EPA-600/2-76-190
September 1976
Environmental Protection Technology Series
DESIGN PARAMETERS FOR
ANIMAL WASTE TREATMENT SYSTEMS-
NITROGEN CONTROL
Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Athens, Georgia 30601
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into five series. These five broad
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 fyjonitoring
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, equipment, 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.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
-------
EPA-600/2-76-190
September 1976
DESIGN PARAMETERS FOR ANIMAL WASTE TREATMENT SYSTEMS -
NITROGEN CONTROL
by
R. C. Loehr
T. B. S. Prakasam
E. G. Srinath
T. W. Scott
T. W. Bateman
Cornell University
Ithaca, New York 14853
EPA Project Number S800767
Project Officer
Lee A. Mulkey
Technology Development and Applications Branch
Environmental Research Laboratory
Athens, Georgia 30601
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
ENVIRONMENTAL RESEARCH LABORATORY
ATHENS, GEORGIA 30601
-------
DISCLAIMER
This report has been reviewed by the Athens Environmental Research
Laboratory, US Environmental Protection Agency, and approved for
publication. Approval does not signify that the contents necessarily
reflect the views and policies of the US Environmental Protection Agency,
nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
11
-------
ABSTRACT
Laboratory, pilot plant and field scale studies were conducted to eval-
uate design parameters for treating animal wastes and achieve nitrogen
control. The studies indicated that nitrogen control can be achieved
in a single aeration unit. By proper manipulation of the microbial
activity, nitrogen removals in the range of 30 to 90 percent of the
total input nitrogen to the system could be achieved.
Depending upon the phase of operation, nitrogen losses occurring in the
system were either due to ammonia volatilization or denitrification of
the oxidized nitrogen compounds. Most of the nitrogen losses during the
start-up phase were due to ammonia volatilization. Nitrogen losses occur-
ring during the nitrification phase were attributed to denitrification
occurring in the microbial floe due to localized anaerobic conditions
in or around microbial floe.
The feasibility of achieving varying amounts of nitrogen using a sequen-
tial nitrification-denitrification mode of operation was demonstrated in
a pilot plant oxidation ditch treating poultry waste.
Agronomic field studies conducted indicated that nitrogen from the oxi-
dation ditch-stabilized poultry manure was as available to plants as
nitrogen from fresh poultry manure. Nitrate concentrations in soils
increased with increasing rates of manure application. At a given rate
in
-------
of manure application, nitrate levels in soils were higher under corn
than under grasses. Grasses responded favorably to application of
manurial nitrogen in the range of 100-170 Kg N/ha. There were seasonal
variations in the responses of grasses and corn to manurial nitrogen.
During spring, manure application rates beyond 224 Kg N/ha were not
beneficial to corn and could cause damage to crops as well as the
environment.
Based on experimental evidence on plant growth, corn and grasses, it
was recommended (1) that in the spring season, poultry manure could be
applied on either grass or corn, and (2) that the application in the
fall season should be on grass.
This report was submitted in fulfillment of Project Number S800767
by Cornell University under the sponsorship of the Environmental Protec-
tion Agency. Work was completed as of December 31, 1974.
IV
-------
CONTENTS
PAGE
I Conclusions 1
II Project Need and Objectives 4
III Experimental Studies on Waste Stabilization, 7
Land Disposal, and Nitrogen Control
IV Results of the Engineering Studies on 32
Nitrogen Control
V Results of Studies on Land Application of 82
Poultry Wastes
VI Discussion of Experimental Results 105
VII Design Examples 130
VIII References 135
IX Appendix 138
-------
LIST OF FIGURES
FIGURE TITLE PAGE
1 Effect of total solids concentration on a in a 18
mixed liquor (Calhoun, 1974)
2a Mode of oxidation ditch operation I 20
b Mode of oxidation ditch operation II 21
c Mode of oxidation ditch operation III 22
d Mode of oxidation ditch operation IV 23
3 Nitrogen applied over a 4-year period as poultry 28
manure or chemical fertilizer. Poultry waste
residue study, 1971-1974
4 Changes in the oxygen uptake rate during waste 33
stabilization
5a Changes in pH during stabilization and nitri- 34
fication
b Changes in concentration of nitrates during 34
stabilization and nitrification
6 Total nitrogen contents of the wastes in the 37
different systems during stabilization
7 Cumulative oxygen uptake over time 39
8 Cumulative oxygen uptake in the different systems 46
during stabilization
VI
-------
LIST OF FIGURES continued
FIGURES TITLE PAGE
9 TKN contents of the wastes in the different systems 47
during stabilization
10 Total nitrogen profile of the influent and 60
effluent of settling tank - June 6 - September
13, 1973
11 Oxidized nitrogen profiles of influent and effluent 61
of settling tank - June 6 - September 13, 1973
12 Profile of NOo-N in ODML - operational mode IV 65
13 Nitrogen input and the quantity accounted for in 68
the ditch
14 Actual quantity vs. nitrogen estimates 73
15 Effect of operation of oxidation ditch on 74
nitrification
16 Fluctuations in nitrogen contents of mixed liquor 76
in oxidation ditch #1 at Manorcrest Farms
17 Fluctuations in nitrogen contents of mixed liquor 77
in oxidation ditch #2 at Manorcrest Farms
18 Expected and observed total nitrogen contents of 78
mixed liquor in oxidation ditch #1 at Manorcrest
Farms
19 Expected and observed total nitrogen contents of 79
mixed liquor in oxidation ditch #2 at Manorcrest
Farms
Vll
-------
LIST OF FIGURES continued
FIGURE TITLE PAGE
20 Average growing season N03 level in the surface 83
soil 0-23 cm as influenced by several rates of
spring applied ODML on corn and grass, 1973.
Average of four studies
21 Average growing season N03 levels in the subsoil, 84
24-46 cm, as influenced by several rates of spring
applied ODML on corn and grass, 1973. Average of
four studies
22 N03 level in the soil according to month of growing 86
season and crop grown. Average of four studies
23 Average growing season N03 + NH^ in the soil as 87
influenced by the rate, form and time of poultry
manure application. Poultry farm runoff study
24 Average growing season N03 + NO. in the soil as 88
influenced by the rate, form and time of applica-
tion of poultry wastes. Aurora Farm runoff study,
1973
25 Relationship of nitrogen uptake in grain and stover 93
to dry matter produced. Aurora Farm runoff study,
1973
26 Relationship of nitrogen uptake in grain and stover 94
to dry matter produced. Aurora Farm runoff study,
1973
Vlll
-------
LIST OF FIGURES continued
FIGURE TITLE PAGE
27 Average NO- + NH. in the soil during 1973 growing 96
season as influenced by rate of ODML and commercial
fertilizer. Aurora Farm residue study, 1973
28 Two year average yield (1972 and 1973) on poultry 97
waste residue study. Aurora, New York
29 1974 yields from poultry waste residue study. 98
Aurora, New York
30 Relationship of nitrogen uptake in grain and 99
stover to dry matter produced. Poultry waste
residue study. Aurora, New York, 1973
31 The effect of source, rate and time of applica- 101
tion of poultry manure and commercial fertilizer
on the yield of orchard grass (2 cuttings)
L.S.D.® .05 = 1255. Aurora Farm grass study, 1973
32 The effect of source, rate and time of applica- 102
tion of poultry manure and commercial fertilizer
on the yield of orchard grass (2 cuttings)
L.S.D.@ .05 = 1939. Aurora Farm grass study, 1973
33 Relationship of nitrogen uptake in orchard grass 103
to dry matter produced. Aurora Farm grass study,
1973
IX
-------
LIST OF FIGURES continued
FIGURES TITLE PAGE.
34 Relationship of nitrogen uptake in bromegrass 104
to dry matter produced. Aurora Farm grass
study, 1973
35 Aeration period and nitrogen losses in an 110
oxidation ditch
36 Quantitative effect of treatment objectives 119
on aeration requirements
37 Nitrification-dentrification of cyclic rotor 121
operation (Prakasam ejt a]_., 1974)
38 Relationship between nitrogen removal and 124
rotor design requirements
-------
LIST OF TABLES
TABLE TITLE PAGE
1 Production of Layers and Estimates of the Nitrogen, 8
Total Solids and COD Contents of the Manures from
the Egg Production Facilities
2 Some Components of Oxidation Ditch Manure Used as a 27
Source of N for Field Studies, 1973, Parts per Million
3 Components of Nitrifying Waste Suspensions and the 30
Initial Conditions in the Laboratory-Scale Nitri-
fication Systems
4 Nitrogen Losses Due to Ammonia Desorption and Deni- 36
trification in the Stabilization Systems of Trial #1
5 Nitrogen Losses Due to Ammonia Desorption and Deni- 38
trification in the Stabilization Systems of Trial #2
6 Nitrogen Losses Due to Ammonia Desorption and Deni- 41
trification in the Stabilization Systems of Trial #3
7 Nitrogen Losses Due to Ammonia Desorption and Deni- 42
trification in the Stabilization Systems of Trial #4
8 Nitrogen Losses Due to Ammonia Desorption and Deni- 43
trification in the Stabilization Systems of Trial #5
9 Nitrogen Losses Due to Ammonia Desorption and Deni- 44
trification in the Stabilization Systems of Trial #6
XI
-------
LIST OF TABLES continued
TABLE TITLE PAGE
lOa Cumulative Oxygen Uptake (COU), Nitrogen and 48
COD Removals Observed During Stabilization of
Wastes in the Different Systems of Trial #7
b Effect of Equilibrium Dissolved Oxygen Concen- 49
tration and Oxygen Uptake Rate of Nitrogen Loss
11 Operational Parameters of Oxidation Ditch - 50
Mode of Operation I
12 Nitrogen Balance - Mode of Operation I 51
13 Continuous Flow Operation of the Oxidation Ditch 52
with Solids Control and with Intermittent "In Situ"
Denitrification of the Mixed Liquor
14 Nitrogen Losses During Different Modes of Opera- 53
ation with Solids Control and with Intermittent
"In Situ" Denitrification
15 Nitrogen Loss in Oxidation Ditch System - 56
Operational Mode II
16 Operational Parameters of Oxidation Ditch - 57
Operational Mode III
17 Total Nitrogen Balance in Operational Mode III 58
18 Nitrogen Balance in an Oxidation Ditch - 63
Operational Mode IV (Rotor on for 16 hr/day)
xn
-------
LIST OF TABLES continued
TABLE TITLE PAGE
19 Nitrogen Balance in an Oxidation Ditch - 64
Operational Mode IV (Rotor on for 12 hr/day)
20 Inputs to the Oxidation Ditches, Mean Concentra- 70
tions of Ammoniacal Nitrogen, pH, and Temperature
of ODML at the Houghton Farms
21 Characteristics of the Mixed Liquor from the 81
Oxidation Ditch at the Mink Farm
22 Water, Sediment and Certain Nutrients Lost in 90
Runoff - Aurora Farm Runoff Study, 1973-1974
23 Water, Sediment and Certain Nutrients Lost in 92
Runoff - Poultry Farm Runoff Study, 1972-1973
24 Summary of Expected Nitrogen Losses in Different 111
Modes of Oxidation Ditch Operation
25 COD Losses in an Oxidation Ditch During Various 112
Modes of Operation
26 Capital and Operating Costs for Oxidation Ditches 125
at the Houghton Poultry Farm
27 Oxygen Requirement, Power and Cost Data for the 127
Oxidation Ditch Systems at Manorcrest Farms, Inc.,
Camillus, New York
xm
-------
ACKNOWLEDGEMENTS
This research was supported by the Environmental Protection Agency under
project number S800767 and by the College of Agriculture and Life Sciences,
Cornell University. The guidance of Mr. Lee Mulkey, Environmental Protec-
tion Agency, Athens, Georgia, who served as the project officer, is
gratefully acknowledged.
The project is a multidisciplinary effort of the Departments of Agricultural
Engineering and Agronomy of the College of Agriculture and Life Sciences
at Cornell University. Drs. R. C. Loehr and P. J. Zwerman are the project
directors.
The principal investigators associated with the project are: Drs. T.B.S.
Prakasam, E.G. Srinath, T. Bateman and T. Scott.
The help of J. H. Martin, Jr., A. C. Anthonisen and H. T. Grewling, and
the support of Dr. M. J. Wright, Chairman, Department of Agronomy are
gratefully acknowledged. Technical assistance was provided by Y. D. Joo
and R. Jones.
The help of R. J, Krizek, J. F. Gerling, and E. Callinan in the preparation
of the figures is gratefully appreciated.
The patience and skill of Arlene Learn, Diane LaLonde, Sally Gray, and
Judy Eastburn in typing the report are most sincerely appreciated.
XIV
-------
SECTION I
CONCLUSIONS
1. Aerobic systems can be designed to treat animal wastes and achieve COD,
solids, odor, and nitrogen control.
2. Nitrogen control can be achieved in a single aeration unit by manipu-
lating the microbial processes of nitrification and denitrification. Such
control is compatible with the normal operation of the aeration unit and
the continuous addition of manure to the unit.
3. The aerobic systems can be manipulated to achieve nitrogen removal in
the range of 30 to 90 percent of the total input of TKN into the system
depending upon the nitrogen management objectives of the animal production
unit. Various modes of operation can be used to achieve the desired objec-
tives of nitrogen control.
4. Nitrogen losses occur in animal waste treatment systems even under
aerobic conditions. Variations in the extent of nitrogen losses are re-
lated to the total oxygen demand exerted.
5. The nitrogen losses occurring under aerobic conditions are the result
of either ammonia volatilization or denitrification of the oxidized nitrogen
compounds depending on the phase of operation of the treatment system.
Nitrogen losses due to ammonia volatilization are maximum during the
-------
start-up-phase of a treatment system. Denitrification losses taking place
during the aerobic phase are postulated as due to the localized anaerobic
conditions in or around the microbial floe.
6. Using a mass balance approach, predictive relationships were developed
to calculate the nitrogen losses obtainable in the aerobic systems.
7. The nitrifying microorganisms can withstand severe environmental stresses
such as high concentrations of undissociated ammonia and very low concentra-
tions of dissolved oxygen or even anaerobic conditions for long periods of
time. In view of this, an aerobic animal waste stabilization unit can be
operated using a cyclical nitrification-denitrification approach to
achieve nitrogen control.
8. If the concentration of solids, COD and nitrogen content of the waste
is known, it is possible to estimate the quantities of oxygen needed to
achieve odor control and nitrogen removal. The size of treatment units
and the lengths of rotor needed for operating the oxidation ditch systems
can be calculated.
9. Nitrate concentrations in soils increase with increasing rates of poul-
try manure application. Concentrations of nitrates are about twice as high
in surface soils as in subsoils for a given rate of manure application.
10. For a given rate of manure application, soil nitrate levels were higher
under corn than under grass. Poultry manure applied in the spring for corn
should not exceed rates that supply more than 224 kg N/ha. Rates above this
level can supply more nitrates than will be taken up by corn. These excess
nitrates are then subject to leaching beyond the rooting depths of corn.
-------
11. There were no differences between fresh poultry manure or oxidation
ditch mixed liquor from an oxidation unit treating poultry manure on the
nitrate concentration in soils.
12. The manure source did not result in differences in runoff water,
nitrates, ammonium, total soluble phosphorus or soil sediments carried
off by the runoff water.
13. Corn grain yields responded significantly to poultry manure appli-
cations up to 224 kg N/ha.
14. Although it is difficult to calculate mineralization rates, estimates
are that 50% of the nitrogen in poultry manure is available the first
year. Much smaller amounts are available in succeeding years.
15. Grasses responded favorably to poultry manure at application rates
in the range of 100-170 kg N/ha.
16. Poultry manure applied in the fall should be on grass. Spring
applications can be on grass or corn.
17. Nitrogen from oxidation ditch manure was as available to plants as
nitrogen from fresh manure.
-------
SECTION II
PROJECT NEED AND OBJECTIVES
PROJECT NEED
The changes in agricultural practices, such as mechanization and animal
production in close confinement significantly have increased the effici-
ency of such production. Such changes at the same time also have created
more difficult waste management problems. The satisfactory disposal of
animal wastes from these operations is the key to both successful animal
production and environmental protection. The close proximity of some of
these animal production units to towns, and a desire to protect the quality
of water resources have resulted in a greater awareness of the environmental
problems caused by manure disposal from these units.
Disposal of poultry wastes presents a particularly difficult problem.
They contain high concentrations of organic matter which can easily under-
go putrefactive changes. The proper management of manure is essential
for the success of the poultry operations and protection of the environment.
In view of the 1972 amendment to the Federal Water Pollution Control Act,
controlled land disposal of wastes assumes greater importance in the schemes
of waste management. Since land is the ultimate receptacle for the wastes,
the extent of waste stabilization required before such disposal is not
comparable to those needed in municipal sewage treatment works. A high
degree of BOD or COD removal, comparable to secondary effluent quality,
-------
is not needed. The objectives of waste stabilization will be based on
factors such as odor control and nutrient management.
The disposal of the wastes on land may result in subsequent runoff causing
surface water pollution and contamination of groundwater due to subsurface
percolation of nitrogen in the wastes. The disposal of poultry wastes on
land requires the design of feasible waste stabilization systems that will
minimize the risks of causing air pollution, soil contamination, and surface
and groundwater pollution problems. When adequate land is available, it is
desirable to utilize the manurial nitrogen for crop production and to conserve
as much nitrogen as possible. In situations where integration of wastes
with soil for the benefit of crop production is not possible, there is need
to decrease the nitrogen content to make the stabilized waste suitable for
disposal on the available land.
To devise approaches for the proper disposal of animal wastes on the land,
data are needed on the stabilization required to achieve varying degrees of
nitrogen removal without sacrificing other environmental protection objec-
tives such as odor control and BOD and COD removal. Earlier studies (4, 5,
20) on animal waste management have shown that by operating an in-house
oxidation ditch system, the manures could be stabilized and also render the
animal confinement area almost free of odors. The studies also indicated
that by "in situ" denitrification of the nitrified liquor in the oxidation
ditch, the nitrogen content of the wastes could be significantly decreased.
However, the available information on the methods of operation of oxidation
ditch systems was not sufficient to develop guidelines to operate the oxi-
dation ditch system to achieve different degrees of nitrogen removal. A
knowledge of such modes of operation of the oxidation ditch system is essen-
tial to broaden the spectrum of alternatives available for designing accep-
table animal waste management systems.
-------
PROJECT OBJECTIVES
The specific objectives of this study were to: (a) develop design criteria
to achieve nitrogen and odor control in animal waste stabilization systems;
(b) demonstrate the feasibility of achieving nitrogen control by using oxi-
dation ditches; (c) determine the rate, form and time of manure application
permissible without causing pollution of surface runoff and groundwaters;
and (d) determine the optimum rate, form and time of application for best
crop response.
The main emphasis of the project has been to demonstrate the feasibility
of achieving nitrogen control without sacrificing other environmental
objectives such as odor elimination, waste stabilization, and nutrient
availability for crop production. The develpoment of design criteria to
achieve these objectives is important for designing and operating waste
stabilization systems to meet varying waste management objectives.
-------
SECTION III
EXPERIMENTAL STUDIES ON WASTE STABILIZATION,
LAND DISPOSAL AND NITROGEN CONTROL
INTRODUCTION
Until recently agriculture was not considered a serious source of environ-
mental pollution due to the diverse nature of agricultural activities and
comparatively small size of the production units. With the changing prac-
tices in animal production, the sizes of operations are larger and have
contributed to the marked increase in agricultural output. At the same
time these production practices have altered the traditional complimen-
tary relationship between livestock and crop production whereby the live-
stock wastes were used to fertilize and amend the croplands. There is
an increasing need for the disposal of large quantities of manures pro-
duced in concentrated livestock operations. As an example of the trends
in livestock industry, estimates of layer production and the nitrogen,
total solids and COD content of the manures generated by egg production
units are shown in Table 1.
The effluent guidelines for feedlot industry (3) indicate that the wastes
should not be discharged into watercourses. Thus land disposal of animal
wastes continue to be an important component of any animal waste manage-
ment scheme. Due to the recent economic changes, and possible shortages
of chemical fertilizers, animal wastes are being viewed with interest
-------
Table 1. PRODUCTION OF LAYERS AND ESTIMATES OF THE
NITROGEN, TOTAL SOLIDS AND COD CONTENT OF
THE MANURES FROM THE EGG PRODUCTION FACILITIES**
Year
1960
1965
1970
1980
2000
*
**
Layers
(millions)
295
301
313
348
446
based on references
AQtimatoc hacoH nn 1
Nitrogen
(million Ibs)
597.7
609.8
634.1
705.0
903.6
1 and 2
hho nhcaywa ti rmc at ni
Total Solids
(million Ibs)
7115.1
7259.8
7549.2
8393.4
10757.0
iv 1 ahnva tnvv that
COD***
(million Ibs)
3557.6
3629.9
3774.6
4196.7
5378.5
the nuantitv
***
of total solids and nitrogen content of the excreta is 30 and 2.5 gms
per day per bird
COD estimates are based on the approximation that about 50% of the
total solids is COD
as alternate sources of crop nutrients. When adequate agricultural land is
available, it is preferable to integrate animal waste disposal with crop pro-
duction and thereby take advantage of the fertilizer value of the wastes.
Difficulties arise when either local conditions are not favorable, or
adequate land is not available for disposal. Excessive amounts of manure
on land can alter the physical properties of the soil,and the oxygen demand
exerted by organic matter can influence the microflora of the soil. Uncon-
trolled spreading of manure on land also increases the risks of contamina-
tion of surface waters by runoff and groundwater by seepage.
The contaminants reaching the surface waters by runoff from lands on which
manure is disposed include among other things, (a) organic matter;
-------
(b) nitrogen compounds; and (c) phosphorus compounds. Phosphates present
in the wastes are immobilized by reactive iron and aluminum present in the
soil, and the organic matter is adsorbed on the soil particles. Nitrifi-
cation of NH* occurs in soil and water environments and in aerobic treat-
^ +
ment systems. Unlike NH^ , nitrites and nitrates are not retained by clay
particles in the soil. The infiltration of nitrate results in contamination
of groundwater. If the concentration of nitrates in the water is high, then
the water is unfit for potable purposes. Oxidation of NH* in the receiving
waters exerts a demand for oxygen. Therefore, the application rates of
nitrogen to the land can be a controlling factor whether the land is used
for either growing crops or for disposal to meet the objectives of environ-
mental protection. These objectives include odor control, waste stabili-
zation and nutrient management.
Unless the wastes are properly stabilized and managed, land disposal of
poultry wastes, especially in situations where adequate land is not avail-
able, could lead to environmental damage. In this context, the problem of
detrimental effects on the environment due to manurial nitrogen is of parti-
cular concern. The available technology for nitrogen management in animal
wastes is inadequate. Therefore, the disposal of animal wastes on land
presents a challenge for the environmental engineers to design feasible
stabilization and disposal systems that will minimize the risks of air and
water pollution.
An understanding of the effect of different factors influencing the aerobic
stabilization of wastes is important to the design and operation of stabili-
zation systems for nitrogen and odor control. Microorganisms present in the
waste stabilization systems utilize the carbon, nitrogen, and phosphorus
compounds for their metabolic activities. The resulting transformations
account for the changes in the characteristics of the waste, especially in
the total solids, COD, nitrogen and phosphorus contents. The ultimate
products of oxidation of carbonaceous matter are C02 and water. The decreases
-------
in total solids and COD occurring in aerobic stabilization systems are
due to microbiai transformations resulting in release of C0?.
Nitrogen in fresh animal excreta is essentially in the organic form as
proteins, urea, or uric acid (mammals excrete urea, birds excrete uric acid).
Transformations occurring in waste stabilization systems can result in dif-
ferent forms of nitrogen in the stabilized waste. The exact sequence of
changes is influenced by environmental conditions. The first step in such
changes during stabilization of animal wastes is ammonification of organic
nitrogen:
Ammonification
Organic nitrogen *• NH-- -»• NH4 + OH" (1)
(heterotrophs)
Ammonification of organic nitrogen is accompanied by an increase in pH. If
the ammonium concentration and pH are sufficiently high, ammonia volatiliza-
tion can occur.
Under aerobic conditions, ammonium nitrogen can be microbially oxidized to
nitrate by two groups of autotrophic microorganisms, viz; Nitrosomonas and
Nitrobacter. This process of oxidation of NH« to N0g~ is termed as
nitrification.
Nitrosomonas
NH4 + 1.5 02 -*• NO" + 2H + H20 (2)
Nitrobacter
N02 + 0.5 02 >• N0~ (3)
Under anaerobic conditions, the nitrite and nitrate can be reduced to nitrogen
gas (N2) or gaseous nitrogen oxides (N20 or NO) by denitrifying organisms.
The rate of oxygen utilization in aerobic stabilization system can be
expressed as a function of the rate of removal of organic matter and the rate
10
-------
of endogenous respiration of the microbial mass. The following general
equation describes the rate of oxygen utilization for oxidation of car-
bonaceous matter:
{£ = a.(§) +b.c.X (4)
where
dt = the rate of oxygen utilization,
•T = the rate of substrate utilization
a = the coefficient used to convert substrate
units to oxygen units
b = microbial decay coefficient
c = coefficient used to convert cell mass units
to oxygen units
x = the microbial cell concentration
If nitrification is the objective of the stabilization, oxygen requirements
are increased
d[NHt] d[N09]
dt = a'( dF + b'c-X + 3'43 dt
d[NHT] dNO"
where —-TL— and —rr— are respectively, the rates of
Q U Q u
oxidation of ammonia to nitrite and nitrite to nitrate.
Earlier, studies (4,5) conducted by the investigators of this project have
indicated (i) that significant removals of nitrogen could be achieved by
nitrification followed by denitrification; (ii) that nitrogen losses due
to denitrification could occur under seemingly aerobic conditions;
11
-------
(iii) that effective odor control could be achieved by stabilization of wastes
in an oxidation ditch; (iv) that oxygen requirements for treatment with
control and partial stabilization will be lower than for a system designed
to achieve nitrification; and (v) that large concentrations of dissolved
and suspended solids may hamper rates of oxygen transfer to the microorganisms
during aerobic stabilization.
Studies (5) on land application and crop response to treated poultry manure
indicated that (a) residual benefits from poultry manure to corn grain yields
were evident the year following application; (b) the mineralization rate of
nitrogen in poultry manure is about 50% as measured by crop response; (c) a
comparison of the mixed liquor from an oxidation ditch treating poultry manure
with raw poultry manure applied to prepared corn land in the spring resulted
in no significant runoff losses of soluble phosphorus, nitrate, ammonium, soil
losses or water runoff; and (d) oxidation ditch stabilized manure applied in
the spring was a superior nitrogen source on orchard grass when compared with
fresh poultry manure.
To develop design criteria for waste stabilization systems that integrate
nitrogen control, additional experimental evidence has been collected on
(i) the factors influencing nitrogen losses during aerobic biological stabi-
lization of animal wastes; (ii) the effect of different modes of operation of
a pilot plant scale oxidation ditch on nitrogen removal from the wastes;
(iii) the performance of full scale waste stabilization systems at two poultry
production operations; and (iv) the performance of an oxidation ditch system
installed to control odors in an experimental mink farm.
Additional experimental evidence was collected on the evaluation of field
application of stabilized poultry wastes from an oxidation ditch and raw or
untreated sources by (a) measuring corn, bromegrass and orchard grass res-
ponse to several manure sources, (b) measuring runoff losses of nitrate,
ammonium, soluble phosphorus and soil from treated plots; and (c) measurement
of residual effects of applied manure.
12
-------
MATERIALS AND METHODS
Laboratory Studies
A series of studies were conducted to obtain detailed information on the
factors affecting nitrogen control in aerobic systems. Details of the
equipment, approaches, and methods used in these studies are outlined in
this section. All the laboratory studies were conducted at room tempera-
ture (20°C - 23°C).
The required concentrations of the wastes were made by suspending the
requisite amount of poultry manure in distilled water. The mixture was
blended in a Waring blender and filtered through a single layer of cheese-
cloth to remove large particulate matter. The material retained on the
cheesecloth was washed with distilled water to recover most of the soluble
matter. The filtered suspensions were diluted to the required volume with
distilled water.
Different quantities of ODML and poultry manure suspensions in tap water
were aerated by placing Erlenmeyer flasks, containing the suspensions,
on a variable speed rotary shaker. Rotary shaking not only aerated the
samples but also provided adequate mixing of suspensions.
Analytical Methods
A mineral salts solution was used in certain experiments to resuspend centri-
fuged mixed liquor solids. The salt solution contained the following:
MgS04-7H20, 250 mg/1; FeS04-7H20, 10 mg/1; CaCl2'2H2Q, 10mg/l.
Mixed liquor from the pilot plant oxidation ditch was used in some labor-
atory experiments and is referred to in this report as ODML.
Total solids, volatile solids, and BOD were determined as described in
Standard Methods (6). COD was determined by a rapid method (7).
13
-------
Suspended solids were determined by filtering a known volume of the sample
through glass filter paper. The weight of the dry solids retained on the
filter paper was used as an estimate of the suspended solids. A considerable
length of time was generally taken for the filtration of the relatively
concentrated samples. In such situations, a part of the weight of the
suspended solids may have included some dissolved solids.
The pH of the sample was measured with a Corning pH meter.
Ammonium nitrogen, nitrite and nitrate nitrogen were determined by a steam
distillation procedure (8). N02-N was separately determined by a diazoti-
zation method (9), and its value was subtracted from the (N02+N03)-N value
obtained by the steam distillation method to obtain the value of N03~N.
Total Kjeldahl nitrogen (TKN) was determined by a micro-Kjeldahl method (10).
The concentration of dissolved oxygen in the samples was determined by using
a YSI model 54 oxygen meter. The sensing element was a membrane covered
polarographic probe which was compensated for temperature effects of both
the probe membrane permeability and solubility of oxygen in water.
Routine methods of analysis (11, 12) were employed to examine plant tissues,
manured and non-manured soils, soil leachate and runoff for the different
forms of nitrogen. Soil leachates and runoff were also examined for
orthophosphates and total soluble phosphates (12, 13, 14).
Storage of Samples
All the nitrogen analyses, COD, and BOD were performed on the samples rapidly
and without storage. N02-N and NO^-N analyses of samples stored with H,,SO,
were found to be unsatisfactory. In the determination of solids, it sometimes
was inconvenient to process all the samples in one day. On such occasions
the samples were refrigerated and determinations were made as soon as possible,
14
-------
Rate of Oxygen Transfer
Oxygen transfer rates of the aeration systems were determined in tap water
for the different operating conditions of this study. Dissolved oxygen in
the water was removed by adding 8 mg of sodium sulfite per mg of dissolved
oxygen to deplete the dissolved oxygen adding cobalt chloride (0.1 mg per
liter) as a catalyst. When the dissolved oxygen concentration reached
zero, aeration was started and the changes in the concentration of dis-
solved oxygen was recorded by using a Honeywell Electronic recorder in
conjunction with the oxygen meter. The oxygen transfer rate was computed
using the following equation:
f = KLa ^
where
K. a = oxygen transfer rate
d£
dt = change in dissolved oxygen with time
C = saturation concentration of dissolved oxygen
C. = concentration of dissolved oxygen at time t.
The rate of oxygen transfer into a microbiologically active mixed liquor
can be represented by the following modification of equation (6):
£ = K'La (C's - Ct) - Rr (7)
where
K'.a = oxygen transfer rate into the mixed liquor
saturation cc
mixed liquor
C1 = saturation concentration of dissolved oxygen in the
15
-------
C, - concentration of dissolved oxygen at time t
and R - oxygen uptake rate of the mixed liquor
When the microbiologically active mixed liquor exerting an oxygen demand
is being aerated and the system has reached a steady state with respect
to the concentration of dissolved oxygen, then dc/dt = 0, and
R
K,a = p V" (8>
L Cs - Ceq
where
C = the concentration of dissolved oxygen at the
steady state condition
To determine the concentration of dissolved oxygen at steady state condi-
tions, the probe was placed in the liquid that was being aerated. The
changes in the concentration of dissolved oxygen were followed.
After the system had reached a steady state with respect to dissolved oxygen,
the aeration was stopped and the profile of the changes in the concentration
of dissolved oxygen with time was recorded. The oxygen uptake rate was cal-
culated using the recorded data.
The value of the saturation concentration of dissolved oxygen in water at
different temperatures was obtained from the tables (6). The value of C
was corrected to actual atmospheric pressure by the following equation:
Cs (actual) = Cs (tabulation value) Atmospheric pressure (inches Hg)
The saturation concentration of dissolved oxygen in a mixed liquor (C1 ) can
be calculated by using the following equation:
16
-------
C (actual) = 3' C. (actual)
o o
The value of e for poultry wastes was assumed to equal one.
The experimental evidence collected at the AWML (Agricultural Waste Manage-
ment Laboratory, College of Agriculture and Life Sciences, Cornell University)
have indicated that the concentration of total solids in the ODML significantly
affect the oxygen transfer relationships (Fig. 1). In this study, the rela-
tionship between a and total solids content of the mixed liquor shown in
Fig. 1 was utilized to calculate the oxygen transfer rates in suspensions
of varying solids concentration.
Pilot Plant Oxidation Ditch Studies
The oxidation ditch at the Agricultural Waste Management Laboratory has been
operating and evaluted continuously since 1970. During the period of this
project it was operated at various solids concentrations. Nitrogen mass
balances were made and the nitrogen losses in the ditch were related to
the varying operating conditions.
The concentration of total solids in the oxidation ditch was varied by
altering the water input to the ditch. The operational control of the total
solids content necessitated the installation of an automatic overflow in
addition to control of water input to the ditch. The data collected in
this study included: rotor immersion depth, waste output, water input,
rates of oxygen uptake, temperature, COD, total and volatile solids, and
organic, ammonia, nitrite and nitrate nitrogen.
Solids concentrations were changed only after a suitable equilibrium period
was established. During the study, the immersion depth of the rotor was
increased whenever the concentration of dissolved oxygen in the mixed
liquor was close to zero. The reduction in dissolved oxygen concentration
17
-------
UJ
H-
CO
cr
UJ
00
II
0
X
Q_
1.41-
1.2
1.0
.8
.6
4
.2
~
"T
I
I
i
I
I
a = 1.36-.17 MLTS
I
I
3 4
TOTAL SOLIDS, %
a =.4
a D
Figure 1. Effect of total solids concentrations on a in a poultry waste
mixed liquor (Calhoun, 1974)
-------
occurred as a result of the decreased oxygen transfer capabilities of
the rotor as the solids concentration increased. Thus an equilibrium period
consisted of more than one sub-phase if the rotor immersion depth was changed.
Modes of operation - To evaluate nitrogen losses in the oxidation ditch, the
following modes of operation were studied: a) continuous rotor operation and
without intentional wasting of the mixed liquor; i.e., as an aerated holding
tank with continuous addition of wastes (Fig. 2a), b) maintenance of a solids
equilibrium condition by intentionally wasting some mixed liquor and sub-
jecting the remaining mixed liquor to intermittent denitrification (Fig. 2b),
c) maintenance of solids equilibrium and using a solids separation tank to
settle the mixed liquor suspended solids and to denitrify the recycled efflu-
ent (Fig. 2c), d) intermittent periods of rotor aeration which permitted
nitrification and denitrification. In this mode, the rotor was connected
via a time switch which controlled the time of operation of the rotor
(Fig. 2d). When the rotor was operating, aerobic conditions prevailed in
the mixed liquor and nitrification was sustained. When the rotor was off,
anoxic conditions resulted in the mixed liquor and denitrification occurred.
Studies With Other Oxidation Ditches
The technical feasibilities of the waste management principles were evaluated
and the managerial problems associated with the process were identified by
monitoring the waste stabilization facilities at (a) two commercial poultry
farms, and b) an experimental mink farm. The studies on the operation of
the oxidation ditch at the mink farm were mainly to verify the applicability
of pilot plant design and operation principles for poultry wastes to treat-
ment systems for other animal wastes. The following is a brief description
of these three facilities:
(a) A commercial 15,000 bird poultry operation owned by Mr. Charles Houghton,
a farmer. An oxidation ditch system had been installed to control odors.
19
-------
MODE OF OXIDATION DITCH OPERATION-I
WASTE
I
--ROTOR
AERATED HOLDING TANK
Figure 2a. Mode of oxidation ditch operation I.
-------
to
MODE OF OXIDATION DITCH OPERATION-H
I
WASTE
-- ROTOR
\ I
MIXED LIQUOR OVERFLOW (DISPOSAL)
CONTINUOUS FLOW OPERATION (SOLIDS CONTROL)
Figure 2b. Mode of oxidation ditch operation II.
-------
MODE OF OXIDATION DITCH OPERATION - HI
WASTE
I
ROTOR
bO
to
PUMP
T
SETTLING
TANK
RETURN
SUPERNATANT
EXCESS SLUDGE
(DISPOSAL)
SOLIDS EQUILIBRIUM WITH A SETTLING
TANK AND RECYCLING OF SUPERNATANT
Figure 2c. Mode of oxidation ditch operation III.
-------
to
CO
MODE OF OXIDATION DITCH OPERATION -32
I
WASTE
-=ROTOR
TO AC
TIME SWITCH
CURTAILED ROTOR OPERATION
Figure 2d. Mode of oxidation ditch operation IV.
-------
Personnel of Cornell provide technical assistance and monitoring of the
waste treatment system.
(b) A commercial 30,000 bird poultry operation at Camillus, New York,
owned by Manorcrest Farms. Two of the three poultry houses in this farm
are being utilized to demonstrate the performance of aeration systems to
stabilize poultry wastes. This demonstration is supported by an EPA grant-
EPA project number S800863. Cornell University personnel are in charge
of the engineering and analytical aspects of this project.
(c) A mink farm sponsored by the USDA in a cooperative program with Cornell
University. Advances made in fur animal husbandry have shown the economic
advantages resulting from raising mink in closed sheds with light and
temperature control. An oxidation ditch system was installed to control
odors. Cornell University personnel designed the system and provided
technical assistance and monitoring of the waste treatment system.
Calculation of NitrogemLosses
A loss of nitrogen has been consistently observed in the aerobic laboratory
units containing nitrified poultry wastewater and in the aerobic nitrifying
oxidation ditches. This loss was computed as the difference between the
amount of nitrogen that was fed to the system and the nitrogen that was
actually present in the mixed liquors plus any nitrogen that was removed
deliberately from the system such as for disposal or analysis. These
losses were attributed to denitrification and ammonia volatilization. The
gas traps in the laboratory systems permitted an estimate of the ammonia
volatilization losses. No effort was made to measure ammonia losses in the
oxidation ditch studies because of the inherent difficulties in such
measurements.
24
-------
If the possibility of nitrogen loss due to ammonia volatilization is ex-
cluded or known, the observed nitrogen losses can be attributed to denitri-
fication. Nitrogen mass balances in the aerobic systems should therefore
take into consideration the two sources of nitrogen losses. The relation-
ship between the nitrogen added, nitrogen content of the system and the
losses can be expressed by the following:
Total Nitrogen Added = Total Nitrogen in the system
+ nitrogen lost due to ammonia volatilization
+ nitrogen lost due to denitrification
+ nitrogen removed from the system for disposal or analysis
Nitrogen losses due to ammonia desorption from the flasks kept on the rotary
shaker were estimated by using the following relationship:
Quantity of nitrogen lost from the system = Kp-F-f [(volume of liquid)
(concentration of NH.-N)]
where KQ is the coefficient of ammonia desorption
inPH
F = —ly (K, and k are the dissociation constants
inpH + K b w
b/k of ammonia and water)
t = duration of ammonia desorption.
1C was experimentally determined by following the ammonia losses from solutions
of ammonium sulfate in water, rendered alkaline by addition of sodium hydroxide,
LandApplication of Hastes
A series of field studies were established to obtain information on the fate
of nitrogen in manure applied to soils to promote crop growth. These studies
included two sources of poultry manure, three rates of application and,
in two of the three experiments, two different times of application.
25
-------
An additional study was designed to study nitrogen balances in the soil and
corn plant in order that fertilization and manuring practices could be
regulated toresultin minimum water pollution with economic corn production.
Surface Runoff Losses, Field Studies
Two field studies permitted the collection of surface water runoff from
plots that had received application of poultry manure. The two manures
used were poultry manure stabilized by an oxidation ditch and fresh poultry
manure. Application rates of 0, 112, 224 kg N/ha were used. The first
study was established in 1972 on a Col lamer silt loam soil near the Ithaca
Poultry Farm, Cornell University. The second study was established at the
Agronomy Research Farm at Cornell University on a high lime Honeoye silt loam.
Weed control was accomplished through the application of chemical herbicides
to the soil surface prior to plowing. Manure was applied as a surface
application and plowed in within two days of application.
Individual plots measured 3.0 by 9.1 m and were surrounded by raised, cor-
rugated aluminum lawn edging so that only runoff from the plots were collected.
At the base of the plot slopes, collection troughs were installed and were
connected to a flow divider to divert one-twentieth of the entire amount
of flow into a storage tank. Runoff water was then measured and analyzed
for soluble orthophosphate (13), ammonium (15), nitrite nitrate (16), and
total soluble phosphorus (14). Sediment samples were collected and analyzed
for total phosphorus (17), total Kjeldahl nitrogen (11), and organic matter
(12). Soil samples were taken at regular intervals and at two depths, 0-20 cm
and 30-60 cm. Soil samples were analyzed for ammonium, nitrate nitrogen,
and total Kjeldahl nitrogen.
Analysis of the stabilized oxidation ditch mixed liquor that was applied is
presented in Table 2.
26
-------
Table 2. COMPONENTS OF OXIDATION DITCH MANURE USED AS A
SOURCE OF N FOR FIELD STUDIES, 1973
Parameter Concentration
(mg/£)
TKN
NH4N
NO,N
3
N02N
COD
Solids
3,360
1,274
0
0
28,806
28,485
Poultry Waste Residue Field Study
A field study was initiated in 1971 at the Aurora Research Farm on a
Honeoye silt loam soil. Plots measuring 3.0 by 18.2 m were established
using untreated poultry manure at the rates of 0, 56, 112, 224, 448, and
896 kg N/ha. A seventh treatment consisted of commercial fertilizer at
the rate of 22.4 kg N/ha. Corn was grown on all plots.
In 1972, the original plots of this study were split and the same treat-
ments repeated on one-half the original plots (Fig. 3). Corn was grown
again on these plots. In 1973, manure was applied only to the treatments
that had received 112 and 448 kg N/ha in 1972. Forty-five kg N/ha were
applied to the commercial fertilizer treatment (Fig, 3). In 1974, none
of the treatments received manure but 90 kg N/ha was applied to the treat-
ment receiving a commercial source of N. Corn was the crop grown each
year. Corn grain and stover yields were determined on each plot each year.
Corn grain and stover were analyzed for total N. Soil samples were
collected at regular intervals and analyzed for nitrate and ammonium.
27
-------
1971
1972
1973
1974
0
0
0
0
0
0
0
0
56
56
0
56
0
0
0
0
112
112
0
112
0
112
0
0
224
224
0
224
0
0
0
0
448
448
0
448
0
448
0
0
896
896
0
896
0
0
0
0
22
22
0
22
0
45
0
90
POULTRY MANURE
CHEM.
PERT.
Figure 3.
NITROGEN, kg/ha
Nitrogen applied over a 4-year period as poultry manure or chemical
fertilizer. Poultry waste residue study, 1971-1974.
28
-------
Forage Grass Response
A study to determine orchard grass and bromegrass response to applications
of poultry manure was conducted. Application rates of 0, 56, 112, and
224 kg N/ha were made using stabilized oxidation ditch mixed liquor and
fresh poultry manure as N sources. These rates were applied to established
grass stands in both fall and spring. Two cuttings of grass were harvested
from each plot.
GENERAL OBSERVATIONS ON THE RESULTS OBTAINED
Experiments were conducted in the laboratory to examine the effect of dif-
ferent factors influencing stabilization of wastes, nitrification and losses
of nitrogen. The following factors were examined: (a) rate of loading;
(b) pH value; (c) total solids; (d) total Kjeldahl nitrogen (TKN); and
(e) COD. The effect of several different loadings were examined by fol-
lowing the changes occurring in mixtures containing varying amounts of
poultry waste suspensions and nitrifying ODML. The samples of ODML used
in this study were from the oxidation ditches at (a) pilot plant, and
(b) Manorcrest Farm. The effect of the other factors were studied by
altering the pH value, COD, total solids, and TKN contents in the systems.
The ranges of these variables examined are indicated in Table 3. At the
same time, some large scale studies were conducted at the pilot plant on
the effect of different modes of operation of oxidation'ditches on nitrogen
contents of stabilized wastes.
The laboratory and pilot plant studies, and the observations on the per-
formance of the oxidation ditches at (a) the fur animal experiment station;
and (b) the two commercial poultry operations, indicated that significant
reductions in COD, total solids, and nitrogen contents occur during
aerobic stabilization. No objectionable odors were produced during the
aerobic stabilization of the manures.
29
-------
Table 3. COMPONENTS OF NITRIFYING WASTE SUSPENSIONS AND
THE INITIAL CONDITIONS IN THE LABORATORY-SCALE
NITRIFICATION SYSTEMS
(a) Components of
Control
System I
System II
System III
System IV
(b) Ranges of pH,
Trial 1 6.8
Trial 2 7.0
Trial 3 7.0
Trial 4 6.9
Trial 5 8.0
Trial 6 7.0
Trial 7 5.6
the mixtures used:
Water
(ml)
500
100
200
300
400
Nht-N, (N00 + NO;)
1111 H C. J
pH NH*-N
(mg/1 )
- 6.9 0 - 10
- 8.1 0 -120
- 7.7 6 -200
- 7.8 0 -120
- 8.6 60 -450
- 8.4 10 -350
- 7-0 120 -320
ODML
(ml)
1500
1500
1500
1500
1500
N, and TKN:
N02+N03-N
(mg/1 )
830
800
430
10 - 70
170 - 260
110 - 150
550 - 820
Poultry waste
suspension
(ml)
0
400
300
200
100
TKN
(mg/1)
440 - 1470
370 - 1150
1200 - 2300
900 - 2700
875 - 3500
650 - 3500
530 - 2800
30
-------
Nitrification occurred in all the stabilization systems examined. Nitro-
gen balances on the systems indicated that nitrogen losses occurred
during stabilization. These losses could be attributed to either desorp-
tion of ammonia or dissimilatory denitrification of the oxidized nitrogen.
Desorption of ammonia occurs at high pH values. Denitrification takes
place when the concentration of dissolved oxygen in the system reaches zero,
and when nitrites and nitrates function as electron acceptors during the
oxidation of carbonaceous substrate.
Corn, orchard grass and bromegrass responded to the application of raw
poultry wastes as well as the oxidation ditch mixed liquor. These responses
were directly proportional to the amount of nitrogen applied to the land
up to 224 kg per ha for corn and 170 kg per ha for the grasses. The res-
ponses did not appear to be significant beyond these levels of nitrogen
application. There were some seasonal differences in the responses of
corn and grasses. Some nitrogen from the manures applied to the bare
ground in the fall was leached from the soil or denitrified as shown by
soil analysis and crop response. Grasses on the same soil retained the
nutrients so that yields from the fall application were equal to those from
spring application. Application of manures increased the nitrate content
of the soils, but did not cause any runoff problems during the growing
season at the levels of application examined.
The details of the results of these experiments are described in sections
IV and V, and the significance of these results are discussed in section VI.
31
-------
SECTION IV
RESULTS OF THE ENGINEERING STUDIES ON NITROGEN CONTROL
LABORATORY STUDIES
In all the stabilization systems examined in the laboratory, the concen-
trations of dissolved oxygen were less than 1 mg per liter on the first
day of stabilization. Later, the dissolved oxygen concentrations increased
to more than 7 mg per liter. The oxygen uptake rates increased during the
first 24 hours and later decreased as the process of stabilization pro-
ceeded (Fig. 4). TKN and COD concentrations decreased as stabilization
proceeded.
In the systems which had an initial pH value of 7.0 and a high organic load,
the pH values increased as the organic nitrogen compounds were hydrolyzed,
and subsequently decreased later as nitrification occurred (Fig. 5). The
nitrogen balances showed that some losses of nitrogen could neither be
ascribed to ammonia desorption nor to decreases in the nitrate contents.
These unaccountable losses are presumably due to the denitrification of
NO^ occurring in the sludge floes in the system under seemingly aerobic
conditions.
Some of the salient observations on the changes that occurred in the different
laboratory trials are described under separate subheadings.
32
-------
TRIAL I
I 1
I I
10
Figure 4.
456789
DECEMBER 1973
Changes in the oxygen uptake rate during waste stabilization.
33
-------
0
Figure 5a. Changes in pH during stabilization and nitrification.
2000r-
Figure 5b. Changes in concentration of nitrates during stabilization and
nitrification.
34
-------
Trial #1
In this trial, the systems were started at a low pH value. As the stabili-
zation proceeded, the pH values of systems 1, 2, and 3 increased to 8.5
before they decreased to 5.3. The concentration of oxidized nitrogen
steadily increased as the stabilization proceeded.
In the control system and in system 4, the changes in pH were not signifi-
cant so as to cause losses of nitrogen due to desorption of ammonia. In
systems 1, 2, 3, and 4, decreases in nitrate contents were noted. The
nitrogen losses from the systems and the estimates of losses due to
(a) ammonia desorption; (b) denitrification; are shown in Table 4.
The unaccountable losses shown in Table 4 are presumably due to denitri-
fication.
Trial #2
The changes in the total nitrogen content of the different systems are
shown in Figure 6. The nitrogen losses and the estimates of losses due
to ammonia desorption and denitrification are summarized in Table 5.
The losses of nitrogen due to denitrification occurring in the sludge
floes have been shown in the table as unaccountable nitrogen losses.
The cumulative oxygen uptake data presented in Figure 7 indicate that
higher oxygen demand is exerted by units having higher nitrogen concen-
trations.
Trial #3
In the control system of this trial, the mixed liquor did not contain any
significant amount of NH*- N. The content of oxidized nitrogen steadily
increased. In system 1, there was no apparent decrease in the nitrate
content. In systems 2, 3, and 4, decreases in nitrate contents were noted
35
-------
co
Table 4. NITROGEN LOSSES DUE TO AMMONIA DESORPTION AND DENITRIFICATION IN THE
STABILIZATION SYSTEMS OF TRIAL #1
TKN (mg/1)
System
Control
1
2
3
4
PH
Range
5.9-6.8
5.2-8.5
5.3-8.3
5.3-8.1
5.4-7.6
Initial
438
1470
1176
928
770
Final
343
798
711
396
410
(N09+NOJ-N
Cm O
Initial
829
829
792
650
759
(mg/1)
Final
874
776
454
1184
1280
Nitrogen Loss (mg/1 )
Ammonia
Desorp-
tion(est. )
0
318
233
114
0
Observed U.A.*
Denitrifi-
cation
0 50
67 340
682
262
458
Total
50
725
915
333
385
*U. A.-unaccountable
-------
co
2000 r—
TRIAL n (DEC. 12,73 TO JAN. 10, 74)
500
0
10
15
DAYS
20
25
30
Figure 6. Total nitrogen contents of the wastes in the different systems
during stabilization.
-------
co
oo
Table 5. NITROGEN LOSSES DJE TO AMMONIA DESORPTION AND DENITRIFICATION IN THE
STABILIZATION SYSTEMS OF TRIAL #2
System
Control
1
2
3
4
pH
Range
6.7-7.0
6.4-8.0
6.2-8.2
6.3-8.2
6.5-8.0
TKN
Initial
371
742
917
1085
1144
(mg/l)
Final
322
322
357
361
462
2 3
Initial
804
804
804
804
804
>N (mg/l)
Final
756
1027
980
890
874
Ammonia
Desorp-
tion(est.
0
170
117
114
130
Nitrogen Loss
Observed
Denitrifi-
) cation
48
0
158
336
482
(mg/l )
U.A.*
49
27
109
188
-
Total
97
197
384
638
612
*U.A.-unaccountable
-------
3000 i—
CO
N
O>
E
2000 —
z
UJ
o
X
o
UJ
<
_i
ID
o
1000 —
0 23
1 1
4567
DAYS
1 1 1
8 9
1 !
13
14
15
17
18
19
20
Figure 7. Cumulative oxygen uptake over time.
-------
during the course of stabilization. The initial and final concentrations
of nitrogen, and the losses of nitrogen due to the three different mecha-
nisms given in Table 6.
Trial #4
The control system and system 4 contained only traces of NH4-N. Decreases
in nitrate contents were noted in all the systems. The initial and final
concentrations of nitrogen in the systems, and the losses of nitrogen
due to the three different mechanisms are given in Table 7. Nearly
half the amount of the total nitrogen of system 4 was lost during stabili-
zation due to denitrification under seemingly aerobic conditions.
Trial #5
Losses of nitrogen due to ammonia desorption occurred in systems 1, 2, 3,
and 4. The pH values of the liquor in the control system during the
period of this study were in the range of 5.9 to 6.1. Thus, there were no
losses due to ammonia desorption. During the course of stabilization,
decreases in nitrate contents in systems 1, 2, 3, and 4 were noted. The
results of this study are summarized in Table 8.
Trial #6
The changes in nitrogen contents of the systems, and the extent of nitrogen
losses due to the different mechanisms are given in Table 9. NI-L-N was
found only in trace amounts in the control system. Nitrogen losses due to
ammonia desorption occurred in the systems 1, 2, 3, and 4. The amounts of
nitrogen losses due to ammonia desorption were directly related to the
initial TKN contents of the system (Table 9). Some decreases in the
nitrate contents were noted during the course of stabilization in systems
1, 2, 3, and 4.
40
-------
Table 6. NITROGEN LOSSES DUE TO AMMONIA DESORPTION AND DENITRIFICATION IN THE
STABILIZATION SYSTEMS OF TRIAL #3
TKN (mg/1)
System
Control
1
2
3
4
pH
Range
7.7-8.2
7.5-8.3
7.3-8.7
7.2-8.8
7.1-8.9
Initial
1215
1274
1701
1939
2296
Final
707
672
774
1092
1256
(N02+N03)
Initial
431
229
210
160
123
-N (mg/1
Final
596
487
442
431
342
) Nitrogen Losses (mg/1)
Ammonia
Desorp-
tion(est. )
0
94
150
287
525
Observed
Denitrifi-
cation
0
0
210
224
143
U.A.*
343
250
335
65
153
Total
343
344
695
576
821
*U.A.-unaccountable
-------
Table 7. NITROGEN LOSSES DUE TO AMMONIA DESORPTION AND DENITRIFICATION IN THE
STABILIZATION SYSTEMS OF TRIAL #4
TKN (mg/1)
System
Control
1
2
3
4
PH
Range
7.0-7.8
7.8-8.0
7.3
7.2
6.9
Initial
903
1124
1593
2107
2720
Final
455
448
644
864
889
(N02+N03)-N (mg/1)
Initial
73
39
22
17
14
Final
294
353
487
406
378
Ammonia
Desorp-
tion(est. )
0
321
378
617
0
Nitrogen Loss (mg/1)
Observed U.A.*
Denitrif i-
cation
56 171
50
17 89
17 220
53 1414
Total
227
362
484
854
1467
*U.A.-unaccountable
-------
CO
Table 8. NITROGEN LOSSES DUE TO AMMONIA DESORPTION AND DENITRIFICATION IN THE
STABILIZATION SYSTEMS OF TRIAL #5
TKN (mg/1)
System
Control
1
2
3
4
pH
Range
5.9-6.1
7.0-8.8
8.4-8.6
6.8-8.6
6.2-8.6
Initial
875
3465
3136
2699
1813
Final
525
2352
1971
1050
865
(NQ,+N03)-N(mg/l)
Initial
260
179
224
252
190
Final
465
36
42
370
644
Ammonia
Desorp-
tion (est.)
0
997
840
785
371
Nitrogen Loss (mg/1)
Observed U.A.*
Dem'trifi-
cation
0
179 80
507
340 406
498
Total
-3
1256
1347
1531
494
*U.A.-unaccountable
-------
tr-
9. NITROGEN LOSSES DUE TO AMMONIA DESORPTION AND DENITRIFICATION IN THE
STABILIZATION SYSTEMS OF TRIAL #6
TKN (mg/1)
Sy s tern
Control
1
2
3
4
pH
Range
7.2
7.0-8.9
7.1-8.9
7.3-8.8
7.4-8.4
Initial
648
3535
2695
2307
1820
Final
403
1638
1355
973
770
(N00+NO,)-N (mg/1)
C- O
Initial
153
115
115
120
112
Final
322
364
342
557
742
Nitrogen Loss
Ammonia
Desorp-
tion(est. )
0
1554
895
579
238
Observed
Denitrifi-
cation
0
126
173
109
96
(mg/1 )
U.A.*
76
-
45
209
86
Total
76
1648
1113
897
420
*U.A.-unaccountable
-------
Trial #7
Nitrogen losses due to ammonia desorption were neglible in all the systems
examined in this trial. The cumulative oxygen uptake of the systems as a
function of the period of stabilization is shown in Fig. 8. The TKN contents
of the systems during the period of this study are shown in Fig. 9. The
cumulative oxygen uptake and the removals of COD and nitrogen obtained in
the systems are given in Table lOa. These results indicate that the removal
of COD and nitrogen is directly related to oxygen uptake by the systems.
Results given in Table lOb suggest that nitrogen losses due to denitrifi-
cation appear to be: (a) directly proportional to oxygen uptake rates in
the systems; and (b) inversely proportional to the equilibrium dissolved
oxygen concentrations in the systems.
PILOT PLANT STUDIES
As the oxidation ditch began operation, losses of nitrogen due to ammonia
volatilization were observed. These losses became minimal once nitrification
was established and the pH dropped below 7.0. Except for some initial
ammonia odor, the oxidation ditch had no odor during the various modes of
operation, thus confirming that these systems can be used as effective devices
for odor control. Some foaming occurred during transition from one mode of
operation to another. This was not a severe problem since the foam subsided
quickly as equilibrium occurred.
Material balances were computed for nitrogen and COD for each mode of oper-
ation to ascertain the performance of the ditch.
45
-------
20
0
cc
o
u_
to
O
o>
E
15
LU
>
O
10
0
• C
A I
on
on
•E.
REFER TO
RIGHT SCALE
10
15
DAYS
20
25
35
30
M
*
cr
e
25%
x
E
20 ul
CL
10
o
30
Figure 8. Cumulative oxygen uptake in the different systems during stabilization.
46
-------
2500H-
2000k-
I500H-
1000
500
Figure 9. TKN contents of the wastes in the different systems during stabilization,
-------
00
Table TOa. CUMULATIVE OXYGEN UPTAKE (COU), NITROGEN AND COD REMOVALS
OBSERVED DURING STABILIZATION OF WASTES IN THE DIFFERENT
SYSTEMS OF TRIAL #7
Days
1
2
7
9
13
16
20
23
27
Control
Removal of
COU COD N
(mg) (mg) (mg}
212 0 0
408 - 1 33
1140 - 117
1350 1134 87
1746 - 164
2010 - 148
2264 1374 92
2425 1178 156
2608 1604 154
System 1
COU
(mg)
6480
10295
21185
23863
27113
29091
31927
32986
34180
Removal of
COD
(mg)
0
-
5754
10815
-
12439
18921
-
23566
N
(mg)
0
458
1081
1165
1638
1527
1607
1443
1553
System 2
COU
(mg)
1944
3544
9399
11197
14440
16121
17737
18436
19276
Removal of
COD
(mg)
0
-
6976
18494
-
20030
23131
-
25596
N
(mg)
0
409
662
818
1050
767
953
761
818
System 3
COU
(ma)
1184
2310
7428
8650
10265
11079
11866
12352
12996
Removal of
COD
(mg)
0
-
1568
3662
-
4447
4347
7566
9677
N
(mg)
0
91
342
-
443
337
437
284
413
System 4
Removal 01
COU COD N
(mg) (mg) (mg
849 - 0
1811 - 132
5402 8898 129
6088 7328 12
7358 - 85
8144 8413 60
8954 8362 169
9396 10238 282
9972 11517 180
-------
Table lOb. EFFECT OF EQUILIBRIUM DISSOLVED OXYGEN CONCENTRATION
AND OXYGEN UPTAKE RATE ON NITROGEN LOSS
Days
Control
N
Rr D.O. Loss
(mg/hr)(mg/l)(mg)
System 1
N
Rr D.O. Loss
(mg/hr)(mg/l )(mg)
System 2
N
Rr D.O. Loss
(mg/hr)(mg/l)(mg)
System 3
N
Rr D.O. Loss
(mg/hr)(mg/l)(mg)
System 4
N
Rr D.O. Loss
(mg/hr)(mg/l)(mg)
co
7-9 4.8 9.0 102
16-20 3.1 9.3 120
63.9 3.6 1123
30.1 7.1 1570
43.2 4.9 740
15.4 7.9 910
35.6 5.4 342
9.1 8.8 387
19.1 7..6 71
8.5 8.5 114
-------
Operational Mode I
In this mode of operation, the oxidation ditch was operated as an aerated
holding tank with continuous input of manure from the birds. The opera-
tional parameters of the ditch are given in Table 11.
Table 11. OPERATIONAL PARAMETERS OF OXIDATION DITCH -
MODE OF OPERATION I
Number of birds 227
Number of days operated 276
Immersion depth of rotor 6" (15.2 cm)
Liquid volume 2000 gallons (=7600 liters)
Liquid depth 20" (51 cm)
No odorous conditions were noted and nitrites rather than nitrates predomi-
nated during the entire period of operation. The solids accumulated to a
concentration of 8.2% at which point the rotor was unable to pump the mixed
liquor. Nitrification was sustained even at this concentration of solids.
The nitrogen balance is presented in Table 12.
The results of this mode of operation indicated that in spite of the high
dissolved oxygen concentration in the mixed liquor (>5 mg/1) and active
nitrification, about 30% of the input nitrogen was lost. This loss was
attributed to localized denitrification in anaerobic pockets of the mixed
liquor.
50
-------
Table 12. NITROGEN BALANCE - MODE OF OPERATION I
Nitrogen, kg
Input 51.7
Accounted 31.8
Unaccounted or losses 19.9
% loss 31.1
Operational Mode II
The ditch operated as a continuous flow device with intermittent denitri-
fication. Solids equilibrium was maintained by deliberately wasting some
effluent. The operational details of the oxidation ditch in this mode of
operation are given in Table 13.
As part of this mode of operation, two in situ denitrification studies were
made in the ditch (Table 13). During these studies the rotor was stopped
to achieve the losses of oxidized nitrogen. In the first denitrification
phase, continuous flow operation was temporarily suspended and no overflow
was permitted. The birds continued to add wastes to the ditch, thus adding
an additional oxygen demand for denitrification. While the birds added
wastes during the second denitrification phase, some overflow was permitted.
In both studies the rotor was turned on for a portion of each day to mix
the ditch contents.
51
-------
Table 13. CONTINUOUS FLOW OPERATION OF THE OXIDATION
DITCH WITH SOLIDS CONTROL AND WITH INTER-
MITTENT "IN SITU" DENITRIFICATION OF THE
MIXED LIQUOR
a) Period of operation - October 19, 1972 - April 10, 1973
(173 days)
Phases during operation Days
1. Filling 13
2. Flow-through 69
3- In situ denitrification 16
4. Filling 4
5. Flow-through 64
6. In situ denitrification 7
b) Immersion Depth = 2" (5.1 cm)
c) Volume of oxidation ditch = 1600 gallons (6056 liters)
d) Number of birds = 250
e) Total solids concentration in the mixed liquor = 0.5%
From detailed analyses of the data, nitrogen balances were computed and
the losses of nitrogen in each phase of operation of the oxidation ditch
were established (Table 14). The loss of nitrogen (about 73%) observed
during the initial filling period is high and may be due to: (a) ammonia
volatilization which was greater when the system was restarted, (b) some
52
-------
Table 14. NITROGEN LOSSES DURING DIFFERENT MODES OF OPERATION WITH
SOLIDS CONTROL AND WITH INTERMITTENT "IN SITU" DENITRIFICATION
Nitrogen Loss %a
Initial filling (no flow through) 73
First flow-through period 31
"In Situ" denitrification 66
Second filling period 32
Second flow-through period 29
"In Situ" denitrification 52
aLoss of N? added to the system during the mode of operation
incidental denitrification of N0~ and N0~ contained in the initial material,
and (c) errors in obtaining a representative sample of the mixed liquor.
Compaction of the solids in the mixed liquor took place whenever the
rotor was stopped, and it was difficult to obtain a uniform sample.
In the first flow-through period the loss in nitrogen was about 31%.
This was primarily due to uncontrolled denitrification even though "aerobic"
conditions prevailed in the system. Ammonia volatilization was negligible.
The pH of the ODML was well below 7.0 and there was active nitrification.
Therefore, the losses of nitrogen observed in the system could be attributed
to denitrification even though there was active nitrification in the system.
In the first controlled denitrification phase (16 days) the nitrogen loss
was about 66% of the input nitrogen during that period. During this
53
-------
denitrification period, mixing was provided by operating the rotor for
about one half hour every day. It is doubtful whether any significant
part of the nitrogen input into the ditch during this period was nitri-
fied. The losses of nitrogen input as indicated in this period only
represent the loss of the nitrites and nitrates which were in the mixed
liquor at the start of the denitrification period.
The nitrogen losses in the second filling period were not as high as
during the first period since the ditch contents were well equilibrated
and nitrification was induced rapidly due to the presence of adequate
numbers of nitrifying organisms in the seed material. The nitrogen loss
during this period was 32%.
The second flow-through period also showed a nitrogen loss (about 29%)
which was comparable to the first flow-through period (about 31%).
These losses were primarily due to uncontrolled denitrification as the
pH value of the ODML was low and unfavorable for ammonia volatilization.
The nitrogen losses during the second controlled denitrification period
was 52%, less than that encountered during the first denitrification
period. This may be due to the lower amount of oxidized nitrogen present
in the ditc1: Juring this period as compared to that of the first controlled
denitrification period. Some oxidized nitrogen was lost via the effluent
as the ditch was operated on a continuous flow basis during this period.
The rotor was turned on for about eight hours per day during this period
to provide mixing. With such an operation, the denitrification rates were
higher as compared to the rates obtained during the previous controlled
denitrification period when mixing of the contents of the ditch was
provided by operating the rotor for one half hour daily.
54
-------
Because of the difference in time periods for the denitrification periods
and the regular flow-through periods of the ditch and the amount of oxi-
dized nitrogen present, losses due to denitrification during continuous
operation of the ditch were much higher than the losses achieved during
deliberate denitrification. The total overall loss of nitrogen due to the
deliberate denitrification in the two controlled denitrification in the
two controlled denitrification stages was about 8% as compared to 23%
loss attributable to uncontrolled denitrification under "aerobic"condi-
tions, i.e., continuous operation of the rotor in the ditch. The amount
of nitrogen lost during the two filling periods was 7.3% of the total
nitrogen input to the oxidation ditch during the overall period. Some
of this loss was due to ammonia volatilization occurring in the system
when the pH value of the ODML was high. Higher pH values and NH. concen-
trations were observed during the filling periods than those observed
during the actively nitrifying flow-through periods.
The rates of denitrification were 0.08 and 0.24 mg of oxidized nitrogen
per hour per gram of total solids, respectively, during the first and
second denitrification periods. Adequate mixing appears essential to
achieve higher denitrification rates. The mixing did not inhibit denitri-
fication.
A summary of the nitrogen losses over the period of the oxidation operation,
(173 days), is indicated in Table 15.
During the first "flow-through" stage of the oxidation ditch, nitrification
occurred. At the same time significant amounts of nitrogen were lost.
This was presumably due to localized denitrification in the anoxic zones
of the floe since ammonia volatilization was negligible. The probability
for nitrogen loss through this mechanism may be high in a nitrifying
system if the localized anoxic conditions for denitrification are increased
55
-------
Table 15. NITROGEN LOSS IN OXIDATION DITCH SYSTEM9-
OPERATIONAL MODE II
Percent
Total N loss during flow-through stages 23.2
Total N loss during denitrification 8.0
Total N in effluent 62.1
Total N loss during the two filling periods 7.3
Expressed in terms of the overall estimated nitrogen input to the system.
while maintaining active nitrification. This may be achieved by increasing
the solids concentration. Addition of raw manure will increase both the
suspended solids content and the oxygen demand of the system and increase
the probability of anoxic conditions in the microbial floe as a result of
increased concentration of particulate matter and decreased oxygen transfer.
Under these circumstances, the probability for denitrification of NOl and
NOl will increase.
Operational Mode III
During this phase of operation attempts were made to control the solids
content of the ODML without adding fresh water. The mixed liquor from
the oxidation ditch was pumped intermittently into a settling tank.
The mixed liquor was settled and the supernatant liquid was returned to
the ditch. Some make-up water, approximately 25 gallons per week during
summer months occasionally was added to compensate for the losses due to
evaporation. No water was added during the winter.
56
-------
After the initial period during which the detention time in the settling
tank was variable, a detention time of 8.5 days was maintained. Two
hundred gallons of sludge that accumulated in the settling tank were
periodically wasted every 3 to 4 weeks by opening a valve located at the
bottom of the settling tank.
In addition to monitoring the total solids content, chemical analyses
of the mixed liquor from the ditch, and the supernatant and the wasted
sludge from the settling tank were made on a regular basis. From this
data, nitrogen balances were computed.
The operational parameters for this mode of operation are presented in
Table 16 with the results of the nitrogen balance in Table 17.
Table 16. OPERATIONAL PARAMETERS OF OXIDATION DITCH -
OPERATIONAL MODE III
Number of birds = 226
Number of days = 99
Immersion depth of rotor, liters = 5.2 (2")
Liquid volume, liters = 6056 (1600 gallons)
Volume of settling tank, liters = 1685 (455 gallons)
Detention time in settling tank = 8.5 days
Total solids in ODML = -1-3%
57
-------
Table 17. TOTAL NITROGEN BALANCE IN OPERATIONAL MODE III
a) Total nitrogen (TN) losses from the oxidation ditch - settling tank
system:
TN input to system = 42.04 kg
ATN in oxidation ditch = 0.65 kg
TN in wasted sludge = 7.37 kg
ATN in supernatant = 0.11 kg
TN losses = TN input - ATN in ditch - TN in sludge - ATN in supernatant
= 42.04 - 0.65 - 7.37 - 0.11 = 33.91 kg
% TN losses = -~|1 x 100 = 80.6
b) Total nitrogen loss accomplished in settling tank:
TN losses in settling tank = TN input to settling tank - TN in wasted
sludge - ATN in supernatant
= 11.62 - 7.37 - 0.11 = 4.14 kg
% TN loss due to denitrification = 4.14 x 100
in settling tank 42.04 ~
c) TN loss in oxidation ditch = 80.6 - 9.8 = 70.8%
58
-------
The results of this mode of operation indicated that significant losses
of nitrogen from the system can be achieved by recycling the mixed liquor
through a settling tank. About 10% of the total nitrogen input from the
birds was removed in the settling tank while a major portion, about 70%,
was removed in the oxidation ditch. These losses in the ditch were signi-
ficantly higher than the 30% of losses generally observed in the ditch
when it was operated without the recycling of mixed liquor. These
increased losses in nitrogen in this mode of operation may be due to
(a) seeding of the ditch by a highly efficient denitrifying population
which is carried over by recycling the supernatant, and (b) the very
long hydraulic detention time provided for the nitrate containing super-
natant fraction of the mixed liquor due to recycling to the ditch.
The above summary identifies the TN losses from the entire system. The
loss of nitrogen due to the settling tank also was computed. The total
nitrogen and NO" plus NO--N profiles for the ODML entering and the super-
C. O
natant leaving the settling tank are presented in Fig. 10 and 11. These
patterns and the data collected on the wasted sludge indicate that a
significant portion of TN entering the settling tank from the oxidation
ditch was removed due to settling and denitrification. The losses of the
total nitrogen entering the settling tank due to denitrification amounted
to about 36%, while 63% of the TN loss was removed in the sludge. However,
the total nitrogen removal in the settling tank represnted only 10% of the
total input nitrogen from the birds.
Operational Mode IV
In the previous modes of operation, aeration was provided by operating the
rotor continuously. In this mode the effect of curtailing the rotor aeration
on nitrogen losses was studied. Such an operation should provide an oppor-
tunity for the mixed liquor to denitrify in the ditch without the aid of a
59
-------
IOOCH
800H
UJ
CD
g 600H
fc 400 H
200H
INFLUENT
RECYCLED EFFLUENT
20
40
60
80
100
DAYS
Figure 10. Total nitrogen profile of the influent and effluent of settling tank
June 6 - September 13, 1973.
60
-------
250
200 H
z" 1501
i
I 10
O
z
4
INFLUENT
• RECYCLED EFFLUENT
5CH
20
40
DAYS
60
80
100
Figure 11.
Oxidized nitrogen profiles of influent and effluent of settling tank
June 6 - September 13, 1973.
61
-------
settling-denitrfficatlon tank. Some savings in power consumption may
be realized by turning off the rotor.
During this mode the rotor was connected via a time switch to the power
line. The switch was adjusted to a predetermined time interval and con-
trolled the period of aeration by the rotor. Two experimental runs
were made in which the rotor was operated for 16 and 12 hours per day
respectively. Each experimental run lasted for about three weeks.
Wastes from the birds were added continuously. The ditch was operated
as an aerated holding tank with no overflow. Analyses for total solids,
TKN, NCL-N, NCU-N, NH.-N and COD were performed routinely. The nitrogen
balances are presented in Tables 18 and 19.
The results of this study indicated that it was possible to remove up to
90% of the total nitrogen input to the oxidation ditch by manipulating
the aeration period. When the rotor was operated for 12 hr/day, larger
nitrogen losses were observed than when the rotor was operated for 16
hr/day. From the profiles of oxidized nitrogen concentration of the mixed
liquor at the above periods of rotor operation (Fig. 12), the NO--N con-
centration progressively decreased in the mixed liquor when the aeration
period was 12 hr/day, whereas it was relatively constant when the period
of aeration was 16 hr/day. In both instances the pH of the mixed liquor
was near neutral suggesting that the nitrogen losses were not due to
ammonia volatilization and primarily were due to a nitrification-denitri-
fication mechanism.
The observed total nitrogen loss coupled with the progressive decrease and
the eventual disappearance of mixed liquor NO--N concentration in the 12
hour mode of rotor operation suggested that the extent of denitrification
exceeded that of nitrification. However, in the 16 hour mode of rotor
operation, the mixed liquor NCL-N concentration remained relatively
62
-------
Table 18. NITROGEN BALANCE IN AN OXIDATION DITCH
OPERATIONAL MODE IV (ROTOR ON FOR
16 HOUR/DAY9)
Days
0
2
6
9
13
16
20
23
Cumulative
TN input
(kg)
-
1.1
3.3
4.9
7.2
8.8
11.0
12.7
% TN
loss
_
34.5
49.3
51.1
53.6
58.2
62.5
69.6
aAmount of oxidized nitrogen left in ODML = 2.7 kg
63
-------
Table 19. NITROGEN BALANCE IN AN OXIDATION DITCH -
OPERATIONAL MODE IV (ROTOR ON FOR
12 HOUR/DAY3)
Days
0
4
7
11
14
18
21
Cumulative
TN input
(kg)
_
2.1
3.7
5.9
7.5
9.6
11.2
% TN
loss
-
44.4
82.6
91.3
95.2
92.5
88.3
aAmount of oxidized nitrogen left in ODML = 0 kg
64
-------
500-
400-
o> 300-
E
i
ro
O
200-
100-
ROTOR ON
16 hr/day
ROTOR ON
12 hr/day
10 15
DAYS
20
25
Figure 12. Profile of NCL-N in ODML - operational mode IV.
-------
constant at 450 mg/1 suggesting that the extent of nitrification was
not less than that of denitrification. If the remaining N03-N were
denitrified subsequently, the total nitrogen losses would amount to
about 90% and would be comparable to the nitrogen losses observed when
the ditch was aerated 12 hrs/day.
There appears to be an optimum period of aeration between 12 and 16
nrs/day for this system at which the extent of nitrification equals
that of denitrification. If the mixed liquor is aerated for such a period
in a day, then it would be possible to achieve no accumulation of oxidized
nitrogen, while maintaining odorless conditions and accomplishing high
nitrogen removals without the aid of additional units for separate deni-
trification.
FULL SCALE OXIDATION DITCH SYSTEMS
Houghton Operation
In early 1972, a full scale oxidation ditch stabilization system was
installed in a nearby poultry farm. The system was put in by the owner,
Mr. C. L. Houghton, after he had seen the pilot plant oxidation ditch at
Cornell University. Prior to the installation of the oxidation ditches,
the waste handling on the farm consisted of liquid collection and anaero-
bic storage in pits located under the cages. The oxidation ditches in
this operation were formed by connecting both ends of a pair of manure col-
lection pits. Following the installation of the system, personnel of the
Department of Agricultural Engineering at Cornell have worked closely with
Mr. Houghton to monitor the system and cause it to operate satisfactorily.
The results of observation made during 1972 have been described in the
earlier report to the EPA (5).
66
-------
The objective of the stabilization system in this operation is odor control.
Attempts have been made to assess the performance of the system as a
nitrogen control device under these conditions of operation. The oxidation
ditch system is operated as an aerated holding tank. The cages are above
the ditches and input of manure to the stabilization system is continuous.
The large amount of water leakage from the dew drop watering system
necessitates the periodical removal of the mixed liquor from the ditches.
Foaming is controlled by addition of motor oil to the mixed liquor.
Variations in factors such as quantity and frequency of removal of the
mixed liquor from the ditches resulted in solids retention times ranging
from 12 to 36 days and permitted the evaluation of the effects of varying
detention times and other operational conditions on the performance of
the system.
Throughout this study period, estimates of daily loading of total nitrogen,
solids, and COD were made by analyzing 24 hour composite samples of bird
excreta. Samples of mixed liquor were routinely collected and analyzed
for the total solids content, COD and the different forms of nitrogen.
Mass balances were made to determine (a) the efficiency of nitrogen and
COD removals, and (b) the extent of conversion of organic nitrogen to
other forms.
Throughout this study, the stabilization systems have achieved their objective
of odor control. The total nitrogen input to the system varied from
1012 to 1430 kg per month. The extent of the removal of nitrogen and COD varied
from 29 to 53, and 26 to 59 percent respectively. The total nitrogen
input to the system and the quantities of nitrogen accounted for during the
eleven month period are shown in Figure 13.
67
-------
61—
14 ~
12
10
0
TOTAL NITROGEN
INPUT
x' TOTAL NITROGEN
S ACCOUNTED FOR IN DITCH
I 23456789 10 II
MONTHS
Figure 13. Nitrogen input and the quantity accounted for in the ditch,
68
-------
The pH value of the mixed liquor was always alkaline. Except for a short
period in October 1972, when the pH was in the range of 7.6 to 7.9 and
nitrites were present in the mixed liquor, the pH value of the liquor
was in the range of 8.1 to 8.4. Oxygen input to the system was insuffi-
cient to maintain a residual dissolved oxygen throughout the length of
the channel. Therefore, the nitrogen removals from the system were
largely due to ammonia volatilization. The concentration of ammoniacal
nitrogen fell sharply in the month of October. The losses in nitrogen
during this period, when nitrification was also noted, were due to ammonia
volatilization and denitrification of the oxidized nitrogen compounds.
The analytical data were further evaluated to develop predictive relation-
ships between manurial nitrogen inputs to the ditches, nitrogen contents
of ODML, and losses of nitrogen due to ammonia desorption. The total
numbers of birds in the operation, the loadings, the average concentrations
of NH.-N during the different months of operation, and other details
relating to this study are given in Table 20. The total number of birds
was fairly constant. Fluctuations in the NH.-N concentration during each
of the months of April, May, June, July, August and September, were minimal.
However, the total volume of ODML of the systems changed due to changes
made in the operation of the oxidation ditches.
If A is the rate of addition of manurial nitrogen to the oxidation ditch,
and 50% of the nitrogen in the poultry excreta is easily convertible to
NH*, then the rate of NH* input to the system is A/2.
If V is volume of ODML in the system, the rate of increase in the concentra-
tion of NH*-N is A/2V.
Let AC = change in NHt-N concentration during At (11)
= , • At - K • F • C • At
69
-------
Table 20. INPUTS TO THE OXIDATION DITCHES, MEAN CONCENTRATIONS OF AMMONIACAL
NITROGEN, pH, AND TEMPERATURE OF ODML AT THE HOUGHTON FARMS
Inputs to the ditches
Month
February
March
April
May
June
July
August
September
October
November
December
Number
of birds
14,259
14,114
14,062
12,395
14,777
14,655
14,533
14,450
13,850
14,855
14,740
Total
Solids
(kg)
15,366
16,259
12,019
14,279
16,473
16,882
16,741
16,109
15,955
16,560
16,980
COD
(kg)
11,950
12,775
9,347
11,105
12,812
13,129
13,020
12,528
12,082
12,879
13,206
TKN
(kq)
1,294
1,370
1,012
1,203
1,388
1,422
1,410
1,357
1,344
1,395
1,430
Liquid
Volume Depth
(liters) (inches)
110,576
109,367
198,308
194,810
204,730
213,604
212,395
211,628
213,040
212,878
199,570
18
18
32
32
33
35
35
35
36
36
33
ODML
Cone, of
NH4'N PH
(mg/1 )
2,457
2,436
1,560
1,782
1,596
1,266
1,137
1,054
472
812
1,181
8.5
8.4
8.2
8.3
8.2
8.2
8.2
8.1
7.6
7.9
8.1
Temp.
°C
15
16
20
24
27
28
25
23
17
18
19
-------
where KQ is the ammonia desorption coefficient for the oxidation
ditch system;
F is the fraction of ammoniacal nitrogen in ODML available
for desorption. F is dependent upon pH and temperature.
pH oH
F = 10 /[KI/I^ + 10P ] where Kfa and 1^ are the dissoci-
ation constants of ammonia and water, respectively; and
their values are dependent upon temperature.
C is the concentration of ammoniacal nitrogen in the ODML.
When the system has reached a steady state,
W = KD ' F ' C
A
Therefore, Kn = 9WFr (13)
\j <_ v r w
The desorption of ammonia in the oxidation ditch system occurs from the en-
tire surface area of the liquid exposed. However, strong smell of ammonia
gas was always found near the rotors. In comparison to the ammonia losses
occurring in the channels, the losses near the rotor are large. The ammonia
desorption occurring in the oxidation ditch could be considered as almost
entirely due to the action of rotors. The extent of liquid-air contact area
created by a rotor is largely dependent on the design and on the rotor immer-
sion depth and speed (RPM). When rotors of same design are operated under
similar conditions of immersion depth and speed, the extent of surface renewal
occurring in the system are proportional to the length of the rotor. There-
fore, an ammonia desorption rate that is characteristic of the rotor could
be calculated in a manner similar to the oxygen input capacity of the rotor.
The available data related to the operation of the rotors at only one immer-
sion depth and based on this information, the KD value of the rotors was found
to be 0.00584 per hr per ft of the rotor. More evidence is necessary to
find the value of KD at other rotor immersion depths.
71
-------
With the value of KD for the rotor known, estimates of losses due to
ammonia volatilization can be calculated. If nitrogen losses in the
system are only due to ammonia volatilization, and the system has
reached a steady state condition, it is possible to calculate the
inputs of nitrogen to the system. The quantity of nitrogen actually
entering the system, and the estimates of nitrogen inputs based on the
use of Equation 11, are shown in Figure 14. These results indicated
that the estimates of nitrogen input show some agreement with the
actual nitrogen inputs except in those months where some degree of
nitrification occurred (September, October, and November).
Manorerest Farms
The two oxidation ditches in this operation are installed beneath the
caged laying hens, and each receives the wastes from 4,000 birds. The
mode of operation of these ditches can be described as continuous flow
operation with supernatant recycle from the settling tanks. The stabili-
zation systems have effectively functioned as an odor control device
since their installation in August 1973. The aeration devices installed
for the ditches are different in their design and oxygenation capacities.
The rotor providing oxygen to ditch no. 1 is of the conventional cage-type
rotor design. The rotor providing oxygen to ditch no. 2 is a brush aerator.
The oxygen input by the conventional rotor is much higher than the brush
aerator.
Twenty-four hour composite samples of bird excreta, samples of mixed liquor,
and supernatant liquors returning to the ditches were analyzed for forms
of nitrogen and COD. Mass balances were computed to assess the performance
of the ditches as nitrogen control systems.
A high degree of nitrification was noted (Fig. 15) and there were no ammonia
odors in the poultry houses after nitrification had set in the system.
72
-------
o
2
O
cr
o
u
CO
CO
2500
2000
500
1000
500
0
CONCENTRATION
OF
PREDICTED BY
EQUATION FOR
AMMONIA DES
JFMAMJ JASOND
MONTH
Figure 14. Actual quantity vs. nitrogen estimates.
73
-------
1600 —
0
0
10
20
50
60
30 40
DAYS
Figure 15. Effect of operation of oxidation ditch on nitrification.
74
-------
Figures 16 and 17 show the fluctuations in the concentrations of the dif-
ferent forms of nitrogen after the systems had reached steady state.
Even though about 70% of the organic nitrogen in the manure was converted
to ammonium, only small amounts of nitrites and nitrates were observed.
The presence of low levels of nitrites and nitrates suggested (a) that
denitrification was also occurring in the systems; and (b) that the input
of oxygen was insufficient to provide a residual dissolved oxygen concen-
tration in the ditch to prevent the nitrogen losses due to denitrification.
The profiles of the expected and the observed total nitrogen concentrations
in the mixed liquors in the ditches over a period of two months are shown
in Figures 18 and 19. The mass balances for nitrogen indicate that about
65% of the nitrogen added to the ditches was lost due to the mechanisms
of simultaneous nitrification and denitrification occurring in the system.
Oxidation Ditch at the MinkFarm
Experiences in the operation of oxidation ditches to handle poultry wastes
provided basic information on nitrogen control and factors influencing oxy-
genation of highly concentrated wastes. In aerobic biological stabiliza-
tion units with long detention times, the largest portion of the energy
input is utilized to overcome the inertia of any rotor or surface aerator
and to mix the contents of the unit. With the background of the experiences
gained in operating an oxidation ditch, a Jet-Aero-Mix system of aeration
was designed and installed to treat the wastes from the experimental mink
farm (18). From a general maintenance standpoint, this system does not
have the problems of bearings and belt slippage associated with rotor
systems.
75
-------
a*
ZOOOi—
1500-
1000 -
500 -
50
180
210
Figure 16. Fluctuations in nitrogen contents of mixed liquor in oxidation
ditch #1 at Manorcrest Farms.
-------
I500r—
1000
500
TKN
30
60
90
120 150
DAYS
180 210 260
Figure 17. Fluctuations in nitrogen contents of mixed liquor in oxidation
ditch #2 at Manorcrest Farms.
-------
6000 i—
o<
E
o
O
Or
h-
5000
4000
3000
2000
1000
0
0
Figure 18.
1
EXPECTED
10 20 30 40 50
DAVS OF OPERATION
60
70
Expected and observed total nitrogen contents of mixed liquor
in oxidation ditch #1 at Manorcrest Farms.
78
-------
CO
50001—
4000 —
cc
UJ
t
_l
\
z
E
3000
2000
1000
EXPECTED
10
20 30 40
DAYS OF OPERATION
50
60
70
Figure 19. Expected and observed total nitrogen contents of mixed liquor
in oxidation ditch #1 at Manorcrest Farms.
-------
The observations on this treatment system indicated that liquid aeration
systems could easily be incorporated beneath confined minks and the offen-
sive odors from the manure could be eliminated. The oxygen input to the
system was adequate for both odor control and nitrogen conservation. The
characteristics of the mixed liquor examined over a period of six months
are given in Table 21.
The nitrates accumulating in the system could be removed by stopping aera-
tion and allowing the liquor to denitrify. Mass balances computed to assess
the treatment efficiencies indicated that the system was capable of removals
of about 93, 97, and 46 percent, respectively, of nitrogen, BOD and total
solids.
80
-------
Table 21. CHARACTERISTICS OF THE MIXED LIQUOR FROM THE OXIDATION DITCH AT THE MINK FARM
00
Date
16 Nov.
23 Nov.
30 Nov.
8 Dec.
14 Dec.
21 Dec.
28 Dec.
4 Jan.
11 Jan.
18 Jan.
25 Jan.
6 Feb.
8 Feb.
22 Feb.
1 Mar.
4 Mar.
8 Mar.
1973
1973
1973
1973
1973
1973
1973
1974
1974
1974
1974
1974
1974
1974
1974
1974
1974
Total
Solids
(mg/1)
2,350
3,600
4,550
3,673
7,500
9,200
10,135
11,918
12,818
-
15,840
19,230
21,300
22,905
23,588
24,748
COD
(mg/1 )
585
-
1,791
2,534
3,030
3,149
2,938
3,256
4,177
4,739
5,491
5,860
5,785
8,058
9,172
8,264
TKN
(mg/1 )
99.4
108.5
198.8
78.7
179.0
136.0
123.0
126.0
154.0
160.0
118.0
100.8
237.0
277.0
195.0
209.0
210.0
NIVN
(mg/1)
54.6
46.9
114.1
trace
6.3
0
11.2
21.0
14.7
9.8
0
trace
96.6
70.7
9.8
14.0
1.4
N02-N
(mg/1)
7.2
11.5
0.6
trace
trace
trace
trace
1.3
0.3
0.3
0.3
trace
trace
trace
trace
trace
trace
N03-N
(mg/1)
42
165
240
520
650
650
800
950
1,300
1,300
1,700
1,800
1,750
2,150
2,150
2,250
2,150
PH
7.3
5.6
5.6
7.5
5.6
6.2
6.0
6.5
6.5
6.0
6.8
8.0
7.8
5.7
5.7
5.8
6.6
-------
SECTION V
RESULTS OF STUDIES ON LAND APPLICATION OF POULTRY WASTES
APPLICATION RATES AND NITRATE LEVELS IN THE SOILS
Soil nitrate levels as influenced by rate of N application at the three
corn locations and one grass location were determined. Values for the
surface soil are presented in Figure 20 and subsurface values in Figure
21. A higher nitrate concentration resulted with increasing rates of
manure application in both surface soils and subsoils. Surface soil
nitrate levels were higher than subsoil nitrate levels at a given rate of
application. Although the values presented in Figures 20 and 21 are
averages for the 1973 growing season at all locations, they do indicate
that nitrates tend to be concentrated in the surface layer and that the
surface layer of soil contains a concentration of nitrates about twice
that of the subsoil for a given rate of application. Higher nitrate
levels were maintained under the corn plots than under the grass. This
suggests that grasses are heavier feeders on soil nitrates and will result
in lower soil nitrate levels at all rates of application in both the sur-
face soil and subsoil.
This would seem to indicate that grasses could tolerate application rates
higher than 200 pounds N equivalent of poultry waste. This may be true of
oxidation ditch manure which is high in water content and therefore would
distribute the manure salts deeper and more uniformly through the soil
82
-------
OO
CO
20
CROP
O CORN, 3 LOCATIONS
H • GRASS, I LOCATION
e
Q.
Q.
ro
O
15
112
Y=9.I78 + .0253(X)
Y=5.57 + O.I8(X)
_L
448
224 336
NITROGEN APPLIED, kg/ha
Figure 20. Average growing season NCL level in the surface soil 0-23 cm as
influenced by several rates of spring applied ODML on corn and
grass, 1973. Average of four studies.
-------
20h
CROP
O CORN, 3 LOCATIONS
• GRASS, I LOCATION
00
E
o.
Q.
rO
O
O1
O
Y= 7.3I4-.OI2CX)
Y= 1.64-i-.021 (X)
224 336
NITROGEN APPLIED, kg/ha
448
Figure 21. Average growing season NCL levels in the subsoil, 24-46 cm, as
influenced by several rates of spring applied ODML on corn and
grass, 1973. Average of four studies.
-------
profile. However, since plowing or soil incorporation is not the practice
with grass sods other forms of poultry wastes would not move readily into
the soil and would result in too high concentrations of salts in intimate
contact with the above-ground portion of grasses. This could result in
injury or death of the plant.
Nitrate levels in both the surface soil and subsoil fluctuate throughout
the growing season (Fig. 22). Values under both corn and grass are shown.
Again, nitrate levels in the soil under grass are lower than those under
corn. Values are higher during June and July in the surface soil. This
is not surprising because soil conditions, especially moisture and temper-
ature, were favorable for mineralization of N. Subsoil nitrate levels were
highest in June under corn. This is explained by the fact that soil con-
ditions favored mineralization of N and that the corn plants were young
and absorbing small quantities of N. Rainfall during the period of rapid
N mineralization and low plant uptake of N can result in rapid downward
movement of nitrates into the subsoil. Although it is difficult to predict
exact mineralization rates of N from manure, generalizations can be made
regarding safe application rates (19).
SURFACE RUNOFF LOSS, FIELD STUDIES
The bar graphs in Figures 23 and 24 show average growing season nitrate
and ammonium values in surface soil and subsoil as influenced by source,
rate of application and Spring vs. Fall application. Data are presented
in these figures from the two locations, Poultry Farm and Aurora Research
Farm. Nitrate levels in the surface soil and subsoil increased with
increasing rates of poultry manure. Higher levels were recorded with
Spring applications of both fresh and oxidation ditch poultry manure than
with these materials applied in the Fall. This suggests that nitrates
have been lost from the Fall applied material. In addition, these nitrates
85
-------
10
e
Q.
a.
rO 0
O
15
10
El CORN (3 LOCATIONS)
D GRASS (I LOCATION)
[71
APR
XI
SURFACE 0-23 cm
71
SUBSURFACE 24-46 cm
MAY JUNE JULY
OCT
Figure 22. N03 level in the soil according to month of growing season and
crop grown. Average of four studies.
86
-------
e
o
ro
f\J
i
O
N03 L.S.D. at .05 = 4.68
IMH4 L.S.D. at .05= 1.48
20-
_J
o
E « I0
0. O
a. <
u.
<3- CE
-
—
I/I
—
v~\
(/
"
7
/
f/j
—
M
p-j
N
00
-q
QC
O
K) O
O to
OJ
20-
N03 L.S.D. at .05=4.09
NH4 L.S.D. at .05= NONE
O 10
(/) ' w
CD
y-\
-
n
RATE OF N, kg/ha °
0
—
H 11 n
12 224 112
XX XX
0
••••
0
12 224
v v v
TIME SPRING I-ALL^ ^ SPRING
v y N v ^
SOURCE OXIDAT
ON DITCH FRESH RAW
Figure 23. Average growing season NOg + NH4 in the soils as influenced by
the rate, form and time of poultry manure application. Poultry
farm runoff study
-------
00
oo
e
o
ro
C\J
o20_
L.S.D. at .05 = 5.25ppm
QNH4 L.S.D. at .05=NONE
o
CO
o ' 0
o:
r>
CO
n
—
n
PTJ
—
n
—
n
"""""
171
n
nn
i — i
E
o
DN03 L.S.D. at .05 = 4.03
QlMH4 L.S.D. at .05= NONE
20-
eg
_i
5 10
CO
CD
r>
tn
R
RATE OF N 0
n
0 Hn
n
12 224 ^ 112 224 .
>"s. /X
n
H
12 224 ^
PI
R
12 224 x
V V V V
TIME v SPRING FALL /\ SPRING FALL /
v V
SOURCE OXIDATION DITCH FRESH RAW
Figure 24. Average growing season N03 + NH^ in the soil as influenced by the
rate, form and time of application of poultry wastes. Aurora Farm
runoff study, 1973.
-------
have probably moved beyond the rooting depth of crop plants and have
reached the groundwater. There was very little difference in the amount
of nitrates found in both surface soils and subsoils as a result of
source of manure (Fig. 23 and 24). Ammonium levels at the two locations
and two soil depths were not greatly different from the check plots.
There were no significant volume differences in water runoff at either of
the two locations except as influenced by slope. Runoff water collected
during the growing season indicated no significant losses of nitrates,
ammonium, total soluble phosphorus or soil sediments due to manure treat-
ment (Tables 22 and 23).
There were significant yield increases of dry shelled grain as a result of
manure applications. Application rates of manure to supply 112 and 224 kg
N/ha resulted in increases above the treatment which did not receive manure.
These trials suggest that either application rate of manure would produce
grain yields above check treatments. Nitrogen would be released at a rate
to sufficiently meet the N requirements of the corn plant but not cause
excessive nitrate losses that would contaminate the groundwater. With higher
manure application there was an increased uptake of N by the corn plants
(Fig. 25 and 26). Although these two runoff studies were conducted on
different soils at locations about 25 miles apart, the general conclusions
are the same.
POULTRY MANURE RESIDUE STUDY
A study was initiated in 1971 to determine residual or carryover effects
of poultry manure applied to land planted to corn. Corn was planted and
harvested the year of manure application. In addition, corn was planted
and harvested with one, two and three years intervals following the year
of application. Measurements were made on stover and grain yields as well
89
-------
Table 22. WATER, SEDIMENT AND CERTAIN NUTRIENTS LOST IN
RUNOFF9 - AURORA FARM RUNOFF STUDY, 1973-1974
(O
o
Source of Nitrogen -
Time of Application -
Nitrogen Rate -
Runoff
£ NM
^ N03N
^ Ortho P
£ Tot. Sol. P
' Soil Loss
§ O.M.
-3 Total Silt Phos.
Total Silt N
Runoff
^ NM
,_ N03N
Q- Ortho P
J Tot. Sol. P
^ Soil Loss
" O.M.
o Tot. Silt Phos.
Total Silt N
Runoff
NM
£ N03N
•- Ortho P
£ Tot. Sol. P
o Soil Loss
-------
Table 22 (continued). WATER, SEDIMENT AND CERTAIN NUTRIENTS LOST IN
RUNOFF9 - AURORA FARM RUNOFF STUDY, 1973-1974
c
3
%-
Q-
oo
I—
>
o
o
o
3
o
Source of Nitrogen -
Time of Application -
Nitrogen Rate -
Runoff
NH^N
N03N
Ortho P
Tot. Sol. P
Soil Loss
O.M.
Total Silt Phos.
Total Silt N
Runoff
NH^N
N03N
Ortho P
Tot. Sol. P
Soil Loss
O.M.
Tot. Silt Phos.
Total Silt N
Runoff
NHi,N
N03N
Ortho P
Tot. Sol. P
Soil Loss
O.M.
Tot. Silt Phos.
Tot. Silt N
M3
Kg /ha
Kg/ha
Kg/ha
Kg/ha
Kg/ha
Kg/ ha
Kg/ ha
Kg /ha
M3
Kg/ha
Kg/ha
Kg/ha
Kg/ha
Kg/ha
Kg/ha
Kg/ha
Kg/ha
M3
Kg/ha
Kg/ ha
Kg/ha
Kg/ha
Kg/ha
Kg /ha
Kg/ha
Kg/ha
Check
0
41.3
0.037
0.190
0.003
o.on
561.
26.86
0.476
1.352
14.4
0.022
0.134
0.000
0.008
148.6
7.04
0.125
0.403
103.8
0.034
0.291
o.on
o.on
3795.
112.
2.70
6.85
Fresh Raw
Spring
100
44.2
0.030
0.213
0.008
o.on
428.
32.83
0.456
1.438
7.6
0.056
0.20
0.003
0.003
56.3
3.61
0.055
0.166
101.8
0.067
0.336
o.on
0.022
4471.
108.
3.00
7.27
200
72.1
0.097
0.549
0.026
0.034
1432.
65.48
1.191
3.339
4.7
o.on
0.168
0.000
0.000
78.7
3.55
0.069
0.183
166.5
0.325
0.672
0.022
0.032
3295.
150.
2.74
7.71
F
100
58.8
0.048
0.433
0.008
0.011
1699.
61.17
1.291
3.428
52.4
0.482
0.470
0.213
0.258
257.6
15.13
0.240
0.713
117.2
0.022
0.347
0.011
o.on
1953.
84.
1 .59
4.40
all
200
23.6
0.019
0.109
0.008
o.on
228.
11.83
0.200
0.579
40.8
0.157
1.053
0.090
0.109
41 .8
3.52
0.047
0.151
54.5
0.022
0.302
o on
w • \J i i
0.022
1790.
64
V/™ •
1 36
1 t \J\J
3.57
Ave. of 3 replications
-------
Table 23. WATER, SEDIMENT AND CERTAIN NUTRIENTS LOST IN RUNOFF -
POULTRY FARM RUNOFF STUDY, 1972-1973a
CO
to
Nitrogen Source -
Time of Application
Nitrogen Rate -
CM Runoff
o^ NHi+N
" N03N
-p Ortho P
o Total Sol . P
i Soil Loss
QJ Organic Matter
§ Total Silt Phos.
^ Total Silt N
Runoff
i-» NHijN
? N03N
• Ortho P
£ Total Sol. P
Soil Loss
' Organic Matter
c Total Silt Phos.
^ Total Silt N
Oxidation Di
M3b
Kg/ ha
Kg/ ha
Kg/ ha
Kg/ ha
Kg/ ha
Kg/ ha
Kg/ ha
Kg/ ha
M3
Kg/ ha
Kg/ ha
Kg/ha
Kg/ ha
Kg/ ha
Kg/ ha
Kg/ ha
Kg/ ha
Check
0
53.5
.045
1.90
.011
.034
1327.
27.58
.93
1.08
19.7
.054
.292
.009
.011
190.
6.
.13
.36
Spring
100
53.5
.056
2.93
.034
.034
3615.
99.15
2.52
6.27
36.4
.050
.430
.017
.022
806.
31.61
.64
1.71
200
28.8
.034
.627
.011
.011
1363.
36.01
.94
.011
8.4
.188
.174
.009
.034
10.
.57
.01
.03
tch
Fall
100
._
—
—
—
—
--
—
—
—
17.4
.025
.144
.009
.022
235.
7.11
.17
.43
Fresh Raw
Spring
100
93.5
.134
3.18
.011
.034
1267.
47.07
.97
.045
43.7
.097
.550
.011
.022
1107.
37.59
.83
2.16
200
43.2
.045
.77
.011
.011
486.
18.20
.37
.011
37.5
.129
.480
.015
.022
380.
12.06
.28
.72
Average of 4 replications
3Six selected storms
-------
MANURE NITROGEN APPLIED
CO
o
JC
CT 89.6
z~
LJL
0 67.2
LU
h-
0.
^ 44.8
Q-
O
CE
O
22.4
^--"^
• CHECK
0112
©224
A 112
A 224
D 112
Q 224
"•112
* 224
OXIDATION
OXIDATION
OXIDATION
OXIDATION
FRESH RAW
FRESH RAW
FRESH RAW
FRESH RAW
SPRING
SPRING
FALL
FALL
SPRING
SPRING
FALL * ^^
FALL ^*^"^ A
A © ^>>^*
ED *,§
Y=-2.53-KOI65X © 0^°
_DRY SHELLED CORN ^^ °
> £1 O Q
A^^ r^. u ©
^. A ^^^
^^* ^ . j^»
^
^r
l
Y= 2.82 + .0068X
STOVER DRY MATTER
1 1
1120 2240 3360 4480
DRY MATTER PRODUCED, kg/ha
Figure 25. Relationship of nitrogen uptake in grain and stover to dry matter
produced. Aurora Farm runoff study, 1973.
-------
CD
0
U-
o
LU
134
112-
89.6
67.2
JViANURE NITROGEN APPLIED, kg/ha
'•CHECK
OOXIDATION 112 SPRING
A OX I DAT ION 224 SPRING
_AQXIDATION 112 FALL
a FRESH RAW 112 SPRING
•FRESH RAW 224 SPRING
Y=-26.7 + .0228X
DRY SHELL CORN
Q.
O
cr
o
44.8-
22.4-
Y= 8.38-K0054X
STOVER DRY MATTER
0
Figure 26.
3360 4480 5600
DRY MATTER PRODUCED, kg/ha
Relationship of nitrogen uptake in grain and stover to dry matter
produced. Aurora Farm runoff study, 1973.
6720
-------
as the N content of the stover and grain. Soil samples at 0-23 cm and
25-45 cm depth were taken and nitrate content determined.
The average nitrate content of soils for the 1973 growing season according
to treatment is presented in Figure 27. Nitrate levels under manure
treated plots were higher in the surface soil than the subsoil for a
given treatment. The highest nitrate level in the subsoil occurred when
commercial fertilizer N had been applied. Subsoil nitrate levels under
manure treated plots were not significantly different from the check or
no manure treatment. This indicates that very little nitrate from manure
at the 112 and 448 kg N/ha treatment moved into the subsoil.
Corn grain yields for the 1972 and 1973 growing season have been averaged
according to four of the treatments (Fig. 28). The 1974 grain yields
are presented in Figure 29. In 1974, the only treatment receiving nitro-
gen was the commercial fertilizer treatment. All others were residuals
of various manure treatments with intervals of one, two, or three years
since manure application. From these data on corn yields according to
rate and year of application, one can draw inferences regarding the
release of N from poultry manure. About 50 percent of the N in poultry
manure, either oxidation ditch or fresh manure, is available the first
year. Of the remaining N in the manure, only very small amounts are
mineralized in succeeding years and available for plant use (Fig. 29).
As was the case with the runoff studies, there was a good relationship
between corn dry matter produced and crop uptake of N (Fig. 30).
Earlier results and conclusions from this study have already been
published (5).
95
-------
e
o.
o:
o
e
o
ro
CM
• 20
o
LU
o 10
u_
CC
0
E
°20
CD
i
CVJ
O 10
00
ID
cn
0
L.S.D. at .05 = 7.87
NH4 L.S.D. at ,05 = NONE
0
12
448
45
POULTRY MANURE
CHEM PERT
NITROGEN APPLIED, kg/ha
soil during 1973 growing seas
by rate of ODML and commercial fertilizer. Aurora Farm residue study, 1973.
Figure 27. Average NO + NH, in the soil during 1973 growing season as influenced
96
-------
6250
D1971 TREATMENT ONLY
UJ
-------
CD
ao
6250
UJ
oc
3*
»o
r 3750
o
.c
*>*.
en
o:
g 2500
Q
LU
LU
X
C/)
250-
0
TREATMENT APPLIED
f^ CHECK
1971
1971, 1972
1971,1972, 1973
[1111971,1972,1973,1974
L.S.D at .05=1000 kg/ha
RATE OF N, kg/ha 0
56
112
224
448
896
SOURCE POULTRY MANURE
Figure 29. 1974 yields from poultry waste residue study. Aurora, New York.
90
CHEM
FERT
-------
to
to
o
.c
^
cn
O
LU
*:
<
h-
Q.
Q-
O
CC
O
89.6
67.2
44.8
22.4
NITROGEN APPLIED, kg/ha
• CHECK
0112 OXIDATION DITCH MANURE
"448 OXIDATION DITCH MANURE
a48 COMMERCIAL FERTILIZER
Y=-I.28-K0207X
DRY SHELLED CORN
O
O
Y= -1.17-h.009 X
STOVER DRY MATTER
1120
224O 3360 4480
DRY MATTER PRODUCED, kg/ha
Figure 30. Relationship of nitrogen uptake in grain and stover to dry matter
produced. Poultry waste residue study. Aurora, New York, 1973.
-------
GRASS RESPONSE TO APPLICATIONS OF POULTRY MANURE
Poultry manure and chemical fertilizers were used as a source of N on
orchard grass and bromegrass. This study was an attempt to evaluate the
timing and rate of application of poultry manure as an effective source
of N. Oxidation ditch manure, fresh manure without litter and commercial
fertilizer N were applied the first weeks of November 1972 and May 1973.
The two manure sources were applied at rates of 0, 56, 112, and 224 kg
N/ha. Commercial fertilizer was applied at the rate of 56 kg N/ha.
Yields of orchard grass according to treatment are presented in Figure
31. Orchard grass responded well to all manure treatments applied in both
spring and fall. This grass did not respond well to commercial fertilizer
N.
Bromegrass (Fig. 32) responded best to the 224 kg N/ha rate at each time
of application and each source except for the spring applied fresh poultry
manure. These grass yield responses to various rates and time of appli-
cation indicate that perennial forages such as orchard grass and brome-
grass can utilize N supplied by either oxidation ditch or fresh poultry
manure. Either fall or spring applications would not only benefit the
forage but provide flexibility in terms of time to dispose of the manure.
It can be generalized that grass response favored fall applications.
The relationship between N uptake and dry matter produced for orchard grass
and bromegrass is presented in Figures 33 and 34 respectively.
100
-------
9000r
8000
CT
UJ
7000
6000
cc
Q
5000
o1
RATE
SOURCE
TIME
r
0
CHECK
56 112 224
OXID.
DITCH
56112224
FRESH
RAW
56
CHEM
FERT
0
CHECK
56112224
OXID
DITCH
56112224 56
FRESH CHEM
RAW FERT
FALL
SPRING
Figure 31. The effect of source, rate and time of application of poultry manure
and commercial fertilizer on the yield of orchard grass (2 cuttings)
L.S.D.@ .05 = 1255. Aurora Farm grass study, 1973.
-------
7000
6000
UJ
5000
o:
Q
4000
0L
RATE 0
SOURCE CHECK
TIME
56112224 56112224 56
0X1D. FRESH CHEM
DITCH RAW PERT
FALL
0
CHECK
56 112224
OXID
DITCH
SPRI
56 112224 56
FRESH CHEM
RAW FERT
NG
Figure 32. The effect of source, rate and time of application of poultry manure
and commercial fertilizer on the yield of orchard grass (2 cuttings)
L.S.D.0 .05 = 1939. Aurora Farm grass study, 1973.
-------
o
to
NITROGEN RATE, SOURCE AND TIME OF APPLICATION
OXIDATION DITCH
MANURE, kg/ha
280
224
O
uj 168
Q.
O
tr
o
11
56
O 56]
01 12,
FALL
0 56)
® 112? SPRING
1
FRESH RAW
MANURE, kg/ha
a 56)
QM2> FALL
*224)
0 56)
0M2l SPRING
COMMERCIAL
FERTILIZER, kg/ho
A 0 CHECK
• 56 FALL
•56 SPRING
0
Y= -7.065 + .027 X
ORCHARD GRASS DRY MATTER (2 CUTS)
i
4480
Figure 33.
5600 6720 7840
DRY MATTER PRODUCED, kg/ha
8960
Relationship of nitrogen uptake in orchard grass to dry matter produced.
Aurora Farm grass study, 1973.
-------
O
280
0
1,224
.s:
"ZL
uJ
0 168
LU
|
p_
Q.
^ 112
a.
o
or
o
56
NITROGEN RATE,
OXIDATION DITCH
MANURE, kg/ha
-0 56
0112 FALL
^224
0 56
_®II2 SPRING
A 224
.......
^
-f*-
i
SOURCE
FRESH
AND TIME OF APPLICATION
RAW COMMERCIAL
MANURE, kg/ha FERTILIZER, kg/ha
a 56
a 112
*224
0 56
H 112
®224
®~^
*^~*"^ •
A 0 CHECK
FALL • 56 FALL A
• 56 SPRING
SPRING ^^^-^^"
IT^T^D
®*^^*
-***-' A
Y= -24.95 + . 03 X
BROME GRASS DRY MATTER (2 CUTS)
1 1 I 1
4480
5600 6720 7840
DRY MATTER PRODUCED, kg/ha
8960
Figure 34.
Relationship of nitrogen uptake in bromegrass to dry matter produced.
Aurora Farm grass study, 1973.
-------
SECTION VI
DISCUSSION OF EXPERIMENTAL RESULTS
GENERAL
Unless livestock wastes are properly stabilized and managed, they may pose
environmental problems. Because land is the ultimate disposal medium for
livestock wastes, there is no need to process the wastes to obtain degrees
of stabilization comparable to those of effluents discharged to surface
waters. Livestock waste treatment objectives will be based on other
factors. Land application rates can be a controlling factor whether land
is used for crop cultivation or for disposal.
Uncontrolled nitrogen losses have been reported in animal waste stabiliza-
tion systems (20-27). The results of our investigations on aerobic stabili-
zation of animal wastes confirm these observations. Investigations of this
project also indicated that it is possible to control the losses of nitrogen
by manipulating the operation of the oxidation ditch.
Based on the project evidence collected in the laboratory and pilot plant
studies on the effect of some factors influencing the stabilization of
animal wastes, some design criteria have been developed. These criteria
have permitted the design and operation of a waste stabilization system for
a mink farm and have-assessed the performance of two full scale stabili-
zation systems in operation at the poultry farms. The continued observation
105
-------
on the full scale systems also have permitted better identification of
inherent managerial problems associated with the operation of stabili-
zation systems.
These studies have also been useful in the development of management
models for animal waste stabilization including nitrogen control (28).
It is now possible to alter the nitrogen removal efficiency of the
stabilization system without impairing the efficiencies of removal of
total solids and COD. Differences in nitrogen losses from the stabili-
zation systems can be achieved by varying oxygen inputs to the system
without significantly altering the nitrifying activity in the system.
The observed nitrogen losses were found to be the lowest when the system
was kept aerobic at all times; however, these losses can be increased
by any of three approaches: (a) denitrify the mixed liquor in a separate
solids separation unit without stopping the aeration in the oxidation
ditch, (b) denitrify the mixed liquor in situ by stopping the aeration
for an optimal time, which is related to the condition at which the oxi-
dation ditch was operating, and (c) manipulate the design of the rotor
such that there is an adequate dissolved oxygen concentration for some
distance from the rotor to accomplish nitrification and it is absent in
the remainder of the ditch to achieve denitrification.
NITROGEN CONSERVATION
It is difficult to operate a waste treatment system without losing some
nitrogen. Anoxic pockets and the microaerophilic and facultative condi-
tions prevailing at the floccular level of the mixed liquor enhance deni-
trification and generally precluded the possibility of conserving all the
nitrogen entering the system. In addition, some ammonia volatilization
could occur before nitrification occurs. Even if a significant concentration
106
-------
of dissolved oxygen is maintained in the mixed liquor, some loss of nitrogen
will occur. If conservation of nitrogen is the objective, such losses
should be minimized by operating the ditch appropriately.
The results of the first two modes of operation discussed in this paper
indicate the opportunities that exist for controlling nitrogen losses.
Liquid aeration systems operated either as continuously filled reactors
without wasting of mixed liquor (mixed aerobic holding tanks), or as
continuous flow devices exhibited only a 30% loss of the input nitrogen.
Aerobic holding tanks for poultry wastes should be kept below a total
solids concentration of 2% since oxygen transfer becomes less efficient
beyond that concentration (18). In the continuous flow operation, solids
concentration can be controlled at an optimal level for maximum oxygen
transfer. Nevertheless, even at a total solids concentration of -5000 mg/1
at which Op transfer efficiency was not impaired in the mixed liquor and
D.O. concentrations were generally above 5 mg/1, about 30% of the total
nitrogen input was lost. Thus in oxidation ditches operating under highly
aerobic conditions, it may be difficult to conserve more than 70% of the
nitrogen fed into the system. However, it may be possible to conserve
more nitrogen than was possible in the current study by: (a) minimizing
the probability of occurrence of anoxic conditions in the mixed liquor
suspended solids by efficient mixing and maintaining a high D.O. concen-
tration in the ditch, and (b) operating the ditch at a low mixed liquor
total solids concentration (0.5 - 1.0%) and incorporating frequent removal
of the mixed liquor.
PARTIAL NITROGEN CONSERVATION
Assuming that crop growth is integrated with the disposal of oxidation ditch
effluent on land, it may be desirable to remove only a fraction of the
nitrogen present in the mixed liquor if the land available for disposal is
107
-------
limited. In such situations only partial conservation of nitrogen may be
sufficient to meet the suggested or required nitrogen application rates.
From the results obtained in this study, this objective can be accomplished
by programming in situ denitrification schedules, while allowing the ditch
to operate as a continuous flow device. For example, in Operational Mode II,
the 62.1% of the total nitrogen that passed through the oxidation ditch
with the effluent (Table 14) could have been made less, if the duration of
the continuous flow-through periods was curtailed and periods of denitrifi-
cation followed by nitrification of a shorter duration repetitively fol-
lowed one another. However, such denitrification periods can only be intro-
duced after a continuous flow-through period when N03-N is present in the
mixed liquor, since without NCL-N in the mixed liquor,denitrification can
not take place. Thus careful manipulation and monitoring of the nitrifi-
cation phase of the oxidation ditch operation and judicious introduction
of a denitrification phase after each of the nitrification phases is needed
to achieve the desired nitrogen removal. The amount of nitrogen removal
depends on the number of nitrification-denitrification phases during a
given period of the oxidation ditch operation.
Partial removal of nitrogen from ODML can also be accomplished by practicing
intermittent rotor aeration. Varied degrees of nitrogen removal can be
accomplished by manipulating the period of rotor aeration. Thus for example*
higher nitrogen removal was obtained in an operation having 12 hr rotor-
aeration/day than in 13 to 24 hr rotor-aeration/day.
MAXIMUM NITROGEN REMOVAL
The results of this study indicated that a very high percentage of nitrogen
removal, up to 90%, of input nitrogen, can be accomplished. This can be
achieved by including a denitrification-settling tank and recycling of the
supernatant to the oxidation ditch or by manipulating the aeration of the
108
-------
mixed liquor. An advantage with recycling the supernatant is the conser-
vation of water.
Previous studies (21) showed that nitrifying organisms can withstand pro-
longed anaerobiosis, and can easily nitrify poultry waste mixed liquor
when once aerobiosis is restored. Taking advantage of this observation,
an operational mode for the oxidation ditch was studied. In this mode
(Mode IV), the mixed liquor was aerated only partially in a day to achieve
nitrification. It was then subjected to anaerobiosis during the remain-
ing portion of the day to achieve the denitrification of the oxidized
nitrogen formed during the aerobic phase. This mode of operation also
provided an opportunity for removing the end products of ammonia oxida-
tion, thereby relieving any inhibition of nitrification due to enzyme
repression by these end products. By resuming aeration of the mixed liquor
after the anaerobic period, nitrification once more occurred and the
oxidized nitrogen was removed in another anaerobic phase. Thus by mani-
pulating the denitrification phases, it is possible to accomplish variable
losses of nitrogen as well as maximum nitrogen control.
The effect of varying periods of aeration on the nitrogen losses from the
oxidation ditch are shown in Figure 35. These results suggest that it is
possible to achieve varying degrees of nitrogen removal in the range of
30 to 90 percent, by suitably adjusting the period of aeration and in situ
denitrification in the oxidation ditch. In view of the results of the
current study, the following nitrogen losses can be expected depending on
the mode of operation of the oxidation ditch (Table 24).
Other modes of operation are possible by using combinations of the above
modes. It should be possible to achieve different degrees of nitrogen
removal with different combinations of the above modes of operation by
controlling the effective denitrification time without seriously affecting
the performance of the nitrification phase.
109
-------
5 10 15 20 25
DAYS
Figure 35. Aeration period and nitrogen losses in an oxidation ditch.
110
-------
Table 24. SUMMARY OF EXPECTED NITROGEN LOSSES IN DIFFERENT
MODES OF OXIDATION DITCH OPERATION
Mode of operation
1. Continuously filling device
2. Continuous flow operation with
jjn situ denitrification
3. Continuous flow operation and recy-
cling of supernatant via a settling-
denitrification tank
4. Semi-continuous or continuous operation
with partial rotor aeration,
(12 to 16 hrs/day only)
Expected % of TN loss
-30
130 depending on the number
of U[ situ denitrifica-
tion time phases
-90 less % of removals can be
achieved by prolonging
the aerobic phase and
curtailing the denitri-
fi cation phases
COD REMOVAL IN NITROGEN CONTROLLING SYSTEMS
Approaches that have achieved the nitrogen control objectives can not justi-
fiably be applied to agricultural waste treatment systems unless other
environmental objectives such as odor control and some degree of waste
stabilization also are realized. The results of this study indicated
that odor control was achieved in all the modes of operation. Odor was
not perceived even when the nitrified mixed liquor was subjected to anoxic
conditions for about two to three weeks.
Ill
-------
Chemical oxygen demand balances were computed for all modes of the oxi-
dation ditch operation and summarized in Table 25.
Table 25. COD LOSSES IN AN OXIDATION DITCH
DURING VARIOUS MODES OF OPERATION
Mode of operation % COD loss
I. Continuously filling mode with 62.5
continuous rotor aeration
II. Continuous flow mode with in situ
denitrification
a) filling periods
b) flow-through periods 34.5 } 50.9
c) in situ denitrification periods
d) COD loss via effluent
III. Continuous flow mode with recycling 53.0
of supernatant from a settling tank
IV. Continuous filling mode with curtailed
rotor aeration
a) 12 hrs/day 59.0
b) 16 hrs/day 51-4
COD removals of 50-60% were achieved irrespective of the mode of operation
of the ditch used to control nitrogen. Although high COD removals are
not required for the disposal of treated wastes on land, approaches pre-
sented in this study for the control of nitrogen do provide other benefits
such as accomplishing odor control and waste stabilization.
112
-------
MANAGEMENT MODEL FOR WASTE STABILIZATION
Conventional agricultural practices have placed little emphasis on the
management of animal wastes. With the increasing public concern towards
preservation of environmental quality and the recently imposed restric-
tions on disposal of animal wastes, proper management of manures has assumed
greater importance. There is no one type of waste stabilization and manage-
ment system that will be satisfactory for every type of production facility.
Management objective is a major factor in the choice of the system. The
choice of a stabilization system should be viewed as the last step in the
choice of alternatives for handling animal wastes. If possible, the animal
production facility should be located away from the suburbia or land areas
having minimal resources for safe disposal of manure. By proper choice of
housing for animals, and scheduling of waste removal, it may be possible
to mitigate the pollutional problems. If this initial care in planning
the production facility is not adequate to prevent environmental problems,
then a stabilization system may become a necessary addition to the waste
management system.
The objectives of stabilization will be determined by the nature of con-
straints. If the production facility is located near suburban housing, odor
control is an important objective of waste management. If this facility is
away from the suburbia, there may be no need to control odors, and the
manure may be disposed of by spreading on land. If sufficient land is avail-
able to grow grains for feeding animals, it would be logical to use the
manure to fertilize the land since fertilizers are in short supply. If the
facility is near a housing area and adequate crop land also is available, the
objectives of stabilization would be (a) control odor, and (b) maximum conser-
vation of nitrogen. If on the other hand, adequate land is not available to
113
-------
spread the manure, removal of the excess nitrogen instead of nitrogen con-
servation, would be the nitrogen control objective.
In view of the observations on the performance of oxidation ditches, it would
appear that waste stabilization in an oxidation ditch would perhaps be the
most feasible means of achieving the objectives. The performance of the
oxidation ditch is largely dependent on the oxygen inputs to the system.
Using the available data, a mathematical model has been developed (29) to
describe the oxygen requirements for (a) odor control; (b) nitrogen
removal; and (c) maximum nitrogen conservation.
In an aerobic biological treatment system, a reasonably accurate estimate
of the amount of oxygen-demanding material is necessary in order to properly
size the aeration equipment. There are two important groups of oxygen-
demanding material in poultry waste. First, oxygen is needed to oxidize
the organic carbon which is present in the waste material. This carbon-
aceous oxygen demand can be estimated by the chemical oxygen demand (COD)
if nitrite ions are not present in the wastes. In addition to this car-
bonaceous demand, oxygen also may be needed to oxidize the ammoniacal
nitrogen resulting from the hydrolysis of nitrogenous organic matter.
Raw poultry waste contains nitrogen mainly in the form of polypeptides,
amino acids and uric acid. Ammonification is carried out by a diverse
group of microorganisms. It is a process whereby the organic nitrogen
compounds are metabolized to ammonia primarily by the deamination of the
amino acid residues and the hydrolysis of uric acid. If sufficient
oxygen is present in the system, autotrophic nitrifying bacteria will
develop and oxidize NH. to nitrite and nitrate. For every gram of ammonium
nitrogen oxidized to NO", 4.57 g of oxygen are required.
114
-------
The total amount of oxygen which must be supplied to the mixed liquor
will depend upon the objectives of stabilization. If the system is
to be operated only to control odor, then the rotor may be designed
to supply only sufficient oxygen to meet the carbonaceous demand.
On the other hand, if the system is used to minimize nitrogen losses,
enough oxygen must be supplied to meet both the carbonaceous and the
nitrogenous demands. This same quantity of oxygen may also be
required for maximum nitrogen removal since good nitrification is a
prerequisite to subsequent denitrification.
In a completely aerobic biological system, oxygen is used as the
terminal electron acceptor. Under anaerobic conditions, organic carbon,
carbon dioxide, nitrate ions, and sulphate ions will be used as terminal
electron acceptors. The production of reduced organic compounds such as
ammonia, sulfides, mercaptans, amines, organic acids and methane will
result. Certain of these compounds are responsible for the undesirable
odors released under anoxic conditions. The amount of oxygen which must
be supplied to prevent anaerobiosis is assumed to be that quantity required
to meet the demand of the oxidizable COD. Not all of the biodegradable
COD will utilize oxygen since some of it will be incorporated into cell
mass. At the ideal steady state conditions which have been assumed in this
model, organic matter will not accumulate in the system. Therefore the
amount which is oxidized at steady state conditions is equal to the dif-
ference between the amount added in the raw waste and the amount present
in the mixed liquor. This can be expressed by the following equation:
fc . O - 0. - 0 (15)
where f = fraction of the influent organic matter which is oxidized
Q
0. = rate of addition of organic matter (mass/time)
0 = rate of removal of organic matter (mass/time).
115
-------
The oxidation of organic carbon can be expressed directly as an oxygen
demand. Each unit by weight of COD which is oxidized requires one unit
weight of oxygen. The following equation, derived from the mass balance
approach above, was used in this study to determine the rate at which
oxygen must be supplied to the mixed liquor for odor control:
R = f .S.n (16)
V*r
where R = microbial oxygen demand, (mass/time);
S = rate of COD loading to the ditch, (mass/bird-time)
n = number of birds.
Oxygen Demand for Nitrogen Control
In an aerobic biological treatment system, nitrogen may be removed by
ammonia desorption or by nitrification followed by denitrification. The
latter is the more effective and controllable method for the removal of
nitrogen in livestock wastes. The most efficient means of storing nitro-
gen in a biological system is to oxidize the ammoniacal nitrogen to
nitrate ions and to avoid subsequent denitrification. Consequently, if
the treatment objective is either to remove nitrogen or to conserve
nitrogen, enough oxygen must be supplied to meet both the carbonaceous
as well as the nitrogenous demand. The amount of nitrogen which will
exert an oxygen demand is assumed to be the biodegradable fraction of
TKN. A small quantity of this fraction will be incorporated into cell
growth. Since only a relatively small portion of the large supply of
ammoniacal nitrogen available in animal wastes will be used in cell synthesis;
however, the assumption is valid for the purposes of this study.
The total oxygen demand is the sum of carbonaceous and nitrogenous
demands and is expressed in the model by the following equation:
116
-------
R = n (fcS * 4.57 fNSN) (17)
where f^ = fraction of TKN which is biodegradable
SN = rate of TKN loading to the ditch, (mass/bird-time).
Power and Oxygen Requirements
The quantity of power required to achieve adequate aeration is a function
of the amount of oxygen demanding material added to the ditch and of the
management objectives. Since the efficiency of oxygen transfer decreases
as the total solids concentration increases, power requirements for the
same oxygen input will increase with increases in the solids concentration
of the mixed liquor. More oxygen is needed for nitrogen removal and nitro-
gen conservation than for mere odor control. It is useful for the designer
and operator of the waste management system to know what the economic
trade-offs will be between these objectives.
The power requirements for achieving odor and nitrogen control objectives,
at different solids concentration in the ODML are shown in Figure 36.
These data were calculated using the mathematical models described in this
report, and illustrate the differences in power requirements for achieving
the two objectives. The power required for achieving odor control is the
energy required to drive the rotor to supply the oxygen needed to meet the
carbonaceous oxygen demand. The power requirements for achieving nitrogen
control are higher as more oxygen input is necessary to oxidize all NH^
to nitrates.
These power requirements are the maximum needed to achieve the stated
objectives at different solids concentrations. It is important to identify
the few assumptions that were made to calculate the data presented in
117
-------
Figure 36. It was assumed [i] that all the available ammoniacal nitrogen
is oxidized to nitrates; (ii) that no losses of nitrogen due to ammonia
desorption occur during stabilization; and (iii) that no losses due to
denitrification occur and a residual dissolved oxygen concentration of
2 mg/1 is always maintained in the system. If these assumptions are not
valid, then the estimates will differ.
During the oxidation of NH, to NO", hydrogen ions are generated, and as a
result, the pH value of the system decreases (Equation 1). The pH value
of the nitrifying stabilization system is generally near 7.0 or even
slightly below 7.0. Under these conditions, nitrogen losses due to ammonia
desorption become insignificant. In a non-nitrifying system, significant
losses of nitrogen due to ammonia volatilization occur and it is very
difficult to control such losses.
When the oxygen input to the stabilization system is stopped, denitrifica-
tion of the oxidized forms of nitrogen occur. Even though the actual
reactions involved are complicated, they can be summarized by:
2 N0~ + 10H+ *- N2* + 4H20 + 20H~ (18)
2 NO;, + 6H+ ^ N2t + 2H20 + 20H~ (19)
The reaction is carried out by faculative heterotrophic organisms which use
the nitrate and nitrite as electron acceptors and organic carbon as an
energy source. The process of denitrification represents a further means
of decreasing COD in the stabilization system.
One proposed means of establishing a nitrifying-denitrifying system is to
cycle rotor operation on a regular and daily basis described in this
report. Data indicate that nitrogen losses as high as 90% of the input
could be achieved with this mode of rotor operation.
118
-------
60
O
a:
CD
o
o
o
50
40
H £30
cr
20
LU
10
a: <
$ <
o
CL
10
0
NITROGEN
CONTROL
ODOR
CONTROL
Figure 36.
5 10 20 30 40 50 60
MIXED LIQUOR TOTAL SOLIDS CONCENTRATION
mgx I0"3/l
Quantitative effect of treatment objectives on aeration requirements.
119
-------
A second method of establishing a nitrification-denitrification process
in an oxidation ditch consists of sizing the oxygenation capacity so
that conditions required for nitrification are achieved in a section of
the ditch directly in front of the rotor, while anoxic conditions exist
for some distance behind the rotor. Rotor aeration capacity must be
designed within close tolerance in order for the system to operate
effectively to remove nitrogen.
Cyclic rotor operation has been proposed in this model as the means of
removing nitrogen. Sufficient oxygen is supplied by the rotor during
the aeration period to achieve the required conditions for nitrification
throughout the channel, Denitrification occurs during that part of the
day when the rotor is not operating. This mode of operation for nitrogen
removal allows for system flexibility. The aeration cycle may be altered
to accommodate changes in treatment efficiency or waste loadings while
at the same time maintaining the treatment objectives.
The data obtained in the studies on sequential rotor operation are shown
in Figure 37. The maximum quantity of total nitrogen which could be
removed from poultry excreta was 90% of the input nitrogen. The maxi-
mum amount which could be conserved (no denitrification period) was 70%
of the input nitrogen.
On the basis of this data the following mass balance equation was used
to describe the total nitrogen concentration in the mixed liquor:
Se = So (<7 " kt^ for 0< t< 12
where S = mixed liquor total nitrogen concentration,
(mass/volume);
SQ = total nitrogen added to the ditch, (mass/day);
!<- = denitrification rate constant, (hour );
120
-------
CD
< Z
2 O
z :r
UJ u_
o
-------
t = length of the denltrification period,
(hours/day).
The coefficient 0.7 in the equation signifies the fraction of nitrogen
that can be conserved under no denitrifying conditions.
When using this process as a means of nitrogen removal, the aeration period
will be reduced depending on the extent desired. As a result, Equation (17)
must be modified to reflect the increased oxygen uptake rate. The following
equation is used in the model to express oxygen demand for a nitrification
system:
RN-D = n (fc"S + 4'57 fNSN^ " Oxy9en demand potentially available
from (NO, + NO,,) for denitrification
= n(f -S + 4.57 fNSN)- (3.7 N03-N + 2.3 N02-N)k-t (21)
where RN D = microbial oxygen demand for nitrification-denitrification
system of the type described (mass/time);
t = length of the denitrification period (hours/day).
If the treatment objective is nitrogen conservation rather than removal,
Equations 21 and 22 are applied in the model for conditions in which there
is not a denitrification period. As discussed earlier and demonstrated
in Equation 20, a maximum of 70% of the influent nitrogen was able to be
conserved in the preliminary experimental studies.
Rotor Size
In the cyclic rotor operation described above, as the aeration period, t,,
a
decreases in order to increase the extent of nitrogen loss due to denitrifi-
cation, the rate at which oxygen must be supported to the mixed liquor
increases. The length of rotor required appears to be proportional
122
-------
to the oxygen demand. The relationship between nitrogen removal and
the lengths of rotor needed to achieve these removals are shown in
Figure 38. Ninety percent removal of nitrogen as observed in our
studies correspond to 12 hours of rotor operation per day, and
30 percent removal corresponds to 24 hour operation of the rotor.
It must be noted that these are based on limited experience with the
different modes of operation of the oxidation ditch.
COSTS OF OPERATION IN FULL SCALE SYSTEMS
The feasibility of installing and operating waste stabilization
systems in oxidation ditches are largely dependent on costs.
Houghton Farm Operations
Some details of the capital and operating costs of the Houghton Farm
operation are given in Table 26. It can be noted that these cost
estimates do not include maintenance or interest charges. Certain
trade-offs in the total waste management system have not been considered.
Before the installation of the oxidation ditch system, it was necessary
to plow the soil following manure spreading to minimize the objection-
able odors. Such plowing is no longer necessary resulting in a dele-
tion of these costs. Costs associated with disposal have not been
included in the estimates. The estimates presented in Table 26 are
intended only to indicate that the economic impact of the installation
of the oxidation ditch system is reasonable.
Manorcrest Farms Operations
The operating costs are dependent upon the efficiency of the aeration sys-
tems. The cage and the brush type rotors require the use of 5 and 2 HP motors,
123
-------
4 r-
I
h-
O
Z
-------
Table 26. CAPITAL AND OPERATING COSTS FOR OXIDATION DITCHES
AT THE HOUGHTON POULTRY FARM
Cost Depreciation Cost per
($) (percent per year) dozen eggs
(0
Oxidation ditch $2800 10 0.093
(cost of construction)
Rotors 6116 10 0.204
Motors 1084 20 0.072
Power 1-010
(@ 2.17<£ per KWH)
Total cost per dozen eggs
based on estimated production of 1.379
300,000 dozen eggs per year
125
-------
respectively. Comparing the cost of the two systems shows' that with
proper design of aeration equipment, the operating costs may be reduced
(Table 27).
Mink Farm Oxidation Ditch System
From an economic standpoint, the operating cost of the JAM system, in terms
of energy consumption, is comparable to that of the cage rotor. The JAM
system has the flexibility of being able to be installed in phases to
meet the desired degree of stabilization. The total electric power need
for the JAM system for the 300 day period was 8010 kilowatt hours. Assuming
a value of 2£ per KWH, the operating cost was estimated to be 0.6<£ per
mink per day. The design considerations were based on oxygen requirements
only. The amount of oxygen transferred by the aerator was at least 7.5
times more oxygen than required on the basis of oxygen uptake by micro-
organisms in the wastewater. The power cost estimates of a better design
treatment system may be only ten percent of the present operating cost of
0.6<£ per mink per day.
LAND APPLICATION OF POULTRY WASTE
Land disposal will continue to be the main method for disposing of poultry
manure. Effective treatments have been developed, including the oxidation
ditch method, for minimizing odors. As a result of treatment, the kinds
and amounts of nitrogen compounds in the manure are altered. One of the
objectives of this study was to determine if treated manure could still
serve as a satisfactory source of N for plant uptake. An attempt was
also made to evaluate the effect of manures on the environment when
these manures were used as a source of N for plant growth.
126
-------
Table 27. OXYGEN REQUIREMENT, POWER AND COST DATA FOR THE
OXIDATION DITCH SYSTEMS AT MANORCREST FARMS, INC.,
CAMILLUS, NEW YORK
Parameter Cage Rotor Brush Rotor
Oxygen requirement (lb/hr/1000 birds)
Efficiency of equipment in tap water
(lb/ 02 per KWH)
Immersion depth (inches)
Rotor speed (RPM)
Power required (kilowatts)
Power supplied (KWH per hr)
Cost (i per bird per day)*
4
2.1
5
100
1.9
3.50
0.04
4
2.16
6
252
1.85
1.50
0.02
*Power cost is assumed to be 2i per KWH
127
-------
Oxidation ditch stabilized manure was found to be as effective as fresh
manure when used as a source of N for plant growth. Treatments such as the
oxidation ditch did not reduce the effectiveness of N for plant growth.
It was also determined that nitrogen from the two manure sources applied at
rates recommended for corn or grass production did not cause detrimental
levels of nitrates in surface runoff from soils. Differences in runoff
or soil loss could not be attributed to the source of manure.
It was noted in these investigations that soil nitrate levels under grass
were lower than those under corn. This indicates that actively growing
grasses are heavy feeders on nitrates in soil. On the other hand, nitrate
levels are highest in corn soils in June indicating that rapid mineraliza-
tion of N from manure is taking place but the corn plant, at the early
stage of growth, does not have the capacity for a large uptake of N.
These considerations must be taken into account when planning manure
management systems.
Residual effects from poultry manure are rather small in terms of corn
response when manure has been applied to supply up to 448 kg N/ha. Weather
conditions can affect this as they influence soil moisture and soil tempera-
ture. About 50 percent of the total N in manure was mineralized in the first
year as measured by corn and grass response. A much smaller percentage of
the remaining N is mineralized in subsequent years (20).
SUMMARY
In conclusion, it can be stated that the studies described in this report
indicate that it is possible to achieve the objectives of odor and nitrogen
control. Several approaches have been presented for nitrogen control in
128
-------
poultry wastes with the aid of an oxidation ditch. Either conservation
of nitrogen or its removal can be accomplished by operating the oxida-
tion ditch under appropriate and controlled conditions described in this
report. The results of this study indicated that up to 70% of the input
nitrogen to the oxidation ditch can be conserved and up to 90% of it
can be removed depending on the mode of operation chosen. Treated and
untreated poultry manure are good sources of N for plant growth. Corn
yields fertilized with about 200-400 kg N/ha compared favorably with
corn yields from commercial fertilizer N. Subsoil nitrate levels were
less than surface soil levels indicating most of the nitrates had not
moved below the 23 cm depth. Runoff losses of nitrates and phosphates
from manure were not affected by manure sources. The study also indi-
cated that other environmental objectives such as waste stabilization
and odor control need not be sacrificed when controlling nutrients.
129
-------
SECTION VII
DESIGN EXAMPLES
The following design procedure summarizes the discussion of the model
(28) for the design of an oxidation ditch continuous flow treatment
system for livestock wastes. It delineates those parameters which need
to be determined before the mathematical model can be used to establish
design and operating parameters and outlines the relevant parameters.
The first decision involves defining treatment objectives. In the
design procedure this is assumed to be a prior management decision.
DESIGN PROCEDURE
1) Determine raw waste characteristics on a per animal per day basis-
total solids, total COD, total Kjeldahl nitrogen, volume.
2) Determine treatability of the wastes, i.e., how much COD and how much
total nitrogen can be removed through extended aeration. Determine the
empirical solids removal rate from aeration studies.
3) Determine the number of animals above the ditch.
4) Calculate the ditch surface area required to collect the wastes from
these animals. Allow for a two to three foot median strip along the
center of the ditch.
130
-------
5) Using a design liquid depth approximately three to four times the
manufacturer's maximum recommended rotor immersion depth, calculate a
tentative design volume. This will then be the maximum allowable volume.
The rotor mixing requirements are directly proportional to the liquid
depth. The final liquid depth should, if possible, be one that will not
make design requirements for mixing higher than the rotor requirements
for oxygenation as specified by the treatment objective.
6) If possible, design the system to operate with a mixed liquor total
solids concentration of 20,000 mg/1 or less.
7) If the treatment objective is nitrogen removal, use Figure 38 to deter-
mine the design length of the denitrification period.
8) Determine oxygenation and pumping characteristics of the rotor'under
standard conditions. Rotor power consumption data will also be useful
to estimate operating costs.
9) The above data are then used to calculate the rotor design requirements
for mixing and oxygenation, the solids retention time, volume of make-up
water which must be added to maintain the constant volume and the mixed
liquor total nitrogen concentration. The computer program used is illustrated
in Appendix B.
10) Determine quantities of nitrogen which can be spread on available land
by multiplying
a) available bare ground area for spring or summer spreading x
224 kg/ha N
b) available grass meadow acreage for spring, summer or fall
spreading x 170 kg/ha N
131
-------
c) available grass meadow acreage to be plowed for corn the
following spring which can be spread in the previous spring,
summer or fall x 224 kg/ha N.
DESIGN EXAMPLE
An egg producer, located in close proximity to suburban housing, has a
poultry confinement unit with a total of 8,000 caged layers. He owns
sufficient land to grow his own feed and since nitrogen fertilizers are
in short supply, he would like to use the waste as a crop nutrient.
Since he is located near the suburban development, he is forced to con-
trol the foul odors which have been coming from the confinement unit.
On the basis of preliminary investigation of alternatives, the farmer
has decided to install an oxidation ditch since it will be the most
feasible means of achieving his objectives. He would like to know how
to design and operate the system.
The hens are housed in four long rows with stairstep cage arrangements.
There are 2000 hens in each row. In order to eliminate the need for a
separate collection and handling system, two oxidation ditches will be
built. Each ditch will collect the wastes from two rows of cages and a
three-foot wide median strip in each ditch is to be used as a walkway.
The treatment objectives are: a) odor control, and b) maximum nitrogen
conservation. Since the quantity of oxygen needed to conserve the nitro-
gen is larger than the quantity necessary to control odors, both treat-
ment objectives will be met if the system is designed for maximum nitrogen
conservation.
132
-------
A laboratory analysis of the raw waste indicates the following charac-
teristics:
Total Solids = 30,000 mg/bird-day
Total COD = 20,805 mg/bird-day
Total Kjeldahl nitrogen = 2,505 mg/bird-day
Volume = .ns liters/bird-day
In order for the wastes to fall directly into each ditch, a ditch length
of 152 feet and a channel width of six feet is needed. The design surface
area will be 2244 ft2.
The farmer has decided to purchase Thrive rotors to supply aeration and
mixing requirements in each ditch. The oxygenation and mixing capacities
of the rotor have been previously determined and are available. The manu-
facturer's maximum recommended rotor immersion depth is six inches. Since
mixing is hampered at liquid depths greater than three to four times the
immersion depth, the liquid depth cannot be greater than 24 inches. A
liquid depth of 20 inches is chosen. The ditch liquid volume will be
2740 ft3 (106,000 liters) as designed. In addition to the liquid depth,
the ditch should be constructed to provide a one foot freeboard clearance.
Since oxygen transfer efficiency of the rotor is greatest at a mixed liquor
total solids concentration at or near 20,000 mg/1, each ditch will be
designed to operate at a solids concentration of 20,000 mg/1.
Since the treatment objective is maximum nitrogen conservation, the system
will be designed for 24 hour rotor operation.
The value of f , f^t and KS, which describe the aerobic treatment of caged
layer poultry wastes have already been indicated and they may be used to
calculate rotor design parameters for this problem. Because of the
133
-------
inaccuracy in predicting K , the solids retention time, mixed liquor total
nitrogen concentration, and the rate at which make-up water must be added
will not reflect actual design conditions. The model predicted design
values of these variables are included in this problem for illustrative
purposes only.
The computer program is used to calculate the magnitudes of the remaining
design variables. The following is a list of the magnitudes of the control
and model predicted design data:
Number of hens over each ditch
Total channel length
Channel depth
Liquid depth
Liquid volume
Mixed liquor
total solids concentration
Rotor immersion
depth
Minimum length of rotor required
4,000
374 feet
2.7 feet (20 inches
+ 1 foot freeboard)
20 inches
106,000 liters
20,000 mg/1
6 inches
larger of rotor length required
for mixing and rotor length
required for oxygenation
6.8 feet
Solids retention times =
Mixed liquor total
nitrogen concentration
Make-up water to be added =
Rotor power consumption =
62 days
4,093 mg/1 as N
1,242 liters/day plus the amount
required to replace evaporation
losses
95 kwhr/day (for 6.8 ft of
rotor)
134
-------
REFERENCES
1. United States Department of Agriculture. Agricultural Statistics
1973. United States Government Printing Office, Washington, D.C
1973. 617 p.
2. Obers Projections: Economic Activity in the United States. Vol. 5.
United States Water Resources Council. Washington, D.C. Feb. 1972.
3. Effluent Guidelines Standards, Feedlots Point Source Category.
Federal Register. 39:5704-5708. February 1974.
4. Loehr, R.C., T.B.S. Prakasam, E.G. Srinath, and Y.D. Joo. Develop-
ment and Demonstration of Nutrient Removal from Animal Wastes.
Environmental Protection Technology Series, Washington, D.C.
EPA-R2-73-095. 1973. 340 p.
5. Prakasam, T.B.S., R.C. Loehr, P.Y. Yang, T.W. Scott, and T.W. Bateman.
Design Parameters for Animal Waste Treatment Systems. Office of
Research and Development, United States Environmental Protection Agency,
Washington, D.C. EPA 660/2-74-063, July 1974. 218 p.
6. American Public Health Association. Standard Methods for the Examina-
tion of Water and Wastewater. 13th ed. New York. 1971.
7. Jeris, J.S. A Rapid COD Test. Water and Wastes Engineering. 4:89-91,
1967.
8. Prakasam, T.B.S., E.G. Srinath, P.Y. Yang, and R.C. Loehr. Evaluation
of Methods of Analysis for the Determination of Physical, Chemical,
and Biochemical Parameters of Poultry Wastewater. (Presented at the
Pre-Winter ASAE Meeting, Chicago. December 11-15, 1971.) 72 p.
9. Montgomery, H.A.C. and J.F. Dymock. The Determination of Nitrite in
Water. Analyst 86:414-416, 1961.
135
-------
10. McKenzie, H.A. and H.S. Wallace. The Kjeldahl Determination of
Nitrogen: A Critical Study of Digestion Conditions, Temperature,
Catalyst, and Oxidizing Agent. Aust. J. Chem. (Sidney) 7:55-71,
1954.
11. Bremmer, J.N. Analysis of Total Nitrogen and Inorganic Forms of
Nitrogen. In: Methods of Soil Analysis. Madison, Wisconsin,
American Soc. of Agron., 1965. p. 1149-1232.
12. Greweling, T. and M. Peech. Chemical Soils Tests. Cornell Univ.
Agricultural Experiment Station, Ithaca, New York. Bulletin #960,
1965.
13. Fiske, C.H. and Y. Subbarow. Colorimetric Determination of Phos-
phorus. J. Biol. Chem. 66:375-400, 1925.
14. Menzel, D.W. and N. Corwin. The Measurement of Total Phosphorus
in Seawater Based on the Liberation of Organically Bound Fractions
by Persulfate Oxidation. Limnology and Oceanography. 10:280, 1965.
15. Methods for Chemical Analysis of Water and Wastes. U.S. Environmental
Protection Agency. Office of Technology Transfer, Washington, D.C.
EPA-625/6-74-003, 1974. 298 p.
16. Jacobs, M.B. and S. Hochheiser. Continuous Sampling and Ultramicro
Determination of Nitrogen Dioxide in Air. Anal. Chem. 30:426, 1958.
17. Methods of Analysis for the Association of Official Agricultural
Chemists. 6th Ed. A.O.A.C. Washington, D.C., 1945.
18. Wong-Chong, 6.M., A.C. Anthonisen, and R.C. Loehr. Comparison of
The Conventional Cage Rotor and Oet-Aero-Mix Systems in Oxidation
Ditch Operations. Water Research. 8:761-768, 1974.
19. Baker, D.R. Oxygen Transfer Relationships in a Poultry Mixed Liquor.
M.S. Thesis Submitted to Cornell University, Ithaca, New York.
August, 1973.
20. Bouldin, D.R. and D.J. Lathwell. Behavior of Soil Organic Nitrogen.
Cornell University. Ithaca, New York. Agricultural Experiment
Station Bulletin #1023. December 1968.
21. Loehr, R.C., D.F. Anderson, and A.C. Anthonisen. An Oxidation Ditch
for the Handling and Treatment of Poultry Wastes. In: Livestock
Waste Management and Pollution Abatement. ASAE. St. Joseph, Mich.
1971. p. 209-212.
136
-------
22. Stewart, T.A. and R. Mcllwain. Aerobic Storage of Poultry Manure.
In: Livestock Waste Management and Pollution Abatement ASAE
St. Joseph, Mich. 1971.
23. Dunn, G.G. and J.B. Robinson. Nitrogen Losses Through Denitrifica-
tion and Other Changes in Continuously Aerated Poultry Manure.
Proc. Cornell Agricultural Waste Management Conference, 1972. 178 p.
24. Edwards, J.B. and J.B. Robinson. Changes in Composition of Continuously
Aerated Poultry Manure with Special Reference to Nitrogen. Proc.
Cornell Agricultural Waste Management Conference, 1969. 178 p.
25. Scheltinga, H.M.J. Farm Wastes. Water Pollution Control. (London).
68:403, 1969.
26. Smith, R.J., I.E. Hazen, and J.R. Miner. Manure Management in a
700-Head Swine-Finishing Building: Two Approaches Using Renovated
Wastewater. Livestock Waste Management and Pollution Abatement.
ASAE. St. Joseph, Mich. p. 149-153, 1971.
27. Prakasam, T.B.S. and R.C. Loehr. Microbial Nitrification and
Denitrification in Concentrated Wastes. Water Research. 6:859-869,
1972.
28. Jones, P.H. and N.K. Patni. Nutrient Transformation in a Swine
Oxidation Ditch. JWPC . 46:366-379, 1974.
29. Kroeker, E.J. A Design and Management Model of the Oxidation
Ditch for Livestock Waste Treatment. M.S. Thesis Submitted to
Cornell University, Ithaca, New York. September 1974.
137
-------
SECTION IX
APPENDIX
138
-------
REAL PGWERU2), C2CAP(12)
4 FORMAT<5X,l4,9F10.i)
5 FORMATC* ','IMMERSION DEPTH TOO HIGH')
6 FORMAT(• «, 3F10.1)
READ, CS, PRESS
C INPUT RAW WASTE CHARACTERISTICS, CHANNEL CHARACTERISTICS,
C TREATABILITY DATA, AERATOR OXYGENATIQN AND POWER DATA
READ, WTS, TCOD, TKN? RWVOL, FN, FCCD
READ, AREA, WIDTH, N
READ, HENS, VOL, EFFTS, TIME
READ, (02CAPU), I=1,N)
READ, (POWER(I), 1=1,N)
DTS= EFFTS * VCL/10**6
CQD= TCCD * HENS/1C**6
TSIN= WTS*HENS
VSS = . 2 * DTS
C CALCULATION OF SOLIDS REMOVAL RATE CONSTANT
XK= .011 + .15*CCOD/VSS)
C CALCULATION OF MIXED LIQUOR SOLIDS RETENTION TIME
HRT= EFFTS*VOL/ (TSIN-XK*EFFTS*VOLJ
C VOLUME OF MIXED LIQUOR WASTED DAILY
FLOW= VOL/HPT
C VOLUME OF MAKE-UP WATER REQUIRED
WATER= FLOW-(RUVOL*HENS)
DEPTH= VOL * o03531/AREA
C DETERMINATION OF DESIGN PARAMETERS FOR MIXING, ODOUR
C CONTROL AND NITROGEN CONTROL AT EACH IMMERSION DEPTH
DO 50 I=1,N
IF (N/12 «GE. DEPTH) GO TO 40
CALL PUMPtOEPTH,VOL,AREA,I,XAREA,WIDTH,PCAP,Y,RFT1)
CALL 000R(TBOD,COD,HENS,DTS,ALPHA,BET A,CL,02CAP,CS,
1 PRESS, HP. BOO, RFT2, TRANS, EFFTS, I, FCODJ
CALL NIT(FN,TOD,TCOD,TKN,HENS,RATE,TIME,CL,CS,TRAN2,
102CAP,ALPHA,BETA,PRESS, RFT3,XKN,DEN IT,FTKN,EFFTS, I,
1FLOW,FCOD)
C CALCULATION OF ENERGY REQUIREMENTS FOR MIXING, ODOUR
C CONTROL AND NITROGEN CCNTROL
POW1= RFT1 * POWER(I) * TIME
POW2= RFT2 * PQWERU) * TIME
POW3= RFT3 * PCWER(I) * TIME
PRINT 4, I,RFT1,RFT2,RFT3,POW1,POW2,POW3,HRT,FTKN,
1WATER
PRINT 6, VOL, EFFTS, TIME
GO TO 50
40 PRINT 5
50 CONTINUE
STOP
END
139
-------
C SUBROUTINE FCP CALCULATING MIXING REQUIREMENTS
SUEPsOUTlNE PUMP
-------
IF (EFFTS etE. 55000.) GO TO 6
ALPHA= .4
GO TO 7
5 ALPHA= 1.
GO TO 7
6 ALPHA= -.17 * EFFTS/ 10**4 + 1.36
7 BETA= 1.
CL= 2.
C OXYGEN TRANSFER CAPACITY
TRAN2= 02CAP(I)*ALPHA*((BETA*CS-CL)/CS)*PRESS/14.7
C ROTOR LENGTH REQUIRED FOR NITROGEN CONTROL
RFT3= RATE/TRAN2
C MIXED LIQUOR TOTAL NITROGEN CONCENTRATION
XKN= .05
DENIT= 24. - TIME
FTKN= HENS*TKN*(«,7-XKN*DENIT)/FLOW
RETURN
END
141
-------
Nomenclature
ALPHA = ratio of K, a in the mixed liquor to K, a in water.
2
AREA = surface area of the channel, (ft ).
BETA = ratio of dissolved oxygen concentration at saturation for
wastewater to that of pure water.
CL = mixed liquor residual DO, (mg/1).
COD = total COD in mixed liquor, (kg).
CS = oxygen saturation concentration, (mg/1).
DENIT = length of the denitrification period, (hr/day).
DEPTH = liquid depth, (ft).
DTS = weight of total solids in mixed liquor, (kg).
EFFTS = mixed liquor total solids concentration, (mg/1).
FCOD = fraction of raw waste COD oxidized.
FLOW = rate of mixed liquor removal for disposal, (I/day).
FN = fraction of raw waste TKN which is biodegradable.
FTKN = mixed liquor total nitrogen concentration, (mg/1).
HENS = number of birds above the ditch.
HRBOD = average oxygen utilization rate, (gm Op/hr).
HRT = solids retention time, (days).
I = rotor immersion depth, (in).
N = maximum rotor immersion depth, (in.).
02CAP = oxygenation capacity of rotor in water, (gm 09/hr).
o <-
PCAP = rotor required pumping capacity, (ft /sec).
POWER = power consumption rate of rotor, (kw/ft of rotor).
POW1 = rotor power consumption for mixing, (kwhr/day).
POW2 = rotor power consumption for odor control, (kwhr/day).
POW3 = rotor power consumption for nitrogen control, (kwhr/day).
p
PRESS = atmospheric pressure, (Ib/in ).
RATE = microbial oxygen utilization rate, (gm 0?/hr).
142
-------
RFT1
RFT2
RFT3
RWVOL
TBOD
TCOD
TIME
TKN
TOD
TRANS
TRAN2
TSIN
VOL
VSS
WATER
WIDTH
WTS
XK
XKN
XREA
Y
= rotor length required for pumping, (ft).
= rotor length required for odor control, (ft).
= rotor length required for nitrogen control, (ft).
= volume of raw waste, (I/bird-day).
= microbial oxygen demand for odor control, (kg/day).
= total COD in raw waste, (mg/bird-day).
= daily length of aeration period, (hr/day).
= total Kjehldahl nitrogen in raw waste, (mg/bird-day).
= carbonaceous and nitrogenous microbial oxygen
demand, (gm 02/day).
= rotor oxygen transfer capacity, (gm Op/hr-ft of rotor),
= rotor oxygen transfer capacity, (gm Op/hr-ft of rotor),
= total solids added daily through raw waste, (mg/day).
= volume of the mixed liquor, (1).
= total weight of mixed liquor volatile suspended
solids in the ditch, (kg).
= rate of addition of makeup water, (I/day).
= width of the channel, (ft).
= total solids in raw waste, (mg/bird-day).
= solids removal rate constant, (day ).
= denitrification rate constant, (hr ).
p
= liquid cross-sectional area, (ft ).
*j
= rotor pumping capacity, (ftvsec-ft of rotor).
143
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1 PEPORT NO.
EPA-600/2-76-190
4 TITLE AND SUBTITLE
DESIGN PARAMETERS FOR ANIMAL WASTE TREATMENT SYSTEMS
NITROGEN CONTROL
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
September 1976 (Issuing Date
6. PERFORMING ORGANIZATION CODE
7.AUTH0R(s) R-C> Loehr, T.B.S. Prakasam, E.G. Srinath,
T.W. Scott, T.W. Bateman
8, PERFORMING ORGANIZATION REPORT NO,
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Department of Agricultural Engineering
Cornell University
Ithaca, New York 14853
10. PROGRAM ELEMENT NO.
1BB039
11. CONTRACT/GRANT NO.
S800767
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Athens, Georgia 30601
13 TYPE OF REPORT AND PERIOD COVERED
Final - Aug 1. 1971-Dec 31. 19
14. SPONSORING AGENCY CODE
EPA-ORD
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The objectives of this study were to: (a) develop design criteria for nitrogen and
odor control in animal waste stabilization systems; (b) demonstrate the feasibility
of nitrogen control using the oxidation ditch; (c) determine the rate, form, and time
of manure application permissible without causing surface or groundwater pollution; and
(d) determine the optimum rate, form, and time of application for best crop response.
Laboratory, pilot plant, and full scale studies were conducted to develop design
parameters for odor and nitrogen control. Information concerning the fate of
manurial nitrogen and crop response was derived from agronomic field studies.
A method of determining oxygen requirements for stabilization based on exerted carbona-
ceous and nitrogenous oxygen demand was developed. Controlled nitrogen removal in the
range of 30 to 90 percent was demonstrated. Nitrogen losses were due to ammonia vola-
tilization and/or nitrification-denitrification. Field studies indicated no difference
between raw and aerobically stabilized poultry manure in nutrient availability to plant
or surface runoff losses. At a given rate of manure application, soil nitrate levels
were higher under corn in comparison to grasses. The maximum recommended application
rate of poultry manure for corn was 224 kg N/ha. Application rates for grasses were
limited to 100-170 kg N/ha by plant response.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
cos AT I Field/Group
Runoff
Poultry
Waste treatment
Odor control
Nitrogen
Aeration
Corn
Liquid aeration systems
Nitrogen transformations
Land disposal
Animal waste treatment
Design parameters
Poultry manure
02/A/B/C/E
13. DISTRIBUTION STATEMENT
Release unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
158
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
144
* U-S. GOVERNMENT PRINTING OFFICE; 1976-657-695/6109
------- |