these flock particles to bump into each other and form some massive substance what we're doing so this is a nice gentle slow mix we're going to treat it with kid gloves from here on out so we don't break it up again we go through clarifying centrifuges filtration very similar to what we saw before but on a different scale generally large industry will use big clarifiers like we've seen on the municipal side of things this lamella clarifier is more typical of an industry and they come in a variety of sizes this particular unit has everything you need i've got this small tank on the lower right with a mixer on my coagulation phase high intense brief mixing goes into a larger tank with a slow mixer for flocculation and goes directly into my clarifier and these uh you see a bunch of plates inside the clarifier these are called lamellas and they're there to facilitate the separation of the solid and the liquid the idea being that close spacing between these plates so you can separate very quickly as opposed to this block particle trying to flow through four feet of water and try to come up so that facilitates the separation much more common in industry dissolved air floatation very similar to what we just saw a little while ago again look at the process if you start here in the bottom oil water separation then we've got coagulation flocculation then we go in same deal with the recycle stream and the air pressure causing this stuff to float and concentrate centrifuges again batch of continuous belt thickness similar type of gravity filtration is very common in larger types of operation but when you get down to smaller operations this type of stuff little bag filter basically a polypropylene polyethylene type of a bag that sits inside this filter housing you just run yourself through until your pressure is prohibitive shut it down drain it out take this thing put it in the 50 gallon drum it will get chipped outside his waist some have filtered cartridges long cartridges as you see on the right that's a scale that's a 55 gallon trunk scale for this it wouldn't be bigger than that uh no those are generally pretty small you might have some that are two to three feet long but you know once you take the sock out yeah that's pretty small a relatively small operation but you can get down you know half micron level pretty easily pretty tight filtration get a nice clean stream coming out of that this is a plate filter we get into a larger operation now we need more surface area it's just a series of plates inside this housing i'll have a backing screen and then a cloth filter same thing run it until it's loaded up and your pressure is too high then you can break it down and you take this apart and all of the paper circles with their cake take it throw it in a drum and get disposed of and then we get bigger and bigger and bigger as we go it's a small size of recessed cavity filter and then we talk about membrane filtration which is the tightest filtration going to get down to ro this is different from your typical filtration in the typical filtration what we're doing is we're passing material through a media and solids are being retained on that media what we've got in ultra filtration membrane filtration is what we call cross flow filtration if you look at the you've got a series here we've got an equalization tank some pumps we go into a process tank and this process tank keeps recirculating through the ultrafiltration unit on the right hand side it's a pressure driven process and unfortunately folks online won't be able to see this the membrane allows certain materials to pass through it and other things not to the left like membrane my flow runs parallel to the membrane and the pressure allows say the water to pass through the membrane but the oily portion stays on this side and gets concentrated we don't build up a layer of solids like we do in a typical filter just a lot of stuff go through so you keep recirculating this until your the stuff that can't pass through the membrane gets to a certain concentration that you're you're happy with you say okay i'll take that out and then boom i've got to concentrate that i can feel some and you've got nice clean water on the other side it's a whole different type of a filtration deadlift and you can get down to roll which is the tightest filtration going and care require pressures up to about 1200 psi to drive that process granular carbon is employed in industrial treatment granular carbon removes color removes odors picks up organics works very well uh it's like a very small charcoal if you want to look at it if you bought a whole house filter for your water system it's probably got charcoal inside that and the secret to this stuff is the huge amount of surface area that you get with granule carbon one gram a spoonful has basically a quarter acre of surface area and what it does is it traps molecules inside all of these crevices inside that's where all the surface area is they'll burn certain materials at a high temperature then they'll quench it it causes it to fracture that way so that you've got all of these openings in there and you basically use it like a regular filter you just load up a tank pull the granular carbon pass your material through take out color take out odors all sorts of using filtering air streams to be taken out regenerated through something like a multi-house furnace we talked about methods of saving the precious metals evaporation iron exchange got this way you can actually get your money back you know throwing that away is a waste nice simple little iron exchange system get them as big or small as you need air stripping if i have a contaminant in my water stream that i can remove by changing my physical conditions i actually employed this for ammonia removal from our wastewater stream before we get into nitrification basically you've got counter current stream you've got contaminated water comes into the top of the stripper unit inside there you have various types of media rings that sort of stuff just to give a lot of surface area and your airstream goes in the opposite direction and what you do is you change the volatility of this material you take our waste wastewater stream add caustic bring the ph up to 10 and ammonia can't stay in solution anymore so we'd run it through here and the airstream would pick up that ammonia and take it away for processing elsewhere and i'd have a modified stream coming out of the bottom of this change in temperature volatility changes various things if i had a contaminant that i wanted to recover if it was a solvent of some sort or something like that i could take that airstream and then run it through a condenser the hot uh air and stuff goes through hits the cold pipe the solvent would come out of the airstream as a liquid and i can contain that or if it's something that i don't want i just run it through a thermal oxidizer and burn it off goes off the co2 and water it's gone again when all comes down to it this is why there are pre-treatment programs if they mess up your sludge you go after them they're the ones that do it that's why we have the pre-treatment programs in there so that that does not occur but again it varies from state to state how this is handled i ran an industrial waste treatment facility the design rate of 500 000 gallons a day direct discharges to the merrimack river we had you name a chemical we probably had it and there was not a certified operator to be found that's new hampshire go figure down here would be a great four facility for sure all depends on the state and how they do it vermont has their way of doing it maine has kind of a strange little industrial certification i don't know what new york may or may not have but epa still has it out there facility has to keep an eye on their industrial users on a regular basis not a bad job either be treatment boarded that's the quick and dirty and i do mean quick and dirty on industrial treatment any questions last-minute questions from uh folks calling in feel free i'll give you another minute or so but i know you're probably uh ready for lunch so i'll give it a minute and then we'll wrap up there's no questions any questions in the room thanks jim round of applause for our trainer [Applause] thank you jim thanks folks for calling in uh just like last time we'll post this video online so you can check that out and if there's any follow-up questions feel free to reach out to me and i'll make sure to get your questions thanks everybody have a great afternoon thank you folks do you want to feel