EPA 660/2-74-023
April 1974
Environmental Protection Technology Series
Odors From Confined
Livestock Production
Office of Research and Development
U.S. Environmental Protection Agency
Washington, D.C. 20460
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and
Monitoring, Environmental Protection Agency, have
been grouped into five series. These five bread
categories were established to facilitate further
development and application of environmental
technology. Elimination of traditional grouping
was consciously planned to foster technology
transfer and a maximum interface in related
fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL
PROTECTION TECHNOLOGY series. This series
describes research performed to develop and
demonstrate instrumentation, eguipment and
methodology to repair or prevent environmental
degradation from point and .non-point sources of
pollution. This work provides the new or improved
technology required for the control and treatment
of pollution sources to meet environmental quality
standards.
EPA REVIEW NOTICE
This report has been reviewed by the Office of Research and
Development, EPA, and approved for publication. Approval does
not signify that the contents necessarily reflect the vievs and
policies of the Environmental Protection Agency, nor does
mention of trade names or commercial products constitute
endorsement or recommendation for use.
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EPA-660/2-74-023
April 1974
ODORS FROM CONFINED LIVESTOCK PRODUCTION
A State-of-the-Art
J. Ronald Miner
Agricultural Engineering Department
Oregon State University
Corvallis, Oregon 97331
Project Officer
R. Douglas Kreis
Robert S. Kerr Environmental Research Laboratory
P. 0. Box 1198
Ada, Oklahoma 74820
Grant No. R802009-01
Program Element 1BB039
Prepared for
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D. C. 20460
For aaie by the Superintendent of Document*, U.S. Government Printing Office Washington, B.C. 2W02 - Price $1.70
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ABSTRACT
Current livestock production techniques result in the generation of odors
which have become a source of conflict between livestock producers and
society. The odorous gases responsible for the nuisance are principally
low molecular weight compounds released during anaerobic decomposition of
manure. Manure management systems which control or modify this decomposi-
tion offer the greatest potential for odor control.
Research to identify the chemical compounds present in odorous air from
animal waste degradation has yielded about 45 compounds to date. The
amines, mercaptans, organic acids and heterocyclic nitrogen compounds are
generally regarded as being of greatest importance. Among the techniques
for odor control are: (a) site selection away from populated areas and
where adequate drainage exists, (b) maintain the animal areas as dry as
possible and prevent the animals from becoming manure covered, (c) select
manure handling systems which utilize aerobic environments for manure
storage, (d) maintain an orderly operation free of accumulated manure and
runoff water, (e) practice prompt disposal of dead animals and (f) use
odor control chemicals when short term odor control is necessary, such as
when manure storage tank contents must be field spread.
This report was submitted in partial fulfillment of Project Number S-802009
under the partial support of the Office of Research and Monitoring, Envi-
ronmental Protection Agency.
ii
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CONTENTS
Sections Page
Abstract ii
List of Figures v
List of Tables vi
Acknowledgements ix
Summary 1
I Introduction to Odor Causes and Control 5
II Human Response to Odorants 9
Doctrine of Nuisance 11
III Animal Response to Odorants 15
Ammonia 15
Hydrogen sulfide 16
Mixed air pollutants 17
IV Theory of Odor Perception 19
Mechanisms of perception 22
Odor strength 25
Odor quality 28
Limitations of odor testing 29
Supplementary instruments 34
V Relationship between Odor and pH 37
VI Desorption of Ammonia 39
From liquid poultry manure 41
From cattle feedlots 41
From dairy pens 42
From anaerobic lagoons 44
VII Identification of Odorous Compounds 45
Poultry manure 45
Cattle feedlots 49
Swine manure 51
Miscellaneous measurements 54
Summary 54
VIII Measurement of Specific Odorous Gas Concentrations 57
Ammonia 57
Hydrogen sulfide 59
Mercaptans 59
Volatile organic acids 61
IX Quantitative Measurement of Odors 63
Odor strength 63
Scentometer 65
Odor quality 69
iii
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Sections Page
X Fecal Odor as Affected by Feed Additives 71
XI Chemical Treatment of Manure to Control Odors 75
Chlorine and lime 75
Potassium permanganate 76
Hydrogen peroxide 77
Dairy manure 77
Swine manure 79
Poultry manure 79
Paraformaldehyde 80
XII Use of Soil Filters to Remove Odorants 85
XIII Use of Proprietary Odor Control Chemicals 89
XIV Waste Management Techniques to Minimize Odors 93
Open lots 93
Confinement buildings 95
Animal-manure separation 96
Manure storage 96
Anaerobic lagoons 98
XV References 101
XVI Appendices 109
iv
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FIGURES
Number
1 Anaerobic Breakdown of Proteins 6
2 Bacterial Transamination 6
3 Pathways of Carbohydrate Breakdown 6
4 Human Nasal Cavity 21
5 Olfactory Mucosa 21
6 Schematic Diagram of Scentoraeter 67
v
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TABLES
Number Page
1 Use of Restrictive Environments to Control the 7
Formation of Manure Odors by Anaerobic Decom-
position
2 Characteristics of Farm Animal Manures 8
3 Manure Production and Characteristics of Live- 8
stock in Confinement, Per 1,000 Pounds Live
Weight
4 Characteristics and Perceptible Concentrations 9
of Various Substances in Air
5 Threshold Limit Values for Various Gases Asso- 11
ciated with Animal Waste Odors
6 The Human Senses, Examples of Parameters Mea- 22
sured and Alternate Information Sources
7 Basic Odor Ovuality Classifications as Described 28
by Five Authors
8 pH Values for which Various Odorous Compounds 37
are 50 percent Ionized at 25° C
9 Fraction of Total Ammonia Concentration Pre- 40
sent as NH_ as a Function of Temperature and
pH
10 Mean Ammonia Nitrogen Adsorption Rates by Di- 42
lute Acid Traps from 27 July 1968 through 27
February 1969 in Northeastern Colorado
11 Atmospheric Concentration of Distillable Ni- 43
trogen (Ammonia plus Amine) near Chino, Cal.
12 Average Weekly Adsorption of Distillable 43
(Ammonia plus Amine) Nitrogen by Acid Sur-
face Traps near Chino, Cal., January 11 to
February 15, 1972.
13 Ammonia Production by White Leghorn Layer Manure 48
Added Daily to a 19 Liter (Five Gallon) Carboy
14 Hydrogen Sulfide Production by White Leghorn Layer 48
Manure Added Daily to a 19 Liter (Five Gallon)
Carboy
vi
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Number Page
15 Odorous Gas Detection and Identification Schemes 50
Evaluated by Fosnaugh and Stephens
16 Odorous Compounds Identified from the Atmosphere 51
in a Beef Cattle Confinement Chamber under Three
Manure-Handling Programs
17 Gas Concentrations Measured in an Enclosed Swine 53
Unit when Ventilated and when Ventilation had
been Interrupted for Six Hours
18 Compounds Identified in the Air from the Anaero- 56
bic Decomposition of Livestock and Poultry Manure
19 Calculated pH Values of Distilled Water in Equi- 58
librium with Various Ammonia Concentrations in
Air at 20° C
20 Ammonia Concentration (ppm) in Air Based on the 58
pH of a Test Paper after 15 Seconds of Contact
21 Odor Intensity Index and Odorous Components in 66
the Supernatant of Liquid Dairy Manure Receiv-
ing Various Rates of Aeration
22 Dilution to Threshold Values with Various Ports 68
Open on a Scentometer when an Odor is Barely De-
tectable
23 Composition of Basal Diet for Animals on Fecal 71
Odor Study
24 Treatments and Results - Trial 1. Texas Tech 72
University Swine Fecal Odor Study
25 Treatments and Results - Trial 2. Texas Tech 72
University Swine Fecal Odor Study
26 Treatments and Results - Trial 3. Texas Tech 73
University Swine Fecal Odor Study
27 Chromatographic Results After 2 Weeks - Trial 73
3. Texas Tech university Swine Fecal Odor Study
28 Chromatographic Results After 3 Weeks - Trial 74
3. Texas Tech University Swine Fecal Odor Study
29 Percent Weight Loss of Flake Paraformaldehyde 80
when Exposed to Ammonia-Free Air at Various
Temperatures
vii
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Number Page
30 Percent Weight Loss of Flake Paraformaldehyde 81
in Presence of Ammonia Gas from Chicken Manure
at 22° C
31 Ammonia Content (ppm) of Headspace Gas Over 100 82
Grains of Chicken Manure Treated with Various
Levels of Paraformaldehyde
32 Bacterial Counts of Manure Samples on Brain 82
Heart Infusion Agar After 11 Days of Exposure
to Various Quantities of Paraformaldehyde
33 Manufacturers of Odor Control Products for Use 92
in Controlling Manure Odors
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ACKNOWLEDGEMENT
The preparation of this report was supported in part by Grant No. S-802009,
U.S. Environmental Protection Agency. The cooperation of R. Douglas Kreis,
Project Officer, Office of Research and Monitoring, Ada, Oklahoma, is grate-
fully acknowledged.
The technical and editorial assistance of Ted L. Willrich, Extension Agri-
cultural Engineer, and Richard Floyd, Agricultural Experiment Station Edi-
tor, Oregon State University, was instrumental in the completion of this
report. The material in Section IV on the theories of odor perception was
taken, to a large measure, from a literature review paper presented by
Clyde L. Earth, Clemson University, during the July, 1970, meeting of the
American Society of Agricultural Engineers.
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SUMMARY
The phenomenon of olfaction is complex. Several models have been proposed
to explain the observations relative to odor perception and identification,
yet none of the models are entirely satisfactory. Psychological aspects
of odor evaluation compound the difficulties in making objective measure-
ments of either odor strength or odor quality. Correlations between the
chemical composition of air and its odor have proven more difficult than
anticipated.
Anaerobic decomposition of manure is a stepwise process in which complex
organic compounds are degraded to successively smaller, less complex mole-
cules. Since, at a given moment, any or all of these intermediate com-
pounds may be present, the observed odor represents the sum of the indi-
vidual contributors. Data indicate that the total odor may not represent
the simple summation of individual contributors but that extensive inter-
action is occurring.
Research to identify the chemical compounds present in odorous air from
animal waste degradation has yielded about 45 compounds to date. Even
though this list is undoubtedly incomplete, it indicates the complexity
of the situation and forewarns of the difficulties to be encountered in
odor control. The amines, mercaptans, organic acids, and heterocyclic
nitrogen compounds are generally regarded as being of greatest odor sig-
nificance.
The measurement of odors has proven difficult and current techniques are
not entirely satisfactory. Odor intensities can be measured by determin-
ing the volume of odor-free air required to dilute a volume of odorous
air to a barely perceptible level. Both laboratory and field equipment
are available for this use. In this technique, the human nose is the de-
tector; therefore, considerable variation due to observer sensitivities
and fatigue is common. A liquid dilution technique has been utilized for
evaluating the odor of liquids in which odor-free water is used as the
dilutant.
1
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Chemical techniques exist for measuring the concentration of many odorous
compounds produced by the anaerobic decomposition of manure. The low con-
centration at which these compounds are odorous in air, however, frequent-
ly exceeds the sensitivity of existing analytical techniques. Thus, ex-
tensive modification of traditional analytical techniques is necessary.
Ammonia, hydrogen sulfide, mercaptans, and volatile organic acids have
been quantitatively measured in the air-volatilized material from manure
storage tanks.
Although certain odorous gases are known to be toxic to both humans and
livestock, the primary concern is one of annoyance or nuisance to humans.
Rules and regulations relative to livestock odors are based primarily on
the concept of nuisance. Whenever a neighboring property owner feels the
odor from an animal production unit is unreasonably interfering with the
use and enjoyment of his property, he has the right to initiate legal
action to recover damages or to seek an injunction to halt or modify an
operation. Both private and public nuisance suits have been heard in the
last five years. In some of these cases the judgments have involved major
expenses for the livestock producer and, in a few instances, required that
a producer cease operation or move to a more appropriate location.
Ammonia has been the most widely studied odorous gas being evolved by
anaerobic manure decomposition. The evolution of ammonia is of interest
not only because of its odor but also because the potential for reabsorp-
tion by nearby water bodies would lead to the possibility of aquatic en-
richment. The atmosphere near livestock production units has been mea-
sured in enough locations to demonstrate a significant increase in ammonia
concentrations in these areas compared to residential or other agricultural
areas. The volatilization rate of ammonia is a function of temperature,
pH and ammonia content of the material from which it would escape.
Scattered observations have suggested that the odor of manure can be in-
fluenced by changing the feed ration of an animal. Sufficient data have
been gathered to indicate this is a feasible approach, yet not enough work
has been done for this to be considered a viable odor control technique.
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Various chemical treatments have been explored for reducing the odor of
stored animal manure. Chlorine, lime, potassium permanganate, hydrogen
peroxide and paraformaldehyde have been applied to manure for their char-
acteristics of inhibiting anaerobic bacterial activity and their reaction
with known odorous compounds. These chemicals have been demonstrated to
be temporarily effective when added in sufficient concentration. There
are several proprietary odor control chemicals being sold for odor reduc-
tion or masking. Their performance has received only limited study and
the published results are highly variable.
Soil columns have been studied as a means of removing odorous compounds
from air. Their performance under laboratory conditions has been encour-
aging but they have not been applied to production facilities.
Although complete odor elimination around a livestock operation is not
currently within technical and economic limits, there are several prin-
ciples that have been proposed to minimize odor complaints.
(a) Locate a livestock operation such that close proximity to residential
areas is avoided. Although no maximum distances have been established
beyond which complaints are not valid, it is desirable to stay away
from an urban area, 1600 m (one mile) from housing developments and 800 m
(1/2 mile) from neighboring residences. Wind direction and topography
are of some importance in most areas. However, in some areas there is
sufficient fluctuation in wind direction to make this factor of little
help.
(b) Feeding areas and animal pens should be kept dry. The primary source
of odor from a livestock operation is that of anaerobic manure decompo-
sition. By keeping manure-covered surfaces dry, this decomposition can
be minimized. This same procedure not only is helpful as an odor con-
trol scheme, but also is beneficial in the control of water pollution
due to runoff and is an aid in fly and insect control.
(c) Manure-management systems should be designed to prevent dirty, manure-
covered animals. The warm body of an animal, when covered with wet
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manure, makes an area of accelerated bacterial growth and odor produc-
tion. Once produced, the odorous by-products of manure decomposition
are quickly vaporized into the air by animal heat.
(d) Appropriate selection of manure storage and treatment devices can be
helpful. The use of aerobic systems in general will reduce odor pro-
duction. Other measures to inhibit anaerobic decomposition such as
dry manure storage, chlorine or lime addition, or a cold storage sys-
tem will reduce odorous gas production.
(e) An orderly scheme of runoff collection and manure handling not only
avoids opportunity for water pollution but also promotes better drain-
age, thus minimizing areas of odor production. In addition, an orderly
appearing operation is effective in suggesting a non-offensive situa-
tion.
(f) Dead animal disposal requires a definite plan to avoid odors, flies,
and severe health risks. Prompt handling, with removal from the site
within 24 hours, is required in most areas. Pickup by rendering
works is the preferred disposal method where quickly available; other-
wise, burial or incineration may be considered.
(g) Odor control chemicals have achieved limited use in livestock opera-
tions. Because of the lack of an effective means of evaluating the
performance of these materials and their expense, odor control chemi-
cal use has been generally limited to short-term applications or use
only in particularly offensive areas, such as a manure-storage pit
immediately before hauling.
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SECTION I
INTRODUCTION TO ODOR CAUSES AND CONTROL
Odors associated with livestock production are generally related to
manure handling but other potential odor sources exist. Wet feed, if
not promptly removed, makes a contribution to odors as does the decom-
position of dead animals if they do not receive proper handling. Ani-
mal feeds also have various odors as they are stored and handled before
feeding and as they are fed. However, feed odors are not generally re-
garded as offensive as those from the decomposition of manure.
Manure is a complex mixture of carbohydrates, fats, proteins and their
breakdown products. When manure is in a suitable environmental condition
during handling, it serves as a substrate for biological growth. This
biological growth utilizes the manure as an energy source and yields one
of the next succeeding compounds along the metabolic chain. Examples
of the biological transformations occurring in manure are shown in Figures
1, 2 and 3. When manure undergoing decomposition has a surface exposed
to the atmosphere, volatile products and intermediates will tend to es-
cape into the atmosphere. This is the source of odorous gases and vapors.
One method of avoiding odors is to prevent the formation of odorous break-
down products. Although frequently difficult or even impossible to accom-
plish in practice, the principle is straightforward: Maintain the manure
in an environment unsuitable for the growth of anaerobic microorganisms.
This can be done by: (a) providing an aerobic environment, (b) maintaining
the moisture content so low that growth is inhibited, (c) controling the
pH so that growth is inhibited, (d) adjusting the temperature outside the
region of bacterial growth, (e) adding a chemical which inhibits biologi-
cal growth, or (f) by changing the microbial population so the formation
of specific compounds is avoided.
Although difficult as a means to achieve total odor control, each of the
above restrictions on microbial growth has been investigated. Each has
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Ammonia
NH,,
Proteins
I
Proteoses
;
Peptides
1
Amino Acids
H
[R- C -COOH]
Hydroxy Acid [R- C -COOH]
i
OH
H
Volatile Organic Acid [R- C -COOH|
H
Figure 1. Anaerobic breakdown of proteins
R
i
R
H- C -NH + C =0 »
COOH R EaZyme
Amino Acid Ketone
R R
i I
C =0 + H- C -NH,
i
COOH
Keto
Acid
H
Amine
Figure 2. Bacterial transamination
Polysaccharide
i
Disaccharide
i
Hexose
i
Pyruvic Acid
AEROBIC CONDITIONS
Carbon Dioxide
Water
^ ANAEROBIC CONDITIONS
Acids
Aldehydes
Alcohols
Re tones
Carbon Dioxide
Methane
Figure 3. Pathways of carbohydrate decomposition
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specific limitations either in. terms of technology or cost. However,
most are finding application in the control of manure odors as is indi-
cated in Table 1.
Table 1. USE OF RESTRICTIVE ENVIRONMENTS TO CONTROL THE FORMATION OF
MANURE ODORS BY ANAEROBIC DECOMPOSITION
Technique Application Limitation
Aerobic environment Oxidation ditch Power and equip-
Aerated lagoon ment costs
Moisture control Manure dryers Manure transport
Power ventilated poul- Control of water
try manure pits leaks
pH adjustment Lime application Ammonia release,
cost, solids
increase
Temperature Freezing Cost-handling
Chemical inhibition Chlorination Cost
Microbial population Digestive aids Technology
adjustment
Considerable work has been done to determine the characteristics of animal
manures as produced by the specific animal. Summaries of these character-
istics are included in Tables 2 and 3. Animal waste characteristics have
been determined primarily for use in assessing water pollution effects or
the parameters for liquid waste handling. Little attention has been given
to analysis of these waste products specifically oriented toward odor pro-
duction and control.
The odor of fresh manure can be intuitively assumed to be a function of
the animal specie, the feed ration being consumed, and the existing micro-
floral population within the animal intestine. Within these variables
would be included the absence or presence of intestinal diseases and spe-
cific metabolic disorders of the animal as well as environmental stresses
which might be influential in changing the animal's feed utilization.
These considerations suggest that there may be great variation in the
7
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volatile compounds present within manures from a specific specie. After
being voided by the animal, the manure's further decomposition will be
influenced by the environment in which it is maintained. At this point,
another opportunity for odor control exists. Variables which offer some
potential control are moisture condition, dissolved oxygen level, and
specific biological controls which might be used to alter the course of
decomposition. For any specific metabolic process, other potential means
of varying the odor release pertain to the control of volatilization of
the odorous compounds, the amount of dilution which occurs, and the proxim-
ity of the odor source to the potentially offended persons.
Table 2. CHARACTERISTICS OF FARM ANIMAL MANURES PER THOUSAND LIVE WEIGHT
UNITS PER YEAR (POUNDS OR KILOGRAMS)2
Animal
Dairy
Beef
Poultry
Swine
Sheep
N
131
170
262
147
123
P2°5
36.1
26.3
292
66
43
K
55.8
39.4
134
37
89
BOD5
1.7
1.5
4.0
2.1
0.7
Table 3. DAILY MANURE PRODUCTION AND CHARACTERISTICS OF LIVESTOCK IN CON-
3
FINEMENT, PER THOUSAND LIVE WEIGHT UNITS (POUNDS OR KILOGRAMS)
Raw manure (RM)
Total solids (TS)
Total solids, percent RM
Volatile solids (VS)
Volatile solids, percent TS
BOD
BOD,., percent VS
BOD^, percent COD
Nitrogen, percent TS
Phosphoric acid, percent TS
Potassium, percent TS
Dairy
88
9.0
10.0
7.2
80
1.7
24
16
4.0
1.1
1.7
Beef
60
6.0
10.0
4.8
80
1.5
31
17
7.8
1.2
1.8
Hens
59.0
17.4
30.0
12.9
74
4.4
34
28
5.7
4.6
2.1
Pigs
50
7.2
14.4
5.9
82
2.1
35
33
5.6
2.5
1.4
Sheep
37
8.4
22.7
6.9
82
0.7
10
8
4.0
1.4
2.9
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SECTION II
HUMAN RESPONSE TO ODORANTS
Although certain odorous gases are known to be harmful and toxic, the
principal effect upon humans is one of annoyance or discomfort. The
phenomenon of toxicity, although important in the area of industrial hy-
giene and overall human health, is not generally the problem with respect
to livestock waste odors. Specific human health hazards associated with
gases which evolved from animal waste are limited to situations in which
persons encounter large concentrations of such gases. Particularly haz-
ardous are instances where people enter manure storage tanks without
adequate ventilation or situations in which explosive mixtures of meth-
ane have been captured within a building and then ignited.
Several gases identified in livestock manure odors are of concern in
atmospheres in an industrial setting where people might work. Table 4
lists several gases which may be encountered in an odorous environment
and the concentrations which are considered not to be hazardous to human
health or safety.
Table 4. CHARACTERISTICS AND PERCEPTIBLE CONCENTRATIONS OF VARIOUS SUB-
STANCES IN AIR
Concentration
_, causing faint odor
Odor 6_9
Substance Characteristic 10 g/1
Acetaldehyde Pungent 4
Ammonia Sharp, pungent 37
n-Butyl mercaptan Strong, unpleasant 1.4
Carbon disulfide Aromatic odor, slightly 2.6
pungent
Ethyl mercaptan Odor of decayed cabbage 0.19
Hydrogen sulfide Odor of rotten eggs, 1.1
nauseating
Methyl mercaptan Odor of decayed cabbage 1.1
or onions
Propionaldehyde Acrid, irritating odor 2
Propyl mercaptan Unpleasant odor 0.075
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Ammonia has been one of the gases associated with livestock wastes of
greatest interest to both researchers and livestock producers. It is
produced in relatively large quantities by the anaerobic decomposition
of proteinaceous material and by the breakdown of urea. Ammonia has a
distinctive odor discernible by most observers at concentrations of ap-
4
proximately 0.037 mg/1 or 30 ppm by volume. Other researchers have re-
ported ammonia threshold odors of 46.8 ppm. One complication is that
ammonia is seldom encountered independently of other odorous compounds.
Several other compounds, particularly the amines, have odor qualities
quite similar to ammonia, but are detectable at much lower concentra-
tions. At concentrations of approximately 0.3 - 0.5 mg/1, ammonia acts
as an irritant to the eye, nose and throat of humans. At high concen-
trations it acts as an asphyxiant. Similar reactions have been noted
in domestic animals with the additional observation that at even low
concentration ammonia tends to interfere with the action of the cilia
of the upper respiratory tract.
Hydrogen sulfide has been of concern relative to livestock wastes because
of its toxicity to both humans and animals as well as its objectionable
odor. Concentrations in excess of 400 ppm have been toxic to man. Sim-
ilar levels also are responsible for livestock deaths. Hydrogen sulfide
poisoning of animals has always been associated with some event such as
agitating a manure storage tank which caused the H S level to rise up to
1000 ppm for a short period. Chronic H S poisoning is not a problem be-
cause it is rapidly oxidized to sulfate in the blood.
The most common complaint relative to livestock production is that of
odor. Table 5 lists several gases associated with animal waste odors
and their perceptible, threshold concentrations. An odor may be inter-
mittent, the usual case, or in certain instances may be continuous. Per-
sons living near livestock production facilities are protected under the
law by the concept of nuisance. A nuisance in the legal sense may be
summarized as anything which causes an unreasonable interference with
the use and enjoyment of property. The various aspects of nuisance rel-
Q
ative to livestock production were treated in some detail by Paulson.
10
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Table 5. THRESHOLD LIMIT VALUES* FOR VARIOUS GASES ASSOCIATED WITH ANI-
MAL WASTE ODORS
——— . —
Substance Concentration 10 g/1
Acetaldehyde 360
Acetic acid 25
Ammonia 35
n-Butyl acetate 710
Butyl mercaptan 35
Diethylamine 75
Dimethylamlne 18
Ethylamine 18
Ethyl mercaptan 25
Isopropylamine 12
Methylamine 12
Methyl mercaptan 20
Triethylamine 100
*The Threshold Limit Values refer to airborne concentrations under which
it is believed that nearly all workers may be repeatedly exposed with-
out adverse effect.
DOCTRINE OF NUISANCE
Ownership of land includes the right to impregnate the air with odors,
dust and smoke, pollute the water and make noises, provided these actions
do not substantially interfere with the comfort of others or injure the
use and enjoyment of their property. Whenever a person uses his land in
such a way as to violate this principle, he may be guilty of maintaining
a nuisance. Thus, the doctrine of nuisance acts as a restriction on the
right of an owner to use his property as he pleases and is applied to a
series of wrongs which may arise from an unreasonable, unwarranted or
unlawful use of his property which produces annoyances, inconveniences,
discomfort or hurt that the law will presume to be a damage. What con-
stitutes a nuisance in a particular case must be decided upon the facts
and circumstances of that instance.
11
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Nuisance has been classified as either public or private. A nuisance
is said to be public when the public at large or some considerable por-
tion of it is affected or when the act is done in violation of law.
When a public nuisance is involved, legal action may be brought by a
public official. A private nuisance generally affects only one person
or a specific number of persons and it is a ground for a civil proceed-
ing only. In most cases, livestock odor conflicts have been of this
latter type.
The fact that a business is carried on carefully and in accordance with
the ordinary methods employed in that business does not relieve the own-
er or person responsible from liability to a neighbor if that business
causing the nuisance is unreasonable and constitutes a nuisance. Paulson
states that a livestock feeding operation, in itself lawful, is not a
nuisance per se. When it interferes with another's use and enjoyment
of property or injures that property, it may become a nuisance by virtue
of the way it is maintained or operated. The precise degree of discom-
fort that must be produced to constitute a nuisance must be decided upon
the basis of being reasonable or unreasonable.
For the odor of a livestock feeding operation to be considered a nuisance,
the stench must be offensive to the senses and materially interfere with
o
the comfortable enjoyment of property within the area. It is not neces-
sary that the odors should be harmful or unwholesome. It is sufficient
if they are offensive or produce such consequences, inconvenience or dis-
comfort as to impair the comfortable enjoyment of property by persons of
ordinary sensibility.
A person who suffers damages or feels that he suffers damages because of
the odor of livestock operation has two courses of action open to him:
a suit for damages and a suit to enjoin or abate the nuisance and he may
Q
pursue either or both. The remedies of injunction or abatement are gen-
erally considered by the courts as being harsh. Normally only that part
of the operation which amounts to a nuisance will be abated or enjoined.
When the nuisance results only because of the method of operation or
12
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manner in which the business is conducted, the decree will be formed only
to prevent that particular method or manner rather than prohibiting com-
pletely the use of the property by the person creating the nuisance. It
is an essential element for injunctive relief that the annoyance or in-
jury be continuous or recurrent. The use of premises which amounts to
a nuisance may be enjoined, however, if it reasonably appears that such
annoyances or injury will be recurrent.
To be liable for actual damages one need only create or commit a nuisance.
The party injured is normally allowed to show the best or most advanta-
geous use for which the property is to be used; this is then used as a
basis for determining the amount which would be adequate and fair compen-
Q
sation. Punitive damages are allowed only when it can be shown that
one has created and persistently maintained a nuisance with a reckless
disregard for the rights of others or when he has reason to believe that
his act may injure another and does it in deference to the rights of
others. The mere commission of an act justifying an award of actual
damages is not sufficient to justify the award of punitive damages as a
Q
penalty.
Several court cases involving livestock production odors have been heard
in recent years. A limited number of these cases are listed in Appendix B.
The litigation experiences of five livestock and poultry producers were
summarized by Willrich and Miner. They listed the major causes of con-
flicts that precipitated these civil proceedings as follows: noncompli-
ance with zoning regulations; offensive odors exhausted from totally en-
closed, mechanically ventilated buildings in which manure and waste feed
were decomposing anaerobically; offensive odors released from anaerobic
lagoons; offensive odors originating from manure decomposing on open lot
surfaces; surface water pollution caused by runoff; or transport of man-
ure from open lots. Other causes included objectionable noises, exces-
sive flies and rodents, manure spillage on a public highway and suspected
ground water pollution.
13
-------
The probability of a livestock or poultry producer becoming involved in
10
court litigation can be minimized by heeding the following suggestions.
(a) The production unit and associated waste handling and disposal facili-
ties must comply with zoning regulations and all other applicable
water pollution control and environmental quality regulations.
(b) Provide an adequate separation distance between odor source and the
points where the odor could offend others unreasonably and thus con-
stitute a nuisance. Provide an adequate buffer zone for odor dissi-
pation in all directions from the odor source, not just in the pre-
valing wind direction.
(c) Use waste management methods that minimize release of offensive
odors, particularly if the available buffer zone is inadequate for
normal dissipation by natural conditions.
(d) Use waste management methods that control the release of potential
pollutants into the surface and underground waters and the produc-
tion of flies, rodents, and other pests.
(e) Avoid or otherwise screen or isolate from public view any unsight-
liness that might suggest the productional facility could be a
source of odor, flies, or other causes of nuisance or material that
could cause environmental quality degradation.
(f) Practice the negative golden rule. Don't do to others as you would
not like them to do to you.
14
-------
SECTION III
ANIMAL RESPONSE TO ODORANTS
Because of the difficulties in measuring the strength of odors, no data
correlating odors to animal response exists. There has been, however,
considerable work reported which establishes the deleterious effects of
air pollutants on the health and performance of livestock. This sub-
ject was reviewed in great detail by Lillie. The material which follows
will deal only with those gases and vapors associated with livestock pro-
duction and their effect on animals.
AMMONIA
Ammonia in the atmosphere at levels tolerated by man (less than 25 ppm
3
or 17 mg per m ) does not constitute an air pollution crisis to domestic
animals. Higher levels created by poultry kept under poor management
practices have been known to produce an eye disorder known as keratocon-
junctivitis and to affect the overall performance of poultry, especially
with high temperature and high relative humidity. Avian leukosis was
not influenced by ammonia. High levels of nutrition counteracted the
detrimental effects of ammonia as did proper management and ventilation
practices.
A study, conducted by Charles and Payne, indicated that at 18 C and
at 67 percent relative humidity the use of atmospheres containing 105 ppm
of ammonia (by volume) significantly reduced egg production after 10-weeks
exposure. No effects were observed on egg quality. When White Leghorn
hens were housed at an environmental temperature of 28 C, body weight
decreased. The decrease in live weight was greatest at the high ammonia
concentration of 102 ppm and was significant after only one week exposure
to the ammonia. Exposure to ammonia further reduced the food intake of
the animal as compared to those housed in a low ammonia environment. In
a subsequent trial, a high protein, vitamin and mineral diet prevented
the onset of harmful effects of ammonia on egg production, even though
food consumption fell significantly.
15
-------
Duroc pigs were subjected to four levels of ammonia air contamination
(approximately 10, 50, 100 and 150 ppm by volume) in a study by Stom-
12
baugh, league and Roller. The trials were conducted under environmental
conditions of 21.2 C temperature and 77 percent relative humidity.
Ammonia concentrations had a highly significant adverse effect upon feed
consumption and average daily gain. However, there was no significant
effect upon efficiency of feed conversion.
12
Preceeding the first trial, Stombaugh, Teague and Roller placed a 30 kilo-
gram (66 pound) gilt in an ammonia concentration of approximately 280 ppm
for 36 hours. When first placed in the compartment, frothing of the mouth
was observed and there were excessive secretions around the nose and mouth.
After approximately three hours, the frothing disappeared. Excessive secre-
tion around the nose and mouth, a short and irregular respiratory pattern,
occasional sneezing, and occasional shaking of the head persisted. After
36 hours in this environment, convulsions occured and breathing was extremely
short and irregular. At that point the ammonia supply was turned off, and
the compartment completely ventilated. Although the pig continued to have
convulsions for at least three hours, its condition improved. Seven hours
after convulsions ceased, except for occasional sneezing and shaking of
the head, the animal appeared completely normal. This experience indicated
that an ammonia concentration of 280 ppm was too high to be used in their
experiments.
HYDROGEN SULFIDE
Hydrogen sulfide is a highly lethal gas to man and to livestock. Incidents
of animal deaths attributable to hydrogen sulfide toxicity have been re-
ported, particularly when manure storage tanks beneath slotted floors have
been agitated prior to pumping to a tank truck or an irrigation system.
Lillie provides documentation of three instances in which swine were killed
while manure storage tanks were being agitated. Measurements have been
taken indicating that hydrogen sulfide concentrations after a brief period
of agitation can reach concentration in excess of 1,000 ppm which is well
over the 500 ppm level considered toxic to humans.
16
-------
MIXED AIR POLLUTANTS
The effect of a manure storage tank located beneath and vented to an ani-
mal confinement facility is to increase the concentration of hydrogen sul-
fide, ammonia, carbon dioxide and methane within the atmosphere. Agitation
of the liquid manure slurry results in a rapid increase of H S and CCL gases
above the levels at which they are normally toxic to livestock. The clini-
cal symptoms of these gas toxicities are: (a) methane becomes explosive
in concentrations of five to six percent; (b) CO- produces palpitation at
the 10 percent level and a narcotic action that often results in death at
the 25 percent level; (c) ammonia causes irritation of eyes and respiratory
mucous membranes at the 0.01 percent level and becomes a health hazard
at a level of 0.05 percent; (d) concentrations of 0.002 to 0.01 percent
H,,S irritates the eyes and produces dizziness within 30 minutes, a 0.05
percent level affects the nervous system and death occurs after 30 min-
utes of inhalation, and inhalation of air containing 0.09 to 0.1 percent
H,,S produces instantaneous death.
17
-------
SECTION IV
THEORY OF ODOR PERCEPTION
Each of the five senses is used to bring us information about our environ-
ment. The ability to touch, taste, hear, see and smell brings us into
contact with our external world in such a way as to give us a better under-
standing of its status and changes. The response to these senses is essen-
tially a personal reaction. Whether a sound is pleasant, a feel is satis-
fying, a taste is enjoyable, a scene is beautiful, or a smell is desirable
is essentially a personal response based upon our cultural background and
our individual disposition of the moment.
The senses of touch, taste, hearing and sight all measure environmental
parameters which are also measurable by other techniques as shown in Table 6.
The sense of smell is unique in that no mechanical or chemical alternative
device exists for measuring the odor. Thus, odor is essentially a subjec-
tive phenomenon for which no quantitative standard of comparison exists.
The human nose is the basic detector in odor analysis. It may be supple-
mented in some cases by other instruments, but there is no replacement for
it even though the complexities of its functioning are not thoroughly under-
13 14
stood. Moulton stated that the final approach in odor and flavor identi-
fication is "a bioassay based on stimulation of the human nose. But the
behavioral response of a man is not a simple objective index of olfactory
sensitivity. It is the end product of a complex flow of interacting events,
molded by the needs and experiences of the individual—by the input of many
classes of information. Yet, in the last analysis, there is no adequate
substitute."
Measurement of odor intensity and quality must be preceeded by an understand-
ing of the way the nose functions to distinguish one odor from thousands of
others. A simplified sketch of the odor sensation process follows. Infor-
mation of greater detail may be found in The Chemical Senses by Moncrieff.
19
-------
Table 6. THE HUMAN SENSES, EXAMPLES OF PARAMETERS MEASURED AND ALTERNATE
INFORMATION SOURCES
Sense
Parameter measured
Alternate device
Unit of measurement
Sight Color, intensity
Sound Pitch, intensity
Taste Saltiness, sour
Touch Temperature,
hardness
Smell Odor
Colorimeter, light Wave length, lumens
meter
Tuning fork, Frequency, decibels
microphones
Chemical titration mg/1, pH unit
pH
Thermometer
None
Degree
None
Figure 4 depicts the nasal cavity in the human head. Inspired air typically
travels into the nostrils, through the turbinate area and down the throat
to the lungs. Normal breathing will cause only a small portion of the air
to reach the olfactory cleft and the olfactory nerves, located high in
the nasal cavity. A "sniff", characterized by a short burst of air inspired
at a rate greater than normal breathing, brings about extensive turbulence
and diffusion to all parts of the cavity. Odor sensation is much more ob-
vious from a concerted sniff than from the normal breathing rate.
The olfactory nerve cells, shown in Figure 5, are located in the olfactory
cleft area. The total olfactory reception area in the adult human is about
two square inches. The olfactory cells are long and narrow; they are or-
iented perpendicular to the surface of the receptor area. The cells are
pigmented yellow or yellow-brown. On the exposed end of the nerve cells
are five to eight olfactory hairs which extend into or through a mucous
layer which coats the surface of the mucous membrane. Surrounding the ol-
factory cells in the mucous membrane are the sustentacular cells which
support and insulate the nerve cells. Axons, originating at each nerve cell,
pass through the membrane at the base of the mucous layer and carry a mes-
sage to the glomeruli.
It is believed that the olfactory hairs are the means of reception of the
"signal" of the odorous molecule. A chain of events follows which instan-
taneously gives odor perception. The hairs are kept moist by the mucous .,
20
-------
OLFACTORY
CLEFT
NOSTRILS
SPINAL CORD
Figure 4. Human nasal cavity
SUSTENTACULAR
CELL
BASEMENT
MEMBRANE
HAIRS
RECEPTOR CELL
AXON FIBER
Figure 5. Olfactory mucosa
2 i
-------
layer. An excess of the mucus as in the case of a head cold can incapaci-
tate the hairs and the sense of smell. There are different kinds of odor
receptor cells—cells that respond to different odor stimuli.
Moncrieff describes the mechanism of olfaction in six stages:
(a) The molecules of a volatile substance are continually lost to the
atmosphere.
(b) Some of the molecules, inspired with air into the nasal cavity, are
directed to the olfactory receptors. The aid of a sniff is benefi-
cial but not essential.
(c) The odorous molecules are adsorbed on appropriate sites on the olfac-
tory nerve cells.
(d) The adsorption is accompanied by an energy change.
(e) An electric impulse, generated by the energy change, travels from the
olfactory receptor to the brain.
(f) The brain processes the information and transmits the sensation of
smell.
MECHANISMS OF PERCEPTION
A precise relationship between chemical composition and odor would make
it possible to predict accurately the odor of an unknown compound or to
formulate a compound with a required odor. Recent findings have shown
that odor is closely associated with molecular configuration, and this,
according to Moncrieff is only half the story of odor perception. The
other half consists of the receptor system and the brain of the person
doing the smelling.
An acceptable odor theory must account for odor phenomena. Some of these
are listed here:
(a) Only volatile substances are odorous.
(b) Air movement into the nasal cavity is necessary to feed the receptors,
(c) If air movement in the nasal cavity stops, odor sensation vanishes.
(d) Water, though having the characteristics of other odorants, has no
odor.
22
-------
(e) Gases such as oxygen and nitrogen have no odor.
(f) Exposure to an odor produces a high initial response and a declining
response with continued contact. (Adaptation).
(g) A strong odorant completely exhausts the capacity to perceive the odor
in two to three minutes. (Fatigue).
(h) A change in odor sometimes occurs on dilution of the odorant.
(i) Some animals have a better developed sense of smell than humans.
(j) Isomers (having the same chemical composition) have widely differing
smells.
(k) Compounds having widely differing chemical compositions have similar
smells.
(1) Some odorants are perceived at a concentration of one millionth that
of others.
The theories of odor perception differ essentially on the method by which
the "message" of the odorant is transmitted to the olfactory nerve. The
primary theories have proposed (a) chemical reaction, (b) physical adsorp-
tion and (c) molecular vibration as the cause of initial stimulus.
The chemical theory can be largely discounted on the basis of work done
on a freshly severed sheep's head. An odorant was passed through the
nasal cavity of the head and collected and analyzed after passage. The
first collection of air which had carried the odorant into the sheep's
head contained none of the odorant. (The odorant had been adsorbed onto
the receptor cells in the head.) After a short time, the air passing
through the head contained a concentration of odorant equal to that enter-
ing. (The receptor sites had been saturated and any particles adsorbed
only replaced particles desorbed.) The odorant supply was cutoff and the
airstream continued to circulate through the nasal cavity until no odorant
was detected in the exit air. (The only odorant remaining in the head was
adsorbed onto the receptor areas.) After a period of time, up to several
hours, the air flow was again started. No odorant was added. The dis-
charged air again contained the odorant in its original form. (The odor-
ant desorbed from the receptor sites was unchanged. No chemical action
had taken place. The process of adsorption is essential in odor perception.)
23
-------
Events in this experiment are not, however, supported by the contention
of Davies that particle retention time on the receptor surface is on
—8
the order of 10 seconds and that a chemical reaction not dependent on
the reactivity of the odor molecule occurs.
18
The stereochemical theory of Amoore was first introduced in 1952. This
theory was based upon a fit between an odor molecule and a "socket" at
the receptor site in the nose. Seven types of receptor sites were pro-
posed to serve the seven primary odors—ethereal, camphoraceous, musky,
floral, pepperminty, pungent and putrid. Other odors resulted from combina-
tions of the primary odors. Amoore has more recently altered his theory
to account for a two-dimensional fit rather than three-dimensional.
Molecular silhouette or cross-sectional area is the important steric
19
characteristic of the odorant. Odor perception is initiated by an
energy change brought about by the adsorption of the odorant molecule
on the olfactory nerve.
20
The vibrational theory for human olfaction was introduced by Dyson.
The theory proposed that odorous substances possess intra-molecular vi-
brations of such periods as to produce Raman shifts between 1400 and
3500 cm"1.
21 22
Since 1954, the idea has been furthered by Wright ' who suggests
that the Raman shifts of odorous substances occur at frequencies less
than 700 cm . It is the vibrations of this range that are most likely
to be active at body temperature. The vibrational theory concludes that
odorant molecules have "odor-active" molecular vibrations which are best
evaluated by both the Raman and infra-red spectroscopy. These important
vibration frequencies "fit" specific receptor sites in the nose (along
with a steric fit) thus providing the initial stimulus for odor perception.
23
Davies and Taylor presented the penetration theory. Odor perception
according to this theory depends upon two basic parameters:
(a) The partition coefficient of the substance between air and a water-
oil interface. This relates to the adsorption-desorption properties
of the odorant on the receptor site.
24
-------
(b) The cross-sectional area of the molecule. This relates to the
characteristics of the puncture of the olfactory nerve by the odor-
ant adsorbing on the receptor site.
Odor reception is initiated when the molecule adsorbs onto the olfactory
nerve causing a puncture of the surface lipoid membrane. Residence time
—A
of the odorant substance on the nerve is on the order of 10 seconds.
The time required for the puncture to heal is longer—on the order of
10 seconds. In the interval between desorption and healing of the
puncture an exchange of Na and K ions occurs. This exchange, brought
about by an excess of Na+ on the exterior and K on the interior of the
membrane, is the stimulus for the olfactory perception process. More
24
recent work on the penetration theory by Theimer and Davies has added
a third parameter for odor dependence—the length to breadth dimension
ratio of the molecule.
These theories are the basis for most of the research related to olfactory
perception in recent years. Two points of agreement exist in these theor-
ies: (a) the process is initiated with the adsorption of the odorant
molecule on the olfactory nerve and (b) the cross-sectional properties
of the molecule are a controlling factor. Again, the primary difference
is the manner by which the characteristic odor of the molecule is trans-
lated to the olfactory nerve. It is feasible that all of these theories
might be involved in the actual odor perception reaction.
Finally, the odorant substance must possess certain characteristics if
it is to be subject to the theories presented: (a) the substance must
be sufficiently volatile that molecules can be transported to the nasal
orifices; (b) solubility in the lipoid material of the mucous membrane
is essential. Solubility in water is helpful; and (c) the odorous sub-
stance must be able to be adsorbed onto the sensory nerve.
ODOR STRENGTH
Accurate characterization of an odor includes reference to its strength,
or intensity, and its quality. American Society for Testing and Materials,
25
-------
25
"Manual on Sensory Testing Methods," effectively describes the ground
rules for conducting odor strength and quality tests. The manual states
the requirements for the physical facilities, the test subjects and the
samples to be tested. The kinds of tests that may be applied are dis-
cussed along with procedures for analysis of the data. The manual does
not, however, describe the detailed procedure by which the individual
tests must be conducted. Such details are dictated by the kind of mater-
ial and the characteristic of the odorant being judged.
The most common method of measuring odor intensity is by dilution to
extinction. The odorant is diluted with an odor-free medium until its
odor can no longer be detected. The greatest dilution at which the odor-
9fi
ant is just barely detectable is termed the threshold value. Baker
compared four common procedures for determining the threshold value of
an odorant in odor-free water dilution:
(a) Standard Method, STD; five flasks containing serial dilutions plus
one "catch trial" blank.
(b) Consistent Series, CS; five flasks containing serial dilutions plus
two blanks.
(c) Triangle Test, TT; three flasks at each dilution level, two of which
are blank.
(d) Short Parallel, SP; two flasks at each dilution level, one of which
is blank.
The tests were run using two odorants, n-butanol and m-cresol. The re-
sults showed that the tests in order of decreasing sensitivity were TT,
CS, SP and STD. Baker, however, points out that no test is obviously
superior when performed under controlled conditions with trained person-
27
nel. Burnett and Dondero reported on a modified procedure for threshold
odor determination.
Threshold odor levels are also measured using odor-free air as a carrier
and dilution medium. Equipment for the air-dilution method is more intri-
cate and expensive, but the results are more reliable as a measure of
true odor intensity. A number of writers have reported on odor threshold
26
-------
15 27 28
determinations with the air dilution procedure. * ' Suprathreshold
odor intensities can be judged directly. The odorous unknown is compared
with a similar or like odorant of known intensity. The observer makes
29
an intensity judgment based on the comparison. Jones and Waskow and
30
Stone described methods to utilize this test practice. Either liquid
or air-dilution procedures may be used to make the comparisons. Supra-
threshold odor-intensity judgments lack the reliability of the threshold
level determination.
Odor intensities are stated in terms of the odor intensity index, Oil, or
the threshold odor number, TON. The two values are related according to
the equation
2011 = TON (1)
Oil is defined as the number of times an odorant must be diluted by half
with odor-free medium until the threshold is reached. TON is defined as
the greatest dilution of the odorant with odor-free medium until the
threshold is reached. Most writers seem to prefer to use Oil rather than
TON. Certainly an Oil value of 15 is less cumbersome and easier to grasp
than the equivalent TON value of 32,768.
Odor-intensity testing can be objective in nature if a sufficient number
of qualified, properly prepared observers are used and procedures and
conditions of the test are standardized. Odor threshold measurements
are more objective than suprathreshold measurements. ASTM stated that
the minimum number of observers for any test is five since any fewer num-
ber places too much dependence on the response of any individual. The
subjects must pass a preliminary screening to assure that they are capable
31
of making a normal response to the stimuli to be presented. Swets
emphasizes the need to inform the observer as fully as possible concern-
ing the nature of the judgments desired, the test procedure and the con-
trols to be employed. Uncertainty plays a big role in reducing the
effectiveness of the subject and, consequently, the validity of the re-
sults. Swets further suggests the inclusion of a large number of catch
trials (trials which contain no odorant) to insure the certainty of a
positive decision.
27
-------
ODOR QUALITY
Odor-quality references are often made by comparing the odor with an odor
that is familiar. The odor is "like coffee", "like new-mown hay" or
"like a characteristic poultry odor". The judgment of "characteristic
poultry" would depend on past experiences. This recollection may result
from a light, well-ventilated house with little more than the smell of
must or feed, or it may have been a highly populated house with poor ven-
tilation, high humidity and concentrated ammonia. One's interpretation
could include a wide range of quality values.
Many attempts have been made to produce a list of basic odor classes that
would describe the qualities of all other odors. These have been report-
14 15
ed by a number of authors. ' Five of these lists are presented in Ta-
ble 7. Classes of similar qualities are placed on the same line.
Table 7. BASIC ODOR QUALITY CLASSIFICATIONS AS DESCRIBED BY FIVE AUTHORS
15
Zwaardemaker
1895
Ambrosial
Balsamic or
fragrant
Ethereal
Aromatic
Empyreumatic
Alliaceous
Caprylic
Henning Crocker and
1916 Henderson, 1927
Flowery, Fragrant
resinous
Fruity
Spicy
Burnt Burnt
Foul
Caprylic
Amoore
1952
Musky
Floral
Ethereal
Camphora-
ceous
Minty
Davies
1965
Musky
Floral,
cedary
Ethereal,
fruity
alcoholic
Camphora-
ceous ,
aromatic
Pepper-
minty
Almond
Repulsive
Nauseating,
foetid
Acid
Putrid
Pungent
28
-------
Qualitative odor testing is widely used in the food and perfume indus-
tries. Use of qualitative odor testing in livestock waste research is
limited. The test is often made by comparing the unknown with a known
odorant of similar or dissimilar quality in paired comparisons. The
observer then makes a judgment of the degree of similarity.
Odor-quality testing lacks the desired objectivity of the odor threshold
determinations. Quality tests require observer judgments relative to a
known odorant and subjectivity is unavoidable. To maximize the validity
of the test, the preparations of the physical facilities, the samples, and
25
the subjects as outlined by ASTM are of utmost importance.
LIMITATIONS OF ODOR TESTING
The limitations of odor testing result from the existence of odor phenomena
and the preferences (or subjectivity) of the observers. The sources of
these limitations will be discussed individually. It should be apparent
how each limitation can enter into the interpretation of odor test results.
Adaptation
Adaptation is the adjustment of the observer to the odor stimulus. The
level of sensation diminishes with time even though the stimulus is ap-
plied at a steady rate. Observers who enter the vicinity of livestock
buildings or yards soon lose the ability to make unbiased odor judgments
about odorants similar to those of the immediate environment. The rate
of adaptation varies with the strength of the stimulus. Moncrieff dem-
onstrated the effect of adaptation. A subject who first took a sniff of
pure acetone could recognize nothing less than 5.0 percent acetone with
a second sniff. This is 170 times the threshold concentration. The
effect of a dissimilar odor was not so great. After smelling pure ace-
tone, n-butanol could be recognized at 0.06 percent or 12 times the threshold
concentration.
2ft
Adaptation effects were also reported by Baker who tested the influence
of light, background odor on odor-intensity tests. Background odor simi-
lar to the odorant tested reduced the Oil slightly while a background odor
29
-------
dissimilar to the odorant tested produced a slight increase in the Oil.
Fatigue
Fatigue is the result of adaptation. Exposure to a strong odorant may
completely exhaust the capability to sense the odor. Fatigue develops
gradually, with an exposure of two to three minutes required for total
exhaustion. Recovery after removal of the odorant requires about the
same length of time. Fatigue is selective. That is, fatigue to one
odor will reduce sensitivity to similar odors, but does not produce fa-
13
tigue for all odors.
Odorant concentration
Changes in odor quality sometimes occur due to dilution. For example,
concentrated furfuryl mercaptan has a nauseating odor but is reminiscent
of the aroma of coffee when greatly diluted. Moncrieff theorized that
this effect may result from a substance comprised of more than one recog-
nizable odor where each odor has a different threshold.
Moncrieff reported the concept of limiting intensity. The concept
says that the human nose cannot distinguish between odorant concentra-
tions greater than a saturation level. The reasoning behind the concept
(which heavily supports the adsorption theory of odor) is that the re-
ceptor sites become filled with odorous molecules and an increase in the
number of molecules inspired causes no increase in sensation.
Standard procedure for odor threshold testing utilizes serial dilution
with each succeeding dilution 50 percent of the one before. Fractional
.15
26
dilution is not justified. Baker reported variability of about one
Oil unit with the four threshold test procedures that he used. Moncrieff
stated that an increase of about 30 percent in odorant concentration is
necessary to produce a perceptible sensation.
Both air and liquid dilution media are employed in odor testing. The
liquid is usually odor-free water, but alcohol in combination with odor-
free water has been used when the odorant was not soluble in water.
30
-------
Definition of the dilution system and other test conditions are important
28
in reporting results. Sobel stated that different threshold values
are obtained from air and water dilution methods for the same odorant.
An awareness of the significance of air and liquid dilution systems is
desirable. A water dilution system dilutes the source of the odor until
the emitted odor is just detectable. This measures the odor-producing
capacity of the odorant. The air dilution system dilutes the odor pro-
duced until that odor can just be detected. This measures the strength
of the odor produced by the odorant. Both systems have application in
studying odor from livestock operations.
Mixtures
32
Rosen et al. listed four possible reactions for mixtures of two in-
dividually odorous components. In these equations, RA is the odor stimu-
lus of component A, R_. is the odor stimulus of component B, and R
a *
the odor stimulus from the combination of components A and B.
(a) Independence RA+B = RA °r ^B
(b) Antagonism or RA+B < RA °r
counteraction
(c) Addition RA+B = RA + ]
(d) Synergism RA+B > RA •*
Work of Baker26 confirmed examples of additivity, antagonism and synergism.
Jones and Woskow29 tested the odor intensity of two component mixtures
of odorants. They used all possible combinations of three similar odorants
and, also, of combinations of three dissimilar odorants. The odor magni-
tude of the mixes was not additive, nor was it an average of the two com-
ponents. The odor level of the combinations was somewhere between the sum
and the average. This reaction lies in a region not specified by the Rosen
32
et al. reactions RA+B < RA + ^B > A B '
31
-------
Moncrieff described counteraction (the mutual discrimination) of two
odors to the exteat that they are odorless in combination. Using low
concentrations of the odorants they tend to be additive, but with cer-
tain combinations of high concentration, the effect was no odor. Guadagni
33
et al. found that the combination of sub-threshold concentrations of
odorous components produced suprathreshold mixtures.
Without prior knowledge, the quantitative and qualitative outcome of the
reaction of the combination of two components is unpredictable. In addi-
tion, the type of reaction, according t<
to the concentration of the components.
tion, the type of reaction, according to Moncrieff, can vary according
Complex mixtures of odorants may not offer the same mysterious range of
reactions offered by two-component systems. Complex odorant mixtures
have direct application to the field of livestock odors where odors often
33
result from complex biological systems. Guadagni e_t^ ^3^. in testing
complex systems of up to ten odorants concluded that the reactions were
mostly additive rather than synergistic, antagonistic or independent.
This would be the anticipated result for complex systems where the more
common additive reaction outweighs the other somewhat unusual reactions.
In this case, "additive type reaction" refers to one that is additive in
nature and not strictly additive as in the reaction stated by Rosen. The
interpretation is that (using the two-component reference notation)
RAfB > RA
Temperature
The recommended temperature for comparative odor testing is 40 C. This
temperature was preferred by panelists as compared to temperatures of
21° and 60° C. The lower level produced "dead" samples while the high-
er level produced some steaming and gave fleeting initial responses
(probably due to the extensive removal of the more volatile odorants
present). An Oil increase of 1.4 units was noted in increasing the di-
luted odorant test samples from 21 to 60 C.
32
-------
Other temperature levels for odor testing are reasonable where odor in-
tensity and quality measurements are to be indicative of operative con-
ditions different from 40° C. The odor intensity determination for man-
ure stored under winter conditions might be made at 4 C, while odor levels
generated under summer or warm weather conditions might be reported at
20° C. Where odor levels are established strictly for comparative pur-
poses, the standard af 40° C would be desirable.
Anosmia and parosmia
Anosmia (odor-blindness) is a condition which affects about 10 percent of
the population. Partial anosmia, anosmia for a group of similar odors,
is more common than complete anosmia. Partial anosmia is much more like-
13
ly to exist without the knowledge of the afflicted person.
Parosmia (perversion of odor) is a second type of olfactory disease. The
parosmatic senses a different odor than the one put before him. The per-
verted odor is often an unpleasant one. The condition is likely to be
13
temporary.
Pungence
"Puneent" has been included as a basic odor type by some authors. This
18 22
odor is associated with strong acidic and basic smells. Two authors
proposed that pungence may not, in some cases, be a true olfactory nerve
response, but a sensation of pain caused by irritation of the trigeminal
nerves in the nasal cavity.
In general, man's sense of smell develops until the age of about 20. The
good sense of smell continues until the age of about 50 and then declines.
Venstrom and Amoore tested 97 normal subjects to determine the rate
of decline of olfactory sensitivity with age. The study showed that man
has a 50 percent reduction in the sense of smell in 22 years. This com-
pares with 13 years for a 50 percent reduction in sense of sight, 15 years
for sound, 29 years for taste and 60 years for touch.
33
-------
Moncrieff related that children have a greater tolerance for a fecal
odor such as skatole. He also states that man develops a taste for
partially-decomposed food such as aged meat and cheese as he grows older.
Children rank fruity odors highest for pleasantness while adults prefer
fragrant odors.
Sex.
Authors are divided on the theory that women are more sensitive, olfac-
torywise, than men. The case is well stated by the research of Venstrom
34
and Amoore who found that women were about one-quarter Oil unit more
sensitive to odor intensity than men but that this was not a significant
amount for the conditions of their study.
Moncrieff points out that men are more nearly unanimous in their pre-
ference fox pleasant odors while women are more unanimous in their selec-
tion of odors which are unpleasant. Women as a group think culinary odors
are more pleasant than men do.
Smoking
Like the battle of the sexes, the question of sensitivity of smokers is
34
unsettled. Again, the work of Venstrom and Amoore gives a good picture
of the facts by reporting that non-smokers were about one-fifth Oil more
sensitive to odor intensity than were smokers but that this was not sig-
nificant for the conditions of the test. It is necessary, however, that
smokers refrain from smoking for 15 minutes before the odor test.
Natural variation
According to Moncrieff olfactory capabilities among healthy persons
are fairly uniform. The primary difference is the form of the nasal pass-
ages. Additional variations, though slight, can result from any of the
myriad diseases and conditions which affect the state of the nasal cavity
and olfactory nervous system.
SUPPLEMENTARY INSTRUMENTS
The gas-liquid chromatograph, GLC, has been the most important instru-
ment in supplementing the capabilities of the human nose in odor research.
34
-------
While the nose can best determine the quality and intensity of simple
and complex odor combinations, the GLC can best fractionate and quantify
the odorant components involved. The capabilities of one do not replace
the capabilities of the other. Advancing technology has made possible
increased sensitivity of the GLC and, therefore, greater capacity to
identify the trace quantities of odorants in complex materials. A num-
ber of researchers have reported the use of the GLC for odor component
identification for livestock wastes. ' ' ' '
39
Kendall and Neilson compared the sensitivity of the GLC to the nose.
They found that their panelists could detect odorant concentrations 10
to 100 times more dilute than the GLC. Other types of chromatography,
though less sensitive, can also be useful in component identification
after separation.
Odometers of various forms have been developed to assist in test work.
The meters are of the general form that can make the necessary dilutions
of the odorant with odor-free air prior to inspiration. The meters have
been given such names as "osmoscope", "odormeter" and "osmometer". Des-
30
criptions and use of these instruments have been made by Stone ,
1 S 28
Moncrieff and Sobel.
Development of a "mechanical nose" which would eliminate errors of natural
variation and subjectivity in the human nose would greatly advance odor
research. The most important obstacle in such a development must be the
lack of understanding of the odor perception process of the human nose.
Even so, several researchers have made efforts to duplicate the human
nose.
In 1961 Moncrieff developed a mechanical nose. Many refinements were
added later. The instrument utilizes a pair of matched thermistors,
one of which has a thin protein film placed over it. As an odorant passes
over the thermistors, the unbalanced rates of adsorption on the protein
film and the glass coating of the other thermistor cause a temperature
differential. A flow of current between the thermistors caused by the
35
-------
41
unequal resistances is measured on a micro-ammeter. Friedman, et al.
adapted this type of mechanical nose for their work on energy changes
associated with odor perception.
42
In 1964, Rosano and Scheps reported on their efforts to develop an
artificial nose. These writers used an instrument which allowed simul-
taneous study of adsorption and chemical interaction. Their contention
was that enzymatic action must be considered in the odor perception process.
These attempts to further understand the function of the human nose and
to simulate it have met with some degree of success. Some of the responses
of the machines closely resemble those of the nose. It appears, however,
that the complexities of the human nose are impossible to duplicate.
36
-------
SECTION V
RELATIONSHIP BETWEEN ODOR AND pH
To exhibit its characteristic odor, an odorous substance dissolved in
water, must escape from the liquid phase. Ionized species have no vapor
pressure, thus, only the non-ionized species are effective in odor pro-
duction. Hydrogen ion concentration is the single most important variable
in determining the fraction of a substance in the non-ionized form. Us-
ing lime to control the escape, hydrogen sulfide is an applied example
of this phenomenon.
Quantification of this characteristic is best achieved by considering the
pK values. At a pH equal to the pK, one-half of the compound is present
in the non-ionized form. For acidic odorants, a decrease in the pH by one
unit causes the fraction of the non-ionized species to increase to 91 per-
cent. Increasing pH values result in the opposite effect. For basic
odorants, increasing pH values result in greater quantities being present
in the non-ionized fraction, thus in greater volatility. Table 8 includes
a tabulation of pH values for various odorants at which the compound is
50 percent ionized.
Table 8. pH VALUES FOR WHICH VARIOUS ODOROUS COMPOUNDS ARE 50 PERCENT
IONIZED AT 25° C 3
Acidic Compounds
Acetic acid
Butyric acid
Hydrogen sulfide
Propionic acid
pH
4.75
4.83
7.04
4.87
Basic Compounds
Ammonia
n-Butylamine
Diethylamine
Dime thy 1 amine
Ethylamine
iso-Butylamine
iso-Propylamine
Methyl amine
Propylamine
Triethylamine
Trimethylamine
pH
9.25
3.39
3.00
3.30
3.33
3.58
3.37
3.36
3.42
3.28
4.20
37
-------
SECTION VI
DESORPTION OF AMMONIA
Although ammonia is highly soluble in water, an equilibrium exists be-
tween the ammonia concentration in water and its partial pressure in
air. When manure or manure slurries, high in ammonia, are in contact
with air, desorption takes place. The driving force is the partial pres-
sure of ammonia in equilibrium with the liquid concentration; diffusion
across the gas film is the rate-limiting process. From these statements,
a modified Pick's Second Law expression can be written.
dw/dt - Ak P. (2)
g A
where dw/dt » rate of desorption
A - area of gas-liquid interface
k = diffusion coefficient
5
P. = equilibrium partial pressure of ammonia
The term, P., which defines the partial pressure of ammonia in equilibrium
with the liquid, can be expressed in terms of the ammonia concentration
in the liquid and Henry's Law constant for ammonia.
PA
H
where C™ - ammonia concentration (mg/1)
H - Henry's Law constant
Only that portion of the ammonia present in the non-ionized (NH») form
is available for volatilization. The fraction of the total ammonia con-
centration in the NH_ form is a function of the pH and temperature. As
shown in Table 9 the fraction F of total ammonia concentration present
as volatile NH_ is sufficiently small at pH values less than seven to
preclude significant volatilization. Values in Table 9 were calculated
from the following relationships :
39
-------
NH + HO <± Nfit" + OH (4)
J £• *T
= L»~4J [OH ]
[NH3J
' ' = [OH") (6)
F = l™^ = [OH~] (7)
(8)
Table 9. FRACTION OF TOTAL AMMONIA CONCENTRATION PRESENT AS NH3 AS A
FUNCTION OF TEMPERATURE AND pH*
l<]
K]
[M3]
+ [NH3]
[OH"] =_
^
[OH'l
^ + fOH'l
K
w
PH
7
8
9
10
10
0.0018
0.018
0.22
0.65
Temperature ( C)
20
0.0040
0.038
0.30
0.80
30
0.0081
0.075
0.45
0.89
* Values for K_ and K taken from Handbook of Chemistry and Physics
D W
A more useful expression is obtained by combining equations 2 and 3 while
substituting
dCXTTT -Ak CV_T
NH- g NH_
3
dt H
Analytically, measurements of ammonia include both NH, and NH^. The sum
will be called NH_ .
40
-------
More usefully, equation 9 can be written
<* * - "*V Cm* (12)
HH3 „ NH3
Equation 12 is frequently simplified to
*
dC
"3 -KC,, (13)
dt "3
K = -Ak F (14)
e
H
In equations 14 and 15, K is a desorption rate constant. When the natural
logarithm of the total ammonia concentration is plotted versus time, the
slope of the resulting line is equal to minus K.
FROM LIQUID POULTRY MANURE
Ammonia desorption from liquid poultry manure was studied by Hashimoto and
Ludington and the above analysis used to correlate their data. Desorp-
tion tanks were formed by inverting 19 1 (5.0 gal.) plastic carboys from which
the bottoms had been removed. The tanks were stirred and pH controlled.
This work indicated the rate of desorption is highly dependent upon air
velocity over the desorbing surface. Values obtained for Ak /H from
equation 14 ranged from 0.05 to 0.09 per hour at 21 C and 0.037 to 0.061
per hour at 10° C. Using these data, ammonia escaping from the surface
of their system at pH 8.0 and 20° C would lower the nitrogen concentra-
tion by 3.3 percent per day. At a pH of 9.0 the rate of decrease would
be 23 percent per day. Thus pH is extremely important in estimating the
rate of ammonia desorption.
FROM CATTLE FEEDLOTS
The escape of ammonia from cattle feedlot surfaces in northeastern Colo-
rado was studied by Hutchinson and Viets by placing dilute acid
41
-------
absorption traps at varying distances from cattle feedlots. Their re-
sults, summarized in Table 10, show significantly higher rates of ammonia
absorption in the vicinity of feedlots as compared to samples gathered
in other rural areas. The absorption of ammonia by the acidified absorbers
was twice that of distilled water.
Table 10. MEAN AMMONIA NITROGEN ABSORPTION RATES BY DILUTE ACID TRAPS
FROM 27 JULY 1968 THROUGH 27 FEBRUARY 1969 IN NORTHEASTERN
COLORADO45
Mean weekly ammonia
nitrogen absorption rate
Site description kg/ha
No feedlots within 3 km
Small feedlots (200 head) at 0.8 km
0.2 km east of 800 head feedlot
2 km east of 90,000 head feedlot
0.4 km east of 90,000 head feedlot
0.15
0.34
0.57
1.30
2.80
FROM DAIRY PENS
Additional work relative to the volatilization of ammonia from livestock
46
feeding areas was reported by Luebs, Laag, and Davis. Using dilute
acid solutions in both air sampling traps and surface traps, they measured
the concentration of ammonia plus amine nitrogen in the air near Chino,
California. It is in this area that approximately 400 dairies serving
the greater Los Angeles area are located. In this 15,500 ha (60-square-mile)
area there are 123,000 dairy cows, 7,500 heifers and more than 9,000
calves. Results of their sampling (shown in Table 11) demonstrate the
increase of ammonia and amine nitrogen concentration in the dairy area
compared to a nearby residential district. In Table 12 average weekly
absorption of ammonia plus amine nitrogen by acid surface traps is com-
pared for various areas near Chino, California. Their data indicated
that distilled water had an absorption rate equal to 58 percent of that
by acid surface traps, thus one may conclude the area near the Chino air-
port could be exposed to ammonia at a rate up to 220 kg/year/ha (200 lb/year/
acre) under the conditions measured.
42
-------
Table 11. ATMOSPHERIC CONCENTRATION OF DISTILLABLE NITROGEN (AMMONIA
PLUS AMINE) NEAR CHINO, CALIFORNIA46
Location
Sampled
Brackett Field, 11.2 km
(7.0 miles) upwind of
dairy area
Chino airport in dairy
area, 0.8 km (0.5 miles)
from cows
Date
02-25-71
05-04-71
10-05-71
02-24-71
03-03-71
03-05-71
10-05-71
Distillable nitrogen
concentration
3
ug/m
1
2
3
39
37
46
69
Table 12. AVERAGE WEEKLY ABSORPTION OF DISTILLABLE (AMMONIA PLUS AMINE)
NITROGEN BY ACID SURFACE TRAPS NEAR CHINO, CALIFORNIA, JANUARY
46
11 TO FEBRUARY 15, 1972
Average weekly
Location kg/ha
Dairy area, 0.8 km (0.5 miles) from
cows
Urban area, 11.2 km (7.0 miles) NW
of dairy area
Poultry and citrus area, 34 km (21
miles) E of dairy area
Dryland agricultural area, 51 km
(32 miles) E of dairy area
National forest, 80 km (50 miles) SE
of dairy area
10.5
0.31
0.27
0.20
0.02
absorption rate
Ib/A
9.40
0.28
0.24
0.18
0.02
Amine nitrogen comprises between five and 10 percent of the total nitrogen
absorbed by acid surface traps in the dairy area, according to a limited
46
number of analyses done by Luebs, Laag and Davis. Because the odor of
amine compounds is detectable at concentrations less than one ppm in air,
they concluded amines were undoubtedly important relative to odors from
animal waste.
A direct relationship was found between the concentration of ammonia plus
amine nitrogen and the evaporation rate as measured from their sampling
43
-------
traps filled with 0.01 normal sulfuric acid. Thus, these data demonstrate
the greater volatilization of ammonia and other distillable nitrogen com-
pounds from dairy corral surfaces as evaporative potential increases.
This conclusion was also supported by the fact that the amount of nitro-
gen measured tended to be higher when air temperature was high and rela-
tive humidity was low. Secondly, ammonia concentrations were greater
during dry periods after the corrals had been wetted by rain.
FROM ANAEROBIC LAGOONS
An anaerobic lagoon receiving swine waste was analyzed for ammonia desorp-
47
tion by Koelliker and Miner. This lagoon was operated as a flow-through
system with a theoretical detention time of about 60 days. The lagoon had
a surface area of 2,700 square m (29,000 square ft). A mass balance on the
lagoon had indicated that from November 1, 1969 to October 31, 1970,
5,600 kg (12,400 Ib) of nitrogen were introduced into the lagoon from the
swine waste. During this same period, 2,100 kg (4,700 Ib) of nitrogen were
removed from the lagoon with wastewater for application to cropland. Be-
cause the lagoon water level was lower in 1970 than in 1969, there was a
net decrease of 91 kg (200 Ib) in the accumulation within the system.
Thus, 3,600 kg (7,900 Ib) of nitrogen escaped from the system, apparently
because of ammonia desorption. Their data for the rate of ammonia desorp-
tion were correlated as follows:
d(NH3-N) =
"It 1 g
47
In this expression, K can be approximated by the formula:
K = 2.6 x loV'V1'4 (17)
where
V = air velocity in ft/second
T = temperature in degrees Kelvin
P.P = partial pressures of ammonia in the liquid and gas phases,
° respectively
K, the overall rate transfer coefficient has units of
pounds/day-square ft-atm
44
-------
SECTION VII
IDENTIFICATION OF ODOROUS COMPOUNDS
Considerable effort has been expended in identifying compounds evolved
by anaerobically decomposing manure. This work has largely involved con-
centrating the specific chemical gases being evolved into some absorbing
solution or condensing trap followed by chromatographic analysis of the
accumulated material.
POULTRY MANURE
The odor of fresh and accumulated poultry manure was chromatographically
analyzed by Deibel. He found butyric acid, ethanol and acetoin (3-hy-
droxy-2-butanone) to be the chief volatile components of decomposing ma-
nure while fresh manure was found to be devoid of these compounds.
To identify the volatile compounds of odor importance produced by chicken
Oc
manure, Burnett trapped gases in a collection column submerged in an
acetone dry ice bath. A variety of column packings and temperature con-
ditions were used to effect the necessary separations. When 0.5 micro-
liter of prepared condensate was injected directly into the gas chromato-
graph, six peaks were obtained which were identified as acetic, propionic,
iso-butyric, n-butyric, iso-valeric and n-valeric acids. The butyric and
valeric acids have very disagreeable odors.
35
As part of the same project, Burnett also injected chloroform extracts
into a chromatograph fitted with an SE-30 column. Indole and skatole
were identified by retention time comparisons with authentic compounds.
The detection of the nitrogen heterocyclic compounds, indole and skatole,
is significant because of the strong, harsh odors of these compounds.
Both indole and skatole are very tenacious odorants which tend to cling
to clothing and other articles and to persist for long periods. Burnett
found approximately 18 times more skatole than indole and concluded that
skatole was probably responsible, in part, for the tenacious character of
poultry waste odor.
45
-------
35
Using additional concentration techniques, Burnett tentatively identi-
fied several additional compounds from poultry manure. These were com-
pared with retention times of known compounds and evaluated by an odor
panel and postulated to be mercaptans and sulfides. Thus, his conclusion,
which is compatible with those of other researchers in this area, indi-
cated that animal manure odors are a complex mixture of organic compounds
with characteristics mainly contributed by numerous chemical groups in-
cluding the organic acids as well as sulfur- and nitrogen-containing com-
pounds.
A direct relationship between odor level and the volatile fatty acid con-
49
tent of liquid poultry manure was found by Bell. Fatty acids were mea-
sured according to the procedure outlined in Standard Methods. He sug-
gested an acceptable level based on odor control as being 0.1 percent or
less of fatty acids in liquid manure.
The microbiological-chemical changes occurring in poultry manure during
27
storage were studied by Burnett and Dondero. In their studies, dry
manure, 75 percent moisture, and wet manure, 85-90 percent moisture,
were stored for periods of up to 40 days. They monitored the chemical
and biological changes taking place within the stored material as well
as the composition of gases produced. They found the uric acid content
of dry manure in storage dropped rapidly during the first seven days.
The amine nitrogen content of the manure rose during the first seven days
and remained at a value of roughly 0.5 mg/g dry weight of manure for the
next seven days. Between day 14 and 22 the value dropped back to approxi-
mately the initial amine nitrogen concentration. Ammonia evolution was
initially low but rose to a maximum value after about six days, then fell
again.
A marked increase in odor intensity was noted in the liquid manure after
approximately 15 days. The uric acid content fell rapidly as was the
case with the dry manure. The ammonia content of the liquid rose rapidly
from approximately 100 mg/1 at the start of the experiment to a value
of approximately 1500 mg/1 after 10 days. Beyond this time the ammonia
46
-------
content remained essentially constant. The concentration of soluble sul-
fides began to rise after approximately 17 days of liquid storage. This
increase in soluble sulfides coincided with the dramatic increase in odor
concentration. Although methane-producing bacteria were present from the
start, they did not begin to proliferate until after 28 days of storage.
Their earlier growth may have been inhibited because of the large, volatile
organic acid concentration which developed during the early stages of stor-
age. Volatile organic acid concentrations increased to 1600 mg/1 by the
fourth day and remained at that level or higher for the next two weeks. The
volatile organic acid concentration then decreased, allowing the methane
bacteria to grow.
A series of studies utilizing White Leghorn laying hen manure was conducted
by Ludington, Sobel, and Hashimoto in which 75 g of manure was put
into a five gal. carboy for study. In one trial the manure was placed in
the carboy without additional water (25 percent solids) and in the second
trial the manure was diluted three to one with distilled water and the mix-
ture (6.0 percent solids) was placed in the carboy. Air at the rate of
28.3 1/hr (1.0 cu ft/hr) was passed through the carboys. The exit air was
then analyzed for carbon dioxide, ammonia, and hydrogen sulfide. In addi-
tion, odor panels made frequent observations on both systems to determine
the strength of the odor and the odor characteristics. Both systems pro-
duced approximately six g of carbon dioxide daily. The undiluted system
released 0.8 g of ammonia per day. The production and release of hydrogen
sulfide was larger in the diluted than in the undiluted system. Results
of these studies are in Tables 13 and 14.
52
A study was conducted by Hashimoto in which a manure storage pit beneath
caged layers was aerated, using compressed air forced through plastic pipes.
Air was released to the liquid manure through 0.32 cm (1/8 in.) holes at 30.5 cm
(1.0 ft) spacing along the bottom of the manure storage tank. He recorded
the effects upon odor and also the changes of various water quality parameters.
With respect to odor control, he found a strong correlation between the odor
offensiveness as rated by an odor panel and the ammonia concentration in the
room air. In one series of trials in which the tank was initially seeded with
established oxidation ditch liquor containing large numbers of nitrifying
47
-------
Table 13. AMMONIA PRODUCTION BY WHITE LEGHORN LAYER MANURE ADDED DAILY TO
A NINETEEN LITER (FIVE GALLON) CARBOY51
System
Diluted Undiluted
Manure feed rate (g/day)
Water feed rate (g/day)
Solids content in feed (percent)
Duration of trial (days)
Air flow rate (1/hr)
Ammonia added in manure (g/day)
Ammonia added during run (g)
Ammonia in carboy after trial (g)
Ammonia released to air (g)
Ammonia content of exit air
maximum (micrograms/1)
Odor:
Vapor dilution to threshold
Quality
75
225
25
50
28
0.37
18.5
48
3
i?n
1000-2500
o f f ens ive , s our
75
0
6
50
28
0.4
20
25
15
1000-2500
ammonia-like
Table 14. HYDROGEN SULFIDE PRODUCTION BY WHITE LEGHORN LAYER MANURE ADDED
DAILY TO A NINETEEN LITER (FIVE GALLON) CARBOY51
System
Diluted Undiluted
Manure feed rate (g/day)
Water feed rate (g/day)
Solids content of feed (percent)
Air flow rate (1/hr)
Sulfide added in manure (mg/day)
Sulfide added during trial (g)
Sulfide in carboy after trial (g)
H-S concentration in air,
maximum (micrograms/1)
Final pH in carboy
Percent sulfide present as H«S at
this pH
Comparative level of offensiveness
75
225
25
28
21.2
1.06
53.5
0.011
7.5
20
high
75
0
6
28
21.2
1.06
5.65
0.005
9.0
0.85
low
organisms, the ammonia content of the room air was held to less than 2 ppm
during the first 100 days of the trial. During this same period the odor
level within the room was judged to be very faint. In another trial in
which the tank was not seeded, the ammonia concentration of the air averaged
eight to 10 ppm during the first 60 days and the odor was judged definite
to strong throughout this period. Thus he concluded that nitrification
was helpful in odor control and that seeding the manure slurry was benefi-
cial in establishing nitrification during the early stages of the storage.
48
-------
CATTLE FEEDLOTS
53
Various attempts were described by Fosnaugh and Stephens to measure odor-
ous compounds in the vicinity of cattle feedlots. Although none of the
techniques proved entirely satisfactory, they tentatively concluded that
trimethylamine, propylamine, butylamine, and ethyl- or methyl-amine were
present in the odorous air near feedlots in concentrations above their
odor thresholds. The more promising techniques they described are sum-
marized in Table 15.
54
Work was reported by Bethea and Narayan concerning the identification of
odorous compounds evolved from beef cattle manure. In their initial ex-
ploratory work, a small volume of fresh manure was diluted with water and
placed in a flask and maintained under aerobic conditions. The gas re-
leased from this flask was then passed through a series of selective ab-
sorption flasks containing dilute hydrochloric acid, ether, sodium bicar-
bonate, sodium hydroxide or sulfuric acid. The material from the various
absorption flasks was then subjected to chromatographic analysis and the
following four classes of compounds were found: alcohols, amines, alde-
hydes, and esters. The fact that mercaptans and other organic sulfides
were not detected may be attributed to the aeration of the manure during
the absorption test. Following this work, gas samples were collected from
confinement chambers in which a steer was fed 10 kg (22 Ib) of a standard
roughage concentrate ration daily. The three manure management schemes
used were: (a) chamber thoroughly cleaned and washed every day; (b) ma-
nure shovelled out daily and no washing; and (c) no cleaning. Air from
the chambers was bubbled through four selective absorption traps and these
traps analyzed for odorous compounds extracted from the air. The data in
Table 16 summarize the results of these experiments. In addition to the
compounds listed in Table 16, carbon dioxide, carbon monoxide, ammonia
and hydrogen sulfide were reported as present under all three manure manage-
ment schemes.
In work to analyze amines in the air over a dairy manure sample, White
37
et al. first conducted a selective absorption of the amine compounds in
49
-------
Table 15. ODOROUS GAS DETECTION AND IDENTIFICATION SCHEMES EVALUATED BY FOSNAUGH AND STEPHENS
53
Scheme
Concentration
technique
Known compounds
tested
Comments
Paper chromatography
1.2 N HC1
amines
Possibly detected trimethylamine
near feedlot
Ul
o
Ammonia-amine absorp-
tion on silica gel
treated with ninhydrin
none
none
Ammonia and amines suggested at
concentration less than 1 ppm
Gas chromatography
electron capture
detector
0.1 N HC1
none
No results
Gas chromatography
flame ionization
detector
1.2 N HC1
methylamine
t rimethylamine
ethylamine
n-propylamine
n-butylamine
Presence of amines indicated
-------
Table 16. ODOROUS COMPOUNDS IDENTIFIED FROM THE ATMOSPHERE IN A BEEF
CATTLE CONFINEMENT CHAMBER UNDER THREE MANURE HANDLING PRO-
54
GRAMS
Clean, and wash daily Shovel out daily
No cleaning
Methanol
Acetaldehyde
Ethanol
iso-Butyraldehyde
Ethyl formate
Methanol
Acetaldehyde
Ethanol
2-Propanol
Skatole
Indole
Ethyl formate
iso-Butyl acetate
Methanol
Acetaldehyde
Ethanol
2-Propanol
Skatole
Indole
Ethyl formate
Propion aldehyde
Methyl acetate
iso-Propyl acetate
iso-Propyl propionate
iso-Butyl acetate
1.2 N HC1. After selective absorption, the solution was neutralized with
sodium hydroxide and heated to drive the amine compounds into a super-cooled
injection needle. The collected amines were analyzed with chromatographic
equipment. The column used was a 3.05 m (10 ft) stainless steel column
packed with five percent (by weight) tetrahydroxyethylethylenediamine (THEED)
and 15 percent (by weight) tetraethylenepentamine (TEP) on Chromosorb W.
A column temperature of 47 C was maintained for these tests. With this
approach, they were able to identify trimethylamine and ethylamine in the
headspace over both anaerobic and aerated dairy waste.
SWINE MANURE
In early work to identify gases involved in the odor associated with con-
finement swine buildings, Day, Hansen and Anderson used a U tube submerged
in a dry ice-acetone mixture to condense the compounds of interest. The
condensate was subjected to spectral analysis. Other qualitative techniques
were used to detect hydrogen sulfide and ammonia. They noted that the
51
-------
filter paper preceeding the cold trap was accumulating not only dust but
also a strong, objectionable odor characteristic of the swine unit.
From these efforts, they identified hydrogen sulfide, methane, carbon
dioxide, and ammonia as being present in the buildings.
Work reported by Merkel et al. utilized a variety of selective absorp-
tion techniques followed by chromatographic analyses to identify specific
compounds present in the atmosphere of a swine confinement building. Di-
lute hydrochloric acid was used to absorb ammonia and amines. A mercuric
chloride-mercuric cyanide solution was used to absorb sulfur containing
compounds. Propylene glycol, which has a high absorption for organic
alcohols, was used to isolate those compounds. Carbonyls were collected
by using an absorption solution of dichloro methane. Using this procedure
they were able to conclude that amines, amides, alcohols, sulfides, di-sul-
fides, carbonyls and mercaptans were contained in the atmosphere of the
swine confinement building in addition to the fixed gases: carbon dioxide,
methane, ammonia and hydrogen sulfide. The alcohols specifically identi-
fied were methanol, ethanol, N-propanol, iso-propanol, n-butanol, iso-bu-
tanol and iso-pentanol. Among the carbonyls identified were formaldehyde,
acetaldehyde, propionaldehyde, iso-butyraldehyde, heptaldehyde, valeralde-
hyde, octaldehyde and decaldehyde. Based upon physiological investigation
they concluded that the major constituents of the odor were the amine and
sulfide groups.
To check for the presence of carbonyl compounds in a swine building,
Hartung et al. used an absorption column consisting of glass beads, coated
with a layer of 2,4 dinitrophenylhydrazone. In making the absorption col-
umn, two grams of silica gell were stirred with two ml of the DNPH.
The powder was then slurried in carbonyl-free hexane and transferred to the
column. Carbonyl-free air was used to evaporate the hexane from the column
and then the column was transferred to the swine atmosphere of interest.
The air sample was pulled through the column by the use of a vacuum pump
and then the column was transferred to the laboratory for carbonyl recovery.
Carbonyl-free hexane was used to elute the DNPH derivitive of interest
52
-------
the column. The eluted material was evaporated to a small volume then
placed on thin-layer chromatography plates. Using this technique, the
presence of the following carbonyl compounds was shown: ethanal, pro-
panal, butanal, hexanal, acetone, 2-butanone and 3-pentanone. They con-
cluded that propanol, acetone, and 2-butanone probably contributed to the
overall odor through additive effects even though only ethanal was mea-
sured in concentrations exceeding its threshold odor concentration.
To detect the presence of amines in a swine building atmosphere, Miner
and Hazen pumped the air through a solution of five percent acetic acid
in water. The ammonia and amines were selectively absorbed from the air
while the acetic acid was stripped from the liquid. After a period of
aerations, the liquid was subjected to chromatographic analysis. Analy-
ses were conducted using a 4.6 m (15 ft), 0.32 cm (1/8-in.) diameter stain-
less steel column packed with Porapak Q. This work indicated the presence
of methylamine, ethylamine and triethylamine in the air inside a swine
building in which manure was being stored beneath partially slotted floor-
ing. Since all three of these compounds have low threshold odor levels,
they were judged to be contributing to the odor.
The concentration of various gases in the atmosphere of an enclosed swine
building was determined by Lebeda and Day. Air was analyzed under two
conditions: (a) when the unit was ventilated at a rate of 1.0 cu m per
minute (35 cu ft per minute) per animal and (b) when the forced ventilation
had been turned off for six hours. Results of these analyses are given in
Table 17. None of the gas concentrations measured reached levels considered
harmful to humans.
Table 17. GAS CONCENTRATIONS MEASURED IN AN ENCLOSED SWINE UNIT WHEN VENTI-
LATED AND WHEN VENTILATION HAD BEEN INTERRUPTED FOR SIX HOURS57
Concentration, ppm
Nonventilation for
Constituent Ventilated six hours
Ammonia 7.4 18.8
Carbon dioxide 656.0 4,286.0
Hydrogen sulfide 0.09 0.28
Sulfur dioxide 0.026
53
-------
MISCELLANEOUS MEASUREMENTS
The soil atmosphere beneath a cattle feedlot was compared to the atmosphere
beneath a cropped field by McCalla and Elliott?8 They used gas diffusion
bottles and then returned the collected samples to the laboratory for a
chromatographic analysis. A more reducing atmosphere was present beneath
the cattle feedlot as indicated by higher carbon dioxide and methane con-
centrations as well as lowered oxygen and nitrogen content.
A Burrell gas analyzer with absorption pipettes and oxidation heaters was
used by White and Taiganides to measure carbon dioxide, carbon monoxide,
oxygen and illuminants. A copper oxide heater was used to measure hydro-
gen and a catalytic heater was used for the paraffin hydrocarbons. An
Orsat gas analyzer was used to measure carbon dioxide, carbon monoxide,
and oxygen. These analyses were conducted on gas produced during the py-
rolysis of animal manures.
A modification of the chemical oxygen demand analysis as used in waste-
59
water studies was employed by Frus et^ a^. to measure organic gases in
a swine building atmosphere. The technique was sensitive to significant
changes in odor level and to rates of ventilation within the building.
Difficulties with the procedure were associated with reproducibility and
variable sensitivity to gases depending upon their solubilities and ease
of oxidation.
SUMMARY
The identification of specific gases responsible for livestock and poultry
manure odors has proven a difficult and tedious task. Identification of
the common and most abundant gases has not satisfactorily explained the
observed odors. The research findings indicate that the odorous gases are
primarily the end and intermediate products of anaerobic decomposition
which have sufficient volatility to escape from the liquid phase.
The primary tool for odorant identification has been gas liquid chrom-
atography. Thin layer chromatography and mass spectrescopy have received
54
-------
limited use. The major limitation in specific compound identification
has been the low concentrations at which the odorants are present. Many
of the compounds have perceptible odors at concentrations of less than
one part per million and less than the minimum detectable concentration
of the most sensitive detectors available on gas chromatographs. When
highly sensitive detectors have been employed, frequently it has been
found that other compounds, present in many times greater concentrations
but of less odor significance, tend to interfere with the analyses.
To overcome the problems of detecting these low concentrations, various
selective enrichment schemes have been utilized. The use of cold traps
in which the odorous gases were passed through a U-tube submerged in a
cold liquid, dry ice-acetone or liquid nitrogen has been helpful but
suffers from a lack of selectivity. Solid media covered with selective
absorbents have been successfully used as have general absorbents which
are brought into equilibrium with the odorous gas. Selective liquid ab-
sorbents, dilute acid for ammonia and amines, mercuric salt solutions for
sulfur-containing compounds, propylene glycol for alcohols and dichloro-
methane for carbonyls have been most commonly used and with general success,
An examination of the lists of compounds isolated from the air in contact
with anaerobically decomposing manure (Table 18) documents the existence
of a large number of compounds of potential importance in odorous air.
This large list also exemplifies the complexity of odor analysis. This
list further explains the variability in characteristics commonly attri-
buted to animal waste odors. Changes in feed rations, animal physiology
or manure handling may be expected to alter the quantitative make-up of
the volatile by-products of manure decomposition, thus, the exact nature
of the odor produced by a livestock operation.
55
-------
Table 18, COMPOUNDS IDENTIFIED IN THE AIR FROM THE ANAEROBIC DECOMPOSI-
TION OF LIVESTOCK AND POULTRY MANURE
Alcohols (1.8)
Methanol (1,8)
Ethanol (1,8)
2-Propanol (1,8)
n-Propanol (8)
n-Butanol (8)
iso-Butanol (8)
iso-Pentanol (8)
Acids (6)
Butyric (7,6)
Acetic (6)
Propionic (6)
iso<-Butyric (6)
iso'-Valeric
Amines (1.2.4.5)
Methylamine (4)
Ethylamine (2,4)
Trimethylamine (2)
Triethylamine (4)
Carbonyls (1,3.8)
Acetaldehyde (1,3,8)
Propionaldehyde (1,3,8)
iso-Butyraldehyde (8)
Hexanal (3)
Acetone (3)
3-Pentanone (3)
Formaldehyde (8)
Heptaldehyde (8)
Valeraldehyde (8)
Octaldehyde (8)
Decaldehyde (8)
Sulfides (2.6)
Dimethyl sulfide (2)
Diethyl sulfide (2)
Nitrogen heterocycles (6)
Indole (6,1)
Skatole (6,1)
Esters (1.2)
Ethyl formate (1)
Methyl acetate (1)
iso-Propyl ace-
tate (1)
iso-Butyl ace-
tate (1)
iso-Propyl pro-
pionate (1)
Propyl acetate (2)
n-Butyl acetate (2)
Fixed gases
Carbon dioxide
Methane
Ammonia
Hydrogen sulfide
Mercaptans (2,6)
Methylmercaptan (2)
Disulfides (6)
Note: Numbers in parentheses refer to the references below in which iden-
tification was reported.
1. R. M. Bethea and R. S. Narayan 1973. 54
6.
7.
8.
37
56
2. R. K. White, e£ al. 1971.
3. L. D. Hartung e£ al. 1971
4. J. R. Miner and T. E. Hazen 1969. 6
5. J. Fosnaugh and E. R. Stephens 1969.
35
53
W. E. Burnett 1969.
48
R. H. Deibel 1967.
J. A. Merkel 1969.
36
56
-------
SECTION VIII
MEASUREMENT OF SPECIFIC ODOROUS GAS CONCENTRATIONS
Although a large number of gases have been identified as being released
from animal manure during transport, storage, treatment and disposal,
only a limited number of these have been routinely measured as parameters
of odor intensity. It is the purpose of this section to summarize those
procedures in current use so they might be readily available to people
working in the area and to aid people utilizing air analyses to more
intelligently interpret the data.
AMMONIA
The most widely used method of analysis giving satisfactory results in-
volves selective ammonia absorption followed by color formation using
Nessler's reagent. Recommended absorbing solutions include two percent
boric acid in ammonia-free water and a diluted sulfuric acid solution
60
made by adding one ml concentrated sulfuric acid to 10 1 of water.
A measured quantity of absorbing solution is placed in an absorption
flask or impinger and contacted with a measured air volume. Using fresh
absorbing solution as a blank, the absorbed ammonia is measured by add-
ing Nessler's reagent. Color intensity is best measured at 425 my.
Directions for the preparation of Nessler's reagent are found in Stan-
dard Methods50 or it can be purchased commercially already prepared.
Results are most appropriately expressed as parts per million by volume
or micro grams per liter. This method was used by Burnett and Dondero
6
and by Miner and Hazen.
Another technique for estimating ammonia concentrations in air is based
on the equilibrium distribution of ammonia in water and in the surround-
ing atmosphere. At equilibrium, the partial pressure of ammonia in water
is equal to its partial pressure in the surrounding atmosphere. The
ammonia content of a distilled water containing ammonia can be estimated
from a pH measurement, knowing the temperature of the solution and the
57
-------
appropriate dissociation constants. Kowalki et_ &L. developed a rela-
tionship between ammonia content in water and its partial pressure. Thus,
by bringing a distilled water into equilibrium with an air sample contain-
ing ammonia, it is possible to estimate the ammonia concentration of the
air based upon the ammonia content of the water. The pH of the water can
be used as a measure of the equilibrium ammonia content. This general
47
approach was utilized by Koelliker and Miner in estimating the ammonia
loss from an anaerobic lagoon. Table 19 represents the calculated pH val-
ues of water in equilibrium with various concentrations of ammonia in air.
Table 19. CALCULATED pH VALUES OF DISTILLED WATER IN EQUILIBRIUM WITH
VARIOUS AMMONIA CONCENTRATIONS IN AIR AT 20° C
ppm vol.
1
5
10
50
100
500
P
g
1 x
5 x
5 x
5 x
= PL
-6
10 °
10
10 S
10 .
10,
io-4
pH of
water
9.5
9.9
10.0
10.4
10.5
10.9
6?
This general technique was utilized by Mourn, Seltzer and Goldhaft in
devising a quick method for estimating the ammonia content of air. In
their procedure, pH test paper is moistened with distilled water and con-
tacted with the air for 15 seconds. At that time, the pH is recorded and,
using the data from Table 20, the ammonia content is estimated. Special
packets for this purpose, consisting of pH paper, a calibration color card
which interprets color directly as ammonia content, and a bottle for carry-
ing distilled water, all in a single case, are marketed by Vineland Lab-
oratories, Vineland, New Jersey.
Table 20. AMMONIA CONCENTRATION (ppm) IN AIR BASED ON THE pH OF A TEST
PAPER AFTER 15 SECONDS OF CONTACT62
pH
6
7
8
9
10
11
NH« concentration
0
5
10
20
50
100+
58
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HYDROGEN SULFIDE
Modifications of the method for analyzing hydrogen sulfide concentra-
tions in wastewater as prescribed in Standard Methods have been widely
adopted for gas analysis. In essence, a measured volume of gas"is passed
through two absorption flasks in series, each containing 100 ml of 0.1 N
zinc acetate solution. Similarly, a cadmium hydroxide suspension can be
63
used for the absorption. The hydrogen sulfide reacts to form a zinc
or cadmium sulfide suspension. The sulfide content of the suspension may
be measured by a titration or a colorimetric procedure.
In the titration procedure, excess 0.025 N iodine solution is added to
each of the absorption flasks along with 2.5 ml of concentrated hydro-
chloric acid. The contents of the flasks are then combined and the ex-
cess iodine titrated with 0.025 N sodium thiosulfate. The quantity of
iodine utilized in oxidizing the sulfide ion is a measure of the sulfide
content of the air.
In the colorimetric procedure, a solution of acidified N, N-dimethyl-p-
phenylenediamine oxalate and one of ferric chloride are added to the zinc
sulfide suspension. Methylene blue will be formed in proportion to the
amount of sulfide present. The intensity of methylene blue color can be
estimated or measured using a spectrophotometer at 600 my. This proce-
dure is described for use in air pollution studies by Jacobs. Reagents
for this procedure are marketed by Hach Chemical Company of Ames, Iowa.
MERCAPTANS
The mercaptans or organic thiols have been identified as a group as being
important in animal waste odors. Thus far, they have not been routinely
measured by researchers dealing with livestock waste odors but have been
detected as being present in the odor given off from cattle feedlots
cc. "\~]
and listed by Merkel, Hazen and Miner and by White et^ aiU as being
present in the odors from anaerobic decomposing swine and dairy cattle
manures. A method for the quantitative measurement of the mercaptans has
59
-------
/• o
been published by the American Public Health Association. In principle,
the technique is to absorb the mercaptans by passing a known volume of air
through an aqueous solution of mercuric acetate-acetic acid. The collect-
ed mercaptans are subsequently determined by a spectrophotometric measure-
ment of the red complex produced by the reaction between mercaptans and a
strongly acid solution of N,N,-dimethy1-p-phenylenediamine ferric chloride.
The method determines total mercaptans and does not differentiate among in-
dividual mercaptans although it is reportedly more sensitive for the lower
molecular weight alkane thiols.
The technique is designed to provide a measurement of mercaptans in the
3
range below 200 yg/1 (102 parts/billion). For concentrations above
100 parts/billion, the sampling period can be reduced or the liquid vol-
ume increased either before or after aspirating. The minimum detectable
amount of ethyl me reap tan is 0.04 jag/ml in a final liquid volume of 25 ml.
When sampling air at the maximum recommended rate of one 1/min for two
hours, the minimum det<
ppb methyl mercaptan).
3
hours, the minimum detectable mercaptan concentration is 3.9 ug/m (2.0
The N,N-dimethyl-p-phenylenediamine reaction is also suitable for the de-
termination of other sulfur-containing compounds including hydrogen
sulfide and dimethyl disulfide. The potential for interference from these
latter compounds is especially important since all these compounds com-
monly coexist in odorous air. By appropriate selection of the color for-
mation conditions, the interference from hydrogen sulfide and dimethyl
disulfide can be minimized.
The procedure involves collection of the sample by passing air through
15 ml of an absorbing solution of 50 g of mercuric acetate and 25 ml of
an absorbing solution of 50 g of mercuric acetate and 25 ml of glacial
acetic acid diluted to one 1. The sample, after exposure to a known
volume of air, is removed from the aspirator, diluted to 25 ml and the
color-forming agent added. The color-forming reagent is a mixture of a
solution of N,N,-dimethyl-p-phenylenediamine hydrochloride and a solution
of ferric chloride hexahydrate. Directions for the mixing and formulation
of this color-forming reagent are contained in the reference. A standard
60
-------
mercaptan solution can be made by weighing out an appropriate quantity
of lead mercaptide and diluting to an appropriate concentration.
VOLATILE ORGANIC ACIDS
Volatile organic acids are produced as an intermediate breakdown product
of carbohydrates. In a well-operating anaerobic digestion system, the
volatile organic acids are decomposed as produced and, ideally, never
reach such a high concentration as to reduce the overall pH of the solu-
tion. Traditionally, when anaerobic digestion systems have failed,
an excess of volatile acids has been noted to accunulate, thus monitor-
ing of the organic acid content has been one method for controlling
anaerobic digestion. Associated with the accumulation of organic acids
has been a sharp change in the odor characteristics of digesting materials.
For this reason, it is not surprising that volatile acids are produced
during the anaerobic decomposition of animal manures and that they are
related to the observed odor characteristics.
There are two methods for the analysis of organic volatile acids:
(a) the distillation technique, and (b) the chromatographic technique.
The basic philosophy in the distillation technique was summarized by
Sawyer.6^ In this procedure, a liquid sample is acidified with sulfuric
acid to adjust pH to less than 1.0. At this pH, the volatile acids are
in the nonionized form and exert their maximum vapor pressure. They may
be distilled from the solution by either direct heating or by steam in-
jection. The direct heating is more rapid but more subject to error than
steam injection distillation. The technique involves distillation of the
volatile acids and their collection followed by titration with a dilute
standard base. Recovery of volatile acid is consistently less than
100 percent using either of these procedures. Thus, it is necessary to
determine the efficiency of the particular apparatus being used and to
include this efficiency in calculating the final results.
In the partition chromatography technique, a solid absorbant - in this case
silicic acid- is placed in a column and a sample of the liquid containing
61
-------
the volatile acids is placed on top of the column. Once the acidified
sample is placed on the silicic acid, a mobile phase is passed through
the column. The mobile phase is a mixture of chloroform and butanol.
This mixture selectively carries with it the nonionized volatile acids
which are more soluble in this mixture than in the stationary water phase.
The sulfuric acid and other ionized salts, however, are more soluble in
the water and so are left behind. The extracted volatile acids are then
measured by titration with sodium hydroxide to the phenolphthaline end-
point as is done in the distillation procedure.
Both of the above techniques can be modified for the measurement of vola-
tile acids in air. The usual method is to collect a sample by bubbling
a measured volume of air through a dilute alkaline solution for the absorp-
tion of volatile acids. Once the organic acids from a measured volume of
air have been extracted, the absorbing solution is acidified with sulfuric
acid and the volatile acid concentration determined by either distillation
or by partition chromatography.
62
-------
SECTION IX
QUANTITATIVE MEASUREMENT OF ODORS
The technological difficulties of quantitative odor measurement are for-
midable. As explored earlier, odor is essentially a subjective response
to the mixture of chemical compounds present in the air. This response
is a function not only of the chemical make-up of the air but also is
dependent upon the psychological disposition of the observer as well.
Evaluation of an odor is thus a complex physiological and psychological
process and it is little wonder that techniques for quantitative measure-
ment of odors have been fraught with difficulty. Two separate aspects
of odor can be identified: strength or intensity and quality.
ODOR STRENGTH
Odor strength or intensity is the more direct and easily measured of the
two aspects. The current concept is that each odor source may be diluted
sufficiently with odor-free air to be indistinguishable from odor-free
air by the human nose. That concentration which is barely distinguishable
from odor-free air is termed the threshold odor. The strength of an
actual odor can be defined in terms of the number of dilutions with odor-
free air required to reduce the odor to the threshold concentration,
Similar to the air dilution technique, a liquid dilution technique can be
used. A liquid which has an odor can be diluted with odor-free water un-
til the liquid odor is no longer distinguishable from that of odor-free
water.50 Both the air dilution and liquid dilution techniques have been
used in evaluating animal waste odors,
In the liquid dilution technique, a sample of the odorous material is mix-
ed with odor-free water. Generally, the diluted sample along with some
odor-free samples are then offered to a panel of observers. General tech-
nique is to make up a series of five bottles to offer to the panel, two
containing a dilution of the odorous material and the other three
63
-------
containing odor-free water. Panel members are asked to mark on their
score sheet those bottles which contain the odorous material. By making
a series of dilutions and offering them to the odor panel for evaluation,
minimum detectable concentration of the material can be determined. By
making the liquid dilutions successively greater by a factor of two, those
data can be used to determine an odor intensity index (Oil). In other
words, if the threshold odor was determined to be at a dilution of 15 parts
odor-free water to one part of odorous solution, the odor intensity index
would be four. The other means of expressing this information would be as
the threshold odor number (TON). Threshold odor number is equal to two
28
raised to the odor intensity power. Using this approach, Sobel measured
the odor intensity index and threshold odor number of a series of diluted
chicken manure samples stored over a period of six weeks. The odor inten-
sity of undiluted manure remained essentially constant at nine or a threshold
odor number of 512. For manure diluted three to one, he found the initial
odor intensity index to be equal to nine but after the first week the odor
of this material increased so that at the end of three weeks he measured
an odor intensity index of 15 or a threshold odor number of 32,768.
The vapor dilution technique involves actual dilution of odorous air with
28
odor-free air. Using this technique, Sobel measured the dilution which
is the ratio of the volume of odorous air divided by the volume of odor-
free dilution air which is offered to the observer. The dilution as used
in this technique is essentially equivalent to the threshold odor number
of liquid measurements. Using this approach, he again demonstrated that
the odor of diluted manure was considerably more intense than the odor
of undiluted manure. He also concluded that the quality of the odor from
the diluted manure was considerably more offensive to the panel than the
ammonia-like odor from undiluted manure.
The odor of stored dairy cow manure was studied by Earth, Hill and Polkowski.
By using various aeration rates, they were able to produce a variety of odor
intensity indexes as well as variable concentrations of volatile acids,
ammonia, and hydrogen sulfide. Their results are summarized in Table 21.
From these studies correlations were developed relating the concentrations
64
-------
of the three odorants in the liquid manure to the observed odor inten-
sity index. Those relationships are as follows:
Oil = 3.04 C°'2° R = 0.92 (18)
Oil = 0.64 C^ °*46 R = 0.71 (19)
Oil = 11.5 0. c°*°9 R = 0.80 (20)
-H2S
Oil = 2.70 (CVOA°'21 CR s~°'01) R = 0.72 (21)
Oil = 10,88 (CVOA°-28 Cm -°'°4) R = 0.94 (22)
011 - 10'2
-------
of people to accurately describe odors. One device on the market for the
estimation of odor intensity is the scentometer. The scentometer is
essentially a rectangular, plastic box containing two air inlets (one for
each activated charcoal bed) and four odorous air inlets; 0.159, 0.318,
0.635 and 1.27 cm (1/16, 1/8, 1/4 and 1/2 in.) in diameter.67 The odorous
inlets are directly connected with a mixing chamber and the nasal outlets.
See Figure 6.
Table 21. ODOR INTENSITY INDEX AND ODOROUS COMPONENTS IN THE SUPERNATANT
OF LIQUID DAIRY MANURE RECEIVING VARIOUS RATES OF AERATION66
Aeration Aeration
Rate, Depth
Unit cc/min cm Week
2 400 36 1
2
3
4
5
3 300 43 1
2
3
4
5
60 01
2
3
4
5
7 300 20 1
2
3
4
5
Odor
Inten-
sity
Index
10.0
8.5
11.0
12.0
13.0
9.0
8.0
10.0
11.5
12.0
14.5
16.5
15.5
14.0
16.0
8.5
9.8
10.0
11.0
12.0
Odorous
V.O.A. ,
mg/1
309
512
481
724
1182
275
565
588
678
900
1566
3290
3950
4940
6900
238
634
733
988
3740
components in liquid
NH3-N
mg/1
340
448
473
632
785
341
484
547
512
840
510
660
843
1007
1444
396
476
570
735
1108
H2S-S* PH
mg/1
.30 8.21
a .51
a 8.63
.20 8.56
b 8.57
.20 8.22
a 8.61
a 8.65
.10 8.63
b 8.55
6.6 7.24
13.8 7.15
11.7 7.14
23.5 7.08
b 6.69
.30 8.33
.30 8.47
1.50 8.50
.90 8.47
b 8.24
*Definition of symbols: a. Insufficient component present to give positive
result.
b. No determination made.
In field operations, the observer takes the scentometer where the odor
intensity is to be measured. He places the device to his nostrils, cover-
ing the odorous air inlet ports with his fingertips and breathes through
the instrument to adjust his sense of smell to odor-free air. The concept
66
-------
FIG. 6 SCENTOMETER
67
ODOROUS AIR
INLET PORTS
SNIFFING
PORTS
SCREEN ON BOTH
SIDE OF CHARCOAL
FILTER
-------
is that any air entering his nostrils under these conditions will have
passed through the activated charcoal beds and be odor free. Once his
sense of smell has become acclimated to odor-free air and his sense of
smell rested to the point of maximum sensitivity, the ports are opened in
successively larger diameters beginning with the smallest port. He con-
tinues in this manner until an odor is first detected coming through the
device. The design is such that odorous air is mixed with the filtered
air in definite proportions so that recording the port or ports that
were opened at the time he first detected an odor provides a measure of
the dilutions required to reach the odor threshold. Table 22 provides
a correlation between the ports which are open and the calculated dilu-
tion which is entering the nostrils of the observer. By having a combina-
tion of ports open, it is possible to estimate odor dilutions through
thresholds ranging from 1.47 to 170. Measurements made with more than one
port open, however, are subject to question because of the frequent
Table 22. DILUTION TO THRESHOLD VALUES WITH VARIOUS PORTS OPEN ON A
SCENTOMETER WHEN AN ODOR IS BARELY DETECTABLE
*
Odorous Air Inlets
Dilutions
to Threshold
1.47
1.49
1.55
1.88
2.00
5.55
5.75
6.75
7.00
27.00
31.00
170.00
1.27 cm
(1/2 in.)
0
0
0
X
0
X
X
0
X
X
X
X
0.635 cm
(1/4 in.)
0
0
0
0
X
0
0
X
0
X
X
X
0.318 cm
(1/8 in.)
0
0
X
X
X
0
0
0
X
0
0
X
0.159 cm
(1/16 in.)
0
X
X
0
X
0
X
X
X
0
X
0
*Definition of symbols: x indicates port is covered
0 indicates port is open
68
-------
inability of the observer to detect small differences in odor inten-
sity.
£ O
In discussing the scentometer, Huey &t_ a^. stated that their experience
had shown that odors above seven dilutions to threshold would probably
cause complaints while those measuring 31 dilutions to threshold could
be described as a serious nuisance if they persist for a considerable
69
length of time. The scentometer was described in a paper by Rowe in
which he indicated that it required about ten times the perceptible odor
threshold to give a definite sensation of odor and another tenfold in-
crease of odor to be considered a strong odor.
The scentometer has received rather widespread application in animal waste
odor evaluation. In spite of its application, however, there are sev-
eral basic limitations to this approach. Being a personal observation,
the sensitivity of the observer is highly important in determining the
values achieved with the instrument. Although sniffing through the
scentometer with the odorous air ports closed is designed to restore
normal sensitivity to the observer, complete restoration of the smell
sensitivity may not occur rapidly enough to obtain meaningful results.
The charcoal bed can become saturated and not give a complete odor re-
moval from the air breathed when all the ports are closed. Since there
is no indicator to show the carbon is saturated, misleading results may
be obtained under these conditions. Intermittent odors which are common
in animal waste, particularly when observations are made some distance
from the odorous source, present additional difficulties and require use
of the scentometer over a considerable period to get representative data.
In spite of these limitations, however, the scentometer is a useful de-
vice and is being used by some regulatory agencies.
ODOR QUALITY
In contrast to odor strength, which can be quantitatively evaluated, there
is no straight forward technique to quantify odor quality. Most frequently,
odor quality is described by comparison to some common odorant with which
the reader or listener is familiar or to a sensation with which he is
69
-------
OT
familiar. For example, White et_ a^. used the following terms to describe
the odorous components of dairy waste: foul, sweetish, acetate, nutlike,
pungent, and musty. In describing the odor of the various fractions of
35
poultry manure odor, Burnett used the following words: rotten egg, rot-
ten cabbage, onion-like, putrid, butter-like and garlic.
An alternative method to evaluate odor quality was used by Sobel. He ask-
ed a panel of odor evaluators to select a number from one to 10 indicating
the degree of offensiveness of the samples. A nonoffensive odor was mark-
ed as zero, a very strong offensive odor was ranked as 10, a definite offen-
sive odor was six and a faint offensive odor was four. He also asked panel
members to select suitable descriptors from the following list to describe
the odor of the sample: mold, musty, fish, stagnant water, sulfide, rot-
ten egg, petroleum, earth, yeast, ammonia, grain, feed, sour, fermented
and cabbage. Using this approach, he was successful in differentiating
the offensiveness of an odor and the odor strength.
70
-------
SECTION X
FECAL ODOR AS AFFECTED BY FEED ADDITIVES
The effects of various feed additives on swine fecal odor were studied in
three feeding trials at Texas Tech University by Ingram et al. In each
trial, pigs were assigned to five treatments, three replications or pens
per treatment with four or five pigs per replicate. Fecal samples were
composited from any three of the pigs in each replication and immediately
evaluated by olfactory panels in trials one and two and by panels and column
chromatographic analyses in trial three. Gas-liquid separation was a quali-
tative measurement of primarily the organic amines, skatole and indole.
Composition of the basal diet is shown in Table 23.
72
Table 23. COMPOSITION OF BASAL DIET FOR ANIMALS ON FECAL ODOR STUDY
Ingredient Percent, air-dry
Grain sorghum 66.0
Soybean meal (44%) 30.0
Salt 0.5
Defuor. phosphate 1.5
CaC03 0.5
Premix (vitamin-mineral) 1.5
Treatments for trial one and the results are shown in Table 24. The feeding
period was 14 days duration, using four-week-old-pigs. The treatments were
basal; dry Lactobacillus acidophilus in a wheat bran carrier and mixed into
two feedings per day of five g each; lyophilized yeast culture at five per-
cent of the diet, replacing grain sorghum; L_. acidophilus cultured in whole
milk with an average of 2.9 x 10 viable cells per ml and mixed into the
feed twice daily at the rate of 175 ml each time; and last, activated char-
coal at five percent of the diet, replacing grain sorghum. Two panels of 11
participants and 31 participants scored the fecal samples for volatile
matter on a scale of one through 10, one being not objectionable through 10,
extremely objectionable.
71
-------
Table 24. TREATMENTS AND RESULTS - TRIAL 1. TEXAS TECH UNIVERSITY
SWINE FECAL ODOR STUDY72
Treatment Odor score
Basal 7.6
Dry lacto (10 g) 7.5
Yeast (5%) 7.4
Wet lacto (350 ml) 7.2
Charcoal (5%) 6.7
Orthogonal mean comparisons resulted in a significant difference between
the basal and dry lacto treatments versus five percent charcoal in re-
duction of volatile matter.
Table 25 shows treatments and results for trial two. The feeding period
was 10 days in length and the pigs from trial one were rerandomized for
the second trial. Olfactory observations were made by two panels of 23
and 27 participants. There were no significant differences among the treat-
ment means.
Table 25. TREATMENTS AND RESULTS -TRIAL 2. TEXAS TECH UNIVERSITY SWINE
FECAL ODOR STUDY
Treatment Odor score
Basal 6.5
Sagebrush (5%) 6.3
Wet lacto (300 ml) 6.3
Whole milk (300 ml) 6.2
Charcoal + Wet lacto 5.9
Table 26 summarizes treatments and olfactory panel results for trial three.
Three panels of 60 participants each evaluated fecal samples for trial three.
The feeding period lasted 21 days and used four-week-old pigs.
72
-------
Table 26. TREATMENTS AND RESULTS - TRIAL 3. TEXAS TECH UNIVERSITY SWINE
FECAL ODOR STUDY72
Treatment Odor score
Basal 6.5
Wet lacto (300 ml) 6.5
Charcoal (2%) 6.8
Yeast (2%) 6.5
Dry lacto (10 g) 6.7
No significant mean differences were detected by the olfactory panel. Fecal
samples in trial three also were used for some gas chromatographic analy-
ses. A sample of air from just above the feces was used.
By the end of the second week, as shown in Table 27, chroma tographic analy-
ses indicated a marked reduction in volatile matter of feces for the yeast
and dry lacto treatments.
Table 27. CHROMATOGRAPHIC RESULTS AFTER 2 WEEKS - TRIAL 3: TEXAS TECH
UNIVERSITY SWINE FECAL ODOR STUDY 2
Treatment
Basal
Wet lacto (300 ml)
Charcoal (2%)
Yeast (2%)
Dry lacto (10 g)
Peak Height Ratio
1.00
0.83
0.95
0.28
0.07
% Reduction
—
17
5
72
93
The peak-height ratio was used as a comparison between each treatment and
the basal diet - involving measurement of the height of each peak on the
chromatogram and then using peak height as the denominator. The percent
reduction indicates the decrease in volatile matter for each dietary treat-
ment as compared to the basal diet.
73
-------
Table 28 indicates the percent reduction in volatile matter of the feces
from pigs in trial 3 after 21 days of feeding.
Table 28. CHROMATOGRAPHIC RESULTS AFTER 3 WEEKS - TRIAL 3; TEXAS TECH
72
UNIVERSITY SWINE FECAL ODOR STUDY
Treatment
Basal
Wet lacto (300 ml)
Charcoal (2%)
Yeast (2%)
Dry lacto (10 g)
Peak height ratio
1.00
0.61
0.72
0.07
0.003
% Reduction
—
39
28
93
99
Results indicate a significant reduction in volatile matter between the
basal treatment versus the yeast and dry lacto treatments. The volatile
72
matter detected was primarily skatole and indole.
In summary, these data indicate that a lyophilyzed yeast culture and a
commercial preparation of Lactobacillus acidophilus reduced the skatole
and indole content of feces of young pigs, but that the changes in vola-
tile matter content were not detected by olfactory panelists.
73
Based upon limited feeding trials at Colorado State University, sagebrush,
as a feed additive, was reportedly effective in reducing feedlot odor.
The effectiveness was attributed to the volatile oils being carried through
to the manure.
74
-------
CHEMICAL TREATMENT OF MANURE TO CONTROL ODORS
Several investigators have sought a procedure whereby some relatively
inexpensive chemical could be added to manure to achieve odor control.
One technique has been to add a chemical or mixture of chemicals which
will halt anaerobic decomposition. A second approach, to gain temporary
odor control, is to oxidize the odorous compounds present in a slurry.
Although they will be replaced with continued decomposition, this may al-
low time for the manure to be applied to cropland or otherwise moved so
that odors are not critical.
CHLORINE AND LIME
74
Day evaluated chlorine and lime as possible means to deodorize liquid
hog manure. In these tests, the chemicals were added to manure storage
tanks as the manure accumulated. It was determined that the daily chlorine
demand of hog manure was 50 g per 50 kg (0.1 Ib per 100 Ib) pig. When a
pit was treated at this rate, odor was eliminated and when the solids were
dewatered on a sand bed, they, too, were odorless. This amount of chlorine
was costly (63 cents per hog/month), however, and the method was not pur-
sued. In a similar study, lime was added to the manure to raise the pH to
11. Whenever the pH dropped to nine, more lime was added. The lime treat-
ment was also effective in eliminating odors by inactivating anaerobic bac-
teria. The daily lime requirement was reported as 80 g per 50 kg (0.16 Ib
per 100 Ib) pig. The lime treatment, although less expensive than chlorine,
was estimated as 10 cents per hog per month and increased the quantity of
solids to be handled.
Hydrated lime, added to manure in amounts between five and 20 percent, was
found to effectively deodorize poultry manure and to materially reduce the
nitrogen loss upon storage, according to a study by Yushok and Bear.
They suggested that since most soil would benefit by additional lime, the
cost of the lime required for deodorization could be charged against the soil
on which the manure was to be applied and not be a direct cost to odor control,
75
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The addition of sodium hydroxide to liquid poultry manure at a concentra-
tion of 0.9 percent was effective in preventing the development of objec-
tionable odors according to Benham. This treatment also resulted in a
reduction in the number of total aerobic bacteria and coliforms. The
application of the equivalent of 23 cu m (6,000 gal.) of poultry manure
containing this concentration of sodium hydroxide/acre of grassland was
not found to produce harmful effects on the grasses studied. The cost per
bird per month was estimated to be in the range of one to two cents. Thus,
it would cost $3,000 to $6,000 annually for a 25,000 layer operation to use
sodium hydroxide for odor control according to this study.
POTASSIUM PEBMANGANATE
Potassium permanganate (KMnO,) is a powerful oxidizing agent, in part be-
cause of its ability to undergo several different reaction paths. Perman-
ganate (MnO^ ) solutions are most effective as oxidizing agents (and,
therefore, in odor control) in acid solution, next in alkaline solution,
and least effective in neutral solution.
Three different oxidation reactions can take place, depending on the pH
of the solution:
In strong acid (pH < 2): MaO ~ + 8H+ 4- 5e~ -*• Mh*"4" + 4H20
In "more neutral solutions"
(pH 3-11) Mn04~ + 4H + 3e~ + Mn02 + 2H.O
In strongly alkaline solutions
(pH 11) ^in°et~ + e~ -> Mn04~
The most effective reaction, in a practical sense, is the second of the
above because the solutions are essentially noncorrosive. For all three
reactions, the reaction rate will increase with increasing temperature,
with increasing KMhO, concentration, and with increasing concentration of
oxidizable impurities. Also, the rate of reaction increases as the pH
varies from neutral in either direction.
76
-------
Potassium permanganate has been suggested for odor control around livestock
production facilities since 1964 when its use was reported by Faith. The
oxidizing capabilities of potassium permanganate when used in gas-scrubbing
78
devices were documented by Posselt and Reidies. In their studies, air
containing various odorants was passed through a pair of gas-washing bottles
in parallel. One gas-washing bottle contained a one percent solution of
potassium permanganate at a pH of 8.5; the other bottle contained distilled
water at a similar pH. Under these conditions, they compared the threshold
odor numbers of the effluents from the two bottles when various odorous or-
ganic compounds were being passed through the solutions. They evaluated the
use of potassium permanganate for the oxidation of various mercaptans, other
sulfur-containing compounds, amines, phenols and other organic odorants. In
each case they found significant reduction in the threshold odor number was
achieved by passing the gases through potassium permanganate compared to pass-
ing them through distilled water. Potassium permanganate is being marketed
by Carus Chemical company for use in odor control applications (See Appendix A
HYDROGEN PEROXIDE
The use of hydrogen peroxide has been proposed for various waste treatment
applications. Hydrogen peroxide (H_02) is commercially available as an
aqueous solution ranging from three percent for use as a disinfectant in
first aid up to 98 percent solutions. Its primary application is as an
oxidizing agent. Hydrogen peroxide decomposes to form water, molecular
oxygen, and an accompanying release of heat. Strong solutions, greater than
eight percent H-0_, are considered corrosive and must be handled in special-
ly selected materials,
Dairy manure
The use of hydrogen peroxide for the treatment of dairy cow manure was des-
79
cribed in a report by Hollenbach. In the first trial, 19 1 (5.0 gal.)
of 50 percent hydrogen peroxide were diluted and pumped at the rate of 2 1
(1/2 gal.) per minute into liquid manure tanks while the circulating pump
was used to provide mixing and circulation of the entire 89 cu m (24,000 gal.)
of manure in the system. Sufficient hydrogen peroxide was added to provide
a total concentration of 100 ppm in the mass. Their notes were as follows:
77
-------
prior to agitation and hydrogen peroxide addition, a pleasant silage or
animal type odor emanated from the vent and no hydrogen sulfide was de-
tected. Immediately upon agitation the sulfide concentration rose to
150 ppm and a strong sulfide odor was evident. Within 30 minutes, when
about half the hydrogen peroxide had been added, the sulfide concentra-
tion in the air dropped markedly and most of the odor had disappeared.
After one hour, when the full 100 ppm of hydrogen peroxide had been
added, no sulfide was detected and only a moderate ammonia odor remained.
When the agitation was discontinued for 18 hours and then resumed, the
hydrogen sulfide level and the gases were at the initial level before
the hydrogen peroxide addition. Thus, the hydrogen peroxide was, in their
view, a temporary but effective odor control technique under these conditions.
In a second trial, Hollenbach 9 added hydrogen peroxide as in the earlier
trial but immediately thereafter added a second similar quantity. He
found the additional hydrogen peroxide resulted in a further decrease in
the odor of the manure storage pits. Sixteen hours later, the sulfide
concentration had risen and was similar to that prior to treatment. Some
foaming difficulties were also reported during the second trial when the
larger peroxide additions were made. Hollenbach felt this foaming could
be prevented by adding a less concentrated peroxide solution. At the
100 ppm concentration used in the test about 6.0 1 (1.7 gal.) of 50 percent
hydrogen peroxide at a cost of about $3.90 would be required to eliminate
the sulfide type odors from a 37.8 cu m (10,000 gal.) manure storage tank.
In a study to test the effectiveness of hydrogen peroxide in treating
80
dairy cattle manure odors, O'Neill used hydrogen peroxide at concentra-
tions of 10 and 15 percent, adding sufficient hydrogen peroxide to pro-
vide 50 to 220 ppm. When hydrogen peroxide was added at 50 ppm, the
odor improvement was only limited. The sulfurous odors were removed but
strong animal and ammoniacal odors were apparent. With the 100 ppm
treatment, the strong animal odor was replaced by a strong silage odor
with vestiges of ammonia. Using 125 ppm, only a silage odor was evidenced.
Sulfides were determined at levels greater than five ppm in the manure
slurry before treatment but were reduced to zero by the hydrogen peroxide
78
-------
treatments at levels greater than 100 ppm. No foaming problems were en-
countered during these evaluations.
Swine manure
The use of hydrogen peroxide for the control of swine manure odors was des-
80
cribed in a report by O'Neil. In this study, pig manure slurry was treat-
ed with 10 percent hydrogen peroxide at levels of 115 and 275 ppm. The
hydrogen peroxide was fed into the open end of the discharge pipe as the
manure was pumped from a holding pit into a 5.3 cu m (1,400 gal.) liquid
manure tank. Hydrogen sulfide levels were reduced to zero in the gas
over the manure slurry under both test conditions. The investigator, how-
ever, thought that superior odor control was obtained using the 115 ppm
dosage. The reason for this increased effectiveness was judged to be
primarily because of the effective mixing that took place in that trial.
Atmospheric hydrogen sulfide was at a level of 10 ppm for the holding tank
but was reduced to zero in the tank spreader after treatment.
Poultry manure
81
Field trials were conducted by Kibbel, Raleigh and Shepherd at a large
poultry farm that regularly received complaints from neighbors about the
extremely foul and unpleasant odor when chicken manure slurry was spread
on the fields. Sufficient hydrogen peroxide to attain levels of 100,
150 and 175 ppm based on total slurry weight was added to the discharge
side of a pump used to transfer a five percent to 10 percent solids slur-
ry from the collection pit under the birds to a 5.3 cu m (1,400 gal.)
tank truck equipped to field spread the manure promptly for its plant
nutrient values. An area 3 m (10 ft) wide and 400 m (0.25 mile) in
length was used for manure application from each level of hydrogen per-
oxide treatment. Each test strip was separated from the adjacent test
zones by 30 m (100 ft). The farm manager and two Extension Service repre-
sentatives from Pennsylvania State University determined the overall qual-
ity and type of odor by sense of smell. Hydrogen sulfide specifically was
determined quantitatively with a Hach test apparatus. Additional checks
were made 18 hours later to determine the efficiency and persistence of
the treatments.
79
-------
All three hydrogen peroxide levels of 100, 150 and 175 ppm virtually
eliminated the presence of hydrogen sulfide and reduced the odor of the
chicken manure significantly. No differentiation could be made among
the manures treated with the several hydrogen peroxide levels. The offen-
sive chicken manure odor remained significantly reduced in the test plots
compared to the control (non-treated) plots on the second and third day
after application.
PARAFORMALDEHYDE
The use of flaked paraformaldehyde for the treatment of animal waste to
control odors was studied by Seltzer, Mourn and Goldhaft. Paraformalde-
hyde is a mixture of polyoxymethylene glycols containing 90-99 percent
polymerized formaldehyde and is available as powder, granules or flakes.
Its chemical formula is HOH^O-GH^-O^OH. It is very slowly soluble
in cold water.
Paraformaldehyde liberates formaldehyde gas as it decomposes. The flake
form liberates the gas most slowly of the various available forms. The
loss rate of paraformaldehyde is affected by temperature as indicated in
Table 29. The rate of paraformaldehyde decomposition is also increased
Table 29. PERCENT WEIGHT LOSS OF FLAKE PARAFORMALDEHYDE WHEN EXPOSED TO
82
AMMONIA-FREE AIR AT VARIOUS TEMPERATURES
Time
1 day
2 days
3 days
4 days
1 week
2 weeks
3 weeks
4 weeks
5 weeks
6 weeks
5° C
0.09
1.2
1.8
2.2
2.7
3.0
22° C
1.3
2.8
4.6
6.7
13.3
22.2
28.9
31.9
34.0
37.8
38°C
3.1
6.5
10.2
13.5
26.2
34.5
39.8
42.8
46.0
48.8
80
-------
by the presence of ammonia as is indicated in Table 30. The reaction of
formaldehyde with ammonia gas occurs as follows:
6 CH_0 + 4 NH. -> C.H..N. + 6 H.O (24)
/ j D \.L 4 {.
Table 30. PERCENT WEIGHT LOSS OF FLAKE PARAFORMALDEHYDE IN PRESENCE OF
Q r\
AMMONIA GAS FROM CHICKEN MANURE AT 22 C
Days
on test
1
2
3
4
7
0,5 g para-
formaldehyde
over 100 g
manure
13.1
37.1
48.8
77.1
Residue iden-
tified as hex-
amethylene
tetramine
1 g para-
formaldehyde
over 100 g
manure
5.2
19.7
33.7
38.3
58.1
'3 g para-
formaldehyde
over 100 g
manure
0.7
5.9
15.1
21.2
27.1
1 g para-
formaldehyde
over no ma-
nure
3.1
5.4
6.0
8.9
At ordinary temperatures this reaction is rapid and proceeds to completion.
The end product of the reaction, hexamethylene tetramine, is a white, pow-
dery, odorless material.
To test the effectiveness of paraformaldehyde in controlling poultry ma-
QO
nure odor, Setlzer ejt al. prepared six 3.8 1 (1.0 gal.) plastic bottles by
adding 100 grams of feces to each. Ten ml of water also were added to
each bottle to provide adequate moisture. Paraformaldehyde flakes were
added to the bottles in the amounts of 0.5-7-.0 g. The pH of the air over
the manure was measured as an indication of the ammonia content. Results
of this experiment are shown in Table 31.
After 12 days of this experiment a 1.0 g manure sample was removed from
each of the test bottles and subjected to bacterial counting on brain heart
infusion agar. Plates were incubated at 37° C for four days and the counts
shown in Table 32 were obtained. As part of this test, the manure was also
81
-------
Table 31. AMMONIA CONTENT (PPM) OF HEADSPACE GAS OVER 100 GRAMS OF
CHICKEN MANURE TREATED WITH VARIOUS LEVELS OF PARAFORMALDEHYDE
82
Days on test
1
2
5
7
9
14
21
28
0
100
100
100
100
100
100
100
Quantity
0.5
0
1
10
50
100
100
100
100
of paraformaldehyde added
1
0
0
1
10
100
100
100
100
3
0
0
0
0
0
0
0
0
5
0
0
0
0
0
0
0
0
> 8
7
0
0
0
0
0
0
0
0
Table 32. BACTERIAL COUNTS OF MANURE SAMPLES ON BRAIN HEART INFUSION AGAR
AFTER 11 DAYS OF EXPOSURE TO VARIOUS QUANTITIES OF PARAFORMALDE-
HYDE82
Quantity of paraformaldehyde added
per 100 g manure, g
Number of organisms per g
of manure
0
1
3
7
2.2 x 10'
1.64 x 10
1 x 10:
0
8
analyzed for nitrogen concentration. It was found that the paraformalde-
hyde had been effective in reducing nitrogen loss. The Kjeldahl nitrogen
concentration in the untreated samples was 1.39 percent. That in the
bottle containing three percent paraformaldehyde contained 1.75 percent.
Paraformaldehyde, when used as a manure additive, was indicated by these
tests to be effective in reducing the evolution of both ammonia and
hydrogen sulfide. In addition, it tended to reduce the number of viable
bacteria within the sample. Among the limitations of paraformaldehyde
is its toxicity to animals if they ingest more than the toxic dose. In
addition, formaldehyde as evolved from the flakes has an odor itself.
82
-------
Paraformaldehyde flakes are sold under the brand name Methogen by Vineland
Laboratories of Vineland, New Jersey.
83
-------
SECTION XII
USE OF SOIL FILTERS TO REMOVE ODORANTS
QO
The use of soil beds for odor control was reported by Carlson and Leiser.
Their tests indicated that odor reduction was affected by microorganisms
in the soil rather than by ion exchange, chemical combination or oxidation.
Moist loam soils were found to have the greatest odor removal possibili-
ties. Over a three-month test period, hydrogen sulfide gas concentrations
of 15 ppm at a flow rate of 107 1 per min per sq m (0.35 cu ft per min per
sq ft) of soil surface were reduced to an imperceptible level in 81 cm
(32 in.) of soil. For a flow rate of 103 1 per min per sq m (0.34 cu ft per
min per sq ft) and a hydrogen sulfide concentration of 9.5 ppm, 90 percent
of the hydrogen sulfide was removed in the first 46 cm (18 in.) of soil.
Effectiveness of the soil beds in removing the hydrogen sulfide did not
diminish during a three-month test period. A soil filter for the removal
of odors from a Mercer Island pumping station in Washington has been in
successful operation for three years.
84
As an outgrowth of the earlier work, Carlson and Gumerman proposed a
system for the treatment of odorous gases. Their system included a per-
forated tile system through which the odorous gases were blown. Above
the tile system the soil was covered with a greenhouse to facilitate year-
round plant growth. The role of the plants within the system was to keep
the structure open, to utilize some of the excess sulfur, and to replenish
the soil organic matter that is sacrificed in the active biological growth
which occurs. They suggested a plant with a shallow root system which
would meet the above goals but not interfere with the gas distribution
piping system.
Investigating soil columns as a means of removing odor, Gumerman and
rt c
Carlson proposed a two-stage process: an absorption and a rejuvenation.
The rejuvenation or oxidation stage requires the presence of oxygen. In
designing a soil column for the absorption of H_S, they listed the follow-
ing considerations:
85
-------
(a) Detention time
(b) Temperature
(c) Quantity of EJ5
(d) Initial H-S concentration
(e) Gas flow rate
Hydrogen sulfide was removed by both wet and dry soil columns. For the
wet columns, absorption seemed to be the responsible mechanism. Better
removals were obtained at pH 8 than at either pH 4.0 or 5.8, suggesting
that the hydrosulfide ion HS, not H_S, is the active specie. Removal
2+ 3+ 2+ 2+
was enhanced by the presence of Cu , Fe , Zn and Ni ions at the
soil surface.
Hydrogen sulfide removals were more efficient in dry than in wet soils.
The dry soil reactions were postulated to be a two-stage surface catalyz-
ed process.
H0S removal: M0_ + H9S •* MSV + H_0 (25)
.& A. Z A 2.
MO is the cation oxide present at the removal site
A.
Rejuvenation: 2 MSX + XH20 •> 2MOX -I- Sulfur (26)
The limitation on the number of possible rejuvenations is caused by the
steric hindrance from deposition of sulfur at the removal site. The same
metal ions as listed for the wet soil system are desirable for the dry
* 85
system.
The use of soil filters for the removal of animal waste odors was investi-
27
gated by Burnett and Dondero. They based their initial trials on the
go oc
earlier work of Carlson and Leiser and Gumerman and Carlson and found
that, indeed, the use of soil columns was effective in removing both hy-
drogen sulfide and ammonia from the head-space gas over decomposing poultry
manure. They found that for ammonia concentrations of up to 200 ppm, re-
movals of 100 percent were obtained and for hydrogen sulfide concentrations
of 22 to 100 ppm more than 95 percent removal occured throughout a three-
month, continuous testing period. They further found that when the soil
86
-------
columns dried, the ammonia removal efficiency dropped rapidly. Thus, to
be fully effective, the moisture content of the soil must be maintained.
By mixing manure with the soil prior to using it in the column, the mois-
ture-holding capacity was increased. As a result of their work they made
some tentative suggestions as to the area required for odor removal.
Assuming a 40,000-layer operation, they suggested that a trench 0.61 m
(2.0 ft) deep, 0.61 m (2.0 ft) wide and 276 m (903 ft) long would be re-
quired to deodorize the air. This is equivalent to 2.55 1 (0.0903 cu ft)
of soil per bird.
27
As a part of this study, Burnett and Dondero attempted to determine the
pressures required to force air through the soil columns at various depths.
The columns they were using were 15 cm (6.0 in.) diameter plexiglass with
a shallow layer of gravel just above the gas inlet. For untreated soil
they were using, a back pressure of 13 cm (5.0 in.) of water was sufficient
to cause 30 1 (1.1 cu ft) per min of air to pass through a 0.61 m (24 in.)
depth of soil. For the soils to which some manure had previously been
added, this pressure was reduced to approximately 6.4 cm (2.5 in.) of
water under the same conditions. Thus, one may expect wide variations in
the pressures required to gain the necessary volumetric gas flow.
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SECTION XIII
USE OF PROPRIETARY ODOR CONTROL CHEMICALS
When two odorants are mixed the resultant has a different odor from that
of the original components, even though no chemical reaction may take
place. When the odor of the mixture is more pleasant than that of
one of its components, the process may be considered to be a method of
odor control by which an unpleasant odor (malodor) is mixed with another
substance (controlling agent). Such processes are called odor cqunter-
action, odor masking, odor cancellation, odor neutralization or reodoriza-
tion. The specific meanings of some of these terms are discussed below.
The literature contains early reference to "odor pairs", odorous gases in
proportions that make the mixture odorless or nearly odorless; for example,
rubber and cedarwood, musk and butter almond, skatole and coumarin, and
butyric acid and oil of juniper. These original odor measurements were
dilution-to-threshold ratios and the reduction in these values resulting
from mixing a malodor with a controlling agent is called "odor counter-
action". Odor counteraction is considered to be the phenomenon whereby
odor intensity, however measured, is reduced by adding a non-chemically-
reactive controlling agent to a malodor.
The term "odor cancellation" implies complete counteraction or reduction to
an odorless condition. "Odor neutralization" is also used in this sense,
although the chemical implication of this term (as in acid-base neutrali-
zation) may be confusing. No generally accepted physiological mechanism
explains this phenomenon; some investigators question its reality. In the
absence of a generally accepted scale of odor intensity, it is difficult
to say what "nearly odorless" really means.
When a malodor is changed in quality by mixing with a control agent,
especially when the change is so extreme that the malodor is rendered
unrecognizable, the process is called "odor masking". To the extent that
masking makes a malodor less objectionable, it is a method of odor con-
trol. Odor control by masking and by counteraction have similar operational
89
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requirements and are frequently indistinguishable from each other in
practice, even though their objectives are presumably different.
Several chemicals are available to livestock producers to control odor.
These chemicals, although seldom sold on the basis of composition but on
the basis of brand names and specific company formulations, are generally
thought to behave in one of several ways. Chemicals are sold which will
modify the pH or in some other way inhibit biological degradation. These
chemicals are thus designed to inhibit odorous gas formation. A second
group of chemicals commonly called masking agents have a particular odor
of their own and are designed to overcome the manure odor with the odor
of the chemical additive. Counteractants, as the name implies, are gen-
erally mixtures of aromatic oils selected to counteract the odor of the
components in the waste. Another group, the deodorants, is a formulation
designed to eliminate the malodor of the waste generally without adding
an additional covering odor. The final classification is the digestive
deodorant which is generally a combination of enzymes and aerobic and
anaerobic bacteria designed to modify the biological process of degrada-
tion in such a way as to alter the odorous compounds produced.
Deibel performed odor abatement studies on liquid poultry waste using
a number of chemicals and proprietary compounds. Additions of sodium
chloride up to eight percent (weight/volume) or of commercially available
powdered bacterial starter cultures (digestive deodorants) to the waste
as well as direct ozone treatment failed to abate the odor. Addition of
lime abated the odor for seven to 10 days, but after one week, the strong
odor of ammonia was readily detected regardless of the lime concentration.
The addition of hypochlorite to the waste caused the evolution of chlorine
gas, presumably from the reaction of the hypochlorite and uric acid. The
addition of 50 ppm of chloramine-T rapidly deodorized the manure, but the
odor returned within 24 hours. The cost of treating the waste with chlor-
amine-T immediately prior to removal and spreading of the manure was com-
puted to be $5,000 annually for a 25,000-bird operation.
86
A report from England regarding the addition of odor control compounds
to liquid poultry manure indicated that good odor control could be achieved
90
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by the use of the commercial masking agent added directly to the manure
slurry at the rate of 25 to 50 ml per cu m (one to two pints per 10,000 gal.)
prior to spreading. Costs for such treatment were estimated at three to
O/:
nine cents per cu m ($1.20 to $3.60 per 10,000 gal.) of liquid manure.
Q/1
A study was conducted by Burnett and Dondero in which a variety of mask-
ing agents, counteractants, deodorants, and digestive deodorants were
evaluated - first in a laboratory study, then in a field operation - to
determine their effectiveness. Odor panels were used to evaluate the simi-
larity of the odor of treated manure samples receiving various concentra-
tions of the odor chemicals. For evaluation of the chemical counteractants,
the deodorants, and masking agents, 500 ml of the waste was placed in a
screw cap quart jar. Each jar then received a quantity of the chemical
being tested. The quantities ranged from zero to 3.2 g of the appropriate
chemical per jar. For the evaluation of the digestive deodorants, which
required an incubation period for action to take place, the waste sample
was placed in the jars, the chemical added, and then the material allowed
to incubate at room temperature for 28 hours. A sample was withdrawn and
placed in the test vial.
Data were collected in terms of an index of similarity (D). This index is de-
fined as the square root of the sum of the squared differences between the
panel ratings for the nine concentrations of chemical and the control. Thus,
the D index was a measure of the effectiveness of the odor control chemicals.
A low value indicated lack of effectiveness and a high index meant the treated
liquid manure was highly dissimilar to untreated liquid manure. Their results
indicated that some chemicals were effective in controlling the odors immedi-
ately after addition to the waste. This would be equivalent to adding odor
control chemical to a storage pit immediately before spreading the waste on
cropland. The masking agents and counteractants were found to be most effec-
tive odor control products, deodorants were moderately effective, and diges-
tive deodorants were least effective. The cost of treating liquid poultry
manure with an effective animal odor control product (masking agent) was
estimated to be 37 cents per cu m ($14.00 per 10,000 gal.) of liquid ma-
nure based upon brief field study. A list of odor control product manu-
facturers was included in their report. That list is given in Table 33,
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along with additions which have become available since then.
Table 33. MANUFACTURERS OF ODOR CONTROL PRODUCTS FOR USE IN CONTROLLING
MANURE ODORS 36'87
Agriaids, Inc.
Div. of Flavor Corp.
of America
3037 N. Clark St.
Chicago, 111. 60657
Airkem, Inc.
P.O. Box 203
Commerce Rd.
Carlstadt, N.J. 07072
Albert Verley & Co.
124 Case Drive
S. Plainfield, N.J.
07080
Allied Chemical Corp.
Solvay Process Div.
40 Rector Street
New York, N.Y. 13209
Blenders, Inc.
6964 Main St.
Lithonia, Georgia
Chloroben Chem. Corp.
Belleville Turnpike
Kearny, N.J. 07032
Dodge & Olcott, Inc.
P.O. Box 273
Old Chelsea Sta.
New York, N.Y. 10011
Florasynth, Inc.
900 Van Nest Ave.
P.O. Box 12
Bronx, N.Y. 10462
Fritzsche Bro., Inc.
76 Ninth Ave.
New York, N.Y. 10011
Givaudan Corp.
321 W. 44th St.
New York, N.Y. 10036
Gland-0-Lac Co.
19th & Leavenworth
Omaha, Nebraska
International Flavors
& Fragrances, Inc.
521 W 57th Street
New York, N.Y. 10019
Kalo Company, The
Quincy, 111. 62301
Martin Bio-Chem
710 E. Southern Ave.
Mesa, Arizona 85201
Miles Chemical Co.
1127 Myrtle St.
Elkhart, Ind.
Nilodor Co., The
60 E. 42nd Street
New York, N.Y. 10017
Noville Essential
Oil Co., Inc.
1312 Fifth Street
North Bergen, N.J.
07047
Orbis Products Corp.
475 Tenth Ave.
New York, N.Y. 10018
Perry Brothers, Inc.
61-12 32nd Ave.
Woodside, N.Y. 11377
Reliance Chem. Co.
P.O. Box 19343
Houston, Texas 77024
Rhodia, Inc.
600 Madison Ave.
New York, N.Y. 10022
S.B. Penick & Co.
100 Church St.
New York, N.Y. 10007
Sep-Ko Chemicals, Inc.
3900 Jackson St. N.E.
Minneapolis, Minn.
55421
Somis Chemical Co.
Somis, California
U.S. Gypsum Co.
300 W. Adams St.
Dept. 139
Chicago, Illinois
Vineland Labora-
tories , Inc.
Vineland, N.J.
08360
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SECTION XIV
WASTE MANAGEMENT TECHNIQUES TO MINIMIZE ODORS
Because of technical difficulties in odor measurement and the large num-
ber of variables involved, only limited data exist relating odor produc-
tion and specific manure handling techniques. There has developed, how-
ever, an extensive collection of observations relating odors with waste
handling practices. Most of these observations were made incidental to
other studies and thus are scattered throughout the total accumulated
literature. An overview indicates that certain operations are most like-
ly to be sources of odor.
OPEN LOTS
Animals have traditionally been raised outside in much of our country.
When raised in a sufficiently low density to allow a vegetative ground
cover to be maintained, little odor was produced. The manure was widely
dispersed and during warm weather dried rapidly. Odorous compounds that
were released were diluted sufficiently to avoid odor problems. Nutrients
in the urine and feces were incorporated into the soil resulting in a
labor-, odor- and pollution-free manure management system.
Increased animal density, as found in cattle feedlots, hog lots and some
poultry operations, results in eliminating the vegetative ground cover
and the advent of manure management. The water pollution potential of
such operations has been well documented and need not be of concern in
this report. The odor potential of outdoor confinement units is largely
related to manure management, but the operator has definite limits because
of climatic and geographical limitations. When the manure accumulated on
the soil surface is wet (70 percent moisture or above) anaerobic decompo-
sition is possible. When the manure is both wet and warm, anaerobic bac-
teria flourish, and odors are likely to occur. Coupled with odor release
from the lot surface is the tendency of animals to lie or roll in the wet
manure for its cooling effect. A manure-covered animal perhaps represents
the epitome of odor generation because heat of the animal stimulates bac-
terial metabolism.
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Site selection and facility design are of paramount importance in con-
trolling odors of this type. Good drainage and proper orientation to
achieve the maximum drying rate are important. Feedlots in areas of the
country with low, summer rainfall have definite advantages in this res-
pect. Adequate slope is also helpful in maintaining a dry lot. Slopes
of four to six percent are generally preferred for unsurfaced lots. Con-
crete-surfaced lots may have a lesser slope and still be satisfactory.
The use of concrete pavement around feeders and waterers in areas of
heavy animal usage also can be helpful in promoting a dry lot. Mounds
are frequently used to provide animals a dry place to lie down if drain-
age is marginal.
An unroofed feeding pen can be operated in a manner to minimize the ex-
tent of anaerobic decomposition. Regrading to eliminate poor drainage
that develops from animal activity can speed manure drying in those areas.
Prompt repair of leaking waterers is another method. Manure removal fre-
quency-has been suggested as an odor control technique but is limited
during wet periods. Odor control chemicals have been used by some oper-
ators but their results are difficult to predict and chemicals are often
expensive.
Of greatest importance with respect to site selection is proximity to other
commercial operations, recreational areas and homes. Although no legally
defined distances exist beyond which odors of nuisance level will not
occur, separation is of great value in achieving natural odor dilution.
Nuisances have been established in courts at distances of 300 m (1,000 ft)
downwind from operations where anaerobic storage tanks were uncovered and
vented to the atmosphere. Thus, a 0.8 km (0.5 mile) separation from resi-
dences is a desirable minimum. Greater distances from communities, housing
developments, commercial areas, parks or other points where people are
likely to gather are appropriate.
Visual screening, landscaping, or other means to eliminate the suggestion
of a potential odor source are often helpful in avoiding odor complaints.
The untidy appearance of a livestock operation can be detrimental because
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of the subjective nature of odors and the fact that people are subject
to suggestion of odors.
In discussing techniques for the control of odors from cattle feedlots,
88
Paine described the odors as being due to the anaerobic decomposition
of manure on the feedlot surface. Also listed as odor-contributing areas
were the retention basins used to collect feedlot runoff. The key to
odor control was described in terms of controlling the oxygen and moisture
content of the organic materials which produced the odor. Maintaining the
feedlot surface with an overall slope between 2.0 and 4.0 percent to remove
excess moisture from the pens and to prevent low spots which accumulate
moisture were suggested. Mounds were recommended in flat feedlots which
otherwise would not provide adequate drainage or a dry, clean spot for
animals to rest. The addition of straw or other fibrous material was
suggested where better footing is required in wet manure and also to re-
duce the moisture content. Sprinkling the feedlot surface during dry
weather was recommended to control dust and to increase aerobic manure
decomposition. Methods suggested for minimizing odors associated with
manure holding ponds included solids removal prior to allowing the water
to enter and the use of surface aeration equipment. When manure must be
stockpiled prior to disposal, the use of long, narrow rows was suggested.
Such rows are compatible with available composting equipment and are help-
ful in the control of fires.
CONFINEMENT BUILDINGS
Confinement livestock production has many potential economic and labor
utilization advantages. To capitalize on these advantages, a higher
degree of sophistication is required in planning, design, construction
and operation than when range or pasture production is utilized. Odor
production is related to several aspects of the system and, therefore,
needs to be considered in the overall planning process. Just as in the
case for unroofed systems, site selection and visual considerations are
of paramount importance.
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ANIMAL-MANURE SEPARATION
The initial manure management operation which has an important influence
on odor production is separating the animal from its manure. If manure
remains in the pen with animals, they will inevitably pick up a portion
of it on their bodies and increase the odor-generating surface. The
warmth of their bodies contributes to the decomposition and an odorous
building results. Several schemes have evolved for rapid separation of
animals and manure.
Among the most common are slatted floors and frequent-flushing, solid-
floor systems. Each of these concepts has worked satisfactorily and when
properly designed and operated can provide clean animals. Slatted floors
may be used in the entire pen area or in a limited area, partially slatted.
Although more expensive, the totally slatted floors have more reliably pro-
vided clean animals. Flushing systems are highly varied in their design,
ranging from manual, daily hosing of the floor to automatically flushing
gutters and alleyways which are designed to promote defecation in the
flushed area.
Caged poultry systems overcome this problem by having the cages suspended
so that droppings pass immediately through the cage floor to a storage or
drying area. When poultry is raised in a floor system, the floor frequent-
ly serves as the storage area. Under this system the manure pack is man-
aged to limit the moisture level so that anaerobic decomposition does not
occur. Litter is the frequent aid used to achieve this end.
MANURE STORAGE
From a biological point of view, hence an odor point of view, storage of
manure cannot be realistically separated from treatment. In liquid and
semisolid storage systems, biological activity continues throughout the
storage period unless inhibited by low temperature or some alternate bio-
logical restraint. In typical, manure storage tanks, anaerobic decompo-
sition is continually in progress but in a container not specifically
96
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2
designed for that purpose. For example, Miner suggests that for an
anaerobic lagoon a volume of 12.5 1 per g (200 cu ft per Ib) of volatile
solids per day should be provided. In a storage tank designed for swine
wastes, 30 days storage, 1.56 cu m of storage volume per kg of animal
(25 cu ft of storage volume per thousand pounds of animal) would retain
the waste. This is equivalent to 0.26 1 per g (4.2 cu ft per Ib) of
volatile solids added per day. Thus, it is consistent that the odor of
manure storage tanks is typical of overloaded lagoons or septic tanks.
Most odor complaints are related to manure storage and, thus, the great
majority of research data available concerns this source. Of particular
concern are the gases and odors released upon agitation of a manure stor-
age tank. When a storage tank beneath a slatted floor is agitated, ani-
mals over the tank are subject to high concentrations of gaseous products
of decomposition. Animals have been killed under these conditions.
One step to reducing odors from manure storage tanks has been to locate
the tanks outside the building and to keep them covered which inhibits
the escape of gases from the liquid surface. By having the storage tank
outside the building, hazards to the animals from gas release upon mixing
are reduced but the difficulty in getting manure into the tank is in-
creased.
An additional method of reducing odor from manure storage tanks is to
reduce the storage period. Both research and field observations indicate
the odor intensity and offensiveness increase with storage period.
Inhibition of anaerobic metabolism during storage can be effectively used
to reduce odors. Among ways to accomplish this are: (a) adding sufficient
oxygen to maintain aerobic conditions, usually by aeration; (b) reducing
the moisture content to inhibit degradation (drying); and (c) inhibition
of biological activity by chemical means.
In aeration for odor control, aerobic activity is the main mode of de-
gradation. Although the gaseous by-products of aerobic degradation have
97
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not been as extensively studied as those from anaerobic treatment, they
are generally nonodorous and, therefore, not objectionable. The gases
are more highly oxidized in nature. The most common aerobic storage de-
vice in use is the oxidation ditch. The design and operation of oxidation
ditches were
age devices.
2
ditches were described by Miner. Aerated lagoons also are aerated stor-
Drying manure as a means of reducing odors and volume has received wide-
spread application in the poultry industry. Basically, the cages are
suspended over a manure storage pit into which the droppings fall. Suf-
ficient ventilation is provided in the pit to dry the manure. By follow-
ing this procedure, it is possible to obtain extended storage periods.
Diligent, operator control is required, however, to prevent water spills
or other extraneous water from entering the pit and exceeding the drying
capacity of the ventilation system.
Several attempts have been made to find chemicals that will prevent odor
production for addition to manure storage tanks. These are treated in
considerable detail in Section IX. Thus far, none of the materials sug-
gested have been fully satisfactory or at a price that was acceptable.
ANAEROBIC LAGOONS
Anaerobic lagoons have been used in animal waste management systems for
the last ten years. Originally they were conceived as a treatment and
disposal device, but it soon became evident that in all but the most arid
regions lagoons filled and the removal or discharge of effluent was neces-
sary. Secondly, it was also determined that effluent from an anaerobic
lagoon was not of suitable quality to discharge to most streams and the
most acceptable alternative was to apply the effluent to cropland. Thus,
the anaerobic lagoon also must be regarded as having a primary storage
function and achieves considerable solid breakdown to liquid during the
storage. Because of this action, the lagoon effluent is generally more
amenable to pumping than fresh manure and can, therefore, be applied to
cropland using conventional irrigation equipment.
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The odor of anaerobic lagoons has been, described throughout the range of
nonoffensive to highly offensive. A primary cause of objectionable odors
from lagoons is organic overload. When a lagoon contains a large concen-
tration of fresh manure which is high in easily decomposable organic
matter, the acid-forming bacteria proliferate and produce a large concen-
tration of odorous intermediates including organic acids. The methane-
forming bacteria, whose role is to convert organic acids to methane, grow
less rapidly than the acid-forming group. As long as this imbalance exists,
odorous compounds will accumulate in the water and some will escape to the
air. If the imbalance is severe, the me thane-forming bacteria will be
inhibited in their growth and the odorous condition may persist. Such
overloads may be the result of either faulty design, inadequate volume,
or poor management. Overloads are particularly common in the spring when
the lagoon, which has been receiving manure all winter, finally warms
sufficiently for acid-forming bacteria to attack the accumulated manure.
Again, there is a rapid production of organic intermediates and an insuf-
ficient number of methane formers to utilize them.
The intensity and duration of objectionable odors from anaerobic lagoons
can be minimized by providing an adequate water volume so the spring
surge in organic acid concentration will be diluted. Overloaded condi-
tions also are avoided by adding wastes frequently rather than in large
quantities at irregular intervals. Parallel, rather than series, opera-
tion of multiple lagoons makes more uniform use of the lagoon available,
hence reducing the tendency to cause overload.
Even with good design and proper management, however, anaerobic lagoons
will still produce an odor. Whether this odor production is acceptable
will depend upon other environmental factors such as the proximity to
neighbors and the general odor criteria of the area.
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SECTION XV
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47. Koelliker, J. D., and J. R. Miner. Desorption of Ammonia from An-
aerobic Lagoons. Trans. Amer. Soc. Agr. Engin. 16(1);148-151,
1973.
48. Deibel, R. H. Biological Aspects of the Animal Waste Disposal Pro-
blem. In: Agriculture and the Quality of Our Environment. Nyle
C. Brady, Ed., Amer. Assoc. for Advancement of Science., Pub. No.
85, Washington, D.C. 1967. p. 395-399.
49. Bell, R. J. Aeration of Liquid Poultry Manure: a Stabilization Pro-
cess or an Odor Control Measure. Poultry Sci. _50:155-158, 1971.
50. APHA. Standard Methods for the Examination of Water and Wastewater.
13th Edition. American Public Health Assn. Washington, D. C. 1971.
51. Ludington, D. C., A. T. Sobel, and A. G. Hashimoto. Odors and Gases
Liberated from Diluted and undiluted Chicken Manure. Amer. Soc.
Agri. Engin. Paper 69-462. June 1969.
52. Hashimoto, A. Aeration Under Caged Laying Hens. Trans. Amer. Soc.
Agri. Engin. _15_:1119-1123, 1971.
53. Fosnaugh, J., and E. R. Stephens. Identification of Feedlot Odors.
Final Report. Dept. HEW, PHS Grant No. UI 00531-02. Statewide
Air Pollution Research Center, University of California, Riverside.
1969.
54. Bethea, R. M., and R. S. Narayan. Identification of Beef Cattle
Feedlot Odors. Trans. Amer. Soc. Agri. Engin. 15:1135-1137, 1972.
55. Day, D. L., E. L. Hansen, and S. Anderson. Gases and Odors in Con-
finement Swine Buildings. Trans. Amer. Soc. Agri. Engin. 8^:118-121,
1965.
56. Hartung, L. D., E. G. Hammond, and J. R. Miner. 1971. Identification
of Carbonyl Compounds in a Swine Building Atmosphere. In: Livestock
Waste Management and Pollution Abatement. ASAE Publication PROC-271.
1971. p. 105-106.
57. Lebeda, D. L. , and D. L. Day. Waste-Caused Air Pollutants are Mea-
sured in Swine Buildings. Illinois Res. (Fall) 1965. p. 15.
58. McCalla, T. M., and L. F. Elliott. The Role of Microorganisms in the
Management of Animal Wastes on Beef Cattle Feedlots. In: Livestock
Waste Management and Pollution Abatement. ASAE Publication PROC-271.
1971. p. 132-134.
104
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59. Frus, J. D. , T. E. Hazen, and J. R. Miner. Chemical Oxygen Demand
as a Numerical Measure of Odor Level. Trans. Amer. Soc. Agr. Engin.
_L4:837-840, 1971.
60. Jacobs, M. B. The Chemical Analysis of Air Pollutants. Interscience
Pubs. Inc. New York, N.Y. 1960.
61. Kowalki, 0. L. , 0. A. Hougen, and K. M. Watson. Transfer Coefficients
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62. Mourn, S. G. , W. Seltzer, and T. M. Goldhaft. A Simple Method of Determin-
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63. APHA. Methods of Air Sampling and Analysis. American Public Health
Assn. Washington, D.C. 1972.
64. Sawyer, C. N. Chemistry for Sanitary Engineers. McGraw-Hill. New
York. 1960. p. 336-341.
65. Sawyer, C. N. and P. L. McCorty. Chemistry for Sanitary Engineers.
Second Edition. New York, McGraw-Hill. 1967. p. 479-485.
66. Earth, C. L. , D. T. Hill, and L. B. Polkowski. Correlating Oil
and Odorous Components in Stored Dairy Manure. Amer. Soc. Agr. Engin,
Paper 72-950, December 1972.
67. Barneby-Cheney. Scentometer: An Instrument for Field Odor Measurement,
Instruction Sheet 9-68.
68. Huey, N. A., L. C. Broering, G. A. Jutze and C. W. Gruber. Objective
Odor Pollution Control Investigations. Jour. Air Poll. Control Assn.
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69. Rowe, N. R. Odor Control with Activated Charcoal. Jour. Air Poll.
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71. Ingram, S. H. , R. C. Albin, C. D. Jones, A. M. Lenon, L. F. Tribble,
L. B. Porter, and C. T. Gaskins. Swine Fecal Odor as Affected by
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72. Albin, R. C. Swine Fecal Odor as Affected by Feed Additives. Texas
Tech. University. Personal Communication. 1973. 4 p.
73. Feedlot Management. Sagebrush for Odor Control: In the Feed or in
the Manure? Feedlot Management 14(5) :74, 1972.
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74. Day, D. L. Liquid Hog Manure Can Be Deodorized by Treatment with
Chlorine or Lime. Illinois Research. (Summer) 127. 1966. p. 16.
75. Yushok, W., and F. E. Bear. Poultry Manure: Its ?^«^lo;^e-
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76 ' ^iopmen; of Smell in Poultry Droppings Slurry Pits. Report from
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Derby, England. 1967.
77 Faith W. L. Odor Control in Cattle Feed Yards. Jour. Air Pollut.
Control Assoc. L4:459-460, 1964.
78 Posselt H. S., and A. H. Reidies. Odor Abatement with Potassium
Permanganate 'solutions. Ind. Engin. Chem. Product Research and
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80 O'Neil E T. Manure Odor Abatement with Hydrogen Peroxide. Personal
Co^unication. FMC Corporation Report No. 4760-R. Princeton, New
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82 Seltzer W. S. G. Mourn, and T. M. Goldhaft. A Method for the Treat-
ment of Animal Wastes to Control Ammonia and Other Odors. Poultry
Sci. .48:1912, 1969.
83 Carlson D. A., and C. P. Leiser. Soil Beds for the Control of Sew-
agl Odors. Jour. Water Pol. Control Fed. 34:829-840, 1966.
84. Carlson, D. A., and R. C. Gumerman. Hydrogen Sulfide and Methyl Mer-
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Conference. Purdue Univ. Engin. Lafayette, Ind. 1966.
85. Gumerman, R. C., and D. A. Carlson. Chemical Aspects of Odor Removal
in Some Soil Systems. In: Animal Waste Management. Cornell Univ.
Conf. on Agri. Waste Management. 1969. p. 292-302.
86 Burnett W. E., and N. C. Dondero. The Control of Air Pollution (Odors)
from Animal Wastes - Evaluation of Commercial Odor Control Products
by an^rganoleptic Test. Amer. Soc. Agri. Engin. Paper 68-909, Decem-
ber 1968.
106
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87. Willrich, T. L. Manufacturers of Odor Control Chemicals for Use in
Controlling Manure Odors. Oregon State University. Personal
Communication. 1973. 2 p.
88. Paine, Myron D. Feedlot Odor. Cooperative Extension Project GPE-7.
Pub. GPE-7800. Oklahoma State University. 1973.
107
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SECTION XVI
APPENDICES
A. Partial List of Proprietary Odor Control Chemicals 110
for Livestock Wastes
B. Summary of Selected Court Cases Relative to Livestock 113
Odors
109
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APPENDIX A
PARTIAL LIST OF PROPRIETARY ODOR CONTROL
CHEMICALS FOR LIVESTOCK WASTES
Manufacturer:
Product:
Type:
Application rate:
Cost:
The Kalo Co.
2620 Ellington Rd.
Quincy, 111. 62301
Kalo K. 0.
Digestive deodorant, dry powder
3 lb/1,000,000 gal. Lagoon waste
0.5 Ib/ton manure
0.5 lb/10,000 sq ft floor area
$1.50/lb in 500 Ib lots (3-70)
Product:
Type:
Application rate;
Cost:
Kalo 0. M.
Odor maskant, liquid concentrate
Applied by diluting 1 cup to 50
gal. water, oil, or insecticide
and spraying
$5/pint in 100 pint drum
Manufacturer:
Product:
Type:
Application:
Manufacturer:
Product:
Carus Chemical Co.
1500 Eighth St.
La Salle, 111. 61301
Cairox (potassium permanganate)
Odor oxidant
1. Spray a 1 percent solution on
feedlots at 20 Ibs/acre
2. Mix 5 Ibs of Cairox per 1000
gal. liquid manure or spray a
1 to 4 percent solution on
tank at the same rate
Nilodor, Inc.
7740 Freedom Ave., N. W.
North Canton, Ohio 44720
Nilodor Superconcentrate
110
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Type:
Application:
Cost:
Odor neutralizer
Concentrate volatilizes from an
automatic dispenser. One dis-
penser every 10 ft of wall
$39.15 per qt in 4 qt lots (11/72)
Product:
Type:
Application:
Nil-0-Sol
Nilodor plus detergent
Dilute 1 qt to 16-32 gal. as a
cleaning solution
Manufacturer:
Product:
Type:
Application:
Vineland Laboratories, Inc.
2285 E. Landis Ave.
Vineland, N.J. 08360
Methogen
Reacts with ammonia, fumes bacterio-
cidal
1 Ib methogen per 100 Ibs manure
Manufacturer:
Product:
Type:
Application;
Product:
Type:
Application!
Wayne Animal Health Aids
Allied Mills, Inc.
110 N. Wacker Drive
Chicago, Illinois
Wayne D-ODOR #1
Bacteria culture and enzymes
Product is placed in water suspen-
sion and applied to manure-covered
surfaces where slurries are not the
problem. One ounce per 1000 sq ft
weekly
Wayne D-ODOR #2
Bacteria culture and enzymes
Water suspension is applied to ma-
nure slurries or other liquids at
the rate of 1 Ib per 10,000 gal.
of material.
Ill
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Manufacturer:
Product:
Type:
Application;
Cost:
Game Slatted Floor Co.
Box 3
Ransom, Illinois 60470
Solution "101"
Odor maskant
Dispensed into the air with a "Pig
Puff" dispenser.
Pig Puffs: $79.50 each
Solution "101": $7.95/gal»
112
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APPENDIX B
SUMMARY OF SELECTED COURT CASES RELATIVE TO LIVESTOCK ODORS
1966 Law Suit Against a Dairy Operation in Washington by Urban Neighbors.
The dairy was on land zoned for general uses with the operation of a dairy
farm, permitted. The land had been used as a dairy farm for many years and
until three years earlier the herd was approximately 50 animals. The land
across the street to the south, zoned suburban agricultural, had been di-
vided into approximately five-acre tracts for homes. The area was typi-
cal of those found on the boundaries of a city.
Those who complained had not recently moved into the area, but most had
been there a number of years. The principal complaint of the 18 plain-
tiffs was that because of the intensified operation of the dairy in the
last three years, odors arising from it had become a nuisance. The herd
number had been increased to 200.
In an effort to solve the problem created by the waste of the dairy ani-
mals, the defendants constructed a large concrete holding tank. All man-
ure was washed into the tank, reduced into a liquid state, and pumped into
a lagoon. An earlier attempt to dispose of the liquid manure by spraying
it on the fields was abandoned because of the odors created and because
drift from the spray fell on adjoining properties. Those who complained
asserted that nauseous odors were emitted from the lagoon. The relief
sought was an injunction from maintaining the open lagoon.
The witnesses testified that the odors were intensely offensive, and that
when the weather was pleasant and conducive to outdoor activities that it
was impossible to carry on these activities because of these odors from
the lagoon. Certain neighbors called by the defendants testified that they
were not greatly affected by odors since their homes tended to be to the
side of prevailing wind patterns.
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The judge made some effort to examine the area and on three occasions drove
on the streets. On each occasion, the weather was cold and the wind rather
brisk but unpleasant odors could be detected. On one occasion, by closer
inspection on foot in the neighborhood of the lagoon, some effort was made
to ascertain the presence of the offensive odors and some unpleasant odor
was noted which was different in quality, and subjectively more offensive
than that generally associated with manure from cattle. The court was of
the opinion that if the odors emitted by the lagoon were of that intense
quality, those in the vicinity, indeed, would be substantially affected
to an unbearable degree.
The problem arose because the increased number of cattle had increased the
manure disposition problem far beyond that which existed when the dairy was
smaller. The defendants have invested about $300,000 in their operation.
They have experimented with manure disposal. They tried to dispose of it
by spraying it on the pasture and abandoned this method at substantial cost
to themselves because of problems which spraying created. They have not
attempted to use the lagoon system and have constructed a lagoon into which
they pump about 100 cu m (27,000 gal.) of liquid manure every two days.
The thrust of the testimony of the expert witnesses was that when they
visited, the lagoon seemed to be operating satisfactorily, and they detect-
ed no unusual odors. However, all seemed to agree, that lagoons are still
experimental and there is a great deal to be learned from them.
From the evidence, the judge found that the operation of the lagoon con-
stituted a nuisance because of the odors which it emitted from time to
time. Evidently, at times it had not functioned properly and there was
no reason to suppose that the condition would not recur. He continued
the case for four months, thereby withholding final judgment, to permit
the defendants to attempt to further cope with this problem by means of
their own choosing, and suggested that they investigate the possibili-
ties of chemical additives; of aeration by the discharge of air in pipes
in the body of the lagoon; of the introduction of algae, if appropriate;
of enlargement of the lagoon system so that overload would not occur, or
114
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by such other means as their own investigation might suggest.
In court action four months later (in April 1966) , a new attorney for the
dairy owner advised the abandonment of the lagoon and the installation of
a series of dug rectangular pits to receive the manure. Black polyethyl-
ene film is used as a cover for the pits. It was the contention of the
attorney, who has a background of chemistry, that the pits would act as
anaerobic ones and that plastic covers would confine odors.
Patz versus Farmegg Products, Inc. (1970).
This was a civil action for injunctive relief and to recover damages sus-
tained on account of a private nuisance. The case was heard in the Dis-
trict Court, Webster County, Iowa, during 1970.
Farmegg Products, Inc. purchased 1.63 ha (4.0 acres) of land in 1969 that
had a common boundary with a 100 ha (240 acre) farm owned and operated by
Mr. and Mrs. Patz. FPI constructed two buildings to grow chickens to lay-
ing age on the four acre tract. These were totally-enclosed, mechanically
ventilated buildings, each confining about 43,000 birds in cages suspended
over 25 on (10 in.) deep pits. Air exchange was provided by the ventila-
tion system to promote manure drying and coning so that the pits could re-
tain the manure produced during the 22 week growing cycle.
At the beginning of each growing cycle, in January and in July 1970, feed
and water spilled by the baby chicks and spilled water from malfunctioning
waterers caused excessive moisture in the manure and wasted feed retained
in the pits. The combination of a high ambient temperature required for
young chicks and a low air exchange rate to maintain a high indoor tem-
perature produced more concentrated odorous gases in the fan-exhausted air.
The Patz residence is located about 300 m (1,000 ft) west-northwest from the
nearest exhaust fan. The Patzes complained about offensive odors and dust
exhausted from the buildings and about manure spillage on the public road
in front of their home.
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Evaluation of climatic data by defendant's counsel indicated that the
probability of odor detection in the Patz house yard would be about one
percent of the time.
Having heard the evidence, the Court found that odors coming from the
poultry buildings were offensive, that they were injurious and dangerous
to the health and comfort of the plaintiffs and thus interfered with the
plaintiffs' right to use and enjoy their residence, and that the invasion
of private rights was substantial and intentional; i.e., the decision to
use the existing system of manure handling without giving consideration
to the distance between the plaintiff's house and the poultry buildings.
For the purpose of determining the defendant's liability for damages, the
court found the conduct of the defendant to be unreasonable.
The court awarded $20,000 in permanent damages to the plaintiffs, and en-
joined the defendant from hauling manure upon the highway abutting the
plaintiffs' premises in such a manner that there was risk of spillage on
the highway. The request for injunctive relief, except as indicated in
the preceding sentence, was denied.
Reference: Patz versus Farmegg Products, Inc., Civil No. 43257 (Iowa Dist.
Ct., Webster Co., Dec. 2, 1970).
Hardin Co. versus Gifford Feed Lots, Inc. (1968).
This case, heard in the District Court, Hardin County, Iowa, during 1968,
concerned a public and private nuisance and noncompliance with zoning re-
gulations.
A land tract of about 12 ha (30 acres) was purchased in 1966, and a commer-
cial feedlot was constructed in an old gravel pit on this land. Gravel had
been mined from the pit before 1930. Use of the tract before 1965 was to
graze, feed and water a few horses and cattle. The landowner constructed
two cattle pens and a shed in the gravel pit in 1965. Gifford Feed Lots,
Inc. expanded the facilities to 10 pens with a combined capacity of about
1,200 head on about two ha (five acres) in 1966. The actual number kept
there ranged from 500 to 1,100 head.
116
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Located in the old gravel pit, the feedlot area was poorly drained even
though the lot area was graded. Shallow drainage ditches were constructed
to collect and convey drainage water to a point from where the pooled
water was pumped to two lagoons located at points of higher elevation.
Manure removed from the feedlot was stockpiled near the rim of the gravel
pit for later field-spreading on adjacent cropland owned by others.
The feedlot was located 240 m (800 ft) northwest of Gifford, an unincorpo-
rated village of about 100 people. Gifford residents complained of offen-
sive odors, flies, and noise from bawling cattle and trucks. They were
also concerned about possible contamination of shallow wells in the vil-
lage.
Having heard the testimony, the Court found that the odors and flies con-
stituted a public and private nuisance that could not be abated by measures
proposed by the defendant. The court also found that Hardin County had
been zoned in 1965 and that the use of lagoons violated the zoning regula-
tions. An injunction was decreed by the Court. No appeal was perfected.
Reference: Hardin Co. versus Gifford Feed Lots, Inc., Civil No. 62-160
(Iowa Dist. Ct., Hardin Co., Dec. 23, 1968).
Trottnow Versus Kullmer (1968).
This case was for damages and an injunction to abate alleged nuisance cre-
ated by offensive odors from a poultry house owned by Kullmer. The case
was heard in the district court of Iowa, Benton County, during 1968. The
poultry house in question was constructed in 1966 to accommodate 12,800
hens. A second, similar house was constructed during March, 1967, thus,
two similar buildings are involved. Manure from the buildings was mech-
anically scraped into one of two large manure holding pits. Manure was
scraped into the pits at weekly intervals or more frequently. Water from
the chicken waterers also was collected in the manure storage pit and on
occasion excess water was added to the manure to ease the scraping problem.
The two manure pits had holding capacities between 2-1/2 and 3-1/2 weeks
117
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production. Rather than have the pits filled, usual operating procedure
was to pump manure to a 5.7 cu m (1,500 gal.) mobile tank for transport to
cropland. The defendants owned 31 ha (77 acres) on which this manure was
applied and some manure was applied to neighbors' farmland. The Trottnow
home is the only home within 0.8 km (1/2 mile) of the chicken houses. The
Trottnow farmhouse is 58 m (190 ft) directly west of the closest chicken house.
The major complaint involved in the lawsuit was the odor emanating from the
chicken houses themselves. Each building had ten 0.91 m (36 in.) exhaust
fans on the sides and the ends of the buildings. All are thermostatically
controlled and operate continuously during warm weather.
The odors from the chicken house being blown to the Trottnow property
were particularly bothersome to tenants of the property. They presented
testimony to the discomfort which they suffered and indicated the odors
were having an adverse effect upon their health. The tenant and his wife
eventually moved from the property and drove back and forth to do the work.
The judge found the chicken laying business was a substantial nuisance to
the owner and occupants of the Trottnow dwelling and specified certain
operational requirements that were to be met by the Kullmers. These
included changes in the ventilation system, the manure handling system,
and manure application practices. In addition, he specified they would
provide some method of preventing noxious odors which would unreasonably
pollute the air at the Trottnow farm buildings. He maintained control
of the case and indicated that if additional problems were evident that
impartial observers should be obtained to make impartial observations as
to whether or not the odors were objectionable. Finally, the judge con-
cluded that Mrs. Trottnow had not at that point suffered compensable
damages but the tenants of her property had, in fact, suffered such. A
sum of $1,365 was awarded, based upon their medical expenses and addition-
al living cost occasioned by the odors.
Reference: Trottnow versus Kullmer. Civil No. 23482 (Iowa Dist. Ct.,
Benton Co., Aug 3, 1967).
118
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Edwards versus Black (1968).
Mr. Black operated a commercial cattle feeding operation in a rural area
near Audabon, Iowa. A group of 19 adjacent property owners charged that
the offensive odors, flies, and noise adversely affected their properties.
The jury found that no nuisance existed in this case and declared the con-
finement operation was a reasonable use of property in that locality.
The verdict indicated:
1) the area in which the feedlots were located was primarily an agricul-
tural area;
2) in spite of the numerous homes in the area, the feedlot was a reason-
able use for that area;
3) the odors had not polluted the air in and around the plaintiff's pro-
perties;
4) the defendant had not used his property so as to endanger the health
of the plaintiffs;
5) the operation and maintenance of the feedlot did not constitute a
nuisance nor result in damages to the plaintiffs;
6) the operation of the feedlot did not constitute a. continuing nuisance
The decision was reached primarily on the basis of location. Although
some consideration was given to distance from the residences as an element
of location, the more important consideration was the character of the
surrounding area. Thus, because the surrounding area was predominantly
rural, the facility was judged as being properly located.
Reference: Iowa Law Review. 1971. "Ill blows the wind that profits no-
body:" Control of odors from Iowa livestock confinement facilities.
57(2):451-505. Edwards versus Black. Civil No. 15235-J28-170 (Iowa Dist.
Ct. Montgomery Co., November 5, 1968).
Spencer Creek Pollution Control Association versus Lane Feedlots (1970).
This case was brought by an association of residents and land owners
against a cattle feedlot near Eugene, Oregon. The complaints were of sur-
face water pollution, groundwater pollution, odors, spread of animal dis-
ease, unsightliness, and insect and rodent infestation. The plaintiffs
119
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sought monetary damages and an injunction to preclude cattle raising on
the property.
The feedlot had capacity for approximately 1,000 head and expansions were
proposed to increase this to 1,500 head. The operation included the
feeding of beet top silage during a portion of the year which contributed
to the odor and drainage problems.
After lengthy testimony and argument, the following orders were decreed:
1) Runoff of contaminated water to be kept from the nearby creek.
2) No more than 600 head of cattle were to be maintained on the property.
3) The amount of beet silage to be fed was limited.
4) Continued efforts to reduce odor escape were required.
5) Damages were awarded to the various plaintiffs in amounts ranging
from $15 to $1,850.
Reference: Spencer Creek Pollution Control Association versus Organic
Fertilizer Co. Case No. 96125. Circuit Court for the State of Oregon for
Lane County. August 25, 1970.
Crandall versus Biergans (1972).
In this case the plaintiffs were seeking damage payment and an injunc-
tion against W. H. Biergans who constructed a swine finishing barn on
his property in 1965. They claimed that the swine operation constituted
a private nuisance because obnoxious odors and toxic gases emanating from
the barn were carried by the prevailing wind to the plaintiffs' property.
Secondly, it was asserted that the Michigan Environmental Protection Act
of 1970 had been violated because of air pollution.
The swine building in question, 37 m (120 ft) long by 10 m (32 ft) wide
had a partially slatted floor. A manure storage tank 2.44 m (8.0 ft)
wide and 1.83 m (6.0 ft) deep ran the length of the building along the
center line. Manure, removed from the storage tank by a vacuum tank wagon,
was spread on the defendant's cropland as a crop fertilizer. Four 46 cm
(18 in.) exhaust fans were mounted along the east side of the confinement
barn to provide ventilation.
120
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In his opinion, the judge concluded that (a) the swine building was in an
area zoned agricultural and it was a farming area, and (b) the defendants
were conducting their operation in a husbandlike manner and were not neg-
ligent in their maintenance.
The court decided in favor of the defendants. They were not maintaining
a nuisance. On the basis of the evidence presented, the injury suffered
by the plaintiffs was not of such a substantial nature as to warrant an
injunction against the swine operation or the relocation of the barn as
long as the defendant continued his operation in a careful and husbandlike
manner and used such odor control products or devices as are economically
feasible.
With respect to the Environmental Protection Act, the court determined
there were no standards to judge this operation with respect to odors,
therefore, it did not serve as a basis for any relief to the plaintiffs.
Reference: Crandall versus Biergans. Michigan Circuit Court, Clinton
County, File No. 844. February 14, 1972.
Warden versus Sinning (1970).
This was a civil action seeking damages and injunctive relief because of
a private nuisance caused by offensive odors from a hog operation. The
case was heard by a jury in the District Court, Marshall County, Iowa,
during 1970.
Mr. and Mrs. Leonard Warden, the plaintiffs, live on a grain and livestock
farm in a home that is located directly across the road from the farmstead
on the Sinning property. Mr. Warden has lived on his property 46 years.
The Sinning property is also a grain and livestock farm. A totally-enclosed,
mechanically-ventilated hog finishing building was built in 1967 on the
property about 100 m (325 ft) southwest and across the road from the Wardens'
home. The building housed about 500 hogs on a partially-slotted floor,
121
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with a liquid manure pit below the floor. Manure pumped from the pit was
spread on the Sinning farm.
Having heard the testimony, the jury failed to reach a verdict and was dis-
missed.
A post-trial agreement between the two parties was reached on November
1970. The Sinnings agreed to clean and fill the pit so that it could
not be used to store animal waste, and further agreed that no confinement
type of livestock raising would be conducted on their 65 ha (160 acre)
farm within 0.8 km (0.5 mile) of the Warden home so long as the Wardens
maintained a residence on their existing farm.
This agreement by the Sinnings is binding also on their heirs, successors
and assignors. However, it does not prevent the S innings from using the
hog finishing building for purposes other than for the confinement of live-
stock or poultry or prevent them from the reasonable feeding of hogs,
cattle, or other livestock on any part of their property in any ordinary
manner other than by confinement.
Reference: Warden versus Sinning, Civil No. 30403 (Iowa Dist. Cr., Mar-
shall Co., May 25, 1970).
Winnebago Co. versus Fluegel (1970).
This case was heard by a judge in the Circuit Court, Winnebago County, 111.,
during 1969. Plaintiffs included the County of Winnebago and eight inter-
vening plaintiffs who were owners of property in close proximity (usually
less than 1.6 km (1.0 mile) to the property owned by the defendant, David
A. Fluegel.
A request for injunction was tried on two counts: (a) that the use of the
Fluegel property as a cattle feedlot was unlawful since it was contrary to
the zoning ordinance, and (b) that the cattle feedlot was both a public
and private nuisance because of odors, flies, other insects, bacteria in
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the air and nitrates in the groundwater that existed because of the feed-
lot operation.
The Fluegel property was located in an area that had been classified as
an "agricultural district" in 1942. Fluegel purchased the 10 ha (24 acre)
property in 1969 and proceeded to construct a commercial feedlot. The in-
tention was to construct a circular, funnel-shaped feedlot area on about
1.6 ha (4.0 acres). The circular, concrete-surfaced area would be divided
into 12 pie-shaped pens, with all pen surfaces sloping toward the center
of the circle. A shed was to be constructed in each pen. The completed
feedlot was planned to confine about 2,800 head.
The circular feedlot area was graded from property boundary to property
boundary across the narrower width of the land tract. A portion of the
area was concrete surfaced and sloped to drain to a sump in the center
of the circle. The sump drained to an earthen pit through a corrugated
metal pipe. Accumulated storm runoff was pumped from the pit and trucked
off the Fluegel property on at least one occasion; 1,400 cattle were placed
on the half-circle. The manure disposal plan was to truck the solid ma-
nure to a Wisconsin-based composting operation.
The previous owner of the land tract was a cattle feeder. A silo, hay shed,
cattle shed, and some cattle lots existed on the property when Fluegel
purchased it. Testimony indicated the previous owner had finished as many
as 400 cattle at one time.
Having heard the testimony, the Court found that the defendant was operat-
ing a commercial cattle feedlot in an Agricultural Use District, which
feedlot was not a stock farm, a domestic animal-breeding operation, or a
use commonly classed as agricultural, but was found to be a stockyard or
a use substantially similar to that of a stockyard as defined under Indus-
trial Zoning. Therefore, the defendant was found in violation of the zon-
ing ordinance.
The decree further found the feedlot to be a public nuisance because of
the imminent danger of contaminating groundwater, of actual pollution of
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surface water which escaped to nearby properties, of the existence of
offensive odors with no effective means to control or abate the odors,
and of substantially contributing to the fly population. The feedlot
was found a private nuisance also. The defendant was permanently enjoin-
ed from using the premises as a cattle feedlot after March 1, 1970. An
appeal was not perfected.
Reference: Winnebago Co. versus Fluegel, Chancery No. G-19425 (111.
Cir. Ct., Winnebago Co., Jan. 31, 1970).
Bower versus Hog Builders, Inc. (1970).
This was a civil action to recover damages and seeking an injunction be-
cause of a private nuisance. The case was heard by a jury in the District
Court, Platte County, Missouri, during 1969.
The plaintiffs were Mr. and Mrs. Glenn Bower and Mr. and Mrs. Frank Bower.
The Bower families live on adjacent farms of 23 and 22 ha (58 and 55 acres).
They had lived on their farms for 20 years or longer.
Hog Builders, Inc., the defendant, purchased a 56 ha (139 acre) tract across
the road north from the Glenn Bower property in 1965 and constructed facili-
ties for producing hog breeding stock. Eleven hog buildings with a com-
bined capacity of about 3,800 head were constructed in 1965 and 1966. Open
lots for hog confinement on the HBI property covered about 12 ha (30 acres)
All buildings were totally enclosed and mechanically ventilated with par-
tially-slotted floors over 1.2 m (4.0 ft) deep liquid manure pits. Pit con-
tents were emptied into anaerobic lagoons. Eight lagoons, with a combined
surface area of about two ha (five acres) were constructed between 1965
and 1969. Lagoons were enlarged or added as needed to store from three to
four years' manure production.
Plaintiffs' testimony indicated that some lagoon overflow or release of
lagoon contents with subsequent flow across the Frank and Glenn Bower
124
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properties occurred on several occasions. On one occasion, a dislodged
plug on one lagoon drainpipe permitted a large volume of lagoon-stored
waste to flow across the Glenn Bower property, through his stock watering
pond, and into a creek. Conservation Agent Paul Tichnor testified that
he observed dead fish in both pond and creek on different occasions.
Runoff from about 4.9 ha (12 acres) of hog lot area drained across the Glenn
Bower property and through the larger of Glenn Bower's two ponds accord-
ing to the natural flow of water. However, eroded soil and manure from
the hog lot filled the road ditch below the lot so that the road was over-
topped by runoff water. This permitted hog lot drainage to flow into
the smaller, second pond on the Glenn Bower property and near the vicinity
of his shallow, house well.
The Glenn Bower home was located about 250 m (800 ft) from the closest an-
aerobic lagoon and a somewhat lesser distance from the hog lot. The Frank
Bower residence was located a greater distance from these odor sources.
Both Bower families testified as to how obnoxious odors from the HBI pro-
perty affected the uses and values of their properties.
According to wind direction frequencies, odor would be transported from
the HBI property toward the Bower properties from 16 to 31 percent of the
time, varying from month to month based on an evaluation of Kansas City
weather data made by an expert witness for the plaintiffs.
Having heard the evidence submitted during the proceedings, the Court
awarded $46,200 in actual damages and $90,000 in punitive damages to the
Bower families. The greater amount went to the Glenn Bower family who
suffered the greater damage. The presiding judge had excluded an injunc-
tion as a possible choice.
The decision was appealed. After reviewing the case, the Supreme Court
of Missouri upheld the District Court's decision in December 1970.
Reference: Bower versus Hog Builders, Inc. 461 S. W. 2d 784 (Mo. 1970).
125
ftU-S. GOVERNMENT PRINTING OFFICE: 1974 546-319/404 1-3
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
. REPORT NO.
EPA-660/2-7^-023
3. RECIPIENT'S ACCESSION>NO.
4. TITLE AND SUBTITLE
ODORS FROM CONFINED LIVESTOCK PRODUCTION
5. REPORT DATE
April 197*1
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
J. Ronald Miner
8. PERFORMING ORGANIZATION REPORT NO.
fl. PERFORMING ORG \NIZATION NAME AND ADDRESS
Agricultural Engineering Department
Oregon State University
Corvallis, Oregon 97331
10. PROGRAM ELEMENT NO.
1BB039
11. CONTRACT/GRANT NO.
R802009-01
12. SPONSORING AGENCY NAME AND ADDRESS
U. S. Environmental Protection Agency
Washington, D.C. 20460
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
16. SUPPLEMENTARY NOTES
16. ABSTRACT
Current livestock production techniques result in the generation of odors which have
become a source of conflict between livestock producers and society. The odorous
gases responsible for the nuisance are principally low molecular weight compounds re-
leased during anaerobic decomposition of manure. Manure management systems which con-
trol or modify this decomposition offer the greatest potential for odor control.
Research to identify the chemical compounds present in odorous air from animal waste
degradation has yielded about 45 compounds to date. The amines, mercaptans, organic
acids and heterocyclic nitrogen compounds are generally regarded as being of greatest
importance. Among the techniques for odor control are: (a) site selection away from
populated areas and where adequate drainage exists, (b) maintain the animal areas as
dry as possible and prevent the animals from becoming manure covered, (c) select man-
ure handling systems which utilize aerobic environments for manure storage, (d) main-
tain an orderly operation free of accumulated manure and runoff water, (e) practice
prompt disposal of dead animals and (f) use odor control chemicals when short term
odor control is necessary, such as when manure storage tank content! mu«t be field
spread.
(Miner - Oregon State University)
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
*0dor, livestock, *Legal aspects, Cattle,
Hogs, Poultry, Hydrogen aulfide, Ammonia
*01faction, *ammonia de-
sorption, *Livestock
manure, *Manure, Odor
control
05A
05C
05D
18. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (This Report J
21. NO. OF PAGES
135
20. SECURITY CLASS (This page)
22. PRICE
EPA Form 2220-1 (»-73)
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