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

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                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.

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                                            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

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                              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

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                                  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

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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

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                                  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

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                                 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

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                         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

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                      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

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                           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

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                           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

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                                 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

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                            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

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                           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

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                              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

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                                 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

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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.

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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.

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                               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,

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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.

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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.

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                               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

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            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;

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(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

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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

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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

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(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

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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

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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

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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

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        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

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      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

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          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

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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

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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

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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

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                               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

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                                     TRIAL  I
                           I    1
                                   I	I
                                                      10
Figure 4.
                456789
                        DECEMBER  1973
Changes in the oxygen uptake rate during waste  stabilization.
                                33

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             0
 Figure 5a.  Changes  in  pH during stabilization and nitrification.
        2000r-
Figure 5b.   Changes  in concentration of nitrates during stabilization  and
            nitrification.
                                   34

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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

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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

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            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

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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

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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

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         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

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           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

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       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

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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

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    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

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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

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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

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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

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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

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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

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a*
                ZOOOi—
                 1500-
                1000 -
                 500 -
                                                                    50
180
210
                Figure 16.   Fluctuations  in nitrogen contents of mixed liquor in oxidation
                            ditch #1 at Manorcrest Farms.

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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.

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   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

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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.

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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

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            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

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                                 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

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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

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       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

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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

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               5           10           15          20         25
                               DAYS
Figure  35.  Aeration period and nitrogen losses in an oxidation ditch.
                              110

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         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

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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

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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

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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

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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

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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

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                       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

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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

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           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

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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

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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

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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

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      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

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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

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      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

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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

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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

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                               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.
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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

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    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

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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

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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

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                              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

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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

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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

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SECTION IX



 APPENDIX
    138

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      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

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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

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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

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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

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                                   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

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