|
 |
|
Common
Manure Handling Systems
 Back to Pork Main Menu
Solid Manure
 |
 |
| Schematic of Solid Manure Systems |
Surface Application of Solid Manure |
| (Source: Purdue University) |
(Source: Purdue University)
|
Swine manure was historically handled as a solid, either deposited directly
by grazing animals, or collected in bedding placed on solid shelter floors
to absorb the urine. Pastured animals spread the manure over the land
as they grazed. Manure deposited on solid floors is typically stored where
it falls, with more bedding added as needed to maintain a dry floor. Liquid
drains away from the manure dropped on an outside lot and must be collected
in a storage, leaving the solid manure behind. The manure composts in
place somewhat and is removed every few months. Fertilizer value is recovered
by spreading on cropland to complete the nutrient cycle. Solid manure
is normally surface applied, but in some cases may be incorporated into
the soil with a farm tillage operation shortly after spreading. Composting
is another option for solid manure management.
Back to Top
Lot Runoff
 |
 |
| Options for Handling Manure from Open Lot |
Holding Pond for Runoff
from Outside Lot |
| (Source: Purdue University) |
(Source: Davis-Purdue Farms) |
Manure is typically scraped from outside lots every week or two and stacked
until it can be hauled to cropland. It is important to keep an outside
lot relatively free of manure to control odor and so that rainfall runoff
stays mostly free of manure. This facilitates storage of relatively clean
runoff for irrigation onto cropland. It is even possible to divert runoff
from small operations directly to pasture or to a vegetated filter strip
where it can infiltrate. It must be prevented from entering waterways.
Clean upslope water and roof water should be diverted away from the open
lot to minimize the amount of wastewater that must be handled as a manure.
Back to Top
Liquid Manure
 |
| Grow-finish Pigs on Slotted Floor |
| (Source: Purdue University) |
Most swine manure is handled as a liquid. Manure typically falls through
a slotted floor (with the size of slot depending on the size and age of
animal) into either a gutter or a concrete storage pit. Storage pits provides
from 3-12 months storage of the manure. This pit may either be located directly
under the slotted floor and may be from 4' to 10' deep. In some operations,
the manure falls into a shallow pit or gutter which is periodically pumped,
flushed or drained to a large outside storage. The outside storage may either
be constructed in the earth or a commercial steel or concrete storage purchased
and erected onsite . Storage size is dictated by regulatory agencies in
most states and are usually sized large enough to hold at least six month’s
accumulation in Midwestern states. This avoids the need to apply manure
during the crop growing season and when weather conditions are unsuitable
– such as on frozen ground or when the soil is wet enough that heavy
application vehicles could compact and damage the soil for crop production.
 |
 |
Fabricated Steel
Manure Storage |
 |
|
| Liquid Manure Pit Agitation |
Surface Applied Liquid Manure |
| (Source: Purdue University)
|
(Source: Purdue University)
|
Liquid manure from storages is normally agitated thoroughly to make the
manure nutrient content between loads more uniform and hauled to the field
for application in large tanker wagons or trucks. Liquid manure is either
applied to the soil surface or is incorporated during or shortly after
application to control loss of volatile ammonia and release of odors.
Incorporation is very effective at controlling runoff of manure nutrients
and reducing odor from land application if done during or within a few
hours after application. One method is a soil injector, where liquid
manure is “injected” directly into the soil to a depth of
6 to 9” as the tanker passes over the field. This immediate
contact between the manure and soil is highly effective at controlling
odor.
 |
| Injecting Liquid Manure |
| (Source: Purdue University)
|
In remote areas, liquid manure may be pumped to the land application site
and then irrigated onto cropland. Spray irrigating liquid manure is
a very efficient method of land application, in terms of speed and labor,
but odor emissions can be significant; therefore, it is not feasible to
use this method in populated areas.
Back to Top
Lagoons
|
| Two-stage Lagoon System |
| (Source: Purdue University) |
Lagoons are different from liquid manure storages because they are operated
to encourage anaerobic digestion of organic material while it is being stored.
This reduces odor when the treated manure is land applied. A properly designed
and operated treatment lagoon is much larger and more expensive than a liquid
manure storage with the same storage time, and the organic solids are much
less concentrated in the liquid.
 |
 |
| Gravity Drain, Flat Bottom Gutter |
Reverse Hairpin Flat-bottom Gutter |
| (Source: Purdue University) |
(Source: Purdue University)
|
 |
Recirculating Lagoon Water to Flush
Manure from a Gutter under a Slotted Floor |
| (Source: Purdue University) |
In the Midwest, an equal part of relatively clean dilution water must
be added for each part manure. Furthermore, manure must be added
slowly and uniformly to the lagoon, to avoid an upset (and subsequent
release of odors) to the biological treatment system. One common
method of doing this is to utilize shallow pits or gutters under slotted
floors and drain or flush manure to the lagoon on a frequent basis,
usually every three days to three weeks. This is done by simply pulling
a plug in the bottom of the pit, called gravity drain, use of a scraper
system running in the underfloor gutter, through a process called a "hairpen"
gutter or by recirculating a volume of relatively clean effluent from
the lagoon to flush manure out of the building and into the lagoon. Recirculation
involves either a flushing action that takes place several times a day
or a "pit recharge" system that works basically like a toilet that is
flushed every few days.
 |
| Single Cell Waste Treatment Lagoon |
| (Source: Purdue University) |
A portion of the lagoon contents or "minimum design volume" must be left
in the lagoon after its contents are pumped to the land to provide a large
number of microbial organisms to treat the new manure entering the system.
In spite of proper operation, there is an “over turning” of
the lagoon contents that occurs in the fall of the year for a couple of
weeks, as ambient temperature drops and cools the top layer of liquid
in the lagoon. As its density increases, it “overturns”
or drops to the bottom of the lagoon, forcing the bottom layer, containing
partially digested manure solids, to the top. This phenomenon results
in higher odor levels for a week or two around the lagoon. Multiple Lagoons
in series normally emit fewer odors than single cell lagoons.
 |
Irrigation of Lagoon
Effluent onto Cropland |
| (Source: Purdue University) |
Lagoon contents are normally applied to cropland by spray irrigation systems.
If the lagoon is properly designed and operated, spray irrigation should
not release much odor because most of the organic solids should have been
biologically degraded. In a well-operated lagoon, typical effluent
should have only about 20% as much nitrogen (N) and about 30% to 40% as
much phosphorous (P) and potassium (K) as the raw manure, because of treatment
and sedimentation of solids to the bottom of the lagoon. Note that
the P and K "lost" actually accumulate in the sludge and must
be utilized properly when removed. These solids, or sludge, must be removed
every few years and the operation should plan to handle them as a part of
their nutrient management plan. Because this material is more concentrated,
it may be practical to haul the sludge off site to more distant cropland
that can better utilize the nutrients contained in the sludge. Because
of the nuisance potential of this partially stabilized material, it should
be incorporated as a liquid manure if possible.
Back to Top
Back to Pork Main Menu
|
