Talkin' Crap

The Hidden Hazard: Hydrogen Sulfide Safety During Manure Agitation and Pumping

• Dan Andersen • Season 1 • Episode 10

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In this episode of Talkin' Crap, Dan Andersen and Brett Ramirez discuss the risks associated with hydrogen sulfide (H2S) during manure agitation and pumping. They highlight the importance of proper ventilation to prevent H2S exposure, which can be fatal to humans and animals. Find the show notes here. 

Iowa State University Extension and Outreach has developed several publications addressing hydrogen sulfide safety, which are linked below.

Unknown:

Music.

Dan Andersen:

Hello, and welcome to Talkin' Crap, a podcast by Iowa State University Extension and Outreach. This institution is an equal opportunity provider. For the full non discrimination statement or accommodation inquiries, go to www.extension.iastate.edu/diversity/ext. In this podcast, we discuss insights into the science, technology, and best practices surrounding manure management. Our objectives are to build awareness about the challenges farmers and the broader agricultural industry face around manure and to demonstrate solutions in areas of innovation. Hello and welcome to Talkin' Crap. I'm your host, Dan Anderson, Associate Professor and extension specialist in the ag and biosystems engineering department at Iowa State University. And today, we're going to be talking about hydrogen sulfide risk during manure agitation and pumping. This issue is particularly important because there's a risk of both personal health and death as well as risk to animals. So today joining me, I have Brett Ramirez, associate professor in the ag and biosystems engineering department. I'll let you tell tell us a little bit more about yourself.

Brett Ramirez:

Hi, Dan. It's , I appreciate being here, and thanks for having me on today. So my name is Brett. I specialize in ventilation for livestock and poultry facilities, mainly swine and layers. And I'm excited to dive

Dan Andersen:

Perfect. And I'm excited to have a ventilation more into this topic. specialist, because while I like the manure side of it, a lot of this comes down to ventilation. So one of the things I wanted to talk about to get us started was why hydrogen sulfide risks are maybe a little bit more critical to be engaged with now, as opposed to years in the past. What do you think? What Why do we see more animal death from hydrogen sulfide today than past years?

Brett Ramirez:

I think there's a combination of different factors, from ranging from management to what we're feeding pigs, and I think also driving that too is maybe a little bit of sometimes some complacency. You know, with anything related to safety, you can't just do it once. It's a all time thing, and you always gotta be on the ball and paying attention to what those risks are and making sure that you're going through what may be somewhat procedural, time consuming, labor intensive, but those procedures are really necessary to keep people and pigs safe.

Dan Andersen:

Absolutely, I couldn't agree with that more. It is about building a culture of safety. One of the things you mentioned was changes in diets, and certainly we feed more byproducts. Oftentimes, those tend to have a little bit higher concentrations of sulfur in them, and that results in a little more sulfur in the manure. As a manure guy, one of the things I often think about is bigger equipment these days we we just get barns emptied faster than we used to, and that means we need better agitation. We knock that manure around a little bit harder than the hydrogen sulfide tends to come off when when we beat it around and try and move it around quickly. So those all play into it. One of the things I wanted to talk to you about is, I know I push all the time that we should go later into the fall with our application, just so that we can be better stewards of the nitrogen in our manure. But one of the things we run into there is, sort of, how do we manage ventilation and conserving some heat in the barn? Could you give us a couple comments about that?

Brett Ramirez:

Yeah, just in general, when we're, you know, ventilation during pump out and agitation is very different than just our normal day to day ventilation. But I think always just important, as we get into fall, it's going to be the times when we start reducing ventilation rate. And we reduce ventilation rate, you know, primarily just because the outdoor temperature is lower, but then also, you know, we would like to conserve heat, so the most critical thing is really winterizing that barn. You know, getting it tight. I can't stress enough the importance of having a tight barn. That's really the key to minimum ventilation success is having a nice, tight, leak free barn. Then the other important factors are making sure we are controller settings right. There's a lot of opportunity on making sure we get the right minimum speed on our minvent fans, getting the right heater offsets and differentials, getting correct motor curve programmed. All those are going to lead to a nice, energy efficient winter.

Dan Andersen:

Perfect. And you mentioned that we needed a tight barn, especially on those minimum ventilation conditions. Why is it more important there?

Brett Ramirez:

Because air is going to take the path of least resistance into the barn. And so when air has opportunity to choose between our ceiling inlet or through holes, cracks, gaps, you know, whatever, you name it, it's going to prefer to go, take the short circuit and sneak in through those cracks. And the problem with the cracks is, you know, some people say, if my whole barn leaks, doesn't that ventilate evenly? Well, yes, but we really want to bring the air in through the planned spot so we can mix it and get it evenly distributed throughout the barn.

Dan Andersen:

Perfect. And I think that really is one of the keys that we talk about when we think about ventilating a barn while we're agitating for manure. Most of the time those pump out covers are designed to be air outlets, right? They have a fan on it, and we have to be really thoughtful and cautious about, you know, removing those and let them become an inlet.

Brett Ramirez:

Yeah, and I was actually just thinking that was a perfect segue to that comment on, yeah. Since we ventilate using negative pressure, that means air is going to flow into the barn. And so what during pump out, that pump out opening is now a perfect inlet. And so we have to keep in mind that we now are going to be pulling air through that pump out cover, it's going to come off the headspace, pick up those gasses and end up in the pig space. So we do need to be very mindful about making sure that those are, you know, sealed as best we can, or making sure we got enough ventilation that if there is being gas pulled up, that it's not going to be at dangerous concentrations.

Dan Andersen:

Absolutely. And I think the other thing you pointed out is, oftentimes we're doing this during colder weather conditions. That cold air is heavy, it wants to pool down on that manure surface. And when we think about the chemistry of hydrogen sulfide, there's a few things we can say, right? It's denser than air, it has a rotten egg smell, but our nose is a poor detector in it, and then it's really dangerous, or potentially lethal to animals in human health. But anytime we're working with manure there, there is going to be some hydrogen sulfide coming off. It's it's more than saturated with sulfur in that manure. So you start knocking it around, you get this pool of sulfur on the surface of that manure. And that heavy air displacing that sulfur is really what we worry about and waking up to that pig zone.

Brett Ramirez:

Yep, exactly.

Dan Andersen:

So, from the ventilation standpoint, what are the critical moments when we're trying to set up that barn correctly for pumping and agitation, and what should we do? And what should we really be watching for?

Brett Ramirez:

So as we start that process, you know, the most important thing is really to make sure that, you know, among the other things that go into it from ventilation only, is that we are moving air. We gotta make sure we're getting enough air exchange that's going to dilute any of those concentrations, keep them below dangerous levels. And that's going to be, you know, all the barns are different, so it's some combination of some sidewall fans, some other pit fans, curtains being open, and really just making sure we're getting enough air exchange in there to prevent that concentration accumulation inside the barn. And now, as as we know from our normal ventilation that as you bring in more cold outside air, that means that's more cold outside air that's going to have to be heated up, which is not going to be something that's possible during pump out and agitation to keep everybody safe.

Dan Andersen:

Yeah. And I think one of the other things I've seen in some of my site visits to people who have had hydrogen sulfide issues is really being mindful of the pit fans. I mean, you pointed out that there's things we can do to help winterize our barn, make sure we're getting airflow where we want it from, but just general fan maintenance, and checking that those fans are working correctly and still have all their pieces on them is really important.

Brett Ramirez:

Yeah, and it's equally as important to make sure that after pump out, we plug them back in, we put them back we we get the pump out, cover sealed, or, you know, as tight as possible, so we don't have gaps around that. So it's, it's important, it is to make sure the correct ones are running and and or off. They need to go back in, because we still need to ventilate all winter.

Dan Andersen:

Is that something you recommend putting a little spray foam around a pump out cover or is it, it's sort of throwing, throwing good energy at a place that you can't do a whole lot?

Brett Ramirez:

Yeah, yeah, it's tough. I mean, because you need to get back into it, and next fall, you know, some people put a little spray foam, some just kind of weight it down. There's no real great solution to that, since you do need to take it off every year,

Dan Andersen:

Yeah. I mean, you could spray foam it, but you're going to break it all the time. But it is a short term solution, potentially for the winter. The other thing I wanted to mention right there is, is we sort of talked about how hydrogen sulfide pools in the surface. I think one of the most important things we can do is just making sure we have some headspace in the pit, really, before we start agitating that one or one and a half to two feet, is really important to make sure pit fans have room to draw air out of the barn. Make sure that if hydrogen sulfide is being emitted from that manure, which it will be, it doesn't come up and actually enter that animal zone. It has a place to go.

Brett Ramirez:

Yep, we need, we need space there. You know, as you start to tighten that space, it just, however deep that layer of hydrogen sulfide is is just, if it's closer to the slats, much more likely it's going to end up in the pig space.

Dan Andersen:

And as you've been talking about this, it's really a sort of a two part question, right? How fast is the hydrogen sulfide going to come out of the manure? We know it's going to come out, but how fast come out, but how fast is it coming out of the manure, and balancing that with the ventilation side. And I think you hit the ventilation side really well. But what are some things we can do on that the agitation side, to sort of slow or prolong the rate that hydrogen sulfide comes out of manure, to make sure that we can ventilate at a speed where we keep it at an okay concentration in the barn.

Brett Ramirez:

Yeah, I think on the agitation side we we just need to be mindful, right? We have some great best practices that I know you helped developed in making sure we're keeping the agitator under the manure. We're not spraying into corners, we're not getting it rooster tailing, and we're just kind of doing an overall good job at getting that that manure well mixed, and doing it in a mindful way that we're not causing excessive release of hydrogen sulfide or a rapid release of hydrogen sulfide,

Dan Andersen:

Absolutely. And I think one of the things we've seen in the past few years is beef barns, they're really open to the air, and we often think, well, that that shouldn't cause an issue, but they get some pretty good crusts on it and and we want to agitate and break up those crusts for for lots of reasons, get the nutrients out to the field, make sure that we don't have as many fly issues of larva and whatnot, living in that crust. But really, that's that's an important time, right? If we try and break up that crust, we are doing some surface agitation that can lead to rapid release, so making sure that we don't just keep hammering that all the time, trying to to break it up and then wait a little bit, break it up and then wait a little bit. Because repositioning those agitators, it's important. We want to try and clean out the barn as best we can, get as many of solids out as we can, but we want to let the ventilation system have some moments of catching up to make sure that we're we're in an okay position. I did want to talk a little bit more about ventilation, specifically during cold weather conditions, small pigs. What are some things that we can try and do to minimize stress on them while, while we're agitating and trying to make sure we're ventilating appropriately.

Brett Ramirez:

Yeah, this this one, right? This is the hard situation, small pigs, cold weather, and you got to agitate. You know, getting more pigs together, moving them, putting a little bit higher stocking density on the opposite side of the barn helps, as those pigs have the ability to huddle or pile. They're able to conserve some body heat a little bit better than otherwise, you know, making sure we don't over ventilate, even though, in this situation, over ventilating is not a bad thing. But having sick pigs that don't recover and don't spend more time on feed is also a pretty bad outcome as well. So we just kind of have to keep them together, keep them safe, and kind of little bit hope for the best and make sure we're doing the right agitation practices.

Dan Andersen:

Absolutely. I think that's that is the most challenging situation. There's no real right answer. Just do this an easy button on it. I think that is one of the times when I'm a little less I think you should wait until the soil is 50 degrees and cooling with manure. If you have that turn coming up and you know it's going to be struggle to to manage the barn ventilation with those small pigs, getting the manure out while the barn's empty has a great appeal to it. No one will be in the barn. There's no animals in the barn. You can really do a better job of getting that manure out.

Brett Ramirez:

I think the other point I'm just going to make on an empty barn, make sure we're running ventilation even when the barn's empty. That happens more times than I think we care to admit, but always keep men bent running even if there's no pigs in the barn.

Dan Andersen:

Absolutely, definitely great advice for safety. I think, while we're on this topic, I wanted to talk a little bit about what are some symptoms of hydrogen sulfide risks in in humans and in animals. And then maybe we can comment on what are some things you look for, sort of, if you're just agitating that barn, to say the animals are probably doing okay from hydrogen sulfide or or to notice signs of poor air or ventilation in the barn.

Brett Ramirez:

Yeah, you mentioned it earlier. The the easiest one is the odor. It's that rotten egg smell, and that's actually a pretty low concentration, that's less than two parts per million. And then kind of what's gonna happen is that concentration gets higher, and you're exposed to it longer, you might get some nausea, tearing, maybe headaches, fatigue, dizziness, and then when it gets pretty severe, coughing, eye irritation, and then eventually it can lead to unconsciousness and then death at the very high concentrations. For pigs, what you're going to want to be paying attention to is kind of, you know, signs of stress, if that's increased noise activity, things of that nature, where they're going to kind of indicate that they're in a stressful environment.

Dan Andersen:

And that's something that every few loads, or every so often, we should just be walking around trying to observe, paying attention to. And if you have one of those hydrogen sulfide meters, which I'm a big fan of, for $200 you can get a little information on what's going on, hold it next to a fan for the barn and see what's coming out, and get an idea of what the animals are being exposed. That always helps troubleshoot some of these issues and let you know where you're at, if you should hold off on agitating for a little while, trying to let the ventilation system catch up, or if you're staying in a pretty good position.

Brett Ramirez:

And I think on that point too, just remember, just because you're outside the barn doesn't mean you're necessarily safe, and you need to be just as cautious. Obviously, nobody should be inside the barn, but if you are standing near that pump out or near one of those exhaust fans that has some of those high concentrations, it's equally important to be mindful of that

Dan Andersen:

Sbsolutely, especially if you're going to hop in a big piece of equipment and start driving down the road. I mean that dizziness unconsciousness, right? It's really easy to lose control from just a moment, and you have to be on top of your game. Since we're on personal safety, what are some things we should talk about with our employees, so that they're all aware? And I mean, one of these that I've seen more frequently, than I'd like is sometimes we get people who want to come pressure wash a barn, and we get in a hurry to agitate it, and they aren't always aware of the risk. How do we communicate this better? What should we be doing to make sure that no one's entering that facility?

Unknown:

I think just your general communication, talking, texting, making sure they're aware, but then also signage on the barn and just make it very clear. You know, what has just happened, and what those best practices are, while they're in the barn. Because, you know, I think you and I both seen it as alright. They go into pressure wash. Water starts hitting the top, foam starts to break, bubbles start releasing more gasses, and then, generally, there's a spark, some ignition. So just having those procedures in place and making sure they're well communicated and posted are pretty important.

Dan Andersen:

Absolutely. And I think the other part of that is talking with everyone just so they. Know the risks, because oftentimes the first thing you see is someone passes out in a barn, and you're like, I'm going to go in and get them out, right? And it turns out it's, it's awful, pretty, oftentimes pretty challenging to hold your breath that long and carry someone. And oftentimes we end up with issues where it's a two for one, right? We end up with two people that go down instead of just one. So make sure you have a buddy, make sure you're tethered off, and make sure you have those emergency contacts, known so you know who you're going to call and trying to get that person to safety, but just being attentive to it and thinking, is this a good idea? Should I really be doing this, even if it slows you down a little bit is well worth the time spent?

Brett Ramirez:

Yeah, and I think, right, that's, that's the challenge with gas. You see somebody you know you care about go down, and your first instinct is to go in after them. And with gasses that you know you can't see and at really high concentrations, you might not be able to smell it, you got to kind of restrain that in instinct and get get the appropriate gear and or help to go help that person.

Dan Andersen:

And really it is about having a plan for each barn, I think. So, who are your safety contacts? Getting a contact ahead of time, who's setting up the ventilation system, getting that agreed to, what is their protocol, if you're the manure pumper, checking over their pump out fans, right? Are those fans actually working like they think they should be? And if you're not asking some of those questions.

Brett Ramirez:

Yeah, a nice checks and balances from you know, all the parties involved is a great advice.

Dan Andersen:

I think that takes us to the end of the questions I had for today. Is there anything you wanted to comment on that you think comment on that you think we missed?

Brett Ramirez:

No, I just say I think the most important is just really be mindful and communicate. I know we touched on it several times, but I think both of us can't stress enough how important is to, you know, talk, communicate, and just be aware of those risks and and the potential danger that is associated with this.

Dan Andersen:

I couldn't agree more. It certainly is a challenging situation. We do deal with some challenging ventilation periods in the winter, as it gets cold, and we have to try and make the best out of some bad situations, but it is communicating, understanding what the risks are, and how we can minimize them. So I want to thank you for your time today, Brett. It was great to talk to you and hear some of the things we can do to try and minimize our hydrogen sulfide risk for both ourselves and animals.

Brett Ramirez:

Yeah, thanks, Dan. Appreciate being on.

Dan Andersen:

Thank you for joining this installment of Talkin' Crap. Be sure to take a look at the show notes on our website for links and materials mentioned in the episode. For more information or to get in touch, go to our website, www.extension.iastate.edu/immag/. If you found what you heard today useful or it made you think, we hope you subscribe to the show on your podcast app of choice. Signing off from a job that sometimes smells but never stinks, keep on talking crap.