Land Application of Accumulated Solids From Liquid Waste ... Application Report.pdf · Land...
Transcript of Land Application of Accumulated Solids From Liquid Waste ... Application Report.pdf · Land...
Final Report
Land Application of Accumulated Solids
From Liquid Waste Systems
Demonstration Project
E.P.A. 319(h) FY 1997 Project 700
Prepared and Submitted by the
Arkansas Department of Environmental Quality
Environmental Preservation Division
September 30, 2002
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Table of Contents I. Introduction ................................................................................................................................. 9
II. Background .............................................................................................................................. 11
III. Land Application Project Description and Implementation ................................................... 17
Pond Clean-Out and Land Application Planning...................................................................... 19
IV. Solids Clean-Out Plan Development Strategy ........................................................................ 21
Liquid Manure Characterization ............................................................................................... 21
Waste Management Plan Review ............................................................................................. 23
Plan Development ..................................................................................................................... 23
V. Project Results.......................................................................................................................... 27
Returning to Facilities After Clean-Out .................................................................................... 34
Analysis of manure samples ..................................................................................................... 34
VI. Clean-Out Case Study............................................................................................................. 37
Tank Spreader Sampling ........................................................................................................... 41
VII. Aluminum Chloride Demonstration and Economic Alternatives ......................................... 43
University of Arkansas Report on Alum Addition ................................................................... 44
VIII Conclusions ........................................................................................................................... 55
References ..................................................................................................................................... 59
List of Appendix
Appendix A. Power Point Presentation Slides Presented to Regulation No. 5 Attendees and to
Participating Conservation Districts
Appendix B. LAWMS Sampling Procedures and Sampling Data Collection Sheet
Appendix C. LAWMS Clean-Out Plan Check List
Appendix D. Manure Management Services
Appendix E. Clean-Out Plan Summary
Appendix F. Raw Data From Sample Analysis
Appendix G. Example of a Completed LAWMS Clean-Out Plan
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Table of Figures Figure 1. Typical Concentrations of Nutrients in Maintained and Non-Maintained LAWMS ... 12
Figure 2. Locations of Swine Facilities in Arkansas ................................................................... 14
Figure 3. Nutrient Concentration Differences in Maintained and Non-Maintained LAWMS .... 15
Figure 4. Collection of LAWMS Pond Samples ......................................................................... 21
Figure 5. LAWMS Pond Sample Collection Methodology ......................................................... 22
Figure 6. High STP Adjacent to Facility ..................................................................................... 24
Figure 7. Locations of Participating Facilities ............................................................................. 27
Figure 8. Nutrient Concentrations in Holding Ponds Prior to and Following Annual Manure
Solids Removal ......................................................................................................................... 34
Figure 9. Concentration of Nutrients Found in Various Phases of LAWMS Manure Storage ... 34
Figure 10. Concentration of Analytes in Composite Samples Collected From Holding Ponds .. 35
Figure 11. Concentration of Analytes in Accumulated Manure Solids Samples Collected From
Holding Ponds……………………………………… ....................………………………...…30
Figure 12. Comparison of Nutrient Concentrations From Various Clean-Out Planning Data
Sources ..................................................................................................................................... 38
Figure 13. Houle "AgiSprayer" Equipment Used For Agitation During Pond Clean-Out
Process .................................................................................................................................. 39
Figure 14. Comparison of Composite Sample Results to Samples Collected From Land
Application Equipment ............................................................................................................. 40
Figure 15. Nutrient Concentration Change in Samples collected From Tank Spreader During
Clean-Out at Case-Study Facility ............................................................................................. 41
Figure 16. Nutrient Concentration Change in Samples Collected From Tank Spreader During
Clean-out at a Second Participating Facility……………………………………………… .....37
Figure 17. Addition of Aluminum Chloride to Holding Pond……….………………………….43
List of Tables Table 1. Numbers of Swine Facilities by Conservation District (1999) ....................................... 18
Table 2. Plan Development and Clean-outs by County ............................................................... 27
Table 3. LAWMS Characteristics of Project Facilities ............................................................... 29
Table 4. Available Acreage and Land Application Acreage Requirements for Participating
Project Facilities ....................................................................................................................... 30
Table 5. Summary of Land Application Planning and Clean-Out Status .................................... 31
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The Land Application Project team:
Sandi Formica, Project Manager
Matthew Van Eps, Project Engineer
Tony Morris, Resource Specialist
Jason Beck, Ecologist
William McRee Anderson, Ecologist
The project team appreciates the courtesy and cooperation of all individuals and entities that
helped the team with the execution of the project, including:
ADEQ Administrative Staff
Arkansas Soil and Water Conservation Commission
U.S. EPA Region VI
Arkansas Pork Producer Association
Cossatot Conservation District
Conway County Conservation District
Newton County Conservation District
Pope County Conservation District
University of Arkansas Department of Agronomy
Tyson Foods Pork Group
Cargill Pork
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I. Introduction
Arkansas has ranked 16th
in the United States in pork production over the past 10 years, yielding
570,000 hogs annually. Virtually all of the commercial production is from the approximately
400 confined swine facilities in the state that utilize permitted liquid waste systems to manage
the manure generated during the raising of swine. Storm water run-off from confined animal
production activities has the potential to contribute significantly to non-point source nutrient
loading to lakes and streams in the absence of adequate manure management practices. The U.S.
Environmental Protection Agency (EPA) reports agricultural activity as the leading source of
pollutants that threaten the water quality of rivers, streams, and lakes in the United States. Over
time, non-point sources of nutrients, sediment, pesticides, and biochemical oxygen demand can
render a body of water unable to support aquatic life, threatening entire ecosystems1. Non-point
source pollution, including nitrogen and phosphorus, from confined animal operations poses a
threat to water resources in the north-western half of Arkansas. Land application of the manure
generated from confined animal facilities has resulted in atypically high nitrate levels being
measured in surface and ground water2. Nutrients from confined animal facilities are also the
subject of litigation for watersheds in Oklahoma that drain from Northwest Arkansas. Efforts to
reduce the impacts of Arkansas’ confined animal industry on water resources, while keeping
production viable and sustainable for the industry, have been welcomed by government, industry
and swine producers. A Recent announcement indicating that many contracts will be terminated
at swine facilities in Arkansas does not diminish the importance of proper manure management,
and the work presented in this report will be applicable in addressing system closures in an
environmentally sensitive manner.
This report is a summary of a cooperative 3 year effort to protect water quality by improving
manure management at confined animal facilities having liquid animal waste management
systems (LAWMS). The project objectives were to:
$ Ensure the proper land application of manure from poorly maintained liquid waste
systems;
$ Assist cooperating farmers in recovering full liquid waste system storage
capacity;
$ Encourage better utilization of liquid waste derived nutrients, including a
reduction in the over application of phosphorous;
$ Encourage swine producers to recognize both the potential environmental hazards
and nutrient benefits of their liquid manure; and
$ Demonstrate manure utilization technologies that reduce the over application of
phosphorous from animal manure.
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The project goal, to protect and improve water quality in the state, was achieved through the
above objectives and by working directly with producers requesting assistance and Conservation
District Water Quality Technicians to develop farm specific clean-out plans based upon the
following factors:
1. Permitted land application acreage
2. Land application acreage cover crop
3. Mass of nitrogen (N) and phosphorous (P) in ponds based upon physical measurements
4. Soil test phosphorous levels in application site soils
5. Waste management equipment available to the farmer
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II. Background
Most confined swine facilities in Arkansas are small family owned farms that raise swine under
contract to large agribusinesses. The majority of these facilities were built during a period of
rapid industry growth in the 1980's. Liquid animal waste management systems (LAWMS) are
configured to store swine manure and waste water (rain and drinking water waste) in earthen
storage structures, utilizing recirculated water from storage to flush manure from the swine
barns. The storage structures are typically configured in a two-cell design consisting of a settling
basin, used to remove solids from suspension, and a holding pond, used for solids and waste
water storage. Recirculated water from the holding pond is released from 300 to 500 gallon
concrete flush tanks one or more times a day, to flush manure from the shallow concrete gutters,
which extend the length of the barns at a 2% grade. Settling basins are generally designed for 45
days of solids storage, and holding ponds are typically designed for a minimum of 120 days
storage of manure and waste water. The manure storage ponds are designed to be completely
emptied and the contents land applied at least twice per year.
Field observations and empirical data from the Buffalo River Swine Waste Demonstration
Project (Swine Project) revealed a number of common problems associated with improperly
maintained waste systems at swine production facilities in north-central Arkansas 3. Through
work conducted in the Swine Project it was noted that manure storage ponds at farms within the
Buffalo River Watershed were only occasionally, if ever, completely cleaned out prior to 1996.
Most farmers were observed to manage liquid levels in their storage structures by pumping from
the tops of the ponds with incomplete or no mechanical mixing of the contents. In addition, most
of the material removed from the ponds was generally applied to pastures that were the most
accessible relative to the barn complex. Farmers routinely maintained the minimum freeboard
levels in order to be in compliance with specific permit conditions and regulations; however,
ponds were not emptied for maximum nutrient utilization or storage capacity prior to the winter
months. Many farmers stated that if they completely emptied their ponds, they would then have
to use fresh water for flushing the barns until water levels in their ponds recovered to the point
where the flush pumps could be used. The problems associated with the operation and
maintenance of the LAWMS observed during the Swine Project resulted in the potential for
tremendous quantities of nutrients being transported to surface waters.
The Swine Project demonstrated that LAWMS that were not maintained resulted in solids
accumulating in the holding pond. With time, accumulated solids become increasingly difficult
to remove from LAWMS due to settling, biochemical breakdown and compaction. As solids
accumulate in manure storage ponds, there is less pond volume available for the required 120
days of storage, resulting in greater potential for pond discharges. The need to land apply at
inappropriate times, such as, the dormant season for the cover crop, to saturated or frozen soils,
or prior to or during storm events is also increased. Accumulation of manure solids in LAWMS
resulted in many producers having to spend more time than was anticipated on the operation of
their LAWMS in order to stay within some of the requirements of their permits.
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During the Swine Project, the
pond contents of LAWMS at
five participating farms were
extensively characterized to
determine nutrient and solids
concentrations. The results of
this work demonstrated that
pond contents are not uniform
mixtures, but are stratified. A
surficial gray water layer, with
relatively low concentrations of
solids and nutrients was found
on top of a solids layer having a
comparatively high
concentration of solids and
nutrients. The stratified pond
contents required considerable
mechanical effort during
agitation in order to arrive at a
homogeneous mixture that could
be pumped and evenly distributed onto application sites. Figure 1 compares typical nutrient
concentrations observed in samples collected at discreet intervals within maintained and non-
maintained swine farm holding ponds. If LAWMS holding ponds are routinely cleaned-out
(maintained) a more agronomically favorable nitrogen to phosphorus (N to P) ratio can exist in
the ponds. However, if a farmer merely land applies gray water in order to maintain the required
minimum freeboard levels (non-maintained), N is lost through ammonia volatilization and
microbiological activity while P accumulates, resulting in a more unfavorable N to P ratio. As an
example, the ratio of nitrogen and phosphorus uptake by bermuda and fescue grass is
approximately 10 to 1 (NRCS Agricultural Waste Management Field Handbook)4. In other
words, for every 10 pounds of nitrogen that a pasture of fescue assimilates, one pound of
phosphorus will be utilized. When fertilizer is applied to a crop it should be done in a manner in
which the requirements of the crop are met without over-applying nutrients. Manure storage
ponds that are not routinely maintained result in an unbalanced N to P ratio. Years of continued
solids accumulation will lead to a high concentration of nutrients, agronomically unbalanced N
to P ratios and an overall loss of storage volume in LAWMS.
A component of the Swine Project was developed to identify the effect that soil type has on
nutrient losses from fields receiving liquid manure applications. In that work, swine manure
slurry was land applied to test plots with identical slopes and vegetation and at the recommended
N based loading rate for a Tall Fescue cover crop. The test plots were then rained on at a
specified intensity and a known volume using rainfall simulation equipment. It was found that
the application of waste significantly increased nutrient concentrations in storm water runoff as
well as runoff volume. Depending upon soil type, 1.8 to 6.2% of total N, and 2.0 to 9.6% of total
P that was land applied was lost in storm water runoff from manure fertilized test plots5. This
work indicated that, even under controlled conditions, nutrient loss occurs through storm water
runoff following the land application of manure. In order to land apply liquid manure in a way
Figure 1. Typical Concentrations of Nutrients in Maintained and
Non-Maintained LAWMS
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that will result in the least amount of nutrients being transported to lakes and streams as non-
point source pollution every effort must be made to control the pertinent variables. Land
application variables can be best controlled by accurately estimating the nutrient load contained
within storage structures and then proceeding through a thoughtful, careful planning process in
which an easily followed course of action is outlined and implemented.
Another nutrient management related concern identified in the Swine Project was the build up of
phosphorus in the soil, generally described by soil test phosphorous (STP), on certain application
sites. STP concentrations in the soils of the most convenient fields for land application, typically,
those fields immediately adjacent to the LAWMS, commonly exceeded 300 pounds per acre.
This value exceeds the concentration considered by many professionals in the field of non-point
source pollution to be an upper cut off level for additional applications of the nutrient. Values
approaching or exceeding the upper limit of the Melich III test method are not uncommon in
areas with high densities of confined animal production facilities. The high STP issue created
additional difficulties when attempting to address solids and nutrient accumulation problems in
LAWMS. Pastures exceeding the 300 pounds per acre concentration could not be recommended
for land application of accumulated swine manure solids during the Swine Project.
Many of the problems observed during the Swine Project regarding the operation of LAWMS
could be attributed to, or exacerbated by, the geographic locations of the facilities. All of the
participating farms were constructed within hilly or mountainous terrain which greatly affected
all aspects of manure management activities. From controlling and excluding storm water, to
accessing holding ponds and land application sites located on steep hill sides with equipment,
farm locations created operational challenges for farmers. However, the terrain on which the
cooperating Swine Project farms were located was not unique to the Buffalo River watershed,
hillsides and hilltops are frequently the locations for confined animal facilities in Arkansas.
Questions were raised as to whether the accumulation of manure solids and associated nutrients
observed in the Swine Project was merely a localized phenomenon or were the issues noted with
LAWMS common throughout the swine industry in Arkansas.
In Arkansas, the swine production industry is concentrated in the north-western part of the state
(Figure 2). Farms are typically concentrated in a region to reduce integrator expense associated
with the transportation of animals and feed as well as to facilitate better oversight of the
production process. Few swine facilities are located in the Arkansas delta region where manure
derived nutrients could be readily utilized by grain or cotton crops. The scarcity of confined
animal facilities in Eastern and Southern Arkansas may be due to the land and time requirements
associated with the current agricultural economy of the “delta” region. In any event, most
confined animal operations are located in a portion of the state that is often hilly or mountainous
with soils that are not highly productive and cannot utilize a large mass of nutrients. The general
geographic location of the industry highlights the necessity for effective manure management.
As seen in Figure 2, most swine production is concentrated within a 40 mile radius of Dierks in
Howard County, Russellville in Pope County and Fayetteville in Washington County. From a
nutrient management perspective, it should be noted that the areas of high swine farm density
overlap areas of high poultry broiler farm density.
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Figure 2. Locations of Swine Facilities in Arkansas
Based upon solids accumulation related environmental concerns, the Environmental Preservation
Division of the ADEQ and the Arkansas Pork Producers Association cooperatively initiated the
State-Wide Pond Solids Survey 6. The goal of the Solids Study was to assess the extent of the
solids and nutrient accumulation problem within swine LAWMS throughout Arkansas. Over a
two month period in the fall of 1997, 10% of the approximately 400 swine farms in the state with
permitted liquid waste systems were randomly selected for pond sampling. Staff from the
Environmental Preservation Division visited the selected farms and collected representative
samples of the storage pond contents utilizing tools and methods developed during the Swine
Project. Also collected during this study was basic information about the LAWMS and operator
experience in running the systems. A significant finding of the Solids Study was that a majority
of the facilities had more manure solids in the holding ponds than should have been there based
on the waste system design. Generally, LAWMS in Arkansas are designed to have
approximately 20 percent of the pond volume occupied by accumulated solids prior to a clean-
out. The normal accumulations of solids are intended to be removed each year. Of the 40 waste
systems sampled, 35 systems had more than 20 percent of the design pond volume occupied with
accumulated manure solids. Furthermore, 24 of the facilities had more than 40 percent of the
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pond volume filled with manure solids. None of the producers had ever completely emptied the
contents of their LAWMS and only half of the facilities utilized some type of mechanical mixing
or agitation when pumping liquid manure from their systems.
Analysis of manure samples
collected from the storage
structures in the Solids Study
confirmed previous results from
the Swine Project. Ponds that
were not maintained, i.e. solids are
not removed annually, have much
higher nutrient concentrations.
Figure 3 illustrates the difference
of nutrient concentrations in
maintained and non-maintained
LAWMS. Non-maintained
systems with accumulated solids,
had concentrations of total N and
P that were greater than
maintained systems by 3.2 and 3.8
times respectively. Based upon the
observations of the Solids Study,
in order to clean-out a LAWMS that had not been maintained, the amount of land required to
assimilate the accumulated solids and associated nutrients would be 3 to 4 times that which
would be required if the systems were maintained.
An interesting finding from the Solids Study work involved the efficacy of agitation equipment
utilized for mechanical mixing of manure storage pond contents during land application.
Surprisingly, when the accumulated solids content of ponds from farms utilizing agitation
equipment was compared to farms without equipment, there was essentially no difference. This
indicated that farmers were unable to thoroughly mix the contents of their holding ponds and
remove manure solids at many facilities. This is likely due to equipment being inappropriately
sized or typed, insufficient access to all portions of the ponds, and/or underpowered or incorrect
use of equipment. The inefficiency of agitation equipment is not only another potential cause for
manure solids accumulation in swine LAWMS, it can also be a waste of time, money and effort
by the individual farmer.
The results of the Swine Project and the Solids Study indicated that the difficulty of managing
manure solids in LAWMS was a statewide occurrence in Arkansas. Accumulating solids in
manure storage ponds was causing producers to spend inordinate amounts of time with their
systems and generally, increased the potential for ponds to overflow and the need to land apply
liquid manure during times of the year that would result in large amounts nutrients reaching
surface waters. Results from these studies were presented to facility operators across the state to
inform them of the problems associated with accumulated manure solids. However, it was not in
the interest of protecting water quality to remove accumulated manure solids without a plan
specifically addressing the high concentration of nutrients. A planning system that could help
Figure 3. Nutrient Concentration Differences in Maintained and
Non-Maintained LAWMS
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swine facility operators address solids accumulation problems in an environmentally responsible
manner was needed.
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III. Land Application Project Description and Implementation
The results of the Swine Project and the Solids Survey indicated that accumulated manure solids
in LAWMS at swine facilities was a common occurrence throughout the swine industry in
Arkansas. Also apparent was that accumulated manure solids contained much higher nutrient
concentrations than would be indicated in the facility waste management plan. Although this
information was brought to the attention of both producers and the industry, the EPD did not
want to create a situation that would lead to multiple facilities within a single drainage basin
removing accumulated solids from their LAWMS without appropriate planning. There was the
potential for tremendous amounts of nutrients being washed into surface waters if indiscriminate
removal and land application of storage pond contents was to occur. A more environmentally
acceptable means of addressing the problem would be to provide planning assistance that would
reduce the amount of nutrients entering lakes and streams by providing guidance to individual
farmers that would improve nutrient utilization and overall manure management economics. In
order to provide effective assistance, the proposed project was structured to involve the producer,
local conservation districts and the EPD of ADEQ to develop plans that were economically
feasible, environmentally responsible, and within the limits of the state water permit issued for
the facility.
In an effort to address LAWMS issues observed in the Swine Project and the Solids Survey, the
“Land Application of Accumulated Solids From Liquid Waste Systems Demonstration Project”
(Land Application Project) was initiated. The project goal was to work with the swine industry
to address solids and nutrient accumulation problems at confined animal facilities having
LAWMS. The essence of the project involved working with farms that had on their own,
determined that there was a problem with accumulated solids within their LAWMS. Through
their own volition, participating farmers received assistance and training in proper waste system
operation as well as optimum management of nutrients derived from the system. Emphasis was
placed on accurately identifying waste characteristics and achieving the maximum fertilizer
benefit and the greatest protection of water quality. The EPD assisted farmers in 1) sampling
storage ponds, 2) proper land application of waste including information on nutrient benefits and
water quality protection, and 3) maintaining accurate and complete records of waste application
activities.
Participants in the project included:
Swine Corporations (Integrators)
Individual Swine Producers
Arkansas Pork Producers Association
University of Arkansas Department of Agronomy
Conservation Districts
Arkansas Soil & Water Conservation Commission
Results from the Swine Project and Solids Study were presented to farmers, to integrators and to
Conservation District Boards. ADEQ Regulation No. 5 requires all farmers having LAWMS to
attend an annual training meeting. These meetings provided a venue for direct interaction with
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every swine producer in the state. Prior to the official start of the Land Application Project,
information was presented at the meetings which emphasized the importance of removing solids
annually from LAWMS in order to reduce the amount of time spent managing manure and to
reduce the impact of swine facilities on water quality. Following the start of the project,
presentations at Regulation No. 5 meetings continued to focus on the problems associated with
accumulated manure solids and the Land Application Project was introduced. At the meetings
the following year, a case study was presented so that the farmers could actually see how the
clean-out plan development process took place. Copies of slides presented by project staff at
Regulation No. 5 meetings have been included as Appendix A of this report. Farmer
participation in the project was entirely voluntary and no costs were incurred by the farmer for
receiving planning assistance. Costs associated with sample collection and analysis, file review,
and plan development were covered entirely by the project budget.
The project team felt that, in order to improve farmer
participation, any planning assistance provided to
farmers in order to clean-out accumulated manure
solids should be coordinated through the local
Conservation District offices. Local Conservation
District offices had an established working
relationship with many farmers and provided an
avenue of trust and confidence that improved farmer
interest and participation in the program. All
Conservation Districts where swine facilities were
located were invited to participate in the project. It
was decided that personally meeting with the ten
districts having the greatest number of swine
facilities would be the best way to encourage their
voluntary participation. The districts having the
greatest number of swine facilities are shown on the
map in Figure 1 and are listed in Table 1, along with
the number of permitted farms within the district. A
formal presentation on the solids and nutrient
accumulation issue was made to each of the
Conservation District boards in order to solicit their
direct participation. Copies of the slides presented at
the board meetings are included in Appendix A.
Other conservation districts having swine facilities in their areas were sent a letter describing the
project and offering assistance to them should any producer from their district request a LAWMS
clean-out plan. Meeting with the conservation district boards required a significant investment
of time, but ultimately helped in generating interest from farmers and kept the planning process
local.
The project team also met with representatives of the major integrators and presented
background information developed from the Swine Project and Solids Survey. The goals of the
Land Application project were discussed and their cooperation in the project was solicited
allowing project staff access to contracted farms in order to evaluate the LAWMS of
Table 1. Numbers of Swine Facilities by
Conservation District (1999)
Rank Conservation
District
Number
of Farms
1 Mill Ck. (Howard) 50
2 Pope 43
3 Cossatot (Sevier) 42
4 Yell 28
5 Pike 27
6 Conway 23
7 Polk 21
8 Washington 21
9 Montgomery 20
10 Benton 18
11 Perry 12
12 Little River 12
13 Logan 12
14 Hempstead 12
15 Newton 11
16 Clark 9
17 Madison 8
18 Johnson 6
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participating facilities.
Pond Clean-Out and Land Application Planning
The system for developing pond clean-out plans was designed to proceed through the
conservation districts. The hope was that after completion of the project, water quality
technicians from the conservation districts would be able to provide the types of assistance that
EPD provided during the project. If an individual farmer suspected a solids accumulation
problem in his LAWMS, he would notify his local Water Quality Technician and request
assistance. Most producers were aware of a solids accumulation problem in their LAWMS,
because when they pumped water from their ponds, they could see “islands” of solids appear.
Some producers also experienced an inability to utilize their recycle flush pump due to
accumulated solids.
After a request for planning assistance was made, the Water Quality Technician then contacted
EPD staff who would schedule a trip to the farm to gather some of the necessary information
needed to develop a clean-out plan. In order to reduce the environmental effects and economic
burden of removing accumulated solids from LAWMS, the EPD staff developed farm specific
clean-out plans based on:
1. The mass of N contained within the ponds;
2. The mass of P contained within the ponds;
3. Permitted land application acreage available to the farmer;
4. The specific cover crop nutrient uptake requirement for maximum agronomic benefit;
5. Concentrations of STP on permitted land application sites;
6. Waste management equipment and resources available to the farmer;
The completed plan was discussed with the water quality technician and then delivered to the
farmer who was responsible for implementing the plan. The following section provides details
of the process for developing the LAWMS solids clean-out plans.
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IV. Solids Clean-Out Plan Development Strategy
Liquid Manure Characterization
The first step in preparing a plan to remove accumulated solids from a LAWMS was to estimate
the quantity and character of the manure being stored in the LAWMS. In order to accurately
characterize the manure in LAWMS, a sampling protocol was developed that would result in the
collection of samples that would be representative of the manure in the systems. The sampling
procedures developed were based on previous LAWMS sampling experience as part of the
Swine Project. Samples of the liquid manure in the LAWMS were collected using a modified
Coliwasa sampling device. This device is constructed of clear plastic graduated in 1 inch
increments and utilizes a rubber plunger and rod to open and close the sampler. It was found that
the composition of typical swine waste solids inhibited adequate sealing of the rubberized
plunger. The plunger was modified by increasing the bevel angle in order to overcome this
limitation. The modular design of the device allowed for adding the appropriate length of tubing
depending on pond depth. The sampling device could obtain column samples from holding
ponds up to a depth of 12 feet.
Figure 4. Collection of LAWMS Pond Samples
Composite samples of the holding ponds and settling basins (when present) were collected from
a boat, which was maneuvered by installing a guide rope across the pond along the sampling
paths (Figure 4). The column samples were taken at four equidistant locations along two passes
across the width of the holding pond. The discreet column samples were mixed thoroughly in a
bucket, and then a composite sample of the mixture was removed and placed in a sample bottle
for analyses (Figure 5). The method for collecting a composite sample from a settling basin was
the same as the holding pond, with the exception that four discreet samples were collected during
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a single pass across the length of the pond for compositing into one sample. At each of the
column sample locations, the total height of the collected column sample, the thickness of
stratified solids and liquid layers, and the total depth of liquid manure in the ponds were recorded
on a data collection sheet (Appendix B). The samples were delivered to the ADEQ laboratory in
Little Rock where they were then analyzed for TKN, NH3-N, NO3-N, TP, Ortho-P, TDS, TSS,
Cl, SO4, and TOC using EPA-approved methods.
Figure 5. LAWMS Pond Sample Collection Methodology
Some difficulties were encountered while using the sampling device. For example, accumulated
solids would not always freely move into the sampling device. These solids tended to block the
opening and prevent collection of representative samples of the entire depth of the pond. To
improve the quality of sample collected, the device was moved in an up and down manner to
facilitate more material entering the sampling device. The difference between the height of
sample collected and the total depth of the pond, was assumed to be made of Aunsampled@ solid
material. The mass of nutrients associated with the Aunsampled@ solids material was estimated
and then added to the mass of nutrients determined from the sampling event. In addition to
composite samples, discreet samples of the solids materials and the overlying grey water were
collected and analyzed from many of the facilities.
The volume of liquid manure was estimated based on measurements collected while in the field.
The holding pond/settling basin dimensions at the waterline and at the top of the pond levee and
the amount of available freeboard were determined by direct measurement. Using this
information, along with the depth of liquid manure in the pond, a determination of the volume of
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manure that was contained in the ponds could be made. Estimations of volume of manure in the
ponds could have been made by utilizing the dimensions of the pond in the construction plans for
the facility. However, as was frequently noted during the Solids Study, ponds were rarely built
as shown in construction drawings. Site limitations were often the cause of this discrepancy.
Visiting each of the farms and collecting the necessary data was crucial in order to develop site-
specific clean out plans. Included in Appendix B is a copy of the sample collection data sheet
and standardized pond sampling procedures used in this project.
Waste Management Plan Review
The second step in developing a LAWMS solids clean-out plan was to obtain and review the
farm specific Waste Management Plan (WMP), the ADEQ State Water Permit, and the most
recent Regulation No. 5 Annual Report submitted to ADEQ by the facility operator. From the
WMP, the amount of acreage available for land application, as well as the cover crop on the
pastures receiving liquid manure, could be ascertained. The ADEQ permit issued for the facility
was reviewed to determine the permitted acreage available for manure applications and the
maximum N based application rate. Soil test phosphorous (STP) concentrations for each field
that would potentially receive liquid manure were obtained from the Regulation No. 5 annual
report that each facility with a permitted LAWMS is required to submit to ADEQ.
Plan Development
With the information listed above, an initial solids clean-out plan was developed. The initial
plan provided the basic elements needed by the operator to accomplish the clean-out. A meeting
was then arranged with the farmer, the conservation district, and EPD project staff, so that the
information used to formulate the initial clean-out plan could be reviewed and finalized.
Attached as Appendix C is the LAWMS Solids Clean-Out Plan checklist and form developed
and used in the project. At the meeting, farm specific issues were discussed with the farmer so
that the final plan would be tailored to the needs and limitations of the particular facility. Issues
that had to be addressed in the finalized plan were numerous and varied with each facility.
However, issues common to all farms included: application rates; land requirements; equipment
requirements to accomplish the clean-out task; and the economics involved with removing large
volumes of accumulated manure solids. The farmer left the meeting with a clean-out plan
summary that included: the volume of manure; concentration of nutrients; total pounds of
nutrients contained in the LAWMS; the permitted acreage; STP values for each field; and
acreage requirements for the clean-out. Also, a copy of the composite manure sample analysis
was given to the farmer. Each farmer was made aware of the known waste management
companies servicing the swine industry in the state and was provided with a list of such vendors
(Appendix D).
The manure and nutrient application rate was one issue discussed with every farmer. As
indicated by the Swine Project and Solids Study, the concentration of nutrients in accumulated
manure solids is very high compared to concentrations indicated by the WMP. Typically, in
LAWMS with accumulated manure solids, the relative concentrations of N to P is approximately
a one-to-one ratio, compared to a ratio of 3 to 1 for manure as excreted by gestating sows 7.
Current planning practices in Arkansas develop WMPs using N as the basis for land application
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24
rates since N is the limiting nutrient to forage growth. If the accumulated manure were to be
land applied at the N based application rate, the amount of P applied would greatly exceed the
cover crop=s ability to uptake P. This is cause for concern since phosphorus is a potential
pollutant in surface water. Reducing phosphorus loss from manure fertilized fields through
storm water runoff had to be addressed when developing the clean-out plans. As a matter of
project policy, EPD project staff recommended that farmers apply their manure at 2 the N based
application rate in order to reduce the over-application of phosphorus. Application of manure at
half the N rate not only reduced the amount of P that would potentially run-off during rainfall
events, but it also reduced the rate at which pastures receiving manure accumulate STP. If at
some future date WMPs for confined animal operations were to be based upon STP and an
application index, many fields might be unusable for manure application as a result of current
poorly planned nutrient applications. Farmers were also encouraged to land apply the manure
during the months of greatest nutrient demand by the growing cover crops.
Another method of reducing P loss was to land apply manure to fields with lower STP values.
While working on the Swine Project, high STP values were frequently noted on the fields nearest
to the barn complex and waste system. Similar conditions were observed during the Land
Application Project (Figure 6).
Therefore, as a matter of practice,
discussions with each farmer about
nutrient management included
ways of controlling and reducing
STP levels. Farmers were
encouraged to avoid applications of
accumulated manure solids with
high P concentrations to fields with
greater than 300 pounds per acre
STP. In addition, it was
recommended that fields adjacent
to the LAWMS could be held in
reserve in order to keep them
available for emergency pond level
control throughout the remainder of
the year. Management practices that could be used to control or reduce STP in storm water
runoff were presented to all
participating farmers. Mining of P
from fields having high STP levels
by intensively managing fields for
hay production and the use of pasture renovation in conjunction with manure applications was
encouraged. Effective mining of P requires that forage be removed from the field, as opposed to
allowing cattle to graze on the grass and, in effect, recycling the nutrients back to the pasture.
Utilization of pasture renovation, in theory, can increase the distribution of P through a greater
soil depth as well as reduce the amount of storm water runoff by increasing the porosity of
pasture soils. The effectiveness of pasture renovation in Arkansas is being investigated by the
EPD in the “Pasture Renovation To Reduce Nitrogen and Phosphorous Run Off From Fields
Fertilized With Animal Manure Demonstration Project” currently underway8. In addition to the
Figure 6. High STP Adjacent to Facility
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25
practices described above, the importance of monitoring STP levels on each field through regular
testing and utilizing good sampling methodology was stressed.
Since, historically, WMP designs set the manure application rates based upon the N content of
the manure expected from the number of animals in confinement, many farms acquired the
minimum amount of permitted land required to assimilate the predicted annual nutrient load.
Therefore, when LAWMS accumulate manure solids and associated nutrients, there is frequently
a shortage of land application acreage to accommodate a system clean out, particularly, if the
manure is applied at one-half the nitrogen rate. During the Land Application Project planning
process, solutions to this commonly observed problem included adding land application acreage
to the permit or reducing the rate of application and accomplishing the clean out over two or
three growing seasons. If producers elected to add additional land to their permits, they were
advised to add as much as possible, since the associated cost of modifying a permit is not
dependent on the acreage being added. Producers were encouraged to actively develop a market
for the fertilizer by adding as much of their neighbors land to the permit as possible within a
reasonable haul distance from the facility. Surplus manure could then be sold, partially
offsetting management costs.
Knowing the manure volume, associated nutrient content and the acreage required for the clean
out, the farmer was better able to determine his financial ability to address the problem. Few of
the farmers who requested planning assistance through this project had the necessary equipment
to manage high solids content sludge or the time required to accomplish the clean-out task on
their own. Clean-out cost estimates for participating farms, based upon commercial waste
management services pricing of approximately 1 cent per gallon, ranged from $3000.00 to over
$30,000.00. Few Arkansas swine farmers have the financial means for a one-time clean out of
years of accumulated solids. This financial impediment, in addition to insufficient permitted
land application acreage, resulted in many producers electing to have their plans developed so
that the problem could be addressed incrementally over two or more growing seasons.
After the plan was finalized, a clean-out plan summary was completed. The summary was
intended to be a document that could be given to a manure management contractor or used by the
farmer to follow during clean-out activities. It included the pond volume and nutrient content
estimates as well as nutrient application rates for each field. Implementation of the final plan
within the target time frame was up to the farmer. Follow up visits by water quality technicians
or project staff were made to many cooperating farms in order to monitor progress. A copy of
the Clean-Out Plan form is included in Appendix E of this report.
After completion of the project, a 3 ring binder containing all of the necessary information to
develop a comprehensive LAWMS solids clean-out plan was presented to participating
Conservation Districts, ASWCC, Arkansas Cooperative Extension Service, the Arkansas Pork
Producers, and other entities. This binder and contents are referred to as the “Swine Manure
Solids Clean-out Planning Resource Notebook.” The notebook included most of the information
contained in the appendix of this report, as well as tools to make the planning process quicker.
Specifically, a spreadsheet program was provided that allows planners to quickly calculate
manure volume and nutrient masses found in a LAWMS given that the system has been sampled
previously. A copy of the notebook can be obtained electronically from the ADEQ,
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26
Environmental Preservation Division.
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27
V. Project Results
Eighteen facility operators
requested LAWMS clean-out
planning assistance through the
Land Application Project. The
location of the facilities that
participated in the program are
shown in Figure 7. Although the
project staff met with, presented
and discussed the issues of
accumulated swine manure solids
with 10 conservation districts,
only 4 of those districts had farms
that participated in the project.
Two districts that had
participating facilities did not
receive a formal visit. Table 2
shows the 6 participating
conservation districts and the
number of clean-out plans
developed and executed. The top
swine producing district in the
state (Howard County, Table 1)
did not have any farms participate in the program. Participation rates were dependent on
producers’ interest in obtaining assistance and whether or not the conservation district was
actively promoting the assistance being provided through the project. In Sevier County, Cossatot
Conservation District, participation rates were the highest due to the interest and promotion of
the project provided by the water quality technician.
Table 2. Plan Development and Clean-outs by County
County Plans
Developed
Clean-Outs
Completed Conway 2 2
Monroe 1 0
Newton 2 2
Pope 2 2
Searcy 1 1
Sevier 9** 0** **3 Facilities had lagoon systems that did not require a clean-
out
Table 3 provides an overview of the LAWMS characteristics, the concentration and mass of
nutrients and the amount of accumulated solids at facilities that received planning assistance.
Participating facilities were swine operations with the exception of one dairy facility. Although
the project was originally oriented towards the swine industry, the principle investigator and
project staff agreed that any facility having a LAWMS could receive clean-out planning
assistance through this project. Reviewing the characteristics of the facilities participating in the
project, the differences of the types of LAWMS can be identified. None of the facilities that
Figure 7. Locations of Participating Facilities
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28
participated in the project had LAWMS that were identical. Some facilities were similar in one
aspect, pond size for example, but varied in the available acreage or concentration of nutrients in
the system. The volume of liquid manure that needed to be addressed during the course of the
project ranged from approximately 175,000 gallons to near 3.2 million gallons. Concentrations
of nitrogen and phosphorus in the systems ranged from 6 and 7 lb/1000 gal to 65 lb/1000 gal
respectively. The amount of pond volume occupied by accumulated manure solids ranged from
4 to 100 percent. Differences in these and other variables identified while providing planning
assistance to farmers participating in the project emphasized the importance of farm specific
planning when developing plans for a LAWMS solids clean-out.
Every facility operator that requested clean-out planning assistance through the Land Application
Project received a completed plan. A copy of an example completed plan is included in
Appendix F. Of the 18 facilities that requested assistance for developing a clean-out plan, only 7
facilities were able to execute the plans by the end of the allotted project time-frame. However,
three of the 11 remaining facilities that had not executed a LAWMS clean-out were Lagoon
designs that were in a condition that did not require immediate removal of the solids. The factors
affecting the ability of a producer to execute a clean-out plan include: pond size; pond access;
insufficient permitted application acreage; high STP on some fields; travel distance from the
waste system to suitable permitted application sites; and cost associated with hiring a contractor.
All of these factors are interrelated, for example, the size of the pond increases the amount of
nutrients that would be land applied, which increases the acreage requirements. Also, the larger
the storage pond, the greater the cost for cleaning out the LAWMS will be. Greater amounts of
nutrients also increased the travel distance required to reach enough land to assimilate the
nutrients which in turn increases cost. These issues were common to all of the facilities
requiring a solids clean-out, and for the systems that were not able to complete the clean-out by
the end of the project, a combination of these factors was frequently to blame.
The issue of available acreage and distance to land was one that frequently resulted in delays in
executing a LAWMS clean-out. Table 4 indicates the acreage requirements for land applying the
accumulated manure and nutrients from the facilities participating in the project. In Table 4, the
number of acres indicated on the permit, the number of acres with STP over 300 lb/ac, acreage
available to receive land applied manure after excluding high STP acreage, the number of acres
needed to land apply at the full nitrogen application rate, and the acreage required to land apply
at one-half the nitrogen application rate are listed for each facility.
Review of the data in Table 4 indicates that 7 of the 18 facilities did not have sufficient acreage
to have the manure and nutrients applied at the full nitrogen application rate. As the purpose of
the planning process was to reduce the over application of phosphorus, plans were developed
such that the manure would be applied at one-half the nitrogen application rate. Application of
accumulated manure solids at the permitted nitrogen application rate would have resulted in poor
utilization of nitrogen fertilizer value and over application of phosphorus. Additionally, while
the State issued permit may allow up to 300 lb N/ac/yr in some permits, the intent of the
permitted application rate is to have multiple applications of manure throughout the growing
season that when totaled are equivalent to 300 lb N/ac/yr. All of the facilities participating in the
project agreed that the best use of the accumulated manure was to land apply at one-half the N
rate. Based on the one-half
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29
Table 3. LAWMS Characteristics of Project Facilities
Farm
Number County
Type of
Operation
Number of
Animals LAWMS
Manure
Volume (gal)
N and P Conc
(lb/1000 gal) Mass N and P (lbs)
% Pond
Volume
69 Sevier Finishing 2400 HP
SB
568,400
210,700
50
38
38
18
28,500
7,960
21,500
3,800 40
38 Sevier Farrowing 300 sow HP 480,000 24 30 12,000 14,000 45
72 Sevier Finishing 2500 Lagoon 1,401,000 55 65 77,150 90,900 55
34 Sevier Farrowing 300 sow HP
SB
920,000
57,000
38
28
30
20
35,000
1,600
27,600
1,100 42
88 Sevier Farrowing 300 sow Lagoon 1,454,000 13 15 19,000 22,000 5
95 Sevier Farrowing 300 sow Lagoon 1,712,000 6 7 10,600 12,700 7
98 Sevier Farrowing 300 sow Lagoon 1,283,000 6 10 7,400 13,200 4
25 Sevier Finishing 2500 Lagoon 3,158,000 34 26 107,000 82,000 40
61 Sevier Farrowing 300 sow HP 577,000 29 34 16,700 19,700 58
15 Conway Finishing 4000 HP
SB
1,000,000
215,000
50
32
45
18
50,000
6,900
45,000
3,900 40
86 Conway Finishing 4080 HP
SB
1,844,000
376,254
45
23
46
28
83,000
8,700
84,000
10,600 36
51 Monroe Finishing 400 HP 1,381,000 47 36 65,000 50,000 100
30 Pope Farrowing 300 sow HP
SB
280,000
35,000
65
29
65
22
18,000
1,000
18,000
800 50
163 Pope Finishing 2400 Lagoon
SB
549,000
n/a
40
n/a
33
n/a
22,000
n/a
18,000
n/a
29
n/a
16 Newton Farrowing 300 sow HP
SB
150,000
22,000
28
37
26
31
4,300
810
4,000
680
38
n/a
19 Newton Farrowing 300 sow HP
SB
153,000
170,000
22
25
23
24
3,400
4,300
3,500
4,100
22
9
25 Searcy Farrowing 340 sow HP
SB
220,000
40,000
48
28
50
25
10,500
1,100
10,900
1,000
40
100
37 Searcy Dairy 100 cow HP 220,000 14 5 3,100 1,100 47
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30
application N rate, all but two facilities that had a clean-out plan developed needed additional
acreage in order to complete the clean-out process in one year. The time requirements and
difficulties in obtaining additional land precluded many operators from conducting a clean-out of
their LAWMS immediately upon receipt of the clean-out plans. This was the case for a number
of the facilities in Sevier County where land, that is available to be added to a permit, is scarce
due to the number of confined animal operations in the area (both swine and poultry).
Table 4. Available Acreage and Land Application Acreage Requirements for Participating Project Facilities
Farm
Number County
Permitted
Acres
Acres with
>300 lb/ac
STP
Available
Acres
Acres Required
for Full Nitrogen
Application Rate
Acres Required
for 2 N
Application Rate
69 Sevier 545* 5 460 151 302
38 Sevier 8 40 58 50 100
72 Sevier 187 67 120 240 480
34 Sevier 261 0 261 152 304
88 Sevier 86 2 84 65 130
95 Sevier 37 0 37 36 72
98 Sevier 69 0 69 190 380
25 Sevier 214 80 134 353 706
61 Sevier 57 37 20 54 108
15 Conway 708** 0 476 381 762
86 Conway 316 0 316 553 1106
51 Monroe 480 0 480 648 1296
30 Pope 120 42 78 65 130
163 Pope 113 0 113 72 144
16 Newton 111 18 93 23 46
19 Newton 69 17 52 43 86
25 Searcy 278 9 269 70 140
37 Searcy 45 29 16 21 42
* All permitted land application acreage is owned by other landowners. Manure application activities are subject to
individual owner land management requirements.
* *Approximately 232 acres are located more than 10 miles from the barn complex.
A summary of the clean-out activity status for each of the 18 facilities participating in the project
can be found in Table 5.
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Table 5. Summary of Land Application Planning and Clean-Out Status
Farm
Number County Clean-Out Status Summary of Clean-Out Activity
69 Sevier Partial Clean-Out
Solids were removed from the settling basin and approximately half of the accumulated
solids were removed from the holding pond. Both of the ponds are difficult to access
with waste management equipment due to steep inside and outside levy slopes. None of
the permitted application acreage is owned by the farmer, therefore all land application
activities are subject to the management decisions of the individual land owner.
38 Sevier Partial Clean-Out Approximately half of the accumulated solids were removed from the holding pond.
72 Sevier Partial Clean-Out
The farmer added 100 acres of land application acreage to the permit. The facility has a
large holding pond with narrow levee crest and steep inside and outside slopes which
severely limits equipment access. The land application sites in closest proximity to the
waste system had high STP values.
34 Sevier Partial Clean-Out
The clean-out was completed in July of 2002. A contractor was hired to accomplish the
task. The farmer reported that 700,000 gallons of solids were removed from the ponds
and land applied according to the clean-out plan. Some solids were left due to an
insufficient volume of water to mix with the holding pond contents for pumping and
removal.
88 Sevier Clean-Out Not
Required
The waste storage structure consist of an anaerobic lagoon. The structure was in good
shape without a large accumulation of solids. An unfavorable N:P ratio of 1:1.2 was
noted in the solids contained within the lagoon.
95 Sevier Clean-Out Not
Required
The waste storage structure consist of an anaerobic lagoon. The structure was in good
shape without a large accumulation of solids. However, an unfavorable N:P ratio of
1:1.2 was noted in the solids contained within the lagoon.
98 Sevier Clean-Out Not
Required
The waste storage structure consist of an anaerobic lagoon. The structure was in good
shape without a large accumulation of solids. However, an unfavorable N:P ratio of 1:2
was noted in the solids contained within the lagoon.
25 Sevier Partial Clean-Out
The structure had a considerable solids content and the surface area (1.78 acres) and
waste volume (3.158 million gallons) made for a formidable clean-out task. Standard
agitation equipment is ineffective due to pond size. The farmer irrigated gray water and
hired a contractor to remove $10,000 worth of solid.
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32
Farm
Number County Clean-Out Status Summary of Clean-Out Activity
61 Sevier Complete
The farmer added 60 acres to the permit. Considerable solids accumulation was found in
the pond in which an N:P ratio of 1:1.1 was noted. The clean-out was begun in the
summer of 2001 and completed in the summer of 2002.
86 Conway Complete
The facility has a large holding pond with just under an acre (.92 acre) of surface area.
Equipment access to half of the holding pond was difficult due to narrow levee crest and
steep side slopes.
15 Conway Complete
The farmer opted for an incremental clean-out in order to spread out the expense. The
holding pond was built by constructing an earthen dam across a draw. It has a relatively
large surface area (.75 acre) with steep inside slopes and a narrow dam crest which
effectively restricts equipment access to most of the structure. The farmer focused on
removing the solids in the settling basins and the solids effecting flush pump operation in
the holding pond. Although 708 acres are permitted, 350 acres are more than 10 miles
from the barn complex effectively rendering this land unusable due to excessive hauling
expense . Of the remaining land, 67 acres had high STP levels. A considerable quantity
of solids remain in the holding pond.
51 Monroe Incomplete
The holding pond is relatively large with approximately an acre of surface area.
Equipment access to half of the structure is limited due to the close proximity of the
pond to the barns and a drainage ditch. The farmer did not clean-out due to family
medical problems, low commodity prices and high clean-out cost.
130 Pope Complete
The ponds were cleaned out in July of 2000. Equipment access to the settling basin and
two sides of the holding pond are difficult due to proximity to the barns. In addition, a
narrow levy crest with steep inside and outside slopes further limits access to the ponds
with waste management equipment. The farmer added 42 acres of land to his permit and
avoided application to approximately 66 acres due to high STP levels. The clean-out
was accomplished in split applications over the course of a growing season to intensively
managed bermuda grass hay.
163 Pope Complete
The ponds were observed to be empty in October 2001. Although the holding pond does
not have a large surface area, it is deep with narrow levy crest and steep inside and
outside slopes making equipment access difficult. The farmer added 31 acres to the
permit. The clean-out was accomplished in a late summer and spring application to 113
acres.
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33
Farm
Number County Clean-Out Status Summary of Clean-Out Activity
16 Newton Complete
The ponds were observed to be empty in August 2000. Access to the holding pond was
very difficult due to a narrow levee crest and steep side slopes. The farmer added 60
acres to his permit. The clean-out was accomplished in a mid growing season
application to approximately 42 acres. Due to high STP levels, manure application to 18
acres of permitted land was avoided.
19 Newton Complete
The ponds were observed to be empty in May of 2000. The ponds did not have a large
surface area however equipment access was difficult due to steep uphill slopes and steep
levy side slopes with a narrow crest. Manure application to 17 acres was avoided due to
high STP levels. Waste from the clean-out was applied to 35 acres, 24 of which is
intensively managed for bermuda grass hay production.
25 Searcy Complete
The ponds were observed to be empty in August of 1999. Equipment access to 3 sides of
the holding pond is restricted by a pasture fence. Manure application to 9 acres was
avoided due to high STP values.
37 Searcy Complete
The holding pond at the dairy farm was observed to be empty in August 1999.
Equipment access was hindered by narrow levy crest with steep inside and outside
slopes.
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34
Returning to Facilities After Clean-Out
One facility that received
clean-out planning was
revisited two consecutive
years following the initial
clean-out of accumulated
solids. The difference in the
mass of nutrients in the
holding pond of that facility
one year subsequent to the
initial pond clean-out was
dramatic. Figure 8 indicates
that the concentrations of
nitrogen and phosphorus are
nearly three times less in a
pond receiving annual clean-
outs when compared to the
concentrations of nutrients in
the pond before the initial
clean-out was conducted.
Proper maintenance and annual clean-outs of LAWMS as prescribed by facility permits results in
a liquid manure with nutrients that are less concentrated and less likely to result in loss of
phosphorus to surface waters. Slight year to year variations of average nutrient concentrations in
annually maintained LAWMS should be expected due to variations in precipitation that may
dilute the liquid manure.
Analysis of manure samples
Figure 8. Nutrient Concentrations in Holding Ponds Prior to and
Following Annual Manure Solids Removal
Figure 9. Concentration of Nutrients Found in Various Phases of
LAWMS Manure Storage
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35
Over the course of the Land
Application Project, numerous
manure samples were collected
and analyzed in order to assist
in the development of
LAWMS clean-out plans. The
raw analysis data for samples
collected during the course of
the project can be found in
Appendix G. Figure 9 shows
the average concentrations of
various components of manure
found in LAWMS. The
components shown in the
graph include: the Asolids@
found at the bottom of the
pond, the Acomposite@ or the
average of the holding pond if it
were completely mixed, the Agrey@ water at the top layer of the pond, and the composite of the
Asettling basin@ if the settling basin were completely mixed. The information in Figure 9
depicts the differences in nutrient concentrations for the various stratified components of a
LAWMS. As expected, nutrient concentrations in the solid materials was much higher than the
concentrations found in grey water and, as solids accumulate in LAWMS, the mass of nutrients
also increased. The average concentration of nitrogen and phosphorus for composite samples
collected from the12 facilities that utilized a holding pond for manure storage was 30 and 28
lb/1000 gal respectively. Figure 10 shows the concentrations of other analytes for holding pond
composite samples that were collected and analyzed. Samples of manure solids were collected
from the bottom of the ponds of twelve facilities.
Both nitrogen and phosphorus concentrations averaged 81 lb/1000 gal. Figure 11 displays the
concentrations of other analytes in the high solids content layer of swine liquid manure holding
ponds. Comparing concentrations of sulfate from the composite average and solids average
shows an increase of nearly 4 times, from 4 to 15 lb/1000 gal. Higher concentrations of sulfates
in manure solids indicates that as
solids accumulate over time, the
potential for air quality
degradation both in-situ and
during land application may
increase. Removal of manure
solids on a regular basis would
reduce the potential for air quality
degradation at swine facilities.
Grey water samples were not
collected as frequently as samples
of other components. Only five
grey water samples were collected
Figure 10. Concentration of Analytes in Composite Samples
Collected From Holding Ponds
Figure 11. Concentration of Analytes in Accumulated Manure
Solids Samples Collected From Holding Ponds
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36
over the life of the project. This was primarily due to the fact that grey water concentrations
were generally not required to develop an effective clean-out plan. To reduce time and expense
of analysis, grey water samples were not collected frequently. For the five samples that were
collected, the average concentration of nitrogen and phosphorus for the grey water samples was
5 and 1 lb/1000 gal respectively. These numbers are similar in scale to the average
concentrations submitted by producers to the state in the Regulation No. 5 annual reporting
process. The similarity between the grey water analysis and the concentrations reported in
Regulation No. 5 reports indicates that many producers are not effectively mixing the contents of
the LAWMS prior to the land application of the liquid manure.
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37
VI. Clean-Out Case Study
In order to insure that all of the issues and concerns associated with a waste system clean-out
plan development and implementation were addressed, a farm was selected as a test case. The
goal of the test case was to insure that waste volume and nutrient content predictions were
accurate prior to beginning work with other farms. Another important objective was to develop a
standard process for addressing problems common to many farms in the swine producing areas
of the state. The farm selected for the test case was also used in the aluminum chloride
demonstration component of the project which will be discussed later in this report.
The clean out test case farm was a typical 10 year old facility utilizing total confinement of
animals and built during a period of rapid swine industry growth in Arkansas in the late 1980's
and early 1990's. The farm is located in the Ozark Mountains of the north-central part of the
state. It is a contract growing operation and was originally built as a 240 sow, farrowing-nursery
operation in which pigs produced on the farm were raised to 40 pounds at which time they were
shipped to a finishing operation. During the clean out planning process the farm was being
converted to a 360 sow farrow-to-wean operation in which the pigs are shipped off site to a
nursery operation when weaned at 10 pounds. Both operations utilize total confinement of sows
within the barns.
The waste system consisted of a settling basin and holding pond with a recycle flush system.
Water pumped from the holding pond is used to flush the length of each barn where it collects
animal waste and transports it to the settling basin. Solids remain in the settling basin while gray
water overflows to the holding pond. Surplus liquid and animal waste is periodically land
applied with a gasoline powered pump and several hundred feet of 3 inch plastic line through an
irrigation gun. In addition, a tractor pulled 1000 gallon capacity honey wagon was available for
land applying manure to the more remote fields. The farm had approximately 84 acres
permitted for land application, of which, 19 acres nearest to the barn complex had STP levels
greater than 300 pounds per acre (Figure 6). The farmer was advised to avoid application to this
area. Additionally, 20 acres of permitted land was roughly 20 miles from the barn complex, too
far to be feasible for use as land application acreage. Of the permitted land, 45 acres was
suitable for land application.
As with most farms, permit required freeboard levels were maintained by pumping the ponds
from the top. The farmer did not own agitation equipment and did not mechanically mix the
pond contents during routine land application activities, consequently a considerable volume of
solids had accumulated. Another factor contributing to solids accumulation at this farm was the
recycle flush pump intake configuration. Rather than floating the intake so that water could be
pumped over a wide range of pond levels, it was fixed to a post. This required the pond to be
maintained at a minimum level in order to operate the recycle flush system. This is not an
uncommon flush pump configuration at farms in Arkansas and contributes significantly to the
solids accumulation phenomenon. If the farmer drops the pond level below the recycle flush
pump intake, the barns cannot be properly cleaned until the liquid level recovers. During the
time interval in which the barns are not flushed, manure must be scraped and removed from the
barns by hand or allowed to accumulate which creates sanitation concerns.
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38
Pond measurements and samples of the waste system were collected on July 15, 1999 utilizing
the standard sampling methodology developed for the project and included in Appendix B of this
report. From this information the manure volume was estimated to be 225,000 gallons with the
total mass of nutrients estimated to be 10,500 pounds and 10,000 pounds for N and P
respectively. The estimated waste system volume turned out to be 3.6 percent higher than the
actual volume of waste removed during clean-out operations. This is considered to be a very
good pond volume estimate. Based upon the initial waste system characterization it was evident
that there was insufficient permitted land application acreage available for the clean out,
particularly if manure was to be applied at a reduced N based rate and the 19 acres exceeding
300 pounds per acre STP were to be avoided. Fortunately, the farm is located within a
geographical area of low confined animal operation density and the cooperating farmer had no
trouble in locating suitable additional acreage near the farm. Project staff assisted the farmer in
requesting one time land application authorization from the State Permits Branch of ADEQ for a
12 acre and 220 acre tracts of land. The request was approved conditionally, based upon the
tracts being added to the list of land application sites by a formal permit modification within a
specified time frame.
The waste system clean out took place over four days in early August of 1999. A waste
management contractor was hired and project personnel were on site to observe and collect waste
samples. Activities related to the Aluminum Chloride Demonstration were conducted
concurrently and are discussed later in this report.
Considerable differences in predicted and measured nutrient concentrations in LAWMS were
noted by project staff in the Swine Project as well as the Solids Survey. Based upon a
Regulation No. 5 requirement, each
operator of a permitted LAWMS
must collect a manure sample
annually, which the Cooperative
Extension Service laboratory
analyzes for nutrient
concentrations, and submit a copy
of the analysis to the State Permits
Branch. An evaluation of two years
of data for all facilities in the state
by project staff indicated nutrient
concentrations for virtually all
samples submitted were more
typical of the surficial gray water
layer of a non-maintained stratified
pond. Nutrient values for the
typical waste analysis submitted
were also noted to be considerably
lower than predicted values in individual facility Waste Management Plans (WMP).
Furthermore, both the waste analysis reports and the WMP predicted nutrient concentrations
were considerably lower than values obtained from composite samples collected using
Figure 12. Comparison of Nutrient Concentrations From Various
Clean-Out Planning Data Sources
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39
methodology developed in the Swine Project. Figure 12 clearly depicts the wide-ranging
differences between the concentrations of total N and P for which a clean-out plan for the facility
could be based. If the clean-out plan were to be based upon nutrient values derived from the
Regulation No. 5 waste analysis, the plan would underestimate the nutrient mass in the ponds,
consequently nutrients would have been over applied by approximately 6.5 times. For the
particular facility in the example, that would have resulted in an application rate of 900 lb
N/acre. Over application of manure by this magnitude could have serious deleterious effects on
water quality as well as adverse health effects on grazing ruminants from nitrogen toxicity. Even
utilizing the WMP derived nutrient values would have resulted in an over application by 2.8 and
3.3 times for N and P respectively. That is not to say the WMP was developed incorrectly. If
the farmer had removed the solids annually the concentration of nutrients in the pond would
most likely mimic what is found in the WMP. In fact, review of Figure 8 shows that for the
facility that was revisited after successive clean-outs, nutrient concentrations in the holding pond
were found to be similar to the values predicted in the WMP for the facility of interest in the case
study. Although the facilities are very similar, slight variations in average nutrient concentration
from year to year should be expected due to differences in annual precipitation.
Figure 13. Houle "AgiSprayer" Equipment Used For Agitation
During Pond Clean-Out Process
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40
The manure that was land
applied during the clean-out
process was sampled to
determine if the composite
samples collected using the
described methodology were
accurate predictors of the
concentrations of nutrients that
would eventually be land
applied. This was done by
collecting samples from the 3150
gallon tank spreader that was
used for land application of the
pond contents. The pond was
thoroughly agitated for
approximately 1 hour prior to
beginning the land application
process. Agitation was
accomplished using a PTO and
hydraulically driven Houle AAgiSprayer@ shown in Figure 13. Samples were collected from
every 7th
tank load for the first 22 loads and then every 5th
load for the remaining land applied
tank loads. The samples that were collected were sent to the ADEQ laboratory for analysis. The
results of each of the analyses were averaged to arrive at a value for the average concentration
nutrients that were actually land applied by tank spreader. Figure 14 shows a comparison of the
concentration of nutrients predicted by the composite sample collection methodology to the
concentration of nutrients in the land applied liquid manure. Utilizing the composite sample
analysis resulted in an under-estimation of 8% for total nitrogen and an 16% over-estimation of
total phosphorus when compared to the actual concentration of nutrients applied during the
clean-out process. Although there is some difference in the predicted and measured
concentrations, composite sampling resulted in a far superior method of prediction when
compared to annually reported or WMP concentrations. Additionally, in this particular case, the
collection of the composite sample resulted in a conservative nutrient estimate that would further
reduce phosphorus runoff in storm water and accumulation in receiving soils.
Figure 14. Comparison of Composite Sample Results to Samples
Collected From Land Application Equipment
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41
All the correct and proper
planning that goes into a
LAWMS clean-out plan can
easily be undone during the
actual land application process.
In the case study, project
planners developed a plan that
the cooperating producer had
reviewed and agreed to
implement. The plan called for
application of the manure to
pastures with low STP
concentrations (less than 300 lb
P/ac) and at one-half the
permitted nitrogen application
rate. The planned application
rate was to be 75 lb N/ac. The producer went through the extra effort of obtaining additional
land for the clean-out to be executed properly. The project staff had experience with the
contractor hired to perform the pond clean-out and using a map of the facility, clearly explained
to the contractor where the manure was to be land applied and what the application rate should
be. The contractor did as was instructed and did not apply to pastures that had high STP values.
However, even with what were
supposedly clear instructions on
proper application rates, many
pastures ended up receiving the
full application rate. The mistake
was discovered during the clean-
out process and quickly rectified.
However, this occurrence shows
the importance of a responsible
person observing and paying
attention to the contractor
providing the clean-out services to
insure that the clean-out is
performed in a way that is
consistent with the developed
clean-out plan.
Tank Spreader Sampling
As described in the previous section, the tank spreader used for land application of manure being
cleaned out was sampled every 7th
tank load for the first 22 loads and then every 5th
load for the
remaining land applied tank loads. Samples were also collected and analyzed every 7 loads from
the tank spreader used during a clean-out procedure at another participating facility. The
observed changes in nutrient concentrations as a pond clean-out progresses are shown in Figures
15 and 16. Nitrogen and phosphorus concentrations increased by 54 and 42 percent respectively
Figure 15. Nutrient Concentration Change in Samples collected From
Tank Spreader During Clean-Out at Case-Study Facility
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42
from the first collected sample to the final sample collected at the case-study facility. At the
other facility where tank sampling was conducted, the concentration of nitrogen and phosphorus
increased 63% and 45% from the first to the last sample that was collected from the tank
spreader. The observed changes in concentrations during the clean-out process will be the most
dramatic as agitation efficiency decreases. Less effective agitation will result in a mixture of
liquid manure that is not homogeneous and would result in changes in nutrient concentrations as
the clean-out progresses. This information emphasizes the point that effective agitation is
important in achieving a uniform mixture for land application and that during the planning of a
pond clean-out, considerations could be made to incorporate the changing concentrations over
time and to adjust application rates accordingly.
Figure 16 Nutrient Concentration Change in Samples Collected From
Tank Spreader During Clean-Out at a Second Participating Facility
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43
VII. Aluminum Chloride Demonstration and Economic Alternatives
An important component of this project involved working with the University of Arkansas,
Fayetteville Campus, the APPA and a cooperating farmer to demonstrate the effectiveness of
treating swine manure slurry with aluminum chloride prior to land application. This project was
initiated in an effort to reduce soluble P concentrations in storm water runoff following land
application of liquid swine manure. Aluminum chloride has been used in municipal and
industrial waste water treatment applications for decades and could prove to be a valuable tool in
reducing agriculture related non-point source pollution, particularly in watersheds with a high
swine farm density.
The evaluation of the manure treatment methods was conducted at the same participating facility
that was used as a test planning case in Section VI. A description of the facility can be found in
Section VI.
Figure 177. Addition of Aluminum Chloride to Holding Pond
The goal of this portion of the project was to treat the contents of a holding pond with aluminum
chloride in an effort immobilize soluble reactive phosphorus (SRP) prior to land application.
The manure in the holding pond was to be treated in-situ because the condition of the holding
pond, having accumulated manure solids, represented a common scenario at Arkansas swine
production facilities. In order to quantify and characterize the pond contents for the aluminum
chloride treatment as well as to develop a clean-out and land application plan, the ponds were
sampled utilizing the pond sampling methodology described in Section IV. However, in addition
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44
to composite samples of both ponds, discreet samples were collected at one foot intervals. From
the analytical results, the mass of P and N were estimated and the nutrient concentration of each
distinct strata within the structures was determined.
Approximately two weeks after the initial sampling event, project workers arranged for a
contractor to be on site to mechanically mix the holding pond so that additional samples could be
collected. This was done in order to allow the U of A to conduct laboratory bench test to
determine the quantity of aluminum chloride required to effectively treat the pond contents. In
addition, the mixing capability of the agitation equipment was evaluated at this time. The pond
was mixed with a Houle Agisprayer powered by a 100 horse power tractor. The Agisprayer is
equipped with a power take off (PTO) driven propeller agitator with a sludge pump and spraying
capability for directing a high pressure stream of liquid waste at compacted solids. After
mechanically mixing the pond contents for approximately four hours, two 10 liter composite
samples were collected and delivered to the U of A Department of Agronomy laboratory.
Results of the bench tests indicated that the quantity of aluminum chloride required to treat the
entire volume of waste in the holding pond was beyond what could practically be transported to
the site. Therefore, it was decided that approximately half of the pond contents would be
removed and land applied prior to adding aluminum chloride. The pond was mechanically
mixed and land application operations began in early August 1999. Approximately half the pond
contents were removed and land applied with a 3150 gallon tank spreader.
Prior to treating the remaining liquid manure in the pond with the aluminum chloride, a 400
gallon sample of uniformly mixed manure (untreated) was collected to be used by the U of A on
rainfall simulation test plots fertilized with untreated manure. Land application activities ceased
while the aluminum chloride was blended into the pond. A two inch PVC pipe was extended
from near the propellor of the AgiSprayer to the trailer holding four 275 gallon containers of
treatment chemical (Figure 17). As the pond contents were mechanically mixed the aluminum
chloride was added, by gravity flow, and blended into the pond as thoroughly as possible. One-
half of the total volume of aluminum chloride was added to the pond and then the equipment was
moved to the other end of the pond where the remaining aluminum chloride was added. This
was done to improve the distribution of aluminum chloride throughout the liquid manure.
Following uniform mixing, land application activities were resumed and a 15 gallon sample of
the treated waste was collected after each 5 tank spreader loads (17,500 gallon intervals) and
composited into 400 gallon tanks. This treated manure was utilized on the U of A rainfall
simulation test plots fertilized with treated manure.
The report produced by the University of Arkansas Department of Agronomy on demonstrating
the effectiveness of adding aluminum chloride to liquid swine manure in order to reduce SRP
runoff has been inserted into the text of this report in it=s entirety.
University of Arkansas Report on Alum Addition
Introduction The swine industry today contends with two significant issues, odor and phosphorus (P)
runoff from agricultural land fertilized with swine manure. Even though the number of poultry
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45
producers exceed that of swine producers, more complaints associated with odor are issued to
swine producers. Fields receiving animal manure applications are under great scrutiny due to
alleged P inputs into water systems. Hence, alternative management practices may be necessary
to reduce potential odor and P runoff problems.
Ammonia (NH3) is one of the primary components odor from swine facilities. Conchal
atrophy (Drummond et al., 1981) and atrophic rhinitis (Robertson et al., 1990) are respiratory
ailments associated with high NH3 levels. Ammonia not only impacts swine, but also people
working in swine rearing facilities houses. Donham (1996) reported that 50% of the people
working in poultry houses had serious upper respiratory problems.
Phosphorus runoff from agricultural lands fertilized with animal manures is believed to
play an important role in eutrophication of nearby water bodies. As much as 90% of the P in
runoff from pastures is in the soluble form (Edwards and Daniel, 1993). Soluble reactive P
(SRP) is the most readily available form of P for algal uptake (Sonzongi et al., 1982). Many
state and federal agencies are regulating animal manure applications due to P runoff associated
with high soil test P levels and annual manure applications.
Research has shown that the addition of aluminum sulfate (alum) to poultry litter reduced
ammonia volatilization by 99% compared to normal litter (Moore et al., 1996). Alum-treated
litter has also been shown to reduce P runoff by 87% when compared to untreated litter (Shreve
et al., 1995). Since swine manure is normally a liquid, alternatives to land application such as
composting, pelletizing and transporting are simply not feasible. Therefore, chemical
precipitations of P in swine manure seems to be a feasible solution.
Smith et al. (2001) found that alum and aluminum chloride additions to swine manure
resulted in 84% reductions in SRP runoff concentrations. Although alum can be used to reduce
soluble P and P runoff from pastures receiving swine manure, aluminum chloride is probably a
better choice. This is due to concerns of hydrogen sulfide gas formation in certain situations
with alum additions. Production of hydrogen sulfide gas will not occur with the addition of
aluminum chloride. Smith et al. (2001) concluded that treating swine manure with aluminum
chloride could result in significant reduction in non-point source P runoff from fields fertilized
with swine manure.
All confined animal operations in the state, which utilize a Liquid Animal Waste
Management System, must be permitted by the Arkansas Department of Environmental Quality
(ADEQ) under Regulation No. 5. An important component of each liquid waste system are the
storage structures typically consisting of earthen ponds. Most waste system ponds in the state
are designed for a minimum storage capacity of 120 days of waste water and solids anticipated
from the number of animals confined by the facility. Waste is held in storage until it can be land
applied as a fertilizer, typically to forage crops.
In the fall of 1997, ADEQ Environmental Preservation Division staff conducted a state
wide survey of swine facility waste systems. During this survey, 40 of the approximately 400
swine facilities in the state were randomly selected for sampling and waste characterization.
Van Eps et al. (1998) reported that 52% of the holding ponds sampled were determined to have
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46
severe solids accumulation problems. An accumulation of nutrients, including soluble P, was
also found as a result of solid accumulation. In order to reduce waste system related problems
associated with accumulation of solids and the resultant loss of storage capacity, farmers are
encouraged to clean-out their ponds. The waste from these holding ponds will then be land
applied to nearby pastureland. Concerns could result as the sludge is high in nutrients,
particularly P, which could lead to water quality degradation. Smith et al. (2001) found success
in reducing P runoff from plots fertilized with swine flush water treated with aluminum chloride
and aluminum sulfate .However, no studies have observed the effect of aluminum chloride
treatments to swine manure in situ. The objective of this study was to determine the effect of
aluminum chloride on P runoff from swine manure treated in situ.
Methods and Materials Runoff studies were conducted on 24 small plots (1.52 x 6.10 m) cropped to tall fescue on
a Captina silt loam soil (fine-silty, siliceous, mesic Typic Fragiudult) at the University of
Arkansas Agricultural Research Station in Fayetteville, Arkansas. The plots have a 5% slope and
are hydrologically isolated from surrounding land with 15 cm metal borders (inserted so that
approximately 5 cm of the strips were exposed) on three sides. An aluminum collection trough is
located at the downslope edge. Beginning in June of 1999, rainfall simulation studies were
conducted to determine the effects of the following treatments on P runoff: 1) untreated swine
manure (control); 2) swine manure treated with AlCl3 (in situ); 3) swine manure treated with
AlCl3 at the University of Arkansas; and 4)swine manure treated with AlCl3 plus lime at the
University of Arkansas.
The swine manure was collected from a lagoon undergoing total clean out (solids being
removed) near Witt Springs in Searcy County, Arkansas. Initially, the lagoon was agitated for a
minimum of four hours utilizing a Houle Agisprayer powered by a 100 horsepower tractor. After
the first mixing, 500 gallons of untreated waste was collected as the control sample. Thereafter,
1100 gallons of liquid AlCl3 was added to the lagoon as agitation continued. A 15 gallon sample
of the treated waste was then collected from every fifth 3500 gallon Ahoney wagon@ load and
composited into a separate 400 gallon tank. This represented the manure treated with AlCl3 in
situ. Once samples were returned to the University of Arkansas Agricultural Research Center,
100 gallons of the untreated waste was separated for treatment. Treatments 3 and 4 were then
applied at appropriate rates.
Swine manure from the previously discussed treatments was uniformly land applied to
runoff plots as a P base loading rate roughly equivalent to 112 kg P ha-1
(100 lb ac-1
). A 250 ml
subsample of manure applied to each plot was taken for analysis of soluble reactive P (SRP) and
total P. Swine manure was collected in 250 ml centrifuge tubes in situ and placed directly on a
mechanical shaker upon return to the laboratory. The sample was then centrifuged at 8,000
RPM for 20 minutes and filtered through a 0.45 μm and acidified to pH 2 with HCl for SRP
analysis. Soluble reactive P was determined colorimetrically using the automated ascorbic
reduction method (APHA, 1992). Total P was determined using a spectro Model D ICP after
digestion with nitric acid.
After manure application, rainfall simulators were used to provide a 5 cm hr-1
storm
event sufficient in length to cause 30 minutes of continuous runoff. Runoff samples were
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47
collected at 2.5, 7.5, 12.5, 17.5, 22.5, and 27.5 minutes after initial runoff. The six samples from
each plot were composited based on flow rates at the time of sampling. Composited runoff
samples were filtered through a 0.45 μm membrane and acidified to pH 2 with concentrated
HCL. Soluble reactive P (SRP) concentrations in the runoff water were determined
colorimetrically on the filtered, acidified samples using the automated ascorbic acid reduction
method (APHA, 1992).
Results and Discussion Mean SRP concentrations in the manure applied were 146, 86.0, 99.6, and 45.2 mg P L
-1
for treatments 1-4, respectively (Figure 1). Untreated swine manure had significantly higher
SRP concentrations among all treatments. All AlCl3 treatments resulted in significantly lower
SRP concentrations. AlCl3/lime additions to swine manure resulted in significantly lower SRP
concentrations than all other treatments. The SRP concentrations in the manure treated in the
lagoon and manure treated at the experiment station with a similar rate were significantly
different. However, the concentrations did not vary greatly from each other. This shows that the
lagoon could have been treated at a rate greater than 1% (AlCl3, v/v), which would result in
lower SRP concentrations. As seen in Smith et al. (2001), AlCl3 additions to swine manure does
lower the SRP concentrations in the swine manure.
Soluble reactive P concentrations for the first runoff event were 29.7, 26.3, 23.4, and
21.3 mg P L-1
for treatments 1-4, respectively (Figure 2). Significantly higher SRP
concentrations in the runoff water found from plots receiving untreated manure than those
receiving manure treated at the experiment station. The lowest P runoff was in the AlCl3/lime
treatment, which also had the lowest manure P solubility. Likewise, the untreated manure
resulted in higher SRP concentrations in the manure and runoff water.
A second runoff event occurred one week after the first runoff event. For the second
runoff event, AlCl3/lime amendments resulted in the lowest SRP runoff concentrations (Figure 3).
Runoff SRP concentrations were significantly lower from plots receiving AlCl3/lime amended
manure than plots receiving unamended manure and manure amended in the lagoon. All runoff
concentrations were lower from the second runoff event than the first runoff event.
Rainfall simulations also conducted 14 and 16 days after the first runoff event occurred.
No significant differences were found among treatments for both events (Figure 4 and 5). As
seen on earlier runoff events, higher SRP concentrations in the runoff water were from plots
receiving unamended manure. Once again, AlCl3/lime amended manure resulted in the lowest
SRP runoff concentrations. As found by DeLaune et al.(2000), higher applications of soluble P
resulted in higher SRP runoff concentrations.
Conclusions
Aluminum chloride additions to swine manure reduced manure P solubility and SRP
runoff concentrations. Aluminum chloride/lime additions to swine manure resulted in the lowest
manure P solubility and runoff SRP concentrations. This is due to the addition of lime to raise
the pH to ensure no Al become soluble, therefore allowing the precipitation of P. Aluminum
chloride additions to the lagoon resulted in significantly lower manure SRP concentrations than
the untreated manure and lower runoff SRP concentrations. These data indicate that addition of
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48
aluminum chloride to swine lagoons during clean-out can effectively reduce soluble P levels in
the manure. As a result of reducing manure P solubility, reduction in P runoff from pastures
fertilized with swine manure treated with aluminum chloride can be expected. Further studies
should be conducted to determine the effect of aluminum chloride additions in swine houses in
an attempt to reduce NH3 volatilization and soluble P in the manure. Therefore eliminating the
need to add aluminum chloride to lagoons during clean-out.
References
American Public Health Association. 1992. Standard methods for the examination of water and
wastewater. 18th
ed. APHA, Washington D.C.
DeLaune, P.B., P.A. Moore, Jr., and T.C. Daniel. 2000. Factors affecting phosphorus runoff
from pastures. pp. 51-60. In (J.A. Baaweber, ed.) 2000 proceedings Mississippi Water
Resources Conference. Miss. State Univ.
Donham, K.J. 1996. Air quality relationships to occupational health in the poultry industry. pp.
24-28. In (P.H. Patterson and J.P. Blake, eds.) Proc. 1996 National Poultry Waste
Management Symposium. Auburn University Printing Service, Auburn, AL.
Drummond, J.G., S.E. Curtis, R.C. Meyer, J. Simon, and H.W. Norton. 1981. Effects of
atmospheric ammonia on young pigs experimentally infected with Bordetella
bronchiseptica. American J. Vet. Res. 42:463-468.
Edwards, D.R. and T.C. Daniel. 1993. Effects of poultry litter application rate and rainfall
intensity on quality of runoff from fescuegrass plots. J. Environ. Qual. 22:361-365.
Moore, P.A., Jr., T.C. Daniel, and D.R. Edwards. 1999. Reducing phosphorus runoff and
improving poultry production with alum. Poultry Sci. 78:692-698.
Moore, P.A., Jr., T.C. Daniel, D.R. Edwards, and D.M. Miller. 1996. Evaluation of chemical
amendments to reduce ammonia volatilization from poultry litter. Poultry Science
75:315-320.
Moore, P.A., Jr., T.C. Daniel, D.R. Edwards, and D.M. Miller. 1995. Effect of chemical
amendments on ammonia volatilization from poultry litter. J. Environ. Qual. 24:293-300.
Robertson, J.F., D. Wilson, and W.J. Smith. 1990. Atrophic Rhinitis: The influence of the aerial
environment. British Soc. Animal Production 50:173-182.
Shreve, B.R., P.A. Moore, Jr., T.C. Daniel, D.R. Edwards, and D.M. Miller. 1995. Reduction of
phosphorus runoff from field-applied poultry litter using chemical amendments. J.
Environ. Qual. 24:106-111.
Smith, D.E., P.A. Moore, Jr., C.L. Griffis, T.C. Daniel, D.R. Edwards, and D.L. Boothe. 2001.
Effects of alum and aluminum chloride on phosphorus runoff from swine manure. J.
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Environ. Qual. 30:992-998.
Sonzongi, W.C., S.C. Chapra, D.E. Armstrong, and T.J. Logan. 1982. Bioavailability of
phosphorus inputs to lakes. J. Environ. Qual. 11:555-563.
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SR
P c
once
ntr
atio
n i
n m
anure
(m
g L
-1)
0
20
40
60
80
100
120
140
160
A
B
C
D
Control Trt. 1
AlCl3Trt. 3
AlCl3 (in situ)
Trt. 2
AlCl3/Lime
Trt. 4
Figure 1. Soluble reactive P concentrations in manure amended with aluminum chloride
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51
SR
P i
n R
un
off
Wat
er (
mg P
L-1
)
0
5
10
15
20
25
30
35
A
AB
BC
C
Control Trt.1
AlCl3 (in situ)
Trt. 2
AlCl3Trt. 3
AlCl3/Lime
Trt. 4
Figure 2. Soluble reactive P concentrations in runoff water from the first runoff event on
amended plots.
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52
SR
P c
on
cen
trat
ion
in
ru
no
ff w
ater
(m
g P
L-1
)
0
5
10
15
20
25
A
A
AB
B
Control Trt. 1
AlCl3 (in situ)
Trt. 2AlCl3Trt. 3
AlCl3/Lime
Trt. 4
Figure 3. Soluble reactive P concentrations in runoff water from the second runoff event on
amended plots
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53
SR
P c
once
ntr
atio
n i
n r
unoff
wat
er (
mg P
L-1
)
0
2
4
6
8
10
12
14
Control Trt. 1
AlCl3 (in situ)
Trt. 2
AlCl3Trt. 3
AlCl3/Lime
Trt. 4
Figure 4. Soluble reactive P concentrations in runoff water from the third runoff event on
amended plots
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54
SR
P c
once
ntr
atio
ns
in r
unoff
wat
er (
mg P
L-1
)_
0
2
4
6
8
10
12
Control Trt. 1
AlCl3 (in situ)
Trt. 2
AlCl3Trt. 3
AlCl3/Lime
Trt. 4
Figure 5. Soluble reactive P concentrations in runoff water from the fourth runoff event on
amended plot
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55
VIII. Conclusions
The Land Application of Accumulated Solids From Liquid Waste Systems Demonstration
Project was a success in that it has helped to raise producer, integrator, and government
awareness of manure solids accumulation issues and how they can be properly addressed. As
this project progressed, the interest in proper operation of swine liquid animal waste management
systems (LAWMS) has dramatically increased on the part of the swine industry and government
agencies charged with regulating and providing technical assistance to Arkansas swine farmers.
The interest in proper swine manure management generated by this and preceding projects has
helped to bring assistance to operators of facilities requiring LAWMS clean-outs in the form of
financial assistance for the execution of properly planned system clean-outs.
Through this project, the solids accumulation issue associated with LAWMS has been brought to
the attention of swine industry and government, unfortunately producer participation in the
project was less than hoped for. The reasons for the lack of farmer participation varied,
however, ultimate interest in cleaning-out swine LAWMS must come from the producer or be
driven by industry or legislation. Every LAWMS operator in the state was made aware of the
solids accumulation issue through multiple presentations at Regulation 5 training meetings and in
most cases farmers understand and have an interest in the issue. In addition to producer wariness
of government agencies and programs, the most likely reason for not wanting to participate in
obtaining a plan for a total pond clean-out was cost. Federal cost-share assistance for properly
planned LAWMS clean-outs will increase farmer interest in completely emptying out
accumulated solids from their systems.
Financial assistance for LAWMS clean-outs should be provided to farmers only if there is a plan
developed specifically for that facility that will be protective of water quality. The planning
criteria must take into account mass of accumulated nutrients, soil test phosphorus values,
reducing over-application of phosphorus by applying at one-half the nitrogen rate, potential
BMPs including pasture renovation and stormwater diversion, and continuous management of
the system after the clean-out has been completed.
At this time, the potential exists that permit holders of LAWMS will be required to document
and provide verification that the system has been cleaned-out every year as part of the annual
reporting process. If the requirement to document annual pond clean-outs comes to fruition, the
resources for providing proper planning and clean-out services will need to be developed in order
to accommodate the number of facilities that will require the initial pond clean-out of years
worth of accumulated manure solids.
An additional condition that has recently developed in Arkansas, is the announcement by a major
pork production integrator that the company will no longer contract with Arkansas pork
producers. The result of this action is that approximately 140 swine facilities will no longer be in
operation. Of the 140 facilities, many owners of those facilities will elect to close out their
permits. This will be another situation that will require additional resources to address the
number of facilities that will require manure solids clean-out planning. Failure to provide proper
planning and oversight will result in deleterious effects on water quality, especially in areas with
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56
high densities of swine production facilities.
A total of 18 farmers requested and received planning assistance through the framework set up in
this project. Each farmer received help in assessing the solids and nutrient accumulation status
within their LAWMS and were given recommendations on how to proceed in recovering the full
waste system storage capacity while achieving the greatest fertilizer benefit and protecting water
quality. Farmers that followed the recommendations in the farm specific plan reduced the
environmental impacts of their system by reducing the over-application of N and P as well as
reducing the potential for future pond discharges.
Many farmers had difficulty in immediately implementing the clean-out plan. This was
primarily due to insufficient monetary resources and a lack of available permitted land
application acreage to assimilate the mass of nutrients in storage. Future planning will need to
acknowledge that for most farms, a multi-year approach will be required to accomplish the task.
This will allow the farmer time to plan for the clean-out expense in his operating budget.
Another major hurdle in implementing the plans involved the amount of available land
application acreage. Of the 18 participating farms, 16 required additional acreage to accomplish
the task in a manner that satisfied project goals of applying the mass of nutrients at acceptable
environmental and agronomic rates. However, the regulatory framework for adding land
application acreage to a permit is by design difficult, time consuming and relatively expensive.
From an environmental stand point, the manure can be better assimilated by soil and cover crops
when spread over a greater area. In many ways, animal manure is a better soil amendment than
commercial fertilizer, however, regulatory restrictions and negative public attitudes serve to limit
more widespread use. The industry practice of concentrating large numbers of farms in relatively
small geographic areas has contributed to negative public perception of manure as a fertilizer and
has contributed greatly to contract grower difficulties in adequately managing manure. An
associated farm density issue is forest conversion to pasture in order to obtain more acreage on
which to land apply manure. Forested land can benefit farms by providing visual barriers, aid in
dispersing odors and associated gases and moderating seasonal temperature extremes. That
being said, farmers should be encouraged by all parties to utilize land that has already been
converted to pasture, rather than clearing additional forest merely to increase the available land
application acreage.
As farmers realize the benefits of accumulated manure solids removal, including less time spent
on system maintenance and greater fertilizer value derived from animal manure, and at the same
time, more resources become available for planning and financing clean-outs, the number of
clean-outs occurring in the future should increase significantly. System clean-outs in watersheds
that have a large number of facilities should be monitored to insure that the number of facilities
performing clean-outs during any one period do not exceed that capacity of the watershed to
assimilate the land applied nutrients. For example, in the Millwood Lake watershed, in the
southwest part of the state, there are approximately 100 swine facilities. If in the worst case, all
of those facilities were to perform a system clean-out at the same time, land applying hundreds
of thousands of pounds of nutrients, the potential exists for significant adverse effects on the
water quality of Millwood Lake, including algae bloom and low dissolved oxygen conditions.
The timing and number of LAWMS clean-outs should be monitored to avoid over-loading a
watershed with nutrients.
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Thorough planning is only half of the process for an environmentally responsible LAWMS
clean-out. As good as any plan may be, it is only as good as the person actually performing the
clean-out. Since most facilities do not have adequate equipment to carry out the mixing and
removal of accumulated solids, many operators will be utilizing contract pumping services.
Each clean-out that is conducted by contracted services should be monitored, at least in part, by a
person who is familiar with the plan for the LAWMS clean-out and the land application of
animal manures. It is foreseeable that unscrupulous service providers would not follow plans to
avoid spending the extra time required to land apply the liquid manure at rates specified in the
plan. Improper land application of the manure solids not only affects water quality, it affects the
producer by under utilizing the fertilizer value of the removed solids and causing phosphorus
accumulation in pastures that may result in those pastures becoming unsuitable for land
application of manure in the future. In addition, nitrogen toxicity to cattle consuming over-
fertilized forage could be a concern. Some method of accountability should be developed to
avoid improper land application practices by pump out services.
The use of Aluminum Chloride additions to swine manure showed effectiveness in reducing the
amount of soluble phosphorus in accumulated manure solids as well as reducing the amount of
soluble reactive phosphorus concentrations in simulated runoff conditions. Aluminum
chloride/lime additions to swine manure resulted in the lowest manure phosphorus solubility and
soluble reactive phosphorus concentrations in simulated stormwater runoff. The data collected
as part of this project indicate that addition of aluminum chloride to swine lagoons during clean-
out can effectively reduce soluble phosphorus levels in the manure. As a result of reducing the
quantity of soluble phosphorus during the clean-out, reductions in phosphorus runoff from
pastures fertilized with swine manure treated with aluminum chloride would be expected. An
amount of aluminum chloride equivalent to one percent of the volume of sludge was added to the
test LAWMS at a cost of approximately $2,000 for a relatively small system (200,000 gallons).
Although the addition of aluminum chloride did reduce the amount of soluble phosphorus in the
system, it is questionable as to whether or not this is a cost effective solution to reduce
phosphorus runoff. This treatment method could possibly be used as a last resort in situations
where a producer, that has high soil test phosphorus levels and has no viable means to obtain
additional acreage that is within a reasonable hauling distance from the facility, needs to perform
a system clean-out to continue operation or to complete a system closure. Further studies should
be conducted to determine the effect of aluminum chloride additions in swine houses in an
attempt to reduce ammonia volatilization and soluble phosphorus in the manure, eliminating the
need to add aluminum chloride to lagoons during clean-out.
The compilation of additional analytical data from properly sampled manure storage ponds at
cooperating farms has been a significant accomplishment of the project. Along with information
obtained through the Swine Project and the Solids Survey, this data forms an important base of
information that can be used in a variety of ways to improve waste system design, operation and
maintenance. The analytical data may find use in the future as a planning tool for LAWMS
clean-outs. For example, using the volume of solids present in a system, easily determined by
measuring the solids depth and using the storage pond design plans, the mass of nutrients may be
predicted by multiplying the average concentration of nutrients in manure solids collected during
this project by the volume of solids estimated to be in the pond of interest. The data collected
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through this project could provide much needed supplementary information for the design and
maintenance of LAWMS. The utility of the data that has been collected during the course of this
project illustrates the value this project has provided to taxpayers.
Until tools to estimate the quantity of nutrients contained in a LAWMS are available, accurate
pond sampling should be conducted utilizing a protocol similar to that described in this report. It
is unlikely that producers will have the resources to execute the type of sampling necessary for
accurate manure clean-out planning and resources, in the form of assistance from local
conservation districts, the Cooperative Extension Service or a private vendor will be required.
During the course of this project the concept of managing animal manure with forethought and
insight has been presented to a broad range of people involved in the pork production industry in
Arkansas. The ultimate success of this project can be evaluated in short and long term results.
In the short term, this project was able to assist a number of swine facilities address accumulated
swine manure solids in a cost-effective and environmentally responsible manner. In the long
term, the project has helped to generate an interest within agencies responsible in assisting the
small swine farmer that should perpetuate some of the ideas developed through the work of this
project. Ultimately, it is hoped that this project has helped to insure that small family farms can
remain viable and sustainable, maintaining diverse and vibrant rural economies, while protecting
water resources for years to come.
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References
1 U.S. Environmental Protection Agency, “1996 National Water Quality Inventory Report to Congress,”
Washington, D.C., 1998 2 Arkansas Department of Pollution Control & Ecology. 1992. Regulation No. 5 Liquid Animal Waste
Management Systems. Open File Report prepared pursuant to the Arkansas Water and AirPollution Control
Act (Act 472 of the Acts of Arkansas for 1949). 10 pp. 3 S. J. Formica, T. Morris, M. A. Van Eps, T. Kresse, M. Anderson, J. Giese, Using Data, Communication &
Education to Improve Swine Waste Management in the Buffalo River Watershed, from the proceedings of
the 2nd National Conference on Nonpoint Source Pollution Information & Education Programs, Chicago,
Il, May 15-17, 2001 4 USDA NRCS, Part 651 Agricultural Waste Management Field Handbook, Page 3-12, 1992
5 Reed, Benjamin, Effect of Pasture-Applied Swine Slurry on Runoff and Leachate Water Quality, University of
Arkansas, 1996 6 Van Eps, S. Formica, T. Kresse, A. Czarnomski, E. Van Schaik, J. Giese, T. Morris, from the proceedings of the
“International Conference on Agricultural Engineering” Oslo, Norway August 24 - 27, 1998 7 USDA NRCS, Part 651 Agricultural Waste Management Field Handbook, Page 4-12, 1992
8 ADEQ, Environmental Preservation Division, Sandi Formica, Principle Investigator, Administered by Arkansas
Soil and Water Conservation Commission, Project FY99-600