For more: http://www.extension.org/67583 Treatment lagoons are one of the most common biological treatment methods used on swine and dairy farms that use recycled supernatant as a means to remove manure from animal housing facilities by flushing. A properly functioning treatment lagoon will provide adequate treatment to allow reuse of the effluent without compromising animal health or generating strong odor. A lagoon should have a minimum biological treatment volume and provide sufficient volume for settling and storage of sludge to provide the needed levels of treatment prior to recycling. This presentation will provide a summary of the benefits of using liquid-solid separation to maintain and potentially reduce the required treatment volume, reduce sludge build-up, increase useful life of an existing lagoon, and to reduce the size of new lagoons based on the ASABE Standard. Information will also be provided concerning desired loading rates and supernatant concentrations for recycling, and impacts of odor production potential.
Benefits of using liquid-solid separation with manure treatment lagoons
1. Benefits of Using Liquid-Solid
Separation with Manure
Treatment Lagoons
John P. Chastain, Ph.D., Professor and Extension Agricultural
Engineer, School of Agricultural, Forest, and Environmental
Sciences, Clemson University
Jeffery Porter, Environmental Engineer, USDA-NRCS Manure
Management Team
Waste to Worth Conference, Denver, Colorado
Grand Hyatt Hotel • April 1-5, 2013
2. Purpose
Define a manure treatment lagoon and how it
is sized.
Summarize the benefits of using liquid-solid
separation prior to lagoon treatment.
3. Liquid-Solid Separation Options
1. Separation based on particle size – screens &
presses.
2. Separation based on density of the manure –
gravity & cyclones
3. Can provide solid removal efficiencies in the
range of 10% to 60% depending on species
and manure solids content.
6. Combination of an in-channel fighted conveyor screen
and a small screw press to treat liquid swine manure
Screw Press
7. Liquid-solid separator that employs three
techniques: fine stationary incline screen (0.020
in), screw press, and an inclined fighted
conveyor screen (courtesy of US FARM
Systems, Tulare, CA).
9. Since the settled solids are slurry they can be
used to load a press if dry solids are needed.
10. Chemicals can be used to remove 70%
to 90% of the solids and P for most
methods of liquid-solid separation
- Need proper dose
- Need proper mixing
- Need proper dilution
- Need $$$
11. Benefits of Liquid-Solid Separation for
Manure Storages – not for recycle systems
This is not a lagoon.
12. Benefits of Liquid-Solid Separation for
Storages
Remove large particles to reduce energy and
time needed for agitation and pumping
Reduce manure storage volume by up to 20%
if TS removal is on the order of 40%.
Remove large particles that could cause
clogging of pipes and nozzles.
14. Lagoon Sizing
Lagoon Volume = (Manure Volume +
Treatment Volume + Sludge Storage Volume)
On top of these volumes add DEPTHS for
Net Rain (P+R), 25 year – 24 hr storm +
minimum of 12” of freeboard.
These depths are required for any manure
storage.
16. Well treated recycled lagoon water needed
for manure removal.
High loading rates = strong recycle water for
flush and pit-recharge buildings.
Need well treated lagoon water to make recycle
flush and pit-recharge buildings function
properly.
Maximum loading for recycle should be based on
ASABE Standard.
17. Use of a mechanical separator (MS) to reduce
loading on lagoon
18. Enhancing solids and nutrient removal by using
chemicals slows the system down in this configuration.
19. Gravity settling can be used to make high-rate
mechanical separation easier – also reduces chemical
costs.
20. Add a settling basin or pond before the
lagoon – basins drain dry, ponds do not.
21. Can use chemicals to enhance removal of solids and
plant nutrients for a settling basin or pond.
22. Manure Storage Volume
Will include all manure, wasted water, and
other solids added to manure per day
(bedding and wasted feed)
Typically use a storage period ranging from
180 days in warm southern climates to 365
days in cold climates (e.g. Midwest)
Liquid-solid separation can reduce this
volume by 10% to 25%. Best to be
conservative.
23. Treatment Volume
Depends on VS loading rate , LR = lb
VS/1000ft3
/day.
TV (ft3
) = 1000 (lb VS/day / LR)
Design loading rate depends on the climate.
Larger loading rates can be used in warm
climates than in cold climates (ANSI/ASAE
EP403.4, ASABE, 2011)
24. Variation of LR With Climate
(ANSI/ASAE EP403.4, ASABE, 2011)
Location
Loading Rate, lb
VS/1000ft3
/day
Southern Minnesota (Cold) 3.0
Iowa 3.5
Kansas 4.0
North Carolina 4.5
South Carolina & Georgia 5.0
Central Texas 5.5
Central Florida (Hot) 6.0
28. Liquid-solid separation will reduce sludge build
up in a treatment lagoon – Critical for dairy!
TS Removed By
Separator
Swine
Sludge Volume
Per Year
Dairy
Sludge Volume
Per Year
0% 52.0 ft3/AU 383.2 ft3/AU
20% 41.6 306.5
40% 31.2 229.9
60% 20.8 153.3
80% 10.4 76.63
Solids Production: Swine = 6.5 lb TS/AU/day, Dairy = 14.4lb/AU/day
29. Odor Reduction?
Research has shown that most of the odor
comes from particles that are smaller than
0.0098” (0.25mm).
Must have high-rate separation to greatly
reduce odor production from liquid manure.
However lower VS loading rates have been
shown to reduce frequency of odor from a
lagoon.
30. Effect of VS Loading Rate on Odor
Frequency (adapted from Humenik, et al. 1981)
31. Summary
Liquid-solid separation can be used to
significantly reduce treatment and sludge
storage volumes.
Allows use of smaller structures to save
money.
Allows more economical use of lower loading
rates to improve recycle water quality.
Can help reduce ammonia and odor
production
32. Summary (2)
Can allow use of anaerobic treatment lagoons
in colder climates.
Can be used to remove a portion of VS and
Organic-N that would breakdown in the
lagoon to yield methane, ammonia, and
carbon dioxide.
Reduces cost of sludge management to
maintain lagoon function.