United States
Environmental Protection
Agency
Air and Radiation
(6202J)
EPA-430-F-98-055
Fall 1998
AgSTAR Digest
Inside...
AgSTAR: The Momentum Builds....1
Support Corner: AgSTAR Handbook
&FarmWare 3
Environmental Corner: Manure
Odors Raising a Stink 3
Showcase Corner
Craven Dairy 4
Martin Farm 5
Other Regional Activities Corner 6
New Participants 7
Odors go up in smoke. Installation Crew at first gas flare lighting, North Carolina.
AgSTAR has helped 6 Partner
Farms establish farm profit and
environmental centers with the
implementation ofbiogas
technology.
AgSTAR - The Momentum Builds
Over the past 18 months, six AgSTAR Partners have installed biogas recovery
systems and established new profit and environmental centers. This increase in
demand is the largest experienced since the mid-seventies. At least 10 more biogas
projects are in either planning or construction phases. See the Showcase and
Regional Corner for some specific farm details. By all indications 1999 will see even
larger demand based on AgSTAR program participation, hotline activity, feasibility
assessments, and project planning requests. The difference is that today commercial
systems are more reliable due to improved design, equipment, technical support, and
on-farm innovation. The best innovation we have seen is a complete retro-fit of 2
farrowing houses with heat mats at a 4,000-sow Partner farm. Biogas is used to heat
water in a boiler, which is circulated through the farrowing buildings.
These days, producers are selecting biogas technologies for multiple benefits, not
solely for energy production. Highest on the environmental benefit list is odor control.
All properly designed biogas systems substantially reduce odor. Several dedicated,
heated odor control digesters have been built in the last year. Basically an odor
control system collects biogas to fuel a boiler that in turn heats the digester. Heating a
digester decreases the volume needed to stabilize manure by speeding up the
biological (anaerobic) process that destroys odor-producing compounds in the manure.
Controlled high temperature decomposition in a digester will also reduce pathogens, a
major concern in water quality circles today. Dairy farms using scrape manure
collecfon benefit the most from heated digesters because the digested dairy manure
yields a high grade, weed and pathogen-free fiber that has commercial value in the
potting soil industry;digested dairy manure can be sold for $4-8/cubic yard.
(continued on page 2)
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AgSTAR-The Momentum Builds (continued)
Other AgSTAR Program highlights include:
ĞT Publication of National Interim Standards for Biogas
Systems by USDA's Natural Resource Conservation
Service (NRCS). The United States is now one of a few
countries to have such standards. Interim Practice
Standards on Covered Lagoons, Plug Flow and Complete
Mix Digesters can be found through the World Wide Web at
the following address: http:/www.ftw.nrcs.usda.gov.
>* An improved Memorandum of Understanding (MOU) for
Partners and Allies. The revised MOU is a simple one-page
voluntary agreement. In addition to emphasizing methane
recovery, the revised MOU recognizes the rnportance of
odor control and containment as a common environmental
AgSTAR goal because of increasing odor concerns
surrounding confined livestock facilities. Manure odor
management is discussed in the Environmental Comer on
page 3.
>* The Environmental Recognition component of the program.
Operating Partner Farms are awarded with a 25" x 12"
weather resistant, "EPA Partner Farm" sign that can be
displayed at farm entrances or along side other farm
insignia as at Craven Dairy (shown below). The AgSTAR
AgSTAR Partner, John Craven Jr., under his Partner Farm Sign
Program is also in the process of developing an
Environmental Steward certificate (illustrated in the
Showcase Comer, page 7). This 81/2 x 11 certificate is
suitable for framing and office display. As future Partner
farms go on-line, these symbols of environmental
recognition will be awarded bgether.
V The release of the AgSTAR Handbook including FarmWare
version 2.0. These tools are provided to assist in the
project development process based on technology choice,
operational ability, financial performance, and
environmental performance. See the Support Corner tor
details.
w Educational and training workshops. The most recent
workshop was held at the McKimmon Center in Raleigh,
North Carolina. Over 100 individuals - representing
producers, the agricultural industry, and state agricultural
agencies attended this workshop entitled "Methane
Recovery as a Cost Effective Environmental Opportunity for
Livestock Producers." This two-day event consisted of a
general overview of the AgSTAR Program, methane
recovery technologies, anaerobic biology, odor control,
water quality benefits, project development, and a field tour
of a commercial farm operating a covered lagoon biogas
system.
Stacy Gettier leads workshop participants on a tour of an on-farm
digester facility.
>* Expanded AgSTAR services to include cooperative or
centralized digester assessments. This manure
management strategy can provide opportunities for multiple
farms. Key factors influencing multiple farm feasibility are
herd sizes, manure management method and distance from
centralized digester site(s). Typically, digester sites are
located near some large energy user or electric utility
gateway. Site examples include feed mills, prisons,
rendering plants, substations, and other large users of heat
and electricity. Successful planning of centralized digesters
needs to include assessment of technical, financial,
environmental, and organizational elements to insure
successful long-term operation. The AgSTAR program has
completed two feasibility assessments. See Regional
Corner tor project details.
>V AgSTAR's Charter Farm Program is designed to assist in
the development of biogas technologies at commercial
livestock farms to demonstrate a variation of appropriate
technologies in key livestock producing states. Charter
Farms are available to livestock producers and others for
site visits on an appointment basis. Operational charter
farms already include dairy and swine farms in New York,
Pennsylvania, North Carolina, Illinois, Iowa and Oregon.
Charter Farms are also in construction or planning phases
in Colorado, California, Wisconsin and Minnesota. To make
arrangements for a farm visit to "kick the tires" and talk with
farm operators, or to apply as a Charter Farm candidate for
the 1999 construction season, call the AgSTAR Hotline at
1-800-95AgSTAR (1-800-952-4782).
2 AGSTAR DIGEST, FALL 1998
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AgSTAR Support Corner: AgSTAR Handbook & FarmWare
ftBW
AgSTAR is pleased to announce completion of the first
edition of the AgSTAR Handbook -- a comprehensive
"how-to" manual for developing biogas systems at
commercial farms throughout the United States. The
handbook provides a framework for farms that are
considering biogas production and use as a manure
management option. Using the handbook, a livestock
producer should be able to make a "go" or "no go" business
decision based on technology choice, operational ability, and
financial performance.
The handbook is
organized according
to the two stages of
biogas project
development:
feasibility assessment
and implementation.
The feasibility
assessment chapters
provide guidance on
screening for project
opportunities,
selecting a gas use
option, and
conducting site-
assessments to
identify technically
appropriate and cost-effective biogas recovery options. The
implementation chapters detail the steps in putting project
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Handbook
plans to work. Chapters include: selecting a developer;
obtaining project financing; complying with permitting
requirements; and designing and constructing the system.
The appendices of the handbook provide supporting
information including profiles of working digesters throughout
the U.S., NRCS and DOE contacts, the NRCS Interim
Practice Standards, and a list of industry contacts. In
addition, the appendices include installation disks and
manuals for the FarmWare and RateVision software
programs.
FarmWare is a user-friendly decision support computer
program that helps livestock producers determine whether a
methane recovery system can be profitably integrated into a
farm's existing or planned manure management system. The
software analyzes the financial performance of a methane
recovery system including the installation costs and benefits
from on-farm biogas use. FarmWare's reporting features
include a Summary Report that can be presented to potential
project financiers, contractors, and developers. RateVision
(version 1.0) is a software program designed to analyze
electricity rate schedules in relation to farm energy load
profiles. RateVision files can be imported into FarmWare
allowing for a detailed analysis of rate schedules in the
financial evaluation of a methane recovery system.
To order a copy of the AgSTAR Handbook and the
latest software programs, please call the AgSTAR Hotline at
1-800-95AgSTAR (1-800-952-4782).
Environmental Corner: Manure Odors Raising a Stink
anure-related odors have been attracting a great deal
of attention over the past few years, pitting the public
against the livestock producers. While the detection of
odor from livestock facilities varies from nose to nose, there
is considerable concern in some parts of the country that
manure-related odors will intensify with the continued trend
toward larger confined operations. In addition, many believe
that increased complaints regarding livestock odors are
inevitable as more people move to the country from cities to
suburbs.
Seasonal or chronic odor events from manure
management systems are indicative of a biological imbalance
within the system. Biological imbalances have many
potential causes, ranging from system design and sizing to
operational parameters. Regardless of the cause, the
resulting biological imbalance leads to only partial digestion
of the incoming waste stream. Inhibiting complete anaerobic
digestion and methane production allows intermediate
odorous compounds to form and escape into the surrounding
air potentially creating an odor. Designing and operating
manure management systems to promote methanogenic
biological activity can effectively reduce odorous compounds.
Methane bacteria degrade most odiferous organic
compounds producing methane and carbon dioxide, which
are odorless. Promoting anaerobic digestion and methane
production reduces odorous compound concentrations. In
addition, as a secondary benefit, methane is produced and
can then be used as an on-farm energy source.
Numerous studies have shown that digested manure
emits fewer odors than undigested manure. Pain et al.
(1990) quantified these results showing that up to 92% of the
odor associated with pig manure can be reduced by
anaerobic digestion. A summary of these results is shown in
the table below.
Odor concentration (odor units / m3 air) following spreading of pig slurries on grassland
Days in Storage
5
20
Farm A
Undigested
611
219
Digested (% Reduction)
142(77%)
18(92%)
FarmB
Undigested
1101
177
Digested (% Reduction)
223 (80%)
38 (79%)
Source: Pain, B.F., T.H. Misselbrook, and C.R. Clarkson. 1990. Odour and ammonia emissions following the
spreading of anaerobically digested pig slurry on grassland. Biol. Wastes 34: 259-267.
3 AGSTAR DIGEST, FALL 1998
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Showcase Corner: AgSTAR Partner Farms
Craven Farm
n December 1996, Jeff Craven, owner/operator of Craven
Farms in Cloverdale, Oregon, completed the installation of a
methane recovery system at his 650-cow freestall dairy. The
heated plug flow digester is an in-ground concrete structure that
measures 140 feet long, 30 feet wide, and 12 feet deep. The
digester is sized to treat manure from up to 1,000 milk cows,
and is covered by an inflatable and impermeable vinyl/plastic
material. Manure from the freestall barns is scraped once a day
into a collection tank for mixing. From the tank, the manure is
pumped into the digester.
Under the anaerobic conditions within the digester, the
manure is broken down to produce biogas and a nutrient-rich
effluent. The biogas, which is primarily methane, is collected
under the digester cover and pumped to two engine generator
sets, which started running on biogas January 1997. The
engines produce approximately 60 kW of electrical energy each.
All of the power produced is sold directly to the local utility
company as a source of green power for their generation mix.
To maintain an optimum digester temperature of
approximately 100°F, a network of water-heated pipes run
within the digester. The water is heated and recirculated into
the digester from a heat exchanger system used to cool the
engine generator sets. By Summer 1997, a plumbing system
Craven Farms'Plug Flow Digester.
The digester is 140 feet long.
will be installed so that hot water from the engine cooling system
can also be supplied to the milking parlor.
Once the manure has exited the digester, the solids
(Fibers) are separated from the liquid fraction. Separated solids
are sold to a local potting soil company and liquid effluent is
stored in a lagoon and land applied.
The methane recovery system at Craven Dairy has
produced revenues from electricity and fiber sales, while
providing the farm with an environmentally sound manure
management strategy.
"Aside from the environmental benefits, the
most important aspect of the digester for me
is that it is not nearly as complicated as I had
anticipated. It doesn't take a chemist to run
it. The system is simple and just a basic
biological process."
Jeff Craven, Little Nestucca Watershed,
Cloverdale, OR
Separated solids from Craven Farm's Plug Flow Digester
Craven Farms' engine room
4 AcSTAR DIGEST, FALL 1998
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Martin Farm
Harry and Debbie Martin are raising hogs in southern
Virginia at their 600 sow farrow to feeder pig hog facility.
They installed a covered anaerobic lagoon in fall 1993.
Unfortunately, the cover began to develop problems with gas
movement due to rainwater accumulation by the following
year. In 1996 the Martins requested technical support from
the Tennessee Valley Authority and the AgSTAR Charter
Farm Program to address the problems.
Rainwater accumulation on the previous cover at Martin Farm
The covered anaerobic lagoon, designed according to NRCS
Interim Standard No. 360 measures 124' by 124' by 22' deep.
The constant volume primary lagoon receives manure from
recycle flush tanks controlled by electronic timers. Buildings
are flushed 3-8 times/day with recycled water from a
secondary storage lagoon. Methane is produced as the liquid
waste stream is treated and is captured by a new modular
cover system, which floats on the surface of the primary
anaerobic lagoon. The treated effluent from the new covered
lagoon overflows into the storage lagoon and is used for
recycle water and seasonal fertilization.
Six new modular covers were developed with AgSTAR
technical assistance and factory-built by Engineered Textile
Products, of Mobile, AL, an AgSTAR Ally. The Martins
installed the lagoon covers, built from Seamens XR-5
material, over a three-day period April 1997.
"The technical support that I have
received through the AgSTAR
Program has been tremendous. First,
AgSTAR and the Tennessee Valley
Authority helped me replace the cover
on my lagoon. Now, AgSTAR is
helping me to maximize the benefits
of my biogas recovery system by
providing me with innovative
options."
Harry Martin, Martin Farm,
South Boston, VA
Methane generated in the covered lagoon digester is pumped
from under the floating cover with a vacuum pump. The
biogas flows from the digester, through a 550-foot
underground gas pipeline, into an engine generator. The
electrical production system consists of a 6 cylinder Chrysler
internal combustion engine coupled to a 25 kW, single-phase
induction generator. The unit generates in parallel with the
Virginia Power Company. The farm also has a low cost flare
to combust biogas during engine down times or periods of
excessive gas production. Biogas production varies between
8,000 and 14,000 ft3 per day, winter versus summer, due to
changes in lagoon temperature. Low winter gas production
limits engine use.
Providing heat to young piglets may be another benefit of the
Martin's methane recovery system. The Martins are
considering adapting the farrowing buildings to circulate hot
water produced by biogas and the engine system through
heat mats. This new technical development, first applied at a
Partner Farm in North Carolina, can increase financial returns
by reducing heat lamp and propane use for very little cost.
Direct use of heat as hot water appears to have a higher
value when used in farrowing crates than as previously used
in hot air applications.
The Martins are pleased with their methane recovery system.
It has helped them realize the benefits of controlling odor and
energy production, while being recognized for their
environmental stewardship through EPA's AgSTAR Program.
Installation of new cover at Martin Farm
To arrange a visit to Martin or
Craven Farms, contact the
AgSTAR Hotline at
1-800-95 AgSTAR
(1-800-952-4782)
5 AcSTAR DIGEST, FALL 1998
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Other Regional Activities Corner
n addition to the Craven and Martin Farm system, other
AgSTAR Partner farms are in either planning,
construction, or operational phases of their systems. A
few of these farms are highlighted below:
A A Dairy. Candor. NY. Bob Aman and his family have
over 500 milking cows with scraped freestall manure
collection. A plug flow digester was constructed (designed
for 1,000 cows) and started-up in fall of 1997. Biogas fuels
a boiler to heat the digester and provide heat to the dairy.
In early 1998 AA Dairy purchased and rebuilt a used 120
kW engine generator to produce electricity for farm use and
sale. The engine will provide 1,200 - 2,000 kWh of
electricity per day and is scheduled to go on-line by June
1998.
AA Dairy is separating digested solids for sale as fiber.
Separated liquids are stored for irrigation over cropland.
About his digester system, Bob Aman said, "We're really
excited about this ultimate recycling project."
Apex Pork, Galesbum, IL Glenn and Roger Saline own
and operate an 8,600 head finishing farm in west-central
Illinois. Nine buildings are equipped with pit recharge
manure collection. The storage basin has been prone to
seasonal odor events. Therefore, the farm installed a
prototype earthen, heated, "mixed" covered lagoon as part
of the farm's odor control strategy. After digestion,
deodorized effluent will flow to the storage basin prior to
land application. The digester will stabilize odor-producing
compounds and the additional heat entering the storage
lagoon should increase its biological performance over
time. The digester is complete and biogas production is
expected by early June. Gas is used in a boiler and flare
setup.
Example of AgSTAR Environmental Stewardship Certificate
Boland Farm. Williamsburg. IA. Gary Boland, a fourth
generation farmer, his wife Annette and four children live
about a mile from Williamsburg, Iowa, a growing town of
2,500 people. The Bolands operate two separate farm
sites, a finishing operation with a deep pit system and a
nursery with a pull plug and variable depth storage lagoon.
Since the Bolands built the lagoon two years ago they have
observed that the odor is stronger than they would like it to be.
Because the Bolands want to do everything possible to be good
neighbors, they installed a cover over the 150' by 130' lagoon to
capture and flare off methane for odor control. This system
does not require heat and is strictly for odor control. Wintertime
gas production will be almost zero. The cover was installed
early May 1998 and is operational. Total installed cost was
about $15,000.
Colorado Pork. Prowers. CO. Gary Swanson, General
Manager and part owner of Colorado Pork has begun
construction on a new 5,000 sow farrow to wean farm. All
buildings will operate on a pull plug manure handling system.
The farm's objective is to build an environmentally friendly waste
management system that is sustainable both from an energy
and nutrients recycling standpoint. A heated complete mix
digester for manure treatment is planned as an integral part of
the farm's manure management. The decision to build a
digester was made after comparing the cost of a 20-day heated
mixed digester to the cost of a lined treatment lagoon built to
meet NRCS guidelines. The mixed digester was found to be
almost the same cost as the lined treatment lagoon, if not less
expensive. There also is a return on investment from energy
cost savings, estimated at $67,000/year electric and
$29,000/year propane savings. Farm and digester construction
is scheduled for completion h December 1998. Digester start-
up should begin Fall 1999, when the farm is three quarters
populated.
Doe/man Dairy. Rochester. WA. Fred Colvin of Hank
Doelman Dairy, requested AgSTAR assistance to evaluate the
1,200 cow dairy and surrounding dairies for a centralized
digester system. The proposed project is under consideration
and may involve up to 6 dairies totaling 3,000 cows. The project
consists of 3 phases. The first phase will begin construction on
a 1,500 cow digester in Spring 1999. The conslruction of
additional digester modules during phases 2 and 3 is under
consideration to accommodate the remaining 1,500 cows.
Freund Dairy. East Canaan. CT. Matt and Ben Freund milk
200 cows in a freestall barn with tractor scrape manure
collection. The dairy pastures cows 16 hours a day from late
spring until early fall and cows are in the barn the rest of the
year. A small "drive-in" plug flow digester was completed and
started up in Fall 1997. The driving force behind the project was
the desire to upgrade the waste management system, better
manage the solids in the manure and produce usable
byproducts. Biogas is used as a fuel source in a boiler that
generates heat for the digester as well as for on-farm use.
Excess biogas not used in either application is flared. Freund
Dairy plans to use hot water to heat a greenhouse to supply
fresh produce for the family's farm store. The farm is
considering accepting some manure from neighbors during the
pasturing period to maintain constant gas production for fueling
a small co-generation unit.
6 AcSTAR DIGEST, FALL 1998
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