New and Innovative Technology – Livestock and Poultry Environmental Learning Community

April 30, 2019June 6, 2019

Side-dressing Emerged Corn with Liquid Livestock Manure

The application of livestock manure to farm fields has always been an expense for producers. On-farm research plots were assessed in Ohio following application of liquid swine and liquid dairy manure using drag hoses to provide side-dress nitrogen to emerged corn. A six-inch diameter drag hose was used to side-dress corn with swine finishing manure at the V3 stage for four crop seasons. The manure was incorporated at a rate of 6,500 gallons per acre to replace purchased commercial side-dress nitrogen. Plot yield results indicated liquid swine manure produced higher yields when compared to 28% urea ammonium nitrate fertilizer when applied at similar nitrogen levels and the cost savings on purchased fertilizer paid for the manure application cost. The use of liquid manure to sidedress corn can provide a new window of time for manure application in Ohio and apply manure when the nutrients could be utilized by a growing crop.

Purpose

The process of applying liquid swine finishing manure to farm fields represents a significant expense for livestock producers despite the value of the nitrogen, phosphorus and potash contained in the manure. Ohio farmers continue to reduce wheat acreage shifting more of their manure application to the fall application window. The ammonium nitrogen in fall-applied manure is subject to loss before a crop is planted the following season. In the Western Lake Erie Basin of Ohio, an area over three million acres in size, surveys have shown approximate half the livestock manure generated annually is applied in the fall after crops are harvested (Zhang et al., 2015). This allows much of the manure nitrogen to be lost to leaching before the following crop season. Recent research has determined the amount of nitrogen entering Lake Erie influences the toxicity of the hazardous algae blooms.

The ammonium nitrogen in fall applied swine finishing manure can be captured by growing cover crops. A fall cover crop study (Sundermeier, 2010) indicated that an actively growing radish crop reduced soil nitrate nitrogen levels from 21.3 ppm to 6.5 ppm. This prevented the nitrogen from being lost from the field, but only a portion of the organic matter created would mineralize the following crop season to provide nitrogen for a growing crop.

The incorporation of swine finishing manure directly into a growing corn crop with a manure tanker has proven to provide corn yields similar to commercial fertilizer (Arnold et al., 2017). However, Arnold et al. noted soil compaction was a concern with the heavy manure tanker. Using a drag hose to incorporate the manure into emerged corn should overcome the soil compaction concern and allow the corn crop to utilize the available nitrogen in the swine finishing manure. The money saved by not needing to purchase commercial nitrogen to side-dress the corn crop could exceed the cost of the manure application.

What did we do?

This study was designed to determine whether the ammonium nitrogen in liquid swine finishing manure could produce corn yields similar to commercial 28% urea ammonium nitrate (UAN) when the manure was side-dressed on emerged corn using an injection toolbar and soft drag hose (Figure 1).

Figure 1. Side-dressing V2 corn with liquid manure.

In each of the four years of this complete block design study, started in 2014, manure was incorporated at a rate of 6,500 gallons per acre to provide approximately 210 pounds per acre of nitrogen. The 28% UAN treatment was applied at approximately 70 gallons per acre to provide 210 pounds of nitrogen per acre. All treatments also received 10 gallons of 28 percent UAN as a row starter fertilizer at planting time to provide approximately 30 pounds of nitrogen. The two treatments (manure and commercial fertilizer) were replicated three times each season.

Figure 2. Manure drag hose across V3 corn.

To fit the needs of the commercial manure drag hose operator, each year the corn fields were planted at a 45 degree angle with a 12-row planter using auto-steer. This allowed the commercial manure applicator to stretch the empty manure hose diagonally across the field from one corner to the other at the start of the manure application process (Figure 2).This divided the square field into two triangles and the applicator could apply manure to the entire field without the need of a second tractor to assist in moving the full manure hose. The field had 36 rows (90 feet) of end rows completely around each field allowing the drag hose operator sufficient room to make turns and keep the manure within the boundaries of the field.

The manure came from a 2,450 head swine finishing building with an eight foot deep pit under the animals. This finishing building design is common in Ohio. The manure was pumped through an eight inch diameter hose to the edge of the corn field. A six inch diameter drag hose was pulled across the field during the manure application process.

Figure 3. Drag hose damage caused the corn to lean for about a day.

The corn flattened by the hose typically recovered, i.e. was standing upright, by the following day (Figure 3). The pressure in the hose at the building was more than 200 pounds per square inch. The hose pressure at the toolbar in the field was approximately 30 pounds per square inch. The flow rate was typically between 1,400 and 2,000 gallons per minute depending on the type of pumping equipment used, the diameter of the hoses used, and the distance from the manure storage site to the field during each of the four years.

Manure samples were collected and analyzed during the application process each season. The nitrogen, phosphorus and potassium content of the manure was similar each year so application rates were kept the same each season. The analysis indicated the manure contained 32.1 pounds of available nitrogen, 18.0 pounds of P₂0₅ and 24.9 of K₂0 per 1,000 gallons (Table 1).

Table 1. Average nutrient analysis of swine finishing manure applied.
Nutrient	Pounds per 1,000 gallons
Total Nitrogen	34.3
Ammonium Nitrogen (NH4)	31.0
Organic Nitrogen	2.2
Available Nitrogen	32.1
Phosphorus (P2O5)	18.0
Potash (K2O)	24.9

The liquid manure application toolbar had rolling coulter manure application units with a wavy coulter tilling up a strip of soil approximately six inches deep and three inches wide. The manure boot applied manure over the tilled strip and the manure was covered by a pair of notched soil closing wheels. Treatments were approximately 1,200 feet long and 30 feet (12 rows) wide. The auto-steer unit used for planting the crop was transferred from the planting tractor to the 275 horsepower tillage tractor, attached to the toolbar and drag hose, for the manure application. The center unit on the toolbar was removed to prevent tillage and manure application to the center row. This enabled the drag hose to ride higher on the soil surface and lessen the scouring of the field. The manure for the center row was diverted to each side so each side received 150% of the normal manure application rate.

In each year of the study manure was not applied to three strips, 12 rows wide, in each field. These strips were fertilized with 28% UAN the same day with the same rate of nitrogen contained in the swine finishing manure. These commercial fertilizer strips did, however, have the drag hose pulled across them as the commercial manure applicator applied manure to all other parts of the fields. Commercial 28% UAN was applied to the ends of the corn fields and edges of the corn fields where the swine manure could not be incorporated.

The fields were no-till or minimum-till and the previous crop each year was soybeans. Plant population counts were conducted each year of the study. The predominant soil type in the fields were Blount Silt loam, end moraine 0 to 2 or 2 to 4% slopes

Soil samples of each of the four fields in this study showed P₂0₅ and K₂0 levels to be in the maintenance range. The Mehlich III P₂0₅ levels ranged from 59 to 81 ppm and the K₂0 levels ranged from 149 ppm to 184 ppm (Table 2).

Table 2. Annual soil nutrient test results (Mehlich III).
	Year
	2014	2015	2016	2017
pH	6.7	7.0	7.0	6.8
Organic Matter (%)	2.9	2.5	2.6	2.8
P₂O₅ (ppm)	66	76	81	59
K₂O (ppm)	161	149	162	184

At harvest time each year, yields and moisture data were collected using the combine’s monitor. The monitor was calibrated each season before the manure side-dress plots were harvested. All yields were adjusted for moisture. Yield data were analyzed by ANOVA at the 0.10 probability level.

What we have learned?

Over the four years of this study the incorporated swine finishing manure treatments increased yields when compared to the incorporated 28% UAN treatments by an average of 14.8 bushels per acre (Table 3). This varied from no yield increase the 1st year (2014) to 33 bushel per acre yield increase in 2015, an unusually wet growing season.

Table 3. Corn yield for treatments comparing nitrogen applied as UAN at planting to side-dressed hog manure. Subscript letters a and b indicate yields that year were statistically different using ANOVA at 0.10 probability level.
	Yield in Bushels per Acre
Treatments	2014	2015	2016	2017	4-year ave.
Incorporated 28 percent UAN	204	121_a	216_a	145_a	171.5
Incorporated swine manure	204	154_b	222_b	165_b	186.3
Least Significant Difference (0.10)	17.65	15.57	2.37	0.19
Coefficient of Variability	2.45	4.74	0.62	0.39

The normal accumulated precipitation for the growing season (April 1 through September 30) in this area of Ohio is 23.3 inches. The 2015 season was much wetter than normal, and the 2016 season was drier than normal (Table 4).

Table 4. Annual planting dates and normal and observed temperature and precipitation data from April 1 through September 30.
	Year
	2014	2015	2016	2017
Corn planting date	April 25	May 15	April 20	June 1
Normal precipitation (inches)	23.3	23.3	23.3	23.3
Actual precipitation (inches)	21.0	32.6	16.5	23.6
Historical average temp (°F)	65.7	65.7	65.7	65.7
Actual average temp (°F)	65.3	66.2	67.2	65.9
Average high temp (°F)	76.8	77.6	78.8	77.4
Average low temp (°F)	54.8	55.8	56.7	55.4
Total growing degree days	2,876	3,006	3,272	2,960

The application of 6,500 gallons per acre of swine finishing manure supplied approximately 210 pounds per acre of side-dress nitrogen for the corn crop while also supplying sufficient phosphorus and potash for the corn crop and the soybean crop the following year without applying excessive phosphorus (Table 5).

Table 5. Nutrient balance of swine finishing manure side-dress of corn. Nutrient removal rates are from Vitosh et al., 2003 (Tri-State Soil Fertility Guide).
Crop	Nutrient removal in pounds per bushel: 200 bushel per acre corn crop followed by a 60 bushel per acre soybean crop				Available nitrogen (ammonium nitrogen + half the organic nitrogen)
	P₂0₅	K₂0	P₂0₅	K₂0	N
Corn	0.37	0.27	74	48
Soybeans	0.80	1.40	54	84
Total nutrients removed			122	138
Nutrient content of 6,500 gallons of swine finishing manure applied			117	162	210
Net nutrients			-5	+24

In the first year of this study (2014) the field conditions for manure application were less than ideal. The field was wet and the drag hose scoured more than an inch of soil from the field resulting in some of the V1 corn plants being buried and others being pulled out. This reduced the final plant population of the corn rows next to the drag hose by approximately three thousand plants per acre. In each of the following seasons, when V3 plants were side-dressed, the field conditions were firmer and stand loss from the drag hose was not an issue. This stand reduction may have been the reason why 2014 was the only season in which manure did not yield statistically better than the commercial fertilizer.

The hose dragged across emerged plants caused an obvious lean immediately after the application process. By the following day all the plants were upright again. Stand counts indicated approximately 32,000 plants per acre across both treatments in the 2015, 2016, and 2017 seasons.

The 2015 crop season had the largest difference in crop yields between the treatments. Rainfall that season was more than nine inches above normal (Table 4). Most of this extra rainfall fell during the 35 days following the side-dress treatments. We theorize that the lower yields with the UAN treatment was a result of a greater portion of the commercial fertilizer nitrogen being lost to either denitrification or leaching than the manure nitrogen during that time period.

In the 2017 season the corn was originally planted on April 25. Emergence was so poor as to justify replanting, but field conditions were not firm enough to replant until June. The side-dress applications took place two weeks after planting as the corn grew rapidly with the warm temperatures.

The swine finishing manure application rate of 6,500 gallons per acre provided more than an adequate amount of nitrogen for the corn crop while being just short of balancing phosphorus for the two year needs of a corn-soybean rotation. The amount of potash applied with the manure was 24 pounds more than needed for the crop rotation.

The cost of purchasing 28 percent UAN fertilizer to side-dress corn averaged approximately 40 cents per pound during the four years of this study. At an application rate of 210 pounds per acre the commercial fertilizer side-dress cost was $84.00 per acre (210 pounds * $0.40 per pound). The landowner’s custom cost for applying liquid swine finishing manure was $8.00 per 1,000 gallons or $52.00 per acre (6,500 gallons at $8.00 per 1,000 gallons). The cooperating farmers in this study valued his corn at $3.40 and the 14.8 bushel advantage for the manure treated plots were valued at $50.32 per acre. He also did not need to purchase side-dress nitrogen for the acres where manure was applied, and this saved an additional $84.00 per acre.

Future plans

In this study the application of liquid swine finishing manure at side-dress produced higher corn yields, compared to commercial fertilizer, in three of the four study years. Incorporating liquid swine finishing manure as a side-dress nitrogen source to emerged corn can boost yields, reduce nutrient losses, and give livestock producers another window of time to apply manure to farm fields in-season. The money saved on purchasing commercial side-dress nitrogen can pay for the cost of the manure application to an emerged corn crop.

Ohio State University extension now owns three 12-row manure side-dress toolbars which are being loaned to livestock producers and commercial manure applicators for their use to side-dress emerged corn. We discovered that very few commercial manure applicators in Ohio currently have row-ready tractors and only a small percentage of livestock producers have large enough tractors to pull the drag hoses. Grant monies have also been secured to provide tractors to pull the sidedress toolbars.

There is strong interest from commercial manure applicators to apply manure to corn fields. This practice enables them to apply more total gallons of manure in a year. Current indications are that the application of manure to corn fields will continue to expand in the years ahead as commercial applicators gear up for this practice. Every gallon of manure applied to a growing corn crop in early June is one less gallon likely to be applied during the fall application window.

Authors

Arnold, G. , Field Specialists, Manure Nutrient Management Application, Ohio State University Extension. arnold.2@osu.edu
Custer, S., County Extension Educator, Darke County, Ohio State University

Additional information

Arnold, G. J. (2015). Corn yield results from side-dressing with liquid livestock manure. Journal of the NACAA, 8(2). Retrieved from https://www.nacaa.com/journal/index.php?jid=329

Sundermeier, A. (2010). Nutrient management with cover crops. Journal of the NACAA, 3(1). Retrieved from https://www.nacaa.com/journal/index.php?jid=45

Vitosh, M. L., Johnson, J. W., & Mengel, D. B. (2003). Tri-state Fertilizer Recommendations for Corn, Soybeans, Wheat and Alfalfa. Purdue Extension, Lafayette, IN.

Zhang, W., Wilson, R. S., Burnett, E., Irwin, E. G., & Martin, J. F. (2016). What motivates farmers to apply phosphorus at the “right” time? Survey evidence from the Western Lake Erie Basin. Journal of Great Lakes Research, 42(6), 1343–1356. https://doi.org/10.1016/j.jglr.2016.08.007

Facebook Page: Ohio State University Environmental and Manure Management

Ohio State University Extension Nutrient Stewardship YouTube: https://www.youtube.com/channel/UC7jUsQNGM8fCHjbZUdT9pKw

Acknowledgements

Thanks to Harrod Farms of Rossburg, Ohio for working with Ohio State University Extension on this research project

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2019. Title of presentation. Waste to Worth. Minneapolis, MN. April 22-26, 2019. URL of this page. Accessed on: today’s date.

April 30, 2019October 22, 2019

Feasibility of Reducing a Dairy Farm’s Manure Enterprise Costs Using a Wet Gasification Technology

Manure management is a major system on dairy farms, and there is a goal to minimize costs and maximize benefits. Technology that would reduce the mass of the manure to be spread, produce energy and a potential by-product for off-farm sales is needed. Adding wet gasification technology to existing manure systems with the goals of reduced spreading costs and possibly increased by-product sales was evaluated on a central New York farm that was considering expanding. For expansion to be possible, additional cropland was needed to recycle the additional manure at a further distance from the farmstead. An economic analysis examining the potential impact the wet gasification technology would have on the farm was conducted and results were shared with the dairy producer for use in making informed decisions.

What did we do?

A wet gasification technology that was presented by the manufacturer to be able to extract energy from manure solids (also reducing mass) was evaluated to determine the potential as an improvement to the farm’s existing manure management system. Application of this technology on an example farm was investigated to see what the applications might be on the existing farm (1,500 cows and 1,590 acres) and when expanded to 2,500 cows with 2,990 acres of cropland. Current and projected farm data along with cost and performance data from the manufacturer of the gasification system were used to perform an annual economic cost-benefit analysis as a way to determine the value of the system to the farm’s manure management enterprise.

Figure 1. Example Mass and Energy Flows for a Wet Gasification System

What have we learned?

There are many variables to consider, and the results of the sensitivity analysis show that the variables that influence the outcome of the total annual economic cost-benefit analysis are the ones least under the control of the technology provider or farm (capital cost, lost capital rate, milk production change due to bedding use change, nitrogen value of fertilizer, price of electricity, and value of the ash). Annual spreading costs at the time of analysis ranged from $36/acre for close fields with a low amount of manure spread, to $256/acre for further fields spread at a high amount of manure.

For the case farm analyzed, the system economics would only be favorable if optimistic values were assumed for some of the predictor variables such as high prices for the ash by-product and/or higher prices for the excess energy produced. Raw dairy manure’s moisture content is too high for efficient gasification. Wet gasification is better suited to operations where the raw manure has lower moisture content (due to substantial bedding use) or can be pre-processed to obtain a very dilute liquid stream (that can be spray irrigated) and a solid product, having 25-30% solids, that could be processed by gasification to produce a salable ash. The values for byproducts, energy and nutrients from manure, need to be large enough to support a manure treatment system. Dairy farms need to consider the impact of a manure treatment technology on the whole farm system.

Prices to obtain a zero economic benefit (net benefits minus costs equal $0) for the expanded 2,500-cow dairy in central NY for each variable alone.
Variable	Break-Even Price	Comments
Capital costs ($/Unit)	$0 Wet Gasification $0 for SLS $1,750/kW for steam gen set	Assuming grants are available Assuming a separator already exists Steam gen-set is $1,750/kW
Electric Price ($/kWh)	$0.156/kWh 5M kWh/yr. produced	Includes $0.03/kWh maintenance cost on engine generators. (This is renewable energy but only ~50% reduction in GHG
Hauling cost ($/load)	$2,530/load 159 loads/yr. reduced	8,400 gallons/load (approximately a 420-mile round trip)
Ash Sales ($/ton)	$374/ton 898 tons/yr. produced	This price includes the reduced hauling costs as the water separated from the ash can be spray irrigated without hauling.

Future Plans

We continue to evaluate manure treatment systems that have the potential to reduce the mass of the manure to be spread, produce energy, partition the nutrients, reduce greenhouse gas emissions, and a produce a potential by-product for off-farm sales and extending this knowledge to dairy operators.

Corresponding author, title, and affiliation

Peter Wright, Agricultural Engineer, Dept. of Animal Science, Cornell University

Pew2@cornell.edu

Other authors

Curt Gooch, Senior Extension Associate at Cornell University, Dept. of Animal Science, PRO-DAIRY

Additional information

Additional project information can be found on the dairy environmental system webpage: www.manuremanagement.cornell.edu.

Acknowledgements

The farm and the wet gasification technology company provided the needed data to make the economic analysis. Funding for this project was supported by Cornell’s Jumpstart program.

April 18, 2019October 22, 2019

Aeration for Elimination of Manure Odor and Manure Runoff: What One Professional Engineer Has Learned in the Past 12 Years

Aerobic treatment has potential to be more practical for any size operation, reduce odors, reduce risk of runoff by facilitating application to growing crops, and reduce energy use when distributing manure nutrients.

Farm-based aeration, created through an upward/outward surface flow, was first introduced in the 1970’s and brought partial success. With significant performance issues, challenges with struvite within manure recycling pipes/pumps, and the growing trend to store manure within pits under barns, further research with manure aeration was largely abandoned. Very little research has been done on aerobic treatment within manure storage systems since traditional aeration using air blowers has been considered too expensive. Previous research sought to mimic traditional domestic wastewater treatment systems which also purposely perform denitrification. Not always a goal for farm operations in years past, retaining Nitrogen within wastes used as fertilizer is now usually a goal. Thus, past aerobic treatment systems were not designed to fully benefit today’s modern farms.

In 2006, hog producers were introduced to an updated version of equipment providing Widespreading Induced Surface Exchange (WISE) aeration, specifically for reducing hog manure odor while irrigating lagoon effluent. The results became a “wonder” for the site’s CAFO permit engineer. Documentation showed that significant aeration was occurring at a rate much higher than could occur with the energy input used by traditional bubble blowers. This indicated that aeration of manure ponds and lagoons may not be too expensive after all. More questions led to a USDA NRCS-supported study, which revealed much more information and brought out more questions. The final report of that study is available at http://pondlift.com/more-info/, along with other information on the technologies described.

The NRCS-funded study revealed the basis for previous performance failures, while it also showed the basis for getting positive aeration performance at liquid manure storage sites: Ultimately, this information showed that large reductions of manure odor can be obtained while offering a new paradigm for eliminating most potential manure runoff through WISE aeration as the first step.

The paradigm change summary:

Aeration provides aerobic bacteria based manure decomposition while in storage.
Aerobic bacteria produce only carbon dioxide, which is considered carbon neutral when converting manure’s nutrients to fertilizer, reduced greenhouse gas (Aerobic gives off no other greenhouse gasses such as methane or oxides, and few odors)
“No odor” allows direct distribution of decomposed manure nutrients onto crops during growing season. (Distribution is done during growing season, using automated irrigation equipment).
Low-cost automated manure distribution reduces farm operation costs, but also allows the nutrients to be distributed to equal acres during a wider application time frame (not limited to when crop land is barren in spring or before fall freezeup.)
A wider application time frame allows multiple applications at smaller doses onto growing crops. Depending on nutrient application goals and equipment, irrigation rates can be as little as 1/8^th inch of water, multiple times through the year, instead of one large dose.
Irrigation equipment is likely not operating when potential runoff conditions are pending, especially when the entire spring/summer/fall periods are available for distribution.
When nutrients are applied onto growing crops at low dosage rates during periods when irrigation is desired, very little potential for runoff is present. Only a small portion of 1/8” of water onto a crop canopy rarely reaches the ground. The nutrient rich water quickly binds with the dry surface soil when it does get past the crop canopy during summer application.
Current manure distribution distribution requires that most farmers fight to get raw manure distributed onto cropland before spring planting (which is often a wet time of year), OR after crops are harvested and bales removed. Although farmers and regulators wish that all manure handling is performed before freezeup, it is not the case: It happens more than anyone admits. Manure application to frozen ground is an understated and unquantified manure runoff cause. Such runoff can be eliminated by the new paradigm of application onto growing crops.

Further, the “side use” of treated effluent has significant benefit compared to raw manure. Aerobic Bacteria-Laden Effluent (ABLE water) is extremely proficient in its use within flume systems and for automatic flushing of alleys. The aerobic bacteria within the treated water is “hungry” to go to work, to pick up fresh food as it passes over the floor/alley, on its way back to the storage pond.

The layman’s explanation is similar to urban water delivery pipes and wastewater pipes buried within city streets:

Historically, dairy operators quickly learned that fresh well water will create a “slime” on surfaces, causing extremely slippery floors and alleys which injure cows. To eliminate much of the slipperiness, they stopped using fresh water and instead used raw manure from the pond. In many cases, they would add water to the pond, when manure got too thick and again caused slippery areas.
Unseen by most people are the 2 pipe systems under streets carrying our water and sewer. Factually, one pipe has slime, and the other pipe is amazingly clean: While acknowledging the newspaper notices that fire hydrants are going to be “flushed” several times/year, most don’t realize the purpose for doing so is to flush the slime from our drinking water pipes! The slime is not toxic to humans due to chlorination, but its buildup reduces pipe capacity, and its color is unpleasant to see in drinking water. In the case of unaerated fresh water used at farms, it tends to grow the slime that dairymen simply can’t afford on their alleys/floors.
Meanwhile, most people won’t look into a sewer manhole to note how “clean as a dinner plate” it looks! Sewerage pipes are designed for high capacity peak flow but normally runn at very low levels. This allows tremendous aeration activity within the system as water tumbles at manholes and as flows change direction. Thus, the aeration, food, and bacteria within properly operating sewer systems have very little odor, with the bacteria laden effluent continuously cleaning the sewer pipe. Sewer Pipes indeed look “brand new” even after operating for decades! Those who effectively aerate their manure pond water so they have high aerobic populations within the effluent, and use that effluent for flushing alleys and flumes are quite happy with the resultant cleaning of the alleys, floors, and flumes.

Lastly, ABLE water likely has traits of “compost tea”: Compost Tea is made by steeping in water, a quantity of completed compost, rich with soluble nutrients, bacteria, fungi, protozoa, nematodes and microarthropods. After removing the steeped compost solids, the remaining effluent is rich with those items recognized by many as necessary for building the soil and most effective for plant growth. The tea is to be used quite soon after it is created, but aeration can lengthen the storage period. Within aerobically treated manure ponds, because aeration is being performed continuously, compost tea-like benefits are anticipated to be included to crops having the WISE treated effluent application.

What did we do?

A basic hypothesis for WISE technology was developed in 2014 to explain why aeration levels are significantly higher compared to bubble blower technology. This hypothesis explains how/why results are being obtained and allows purposeful thought on how to maximize performance.

Meanwhile, engineering solutions were developed for the two main issues of equipment available at the time: 1) Previous equipment was heavy and required boom trucks/cranes to install/remove it for servicing (250 to 900 lb.), and 2) The propeller orientation/shape would inherently draw in stringy material that wraps on the propeller shaft, which then requires removal (see problem 1). New equipment was designed that weighs less than 120 lb. and is easily installed by hand (Figure 1).

Figure 1. One of two WISE technology models, this for open ponds (44” wide). The other model fits through a doorway to be installed in the manure storage pits of deep-pit hog barns.

What have we learned?

After years of testing the new design, the equipment proved to be able to operate without inviting stringy material to wrap on the propeller and to be easy to handle by hand. The design was declared an engineering success and marketing began.

In addition, nitrogen retention rates for aerobic manure treatment are much higher than published, most likely due to the traditional domestic wastewater treatment process assumptions of the 1970’s and the use of partial aeration, due to high costs of bubble blowers, instead of continuous aeration used within WISE aeration activity.

Prior to the 2018 North American Manure Expo, data was collected at 3 different farms in the Brooking SD area, each farm having a different brand/style of providing aeration. Due to the uncontrolled variables, results varied within each farm and also varied from the other farms. Although no clear specific results were determined, one specific trend was that installing equipment at a higher operational rate (1 device/50 animal units) than the study used (1 device/70animal units), offered higher nitrogen retention than can be expected from the NRCS funded study, which is higher than currently published aeration rates. This leads me to believe that there may be some misunderstood biological process for retaining nitrogen within aerobically treated effluent using WISE aeration. It appears there are some things unequivocally misunderstood about aerobic manure treatment and the nutrients retained, most likely also associated with the items commonly identified/targeted with Compost Tea discussions. The potential for changing the current manure handling paradigm to one where odor is not an issue, and application of manure nutrients onto growing crops which might also reduce manure runoff warrants further study.

The presentation will also touch on some basic misunderstandings about ammonia/ammonium, provide “do’s” and “don’ts” of installations and/or studies, and identify additional subjects for study.

What are the next steps?

Associated technology is being developed to perform foliar application. If farmers can’t handle manure differently, why would they do additional work, just to distribute it the same way they do now? The presentation will include basic information for a Self-Propelled Extremely Wide Portable Linear Irrigator (SPEWPLI). This equipment is projected to be able to irrigate/fertigate a full 160-acre field in 5 passes, and then be quickly moved to the next field. It is anticipated that manure pumpers would use existing equipment to deliver liquid manure to fields and use the SPEWPLI equipment as an alternative to conventional drag-hose injection. Foliar feeding has proven beneficial, applying nutrients directly onto growing crops (in canopy) when they best increase yields. By changing the distribution window to summertime, farmers don’t need to apply only in spring or in fall, or leave fields un-planted so manure can be applied in the summer.

While most farmers will not spend money to buy technology which only rids manure of odor while they continue to handle it as they have in the past, since there is very little economic return for only controlling odor, there are other aspects of WISE aeration technology to provide economic return, which then provides odor relief as a “free” benefit.

More information is needed on the benefits of distributing manure nutrients directly to growing crops and on the economics of low-cost, automated systems.
More information is needed in maximizing aeration for the energy used by way of this technology.
More information is needed in how nitrogen can possibly be tied up and reserved by the other bacteria, fungi, protozoa, nematodes and microarthropods within compost tea-like effluent.

A listing of such subject study items, likely to be doctorate dissertation level projects, will be included in the presentation.

Because our brand resolves issues that other equipment has, we will make it available for academic study at field sites and for others to use for additional research in the use of WISE aeration technology.

Author

John Ries, PE, Pond Lift, Elk Point, SD, johnries@pondlift.com

April 11, 2019June 24, 2019

New Technologies to Help Us Share Stories and Ideas

This two-part workshop exposes participants to a wide variety of existing and new technology, and how these applications can enhance learning and programming.

During each part of the session, there will be a series of short presentations, opportunity for sharing of ideas, followed by time to ask questions and try the tech at tables around the room.

Session moderated by Alison Holland, University of Minnesota Extension

Part 1: Bringing Science to Life Through Immersive Imagery and 3-D Modeling

<span style="display: inline-block; width: 0px; overflow: hidden; line-height: 0;" data-mce-type="bookmark" class="mce_SELRES_start"></span>Megan Weber and Angela Gupta, University of Minnesota Extension

Lecture-free, interactive online course

3D IS models

Augmented reality in IS

360-imagery

Part 2: New Education and Engagement Strategies with Familiar Tech Tools

Pollinator Qualtrics Survey

Julie Weisenhorn, University of Minnesota Extension

Qualtrics: Not Just for Surveys Anymore! Create Online Modules & Learning Centers

Abby Neu, University of Minnesota Extension

Mapping for Teaching and Showing Program Impact

Alison Holland, University of Minnesota Extension

April 7, 2019October 22, 2019

Versatility of the MAnure PHosphorus EXtraction (MAPHEX) System in Removing Phosphorus, Odor, Microbes, and Alkalinity from Dairy Manures

Animal manures contain nutrients [primarily nitrogen (N) and phosphorus (P)] and organic material that are beneficial to crops. Unfortunately, for economic and logistics reasons, dairy manure tends to be applied to soils near where it is generated. Over time P concentrations in soils where dairy manure is applied builds up, and is often in excess of crop demands. We previously described, and have subsequently built, a full-scale version of a MAnure PHosphorus EXtraction (MAPHEX) System capable of removing greater than 90 percent of the P from manures. While originally designed to remove phosphorus, we postulated that the MAPHEX System was also capable of removing odor and microbes, and of concentrating alkalinity into a solid, economically transported form. In this study the MAPHEX System was shown to be highly versatile at removing greater than 90 % of the phosphorus from a wide range of dairy manures. In addition to that, the study showed that the System is also capable of concentrating and recovering alkalinity from manures, while also removing over 80 % of microbes and reducing the odor of the effluent applied to fields by half. We have also lowered daily operating costs by testing the effect of lower-cost chemicals as alternatives to ferric sulfate, and by showing that the diatomaceous earth (DE) filtering material can be recycled and reused.

Corresponding author

Clinton Church (USDA-ARS)

Clinton.Church@ars.usda.gov

Other authors

Kleinman, Peter (USDA-ARS); Hristov, Alex (Pennsylvania State University); Bryant, Ray (USDA-ARS)

April 7, 2019April 2, 2021

Performance and Payback of a Solid-Liquid Separation Finishing Barn

A 1200-hd solid-liquid separation finishing barn was built in Missouri for improved manure management and air quality. The facility has a wide V-shaped gutter below slatted flooring (Figure 1), which continuously drains away liquids. A scraper is used to collect the solids, which are then managed separately. Field sampling and research were conducted to evaluate the performance of the solid-liquid separation finishing barn in improving manure nutrient management, potential nutrient/water recycling based on filtration, and barn construction and operating costs.

What did we do?

The barn (built in 2010) was closely monitored for manure production and nutrient content, and operating costs. Laboratory-scale pretreatments and filtrations were conducted to evaluate the practicality of nutrient/water recycling from the separated liquid manure.

What we have learned?

The daily liquid manure production averaged 885 gallons and daily solid manure production averaged 299 gallons (about ¼ of the total manure volume). The separation system removed 61.7%, 41.7%, 74.8%, and 46.2% of the total manure nitrogen, ammonium, phosphorous, and potassium, respectively, with the collected solids. The filtration results indicate that the microfiltration and reverse osmosis were time and energy intensive, which was probably constrained by the relatively small-scale unit (inefficient compared with larger units), small filter surface area, and high concentration of dissolved nutrients.

The construction cost of the solid-liquid separation barn with solid manure storage was $323,000 ($269/pig-space, in 2010), 17% higher compared to the traditional deep-pit barn ($175 to $230/pig-space). It is likely that the solid-liquid separation barn will become less expensive when more barns of similar design are built, and the conveyor system can be improved and simplified for less maintenance and lower costs. Additional electricity cost was $331 per year for daily operation of the scraper and conveyor systems, and pumping the separated liquid manure fraction. The additional maintenance cost of the scraper system averaged $1,673/year. A net gain of $3,975/year was observed when considering the value of the separated manures, cost of land application, and annual maintenance cost.

A payback period of 15.1 years on the additional investment was estimated, when compared with the popular deep-pit operation. However, the payback period can be reduced by many factors, including improved conveyor system and growing popularity of the barn design in an area. When the distance to transport the slurry manure was increased from 5 miles to 7.5 and 10 miles, the payback periods became 12.7 and 11.3 years, respectively. The solid-liquid separation barn was shown to have better air quality when compared with deep-pit barns based on monthly measurements of ammonia and hydrogen sulfide concentrations.

Impacts/Implications of the Research.

This study monitored the manure production of a commercial finishing barn utilizing a solid-liquid separation system. Overall, we can conclude that the final results obtained from monitoring the total manure production rate, air quality exiting the barn fans, and the pig growth rates made sense relative to other comparative sources. The overall results indicate that the barn design can attain some valuable benefits from separating the solid and liquid streams. About a quarter of the manure volume was collected and managed as nutrient-dense solid manure (defined as ‘stackable’). The solid manure held 80% of the total solids and nearly 75% of the phosphorous.

Take Home Message

There are alternative barn designs and manure management systems (relative to lagoon and deep-pit operations) that should be considered when planning for a new operation or expansion. Considerations should include the need to better manage manure nutrients and improve air quality for human and animal occupants.

Future plans

Further consideration of the manure management, including work load and major- and micro-nutrients need to be furthered analyzed. Future research may look into application of a larger-scale crossflow system to see if nutrient removal and flow rates can be improved significantly. Future research may focus on improving manure filtrate flow, and determining the cost of installation and upkeep for a filtration unit that can operate at the level of a farm operation. Extrapolating the costs off of bench-scale model does not seem remotely indicative of the true cost, due to improved efficiency and power of larger unit.

Authors

Lim, Teng (Associate Professor and Extension Agricultural Engineer, Agricultural Systems Management, University of Missouri, limt@missouri.edu)

Brown, Joshua (University of Missouri); Zulovich, Joseph (University of Missouri); and Massey, Ray (University of Missouri).

Additional information

Please visit https://www.pork.org/research/sustainability-evaluation-solid-liquid-manure-separation-operation/ for the final report, and ASABE Paper No. 1801273 (St. Joseph, Mich.: ASABE. DOI: https://doi.org/10.13031/aim.201701558) for more information.

Acknowledgements

Funding for this research project was provided by the National Pork Checkoff and University of Missouri Extension.

Figure 1. The V-shape pit with automated manure scraper and trough at center (Left), and gravity draining of liquid manure from the trough to the sump pit (Right).

Figure 2. The storage shed for solid manure to the north of the modified scraper barn (Left), and stored solid manure (Right).

April 7, 2019October 22, 2019

Overview of the U.S. Agricultural Biogas Industry and AgSTAR Technical Resources

AgSTAR is a voluntary program coordinated by the U.S. Environmental Protection Agency (EPA), in cooperation with the U.S. Department of Agriculture (USDA), that supports farmers and industry in the development and adoption of anaerobic digester (AD) systems. In addition to producing biogas, AD systems can help achieve other social, environmental, agricultural and economic benefits. AgSTAR offers a variety of resources and tools to assist those interested in exploring the use of AD systems, including:

- Outreach materials addressing system design, selection, and use and project development tools that help assess digester feasibility.
- Events including workshops and webinars to promote sharing of knowledge, information, and experiences.
- Website information on operating digesters, including nationwide statistics as well as in-depth project profiles that provide details on digester system design, biogas use, and benefits realized.

AgSTAR’s presentation will provide a market overview of agricultural biogas projects in the United States, including trends and outlook for the future of this sector, and highlight two resources currently under development for industry stakeholders.

What did we do?

AgSTAR’s mission is to educate and inform stakeholders on biogas production in the United States and support the development of new projects. AgSTAR has developed a number of market studies, technical tools and outreach resources for agricultural biogas projects over the years. The AgSTAR national database for digester projects contains a wealth of information on digester projects in the United States. As of January 2019, there are 248 anaerobic digesters operating on livestock farms in the US. AgSTAR estimates that in 2018, digesters helped reduce 4.27 million metric tons of CO₂ equivalent (MMTCO₂e). Since 2000, digesters on livestock farms have reduced direct and indirect emissions by an estimated 39.3 MMTCO2e.

The biogas industry in the livestock sector has a lot of room to grow. AgSTAR estimates that biogas recovery systems are technically feasible at more than 8,000 large dairy and hog operations. These farms could potentially generate nearly 16 million megawatt-hours (MWh) of energy per year and displace about 2,010 megawatts (MWs) of fossil fuel-fired generation.

To meet this massive opportunity, innovation is needed. Several policies and business models that are driving the growth in this sector include:

- Policies:

- - Food Waste Diversion from Landfills
  - Renewable Natural Gas (RNG) Incentives

- Business Models:
  - RNG to vehicle fuel
  - Third-party owned and operated systems
  - Eco-markets for co-products

AgSTAR continues to educate stakeholders on these industry trends and encourage new opportunities.

New and Updated products coming soon!

The AgSTAR program pleased to announce two resources coming in 2019 to help facilitate the implementation of AD-biogas projects:

- AgSTAR Project Development Handbook (3rd Edition) – The Handbook is intended for agriculture and livestock producers, farm owners, developers, investors, policymakers, implementers, and others working in agriculture or renewable energy who are interested in AD/biogas systems as a farm manure management option. The handbook is being substantially redesigned for this 3rd edition to help users gain insight into AD and current state-of-the-art discussions on project development, economics, co-digestion feedstocks, manure management issues, including agronomic application, potential carbon impacts, and financing/operational/ownership options. The document provides basic information about biogas production and outlines many of the considerations and questions that should be addressed when evaluating, developing, designing and implementing a farm-based digester project.
- AgSTAR Anaerobic Digester Operator Guidebook – The Operator Guidebook is a new resource to assist on-farm AD/biogas system operators to increase operational uptime and performance and efficiency as well as to help prevent common pitfalls that can lead to system shutdown and neighbor complaints. The Guidebook spans nearly every part of the AD and biogas production process, providing industry expert experience and advice on dealing with potential issues within an AD/biogas system. The Guidebook is designed to answer fundamental questions about what it takes to successfully operate and maintain an AD/biogas system on an agricultural operation and it can be used as a resource to maximize profitability by increasing biogas yield, improve biogas quality, and minimize operating and maintenance expenses. It is intended for use as a training tool for AD/biogas system owners, managers, operators, and other project stakeholders.

What we have learned?

Anaerobic digesters on livestock farms can provide many benefits compared to traditional manure management systems, including:

- Diversified Farm Revenue
- Rural Economic Growth
- Conservation of Agricultural Land
- Energy Independence
- Sustainable Food Production
- Farm-Community Relationships

While technology choices are important when implementing AD projects, a viable business model is critical.

Future plans

The AgSTAR Program intends to continue working with its government, academia, industry, and non-profit organization stakeholders to promote the use of biogas recovery systems to reduce methane emissions from livestock waste. This includes sharing information on industry trends; promoting and conducting events and webinars; and preparing outreach materials and project development tools, such as the AgSTAR Project Development Handbook and Anaerobic Digester Operator Guidebook.

Authors

Nick Elger, Program Manager, U.S. EPA AgSTAR & Global Methane Initiative, Elger.Nicholas@epa.gov

Additional information

Additional information and resources can be found on the AgSTAR Program website at: https://www.epa.gov/agstar.

April 7, 2019October 22, 2019

The Use of USDA-NRCS Conservation Innovation Grants to Advance Air Quality Improvements

USDA-NRCS has nearly fifteen years of Conservation Innovation Grant project experience, and several of these projects have provided a means to learn more about various techniques for addressing air emissions from animal agriculture. The overall goal of the Conservation Innovation Grant program is to provide an avenue for the on-farm demonstration of tools and technologies that have shown promise in a research setting and to further determine the parameters that may enable these promising tools and technologies to be implemented on-farm through USDA-NRCS conservation programs.

What Did We Do?

Several queries for both National Competition and State Competition projects in the USDA-NRCS Conservation Innovation Grant Project Search Tool (https://www.nrcs.usda.gov/wps/portal/nrcs/ciglanding/national/programs/financial/cig/cigsearch/) were conducted using the General Text Search feature for keywords such as “air”, “ammonia”, “animal”, “beef”, “carbon”, “dairy”, “digester”, “digestion”, “livestock”, “manure”, “poultry”, and “swine” in order to try and capture all of the animal air quality-related Conservation Innovation Grant projects. This approach obviously identified many projects that might be related to one or more of the search words, but were not directly related to animal air quality. Further manual review of the identified projects was conducted to identify those that specifically had some association with animal air quality.

What Have We Learned?

Out of nearly 1,300 total Conservation Innovation Grant projects, just under 50 were identified as having a direct relevance to animal air quality in some way. These projects represent a USDA-NRCS investment of just under $20 million. Because each project required at least a 50% match by the grantee, the USDA-NRCS Conservation Innovation Grant program has represented a total investment of approximately $40 million over the past 15 years in demonstrating tools and technologies for addressing air emissions from animal agriculture.

The technologies that have been attempted to be demonstrated in the animal air quality-related Conservation Innovation Grant projects have included various feed management strategies, approaches for reducing emissions from animal pens and housing, and an approach to mortality management. However, the vast majority of animal air quality-related Conservation Innovation Grant projects have focused on air emissions from manure management – primarily looking at anaerobic digestion technologies – and land application of manure. Two projects also developed and enhanced an online tool for assessing livestock and poultry operations for opportunities to address various air emissions.

Future Plans

The 2018 Farm Bill re-authorized the Conservation Innovation Grant Program through 2023 at $25 million per year and allows for on-farm conservation innovation trials. It is anticipated that additional air quality projects will be funded under the current Farm Bill authorization.

Authors

Greg Zwicke, Air Quality Engineer, USDA-NRCS National Air Quality and Atmospheric Change Technology Development Team

greg.zwicke@ftc.usda.gov

Additional Information

More information about the USDA-NRCS Conservation Innovation Grants program is available on the Conservation Innovation Grants website (https://www.nrcs.usda.gov/wps/portal/nrcs/main/national/programs/financial/cig/), including application information and materials, resources for grantees, success stories, and a project search tool.

April 4, 2019July 23, 2021

Considerations in Evaluating Manure Treatment Systems for Dairy Farms

Advanced manure treatment may become a major system on some dairy farms in the future. Reducing the impacts of excess nitrogen and or phosphorous may be necessary on farms with a limited or remote land base. Additional treatments to recover solids, extract energy, concentrate nutrients, reduce odors, reduce the mass/volume, and/or reduce pathogens may become more of a priority as farms seek to move toward sustainability. Potential systems should be evaluated from many perspectives including on an economic and effectiveness basis. There are many variables to consider in evaluating a manure management system. Potential systems should be selected based on many criteria including: operational history, operational reliability, market penetration, capital cost, O&M cost, value proposition, and vendor information and documentation including case studies and customer reviews.

What did we do?

Manure management formally started in the second half of the 20th century with the development and implementation of the water quality best management practice (BMP) of long-term manure storage. Storage provides farms with the opportunity to recycle manure to cropland when applied nutrients can be more efficiently used by the crop. Many long-term manure storages were built to improve nutrient recycling and minimize risk. In some cases, anaerobic lagoons were built to both reduce the organic matter spread to fields and store manure. Simultaneously as poultry and livestock consolidation escalated, more manure storages were built and their volume increased to reflect the recognized need to store manure longer. Cooperative Extension, Soil and Water Conservation Districts and Natural Resources Conservation Service have assisted in providing planning, design, construction and maintenance of these manure storage systems.

What have we learned?

Many lessons have been learned from storing manure long-term. They include, but are not limited to:

- While storing manure long-term reduces water quality impairment, it also produces and emits methane, a greenhouse gas. Greenhouse gases are reported to contribute to global warming. The US dairy industry is under attack by some because of this, and it is likely that the decline in fluid milk sales has, in some part, been affected by this. The lesson learned here is that the implementation of BMPs can have unintended consequences; therefore, all future BMPs need to be thoroughly vetted before substantial industry uptake happens in order to avoid undesirable unintended consequences.
- Larger long-term storages are better than short-term (smaller) ones. Storages that store manure for a longer period of time provide farms with increased flexibility when it comes to recycling manure to cropland.
- Long-term storages can emit odors that can be offensive to neighbors and communities. Farms have adopted improved manure spreading practices, namely direct incorporation, to reduce odor issues but incorporation doesn’t work well on some crops. Some farms have also adopted anaerobic digestion as a long-term storage pre-treatment step in order to reduce odor emissions from storage and land application.
- Substantial precipitation can accumulate in long-term storages located on farms in humid climates. Increased storage surface area (generally an outcome of building larger storages) results in more precipitation to store and handle as part of the manure slurry. Every acre-foot of net perception results in 325,900 gallons of additional slurry to store and spread. If each manure spreader load is 5,000 gallons, then this means 65 additional loads are required.
- Neighbors of larger farms are more sensitive to intensive truck traffic than regular but low-level truck traffic. Long-term storages require intensive, focused effort to empty and the over the road truck traffic can be offensive in some farm locations.
- Insufficient storage duration results in the need to recycle manure to cropland during inopportune times and thus may not be contributing to the BMP goal. Fall spreading is still required on many farms; however, it also may be unlikely that a sufficient spring planting window exists for farms to spread all their manure in the spring, avoid compacting wet soils and also get spring crops planted in time.
- Where longer term storage duration and or incorporation of the manure to prevent odor emissions is needed to facilitate spring and summer manure spreading, farms may have more manure nutrients than needed to meet crop demand.

Future Plans

The above lessons learned support the need for advanced manure treatment systems on some farms that can also be used as the basis for considerations that should be included when evaluating all manure treatment systems. It is important that the manure treatment equipment/system components and the overall system address the farm need(s) as best as possible. A challenge with evaluating the existing manure treatment equipment available to the farmer is the lack of performance and economic data. Comparatively, advanced manure treatment (we define this as treatment above basic primary solid-liquid separation) is in its infancy stage of adoption and thus little field performance data exists. Our plans are to continue (as funding allows) to perform more on-farm manure treatment system evaluations and to report facts to our US dairy industry stakeholders.

Corresponding author, title, and affiliation

Curt Gooch, Environmental Systems Engineer, PRO-DAIRY Dairy Environmental System Program, Dept. of Animal Science, Cornell University

cag26@cornell.edu

Other authors

Peter Wright, Agricultural Engineer, PRO-DAIRY Dairy Environmental System Program, Dept. of Animal Science, Cornell University

Additional information

Additional project information, including reports about on-farm assessment of manure treatment systems, is available on the Dairy Environmental System Program webpage: www.manuremanagement.cornell.edu

Acknowledgements

New York State Department of Agriculture and Markets for their continued financial support of the PRO-DAIRY Program, the New York State Energy Research and Development Authority (NYSERDA) for funding many on-farm sponsored projects, and the US dairy farmers who have collaborated with us for over three decades.

April 4, 2019October 22, 2019

NRCS Solid-Liquid Separation Document – It is Finally Here!!

NRCS has a new technical document entitled “Solid-Liquid Separation Alternatives for Manure Handling and Treatment.” It was created through efforts from Dr. John Chastain, Clemson University with funding provided by USDA-NRCS.

Screw press solid-liquid separator (Source: USDA-NRCS)

This document brings together both the theory behind solid-liquid separation and the practical application of many different separation technologies. Several farm scale demonstration projects are also summarized in the report. Solid-liquid separation can serve to achieve many livestock operational objectives such as nutrient partitioning, improved pumping characteristics, solids removal from storage facilities and reduced organic loadings. The use of separation technologies is essential for many operations and has become an integral part of the efficient performance of these livestock facilities. Some of the purposes and uses of this document include assisting in solid-liquid separation technology selection, evaluating separation performance, and quantifying the impact of solid-liquid separation on manure management. This presentation provides an overview of this document including methods of solid-liquid separation, influence of manure characteristics and handling methods, fundamentals of solid-liquid separation, performance of various solid-liquid separation technologies, unique separation technologies and applications and design considerations.

What Did We Do?

Use of coagulant and flocculant to enhance solid-liquid separation (Source: USDA-NRCS)

Extensive effort through literature searches and testing went into compiling performance and design information on various types of solid-liquid separation technologies. Separation theory was incorporated into the document to provide an understanding of separation principles and background information to assist in technology selection for improved system performance. To improve usability of the document, it was divided into the following chapters: Methods of Solid-Liquid Separation, Manure Characteristics and Handling Methods, Fundamentals of Solid-Liquid Separation, Measures of Solid-Liquid Separation Performance, High-Rate Solid-Liquid Separation, Unique Applications of Solid-Liquid Separation Technology, and Design Considerations. Several examples were provided throughout to assist in the design process of the various technologies. The document also includes information on the uses and benefits of coagulants and flocculants and separation methods associated with sand laden manure. Numerous system diagrams assist in illustrating the vast array of solid-liquid separation technologies that can be implemented in an animal manure treatment system.

What Have We Learned?

This work brings together fundamental information about solid-liquid separation, benefits and limitations of many separation technologies, performance measurement techniques along with design considerations into one document. Even though there are significant differences in performance and costs between the various separation technologies, the approach selected is largely dependent on critical elements such as landowner objectives, facility size, performance goals, operation and maintenance and other factors. This document will help designers and operators choose the separation technology or technologies that will best meet the goals established for the operation.

Future Plans

This document will be published as chapter 4 of the USDA-NRCS National Engineering Handbook, Part 637 Environmental Engineering.

Author

Jeffrey P. Porter, P.E.

Animal Manure and Nutrient Management Team Leader

USDA-Natural Resources Conservation Service

jeffrey.porter@gnb.usda.gov

Additional information

Once published, a copy of the document can be found at https://directives.sc.egov.usda.gov/.

Acknowledgements

A special thank you goes out to the Piedmont-South Atlantic Coast Cooperative Ecosystems Studies Unit (CESU). This Cooperative and Joint Venture Agreement allowed for this work to be completed.

Additional support was provided by the Confined Animal Manure Managers Program, Clemson Extension, Clemson University, Clemson, SC.