An ASAE Meeting Presentation
Paper Number: SD05-801
Hydrogen Sulfide Reduction of Swine Manure using
Potassium Permanganate and Hydrogen Peroxide
Sara Smith, Graduate Research Assistant
South Dakota State University, PO Box 2120, Brookings, SD 57007,
sara.smith@sdstate.edu.
Dr. Dick Nicolai, Associate Professor
South Dakota State University, PO Box 2120, Brookings, SD 57007,
dick.nicolai@sdstate.edu.
Written for presentation at the
2005 ASAE Midwest Regional Meeting
Sponsored by ASAE
South Dakota State University
Brookings, SD
Sept 2005- Oct 2005
Abstract. When swine manure is agitated, high levels of hydrogen sulfide (H2S) are released into the
air, which has the potential to cause fatalities. Hydrogen peroxide (H2O2) and potassium
permanganate (KMnO4) have been proven to reduce hydrogen sulfide production in swine manure at
a laboratory scale. The objective of this study was to determine the amounts of H2O2 and KMnO4
that reduce the amount of H2S released at a life-size scale. Two trials of H2O2 and two trials of
KMnO4 were performed. In each trial, H2S was reduced by at least 91%. With the second trial of
H2O2, H2S concentration in the head space was reduced from 50 ppm to 0.38 ppm in 6 minutes.
Additional research is needed to prove the amount of chemicals to add to ensure safe entry of the
pit.
Keywords. Manure, hydrogen sulfide, confined space, safety.
The authors are solely responsible for the content of this technical presentation. The technical presentation does not necessarily reflect the
official position of the American Society of Agricultural Engineers (ASAE), and its printing and distribution does not constitute an
endorsement of views which may be expressed. Technical presentations are not subject to the formal peer review process by ASAE
editorial committees; therefore, they are not to be presented as refereed publications. Citation of this work should state that it is from an
ASAE meeting paper. EXAMPLE: Author's Last Name, Initials. 2005. Title of Presentation. ASAE Paper No. 05xxxx. St. Joseph, Mich.:
ASAE. For information about securing permission to reprint or reproduce a technical presentation, please contact ASAE at hq@asae.org or
269-429-0300 (2950 Niles Road, St. Joseph, MI 49085-9659 USA).
Introduction
As manure decomposes anaerobically, its organic sulfur portion decreases as the
proteins and amino acids containing sulfur breakdown. Sulfur is contained in numerous
compounds at various stages of reduction and oxidation. In the process of degrading
these organic compounds containing sulfur, new compounds are formed that can
volatilize and create odor. The primary route of H2S formation is the mineralization
transformation of organic compounds containing sulfur. The amino acid methionine
hydrolizes into methyl mercaptan and then to methyl alcohol, generating hydrogen
sulfide (ASCE, 1989):
CH3SCH2CHNH2COOH + H2O → CH3SH + NH3 + CH3CH2COCOOH
methionine
methyl mercaptan
CH3SH + H2O → CH3OH + H2S
methyl mercaptan
(1)
ketobutyrate
(2)
methyl alcohol
Spoelstra (1980) indicated that H2S and methyl mercaptan (MM) are the most frequently
reported sulfur compounds in swine manure. The primary origin of H2S in manure is the
reduction of sulfate, which is the primary form of sulfur excreted in urine. The reduction
of sulfate to sulfide was characterized by Sawyer and McCarty (1978):
SO4= + organic matter → S= + H2O + CO2
(3)
The recommended maximum of H2S in air for human health is 5 parts per million (ppm)
and 10 ppm causes eye irritation (Doss, 2002). At 600 ppm, H2S causes
unconsciousness, respiratory failure, and death within minutes (Doss, 2002 and Millar,
1990). In addition, H2S may be explosive at a wide range of concentrations in air--4.3%
to 46% by volume (Millar, 1990).
In many swine and dairy barns manure is scraped into a small collection pit and then
pumped to an outside storage. The equipment in these collection pits requires periodic
maintenance and occasionally is done in the pit. The H2S concentration in the pit head
space may exceed safe human limits.
Also, part of the problem in a swine barn is that the sulfide is created in the air and it
stays within the confined space of the barn. OSHA does have a confined space
standard that industries must follow; however, the standard does not currently apply to
agriculture (OSHA, 2005). In 1990, the National Institute for Occupational Safety and
Health (NIOSH) published a paper stating a “need existed to inform farm owners and
workers about the dangers of entering [swine manure] pits, where oxygen-deficient, toxic
and/or explosive atmospheres often result from fermentation of the wastes in confined
areas,” (Millar, 1990). There was an effort to widely distribute this document for the
prevention of asphyxiation fatalities. Doss et al (1993) suggested that if one must enter
a manure pit, a self-contained breathing apparatus (SCBA) and a safety harness must
be worn with two people available to help remove the body from the pit.
The SCBA equipment cost ranges from $1290.00 to $4264.00 (Fisher Scientific, 2005).
There is also an emergency air unit that costs only $435.00, but the air only lasts for 10
minutes (AFCINTL, 2005). Even with warning publications and availability of SCBA’s,
there continues to be a number of deaths due to entering manure collection pits.
Previous Research
Research performed at the University of Minnesota in 1999 shows the percent reduction
of hydrogen sulfide with the addition of hydrogen peroxide and also with potassium
permanganate. This research was performed in a laboratory in small dishes. The
objective of this research was to evaluate the effectiveness of chemical additions in
reducing H2S gas emissions from waste in a bench-top study. The goal was to identify a
specific chemical and dosage rate. Seven chemicals were tested: Calcium hydroxide,
Ferric chloride, Ferrous chloride, Ferrous sulfate, Hydrogen peroxide, Potassium
permanganate, and Sodium chlorite.
Hydrogen Sulfide Percent Reduction
120.0%
100.0%
80.0%
60.0%
40.0%
20.0%
0.0%
0.000 0.020 0.040 0.060
0.080 0.100 0.120 0.140
Hydrogen Peroxide g/g dry manure
Figure 1. Percent reduction of hydrogen sulfide with the additions of H2O2
(Clanton,1999).
The authors are solely responsible for the content of this technical presentation. The technical presentation does not
necessarily reflect the official position of the American Society of Agricultural Engineers (ASAE), and its printing and
distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not
subject to the formal peer review process by ASAE editorial committees; therefore, they are not to be presented as
refereed publications. Citation of this work should state that it is from an ASAE meeting paper. EXAMPLE: Author's Last
Name, Initials. 2005. Title of Presentation. ASAE Paper No. 05xxxx. St. Joseph, Mich.: ASAE. For information about
securing permission to reprint or reproduce a technical presentation, please contact ASAE at hq@asae.org or 269-4290300 (2950 Niles Road, St. Joseph, MI 49085-9659 USA).
Hydrogen Sulfide Percent Reduction
120.0%
100.0%
80.0%
60.0%
40.0%
20.0%
0.0%
0.000
0.020
0.040
0.060
0.080
0.100
Potassium Permanganate g/g dry manure
Figure 2. Percent reduction of hydrogen sulfide with the additions of KMnO4
(Clanton, 1999).
Hydrogen peroxide and potassium permanganate appeared to be the most cost effective
(Clanton, 1999). The results of Clanton’s (1999) research are shown here in Figures 1
and 2. These data were used to determine the amount of chemical to add to the pit to
potentially reduce hydrogen sulfide. As shown in Figure 1, H2O2 gives an 80% reduction
at 0.05 g/g dry manure.
Potassium Permanganate
KmnO4 reacts with H2S as shown in Equations 4 and 5.
3H2S + 2KMnO4 → 3S + 2H2O + 2KOH + 2MnO2 (Acidic pH)
(4)
3H2S + 8KMnO4 → 3K2SO4 + 2H2O + 2KOH + 8MnO2 (Basic pH)
(5)
KMnO4 is available in dry crystal, granule, or pellet form and must be mixed with water to
approximately a 6% solution (1.04 kg/L).
Hydrogen Peroxide
H2O2 oxidizes H2S into elemental sulfur or sulfate depending upon the pH of the manure,
as shown in Equations 6 and 7.
The authors are solely responsible for the content of this technical presentation. The technical presentation does not
necessarily reflect the official position of the American Society of Agricultural Engineers (ASAE), and its printing and
distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not
subject to the formal peer review process by ASAE editorial committees; therefore, they are not to be presented as
refereed publications. Citation of this work should state that it is from an ASAE meeting paper. EXAMPLE: Author's Last
Name, Initials. 2005. Title of Presentation. ASAE Paper No. 05xxxx. St. Joseph, Mich.: ASAE. For information about
securing permission to reprint or reproduce a technical presentation, please contact ASAE at hq@asae.org or 269-4290300 (2950 Niles Road, St. Joseph, MI 49085-9659 USA).
H2S + H2O2 → S + 2H2O (pH < 8.5)
(6)
H2S + 4H2O2 → SO4= + 2H2O (pH > 8.5)
(7)
These reactions of H2O2 with sulfide are rapid. One to three parts H2O2 are usually
needed per one part sulfide. One of the advantages of H2O2 is that the byproducts are
harmless.
Objective
The objective of this research will compare H2O2 and KMnO4 as sulfur precipitators in
reducing H2S formation from swine manure on a farm-size scale manure collection pit.
Materials and Methods
The experiments were conducted at the South Dakota State University Swine Unit.
Manure from a pull plug system in a gestation barn was emptied into the lift station
collection pit. The lift station is 3 meters by 3 meters by 2 meters in height and sits just
southwest of the swine unit, as shown in Figure 3. The lift station contains a pump and a
valve going out to the storage tank and a valve returning from the storage tank. To
agitate the manure, the pump was run and both valves were open so that no manure
was leaving or entering the lift station pit. After agitating the manure for 10 minutes,
three profile samples were taken using the PVC pipe sampler and mixed in a 5 gallon
pail. This swine manure was then stirred vigorously and poured into a 500mL bottle.
The total solids content was determined following the procedure outlined in
Recommended Methods of Manure Analysis (Peters et al., 2003). The swine manure
was shook in the bottle with the lid tight and 50 mL were measured out. Three dry
crucibles were weighed and 50 mL of swine manure were poured into each of the
crucibles. The crucibles containing the wet manure were weighed again and then
placed in the drying oven under the fume hood. The manure samples were dried at
70oCelcius for 24 hours.
Dry manure content = (Wet manure (gr) – Dry manure (gr))/Wet manure (mL)
(8)
The dry manure content from this first manure sample was found using Equation 8 and
then used to determine the amount of chemical to add for each of the trials. The actual
dry manure content was found for the manure used in each chemical addition in Table 1.
The authors are solely responsible for the content of this technical presentation. The technical presentation does not
necessarily reflect the official position of the American Society of Agricultural Engineers (ASAE), and its printing and
distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not
subject to the formal peer review process by ASAE editorial committees; therefore, they are not to be presented as
refereed publications. Citation of this work should state that it is from an ASAE meeting paper. EXAMPLE: Author's Last
Name, Initials. 2005. Title of Presentation. ASAE Paper No. 05xxxx. St. Joseph, Mich.: ASAE. For information about
securing permission to reprint or reproduce a technical presentation, please contact ASAE at hq@asae.org or 269-4290300 (2950 Niles Road, St. Joseph, MI 49085-9659 USA).
Therefore, the actual amount of chemical added per dry manure content is different than
the predicted amount from the preliminary sample.
Jerome Meter
Sampling Tube
Float for Supporting
Sampling Tube
8 cm
Valve
2m
Manure Pump
To Manure
Storage
3m
Not to Scale
Figure 3. Lift station showing Jerome® meter sampling location used to measure
hydrogen sulfide.
H2S was measured with a Jerome® meter just above the agitated manure before the
chemical was added. As shown in Figure 3, there was a hose mounted on a float, so that
the end of the hose was always 8 cm above the swine manure. The other end of the
hose went into the Jerome® meter to measure H2S. The chemical addition occurred
during a 2-3 minute time period, due to multiple bottles and pouring procedures. Then
H2S was measured for an hour after the addition on 1-2 minute intervals, the lid was
closed, and then opened 2 hours after the addition for more measurements. The H2S
measurements were graphed and analyzed.
Figure 4. The
Jerome meter
was
used to
measure
hydrogen
sulfide.
Figure 5. This float was used to keep
the hose 8 cm above the manure
surface.
The authors are solely responsible for the content of this technical presentation. The technical presentation does not
necessarily reflect the official position of the American Society of Agricultural Engineers (ASAE), and its printing and
distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not
subject to the formal peer review process by ASAE editorial committees; therefore, they are not to be presented as
refereed publications. Citation of this work should state that it is from an ASAE meeting paper. EXAMPLE: Author's Last
Name, Initials. 2005. Title of Presentation. ASAE Paper No. 05xxxx. St. Joseph, Mich.: ASAE. For information about
securing permission to reprint or reproduce a technical presentation, please contact ASAE at hq@asae.org or 269-4290300 (2950 Niles Road, St. Joseph, MI 49085-9659 USA).
Results
From Table 1 column 2, there was less dry manure content in both trials of the KMnO4
than for the trials of H2O2. In column 4, the KMnO4 amounts ended up being much
higher at 0.05613 g/g and 0.0617 g/g than the predicted of 0.03 g/g and 0.04 g/g. More
KMnO4 was added per gram of dry manure than predicted. The KMnO4 additions also
gave the lowest values of H2S, as shown in Figures 6 and 7.
Table 1. Percent dry manure for the preliminary sample and amount of predicted
and actual chemical for each of the four trials.
Percent Dry Matter
Preliminary manure
sample
5 kg KMnO4 Addition
7 kg KMnO4 Addition
7.5 L H2O2 Addition
12.5 L H2O2 Addition
1.14%
0.79%
0.95%
1.33%
1.02%
Predicted Chemical
Amount g/g dry manure
Actual Chemical
Amount g/g dry
manure
0.03
0.04
0.04
0.07
The H2S readings from the first trial of KMnO4 added to swine manure is displayed in
Figure 6. The temperature ranged from 42oF to 45oF during this trial. The H2S readings
were very low and then jumped up abruptly while agitating and adding the chemical.
After 6 minutes, the H2S level was lower and stayed low for 10 minutes, until making a
small jump to 5.9 ppm, then decreasing again for 25 minutes. Then there is a linear rise
over the next two hours up to 8.9 ppm.
The authors are solely responsible for the content of this technical presentation. The technical presentation does not
necessarily reflect the official position of the American Society of Agricultural Engineers (ASAE), and its printing and
distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not
subject to the formal peer review process by ASAE editorial committees; therefore, they are not to be presented as
refereed publications. Citation of this work should state that it is from an ASAE meeting paper. EXAMPLE: Author's Last
Name, Initials. 2005. Title of Presentation. ASAE Paper No. 05xxxx. St. Joseph, Mich.: ASAE. For information about
securing permission to reprint or reproduce a technical presentation, please contact ASAE at hq@asae.org or 269-4290300 (2950 Niles Road, St. Joseph, MI 49085-9659 USA).
0.0513
0.0617
0.045
0.102
Hydrogen Sulfide (ppm)
5 kg KMnO4
18
16
14
12
10
8
6
4
2
0
0:00:00
0:28:48
0:57:36
1:26:24
1:55:12
2:24:00
2:52:48
3:21:36
Tim e
Figure 6. Hydrogen sulfide levels after the addition of 0.0513 gram of KMnO4
per gram of dry manure.
For the 7 kg addition of potassium permanganate, the data are shown in Figure 7. The
initial sampling of H2S was very scattered, and did not even reach 20 ppm. It seemed as
if the pump was not completely agitating the manure, and stirring the manure with a stick
caused the H2S to jump. However, once the chemical was added, the H2S levels were
much lower than for any other trial, the lowest was 0.011 ppm or 11 ppb.
Hydrogen Sulfide (ppm)
7 kg KMnO4
5
4
3
2
1
0
0:00:00
0:28:48
0:57:36
1:26:24
1:55:12
2:24:00
Time
Figure 7. Hydrogen sulfide levels after the addition of 0.0617 gram KMnO4 per
gram of dry manure.
The authors are solely responsible for the content of this technical presentation. The technical presentation does not
necessarily reflect the official position of the American Society of Agricultural Engineers (ASAE), and its printing and
distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not
subject to the formal peer review process by ASAE editorial committees; therefore, they are not to be presented as
refereed publications. Citation of this work should state that it is from an ASAE meeting paper. EXAMPLE: Author's Last
Name, Initials. 2005. Title of Presentation. ASAE Paper No. 05xxxx. St. Joseph, Mich.: ASAE. For information about
securing permission to reprint or reproduce a technical presentation, please contact ASAE at hq@asae.org or 269-4290300 (2950 Niles Road, St. Joseph, MI 49085-9659 USA).
The addition of H2O2 created large bubbles on the surface that turned into a foamy
substance. The temperature during this first trial of H2O2 ranged from 48oF to 52oF. As
shown in Table 1, there was more dry manure content in the swine manure for the H2O2
trials. This may explain the high levels of H2S upon agitation. The H2S level dropped
quickly after the addition of H2O2, down to 2.6 ppm in 3 minutes and to 0.40 ppm within 6
minutes. When the H2S level was checked after two hours, the manure level had
dropped. There may have been untreated manure entering and leaving the pit during
those two hours. This is a possible explanation of the high H2S levels. However, they
could also be due to the 0.045 mL/g dry manure ratio. More research is needed.
Hydrogen Sulfide (ppm)
7.5 L H2O2
60
50
40
30
20
10
0
0:14:24 0:43:12 1:12:00 1:40:48 2:09:36 2:38:24 3:07:12
Time
Figure 8. Hydrgen sulfide levels after the addition of 0.045 mL of H2O2 per gram
of dry manure.
For the second addition of H2S, the level stayed steady. The temperature ranged from
49oF to 52oF. Figure 9 shows that the H2S level dropped off with the addition of H2O2,
from 39 ppm to 0.38 ppm, and then slowly rose over time, up to 19 ppm two hours later.
The authors are solely responsible for the content of this technical presentation. The technical presentation does not
necessarily reflect the official position of the American Society of Agricultural Engineers (ASAE), and its printing and
distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not
subject to the formal peer review process by ASAE editorial committees; therefore, they are not to be presented as
refereed publications. Citation of this work should state that it is from an ASAE meeting paper. EXAMPLE: Author's Last
Name, Initials. 2005. Title of Presentation. ASAE Paper No. 05xxxx. St. Joseph, Mich.: ASAE. For information about
securing permission to reprint or reproduce a technical presentation, please contact ASAE at hq@asae.org or 269-4290300 (2950 Niles Road, St. Joseph, MI 49085-9659 USA).
Hydrogen Sulfide
(ppm)
12.5 L H2O2
45
40
35
30
25
20
15
10
5
0
0:00:00
0:28:48
0:57:36
1:26:24
1:55:12
2:24:00
2:52:48
3:21:36
Time
Figure 9. Hydrogen sulfide levels after the addition of 0.102 mL of H2O2 per
gram of dry manure.
All Trials
30
Hydrogen Sulfide
(ppm)
25
20
15
10
5
0
0:00:00
1:12:00
2:24:00
3:36:00
Time
5 kg KMnO4
7 kg KMnO4
7.5 L H2O2
12.5 L H2O2
Figure 10. Hydrogen sulfide levels over time of two trials of hydrogen peroxide
and two trials of potassium permanganate added to swine manure.
As shown in Figure 10, all trials dropped below 5 ppm initially, and then rose over the
next two hours.
The authors are solely responsible for the content of this technical presentation. The technical presentation does not
necessarily reflect the official position of the American Society of Agricultural Engineers (ASAE), and its printing and
distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not
subject to the formal peer review process by ASAE editorial committees; therefore, they are not to be presented as
refereed publications. Citation of this work should state that it is from an ASAE meeting paper. EXAMPLE: Author's Last
Name, Initials. 2005. Title of Presentation. ASAE Paper No. 05xxxx. St. Joseph, Mich.: ASAE. For information about
securing permission to reprint or reproduce a technical presentation, please contact ASAE at hq@asae.org or 269-4290300 (2950 Niles Road, St. Joseph, MI 49085-9659 USA).
Cost
H2O2 and KMnO4 can be purchased in a 500 lb drum as a liquid and a 330 lb
drum as a dry granular, respectively. The cost for 35% H2O2 is $.65/lb and for
the granular is $2.15/lb (Hawkins, Inc., 2005). For calculations, an entire swine
barn with dimensions 61m x 12m x 1.5m (200 ft x 40 ft x 5 ft) and for a lift station
pit with dimensions 3m x 3mx 2m (10 ft x 10 ft x 6.5 ft). The costs are shown in
Table 2.
Table 2. Cost of chemical to add to an entire pit or to the lift station pit only
(Hawkins, Inc. Sioux Falls, SD September, 2005).
Chemical
KMnO4
KMnO4
H2O2
H2O2
Actual Chemical Amount
0.0513 g/gdry manure
0.0617 g/gdry manure
0.045 mL/g dry manure
0.102 mL/g dry manure
Entire Pit
$2,104.53
$3,085.70
$3,185.24
$5,365.61
Lift Station
Pit
$31.06
$45.52
$46.95
$79.15
Conclusion
H2O2 and KMnO4 at either concentration used reduced H2S to below the 5 ppm
maximum for human health suggested by the National Ag Safety Database. After the 5
kg of KMnO4 addition, H2S level was reduced 91.2% from 17 ppm to 1.5 ppm within 5
minutes. After 25 minutes, the H2S level dropped to 1.2 ppm for a 93% reduction. For
the 7 kg of KMnO4 , H2S dropped 96.7% from 48 ppm to 0.15 ppm within five minutes
and then dropped 99.76% to 0.011 ppm within 21 minutes.
H2S dropped from 48 ppm to 0.4 ppm, a 99.2% reduction, within 6 minutes after the 7.5
Liters of H2O2. After 24 minutes, however, the level rose to 2.4 ppm, a 95% reduction.
After 12 Liters of H2O2 were added, the H2S was reduced 99.1%, from 39 ppm to 0.38
ppm within 6 minutes. After 20 minutes the H2S rose slightly to 1.4 ppm, a 96.4%
reduction.
These four trials have shown that chemical additions work in swine manure at the lifesize scale. Further research will find the exact amounts of H2O2 or KMnO4 needed. Two
trials are not enough to know what amount of chemical is needed to create a safe pit to
enter.
Acknowledgements
The South Dakota State University Swine Unit was cooperative in using their lift station
pit. Ryan Lefers and Lowell Blankers helped with collecting data.
The authors are solely responsible for the content of this technical presentation. The technical presentation does not
necessarily reflect the official position of the American Society of Agricultural Engineers (ASAE), and its printing and
distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not
subject to the formal peer review process by ASAE editorial committees; therefore, they are not to be presented as
refereed publications. Citation of this work should state that it is from an ASAE meeting paper. EXAMPLE: Author's Last
Name, Initials. 2005. Title of Presentation. ASAE Paper No. 05xxxx. St. Joseph, Mich.: ASAE. For information about
securing permission to reprint or reproduce a technical presentation, please contact ASAE at hq@asae.org or 269-4290300 (2950 Niles Road, St. Joseph, MI 49085-9659 USA).
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Accessed April 14, 2005.
Peters, J., S. M. Combs, B. Hoskins, J. Jarman, J. L. Kovar, M. E. Watson, A. M. Wolf,
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The authors are solely responsible for the content of this technical presentation. The technical presentation does not
necessarily reflect the official position of the American Society of Agricultural Engineers (ASAE), and its printing and
distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not
subject to the formal peer review process by ASAE editorial committees; therefore, they are not to be presented as
refereed publications. Citation of this work should state that it is from an ASAE meeting paper. EXAMPLE: Author's Last
Name, Initials. 2005. Title of Presentation. ASAE Paper No. 05xxxx. St. Joseph, Mich.: ASAE. For information about
securing permission to reprint or reproduce a technical presentation, please contact ASAE at hq@asae.org or 269-4290300 (2950 Niles Road, St. Joseph, MI 49085-9659 USA).