South St. Paul Community and Sanimax

This is a transcription of the question-and-answer session which followed the Sanimax community update on February 20, 2025. Answering questions are Jordan Unser, Director of USA Operations and Tony Colombari, Senior Consultant with Trinity Consultants.

Question: What does Sanimax do on a regular basis to make sure the odors that are being released are not harmful/hazardous?

Jordan: Sanimax does not emit any hazardous air pollutants or HAPS. At Sanimax, we have our team that’s not only testing for HAPS, but also for air toxins, and I can confirm that we do not emit any. I understand that in addition to health concerns from odors, there are concerns of odor nuisance and odor having a negative impact on quality of life in our community. That’s why we’re focusing on the odor improvement plan – the odors are not hazardous, but they do impact quality of life. This is where investments in technology and process controls are really coming into play.

Question: Why did Sanimax choose a Venturi scrubber for odor control versus other technologies such as RTO?

Jordan: An RTO – Regenerative Thermal Oxidizer – is another type of air control technology for removing organic compounds, HAPS, and different types of odors. At our Green Bay, WI facility, we installed an RTO several years ago. It was not as effective as we needed it to be in cold weather. RTOs are very common in the southern USA where cool water is more scarce. In the Midwest, the effectiveness of the RTO was not what we expected or needed. We removed the RTO in Green Bay and put in place the Venturi scrubber. 

With our experience in Green Bay with the RTO, we chose the Venturi scrubber for our South St. Paul facility. We added the same Venturi scrubber to accompany the scrubber system we already had in place. This allowed us to introduce this piece of equipment into a series of existing equipment so that we could get more effective odor removal through multiple stages that we wouldn’t have gotten with other technology. In addition to that, there is an added emission control piece. We recently went through air stack testing after implementing the new scrubber, and we had a significant reduction in what we were emitting from a particulate standpoint with the new equipment in place.

Question: Does the new scrubber system have enough capacity to support the new cooker Sanimax put in?

Jordan: Yes. The design and implementation process of the new cooker was about 17 months. We began designing the new cooking system in parallel with designing the odor scrubber system. We did this to ensure that the new efficiency and odor control equipment could support the new cooking equipment that was going to be installed.

Question: Since there are no more stockyards in South St. Paul, why is the rendering plant still in this location? 

Jordan: In recent years, residents of South St. Paul have seen the stockyards start to diminish and move to other locations. The Sanimax facility was originally built around the proximity to transportation, but also proximity to where the material was going to be coming from. While the stockyards are not necessarily right here in South St. Paul anymore, the advantage of this proximity is still relatively central to the agricultural industry. From a transportation standpoint, the ability to service through rail eliminates truck miles from the roadway. It’s kind of a two-pronged approach of being well within proximity of the local ag industry, but also supports transportation.

Question: What sort of impact has this process had on the air quality in South St. Paul?

Jordan: Sanimax’s emissions or particulate matter are within what the MPCA (MN Pollution Control Agency) considers to be an insignificant threshold. As we introduce new equipment, we model around a worst-case scenario that we’re processing at maximum output 24/7 so that there’s nothing missed. We put in the new equipment and did stack testing for emissions and particulate control. Even with the model of a worst-case scenario, we were less than 20% of the permitted threshold. This also falls in line with the Clean Air Act and National Ambient Air Quality standards.

Question: Could you explain how the third phase of the scrubbers work? 

Jordan: The new Venturi scrubber was built into a series of scrubbers that have three different phases. The intent of the Venturi scrubber is to remove particulates. The first scrubber removes particulates and the first series of odors which are nitrogen-based malodors. The second phase is an additional round of particulate capture, while also removing the sulfur-based malodors. And then the third and final phase before the air is discharged is our polishing stage, which is the final treatment.

Question: Is there just one scrubber and one new cooker? 

Jordan: Yes. One new cooker was installed, and one new Venturi scrubber was installed. The scrubber system is a combination three-series system. Really, you have three scrubbers in a series to remove all those different odorous compounds in combination with the particulate removal.

Question: How much of the market does Sanimax hold, AKA how much are you recycling and how much is not being recycled?

Jordan: In Minnesota specifically, there is a significant risk if we’re not able to render this product. In partnership with the MPCA and the Department of Animal Health and the Department of Agriculture, when we looked at having to replace this cooker, it was really a team effort that looked at the environment to make a determination: if we’re not able to capture this material, it poses a significant risk or threat to Minnesota landfills, which are already pushing capacity. There are efforts in place to reduce contributions to landfills. While I don’t have the exact number of the market specifically, I will say that the role that Sanimax plays in Minnesota, the Sanimax-South St. Paul facility is critical to the landscape from an environmental standpoint.

Question: The site is meeting the Clean Air Act ambient air standard. Is that based on how you currently operate or how you could operate in the future if you ran more?

Tony: When Trinity Consultants helps with the air permit application, we do that permit application looking at worst-case hypotheticals. If the plant were to be running 24/7 at maximum rates, at their maximum permitted at emission rate, the air dispersion modeling looks at that type of operation 24/7 and including nearby sources that are operating 24/7 and the ambient concentration in the surrounding area. It’s a really conservative modeling analysis that looks at hypothetical worst case. The fact that the plant is not operating 24/7, and the stack test emission rate was 20% of that permit limit would mean the air quality is better than what the hypothetical modeling showed. But even that hypothetical worst-case modeling was below all the ambient air quality standards.

Question: What does loading and unloading look like? How are incoming waste and outgoing products? 

Jordan: This is part of our odor improvement strategy and something that we’ve really locked in on optimizing in the past year. It’s a two-pronged approach in partnership with our raw material suppliers and how we operate the plant. Raw material typically comes in on bulk-loaded trucks in large quantities from farmers and slaughterhouses. We also have route trucks which are servicing a lot of the local restaurants, butcher shops, and grocery stores. The raw material coming in on trucks is covered with a tarp. 

Upon arrival at the plant, the goal is to immediately be able to bring the trailer inside our facility and unload that material. The ability to do this depends on our backlog and making sure we have capacity for the material. While the new cooker does have a larger capacity, we didn’t install it because we planned a higher volume of material. One of the key components of the new cooker is that it allows us to process the material in a timelier manner, which prevents us from having product sitting outdoors waiting to be unloaded. 

Sometimes we are at the mercy of the environment and the agricultural industry, but we do our best to optimize our approach to unloading trailers. If we have to have trailers sitting outside, they move to our misting station, where they’re being misted with a component that helps eliminate odors while they’re pending unload. 

Focusing on our partnerships with our suppliers and making our process more effective and efficient, we’ve been able to significantly decrease the waiting time for unloading the material into our facility.

Question: What tools does the MPCA have to enforce that Sanimax is operating within MPCA allowable levels?

Jordan: We won’t speak on behalf of the MPCA, but there are a few things I can comment on. The stack testing that we did was in partnership with the MPCA to ensure that the limits that we set in place were proven and not exceeded. We have a third-party consultant come in and they’re doing continuous air monitor testing of our outgoing discharge stacks, which is collecting PM (particulate matter) 2.5 and PM 10 at normal operating conditions to ensure that it’s not exceeding those levels set by the MPCA.

Question: The only other option is sending material to landfill?

Jordan: Simply put, yes. There are really two main options outside of rendering. You have landfilling or composting on farms. The risk with either of these options is running into animal health issues.  Historically, we’ve seen in both the USA and other countries where rendering isn’t available, and the material isn’t appropriately managed at a landfill. With this, you start getting into animal health and disease outbreak issues. While the product could go to landfill, that’s not the ideal path, the landfills will fill very quickly.

Question: What is the average wait time in truck for unprocessed organic rendering material?

Jordan: There’s been significant progress for us in partnership with our supplies and with optimizing our internal systems – when a truck comes on site, we’re able to immediately bring it into our facility and unload that so we don’t have a backlog. Now there are times that there is a system upset or there’s a delay in arrivals that could result in material that has to wait to be unloaded. But we really look to minimize that within a one-two hour timeframe, so nothing is having to be held in a trailer for an extended period of time. The middle of February was a great example of having extreme cold temperatures.  Suppliers ran into issues; transportation companies ran into issues… that caused upsets. Through some of the changes that we’ve made, it’s really kept us at a minimal trailer unload backlog.

Question: Are you running the old cooker with old air emissions?

Jordan: Prior to the new cooker being installed, we had two identical cookers – a newer one and an older unit. When we brought the new unit in, the oldest unit was removed from service. Today we have the newer existing unit and the brand-new unit. They are running in parallel.  When we did the stack testing, both of those units were running. It proved that even with both units running and the emission control equipment in place, we were still under 20% of our permitted emission rate.

Question: Will the community webpage be updated with more information about your company?

Jordan: As we look to optimize the website, we want to make sure that as equipment’s installed or as we make process changes that we’re sharing those updates. We also want to be transparent that if we run into an issue, we’re able to share that on the community webpage as well. It’d be irresponsible for me to sit here and say there’s never going to be another odor incident in South St. Paul. What I can commit to is that we’re going to make significant improvement with the equipment that we put into place last year, and we will continue to build upon it in the future.

Question: Why weren’t any of these (odor abatement) efforts made before the lawsuits in South St. Paul?

Jordan: I joined the company 18 months ago, and one of my main focus areas was taking the right steps with the community to figure out how we can work in partnership. I understand there’s been challenges. I know there’s been resistance built up there, but I’ve put in a tremendous amount of effort with the City of South St. Paul, the MPCA, and the local community to try and engage. I understand what the challenges were, but I am also sharing out our plan of what we are going to do. I fully understand that there have been challenges and concerns in the past, but my main focus is looking forward on the changes that we’ve already put in place, and the ongoing or long-term plan we are continuing to build.