United States
             Environmental Protection
             Agency
             Environmental Research
             Laboratory
             Corvallis OR 97330
EPA-600/3-79-003
January 1979
             Research and Development
SEPA
Performance of
Aerated Lagoons in
Northern  Climates

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                              REPORTING SERIES

Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series These nine broad cate-
gories were established to facilitate further development and application of en-
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      8    "Special" Reports
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This report has been assigned to the ECOLOGICAL RESEARCH series. This series
describes research on the effects of pollution on humans, plant and animal spe-
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This document is available to the public through the National Technical Informa-
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                                    EPA-600/3-79-003
                                    January 1979
          Performance of Aerated
       Lagoons  In Northern  Climates
            C. D. Christiansen
               H. J. Coutts
   Arctic Environmental Research  Station
   U. S. Environmental Protection Agency
          College, Alaska  99701
CORVALLIS ENVIRONMENTAL RESEARCH  LABORATORY
    OFFICE OF RESEARCH AND DEVELOPMENT
   U. S. ENVIRONMENTAL PROTECTION AGENCY
         CORVALLIS, OREGON  97330

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                         DISCLAIMER

This report has been reviewed by the Corvallis Environmental
Research Laboratory, U. 5. Environmental Protection Agency,
and approved for publication.  Mention of trade names or
commercial products does not constitute endorsement or
recommendation for use.

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                           FOREWORD

Effective regulatory  and enforcement  actions  by  the  Environ-
mental Protection Agency would  be virtually  impossible
without sound scientific data  on  pollutants  and  their impact
on environmental stability  and  human  health-   Responsibility
for building this data  base  has been  assigned to EPA's  Of-
fice of Research and  Development  and  its  15  major  field in-
stallations, one of which  is  the  Corvallis  Environmental
Research Laboratory (CERL).

The primary mission of  the  Corvallis  Laboratory  is research
on the effects  of environmental pollutants  on terrestrial,
freshwater, and marine  ecosystems;  the  behavior, effects and
control of  pollutants  in lake  systems;  and  the  development
of predictive models  on  the  movement  of pollutants in the
biosphere.  CERL's Arctic  Environmental Research Station
conducts research on  the effects  of  pollutants  on  Arctic and
sub-Arctic  freshwater,  marine  water  and terrestrial  system;
and develops and demonstrates  pollution control  technology
for cold-climate regions.

This report examines  the performance  of cold  climate aerated
lagoons and presents  the results  of  lagoon  studies conducted
by the Arctic Environmental  Research  Station.
                                      Jame s  McCarty
                                      Acting Director,  CERL
                             m

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                          ABSTRACT

Studies of cold climate aerated lagoons conducted by the
Arctic Environmental Research Station, Fairbanks, Alaska are
reported.  Conclusions are based on these studies, observa-
tions of full scale aerated lagoons operating in Alaska and
reports on lagoons in the northern tier of the United States
and Canada.

Biological processes which occur in facultative aerated
lagoons are reviewed and the performance of cold climate
aerated lagoons is examined.  Winter and summer performance
is compared, and general criteria for the design of cold
climate lagoons is presented.  Sample calculations for
predicting the performance of aerated lagoons are also
shown.  These calculations are based on the complete mix
equation for aerated lagoon design and on the results of the
data analysis presented in this report.  The information
presented indicates that lagoons can be designed or upgraded
to meet P. L. 92-500 secondary standards.  This may be done
by increasing the number of cells in series, by reducing
short circuiting and through the use of a polishing pond.
It is shown that additional cells in series, for a given
detention time, will increase the BOD removal efficiency of
a 1agoon .
                               IV

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                           CONTENTS

Foreword	-j-ji
Abstract	   iv
Figures	vii
Tables 	    x
Acknowledgment	xii

     1.  Introduction 	    1
     2.  Conclusions and  Recommendations	    2
     3.  Background	    5
              Lagoon Studies  in  Alaska	    5
              Facultative  Aerated  Lagoons 	    6
              BOD  Removal	    8
              Temperature  Effects	    8
              Mixing and  Short-Circuiting 	    9
              Sludge Accumulation	   11
              Algae	   12
              Coliforms	   14
              Aeration	16
              Oxygen Transfer 	   18
              Lagoon Design  	   24
     4.  Methods of Analysis  and
         Lagoon Description  i  Performance  Characteristics .   26
              General  Information	26
              Sampling  and Analysis  	   27
                    1)   Eielson  Air  Force  Base Experimental
                        Lagoon	28
                    2)   Ft. Greely  Lagoon	28
                    3)   Northway  Lagoon	30
              Eielson  Air  Force  Base  Experimental Aerated
              Lagoon	30
                    1)   Lagoon  Description 	   30
                    2)   Operation Problems 	   33
                    3)   BOD and  SS  Removals	34
                    4)   Algae  Growth	45
                    5)   Coliforms	47
                    6)   Nutrients	49
              Ft.  Greely  Lagoon	49
                    1)   Lagoon  Description	   49
                    2)   Aerator  Performance  	   51
                    3)   BOD and  SS  Removals	58
                    4)   Sludge  Accumulation  	   65
                    5)   Algae  Growth	68
                    6)   Nutrients	68

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              Northway  Lagoon	70
                    1)   Lagoon  Description	70
                    2.)   BOD  and  SS Removals	71
                    3)   Bottom  Sludge	74
                    4)   Nutrients	77
              Eagle  River  Lagoon	78
                    1)   Lagoon  Description	78
                    2)   Operation  Problems	79
                    3)   BOD  and  SS Removals	82
                    4)   Coliforms	86
              Eielson Air  Force  Base  Full Scale Lagoon.  •  •  89
                    1)   Lagoon  Description.  •	89
                    2)   Operation  Problems	89
                    3)   BOD  and  SS Removals	90
                    4)   Coliforms	93
              Palmer Aerated  Lagoon  and Polishing Pond ...  93
                    1)   Lagoon  Description	93
                    2)   Operation  Problems	95
                    3)   BOD  and  SS Removals	96
              Studies by  Others	99
     5.  Short-Circuiting  	 108
     6.  Ft. Greely  Oxygen  Transfer  Studies  	 114
              Methods and  Procedures	114
              Results	117
              Oxygen Budget 	 122
     7.  Discussion	125
              BOD and SS  Removal	.	125
              Soluble BOD  Removal	131
              Reaction  Rates	133
              Sludge Accumulation.	140
              Algae	144
              Nutrients	145
              Coliforms	146
              Aeration  Systems  	 149
              Aeration  Diffusers  	 151
     8.  Lagoon Design  and  Upgrading	155
              Discussion	155
              Sample Calculations	160

References	171
                               VI

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                      LIST OF  FIGURES


Number                                                       Page
  1   Eielson Air Force Base Experimental  Lagoon
  2   EAFB Experimental Lagoon  Performance  with  Fine  Bubble
      and Coarse Bubble Diffuser  Systems	42

  3   EAFB Experimental Lagoon  Performance  with  6  Cell  and  4
      Cell Operation	 43

  4   EAFB Experimental Lagoon  Winter  and  Summer  Percent  BOD
      Removal and SS Remaining  vs.  Detention  Time	44

  5   EAFB Experimental Lagoon  Chlorophyll  and  Suspended
      Solids vs. Detention  Time	46

  6   Plan View of Ft. Greely Coarse Bubble  Aerator  Instal-
      lation	52

  7   Chicago Pump Shearfuser Cluster  	 53

  8   Aer-0-Flo Non-clog  Diffuser  Cluster 	 54

  9   Ft. Greely Fine Bubble Diffuser  Performance  Data  .... 55

 10   Ft. Greely Coarse Bubble  Diffuser Performance  Data  ... 57

 11   Fine Bubble Diffuser  Summer  Aeration  Pattern	59

 12   Fine Bubble Diffuser  Winter  Aeration  Pattern	60

 13   Coarse Bubble  Diffuser Summer  Aeration  Pattern	 61

 14   Coarse Bubble  Diffuser Winter  Aeration  Pattern	62

 15   Ft. Greely Aerated  Lagoon  Sludge  and  Liquid  Tempera-
      ture,  1971 - 1972	•	67

 16   Ft. Greely Aerated  Lagoon  BOD, Chlorophyll  and
      Suspended Solids vs.  Summer  Sampling  Dates, 1972-  ... 69

 17   Eagle  River Aerated Lagoon  Sludge Blanket	81
                              vn

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18   Eagle River Aerated Lagoon Operating  Results	85

19   Eagle River Aerated Lagoon Effluent BOD  and  Suspended
     Solids Variability 	   87

20   EAFB Full Scale Lagoon Operating  Results 	   91

21   Palmer Lagoon Operating Results	98

22   Palmer Lagoon Effluent BOD and Suspended  Solids
     Variability	100

23   Visual Observation of Dye Injection in the  Ft.  Greely
     Lagoon...	110

24   Dye Injection Results, Ft. Greely  Coarse  Bubble
     Aerated Lagoon. .	Ill

25   Dye Injection Results, Ft. Greely  Fine Bubble  Aerated
     Lagoon	112

26   Air Flow Rate vs. K. a  .V for Aerated Lagoons 	  120

27   Year-round Percent BOD Removals vs. Detention  Time  • •  126

28   Year-round Percent Suspended Solids Remaining  vs.
     Detention Time	128

29   Winter Percent BOD Removal a'nd Percent Suspended
     Solids Remaining vs. Detention Time 	  129

30   Summer Percent BOD Removals and Percent  Suspended
     Solids Remaining  ..... 	 . 	  130

31   Soluble BOD vs. Detention Time .	132

32   Overall BOD  Removal   Rate Coefficient vs.  Loading.  . .  134

33   Overall Suspended Solids Removal  Rate Coefficient  vs.
     Loading	135

34   Winter BOD Removal Rate Coefficient vs.  Loading.  .  . .  136

35   Summer BOD Removal Rate Coefficient vs.  Loading.  .  . .  137

36   Winter Suspended Solids Removal Rate  Coefficient  vs.
     Loading..............	138

37   Summer Suspended Solids Removal Rate  Coefficient  vs.
     Loading.......	139
                             vm

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38   Aerated Lagoon Coliform  Removals	 147

39   Eagle River and EAFB Full  Scale Lagoons  Fecal  Coliform
     vs.  Chlorination Contact  Time	148

40   Suggested Lagoon Arrangement  	 .  	 158

41   Effect of Cells in Series  on  Detention  Time  	 169

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                              TABLES

Number                                                       Page

  1   Performance Summary of EAFB Experimental  Lagoon- ...   35

  2   EAFB Experimental Lagoon  Total  Coliform  Removal
      Results	   48

  3   EAFB Experimental Lagoon  Nutrient  Removal  Summary  .  .   50

  4   Performance Summary of Ft. Greely  Aerated  Lagoon.  .  .   63

  5   Ft. Greely Aerated Lagoon  Sludge  Analysis  	   66

  6   Ft. Greely Aerated Lagoon  Nutrient  Removal Summary.  .   70

  7   Performance Summary of Northway  Aerated  Lagoon ....   72

  8   Northway Aerated Lagoon Sludge  Analysis  	   75

  9   Northway Aerated Lagoon Nutrient  Removal  Summary.  .  .   78

 10   Eagle River Aerated Lagoon Performance  Summary ....   83

 11   Eagle River Aerated Lagoon Disinfection  Summary. ...   88

 12   Performance Summary of Eielson  Air  Force  Base Full
      Scale Lagoon	   92

 13   EAFB Full Scale Lagoon Disinfection Summary	   94

 14   Palmer Lagoon Performance  Summary	   97

 15   Performance Summary of Minnesota  Lagoons	102

 16   Performance Summary of Winnepeg  Lagoons  	  105

 17   Performance Summary of Harvey,  North Dakota Aerated
      Lagoon.....	106

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18   Harvey, North Dakota  Aerated  Lagoon  Fecal and Total
     Coliform Results	 107

19   Oxygen Transfer  Summary	118

20   Ft. Greely Coarse  Bubble  Lagoon  Oxygen Budget	 124

21   Sludge Accumulation  Summary  	 143
                              XI

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                       ACKNOWLEDGMENT
This report is a summary of work on aerated lagoons which
was initiated by Mr.  Sidney E.  Clark, first Waste Treatment
Research Director,  Arctic Environmental Research Sta-
tion (AERS).   His contribution  is gratefully acknowledged.

Much of the work covered in this report was accomplished
with the cooperation  of the U.  S. Air Eorce and U. S. Army.
Through an interagency agreement with the Alaskan Air Com-
mand, the AERS constructed and  operated, with Air Force as-
sistance, an  experimental facility at Eielson Air Force
Base, Alaska.  Much of the information contained in this
report was obtained from an aerated lagoon constructed as
part of the experimental facility.  Another interagency
agreement with the  U.  S. Army,  Alaska, allowed the AERS to
modify a full scale aerated lagoon at Ft. Greely, Alaska
which also resulted in a significant amount of the informa-
tion included in this  report.   Additional information was
obtained from a lagoon at Northway, Alaska through the
cooperation of the  Federal Aviation Administration.

The following individuals are  acknowledged as providing data
or information which  contributed significantly to the
completion of this  report:  Claude Vining and Ed Pohl of the
Corps of Engineers, Anchorage;  Jack Howard, Jim O'Niel and
the Waste Plant Operators, Eielson AFB; Mr. Mullens and Del
Ivester, Ft.  Greely;  Dick Hutson and Mike Pollen, Anchorage
Area Borough; William  Curtis and Jim Giyer, Palmer, Alaska.
                             XI1

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                          INTRODUCTION






Waste treatment lagoons have become increasingly popular in the




United States and Canada.  In spite of this fact, sufficient in-




formation has not been available to establish sound design




criteria, particularly for cold climate regions.  As was stated




in a recent state-of-the-art review (McKinney, et al. 1971),




"Only in a few instances has there been development of basic data




sufficient to produce sound criteria.  While there has been a




large number of studies in waste treatment lagoons, most of these




studies have been fragmented and lacking in sufficient depth to




have raal meaning.  If we are to continue to design and construct




waste treatment lagoons, it is important that we have proper




design criteria that will result in the production of the desired




effluent quality".






Aerated lagoons have many advantages which make them very




desirable for use in Alaska, especially since t-he standards for




lagoons have been revised.  The new standards allow for higher




effluent suspended solids during summer months to accommodate al-




gae growth.  Among the advantages of lagoons are low operating




and maintenance requirements, resistance to upsets and built-in




sludge digestion and storage capabilities.  A major disadvantage




is the large land area requirement.





                                1

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                  CONCLUSIONS & RECOMMENDATIONS






The performance of lagoons in northern climates has been




evaluated.  Methods for predicting the performance of aerated




lagoons in northern climates have been derived from pilot plant




and full scale operating data.  Conclusions can be drawn as fol




lows :






1.   Lagoon systems which can meet secondary standards can be




    designed for northern climates.  Raising the allowable sum-




    mertime effluent suspended solids should make the aerated




    lagoon a more attractive alternative.




2.   The following considerations should be kept in mind in




    designing or upgrading lagoon systems (see the section on




    lagoon design and upgrading):




    a.   Special attention should be given to the possibility of




        short-circuiting within the cells.  Strategic placement




        of baffles and aerators can reduce this problem.




    b.   Lagoon cells should be provided in series to red»ce




        short-circuiting due to complete mix conditions.  Cells




        in series also result in greater reductions in bacteria




        and algae for a given detention time.

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    c.   Heavy aeration should be provided at the lagoon influent




        in order to maintain influent solids in suspension.   This




        will increase the rate of conversion of dissolved and




        colloidal solids to suspended solids, which can be




        removed by sedimentation.  Also, the solids will undergo




        some aerobic decomposition and help prevent buildup of




        sludge under septic conditions which can retard




        digestion.




    d.   Adequate sludge storage  (1500 liters/1000 m  of domestic




        sewage) should be provided in the first sections of the




        lagoon so that aerobic oxidation of summer sludge diges-




        tion byproducts will occur in succeeding cells before the




        effluent is discharged.




    e.   A polishing or maturation pond should be provided as  the




        last cell in series.




    f .   The limited data on disinfection indicates that summer




        algae production results in disinfection rates similar to




        those during cold temperature operations in winter-






The performance of coarse bubble diffusers in aerated lagoons has




been evaluated.  The coarse bubble diffuser can provide an at-




tractive alternative to the fine bubble diffuser for aeration in




lagoons.  Conclusions may be reached as follows:






1.   Fine bubble diffusers are more efficient in oxygen transfer




    than coarse bubble diffusers, however, they are not neces-




    sarily more economical.

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2.  Power requirements in terms of Ib. 0_ transferred/hp-hr may



    be higher for fine bubble diffusers because of the restricted




    openings which require higher blower discharge pressures.




3.  Maintenance requirements for fine bubble diffusers are higher




    because of clogging which requires periodic cleaning.  The




    clogging also results in higher compressor maintenance due to




    increased discharged pressures.




4.  Oxygenation efficiencies published in the literature or sup-




    plied by coarse bubble diffuser manufacturers may be used for




    aerated lagoon design.




5.  In areas where ice fog is a problem,  a larger number of dif-




    fusers (less air flow per diffuser) at an increased spacing




    would minimize the generation of ice  fog without sig-




    nificantly affecting oxygenation efficiencies.






6.  Excluding transfer efficiency,  a ratio of 1.5 g 0?/g BOD,.




    removed  was found  adequate  for  sizing aeration  equipment for



    cold  climate aerated lagoons.

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                           BACKGROUND









LAGOON STUDIES IN ALASKA






Pohl (1967) presented a theoretical discussion of cold climate




aerated lagoons.  Clark et al., (1970) provided an extensive sum-




mary of lagoon operations under cold climate conditions and




Grainge et al . ,  (1972) reviewed Canadian experiences with




lagoons.  Design criteria for arctic and subarctic aerated




lagoons has been presented by Reid (1970, 1975).









One of the first aerated lagoons in Alaska was an experimental




facility located at the Eielson Air Force Base near Fairbanks and




operated by the  Arctic Health Research Center of the U.S. Public




Health Services  in 1964 and 1965 (Reid, 1970).  This lagoon




established the  feasibility of utilizing aerated lagoons in the




subarctic.  Late in 1967, the Alaskan Air Command and the Arctic




Environmental Research Station entered into an agreement to con-




struct and operate a field research facility that included an




aerated lagoon pilot plant at Eielson Air Force Base.  Also,




during this period, Pohl (1967) presented an approach for the




design of aerated lagoons.  Based on the information established




from these initial efforts and the Alaska State Water Quality

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Standards in effect at that time, a number of aerated lagoons




were constructed in Alaska, particularly for remote government




installations.  These lagoons have been successful  for  the most




part but have not been without problems and were generally unable




to meet the 30/30 secondary standards required by  Public  Law




92-500.








The secondary standards for lagoons have been revised to  allow




for higher effluent suspended solids (SS) levels during summer




months  (Federal Register, 1977).  The Alaska Operations Office




of  the  Environmental Protection Agency has submitted a  value of




70 mg/1 as the SS limit for summer operation (Dan  Crevenston,




Personal Communication 1977).  The effluent must also appear




green for this high value to apply.  The standards  for  BOD ef-




fluent  levels remain the same.  The 70 mg/1 value  is base on ac-




tual lagoon operating data and applies to the state of  Alaska




only, since each state is required to determine a  value in-




dividually.  This approach will allow lagoons to be designed




based on BOD requirements but eliminates the need  for special




equipment or operations for algae removal.









FACULTATIVE AERATED LAGOONS






The incomplete mix or facultative aerated lagoon is designed with




sufficient aeration capacity to ensure uniform oxygen concentra-




tion throughout the liquid but insufficient capacity to maintain

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solids in suspension.  As raw waste enters the  lagoon,  the




settleable solids are deposited while the soluble  and colloidal




organic matter undergo assimilation and oxidation.   As  the




suspended solids (SS) undergo oxidation, a portion  of these  are




deposited also .









The settled sludge undergoes anaerobic decompostion .  The degree




of decomposition is directly related  to temperature.  The




byproducts of anaerobic decomposition are diffused  into  the




aerobic liquid to undergo further oxidation.   In  the presence  of




sunlight, algal growth also occurs, converting  carbon dioxide  in-




to organic compounds and oxygen.









Four principal biological transformations which occur in  all




types of  lagoons are described by Oswald (1968).   These  are:




(1) aerobic oxidation which produces  bacterial  sludge,  carbon




dioxide and water; (2) anaerobic decomposition  which produces  or-




ganic acids and related compounds;  (3) organic  acid  decomposition




which forms methane and carbon dioxide; (4)  algal  growth  which




converts  carbon dioxide into organic  compounds  .and  free  oxygen.




Knowledge of these reactions is essential for  an  understanding




of the facultative aerated lagoon.

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BOD REMOVAL





Eckenfelder (1970) has presented the relationship which is used



for lagoons approaching a completely mixed regime.  Based on a



material balance, the following first order reaction equation can



be developed:




          Se/So = l/(l+Kt)



          where    K = k X
                    S  = Influent BOD
                     o


                    5  = Soluble effluent BOD
                     e


                    X  = Basin volatile suspended solids



                    t = Detention time, days



                    K & k = Removal rate coefficient.
Because of the present inability to define the rate of solids



settling, etc., in an incomplete mix lagoon, the overall reaction



rate coefficient K is generally used.






TEMPERATURE EFFECTS





The effect of temperature on biological process reaction rates



can be predicted by the following relationship:

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               K206
                   (T-20.)
          K
           T
         K
          20
           T
= Desired reaction rate at temperature T
= Known reaction rate 20°C
= Temperature
= Temperature coefficient
Values of 0 vary widely depending on the type of process con-
sidered .

Eckenfelder and England (1970) summarized temperature effects as
follows:
      Process
      Stabilization Pond
      Activated Sludge
      Aerated Lagoon
      Tr ickling Filter
      Aerobic Facultative Lagoon
      Anaerobic Lagoon
      Extended Aeration

MIXING AND SHORT-CIRCUITING

Flow through lagoons have been described as either plug or com-
plete mix as characterized by the following equations:
                          Range of 6^
                        1.072 - 1.085
                        1.0   - 1.041
                        1.026 - 1.058
                        1.035
                        1.06  - 1.18
                        1.08  - 1.10
                        1.037
Temperature
 Range °rj
    3-35
    4-45
    2-30
   10-35
    4-30
    5-30
   10-30

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                   Plug Flow     S /S  = e~kt
                      3           e  o


                   Complete Mix  S /S  = l/(l+Kt)
                                  G  O




Thirumurthi (1969), indicated that neither condition exists  in



sanitary engineering practice and that actual conditions  are



somewhere in between.  He presented an equation for organic



removal which included a dispersion coefficient which  would  ac-



count for short-circuiting and mixing characteristics, exit  and



entrance conditions, etc.  Murphy and Wilson (1974) have  also



reported that lagoon mixing patterns differ significantly  from



either complete mixing or plug flow conditions and used a  disper



sion coefficient in describing organic removals.  These methods



require extensive knowledge of lagoon characteristics.  Murphy



and Wilson suggested that the following equation be used  for



rapid analysis of aeration basins in series.



                        n

                S /S  = n(l/(l+Kt.))
                 G  Q            1
                          t. = Residence time for each



                               respective cell.
The provision of a number of aeration cells in series will  im-



prove lagoon performance by reducing the opportunity for short-



circuiting and by providing conditions more closely related to



plug flow.  Gloyna and Aguirre (1970) reported greater suspended
                                10

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solids and bacterial reductions in facultative ponds operated  in




series compared to single cell units.  Reid (1975) has suggested




that providing more than four cells in series will not improve




performance significantly.






Some mixing is required to provide adequate dissolved oxygen




levels throughout the lagoon.  In general, this is accomplished




when sufficient aeration is supplied for biological oxidation.




Mixing also prevents thermal stratification and allows the bottom




sludge to warm up during the summer months which should increase




anaerobic activity.






SLUDGE ACCUMULATION






Because of the low mixing levels which occur in long detention




time lagoons, deposition of biological sludge occurs.  Clark




et al . (1970), summarized cold climate facultative pond installa-




tions and reported accumulations of 250-400 liters per




1000 people per day (8.8 - 14.0 cu. ft./1000 people-day).






Middlebrooks et al. (1965), in an investigation of sludge ac-




cumulation in lagoons, determined that where the percentage of




total solids is high the volatile portion is generally low.   This




condition would indicate that a large portion of the sludge must




be silt and other inorganic matter washed into the lagoon.  The




time required for thorough digestion in sludge lagoons is




estimated at 3 years (Vesilind, 1975).  For streams in temperate
                                11

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climates, Fair has estimated the rate at which sludge deposits




stabilize as follows (Mueller and Su, 1972):






                    50%                  0.3 years




                    90%                  1.5 years




                    99%                  5.4years






These values indicate that it takes  at least 5 years  for  an




aerated lagoon to reach equilibrium  and to complete the aging




process.






ALGAE






Algae exist in lagoons in a symbiotic relationship with bacteria




and require H?0, inorganic nutrients and carbon dioxide for




growth.  Typical green algae found in lagoons are Chlorella,




Chlamydomonas and Euglena with the latter two tending to  dominate




in cooler weather (Gloyna, 1968).






Studies have shown that massive algal blooms are associated  with




excessive amounts of decomposable organic matter and  that  C0?  is




the major nutrient required for growth (Kuentzal, 1969),  (Foree




and Wade, 1972).  Kuentzal (1969) reported that bacterial  action




on large amounts of organic matter can supply as much as  20  mg/1




of C0_ in a super saturated state and result in large algal  bloom




development.
                                12

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Waste stabilization ponds which receive optimum  amounts  of  waste




for growth conditions discharge planktonic algae whereas, in




ponds receiving relatively small loads, the algae  settle  out




and/or are consumed by planktonic phagotrophs such as  Daphnia  or




Cyclops (Gloyna, 1968).  Dinges (1975) has described the  environ-




ment desirable for cultivating zooplankton, which  he indicated




can filter and consume bacteria, colloids and algae in stabiliza-




tion ponds.  He suggested the following:




     (1)  pH should be maintained between 7.0 and  8.0.




          Ammonia dissociates at high pH levels  and




          becomes toxic to a variety of zooplankton.




          High pH results from excessive algae growth.




          Algae can be controlled by reducing organic




          carbon which is converted to carbon dioxide




          by bacterial respiration.




     (2)  Dissolved oxygen should be 1 mg/1 or greater




          as the zooplankton will not survive under




          anaerobic conditions.




     (3)  Gentle mixing should be present to prevent




          pockets of  stagnation and preclude soluble




          sulphide evolution.  Wind action can




          generally provide sufficient mixing.




     (4)  Rubble will increase the productive poten-




          tial by providing living space.
                                13

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COLIFORMS






A reduction in coliforms of  several  orders  of  magnitude  occurs




in aerated lagoon and oxidation  pond  treatment systems.   Disin-




fection may be necessary, however,  in  order to meet  state water




quality standards.   The disinfection  step  in aerated lagoon




design apparently receives little attention other  than  to provide




a contact chamber of a certain nominal  retention  time  and a means




of feeding chlorine  to the effluent  stream.






Two  aspects of disinfection  of aerated  lagoons in  the  sub-arctic




must  be considered:  the algae blooms  which occur  during  the  warm




summer months of long daylight hours,  and  the  long period of  near




0°C  effluent temperatures during winter months, which  increases




pathogen survival rates and  affects  disinfection  requirements.




Both  situations require special  attention  in the  design  of lagoon




treatment systems.






Slanetz et al . (1970) found  die  off  rates  of 95-99?o  in  wastewater




oxidation systems utilizing  one  pond  or two  ponds  in series at




17-26°C.  The ponds  were 5 to 10 acres  in  size.   Much  better  sur-




vival rates were found in the winter  at pond temperatures of




1-10°C.  Salmonellae and viruses were  isolated in  the  majority




of effluent samples.  Systems having  3  or  4 ponds  in series




resulted in very few indicator bacteria remaining  in the  ef-




fluent.  The  numbers of bacteria were  again much  higher in  the




winter and  enteric pathogen  isolations more  frequent.  Gordon







                               14

-------
(1972) has shown the survival rates of  indicator  bacteria  are




much greater in subarctic streams under  winter  conditions.






Mixing is very important for efficient  chlorine disinfection.




White (1972) has shown that high suspended  solids  levels have




little effect on chlorine requirements  when  adequate  premixing




is provided.






The chlorination of treated wastewater  effluents  at  0-10°C  have




been investigated  in a model contact chamber  at the  AERS (Gordon




et al . 1973).  The results of the study  indicated  that  effective




chlorination can be accomplished at temperatures  less  than  1°C




provided an actual contact time of no less  than one  hour is




provided and adequate premixing of the  chlorine is practiced.




These conditions seldom occur in practice.   The authors reported




a nominal detention time of 2 hours was  necessary  in  the well




baffled contact chamber model to provide  a  one-hour  actual  con-




tact time .






A number of studies indicate that successful  chlorination  of al-




gae laden oxidation pond effluents can  be attained;  however, the




BOD of treated wastewater effluent containing algae  can be  in-




creased by excessive chlorination (White, 1972).   Horn  (1970) sug-




gested that two reactions appear to occur:   first, the  algae




suffer surface damage and, second, the  cellular contents are




released which increases the BOD.  Bacteria  can be destroyed and




the algae left essentially intact by controlling  time  of reaction






                                15

-------
and concentration of chlorine.  The following optimal conditions




were reported :





                                        Chlorine (mg/1)




       Contact Time (Min)         Applied         Residual






               15                   5.0             2.4






               60                   3.4             1.0






Kott reported work on 5 simulated pond effluents using raw  and




secondary treated domestic sewage in which no algae kill  occurred




with up to 2 hours detention time and 8-14 mg/1 chlorine  dosages




(White, 1972).  Indicator bacteria were reduced from 10   and




107/100 ml down to less than 20/100ml after 30 min. at 30°C.




White  (1972) recommended the chlorination chamber for wastewater




ponds be designed for one hour contact time at average flow but




not longer than two hours.  The velocity should be 2 ft/min.  to




prevent deposition of dead algae and adequate provisions  for




cleaning should be made.  The chlorination equipment should




provide for 15 mg/1 dosage at maximum flow.






AERATION








Oxygen requirements based on biological sludge synthesis  and




respiration and the bottom sludge demand have been discussed  by




Pohl (1970).  The relationship for the synthesis of new cellular




material is expressed as follows (Eckenfelder and O'Connor,




1961) :



                               16

-------
      S = al_  - bS
            r     a




          where  S = net accumulation of Volatile



                     suspended solids



                 a = fraction of 5 day BOD removed which is



                     synthesized to new biological sludge



                L  = Ib/day BOD removed



                b  = rate of endogenous respiration,



                     fraction per day



                S  = Ib of mixed liquor volatile
                 3


                     suspended solids.





The oxygen required per day for synthesis and respiration is



determined by the following equation  (EckenfeIder, 1970)





          Ib 00/day = a' S  + b1 MLVSS
              2           r


                      a' = 1-a based  on ultimate  BOD



                      b' = 1.4b





For the 5 day BOD, the following conversion must  be used





                      a1 = BODu/BOD5  - 1.42a





In aerated lagoons in which solids deposition is  allowed to occur



and BOD is fed back to the liquid from anaerobic  fermentation,



the following relationship can be used:





          Ib of 0 /day = a11  Ib BOD   removed/day
                                17

-------
Values of a11  should be 1.2 to 1.4.  In other words, the oxygen



requirement for oxidation of digestion products is increased by



20 to 40?o.  Endogenous respiration is ignored because of the low



suspended solids level in the basin.





The aeration system requirements for  aerated lagoons have been



reviewed elsewhere (Christiansen and  Smith, 1973).  Surface



aerators are not recommended for cold climate operations because



of icing problems which occur (Penman, 1970), (Clark et al.,



1970) .





OXYGEN TRANSFER





The general transfer equation for oxygen in wastewater is as fol



lows :
     dc/dt = 0K, a(BC -C)  - r
               L    S
              dc/dt = Change in concentration (mg/l-hr)



                K. a = Overall transfer coefficient (hr~ )



                  a = Ratio of K. a in a wastewater to K. a



                      of tapwater



                 Cg = Oxygen saturation concentration (mg/1)



                  C = Oxygen concentration in liquid (mg/1)



                  3 = Ratio of C  in wastewater to C
                                s                   s


                      in tapwater



                  r = Oxygen Demand Rate (mg/l-hr)
                               18

-------
The overall oxygen  transfer  coefficient  K. a,  can  be  used for

determining the performance  of  aerators.   Examination  of the

above equation shows  that  when  a  biological  system  is  operating

under steady state  conditions,  the  rate  of oxygen transfer will

equal the oxygen  demand  rate.   Therefore,  by  determination of the

oxygen demand rate, a , g ,  and  oxygen  in  the  liquid,  K. a can be

calculated  (Benjes,  1969),  (Conway  and  Tumke ,  1966),  (Ecken-

felder,  1959).


Several  attempts  have  been  made  to  predict the  value  of K. a in

diffused  air systems.   Eckenfelder,  1959  has  shown  that for a

given aerator, K. a  is  influenced  by  air  flow  rate,  depth of dif-

fuser submergence  and  the  tank  and  aerator configuration.   Smith

(l970) has  shown that diffused air  systems  can  be scaled up

geometrically.   The following  equation  was developed  by Ecken-

felder :

            C Gs(1-n)H2/3
     K - 3  —
                  v

          C = Constant

          G  = Air  flow  rate  per  diffuser
          o

          H = Liquid  depth

          V = Basin volume  per  diffuser

      (1-n) = Gas  rate  exponent  characteristic  of

              diffuser  type
                                19

-------
The exponent of 2/3 for H has been  found  to vary  for  commercial
aeration tanks with the values of 0.88  for sparjers and  0.72  for
saran tubes reported (Eckenfelder and Ford, 1968).

Eckenfelder 1961 has indicated surface  transfer  in  lagoons  will
be 10 - 20 percent of the total.  Since the transfer  rate  is  in-
dependent of diffuser spacing provided  the spacing  is  sufficient
to minimize interfering bubble patterns (Eckenfelder,  1968),  dif-
fuser placement is not expected to  be a factor in larger  aeration
basins .


The difference between the oxygen saturation concentration  and
the concentration in the liquid is  the  driving force  for  the
transfer process.  The average saturation value  (C  )  at  tank  mid-
                                                  s
depth is used and may be determined as  follows (Eckenfelder and
O'Connor, 1961).

     Cs = Cw(Pb/29 + Ot/42)
          where C  = Oxygen saturation  concentration  at
                     barometric pressure
                P.  = Psia at aerator depth
                0,  = Percent oxygen by  volume in  air
                     leaving tank

Regarding the  effects of wastewater on  C  , the effect  is  rela-
                                        S
tively minor when the dissolved solids  in an aeration  basin are
less  than 0.2  percent.   Values of 0.95  have been  found for B
where  dissolved solids were in this range (Pfeffer, 1969).
                               20

-------
The effect of wastewater on K.a  is  considerable  more  difficult




to evaluate and extreme care must be  used  in  its application.




Eckenfelder and O'Conner (1961)  and  Eckenfelder  and  Ford  (1968)




list a values for various wastes and  aerators.   They  indicate,




however, that evaluation of a  requires  measurement  of the  respec-




tive K.a values under mixing intensities  and  surfactant  levels




found in practice.






The K, a value is also influenced by  temperature  which may  be  ac-




counted for through  the Arrhenius temperature  correction  equation




related to 20°C as follows:






     KLa(T) = KLa(20)e(T~20)




                0 =  Temperature  Coefficient




                T =  Temperature, °C






Pfeffer (1969) stated that reported  values  of  0  range from 1.016




to 1.047 and that 1.024 is frequently used.   He  suggested  that




in most practical systems the  value  will  be  between  1.02  and




1.03-  Eckenfelder and Ford (1968)  indicated  an  evaluation showed




0  to be 1.02 for K. a in a bubble aeration  system.   Hunter  and




Ward (1972) found that K.a varies linearly  with'  temperature.




However, their data  show a relatively small  difference between




the use of 1.024 for 0 in the  Arrhenius equation and  the  linear




model between 0°C and 25°C.
                                21

-------
The following  > 3 a brief description of some  submerged  aeration




device, '-j which have been utilized in aerated lagoons:






     1,  Perforated tubing diffusers (Air Aqua  Systems)  supplied




by Hinde Engineering Company, Highland Park,  Illinois,  consists




of flexible plastic tubing with perforations  cut  on  the  top  and




a lead keel on the bottom to keep it submerged.   This  type  of




aeration was originally used for the upgrading  of  stabilization




lagoons.






     2.  Porous ceramic diffusers supplied by Hydro  Ceramic  Com-




pany, Anchorage, Alaska (Pohl, 1970).  Consists of PVC  tubing




with porous ceramic stones inserted one foot  apart.  Each  stone




provides about 3.2 sq cm of surface area.  The  tubing  is sup-




ported off the lagoon bottom by pylons.






     3.  Air Gun aerators supplied by Aero-Hydraulics  Corp., Mon-




treal (Dutton and Fisher, 1966), (Penman, et  al.,  1970).   These




consist of submerged vertical plastic pipe normally  30  cm  in




diameter and of varying lengths with an air chamber  at  the  lower




end.  Air is pumped into the chamber and builds up until released




by a siphoning effect through the pipe.  The  rising  air  bubble




"piston" draws in water from holes in the pipe  located  j»ust  above




the  air chamber and a pumping action occurs.  Air  Gun  aerators




are  designed for use in deeper lagoons and promote mixing  as well




as oxygenation.
                               22

-------
     4.   The INKA aeration system designed by Industrikemeska  Ak-




tiebologet of Stockholm, Sweden, was studied in a pilot lagoon




at Laramie, Wyoming (Champlin, 1971).  The INKA aeration system




is designed for low pressure operation and in this case consisted




of three grids of 1 m X 2.5 m with 5 mm orifices located on the




bottom of the grid.  The grids were placed at a depth of 0.8 m




below the surface and circulation in the lagoon was controlled




by baffling.




     5.   Aer-0-Flo non-clog diffussrs supplied by Aer-0-Flo Cor-




poration, Florence, Kentucky.  Consists of a cap which rests on




a 3 mm pipe orifice.  When air is flowing, differential pressure




raises the cap about 1.6 mm.  Air flows radially under the cap,




theoretically rising through small holes in the cap.  When air




is shut  off, the cap falls back against the orifice and prevents




solids from backing up  in the system, simulating a check valve.






     6.   Chicago Pump Shearfusers supplied by Chicago Pump Co.,




FMC Corp., Chicago, Illinois.  Consists of a bo* 19 cm square




with a one-inch air injection orifice entering the side near the




bottom.   As air rises in the box, water is pulled in and the




resulting shearing action causes the air to break up into smaller




bubble s.






     7.   Kenics Aerator supplied by Kenics Corporation, Danvers,




Massachusetts.  The aerator is a motionless mixer consisting of




a polyethylene tube and alternating right and left hand helices.




The units act as air lift devices.





                                23

-------
LAGOON DESIGN






That lagoons c aTi be designed and operated to meet the standards




has been demonstrated.  Oswald et al.  (1970) described a lagoon




system at Saint Helena, California, which achieved excellent  ef-




fluent characteristics including an average BOD level of




3.9 mg/1.  The lagoon system consisted of facultative, aeration,




algae sedimentation and two maturation ponds, all in series and




totaling 110 days detention time.  Other methods of meeting stan-




dards without the need for polishing filters, etc., have also




been described.  Pierce (1974) reported on 49 lagoons in Michigan




practicing long term storage prior to  effluent release.  He in-




dicated that lagoons can produce effluents meeting EPA require-




ments for BOD and fecal coliforms and  generally can meet the




suspended solids requirements by practicing long term storage  and




discharging in the spring and fall.  Hiatt (1975) reported on  a




pilot program of phase isolation in which lagoon effluents were




transferred to a pond and held for 2 weeks before discharge.   Ex-




cellent results were obtained with extreme reductions in the  al-




gae populations, apparently due to the change in conditions ex-




perienced by the algae after transfer  to the holding pond.






Oswald et al. (1970) has suggested that optimum removals cannot




be obtained from any one type of lagoon because of the many dif-




ferent biological processes which occur.  Optimum conditions  for




one process will not necessarily be optimum for another.  He  has
                                24

-------
suggested that different types of lagoons operating in series are




necessary for an optimum lagoon system.
                                25

-------
                     METHODS OF ANALYSIS AND




        LAGOON DESCRIPTION & PERFORMANCE CHARACTERISTICS






GENERAL INFORMATION






Following is a brief summary of some subarctic aerated lagoon




performance information which supports the conclusions presented




in this report.  Information included in this section has been




obtained from experimental and full scale aerated lagoons located




at Eielson Air Force Base (EAFB), Northway, Ft. Greely, Eagle




River and Palmer.  The EAFB experimental lagoon was part of  an




experimental facility constructed jointly by the Alaskan Air Com-




mand and the Arctic Environmental Research Station.






The EAFB, Northway and Ft. Greely lagoons are discussed primarily




in reference to effectiveness of multiple cells, short-




circuiting, sludge accumulation, and algae production.  The  Eagle




River and Palmer lagoons were included to allow comparison of two




full scale lagoons of different design, operating under similar




conditions.






The climate at EAFB, Northway, and Ft. Greely is very similar to




that of Fairbanks, which is located at 64 1/2 °N latitude.   The




mean annual temperature at Fairbanks is approximately - 4 ° C .  The
                                26

-------
sunshine varies from a winter low of approximately  3  3/4  hours




to a summer maximum greater than 22 hours.   The  Palmer  and  Eagle




River lagoons are located near Anchorage where  the  mean annual




temperature is about 2°C and the hours of sunshine  vary from




5 1/2 hours in the winter to 19 1/4 as a summer  maximum.






Biochemical oxygen demand (BOD), chemical oxygen  demand (COD)  and




suspended solids  (S3) data  (if available) are summarized  for  each




of the lagoons discussed.   Winter and summer operation  refers  to




periods when the  lagoon effluent temperature was  less  than  1°C




and greater than  10 ° C respectively.






"Fine bubble diffusers", as used hereafter,  refer  to  restricted




diffusers such as the perforated tubing  and  porous  ceramic  types.




"Coarse bubble diffusers" refer to larger orifice  types such  as




the Aer-0-Flo or  Shearfuser diffusers.






SAMPLING AND ANALYSIS






All analyses for  the Eielson experimental Ft. Greely  and  Northway




lagoons were performed at the Arctic Environmental  Research




Laboratory in accordance with Standard Methods,  (1965,  1971).




Samples for the Eagle River and Eielson  full scale  lagoon  were




collected by the  Greater Anchorage Borough  Public  Works Depart-




ment and Eielson  AFB personnel respectively  and  analyzed  in  ac-




cordance with standard methods.  The Palmer  lagoon  samples  were




collected by city employees and analyzed with Hach  field  eguip-




ment .





                                27

-------
Eielson Air Force Base Experimental Lagoon






Eielson plant lagoon feed samples were 24-hour composites  col-




lected with a surveyor sampler supplied by  N-Con  Systems  Company,




Inc.  Cell samples were grab and were collected by  means  of  a




pump through insulated and heat-taped tubing  which  entered each




cell at mid-depth and extended approximately  1 foot into  the  li-




quid.  Samples were generally collected once  per  week  and




analyzed for pH, BOD (5-day, 20°C), COD, solids and coliform  in-




dicators.  Nutrient samples were collected  once per month.   Each




sample line was flushed before collection.  The samples were  im-




mediately placed in an ice chest and returned to  the laboratory




within 2 to 3 hours for analysis the same day.  COD and nutrient




samples were occasionally preserved by freezing for later




analysis.






Problems were encountered during the last few months with




plugging of the cell 5 sampling tube.  As a result,  some  samples




were missed and those that were collected appeared  to  give low




results.  These were not included in the data analyses.






Fort Greely Lagoon






Nearly all of the Ft. Greely influent samples were  collected




using a composite sampler.  An N-Con Systems  Company trebler




oscillating scoop proportional sampler was  originally  utilized




in the Palmer Bowlus flume before the lift  station  but was aban-
                              28

-------
doned because of fouling by large solids particles.   A  home-made




sampler was then constructed which consisted of a container  with




an inlet tube which was placed in the splitter manhole.   Each




time the lift pumps operated, liquid would rise above the  inlet




tube and run in the collection container during the  short  period




the pumps were in operation.  This proved to be an improvement




because the solids were largely pulverized by the lift  pumps




before reaching the splitter manhole.






All effluent samples were grab.  Each sampling operation  required




at least two days.  The general procedure was to drive  to  Ft.




Greely in the evening  two days before sampling or in  the  early




morning one day before, in  order to  set up the influent sampler




to obtain a 24-hour composite.  Sampling was then accomplished




in the early morning on sampling day, packed in an ice  chest, and




driven back to the laboratory for analysis the same  day,  usually




within 3 to 5 hours.   Analysis included BOD, COD, solids  and




nutrients.  pH was performed in the  field with a Porto-matic,




Model 175 meter supplied by Instrument  Laboratories.  Dissolved




oxygen (D.O.) levels were obtained in the field with  a  Model  54




meter supplied by Yellow Springs Instrument  Company.  The  D.O.




instrument was calibrated before leaving the laboratory in




saturated water at the expected lagoon  temperature and  the




calibration checked on return from the  sampling trip.   During the




cold weather, the instrument was kept in a specially  fabricated,




insulated box while obtaining the lagoon D.O. levels.
                                29

-------
Northway Lagoon



Northway lagoon effluent samples were also grab while the  in-


fluent samples were composite.  The composite samples were  ob-


tained from a tap in the discharge line from the lift pump.   Each


time the lift pump operated, a small amount of sample was  forced


through tubing into a collection container.  Generally,  the  same


procedure was followed for Northway lagoon sampling as for  Ft.


Greely.  Samples were collected in the early morning, packed  in


an ice chest and transported back to the laboratory for  analysis


the same day.  Because of the longer distances involved, a  lag


of 6 to 9 hours normally occurred between collection and


analysis.  Analyses were essentially the same as for Ft. Greely.



EIELSON AIR FORCE BASE EXPERIMENTAL AERATED LAGOON



Lagoon Description



The EAFB experimental lagoon (Figure 1) consisted of six cells


operated in series.  During the latter part of the study the


lagoon was converted to four cells operating in series.  It  was


fed raw domestic sewage.  The lagoon consisted of a wood crib


structure with vertical sides and lined with a 20 mil polyvinyl
                                                       *

chloride (PVC) membrane.  Dimensions were 4.6m X 25.2m X 3.7m


deep for an operating volume of 420 m .  Detention time  per  cell


was as follows:
                                30

-------

        \t,4
Figure 1.  Eielson Air Force Base Experimental Lagoon.

-------
     Cell No.              - 1    2    3    4     5     6   Total




     Detention Time (days) - 1.8  2.9  3.6  5.4   7.3   9     30






Flow measurement and control was accomplished with  a  dump tank




and a timer on the feed pump and a "V" notch weir  in  the  lagoon




effluent structure.  In the lagoon, each cell was  fed  from  the




previous cell through a 51mm diameter X 3m long  suction  hose




coiled and hung above the aerators.  The feed temperature was  a




fairly constant 20°C because of heated utilidors.






Initial startup of the lagoon began in September,  1968 with aera-




tion provided by fine bubble diffusers.  These consisted  of 16 mm




(5/8 in.) OD flexible plastic tubing with 8 slits  per  foot  on  top




and a lead keel on the bottom to keep it submerged  (Hinde




Engineering Company, Highland Park, Illinois).   The tubes were




placed perpendicular to the line of flow and supported 40 cm




above the bottom to prevent sludge plugging.








Because of clogging problems and resulting high  compressor




discharge pressures encountered with the perforated tubing, the




lagoon was modified in January 1970 by replacing  the  tubing with




coarse bubble diffusers manufactured by Aer-0-Flow  Corporation,




Florence, Kentucky.  The lagoon was then operated  through May




1972 (over two years) with no change in compressor  discharge




pressure and no maintenance problems due to the  aeration  system.
                                32

-------
The Aer-0-Flow diffuser consisted of a cap which rested  on  a  1/8


inch pipe orifice.  When air was flowing, the cap  was  forced  up


about 1.5 mm and air flowed under the cap and, theoretically,  up


through the small holes in the cap.  When air was  shut off, the


cap would fall back against the orifice and prevent  solids  from


backing up in the system.





Operation Problems



Clogging of the perforated tubing proved to be a problem during


the first year in the first two cells where the solids concentra-


tion was greatest.  Cleaning was accomplished by applying hy-


drochloric acid at a rate of 50 g/m on one occasion  and  applying


hydrogen chloride gas at a rate of 9 g/m on three  occasions.


Each time the compressor discharge pressure would  drop to 0.50

             2
to 0.56 kg/cm  after cleaning  and climb back  to 0.63 to

          2
0.70 kg/cm  within a few days.  Both cleaning methods  were  inef-


fective in the first two cells and replacement of  tubing was


found necessary twice.



In the case of gas cleaning, adequate valving was  not  provided,


and the gas passed through the less restricted tubing  in the  last


4 cells restoring the aeration patterns in those cells but  not


in the first two cells.  Dissolved oxygen levels were  generally


less than 1/2 mg/1 in the first two cells during this  period.
                                33

-------
Problems were also encountered with  leaking  of  the  PVC  liner


during the first summer's operation.   Bentonite  was  added  to  the


first two cells in July and August and  the  lagoon  pumped  down in


•September 1969 when the leakage continued.   Repairs  to  the  lining


were made and the lagoon placed back  in  operation  in October


1969.  Some leakage still occurred which  a  further  addition of


bentonite had stopped by late November  1969.




Minor leakage continued to be a problem  and  the  lagoon  was  pumped


down during the summer of 1970 for more  repairs  to  the  PVC


lining.  Leakage problems somewhat more  severe  were  encountered


during the winter of 1970 - 1971; however,  no attempts  have been


made to adjust the data.





After installation of the Aer-0-Flo  non-clog diffusers  in


January, 1970, the compressor discharge  pressure and temperature

                                                 2
immediately dropped from greater than  0.63  kg/cm   and 90°C  to

         2
0.42 kg/m  and 32°C, and the dissolved  oxygen (DO)  in the  first


two cells rose to more than 5 mg/1.   The  lagoon  was  then  operated


through May 1972 (over two years) using  the  Aer-0-Flo diffusers


with no change in compressor discharge  pressure  and  no  main-


tenance problems due to the aeration  system.


BOD and SS_ Removals




A summary of BOD and SS removals for  the  EAFB experimental  lagoon


is presented in Table 1.  Removal data  for  both  the  perforated
                                34

-------
                                  Table 1.  Performance Summary of Eielson Air Force Base Experimental Lagoon
CO
en
Period Station
Six Cell Operation
First 18 Months Inf
Cell -1
-2
-3
-4
-5
-6
First Year Winter Inf
Fine Bubble Aeration Cell -1
-2
-3
-4
-5
-6
Second Year Winter Inf.
Coarse Bubble Aeration Cell -1
-2
-3
-4
-5
-6
Detention
Time (Days)
Per Cell

-
1.8
2.9
3.6
5.4
7.3
9.0
_
1.8
2.9
3.6
5.4
7.3
9.0
_
1.8
2.9
3.6
5.4
7.3
9.0
Accum.

-
1.8
4.7
8.3
13.7
21.0
30.0
_.
1.8
4.7
8.3
13.7
21.0
30.0
_
1.8
4.7
8.3
13.7
21.0
30.0
Loading
(^BODs/m3-day)
Per Cell

-
177.2
51.5
30.0
11.1
5.5
2.9
_
168.3
47.2
32.8
10.0
4.7
3.0
_
201.1
62.1
33.9
15.7
8.0
3.2
Accum.

-
177.2
67.8
38.4
23.2
15.2
10.6
_
168.3
64.3
36.5
22.1
14.4
10.1
_
201.1
76.8
43.5
26.4
17.3
12.1

Mean

319
151
108
60
40
26
26t
303t
137
118
54
34
27
28t
362
180
122
85
58
29
21

Stand
Dev.*

109
71
47
34
25
11
10
154-553
45
38
26
15
12
13
105
91
56
36
30
10
10

Number
Samples

40
55
58
56
56
51
58
9
17
20
18
17
17
19
21
21
21
21
21
15
21
BOD^
Percent
Per Cell

-
53
28
44
33
35
3
_
55
14
54
37
22
0
_
50
32
30
32
50
30

Removal
Accum

-
53
66
81
87
92
92
_
55
61
82
89
91
91
.
50
66
76
84
92
94
                (Continued)

-------
       Table 1.   Continued
u>
01
COD
Period Station
Six Cell Operation
First 18 Months Inf
Cell -1
-2
-3
-4
-5
-6
First Year Winter Inf
Fine Bubble Aeration Cell -1
-2
-3
-4
-5
-6
Second Year Winter Inf
Coarse Bubble Aeration Cell -1
-2
-3
-4
-5
-6
	 . 	 * 	
Mean

509
262
227
179
142
no
85t
315
249
242
164
129t
121t
112t
568
280
247
239
193
118t
81
Stand
Dev.*

175
106
87
84
83
61
38
176-464
64
77
55
57
55
41
103
71
97
80
87
44
40
Number
Samples

31
46
45
46
44
46
45
6
13
13
13
12
13
13
15
15
15
15
15
15
15
Percent Removal
Per Cell

-
49
13
21
21
23
23
_
21
13
33
21
7
7
_
51
12
3
19
39
32
Accum.

.
49
55
65
72
78
83
_
21
23
48
59
62
65
_
51
57
58
66
79
86
Mean

261
138
143
91
67
39
23+
218+
109
139
61
38
25
18
278
152
172
153
128
45+
23
Stand
Dev.*

128
46
86
67
69
29
12
112
42
63
27
18
10
10
131
51
99
74
82
16
10
SS
Number
Samples

42
58
58
61
55
56
59
11
18
18
18
17
14
17
21
21
21
21
20
21
21


Percent Removal
Per Cell

-
47
0
36
27
42
42
_
50
0
57
37
35
29
_
45
0
11
17
65
48
Accum

-
47
45
65
75
85
91
_
50
36
72
82
89
92
_.
45
38
45
54
87
92
                 (Continued)

-------
      Table 1.   Continued
CO
Detention
Time (Days)
Period Station
Si x Cell Operation
First and Second Inf
Year Winter Cell -1
-2
-3
-4
-5
-6
First and Second Inf
Year Summer Cell -1
-2
-3
-4
-5
-6
Per


1
2
3
5
6
7

1
2
3
5
7
9
Cell

-
.8
.9
.6
.0
.4
.5
_
.8
.9
.6
.4
.3
.0
Accum.

-
1.8
4.7
8.3
13.3
19.7
27.2
_
1.8
4.7
8.3
13.7
21.0
30.0
Load
(q BODs/r
Per Cell

-
192.
55.
32.
14.
7.
3.
_
118.
45.
23.
6.
4.
3.


8
5
5
2
3
7

9
9
6
3
5
3
ing
n3-day)
Accum.

-
192.8
73.8
41.8
26.1
17.6
12.8
_
118.9
45.4
25.8
15.5
10.2
7.2

Mean

347
161
117
71
47
28
24t
214
133
85
34
33
30
29

Stand
Dev.*

no
76
50
35
27
11
11
178-243
77-205
52-409
29-173
19-49
7-45
8-45

Number
Samples

30
38
41
39
38
32
40
3
5
4
4
5
5
5
BOD,

Percent Removal
Per Cell Accum

-
54
27
39
33
27
5
_
38
36
61
0
11
2

-
54
66
79
86
92
93
_
38
60
84
84
86
86
                (Continued)

-------
      Table 1.   Continued
CO
oo
COD
Period Station
Six Cell Operation
First and Second Inf
Year Winter Cell -1
-2
-3
-4
-5
-6
First and Second Inf
Year Summer Cel 1 -1
-2
-3
-4
-5
-6
Mean

496
265
245
204
169
122
99
360
200
170
137
81
71
66
Stand
Dev.*

156
69
87
79
86
58
55
334-404
99-243
42-292
62-188
30-190
44-99
43-80
Number
Samples

21
28
28
28
27
28
28
3
4
4
4
4
4
3
Percent Removal
Per Cell

-
47
8
17
17
28
19
_
44
15
20
41
12
8
Accum.

-
47
51
59
66
75
80
_
44
53
62
78
80
82
Mean

264
132
157
110
87
36(t)
21
192
137
72
30
25
27
25
Stand
Dev.*

136
51
85
74
76
16
10
95-338
87-192
28-173
16-43
11-45
10-45
10-41
SS
Number
Samples

32
39
39
39
37
35
38
4
4
6
6
6
6
6


Percent Removal
Per Cell

-
50
0
30
22
58
42
_
29
47
59
17
0
9
Accum

-
50
41
58
67
86
92
_
29
63
85
87
86
87
                (Continued)

-------
Table 1.   Continued
Detention
Time (Days)
Period Station
Four Cel 1 Operation
Third and Fourth Year Inf
Cell

-
Third and Fourth Year Inf
Winter Cell

-
Third Year Summer Inf
Cell

-


-2
-4
5 & -6T

-2
-4
5 & -el

-2
-4
5 & -6T
Per

_
4.
9.
16.
_
4.
8.
13.
.
4.
9.
16.
Cell


7
0
3

7
6
9

7
0
3
Accum.

_
4.7
13.7
30.0
_
4.7
13.3
27.2
.
4.7
13.7
30.0
Loading
(q BOD5/m3-dayj
Per Cell

_
39.6
9.4
3.4
_
40.4
10.9
4.4
.
45.5
7.9
2.9
Accum.

-
39.6
13.6
6.2
—
40.4
14.2
6.4
„
45.5
15.6
7.1
BOD5

Mean

186t
85
55
33
190t
94
59t
40
214
71
47
19
Stand
Dev.*

61
26
28
15
74
21
20
11
56
17
22
10
Number
Samples

61
61
62
60
31
31
31
29
15
15
15
15
Percent
Per Cell

-
54
35
15
_
51
33
31
_
67
34
60
Removal
Accum

-
54
70
83
_
51
69
79
_
67
78
91
          (Continued)

-------
Table 1.   Continued



COD

Stand Number

Period Station
Mean
Dev.* Samples



Percent Removal
Per Cell
Accum.
Mean

Stand
Dev.*
SS
Number
Samples

Percent
Per Cell

Removal
Accum
Four Cell Operation













*
t
1
Third and Fourth Year Inf
Cell -2
-4 ,
-S&-6?
Third and Fourth Year
Winter Inf
Cell -2
-4
-5&-6I
Third Year Summer Inf
Cell -2
-4
-5&-6I
320
202
138
95

320t
215
162t
125t
317
165
94
47
The range is shown where the number of
Adjusted from probability plot.
Cell 5 Removals not shown due to

sample
98
69
65
47

no
38
52
30
76
44
44
5
62
60
62
61

32
30
31
31
15
15
15
15
samples collected is

collection

problems
-
37
32
29

-
33
25
19
_
48
43
18
-
37
57
70

-
33
49
61
_
48
70
85
145
90
54t
29

130t
101
69t
44
167
73
60
14
88
44
33
21

70
33
31
18
43
49
90
13
56
57
57
58

28
27
28
28
14
15
15
15
-
38
40
46

-
23
32
29
_
56
18
39
-
38
63
80

-
23
47
66
„
56
64
92
less than ten.

during this

period.











-------
tubing and Aer-0-Flo diffuser systems operated  under essentially




the same conditions indicate little effect on process  performance




by the change in aeration devices,  (Figure 2).   An exception  is




the approximately 5 percent lower removals at around ten days




detention time associated with the  coarse bubble diffuser.   This




may have been due to a stirring up  or shifting  of the  bottom




sludge caused by the change in aeration devices.  Overall  BOD




removal efficiencies for 4 cell and 6 cell operation are




presented in Figure 3 along with  the maximum  ice buildup ex-




perienced during the winter of 1970.  The winter data, referred




to later, has been adjusted for average ice buildup using  1/2  of




the maximum thickness reported for  each cell.






The much lower removal efficiencies for the 4 cell operation  has




been attributed to a combination  of aging due to sludge buildup




and the provision of fewer cells  in series.   Both of these con-




siderations are discussed later.








Winter and summer BOD removals and  effluent SS  levels  are  com-




pared in Figure 4.  Best removals were obtained  during the first




winter operation (6 cell) reaching  greater than  90 percent at




around 20 days dentention. Summer removals for  the first year  ap-




proach those for the winter at less than  15 days and then  level




off at around 86 percent.  This can be ascribed  to algae growth




since algae were present in cells 2 through 6 during that  summer.




It should be noted that the first summer  removals are  based  on
                                 41

-------
    100
    90
    80

O


cc

Q
O
CD
    70
    60
    50
           Fine Bubble  Diffuser
       o
                                     Coarse  Bubble  Diffuser
                            10         15         20

                           Detention  Time  (Days)
25
30
Figure  2.  EAFB Experimental  Lagoon performance with  fine bubble and coarse
bubble  diffuser systems.
                                    42

-------
  100
   90
   80
 o
 E
 o>
 cr
o
00
   70
   60
   50
          T
                            Maximum  Ice  Thickness

                                 Winter  1970
                        j
     5


     4


     3
                                                                     cu
                         10                 20

                          Detention  Time (days)
30
Figure 3.  EAFB  Experimental  Lagoon performance with 6 cell  and 4 cell
operation.
                                  43

-------
       100
       90
80
     a;
     >
     o

     a>
    a:
    Q
    O 70
    CD  'U
       60
        50
       100
        80
     cr>


    I  60
    cn

    I 40
     o
    oo


    1  20
     c
     a>
     CL
         0
                                 o

                                 a
6 Cell  winter

6 Cell  summer

4 Cell  winter

4 Cell  summer
                             10

                            Detention  Time
                                        20
                      30
Figure  4.  EAFB Experimental  Lagoon winter and summer percent BOD removal
and SS  remaining vs. detention  time.
                                   44

-------
5 data points only.  The reduced BOD removal efficiency  during




summer is not considered the result of bottom sludge activity




during the first year but may have been the result of a  reduced




degree of settling.  Examination of the bottom sludge in cell 6,




during the fall of 1969, indicated only a thin layer of  floc-




culated algae.






The 4 cell summer data shows lower removals at approximately 15




days but increases to greater than 90 percent at 30 days.   The




lower removal at 15 days is attributed to aging of the lagoon




while the greater removals at 30 days are attributed to  a  fil-




tering action.  The liquid in cells 5 and 6 of the EAFB  lagoon




was dark green with algae during June and part of Duly 1971.




Chlorella appeared to be the predominant algae species.  Green




filamentous growth was also thick with stringers over 10 feet




long attached to feeder air lines.  During July a reduction in




color was accompanied by the appearance of Daphnia.  Effluent




BOD's of less than 10 ppm were measured in late July and early




August and were attributed to the Daphnia and the filtering ac-




tion of the filamenmtous algae.  Increased settling may  also have




contributed to the higher removals.






Algae Growth






Chlorophyll measurements were made on the lagoon in the  early




summer of 1969 (Figure 5).  The highest chlorophyll reading in




the 6th cell was 810m-SPU/m3 (mil 1i-Specific Plant Units/meter
                                45

-------
      600
      500 -
      400 -
   Q_
   CO
      300 -
   CL
   o
   o
                                           x- Suspended
                                          s     Solids
                                                               - 100
      200 -
      100 -
 cr>
^E

 to


"o
CO

-o
 cu
                                                                      Q.
                                                                      CO
                                                                      3
                                                                     CO
                           10                20

                           Detention Time (days)
Figure  5.  EAFB Experimental Lagoon chlorophyll  and suspended  solids vs.
detention time.
                                  46

-------
cubed).  The major algae growth began after approximately  10  days




detention time and followed a typical growth  curve.   Information




is available for only 30 days detention  time  and  followed  a




typical growth curve, but presumably the curve  would  peak  and




begin to decline with time.






Coliforms






Fecal indicator organisms measured  in the effluent  of  the  EAFB




6 cell, 30 day lagoon during the  summer  of  1969 were  (Clark et




al . ,  1970):






                                    JULY          AUGUST






       Total coliform               5500          1200






       Fecal coliform                440            770






       Fecal enterococci             126             64






Associated effluent  temperatures  were 15 -  16°C and  the  pH varied




from  7.0 to 8.4.






Total coliform removals found in  the EAFB experimental  lagoon  are




presented in Table 2.  As Expected, the  dieoff  of coliform bac-




teria is significantly more rapid  in the summer.  The  6  cells  in




series also resulted in higher  dieoff rates than  the  4  cells  in




serie s .
                                47

-------
                                  Table 2.  EAFB Experimental Lagoon  Total  Coliform Removal  Results*
-Pi
CO
Cell Number
Period Influent
Six Cell Operation
Winter
1/22/70-3/25/70 6.5 X 107
% Removal
Four Cell Operation
Winter
1/29/71-3/24/71 &
1/5/72-3/29/72 7.3 X 107
% Removal
Four Cell Operation
Summer
6/9/71-9/8/71 1.1 X 108
% Removal
1


1.3X107
80



1.2X107
84


8.2X106
93
2 3


6.7X106 4.1X106
90 94



1.8X106
98


3.9X106
99.6
4 5


1.4X106 3.0X105
98 99.5



1.1X106
98


2.2X104
99.98
6


1.4X10"
99.98









                *  Values are geometric means

-------
Nutrients






Nutrient removals for the EAFB experimental lagoon  show  little




removal of NH_-N or T-N during winter operations and  significant




removals in summer (Table 3).  T-N removals in summer  were  less




than NH,-N, indicating a conversion of nitrogen to  the organic




form by algae.  The phosphorus data indicate the net  annual




removals are zero.  The phosphorus apparently had previously  ac-




cumulated in the bottom sludge and was being released  to  the




lagoon liquid by anaerobic action.  Also the inherent  inaccuracy




of the organic phosphorus analysis may have contributed  to  the




negative removal results.









FORT GREELY LAGOON






Lagoon De scr iption






Because of the success with  the Aer-0-Flo diffusers in the  pilot




facility, it was decided they should be demonstrated  in  a full




scale lagoon.  This led to an agreement with the U.S.  Army,




Alaska (USARAL), in the summer of 1971 which allowed  AER5 to




modify part of the waste treatment lagoon at Ft. Greely.






The Ft. Greely lagoon was constructed in 1969 and had  two cells




which could be operated in series or in parallel.   Each  cell  was




separated into two smaller cells by a baffle which  extended  from




the bottom to about 0.3 m below the water surface.  The  lagoon
                                49

-------
Table 3.   EAFB Experimental  Lagoon  Nutrient  Removal Summary
Period
Six Cell Operation
Winter






% Removal
Summer






% Removal
Four Cell Operation
Winter



% Removal
Summer



% Removal
Station

Inf
Cell -1
-2
-3
-4
-5
-6

Inf.
Cell -1
-2
-3
-4
-5
-6


Inf
Cell -2
-4
-6

Inf
Cell -2
-4
-6


HN3-N (mg/1)

16
15
15
17
17
17
17
(-6)
29
25
28
27
26
20
15
48

14
20
22
20
(-43)
24
28
25
15
38
Nutrient
T-N (mg/1)

22
21
21
26
26
22
21
5
38
32
33
32
28
30
33
13

19
27
28
26
(-37)
30
27
26
25
13
0-P (mg/1)

6
8
8
9
9
9
10
(-67)
29
36
36
39
37
37
38
(-31)

7
12
10
11
(-57)
8
6
10
11
(-38)

T-P (mg/1)

10
13
14
15
14
15
16
(-60)
44
49
50
48
47
46
41
7

9
13
13
13
(-44)
10
12
10
13
(-33)
                          50

-------
was of earthen dike construction lined with PVC  film  and  had  15cm




of sand covering the bottom.  The upper slope was covered  with




gravel.  Each principal cell measured 61m x 61m  at  the base.   The




side slope ratio was 2 horizontal by 1 vertical.  Volume  was




29,000 m  at an operating depth of 3 m.  The lagoon treated




domestic sewage which has a fairly constant temperature of  20°C




because of heated utilidors.






The aeration system of one half of the lagoon was modified  in




Duly 1971 (Figure 6).  Two clusters of Chicago Pump Shearfusers




(Chicago Pump, FMC Corporation, Chicago, Illinois)  were installed




in one cell (Figure 7).  Shearfusers consist of  a box about  18 cm




square with a 2.5 cm air injection orifice entering the side.  As




the air rises in the box, water is pulled in through  the  hole  in




the other side and the resulting shearing action causes the  air




to break up into smaller bubbles. Aer-0-Flo diffuser  clusters




were installed in the second cell (Figure 8).






The two principal cells of the lagoon were operated in parallel




for one year beginning in October of 1971.






Aerator Performance






Figure 9 gives information on the perforated tubing aerator  per-




formance.  Some of the variability of the data is due to  clogging




problems encountered with the perforated tubing.  That is,  as  the




tubing began clogging, more air was diverted by  the operator  to
                                51

-------
CJl
ro

^
\N
\

















x- —
k-^)
•N.
^







-

-
-
/
.
I









C



,4
1









^l
^

•-•>,

(
\


.. — •

(T
vi
^






d
L_ _
X.
\J
-e>- -
— 1
7)
•° 1
1
1
1
i
1
®|

__i



y



— x_


)
i,'

/



ft!
r




V






Iflf


X
f^i
«-^
•fri~
viy


— —

T)
J^
x^






s




]



k
1









s
/•
V







-®










\


















/





fl
y




a
0











7
R
5



^Q\
O
1
7
i


°nn'







o'
»
• 1





g
a
y












3
8

© r


3
0








X
~"""**x^
^




	
-w



M
^^^
^/
^-PS'-**




N

\









/

/






\
\









/
/^








2



?(





2





LEGEND
1 Laboratory Building
2. Manhole -Parshall
Flume

3. Wet Well and Lift
Station
4. Chlorine Contact
Chamber
5. Effluent Line
6. Influent Header
7. Air Header Box
8. Aeroflow Diffusers
9. Shearfusers
10. Baffle
II. Dock
30'





5'
k




     Figure  6.   Plan  view of Ft.  Greely coarse bubble aerator installation.

-------
en
co
      Figure  7.   Chicago Pump Shearfuser cluster.

-------
tn

     Figure 8.   Aero-0-Flo non-clog diffuser cluster.

-------
  o
                I    I     I     I    I
                                              I    I     I     I    I
                I    I     I     I    I     I     I
                I     I    I     I     I    I     I
                                                   I    I     I     I
        100




        75
   k_
   O C(-v

  O 2^ 3U



  -^    25




         0
                i     I    I     I     I    I     I
                                                   I    I     I     I
Q.

E
c
o
o

01
o
        20




         10




         0
                         '     '     '    '     '
                 Oct  Nov Dec  Jan  Feb  Mar  Apr  May June July  Aug  Sep
Figure 9.   Ft.  Greely fine bubble  diffuser performance  data.



                                       55

-------
the coarse bubble aerator side to reduce the discharge  pressure


of the compressors.  The trend was detected three months  after


startup of the lagoon.  Although the discharge  pressure ranged

                 2
around 0.63 kg/cm  in May, the air flow through  the  perforated


tubing was so low that the lagoon became anaerobic.   The  tubing


was cleaned with hydrochloric acid around the first  of  June.   The


cleaning plus algal activity accounts for the high DO levels


during that month.  Air flow data was not obtained in early  July.



The low DO level which occurred in July was not  due  to  low air


flow but to bottom sludge turnover.  This turnover was  caused by


heavy sludge layers which underwent increasing  anaerobic  action


as the temperature increased until the resulting gas  production


caused the sludge to rise and disperse anaerobic products  (or-


ganic acids, etc.) into the aerobic liquid above.  The  result was


a drastic decline in algae and a great increase  in DO uptake


which reduced the lagoon DO level to zero.  This lasted for  a few


days after which time the DO level began to increase.   This


phenomenon usually occurs each year after spring breakup  in  an


aerated lagoon in which sludge accumulates with  little  decomposi-


tion over the winter months.



Figure 10 presents performance information for  the coarse  bubble


diffuser side of the lagoon.  The liquid temperature  and  ice


cover were about the same as for the perforated  tubing  side  ex-


cept the ice cover did not reach 100 percent.   Ice thickness  in
                               56

-------
  o
  §•.§
       12

       10

       8
     ^ 1.0
    ro
     M—
    . O 0.8
< O 0.4

      0.2

      100

      75
 o>

8 & 50
 CD
.2    25

       0
                    I     l     I
I     I  o  I    I
                l     l    i     i     i     i     i    i     i     i     i    i
                              i     i     i     i    i     i
  Q.
  E
       20

       10

       0
                         I     I     l     I     I    l    J
                 Oct  Nov Dec   Jan  Feb  Mar  Apr  May June  July  Aug  Sep
Figure 10.   Ft.  Greely coarse bubble  diffuser performance  data.

                                       57

-------
both lagoons was never more than  a  few  inches.   The  air  flow to




the coarse bubble diffusers increased during  the  period  of




clogging of the perforated tubing.   The  low  DO  point in  early




Dune was again due to the sludge  turnover  phenomenon.   The  low




DO point in August occurred when  the first 16  lengths  of per-




forated tubing at the influent were  manually  cleaned (reper-




forated) with sharpened screwdrivers.   This  method of  cleaning




reduced the pressure drop through the tubing  to  such a  degree




that the system required rebalancing of  air  flow  between the




coarse bubble diffusers and the perforated tubing.






Winter and summer aeration patterns  for  the  coarse and  fine




bubble aerators are shown in Figures 11  through  14.






BOD and 55 Remov als






A summary of the lagoon performance  is  included  in Table 4.   The




difference in detention times was due to an  imbalance  of flow to




the two sides.  Very little difference  in  removals between  the




coarse and fine bubble diffuser sides is indicated in  spite  of




the difference in detention times and loadings.   An  exception was




the higher effluent 55 for the coarse bubble  side effluent,




presumably due to higher algae production  for  that side. A




somewhat higher mixing rate caused  by the  course  bubble  diffusers




may also have contributed to the  higher  55 values.
                               58

-------
CJ1
vo
    Figure 11.  Fine bubble diffuser summer  aeration  pattern.

-------
CTi
O
    Figure  12.   Fine  bubble diffuser winter aeration pattern,

-------
Figure 13.  Coarse bubble diffuser  sunnier aeration  pattern.

-------
en
l\3
   Figure  14.   Coarse  bubble  diffuser winter aeration pattern.

-------
                     Table 4.   Performance Summary of Ft.  Greely Aerated Lagoon
Detention
Time (Days)
Period Station
Third and Fourth Years Inf
Coarse
Fine
en
co Third Year Winter Inf
Coarse
Fine
Fourth Year Summer Inf
Coarse
Fine
Per Cell

26
39
.
25
38
_
29
43
Accum.

26
39
.
25
38
_
29
43
Loading
(q BOD,/
Per Cell

7.3
4.9
.
7.6
5.0
_
6.6
4.5
m3-day)
Accum.

7.3
4.9
.
7.6
5.0
„.
6.6
4.5

Mean
190
39
37
189
37
33
192
43
45
Stand
Dev.*
137-274
24-72
27-56
164-204
25-48
27-39
137-274
24-72
34-56
Number
Samples
9
9
9
6
6
6
3
3
3
BOD 5
Percent Removal
Per Cell Accum

80
81
.
80
82
_ _
78
77
(Continued)

-------
       Table  4.   Continued
CT>
COD

Period
Third and Fourth Years


Third Year Winter


Fourth Year Summer



Station
Inf
Coarse
Fine
Inf
Coarse
Fine
Inf
Coarse
Fine

Mean
358
125
120
342
117
114
352
143
138
Stand
Dev.*
61
26
15
254-407
102-128
100-127
276-424
97-211
125-159
Number
Samples
15
15
15
9
9
9
4
4
4
Percent Removal
Per Cell Accum.

65
67
_
66
67
. —
59
61

Mean
153
47
41
146
38
30
161
73
57
Stand
Dev.*
29
28
15
110-170
19-51
26-49
97-218
42-141
33-78
SS
Number
Samples
15
15
15
9
9
9
4
4
4

Percent Removal
Per Cell Accum
.
69
73
-
74
75
-
55
65
         The range is shown where the number of samples collected was less than 10.

-------
51udge Accumulation






Sludge depth measurements were made on  the coarse  bubble  side  of




the Ft. Greely lagoon in July 1971 while  the  lagoon  was  drained




for modification.  Sludge accumulation  over  the  perforated  tubing




near the influent averaged about 50 cm  along  the  influent




manifold and tapered to a depth of 5 cm  approximately  15  m  from




the influent edge of the lagoon.  The remainder  of cell  1 was  ap-




proximately 15% covered with 3 - 5 cm of  sludge.   The  second  cell




was approximately 50% covered with 3 -  5  cm  of  sludge.






Sludge core samples were taken near the  influent  manifold at




various times during the project (Table  5).   The  core  samples  ap-




peared to be preserved essentially as deposited  and  were  well




compacted which may account for the relatively  high  percent




solids.






Two temperature probes were placed in the  sludge  near  the in-




fluent manifold at approximate depths of  18  cm  and 48  cm.   The




sludge depth at this point was 50 cm.   The sludge  temperatures




recorded along with the lagoon liquid temperature  are  shown  in




Figure 15.  The probe at 18 cm in depth  ceased  functioning  after




the May measurement.  The high temperature recorded  in  May  is




probably due to high influent temperatures which  remained at  20°C




or greater throughout the project.  Sufficient  gas had  ac-




cumulated to cause sludge turnover to occur  about  July  10.
                                65

-------
Table 5.  Ft. Greely Aerated Lagoon Sludge Analysis
Near Influent -

cr>
cr>


Date
12/21/71
5/19/72
6/16/72
11/30/72
Bottom
% Total
Solids % Volatile
6
-
20
67
-
40
Cell 1
Middle
% Total
pH Solids % Volatile
5.6 19
31
5
5.6
47
40
54
-
Near Effluent
Top
% Total
pH Solids % Volatile
5.9 21
22
17
53
58
50
9
5
Cell
* Total
pH Solids
6.3
1
6.0 31
1
% Volatile
~
69
19
Near Effluent
Cell 2
% Total
pH Solids
_ _
37
67
% Volatile
~
10
3
PH
~
-
-

-------
cr>
          22
          20
       o
          16
          14
          .0
          12
        S  10
        Q.


        o>
           8
           0
                  i      r
  Sludge Depth - 50cm


o  Approx. 2cm Above Bottom

^  Approx. 33cm Above Bottom


•  Liq,uid Temperature
              Nov   Dec   ' Jan    Feb    Mar    Ap    May   June   July    Aug   Sept    Oct    Nov    Dec
     Figure 15.   Ft.  Greely  aerated  lagoon sludge  and liquid  temperature, 1971-1972.

-------
As expected, the sludge temperatures lag the liquid  temperatures




and do not peak as high in the summer.  The deeper sludge  did  not




reach a sufficiently high temperature for anaerobic  decomposition




until late May and June , even with the high temperature  influent




at Ft. Greely.  The period of higher temperatures lasts  for  3  or




4 months at the most.






Algae Growth






The variation of suspended solids and algae during the summer




season for the Ft. Greely lagoon is shown in Figure  16.   These




values are for the coarse bubble side effluent and are very




similar to the fine bubble side values.  In both cases the algae




levels built up very high during June and decreased  sharply  after




the bottom sludge turnover which occurred in early July.   As may




be expected, the filtered BOD levels show that good  effluent




quality can be obtained if algae removal can be accomplished.






Nutrients






Ft. Greely lagoon nutrient removals follow a pattern similar to




those for the EAFB Experimental lagoon.  Winter NH,-N and  T-N




values show no change through the lagoon and summer  operation




shows significant removal (Table 6).  The phosphorus data  shows



no net reduction.
                                68

-------
 500|-
 4001-
  3001-
o  Unfiltered BOD (mg//)
   Filtered BOD (mg//)
n  Chlorophyll (m-SPU/m3)
   SS (mg//)
  200 h-
                          July     Aug
                          Sample dates
                             Nov
Figure 16.   Ft. Greely aerated  lagoon BOD, chlorophyll and  suspended  solids
vs. summer sampling dates.
                                 69

-------
      Table 6.   Ft. Greely Lagoon Nutrient Removal Summary
Nutrients
Period Station NH^-N
Winter Inf 15
Coarse 16
% Removal (-7)
Fine 16
?o Removal (-7)
Summer Inf 16
Coarse ID
?o Removal 38
Fine 12
% Removal 25
T-N
22
22
0
21
5
21
14
33
16
24
0-P
6
9
(-50)
8
(-33)
3
7
(-133)
7
(-133)
T-P
9
9
0
9
0
7
8
(-14)
8
(-14)
NORTHWAY LAGOON






Lagoon Descript ion






The Northway Lagoon consists of a wood crib structure with ver-




tical sides and sealed with bentonite.  Dimensions are 12.8 m X




16.5 m X 2.3 m for an operating volume of 480 m .






A longitudinal baffle splits the lagoon into two equal cells,




each 6.4 m wide.   Feed consisted of domestic sewage from the




Federal Aviation  Administration (FAA) station, comprising 14




family units.   The feed temperatures were estimated to vary from




2 - 24°C.




                                70

-------
The lagoon was placed in operation during September  1965  using




the perforated plastic aeration tubing.  In September  1970,  one




Air Gun aerator (Aero-Hydraulic Corp., Montreal, Quebec)  was  in-




stalled in each cell.  These air guns consist of a 30.5 cm




diameter by 1.5 m long submerged vertical plastic pipe with  an




air chamber at the lower end.  Air is pumped into the  chamber and




builds up until released by a siphoning effect  through the  tube.




The rising air bubble "piston" draws in water from holes  in  the




pipe located just above the air chamber and a pumping  action  oc-




curs.  Air gun aerators are designed for use in deeper lagoons




(4 - 5 m) and are designed to provide mixing as well as oxygena-




tion .






The air gun aerators had been furnished by the  manufacturer  on




a loan basis and had to be returned during the  summer  of  1972.




Rather than attempt to rejuvenate the perforated tubing,  pipe




stub nozzles were placed in the lagoon and connected to the  air




headers.  A check in October 1972 indicated the DO levels  in  the




lagoon to be near saturation, and the total detention  time  to be




about 25 days.









BOD and Sjs Removals






Overall BOD removal from the third through the  eighth  year  was




approximately 86 percent which compared very well with the  other




lagoons investigated (Table 7).  A comparison of the third  and
                                71

-------
                                        Table  7 .  Performance Summary of Northway Aerated Lagoon
ro
Period
Third through Eighth Years


Third Year


Eighth Year


Third through Eighth Year
Winter Period

Detention
Time (Days)
Station
Inf
Cell -1
-2
Inf
Cell -1
-2
Inf
Cell -1
-2
Inf
Cell -1
-2
Per Cell
_
20.0
20.0
_
22.0
22.0
_
14.5
14.5
_
12.3
7.7
Accum.
_
20.0
40.0
_
22.0
44.0
_
14.5
29.0
_
12.3
20
Loading
(g BOD^/m3-day)
Per Cell
.
13.1
2.6
.
10.8
2.6
_
14.7
2.3
_
24.2
7.8
Accum.
_
13.1
6.5
_
10.8
5.4
_
14.7
7.3
_
24.2
14.9

Mean
261
51
37
238
56
30t
213
34
31
297
60
49

Stand
Vev.*
73
17
15
140-330
34-82
13-67
198-228
30-38
19-52
195-380
42-82
24-67

Number
Samples
11
13
19
4
5
7
2
2
6
6
7
8
BODs

Percent Removal
Per Cell
„
81
27
_
76
47
_
84
9
_
80
18
Accum
_
81
86
_
76
87
_
84
85
.
80
84
                  (Continued)

-------
       Table 7.   Continued
CO
COD
Period
Third Through Eighth
Years

Third Year


Eighth Year


Third through Eighth
Years
Winter Period
Station
Inf
Cell -1
-2
Inf
Cell -1
-2
Inf
Cell -1
-2
Inf
Cell -1
-2
Mean
479
150t
136t
405
208
168
502
158
116
469
150t
147t
Stand
Dev.*
130
26
32
237-542
97-406
118-231
484-520
150-165
76-146
237-691
120-406
118-231
Number
Samples
10
10
14
3
3
3
2
2
6
6
6
7
Percent Removal
Per Cell

69
9
_
49
19
_
69
26
_
68
2
Accum.

69
72
_
49
58
_
69
77
_
68
69
Mean
206
61 1
39t
164
104
30
151
53
29t
233
63t
47t
Stand
Dev.*
130-353
49-136
17
131-196
71-136
25-34
130-172
50-56
18-66
131-353
49-136
25-93
SS
Number
Samples
9
9
13
2
2
2
2
2
6
6
6
7


Percent Removal
Per Cell
_
70
37
_
37
72
_
65
45
_
73
25
Accum
„
70
81
_
37
82
_
65
81
-
73
80
       *    The range is shown where the number of samples collected is  less  than  ten.



       t    Adjusted from probability plot.

-------
eighth years performance showed little aging effect  over  this




period.  Detention time for this period averaged  40  days.









Bottom 51udge






Analysis of sludge samples from the Northway Lagoon  are  shown  in




Table 8.






In 3une 1967 and March 1971, sludge core samples  were  examined.




The sludge appeared to be preserved exactly as deposited.




However, in August 1967 and May 1968, bottom samples had  a




definite black appearance and the physical characteristics  of




partially digested sludge.  Methane production apparently oc-




curred during the summer of 1967 causing the sludge  location  to




shift between the August 1967 and May 1968 sampling  dates.   The




maximum bottom sludge temperature recorded at Northway was  19QC.






Samples taken at Northway during March 1970 indicate an  average




sludge accumulation of approximately 15 cm in the  first  cell  and




approximately 8 cm in the second cell.  This indicates an ac-




cumulation rate of 2.5 cm per year for 4.5 years  or  approximately




255 liters per 1000 people per day, which is in the  low  range  of




observed rates for stabilization ponds (Clark et  al.,  19?0).   Due




to compaction, consolidation, and digestion the long range  ac-




cumulation may be less.
                                74

-------
         Table 8.  Northway Aerated Lagoon Sludge Analysis





Cell 1                                          Cell 2
Date
03/30/70
03/17/71
05/24/72
10/06/72
Ave
% Total
Solids
13
9
12
12
12
% Volatile
44
44
67
45
50
COD
pH mg/g/ Dry Wt.
6.8 92
54
110
7.3 95
88
% Total
Solids
-
42
4
14
20
% Volatile
-
7
63
17
29
COD
pH mg/g Dry Wt.
-
44
34
7.6 59
46

-------
In late March 1970, a 5 cm diameter bottom sludge core  sample




from the first cell, Northway lagoon, was sectioned  and  analyzed




for fecal indicator bacteria (Clark et al. 1970).   The  23  cm  core




was cut in three sections as follows:  7.6 cm bottom,  13 cm




middle, and 2.5 cm top layer.






MPN counts on a per wet gram basis were as follows:






                              No. of Organisms x  10






                              TOP    MID   BOTTOM




Presumptive total coliform    4.9    49     22.1




Confirmed total coliform      3.3    13     13




Fecal Coliform                2.4     4.9    3.3




Presumptive enterococci      13     221    172




Confirmed enterococci        13     221    172






It appears that the sludge located deeper in the  core  has  a more




favorable environment for concentration and preservation of fecal




organisms even though the sludge temperature was  less  than  1°C.




Four additional sludge cores were taken.  Three had  pH  readings




of 7.0 to 7.5 while only one had a pH of 5 to 6.  The  moisture




content averaged 90 percent.






Results from 2.5 cm diameter bottom sludge cores  obtained  from




both cells during March 1971 were as follows.
                                76

-------
MPN counts on a per wet gram basis were:


                             No. of Organisms x  10

                               Cell 1     Cell 2

Presumptive total coliform      130         1410

Confirmed total coliform         79          140

Fecal coliforms                   3.3       insufficient  media

Presumptive enterococci         130          94

Confirmed enterococci            33          94
Confirmed enterococci
  (Counts/mg. volatile solids)   83         2300


As compared to 1970 the coliforms appear to  be composed  of  a

smaller fraction of fecal coliforms.  Also  the enterococci  level

appears to be much lower.  The 1971 results  indicate  that the

sludge in cell 2 is well digested but still  harbors many enteric

bacteria.


Nutrients


Nutrient removals for the Northway lagoon show essentially  the

same results as the EAFB Experimental and Ft. Greely  lagoons

(Table 9).  The phosphorus was not affected  and  the total

nitrogen removal was insignificant.
                                77

-------
   Table 9.   Northway aerated lagoon nutrient  removal  summary
Northway Overall Feed


                 Cell 1


                 Cell 2
                                NH3-N
19


30


30
T-N




 35


 33


 32
0-P




  7


 12


 12
T-P




 12


 13


 12
EAGLE RIVER LAGOON




Lagoon Description




The Eagle River Lagoon had two egual  size  principal  cells which


could be operated in series or parallel.   Each  principal cell


measured 30 m X 12 m at the base and  was divided  into  two smaller


cells by a baffle below the liquid  surface.  Total  lagoon volume


was 9,500 m"  at an operating depth  of  4.6  m.   The  lagoon was con-


structed of an earthen dike with a  side  slope  ratio of 2:1 and


a liner of butyl rubber.  Aeration  was provided by fine bubble


type Hydro-Ceramic diffusers which  consist of  PVC  tube with


porous ceramic stones inserted 0.3  m  apart.   Each  stone provides

            2
about 0.6 cm   of surface area.




The lagoon treated domestic waste and  also served  two  laundry


facilities which contributed a significant portion of  the load.


Feed temperatures ranged from around  5°C in  the winter, to a max-


imum of 15°C  during the warmer months.


                                78

-------
Operation Problems



Since the lagoon began operation,  the  aeration  system  has  been


plagued with problems which have contributed  to  the  poor  perfor-


mance.  Most of the problems occurred  when  the  diffusers  became


clogged and high pressures developed  in  the  system.   The  glued


joints of the PVC piping have tended  to  pull  apart  or  break  and


a number of the porous stones have blown  out.   The  system  has


been described as fragile and unreliable  (R.  Hutson,  personal


communication, 1976).  Failures which  occur  in  the  winter  cannot


be repaired until summer.



The lagoon was placed in operation in  the late  fall  of 1971  with


only one side in operation.  The second  side  was  placed  in opera-

                                                                 2
tion in the spring of 1972.  Blower pressures  were  at  0.56 kg/cm

                                               2
at startup and gradually climbed to 0.91  kg/cm   which  forced


draining of that cell in July 1972 for  inspection  (Mike  Pollen,


Personal Communication,  1972).  On inspection  the  ceramic  dif-


fusers were found to be  clogged with  a  matting  of  lint,  hair and


solids.



Cutting a cross-section  of the  diffuser  showed  small  particles


of lint and hair imbedded in the diffuser to  a  depth  of  approx-


imately 3.2 mm.  Direct  applications  of  concentrated  hydrochloric


acid and scraping removed a large  portion of  the  material  but


deeply imbedded material reguired  cleaning  of  individual  pores.


The material was felt to have been forced into  the  diffuser  when
                                79

-------
the blowers were shut  off  for  maintenance purposes, allowing


water to back up in  the  aeration  system.



The diffusers were cleaned  in  the  field by brushing and washing


with mild detergent  soap.   Blower  pressures were at about


0.60 kg/cm2 in  October  1972,  and  the  system was performing  satis-


factorily.  By  .June,  the pressure  had  begun to build up again,


although not  to  the  levels  previously  experienced.  Visual  obser-


vation  had shown the  aeration  pattern  was obviously deterio-


rating.  The  diffusers  were  cleaned  at the end of June by in-


troducing toluene  at  a  rate  of 34  g/m  and hydrochloric acid at


a  rate  of 189 g/m  at  the instruction  of the diffuser manufac-


turer.   The hydrochloric acid  cleaning was effective since  a good


aeration pattern was  established  and  the  blower pressure dropped

                   7
back to  0.56  kg/cm  .   The  toluene  cleaning was ineffective.





At  this  time  the lagoon  was  drained  and sludge deposits were


found as shown  in  Figure 17,   The  intensive aeration provided in


the first cell  due to  the  high depth  vs width  ratio of the  lagoon


forced  sludge carryover  to  the  other  side of the baffle.  Sludge


deposition occurred  in  a less  intensive aeration area near  the


effluent discharge pipe.   The  sludge  layer was not compacted


(high percentage of  water)  and  the  level  was at the bottom  of the


effluent pipe or at  0.45 m.
                                 80

-------
                                  74'
co
      134


100'
1


f


40'

.-Lesser si
V layer
13 rows
aeration
tubing
i i
10'

3' square
ing at baffle
bottom.
,47 rows of.
aeration tub-
ing.
f ^*"-^.

udge \
open-///;
// At
//
\
\ 1
i /
ii
ii
Effluent cover box
/
If JVIajor sludge \
/ \ layer \
^
Inlet-^
Wiiii'

:•::•':. '-'•
Duplicate
Aeration
System




/
Baffle
surfac

below liquid
e
     Figure 17.  Eagle River  lagoon sludge blanket.

-------
In October,  1973 the flow pattern was changed from series  to




parallel.   In May,  1974 the flow pattern was changed back  to




series with  the result that very high suspended solids  levels




were experienced in the effluent.  These solids were apparently




resuspended  by the  relatively higher flows through the  lagoon




cells during series operations.






One principal cell  of the lagoon was drained during  the  summer




of 1974 for  repairs to the aeration system and a portion of  the




ceramic diffusers were replaced with Aer-Q-Flow aerators.




Similar repairs and replacement of aerators in the other prin-




cipal cell were completed in the summer of 1975.  Initially  the




cap on the new diffusers had a tendency to blow off  at  relatively




high air pressures.  The manufacturer provided redesigned  dif-




fusers for replacement which have operated very well (Richard




Hutson, Personal Communication, 1976).






BOD and SS Remov als






A summary  of operating results beginning in September 1972




through March 1976  are presented in Table 10 and Figure  18.   The




worst performance results occurred during the slimmer months  and




were apparently due to four causes:  algae production,  changing




from parallel to series operation, performance of necessary




repairs during the  warm summer months, and dumping of septic  tank




wastes into  the system.
                                82

-------
                                          Table 10.   Eagle  River Aerated Lagoon Performance Summary
CO
CO
Period
Second Year Overall
Series Operation
Second Year Winter
Series Operation
Second Year Summer
Series Operation
Third Year Winter
Parallel Operation
Third Year Summer
Single Cell Operation
Fourth Year Winter
Series Operation
Fourth Year Summer
Single Cell Operation
Fifth Year Winter
Series Operation
Detention
Time (Days)
Station
Inf.
Eff. 18.2
Inf
Eff 16.6
Inf
Eff 19.4
Inf
Eff 17.8
Inf
Eff 9.2
Inf
Eff 17.3
Inf
Eff 6.9
Inf
Eff 10.9
Loading
(g BODr;/m3-day)
Per Cell Accum
10.2
8.6
11.0
8.4
13.5
9.1
21.9
17.5
BOD 5
Mean
185
38
142
29
213
49
149
50
124
55
158
36
151
78
191
41
Stand
Dev.*
79
20
51
8
89
27
45
11
86-162
25-78
47
16
59
25
113
13
Number Percent Removal
Samples
97
95
34
38
40
37
21
21
6
6
16
12
14
14
12
12

79
80
77
66
56
77
48
79
                    (Continued)

-------
Table  10.  Continued
COD
Period
Second Year Overall
Series Operation
Second Year Winter
Series Operation
Second Year Surnner
Series Operation
CO
4=» Third Year Winter
Parallel Operation
Third Year summer
Single Cell Operation
Fourth Year Winter
Series Operation
Fourth Year Summer
Single Cell Operation
Fifth Year Winter
Series Operation
Station
Inf
Eff
Inf
Eff
Inf
Eff

Inf
Eff
Inf
Eff
Inf
Eff
Inf
Eff
Inf
Eff
Mean
507
149
350
113
587
195

492
214
436
314
582
190
482
443
444
192
Stand
Dev.*
208
52
103
13
236
53

148
22
337-521
237-345
193
52
212
129
201
43
Number
Samples
49
51
17
18
19
20

20
21
7
6
16
17
14
14
13
13
Percent Removal


71
_
68
_
67

.
57
.
28
.
67
_
8
_
57
Mean
237
56
149
30
292
88

198
71
197
150
226
60
196
252
141
59
Stand
Dev*
113
38
71
7
97
41

83
14
128-284
SS
Number
Samples
112
113
36
41
46
45

21
20
7
98-187 6
75
15
112
107
55
19
16
18
14
14
15
13

Percent Removal

.
76
_
80
_
70

_
64
_
24
_
73

(-29)
_
65
    The range  is shown where the number of samples collected is less than ten.

-------
          Flow diverted to 1/2 of
          lagoon for broken airline
          repair
                            L-H/2 of lagoon drained
                            I   for short period to
                            I   repair airlines

(-Changed from series ,j,F|ow diverted to 1/2 of
  to parallel operation  r   |agoon  to insta|| new
   Flow diverted to 1/2 of
   lagoon  to install new
   diffusers
   20
Back in normal
operation j
                                                                                                I
                                                                                                ^
     Changed from pa-
     rallel to series
         detention time-day

          Effluent temperatu,re-°C
                      29IU32714,42
                                                                                     \   \t    s •
                                                                                 	M"	^
                                                                         'V-^Effluent BOD-mq/J
                                                                               I  I  I  I   I
                                                               Problem with
                                                               blower 81 broken
                                                               air heater in cell 4
       S 0 N D  J  F
         1972   |
JJASCTNDJFW
 1973
MJJASONDJFM
   1974
                                            J  J AS 0 N  D  J
                                            1975          I
                FM
                1976
Figure  18.  Eagle River  lagoon  operating  results.

                                                     85

-------
A comparison of various phases of the lagoon  operation  indicates




that series operation is superior to parallel  operation  during




winter months (Table 10).  A comparison of summer  series  and




parallel operation was not possible because of  the  need  to  do




repair work during these months.






There seems to be little difference in BCD removal  efficiencies




from the second to the fifth year; however, the data  does  in-




dicate a decrease in COD and SS removals over  this  period.   This




could be attributed to a lack of adequate sludge storage  with  the




result that bottom sludge is resuspended and  carried  out  the ef-




fluent pipe .






The second year overall series operation was  selected as  a




typical full year's operation.  The effluent  parameters  for  that




year were plotted on probability paper (Figure  19).   The  plots




indicate the BOD and SS exceeded 30 mg/1 55%  and 70%  of  the  time,




respectively.  The SS exceeded 70 mg/1 30% of  the  time.






Col iforms






The effectiveness of the Eagle River disinfection  contact chamber




is shown in Table 11.  The chamber is baffled  so that the length




of liquid travel is 12.2 m.   Chlorine gas is  fed to the  lagoon




effluent stream about 20 m before it enters the chamber.






The arithmetic mean and geometric mean of the  coliform counts  are




both shown.  The chamber is  most effective at  nominal contact
                                86

-------
    200
     175
     150
 1  125
 o
 (S)
c
o>
Q_
cn
u
C/)
k_
o

Q
O
DO

c

-------
                                       Table 11.  Eagle River aerated Lagoon Disinfection  Summary
         Period

        Second Year Winter
         11/10/72-3/28/73

        Second Year Summer
         5/10/73-9/26/73

        Third Year Winter
         12/12/73-2/28/74

02      Third Year Summer
OT       7/25/74-9/6/74

        Fourth Year Winter
         11/21/74-3/25/75

        Fourth Year Summer
         6/4/75-9/4/75

        Fifth Year Winter
         12/2/75-2/25/76
Nominal Contact
Time (Min)
92
107
98
101
95
76
60
Chlorine
Residual (mg/1)
1.5
1.0
1.0
1.0
0.8
1.2
1.9
Total Coliforms
per 100 ml (Avg)*
1525 (221)
2037 (516)
922 (302)
790 (314)
6,100 (1938)
60,890 (8446)
27,800 (20,275)
Fecal Coliforms
per 100 ml (Avg)*
-
-
0.4 (1)
16.4 (9)
37.6 (12)
744 (39)
419 (139)
Numbev
of samp"
4
19
17
10
28
19
26
             Value in parentheses = geometric mean

-------
times greater than 90 minutes with fecal coliforms exhibiting




less resistance to chlorination than total coliforms.






EIELSON AIR FORCE BASE FULL SCALE LAGOON






Lagoon Description






The Eielson Air Force Base Lagoon is similar in design to the Ft.




Greely Lagoon except that aeration is provided by Kenics




Aerators.  The lagoon had two principal cells 30 m X 12 m at the




base which were egually divided into two smaller cells by a




baffle below the surface of the water.  The total lagoon volume




was 56,030 m  at an operating depth of 3 m.  A chlorine contact




chamber of 81.4 m  provided a contact time of 30 min. at




3,900 cu m/day flow.  The lagoon receives effluent from the EAFB




primary treatment plant.






Operation Problems






During startup in November, 1973, the lagoon was filled with lake




water for testing purposes.  When the aeration system began




operation, the combination of cold water and cold air resulted




in ice buildup on the aerators.  The aerators, which were con-




nected to flexible air lines, plus the small concrete pads on




which they were mounted floated to the surface.  The lagoon was




drained and the aerators returned to their original position.




The introduction of warm wastewater melted the ice and the aera-




tion system has since performed satisfactorily with no problems




(3im O'Neil, Personal Communication, 1976).



                                89

-------
The lagoon liner was brought to the top of the dike with no




gravel or rip 'rap covering.  Tearing problems from  ice movement




have not occurred in the main lagoon; however, patching of a




number of holes was necessary in the chlorine contact chamber




which was constructed in the same fashion as the main lagoon.




The holes were made by ice movement the previous winter-  Separa-




tion at the seams of the main lagoon liner did occur during the




first winter's operation and these were repaired during May and




Dune, 1974.  The liner manufacturer attributed the  separations




to waste petroleum products in the wastewater.  An  alternate




cause may have been installation of the liner without sufficient




slack to account for contraction at colder temperatures.






BDD and 5_S Removals






Operating performance of the lagoon from January, 1974 through




April 1976 is presented in Figure 20.  The results  show evidence




of aging by the lagoon as the effluent quality for  1975-76 is




generally lower than for 1974.  The highest effluent SS occurred




in June, 1974 when one-half of the lagoon was taken out of opera-




tion for repairs.  Dumping of large amounts of septic tank sludge




apparently caused a high effluent BOD in September  1974,






Because of the frequency of changes in the lagoon operation which




occurred during the study period, a good comparison of series and




parallel operation was not possible (Table 12).  The series




operation during the first summer appears to have improved the
                                90

-------
  30


  20


  10


   0

 240'


 200


 160


 120


  80


  40


   0
                     -Changed from Parallel
                      to Series  Operation
                          I    /
                                Detention Time-days
                                                       Changed from  Parallel to
                                                     ^""Series Operation /•-
 Lagoon No 1
-Drained for  —
_Repairs to
 Liner
-May 23-June 16
                               Received-20,000  Gal
                               Septic Tunk  Sludge
                               within One  Week Period
— Changed  from  Series to     _f
  Parallel Operation
              A
                                  Influent BOD-mg//
                                            A
                    /Influent ss-mg//

                                /Effluent BOD-mg//
             Effluent ss-
                  II
I   I   I
       Jan   Mar    May    July   Sept  Nov
         I            1974
                                        Jan   Mar   May    July   Sept   Nov    Jan   Mar
                                         !              1975                    I  1976
Figure 20.  EAFB full scale  lagoon  operating results.

-------
                                               Table 12.  Performance Summary of EAFB Full  Scale Lagoon*
i-D
ro
Period
First Winter
Parallel Operation
First Summer
Parallel Operation
First Summer
Series Operation
Second and Third Uinter
Parallel Operation
Second Summer
Series Operation
Second Summer
Parallel Operation
First Uinter
Parallel Operation
First Summer
Parallel Operation
First Summer
Series Operation
Second and Third Winter
Parallel Operation
Second Summer
Series Operation
Second Summer
Parallel Operation
Detention
Time (Days)
Station
Inf
Eff 17.8
Inf
Eff 20.9
Inf
Eff 19.5
Inf
Eff 22.8
Inf
Eff 22.1
Inf
Eff 31.0
Inf
Eff
Inf
Eff
Inf
Eff
Inf
Eff
Inf
Eff
Inf
Eff
Loading
(q BOD ^/m^ -day)
Mean
136
7.8 35
137
6.6 30
137
7.0 22
158
6.9 52
139
6.3 79
133
4.3 55

80
37
81
31
84
21
74
41
64
36
73
43

Stand
Dev.t
31
15
124-155
13-49
77-175
11-30
48
13
109-223
10-163
14
15

15
10
71-97
19-44
72-61
10-61
28
8
57-79
19-52
15
8
BODS

Number Percent Removal
Samples
11
11
5
5
8
8
30
30
6
6
10
10
SS
11
11
5
5
9
9
30
30
6
6
10
10

74
78
84
67
43
59

54
62
75
45
41
43
               *     No  COD's  reported.

               t     The range is  shown  where the  number of samples collected is  less than ten.

-------
treatment efficiency.  The poor second summer series  operation




may have been caused by septic tank sludge as evidenced by  the




high BOD levels compared t.o the SS levels.  The  septic tank




sludge was not accounted for in the influent parameter values.






Col iforms






Performance of the chlorination contact chamber  was somewhat er-




ratic with the poorest performance occurring in  June  and  July,




1975 (Table 13).  The greatest concentration of  algae may have




been produced at that time, however, the lowest  rate  of chlorine




feed also occurred during that period.  In the original design




of the chamber, the chlorine feed line entered the pond next to




the chamber influent line.  The chlorine feed was modified  during




the spring of 1975 to enter the waste stream at  the effluent col-




lection man hole which allows mixing in 6 m of pipe before  en-




tering the contact chamber.  This modification has improved  the




chlorination effectiveness as evidenced by the winter parallel




data .






PALMER AERATED LAGOON AND POLISHING POND






Lagoon Descr iption






The original Palmer waste treatment system, which drained into




a facultative lagoon, was replaced in the summer of 1972  with  an




aerated lagoon which also discharged to the facultative lagoon.




The aerated lagoon and the polishing pond were of earthen dike
                                93

-------
                                 Table  13.  EAFB Full Scale Lagoon Disinfection  Summary


                                   Nominal             Chlorine            Chlorine            Fecal               No. of
  Period                      Contact Time (Min)      Feed (mg/1)         Residual  (mg/1)    Coliforms/100 ml*'      Samples

Winter Parallel
   11/19/74-02/11/75                 37                   -                   0.7              1,994  (98)             6
   11/04/75-02/24/76                 42                  6.6                   0.6             17,260  (92)            16

Summer Series
   06/03/75-07/08/75                 37                  4.4                   0.3               0-TNCt               8

Summer Parallel
   09/05/75-10/07/75                 53                  7.6                   0.4                111  (29)            10
*    Values in parantheses = geometric mean.

t    Included 3 values of 0 and 4 TNC (too numerous to count).

-------
construction with a side slope ratio of 3:1 and  sealed  with  ben-



tonite.  Common dimensions of the aerated lagoon  were



30 m X 220 m.  The aerated lagoon volume was  24,600 m   at  an



operating depth of 2.7 m.  Aeration was provided  by perforated



tubing diffusers.  The polishing pond area and volume were


        2             3
17,846 m  and 27,250 m  respectively at an operating depth of



1.5m.
Operation Problems





The lagoon began operation in October,  1972 and  has  suffered  from



relatively few operating problems, apparently due  to  the  rela-



tively light loading on the lagoon, the overall  design  and  the



excellent maintenance provided.   Sludge which had  accumulated  in



the polishing pond before installation  of  the aerated lagoon  oc-



casionally would rise to the surface after operation  began.   The



rising sludge did not create a nuisance and has  not  been  observed



since the first year of operation.





Destruction of the aeration pattern by  bottom sludge  settling



near the influent line occurred  in the  aerated lagoon and  the



system was drained for repair during the summer,  1975.   About



0.6 m of sludge was found around  the inlet pipe.   The depth



tapered to a few centimeters at  a distance of 6  m  from  the  inlet



pipe.  After the sludge had dried, a backhoe was  used for  removal



and the tubing replaced in that  area.   An  additional  aeration



device was placed near the influent line for the  purpose  of
                                95

-------
resuspending the bottom sludge so that recurrence of the problem




may be prevented.  The effectiveness of the new device has not




been determined.






BOD and ^S Removals






Operating results are presented in Table 14 and Figure 21.   The




data was supplied by the City of Palmer.  Samples were collected




3 times per week by the city operators and pH, DO and tempera-




tures recorded and 55 determined.  BOD analyses were made once




per week.  BOD, DO and 55 analyses were performed with Hach  Kits.






Polishing pond effluent dissolved oxygen levels have been in-




cluded in the graph as an indication of the polishing pond ef-




fects.  As may be expected,  the DO levels were high in the summer




due to algae action and low  in the winter.  The winter DO




measurements consistently leveled off at 2 mg/liter.  DO levels




from the aerated ].agoon average about 8 mg/liter in the winter




which apparently maintain the 2 mg/liter level in the polishing




pond e ffluent.






The overall system has provided consistently good treatment  with




little difference in winter  and summer periods.






Aerated lagoon effluent data was collected from July 2 through




September 12, 1973, a period during which the polishing pond was




not in operation.  The data  indicated that the aerated lagoon by




itself attained 55?o BOD removal.  When compared with 91% BOD
                               96

-------
                                  Table 14.   Performance Summary of Palmer  Lagoon*

Det. Loading/day

Operation Station Time g/BODs/m-Yday Mean
Aerated Lagoon Only
07/02/73-9/12/73
Winter - Aerated Lagoon
plus Facultative Lagoon
01/07/74-04/01/74
12/04/74-03/28/75
12/01/75-03/31/76
Summer - Aerated Lagoon
plus Facultative Lagoon
05/17/74-07/17/74
08/09/74-09/09/74
Overall - Aerated Lagoon
plus Facultative Lagoon
.Inf 51.6
Eff 3.5
Inf 106.0
Eff 1.8



Inf 102.7
Eff 2.0


Inf 109.6
Eff 1.7
182
42
192
16



209
6


188
11
BODs
Std Devt
125-270
15-110
83
14



60
4


74
12
SS
# Samples
8
9
43
41



13
13


47
45
% Rem Mean
128
77 58
184
92 17



181
97 18


185
94 17
St. Dev
64
38
61
4



59
11


56
7
# Samples
32
28
141
141



41
41


156
147
% Rem
.
55
_
91



.
90


_
91
05/01/74-04/30/75

   No COD's reported.
   Range of values given for No of samples less than 10.

-------
OO
                             -Facultative lagoon under
                              repair-Aerated lagoon
                              treatment only
                               Facultative pond out of
                               operation for repairs 7/19-8/8
                                                                -Aerated lagoon drained for
                                                                 repairs-No samples taken
                                                             110 days mean detention time
                                                                                                 	1 20.
                                                                 \ fdetention tme-days
                           Effluent dissolved oxygen-
                                            ^Effluent temperature-°C
                                                              .^Influent BOD-mg/J
Influent SS-mq
                               Effluent SS-mq/J
                                  Effluent BOD-mg//
                                                             f-30 mq/J
                                                                                                         en
                                                                                                         £
                                                                                                        O
                                                                                                        a
                                                                                                         CL
               AMJJASONDJ
                      1973
                   AMJJASONDJFMAMJJASONDJFM
                        1974             I           1975              I   1976
     Figure  21.   Palmer lagoon operating results.

-------
removal for the aerated lagoon-polishing pond combination,  one




can infer that a significant amount of treatment  is  taking  place




in the polishing pond.






The period from May 1, 1974 to April 30, 1975 was selected  as a




typical full year's operation and plotted on probability paper




(Figure 22).  The effluent BOD and SS exceeded 30 mg/1  10%  and




4% of the time respectively.  The effluent SS exceeded  70 mg/1




less than 1% of the time.









A major portion of treatment in the polishing pond  is similar to




the treatment which occurs in the aerated cells,  i.e.,  settleable




solids deposit under quiescent conditions and the settled sludge




undergoes anaerobic decomposition.  Assimilation  and oxidation




of organic matter and oxidation of biological solids occur  at a




very reduced rate because concentrations have been  reduced  by




treatment in the aerated cells.






During summer months, algae removal occurs through  sedimentation




and subsequent anaerobic decomposition and through  consumption




by higher organisms.  These various phases of treatment are




discussed in Section 7.






STUDIES BY OTHERS






To arrive at a more comprehensive picture of cold climate aerated




lagoon performance BOD and SS data on lagoons outside Alaska  were
                                 99

-------
      50
      40
   CD
  •O
   C
   CD
   Q.
   in
  Q
  O
  QQ
   c
   CD
   ZJ
  Ld
      30
      20
      10
       0
i    i    i  i   r
    Suspended
    Solids
i    i    r .  i
         1   2   5  10   20   40  60    80  90 95  98
                        Time Less Than  (%)
Figure 22.  Palmer lagoon  effluent BOD and suspended solids variability.
                              TOO

-------
incorporated in our analysis.  These lagoons are in Eagan Town-




ship, Winsted and Redwood Falls, Minnesota (Breinhurst, 1970);




three lagoons near Winnepeg, Manitoba (Penman et al.,  1970) and




a lagoon at Harvey, N. Dakota (Vennes, 1970).






The BOD and 55 removals obtained with these lagoons is summarized




in Tables 15 through 17.  Fecal and total coliform  results for




the Harvey, N. Dakota lagoon are also presented in  Table 18.
                                101

-------
                                            Table 15.   Performance  Summary of Minnesota Lagoons*
o
ro


Lagoon
Eagan, Minn
2nd & 3rd years


3rd Winter


2nd & 3rd Summer



Eagan, Minn
2nd & 3rd years


3rd Winter


2nd & 3rd summer




Station

Inf
Cell -1
-2
Inf
Cell -1
-2
Inf
Cell -1
-2


Inf
Cell -1
-2
Inf
Cell -1
-2
Inf
Cell -1
-2
Detention Loading
Time (Days) (g BODs/m3-day)
Per Cell Accum. Per Cell Accum. Mean

1225
7.0 7.0 175.0 175.0 225
8.4 15.4 26.8 79.6 113
1107
9.2 9.2 120.3 120.3 257
9.9 19.1 26.0 58.0 159
1324
5.5 5.5 240.7 240.7 178
6.8 12.2 26.2 108.5 116


764
823,
31 Ol
372
413
148
1069
1009
538

Stand
Dev.

880-1750
60
73
960-1255
222-290
44-218
880-1750
118-230
78


264-2110
302
180
273-446
300-545
33-220
330-1880
790-1220
529

Number
Samples

10
12
21
3
3
5
6
6
10


10
11
21
3
3
5
5
5
10
BODj.
Percent
Per Cell

-
83
50
_
77
38
_
87
35
SS

-
17
62
—
0
64
.
6
47

Removal
Accum

-
83
91
_
77
86
_
87
91


-
17
69
.
0
60
_
6
50
                    (Continued)

-------
Table 15.   Continued
Detention
Time (Days)
Laqoon Station
Redwood, Minn
2nd Year Inf
Cell -1
-2
-3
2nd Winter Inf
Cell -1
-2
-3
o 2nd & 3rd Summer Inf
00 Cell -1
-2
-3
Winsted, Minn
2nd & 3rd Year Inf
Cell -3
3rd Winter Inf
Cell -3
2nd & 3rd Summer Inf
Cell -3
Per Cell

_
14.1
31.6
42.0
_
18.0
37.0
44.0
.
12.1
28.1
33.8

-
-
_
-
_
-
Accum.


14
45
87

18
55
99

12
40
74


74

68

74

_
.1
.7
.7
_
.0
.0
.0
.
.1
.2
.0

.
.0
_
.0
.
.0
(p
Per

_
12.
1.
0.
_
9.
1.
0.
.
12.
1.
1.

-
-
_
-
_
~
Loading
BOD5/m3-day)
Cell


0
2
8

3
4
3

9
3
0







Accum.

_
12.0
3.7
1.9
_
9.3
3.0
1.7
.
12.9
3.9
2.1

-
12.6
_
12.6
„
14.3
BOD 5

Mean

169,.
39*
32
15
167
51
15
9
156.
36f
34T
19

930t
62
857
75
loeol
57
Stand Number
Dev. Samples

38
11
17
7
170-215
50-52
10-23
8-11
100-225
26-165
13-68
6-33

450
42
540-1290
30-112
290-1990
7-125

12
11
12
20
3
2
3
5
6
6
6
9

12
19
3
5
6
9
Percent
Per Cell

_
77
18
54
_
70
71
40
.
77
8
44

-
-
_
-
_
~
Removal
Accum

_
77
81
91
_
70
91
95
_
77
79
88

-
93
_
91
_
95
          (Continued)

-------
Table  15.  Continued.
Lagoon Station
Redwood, Minn
2nd Year Inf
Cell -1
-2
-3
2nd Winter Inf
Cell -1
-2
-3
2nd & 3rd Summer Inf
Cell -1
-2
-3
Wins ted, Minn
2nd & 3rd Years Inf
Cell -3
3rd Winter Inf
Cell -3
2nd & 3rd Summer Inf
Cell -3

Mean

202
95
60
42
258
58
21
20
187
134
85
64

479
77
318
106
619
64

Stand
Dev.

41
50
32
27
215-334
48-68
16-25
14-38
146-232
86-172
59-110
25-107

197
55
243-358
46-170
340-835
7-150

Number
Samples

12
10
12
19
3
2
3
5
6
5
6
8

12
19
3
5
6
9
SS
Percent
Per Cell

-
53
37
30
_
78
63
7
_
28
36
26

-
-
_
-
_
—

Removal
Accum

-
53
70
79
_
78
92
92
_
28
54
66

-
84
_
67
_
90
*    No COD's reported.
f    Range of values reported for number of samples  less  than  10.
T    Adjusted from probability plot.

-------
                                        Table 16.  Performance summary of Winnepeg lagoons.1
o
en
Operation
First & Second
Years Overall
(21 months)


First and Second
Winter



First Year
Summer



Series Operation
Jan, Feb, Mar,
1972




Station
Influent
Effluent
Air Aqua
Surface Aerator
Air Gun Aerator
Influent
Effluent
Air Aqua
Surface Aerator
Air Gun
Influent
Effluent
Air Aqua
Surface Aerator
Air Gun
Influent
Effluent
No 1 Secondary
Air Gun
Surface Aerator
Air Aqua 1
Air Aqua 2
Detention
Time


30
20
20
_

30
20
20
_

30
20
20
„

-
6.2
12.4
17.1
21.8
Loading
g BOD/m3-day


5.8
8.8
8.8
_

6.9
10.3
10.3
_

4.4
6.7
6.7
_

-
20.0
10.0
7.3
5.7
BOD
Mean
175

37
38
34
206

41
47
39
133

21
19
15
223

124
82
57
44
36
5
I Removal


79
78
81
_

80
77
81
_

85
86
89
_

-
34
54
65
71
SS
Mean
188

34
39
34
199

42
56
45
157

32
31
32
263

41
56
91
51
32
% Removal


82
79
82
_

79
72
77
_

80
80
80
_

-
(-37)
(-122)
(-24)
22
      * No COD's reported.

-------
                                   Table  17.  Performance summary of Harvey, N. Dak. Aerated Lagoon.*
o
01


Period
1 st through 4th years


Winter 1st, 2nd and
4th years
Jan through Mar
Winter 3rd year
Jan through Mar

Summer 1st through
4th years
June through Sept

1st through 4th years


Winter 1st, 2nd and
4th years
Jan through Mar
Winter 3rd year
Jan through Mar

Summer 1st through
4th years
June through Sept
* No COD's reported.
t The range is shown where
1 Calculated from the data
Detention Loading
Time (Days) (g BODs/m3-day)
Station Per Cell Accum. Per Cell Accum.
Inf - - - -
Cell -1 20 20 13.2 13.2
-2 20 40 6.3 6.6
Inf - - - -
Cell -1 20 20 15.6 15.6
-2 20 40 6.5 7.8
Inf - - - -
Cell -1 20 20 33.3 33.3
-2 20 40 11.3 16.6
Inf - - - -
Cell -1 20 20 14.0 14.0
-2 20 40 4.7 7.0

Inf
Cell -1
Cell -2
Inf
Cell -1
-2
Inf
Cell -1
-2
Inf
Cell -1
-2

the number of samples is less than 10.
reported.


Mean
263
126
53
312
129
50
665
226
160
280
93
28

166
118
67
221 :
111-
72^
190:
187-
124-
185^
117-
71-




Stand
Dev.
134
76
45
180
10
23
950
65
19
117
28
23

118
74
39
: 152-316
58-172
32-104
; 100-322
• 100-524
90-160
: 114-312
40
: 37




Number
Samples
.
-
-
_
-
-
_
-
-
_
-
-

_
-
-
7
8
8
6
6
6
7
13
13



BOD5
Percent
Per Cell

52
58
_
59
61
_
66
29
_
67
70
VSS
.
29
43
_
50
35
_
2
34
_
37
39




Removal
Accum
.
52
80
_
59
84
..
66
76
_
67
90

.
29
60
_
50
67
_
2
35
_
37
61




-------
                     Table 18.  Harvey, N.  Dak Aerated Lagoon  Fecal  and  Total  Coliform  Results
o
-xl
Jan-Mar (66,67,69)
   % Removal

Jan-Mar (68)
   % Removal

June - Sept (All)
   % Removal
Feed

1.1 x 106


7.4 x 106


1.3 x. 107
Fecal  Coliforms

     Cell  1

    6.0 x  105
       45

    2.5 x  106
       66

    1.3 x  106
       90
 Cell 2

7.9 x 104
   93

1.0 x 106
   86

1.0 x 10"
   99.92
              Jan-Mar (66,67,69)
                 % Removal

              Jan-Mar (68)
                 % Removal

              June - Sept (All)
                 % Removal
                              6.9 x  106


                              6.8 x  107


                              6.9 x  107
               Total  Coliforms

                   1.8  x  106
                     74

                   7.3  x  106
                     89

                   4.2  x  106
                     94
                       4.8 x  105
                          93

                       5.4 x  106
                          92

                       7.0 x  101*
                          99.90

-------
                        SHORT-CIRCUITING


Short-circuiting is one of the most important problems with

lagoons, with wind playing a major role (Barsom, 1973).  Dye

studies were conducted on the Ft. Greely lagoon in order to gain

an idea of the degree of short-circuiting taking place for that

particular lagoon design.


The dye studies were conducted over 24 hour periods.  Observa-

tions were recorded in terms of relative concentrations because

dye adsorption and decay could be expected to invalidate absolute

results .


The first test was made on the coarse bubble diffuser side but

had to be abandoned because of very high winds which developed.

Some information was gathered, however.  One hundred fifty ml of

Rhodamine B dye was added at the splitter manhole.  Evidence of

dye was seen at the first two inlets of the influent header after

2 minutes.  The dye then began to drift toward the center baffle

near the dike with some mixing with the aerator cluster.  The dye
                                                       *
continued to mix with the aeration cluster but also drifted over

the center baffle.  Visible evidence of the dye was seen over

halfway into the 2nd cell along the dike.  Short circuiting was

obviously taking place with the high winds making a major con-

tribution to the problem.
                                108

-------
Additional dye studies were conducted at a later date under




calmer wind conditions.  The patterns of visible dye movement ob-




served are shown in Figure 23.  Again the wind, although very




light, had a major effect on the apparent short-circuiting which




was taking place.  Times required for the dye to reach the ef-




fluent are shown in Figures 24 and 25.  The readings were taken




with a Turner fluorometer and are plotted as relative concentra-




tions.  In this case 750 ml of Rhodamine B dye were added to both




the coarse bubble and fine bubble diffuser sides of the lagoon.




The peak concentrations of dye reached the far end of the coarse




bubble side in about 3.5 hours and the effluent at 4 hours.  The




relative concentration at the effluent dropped from 28 at 4 hours




to about 7 at 7.5 hours and then began a gradual climb and




leveled off around 22 at 21 hours.  The effluent peak at 4 hours




for the coarse bubble lagoon was obviously due to short cir-




cuiting.  The gradual increase from the low at 7.5 hours to the




leveling off at 20 hours and greater was due to dye which entered




the aeration pattern.  This type of curve is more likely to occur




under complete mix conditions without short circuiting.  On this




basis the dye concentration peak for the far end occurred at




about 3 hours due to the high level of mixing in the first cell.




The peak for the effluent did not occur until after 20 hours




because of the low mixing level occurring in the second cell.






A similar action occurred in the fine bubble side of the lagoon.




The dye concentration peaked at 31 at 4.5 hours on the far end
                               109

-------
       Fine  Bubble  Diffuser side
                                           Wind
                                           <5mpt
Coarse  Bubble  Diffuser side
                    Perforated Tubing
                        Diffusers

            \S 2 hrs.
            \       Baffle  Approx. T
            J       Below Water  Surface
            1                  ^~i
            1         1C
            I
                                                         L
   Bottom Outline
    Diffuser  Cluster
Figure 23.   Visual observation of dye injection in the Ft. Greely lagoon.

-------
    35
    30  -
    25  -
  c
  o
  P 20  -
  c
  o>
  o
  c
  O  


  1  10
  cr
      5  -
                                               Hours
Figure  24.  Dye injection results,  Ft. Greely coarse  bubble aerated lagoon.

-------
      35
      30
   .1  25
   0
   t-

   "c
      20
   £   15
   _o
   CD



       10
Cell  1
         0
        10
15
20
25
                                             Hours
Figure  25.  Dye injection  results, Ft.  Greely fine bubble  aerated lagoon,

-------
of the lagoon.  Heavy concentrations were visible near  the dike




at the far end at less than two hours and a sample taken at  this




point read off the scale on the fluorometer.  Samples at the far




end of both lagoons were normally taken off the end of  the dock.




The curves for the fine bubble side are somewhat more erratic due




to the channeling of the dye around the aeration pattern in  the




first cell (Figure 23).  It is not known  if channeling  occurred




in the second cell since the dye became less visible at this




point.  The effluent peak occurred around 8.5 hours, which was




about 4 hours later than for the coarse bubble side, and dropped




to around 15 before -climbing back to about 21 at 20 hours.
                                113

-------
               FT. GREELY OXYGEN TRANSFER STUDIES






METHODS AND PROCEDURES






In order to compare the performance of the coarse and fine bubble




aerators, oxygen transfer studies were conducted at the Ft.




Greely lagoon.  DO uptake values were determined through the use




of a bottom sludge respirometer constructed at the AERS




laboratory and with light and dark BOD bottle uptake measure-




ments.






Three docks were placed on each half of the lagoon as shown in




Figure 6 to facilitate sampling.  DO levels in the lagoon were




determined with a YSI meter (Model 54) and probe (Model 5418).




DO's were measured at various points throughout the lagoon at the




beginning of the sampling season and found to be reasonably




uniform or within approximately 1 mg/1 throughout each half of




the lagoon.  Thereafter, DO's were determined at mid-depth from




the three docks on each half of the lagoon and the DO levels




reported are an average of these.






DO uptakes were determined by bringing samples into a laboratory




building and shaking the samples for aeration.  The samples were




then placed in BOD bottles in a water bath at the same tempera-
                               114

-------
ture  as the lagoon and the DO's read with the YSI meter




(Model 54) and YSI BOD probe  (Model 5420).  This procedure  was




accomplished within a few minutes.  The bottles were agitated and




the DO levels read periodically during the uptake period.   Uptake




rates were determined from curves obtained by plotting DO levels




versus time.






Uptake rates obtained during  periods of algae growth were deter-




mined by the use of light and dark BOD bottles as described by




Camp (1963).  Samples were collected at two depths  in the lagoon,




1 foot and 7 foot levels, and placed in four BOD bottles, two of




which were painted black to prevent light penetration.   Initial




DO levels were determined in  each bottle and these  were  hung  in




the lagoon at the respective  sample depths.  The bottles were




then removed periodically in  alternate pairs and the DO  levels




de term ined .






The bottom sludge respirometer consisted of an 8 inch diameter




plastic tube open at the bottom and with a flat cover on the  top.




Mounted on the top were a YSI model DO probe and a  small sub-




mersible pump supplied by The Little Giant Pump Co., Oklahoma




City, Oklahoma.  A large surface area flange was placed  around




the bottom to prevent the respirometer from sinking  into the




sludge.  The bottom of the respirometer was extended 2 inches




with a piece of sheet metal to ensure a good seal at the sludge




face .
                                115

-------
The submersible pump and probe were mounted  so  the  pump




discharged over the DO probe eliminating  any  stagnation.   The




discharge was restricted so that the flow  was very  gentle  and  a




minimum of stirring occurred in the respirometer.






When using the respirometer, a plug was removed  from  the  top  and




the respiormeter submerged.  All of the trapped  air was  allowed




to escape and the plug replaced.  The unit  was  then lowered  into




place and the submersible pump started.   Periodic  DO  readings




were taken over periods which ranged from  1  to  4  hours.






The true uptake rate of the bottom sludge  was determined  by  sub-




tracting the lagoon liquid  uptake rate determined  in  the  BOD




bottles from the rate established in the  respirometer .






Values of 0.85 and 0.90 were used for a and  g respectively,  for




all calculations.  These values were obtained through laboratory




tests conducted in a 10-liter cylindrical  shaped  container.




Lagoon effluent was brought to the laboratory,  held overnight,




and two runs made with effluent and two runs  with  tap water  on




the same day, in accordance with the procedure  outlined  by Ecken




felder and Ford (1970).  Gentle aeration  was  provided with a




glass tube of 3 mm diameter.  A value for  g  was  obtained  by




aerating the container contents for an extended  period  and com-




paring the saturation value obtained with  the standard  value  for




the corresponding temperature and pressure.   A  6  value  of  1.02




was used for temperature correction of the  K. a  values obtained
                                116

-------
in these studies.  C  was calculated for mid-depth in accordance
                    s                          r


with methods discussed earlier.






RESULTS






Table 19 presents the oxygen transfer data collected and is




grouped by type of aerator.  Also shown is one data point for the




Northway lagoon which at that time had Air Gun aerators.  The




last data point is taken from the literature and represents an




evaluation of an Air Gun installation at Brampton, Ontario (Thon,




1964).  The data include the effect of surface aeration.






Horsepower requirements were calculated based on the following




formula (Fair et al., 1971):






     hp = 0.227 Q (  (P2/P1)°'283 - 1)



                Q = Air flow in SCFM (14.7 psia and 70°F)




                P- = Discharge pressure of blower  (psia)




                P, = Atmospheric pressure (psia)




              1 hp = 0.746 kW






An overall efficiency loss of 30 percent was assumed for the




blower and motor for all calculations.  Actual blower discharge




pressures were used for the Ft. Greely fine bubble and  Northway




Air Gun calculations, while 125 percent of the submergence depth,


             2

or 0.35 kg/cm  was used for the coarse bubble diffusers.  This


                                     2

assumes a pressure loss of 0.02 kg/cm  through the main  header




since the pressure measured at the point of the coarse  bubble air
                               117

-------
                                                 Table  19.  .Oxygen  Transfer Summary
CO
Aerator

Ft. Greely
Coarse
Bubble



Ft. Greely
Fine Bubble
Northway
Air Gun
Brampton
Air Gun
(Thon, 1964)
Date
Feb
Apr
Apr
May
Nov
Dec
Feb
Apr
Apr

May



18
6
28
18
30
22
18
6
28

23



Liquid
Temp
°C
<0.5
<0.5
5.2
10.5
1.0
1.0
<0.5
<0.5
5.2

8.0


14.8
Ice
Cover
%
90
40
0
0
30
70
100
50
0

0


0
D.O.
Level
mg/1
6.9
9.1
5.2
7.0
3.8
0.7
9.1
3.2
1.0

5.0


3.6
D.O.
Uptake
mg/l/hr
0.34
0.23
0.30
0.46
0.42
0.34
0.21
0.17
0.18

0.37


0.43
Air Supply
I/sec -
1000 m3
9.0
12.7
11.7
13.5
12.2
8.7
8.7
4.5
4.3

21.5


17.2
02 Transfe
Efficiency
%
3.8
1.9
2.7
3.7
3.5
4.0
2.5
4.1
4.4

1.7


2.6
;r KLa
' Calcu-
lated
0.064
0.054
0.049
0.142
0.049
0.030
0.047
0.019
0.019

0.070


0.064
(hr-1)
Adjusted
to 20°C
0.094
0.079
0.066
0.170
0.071
0.044
0.069
0.028
0.025

0.088


0.073
kg 02/
KW-hr
0.86
0.44
0.64
0.92
0.82
0.96
0.33
0.65
0.60

0.43


0.44

-------
                                                             2
lines tied into the main header was approximately 0.33 kg/cm  .


The Brampton A'ir Gun data point was calculated by the author  of


that paper using the submergence depth of the aerators, about  a


20 percent inherent efficiency loss for compression and a  35  per-


cent efficiency loss for the aeration system  (Thon, 1964).



Mixing over the center baffle was too great to permit separate


evaluation of the two types of coarse bubble  diffusers at  Ft.


Greely.  As a result, the diffussr performances have been  lumped


together for evaluation.  This should not detract substantially


from the results as any difference between the two coarse  bubble


aerators will be small compared to that between the coarse bubble


and fine bubble aerators.



The progressive drop in DO levels for the fine bubble diffuser


shown in Table 19 is a result of the clogging mentioned


previously.  Data for the fine bubble aerator were not obtained


on May 18 because the lagoon had gone anaerobic at that time-


Oxygen transfer data for November and December were not obtained


because the repunching of the tubing which occurred during the


summer changed the fine bubble diffuser characteristics.   The


higher DO uptake values reported for the coarse bubble diffusers


were a result of higher influent flows to that side.
Figure 26 presents a plot of the K. a value at  20°C  times  the


aeration basin volume per diffuser (K. a x V) versus  the air


rate per diffuser (1.0 SCFM = 0.47 liters/sec).   The coarse
                               119

-------
20000
10000
9000
8000
7000
6000
5000
4000


3000



2000
KLa-V

1000
900
800
700
600
500
400

300


200




100
	 1 	 1 	 1 	 1 	 1 1 1 1 | 1 1

-
-
: T
-
0
™~ f

T/ T
"~~ ^
s
/ f 1
/ 9
/
1 	 \ 	 1 1 1 1
- —
T ~

/'--
/
*
—







/
/ D
— >/^ —
— ^r ~
JT O ~_

— —
— —
_ -
A
— — — Shear f user - From Eckenf elder —
— — — Extension of Eckenf elder Curve
O Ft. Greely Coarse Bubble Diff.
A Ft. Greely Fine Bubble Diff.** _
O Northway Air Gun
D Brampton Air Gun *
A
A * * Values / IOO ft of tubing
\ 1 1 1 1 1 1 1 1 | | I 1 1 1 1
                          4   5  6 7 8 9 10        20
                             Gs- SCFM/Diffuser
30  40  50 60   80  100
Figure  26.  Air flow rate vs.  KLa  •  V  for aerated lagoons.

                                   120

-------
bubble diffusers were evaluated as Shearfusers.   This was  done




because, situated in the first cell where the oxygen demand  was




greatest, the Shearfuser clusters received the major portion  of




the total air flow (approximately 80 percent).  Each Aer-0-Flo




diffuser cluster was considered as on Shearfuser  diffuser  (based




on air flow) which made a total of 10 Shearfusers for calculation




purposes.






The solid line shown was obtained from the literature and  relates




the K. a value for a certain diffuser and  tank configuration  to the




tank  volume per diffuser (Eckenfelder and O'Connor,  1961).   The




curve is based on data obtained in a tank 7.3 m long by  1.2  m




wide  by 4.6 m deep, using the  Shearfuser  diffusers.  Other curves




for similar coarse bubble diffusers were  shown in the reference




but are not presented here.






Because of  the variability of  the Shearfuser data obtained at  Ft.




Greely, maximum and minimum values of K. a based on  possible  er-




rors  in procedures and equipment were calculated  and a range  of




K. a values  were plotted as shown.  The accuracies used in  the




calculations were as follows:






      C = -0.5 mg/1 - Standard  Methods indicates an




         accuracy of -0.1; however, -0.5  was used because




         of the slow instrument response  to  the cold




         conditions during the studies.
                               121

-------
     r = -15 percent - Sawyer and McCarty  (1967)  indicates




         the BOD test accuracy is considered  to be  5  percent.




         The 15 percent value was used to  account  for  sampling




         error .




      3 = -0.05




      a = io.10






The uppermost point shown represents the data for  May  18  which




is probably the most questionable because  of  the  need  to  account




for algal DO production and bottom sludge  demand.   The  algal  DO




production and bottom sludge demand values were varied  by  +50




percent and -50 percent respectively for the  error  calculations.






It should be noted that the somewhat lower efficiencies exhibited




by the Air Gun diffusers on Figure 26 may  not be  truly  represen-




tative.  The Northway lagoon had a liguid  depth of  2.3  m  which




was less than would normally be provided in a lagoon  designed  for




Air Gun aerators.  Also, bottom sludge demand or  algae  DO  produc-




tion was apparently not accounted for in the  Brampton  study  and




may have been significant factors at the liquid temperature




re por ted .






OXYGEN BUDGET






The oxygen uptake rates obtained for the Ft.  Greely coarse  bubble




lagoon are presented to show the relationship of  oxygen demand




at various times of the year to the average BOD loading on  the
                                122

-------
lagoon (Table 20).  As may be expected the oxygen demand in-




creased a great deal during the summer months with a good portion




of the increase compensated for by algal production.  It appears




from the data presented that a ratio of 1.5 g 0?/g BOD^ removed




can be used for sizing aeration equipment for cold climate




aerated lagoons.
                                123

-------
                             Table 20.  Ft. Greely Coarse Bubble Lagoon Oxyqen Budget
ro
Date
02/18/72
04/06/72
04/28/72
05/18/72
06/15/721
11/30/72
12/22/72
Mixed Liqour Uptake
kg 02/day
119
83
107
213
446
148
120
Sludge Uptake* Alqae Production Aeration Requirements
kg 02/day kg 02/day kg 02/day
119
83
107
9 59 163
39 155 330
148
120
Ratiot
BOD5 BOD5
Removed Applied
1.5
1.0
1.3
2.0
4.0
1.8
1.5
1.1
0.8
1.0
1.5
3.'
1.4
1.1
            Sludge uptake rates found during the winter were less than 2 kg/day and considered negligible.

            Ratio = (kg 02/day aeration requirement)/(Average BOD5 applied or removed/day).  The average BOD5
            applied or removed per day was 106 kg and 82 kg respectively.

            The data for 6/1^/72 is considered unreliable because of the very high oxygen transfer rates
            found for the aerators.  The sludge uptake rate for that date does appear reasonable.

-------
                           DISCUSSION









BOD AND SS REMOVAL






Year-round BOD percentage removals were plotted  in  Figure  27  and




curves representing plug flow and complete mix conditions  were




applied to the data by least squares methods.  The  complete mix




curve having the form






                        E = (A+Kt/1+Kt) 100




                  where E = Percent BOD removed




                        A = Initial fraction of  BOD  removed




                        K = Reaction rate coefficient  (I/day)






appears to most nearly represent the data.   'A'  is  the  fraction




of BOD removed within the first few hours or days  through




sedimentation and bio-oxidation.  The equation was  obtained by




performing a material balance on the lagoon  process  (Eckenfelder ,




1970) and adding a term for sedimentation.   The  values  obtained:




                       A=0.56 and K=0.058




are very similar to values reported by Reid  (1970)  of  0.55 for




the initial removal and 0.063 for the reaction coefficient using




a similar approach.
                               125

-------
         100
CTl
                                   40          60          80
                                      Detention Time  (Days)  = T
100
    Figure 27.  Year-round percent BOD removals  vs.  detention  times,

-------
The same equation was applied to the year-round suspended  solids




data and values of 0.30 and 0.058 were obtained for A and  K




respectively (Figure 28).






These equations were also applied to the winter and summer data




(Figures 29 and 30).  'A1 values were assumed to be constant  at




0.56 and 0.30 in order to obtain a comparison of the reaction




rates as follows:




                         BOD Removal           SS Removal




                       A            K        A           K




Year-round           0.56         0.058    0.30      0.058




Winter               0.56         0.055    0.30      0.048




Summer               0.56         0.066    0.30      0.044






A comparison of the plots for BOD removal and for the remaining




SS shows more scatter in the SS data, particularly for the summer




periods.  The EAFB experimental lagoon data has been identified




in these figures to provide a comparison of data from a number




of cells in series with the overall data.  In all cases the 6




cell operation provided the best performance; however, much of




this data was obtained during the first 18 months of the lagoon




operation before the aging effect was fully realized.  The number




of cells in series seemed to have the most pronounced effect  on




summer SS removals when compared to the overall data.  This may




be the result of a change in algae species which will be




discussed later.  The data also indicates that BOD removals are
                               127

-------
ro
oo
0
                   10     20    30     40    50    60    70     80    90    100    110

                                        Detention Time (Days)
    Figure  28.  Year-round percent  suspended solids  remaining vs. detention  time.

-------
    100



    90
  "S80
    70



  §60
50



40





80



70
  ^60
  c
  "o

  I 50
  en

  on

  -1 40
  o
  CO


  "S 30
  0>
  CO
     10
     0
                                EAFB Experimental Aerated Lagoon

                                     A  6 cells in series

                                     o  4 cells in series

                                     •  Other Lagoons
       0    10   20   30
                        40   50   60   70   80
                         Detention Time-days
90    100  110
Figure 29.  Winter percent BOD removal  and percent suspended solids remaining
vs.  detention time.
                                 129

-------
    100
    80
   
   "g
   "o

   I

   I40
   ~o
   CO
   CD

   £20
   CL
   to
   CO
      0
                I
            I
I
                                                  I
       0
20
40        60        80
  Detention Time-days
               100
120
Figure 30.   Summer percent BOD removals and percent suspended  solids  remaining
vs.  detention  time.
                                    130

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improved in the summer although the SS remaining  is  increased  and




much more variable because of algae growth.






SOLUBLE BOD REMOVAL






A small fraction of BOD residual does not  appear  to  be  removed,




even after long detention periods  (Eckenfelder and O'Connor,




1961).  This has been attributed to an equilibrium between  BOD




removed and the release back to solution of respiration  and  auto-




oxidation end products.  A plot of soluble  (filtered  through




45 micron filter paper) BOD values shows this residual  to be




about 10 mg/liter for aerated lagoons with  detention  times  less




than 40 days (Figure 31).  Reduction of the soluble  BOD  to




10 mg/liters can occur within 20 days detention time  even under




extreme winter conditions.  After  this time, removals of BOD oc-




cur through auto-oxidation and sedimentation of solids.






Soluble BOD data was obtained from the EAFB Experimental Lagoon




and the Ft. Greely Lagoon under winter conditions and from  the




Ft. Greely Lagoon under summer conditions.  Soluble  BOD  informa-




tion was also obtained from a report by Girling et al . ,  (1973)




on four aeration basins operated in series.  The  values  shown  at




zero detention time represent the  influent  to the lagoon.   In  the




case of the Winnepeg lagoons, the  raw waste was fed  to  a primary




cell where the soluble BOD increased before entering  the aerated




cells.
                               131

-------
   120
   100
    80
  CD
 jl


 a 60
 o
 CD
 ~o
 C/)
    40
    20
     0
                                   o   Winnepeg Aerated  Lagoons

                                   A   EAFB  Experimental  Lagoon

                                       Ft,  Greely Aerated  Lagoon
             0
10           20
Detention  Time  (Days)
30
40
Figure  31.  Soluble BOD  vs. detention time.
                                   132

-------
REACTION RATES






Reaction rates are dependent on substrate concentrations and, in




lagoon systems, will consequently be dependent on detention




times.  For a single cell lagoon, increasing the detention time




will decrease the overall reaction rate because of the increased




substrate dilution.  Increases in lagoon detention times result




in lesser increases in BOD removal efficiencies (Thirumur-




thi, 1974).  This is an important consideration in determining




the removal efficiencies of lagoon cells operated in series using




the relationship 1/(1+KT)  since the value of K will decrease




with each succeeding cell in series.






After initial oxidation occurs in a biological waste treatment




process, the cellular constituents are progressively more dif-




ficult to oxidize and the rate declines in a logarithmic manner




(Eckenfelder and O'Connor, 1961).






The year-round BOD and SS removal rate coefficients (K) were




determined for each cell of the lagoons under consideration and




plotted vs loading on log-log paper (Figures 32 and 33).  The




curves were determined by least squares method.  Figures 34




through 37 show plots of winter and summer BOD and 55 removal




rate coefficients.






A slight curve in the data, particularly for the summer data, ap-




pears to exist in the log-log plot.  The smaller summer K values
                               133

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GO
-p.
      g 0.005

     ^ 0.003
        0.002
        0.001
            0.1   0.2  ,0.4     1.0  2.0 4.0     10   20   40    100

                              Loading (g BOD/1000m-day)
400
    Figure 32.  Overall BOD removal  rate coefficient vs.  loading.

-------
CO
en
      1.0


      0.6

      0.4


      0.2

 i
-£     0.1
a;

«   0.06
      o
      o
      o
      cr

    0.04


    0.02


     0.01


   0.005

   OO03

   0.002


   0.001
                                                        i—i—i i i i 1
                                                            Correl.  Coef.   i
                                                               0.79

                                               = 0.018La72     0.73

                                                  Negative k values
                                                   not used
                    I   i  I  I I I I I I	,1  I  I  I I  I I I I	I   I  I fS\ I I II I 7g> I   I
             0.1    0.2  0.4     1.0  2.0  4.0     10   20   40    100


                               Loading (g BOD/1000m-day)

    Figure 33.  Overall suspended solids removal rate coefficient  vs.  loading.
                                                                  400

-------
CO
            1.0
           0.6
           0.4

           0.2

            0.1
      
-------
GO
                                             = 0.014 LQ83
                                           k = 0.011 L°'94
              1   0.2  0.4    1.0  2.0  4.0     10  20  40    100     400
                              Loading (g BOD/1000m-day)
    Figure 35.  Summer  BOD removal rate coefficient vs. loading.

-------
GO
00
      1.0


      0.6

      0.4



      0.2
*:
 i
^    0.1
0>

£  0.06

«  0.04
o
o

£  0.02
o
cr

       rr
   0.003

   0.002
                                      k = 0.034L0-44

                                      k= 0.(
Correl. Coef.  1

     0.53

     0.59
                                                           Negative k values
                                                            not used
          0.001
               0.1
                     i   i  i  i i i l i
                                                      i   i  fl^ i i i
             0.2«  0.4    1.0  2.0  4.0     10   20   40    100     400


                         Loading (g BOD/1000m3-day)
    Figure  36.  Winter suspended solids removal rate coefficient vs. loading.

-------
OJ
     1.0 r

    0.5
    0.3
    0.2
*:
I    0.1

g   .05
•*—
s* \
    .03
    .02
       o
       O
       cr
       c
       o
     .01
       o  .005
       a>
          .002
          .001
                                        i  ~\  i i i i i I	1	1—i—i I i i 1
                                                .   * *
                                      k = 0.0141_°-63
                                             k = 0.009 Lv
                                                       0.88
Correl. Coef.
   0.59
   0.60
      0.1   0.2   0.4    1.0  2.0   4.0    10   20   40     100
                        Loading (g BOD/1000m -day)
                                                                          400
     Figure 37.  Summer suspended solids removal rate coefficient vs. loading.

-------
at the lower loadings are assumed to be caused by algal growth.




The apparent non-linear relationship has been accounted for by




fitting two curves for each set of data points, one for lower




loadings and one for higher loadings.  Some of the data points




were not used in determining the curves.  These points are in-




dicated on the figures.  The curves indicate a relatively rapid




increase in removal rates with increasing loading at the lower




loadings.  This condition makes it more difficult to apply the




data to lagoons at the lower loadings, as will be seen in the




sample calculations section.






SLUDGE ACCUMULATION






The need for adequate sludge storage in aerated lagoons is made




particularly clear by the Eagle River Lagoon experience where ef




fluent quality deterioration was obviously caused by sludge car-




ryover.  Lower aerated lagoon performances after the first year




of operation are also apparently caused by sludge accumulation.




These  factors point out the need for incorporating sludge ac-




cumulations into aerated lagoon designs.






Following are average sludge analyses for the Northway and Ft.




Greely lagoons:
                                140

-------
                  Total




                  % Solids     % Volatiles       pH      COD(mg/g)




Northway




     Cell 1           12            50          7.1          88




     Cell 2           20            29          7.6          46






Ft. Greely




     Cell 1           21            42          5.9




     Cell 2           52             7




The Northway sludge exhibited the characteristics of well




digested sludge.  The pH was relatively high and the sludge had




a black appearance and a musty odor.  These conditions indicate




significant methane fermentation and loss in the form of methane




of relatively large amounts of oxygen demand from the system.  On




the other hand, the Ft. Greely sludge exhibited a low pH and




brown, odorous characteristics which indicate production of




volatile acids which were not transformed to methane but diffused




into the liquid and exerted an oxygen demand.  The Ft. Greely




sludge pH levels were lower than those reported by Oswald  (1968)




as optimum for methane formation but near optimum for organic




acid formation.  pH levels for the Northway sludge were generally




in the optimum range for methane formation.  It is possible that




the poor sludge digestion of the Ft. Greely lagoon occurred




because the solids were deposited immediately upon entering the




lagoon, probably in a septic condition, so that optimum condi-
                                141

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tions for organic acid formation were present and perpetuated




from the beginning.  The lagoon began operation in late fall when




the low temperatures would also preclude the growth of methane




formers.  Oswald (1960) has stated that lagoon bottom sludge can




exhibit characteristics of a stuck digester (i.e., high pH  which




retards methane fermentation) and that overcoming this condition




is quite difficult.  It follows that startup of lagoons should




occur during the warmer summer months or sludge seed containing




methane formers, such as from a sludge digester, should be  added.




Also, if the entering solids are maintained in suspension for a




period, undergo some degree of aerobic oxidation and are




deposited under the higher pH conditions existing in the lagoon




mixed liquor, conditions more conducive to methane formation may



be maintained.






The sludge analyses for the Ft. Greely and Northway lagoons are




somewhat variable but indicate that decomposition of the sludge




occurs year around.  Rubel and Gray (1965) also reported




% Volatiles of  approximately 50  for sludge samples taken in




January and February and Duly and September.  This is in agree-




ment with values reported by other investigators.






Very little information is available on rates of sludge accumula-




tion.   Sludge volumes obtained from the Northway and Ft. Greely




lagoons and information reported by Penman et al., (1970) are



shown in  Table 21.
                              142

-------
       Table 21.  Sludge Accumulation  Summary  (8,/lDOO  m  )
                         Cell 1           Cell  2           Total






Northway                   935              465             1400




Ft. Greely                 620              145              765




Winnepeg




  Air Aqua                1720              380             2100




  Air Gun                 1880                             1880
At Winnepeg the high volumes of  sludge may  be explained  by  the




fact that the information was obtained during the  first  eighteen




months of operation.  The Northway  and Ft.  Greely  lagoons were




somewhat older when conditions closer to equilibrium  existed.




This follows from Fair's estimate that it takes  over  five years




to stabilize stream sludge deposits.  Using  Northway  as  the  most




typical situation,  it is suggested  that  for  sludge  accumulation




calculations a value of 1500 liters/1000 m   of domestic  sewage




be used .
                                143

-------
ALGAE





The major algae blooms in subarctic lagoons occur around the



month of June and are reduced significantly after the sludge



turnover, which generally occurred in early July in the lagoons



observed.  This is illustrated by the Ft. Greely lagoon ex-



perience.  Major algae growth appears to begin after approx-



imately ten days detention time and follows a typical growth



curve as shown by the EAFB experimental aerated lagoon ex-



perience .





The 1971 experience with the EAFB experimental aerated lagoon



generally agree with statements by Gloyna (1968).  Chlorella were



dominant during the major algae bloom of June and early July when



high sludge decomposition rates and the growth of high energy or-



ganisms resulted in presumably high loading.  After the sludge



turnover and the corresponding reduction in the lagoon loading,



Daphnia and filamentous algae became dominant with reduced levels



of unicellular organisms resulting in reduced effluent SS levels.



A suitable environment for zooplankton growth, as suggested by



Dinges (1975), was apparently present.





The correlation of loading and algae blooms is also born out by



the Palmer lagoon experience.  Summer loading on the total lagoon



was 2 g BOD/m -day with resultant BOD and SS levels of 6 and



18 mg/liter respectively.  Assuming a 55% removal in the aerated



cell as for July through September, 1973, the loading on the


                                3                   ?
facultative pond was 1.7 g BOD/m -day or 5.1 g BOD/m -day.




                                144

-------
The advantage of operation with a number of cells  in  series  is




illustrated by a comparison of the EAFB experimental  lagoon  and




Ft. Greely lagoon data.  The peak chlorophyll values  and  cor-




responding SS values obtained were as follows:






                                 Chlorophyll  (m-
EAFB Experimental Lagoon                   780               86






Ft. Greely Lagoon                          1100              141






The higher Ft. Greely values are attributed  to  the  lower  number




of cells in series.  A greater diffusion of  incoming  raw  waste




occurred because of the complete mix conditions  and  the high




degree of short-circuiting in that  lagoon.   The  result  is  a




higher level of bacterial activity  throughout  the  lagoon  and  a




correspondingly greater algae growth apparently  because of  the




carbon dioxide generated.






NUTRIENTS






The nutrient data results indicate  little  change  in  NH-.-N  or  T-N




levels during winter operations and removals of  N H -, - N  ranging




from 25 to 48% in the summer.  T-N  removals  were  less,  indicating




a transformation of inorganic Nitrogen  to  the  organic  form  by  al-




gae .






Ortho-phosphates and total phosphorus  levels  increased  in  almost




all cases which would indicate the  net  annual  removals  to  be
                                145

-------
zero, assuming the analytical results were accurate.   The




phosphorus apparently had previously accumulated in the bottom




sludge and was being released to the lagoon liquid.






These results are apparently typical of lagoons operated  under




cold climate conditions.






COLIFORMS






The coliform removal data from the EAFB experimental lagoon  and




the Harvey, N. Dakota lagoon followed expected patterns (Figure




38).  Die off rates were  greater during summer periods.   Also,




for a given detention period, the more cells in series the




greater the die off rate.  The latter experience is in agreement




with results reported by  other investigators (Slanetz  et  al . ,




1970).  The EAFB experimental lagoon achieved 99.98% removal




during winter operation with 6 cells in series and during summer




operation with 4 cells in series.






The effectiveness of disinfection chambers at the EAFB full  scale




lagoon and the Eagle River lagoon are shown in Figure  39.   At-




tempts to correlate coliform counts with the product of contact




time and chlorine residual were not successful and better results




were obtained plotting coliform levels vs contact time.   The  data




from the Eagle River and  EAFB lagoons indicate little  difference




in disinfection effectiveness during winter and summer opera-




tions.  This would seem to indicate the summer algae production
                               146

-------
   100
  o100
  o
  £
  
-------
     200
          1     A
       50
     o
     o
      
-------
results in disinfection rates similar to those during cold  tem-




perature operations in winter.






The fecal coliform data also supports the contention that




monitoring chlorine residual as a means of determining disinfec-




tion effectiveness will not be satisfactory.  The EAFB lagoon ef-




fluent coliforms were reduced at lower contact times and lower




chlorine residuals than the Eagle River Lagoon effluent




coliforms .






AERATION SYSTEMS






Although fine bubble diffusers have performed successfully  in




aerated lagoons for a number of years, clogging  is obviously an




inherent characteristic in their operation.  The clogging can




cause maintenance problems, particularly in small installations




where the operator may have many other duties to attend to  aside




from operation of the waste treatment system.  Some problems




which have occurred include blower damage, breaks in plastic




piping, blowing out of the ceramic diffusers, etc.  Many problems




have also occurred with the plastic pipe in the  Eagle River




lagoon which were not associated with high system pressure.






In most cases, cleaning of fine bubble diffusers is required with




greater frequency than recommended by the manufacturer.  Per-




forated tubing cleaning is generally required monthly to maintain




desired blower discharge pressures.  Cleaning of the porous
                                149

-------
ceramic diffusers may be required once per year, based on  the


limited information available.



Obstruction of the fine bubble aerators may occur internally


during shutdown of the blowers which allows wastewater and


suspended matter to enter the aeration system through the  dif-


fusers and leaks in the piping.  Clogging can occur  through ob-


struction by particulate matter or through an inability to force


water out of the system through the diffusers.  Removal of the


material from the tubing may be accomplished by installation of


bleed lines and "rocking" the system as at the Palmer Lagoon.


Particulate matter in the air supply will also cause internal


clogging although this has not been a problem at most sites in


Alaska .



External restrictions can be caused by calcium carbonate deposits


from hard water or organic slime growths over the diffusers.


Clogging of the perforated tubing, which is designed to lie on


the lagoon bottom, may also* occur from sludge deposits on  top of


the tubing.  Clogging of the porous ceramic diffusers can  occur


during blower shutdowns due to lint and hair collecting on the


diffusers and in the pores.



Routine cleaning of both types of fine bubble diffusers is


generally accomplished with hydrochloric acid fed to the aeration


system and forced through the diffusers at approximately

         2
1.4 kg/cm  or by applying hydrogen chloride gas to the system
                               150

-------
while the blowers are in operation.   The latter method  requires




the greatest care because of the toxic and corrosive nature  of




the material.  Amounts of material used  for cleaning have  varied




considerably.  In the case of perforated tubing, quantities  of




3.7 and 1.6 g/m of hydrochloric acid  and hydrogen chloride gas,




respectively, appear to be adequate if a monthly cleaning




schedule is adhered to.  Sufficient information was not  available




on the porous diffusers to determine  the amount of cleaning




material required.






In a number of cases, more extreme cleaning methods have been




necessary.  These have included draining the lagoon to  a level




which would permit access to the diffusers and hand cleaning with




the blowers in operation.






Air Gun aerators have also been utilized in lagoons for  a  number




of years.  The main operating problem has been blocking  by rags,




and whether this problem has been corrected is not known.






AERATION DIFFUSERS






Information has been presented  which  indicates the coarse  bubble




diffusers can provide an attractive alternative for aeration in




lagoons, particularly in smaller systems.  The K.a values  ob-




tained from the Ft. Greely coarse bubble diffuser  studies  cor-




relate well with those obtained for the  same diffuser  in a large




scale activated sludge aeration tank  model.  The  data  shows  that
                                151

-------
coarse bubble aeration systems for lagoons can be designed  based




on oxygenation efficiencies published in the literature  or  sup-




plied by diffuser manufacturers.  The oxygenation efficiencies




should be obtained from large scale test tanks rather  than  small




columns, however, for reasonable accuracy.  The data also  in-




dicates the K. a value can be predicted for coarse bubble dif-




fusers in lagoons using the equation developed by Eckenfelder and




information presented in the literature (Eckenfelder and




O'Connor, 1961; Eckenfelder and Ford, 1968).






Studies have shown that increased aeration tank widths decrease




oxygenation efficiencies to a certain minimum level but  that




spreading the diffusers out over the tank bottom increases  oxy-




genation efficiencies.  The large width to depth ratio of  lagoons




will decrease diffuser efficiencies to some extent, probably 2




to 3 percent efficiency for coarse bubble diffusers based  on




studies mentioned previously (Bewtra and Nicholas, 1964).   Ef-




ficiencies for a given diffuser can be maximized, however,  by




adequate spacing to minimize interfering bubble patterns.






Although the fine bubble diffusers1  oxygenation efficiencies are




greater, the diffusers are not necessarily more economical.  The




data presented in Table 19 indicates approximately 0.79-0.84 kg




transferred/kWh for the coarse bubble diffusers, as opposed  to




approximately 0.6 kg 0  transferred/kWh for the fine bubble  dif-




fusers under generally clogged conditions.  Assuming for the Ft.
                               152

-------
Greely lagoon that 190 1/s at 0.35 kg/sq cm would be required  for




a coarse bubble diffuser system while 142 1/s at an average  of




0.46 kg/sq cm would be required for a fine bubble diffuser system




under normal conditions, the increased cost for the coarse bubble




system would be $78/year greater at 2 cents/kWh.  However, if




cleaning were required monthly for the fine bubble diffus-ers,  as-




suming 4 man hours per cleaning at $10/hour and $8 material  cost,




maintenance cost would be $576/year or a net  $498/year greater




cost for the fine bubble diffuser system.  These differences will




increase if hand cleaning is necessary and decrease if higher




power costs exist.  Based on the above, it appears that operation




and maintenance costs for fine bubble diffusers may be equal to




or greater than the costs for coarse bubble diffusers if sig-




nificant clogging occurs.






One aspect of aeration system design which must be considered  in




some areas is ice fog generation.  Visual observations at Ft.




Greely indicated open water over all four coarse bubble diffuser




clusters throughout the winter period.  These open areas




decreased in size as the air temperature decreased and would al-




most completely ice over above the Aer-0-Flo  clusters at -40°C.




The open area above the Shearfuser cluster near the influent al-




ways remained larger, shrinking to about 7.5  m  in diameter at




-40°C.  Significant ice fog generation seemed to occur only  over




this cluster.   Ice fog blankets were not observed around the




lagoon as the ice fog formed was either not enough  to become a
                                153

-------
nuisance or dissipated rapidly.  It should be noted that the in-




fluent sewage temperatures to this lagoon range around 20°C even




in winter and that lower influent temperatures would reduce ice




fog generation.   During the colder period of the year, the per-




forated tubing side of the lagoon was completely ice covered and




no ice fog was observed.






Although no attempts at heat balance calculations have been made,




an observation is that greater heat losses occur over diffusers




with larger air  flows or greater turbulence because of the larger




open areas maintained.  This greater heat loss through the open




area is compensated for by increased ice thickness, or lesser




heat losses, through the rest of the lagoon.  Thus, a fine bubble




diffuser lagoon  may have a thin ice cover over the total surface




while a coarse bubble lagoon may have thicker ice over less than




100 percent of the lagoon due to greater concentration of air




flows.  Where ice fog may be a problem or extensive freezing is




anticipated, diffusers should be selected which require less air




flow per diffuser and will permit greater dispersion of the air




pattern.  Smaller clusters of diffusers should also be used.  As




indicated previously, oxygenation efficiencies will not be sig-




nificantly affected as transfer rates are independent of diffuser



spacing .
                               154

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                    LAGOON  DESIGN AND UPGRADING






DISCUSSION






A comparison of data  from  the  Eagle  River and Palmer lagoons  il-




lustrates the importance  of  proper design.  Second year overall




series operation data  from  the  Eagle River lagoon and data for




the period May 1,  1974  through  April 30, 1975  for the Palmer




lagoon were plotted on  probability paper.  The percentage of  BOD




and 55 analyses that  exceeded  30 mg/1 and 70 mg/1 were as fol-




lows:






                                                   Loading




     Lagoon   3j3 m_g_ BOD    3>TJ  m_g_ S_S   7_0 m_g_ S_S   c[ BOD/m--day




     Eagle R.      55          70         30        10.2




     Palmer        10           4         <1         1.7






The Eagle River lagoon  performance,  although poor, is the more




typical of present  subarctic  lagoons.  The lagoon is overloaded,




has inadequate sludge  storage  and has been plagued with aeration




system problems which  have  contributed to the poor performance




results.  The Palmer  lagoon,  on the  other hand, while not an




ideal design, has  a considerable reserve capacity.   Some  problems




have been encountered  with  the  fine  bubble aeration  system.
                                155

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These problems have been minimized by close  attention  to  the




lagoon and some innovative maintenance provisions  such  as  instal-




lation of bleed off piping at the ends of  the main  air  headers




to blow water out of the tubing diffusers.






In the design or upgrading of cold climate lagoon  systems,  the




following objectives should be kept in mind:






1.  As in any biological treatment system, conversion  of dis-




solved and colloidal organic material into suspended solids  which




can be removed by sedimentation is essential.  Soluble  BOD  can




be reduced to around 10 mg/1 in relatively short periods




(<20 days) even at 0°C liquid temperatures.






2 .  A high proportion (25-50 ?o) of the first  cell aeration  should




be concentrated at the lagoon influent to  prevent  buildup  of




sludge under septic conditions.






3.  Adequate sludge storage must be provided in the first  sec-




tions of the lagoon so thaf adequate treatment of  the  organic




acids etc.,  given off during summer fermentation,  occurs before




the effluent is discharged.  Accumulation  of approximately  1500




liters of sludge per 1000 m  of influent should be  allowed  for.






4.  Lagoon cells should be provided in series to rsducs short-




circuiting due to complete mix conditions  and other causes.   For




lagoons of a given detention time, the numbers of  bacteria  and




indicator organisms are reduced further in multicell series




systems than in single cell lagoons.





                               156

-------
5.   A polishing or maturation pond should be  provided  as  the  last




cell in series to allow sedimentation of any  settleable solids




and consumption of unicellular algae by higher  organisms.   Care




should be taken to provide an optimum environment  for  zooplankton




growth.  Loading on the polishing pond should be limited  to 1 -




1.5 g BOD/m3-day or 4 - 5 g BOD/m2-day.






A suggested lagoon arrangement is shown in  Figure  40 and  sample




design calculations follow.  A short detention  cell is created




at  the influent structure by constructing a baffle.  Heavy  aera-




tion in this cell will keep more solids in  suspension  and allow




greater aerobic oxidation before the solids are deposited.  Also,




the soluble BOD will undergo greater reduction  with higher  VSS




levels .






Sludge storage is provided over the total bottom area  of  the




aerated cells in order to avoid excessively deep sludge deposits.




Colder sludge temperatures can be expected  with deeper deposits




which will result in reduced decomposition  rates.  The aerators




are shown elevated and also in a configuration  which will allow




sludge removal.






Placing of the aerators in a straight line  parallel to the  flow




and along the full width of the lagoon will also aid in reducing




short-circuiting.  A rolling motion of the  fluid will  be




established in the section between each line  of aerators  which




will promote mixing of incoming waste in that section  before  the
                                157

-------
                          Baffle-
                                           Diffuser
                              Cell     1
                                         9'-12'Typical
                                              o
                              Cell     2

                                    V
                              Cell    3
                      6 i7
                        V
                              Cell     4
                                              Rubble
Figure  40.  Suggested lagoon arrangement.

                                    158

-------
waste moves to the next section.   The  aeration  pattern  will  tend




to create a barrier to complete mixing  throughout  the  pond  and




thereby reduce short-circuiting.   Short-circuiting  can  be  further




reduced by the strategic placement  of  baffles  which, do  not  extend




to the pond surface but which  serve  as  an  additional barrier  to




complete mix conditions.






A polishing pond  is provided  to permit  sedimentation of any




remaining settleable solids during  winter  operation  and to




provide for algae reduction during  summer  operation.   The  pond




should provide a  suitable environment  for  macro-organisms  such




as Daphn ia which  prey on the  algae.   If  aeration  is  provided  it




must be gentle and not promote excessive agitation.  Adeguate




dilution must be  provided to  reduce  organic  concentrations  and




to curb algae blooms which raise  pH.   Rubble may  be  included  in




order to provide  a surface for the  growth  of the  macro-organisms.






Some precautions  regarding freezing  must be  considered  when  using




a lagoon arrangement as suggested  in  Figure  40.   In  the design




of multi-cell systems, special care  must be  taken  to avoid




freezing problems when transferring  from one cell  to another.




The application of adeguate insulation  and/or  the  addition  of




heat (heat tapes  e.g.) at the  transfer  points  are  necessary in




Arctic and Subarctic areas (Lynn  Wallace,  personal communication,




1976).  Also, if  the baffles  are  designed  to extend into the




freezing zone, special baffle  designs  must be  provided to  prevent




ice damage.







                                159

-------
Possible alternatives to the above scheme  include  long  term



storage with discharge once or twice per year  at appropriate



receiving water conditions (Pierce, 1974); phase isolation  as



practiced in California (Hiatt, 1975); and discharge  to  natural



lakes or swampland as described by Grainge et  al.,  (1972).





All of the above considerations should be  examined  in the design



of new lagoons or upgraded lagoons.





SAMPLE CALCULATIONS





It has been shown that the reaction coefficient in  the complete



mix equation is related to loading by the  following equation (See



Figures 32 and 33):





(1)        K = aLb



   where   K = reaction coefficient



           L = loading (g BOD/m3-day)



         a&b = constants



Also :



(2)        L = S /t
                o


   where  SQ = influent BOD (mg/1)



           t = detention time (days)



By substitution into  the complete  mix  equation it can be shown



that :
                               160

-------
 3)
           t =
               a .  S
Using Figures 32 through 37 and the above relationships, the per
formance of a lagoon may be predicted.

As an example, winter BOD removals have been predicted for a
lagoon as follows:
   Assumptions :
     S  (Influent BOD) = 250 mg/1
      o
     S  (Effluent BOD) =  20 mg/1
      e                       ^
    55  (Influent Suspended Solids) = 200 mg/1
    55  (Effluent Suspended Solids) =  20 mg/1 (winter)
    55  (Effluent Suspended Solids) =  60 mg/1 (summer)
         Cell 1 DT
         Cell 2 DT
         Cell 3 DT
         Cell 4 DT
         Cell 1
10 days
15 days
15 days
v
              L = S /T = 250/10 = 25
                   o
              From Figure 34, K = 0.15
              5=5 /(I + Kt) = 250/(1 +  0.15  X  10)  =  100  mg/1
               e    o
                                161

-------
         Cell 2



              L = 100/15 = 6.7



              From Figure 34, K = 0.08



              S  = 100/(1 + 0.08 X 15)  =  45.5  mg/1
               e




         Cell 2



              L = 45.5/15 = 3.0



              From Figure 34, K = 0.056
              S  = 45.5/(l + 0.056 X 15)
               e
         Cell 4



              Using equation (3)




              t =
                       = 24.7
24.7/20 - 1
                              ,0.49
                  l/U-0.49)
                  0.033 X 24.7



                             1.96

              t = (0.24/0.16)

              t = 2 . 2 days
Total detention time required = 42 days.   Using  the  same  approach



for summer BOD removals, the performance would be  as follows:



         Cell 1_



               L = 250/10 = 25



               From Figure 35, K = .20



               S  = 250/(1 + 0.20 X  10) =  83.3
                                162

-------
         Cell 2



              L = 83-3/15 = 5.6



              From Figure 35, K = 0.056



              S  = 83-37(1 + 0.056 X 15) = 45.3
         Cell
L = 45.3/15 = 3.0



From Figure 35, K = 0.030



S  = 45.3/(l + 0.030 X 15)
                                         = 31.2
         Cell 4
              Using Equation (3


                   31.2/20 -1
              t =
                 0.94

     0.011 X 31.2




     (0.56/0.28)16'7
                                    = unrealistically high
Because of the rapid decline of the K values at low loadings, the



last cell size is unrealistically high.  Try 5 cells in series:






         Cells 1-4    DT = 10 days




         Cell !_



              L = 250/10 = 25



              K = 0.20



              S  =83.3
               e


         Cell 2




              L = 83.3/10 = 8.3
                                163

-------
              K  =  0.08
              S   =  83.3/U  +  0-08  X  10)  =  46.3
              e
         Cell  3_


              L =  46/10  =  4.6



              K =  0.046


              S  = 46/(l  + 0.05  X  10)  =  31.5
               e



         Cell  4


              L =  31.5/10  =3.2



              K =  0.033
S  = 31.5/Cl + 0.033 X 10)
 e
                                         = 23.7
         Cell  5
              Using  Equation (3 )


                   23.7/20 - 1
              t =
                               0.94
                   0.011  X 23.7
                   (.018/0.22)16'7 =0.05
Again, because of the rapid decline in K values at lower


loadings, the last cell size obtained with equation (3) is not


realistic.  The calculations do indicate that 5 cells total with

                                                        •
the first 4 cells sized at 10 days detention time each will be


adequate.  The last cell should be sized using the loading factor


of 1.5g BOD/m -day-
                               164

-------
              t = SQ/1.5  r 23.7/1.5  =  16  days



              Total detention  time  =  56  days





Using the 5 cells in series,  the  winter  BOD  removals  would  be  as



follows using Figure 34:





         Cell 1_



              L = 250/10  = 25



              From  Figure 34,  K  = 0.15



              S  =  250/U +  0.15  X  10) =  100
               cJ




         Cell 2



              L = 100/10  = 10



              K = 0.10



              S  =  100/(1 +  0. 10  X  10) = 50
               e




         Cell 3_



              L = 50/10  = 5



              K = 0.07



              S  r  50/(1  + 0.07  X 10) = 29.4
               e





         Cell _4



              L = 29.4/10 =  2.9   '



              K = 0.055



               S   =  29.4/U + 0.055 X  10) = 19.0
                                165

-------
         Cell 5_



              L = 19.0/16 =1.2



              K = 0.036



              5  = 19.0/(1 + 0.036 X 16) = 12
               e




Summer suspended solids removals are estimated  as  follows  using



Figure 37 :





         Cell 1



              L = 200/10 = 20



              K = 0.095



              S  = 200/(1 + 0.095 X 10) = 102.6
               e




         Cell 2



              L = 102.6/10 =10.3



              K = 0.063



              S  = 102.6/U + 0.063 X 10) = 62.9
               C




         Cell 2.



              L = 62.9/10 =r 6.3



              K = 0.046



              S  = 62.9/(l + 0.046 X 10) = 43.1
               tJ




         Cell 4.



              L = 43.1/10 = 4.3



              K = 0.033




              S  = 43.1/Cl + 0.033 X 10) = 32.4
                               166

-------
         Cell 5_



              L = 3.2



              K = 0.025



              5  = 32.4/(l + 0.025 X 16) = 23.14






Winter suspended solids removals using  Figure 36 would be  as  fol



lows :




         Cell 1



              L = 200/10  = 20



              K = 0.12



              Sp r 200/(1 + 0.12 X 10)  = 90.9




         Cell _2



              L = 90,9/10 = 9.1



              K - 0*065



              S  = 90.9/(1 + 0.065 X 10) = 55.1
               e




         Cell ^


              L = 55. 1/10 = 5.5



              K = 0.044



              S  r 55.1/Cl + 0.044 X 10) = 38.3
               e




         Cell 4



              L = 38.3/10 = 3.8



              K = 0.032
                                167

-------
         Cell
              S  = 38 .3/(l + 0.032 X 10) = 29.0
               e
              L = 29.0/16 = 1.8



              K = 0.018



              S  = 29.0/(1 + 0.018 X 16) = 22.5
               e
Since the effluent suspended solids are above  20 mg/1,  use  equa-



tion  (3) to recalculate the cell 5 detention time  requirement.



Using equation (3)
              t =
                   29.0/20 - 1
                               0.78
                   0.012 X 29.0
                              4.55

              t =   (0.45/0.17)



                =   83.9 days





Again, the detention time for cell 5  is unrealistical1y  high.   In



order to obtain winter suspended solids levels  of  20  mg/1  or

                           *

less, an additional short detention time  cell  should  be  added  or



the size of some of the first four cells  should  be  increased.





The advantage of using a number of cells  in series  is shown  in



Figure 41.  The winter BOD removal efficiency  of  the  5  cell



lagoon derived above is compared to the BOD removal efficiency



of a 3 cell lagoon  determined in the  same manner.   The  5 cell



lagoon with shorter detention times in the first  cells  obviously
                                168

-------
   100
    90
    80
 O


I  70

Q
O
CO
    60
O
i_
o>
Q_
    50
               10
                                           Cells  in series
20       30       40      50
    Detention  Time (Days)
60       70
  Figure 41.  Effect of cells in series on detention time.


                                  169

-------
will result in more efficient treatment.  A lagoon designed by




the procedures outlined above can be expected to meet




30 mg/1 BOD5 and 30 mg/1 SS standards in the effluent over 90%




of the time.  This conclusion is based in part on the performance




of the Palmer lagoon (see Figure 22).






The use of a very short detention time per cell (one day for ex-




ample) will result in higher loadings and correspondingly higher




removals when predicting performance from Figures 32 through 37.




This approach is not recommended, however.  Unrealistically high




removal predictions may be  the  result.
                               170

-------
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     in Northern Climates.  In:  International  Symposium  on  Water
     Pollution  Control in Cold Climates.  University of  Alaska,
     College, Alaska, 1970.  pp. 286-311.

Vesilind, P. A.  Treatment and Disposal of Wastewater  Sludges.
     Ann Arbor  Science Publishers, Inc., Ann  Arbor,  Michigan,
     1975.  236 pp.

White, G. C.  Handbook of Chlorination.  Van  Nostrand  Reinhold
     Co . , New York , 1972.  744 pp.
                                175

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                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
1. REPORT NO.

   EPA-6nn/3-7q-nn3
                                                           3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE

    Performance of Aerated Lagoons  in  Northern Climates
             5. REPORT DATE
              January 1979
             6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)

    C.D.  Christiansen and H.J. Coutts
                                                           8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS

    Arctic Environmental Research Station
    U.S.  Environmental Protection Agency
    College, Alaska  99701
             10. PROGRAM ELEMENT NO.

                1AA602
             11. CONTRACT/GRANT NO.
 12. SPONSORING AGENCY NAME AND ADDRESS
    Corvallis Environmental Research  Laboratory
    Office of Research and Development
    U.S. Environmental Protection Agency
    Corvallis, Oregon  97330
              13. TYPE OF REPORT AND PERIOD COVERED
                in-house   final
             14. SPONSORING AGENCY CODE
                 EPA/600/02
 15. SUPPLEMENTARY NOTES
 16. ABSTRACT
  Studies of cold climate aerated  lagoons  conducted by the Arctic  Environmental Research
  Station, Fairbanks, Alaska are reported.   Conclusions are based  on  these studies,
  observations of full scale aerated  lagoons operating in Alaska and  reports on lagoons
  in the northern tier of the United  States  and Canada.

  Biological processes which occur  in facultative aerated lagoons  are reviewed and the
  performance of cold climate aerated lagoons is examined.  Winter and summer performance
  is compared, and general criteria for  the  design of cold climate lagoons is presented.
  Sample calculations for predicting  the performance of aerated lagoons are also shown.
  These calculations are based on the complete mix equation for aerated lagoon design
  and on the results of the data analysis  presented in this report.   The information
  presented indicates that lagoons  can be  designed or  upgraded to meet P.L. 92-500
  secondary standards.  This may be done by  increasing the number  of  cells in series,
  by reducing short circuiting and  through the use of a polishing  pond.   It is shown
  that additional  cells in series,  for a given detention time, will  increase the BOD
  removal  efficiency of a lagoon.
                               KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
                                              b.IDENTIFIERS/OPEN ENDED TERMS
                                                                         c. COSATI Field/Group
  aerated  lagoons
  cold  climate
 i. DISTRIBUTION STATEMENT


  Release  unlimited
19. SECURITY CLASS (This Report I
    unclassified
21. NO. OF PAGES

  188
20. SECURITY CLASS (This page)

    unclassified	
22. PRICE
EPA Form 2220-1 (Rev. 4-77)
                                            176
                                                                                 •frGPO 697-484

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