On the Move

WHEN AND WHERE DO MANURE SPILLS OCCUR?

A study of incident reports over the years revealed some manure spill trends.

by Reed Kostelny

Manure spills are a real obstacle for any livestock operation and any custom applicator. They may stop application for the day or require outside equipment to be hired for quick cleanup. Adding together the troublesome time costs and environmental impacts of manure spills, it is always worthwhile to look for ways to avoid them.

As an intern for University of Wisconsin-Madison Extension’s Conservation Professional Training Program, a previous intern (Racheal Osterhaus) and I researched manure spills and runoff incidents that happened in Wisconsin over a five-year period (2015 to 2019). We were looking for common issues and improvements that could be made. By looking through paper and electronic files kept by the Wisconsin Department of Natural Resources (WDNR) and county agencies, 729 spills were found. While evaluating these spills, we focused on collecting information about the root causes, impacts, and the commonalities between spills.

Where spills occur

The first piece of data to look at is where these manure spills take place. We broke the spills into three categories: 1. During transport 2. On the farm 3. During or after application

Spills most often happened when manure was being transported from the farm to the field (Figure 1). Problems during transportation include incidents like tankers tipping over, accidental valve openings, and dragline leaks. Transportation events have become more frequent, with transport being a cause in 38% of all spills from 2015 to 2019. That was up from 31% between 2010 and 2014.

On-farm spills followed closely behind in number of incidents, and between 2015 and 2019, this category represented another 38% of spills. Examples of these would be a manure storage overtopping, barnyard runoff, and transfer pipe failures. This is a smaller percentage of spills when compared to the 2010 to 2014 period, when 40% of spills occurred on the farm.

The final location for spills to happen was during or after land application. This is where problems like equipment breakdown or malfunction and runoff due to rain or snowmelt can occur. Overall, the percent of all spills from land application declined. From 2010 to 2014 land application represented 27% of incidents, but it fell to 23% of all spills from 2015 to 2019. Location was unable to be determined for the remaining 1% of manure spill incidents.

Figure 1. Where did the manure spills occur?

50%

40%

30%

20%

10% ■ 2010 to 2014 ■ 2015 to 2019

0%

Farm Transportation Land application

The proportion of all spills that occurred in each location in both five-year periods. Spills with unknown locations were less than 1% of the total. N=520 for 2010 to 2014 and N=729 for 2015 to 2019.

Tools and training

Extra focus on particular problems can help prevent spills. On-farm issues, like a manure storage overtopping, can be prevented with frequent monitoring of manure levels, equipment maintenance, and diverting as much clean water away from the manure storage as possible.

In a previous study (2005 to 2009),

Figure 2. Who reported the incident? Figure 3. When did transportation spills take place?

17% Unknown

11.9% Neighbor

14.8% Inspection 2.1% Other

11% Agency

5.5% Manure hauler 37.7% Farmer Number of spills

60

50

40

30

20

10

0

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec ■ Custom manure haulers ■ No custom hauler

The primary reporting party recorded for each incident between 2015 and 2019. N=729. The total number of spills that occurred during transportation each month. N=80 for spills with a custom manure hauler involved and N=196 for spills without a custom manure hauler.

the number of manure storages overtopping in August (during summer with maximum evaporation) was just as high as in April. Implementation of weekly monitoring and installing markers in the manure storage that show the maximum operating level have made a significant difference.

During transportation, spills involving operator error, such as equipment tipping over and accidental valve openings, can be avoided with proper training and equipment familiarity. Spills that occur during or after land application, such as contaminated runoff leaving the field, can be reduced by checking resources like weather reports and manure spreading advisories each day. Injection and/or immediate incorporation also minimizes these risks.

The right reports

Focus should also be placed on reporting, so that proper cleanup is confirmed and possible environmental impacts can be prevented. The data we collected relies entirely on spills and runoff events that are reported and recorded.

In most states, the responsible party (livestock producer and/or manure hauler) is required to report an incident. Ideally, every incident would be self-reported, but we found that only about 43% of spills were self-reported by either the farmer or the manure hauler (Figure 2). That means 57% were reported by someone else — neighbors or a local or state agency — or were found during inspections. Seventeen percent of spills didn’t specify the reporting party.

Many pieces of data were collected to go along with each spill. Date and location were recorded, as well as information such as whether a custom manure hauler was involved and what sort of environmental impacts were observed.

One of the clearer trends we found was the time of year that spills occurred. Most spills occurred in spring and fall, and specifically in the months of April, May, October, and November.

Another interesting trend was the involvement of custom manure haulers. Custom manure haulers transport over two-thirds of the manure in Wisconsin, but they were only a part of about 29% of spills during transportation (Figure 3).

Some other highlights include: • Surface waters were impacted in 45% of spills (including road ditches with standing water that may not have connected to a stream). • The most common spill volume was between 50 and 1,000 gallons. • Of the 729 spills, 62% went through the Wisconsin DNR spills telephone hotline. • The years 2018 and 2019 were wetter than normal, and as a result, these two years alone represented 61% of manure storages overtopping between 2015 and 2019.

Goals of the project

This is the third five-year manure spill study conducted by the University of Wisconsin-Extension, in partnership with the Professional Nutrient Applicators Association of Wisconsin and the Wisconsin DNR. Despite the growing number of manure spill cases that have been recorded in each subsequent fiveyear study, experts and agency staff do not believe that the number of manure incidents is increasing. Instead, more spills are just being documented.

“Farmers and manure applicators are much more willing to self-report, because they’ve learned it’s the right thing to do and because it’s better to self-report than have a neighbor or citizen report a problem first,” noted University of Wisconsin-Madison Division of Extension’s Kevin Erb.

This data will be used to refocus education efforts in the state and improve methods of recording and dealing with manure spills. The trends seen in Wisconsin could be used to help shape reporting and responses in other states as well. ■

The author is an intern with the University of WisconsinExtension’s Conservation Professional Training Program.

A pilot zeolite filter connected to a covered pit receiving waste water from a flush system cut ammonia emissions.

Clear the air with zeolites

A zeolite filter reduced ammonia and odor emissions from dairy cattle manure.

by Mario de Haro-Martí

Modern dairy production concentrates the number of animals housed in relatively small areas to improve production efficiencies, output per animal, and take advantage of economies of scale. This concentration of animals, greater feed inputs, and intensive management also concentrates by-products like manure and increases some air emissions, including ammonia and odors, which are among the most noticeable at the local and regional levels.

Diverse emissions reduction and control techniques are needed and can be applied at several stages of livestock production. In general, there is no single practice or process that can take care of all emissions from a livestock facility. Producers need a palette of options to choose from, based on their individual production conditions, geographical location, climate, management styles, needs on emissions reduction outcomes, and many other unique parameters.

One technology that can be added to the palette of options now is zeolite filtration. Zeolites are a group of minerals that are the result of volcanic eruptions millions of years ago. They are widely available around the world, and we have several mines in the U.S., including some in Idaho.

Some of their characteristics include a relatively low density, high porosity, high water retention, high cation exchange capacity (CEC), and the capacity of adsorbing a diverse variety of compounds, cations, and gases that can be exchanged depending on their

Ammonia concentration before and after treatment

3 -N mg/m

3 NH 6

5

4

3

2

1

0 0.43 0.48

BKGR (p=0.001) 6/10/2015

BKGR (p=0.001) 6/20/2015 5.29

29.9 30.8

INLET (p=0.001) Period 1 7/2/2015 0.42

OUT (p=0.001) Period 1 7/2/2015 24.9 25.8

2.75

0.27 10.4 1.78

10.5 1.02

INLET (p=0.001) Period 2 9/9/2015

OUT (p=0.0001) Period 2 9/9/2015

INLET (p=0.13) Period 3 10/31/2015

OUT (p=0.13) Period 3 10/31/2015

Period and sampling date

Ammonia concentration before (gray) and after treatment in the filter (red), background ammonia air concentration (dark blue), and the average temperature at inlet and inside the filter (orange). 35

30

25

20

15

10

0

charge, molecular size, and concentration. The most common and abundant zeolite is called clinoptilolite, and it has a wide variety of uses in water purification, agriculture, and industry.

The University of Idaho teamed up with a dairy producer in southern Idaho to test a pilot zeolite filter connected to a covered pit receiving the wastewater from a flush system. The liquid manure in the pit is the most concentrated one in the system. From the pit, the manure was pumped to a set of solid separators and then a centrifuge.

Air from the receiving manure pit was extracted using a fan connected to a variable frequency drive actuated by floats, varying the fan speed according to the flow of liquid and subsequent air displacement. Ducts diverted the air to the zeolite filter. The pilot filter had a top to bottom flow, and it can be set up with different volumes of media, from one or two small layers up to a full bed. The media, in this case, was clinoptilolite.

Effective on the farm

Ammonia emissions were monitored for a series of running periods accumulating a total of approximately two months of running time with an off period to test ammonia diffusion in the system. On the first days of monitoring, the filter achieved a 92% ammonia reduction.

A second monitoring period was done after having the filter off for about two months to check for ammonia diffusion within the filter and performance at different temperatures. Ammonia reduction was 90% on this second run, suggesting no gas diffusion when the filter fan is not operating. At this second run, the odor concentration was also measured, achieving a 45% odor concentration reduction, even when using the blower at maximum speed, with a minimum residence time in the filter of approximately 0.9 seconds.

After the second sampling period, the filter was running continuously until Day 59 of operation, when it reached a 43% reduction in ammonia under colder temperatures. These results demonstrate the high effectiveness of the pilot filter, especially considering that it was handling the liquid manure flow from two dairies housing a total of 4,800 Holstein cows.

A viable option

Using zeolite filters to reduce ammonia and odor emissions is a viable technology that can help livestock producers reduce their impact, retain valuable nitrogen in a manageable form, and improve community relationships. Filters using these principles and media can reduce emissions from manure collection and transfer pits, storage or treatment ponds, forced aerated composting operations, and any other setting where the airflow can be captured and ducted to the filter.

Zeolites are relatively low-cost and available in the western U.S. When saturated, they can be crushed and applied to agricultural soils where microbes and crops can extract the nitrogen held in them. It is also possible to regenerate the zeolites to be reused again. This option wasn’t studied in these trials, but other researchers have regenerated them up to a certain point.

Another advantage of the zeolite filter is that it can run independently of weather conditions. It doesn’t need moisture, and it runs under a wide range of temperatures. Of course, ammonia adsorption declines as temperature drops, as do ammonia emissions from manure. Winter operations will see a higher benefit on the odor reduction than from the ammonia control. A journal article describing the research was published at the Transactions of the ASABE.

The use of clinoptilolite as air emissions control technology for dairy and other livestock operations is another option available for our producers. ■

The author is an extension educator for the University of Idaho Extension.

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Variability is the rule

Recognizing the changing characteristics of manure can help make the most of this valuable resource.

by Scott Fleming

While it all fits under the loose term of “manure,” if you’re reading this, you well know that all manure is not the same. And while we can categorize it by source, that doesn’t remove the variability that exists across its many facets.

Manure has gained a “difficult-to-manage” reputation as fertilizer, but it doesn’t have to be. With systematic manure analysis and an understanding of all contributing factors, its variability can be identified and this resource turned into a valuable fertilizer.

A look at phosphorus

Phosphorus is generally the most regulated component in manure. This is due to the risk of phosphorous delivery to surface water. When phosphorus runoff travels to surface water it can cause excessive algae growth.

The great news about phosphorus management is that this element tends to stay put in the environment. Soil erosion and manure runoff are the most likely culprits leading to phosphorus runoff. There is also a soluble phosphorus component to manure, but it is minor. With sound tillage and rotation practices, as well as effective incorporation, the risk of phosphorus runoff can be minimized.

Phosphorus content in manure tends to vary slightly during manure application. High phosphorus concentrations are commonly associated with manure that is high in solids content. This is especially true in a multistage manure storage structure.

At a minimum, a manure sample should be pulled at the start and finish of each stage. A more comprehensive approach would include additional sampling when manure consistency changes. The only way to identify this variability is through a thorough sampling program. To get the most from manure, establish a thorough sampling plan to determine the variability in nutrient content prior to application.

Working with nitrogen

Nitrogen may be the single largest reason growers are applying manure. It is a great source of fertilizer for next year’s nitrogen-demanding crop. Nitrogen is also one of the toughest nutrients to control when it comes to applying manure. Nitrogen in manure can vary from the beginning of application until the last hose is on the reel.

To further complicate management, nitrogen is very mobile in the soil profile. If a warm or wet fall is in store, nitrogen could be lost through the bottom of the system due to leaching. The same problem can occur in a warm or wet spring.

To help manage loss of fall-applied manure to the environment, it is best to apply manure when soil temperatures are below 50°F. If application cannot be delayed, many nitrogen stabilizer products are available.

Nitrogen can also be lost to the atmosphere thanks to volatilization. This can be controlled by the manure application method as well as nitrogen stabilizer products.

The hard and fast rule to limit volatilization is simple: The faster the manure gets mixed with the soil, the more nitrogen you will have for your crop. Limiting manure’s exposure to the air reduces its potential for volatilization.

Injection is the best way to maximize

the amount of nitrogen available, followed by prompt incorporation. Surface application comes in at a distant third. This is an effect of the loss of nitrogen to the atmosphere when it lays on the soil surface. These losses to volatilization occur from the moment manure is applied to the field. Obviously, minimizing these losses can prove beneficial to the environment and the bottom line.

The Wisconsin nitrogen calculation method is fairly straightforward, so it’s easy to utilize in an example. When direct-injecting liquid dairy or beef manure, 50% of the total nitrogen is available in the first year. If the manure is surface applied and incorporated within 72 hours, 40% of the total nitrogen is available to the crop.

If the manure is not incorporated within 72 hours, only 30% of the manure’s total nitrogen will be available for the crop. The remainder of the nitrogen in each of these scenarios is either lost to volatilization, or it is slow-release nitrogen and will become available in the second and third year after application.

It is also important to note that different sources of manure have different first-year nitrogen availability. For example, swine manure has 65%, 50%, and 40% first-year availability when injected, incorporated, or surface applied, respectively. Check resources from your state for more specific information about nutrient availability.

In addition to source and application method variation, there is also variation of manure from farm to farm. Some likely causes for this variation include diet, precipitation, manure handling and transfer method, and animal size and type. To further complicate matters, the manure within a storage structure will vary enough to merit additional analysis. To account for this variability, manure analysis must be performed on a regular basis throughout the application season.

SUPPLIER FORUM

• Liquid Manure Handling • Solid Manure Handling • Trucking • Pushing & Packing

Sampling for consistency

As discussed earlier, much of the variation in manure tends to follow the concentration of solids. For a permitted livestock operation, a minimum of one composite sample per source is required for each application period. In a multistage manure system, this would mean one sample per stage. Additional manure samples should be pulled for all solid or composted manure.

This is the bare minimum sampling strategy that should be employed. Ideally, pull additional samples after major changes in manure consistency, prolonged application delays, and on each manure transfer field.

When looking at the impressive fertilizer value of manure, it is best to take sampling more seriously than meeting the minimum requirements. After all, you could pay for more than 10 manure samples by saving just 1 ton of urea. While the relative cost of manure analysis may be low in comparison to fertilizer, managing the sampling strategy is still necessary to provide useful data. If too many manure samples are pulled, the data could become overwhelming and would likely not drive additional management changes.

A strategy commonly employed is sampling when switching fields. This will allow the producer the opportunity to tailor commercial applications to the exact manure credit for that field. Another important time to sample would be following a shutdown. The manure composition could change and this may cause variability.

If manure is applied to land that is not under the control of the farm applying the manure, this is a great opportunity to pull a sample. It provides peace of mind and helps show value for the manure application.

Manure sampling strategies are almost as variable as manure itself. Creating a game plan prior to application season will help direct sampling efforts and improve efficiency. Start pulling manure samples with purpose and putting them to use, and reap the value of this readily available resource. ■

The author is a nutrient management specialist and sampling director at Rock River Laboratory in Watertown, Wis.