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Episode 41 | Are These Tools in Your ToolBox? Bioreactors by Illinois Extension
The Illinois Nutrient Loss Reduction podcast explores efforts to reduce nutrients in Illinois waterways from agricultural runoff to municipal wastewater with host Todd Gleason and producers Rachel Curry, Nicole Haverback and Luke Zwilling with University of Illinois Extension.
Read the blog at extension.illinois.edu/nlr/blog.
Episode 41 | Are These Tools in Your ToolBox? Bioreactors
00:00:06:27 - 00:00:32:24
Todd Gleason
This is the Illinois Nutrient Loss Reduction Strategy podcast, episode 41. Are these tools in your toolbox: bioreactors. I'm Illinois Extension's Todd Gleason. Today we'll talk about bioreactors, how they're constructed, what they cost, and what benefits they have. Doctor Reid Christianson starts us off. He's a research assistant professor of crop sciences here on the Urbana-Champaign campus of the University of Illinois.
00:00:32:26 - 00:00:37:03
Todd Gleason
I asked him what he does and why he does it.
00:00:37:05 - 00:00:56:12
Reid Christianson
And I do water. I am really interested in how, land management impacts water quality. So whether we're tilling no tilling, fertilizer application rates or even moving into to the urban arena and what we're doing on the urban landscape. I'm interested in all of that and how that impacts our water.
00:00:56:14 - 00:01:01:27
Todd Gleason
Very cool. Today, however, we're going to talk about bio reactors. What are those exactly?
00:01:01:27 - 00:01:20:21
Reid Christianson
Well, in the agricultural setting, bioreactors are also known as woodchip bioreactors. And they're really just a, hole in the ground filled with woodchips that receives water from a tile drainage system or a subsurface drainage system from a field. And they are for water quality.
00:01:20:27 - 00:01:23:07
Todd Gleason
What's kind of research is the U of I doing with these?
00:01:23:09 - 00:01:40:02
Reid Christianson
We're doing lots of fun research. I mean, the list is almost endless, but we're looking at different shapes, different sizes. We're looking at, extending the water flow path within a bioreactor by adding baffles. And we're looking at, different types of woodchips. We're looking at compaction of those woodchips.
00:01:40:02 - 00:01:55:16
Reid Christianson
We're looking at all kinds of things, related to configurations of those bioreactors. We're also even looking at the how long those bioreactors are in relation to how wide they are, which is which is a really interesting, piece of research.
00:01:55:18 - 00:02:03:02
Todd Gleason
Well, tell me a little bit more about that. Does it make very much difference in terms of the area that they cover and what they're able to do?
00:02:03:07 - 00:02:26:06
Reid Christianson
Yes, the answer is absolutely yes. There's a balance between, what how much water we can get into a bioreactor and how much, how much or how well, that bioreactor treats the water. So bioreactors are set up to to not treat every drop of water. We're taking what's given to us. And sometimes during the year that’s too much so that water bypasses.
00:02:26:08 - 00:02:46:22
Reid Christianson
And if we make those bioreactors wider, we can treat more of the water. But then typically we don't treat it as well or we don't keep it in the bioreactor as long. So the nitrate, concentrations aren't reduced as much. But yeah, that's a really important I guess research topic for us on the bioreactor front.
00:02:46:27 - 00:02:48:11
Todd Gleason
And if you make it longer?
00:02:48:12 - 00:02:49:22
Reid Christianson
Well we make it longer.
00:02:49:22 - 00:03:10:20
Reid Christianson
The water stays in there for much longer period of time, which is good to to reduce nitrate concentrations. But we just sometimes we can't treat as much water. So more water might bypass the bioreactor. Then that actually get routed into for treatment. So again it's it's kind of a balance. And we're really looking to optimize that balance right now in general.
00:03:10:20 - 00:03:17:15
Todd Gleason
And you discussed this just a little bit. But are these very good at reducing nutrient losses from agricultural fields.
00:03:17:17 - 00:03:40:24
Reid Christianson
They are. And that's where that balance is going to come back into play here on this answer. But if we look at just the bioreactor by itself. So all of the water that gets pushed into a bioreactor, we can have nitrate concentration reductions from anywhere from 40 to 80, maybe even even into 90% of that nitrate, gets reduced sometimes even 100%.
00:03:40:26 - 00:04:05:11
Reid Christianson
But we if we can't treat every drop of water from the field, that means we're bypassing water when we connect those two pipes at the end, after the bioreactor. That's the value that we really care about. And that value, the value downstream of the bioreactor is. And the long term average is about 25% less than the value than the nitrate concentrations upstream of the bioreactor.
00:04:05:13 - 00:04:16:22
Reid Christianson
So very general rule would be a 25% a nitrate nitrogen reduction in from bioreactors. And that's a combined reduction including any water that bypasses.
00:04:16:25 - 00:04:36:17
Todd Gleason
Have you looked to see what difference it makes, if they're used in combination with other conservation practices. And I'll start with some things that are larger rather than smaller, for instance, cover crops or a grassy area, catchment basement of some sort ahead of the bioreactor, or after?
00:04:36:17 - 00:04:38:00
Reid Christianson
You are asking great questions.
00:04:38:06 - 00:05:00:05
Reid Christianson
So that combination of factor, the impact of multiple conservation practices, for a given area is really a big gap in our knowledge right now. We don't know how they react together. We can assume or we can make assumptions. And there are some studies underway trying to to quantify those. But basically the the edge of field practice is like a bioreactor.
00:05:00:08 - 00:05:20:09
Reid Christianson
They take whatever you give them. So if you reduce nitrate leaving your field, the bioreactor is going to have less to treat. But it's probably going to function at about the same efficiency. So if you're giving it half the amount of nitrate it's still going to reduce that by 25%. But we're just starting at a different place.
00:05:20:11 - 00:05:31:24
Reid Christianson
So the those combination practices I think are going to be an up and coming area of study. Across agriculture for many different practices and many different types of landscapes.
00:05:31:26 - 00:05:41:12
Todd Gleason
A couple of things. If farmers are interested in this, should they contact you? How should they do that? What's the typical cost of a bioreactor and what's the construction like?
00:05:41:13 - 00:06:07:12
Reid Christianson
Well, the I think the best place to start, if you wanted to do a bioreactor, would be the USDA Natural Resources Conservation Service or the NRCs. They can do that design for you. And if you're working under, USDA program, then there's even, you know, obviously, money available for for helping to put that in. But typical costs, probably range from, you know, hover around that $10,000 mark.
00:06:07:12 - 00:06:35:08
Reid Christianson
So $10,000 to maybe $15,000, depending on how big of an area you're treating. And a good chunk of that cost comes in the form of the woodchips that you need to purchase to put into it. There's we've done research kind of across the board looking at different types of wood chips, but we really see high quality, large wood chips, you know, in the realm of 2 to 3in in diameter.
00:06:35:11 - 00:07:02:10
Reid Christianson
Those are the best. And especially if those don't have any fine materials, like, you know, any, any type of debris from the process. If that's been filtered out, those wood chips are going to last longer and perform better, but they also cost quite a bit more. So it's again, it comes back to that balance. And depending on when or how long you kind of want that bioreactor to last versus does that upfront cost.
00:07:02:12 - 00:07:05:00
Todd Gleason
How long will the wood chips last in the bioreactor?
00:07:05:05 - 00:07:21:29
Reid Christianson
That's another great question. We're kind of reaching the point now where we have bioreactors that have finally reached the end of their life. And we're starting to replace, wood chips. And I think the initial estimates were, you know, maybe, maybe that ten year mark is a good mark the last about ten years.
00:07:21:29 - 00:07:40:12
Reid Christianson
And then you'll take the wood chips up and put and put new wood chips in and, you know, maybe some of the wood chips, we've seen the poorer quality wood chips maybe lasting seven years and the higher quality wood chips we still haven't replaced after maybe ten years. So, that ten year mark was probably a good estimate from the start.
00:07:40:15 - 00:07:43:10
Reid Christianson
So I'm going to keep with that ten year mark.
00:07:43:12 - 00:07:48:03
Todd Gleason
Are there other things that need to upkeep and what does that entail?
00:07:48:06 - 00:08:00:05
Reid Christianson
Yeah, there's actually very little to do with most of these bioreactors. They are they're an edge of field practice. And and they can be up be set up to like set them and then forget about them.
00:08:00:07 - 00:08:24:10
Reid Christianson
But if there is a management component, it would be to to potentially, relieve or move up or let all the water drain out during the summer months when there isn't much water flowing anyway. And then that'll just basically dry that, that bioreactor out and, but those woodchips dry out a little bit. But it also help with, with sulfur reduction.
00:08:24:12 - 00:08:53:17
Reid Christianson
That's one of the kind of the them one of the drawbacks of a bioreactor is if they stay saturated and there's no water moving through, if there's stagnant water, then you can start to get rid of all the nitrate and you start to reduce sulfur sulfate. So, then you get this little, funny sulfur smell coming from, so that's why we typically put in a drawdown plate or a little upside down V at the very bottom of those bioreactors to help them drain out over the long term.
00:08:53:20 - 00:09:02:27
Reid Christianson
But if they don't, if you don't have one of those, you'd pull that, for the plate out. So you could drawdown or dry that bioreactor out when it's when it's kind of dry during the end of the summer.
00:09:02:29 - 00:09:08:20
Todd Gleason
Any advice for farmers or landowners that are interested in installing one of these?
00:09:08:22 - 00:09:21:11
Reid Christianson
Do a little bit of research, but I think reaching out to NRCs would be the first step and the best step, they can not only get you up to speed on what a bioreactor is, they can help you with the design.
00:09:21:15 - 00:09:30:25
Reid Christianson
They probably even help you select a location on the farm, because obviously you need to tap into a subsurface tile drainage system to put one of these in.
00:09:30:27 - 00:09:50:26
Todd Gleason
That was Reid Christianson. He's a research assistant professor in crop sciences at the University of Illinois. He works with Bryan Maxwell, who's a postdoc in the Department of Crop Sciences, also at the U of M, I asked Bryan to tell me a little bit about himself, and we moved to Bryan because he's done some of this installation work.
00:09:50:29 - 00:10:34:21
Bryan Maxwell
Yeah. So, my name is Bryan Maxwell. I'm originally from North Carolina. That's where I grew up and where I went to graduate school at North Carolina State University in Raleigh. I did my PhD in conservation practices, specifically woodchip bioreactors, which is what brought me up here for about a year after grad school. I was working in Spain at a research university over there, also doing work with which is bioreactors and, that kind of indirectly brought me to U of I in Champaign-Urbana, where I'm working as a postdoc in the crop sciences department here with, Doctor Laura Christianson and the group, it's a, Illinois drainage
00:10:34:21 - 00:10:44:00
Bryan Maxwell
research outreach program. So we do a lot of, research and extension work with just various conservation practices.
00:10:44:02 - 00:10:51:23
Todd Gleason
It sounds as if you have a great deal of experience. I would suspect, maybe even in installing a bioreactor.
00:10:51:23 - 00:11:04:01
Bryan Maxwell
Yeah, I have more, more recently. Yeah. So that so that was kind of the, first experience I had recently on the, farm up in, Hillsdale, Illinois.
00:11:04:03 - 00:11:16:05
Bryan Maxwell
That was the first bioreactor I got put in charge of doing the design for, and. Yeah, so I got to kind of oversee that construction and see how they get put in. So it's a pretty cool experience being involved with that.
00:11:16:12 - 00:11:19:13
Todd Gleason
What, are the site requirements for a bioreactor?
00:11:19:15 - 00:11:21:26
Bryan Maxwell
So there's a couple different site requirements.
00:11:21:26 - 00:11:44:04
Bryan Maxwell
They're not the site requirements, you know, aren't as maybe stringent as, you know, some of these other practices have kind of soil type and land slope. Requirements. But you know, you do want to have one of the requirements is that my reactors really are intended to treat, subsurface drains that are catching a lot of surface runoff.
00:11:44:07 - 00:12:09:08
Bryan Maxwell
A lot of times that surface runoff can have a lot of erosion from soil in it. And that stuff can kind of clog the bioreactor pretty quickly. You would probably one if you're thinking about putting in a woodchip bioreactor, you'd probably want some space on your land, or you can set aside enough room for it. These things are usually about 10 to 15ft wide and maybe 40 to 50ft long.
00:12:09:08 - 00:12:39:23
Bryan Maxwell
So you'd want to be able to set aside that much space for one where you're not going to be growing crops or driving around any heavy equipment. Because you're really not supposed to drive over the tops, bioreactors. With that, you'll end up kind of compacting the bed. And you also are kind of generally going to want to know where your tidal drain system is at, where it's laid out, because the these bioreactors tie in to that existing tidal drain system.
00:12:39:26 - 00:12:57:06
Bryan Maxwell
Sometimes we have farmers who aren't totally aware of where that power drain system is because it was put in so long ago. And, so we have an idea of where that those lines are, can help tie that bioreactor in during the construction process.
00:12:57:13 - 00:13:03:27
Todd Gleason
After a landowner decides to install a bioreactor, what's the typical timeline for it to be designed and built?
00:13:04:00 - 00:13:31:05
Bryan Maxwell
So that's a good question that that's something we're trying to figure out ourselves. Just from having more conversations with farmers who are put them in, typically if you're putting one in and you're not working through the university or some other, programs or a different grant program to, get this installed, you might be going through the NRCs Cost Share program, which is what a lot of private farmers do.
00:13:31:07 - 00:13:58:21
Bryan Maxwell
And from what I've heard from various people I've had conversations with, is that normally takes about a year. To put that in because there's a, there's a bunch of different steps in it. You know, the first step is contacting your, local NRCs or soil Water Conservation District office and having a rep come out to your farm and see if it's suitable place for putting it in a bioreactor.
00:13:58:21 - 00:14:33:04
Bryan Maxwell
So they might take some survey, do some surveys of elevations, look at your title maps and see if a biomarker is a good fit. And if it is, then NRCS will actually do the design for it. And then they’ll do that for free. So though that that process might take, depending on the work. And after that, you know, they'll come back to you with the designs and then it's up to you to kind of find a contractor, find the contractor who's available and, and can do that work.
00:14:33:07 - 00:14:46:18
Bryan Maxwell
Kind of working out, timeline that meets both your schedule with the contractor to come out and put it in. And, you know, from what I've gathered, that whole process and we've taken close to about a year.
00:14:46:20 - 00:14:57:15
Todd Gleason
You mentioned that, in the research you've been doing, you were charged with installing the bioreactor near Hillsdale, which is in Rock Island County, Illinois.
00:14:57:17 - 00:14:59:28
Todd Gleason
This one's not typical, I take it.
00:15:00:02 - 00:15:20:01
Bryan Maxwell
That was not typical. There's a couple of interesting things we did with it. So because this one wasn't not was not the design bioreactor, we had a little bit more flexibility with the design, to do a lot of conventional design NRCS bioreactors tend to be long and narrow.
00:15:20:04 - 00:15:42:13
Bryan Maxwell
And a lot of that is for good reason to get together, appropriate hydraulic residence time in a bioreactor. And that determines how much nitrate removal you get. But this is kind of a different interesting site. It's a pretty large site and part of the drainage area, I think. I think it drained about, 30 acres.
00:15:42:15 - 00:16:04:19
Bryan Maxwell
Part of that, drainage area included some runoff from an interstate on the north end of the, drainage area. So we expected that, water coming in would be pretty flashy with some of that, right off on the highway. So we wanted to do is, have a more of a wider design, than a longer one with wider bioreactors.
00:16:04:19 - 00:16:46:07
Bryan Maxwell
You, are able to catch more of your peak flow because it's a it's a wider cross-sectional area coming into the, a wider pipe, being able to pass more water, so that that wider bioreactor, it should be able to catch more of that water coming in. It was also the looking down on it. It would be a trapezoidal shape for the bio reactor, which is pretty, not typical, but one of the reasons we did that was in that plot that that farmer had, that kind of parcel was a wedge shaped, and he was actually still looking to, put some crops down in that field.
00:16:46:10 - 00:17:04:20
Bryan Maxwell
So we wanted to push the bioreactor as far to the south end of that parcel as we could. So that was why the bioreactor also kind of ended up being wedge shaped. Move that, as much out of his way, as possible. So it'll be interesting that we're going to be doing some monitoring on it as it goes on.
00:17:04:20 - 00:17:21:24
Bryan Maxwell
We're going to be monitoring how much water is capturing and how much of the tidal flow is actually capturing. And then, looking at how much nitrate it's actually removing. So we'll be able to look at how this kind of, unconventional design, how well that's working out there.
00:17:21:26 - 00:17:27:23
Todd Gleason
Any advice for producers or landowners that are interested in installing a bioreactor on their property?
00:17:27:25 - 00:17:56:11
Bryan Maxwell
Yeah, you should definitely. If you are concerned about not knowing enough about one. Reach out to a local extension office or soil water conservation district, NRCs office for talking to them. These people are more than happy to come out and help you, learn more about it, how it works, and whether or not, it be a good fit for your property.
00:17:56:13 - 00:18:18:24
Bryan Maxwell
And just, you know, being upfront about what a woodchip bioreactor might mean for your farm. You know, it is a it is a upfront cost for putting it and then, and as far as conservation practice, you know, it's not like in-field management practices where there might be some return on it. This is kind of an upfront cost.
00:18:18:27 - 00:18:39:28
Bryan Maxwell
But one of the good things that edge of field conservation practices is that once you put it in, it's really doing its job, year in and year out without you need to do more or spend more time and energy on it. It's going to be removing nitrate for the next 8 to 10 years. That's about the lifespan of the bioreactor.
00:18:40:00 - 00:18:55:24
Bryan Maxwell
So once it gets to them, it's really doing its job of reducing nitrogen coming off the farm versus, maybe the infield drainage. Good practice like nitrogen management or cover crops where you might be you might need to be doing something year in, year out.
00:18:55:26 - 00:19:03:17
Todd Gleason
That was Bryan Maxwell. He's a PhD student at the University of Illinois. Another site he is talking about belongs to farmer Drew Hohenboken,
00:19:03:17 - 00:19:13:20
Todd Gleason
Who is in Rock Island County, Illinois. I called him and asked him to tell me a little bit about himself, his operation, and then about this bioreactor.
00:19:13:23 - 00:19:27:29
Drew Hohenboken
I am a fifth generation farmer and I farm in, Rock island County, which is in northwest Illinois, the northern end of the county. We're split in half, so to speak, with Quad Cities in the middle.
00:19:28:01 - 00:19:41:05
Drew Hohenboken
We are on the, we're only a mile away from the Rock River, so it's so we've got a lot of bottom ground, corn and soybeans. That's basically everything about.
00:19:41:11 - 00:19:43:28
Todd Gleason
What conservation practices do you currently use?
00:19:44:00 - 00:19:58:16
Drew Hohenboken
Well, I use no till I have some waterways. I use filter strips, wetlands. I also have some, CRP with, 24 acres of trees.
00:19:58:18 - 00:20:08:22
Drew Hohenboken
I have a windbreak that I was planted in when I was 12 years old. I planted it for, for a 4H project, and it's 50 years ago, so.
00:20:08:25 - 00:20:17:22
Todd Gleason
That must be so very gratifying. Why is it, by the way, that you're interested in this case in a bioreactor?
00:20:17:22 - 00:20:31:14
Drew Hohenboken
It's important to have water. Good water quality. It's important for, for every aspect of life, like, farming for, health, public health.
00:20:31:16 - 00:20:45:05
Drew Hohenboken
Because, water is essential to people live. And also it's one of the elements that keeps this country and keeps us going. Good water quality.
00:20:45:07 - 00:20:49:05
Todd Gleason
Why did you choose the specific site for the bioreactor?
00:20:49:08 - 00:20:59:17
Drew Hohenboken
It. Well, it's, close to the waterway, and we have a tile line in the waterway. So they're using, the tile line for the reactor.
00:20:59:20 - 00:21:18:08
Drew Hohenboken
It's by the waterway, which drains, probably 30 acres, but it it starts right next to the Interstate 88. So we're taking all the water off the interstate. They have the, the ditches aligned in a way that it comes down the waterway.
00:21:18:10 - 00:21:21:11
Todd Gleason
Did you use cost share to put the bioreactor in?
00:21:21:12 - 00:21:26:23
Drew Hohenboken
Yes, yes, I did with, cost share with the University of Illinois.
00:21:26:27 - 00:21:29:14
Todd Gleason
What were your costs like in percentage or otherwise?
00:21:29:16 - 00:21:31:13
Drew Hohenboken
Minimal. How's that sound? Minimal.
00:21:31:13 - 00:21:45:25
Todd Gleason
Sounds perfectly fine. Any advice, for producers who are interested in installing this or, or other kinds of conservation? Hard conservation practices?
00:21:45:25 - 00:21:54:26
Drew Hohenboken
Test your nitrate levels first to see if you, if, it's practical, if it's useful for you.
00:21:54:29 - 00:22:19:08
Todd Gleason
Well, that's good advice from Drew Hohenboken. He's a farmer from Rock Island County, Illinois. You've been listening, of course, to the Illinois Nutrient Loss Reduction podcast. This is episode 41. Are these tools in your toolbox: Bioreactors? The program was produced in conjunction with Illinois Extension Watershed Outreach Associates Jennifer Jones and Rachel Curry. I'm Illinois Extension's Todd Gleason.