Transcript Silage Leachate - Webinar Portal

Bill Reck
Peter
Vanderstappen
Environmental Engineer
USDA NRCS
East National Technology
Support Center
Assistant State Engineer
USDA NRCS
Pennsylvania
 Have you worked on planning a silage leachate
treatment system?
Bill Reck
Environmental Engineer
USDA NRCS
East National Technology
Support Center
ftp://ftp-fc.sc.egov.usda.gov/NWMC/EQTN5Lon.pdf
 Organic juice
 Contaminated runoff from spilled or stored silage.
BOD5
Raw domestic sewage 300 to 400 mg/l
Silage Leachate 12,000 to 90,000 mg/l
Nitrate
25% of N in silage leachate is Nitrate
 One gallon of silage effluent can cause the
oxygen content of 10,000 gallons of fresh water
to be lowered below the level required for fish
survival. Fish kill.
 300 tons of high-moisture silage creates an
effluent with a comparable oxygen demand to
the sewage generated daily by a city of 80,000
people
 Time of year is problematic.
 Silage leachate is usually produced in late summer
and early fall when streams are at greatest risk to
impact from BOD load. Streams are already low in
total oxygen because of seasonally high temperatures
and seasonally low flow which means that high BOD5
liquid will likely have the greatest impact.
 In addition, the acidic nature of silage leachate
can burn or kill vegetation in the area where it
drains.
 Odor
 90% water
 pH 5.5 to 3.6
 0.09-0.27 lbs/cf Nitrogen
 0.02-0.04 lbs/cf Phosphorus
 0.21-0.32 lbs/cf Potassium
 Provide storage or treatment of all processgenerated wastes and polluted runoff from the
confinement area for a 25-year, 24-hour storm
event
 Process generated includes feed storage areas
 Planned & organized into 6 inter-related
functions:
7.5 gallons per ton (AWMFH)
% dry matter
<15
15 to 20
20 to 25
>25
Gal/ton
50 to 100
30 to 50
5 to 30
0 to 5
1 cf / ton / day for 3 to 5 days
0.5 cf / ton / day at 18% moisture
 50% of leachate first week.
 25% the next two weeks
 Continues for up to eight weeks after ensiling
Mason 1988
 Secondary Leachate
 rainfall, groundwater or stormwater can generate
more leachate for the life of the silage stack
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Cut Silage at Low Moisture Content
Cut Silage in Dry Weather
Make larger cuts
Keep cutting blades sharp
Eliminate ground and surface water
infiltration
Cover before rainfall events & positive
drainage
Keep bunker silo faces vertical
Keep loading area clean
Use absorbent materials
 Keep leachate stream separate from runoff
stream
 Diversions
 Intercept Groundwater
 Roof Gutters
 Consider Corrosion
 Low Flow – High Flow Separation
 Collect/store only the low-flow concentrated wastes
 Divert the rainfall runoff low-concentrated wastes to a
designed grass filter area.
 Solids Separation
 Store with contaminated runoff storage
 Store with Manure (CAUTION H2S)
 If undiluted, consider acidic corrosion
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Dilution – 1:1 with water
Storage time
Aeration
Neutralization
 Gravity or pump?
 If undiluted, Resist
Corrosion
 If diluted, conventional
equipment
 Pre-charge with water
to dilute
Sump Pump
 Land application
 Animal Feed (not recommended)