Azura’s David Ellis was invited to join Matt Lensink on the CEM Energy Radio Podcast to discuss the science of anaerobic digestion. Watch the podcast below to hear:
– how the bugs (a consortium of anaerobic microorganism) bug (grow and metabolize organics); in an anaerobic digester,
– how to reduce the amount of organic waste being sent to landfill; and
– how waste-to-energy fits into organics diversion programs.
Scroll down to read the full transcript.
Matt Lensink: Welcome to Energy Radio. On this episode, we are going to get, deep into the bug dust, so to speak. And we’re going to talk to somebody who I’ve gotten to know quite well and think highly of, on a bunch of different levels. I think in some ways the highest level as a fellow business owner and, what that means to serve customers and we’re aligned, and we work together a lot on stuff. And we’ve made an exception on this podcast because usually we try to have owners, but we’ve got, I would say a business owner, obviously not a project owner, but I think the next best thing. Dave Ellis is my guest today on the podcast. Dave, welcome.
Dave Ellis: Thank you, Matt. Terrific to be here. Really appreciate the opportunity to speak to you and your listeners.
Matt Lensink: Yeah, no, that’s great. I was trying to remember this morning how you and I have met. Like that, we’ve done a bunch of stuff together. We’ve run into each other all the time, but that part of the story is blank for me. Do you remember how we met?
Dave Ellis: I’m trying to remember that as you bring that up. I think it, I’m assuming it must have been at one of the Canadian Biogas Association conferences. I’m assuming that that must have been it. When I started going there, maybe 2015 time frame? That’s when I started to meet a whole lot of people in, in this space coming from, from my background and more wastewater and that other industry before, bridging into this.
Matt Lensink: Yeah. Okay, cool. And I just, I can’t specifically remember it, but I’m sure if we asked Natalie, she’ll remember.
Dave Ellis: She remembers a lot.
Matt Lensink: She does. Yeah. So. Let’s speaking of your background. Why don’t we start there, kind of give the listeners because as I said to you before, like I think your background is so rich in terms of, kind of like the kids would call you an OG. Is that right Trisha?
Trisha Aldovino: Yes.
Matt Lensink: Yeah, it’s you know, that you have this background whereas folks like me who kind of came out of school and biogas was already kind of becoming cool. You were kind of doing it before it was cool. So, at least that’s my interpretation. Give the listeners your background and how, how you come to this today.
Dave Ellis: You’re very kind. I would say that this is an overnight success that’s been 40 or 50 years in the making really. And to that, I’m just lucky and very grateful. My background is in, let’s say: chemical engineering, classical consulting engineering, drinking water, sewage treatment plant process design. So, making the bugs work, degrading sewage. After a couple of years working in large multinational consulting firms doing that, you know, poop wasn’t really to my taste, if I can use that phrase, but luckily, I was able to pivot into the industrial wastewater side. And the industrial wastewater is primarily anaerobic digestion for high strength waste.
So, my boss at that time, I didn’t know this, but he was involved in some of the first farm digesters in Ontario in like the ‘81, ‘82 time frame back then. So there were six built in Ontario on-farm. Now in those times: oil did not go to 200 a barrel, a lot of painful lessons were learned about H2S and corrosion in engines, feedstock was not that easy to come by, and after a handful of years all of those first digesters were shut down. Farmers knocked them down, they found better things to do with their time. But luckily for me, he already had some background and strength and some awareness in the industry, so working in food industry digesters in the early 90s was how I got introduced to anaerobic digesters.
Matt Lensink: These are like food processing that has a byproduct stream?
Dave Ellis: Correct. So, you know when you boil potatoes? For instance, that kind of white schmutz water you get? Just 2, 000 gallons per minute of that, all day long. And apparently, you’re not allowed to put that in the river, because it will kill the river. So, you have to treat that to meet compliance. And so that treatment is anaerobic digestion, usually, because that’s the most economical. So then, AD was just because it made money. It was an economic driver, not because it was cool, it just made money.
Matt Lensink: And it made money how? Like, it was more than just compliance, already then.
Dave Ellis: Correct. So, it was the cheapest way to achieve compliance over what is happening at a sewage plant, which is all aerobic.
Matt Lensink: Got it. Okay.
Dave Ellis: It uses a lot of equipment and use a lot of energy to put air into the water. An anaerobic system does most of that heavy lifting, degrading say the potato waste anaerobically. Some of the plants would be able to take the biogas that’s produced, and they would put that back into their boilers to displace geologic gas. And again, that was just one-for-one displacement of geologic methane with biological methane. And in doing that it was whatever the price of natural gas was. There was no green credit or anything of that sort at that time. So, it made economic sense in some projects and in some projects, the cost of 800 yards of stainless steel piping was too much, and so they flared it in the early days.
Matt Lensink: But from a treatment compliance perspective, it was, by and large, the cheapest way to go?
Dave Ellis: Absolutely the cheapest. So that is the mainstay in, say, most of the food industry a lot of folks will have anaerobic digestion. Major breweries, vegetable processors, meat processors, anaerobic digestion, you know, very common.
Matt Lensink: And then the liquid byproduct is that is then going into a sewer system?
Dave Ellis: That’s going either into a sewer system, into a city, or it’s going into some sort of polishing, something that looks a little bit more like a conventional sewage treatment plant. And then from there going into a lake or river, some natural discharge environment.
Matt Lensink: Wow. Absolutely. Okay. Yeah.
Dave Ellis: And so those plants, all over the world. So, I was working on digesters in Canada, the United States, managed a big installation digester project in Argentina, in South America. We’re getting projects in, in Europe, all of those things.
Matt Lensink: And you’re doing this from the perspective of, still as a consulting engineer, as a design engineer?
Dave Ellis: Correct. So, so we’re working for the owner. And so, the owner developed, because they were super smart, the owner developed this really great way of putting together hybrid projects. So, we would be involved in say the process design and getting a project to a 20% or 30% design stage. So, we would know exactly how many doors and windows in the buildings, how big the pumps were, all the major process equipment. And then we would go to a local design builder who would have a local PE stamp in some part of the United States, in South America, in France, they would check for, you know, seismic, snow loads, wind loads, local code compliance. And get the thing built.
Matt Lensink: And would you do the technology selection?
Dave Ellis: Yeah, so we would work with the owner very closely on technology selection. So typically, we would work with them. We would do the technology evaluation, whether it’s different styles of pumps, different styles of mixers, different styles of heaters, and eventually triangulate a in on what was going to be the best total cost of ownership for the facility for an owner who wanted to run these things for many decades to come, and would have a fleet of more than 40 facilities worldwide. So, they had some experience, and we had some experience, and then we built plants together, and got some more experience. But then eventually, as we sort of honed in, we knew pretty fast, what it is we wanted in each respective project. And, and the owner liked it because the responsibilities were really crystal clear, right? If the pumps didn’t pump, or the mixers didn’t mix, we knew exactly, okay, it’s this supplier, that supplier. If the tank’s leaked, okay, it’s either the tank supplier or the tank installer. And ultimately, if the bugs didn’t bug, then that was my problem. So that’s kind of how that worked from a process perspective.
Matt Lensink: Okay. So the bulk of your career, kind of after you, after you decide that, you know, municipal waste is not for you, and you get into this industrial space, that’s that’s really the bulk of your career?
Dave Ellis: Yes. Yeah, absolutely. And then when I got out of the multinational consulting engineering firms, which would have been, well just over 12 years ago, and started my own thing, and grew into Azura Associates now.
Matt Lensink: You’ve been doing this for 12 years now?
Dave Ellis: I have. It’s been immensely entertaining. The ups and downs. And I thought well, the bugs are the same everywhere in the world. You know, I don’t have a design team, I’m not going to build a big job myself. You know, doing a 50 or 100 sheet job, might be the end of me at this point. But certainly, I think we have things to say, and ways we can help owners: get projects built, get them built faster, get them up and running sooner, and have a robust business case.
Matt Lensink: And I think that that last part about the robust business case, I think in, in our space, whether it’s, you know, biogas and RNG, whether it’s where we come from before, which was co-gen, I’m curious your thoughts on this, I think owners often fixate on kind of first cost, and even running cost. But the other variable that I think doesn’t get enough kind of focus is, is uptime, right.
Dave Ellis: Yes.
Matt Lensink: And that’s a broad description, and it means something even more specific in what we’re talking about today, but, you know, curious about that piece of, Hey, you can, you can save some money on how you build it, but you got as you mentioned earlier, a 20, 30 year life on this asset, and you’re going to, in my personal view, you’re going to forget about that first cost when you’re griping about low uptime or low output, right? So, I mean, you probably have a much better view of that than I do.
Dave Ellis: One of the things that we do for some owners, is we’re able to tunnel into their SCADA system and we’re able to look at, kind of on a couple of times a week, look at some of the charts, the different things on their engines, or we get the Hydro One reports emailed in. And I was looking at some and we’re looking at facilities that are looking at like 60% of main plate electrical output. And why is that? Is it because we don’t have the feedstock, bugs are unhappy, we got to change the spark plugs on the engines- whether we’re doing that more often than we thought or not. What is the issue? Grid trips, lightning strikes, you name it, the whole myriad of issues with the Ontario fit contracts, right? When a day of production is lost, you ae never getting that back.
Matt Lensink: That’s right.
Dave Ellis: And so, it’s really a lost opportunity. With, I think in our staff, we talk about this and one of our gripes is lost opportunity, right. And unfulfilled potential, just kind of grates on us a little bit. And so we’re seeing these plants and they’re not at name plate, we have lots of talks with owners. In different business cases, some owners they’re comfortable, their core business they are dairy farmers, they have that as their core business and they’re doing other things, right? That is their absolute decision to make. And so, if this is running at 75%, but takes almost no effort, their call. Versus what’s the incremental cost to benefit of doing more and getting more?
Matt Lensink: It’s asymptotic.
Dave Ellis: Very much so.
Matt Lensink: But I think at 75% you still have a lot of upside before you get to the asymptote.
Dave Ellis: Yes. Some of the, the business owners, you know, we’re working with, say in the US for instance, they are interested in being multi-state fleet operators. They have a completely different view from: I’ve got my 200, 300, 500 milking head here in Canada. We’re looking at some, some projects south or very south, like 50,000 – 80, 000 milking head, just staggering projects, right?
Matt Lensink: Yeah.
Dave Ellis: And so, completely different mindset. The multi-state operators, they’re the ones who are looking at it differently. As I said, like this, this hybrid approach. Okay, we can build one, and then the second one will be better, and the third one will be better still. But by the time we get to number four, we should be kind of honed in on: what equipment works well, what works well in our climate, with our kind of feed stock, with our kind of bedding and X, Y, Z, food waste, what suppliers can we count on, who’s got spare parts when something goes sideways, New Year’s Eve, who’s going to help us and who’s going to hang us out to dry. Right?
Matt Lensink: Yeah.
Dave Ellis: And so that’s where they are now, is they’re looking to build a multi-state asset that will, have legs for a lot of years to come. So, they’re looking at it from a completely different perspective, absolutely.
Matt Lensink: We’re recording this on, uh, I think it’s the 4th of September. It’s the second, second day back to school. We talked about, our kids are off to different institutions, but all kind of back to school. Let’s maybe step back and kind of go back to school on the biology, microbiology kind of process piece here. I tried to draw a comparison of power gen and biogas, and there’s a lot of similarities in terms of uptime around, you know, mechanical components, but where they start to really differentiate is in power gen, whether it’s natural gas or even wind and solar, the resource that drives the power gen is relatively predictable, but in our world, and particularly in your world, you have this, microbiological process that is providing the fuel for this, whether it’s RNG or power gen equipment, but you’ve got, you know, a variable that doesn’t exist in, in many other types of projects. So maybe kind of start and just explain to us kind of anaerobic digestion from a very high level, you know, pretend that you’re talking to somebody who doesn’t know it at all. And you talk about it. There’s kind of, different temperature ranges, there’s different steps to it, to the extent that – that without going too deep – and we might, we’re both engineers, we’ll get probably too deep but give us kind of an overview and then we’ll pick away at it just so that everybody understands kind of what we’re talking about when we talk about the bugs or we talk about the biology of the feedstock, all that kind of thing.
Dave Ellis: Sure, thanks. Anaerobic digestion is a natural biological process, it’s been going on in nature for thousands and millions of years. And so, it’s not particularly new or exciting from that perspective. It happens in the bottom of lakes and rivers, in the muck of swamps, when a fish poops in the water and it sinks to the bottom of the lake, it breaks down. There’s no oxygen down at the bottom of the lake, that’s what is called the anaerobic environment, there’s no oxygen. The opposite would be aerobic. The top is aerobic. That’s where the fish like to swim around. Fish are very happy in an aerobic environment. Lots of air in the water for the fish to get the oxygen to breathe. The anaerobic on the bottom, in the mud, that’s where that other process without oxygen, the anaerobic digestion breaks down.
And so that whole process is breaking down in nature, the material without oxygen. And so, this naturally occurring process that happens in the bottom of warm lakes and rivers or very, very slowly in colder lake environments or in the ocean; as scientists and engineers, humanity has figured out how to package this up and intensify it and exploit it to get useful energy out of these things now.
Much the same way that fruit, so fruit can fall off the trees, and those windfalls, they can rot and ferment a little bit, which is naturally occurring yeast, and they can actually produce alcohol.
Matt Lensink: Okay.
Dave Ellis: And so, apples can turn, generates a little bit of apple cider inside an apple, right? And if you ever see some birds walking funny around an apple tree, maybe they have a little bit of alcohol from some of those things. What humanity is taking advantage of with: beer, wine, cider, making yogurt and fermented cheeses, sauerkraut, pickles, all of those natural fermentations that we’ve been using for food processing, also happened in nature for waste disposal. And so we’ve been, you know, exploiting that for waste management now.
Matt Lensink: Got it. Okay.
Dave Ellis: So it is a multi-step process. There’s a lot of different kinds of bacteria or microbes that are involved in this process. At the heart of it, the engineering version of this is: it’s a tank, with a mixer, and a heater.
Matt Lensink: Right.
Dave Ellis: It’s not a rocket ship. In nature, this happens, pretty easily say in the stomach of cattle and livestock. The engineering version, a tank mixer heater, that is really it. Tank is to hold it all together, have some kind of container where we can keep the air out, keep the oxygen out. The mixing, the bacteria, don’t have mouths. So, if I’ve got a steak, right, bacteria can’t take a bite out of that steak. Instead, we have to wait for that steak to slowly dissolve. It takes a long time to dissolve a steak. So, I think, okay, if I don’t have a mouth, how am I going to eat a steak? Well, you could put it in a blender of some kind, make a smoothie, right? So that kind of pre-chews it, now it’s all little tiny bits. And the other little bits of floating sugars and whatnot in it? Well, if you’re bacteria, your only choice is to soak that through your skin, right? You don’t have a mouth, so you have to soak it through your skin. And that’s why we got to get it really, really small, so it can dissolve and soak through the skin or the cell wall of these bacteria to help them break it down. Okay. And as part of their natural respiration process, they release carbon dioxide, methane, hydrogen, right? Other gases. And because we’ve, we’ve put it into a tank we’re able to then harvest that off the top.
Matt Lensink: Yeah. Now my recollection is there’s, isn’t there like four stages, like hydrolysis?
Dave Ellis: Yeah. Depends where you go to school, whether it’s three or four. I follow the American school where we call it four stages. In fact, in our work, we’ve actually re-envisioned this as more like closer to six or seven stages. Because the classical three or four stages, an academic version where you start with, hydrolysis, we call it hydrolysis, where the material starts to dissolve. And then it starts to ferment and starts to form smelly organic acids. If you smell the rotten potato smell under your sink, that’s the smell of organic acids being made. And that happens in hydrolysis. And that happens in fermentation. So it starts to dissolve, and then ferments, starts to get a little bit smelly, so like sauerkraut, pickles, fermented foods, kimchi, that can then become acetic acid, or what we call vinegar. So, we actually make vinegar, so pickling, and then that acetic acid, that vinegar, is ultimately what gets converted into methane.
Matt Lensink: Got it, okay.
Dave Ellis: Different bugs do those different steps and they each like a little bit different environment, and a little bit different temperature, and a little bit different condition for them to work well. In one big tank, they’ll work pretty well together. None of them perfectly, but all of them good enough.
What we’ve done is on top of that, is we said, now, when food waste comes in, it doesn’t start dissolving exactly. Typically, we put it into some kind of a chopper system. Where I live, we have green bin waste, we have a little bucket on the kitchen counter, banana peels, onions, you name it. Stuff goes in. When that goes into a digester system, often there’s a shredding step, a chopping step, some way to just make it physically smaller, where it breaks down. Often there are other steps cleaning steps, where the plastic bags are getting removed from the waste, or heavy bits of grit that can damage equipment: sand, glass, bone chips, little bits of a bottle caps, things like that, can be removed. And then it’s only after that happens that we get into this hydrolysis process where material starts to dissolve. And then ferment. Matt Lensink: Right. And that’s, that’s partly why I asked the question. I mean, I was hoping you’d use the, the term acetogenesis. I’ve been racking my brain trying to remember what the, what the four stages are. And that’s about as far as I got. But anyways, the other reason I asked was, there’s kind of a couple of different schools of thought as to whether you separate those phases physically, isn’t that right?
Dave Ellis: That’s right.
Matt Lensink: Industry’s still talking about that?
Dave Ellis: Yeah. Of the four stages, hydrolysis, acidogenesis, acetogenesis for the acetic acid, and then the actual methane production, methanogenesis process. Of those four steps, the hydrolysis is the slowest. So that is rate limiting. Anything we can do to speed up that hydrolysis process, opens up the pipeline on the whole system. So that’s where folks who are looking at chopping, grinding, shredding at the front end, they’ve got a pretty good chance of some ROI. If you can look at taking your material from say five centimeters or two inch solids down to a quarter inch, it’s easier to handle. Your pumps don’t plug, your heat exchangers don’t plug. But at the same time, there’s more surface area for the material to start to dissolve, for a different bacteria to get at it and to help the material essentially rot inside the tank. And then all the way down to if you’re sub, like one millimeter size of solids or even, you know, two, three millimeters, then you have just a much better chance of a much faster getting to that hydrolysis stage. And then the whole pipeline is faster from there out.
Matt Lensink: So, we’ve got this biological process. We’ve got these bugs without mouths, that we want to keep happy. I mean, I would imagine there are some pretty key things we want to watch out for, either kind of design of a system and then operation. Like what, what are the, if there were five or six hot buttons around process design or process optimization or operation, what are those key areas?
Dave Ellis: I would say temperature is our first one and pretty much always. All the bacteria and every living thing has a temperature range that it likes and is happy at and performs well at. And outside of that range, it can be stressed, it can slow down or become dormant, or actually injured or killed. Whether it’s too hot or too cold, there’s a key temperature range for us. Typically, most digesters operate in what we call a mesophilic temperature, so medium range, which is about 38 degrees Celsius, 95, 98, 100 degrees Fahrenheit, in that range. And I give a range, again, the scientists, you know, differ from the engineers a little bit on this. From an engineering practice, if the temperature is stable it’s best. Rather than going up and going down. Whereas for any one particular kind of bacteria will have its own personal favorite temperature spot, but because we’re dealing with thousands of different ones, we just need the group of them to be happy. And so the group of them likes it to be stable, and whether it’s 38 or 39 degrees Celsius, that’s not a difference that I get too worked up over, as long as the owner can keep it steady.
Matt Lensink: Okay. So stable temperature.
Dave Ellis: Stable temperature is absolutely number one. The other ranges is pH. So pH is usually a dependent variable, so you get the pH you get, depending on what you put into it and how it feeds. We’ll see some farm digesters that will run a pH of say 7.8 to 8.0 range.
Matt Lensink: Which is slightly basic.
Dave Ellis: Slightly Basic. 7. 0 is neutral so 7.6, 7.5, 7.4, lots of digesters operate in that range very, very well. Depending on the natural balance of how fast we’re feeding it, how fast we’re making acid, right? So, remember that vinegar, that acetic acid, so we’re making acid. There’s always some acid in there, and we’re always taking some acid away to make methane out of it. So the balance of the acid that’s in there is we’re making acid, taking acid away, however much acid is there, drives our pH range.
On industrial wastewater, we’ve seen lots of digesters that are pretty happy at a 6.8 range, 6. 7, or even some of them a little bit lower. they naturally operate on a quite a bit more acidic capacity.
Matt Lensink: And does that mean that deep in the hierarchy of those bugs without mouths, they’re different, or are they the same and it’s different feedstock? What makes the difference between, you know, slightly basic versus slightly acidic?
Dave Ellis: Typically, it’ll be the feedstock chemistry. So, something that has more, alkaline material and alkaline reservoir going into the feed. If we’re a food processor where we don’t have a lot of physical chunks of solids going in, we have a lot of water from say washing the floors, washing equipment, there’s not a lot of what we call alkalinity in that water to begin with.
If we’re coming from an agricultural side or a food waste where there may be a fair bit of alkalinity, some calcium, magnesium, all those good minerals that you and I and everybody needs to grow and be healthy. There’s a lot of those minerals in the manure and in the feed.
Matt Lensink: Got it.
Dave Ellis: Those minerals end up in the digester and help keep it nice and neutrally…
Matt Lensink: So, the bacteria has some flexibility. They can live at slightly basic, slightly acidic function of the feedstock.
Dave Ellis: Yeah, exactly. And from those, from the thousands of bacteria that go in, enough of those live at the different pH’s that they’re able to function as an overall system.
Temperature and pH, and like I said, mixing. So just as they don’t have mouths, they don’t have legs either. You know, when you and I, when we get hungry, you know, we know where the buffet is, we get to, we get to walk over there, right? Bacteria can’t do that, so we have to bring the food to them, and at the same time, we have to take the waste away.
Matt Lensink: Right.
Dave Ellis: So having a good mixing environment is always pretty important that way as well.
Also, a balance of feed. When we are looking at a digester, we always start with macronutrients. Things like if you’re thinking about buying fertilizer at the home store to go in the garden. So it’s potassium, nitrogen, phosphorus, right? Those are, those are pretty key macronutrients where a digester might need hundreds of pounds per day of phosphorus to keep all the bacteria going.
Matt Lensink: Okay.
Dave Ellis: There can be minerals as well. Things like iron, or sulfur, or things of that sort that might need tens of pounds, 20, 50 pounds per day, 20 – 30 kilos per day to keep. Again, keep the biology happy and then all the way down to say trace metals. Where same as bacteria, you and I need vitamin B 12.
Matt Lensink: Right.
Dave Ellis: One of the things in vitamin B 12 is cobalt. And cobalt is a key metal that is required to make the enzyme that helps the methane bacteria, or the archaea, help those methane bugs make methane. They need cobalt to do that, and we get cobalt from vitamin B, they can get it from whatever that feed is in that the animals are getting or in the other waste that’s coming in – banana peels from your kitchen.
One of the things we found is nickel is often thought of as a, as a fairly critical trace metal, that a lot of digesters don’t get enough of. And what we find is for the folks who are taking, say food waste from a factory, they almost never have nickel problems. Right? The stainless steel pipes…
Matt Lensink: Of course, right.
Dave Ellis: Yes, right in most food factories in the stainless steel equipment, there’s enough nickel that is shed off those pipes. Whether they have some acidic water and the pipe, you get just enough nickel dissolves in that those facilities a lot of never have trouble with nickel problems – being low in nickel. Whereas some other type of industry might have low nickel and might need to supplement, but that’s, less common. So very industry specific.
Matt Lensink: And so you’re looking, when you talk about kind of the right feed mix, you’re looking at a combination of what are you feeding into the digester to get energy from, and then like most Canadians do in the winter, you’re supplementing vitamin D as an example, right?
Dave Ellis: Sure.
Matt Lensink: Or you as the service provider is suggesting they supplement what they don’t get naturally from the feedstock. Is that kind of how you see it from a design and operation perspective?
Dave Ellis: Typically, yes. The farm digesters, most of them do not require supplementation. The farm digesters that are strictly manure, most do not. The ones who are codigesting with some other off-farm material, depends. And so I would say probably, maybe a quarter of them would benefit from supplementation, but again, most do not. And that’s because there’s enough nutrition in the manure, or in the spilled feed, or the bedding, or whatever, that those nutritional needs are met that way anyway.
Matt Lensink: Got it.
Dave Ellis: If what we’re getting for off-farm food is just sugar, we’re getting spent soda, we’re getting, Coca Cola syrup or whatever from some, some branded syrups and juices and water and spent beer or spilled beer that comes back in the bottom of kegs. There’s really no nutrition in that. It’s just sugar. So, there’s not nitrogen, phosphorus, all of those things. It’s like my mom always said, right? Eventually you got to eat a broccoli now and again, so you get the rest of your, your nutrition covered off. And so, yeah, if a digester is just not feeding manure, but it’s just feeding melted ice cream, it’s absolutely going to run into problems.
Matt Lensink: Got it, okay. And are you looking at this assessment of if and when to supplement is that something that’s done at the beginning? Is that, are you doing that on an ongoing basis? How does that typically happen?
Dave Ellis: Both. So when, when the project developer or the owner is looking at their feedstock blend. We and others, there’s enough experience in the industry, I think they have a pretty good handle on what might be required. But it’s not until the feedstock contracts actually come to fruition and the material really does show up on a truck that you know for sure, what you’re actually going to get and what you’re going to get this month, what you’re going to get next quarter, what you’re going to get after the 4th of July. And the various holiday periods. And it’s only over the course of the first probably two years that you’ll figure out what would be an average. And then to source those, so there’s specialty providers who will source nickel and cobalt and, you know, different things, some folks self manage, they are able to take some samples and send it to the lab, ask how much, whatever nickel, cobalt, zinc is in it. And they can go to the co-op, so they can go to the agricultural feed store. So just as there’s an agricultural pre mix for livestock, you can get mix for your dairy cattle that will have zinc and selenium and XYZ trace metals. You say, great. I want a bag of this, and I’m just going to throw it in my digester instead, right? And, and you can get most things that way.
There are specialty providers that do that. We help some people self manage it, or different things and they can just do it themselves, right? There’s a lot of ways. Just kind of depends on, like a lot of things, if you want to shovel your own driveway or if you want to hire someone else to do it, but again, it’s not a rocket ship.
Matt Lensink: Yeah. Is there a rhythm of taking samples out of the digester and testing that? And maybe kind of changing the supplementation based on that?
Dave Ellis: Yes, with an asterisk.
Matt Lensink: Oh, okay.
Dave Ellis: That’s the financial piece of it. As a pure consultancy, so we’ve done studies for food processors and helping them put together trace metal blends and they can source that from their local animal feed store, right? That’s a fairly expensive piece of science to do. Whereas the same for you and I, we can have customized medicine. We can fine tune, MRIs and help us balance our nutrition perfectly. But the reality is, that might cost five grand, whereas, you know, for $40, you can just take your Flintstone multivitamin once a day and eat all the french fries you want. Don’t worry about it. It gets you enough forgiveness, the low cost catchall. So, there are both schools of thought for sure. And I think it’s really one of scale. Typically cost of the mineral itself is not the expensive piece. The expensive piece is doing the sampling, doing the lab work. Doing the analysis and the calculations. How much do I need? And then I’m going to have to have a staff member who’s going to be measuring out, three and a half teaspoons of this powder four times a week into my thing. So that whole process, right? It takes hours to do it for a little bit of thing; whereas if I have a pre blend, maybe it’s got too much of some things, but it covers all my sins, I’m forgiven, and I just put this in and we can put in the ice cream and the beer and the soda and just make lots of gas. So definitely there’s a few ways to do that.
Matt Lensink: You mentioned scale. Is there, you know, we’ve been talking through these kind of critical success factors. Is there a success factor around kind of the size of the digester?
Dave Ellis: It is, I hate to say it, but I think there is. Because, well, so you know better than me on the, the RNG upgrading and the injection side of that, just the cost we’re talking about of dealing with the gas utility, and the compressor station, and putting it into the grid, right? That’s a fairly expensive undertaking. Like off, off the top of your head, what would you say in terms of like that piece of the puzzle?
Matt Lensink: Yeah, it’s significant. My question more was around like hydraulic retention time? You and I can go across town to the mandarin and gorge out and we’re going to feel it, right? We’re going to eat too much for our metabolism, in terms of you have a finite size digester or maybe you’re in the design phase and you’ve got options, there is a limit to how much you can shove through, I guess is really where I was going.
Dave Ellis: There is, I think there’s some really interesting for me, some scientific publications around this. A very long retention time, has enough what we call internal nutrient cycling. So this bacteria dies, its body breaks down, it releases the nickel back into the fluid and its neighbors get to eat it. And so, if we’re at 75, 80, 90 days retention time, trace metals, pretty much never help, right? Because the biology is in there so long, they live, they die, they break down, their neighbors get to eat them. And there’s enough internal nutrient cycling. It’s where we want to optimize, right? So that’s where if we want to get down to say 30 days, 25, 20, now we’re starting to be performance oriented. If anybody’s got a digester at 75 days, we can probably double your throughput without even trying, right? Like, that’s easy. But at 30 days, depending on how complex your feed is, again, so again just like us, and if you ever look at your own human nutrition, we eat sugar and fast carbs, like sugars and rice and white bread and fast carbs, we’re able to break those down pretty fast. Fats, and meats, and proteins are slower to break down, so when we’re running at, say, 30 days, that’s still a pretty good gong time, 25 days, 20 days, getting down to 15 days, now we’re really starting to shave and to optimize the process. So, we need as much pre-chewing that hydrolysis part, right? We need to physically make the stuff small enough so the bugs can get at it quickly. We need to do whatever we can to improve how it’s working on that front slow hydrolysis process. And then we need to make sure that the bugs are never slowed because they don’t have quite the right nutrition, right? Like I said, you and I do pretty well on cheeseburgers and fries, but we’re not in the Olympics. Sorry, sorry, I’m not in the Olympics anytime soon. Presumably, for that kind of peak athletic output, I’d actually have to pay attention to what I ate.
Matt Lensink: That’s a good comparison. I like that. Okay. And then by contrast, you mentioned industrial digesters. My limited exposure is many of them operate, you’ve been talking about 30, 25, 20 days, many of them operate where they’re measuring retention time in hours.
Dave Ellis: Absolutely.
Matt Lensink: What’s the difference there?
Dave Ellis: This is a really excellent point to clear up. How fast or how slow your material breaks down depends on the material itself in the feedstock, it has nothing to do with how clever your technology provider is, or what the shape of the tank is. It’s 100% based on how complex the chemistry is of the feed.
So, a complex feed that has a lot of cellulosic materials, straw, corn stover, silage, right? Because that material is chemically complex, you would want your 75, 80, 90 days retention time. A sugar factory, that’s mostly just sugar in their wastewater, might be four hours. And that’s because the sugar is super simple as a molecule. It breaks down really, really fast. So four hours. It’s not because the vendor of the four-hour system has any magical powers or secret knowledge. It’s just that they’re dealing with sugar.
And so, the intermediate stuff, so the ice cream manufacturers, you got sugar and fat, okay. They’ve got a certain typical retention time that is typical for that industry. For industries that have, say, higher solids, the solids, again, we’re back to the mouth thing. Because they have solids they are slow for those solids to dissolve. And once they dissolve, then it breaks down pretty quickly.
For example, for meat processing, you can do a little experiment at home tonight, maybe not. Take a steak, put a piece of meat in a glass of water and leave it on the kitchen counter for like two months, three months. And you’re looking at how fast that piece of meat just dissolved in a glass of water. It takes a long, long time. Whereas if you take a chunk of apple, and you throw it into a glass of water, it’ll break down in a couple days, pretty fast. It’s that distinction similar to some soda thrown in a glass of water, it’s already dissolved. And so that’s the one where it can go in hours versus days versus weeks.
Matt Lensink: Okay, kids, that’s your homework for this week. Steak versus apple and a glass of water. Tell mom and Dad we approve that we approved.
Dave Ellis: Let us know how long it takes to break down.
Matt Lensink: Write into the show. Okay. We’ve got these critical success factors around temperature, pH, mixing, we’ve got the diet, and these trace elements and micronutrients, and then we’ve got kind of retention time which is kind of tied into the feedstock. That’s kind of the gold standard and where we want to aim towards.
Dave Ellis: Yes.
Matt Lensink: I would imagine in your illustrious career, you’ve seen some examples of where that has gone sideways to the extent that you’ve shared. Do you have some stories you can share Dave?
Dave Ellis: I do. I’m just going to have to edit this in my brain here for a second.
Matt Lensink: Mark can always edit it.
Dave Ellis: All right. Thank you, Mark. Yeah. Don’t, don’t get me in trouble here. When I got out of the big consulting game, I was trying to figure out how to, how to help these projects survive. Ultimately waste-to-energy is the only carbon negative fuel we have. And so, it’s important for these to survive. And so, one of those early CBA conferences, tremendously grateful for the folks here for putting those on, and into a farmer who had a digester and was making no gas, should I just bulldoze this thing and plant corn? I’ll make more money on it, and this thing’s just a headache. So, hang on, let me come out there and have a look at it, I’ll see what I can do. And so sure enough, I went out, it was cold, it was acidic, the pH had gone down a little bit too low, it was not making any gas. So, don’t worry, I’m sure we can bring this back. And in a couple of months, it was back up to temperature. The pH, was back in spec, it was making gas again. It was making gas so we could run his engine and make some more heat. And so that all worked well. And then over the course of about two years, sort of coaching along the operations and the different feedstocks. Should I take this feed? Should I take this? I got a call – should I take this other nonsense? We were able to coach him through all of that process. So at the end of probably about a two year span, he decided to double down and get another digester. So that was interesting for us from that perspective that he’s thinking of getting rid of them and he ended up getting another, which, amazing. It helps to diversify the farm income, first off. Helps get waste out of landfill, which is kind of one of the key things where we want to be about, and helps the environment in the community. So we love that piece. And so that was, in terms of projects gone wrong or could have gone wrong. I think it was because of being relatively new to the industry, not perhaps understanding those most critical success factors. The temperature got away from a little bit, the gas production dropped a little bit, the engine dropped a little bit, not quite enough heat going into winter. Now we’re at 32 degrees Celsius, not 38. And we start to build up a little bit of acid because we’re not breaking down the acid as fast as we used to be. So, the pH drops, 6.7, 6.6. We’re not making enough gas. Now we’re at like 27 degrees Celsius. And so those things all feed back on each other. Spiral.
In the industrial wastewater world, we call that the digester death spiral. So, it’s a pretty well-known phenomenon that happens when you hit a low enough pH. The anaerobic bacteria, the methane producing bacteria drop off entirely.
Another project, a marquee project I can only speak about kind of obliquely, is that there were some piece about how they were handling the digestate and what they were doing with that. And some of the things that weren’t really appreciated at the early, like the, the FEL-0, the early pre-design stages of what do we do with digestate? If we put into some kind of dewatering machine and we get some solids out and we get some liquid out, what do we do with that? But if our feedstock’s a little bit dry, well, that’s great. I got all this water here, I can just put this back in, in the front of my digester. And I’m sure you’ve seen this too. So, we’re not just bringing back water, right? So that’s where, as far as, say your mechanical designers. If I can, if I can move it with a pump, it’s all water, right? And whereas, you know, the rest was like, well, it’s water, it’s got salt, it’s got ammonia, it’s got you know, X, Y, Z stuff in it. And so that’s where, um, if we bring back a bunch of ammonia, nitrogen, and we mix up with a bunch more digestate, that’s fine. But the next time through, we got double the amount of nitrogen in the water this time. And we’re going to bring that water back around again, and we’re going to put it through a third time. And then eventually we build up so much, could be sodium potassium, so salt, could be ammonia. We build up something that harms the bacteria to the point where they got a real serious problem on their hands.
Matt Lensink: That reminds me of the project we’re kind of developing together right now, where we’ve got, we’ve contemplated ammonia stripping it. That I understand it, for that very reason we don’t, we may have to recycle some stuff where we may. And then we were cognizant of that early and trying to bring that out ahead of time, right?
Dave Ellis: Exactly. That’s the key piece, right? Because we’ve got a pretty good handle or again the scientific community has a pretty good handle on salt. So, a freshwater fish isn’t going to survive in the ocean, an ocean fish isn’t going to survive in a freshwater bathtub. Similarly, how saline the water is matters. So that’s where things like commercial ethanol production, fuel ethanol production, very, very high in salt.
We’ve seen that in general, those industries look like those should be great opportunities, but they’re also very high in salt. So, everyone who’s familiar with digesters knows to watch for salt. And so, it’s not a unsolvable problem, but it is a problem. It is an attention point that you need to consider at your early design stage, as you’re still moving boxes around on the whiteboard. Think about your salt. Think about your ammonia. And if you got those two things cracked here, you’re probably pretty good shape.
Matt Lensink: Got it. Are there any other, we’ve talked about some horror stories, talked about some, kind of the key success factors, are there any other kind of lessons learned that, in your brief career… let’s imagine that somebody is listening to this, who’s maybe in a development role on the early stages, whether they’re an industrial waste producer or somebody in the ag community. Are there some other lessons learned that come to mind for you?
Dave Ellis: The way that we’ve seen projects stalled, and tragically in the last 12 months even we’re seeing projects, major projects being mothballed.
Matt Lensink: Projects that were operating?
Dave Ellis: Yes, really operating, making gas, running, running a foul of a variety of situations. And things like, first of all, feedstock, right? It’s very hard to get a long-term feedstock contract. And so, if you think we’re in the waste business versus the energy business, that’s the first kind of mindset. So, the folks I think who are coming at this from the energy business mindset, I think they might be in for a bit of an awakening as people start to talk about a 20 year waste contract. Like those don’t exist in the waste industry. Right?
Matt Lensink: Right.
Dave Ellis: And so if you want a 20 year contract, because your investors expect a 20 year contract, you’re probably going to get that if you sign up for a really, really sweet deal. If you give them a bargain and then which case, how does your project pencil? So, feedstock and long-term feedstock supply is a real challenge to be reckoned with. Then conversely, digestate, being able to get rid of it on the back end. And so that’s the same thing. All of the farmers I’ve talked to, nobody’s willing to sign a 20-year contract for putting your slop on my land. Because the agricultural community take stewardship to a different level than a lot of people in most industries. If we’re talking to somebody who’s four, or five, or six generations on a particular farm, it’s not my land, it’s not even my land for my kids or my grandkids. It’s family land, it’s a multi generational asset. And I don’t want to be the one who puts chopped up rubber gloves from local factory out there. So that kind of thing where investors from across town or, out of the country, or overseas or wherever, they have a different way of dealing than the local community. Both on feedstock supply, as well as on digestate disposal and land application.
So those are the real key things that the sewage world, I’ll say they conquered the basics of digestion in the seventies and nineteen eighties. Digesting this kind of stuff, that’s the newer bit. How do we deal with feedstock? How do we deal with digestate? Those are the bits that people are learning painful lessons today.
And then the third thing I think is time. The timing to get approvals, to get grid connections, is something that I think early on, some people are unaware of just how long some of these processes can take. On a national scale or a grid scale, RNG today is not that great of a proportion, right? In terms of moving the needle on a national level, it’s not that big. Frankly, it is a critical, important waste management tool. Even where we are in Ontario, the landfills, saw one report, going to be full in 10 years, less than 10 years. And we are still today, we’re trucking waste into the United States. So, if it takes more than 10 years to get a permit for a landfill, and we got less than 10 years left, we are today, already in a pickle.
And so, managing our own materials is something I think we need to take in. Digesters can definitely help with that.
Matt Lensink: Right. They’re not the only solution, but they can be a big part of it.
Dave Ellis: Yeah, absolutely. And help push off the timeline on existing landfill space while we sort out some longer-term solutions.
Matt Lensink: Yeah, I love it. So, as we land the plane here, let’s go closer to home in terms of, 12 years ago, you started on your own, take the leap of faith into being your own boss. But talk to me now about, you know, 12 years later as Azura Associates. What are you guys doing? Who are you? You know that kind of stuff.
Dave Ellis: There are five permanent full-time staff, everyone process engineer, chemical engineer, environmental engineering background. And we have a team of four part time contractors who support us on, on all things. From financing, marketing, bookkeeping, the whole, the whole suite of it. Our plan, I guess, like everyone is global domination, right?
Through the miracle of the internet, we have been just astounded at the opportunities that come in the door. We have investors from South Africa, wanting us to help them look at projects in California, and they end up at our doorstep in Waterloo, in the backwater of Canada. We have investors from Geneva with finance people out of Budapest and in the Middle East tech teams working out of somewhere in Pakistan, I’m not actually sure exactly where they are working, looking at projects in Latin America. The world has shrunk tremendously. We get inquiries from Hong Kong, Southeast Asia, it is just mind-blowing kind of some of the opportunities.
Matt Lensink: And you’re providing advisory consulting services to them as they evaluate project investment decisions? Is that, is that most of your work or how does your work kind of flesh out?
Dave Ellis: That’s a super good question. I have to think about it today. So right now, today we are mostly working with owners who are looking at either just managing their day-to-day operations, or most of them are actually looking at expanding operations.
And we work with developers who are looking at new projects, looking at new feedstock, doing independent risk assessment, analysis, due diligence, before the EPCs or the technology vendors get too close to it. Like a FEL-0, more of a design basis, early stage.
And then once in a while, thankfully not too often, we get involved in some of these projects gone wrong, whether it’s independent review, arm’s length review of something, if, you know, the parties are all speaking to each other, still. Root cause analysis, workshops, those kinds of things where something’s gone wrong and everybody just wants to fix it. Involved with those. And sometimes though, if a ruckus should break out, then it’s okay, we’re going to go to alternate dispute resolution, mediation, arbitration, expert witness kind of stuff, that kind of stuff.
Putting that together. But thankfully not very much of that. Most of the projects should be successful. And, and can be successful. We just got to get them there.
Matt Lensink: Right. It’s almost, I don’t think this is your marketing plan, but it’s almost like, people will hire you at the beginning or at the end. And it’s probably better for everybody if they bring you in at the beginning.
Dave Ellis: The beginning is the best. Like we would like it most at the, at the front end, because certainly having crawled around the bones of enough projects, it’s like, man, all of these lessons, these are easily solvable things. This thing that was 25 million bucks on the backend, this was really a $20,000 problem at the front end. We could have solved this.
Matt Lensink: Once it’s on the whiteboard, it’s cheap and easy to fix.
Dave Ellis: Absolutely. Yeah, absolutely. That’s, that’s the point. But it’s, as you said, though, first cost, versus lifetime cost.
Matt Lensink: There’s always that tension.
Dave Ellis: And so, the owners who are new to it, maybe putting some of their money in there, may reprioritize or proportion their costs differently, maybe than how you and I would. Cause we’re conservative engineers, we want everything to last a million years – okay, so that’s not going to happen. But, where we, as you said, that creative tension, where that lands is, alright, we know that these brands of pumps work for us, and if they don’t work, I can get spare parts in 24 hours. So, the multi-site operators are the ones who are really learning those lessons. And if in this jurisdiction, there’s a lot of plastics because they accept diapers into their green bin program, whereas this other jurisdiction does not, we still get a few diapers, but not very many.
It’s those kinds of things. It’s those real niche lessons that they’re learning still. But yeah, likely much more fun on the front end. Dealing with plant ops and the day-to-day stuff, that’s where some of these lessons come from. Operators are immensely entertaining to work with. They have a very clear speaking way of seeing the world, and they’ll take no nonsense, so we appreciate that very much.
Matt Lensink: For sure. Good. So, if listeners want to get a hold of you, Dave, what’s the best way to do that, is there a website?
Dave Ellis: Yes, it’s azurassociates.com. A Z U R A, another A S S O C I A T E S dot com, Azura Associates. Another time I would make a much shorter URL, domain name, didn’t know that. Anyway, AzuraAssociates.com. There’s a web form there for urgent matters. The web form, actually it comes to my cell phone. So, there’s a pretty good chance.
Matt Lensink: So, I’ll play a prank on you at the end of the weekend.
Dave Ellis: Yep. Urgent, critical matters – the web form does get looked at, pretty much all the time.
Matt Lensink: Awesome. Well, Dave, this has been great. I mean, you and I’ve had the chance to chat on many occasions, but never kind of this deep. And this has been great.
Dave Ellis: Thank you.
Matt Lensink: Appreciate you. I know for us, time is valuable, and I know you’ve got a lot on your plate, so appreciate you coming all the way down here and doing this in person. And as I said to you at the beginning, our goal with the podcast is really to bring kind of stories and experience and knowledge to owners to really make sure their projects are as successful as they can be.
Dave Ellis: Absolutely.
Matt Lensink: I think you’ve brought a lot of that today. So, really appreciate you coming down.
Dave Ellis: Thank you for that. I really appreciate the time as well for yourself, and the whole team here. You guys are doing some pretty cool work, doing some interesting projects and I think there is room in the space for more information and more knowledge to get out to the people. I’m very happy to be part of that.
Matt Lensink: And you guys do great work on, on social, and all the platforms. And I love listening. If we had more time, we’d let you kind of brag on each member of your team. I’ve had a chance to meet all of them and thoroughly impressed. This has been great. And to our listeners, thanks for tuning in another energy radio episode. Really getting into the details and the bug dust, literally. So, until next time, let’s, be safe and make our projects as successful as they can be. Thanks.