Collected Papers Regarding Nitrates In Agricultural Wastewaters

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                   Collected Papers

                  Regarding Nitrates
                           In
              Agricultural Waste Waters
                     Compiled By

                         The

        Federal Water Quality Administration
760 Market Street,  San Francisco, California  94102
                         The

        United  States Bureau of Reclamation
  2800 Cottage  Way,  Sacramento, California  95825
                       and The

      California Department of Water Resources
  1416 Ninth  Street, Sacramento, California  95814

              Environmental Protection Agency
              Library, Region V
              1 North Wacker Drive
              Chicago, Illinois  60606

                Project No. 13030 ELY

                     December 1969
     For sale by the Superintendent of Documents, U.S. Government Printing Office
                 Washington, D.C. 20402 - Price $1.60

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'miROfflSEJTAL PROTECTION AGENCY

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                             FOREWORD
This is a collection of individual papers dealing with the closely
related topics of (a) concentrations of nitrates occurring in sub-
surface agricultural waste waters, (b) the source of nitrates, and
(c) possible methods for controlling or removing them.  The work
reported herein all deals with subsurface agricultural waste waters
of the San Joaquin Valley in California, but much of the information
may have general application.  The papers all were prepared for, and
presented originally at, the National Fall Meeting of the American
Geophysical Union on December 16, 1969, in San Francisco.  Since
that time a few revisions have been made by the authors, who are
solely responsible for the contents, but no editing was done in
connection with publication of the papers as a collection.

In the interval between preparation of the papers and printing of this
collection, the Federal Water Pollution Control Administration has
shortened its name to Federal Water Quality Administration.

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                        TABLE OF CONTENTS
GENESIS AND SCOPE OF INTERAGENCY COOPERATIVE STUDIES OF
  CONTROL OF NITRATES IN SUBSURFACE AGRICULTURAL WASTE
  WATERS--Edgar P. Price

  Introduction 	 ..... 	     1
  Drainage Problem of the San Joaquin Valley ........     2
  San Luis Drain	     5
  Protecting San Francisco Bay	     6
  Quantity and Quality of San Joaquin Valley Drainage  . .     7
  Research Program Formulation 	    11
  Conclusion	    12
  Papers Cited 	    14

PREDICTING CHANGES IN NITROGENOUS COMPOUNDS IN SOIL-WATER
  SYSTEMS--Marvin J. Shaffer, Gordon R. Dutt, and
  William J. Moore

  Introduction	    15
  Methods and Theory	    15
  Discussion of Results  	    22
  Summary	    22
  Papers Cited 	    28

THE MOVEMENT OF NITROGENOUS FERTILIZERS THROUGH SOIL
  COLUMNS--John W. Williford, Thomas C. Tucker, Robert L.
  Westerman and Doyle R. Cardon

  Introduction	    29
  Methods and Material	    29
  Results and Discussion 	    32
  Summary	    39

AGRICULTURAL NITRATE REDUCTION AT A WATER TABLE—
  L. S. Willardson and Burl D. Meek

  Introduction	    41
  Soil Column Experiment	    42
  Field Experiment	    42
  Results	    43
  Discussion	    47
  Summary	    52

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MONITORING NUTRIENTS AND PESTICIDES IN SUBSURFACE
  AGRICULTURAL DRAINAGE—L. R. Glandon, Jr., and
  L. A. Beck

  Introduction 	    53
  San Joaquin Valley Drainage Investigation  .......    53
  Objectives of Nutrient and Pesticide Investigations  .  .    54
  Area of Investigation and Methods	    54
  Physiographic Positions  	    57
  Soils	    57
  Selection of Tile Drainage Systems	    58
  Tile Drainage Systems  	    58
  Sampling	    60
  Analyses	    60
  Calculations 	    60
  Results of Drainage Monitoring Program 	    61
  Soil Nitrogen Investigations 	  .    62
  Results of Soil Nitrogen Investigations   	    67
  Effects of Agricultural Practices  	    67
  Pesticides in Subsurface Agricultural Drainage 	    68
  Usage	    71
  Discussion	    71
  Summary and Conclusions  	    76
  Papers Cited 	    78

DESALINATION OF IRRIGATION RETURN WATERS—Bryan R. Sword

  Introduction	    81
  Water Quality	    81
  TDS Control	    81
  Reverse Osmosis	    85
  Electrodialysis   	    94
  Summary	   104
  Papers Cited	   105

BACTERIAL DENITRIFICATION OF AGRICULTURAL TILE DRAINAGE--
  Thomas A. Tamblyn, Perry L. McCarty and Percy P. St. Amant

  Introduction 	   107
  Process Considerations	   107
  Process Configurations	   108
  Experimental Procedures  	   109
  Anaerobic Ponds   	   109
  Anaerobic Filters  	   112
  Analytical Techniques and Sample Gathering 	   112
  Results and Discussion 	   115
  Conclusion	   119
  Papers Cited 	   120
                                   11

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ALGAL NUTRIENT RESPONSES IN AGRICULTURAL WASTE WATER—
  James F. Arthur, Randall L. Brown, Bruce A. Butterfield,
  and Joel C. Goldman

  Introduction 	   123
  Methods and Materials  	   126
  Results and Discussion 	   128
  Summary	   139
  Papers Cited 	   141

THE EFFECTS OF NITROGEN REMOVAL ON THE ALGAL GROWTH
  POTENTIAL OF SAN JOAQUIN VALLEY AGRICULTURAL TILE
  DRAINAGE EFFLUENTS—Randall L. Brown, Richard C. Bain, Jr.,
  and Milton G. Tunzi

  Introduction	   143
  Methods and Materials	   143
  Results	   145
  Discussion	   153
  Papers Cited 	   155

HARVESTING OF ALGAE GROWN IN AGRICULTURAL WASTE WATERS—
  Bruce A. Butterfield and James R. Jones

  Introduction 	   157
  Flocculation-Sedimentation Study 	   157
  Discussion	   158
  Pilot Harvesting Studies 	   160
  Future Work	   162
  Conclusions	   162

COMBINED NUTRIENT REMOVAL AND TRANSPORT SYSTEM FOR TILE
  DRAINAGE FROM THE SAN JOAQUIN VALLEY--Joel C. Goldman,
  James F. Arthur, William J. Oswald, and Louis A. Beck

  Introduction	   165
  General Aspects of Proposal  	   165
  Suggested Modifications to Improve In-Line Treatment . .   169
  Summary	   178
  Recommendations  	   179
  Appendix	   180
                                  m

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                      GENESIS AND SCOPE OF
               INTERAGENCY COOPERATIVE STUDIES OF
                     CONTROL OF NITRATES IN
              SUBSURFACE AGRICULTURAL WASTE WATERS

                               By

                         Edgar P, Price
Introduction

The program of the United States Bureau of Reclamation to construct
San Luis Drain, the plans of the California Department of Water
Resources to construct a San Joaquin Valley master drain, and the
concern of these two agencies and that of the Federal Water Pollution
Control Administration for water quality in San Francisco Bay prompted
the three agencies in 1967 to launch a cooperative investigation of
methods for removing nitrates from subsurface agricultural waste
water.  The investigation soon broadened technically and organiza-
tionally to include examination of the source of the nitrates and
the changes in nitrate form which might occur spontaneously or
which might be induced as,the subsurface water is collected, and
conveyed through California's San Joaquin Valley to the head of the
San Francisco Bay System.

In addition to the three agencies already mentioned, parts of the
overall investigation are being conducted or supported by the
Agricultural Research Service, the Soil Conservation Service, the
Office of Saline Water, the University of Arizona, and the
University of California at Davis.  Faculty members from both
Stanford University and the University of California at Berkeley
are serving as consultants.  Other governmental organizations,
educational institutions, and private firms are performing
services or doing related work.  The cost of the program will be
approximately $3 million, most of which will be spent during the
3-year period 1967-70.  Some parts of the research will continue
past 1970.  The results will be generally applicable in most, if
not all, irrigated areas which dispose of their subsurface agri-
cultural waste waters to a water body, either surface or underground.

This paper gives the background and an overview of the entire
investigation.  The several other related papers which follow give
detailed information about specific experiments.
  U.S. Bureau of Reclamation, Sacramento, California

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Drainage Problem of the San Joaquin Valley

It was the saline water drainage problem of the San Joaquin Valley
which drew both the Department of Water Resources and the Bureau
of Reclamation into the interagency cooperative waste water treat-
ment study.  For over a century, irrigated agriculture has been
expanding in the San Joaquin Valley which, as illustrated on
figure 1, forms the southern portion of California's Central
Valley.  This growth has been paralleled by a rising concern over
the problems of drainage; not merely the problem of keeping excess
water out of crop root zones but of protecting the sources of
irrigation water, both surface streams and ground water, from
harmful concentrations of salt contributed by agricultural return
flows.  For years, irrigators have sought an alternative to the
San Joaquin River as a drainage outlet to remove salts from the
almost completely enclosed San Joaquin Valley.  Aided by studies
of the California Department of Water Resources and the United
States Bureau of Reclamation, the irrigators1 efforts were rewarded
in 1960.  In that year Congress authorized construction of facili-
ties to import additional water to the 500,000-acre San Luis Unit
service area on the west side of the San Joaquin Valley and included
provision for construction of a canal (San Luis Drain) to convey
drainage waters back to the western Sacramento-San Joaquin E'elta
near Antioch.  These features are shown on figure 2.  At about the
same time the voters of California approved the long-range State
Water Plan which incorporated a proposed master drain to dispose
of saline waters from all portions of the San Joaquin Valley
which might require such service.

The proposed State and Federal drainage facilities were not
intended to be competitive; the Federal Drain was to serve only
the San Luis Unit service area and was to be built only if the
State's master drain did not materialize.  After independent
studies of many possible solutions, both agencies decided upon
conveyance of the saline waters to a point near the city of
Antioch where they believed the saline drain waters could be dis-
charged without significantly increasing the salinity of the
receiving waters.  The bases for selecting this plan are recorded
in a report entitled "San Joaquin Master Drain" (1)^ issued by
the Department of Water Resources and a report entitled "Alternative
Solutions For Drainage" (2) issued by the Bureau of Reclamation.

Beginning in 1964, the Department of Water Resources and the
Bureau of Reclamation cooperated diligently in an attempt to
bring about construction of a master drain by the Department to
which the Bureau would contribute financially in return for
  Parenthetical numbers refer to literature cited.

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SACRAMENTO RIVER
                                  i.-,J>->'/•),'*,
                                  SIERRA  NEVADA  MOUNTAINS
      SACRAMENTO-
      SAN JOAQUIN
      DELTA
SAN JOAQUIN,VALLEY
SAN JOAQUIN RIVER
             HE&.
   SAN LUIS  DAM
                        Figure I. Location Map

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    'SAN PABLO BAY


                  ?SUISUN BAY
                             SACRAMENTO-SAN JOAQUIN DELTA
                                      DELTA-M ENDOTA CANAL
                                  SAN  LUIS DRAIN
                                  %«KESTERSON
                                      REGULATING RESERVOIR

                                      Los Bonos
SAN FRANCISCO
  BAY
  NORTHERN PORTION \
CALIFORNIA AQUEDUCT
           SAN LUIS DAM
          O'NEILL FOREBAY
                 SAN LUIS CANAL
                           SERVICE AREA
                       SOUTHERN  PORTION
                     CALIFORNIA AQUEDUCT
Firebaugh




 Tranquillity


          Fresno
                                                  ettleman City
          Figure 2.   San  Luis Unit and  Related Facilities

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drainage disposal service for the Federal San Luis Unit.  During
this period the Department recognized the need to study ways of
removing nitrates from the drainage waters and in 1965 began
negotiations to secure a research grant from the Federal Water
Pollution Control Administration.  At this time the Bureau of
Reclamation was expecting to contribute financially to the
research effort as part of its share of the cost of the master
drain but not to participate actively.  In early 1967, however,
the picture changed drastically when the Department decided to
defer construction of a master drain indefinitely because of the
unwillingness of many local agencies in the San Joaquin Valley to
contract for drainage disposal service.  The Bureau then began
constructing San Luis Drain and, as a corollary thereto, preparing
itself to cope with nitrates in the drain waters if these sub-
stances were to prove deleterious.  Since the Department still
expected to someday construct and operate a drainage facility in
the San Joaquin Valley it wished to pursue the nitrate research
program it had set in motion.

San Luis Drain

San Luis Drain, which the Bureau of Reclamation now is constructing
in the San Joaquin Valley, will be a concrete-lined canal extending
188 miles northward from near Kettleman City to the western edge
of the Delta near Antioch.  About two-t;hirds of the way from
Kettleman City to Antioch, near Gustine, a regulating reservoir
called Kesterson Regulating Reservoir will be constructed as an
integral part of the drain.

The drain throughout its length will be hydraulically isolated
from all surface and ground water so that it will neither contribute
water to, nor receive water from, any surface channel or ground-
water body it crosses.  The water flowing in San Luis Drain will
be subsurface agricultural waste water received under contract and
discharged from drainage collector systems.

The capacity of San Luis Drain will increrase from 100 c.f.s. at
its southern beginning to 300 c.f.s. at its entrance to Kesterson.
From Kesterson to Antioch the capacity of the drain will be a
uniform 450 c.f.s.  Kesterson Reservoir will function initially as
a simple holding pond in which the early flows reaching San Luis
Drain will be held until construction of the northern portion of
the drain is complete and discharge to the upper end of the San
Francisco Bay system begins.  Using Kesterson Reservoir in this
manner will permit drainage of land to start soon but will allow
an extra year or two in which to complete the nitrate control
research program before discharge near Antioch begins.

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In 1967, when the research program was initiated, the construction
of San Luis Drain was scheduled as a three-step process:  Firstly,
65 miles of the drain from Tranquillity to Kesterson Reservoir
and a portion of the reservoir were to be completed by December
1969; secondly, the southernmost segment of the drain between
Tranquillity and Kettleman City was to be completed by December
1970; and lastly, the remainder of Kesterson Reservoir and the
drain from the reservoir to Antioch were to be completed by
December 1971.  This was the construction schedule to which the
research schedule was geared.  Reductions in Federal appropria-
tions have forced delays of 2 years or more in all phases of San
Luis Drain construction, but the research program has been kept
on schedule and conclusions will be available in 1970.

Protecting San Francisco Bay

The Federal Water Pollution Control Administration is interested
in the interagency cooperative study of the role of nitrates in
subsurface agricultural waste water as a means of protecting the
quality of water throughout the San Francisco Bay system and the
Sacramento-San Joaquin Delta.  In 1962 the Bureau asked the
Administration (then a part of the Public Health Service) to look
into the subject.  In addition, local interests in the Bay Area
opposed the drainage plans of the Bureau and the Department, and
these agencies urged that a study be made of the possible effects
on water quality.  The opponents maintained that such drainage
discharge would:   (a) usurp assimilative capacity of the Bajr
system which properly should be reserved for the individual and
corporate residents immediately adjacent to San Francisco Bay;
(b) significantly increase the salinity of the receiving waters in
the vicinity of Antioch thereby further shortening the intermittent
periods when such waters now are suitable for municipal, industrial,
or agricultural use; (c) compound the problem of pesticides, and
(d) accelerate catastrophically the eutrophication of the Bay-
Delta estuarine combination.

In response to these requests for study and allegations of damages,
the Federal Water Pollution Control Administration undertook a
comprehensive study of the probable effect of the San Joaquin
Valley Master Drain on San Francisco Bay and in January 1967
published its report (3).  Essentially, the report concluded that
the fears related to assimilative capacity, salinity, and pesti-
cides were greatly exaggerated but that the anticipated nitrate
content of the drain waters might produce extensive algal blooms
in the receiving waters.  One of the principal recommendations of
the Federal Water Pollution Control Administration, therefore, was
that a feasible method of nitrate removal be worked out before any
agricultural drainage discharge to the Bay system be allowed,.  The

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Administration estimated that 3 years of research would be required
to select a removal method from amongst several which had shown
promise on a laboratory scale and to design a practical facility
capable of removing nitrates under field conditions.

Quantity and Quality of San Joaquin Valley Drainage

The most recently compiled estimates of the quantities of sub-
surface agricultural waste water which will have to be disposed
of from the San Joaquin Valley are given in table 1.  These
estimates were issued by the San Joaquin Valley Drainage Advisory
Group  (4) composed of individuals drawn from organizations engaged
in water management in all parts of the San Joaquin Valley.  The
table basically is a combination of estimates made by the Depart-
ment of Water Resources and the Bureau of Reclamation.  The range
of dates indicates that such estimates involve a large measure of
judgment.  The year-to-year increase in subsurface agricultural
waste water entering a drainage disposal system depends upon how
and when individual irrigators install tile drainage as well as
upon when and where they begin application of the additional irri-
gation water supplies made available by the major State and Federal
water importation projects.  Some information on the status and
prospects of tile drain installations in the San Joaquin Valley
has been reported by the Soil Conservation Service (5) and by
William R. Johnston (6), the drainage expert on the staff of
Westlands Water District located in the Federal San Luis Unit
service area.

Table 2 shows the concentrations of various substances which are
anticipated for the drainage water which will flow in San Luis
Drain.  These probably are reasonably representative of the con-
centrations which will occur in discharges from any drainage
disposal facility serving other areas of the San Joaquin Valley,
too.  The initial concentrations of all salts are higher than
those anticipated 50 years hence.  This is because there exist
accumulations of these salts which will be removed by draining
away the shallow ground water and leaching the soils.  Afterwards
the concentrations of salts in the drainage effluents should be
just sufficient to make the rate of disposal equal to the rate of
input for each salt.  Those substances for which no change in con-
centration is anticipated either have not been accumulating or
else accumulations of them cannot be removed by draining and
leaching.

The macronutrients, nitrogen and phosphorous,  of course, are the
substances of primary interest when considering eutrophication.
The Federal Water Pollution Control Administration in its

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            Table 1.   Estimated annual agricultural
               waste  water disposal requirement


Yearl
1970, 1975
1980, 1990
1990, 2005
2000, 2020
2010, 2035
2020, 2050

San
Luis
Unit 2
5
53
123
155
162
162
Annual Requirement
(1,000 A/F)
•
: Other parts
: of Valley 3
82
200
318
401
414
421

•
*
: Total
87
253
441
556
576
583
1  Earliest and latest estimated dates.
2  USER estimate.
3  DWR estimate.

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                Table 2.   Estimated concentrations
                     of chemical substances in
                       San Luis Drain waters
                                      1970                 2020
                                   Conditions           Conditions
          Substance                  mz./l.               n>fi./l.._

Total dissolved solids               7,000                3,000

Salts

    Sulfate

    Sodium

    Chloride

    Calcium

    Magnesium

    Bicarbonate

    Potassium

    Boron

 Nutrients

    Total Nitrogen                      20                   20

    Total Phosphate                      0-15                 0.15
3,000
1,500
1,200
300
200
200
20
10
700
700
900
100
50
100
10
3
 Pesticides
                                        <0.001              <0.001

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previously cited report on the effect of the San Joaquin Master
Drain identified nitrogen as the limiting nutrient in the case of
San Francisco Bay and estimated the maximum safe concentration
of nitrogen as 2.0 milligrams per liter if unacceptable algae
blooms are to be avoided in the Bay and Delta waters.  This has
been adopted as the goal of the interagency cooperative program
for nitrate control or removal, and it means that methods must
be developed to reduce the nitrogen concentrations in the drainage
waters by 90 percent.

The latest comprehensive study of the Bay System's water quality
problems and possible control methods (7) states that neither
nitrogen nor phosphorus is growth limiting in San Francisco Bay
and the Delta.  Furthermore, the report indicates that even with-
out any nitrate removal the subsurface agricultural waste water
from San Luis Drain would be less than one-half of one percent of
the total nitrogen loading in the Bay.  The report postulates that
unspecified biostimulants, if not controlled or eliminated, will
result in undesirable eutrophication.  This, apparently, indicates
a need to search for biostimulants rather than nitrogen removal
methods.  However, since the biostimulants have not been identified
and the concept is general, the growth-limiting factor in*San
Francisco Bay may not be the absence of a biostimulant but the
presence of a biodepressant (a negative biostimulant).  This might
be a toxic substance coming from municipal and industrial waste
discharges or the turbidity of the waters.

The contrast between the view of one agency that nitrogen is growth-
limiting in San Francisco Bay and the view of another agency that
it is not, simply confirms that the conclusion of Professor Charles M.
Weiss (8) regarding lakes and reservoirs also applies to the San
Francisco Bay estuarine system:  "The rate of trophic response of
each lake or reservoir to changes in macronutrient levels involves
not only nutrient change, but also the total chemical and physical
characteristics of the particular basin,"

In view of the uncertainties surrounding the eutrophic process
generally and eutrophication in San Francisco Bay in particular,
the nitrogen control and removal experiments have and will be
continued.  They may or may not be applicable to San Joaquin
Valley subsurface agricultural drainage discharges but whoever
operates a facility making such a discharge to San Francisco Bay
should be prepared to institute procedures to control nitrogen
levels if necessary.  Furthermore, such removal or control methods
may have utility elsewhere even if never needed in connection with
San Francisco Bay.
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Research Program Formulation

From December 1963 on, the California Department of Water Resources
had been studying algae stripping as a promising process for re-
moving nitrates from drainage water.  In the course of this effort
the Department made application to the Federal Water Pollution
Control Administration for a financial grant and also had requested
the use of some land owned by the United States along the Delta-
Mendota Canal of the Bureau of Reclamation for construction of an
experimental facility.  The site, near Firebaugh, was selected
because it was adjacent to a drain sump receiving water from tile
drain lines underlying approximately 400 acres of farmland typical
of the lands in the San Joaquin Valley through which ultimately
will need drainage to remain in agricultural production.  The
owners of the land had agreed to let the Department of Water
Resources divert as much of the subsurface agricultural waste
water as would be needed for experiments.  In early 1967, the
Department of Water Resources announced deferment of construction
of a San Joaquin Valley Master Drain and thus set in motion the
program of the Bureau of Reclamation to construct San Luis Drain.
Another result of this switch in construction agencies was to
alter the role of the Bureau of Reclamation in the nutrient
research program from that of a financial supporter to that of an
active participant.  This was necessary, of course, because Bureau
personnel would be operating and maintaining San Luis Drain and
whatever treatment facilities may prove to be necessary.

In January 1967 the three agencies met to lay out the research
program and synchronize the research and drain construction programs,
There was unanimous agreement on the importance of the work, and
there was quick agreement to implement the research program which
the Department of Water Resources had planned for the Firebaugh
site.  A contract was signed by the three parties calling for a
3-year program of research into the removal of nitrates by the
algae-stripping method (sometimes called the biomass production
and harvesting method)--that is, the forcing of maximum growth of
algae in drain water held in special ponds followed by separation
of the algae from the water.  The contract also specified that a
quick evaluation would be made of the potentialities of biological
denitrification--a term which refers to the reduction of nitrates
by bacterial action in anaerobic conditions.

The meeting in January 1967 to establish the research program was
characterized by an eagerness on the part of all involved agencies
to go the extra mile.  As a result,  the individual agencies were
suggesting additional and related experiments which they alone or
in combination with some fourth agency, would finance and conduct.
The Federal Water Pollution Control Administration in cooperation
                                  11

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with the Office of Saline Water decided to test desalting units on
the San Joaquin Valley's brackish water, and they chose a reverse
osmosis unit and an electro-dialysis unit for this purpose.  The
Bureau of Reclamation contracted with the Universities of California
(Davis) and Arizona to develop a digital computer program modeling
the nitrogen transformations which take place in the soil-water
systems and to verify the model with a series of field plot and
lysimeter experiments.  Both the Federal Water Pollution Control
Administration and the Bureau of Reclamation contracted with
private concerns for pilot research on resins which might selec-
tively reject the nitrate ion.  The Department of Water Resources
continued its program of sampling drainage sumps in many parts of
the San Joaquin Valley, and the Federal Water Pollution Control
Administration instituted intensive sampling of a limited number
of selected drain sumps.  The Federal Water Pollution Control
Administration also financed a pilot study of denitrification in
sulfur columns at the California Institute of Technology.  This
was the scope of the comprehensive program which the three
agencies put down on paper in January 1967 and which was well
underway 6 months later.

In subsequent months the Federal Water Pollution Control Adminis-
tration greatly expanded the biological denitrification experiments
at the Firebaugh site because of the promise the method showed.
Also, the Bureau of Reclamation, the Agricultural Research Service,
and the Soil Conservation Service in cooperation with a local
valley farmer began an experiment to see if a useful degree of
biologic denitrification could be achieved right in the soil of
the irrigated fields simply by designing and installing tile drains
which would be submerged and therefore anaerobic at all times.

Conclusion

The individual experiments have produced much information, and a
lot of it is recorded in the other 11 selected papers which follow.
As yet, no attempt has been made to reach conclusions regarding
the overall control of nitrates in the subsurface agricultural
waste waters of the San Joaquin Valley.  This will come in the
next few months after most of the experiments are completed and
the results fully assessed.

From the viewpoint of those engaged in the development and pro-
tection of natural resources, however, the evolution and execution
of a program of this sort is significant.  In this day and age,
dealing with natural resources inevitably involves coping with an
increasing complexity of inter-related causes and effects; inte-
grating work from an increasing number of scientific specialities;
                                  12

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keeping abreast of an increasing array of technical problem-solving
tools and techniques; and last, but certainly not least, dealing
with a rapidly-growing number of organizations.  This program is
one example of how this may be approached.

From the viewpoint of a manager in natural resources development
the aspects to be emphasized are:

     (a)  The comprehensive nature of the experimental program
which aims to determine not only how nitrates can be removed most
economically from subsurface agricultural waste water but where
the nitrates originate, what transformations they undergo in the
soils, in the drain canal, and in holding ponds; and what possi-
bilities exist for influencing the sources and the transformations
in order to reduce--or perhaps even eliminate--the need for exten-
sive facilities solely to remove nitrates.

     (b)  The effective way in which a wide range of private citi-
zens, governmental agencies, universities, and people--from
individual farmers to scientific consultants--are bringing their
knowledge, experience, and other resources to bear on this problem
of controlling nitrates in subsurface agricultural waste water.
About every 6 months a meeting is held to review progress on all
experiments and exchange data; in between these meetings there are
many smaller meetings, and of course, the fact that many of the
experiments are located at the interagency Firebaugh site guarantees
a high degree of cross-fertilization of ideas.

     (c)  The cooperative nature of the program which will cost in
the neighborhood of $3 million over a 3-year period from 1967-70.
About one-third of this amount is involved in the three-party
contract involving the Department of Water Resources, the Federal
Water Pollution Control Administration, and the Bureau of
Reclamation.  The other two-thirds of the program is administered
by the individual agencies but in such a manner as to make a timely
and significant contribution to the comprehensive program.
                                  13

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Papers Cited

(1)  "SAN JOAQUIN MASTER DRAIN," Bulletin 127 (Preliminary Edition),
     Department of Water Resources, The Resources Agency, State of
     California, January 1965.

(2)  "ALTERNATIVE SOLUTIONS FOR DRAINAGE, SAN LUIS UNIT, CENTRAL
     VALLEY PROJECT, CALIFORNIA," U.S. Department of the Interior,
     Bureau of Reclamation, February 1964.

(3)  "SAN JOAQUIN MASTER DRAIN," Southwest Region, Federal Water
     Pollution Control Administration, U.S. Department of the
     Interior, January 1967.

(4)  "FINAL REPORT," San Joaquin Valley Drainage Advisory Group,
     P. 0. Box 2385, Fresno, California  93723,  January 1969.

(5)  MILLER, ROBERT S. and ANDERSON, CARL F., "Factors Affecting
     Drainage on the West Side of the San Joaquin Valley," a
     progress report by the Soil Conservation Service, U.S.
     Department of Agriculture, July 11, 1966.

(6)  JOHNSTON, WILLIAM R., "Drainage Problems and the Proposed
     Solution for a Large Irrigated Area in the San Joaquin Valley
     of California  (USA)," Fourth Technical Conference on Irrigation,
     Drainage, and Flood Control, U.S.I.C.I.D.,  Phoenix, Arizona,
     March 1968.

(7)  "SAN FRANCISCO BAY-DELTA WATER QUALITY CONTROL PROGRAM," FINAL
     REPORT - Abridged Preliminary Edition - to the Water Resources
     Control Board, State of California, March 1969.

(8)  Journal, American Water Works, August 1969, pages 387-391.
                                  14

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               PREDICTING CHANGES IN NITROGENOUS
                COMPOUNDS IN SOIL-WATER SYSTEMS
                                By
               Marvin J. Shaffer, Gordon R. Dutt,
                      and William J. Moore
 Introduction

 A digital computer program was developed which models soil-water
 systems with respect to nitrogen transformations, including hydrol-
 ysis of urea, immobilization-mineralization of ammonia and organic
 nitrogen, and immobilization of nitrate nitrogen.  Transformation
 rate equations were derived by applying techniques of systems and
 statistical analysis and using selected data from the literature.
 Simultaneous integration of the equations over time generates pre-
 dicted concentrations for urea-N, organic-N, ammonia-N, and
 nitrate-N in the system.  Comparisons were made of predicted and
 observed data for several soils having different textures and
 various moisture contents, temperatures, and fertilizer applications.
 This procedure yielded simple correlation coefficients of 0.99, 0.97,
 and 0.97 for the previously mentioned nitrogenous types,
 respectively.

 Nitrogen is an important component of most soil-water systems.  It
 is involved in a variety of biochemical and physical processes
 occurring in soils.  Excessive accumulations or deficiencies of one
 or more nitrogenous species may lead to high nitrogen concentrations
 in agricultural drainage waters and nitrogen deficiencies or exces-
 sive foliar growth of plants.  A model predicting the concentrations
 of nitrogenous species occurring in soil-water systems would aid in
 planning management criteria for pollution control and fertilizer
 programs.  This study was concerned with the development of a
 digital computer model based on data available in the literature,
 to serve as part of a more comprehensive model for soils.

Methods and Theory

To simplify the investigation discussed above, the soil-water system
was restricted in several aspects.  Leaching and plant uptake of
  Graduate Associate,Professor,and Graduate Associate, respectively.
  University of Arizona, Tucson, Arizona.  This research was supported
  in part by the U.S. Bureau of Reclamation contract 19-06-D-6464.
  Arizona Agr. Exp. Sta. Technical Paper.
                                  15

-------
nitrogen were neither considered nor allowed in the model.  The
assumption was made that denitrification is not a significant
process in the system as defined (9).   To eliminate many acid
soil reactions, only alkaline soils were considered.  Further, it
was assumed that nitrogen and ammonium fixation and nitrite con-
centration are negligible.

The basic nitrogen transformation pathways considered in this model
are illustrated in figure 1.  The peripheral arrows represent
inputs to the model.  Urea hydrolysis denotes the conversion of
urea to ammonia nitrogen.  The mineralization-immobilization path-
way accounts for the net conversion of ammonia to organic nitrogen
or organic to ammonia nitrogen.  Nitrification represents the net
production of nitrate from ammonia nitrogen.  Net reduction of
nitrate to ammonia nitrogen probably would not occur in this
restricted system.  Immobilization of nitrate nitrogen is described
by the nitrate-N pathway.

These pathways designate nitrogen transformations in the model
system.  Modification of this system could allow incorporation of
additional pathways.

The basic inputs and outputs of the model are illustrated in figure 2.
Initial soil conditions with respect to concentrations of nitrogenous
species, temperature, moisture, and carbon to nitrogen ratio repre-
sent one set of inputs.  Others include additions of urea, ammonia,
organic, and nitrate nitrogen with time.  Moisture and temperature
changes with time were allowed.  Concentrations of the nitrogenous
species in the system with time were considered as outputs from the
model.

Experimental data needed to develop mathematical relationships for
the transformation pathways were obtained from the literature.  Data
suitable for the urea hydrolysis pathway were obtained from papers
by Broadbent, Hill, and Tyler  (4), and Overrein and Moe  (8).  Work
by Broadbent (2 and 3) and Alexander (1) provided data for the
mineralization-immobilization pathway.  Nitrification data were
obtained from Broadbent, Tyler, and Hill (5), and Justice and
Smith  (7).  Finally, work by Broadbent  (3) provided nitrate immobi-
lization data.

Since nitrogen transformations usually proceed at a slow rate,
equilibrium considerations used in earlier models, e.g.  (6), were
  Parenthetical numbers refer to literature cited.
                                  16

-------
               Organic-N
Mi nerali zat ion-
Immobi1i zat ion
1
               Ammon i a-N
       Urea
    Hydrolys is
   L
                Urea-N
                   t
              Nitrate-N
              Immobi1i zat ion
                       Nitrate-N
Ni tri fication
     Fig. 1.  Biochemical and Chemical Pathways Within the
                          System Model
                             17

-------
                     Ni trogen
                    Ammendments
    Water
     Heat

                       Soil
                     (System
                      Model)
                        1
Initial  Soi1
 Cond i t ions
                     Ni trogen
                     in  Soi1
Fig.  2.   Basic Inputs and Outputs of the System Model
                           18

-------
abandoned in favor of a kinetic approach.  Attempts were made to
derive transformation rate equations for each pathway as a function
of the variables indicated below.

     Rate=f (concentrations of urea-N, NH--N, organic-N, and NO...-N;
               temperature; moisture; C: N ratio; texture; pH)

This procedure was simplified by applying computerized multiple
linear regression techniques.  In general, the form of each rate
equation was as follows:

               R=C + b^

     Where R is rate (dependent variable).
     C is a constant (Y-intercept).
     x^ is an independent variable.
     bn is a constant (regression coefficient).

Various combinations of independent variables were tried to obtain
the best fit as evidenced by the multiple correlation coefficient
and F ratio.  Only those variables or variable combinations making
significant contributions to the regressions were included in the
final equations.  The primary objective was to obtain equations
describing the effects of the independent variables and account for
their interactions.

At this point, it is well to note that at temperatures less than
10° C. and/or nitrogen concentrations below 10 p.p.m., exponential
rate functions were used to adjust the output of the regression
rate equations.  This procedure yielded better data fits near these
boundaries.  Similarly, exponential moisture functions were included
to correct the regression equations for moisture contents below
10 bars tension.  Moisture content was not found to be a significant
variable above this tension.  Also, an expression including C:N
ratio, derived from work done by Alexander (1) and Broadbent (2),
adjusted the output of the mineralization-immobilization regression
equations for changes in C:N ratio of the organic residue.  A
summary of the final regression equations and statistical tests
appears in table 1 and table 2.

Next, it was necessary to solve the equations simultaneously to
obtain changes in nitrogen concentrations in the model.  For a given
time interval, the same initial conditions were utilized by each
rate equation.  The computed changes in concentration from each
equation were used to determine the initial concentrations for the
next interval.  Predicted nitrogen concentrations with time were
approximated by successively increasing the number of time intervals
included between times 1\ and T(T-T,=1 day) and repeating the
                                  19

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calculations. This process was continued until the concentration
of each nitrogenous species at ^2 agreed to within 0.5 p.p.m. of
its previous value. That is, the system converged. A generalized
block diagram of the computer program illustrating the method of
solving the equations appears in figure 3.

Next, the predicted nitrogen concentrations were compared with the
observed data used to derive the rate equations. Adjustments in
certain coefficients were necessary to improve the fit in the
assembled model. Interactions between the independently derived
rate equations could account for the corrections needed. A
summary of changes made in coefficients appears in table 3.

Discussion of Results

Techniques of data pairing were employed to test the reliability of
the model. Sets of observed and predicted values for each nitrog-
enous species studied were compared by using a least squares linear
regression analysis to obtain the simple correlation coefficient,
the regression coefficient, the Y-intercept, and the standard error
of estimate. This observed data was a combination of data used to
derive the model together with all other available data applicable
to the model. Results of this analysis for each of the four nitrog-
enous types studied are given in table 4. Data obtained from*dupli-
cate runs were omitted to avoid inclusion of many similar points.
Data represented results from several different soil series and
types. The lower correlation coefficient for organic nitrogen may
have been due to the relatively narrow data range considered.

Typical observed and predicted curves for urea, organic, ammonia,
and nitrate nitrogen concentrations versus time are given in figures
4, 5, 6, and 7. Some runs gave better agreement, while others did
not agree as well. This model can be used to predict changes in
concentrations of nitrogenous species in soil-water systems under-
going incubation. Of more importance is its potential application
to dynamic soil-water systems of practical interest. Such a model
is currently under development.

Summary

The objective of this research was the development of a digital
computer model predicting nitrogen concentrations in soil-water
systems. The system was restricted by certain assumptions and
limitations. After establishing primary pathways for nitrogen
transformations, corresponding mathematical equations were derived
using a statistical analysis of data from the literature. These
equations were combined and solved in a computer program which
became the basic model. The model was verified by comparing its
predicted output with observed data from the literature.
22
-------
Start
J
I nput
Sect ion
Ammon i a-N
Sect!on
1
Nitrate-N
Sect i on
Yes
Output
Section
Urea-N
Sect ion
Organic-N - C:N
Ratio Section
Yes
Plotting
Subrout i ne
( Stop j
Fig. 3- Generalized Block Diagram of the
Computer Program
-------
Table 3« Summary of Corrections Made in Regression Coefficients
Equation C:N Ratio bl b2 b3

Urea Hydrolysis NC* NC

Mineralizat ion- ~
Immobilization <23 NC NC 1.60-10

223 NC NC 7-83-10"1

Nitrification <23 NC 4.50-10° NC

223 8.00-10"1* 2.38-10 -2.10-10°

Nitrate-N
Immob i 1 izat ion
<23
£23
NC
NC
NC
NC
NC
NC
* NC = No Change.
24
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50
Fig. 4.
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100
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Typical Observed and Predicted Curves

For Organic-N
26
-------

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en
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* = Predicted

o o
*
2
a
*
0
1 1 1 1 1
10 20 30 40 50
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Fig. 7- Typical Observed and Predicted Curves for
Nitrate-N
27
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Papers Cited

(1) Alexander, M., INTRODUCTION TO SOIL MICROBIOLOGY, 1st. Edition,
New York: John Wiley and Sons, Inc., 1961.

(2) Broadbent, F. E., "ORGANIC MATTER," The Yearbook of Agriculture
1957, (1957), 151-157.

(3) Broadbent, F. E., "INTERCHANGE BETWEEN INORGANIC AND ORGANIC
NITROGEN IN SOILS," Hilgardia, Vol. 37 (1966), 165-180.

(4) Broadbent, F. E., Hill, G. N., and Tyler, K. B., "TRANS-
FORMATIONS AND MOVEMENT OF UREA IN SOIL," Soil Sci. Soc. Amer.
Proc., Vol. 22 (1957), 303-307.

(5) Broadbent, F. E., Tyler, K. B., and Hill, G. N., "NITRIFICATION
OF AMMONIACAL FERTILIZERS IN SOME CALIFORNIA SOILS," Hilgardia,
Vol. 27 (1957), 247-267.

(6) Dutt, Gordon R., "EFFECT OF SMALL AMOUNTS OF GYPSUM IN SOILS
ON THE SOLUTES IN EFFLUENTS," Soil Sci. Soc. Amer. Proc.,
Vol. 28 (1964), 754-757.

(7) Justice, J. K., and Smith, R. L., "NITRIFICATION OF AMMONIUM
SULFATE IN A CALCAREOUS SOIL AS INFLUENCED BY COMBINATIONS OF
MOISTURE, TEMPERATURE, AND LEVELS OF ADDED NITROGEN," Soil Sci.
Soc. Amer. Proc., Vol. 26 (1962), 246-250.

(8) Overrein, L. L. and Moe, P. G., "FACTORS AFFECTING UREA
HYDROLYSIS AND AMMONIA VOLATILIZATION IN SOIL," Soil Sci. Soc.
Amer. Proc., Vol. 31 (1967), 57-61.

(9) Waksman, Selman A., SOIL MICROBIOLOGY, New York: John Wiley and
Sons, Inc., 1952.
28
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THE MOVEMENT OF NITROGENOUS FERTILIZERS
THROUGH SOIL COLUMNS
By

John W. Williford, Thomas C. Tucker,
Robert L. Westerman and Doyle R. Cardon1
Introduction

Economic pressures have forced farmers to strive for maximum yields.
As a result, gigantic amounts of fertilizers are being applied each
year and the rates will probably increase each year. In the
Continental United States over 6.5 million tons of N were applied
last year. In the Pacific States (i.e., California, Oregon, and
Washington) over 650,000 tons of N were applied.

With such large amounts of N being applied, we as Soil Scientists
need to be concerned with the efficiency of applied fertilizer N.
We need to determine the amount of fertilizer N taken up by the
plant, the amount remaining in the soil after cropping and the
amount that is lost by processes such as volatilization, denitrifi-
cation and leaching.

In irrigated areas where excessive amounts of fertilizer N are being
applied, nitrate pollution of ground waters could pose a serious
problem. Therefore, we as Soil Scientists need to determine if
nitrate pollution of ground waters is the result of inefficient
fertilizer and management practices. This paper is a report of
current work in progress from a cooperative project between the
United States Bureau of Reclamation, Fresno, California, and the
University of Arizona, Tucson. This work is a part of a broader
investigation exploring the possibilities for the control of
nitrogen in drainage water by modified practices at the source.

Methods and Material

Fourteen lysimeters made of techite (fibre glass) pipe 15 inches in
diameter and 6.7 feet in length were filled with four major soil
types from the west side of the San Joaquin Valley of California.
Five columns were filled with Panoche fine sandy loam, a recent
alluvial, light textured, slightly saline soil and three columns
1 Research Soil Scientist, U.S. Bureau of Reclamation, Fresno,
California; Professor, and Assistant Professor, respectively,
Agricultural Chemistry and Soils, University of Arizona, Tucson;
Natural Resources Specialist; U.S. Bureau of Reclamation, Fresno,
California.
29
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were filled with Panoche clay loam. Three columns were filled with
Oxalis clay, a fine-textured soil, slightly to moderately compacted
in the subsoil, and moderately saline. Three columns were filled
with Lethent sandy clay loam, a basin-rim soil with a medium-
textured surface over a moderately compacted fine-textured subsoil
with moderate to strong concentrations of alkaline and saline salts.
These soils were developed from sediments of the Coast Range
Mountains. These lysimeters were located at Fresno at the Bureau
of Reclamation field laboratory.

The soils were screened, weighed, placed in the columns and tamped
to approximately field density.

The surface and subsurface soil material of the Panoche fine sandy
loam, and the Oxalis clay soils were mixed when the lysimeters were
filled. The soil material from the Panoche clay loam and the
Lethent soils were placed in layered horizons in the same sequence
as in the natural condition.

The lysimeters were instrumented with tensiometers, soil extract
suction probes, and soil moisture and temperature cells. These
instruments were placed in the soil columns by drilling holes
through the sides of the lysimeters and inserting the instruments
near the center of the soil columns. Generally four mercury-type
tensiometers were located in each lysimeter at approximately 18-,
30-, 42- and 54-inch depths. Three each of the soil extract
suction probes and the soil moisture and temperature cells were
installed at approximately 12-, 36- and 60-inch depths. A typical
layout of one lysimeter is shown in figure 1. When the lysimeters
were filled, sufficient water was applied to the columns to bring
the soils to field capacity and to start water draining from the
lysimeters. After the columns started to drain, water was added
in 4-inch increments every 2 weeks to leach the nitrates to a
relatively constant level.

Soil extracts were collected from the suction probes at varying
time periods, depending on the needs of the program, by applying
approximately 35 pounds of suction with a vacuum pump. The lysi-
meters were designed to allow the leachate from the soil column to
be collected at the bottom on the same schedule as the soil
extracts.

The volumnes extracted from the probes and collected in the
leachates were recorded. All of the samples were analyzed for
nitrates, electrical conductivity and pH. Some of the samples were
analyzed for chlorides, ammonia, total nitrogen and atom percent
excess ^N.
30
-------
Tensionmeter

Hg Surface
Suction Probes
a
Soil Moisture Cells
FIG, I- INSTRUMENT LAYOUT LYSIMETER N0.7
31
-------
The leaching program was continued until December 1968. At this
time the nitrate concentrations in most of the lysimeters, although
varying with soil type, were reduced to a fairly constant level.
Barley was planted in the lysimeters and three different types of
nitrogenous fertilizers were applied-- (NH^) 2^0/ and KNOo, fast
nitrogen release types and sulfur-coated urea, a slow nitrogen
release type. The fertilizers were applied at a rate equivalent
to 100 pounds N per acre or 1,250 .milligrams of N per lysimeter.
The (NH^^SO^ and the KNO^ fertilizers were enriched with approxi-
mately 10 percent "N and the urea with 28.2 percent "N. The
(NH^^SO^ was applied to two lysimeters filled with Panoche clay
loam and two filled with Oxalis clay. The KNOg was applied to two
soil columns of Panoche fine sandy loam and two of Lethent sandy
clay loam. Sulfur-coated urea was applied to two columns of
Panoche fine sandy loam. A control to which no fertilizers were
applied was maintained for each soil type. Samples from the
suction probes and the leachates were collected, frozen and sent
to the University of Arizona for analysis of nitrate and atom
percent excess N.

The barley was irrigated to approximately the rate that the farmers
of the area use in their normal field operations. The soils were
at field capacity when seeded and a total additional application
of water of 9.2 inches was applied during the growing season. The
irrigation water applied was obtained from a well at the University
of California Westside Field Station near Five Points. This water
contained approximately 2 milligrams per liter of NC>3 and 1,000
milligrams per liter of total dissolved solids.

After the barley was harvested in May the lysimeters were irrigated
with 8 inches of water. This amount brought the soils to field
capacity and sorghum was planted without additional fertilizers.
Total water application was 25.4 inches in addition to the 8-inch
preirrigation for the sorghum growing season. The sorghum was
harvested in October 1969.

Grain from the barley and sorghum crops was weighed and analyzed
separately from the straw or stover. All plant samples were dried,
ground, and analyzed for total nitrogen by standard micro-Kjeldahl
procedures. After titration, the ammonia was redistilled and atom
percent excess N determined.

Results and Discussion

The initial nitrate levels of the soils as determined from 1:1 water
extracts ranged from 55 in the Panoche clay loam subsoil to 500 in
the Lethent clay loam surface soil when the soils were brought from
the field. The nitrate levels in leachates collected during initial
32
-------
leaching and before fertilization ranged from 20,000 p.p.m. in the
Oxalis clay to 2,500 p.p.m. in the Panoche fine sandy loam. These
high levels are believed due primarily to the change in the environ-
ment of the soils as a result of the screening, mixing, and aera-
tion with the resultant increased microbial activity, ammonification
and nitrification of some of the native organic nitrogen. These
high nitrate levels also indicate how relatively low levels of
native nitrates can be concentrated in the ground water by leaching.

After the high initial nitrate concentration, a rapid drop in the
nitrate levels occurred as additional water was moved through the
columns. At this time the nitrate levels in the soil extracts from
all sampling depths of the soil columns had been reduced to less
than 10. The nitrates in the leachate of the several columns had
been stabilized at values ranging from about 50 in the Panoche fine
sandy loam to about 500 in the Oxalis clay. After the barley was
planted and the N enriched fertilizer applied, periodic samples
were collected of the soil extracts at three depths in the columns
and from the leachates. Data resulting from the analyses of these
samples, based primarily on the atom percent excess N, are pre-
sented in tables 1 through 7. These data are averages of values
from duplicate columns of each treatment.

Data for nitrogen content and the percentage which is attributable
to fertilizer -N in the "A" depths, 9 to 18 inches, are listed in
table 1. These data show that at this depth the highest percentage
of fertilizer -N appeared in those soils to which KNO^ was applied.
In Panoche fine sandy loam and Lethent sandy clay loam, respectively,
82 and 65 percent of the total nitrogen collected in the soil ex-
tract was fertilizer -N. By comparison, only 14 to 24 percent,
respectively, of the N in the extract was fertilizer -N when
(NH/)oSO/ and sulfur-coated urea were the N sources.

This would indicate that much of the NH/-N is tied up by the clay
complex of the soil near the soil surface. Since only 30 percent
of the sulfur-coated urea was readily soluble and the remainder
was treated to dissolve slowly, movement of nitrogen as urea could
be expected to be approximately 30 percent of N movement from KN03
assuming appreciable hydrolysis did not occur. The data are in
accord with these proportions. However, the system is complicated
by N release from sulfur-coated urea, hydrolysis of urea, nitrifi-
cation and soil textural differences; therefore, the apparent
proportionality may have resulted from compensating effects.
33
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Table 1 - Nitrogen Content and Percent of Fertilizer
Nitrogen in Soil Extracts from "A" Depths
December 16, 1968 - August 8, 1969
Soil Type
Fertilizer
Total N Fertilizer N

Panoche CL
Panoche FSL
Lethent CL
Panoche FSL
Oxalis C

(NH4)2S04

KN03
S:Urea-N
(NH4)2S04
In.
16
15
9
11
18
mg
12.6
49.2
34.1
15.2
16.2
%
14.2
81.7
65.0
23.7
14.07
The nitrogen content and the percent fertilizer nitrogen in the soil
extract at the "B" depths, 24 to 39 inches, are listed in table 2.
Table 2 - Nitrogen Content and Percent of Fertilizer
Nitrogen in Soil Extracts from "B" Depths
December 16, 1968 - August 8, 1969
Soil Type

Panoche CL
Panoche FSL
Lethent CL
Panoche FSL
Oxalis C
Fertilizer

(NH,) S04
KN03
KN03
S:Urea-N
(NH4)2S04
Depth
In.
39
39
24
33
31
Total N
mg
22.6
22.3
14.1
14.2
36.0
Fertilizer N
%
2.1
4.5
22.3
3.4
0.7
The percent of fertilizer -N of the total N collected in the B depth
was less than 4.5 with the exception of the Lethent clay loam. The
relatively high percentage of fertilizer N in the Lethent columns
was probably caused by the higher position of the suction probes in
the columns. These low values for the other columns indicate that
little movement of any of the fertilizers occurred to depths of
31 to 39 inches.

The nitrogen content and percent fertilizer N for the "C" depth are
listed in table 3. At the most 4 percent of the N collected from
the probe came from the applied fertilizer. The highest percentage
of fertilizer N was from the Lethent soil and least smallest was
from the Oxalis. These low values again indicate that a very small
percentage of the applied N moved through the soil columns.
34
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Table 3 - Nitrogen Content and Percent of Fertilizer
Nitrogen in Soil Extracts from "C" Depths
December 16, 1968 - August 8, 1969
Soil Type

Panoche CL
Panoche FSL
Lethent CL
Panoche FSL
Oxalis C
Fertilizer

(NH4) 2SO,
KN03
KN03
S:Urea-N
(NH4)2S04
Depth
In.
63
62
60
58
56
Total N
mg
25.1
39.3
19.7
19.0
20.0
Fertilizer N
%
1.6
2.1
4.2
1.2
0.9
The total nitrogen removed in the leachate and the percent of this
total that was fertilizer -N are listed in table 4. The total N
removed from the soil columns ranged from 156 to 442 milligrams;
however, of these amounts only 0.7 percent or less was from
fertilizer N.
Table 4 - Nitrogen Content and Percent Fertilizer N in the
Leachate - December 16, 1968 - August 1, 1969
Soil Type

Panoche CL
Panoche FSL
Lethent CL
Panoche FSL
Oxalis C
Fertilizer

(NH4) 2SO,
KNO^
KNC>3
S:Urea-N
(NH4) 2S04
Total N
mg
206
404
156
273
442
Fertilizer N
%
0.5
0.6
0.7
0.4
0.1
The total nitrogen removed from all soil extracts and leachates
and the percentage of these values that were fertilizer -N are
listed in table 5. Although the total N ranged from 224 milligrams
in the Lethent clay loam to 515 milligrams in the Panoche fine sandy
loam only a small percentage of these totals were from fertilizer -N.
The percentages of fertilizer N recovered varied from 0.6 percent
in the Oxalis clay to 12.5 percent in the Lethent clay loam. The
higher percentages of fertilizer -N recovered from those columns
using KN03 are due primarily to the large quantities extracted from
the "A" and "B" depths in these soils.
35
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Table 5 - Total Nitrogen Content of Soil Extracts,
Leachates and Percent Fertilizer N
December 13, 1968 - August 1, 1969

Soil Type

Panoche CL
Panoche FSL
Lethent CL
Panoche FSL
Oxalis C

Fertilizer

(NH ) S04
KN03
KNO
S:Urea-N
(NH4)2S04
Total N
(Soil + Fertilizer)
mg
266
515
224
321
515
Fertili zer
N
% of Total N
1.3
8.7
12.5
1.7
0.6
The fertilizer -N recovered as a percentage of the total fertilizer
applied is listed in table 6. The largest percentage, 3.58 of the
fertilizer -N recovered was from the Panoche fine sandy loam soil
treated with KNOo fertilizer. The smallest percentage, 0.26 or
3.3 milligrams, was from the Oxalis clay which was treated with
(NH ) SO . The most significant of these data are the amounts of
N recovered in the leachates. This is the quantity which under
field conditions would go into the ground water. The data show
that the largest percentage of fertilizer -N was recovered from
the leachate of the light-textured soil treated with KNO-}. It was
a very small amount, representing 0.23 percent or 2.9 milligrams,
of the total fertilizer applied. The least amount, 0.04 percent
or 0.5 milligrams was recovered from the heavy Oxalis clay soil
that was treated with
Table 6 - Recovery of Fertilizer N from all
Probes and Leachates
December 13, 1968 - August 1, 1969
Soil
Fertilizer Type
Sample Depth
A
% mg %
(NHu)2SOj,
KNO,
KNOj
S: Urea-
(NH,)2SO,
Pan.
Pan.
Let.
Pan.
Ox.
CL
FSL
CL
FSL
C
.14
3.21
1.81
0.30
0.19
1
40
22
3
2
.8
.1
.6
.8
.4
0.04
0.08
0.27
0.04
0.02
B
mg
.5
1.0
3.4
.5
.3

0
0
0
0
0
C
%
.03
.07
.07
.02
.01

mg
.4
.9
• 9
.3
.1

%
0.07
0.23
0.09
0.09
0.04
L
mg
• 9
2.9
l.l
l.l
.5
Total
%
.28
3.58
2.24
.45
.26
mg
3.6
44.8
28.0
5-7
3.3
The amounts of nitrate -N in leachates from various soil columns
treated with fertilizers and similar columns in which no fertilizers
were applied are listed in table 7.
36
-------
The amount of NOo-N removed varied in the fertilized columns from
910 milligrams in the Oxalis clay to 145 milligrams in the Panoche
clay loam and in the control columns from 788 milligrams in the
Oxalis clay to 133 milligrams in the Panoche clay loam. As noted
in table 6 the maximum amount of fertilizer -N recovered in the
leachate was 0.23 percent or 2.9 milligrams in the Panoche fine
sandy loam soil treated with KNO-. Lesser amounts of fertilizer
-N were recovered from the other columns. Although apparent
differences existed between the controls and the fertilized columns
(table 7) these differences probably were due to analytical and
soil variability rather than contributions from the applied
fertilizers.

The significance of these data showing relatively large amounts of
nitrogen removed from the columns is that only a very small per-
centage come from the applied fertilizers. Since the N in the
leachate did not originate from the fertilizer and the amount in
the applied water was small, it had to come from the native nitro-
gen in the soil.
Table 7 - Nitrate -N Recovered in the
Leachate of Soil Columns
December 16, 1968 - August 18, 1969
Soil Type
Fertilizer
Nitrate-N in Leachate
Control Fertilized
mg
Panoche CL
Panoche FSL
Lethent CL
Panoche FSL
Oxalis C
(NH,) 2S04
KN03
KN03
S:Urea-N
(NH4) 2S04
133
281
443
281
788
145
386
286
209
910
The percentages of applied fertilizer -N recovered by cropping are
listed in table 8. The highest percentage recovery by the barley
was 73 percent from the Panoche fine sandy loam treated with KNOo.
The lowest recovery, 47 percent, was from Panoche fine sandy loam
which was assumed to be due to the slow N release rate of the sulfur-
coated urea. The recovery rates in the other treatments ranged from
63 to 66 percent.

The percentage of recovery by grain sorghum of the applied fertil-
izer -N was greatest, 13.5 percent, in the Panoche fine sandy loam
treated with the sulfur-coated urea. The large recovery rate in
this treatment was due to the greater amount of residual N remaining
37
-------
in the soil as a result of the slow release of N from sulfur-coated
urea. The recovery rates in the other treatments ranged from 2.3
to 3.7 percent.
Table 8 - Recovery of Applied Fertilizer Nitrogen
in the Barley May 1969 and
Grain Sorghum October 1969

Fertilizer Soil Type Barley (% AFN) Grain Sorghum (% AFN)

/ MTJ . \ Q(~)
\ ivnjt / gQ "li
KNO,
KNO-j
Urea-S
(NH^SO,,

Panoche CL
Panoche FSL
Lethent CL
Panoche FSL
Oxalis C
: Straw
17.9
18.8
17.4
8-9
24.5
a rain
47.7
54.3
47.9
38.4
38.2
Total :
65.6
73.1
65.3
47.3
62.7
Straw
1.00
• 78
.76
3-75
1.60
Seed
1.87
2.89
1.51
9-78
1.45
Total
2.87
3.67
2.28
13.53
3.05
The percentages of the applied fertilizer -N recovered by barley,
grain sorghum and in the water samples collected between December 16,
1968 and August 8, 1969, are listed in table 9. They ranged from
a maximum 80.3 percent in Panoche fine sandy loam treated with KNOo
to a minimum of 61.3 percent in Panoche fine sandy loam treated
with sulfur-coated urea. The recovery from the other systems ranged
from 65.9 to 69.8 percent. The high percentage recovery from
Panoche fine sandy loam soil treated with KN03 was assumed to be
due to the N03-N form of fertilizer being more readily available
in the lighter-textured soil because of increased mobility in the
root-sorbing zone.

These data show that a minimum of 19.7 and a maximum of 38.7 percent
of the applied fertilizer -N in the various soil columns was unac-
counted for. The unaccounted-for portions are speculated to have
been the result of one or more of the following: (a) lost by
volatilization and denitrification, (b) t;Led up in the plant roots,
(c) adsorbed on the clay complex, (d) converted to an organic N
form by soil bacteria, and (e) remained in solution in the soil
columns.

A portion of the residual N could be leached from the columns at a
later date. To check this, water is still being applied to the
columns and the leachate collected; however, at this date no addi-
tional data are available.
38
-------
Table 9 - Recovery of Applied Fertilizer N in
Barley, Grain Sorghum, and Water Samples
Harvested December 1968 - October 1969

Fertilizer
(NH ) 2S04
KN03
KN03
S:Urea-N
(NH4) 2S04
Soil
Type
Panoche CL
Panoche FSL
Lethent CL
Panoche FSL
Oxalis C

Barley
%
65.6
73.0
65.3
47.3
62.1
Grain
Sorghum
%
2.87
3.67
2.28
13.53
3.05
Water
Samples
%
0.28
3.59
2.24
0.45
0.26

Total
7.
68.75
80.26
69.82
61.28
66.01
Summary

Relatively large quantities of N were removed in the leachatesj
however, less than 0.23 percent of this came from fertilizer -N.

Although all the quantities were small, the maximum fertilizer -N
recovered in the leachate was from the lighter-textured Panoche
fine sandy loam soil treated with KNO~. The minimum recovered was
from the heavy-textured Oxalis clay treated with (NH,)280, .

A larger fraction of the fertilizer -N was found at the lower depths
on the light-textured soils and on those soils treated with KNO^.
In the fine-textured soils little movement of the fertilizer N was
observed below the 30-inch depth.

During the period of this study, December 16, 1968, to approximately
October 1969, a maximum of 80.3 percent and a minimum of 61.3 percent
of the applied fertilizer -N was recovered from the soil columns by
the crops, soil extracts and leachates. The maximum amount was
recovered from Panoche fine sandy loam soil treated with KNO~ and
the minimum was recovered from the Panoche fine sandy loam treated
with the slow-release sulfur-coated urea.

Differences in the percentage of fertilizer -N recovered in the
leachate were small and apparently related to the type of ion in
which the nitrogen occurs rather than to fast or slow release
fertilizer.
39
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AGRICULTURAL NITRATE REDUCTION AT A WATER TABLE1
By
2
L. S. Willardson and Burl D. Meek
Introduction

The agricultural industry in the United States is responsible for
the application of 6 million tons of nitrogen fertilizer to the
soil every year. Fertilizer trials on research stations have indi-
cated that approximately 50 percent of the applied nitrogen can be
accounted for in the crop grown. The conclusion could be drawn
from this information that 3 million tons of nitrogen enters the
ground-water system of the United States annually from agricultural
sources. In 1966, however, 9 million tons of nitrogen were re-
moved from the soil by agricultural crops. This does not include
nitrogen removed from pasture and rangeland. With 6 million tons
applied and 9 million tons removed, agriculture would seem to be
responsible for annually mining 3 million tons of soil nitrogen.
The true disposition of nitrates applied as fertilizers is largely
unknown at the present time.

An experiment on the chemistry of ground water on an irrigated farm
in the Imperial Valley showed that ground water contains varying
amounts of nitrate depending on the depth of sampling. Nitrate
appeared in the soil solution above the water table but was
virtually absent below the water table. A laboratory study carried
out by Meek indicated that denitrification was taking place in the
soil solution near the water table.

Meek showed that by creating saturated soil conditions in the pres-
ence of bacteria and a source of energy such as organic carbon,
anaerobic conditions would develop in which reduction of nitrate
would take place. The bacteria decomposed the nitrate molecule to
obtain oxygen, liberating the nitrogen as nitrogen gas. This
process commonly occurs in saturated or nearly saturated soils.
1 Contribution of the Agricultural Research Service, Soil & Water
Conservation Research Division, Southwestern Irrigation Field
Station, Brawley, California.
2 Research Investigations Leader and Soil Chemist, Southwestern
Irrigation Field Station, P. 0. Box 1339, Brawley, California.
3 White, W. C. Plant Nutrient Toll. 1965 Harvest. USA Plant Food
Review, p. 16, Winter 1965.
4 Meek, B. D., L. B. Grass, and A. J. MacKenzie, Applied Nitrogen
Losses in Relation to Oxygen Status of Soil. Soil Sci. Soc. Proc.
Vol. 33, No. 4, July-August 1969.
41
-------
Research at the Southwestern Irrigation Field Station has indicated
this denitrification process can be managed in field soils to pre-
vent movement of agricultural nitrate into the ground water.

Soil Column Experiment

A special laboratory was constructed at the Southwestern Irrigation
Field Station to study the chemistry of water moving through a soil
profile toward a water table and then below the water table into
submerged drains. Six soil columns 15 inches in diameter and
10 feet deep were constructed such that drains could be placed at
6-, 8- and 10-foot depths with the controlled water table at 6 feet.
The columns were filled with a local soil profile in a disturbed
state but in the natural order. The soil columns were instrumented
with soil solution samplers, platinum electrodes for measuring
redox potential, porous cups for soil atmosphere samples, and
tensiometers for inferring soil moisture content. The effluent
from the drains was collected for analysis. Nitrate fertilizer at
a rate of 100 pounds of nitrogen per acre was applied in the first
irrigation water. Four irrigations were required to move the
nitrate concentration peak from the surface to the 6-foot water
table. Denitrification took place below the water table and in
the nearly saturated soil immediately above the water table.

Field Experiment

On the basis of results obtained on the Drainage Research Farm and
from the soil column study, an experiment was installed in the
field to test the concept of controlled denitrification by means
of submerged drains. The experiment is located on the farm of
John Nakamura near Firebaugh, California, on the west side of the
San Joaquin Valley. The soil profile is a Panoche silt loam surface
soil, a sandy loam horizon at 7.5 feet and a clay layer at approxi-
mately 9 feet. The clay layer appears a few miles to the north as
a surface soil. The Bureau of Reclamation and Soil Conservation
Service are cooperators with the Agricultural Research Service on
the project.

The experimental drainage system consists of a main collector line
8 inches in diameter and 1,850 feet long with 6 lateral lines
6 inches in diameter having a total length of 4,900 feet. The
drains were installed with a trenching machine. Washed concrete
sand envelope material was placed around the drains at a rate of
18 tons per 100 lineal feet. Concrete pipe with tongue and groove
joints in 2-foot lengths was used throughout. The drains were
installed 6, 7.5 and 9 feet deep. The main collector line was
installed at a depth of 11 feet at the drainage sump. A standpipe
was installed in the sump to control the field water table at the
42
-------
6-foot depth. This provided 0, 1.5, and 3 feet of submergence for
two drains at each depth. Water sampling tubes were installed in
the lateral lines at the time of installation. Sampling tubes
were placed inside the laterals near the outlet of each drain.
Approximately 200 feet from both ends of the lateral lines, solu-
tion samplers were installed in modified pipe sections to extract
water samples from eight positions around the exterior surface of
the drain. The purpose of these samplers was to obtain water that
had moved along various flow paths through the soil. Additional
soil solution samplers were installed in the soil at 4.5-, 6-,
7.5- and 9-foot depths at the tile line and at the one-third points
between drains. The 4.5-foot depth sampler was equipped with a
porous cup for obtaining water samples in the unsaturated zone
above the water table. A layout of the field is shown in figure 1.

Following installation of the drains, the field was irrigated to
consolidate the backfill in the trenches. After a smoothing opera-
tion, sorghum was planted. The crop was irrigated four times
during July and August of 1969. Water samples were collected from
the sampling system prior to and periodically following each irri-
gation. The water samples were analyzed for electrical conductivity,
dissolved oxygen, nitrate-nitrogen, organic carbon and pH. Iron
and manganese were present in very small amounts.

Results

The data from the soil column experiment are shown in figure 2.
The curves show the nitrate-nitrogen concentration in the profile
following successive irrigations. The peak nitrate-nitrogen con-
centration in the soil solution after application of an equivalent
of 100 pounds of nitrogen per acre as ammonium nitrate was 50 p.p.m.
As subsequent irrigations moved the concentration peak lower in the
profile, the nitrate-nitrogen content diminished. Safflower plants
were growing on the columns at the time. As the concentration peak
approached the water table and entered the capillary fringe, denitri-
fication occurred. Approximately 50 percent of the nitrate present
at the 5-foot depth was reduced in the 2one from 5 to 6 feet.

In the columns where the drains were submerged 2 and 4 feet, the
drain effluent had only 0.5 p.p.m. nitrate-nitrogen. There was
still some organic carbon in solution, indicating that additional
nitrate could have been removed.

Data from the soil solution samplers showed nitrate-nitrogen levels
in solution between the drains as high as 1,000 p.p.m. (figure 3).
The very high nitrogen contents were measured at the 7.5-foot
depth and were only slightly affected by irrigation. Nitrate-
nitrogen contents at the shallower depths were lower and were
decreased by irrigation.
43
-------
44
-------
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Figure 4 shows some of the nitrate data collected around three of
the drains before and after the third irrigation. The water table
was slightly above the 6-foot depth, allowing collection of a
saturation sample. Low nitrate concentrations occurred at the
tops of the 6-foot and 9-foot drains and varied following irri-
gation. Nitrate-nitrogen contents of the water around the 7.5-foot
drain remained relatively high. Water samples were taken inside
the drains at the same locations.

Electrical conductivities were measured on all water samples. High
conductivities were generally related to high nitrate contents but
there was not a strong correlation. Figure 5 shows the electrical
conductivities of the samples corresponding to the nitrate data
shown in figure 4. Conductivities decreased at the 6- and 7.5-foot
depths following irrigation but increased with time at the 9-foot
depth.

Organic carbon data are not shown but varied between 20 and 50
p.p.m. in the plot.

Discussion

The soil column experiment showed that denitrification can be
effected by establishing a water table above the drains, providing
a saturated flow path in which anaerobic conditions can develop.
The soil in the columns came from a cultivated field and the amount
of organic carbon in the soil solution from crop residues and
decaying roots was sufficient for denitrification. The soil in
the columns was relatively fine textured, resulting in a low perco-
lation rate. The crop growing in the columns undoubtedly extracted
part of the nitrate-nitrogen as the solution moved through the
profile. Important denitrification occurred in the capillary fringe
above the 6-foot depth even where the drain was not submerged.
Where proper conditions can be established, i.e., an oxygen shortage,
adequate organic carbon as an energy source, and a bacterial popu-
lation, anaerobic conditions will develop which will result in
denitrification.

The field experiment at Firebaugh illustrates the effect that a
lack of one of the denitrification components mentioned above can
have. The water collected in the samplers at the 7.5-foot depth
had a high nitrate content and 20 to 50 p.p.m. organic carbon.
The fact that the organic carbon was not taken down to a low level
indicates that suitable bacteria were not present or that the carbon
was in a form that could not be used. The general level of dissolved
oxygen in the same water was 1 to 2 p.p.m., which is higher than the
1-p.p.m. level present in the submerged zone of the laboratory
columns. The normal level of dissolved Oxygen in water from tile
drains is 4 to 6 p.p.m. If suitable bacteria were present, dis-
solved oxygen and organic carbon would be lower.
47
-------
48
-------
49
-------
Based on the results obtained in the columns, a nitrate-nitrogen
content of 500 p.p.m. in the ground water would require a surface
application of 1,000 pounds per acre of nitrogen as a nitrate
fertilizer in a single application. The farmer customarily applies
100 pounds of nitrogen as NHU during the season. The gross: dif-
ference in magnitude of nitrate contents indicates that the* native
ground waters are bringing nitrate to the area. The soils map for
the area shows a band of relatively light-textured soil running
upslope from the experiment location. The upslope area is arid to
semiarid and is a likely contributing source of natural nitrate
to the ground water. The contribution of agriculturally applied
nitrate appears to be minimal.

The high nitrate content of the ground water suggests the possi-
bility of dilution and use of the water as fertilizer. The
electrical conductivity is too high, however, and use of even the
diluted water as a fertilizer would result in salination of the
soil.

The intensive sampling program at the Firebaugh location has
emphasized the variability that can occur in such a field experiment.
The nonuniformity of ground-water quality flowing into the drainage
system is illustrated in figure 4. At the 6-foot depth on the day
before irrigation the highest measured nitrate-nitrogen content
outside the drain was 358 p.p.m. Ground water upstream from the
sampling point obviously has a much higher nitrate content. Samples
taken along the drains generally indicated a decrease in nitrate
content as the main collector line was approached. The drain at
the 9-foot depth before irrigation showed a nitrate-nitrogen content
of 414 p.p.m. At another sampling point downstream in the same
drain, the nitrate content decreased to 226 p.p.m. Denitrification
inside the drain is limited, so mixing with other waters in the
system is indicated. In some drains, the nitrate and conductivity
change in the same direction; in other drains, they change in
opposite directions.

The net result of the installation of the submerged drainage system
has been to decrease the nitrate-nitrogen content of the drainage
water. Figure 6 shows that for the final irrigation of the season,
conductivity of the drain effluent from the total plot remained
constant and the nitrate-nitrogen content decreased. If dilution
alone were responsible for the decreased nitrate level, the
electrical conductivity would also be lower.

It is doubtful that the submerged drains in the experiment will be
able to denitrify the native ground waters entering the system. By
dilution with the denitrified water from the irrigation, however,
the nitrate content of the drainage water will be reduced.
50
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Summary

Laboratory studies on large soil columns with a controlled water
table and submerged drains have shown that very low nitrate content
water can be delivered from agricultural drains. A field experi-
ment on drain submergence which intercepts ground water high in
native nitrate indicates that denitrified water from irrigated
agriculture can reduce nitrate concentrations in drainage water
by dilution.
52
-------
MONITORING NUTRIENTS AND PESTICIDES
IN SUBSURFACE AGRICULTURAL DRAINAGE

L. R. Glandon, Jr., and L. A. Beck
Introduction

The central valley of California is composed of two large valleys:
the Sacramento in the north and the larger San Joaquin Valley in
the south. The latter is approximately 300 miles long and 40 miles
wide and is characterized by several streams from the Sierra Nevada
and intermittent creeks from the Coastal Range. The San Joaquin
Valley is divided into two drainage basins: the San Joaquin Drainage
Basin which drains northward and empties into the eastern end of
San Francisco Bay, and the Tulare Lake Basin where waters are im-
pounded during years of excessive runoff.

San Joaquin Valley Drainage Investigation

The San Joaquin Valley Drainage Investigation was started in
1957.(1) The objectives were: (a) to define existing potential
drainage problem areas, (b) to define the quantity and quality of
drainage waters produced within these problem areas, and (c) to
develop a plan for disposing of these drainage waters without
creating problems in any of the surface or subsurface waters of the
San Joaquin Valley or the receiving waters to which the drainage
waters would be disposed. The quality portion of the investigation
was expanded in 1963 by initiating two pesticide monitoring programs;
intensified nutrient sampling started in 1966.

The purpose of this paper is to present data regarding the con-
centrations of nitrogen, phosphorus, and chlorinated hydrocarbon
pesticides observed in agricultural subsurface drainage from tiled
areas of the San Joaquin Valley in California.
1 Water Resources Technician; Chief, Quality and Treatment Unit,
California Department of Water Resources, Fresno, California,
respectively.
Parenthetical numbers refer to literature cited.
53
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UGEND
CENTRALX V
AREA S
^SOUTHERN
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Figure I. AREA OF INVESTIGATION
55
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area occupy only two physiographic positions. The soils are pre-
dominantly of the Tulare series. Agriculture in the southern area
is not as diversified as the central area and has proceeded with
reclamation of the lake bottom. Cotton, grain, and alfalfa are the
main crops; large acreages are still fallowed in the area. Well-
planned fertilizer programs are practiced by the larger farming
operations.

Physiographic Positions

Older Alluvial Fans. This physiographic position consists of older
alluvium resting at the higher elevations in which the soils are
medium textured and have moderately developed subsoils (developed
soils are soils which exhibit clay movement from the surface hori-
zon and clay accumulation in the lower horizon). These older fans
have developed from recent material in which the drainageways have
been entrenched so there is seldom any deposition of new material
on the surface. Weathering and soil development have caused the
formation of well-defined soil layers.

Recent Alluvial Fans. Recent alluvial fans occur at lower eleva-
tions than the older alluvial fans. Soils have been deposited
by recent flooding of intermittent streams from the older alluvium
and parent soils at higher elevations. They are derived from
outwash materials, mostly from sandstone and shale rocks and owe
their characteristics largely to the character of the stratified
parent material.

Basin. In this paper, basin and basin rim positions are included
under the general category of basin. The basin is the lowest
position elevationwise. Soils of the basin position are fine
textured with slightly compact to compact subsoils and stratified
at lower depths. Soils in basin positions are composed of colloidal
materials alluviated from soils and parent materials at higher
elevations.

Soils

In the northern area the soils in the recent alluvial fan positions
are mostly of the Sorrento soil series which have medium to fine-
textured surfaces and are highly stratified throughout the profile
resulting in lateral water movement in some areas. The older fan
position is dominated by Rincon soil series which is moderately
developed with restricted vertical drainage in the subsoil. The
Ambrose soil series is in the older position. The alluvium in this
area appears to be eroded from Pliocene, Pleistocene, and Quaternary
nonmarine formations.
57
-------
Recent alluvial fans in the central area are dominated by the
Panoche soil series which is highly stratified with silt, lime
seams, and coarse material, resulting in lateral movement in some
areas. The Panoche series is closely associated with the slightly
more developed Panhill. The older alluvium is represented by the
Lost Hills soil series which differs from the Panoche in having
distinct profile development. The recent and older alluvium soils
are derived from early Tertiary marine sediments of the coastal
mountains. These soils are by nature highly calcareous, contain
appreciable quantities of gypsum and are medium to fine textured
on the surface. The soils of the basin are clays and clay loams
which are predominantly from mixed granitic sources.

Most tile systems in the southern area are located in the basin
position. The soils are predominantly of the Tulare soil series,
a flat mass of fine alluvial material deposited by the Kings River.
Large areas of these poorly drained soils have been reclaimed.
These soils are derived mainly from igneous and sedimentary rock
sources. They contain decayed remnants of lake vegetation and
shell fragments of mollusks in the profiles and are calcareous
throughout.

Soils and geological data were obtained from the U.S. Department
of Agriculture Soil Conservation Service soil maps.

Selection of Tile Drainage Systems

Several factors were considered important in the selection of tile
drainage systems for monitoring. A number of tile drainage systems
were selected within each of the tiled areas. Larger systems
capable of reflecting the flows and concentrations from large
blocks of similar soils were preferred over smaller ones. Systems
were selected from various physiographic positions and as many
different soils as were available. Systems having a large number
of rather closely spaced laterals were chosen instead of single-
line type drains. Only tile drainage systems underlying fields
having active irrigation and fertilization programs were selected.

Tile Drainage Systems

Figure 2 is a representation of a typical tile drainage system.
Drains are buried 7 to 9 feet below the surface of the field and
surrounded with a sand or gravel envelope. The drains either have
open joints or are perforated. Flow within the drain is directed
to a collector line at the edge of the field and then to a concrete
reservoir, or sump, where it is then pumped into an open drain.
58
-------
LLJ
-------
Tile systems are generally of two basic designs: (a) the interceptor
type, a single line drain placed on the periphery of a field to
intercept or reduce lateral movement of water; and (b) the relief
type, having multiple laterals designed to alleviate existing high-
water table conditions within a field.

Tile systems of the central area are mostly of the relief type with
spacings that generally range from 200 to 600 feet. Northern tile
systems are mostly of the interceptor type; laterals are added if
a need arises. Tile drainage systems in the southern area consist
of both types mentioned above.

Sampling

Flow rates and nutrient concentrations were initially determined
hourly, daily, twice a week, and weekly until a reliable sampling
frequency was determined. Only minor fluctuations of nutrient
levels were observed for the different sampling frequencies;
therefore, a schedule of weekly sampling was determined satisfactory
for this investigation. Pesticide samples were collected quarterly
from the three drainage areas. Precautions were exercised to
minimize contamination. Soil samples were collected at depth
increments of about 1 foot.

Analyses

Nitrate determinations were made using a cadmium reduction technique.
The accuracy of this technique was determined to be adequate for
this study through the use of standardization curves and redundant
testing of 10 percent of the samples with the brucine technique.
Nitrate analyses of soils were made on soil extracts, suction
filtered from a saturated paste. Soils were extracted and refrig-
erated to minimize denitrification. A modified stannous chloride
method was used for phosphate analyses. Electrical conductivities
were determined with a conductivity bridge. Pesticide samples were
analyzed using a microcoulometric gas chromatograph technique.

Calculations

Nitrate and phosphate values were converted to pounds of nitrate
nitrogen and phosphate phosphorus per day, weighted by the average
weekly flow, and summarized to give average values per system per
month. These values were in turn summarized for different physio-
graphic positions and soil series. Summaries of average flows and
concentrations in the tables are weighted average values for the
2-year period.
60
-------
Chlorinated hydrocarbon pesticide maximum, minimum, and average
values were determined as well as the percentage of times detected.
Average values were calculated assuming a zero concentration for
samples in which no chldrinated hydrocarbons were detected.
Averages were also calculated for only the samples in which chlori-
nated hydrocarbons were detected.

Nitrogen concentrations from 3- to 10-foot depths were averaged
for purposes of soil profile analysis in this report.

Agricultural practices data were obtained from farmers and operators
on fields which had the tile drainage systems that were sampled.
The crop pattern and pesticide and fertilization data were obtained
for a 10-year period (1958-1968).

Results of Drainage Monitoring Program

Wide variations were observed in tile drainage discharge and nutrient
concentrations between the various systems monitored for any given
time of year. The total annual discharge from individual systems
ranged from a low of 0.3 to a high of 17.0 acre-feet per acre per
year; average nitrogen and phosphorus concentrations ranged from
2 to 400 mg/1 and 0.01 to 4.0 mg/1, respectively.

Seasonal variations of discharge were observed in all individual
tile drainage systems monitored. Flows were the highest during the
summer months (April-September) and decreased following a suspension
of irrigation. Minor seasonal variations of nutrient concentrations
were observed in drainage from all individual tile systems studied.
Nitrogen concentrations in tile drainage from several rice fields
declined rapidly during flooding and increased when the fields were
drained. In tile drains sampled since 1959, annual average nitrogen
concentrations have not declined.

Great differences in flows and nutrient concentrations were observed
between some areas. The highest discharge rates were observed in
the northern area where flows ranged from 0.05 to 0.03 acre-feet
per acre per month during the summer season and averaged 1.8 acre-
feet per acre per year for the 2 years investigated.

Nutrient concentrations were the highest in the central area where
average values in the combined drainage ranged from 22 to 51 mg/1
with an annual average of 33 mg/1.

Tile drainage from the southern area had an average phosphorus con-
centration which was three times that of any other area investi-
gated. The overall average phosphate phosphorus of the southern
61
-------
area drainage was 0.68 mg/1 and ranged from 0.60 to 0.85 mg/1.
Seasonal variation of flows for the different areas are illustrated
in figure 3; nutrient concentrations are presented in figures: 4
and 5.

Nitrogen concentrations also varied according to physiographic
positions and soil series. Nutrient concentrations in drainage
from older and recent alluvium of the central area was much higher
than drainage from similar physiographic positions in the other
two areas. The drainage from the basin position had the lowest
nitrogen concentrations. The total flow and average annual nutrient
concentrations for the systems monitored are summarized by area and
physiographic position in table 2.

It is evident from the data that tile drainage from certain soils
occupying alluvial fan positions contained substantially higher con-
centrations of nitrogen than did drainage from other soils situated
in similar positions in other areas. The highest concentrations
observed were in the drainage from the older and recent alluvium
of the central area, where 15 tile systems located in three allu-
vial soils ranged from 35 to 53 mg/1 and averaged 44 mg/1, which
was better than four times that in drainage from soils in fan
positions in the northern area. Table 3 shows the comparison of
nutrient concentrations in tile drainage from all of the alluvial
soils in the areas studied.

Soil Nitrogen Investigations

Certain alluvial soils of the west side of the San Joaquin Valley
contain high concentrations of nitrogen in the subsoil. This
phenomenon was first reported by Dyer (3) whose data showed that
nitrogen concentrations exceeded 1,400 mg/1 in Panoche soils down
to 50 feet. Doneen (4, 5) also observed high nitrogen concentrations
in shallow ground water in irrigated west side soils and in the
profiles of virgin sites. These observations of higher than normal
nitrogen values in the above investigations were responsible for a
program to define areas of residual nitrogen and correlate the
findings to those in tile drainage.

Soil profiles representing different soil series and physiographic
positions were sampled in an area extending from Tracy south along
the west side to Wasco. Forty-four sites were augered to a depth
of 10 feet or more and samples were collected at 1-1/2-foot incre-
ments for nitrogen analysis. Virgin or unirrigated sites were
sought to obtain the status of the quantity of the nitrogen :Ln the
soil before irrigation. Several dry farmed and irrigated sites were
also sampled.
62
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Figure 5 - SEASONAL VARIATION OF PHOSPHOROUS CONCENTRATIONS
FROM THE NORTH, CENTRAL AND SOUTHERN AREAS
64
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Results of Soil Nitrogen Investigations

Older Alluvium Position Soils. Five profiles were sampled in the
older alluvial fan position; these were of the Lost Hills series
and were virgin sites. Nitrogen concentrations in the soil extracts
ranged from 2 to 195 mg/1.

Recent Alluvial Position Soils. In the more recent alluvium six
profiles of Panhill soils had nitrate concentrations ranging from
13 to 164 mg/1. All of the soils were virgin with the exception
of one dry-farmed site. One soil which was low in nitrogen,
13 mg/1, was located in a well-drained area which suggests that
leaching took place. The highest nitrogen values were observed
at three Panoche sites which ranged from 32 to 231 mg/1. Two
profiles of Sorrento were examined; one was dry farmed and the
other virgin; concentrations were 17 and 25 mg/1 respectively.
Rincon soils were examined at two sites; one site averaged 3 mg/1
and the other 13 mg/1. One profile of Ambrose was analyzed at
41 mg/1.

Twelve profiles of Panoche soils were investigated in irrigated
areas to determine the effects of leaching upon the nitrogen in the
soil. These sites were sampled by groups in different farmed areas
along the west side. Seven profiles ranged from 7 to 16 mg/1;
three profiles showed slightly higher concentrations, from 18 to
36 mg/1. Five of the sites were located within the interfan areas
and ranged from 9 to 92 mg/1. Some of the soils examined in the
interfan areas were on the average four times higher than those in
the direct course of the depositing stream.

Basin Position Soils. Five virgin soils in the basin physiographic
position had nitrogen concentrations ranging from 1 to 13 mg/1.
Only two basin sites sampled were observed to have high nitrates
in the soil profiles. This was an atypical area of severely
restricted drainage where excessive salt had accumulated in the
soil profile from soils at higher elevations. Nitrogen concen-
trations in drainage from an experimental tile system located in
the same area ranged from 370 to better than 2,000 mg/1. This tile
system was not included in the monitoring program.

Effects of Agricultural Practices

Historic cropping data reflected some changes in agriculture but
were more important for determining trends in fertilization and
estimates of water use. No attempt was made in this report to
assess the amount of nitrogen contributed from crops or applied
water. Average irrigation applications in all study areas were
nearly the same according to records obtained from irrigation dis-
trict offices in 1967. Precipitation was higher in the northern area.
67
-------
Historically, the highest fertilization rates were recorded in the
central area. In a few individual cases the concentrations observed
in the tile drainage seemed to correlate with the amounts of ferti-
lizer applied. Fertilizer records were obtained over a lO^ear
period to correlate applied nitrogen to the concentrations observed
in the subsurface waters. Average fertilization for the major areas
investigated are given below, along with the nitrogen discharged in
the combined drainage.
Applied Fertilizer Discharged Nitrate
Area as Lbs of N/Ac as Nitrogen
1967 1957-1962
North
Central
South
72
92
43
51
75
68
1957-1967
42
88
74
Lbs/Ac Concentration mg/1
35
83
2
9
33
9
Amounts and concentrations of nitrogen in drainage from the central
area seemed to correlate with applied nitrogen fertilizer. However,
amounts not too different from that applied in the central area were
applied in the southern and northern areas at different times with no
observable effect on present concentrations.

Phosphate fertilizer was found to be applied sporadically in the
northern and central areas; records were not kept on most farms.
Records of its application were only obtained from one large opera-
tion in the southern area which indicated that phosphate fertilizer
was applied regularly at the rate of 50 pounds per acre every other
year.

Pesticides in Subsurface Agricultural Drainage

Over the years the greatest number of pesticide samples were col-
lected in the central area. This was the area where the greatest
number of pesticides were detected for the number of samples taken;
the highest maximum values were also reported in this area (2,800
p.p.t.). Drainage waters from the southern area contained the
highest average concentrations of chlorinated hydrocarbon pesti-
cides. A summary of chlorinated hydrocarbon concentrations in
agricultural drainage is presented in table 4. The averages of
all tile drains investigated show that the highest concentrations
occurred in 1963 and 1964 and declined each year until 1968, at
which time chlorinated hydrocarbons increased slightly. These
changes are shown in table 5. From 1963 through 1968, 371 samples
were collected from tile drainage systems of which chlorinated
hydrocarbons were detected 219 times or 59 percent of the total
samples collected. The most frequently detected CHC compound was
68
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DDD/DDT. Out of 452 total detections, it was detected 156 times
or approximately 34 percent of the time. Toxaphene was found in
greater concentrations than any other compound. A table showing
the most frequently detected CHC compounds and their maximum,
minimum, and average concentrations is given in table 6.
Records of acreages treated with various pesticides in Kern County
strongly indicate a decline of the usage of chlorinated hydro-
carbon pesticides and an increase in the use of organic phosphates
and carbamates. The percentage of total acres treated with CHC-type
insecticides generally decreased from 1948 to 1968. The inverse is
true of organic phosphates which increased steadily for the same
period. According to the data, the use of organic phosphates
surpassed CHC-type compounds in 1965. Trends in the usage of
synthetic insecticides within Kern County is illustrated in figure 6.

Farm advisors of other counties contacted by the Department of
Water Resources personnel reported decreased usage of CHC compounds
within their respective counties. Pesticide production records (6)
also correlate with the Kern County findings.

Discussion

Flows. Variable rates of discharge in tile drainage systems are
attributed mainly to irrigation. Flooded rice fields were a
striking example of irrigation influence; flows increased during
the summer months in all tile drains investigated. Soil strati-
graphy is a doubtless influence in most alluvial soils of the
west side; lateral water movement is common knowledge to most con-
servationists and drainage specialists. Two tile drains in the
northern area obviously discharged more water than was applied;
flows from these systems coincide with measurements and reported
flows of other known drainage systems not included in the study.
Vast areas of stratified alluvium along the west side have been
classified by the Soil Conservation Service (7) as having soil
horizons where the horizontal exceeds the vertical hydraulic con-
ductivity. Also, old meandering streamways long since obliterated
by man's activity form an inextricable network of natural aquifers
in the recent alluvial fans which "pinch off" as they approach the
basin soils.

Nutrients in Tile Drainage. Nitrogen in tile drainage was found to
be more closely associated with the physiographic positions than
agricultural practices. Several meaningful relationships were
established between the amount of nitrogen found in the soil profiles
and that discharged in similar soils by tile drainage systems.
71
-------
TABLE 6

CONCENTRATIONS OF MOST FREQUENTLY DETECTED
CHLORINATED HYDROCARBON PESTICIDES IN AGRICULTURAL
SUBSURFACE DRAINS IN THE SAN JOAQUIN VALLEY
(1963-1968)
CHC Compound
DDD/DDT
Dieldrin
Toxaphene
DDE
Heptachlor Epoxide
Lindane
BHC
: Times
: Detected
156
82
W
in
39
36
28
: Maximum :
Minimum
Averages _,_
: (ppt) : (ppt) : 0-valuesV : Det-values£/
600
142
950
130
45
340
1500
0
0
0
0
0
0
0
22
6
kk
2
1
3
6
53
28
369
20
13
26
81
I/ Average values include 0 values when chlorinated hydrocarbons were not-
~ detected.

2/ Average values include only the detected chlorinated hydrocarbons.
72
-------
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iu Z
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UJ
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73
-------
Nitrogen concentrations varied greatly between individual tile
drainage systems, depending upon the physiographic position and
soil series in which the tile systems were located.

Soils of Alluvial Fan Positions. Great differences in nitrogen
concentrations were observed in the combined drainage from alluvial
soils in different study areas. Tile drainage in the northern area
was, according to the data, four times lower in nitrogen than the
alluvial soils of the central area. These vast differences were
attributed to high residual nitrates in central area alluvial soils.

Tile systems associated with Panoche, Panhill, and Lost Hills soil
series had high nitrogen concentrations in the tile drainage which
correlated with the average concentrations found in virgin tile
zones of the same soil series located higher on the alluvial fans.
These high levels of residual nitrogen can possibly be attributed
to nitrate-bearing parent material in the general area which con-
sists mainly of sandstones and shales from sedimentary marine
formations of the coastal range. Sorrento and Rincon soils., which
according to the data are much lower in residual nitrogen, are
derived from mixed marine and nonmarine sediments.

Profiles of irrigated alluvial soils in the central area contained
lower levels of nitrogen than the virgin sites and the nitrogen
concentrations varied considerably from place to place. Pierce,
et al. (8), showed variable concentrations within a tile-drained
field of the Panoche series in the study area. Variable concen-
trations in the soil profiles between irrigated areas are attributed
to different leaching patterns associated with variable textures.
Soil profiles sampled in the interfan areas were on the average
four times higher in nitrogen than those in the direct course of
the depositing stream. In general, the finer-textured alluvial
profiles in the irrigated areas contain higher concentrations of
nitrogen in the soil than coarser-textured soils.

Soils of the Basin Position. Lower concentrations of nitrogen were
observed in drainage from tile systems located in basin and basin
rim positions which correlated with the low values found in soil
profiles. Average nitrogen concentrations in tile drainage ranged
from 4 to 20 mg/1 which correlated closely with the 1 to 13 mg/1 in
the soil tile zone. Field investigations conducted by the Federal
Water Pollution Control Administration (8) in an area of oxalis
soil (basin rim position) showed that nitrogen in soil moisture
extracted at 1-foot intervals to a depth of 4 feet was on the average
lower than that of three alluvial soils investigated. Tile drainage
from the same field correlated very closely with the values
observed in the soil profiles.
74
-------
The causes of low concentrations of nitrogen in drainage from basin
soils is unknown; however, vertical movement of surface water is
restricted by the clay and clay loam profiles allowing better plant
usage of nitrogen after fertilization. Denitrification losses in
basin soils with high water table conditions are indicated by the
presence of low nitrates in the subsoil and tile drainage waters of
heavily fertilized fields.

Ponnamperuma (9) reports that after fertilization no more than 3
milligrams per liter had ever been reported in submerged soils, and
that denitrification losses were offset by the use of ammonia type
fertilizers. He concludes that nitrate is not a suitable ferti-
lizer for rice because of denitrification and leaching processes.
Power (10) reports bacterial denitrification losses may account for
a major part of fertilizer nitrogen applied in lands with poor
drainage. His beliefs are supported by Woldendorp (11) who reports
that rapid denitrification occurs in well-drained soils during
periods of intense root activity such as under a grass sod.

Tile drainage from flooded rice fields in the Firebaugh area showed
decreases of nitrogen in some cases of less than one-third their
wintertime concentrations. One field in particular dropped from
63 mg/1 in January to 7 mg/1 for the months of May, June, and July.
Pierce, et al. (8), reports evidence of denitrification in Panoche
and Tulare loam soils studied in laboratory lysimeters.

Fertilization. Lysimeter investigations (12) have shown that nitro-
gen leached through soils is quite variable depending upon the
texture of the soil, the type of crop, and its maturity. Dyer, et
al. (3), showed evidence of nitrate leaching due to irrigation in
Panoche soils of the west side of the San Joaquin Valley; Johnston,
et al. (13), reported an average concentration of 25.1 mg/1 from
intensified investigations of four tile drainage systems near
Firebaugh, California. They also concluded that nitrogen and
phosphorus losses correlated with fertilizer application in the
fields investigated.

No direct correlations could be made between the applied fertilizer
and the concentration of nutrients in tile drainage during this
study. A general relationship appears to exist in the central area
where the heaviest fertilization occurred and the greatest amounts
of nitrogen were discharged; however, this was not considered
conclusive. Records from the southern area indicate that the basin
soils received greater quantities of phosphate type fertilizers in
comparison to the other areas which again seems to indicate a
relationship due to the fact that the highest phosphorus in tile
drainage was discharged from that area. There may be other factors
contributing to the complexity of the problem such as those observed
75
-------
during soil investigations (14) in the lakebed. Samples of soil
have shown there may be an association between shell fragments in
the soil of the Tulare soil series and the extraordinary phosphorus
content in the tile drainage. An analyses of shell fragments dis-
close 0.11 percent I^s ^y weight. Colormetric tests indicated
0.12 to 0.15 percent phosphate. Also, high water table conditions
in the area promote anaerobic conditions in the soil as evidenced
by the odor of H2S gas in freshly augered holes, which may cause a
release of phosphorus due to fluctuations in pH values.

Summary and Conclusions

Summary. Wide variations in flows and nutrient concentrations were
observed between individual drainage systems for any given time of
the year. Average concentrations of nitrogen and phosphorus ranged
from 2 to 400 mg/1 and 0.01 to 4.0 mg/1 respectively. Large
seasonal variations of tile drainage discharge were observed in
all areas and were attributed mainly to irrigation. Tile drainage
systems in the northern area discharged the greatest amounts of
effluent at 1.8 acre-feet per acre per year.

Nitrogen concentrations were the highest in combined drainage from
the central area; the average annual concentration was 33 mg/1;
seasonal variation ranged from 22 to 51 mg/1.

Higher than normal concentrations of phosphorus were observed in
the tile drainage from the southern area; the seasonal concen-
trations ranged from 0.60 to 0.85 and averaged 0.68 mg/1. However,
on the average, nitrogen concentrations in the area were low.

Comparison of tile drainage from different physiographic positions
showed that recent and older alluvial soils were higher in nitrogen
than basin soils. The average concentrations of composited drainage
from recent, older, and basin positions was 26, 15 and 10 mg/1
respectively.

Great differences were observed in drainage from different alluvial
soils in the area studied. Drainage from three alluvial soils,
Panoche, Panhill, and Lost Hills, average 44 mg/1 compared to
9 mg/1 for the alluvial soils in the northern area.

Average nitrogen concentrations within samples of virgin profiles
correlated very closely with tile drainage from tile-drained fields
of the same soil series. Fertilizer application was higher in the
central area; data show a slight increased usage of fertilizer
over a 10-year period. The quantity of nitrogen in tile drainage
seldom correlated with the amounts applied.
76
-------
Chlorinated hydrocarbon pesticide concentrations have decreased in
tile drainage from all areas investigated for the last 6 years.
The number of times chlorinated hydrocarbons were detected also
declined for the same period. Pesticide use records from Kern
County showed definite decreases in usage of chlorinated hydro-
carbons in favor of organic phosphates.

Conclusions

a. Variations in nitrogen concentrations of tile drainage
are more dependent upon the physiographic position and soil series
than all other factors.

b. High residual nitrates found in soils account for greater
quantities of nitrogen in tile drainage than that contributed by
fertilizers.

c. Decreasing concentrations of chlorinated hydrocarbon
pesticides in tile drainage is attributed to a decline in usage.
77
-------
Papers Cited

(1) California State Department of Water Resources, SAN JOAQUIN
VALLEY DRAINAGE INVESTIGATION, Preliminary Edition, Bulletin
No. 127, 1965.

(2) Harradine, F., SOILS OF WESTERN FRESNO COUNTY, CALIFORNIA,
University of California, College of Agriculture,
Agriculture Experiment Station, Berkeley, California, 1950.

(3) Dyer, Kenneth L., "INTERPRETATION OF CHLORIDE AND NITRATE
ION DISTRIBUTION PATTERNS IN ADJACENT IRRIGATED AND NON-
IRRIGATED PANOCHE SOILS," Proceedings Soil Science Society
of America, Vol. 29, No. 2; 1965.

(4) Doneen, L. D., "A STUDY OF NITRATE AND MINERAL CONSTITUENTS
FROM TILE DRAINAGE IN THE SAN JOAQUIN VALLEY, CALIFORNIA,"
A report prepared for the Federal Water Pollution Control
Administration, Pacific Southwest Region, San Francisco, 1966.

(5) Doneen, L. D., et al., "REPORT NO. 2 ON AGRICULTURAL DEVELOP-
MENT OF NEW LANDS, WEST SIDE OF THE SAN JOAQUIN VALLEY, LAND,
CROPS AND ECONOMICS," Department of Water Science and
Engineering, University of California, Davis, 1968.

(6) Anonymous, "PESTICIDES: PRESENT AND FUTURE," Chemical
Engineering, Vol. 76, No. 7, April 7, 1969.

(7) Miller, R. S. and Anderson, C. F., PROGRESS REPORT, FACTORS
AFFECTING DRAINAGE ON THE WEST SIDE OF THE SAN JOAQUIN VALLEY,
United States Department of Agriculture, Soil Conservation
Service, Berkeley, California, 1966.

(8) Pierce, W. H., Beck, L. A., and Glandon, L. R., "NUTRIENTS
IN AGRICULTURAL TILE DRAINAGE", Paper presented at Winter
Meeting of American Society of Agricultural Engineers, 1969.

(9) Ponnamperuma, F. N., "THE MINERAL NUTRITION OF THE RICE PLANT,"
Proceedings of a Symposium at the International Rice Research
Institute, 1964.

(10) Power, J. F., "WHAT HAPPENS TO FERTILIZER NITROGEN IN THE
SOIL," Journal of Soil and Water Conservation, 1968.

(11) Woldendorp, J. W., "THE INFLUENCE OF LIVING PLANTS ON DENITRI-
FICATION," Meded. Landb. Wagen. 1963.

(12) Allison, F. E., "THE ENIGMA OF SOIL NITROGEN BALANCE SHEETS,"
Advances in Agronomy, Vol. 7, 1955.
78
-------
(13) Johnston, W. F., Ittehadieh, F., Daum, R. F., and Pillsbury,
A. F., "NITROGEN AND PHOSPHORUS IN TILE DRAINAGE EFFLUENT,"
Proceedings Soil Science Society of America, Vol. 29, No. 3,
1965.

(14) California State Department of Water Resources, "EXTRA-
ORDINARY PHOSPHORUS CONTENT IN TILE DRAINAGE EFFLUENT FROM
TULARE LAKEBED SOILS," Unpublished Report, 1968.
79
-------
DESALINATION OF IRRIGATION RETURN WATERS

Bryan R. Sword
Introduction

Experiments were conducted from June 1967 to November 1968, on the
desalination of agricultural tile drainage waters at the Interagency
Agricultural Waste Water Treatment Center (IAWWTC) near Firebaugh,
California. These experiments were conducted by the Federal Water
Pollution Control Administration (FWPCA) in cooperation with the
Office of Saline Water (OSW). The purpose of the study was to deter-
mine the technical feasibility of desalination of irrigation return
waters. The units used were an Aerojet-General Reverse Osmosis
Water Purifier Model 1-560B-1 and an Ionics Electrodialysis
Demineralizer Model 300-B-3 (figures 1 and 2).

Water Quality

The water used in these studies was collected by a system of tile
drains servicing a 400-acre field. These waters, which have perco-
lated through 5 to 9 feet of soil, contained a total dissolved
solids (TDS) concentration of from 2,500 to 8,000 mg/1. The varia-
tion in TDS was seasonal with the lower concentrations occurring
during the summer growing season (June through September), when a
large quantity of irrigation waters is applied to the land. Con-
versely in the nongrowing seasons, when little irrigation is done,
the higher TDS concentrations prevail. Typical common ion analysis
for these two extremes are shown in table 1.

TDS Control

For the initial portion of the experimentation (June 1967 to January
1968) the desalination process was operated using the tile drainage
as it came from the fields. This, of course, gave an influent
which varied greatly over the test period. This variance compli-
cated data evaluation; therefore, a blending system was installed
in June 1968 to provide a constant 3,000 mg/1 TDS concentration.
Sanitary Engineer, San Joaquin Project, Federal Water Pollution
Control Administration, U. S. Department of the Interior, Fresno,
California.
81
-------
FIGURE I
oc.
LU
o:

a.
tu
-------
FIGURE 2

-------
CABLE
DESALINATION OF IRRIGATION RETURN WATERS
CHEMICAL ANALYSIS OF HIGH AND LOW VOLUME FLOWS

Calcium
Magnesium
Sodium
Potassium
Carbonate
Bicarbonate
Sulfate
Chloride
Nitrate
Boron
Iron (total)
pH*
TDS
Low Volume Flows
mq/1
363
178
1380
4.0
0
462
3480
474
83
14
0.03
8.3
6450
High Volume Flows
mq/1
172
91
706
3.
22
437
1520
254
23
6.
0.
8.
3020

9
10
6

* pH at time of analysis.
84
-------
Reverse Osmosis

Unit Description and Pretreatment. The Aerojet-General Reverse
Osmosis (RO) Unit Water Purifier Model 1-560B-1 has a plate and
frame design and contains 600 square feet of membrane. The water
flow schematic is shown in figure 3; the flow through the circular
desalination plates is shown in figure 4.

The pH of the influent was lowered from approximately 7.4 to a range
of 5.5 to 5.8 to control calcium carbonate precipitation and scaling.
A calcium sulfate precipitation inhibitor was also used. Cyanatner
P-35 manufactured by the American Cyanamid Company was used for
this purpose. It was injected at a rate of 3 mg/1.

Membrane Characteristics. Two RO membrane stacks were studied.
The first was a high pressure, low product yield, high salt re-
jection membrane. It was designed to have an applied pressure of
750 p.s.i.g. The second was designed to operate with a lower
applied pressure (350 p.s.i.g.) and higher product yield; but with
lower salt rejection characteristics.

Stack I. As shown in figure 5, the initial stack received an
influent with a varying TDS from June 1967 to January 1968. This
stack was subjected to the operational problems which occur during
the startup of any experimental operation. However, for the
initial 3 months it consistently produced a product containing
under 500 mg/1 of TDS, with an average salt rejection of over
90 percent (figures 6 and 7). A typical analysis for this per-
formance of the unit's influent, product, and brine stream is shown
in table 2. During the unit's operation, the product salinity
fluctuated as the influent salinity varied. This variation is
normal because of the increase in TDS concentration being passed
through the membrance by pore transport. However, the continued
decrease in product quality, as shown by figure 6, was due to
biological fouling and subsequent membrane deterioration.

The flux rate (figure 8) for this stack was as high as 13 gallons
per square foot of membrane per day. This occurred on the first day
of operation. It declined throughout the experimental period with
the exception of October 1967, when a higher than normally applied
pressure was used. The flux rate decrease was caused partially by
the increase in osmotic pressure due to the influent TDS increase.
However, the degree of flux drop that did occur is probable due in
part to another factor. It is speculated that with the high pressure
at which the stack was operated, a separation occurred between the
membrane and the spiral flow baffle (figure 4), thereby decreasing
the exposure time of the water to the membranes and thus resulting
in a lower flux rate. Table 3 summarizes the flux rates and salt
rejection for the operation of Stack I.
85
-------
FIGURE 3
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UJ CO

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UJ z

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8
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UJ

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FIGURE
t/O
CJ
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C_3
87
-------
FIGURE 5
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er
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1/Buj-SOnOS 03AHOSSia 1V101
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-------
FIGURE 6
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IS>

z 5
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i*£°
8^|0
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FIGURE 7
o
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2 <

It
—J —I
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at o
UJ
2
CO
II
J>
co£

Z < CO O
O (D O ,
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90
-------
TABLE
REVERSE OSMOSIS
Stack I
Mineral Analysis
Operating Conditions

Date of Sample - July 14, 1967
Operating Pressure, psig - 750
Temperature of Feed Water - 77°F
pH of Feed Water - 5.5
Ion
Ca++
Mg++
Na+
K+
B
S04=
HC03~
Cl"
NO3~
Fe (total)
SiO2
Total Alkalinity
Total Hardness
T.D.S.
pH*

Feed
230
111
862
3.4
8.2
2360
98
314
34
0.02
42
80
1030
4230
6.4
PPM
Product
3.3
1.7
82
0.0
6.1
28
16
94
29
0.02
13
13
15
304
5.4

Brine
347
215
1350
5.1
8.4
3720
140
440
37
0.02
58
136
1750
6400
6.5
* pH of samples at time of analysis,
91
-------
FIGURE 8
to

i <

5 Z UJ
Q £ <5

-------
TABI.E 3
REVERSE OSMOSIS
Stack I

Monthly Averages
Month
June
July
August
September
October
November
December
January
Flux
(qal/ft2/dav)
11.2
10.8
10.3
9.4
10.2
9.4
9.1
8.7
Salt
Rejection
(percent)
92
92
92
89
86
83
82
78
Feed
Salinity
(ppm)
5000
4300
3400
3900
6600
6650
6300
6000
Product
Recovery
(percent)
37
37
37
37
33
36
38
40
93
-------
Nitrate and boron removal rates are of particular interest. The
nitrate removal rate varied considerably having a range of 0 to 49
percent removal with an average of 27 percent. Boron removed had
a range of 8 to 35 percent removal with an average removal of 21
percent. Both ions were removed at a rate substantially lower than
the general IDS removal rate.

Stack II--Operation and Performance. The second stack was in opera-
tion less than 3 months. Although spared the startup problems the
previous stack experienced, an error in assembly shortened its life
considerably. This stack was operated with the TDS blending system-
previously described. It received a more consistent influent with
a TDS concentration of approximately 3,000 mg/1 (figure 9). The
unit's salt rejection remained constant at 85 percent with a product
TDS between 400 and 600 mg/1 (figure 10). Product flux, however,
as seen in figure 11, varied widely. The variations occurred with
constant operating conditions and were apparently independent of
any exterior operational changes. Upon disassembly of the sitack,
it was found that blockages had occurred in the brine flow paths on
the desalination plates. These blockages, the result of a corroded
aluminum washer, caused an increase in the differential pressure of
from 35 p.s.i.g. to above 95 p.s.i.g. through the stack. This
reduced the effective pressure by 20 percent, which directly influ-
enced the flux rate. It is also postulated that the effective
membrane area of the unit was reduced by bridging of the spiral flow
path with precipitated salt due to the closed brine stream. This
would, as in the case of Stack I, result in a reduced exposure of
the water to the membranes and again a decrease in product flux.

Due to the lower salt rejection design criteria of this stack, its
nitrate and boron removal was essentially zero. All analyses indi-
cated zero nitrate removal and a maximum boron removal of leiss than
0.5 percent. A typical influent, product, and brine stream analysis
for this stack is presented in table 4.

Cost Analysis. The power, chemicals, and supply costs for Sitack II
were summarized in an internal report to Office of Saline Water.
The power and supply costs for operating Stack II totaled $0.42 per
thousand gallons of product produced. A cost breakdown is shown
in table 5.

Electrodialysis

Unit Description and Operation. The electrodialysis unit (ED) was
operated in the summers of 1967 and 1968. A more consistent: opera-
tion was possible in 1968, and this report is concerned primarily
with that run. During this period, it was operated on essentially
the same blended water (figure 7) as the reverse osmosis unit. The
94
-------
FIGURES 9RIO
FEDERAL WATER POLLUTION CONTROL ADMINISTRATION
IAWWTC - FIREBAUGH, CALIFORNIA

REVERSE OSMOSIS DATA
TOTAL DISSOLVED SOLIDS VERSUS TIME
STACK H
o
V)
I-
Z Q
LU LJ
ID >
—
Q
tuuu
3000
S"

f
•ART JULY 9
JULY
^^^
^*
AUG
1968
INFLUENT

.
SEPT

OCT
FIGURE 9
PRODUCT
TOTAL DISSOLVED SOLIDS
PPM
l>0 * 00
o o ,„ o o
0 0^0 0
STACK H

\RT JULY 9
v_

JULY

^^^__

AUG
1968
PRODUCT

SEPT

OCT

FIGURE IO
95
-------
FIGURE II
00 h-
-------
TABLE 4
REVERSE OSMOSIS
Stack II
Mineral Analysis
Operating Conditions

Date of Sample - August 9, 1968
Operating Pressure, psig - 375
Temperature of Feed Water - 74°P
pH of Feed Water - 5.3
Ion
Ca++
Mg++
Na+
K+
B
SO4=
HCO3~
ci-
N03-
Fe (total)
Si02
Total Alkalinity
Total Hardness
T.D.S.
pH*

Feed
157
85
665
4.3
7.0
1650
55
320
22
0.05
30
46
742
2930
6.8
PPM
Product
2.5
1.2
140
1.0
7.0
6.9
21
196
24
0.02
17
17
11
381
6.8

Brine
331
161
1270
7.
7.
3480
79
400
20
0.
48
65
1490
5900
7.

0
3

0
* pH at time of sample analysis,
97
-------
TABLE 5

a
*

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CO H
S M
CO 0

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a

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cu cd 4-1
p* O 0
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VO 0^ 1^
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•CO- >
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H i-H O
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0
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rH
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^^
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CU
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•H
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4nuk
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CU 3
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1-1 1
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PCI
*
98
-------
Ionics Electrodialysi's Demineralizer Model 300-B-3 has 150 membrane
pairs and a product capacity of 25 g.p.m. The waste or brine stream
flow rate was varied to inhibit the precipitation of calcium sulfate.
The average rate was 8 g.p.m. for the experimental run. Calcium
carbonate precipitation was prevented by pH control of the brine
stream. A basic flow diagram of the unit is shown in figure 12.
An electro motive force (EMF) of 275 volts was applied across the
stack; current varied with water temperature, membrane conditions,
and influent TDS. The water was passed through the demineralizing
stack once, although the unit had the capability of recycling the
product water.

Performance. The percent TDS removal and effluent TDS concentrations
for the electrodialysis unit are shown in figures 13 and 14. The
apparent variations in TDS removal from 36 percent to less than
20 percent were highly dependent on the physical condition of the
membranes. In general, any sudden improvement in TDS removal was due
to a cleansing of the membranes. Typical substances which fre-
quently accumulated within the stack were precipitated salts, bio-
logical slimes, and suspended solids. The general decline in
efficiency from early August through September is attributed
partially to a 10°C. decline in influent water temperature and
partially to a general metal and/or biological fouling of the
membranes. Both of the above caused an increase in resistance
which lowered the TDS removal capacity of the unit.

Nitrate was removed with an average rate 1.98 times that calculated
for total dissolved solids. This factor compares favorably with
the removal range of values reported by Ionics, Incorporated, which
was 1.47 to 2.47 times the TDS removal (1) .

No significant boron removal was observed at any time, thus ruling
out the use of electrodialysis for reclaiming tile drainage for
direct reuse as irrigation water. A summary of common ion removal
rates is shown in table 6.

Cost Analysis. The cost for the operation of this unit based on
supplies, electrical power consumed, and an average product TDS of
2,300 mg/1 was $0.15 per thousand gallons of water treated. Pro-
rating this figure for a multistack unit and a product quality of
500 mg/1 TDS, the cost is comparable to the RO unit. Table 7 shows
the breakdown of operating costs for the electrodialysis unit.
2 Parenthetical numbers refer to literature cited.
99
-------
FIGURE 12
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100
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FIGURES I3SI4
FEDERAL WATER POLLUTION CONTROL ADMINISTRATION
IAWWTC - FIREBAUGH, CALIFORNIA
ELECTRODIALYSIS DATA
PER CENT REMOVAL OF TDS VERSUS TIME
JUN
JULY
AUG
SEPT
1968
FIGURE 13
TOTAL DISSOLVED SOLIDS VERSUS TIME
. DISSOLVED SOLIDS- mg/l X I03
— ro !>i
in en en

—

*-. v

^
JUN JULY AUG SEPT
1968
PRODUCT
101
-------
TABLE 6
ELECTRODIALYSIS DATA

RUN NO. 1
Date of Sample
Brine Stream Dilution — gpm
pH of Brine Stream
TDS Removal-percent
Temperature of Influent- °F
Applied E.M.F. -volts
Stack Current-amperes
July 15, 1968
8
5.9
35
75
276
13
Ion
Ca++
Mg++
Na+
K+
B
S04=
HCO3~
Cl"
NO3~
Fe (total)
SiO2
Total Hardness
T.D.S.
pH*

Feed
167
68
625
4.0
6.7
1430
336
167
26
0.00
29
696
3010
8.1
PPM
Product
105
51
515
2.5
6.5
1140
230
157
14
0.02
30
473
2240
7.9

Brine
321
138
1060
7.6
6.7
2580
147
593
54
0.02
29
1370
5240
7.6
* pH at time of analysis.
102
-------
ELECTRODIALYSIS DATA

Cost Analysis
TABLE 7
Item
Quantity
Used
Per Million Gallons
of Product
Cost
TOTAL
Cost Per
Million Gallons
of Product

Sulfuric Acid 1.04 Tons
Filter Cartridges 100
Electrical Power 4250 KWH

$31.
$ 0.
$ 0.
*
60 /Ton
79 /each
01/KWH

$32.86
$79.00
$42.50
$154.36
*Based on Tankcar lots.
103
-------
Summary

Desalination of San Joaquin Valley tile drainage water is techni-
cally feasible. The initial reverse osmosis stack was able to
achieve over 90 percent TDS removal; however, nitrate and boron
removals averaged less than 27 percent. The second stack removed
85 percent of the TDS with negligible nitrate and boron removals.

The electrodialysis unit had an average TDS removal of 23 percent
with a maximum of 36 percent. The cost for supplies and power for
reverse osmosis (Stack II) was $0.41 per thousand gallons of
product. The same costs for electrodialysis came to $0.15 per
thousand gallons of product, with a comparable cost to reverse
osmosis for a product of 500 mg/1 TDS.
104
-------
Papers Cited

(1) Katz, William E., NITRATE REMOVAL BY ELECTRODIALYSIS--A Brief
Review, Ionics, Incorporated, October 25, 1966.
105
-------
BACTERIAL DEVITRIFICATION OF
AGRICULTURAL TILE DRAINAGE

Thomas A. Tamblyn, Perry L. McCarty,
and Percy P. St. Amantl
Introduction

Man cannot continue degrading his environment. When he was a nomad
he did not have to worry about ecology. If he destroyed one area,
all that was necessary was to pick up and move on. As his culture
changed, he was no longer able to simply move away from the messes
he created, so he began sweeping the problem under the carpet. This
process of just covering up the problem has continued to the present
time. The country paid little attention to Teddy Roosevelt when he
told Congress on December 3, 1907, that:

"To waste, to destroy our natural resources, to skin-and
exhaust the land instead of using it so as to increase
its usefulness, will result in undermining in the days
of our children the very prosperity which we ought by
right to hand down to them amplified and developed."

However, for some unexplained reason, there is a change taking place.
The public is demanding a change in philosophy. This report is an
example of what is being done to satisfy this demand. It presents
the results of one of the many studies of advanced waste treatment
that have been undertaken in the past few years. The objectives
of the study were to determine if bacterial denitrification of
agricultural tile drainage was feasible under field conditions,
and if it was, to develop information on process costs.

Process Considerations

Bacterial denitrification is accomplished by both dissimilatory and
assimilatory means. Dissimilatory nitrate reduction is coupled to
energy metabolism. The nitrate ion acts as the terminal hydrogen
acceptor in the energy transport system. When an adequate concen-
tration of a degradable organic material is present, many facul-
tative bacteria are capable of bringing about dissimilatory nitrate
Sanitary Engineer, Federal Water Pollution Control Administration,
Fresno, California; Professor of Environmental Engineering,
Stanford University, Stanford, California; and Director, San
Joaquin Project, Federal Water Pollution Control Administration,
Ada, Oklahoma, respectively.
107
-------
reduction under anaerobic (or near anaerobic) conditions. Among
these are bacteria in the genera; Pseudomonus, Achromobacter. and
Bacillus. Assimilatory nitrate reduction is accomplished by
reduction of nitrate-nitrogen to the ammonia valence and the sub-
sequent incorporation of' the nitrogen into cellular material (1).

There are differences in the abilities of various bacteria t:o bring
about denitrification (2). Several bacteria can only reduce
nitrate to nitrite, while others can only reduce nitrite to molec-
ular nitrogen, while still others are capable of reducing both
nitrate and nitrite to molecular nitrogen. In addition, the
fraction of the total denitrification process attributable to
either dissimilatory or assimilatory reduction varies for different
organisms. However, these differences are masked and become insig-
nificant when working with mixed cultures, and the general equation
which follows can be formed for the process. McCarty, et al., have
presented the development elsewhere and it will not be given in this
paper (3).

Cm = (1.90 NQ + 1.18 Nx + 0.67 DQ) Cr (1)
Cm = requred concentration of degradable organic material,
mg/1.
NQ = nitrate-nitrogen concentration, mg/1.
N^ = nitrite-nitrogen concentration, mg/1.
Do = dissolved oxygen.
Cr = consumptive ratio.
Cr = actual organic carbon sources requirement
stoichiometric requirement for dissimilatory denitrifi-
cation and deoxygenation.

The consumptive ratio not only varies between organisms, it also
varies with the nature of the organic material being degraded and
possibly with the environment in which the degradation is taking
place (3), (4). Since tile drainage does not contain a significant
concentration of degradable organic material, chemical addition is
required for denitrification. Several organic compounds have been
screened to determine which compound should be used. Methanol was
picked for reasons of economics, a comparatively low consumptive
ratio, ease of handling, etc. (5).

Process Configurations

Once it has been determined that a biological process is technically
feasible, it is necessary to study possible process physical configu-
rations. These studies must be made to determine which is optimum
Parenthetical numbers refer to literature cited.
108
-------
for the problem at hand. There are three basic sanitary engineering
process configurations which could possibly be used for bacterial
denitrification: anaerobic activated sludge, anaerobic ponds, and
anaerobic filters.

Anaerobic activated sludge for the denitrification of municipal waste
has been studied under both laboratory and field conditions with and
without chemical additions (6, 7). Work is currently underway at
several locations to develop design criteria for this configuration
(8, 9). The anaerobic activated sludge process was not included as
part of the investigation reported on in this paper.

Studies of bacterial denitrification in completely mixed and partial-
ly mixed laboratory scale simulated anaerobic ponds have been made
(4, 5). Because of the long detention times (several days) required
for this process, it has been considered impractical for most situ-
ations. However, because of the low cost of construction and the
availability of land in the San Joaquin Valley, the decision was
made to include anaerobic ponds as part of this investigation.

In the anaerobic filters, the waste is passed through a flooded,
packed column-type reactor (a vessel containing an inactive medium).
A bacterial mass, that is similar to the zoogleal film in a
trickling filter, develops on the media, allowing the use of short
detention times without solids separation and recycle (10). Down-
flow anaerobic filters are and have been operated for bacterial
denitrification with methanol as the electron donor (11, 12).
Upflow anaerobic filters were operated for this investigation in
order to avoid duplication of effort and to fill a gap that existed
in the available information on anaerobic filters.

Experimental Procedures

The primary objective of this study (to determine if bacterial deni-
trification of agricultural tile drainage was feasible under field
conditions) required that the processes be tested under conditions
which duplicated, as nearly as possible, those to be encountered if
a full-scale plant were constructed. As a consequence of this, the
Interagency Agricultural Waste Water Treatment Center was constructed
near Firebaugh, California. It is located in one of the areas of the
San Joaquin Valley where there are existing drainage problems
(figure 1) . The climatic conditions and the quality of available
tile drainage (table 1) were nearly ideal for the investigation.

Anaerobic Ponds

The feasibility of bacterial denitrification in deep ponds under
field conditions was determined in 3-foot (0.9-m) diameter simulated
109
-------
FIGURE I
EXISTING AND POTENTIAL AGRICULTURAL WASTE WATER DISPOSAL PROBLEM AREAS
SAN JOAOUIN VALLEY-CALIFORNIA
SCALE OF MILES
110
-------
TABLE 1

CHARACTERISTICS OF TILE DRAINAGE USED AT THE INTERAGENCY
AGRICULTURAL WASTE WATER TREATMENT CENTER
Constituent i Range of Concentrations
. mg/1

Total Dissolved Solids 2500 - ?600

Salts

Sulfate 1500 - 3900

Sodium 620 - 2050

Chloride 310 - 6UO

Calcium l6o - 390

Magnesium 70 - 230

Bicarbonate 280 - 330

Potassium U - 11

Boron U - 15

Nutrients

Nitrogen 5-25

Phosphate 0.13 - 0-33

Pesticides < 0.001

Others

5-Day BOD 1-3

COD 10 - 20

DO 7-9
111
-------
deep ponds (13). Once the process was shown to be feasible, two
large ponds were constructed as shown schematically in figure 2.
The larger of the two ponds constructed at the Center is 200x50
feet (61 X 15-m) and has a floating cover. The smaller pond is
50x50 feet (15 X 15-m) and is not covered. Both ponds are approxi-
mately 15 feet (4.6-m) deep. To increase the solids retention
time, recycle is necessary. Through the parallel operation of
these two units, it was possible to evaluate the significance of
wind mixing and algal growth on process efficiency.

Anaerobic Filters

Figure 3 is a schematic diagram of the upflow anaerobic filters
used at the Center. Anaerobic filters with 6-foot bed depths which
were 4-, 18-, and 36-inch (10-, 46-, and 91-cm) diameter and 10x10
foot (3-m X 3-m) square have been used at the Center (14). The
lOxlO-foot filter has a false bottom (of the type used in water
treatment rapid sand filters) with an 8-inch (20-cm) plenum. The
primary purpose for building this filter was to investigate the
effect of scale-up on process efficiency due to changes in the
hydraulic regime.

Analytical Techniques and Sample Gathering

The routine analyses used to monitor the operation of the various
units at the Center are summarized below. Most samples were
normally collected between 8:00 and 9:00 a.m., and analyzed imme-
diately. Some samples were taken in the afternoon to gather
information on changes that may have occurred during the peak
photosynthetic period. Diurnal studies were also conducted, as the
need arose.
112
-------
FIGURE 2
(f)

-------
FIGURE 3
BIODEGRADABLE ORGANIC
CARBON INJECTION I
WASTE INFLUENT
GAS RELEASED TO ATMOSPHERE
I LI t HI II
TREATED EFFLUENT
MEDIA SUPPORT AND/OR
FLOW DISTRIBUTION SYSTEM
LEGEND
OPTIONAL SAMPLE TAPS
SCHEMATIC DIAGRAM
UPFLOW ANAEROBIC FILTER DENITRIFICATION PROCESS
114
-------
ROUTINE ANALYSES PERFORMED AT THE
INTERAGENCY AGRICULTURAL WASTE WATER TREATMENT CENTER
Analysis

Nitrate-Nitrogen

Nitrite-Nitrogen
Total Kjeldahl Nitrogen
Ammonia Nitrogen
Organic Nitrogen
Orthophosphate
PH
Alkalinity
Dissolved Oxygen
Suspended Solids
Volatile Suspended Solids
Optical Density
Electrical Conductivity
Algal Cell Counts and
Identifiers
Methanol
Technique

Brucine Method and/or Selective
Ion Electrode
Standard Methods, 12th Edition (15)
Kjeldahl Method
Distillation Method
Kjeldahl Method
Stannous Chloride Modification
Glass Electrode
Standard Methods, 12th Edition
Winkler Method
0.45 u Glass Paper, 103°C.
0.45 u Glass Paper, 600°C.
450 u, 5 cm Cell
Galvanic Cell
Sedgewick-Rafter Cell

Gas Chromatograph, Carbowax Column,
Flame lonization Detector
In addition to chemical analyses, several physical parameters were
monitored. Water temperatures were monitored daily with maximum-
minimum thermometers and periodically with 8-day recording thermo-
graphs. The influent pressure required for an anaerobic filter to
maintain a constant hydraulic detention time was monitored with
varying frequency throughout the study. Flows were calibrated
volumetrically. In addition, tracer studies using the chloride ion
as a tracer were run to determine the actual hydraulic regime of
the different units. Pre- and post-injection density corrections
were made using sodium sulfate. The tracer studies were analyzed
using the volume apportionment technique (16).

Results and Discussion

The initial field studies of bacterial denitrification in simulated
deep ponds indicated that significant denitrification could take
place in ponds with detention times as low as 5 days (13).

Data gathered from the large ponds, which started operation in the
fall of 1968, are summarized in table 2. The covered pond has
consistently outperformed the uncovered one. There are two primary
reasons for this. Large algal populations develop in uncovered
ponds and the resultant high dissolved oxygen concentration inhibits
115
-------
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denitrification. The second reason is that more of the influent
is short-circuited through the uncovered pond because of wind mixing
and temperature variations. The high nitrogen removal efficiencies
recorded for the uncovered pond, when operated with a 10-day detention
time, was probably caused by the formation of a natural partial cover.
The cover was composed of decayed algal and bacterial cells floating
on the surface of the pond. Some type of covering is necessary for
sufficient denitrification to take place. Research is currently
underway to determine if a floating vegetative mat may be used in
place of fabricated pond covers. There have been numerous mechanical
equipment breakdowns associated with these units; therefore, it is,
as yet, impossible to accurately predict the minimum detention time
possible. However, a 10-day detention time with 25 percent recycle
and a pond depth of 15 feet have been shown to be effective for
covered pond summertime operation (table 2) and these criteria were
used for developing process costs.

The data from experiments designed to investigate the significance
of anaerobic filter media size, texture, and sorptive quality are
summarized below (14).

NITROGEN REMOVAL EFFICIENCIES FOR
FILTER DENITRIFICATION UNITS CONTAINING VARIOUS MEDIA
Nitrogen Removal
Efficiency, Percent
Medium
Activated Carbon
Washed Sand
5/16" Coal
5/16" Volcanic Cinders
3/8" Aggregate
5/8" Volcanic Cinders
1" Coal
1" Volcanic Cinders
1" Aggregate
Min.

89
84
80
85
82
87
81
89
89
Max.

99
97
98
98
97
97
98
97
98
Average

96
93
93
94
94
91
93
96
94
Based on the results of an initial feasibility investigation, all
filters operated to generate this data had hydraulic detention
times (based on void volumes) of 2 hours. Medium surface texture,
size, and sorptive quality had no apparent effect on removal
efficiencies. After an extended period of continuous operation,
the bacterial mass within filters containing media with diameters
of less than 1 inch built up to the point where the required influ-
ent pressures (as high as 60 p.s.i.g.) rendered them uneconomical.
117
-------
The data gathered from the long-term operation of three filters
containing 1-inch-diameter media are summarized in the following
table:

SUMMARY OF LONG-TERM PERFORMANCE
OF FILTERS CONTAINING ONE-INCH-DIAMETER AGGREGATE

Detention Days Percent Nitrogen Required Influent
Time of Removal Pressure, psig
Hrs. Operation Min. Max. Average Min. Max. Average

0.5 275 40 91 68 3.5 11.8 7.2
1.0 240 64 97 88 3.2 9.6 5.4
2.0 244 79 97 91 3.5 9.7 6.2
For about the first 150 days of operation, the required influent
pressure fluctuated within a narrow range. There did not appear to
be any need for backwashing, etc. Since that time, an upward trend
has begun to appear. Investigations are currently underway to deter-
mine the best technique for reducing this pressure.

The temperature of the influent to the units varied from a high of
22° to a low of 10° Centigrade. There were some indications of a
relationship between temperature and nitrogen removal efficiency.
The units that were run with 0.5- and 1-hour detention were less
efficient during the colder part of the year than during the summer
months. This phenomenon did not hold true for the unit operating
at 2 hours. As the temperature of its influent dropped, the length
of the filter bed required for treatment increased. The 6-foot bed
depths used for this investigation and the range of temperatures
encountered were such that the effect was not reflected in the
overall treatment efficiencies of the unit. Process costs for
anaerobic filters were developed assuming a summer detention time
of 1-hour with a 6-foot bed of 1-inch-diameter aggregate.

The average consumptive ratio calculated from the data gathered at
the Center equals 1.47 mg/1 with a standard deviation of + 0.367.
The large standard deviation calculated for the consumptive ratio
is more likely due to inherent difficulties in field studies than
to fluctuations in system requirements. No difference could be
seen between pond and filter methanol requirements. With the
development of an automatic methanol control system, which would
respond to changes in influent and effluent quality, this variation
should be drastically reduced. The methanol requirement for a
typical influent containing 20 mg/1 of nitrate-nitrogen and 8 mg/1
of dissolved oxygen calculated by equation (1) equals 64 mg/1.
118
-------
As mentioned above, process costs have been estimated using the
operating criteria necessary during the warmer season of the year.
Computer simulation and an extensive water quality monitoring pro-
gram have yielded predictions of the seasonal variations that will
occur in the flow rate and nitrogen content of the waste requiring
treatment (17, 18). These predictions show that 70 percent of the
annual nitrogen load, in pounds per day, will arrive at the treat-
ment plant between April 1 and September 30 (the warmer season).
A bacterial denitrification plant designed to treat this load will
have more than adequate capacity for winter operation.

The estimated costs that have been made to date (December 1969)
indicate that treatment in either anaerobic ponds or filters will
most likely cost between $30 and $60 per million gallons of waste
treated. Plant designs for various influent rates are presently
being made. They will be used to develop equations for the
relationship of plant design capacity to costs per million gallons
of waste treated. From a comparison of the estimated range of
treatment costs and the conclusions of the Bay-Delta Report (19),
it can be said that agricultural tile drainage can be treated and
discharged to the San Francisco Bay System at less cost than that
of any alternative plan.

Conclusion

It has been shown that bacterial denitrification in covered
anaerobic ponds and anaerobic filters are both feasible under field
conditions. Additional work is needed on the actual costs of
treatment using the processes. However, preliminary estimates
indicate that agricultural tile drainage can be treated at a cost
that is substantially below the economic constraint that has been
placed on the system.
119
-------
Papers Cited

1. Schroeder, E. D., "DISSIMILATORY NITRATE REDUCTION BY MIXED
BACTERIAL POPULATIONS," a thesis submitted in partial fulfill-
ment of the requirements for the degree of Doctor of Philosophy,
Rice University, Austin, Texas (July 1968).

2. Alexander, M., SOIL MICROBIOLOGY, John Wiley, New York (1961).

3. McCarty, P. L., Beck, L. A., and St. Amant, P. P., "BIOLOGICAL
DENITRIFICATION OF WASTE WATERS BY ADDITION OF ORGANIC CARBON,"
24th Annual Purdue Industrial Waste Conference, Purdue
University, Lafayette, Indiana (May 1969).

4. Moore, S. F., "AN INVESTIGATION OF THE EFFECTS OF RESIDENCE
TIME ON ANAEROBIC BACTERIAL DENITRIFICATION," a thesis submitted
in partial fulfillment of the requirements for the degree of
Master of Science, University of California, Davis, California
(1969).

5. McCarty, P. L., "FEASIBILITY OF THE DENITRIFICATION PROCESS FOR
REMOVAL OF NITRATE-NITROGEN FROM AGRICULTURAL DRAINAGE WATERS,"
Appendix, California Department of Water Resources, Bulletin
No. 174-3 (May 1969).

6. Christiansen, C. W., Rex, E. H., Webster, W. M., and Virgil,
F. A., "REDUCTION OF NITRATE-NITROGEN BY MODIFIED ACTIVATED
SLUDGE," U.S. Atomic Energy Commission, TID-7517 (1956).

7. Ludzack, F. J., and Ettinger, M. B., "CONTROLLING OPERATION TO
MINIMIZE ACTIVATED SLUDGE EFFLUENT NITROGEN," Journal Water
Pollution Control Federation, Vol. 34 (1962).

8. Echelberger, W. F., and Tenney, M. W., "WASTE WATER TREATMENT
FOR COMPLETE NUTRIENT REMOVAL," Water and Sewage Works,
Vol. 116, No. 10 (October 1969).

9. Barth, E. F., Brenner, R. C., and Lewis, R. F., "CHEMICAL-
BIOLOGICAL CONTROL OF NITROGEN AND PHOSPHORUS IN WASTE WATER
EFFLUENT," Journal Water Pollution Control Federation, Vol. 40
(1968).

10. Young, J. C., and McCarty, P. L., "THE ANAEROBIC FILTER FOR
WASTE TREATMENT," Proceedings, 22nd Purdue Industrial Waste
Conference (1967).
120
-------
11. Parkhurst, J. D., Dryden, F. D., McDermott, G. N., and
English, J., "POMONA ACTIVATED CARBON PILOT PLANT," Journal
Water Pollution Control Federation, Vol. 39 (1967).

12. Smith, John; Federal Water Pollution Control Administration,
Robert Taft Center, Cincinnati, Ohio, Personal Communications
(November 10, 1969).

13. Brown, R. L., "FIELD EVALUATION OF ANAEROBIC DENITRIFICATION
IN SIMULATED DEEP PONDS," California Department of Water
Resources, Bulletin No. 174-3 (May 1969).

14. Tamblyn, T. A., and Sword, B. R., "THE ANAEROBIC FILTER FOR
THE DENITRIFICATION OF AGRICULTURAL SUBSURFACE DRAINAGE,"
24th Annual Purdue Industrial Waste Conference, Purdue University,
Lafayette, Indiana (May 1969).

15. "STANDARD METHODS FOR THE EXAMINATION OF WATER AND WASTE WATER,"
American Public Health Association, Inc., New York, New York,
12th Edition (1965).

16. Milbury, W. F., "A DEVELOPMENT AND EVALUATION OF A THEORETICAL
MODEL DESCRIBING THE EFFECTS OF HYDRAULIC REGIME IN CONTINUOUS
MICROBIAL SYSTEMS," a dissertation prepared in partial fulfill-
ment of the requirement for the degree of Doctor of Philosophy,
Northwestern University, Evanston, Illinois (1964).

17. Glandon, L. R., and Beck, L. A., "MONITORING NUTRIENTS AND
PESTICIDES IN SUBSURFACE AGRICULTURAL DRAINAGE," American
Geophysical Union, Fall National Meeting, San Francisco,
California (December 1969).

18. Lindholm, R. R., "SAN JOAQUIN VALLEY DRAINAGE INVESTIGATION-
SAN JOAQUIN MASTER DRAIN," California Department of Water
Resources, Bulletin No. 127, Preliminary Edition (January 1965).

19. "SAN FRANCISCO BAY-DELTA WATER QUALITY PROGRAM," Preliminary
Edition of Final Report by Kaiser Engineers, et al., to the
State of California (December 1968).
121
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ALGAL NUTRIENT RESPONSES
IN AGRICULTURAL WASTE WATER

James F. Arthur, Randall L. Brown,
Bruce A. Butterfield, and Joel C. Goldman^-
Introduction

In 1960, the Congress of the United States authorized the Bureau of
Reclamation, under Public Law 86-488, to construct a drainage dis-
posal facility for the Federal San Luis Service Area in the Central
San Joaquin Valley of California. That same year, the California
State Legislature, with voter ratification, passed the California
Water Resources Bond Act, which included a study of agricultural
waste-water drainage facilities in California.

The necessity for such legislation has arisen because of the in-
creasing demand for westside farmland, which though very rich in
nutrients, requires salt leaching to maintain a salt balance.
Unfortunately, the southern portion of the San Joaquin Valley is
almost a closed basin in which there is no natural drainage available
for removal of this waste water. Thus, the California Department
of Water Resources has estimated that by the year 2020, the annual
amount of brackish agricultural waste water requiring disposal will
be about 580,000 acre-feet per year.

The San Joaquin Valley Drainage Investigation (Lindholm, 1965),
which was initiated as a result of the 1960 enactment, concluded
that of several waste-water disposal plans proposed, three were most
likely to prove practical; namely, desalinization, evaporation, or
transportation (removal) of the water from the valley. Further
investigation indicated that the latter method would probably be the
most economical, and that if this method were selected for disposal,
the most convenient transportation route would be by way of a drain
running up the Central Valley through the Delta-San Francisco Bay
System and into the ocean. Unfortunately, this method of disposal
would mean discharging nitrogen into a water system already heavily
taxed with domestic and industrial waste (Beck and St. Amant, 1968;
Stetson and Price, 1968). To find ways of solving the potential
pollution problems that could arise in the Bay, the Interagency
Agricultural Waste Water Treatment Center (IAWWTC) at Firebaugh,
California, was established by a joint task force consisting of the
Research Aquatic Biologist, Federal Water Pollution Control Admin-
istration; Associate Water Quality Biologist, and Assistant Civil
Engineers, California Department of Water Resources, respectively;
Fresno, California.

123
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Bureau of Reclamation (USER), the California Department of Water
Resources (DWR), and the Federal Water Pollution Control Adminis-
tration (FWPCA), to study the economic and practical feasibility
of biologically removing nitrate-nitrogen from agricultural waste
water (Beck, Oswald, and Goldman, 1969).

After 1-1/2 years of actual prepilot operation, two biological
removal processes, anaerobic bacterial denitrification and algal
nutrient stripping, show the most promise as practical methods of
removing nitrate from eutrophicated waters (Beck and St. Amant,
1968; Beck, Oswald, and Goldman, 1969; St. Amant and McCarty, 1969;
Tamblyn and Sword, 1969). The algal stripping process is the sub-
ject of this paper.

The theory behind the algae stripping method of nitrogen removal is
simple; namely, any nutrient (e.g. nitrogen) required by algae can
be removed from the growth medium by assimilation and subsequent
conversion to cellular material. The algae, along with the: incorpo-
rated nutrient, can then be removed from the medium. Theoretically,
maximum nutrient assimilation by algae will occur if the nutrient
to be removed is the one limiting factor; however, in actual
practice this is often difficult to obtain.

In general, all algae can utilize inorganic nitrogen as either
ammonium salts or nitrates. The reduction process by which inor-
ganic nitrogen is utilized requires energy in the form of light
and is temperature dependent. The basic reaction by which nitrates
are reduced to ammonia generally is thought to occur in four stages
as follows:
nitrate nitrite hyponitrite hydroxylamine
reductase reductase reductase reductase
---- >> HN02 ----- > H2N202 ...... >> NH2OH - ..... -
2 (H) 2 (H) 2 (H) 2 (H)
The end product, ammonia, is then transferred to the amino acid pool
where it can be utilized in the formation of protein. The products
of nitrogen assimilation, which have been determined in Scenedesmus ,
the species studied at the IAWWTC, indicate an immediate increase in
cellular, soluble organic-N; followed by an increase in insioluble-N,
if sufficient carbohydrate is available (Lewin, 1967) .

In addition to seasonal changes in physical factors such as: light and
temperature, changes may occur in the nature and concentration of
nutrient constituents in the growth medium. These nutrient: changes
may limit physiological responses and mask the effects of other
environmental parameters. One such nutrient is phosphorus. It is
124
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one of the major nutrients required for normal algal growth and
normally comprises about 1 percent of the organic material of algae.
Changes in its availability can be brought about by shifts in pH
level, which leads to altering of the rate of phosphate uptake from
the medium, either by a direct effect on permeability of the cell
membrane, or by changing the ionic form of the phosphate, which in
turn can limit nitrate uptake. The latter effect of pH on phosphate
uptake appears to be the case at the IAWWTC, where high alkalinity
levels (300-400 mg/1 CaC03) along with increased pH (due to algal
assimilation of carbon as CO^) results in the precipitation of
phosphate salts. In addition, a reserve of available carbohydrates,
which is dependent upon carbon availability, also plays an impor-
tant role in phosphate uptake, since carbohydrate degredation by
oxidative phosphorylation is needed to provide energy for the
uptake process. Accordingly, when phosphate is deficient in the
growth medium, there is an accumulation of cellular fat, starch,
and wall substance, indicating an interference with nitrogen
metabolism (Lewin, 1967). Fluctuation in the amount of available
phosphorus can, thereby, affect algal growth and nitrate assimi-
lation altering the effect of other parameters being measured.

The availability of trace elements also affects growth and nitrogen
assimilation (Fogg, 1965). For example, as molybdenum becomes
deficient in the medium, the growth rate decreases. A lack of
iron, another essential trace element, leads to a decrease in
chlorophyll level which, in turn, limits the cells' photosynthetic
activity and, thence, its growth. Furthermore, iron (as well as
other metals required for growth) is only slightly soluble in well
oxygenated and/or basic water (Ruttner, 1965), and the availability
of such nutrients to algae in the precipitated form is dubious.
Unfortunately, these are the conditions typically found in high rate
algal ponds, since algae both produce oxygen and use CC>2 in the
photosynthetic process. This utilization of CO by actively growing
algae usually reached a point at which the C0£ revel in the growth
medium is not in equilibrium with the atmosphere, and the pH of
the medium, therefore, will rise. The pH increase, in turn, affects
the solubility and, hence, the availability of other nutrients. A
slowdown of growth results and, thus, the algae in effect limit
their own growth rate. The examples given in this and in the pre-
ceding paragraph are but a few of those which can be cited on how
different nutrient levels can affect algal growth.

The objectives of the IAWWTC are to develop an algal nutrient removal
system that is efficient, dependable, and economical. To accomplish
these goals, we are attempting to: (a) maximize algal nitrogen
assimilation by determining those factors, chemical and physical,
which can be rate-limiting, and (b) determine how to compensate for
fluctuations in those factors. Preliminary studies had indicated
125
-------
that detention time, depth, and mixing velocities would probably be
the most important parameters affecting the system. However, after
several months of operation, it became apparent that some other
variable was limiting nitrogen assimilation by the algae in the
outdoor growth units. As a result, it was decided to use light
box studies to define optimum algal growth and nitrogen assimilation
parameters before applying them to the outdoor growth units. This
paper presents some of the techniques and results obtained thus
far in the light box and outdoor growth studies.

Methods and Materials

Growth Media. Algal growth studies at the IAWWTC are conducted with
the use of cultures grown indoors in light boxes and in large out-
door growth units in which agricultural tile drainage water serves
as the basic growth medium (Lindholm, 1965). The chemical constit-
uents of this water, which is relatively high in total dissolved
solids (IDS), varies seasonally depending upon the irrigation and
fertilization practices for the particular crop grown.

Nutrient additives used in the light box studies were of analytical
grade. Nitrate-nitrogen (NaNO^) was added, when required, to the
test water to maintain a minimal nitrate-nitrogen concentration of
20.0 mg/1. This concentration is the average predicted for the
San Luis Drainage Area. Carbon additions were made by the injec-
tion of atmospheric air, bottled 4 percent, or 100 percent CC^
(passed through a water scrubber) directly into the flasks; or in
the case of the outdoor growth units, into the intake side of the
mixing pumps.

Growth Unit - Light Box. The light box at Firebaugh consists of
two shelves, 12x3 feet with lighting provided by eight 6-foot,
cool-white, fluorescent lamps placed 15 inches above the surface of
each shelf. Light intensities at the shelf level were approximately
350-400 feet-c. All ballasts were removed from the light fixtures
and placed several feet from the light b"ox to minimize temperature
increases. The studies were conducted with the use of continuous
light (Joint Industry/Government Task Force on Eutrophication, 1969).

Compressed air or bottled C0£ enriched air was passed through a
water scrubber for humidifieation, i.e., to reduce evaporation loss
in the culture containers. The various gas mixtures were distrib-
uted to the flasks through a central manifold system. The gas
pressure to each flask was equalized by placing a short capillary
tube in the air line between the manifold and the flasks.

Although temperature was not controlled to the desired degree
(23 + 1°C.), it remained within the 23 + 5°C range. The lack of
precise control did not appear to have any adverse effect on the algae.
126
-------
The use of 500 ml aliquots of medium contained in one-liter
Erlenmeyer flasks was found.to give maximum growth rates under
the experimental conditions used at the Agricultural Waste Water
Treatment Center (Brown and Arthur, 1969). Apparently, the
resulting surface to volume ratio allowed optimum CC^ exchange.
Cultures of this volume also permitted adequate subsampling for
chemical and biological analysis.

Outdoor Growth Units. Twenty 8x16x1.2-foot rectangular plywood
fiberglassed units, each having approximately 3,500 1 capacity, were
used for the outdoor growth studies. Two additional units were
used for depth studies, one 18 inches deep and the other 10 inches
deep. Detention time in all units was controlled by adjusting
the flow through rotometers and were calculated using influent flow
rates and pond volumes, not actual hydraulic flows within the units.
Mixing schedules were varied by the use of timers on each of the
mixing pumps.

In addition to the above growth facilities, the Center has one
large (1/4-acre) unit, 200x50 feet, capable of operating at water
depths of from 8 to 36 inches. As with the smaller outdoor units,
detention time and mixing cycles can be varied.

Inoculum. The predominant algal, species used as a test organism at
the Agricultural Waste Water Treatment Center has been the green
algae, Scenedesmus quadricauda, which was originally obtained from
the high-rate algal pond at the University of California's Richmond
Field Station, Richmond, California. This particular species was
chosen because: (a) it has a known high nitrate requirement, (b) it
was available in large quantities, (c) it was relatively easy to
separate, (d) it has been successfully used as a food supplement,
and (e) it occurs naturally in drainage canals near the IAWWTC,
although in relatively low numbers.

Inoculums of Scenedesmus quadricauda used in the light box nutrient
bioassay studies usually were from cultures in the log phase of
growth grown in the outdoor units. The cell density of the inocu-
lated sample was kept at about 2,000 cells/ml to minimize carryover
of nutrients. Although the cultures were neither axenic or even
unialgal, they were predominant (95-100 percent) Scenedesmus and
were acclimatized to the conditions prevailing at the particular time
of the year.

Analyses. Routine analyses of the growth medium used in the light
box and the outdoor growth units included analyses for nitrate,
nitrite, organic nitrogen, orthophosphate, alkalinity, and pH
(American Public Health Assocation, 1965). In addition, when specifi-
cally required, other chemical determinations were made (e.g., iron
127
-------
determinations, hardness, dissolved oxygen, general trace elements,
etc.).

Many of the conclusions reached in the present study were based on
nitrate uptake by the algae. Daily or semidaily nitrate-nitrogen
analysis was made with a specific ion electrode with random brucine
analyses used to establish a daity standard curve. Numerous com-
parisons of the electrode with the standard brucine method of
nitrate determination indicated that this method was much faster
than the brucine and subject to smaller variations.

Routine analysis of light box samples included suspended and volatile
solids, temperature, absorbence (on a spectrophotometer at: 410 mu),
cell counts, and algal species determinations. In addition to the
above, total light energy, electrical conductivity, IDS, air and
water temperature, wind and precipitation were recorded for the
outdoor growth units. As required, measurements were made of other
factors affecting the operation of algal growth units.

General Procedure. In order to eliminate as many variable's as
possible, a covered storage pond having an 820,000-gallon capacity
was used to provide a constant supply of water for use in the light
box and outdoor growth studies. This large reserve of water allowed
a study period of from 60 to 90 days, without significant changes in
influent quality, as well as making nutrient additions much simpler.
Because of the large fluctuations in nutrient levels betwe-.en studies
(figure 1) an algal nutrient bioassay was conducted in the light box
each time the storage pond was filled to determine the optimum
nutrient level required for maximum growth rate and nitrog;en assimi-
lation. This was normally accomplished by adding varying levels
of different nutrients to the tile drainage in a factorally designed
experiment (e.g., five levels of iron vs. five levels of phosphorus).
A plot of daily nitrate removal from the medium was then used to
determine the effect of the various nutrient additions on nitrate
assimilation. The optimum level of a particular nutrient or
nutrients was then tested to determine if the nitrogen uptake rate
could further be enhanced with the addition of other nutrients.
These tests usually were conducted at three CO? levels (swirled twice
per day, air, and 4 percent CO,,). If a particular nutrient was found
to be limiting nitrogen assimilation, it was added either to the
covered storage pond or to individual growth units.

Results and Discussion

The IAWWTC Site was chosen because: (a) the land was available
through the U.S. Bureau of Reclamation, (b) the tile drainage sump
had a large flow volume, and (c) the water had an average nitrogen
level which was close to the predicted average value for the drainage
128
-------
FIGURE
N390H1IN 31VM1IN
(I/BUI) sanos Q3Anossia ivioi
129
-------
area. In table 1 are shown the average predicted monthly flows,
nitrates, phosphates, and total dissolved solids expected in the
San Joaquin Valley agricultural waste-water drain. Note that: the
predicted average nitrate-nitrogen concentration will be about
20 mg/1.

Because of irrigation practices in the area of the IAWWTC over the
last 3 years, the major nutrient constituents have varied considerably
more, see figure 1, than is expected in the overall drain, which draws
from a large and varied service area. As a result, certain algal
growth characteristics were affected by nutrient variation, inasmuch
as the storage pond was filled during different times of the year.

To account for changes in growth patterns resulting from these
changes in water quality, we have been conducting routine algal
nutrient bioassays (in the light box) on our supply water to deter-
mine if any nutrient other than nitrogen is rate-limiting. Unfor-
tunately, the results of these studies have not always been applicable
to the outdoor growth units. For instance, in the light box cultures
there is a very definite year-round 2-4 mg/1 phosphate requirement,
as well as a 2-4 mg/1 iron requirement for part of the year. Figure 2
illustrates the typical relationship between iron and phosphate
additions on algal nitrate assimilation, as determined in the light
box cultures. Accordingly, during one 30-day study in the outdoor
growth units, iron was added to a series of ponds at different
detention times. Ponds receiving iron had total nitrogen removal
efficiencies 20 percent to 30 percent higher than did the ponds with
no iron additions (figure 3a). However, at other times of the year,
the addition of iron had little or no effect on nitrogen removal
(figure 3b), even though it did show up as rate-limiting under light
box conditions.

The same inconsistencies in response have been noted with phosphorus.
The addition of phosphate to the outdoor growth units (figures 4),
though not as well defined as in the light box cultures (figure 2),
clearly demonstrates a need for additional phosphate. During; certain
times of the year, particularly in late spring and early summer when
algal growth rates are maximum (optimum light and temperature), the
pH level is increased to as high as pH 10 and a noticeable precipi-
tation of phosphate salts occurs. In addition, if the level of
either iron or phosphate is increased over the optimum level of
both combined, the level of the other must also be increased. This
is probably the result of co-precipitation at the normal pH (8-10)
and temperature (20-30°C.) ranges of the studies (figure 2).

Temperature also has a significant influence on algal nutrient
response. As ambient temperatures decrease, algal growth rates
also decrease to a level where nutrients are not likely to be limiting
130
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FIGURE 2
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COPRE:CIPITATION
'OF FE: AND P
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P04-P ADDITION (MG/L)
AVERAGE N03 -N CONCENTRATIONS AFTER 12 DAYS
WITH VARIOUS P04 -P LEVELS AT TWO FE LEVELS

THE EFFECT OF IRON AND PHOSPHATE ADDITIONS ON NITRATE
ASSIMILATION IN THE LIGHT BOX
132
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THE EFFECT OF PHOSPHATE ADDITION ON NITRATE REMOVAL

IN OUTDOOR GROWTH UNITS
134
-------
(this is not the case with light box cultures). Figure 5 illustrates
the effect of temperature on total nitrogen removal in outdoor growth
units. In this particular study, a submergible heater was placed
in a small growth unit for a 30-day period. Water temperatures in
the unheated pond averaged 16.5°C., while the heated pond averaged
5°C. higher. Nitrogen removal rates were increased by as much as
20 percent in the heated unit over the unheated unit. The data
gathered suggest cause-effect relationship between temperature
and nutrient requirements, most likely due to the effects of temper-
ature on both chemical solubility and biological activity.

Figure 6 illustrates the effect of CC^ addition on algal nitrate
assimilation in the light box. Growth rates, along with corresponding
nitrogen uptake by algae, are greatly increased by the addition of
4 percent CC>2 or atmospheric air. Carbon dioxide performs two basic
functions in algal systems. First, it provides the carbon necessary
for cell synthesis (carbon is often a limiting nutrient in our
water); and, secondly, it maintains the pH at a level at which
nutrient precipitation (e.g., Fe and PO.) is decreased.

The advisability of using CC^ in laboratory studies of algal growth
requirements is often questioned as constituting an unnatural condi-
tion. However, the function of carbon is no different from that of
any other algal nutrient in that it should be in excess (unless it
is specifically being tested) when the effect of any other nutrient
is to be determined. Meyers (Lewin, 1967) states that the investi-
gator faces criticism if he uses 5 percent CC^ for aeration; yet,
if he does not aerate, the CCL concentration may be reduced to a
level below that commonly encountered in natural waters in which
cell concentrations are typically low and CO^ rarely is a limiting
factor. We have found (Brown and Arthur, 1969) that in our water,
when there are high algal concentrations, an external inorganic
carbon source (as CO^) acts primarily to speed up growth, rather
than to change the overall effect of supplemental nutrient addition.

When extra carbon was added as 100 percent CO during this past
summer (1969) to several of the smaller outdoor growth units (figure 7)
and the large, one-quarter acre pond for several hours each day,
there was an immediate increase in nitrate, nitrite, and phosphate
uptake; however, after 10 or 15 days of 100 percent nitrate removal,
an algal die-off occurred in the ponds. Subsequent light box and
growth unit studies have failed to reveal the cause. However,
light box studies conducted immediately after the algal growth pond
die-offs did indicate that neither the 100 percent C02 or the by-
products resulting from C02 addition were toxic. Nor did the die-
offs appear to be the result of nitrogen deficiency, as was first
suspected. Furthermore, a study involving the outdoor growth units
conducted in early fall (1969) showed little effect of C02 on nitrate
135
-------
FIGURE 5
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FIGURE 7
20-1
/•INJECTION OF C02
DAYS OF RUN
EFFECT OF C02 ADDITION ON EFFLUENT NITRATE, NITRITE, AND PHOSPHATE
IN SMALL OUTDOOR GROWTH UNITS
138
-------
uptake (figure 8), nor were there any subsequent algal die-offs.
Indications are that the dissimilarities noted between the light
box cultures and the growth units with respect to algal nutrient
responses were the result of different seasonal growth rates.

Summary

Studies presently being conducted 'at the IAWWTC to develop practical
biological methods for removing nitrogen from the proposed San Luis
Drain indicate that algal assimilation of nutrients into cellular
material with subsequent removal from the growth medium is a feasible
process. Furthermore, the efficiency of the proposed system is
greatly enhanced if as many variables as possible are optimized,
leaving only nitrogen limiting.

Earlier studies on the effect of such physical variables as deten-
tion time, mixing, and depth indicated that one or more other
factors were affecting algal growth and nitrogen assimilation.
Preliminary light box studies indicated that the variations which
occurred in the levels of nutrients in the source water may have
been responsible for differences in algal response. A review of
chemical data pertaining to the source water over a 3-year period
indicated that large fluctuations in major nutrients and total
dissolved solids did take place.

Laboratory algal nutrient bioassays indicate that orthophosphate
additions of 2.0-3.0 mg/1 P are required the year round to remove
20.0 mg/1 nitrate-nitrogen from the growth medium. This amount
corresponds to the theoretical values predicted from analyses of
the chemical constituents of typical algae. Algae usually contain
10 percent nitrogen, 1 percent phosphorus, and 50 percent carbon.
Iron and carbon (as CO^) also have been found to be limiting algal
growth and nitrogen assimilation during part of the year.

Application of light box results to outdoor growth units have not
always been successful. These differences are thought to be a
function of growth rate. In the light box bioassays, light and
temperature are optimum the year round, while in the outdoor growth
units these parameters vary and as growth rates vary nutrient
requirements vary. It is hoped that in the near future, it will be
possible to quantify these variations and to develop relationships
between them.
139
-------
FioURE 8
IOO-,
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EFFECT OF VARIOUS LEVELS OF AERATION ON NITROGEN REMOVAL

IN SMALL OUTDOOR GROWTH UNITS
140
-------
Papers Cited

(1) American Public Health Association, 1965. STANDARD METHODS
FOR THE EXAMINATION OF WATER AND WASTE WATER, 12th Edition,
American Public Health Association, Inc., New York, New York.

(2) Beck, L. A., and St. Amant, P. P., 1968. IS TREATMENT OF
AGRICULTURAL WASTE WATER POSSIBLE? 4th International Water
Quality Symposium, San Francisco, California (August 14, 1968).

(3) Beck, L. A., Oswald, W. J., and Goldman, J. C. 1969. NO,
REMOVAL FROM AGRICULTURAL TILE DRAINAGE BY PHOTOSYNTHETIC
SYSTEMS. Symposium on Sanitary Engineering Research Develop-
ment and Design, Cornell University, Ithaca, New York (1969).

(4) Brown, R. L., and Arthur, J. F., 1969. EFFECT OF SURFACE/
VOLUME RELATIONSHIPS, C02 ADDITION, AERATION, AND MIXING ON
NITRATE UTILIZATION BY SCENEDESMUS CULTURES IN SUBSURFACE
AGRICULTURAL WASTE WATER. Presented at the Eutrophication-
Biostimulation Workshop, Berkeley, California (June 19, 1969).

(5) Fogg, G. E., 1965. ALGAL CULTURES AND PHYTOPLANKTON ECOLOGY,
University of Wisconsin Press, Madison and Milwaukee.

(6) Joint Industry/Government Task Force on Eutrophication, 1969.
Provisional Algal Assay Procedure, unpublished.

(7) Lewin, R. A. (Editor), 1967. PHYSIOLOGY AND BIOCHEMISTRY OF
ALGAE, Academic Press, New York and London.

(8) Lindholm, R. R., 1965. SAN JOAQUIN VALLEY DRAINAGE INVESTI-
GATION—SAN JOAQUIN MASTER DRAIN, Preliminary Edition,
California Department of Water Resources, Bulletin No. 127.

(9) Ruttner, 1965. FUNDAMENTALS OF LIMNOLOGY, 3rd Edition,
University of Toronto Press.

(10) St. Amant, P. P., and McCarty, P. L., 1969. TREATMENT OF HIGH
NITRATE WATERS. Presented at the Annual Conference, American
Water Works Association, San Diego, California (May 1969).

(11) Stetson, C., and Price, E. P., 1968. A DRAINAGE SYSTEM FOR
THE SAN JOAQUIN VALLEY. 4th International Water Quality
Symposium, San Francisco, California (August 14, 1968).

(12) Tamblyn, T. A., and Sword, B. R., 1969. THE ANAEROBIC FILTER
FOR THE DENITRIFICATION OF AGRICULTURAL SUBSURFACE DRAINAGE.
24th Annual Purdue Industrial Waste Conference, Purdue
University, Lafayette, Indiana (May 8, 1969).
141
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THE EFFECTS OF NITROGEN REMOVAL ON
THE ALGAL GROWTH POTENTIAL OF
SAN JOAQUIN VALLEY AGRICULTURAL TILE DRAINAGE EFFLUENTS

Randall L. Brown, Richard C. Bain, Jr.,
and Milton G. Tunzi1
Introduction

An integral part of the Firebaugh treatment studies was laboratory
culture experiments to determine the effectiveness of the two
biological processes under investigation, algal stripping and
bacterial denitrification, for removing the algal growth potential
(AGP) of the tile drainage water when added to potential receiving
waters in the Sacramento-San Joaquin Delta. The AGP can be practi-
cally defined as the maximum algal growth (cell numbers, biomass,
etc.) occurring in a water sample in the laboratory when available
nutrients in the sample are the only limiting factors. An additional
objective of these studies was to determine if nitrogen, an essential
algal nutrient, was limiting in the Delta system during all seasons.
Earlier work by the FWPCA (1968) had concluded that nitrogen limited
algal growth only during the spring and summer.

This paper presents some results from these laboratory culture
studies conducted at laboratories in Alameda (FWPCA) and Bryte (DWR),
California during the period January through November 1969. General
procedures for batch assays follow the Provisional Algal Assay Pro-
cedure (1969) with changes in growth being measured by either in
vivo or extractable chlorophyll fluorescence (Bain, 1969). Fluoro-
metry methods were used because of the small subsample volumes
required for chlorophyll measurement and because of their simplicity,
rapidity, and sensitivity.

Methods and Materials

Water. Samples of Delta water were collected near Antioch the day
before an experiment and stored overnight in the dark in plastic
bottles. Treated and untreated tile drainage was also obtained from
the Firebaugh site the same day. Algae were removed from growth
Biologist, California Department of Water Resources, Fresno,
California, and Sanitary Engineer and Aquatic Biologist, Federal
Water Pollution Control Administration, Alameda, California,
respectively.
143
-------
pond effluent using a flocculent, usually alum or lime. This sepa-
ration process simulated conditions of an operating algae harvesting
plant. All samples from the Firebaugh site were filtered through
Whatman GFA glass filters to remove residual fluorescence. The
Delta samples were unfiltered and thus contained native phytoplankton
which was tested for growth response in the assay. Unfiltered Delta
water, usually containing 1,000-2,000 algal cells per millilLter
(predominantly diatoms), was mixed with various proportions of
treated and untreated agricultural drainage water. Algal counts of
representative flasks were obtained at the termination of an
experiment.

Environmental Conditions. Although both laboratories generally
followed culture procedures outlined in the Provisional Algal Assay
Procedure (1969), there were deviations because of preexisting
facilities and equipment. In each laboratory, growth chambers were
constructed in converted cold storage boxes with temperatures con-
trolled to 20°G.+ 1°C. Lighting was provided by cool-white fluores-
cent bulbs of 350-450 ft-c illumination. At Alameda, light was
directed from beneath the flasks; whereas, at Bryte the bulbs were
above the cultures. Lighting was continuous at both laboratories.
Bryte had reciprocating shakers and both laboratories had the facili-
ties for air mixing; however, only daily swirling was used in these
regrowth studies. Preliminary culture work indicated that swirling
was as effective as either shaking or air mixing. The cultures were
incubated in 500 ml Erlenmeyer flasks filled with 250-300 mis. of
sample. All cultures were grown in triplicate.

Measurement of Response. Both laboratories utilized Turner Model III
fluorometers to measure the in vivo changes in chlorophyll fluores-
cence. Modifications to the fluorometers included a red sensitive
photomultiplier and high sensitivity door (which passes light through
the sample more than once) at Bryte and blue light sources at both
laboratories. A blue primary filter (Corning CS 5-60 with maximum
transmission at 450 mu) and a red secondary filter (Corning CS 2-64,
maximum transmission at 650 mu) were used in the machines. Instru-
ments were nulled against distilled water blanks and subsamples read
using 12x75 mm cuvets. Because of the greater sensitivity of the
instrument at Bryte, samples with off-scale readings were diluted
with distilled water to bring them back to a readable range. As
much as possible all samples were read on the same sensitivity scale.

In vivo fluorometry was used after June 30, 1969. Before this time,
growth was measured by the fluorescence of acetone extracts. In-this
method the water sample was filtered through a Whatman GF/C glass
filter, preserved with magnesium carbonate, frozen, and stored in
darkness. The entire filter (with algae) was then ground in a tissue
grinder with 90 percent acetone. The chlorophyll dissolved in the
144
-------
90 percent acetone was measured by fluorometry. Chlorophyll "a"
was distinguished from phaeophytin by a second reading after the
addition of HCL.

Although fluorescence was the principal parameter recorded, on
occasion other data were obtained. Nitrate, pH, absorbency at
410 mu, and volatile solids information was obtained during some
runs.

Results

Growth Limiting Nutrient. The primary objective of one series of
experiments was to demonstrate that removal of nitrate from agri-
cultural waste water would reduce its algal growth potential.
Figure 1 shows the results of 10 percent additions of agricultural
drainage water before and after bacterial denitrification processes.
Algal growth in those cultures containing processed water was
almost identical to Delta water controls. In contrast, the addi-
tion of untreated drainage promoted continuous growth much beyond
that of the other samples. Concentrations of NO^-N in these samples
was 17.9, 0.2, and 0.6 mg/1 for the untreated water and for the two
tested bacterial filters, respectively.

Adding nitrogen back to the water from which it has been removed
will result in a medium with an algal growth potential similar to
the original agricultural waste water. Figure 2 illustrates typical
results of nitrogen re-addition to treated waste water. The addition
of 5 percent bacterial filter water had a slight stimulatory effect
on the algal growth potential of the Delta water. A 5 percent addi-
tion of untreated drainage water resulted in a peak fluorescence
value of approximately 200. Additions of 3 or 6 mg/1 nitrogen
(NaNO-j) to the treated water caused the AGP of these samples to
reach peak values similar to that of the untreated water. Untreated
drainage water had a nitrate concentration of approximately 14 mg/1.

Waters with the chemical composition shown in table 1 gave the algal
bioassay results in figures 3 and 4. The treated and untreated agri-
cultural waste water was added to San Joaquin River (Delta) water at
concentrations of 2, 5, and 10 percent by volume.

In figure 3 the AGP's for effluent from the bacterial filter and the
untreated agricultural drain are compared. The AGP's for the combi-
nations of untreated drain water are all significantly higher than
those with effluent from the filter. Using the data from table 1,
the actual increases of inorganic nitrogen (nitrate, nitrite, and
ammonia) range from 0.3 to 1.6 mg/1 with untreated agricultural
tile drainage water addition and from 0.012 to 0.06 mg/1 increase
with bacterial filter effluent. Apparently the addition of more
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than 0.8 mg/1 NOo-N (5 percent agricultural drainage water) was
enough to cause the maximum increase in growth because the curves
for 5 and 10 percent drain tile water additions are essentially the
same. The stimulation effect produced by the filter effluent would
probably not normally be noted in the Delta water but in this case
the original Delta water nitrogen levels were so low that addition
caused stimulation of growth.

Figure 4 shows a comparison of the bioassays of effluents from the
untreated drainage and from the algal stripping system. The total
inorganic nitrogen concentration in the algal effluent was higher
than in the bacterial filter effluent, 3.73 mgN/1 compared to
0.62 mgN/1 (table 1).

Table 1 - Chemical Data for Firebaugh Samples
September 29, 1969

Chemical
N03-N
N02-N
NH-N
Total Inorganic N
Organic N
P04-P
Untreated
Agricultural
Tile Drainage
Water
(mg/l)
16.3
0.0
0.0
16.3
0.4
0.1
Treated
Agricultural Tile Drainage
Water
Algal Pond
(mg/l)
3.4
0.2
0.13
3.73
1.19
0.1
Bacterial Filter
(mg/l)
0.3
0.2
0.12
0.62
0.48
0.1
The concentration of nitrogen in the algal pond effluent was about
2-3 times as high as would normally be discharged from the treatment
facilities.

In figure 4, each bioassay curve has the total inorganic nitrogen con-
centration present in the sample yielding the curve. Note the diriect
functional relationship between fluorescence peak and nitrogen concen-
tration.

Comparison of Treatment Methods. The organisms in the two treatment
methods use entirely different pathways for removing nitrogen. There-
fore, there was a possibility that the product waters might have
differing effects on AGP even when their nitrogen contents were
similar in concentration. This possibility was enhanced by the algal
separation process which might remove trace metals or other growth
requirements from solution. Although many assays were conducted, it
was often impossible to obtain process effluents with similar nitrogen
150
-------
concentrations. Thus it was difficult to show if either system was
more effective in lowering the algal growth potential of the agri-
cultural waste water based on their nitrogen content alone. Gener-
ally, it can be stated that nitrogen removal lowered the AGP,
regardless of what treatment method was used. Two experiments in
which the effluent nitrogen levels were comparable also indicate
that the two systems were similar in their effect on AGP.

The first experiment was conducted on July 25, 1969, using effluent
from an algal pond and a bacterial filter having total nitrogen con-
centrations of about 1.5 mg/1, but with less than 0.5 mg/1 inorganic
nitrogen. Analysis of variance calculations was performed on
differences between initial and maximum fluorescence readings.
Table 2 shows the 95 percent confidence levels obtained by a multiple
range test. The samples connected by underlines are not different
at the 95 percent confidence level. In all instances both pond and
filter effluents showed significantly lower effect than sump water
addition. The pond and filter effluents were the same at 1 and 10
percent additions, but the algae had a greater nutrient removal
effect at 20 percent addition. Based on nitrogen data both efflu-
ents should have had the same effect at all dilutions.

Table 2 - Comparison of Growth Response in San Joaquin
River Water With Percentage Additions Of
Algal Pond, Bacterial Filter, and Untreated
Tile Drain Water

Untreated Treated
Agricultural Agricultural Tile Drain
Percent Addition Tile Drain Water Water
Algal Pond Bacterial Filter
1%
10%
20%
10.8
37.3
34.9
(Fluorescence ttnlts)
1.2
1.2
0.0
1.2
2.4
14.4
Another experiment conducted on September 25, 1969, again using water
from the algal and bacterial filter systems with less than 0.5 mg/1
inorganic tended to confirm the hypothesis that both methods of treat-
ment affected AGP in a similar manner (table 3). Again the difference
between peak and initial fluorescence of the various percentages of
treated water were lower than noted in comparable percentages of
untreated water. In this study algal, and bacterial effluents were
no different in their effect on algal growth at any dilution at the
95 percent confidence level.
151
-------
Table 3 - Comparisons of Growth Response In
San Joaquin River Water With Percentage
Additions of Algal, Bacterial, and Untreated
Tile Drain Water
September 25, 1969

Untreated Treated
Agricultural Agricultural Tile Drain
Percent Addition Tile Drain Water Water
Algal Pond Bacterial System
1%
10%
20%
4.2
36.2
39.8
(Fluorescence units)
1.3
3.0
1.1
3.0
1.9
1.9
Seasonal Variations in San Joaquin River Water at Antioch., The chlo-
rophyll fluorescence of Antioch water increased from 22.5 fluores-
cence units in mid-June to a peak of 32.5 in late July and gradually
declined to a value of 16.4 by mid-November. Nitrate nitrogen tends
to be lowest in summer and increase in the fall reflecting the
seasonal reductions in algal crop (see table 4).

When Antioch samples are incubated in the laboratory, the chlorophyll
values achieved are similar for all the months tested; see table 4.
Spring and fall samples exhibit growth indicating presence of inor-
ganic nutrients in the Antioch water; summer samples exhibited little
or no growth between initial (field) values and laboratory incubated
values made over a period of 1 week or more. This lack of: additional
yield during summer suggests nutrients were essentially exhausted in
the Delta waters sampled during summer. This finding agrees with
past findings by FWPCA in connection with San Joaquin Master Drain
studies, (Bain, et al., 1968).
152
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Table 4 - Seasonal Chlorophyll and Nitrate Variations
in the San Joaquin River at Antioch Bridge
Chlorophyll Fluorescence
Date
Nov.
Dec.
Jan.
Jan.
Feb.
Mar.
Apr.
June
July
Aug.
Sept
Sept
Oct.
Nov.
Sampled
14,
13,
4,
28,
14,
10,
4,
18,
25,
18,
• 9,
. 29
20,
17,
1968
1968
1969
1969
1969
1969
1969
1969
1969
1969
1969
, 1969
1969
1969
Initial
(field)
0
1
1
1
0
1
3
22
32
27
24
25
21
16
.3
.6
.0
.2
.9
.4
.3
.5
.5
.6
.6
.4
.6
.4
Peak
(AGP)
27.
34.
30.
82.
54.
36.
12.
30.
32.
28.
26.
28.
28.
25.
7
5
8
6
9
2
1
9
5
0
5
3
2
5
NOo-N
(mg/1)
(initial)
..
.43
.61
.74
.95
.53
.22
.18
.04
.05
.08
-- •
.09
.22
a Direct readings at 30X scale. Values before June 1969 were
corrected from extracted samples based on sample splits to
determine conversion factor.
Discussion

Algal growth potential tests in two different laboratories indicate
that nitrate-rich agricultural drainage, when mixed with San Joaquin
River Delta water, stimulates algal growth. Seasonal factors do
not alter this finding although in situ algal crop levels vary
seasonally in the Delta. Control samples from the Delta near Antioch
yielded approximately equal chlorophyll peaks in 14 separate AGP
experiments during a 1-year period.

The waters of the Delta near Antioch vary seasonally in nitrate-
nitrogen concentration. Summer nitrate concentrations of 0,05 mg/1
or less, as nitrogen, produced no significant chlorophyll increases
in AGP tests, suggesting nutrient limitations in these waters.
Additions of nitrate-rich tile drainage increased chlorophyll in
all experiments. Additions of nutrient stripped effluents from
different pilot scale treatment facilities at Firebaugh, California,
produced no additional growth except in cases where nutrient removal
efficiencies were known to be low. Selective removal of nitrate-
nitrogen by anaerobic denitrification or removal of nutrients by
algal cells grown in shallow ponds yielded comparable bioassay
results.
153
-------
The Firebaugh experience suggests that eutrophication due to agri-
cultural waste waters can be controlled by treatment. The experi-
ments do not pretend to forecast receiving water response, but to
promote further evidence concerning the importance of nitrogen
nutrition in controlling western Delta algal populations. The AGP
tests are useful ways to demonstrate tertiary treatment efficiency,
particularly since they measure the effect of treatment on eutroph-
ication symptoms.
154
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Papers Cited

(1) Bain, R. C., 1969. ALGAL GROWTH ASSESSMENTS BY FLUORESCENCE
TECHNIQUES. Proceedings of the Eutrophication-Biostimulation
Workshop, Berkeley, California, June 19-21, 1969.
\
(2) Bain, R. C., et al., 1968. SAN JOAQUIN MASTER DRAIN ON WATER
QUALITY OF THE SAN FRANCISCO BAY AND DELTA, Appendix Part C -
Nutrients and Biological Response. Federal Water Pollution
Control Administration. 116 pp.

(3) JOINT INDUSTRY/GOVERNMENT TASK FORCE ON EUTROPHICATION, 1969,
Provisional Algal Assay Procedure, New York. 62 pp.
155
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HARVESTING OF ALGAE GROWN IN
AGRICULTURAL WASTE WATERS

Bruce A. Butterfield and James R. Jones-*-
Introduction

The U.S. Bureau of Reclamation, the Federal Water Pollution Control
Administration, and the California Department of Water Resources
are currently engaged in a joint study near Firebaugh, California,
to determine the feasibility of removing nutrients from subsurface
agricultural waste water in the San Joaquin Valley. Algae harvesting
is being studied for three reasons. One of the processes being
studied is to grow algae, under controlled conditions, which assimi-
lates the unwanted nutrients into cellular material, and then to
harvest the algae from the suspension. Secondly, removal of
naturally occurring algae will be necessary because disposal into
the San Joaquin Delta-San Francisco Bay System is not desired.
And finally, if anaerobic denitrification columns are used to remove
nitrogen, it will be essential to remove algae before the drain
water enters the unit.

This paper is concerned with the algal removal or separation studies
carried on at the Interagency Agricultural Waste Water Treatment
Center (AWWTC). The studies were divided into two phases. One
phase was concerned with the laboratory evaluation of commercially
available flocculating aids. The other phase; with evaluation of
some commercially available separation devices.

Flocculation-Sedimentation Study

Methods and Materials. In the laboratory evaluation of commercially
available flocculating aids, the source of algae-laden water was the
outside growth units of the AWWTC. The algae were grown in saline
water (total dissolved solids has a yearly range from about 2,000 to
over 8,000 mg/1) with some nutrients added to encourage algal growth.
The predominate algae grown were Scenedesmus quadricauda. Concen-
trations ranged from approximately 150 to 400 mg/1 as volatile solids.
A day's sample was collected in a large container and stored in a dark,
cool place. Subsamples were extracted from it throughout the day.
This was done to eliminate daily variations and to allow comparison
between different flocculants.
Assistant Civil Engineer, California Department of Water Resources;
Civil Engineer, U.S. Bureau of Reclamation, Department of the
Interior, respectively; Fresno, California.
157
-------
In jar tests described below, a total of 56 flocculation aids were
tested alone and in conjunction with these flocculants; aluminum
sulfate, calcium hydroxide and ferric sulfate. The subsamples
with varying flocculation aid concentrations were prepared simul-
taneously and then allowed to settle for 1 hour in a cool, dark
cabinet. The next step was to decant and measure percent light
transmittance of the supernatant. Percent transmittance was scaled
from zero percent (total darkness)' to 100 percent (distilled water)
using a spectrometer at 410 mu. The percent transmittance and
total volatile solids of the uncoagulated sample were also measured.
With these two values, a ratio was developed indicating the amount
of algae removed per sample. The testing of the flocculation aids
was accomplished by optimizing mixing time and rate of mix for the
main flocculants. The criteria were 70 r.p.m. and 3 minutes for
aluminum sulfate and 40 r.p.m. and 8 minutes for calcium hydroxide.
If used alone, they were mixed the same as aluminum sulfate. These
values were obtained using an 800 milliliter sample in a one-liter
beaker mixed by a multimixer with 3-inch by 7/8-inch rectang;ular
paddles.

Discussion

Of the 168 combinations tested, 60 did show some benefit in the
separation process; however, economic evaluation (cost of floccu-
lation aid required) indicated that only the following 24 combi-
nations warrant further investigation:

Flocculation Aid Main Flocculant

1. Dow Chemical Co. PEI 600 aluminum sulfate
2. Dow C-31 none
3. Dow C-31 aluminum sulfate
4. Dow C-32 none
5. Dow C-32 aluminum sulfate
6. Narvan Mines Zeta Floe "0" calcium hydroxide
7. Nalco Nalcolyte 603 aluminum sulfate
8. Nalco Nalcolyte 610 calcium hydroxide
9. Rohm and Haas Primafloc C-3 aluminum sul-fate
10. Rohm and Haas Primafloc C-5 none
11. Rohm and Haas Primafloc C-5 aluminum sulfate
12. Rohm and Haas Primafloc C-7 none
13. Hercules, Inc. Hercofloc 814 aluminum sulfate
14. General Mills, Inc. Genfloc 155 none
15. General Mills, Inc. Genfloc 155 calcium hydroxide
16. General Mills, Inc. Genfloc 156 none
17. General Mills, Inc. Genfloc 156 calcium hydroxide
18. General Mills, Inc. Genfloc 162 none
19. General Mills, Inc. Genfloc 162 calcium hydroxide
158
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Flpcculation Aid

20. American Cyanamid Co. Magnifloc 521-C
21. American Cyanamid Co. Magnifloc 521-C
22. American Cyanamid Co. Magnifloc 820-A
23. American Cyanamid Co. Magnifloc 836-A
24. American Cyanamid Co. Magnifloc 835-A
Main Flocculant

none
aluminum sulfate
calcium hydroxide
calcium hydroxide
calcium hydroxide
The performance of the three main flocculants varies throughout the
year. At certain times, ferric sulfate was tested and found to be
cheaper and perform better than either aluminum sulfate or calcium
hydroxide. At present, they are being monitored on a weekly basis
in order to determine which would be the most economical. Since
iron in the form of ferric chloride (also a flocculant aid) has
been added to the algae growth units as a nutrient, aluminum sulfate
and ferric sulfate have become more effective and calcium hydroxide
less effective.

Carbon has been added to the growth units in the form of carbon di-
oxide and has also affected the efficiency of these three floccu-
lants. Carbon dioxide addition lowers pH, causing ferric and
aluminum compounds to become more effective and calcium hydroxide
less effective. At the AWWTC, a 5.6 pH was found to be optimum,
when ferric and aluminum compounds are used; but this is uneconomical
due to the cost of acid.

Seasonal variations of water quality, temperature, light, etc.,
appear to be influencing factors and must be monitored. A typical
effective series of tests performed in the spring, of aluminum
sulfate, ferric sulfate, and calcium hydroxide is shown on table 1.

Table 1 - Flocculant Effectiveness
(in percent transmittance)
Flocculant
Flocculant Concentration, _mg/l

Ferric Sulfate
Aluminum Sulfate
Calcium Hydroxide
0
63
63
67
3
88
64
66
5
94
65
66
10
94
66
67
20
95
74
70
40

94
93
80

95
The percent transmittance of the original sample was 6 percent and
the volatile solids were about 500 mg/1. The zero concentration
shows the effect of ferric chloride addition to the growth pond;
however, no carbon dioxide was being added then.
159
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Pilot Harvesting Studies

The second phase of separation studies involved the evaluation of
pilot-scale separation devices. The units included flocculation
and settling units, centrifuges, a microscreen, a vacuum filter, a
rapid sand filter, and sand drying beds. It was planned that these
units would give an indication as to how traditional separation
equipment would work on algae-laden water at the AWWTC.

The algal concentration of growth pond effluent varies from 150 mg/1
to 400 mg/1 (0.015 to 0.04 percent by weight). Algae separation is
divided into three stages: concentrating, dewatering and drying.
Concentrating increases the algae solids to l-to-4 percent.
Dewatering increases the solids to 8-to-16 percent. Drying processes
bring the solids to 85-to-92 percent. Destruction of the algae cell
and denaturing of the protein occurs when drying exceeds approxi-
mately 92 percent.

Flocculation and Sedimentation. Algae at Firebaugh can be concen-
trated to about 1 or 2 percent by weight through flocculation and
sedimentation. Settling as a procedure for harvesting of algae is
hindered by the small size of Scenedesmus quadricauda (10-40 micron)
and its specific gravity (approximately 1.006). Auto-flocculation,
the tendency for algae to clump together and settle, occurred
naturally under certain conditions in the rapid growth pond.

A complete self-contained water treatment plant was used for concen-
tration studies. Installed in the settling chamber was a modular
unit of 1-1/2-inch-diameter settling tubes at a five degree incli-
nation to the horizontal. The tubes were installed to reduce the
settling distance of the algae. When the tubes were drained or
backwashed, the algae sludge flowed down and out of. the inclined
tubes.

In general, when transmittance of the settling tank effluent fell
below 90 percent transmittance the unit was backwashed. The amount
of water needed to backwash the tubes was 5-10 percent of the product
water and contained less than 1 percent algae by weight. Aluminum
sulfate was used as a flocculation aid in the unit. With an influent
pH above 9.0 and detention time of 2 hours, 300 to 400 p.p.m. of
aluminum sulfate were needed to remove the suspended algae during
the fall.

Upflow Clarification. One of the concentration devices tested at
the AWWTC was an upflow clarifier. As algae-laden water flows upward,
the cross-sectional area increases and the velocity decreases causing
a settling to take place. At this point, a blanket of floe developed
causing a filtering effect. The sludge or concentrate was drawn off
at this point and clarified liquid was passed off at an upper level.
160
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The operation involved pH adjustment (to approximately 10.8) of the
influent with sodium hydroxide to flocculate the suspended solids.
At times the blanket appeared to plug the unit and stop all flow.
This was followed by a breakup of the blanket and short-circuiting.
The operation removed 90 to 95 percent of the suspended solids in
the 2 to 4 percent solids concentration range.

Centrifugation. Investigations were made into the application of a
solid bowl continuous horizontal centrifuge and a yeast-type nozzle
centrifuge. A self-cleaning centrifuge, similar to the yeast sepa-
rator but with added features, will be tested.

The centrifuges were tested both as algae concentrators and dewaterers.
The dewatering study used algae water concentrated in a sedimentation
unit using aluminum sulfate. A progressing cavity pump or a gravity
feed system was used in all cases to provide a steady, nonpulsing
flow.

The solid bowl centrifuge tested was a 6-inch pilot unit. Variables
included flow rate centrifugal force, and depth of liquid in the
bowl. The bowl depth controlled the sludge consistency from high
flow and wet cake (higher efficiency of algae removal) to low flow
and dryer cake (lower efficiency). In general, algae concentrations
of 3 to 22 percent by weight were achieved, but the efficiency was
usually less than 10 percent. An efficiency of 28 percent was
achieved, but with high flow and wet cake. Whether used for concen-
trating or dewatering, the efficiencies were comparable, but due to
the large volume that will need concentrating, it would not be economi-
cal to use a solid bowl centrifuge except for dewatering. The solid
bowl centrifuge was found to be relatively maintenance-free.

The yeast-type nozzle centrifuge is designed for solid/liquid and
solid/liquid/liquid separation with continuous feed and removal.
Centrifugal force is constant and the solids discharge is controlled
by varying the number and size of nozzles. Maximum flow rate was
1-1/2 g.p.m. With flow rate below 1/2-gallon per minute, no removal
was achieved due to lack of cake buildup in the bowl. As a primary
concentrator this unit obtained removals greater than 80 percent,
but would soon plug with algae and suspended clay material. As a
dewaterer, it would plug sooner with the heavier algal loading.

Screening. A vacuum filter and microscreen are being evaluated.
The vacuum filter has not been tested sufficiently to make any conclu-
sions. In conjunction with this unit, a leaf kit filter was supplied
to help in evaluating the effectiveness of different filter material.
A close-weave monofilament nylon material (120 by 240 threads to the
inch) showed promise in separation and was relatively easy to clean
which is an important factor in economics. Several synthetic felts
gave acceptable results.
161
-------
An automatic, rotating, drum-type, straining system was tested for
separation of algae. The unit consisted of a self-contained 4-foot-
diameter by 1-foot-wide rotating drum. Screens of 25 micron and
35 micron were supplied with the unit. Algal-laden water entered
the interior of the partially submerged drum and was strained as
the water flowed outward through >the revolving screen. The algae
was caught on the screen and washed off by a row of water jets
located above and outside the drum. It became apparent that the
25 micron screen allowed the smaller algal cells to pass. With the
25 micron screens, the unit removed up to 8 percent of the algae
in a slurry flow of approximately 1 percent of the total influent.

Rapid Sand Filtration. A cross-flow sand filter was evaluated as
a primary algal concentrator. This filter consisted of two sand
beds 3/8 inch thick, 5 inches wide, and 5 feet high. The sand was
contained between two pieces of fine-weave nylon monofilament cloth,
which was supported by 3/8 inch wide plastic spacer strips. The
raw water was pumped up between front and back plastic covers in
the space formed by the plastic spacer strips. It then passed
through the sand bed from both sides toward the center open space
provided by more 3/8-inch spacer strips. The product filled a
column above the filter and overflowed at the top. The water in
the column was used to backflush the filter when the pressure
difference through the sand bed reached a predetermined level. It
became apparent that the sand bed was becoming plugged with algae
as the time between backwashes became shorter. The algae removal
was over 90 percent (without chemical addition) and the solids
content of the sludge, or backwash, was as high as 10 percent.

Future Work

The objective during the next year will be to monitor seasonal vari-
ations that affect the harvesting of algae and to refine operational
procedures. Seasonal monitoring for chemical requirements will be
maintained. Additional seasonal monitoring of the physical charac-
teristics of algae will be maintained to extend the evaluation of
hardware in the dewatering and drying processes. The evaluation of
the microscreen and vacuum filter will be continued to test various
filter materials. A self-cleaning basket centrifuge will also be
evaluated. Future separation work will include flotation studies.

Conclusions

Through laboratory and field testing, it is obvious that effective
concentration can be accomplished using the flocculation-sedimentation
process to remove 90-95 percent of the suspended solids from algae-
laden agricultural waste water. It appears that dewatering and
162
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drying can be accomplished but the efficiencies of the units tested
at AWWTC were low. The need to recirculate the water would increase
the overall cost; however, it is believed better results will be
achieved in larger capacity units.
163
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COMBINED NUTRIENT REMOVAL AND
TRANSPORT SYSTEM FOR TILE DRAINAGE
FROM THE SAN JOAQUIN VALLEY

Joel C. Goldman, James F. Arthur,
William J. Oswald, and Louis A. Beck1
Introduction
Current plans call for treatment of agricultural waste water for
nutrient (nitrogen) removal from the proposed San Luis and Master
Drains prior to discharge into the Bay-Delta Area. Of the several
treatment processes currently being investigated, the algae
stripping process was estimated to have required between 6,000 and
12,000 acres of land to accomplish this task. The original proposal
for utilizing the algae process considered only the use of a sepa-
rate treatment facility to be located adjacent to the Drain some-
where along its length. Because every body of water is a potential
algal growth system, this proposal will demonstrate that there are
several alternatives to the original plan, which will greatly reduce
the total cost of treatment and perhaps improve the overall effi-
ciency of nutrient removal.

General Aspects of Proposal

Objective. It is the objective of this report to present alternate
solutions for the treatment of drainage water through the use of
In-Line Treatment. This treatment will utilize components of the
Drain, which were originally designed solely for the transport and
storage of drainage water. Specifically, it will be demonstrated
that with certain modifications, the Drain, itself, can be used as
a partial treatment unit with nutrient removals of up to 40 to 50
percent, and that with similar modifications, the Drain up to
Kesterson, together with the proposed Kesterson storage reservoir,
can accomplish up to 100 percent nutrient removal.

Basic Assumptions. The Drain, as planned, will promote a degree
of algal growth regardless of design and use which will result in
1 Assistant Civil Engineer, California Department of Water Resources,
Fresno, California; Research Aquatic Biologist, Federal Water
Pollution Control Administration, Fresno, California; Professor of
Sanitary Engineering and Public Health, University of California,
Berkeley, California; and Senior Sanitary Engineer, California
Department of Water Resources, Fresno, California, respectively.
165
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incorporation of soluble nutrients into cells and the resultant
reduction of soluble nutrients, which will necessitate some form
of algae separation before terminal discharge into the Bay-Delta
waters.

The San Luis Drain, as it is now proposed, has a surface area of
approximately 770 acres and with the expected flow will have a
mean detention time of 6.3 days. Based on these considerations, it
is highly likely that the Drain will support an undetermined but
possibly significant algal growth at the point of discharge into
the Delta, depending on time of year. This growth will occur natu-
rally due to the high level of nutrients that are present in the
drainage waters, together with the prevailing environmental condi-
tions (sunlight and temperature) that are present in the San Joaquin
Valley from early spring through late fall. Growth may take one or
both of two forms; sessile algae growing on the canal walls in the
photic zone, or suspended algae growing in the photic zone but
uniformly distributed in the cross-section'of the flow.

Unless specifically removed, it is likely that suspended algae will
pass unaltered through any subsequent process, while sessile algae
will break off the walls in clumps, which will then clog any filtra-
tion process.

Since algal growth in the Drain will be unavoidable, maximization of
this growth, followed by complete separation of the algal biomass,
will result in the following benefits:

a. Land requirements for the treatment facility will be
reduced in proportion to the degree of induced algal growth in the
Drain. Thus, the principal cost for treatment will be reduced.

b. The Drain will be put to a dual use—concurrent transport
and treatment of drainage water.

c. The velocity of the Drain is great enough to provide a degree
of turbulence, which will meet part or all of the mixing requirements
necessary to promote the optimum algal growth desired; power require-
ments for this growth will be reduced, thus reflecting still another
cost reduction.

Kesterson Reservoir, as originally envisioned, was to act as a
storage reservoir to hold the first 2 years of drainage flows from
the San Luis Drain (from December 1969 to December 1971), while
the northernmost portion of the Drain from Kesterson to Antioch was
being constructed. With an estimated annual inflow to the San Luis
Drain during these years of approximately 2,500 acre-feet, the
166
-------
reservoir will store 5,000 acre-feet of water. Based upon a proposed
3-foot depth, the reservoir will initially encompass a land area of
about 1,700 acres. Eventually the land area of the reservoir would
be built up to about 3,000 acres to serve a variety of uses.

At the time the northern section of the Drain is completed and
Kesterson Reservoir is emptied of the 2 years' storage, it is possi-
ble that a substantial growth of algae will have formed in the
reservoir which will further increase the amount of algae to be found
in the Drain. It is not unrealistic to foresee an algal concentration
of up to approximately 100 mg/1 or more in the Drain at Antioch during
the period the reservoir is being emptied. Based upon light consid-
erations only, the depth of the Drain at Antioch will limit the
maximum concentration of algae that can be supported there to
100 mg/1 (see calculations in Appendix).

Current Status of Treatment Processes. Research has been underway
at Firebaugh for over 2 years to determine the feasibility of removing
nitrogen from agricultural drainage water by either algae stripping,
anaerobic denitrification in either deep ponds or filters, or a
combination of both.

The anaerobic filters have demonstrated a high efficiency during
most of the year but appear to be sensitive to temperatures below
12°c. and experience problems of clogging after prolonged operation.

The algae stripping process during the course of the 2 years of re-
search has shown a steady improvement in efficiency, due in part to
algal adaptation, but also due to increased knowledge of the proper-
ties of the process by those conducting the studies. It has also
been shown that over 95 percent of the algal cells can be separated
from the liquid effluent through coagulation with small quantities
of lime or alum, followed by sedimentation.

Thus, both processes appear to be technically feasible, and one can
envision the types of systems in which they would be used. For
example, several candidate systems are shown in figures 1-A, 1-B,
and 1-C. A combined process (figure 1-C) in which algae are grown
and removed prior to column denitrification would give the greatest
factor of safety at approximately the same cost as either of the
two separate processes (figures 1-A and 1-B).

Effect of In-Line Treatment on Overall Cost of Different Proposed
Treatment Processes. Algae Stripping Process--An acceleration of
the treatment process through the provision of a high initial bio-
mass (the algae grown in the Drain) with a reduction in the soluble
nutrient level will decrease costs by:
167
-------
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168
-------
a. Reducing the land requirements for a treatment plant.

b. Reducing the construction costs of the plant.

c. Reducing power and maintenance costs for a treatment plant.

Anaerobic Denitrification Filters—As noted previously, it will be
difficult, if not impossible, to eliminate endemic algal growth from
the Drain under existing nutrient and light conditions. Any nitrogen
incorporated into algal cells in transit will be unavailable for
treatment by denitrification, if the cells pass through the filter.
This nitrogen will then be discharged to the Delta and eventually
could be regenerated as soluble nitrogen. If the cells remain in
the filter, then a further problem of filter clogging will arise.
Research currently in progress at Firebaugh to determine what effect
algal-laden water will have on the filters indicates that it adversely
affects filter performance by increasing the concentration of soluble
nitrogen in the filter effluent.

Thus, if algal growth in the Drain could be optimized and the result-
ing algae separated prior to filter treatment, the unit cost of
treatment (which includes separation) could be reduced in the
following ways:

a. The total area requirements for terminal treatment will be
reduced approximately in proportion to the reduction in soluble
nutrients (principally nitrate-nitrogen). The land area required
for separation facilities will be small compared to the reduction
in land area required for the filters.

b. Filter construction costs will similarly be reduced.

c. Methanol costs will be reduced in proportion to the amount
of nitrate-nitrogen removed by In-Line Treatment.

d. Power and maintenance costs will similarly be reduced.

Suggested Modifications to Improve In-Line Treatment

As previously stated, the Drain without modification has the poten-
tial for reducing nitrogen levels by a significant amount. Similarly,
Kesterson Reservoir outflow will increase the algae concentration
in the Drain by as much as 100 mg/1. Therefore, any modification to
the Drain which enhances this efficiency will have significant
economic value, when compared to the original estimate for treating
Drain water solely in a terminal plant. A number of different
alternatives to the original algae stripping proposal thus becomes
apparent. These are as follows:
169
-------
Enhance Algal Growth in the Drain by Seeding and Nutrient Addition
(If Required). It will be necessary to seed the Drain at Kettleman
City with approximately 50 mg/1 of algae in order to produce
100 mg/1 of algae at Antioch (see Appendix). Work at the Firebaugh
Treatment Center has indicated that the Alamitos Sump water is
deficient in carbon, phosphorus and iron; three nutrients required
to support an algal growth capable of high nitrogen uptake. In
order to promote algal growth at Firebaugh, it has been necessary
to add small quantities of these three ingredients to the sump water.
If a similar nutrient limitation is present in the combined drainage
waters feeding the San Luis Drain, then nutrient addition would be
required along with the initial seeding. However, it should be
pointed out that the Alamitos Sump water is fed by an isolated tile
drainage system. The fact that the San Luis Drain will be fed by
numerous drainage systems in the San Joaquin Valley greatly reduces
the prospect that the composite drainage water will be lacking in
either iron or phosphorus. Carbon is available to the algae only
in the form of carbon dioxide or its derivative, the bicarbonate ion
Work at Firebaugh has indicated that there appears to be a seasonal
change in the CC>2 requirements necessary for high nitrogen conver-
sion into algal cellular material. Thus, it is possible that supple-
mentary C02 will not be required or may be required only during a
portion of the year and during several hours of the day.

Seeding of the Drain could be accomplished by maintaining a growth
pond at Kettleman City which would feed into the Drain. It is
estimated that a 1,000-acre pond will be necessary to produce the
required 50 mg/1 initially in the Drain.

Thus, it would be possible to reduce soluble nitrate-nitrogen levels
at Antioch by up to 40 percent by using the Drain as it is presently
designed with seeding and nutrient additions (if required). Land
requirements and construction costs for a treatment plant would be
similarly reduced by 40 percent.

Keep the Drain Essentially as Proposed bjit Include Kesterson
Reservoir as a Permanent Part of the Flow-Through System. If
Kesterson Reservoir were a permanent part of the Drain System with
a detention time of 10 days at peak flow (at a 3-foot depth), then
it would be possible to produce 100 mg/1 of algae in the reservoir
effluent, thus eliminating the need for initial seeding. Nutrient
addition may be required in accordance with the previous discussion.
As in the first proposal soluble nitrate-nitrogen levels at Antioch
would be reduced 40 to 50 percent with a corresponding savings in
the cost of treatment.
170
-------
Modify and Use All or Part of the Drain for Partial Treatment.
Assuming nutrients are not limiting, the growth of algae is primarily
dependent on the quantity of available light energy. In an outdoor
system, sunlight is the sole source of this energy. Thus, the
quantity of energy available for the photosynthetic process is
directly proportional to the amount of surface area exposed to
sunlight.

With regard to using the Drain as an algal growth system, any method
that will increase the effective surface area of the Drain will
increase the photosynthetic efficiency and improve the treatment
process.

Several obvious ways to increase this effective surface area
include:

Increase the Surface Area of the Drain—Ideally, in order to accel-
erate the growth of algae in the Drain, itself, the entire Drain
should be constructed so as to optimize surface area and minimize
depth. In order for the Drain to act as a sole treatment unit, its
surface area would have to be increased sevenfold over the' current
design. Since no recommendations have been made concerning choice
of nutrient removal process at this time, and because the Drain up
to Dos Palos has already been designed, there does not appear to be
any justification for further consideration of widening the Drain.

Hydraulically Modify the Drain to Create Turbulence--A direct rela-
tionship exists between the degree of turbulence and effective surface
area. By utilizing the flow of the Drain for mixing and hydraulically
modifying the Drain to create turbulence, the overall photosynthetic
efficiency of In-Line treatment can be greatly improved.

Modifications to be considered are:

a. Baffles along the bottom and/or sides to create turbulence
(at the projected velocities).

b. Drop structures strategically along the length of the Drain
(at the projected velocities).

c. Aeration with air (or CC>2 enriched air) to create turbulence;
aeration could be effected as in an aeration tank of an activated
sludge plant. Aeration units could similarly be located strategically
along the length of the Drain.

d. Pumps at intervals along the Drain to promote turbulence.
171
-------
However, without further investigation, it is difficult, if not impos-
sible, to quantitatively predict what degree of turbulence is required
to produce a desired algal concentration.

Kesterson Reservoir as a Combined Storage Reservoir-Treatment Plant.
Essentially, a major portion of the San Luis drainage flow and the
bulk of the nitrogen load will enter the Drain before Kesterson
Reservoir. Since the land for Kesterson Reservoir (on the order of
3,000 to 6,000 acres) has already been selected as a large part of
the overall drainage system, the concept of converting Kesterson
Reservoir into a combined storage reservoir and treatment plant appears
to be most promising.

By converting the reservoir into an algal growth system with operating
depths varying from 1 foot to 3 feet, the system has the capability for
over 90 percent treatment and still has the flexibility for acting as
an emergency storage reservoir.

Studies at Firebaugh, thus far, indicate that some degree of mixing
is required in algal systems for optimum growth and nutrient removal.
Research to date indicates several hours of mixing per day appears
adequate although research involving shorter mixing periods, which
also appears favorable, is continuing in this area; but, regardless
of the degree of mixing, it will be a consideration in determining
operational costs for a treatment plant.

From the start of this project, mixing was recognized as a major
operational factor in the algae stripping process and, as a result,
several proposals have been brought forth as how to best accomplish
this objective. It has been suggested that pumps might be centralized
in turret fashion to serve several series of ponds to minimize opera-
tional costs or that pumps could be installed in a racetrack-type
pond, such as at Firebaugh. Any treatment plant utilizing these
types of mixing systems will require substantial amounts of power
which will directly affect the total processing costs.

The system proposed for combining the reservoir for storage and
treatment would minimize the power required for mixing by either a
complete gravity or combined initial pumping-gravity flow system.
The land of Kesterson Reservoir embodies a natural slope to the north.
Thus, a minimum amount of cut and fill would be required to produce
a slope of the required degree. Excavated earth could then be effi-
ciently used for side slopes. If necessary, low cost pumping could
be used initially to produce the necessary velocities in the treatment
process.

A design of such a treatment facility, which lends itself very effect-
ively to the dual use proposed, entails a series of equally spaced
172
-------
channels running longitudinally along the length of the reservoir.
Figure 2 is a sketch of such a proposed plant. The channels would
follow the natural slope and the flow through each channel could
be regulated by individual head gates. Similarly, these gates
could isolate each channel for treatment flexibility and/or
maintenance.

Any desired detention time could be maintained by recirculating a
portion of the effluent. This design will have the following
inherent advantages over a terminal treatment plant as originally
envisioned:

a. Greatly reduces construction costs due to the simplicity
of design.

b. Provides a great degree of flexibility of operation--can
adjust to seasonal variations in flows.

c. Minimizes power requirements by using gravity for a part of
the required mixing.

d. Prevents biomass buildup by eliminating stagnant areas that
are often present in ponds of the Firebaugh design.

e. Allows for cyclic removal, if required.

f. Treatment can still be carried on while the system is being
used as a reservoir.

g. When the Master Drain is put into operation, the reservoir
can be expanded to meet future treatment requirements (see sketch).

The first stage of Kesterson Reservoir has already been designed and
encompasses a series of 12 ponds, each 3 to 4 feet deep. The total
land area involved is in the order of 1,300 acres. There still
remains 3,000 to 4,000 acres of land which can be utilized for the
combined algal growth system and storage reservoir. Figure 3 is a
location map of the proposed Kesterson Reservoir and shows the por-
tion already designed, together with the land area available for
future reservoir use. Figure 4 is a site plan of the system, showing
how an algal system, as envisioned in figure 2, could be incorporated
into the land area reserved for the remainder of the reservoir.

If the size of the reservoir were 4,000 acres, together with the
1,300 acres for the first stage reservoir, then up to 90 percent of
the influent nitrogen from the San Luis Drain waters could be incor-
porated into algal cell material (see Appendix for calculations).
Perhaps the most significant aspect of using Kesterson Reservoir as
173
-------
FIGURE 2
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FUTURE EXPANSION
LOW HEAD PUMPING
IF REQUIP.ED-
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KESTERSON
RESERVO I R
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FLOW DIAGRAM
PROPOSED COMBINED RESERVOIR AND ALGAL
STRIPPING PROCESS
NO SCALE
TYPICAL CROSS SECTION
NO SCALE
*
1
N
174
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FIGURE 3
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STATE OF CAt-IFORKIA

THE RESOURCES AGENCY

DEPARTMENT OF WATER RESOURCES

SAN JOAOUIN DISTRICT
LOCATION MAP
KESTERSON RESERVOIR
SAN LUIS DRAIN
175
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176
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a treatment unit is that it has the potential for future conversion
into a stripping plant, if it were necessary to delay installing any
treatment process until some time after construction of the entire
Drain, including the reservoir. No additional land would be required
for such a process, resulting in a very significant savings in cost.

Similarly, the system may be expanded conveniently as the flow in
the Drain increases. Thus, it would be possible to build the treat-
ment plant in stages concurrent with those to increase the storage
capacity of the reservoir.

Combine the Algae Stripping Process and the Anaerobic Filters in
Series. Inasmuch as the studies at Firebaugh indicate that both the
anaerobic filters and the algae, stripping process are technically
feasible, the concept of combining the two systems in a series-type
operation (see figure 1-C) merits intensive investigation. Kesterson
Reservoir, as outlined in the previous section, could serve as the
site for the algae stripping process, followed by algal separation
facilities, and then followed by the anaerobic filters for final
treatment. A significant aspect of this design is that it inher-
ently emodies a substantial factor of safety and insures a polished
drainage water virtually free of nitrogen and other nutrients even
under extreme circumstances.

If a dependable market can be found for the harvested algae., it is
reasonable to assume that a substantial fraction of the cost of the
entire treatment facility can be defrayed. The whole system could
be easily expanded to meet future needs.

Table 1 gives a gross estimate of both land and cost saving;s that
could be achieved by In-Line Treatment. As can be seen from this
table, a savings of approximately $11 to $12 million is possible
when in-line treatment is used for 90 to 100 percent nitrogen
removal as compared to terminal treatment facility as originally
envisioned.

Summary

Work at Firebaugh has demonstrated that it is possible to remove
nitrogen from drainage water by either algae stripping or anaerobic
denitrification.

It has been suggested in this proposal that serious consideration
be given to In-Line Treatment as both an economical and practical
method for nutrient removal.

Because Kesterson Reservoir is an integral part of the proposed
drainage system and contains the required area needed for treatment
by algae stripping, it seems logical to use it as a dual-purpose
treatment and storage reservoir.
178
-------
Kesterson Reservoir, if modified as suggested, has the potential
to provide nitrogen removals in excess of 90 percent.

The Drain, itself, has the capability for partial treatment. Al-
though it may be impractical to physically modify the dimensions
of the Drain for enhancing algal growth, it is possible to use the
Drain for this purpose by creating turbulence, adding nutrients,
and by seeding.

Work at Firebaugh has demonstrated that it is technically feasible
to remove nitrogen by growing and harvesting algae. However, at
this time, there are many unanswered questions about the process.
Some of the more important problems to be solved include:

a. What are the optimum nutrient conditions required for
maximizing nitrogen removal?

b. What is the optimum detention time?

c. What is the maximum depth under which the process will
work? For design purposes in this report, a depth of 1 foot has
been used, This depth has been found to be adequate for maximum
nitrogen removal at Firebaugh. However, there are some indications
that greater depths will be as efficient. If this holds true, then
this proposal for In-Line Treatment will be conservative in its
estimates of land required.

d. What degree and duration of mixing is required?

The combining of the algae stripping process with the anaerobic
filters in a series operation at Kesterson Reservoir would insure
an efficient system under the most extreme circumstances and would
provide the maximum operational flexibility.

It appears from this brief preliminary analysis of the situation that
the use of In-Line Treatment can reduce treatment costs considerably.

Recommendations

Based on the analysis contained herein, it is strongly recommended that
a more comprehensive analysis of the use of In-Line Treatment be made
in the near future. This analysis should include actual design of an
In-Line Treatment unit with estimates of construction costs of In-Line
Treatment, estimated operational costs, and, inasmuch as algal treat-
ment is dependent on defraying the overall cost through economic
recovery of the value of algae, further detailed investigation for
finding an economic market for the algae byproduct.
179
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APPENDIX
A. Detention Time in San Luis Drain
Characteristics of Drain
Length
Segment (miles)
Kettleman City 12
to Highway 198
Highway 198 15
to Jameson Ave.
Jameson Avenue 7
to Lassen Ave.
Lassen Avenue 17
to Tranquillity
Tranquillity 62**
to Kesterson
Russell to 10
Ness Avenue
Kesterson to 75
Antioeh
Plow Bottom
Capacity Width Depth
(cfs) (ft) (ft)
100 6.0 5-5

150 7.0 6.4

200 7.0 7.3

300 8.0 8.0

300 8.0 5.8

450 10 9.7

Cross*
Sectional Volume1
Area
(ft2) ft3xlO
78.4 4.97

106.1 8.42'

131.2 4.87

160.0 14.4

160.0 43.9

96.9 5.06

237*** 93.2

Deten-
tion
Time
( days )
0.577

0.650

0.281

0.556

1.695

0.195

2.410

TOTAL DETENTION TIME = 6.364

* All side slopes 1.5:1
** Russell to Ness Avenue is included in the Tranquillity to Kesterson segment,
*** Not available if treatment is carried out at Kesterson.
B. Maximum Algal Growth Possible in Drain Under Natural Conditions

The San Luis Drain has a surface area of 770 acres and a mean deten-
tion time of 6.3 days. If 1 mg/1 of algae were initially presented
in the Drain, and assuming an average of four cell doublings during
transit to the Delta, then 16 mg/1 of algae would be present at
discharge. However, consideration must be made of the fact that if
even 2 mg/1 of algae were present initially and the same number of
doublings occurred, then the Drain would contain 32 mg/1 of algae.
One more doubling would bring the level of algae to 64 mg/1.
180
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Therefore, it is almost impossible to predict the amount of algae
which the Drain will contain both initially and at discharge into
the Delta. It should be recognized, however, that the Drain does
have the potential for supporting a relatively high concentration
of algae and that consideration of this fact should enter the
design of any nutrient removal process.

C. Amount of Nitrogen Removed From Drainage Water By Naturally
Occurring Algae

Assumptions

a. Algae concentration at discharge = 16 to 65 mg/1. (Estimate)

b. Nitrogen content of algal cells = 8-10 percent (use 8 percent)

c. Total nitrogen concentration in drainage water = 20-25 mg/1
(use 25 mg/1).

d. Therefore,

amount of nitrogen removed from drainage water and converted
into algal cell material is:

16 mg/1 x 0.08 = 1.28 mg/1 (minimum estimate)

64 mg/1 x 0.08 = 5.12 mg/1 (maximum estimate)

or approximately:

JL-28 x 10° = 5 percent (minimum estimate)

5.12 x 100 _ on „ , . ,
c - 20 percent (maximum estimate)

of the incoming nitrogen will be removed.

D. Amount of Algae Theoretically Possible in Outflow From Kesterson
Reservoir

Assumptions

a. Maximum flow in San Luis Drain = 290 MGD

b. Surface area of Kesterson Reservoir = 3,000 acres

c. Depth of reservoir = 3 feet (normal operating depth).
181
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Detention Time = 3,000 x 43.560 x 3 x 7.48 = 10 Days
290 x 10&
Assume that in April and September conditions are critical

Average solar energy during these months = 8 x 10° K
cal/acre/day.

Total energy/reservoir/day = 3,000 x 8 x 106 =
24 x 109 K cal.

Assume that photosynthetic efficiency in converting solar energy
to algal biomass = 3 percent

Algae contain 6 K cal/gram (average value)

Therefore, amount of algae produced per day in pond equals

24 x 109 x 3 x 10-2 = ?
Average algal concentration in outflow from Kesterson
Reservoir =

_ 12 x 1010 ms £•. 100 n
290 x 106 x 3.79

Based upon calculations in part F of the Appendix, the Drain at
Antioch has the capability for supporting approximately 100 mg/1 of
algae based upon light limitations only. Therefore, it is possible
that 100 mg/1 of algae leaving Kesterson Reservoir will still be
present at Antioch, the point of discharge to the Delta.

E. Nitrogen Conversion To Algal Cells in Kesterson Reservoir When
Used as a Treatment Unit

a. Nitrogen removal in First-Stage Storage Reservoir

Area = 1,300 acres
Depth = 3 feet
Flow Rate = 290 MGD

Detention Time = 1.300 x 43.560 x 3 x 7.48 _ 4>3 d
290 x 106

Same assumptions for solar energy conversion into algal bio-
mass as in Part D.
182
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Therefore, amount of algae produced per day in pond equals:

(1.3 x 103) (8 x 106) (3 x 10"2) = 5.2 x 107 grams
6

Average algal concentration in outflow from First-Stage
Reservoir equals

5.2 x 1010 mg = 47 mg/1
290 x 10° x 3.79

b. Nitrogen Conversion to Algal Cells in Combined Treatment Plant-
Storage Reservoir

Area = 4,000 acres
Depth = 1 foot
Flow Rate = 290 MGD

Detention Time = 4,000 x 43,560 x 1 x 7.48 _ ^5 D g
290 x 106

Total energy/reservoir/day = 4,000 x 8 x 106 = 32 x 109 K Cal

Assume that photosynthetic efficiency in converting solar
energy to algal biomass = 5 percent (5 percent could be obtained
due to excellent hydraulic design of reservoir and greater depth).

Amount of algae produced per day in pond equals

32 x 109 x 5 x 10"2 = 26.7 x 107 grams
6
Average algal concentration in outflow from Treatment Plant =

26.7 x 1010 mg = 243 mg/1
290 x 106 x 3.79

Total algae produced in Kesterson Reservoir = 243 + 47 =
290 mg/1

Assume: Nitrogen content of algal cells = 8 percent.

Influent nitrogen content = 25 mg/1.

Thus,

Total Nitrogen in Algal Cells = 290 x .08 10Q =
25
93 percent
183
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F. Algal Growth Required For 90 Percent Nitrogen Removal

Algal cell material has an energy content of 6 K cal/gram or
6 x 454 = 2,724 K cal/lb. (dry weight) See attached Character-
istics of the San Luis Drain (page 180).

Sunlight Energy Input:

To compute solar energy flux (S) input to surface of Drain
(Assume critical conditions in April and September); there-
fore,

Daily Energy Input (S) = 2 x 102 cal/cm2/day

and, energy to 1 acre = 2 x 102 x 4,025 x 107 x 10"3
K cal/cal = 8 x 106 K cal/acre/day

Necessary Energy Output - Entire Drain

450 sec. ft. = 290 million gallons per day

Nitrogen content of drainage water = 25 mg/liter (maximum)

Assume 90 percent removal; therefore, there will be 22.5 mg/
liter in algal cells.

Algal biomass to be produced at 50 percent protein =
50/6.25 = 8 percent N, therefore, biomass to be produced
= 22.5/.08 = 280 mg/liter.

Therefore, final algal concentration should be 280 mg/liter,
and the corresponding required biomass production per day is
280 x 8.34 x 290 = 675,000 Ibs. per day.

G. What Can Be Done To Grow Algae in The Drain

In order to use the Drain most strategically as a growth unit, it
will be necessary to seed the Drain with a concentration of algae
sufficient to give complete light absorption initially and to permit
as many doublings as possible to occur during transit. With good
mixing, doubling will start at once and may continue up to a concen-
tration permitting 1/3 d light transmission.

In this case the Drain would be initially seeded with a concentration
proportional to the mean depth at Kettleman which is 3.77 ft.
184
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d = 3.77 x 30.48 = 115 cm
Using the Beer-Lambert equation for concentration as a function of
depth, the concentration of algae at Kettleman should be:

c -
C - 115 x 15 x 10-3 - 52
and at the end of the 6.3-day transit the concentration would be

d = 6.15 x 30.48 = 188 cm (Depth at Antioch)

Cc = 188 x 1.5 x 10-3 x 3 = 100 mg/liter
Antioch concentration will be light limited at 100 mg/liter and
to attain any further increment shallow ponding would be required.

The increment of 48 mg/liter between Kettleman and Antioch would
constitute fixation of 48 x 290 x 8.34 x 2,724 =

310 x 10 K cal of solar energy in the form of algae or

310 x 106 = 40.4 x 104 K cal/acre/day
7.67 x 102

The mean conversion efficiency would be

40.4 x 104
8 x 106
x 100 = 5.06 percent. 5.06 percent conversion
efficiency is higher than the anticipated efficiency of 3.5 per-
cent in the originally planned 5,800 acres of 12-inch-deep ponds.
However, a 5.06 percent conversion efficiency may be possible
because of the greater depth and light absorption and the excel-
lent mixing provided in the Drain if it has a velocity of 2 feet
per second. The 767-acre Drain, itself, thus would be equivalent
to roughly 1,000 acres of regular growth ponds at Antioch.

H. How Could the Drain Be Best Used to Accomplish the Above?

The strategy would be as follows:

Grow algae at Kettleman City and seed the Drain with about
52 mg per liter dry weight basis.

Required acreage at Kettleman City about 1,000
Acreage equivalent of Drain 1,QQQ
Total land in seeding and conveyance 2,000
Balance of land required at north end
5,800 - 2,000 = 3,800 acres
185
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As one may see, a substantial savings in total land as well as a
savings in expensive "north end" land could result from this scheme.

Inasmuch as land in the vicinity of Kesterson is probably much less
expensive than land in the vicinity of Antioch, and because there is
to be a pond there anyway, it might be worthwhile to consider opera-
ting a major growth and harvesting facility at Kesterson. This could
possibly reduce the land requirement in the vicinity of Antioch to
about 1,500 acres, or less.
186

A U S GOVERNMENT PRINTING OFFICE 1970 O—4O4-220
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