x>EPA
             United States
             Environmental Protection
             Agency
             Office of Water
             Program Operations (WH-547)
             Washington DC 20460
September 1979
430/9-80-006
             Water
Aquaculture Systems
for Wastewater
Treatment

Seminar Proceedings
and Engineering
Assessment
                                      MCD-67

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                               Disclaimer Statement

This report has been reviewed by the Environmental Protection Agency and
approved for publication.  Approval does not signify that the contents
necessarily reflect the views and policies of the Environmental Protection
Agency or other sponsoring agencies, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
                                      Notes

To order this publication, MCD-67, "Aquaculture Systems for Wastewater
Treatment:  Seminar Proceedings and Engineering Assessment," write to:

                         General  Services Administration (8BRC)
                         Centralized Mailing List Services
                         Building 41, Denver Federal  Center
                         Denver,  Colorado  80225

Please indicate the MCD number and title of publication.

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EPA 430/9-80-006
           AQUACULTURE SYSTEMS FOR
           WASTEWATER TREATMENT:

           Seminar Proceedings and
           Engineering Assessment
                       Robert K. Bastian
                       Sherwood C. Reed

                       Project Officers
                        September 1979

                  U.S. Environmental Protection Agency
                   Office of Water Program Operations
                    Municipal Construction Division
                      Washington, D.C. 20460

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                             EPA Comment


     This report Is one of a series planned for publication by the U.S.
EPA Office of Water Program Operations to supply detailed information
for use in evaluating, selecting, developing, designing, and operating
innovative and alternative (I/A) technologies for municipal wastewater
treatment.  This series will provide indepth presentations of available
information on topics of major interest and concern related to I/A
technologies.  An effort will be made to provide the most current state-
of-the-art information available concerning I/A technologies for
municipal wastewater treatment.

     These reports are being prepared to assist EPA Regional Administrators
in evaluating grant applications for construction of publicly owned
treatment works under Section 203(a) of the Clean Water Act of 1977.  They
also will provide state agencies, regulatory officials, designers,  consulting
engineers, municipal officials,  environmentalists and others with detailed
information on I/A technologies.
                                             Harold  P.  Cahill, Jr.
                                                  Director
                                     Municipal  Construction Division  (WH-547)

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                            SEMINAR PROGRAM COMMITTEE

A number of agencies and groups actively participated In the funding  and
planning of this symposium.  The Individuals representing these groups
on the seminar program committee Included:
                    Cecil Martin, Seminar Coordinator
                    California State Water Resources Control  Board
                    Sacramento, California  95801
Robert Bastian
U.S. EPA
Office of Water Program Operations
Washington, D.C.  20460

Maurice Bender
Argonne National Library (U.S. DOE)
Argonne, IL  60439

Frank Carlson
U.S. DOI
Office of Water Research and Technology
Washlgnton, D.C.  20240

John Colt
Dept. of Civil Engineering
University of California-Davis
Davis, CA  95616

William Duffer
U.S. EPA
R.S. Kerr Environmental Research
  Laboratory
Ada, OK  74820
Tom Inouye
California State Water Resources
  Control Board
Sacramento, CA  95801

Allen Knight
Dept. of Land, A1r and Resources
University of California-Davis
Davis, CA  95616

Sherwood Reed
U.S. Army Corps of Engineers
Cold Regions Research and
  Engineering Laboratory
Hanover, NH  03755

George Tchobanoglous
Dept. of Civil Engineering
University of California-Davis
Davis, CA  95616

Malcolm Walker
California Office of Appropriate
  Technology
Sacramento, CA  95616

B. C. Wolverton
NASA
National Space Technology
  Laboratory
NSTL Station, MI  39529
                                       Hi

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     This publication contains an engineering assessment and  the  pro-
ceedings of a seminar held at the University of California-Davis  on
September 11-12, 1979, on the use of aquatic systems  for the  treatment
of municipal wastewater.  Case studies drawn from throughout  the  United
States are used to illustrate the engineering, design,  operation, and
management of various wastewater aquaculture systems, including projects
involving wetlands processes, aquatic plant processes,  and  combined
aquatic processes.  The potential recovery of energy  and resources is
also considered.

                                  Sponsored by:

                    California State Water Resources  Control  Board
                    U.S. EPA, Office of Water Program Operations
                                             and
                              Office of Research and  Development
                    U.S. DOI, Office of Water  Research and Technology
                    U.S. Department of Energy
                    U.S. Army Corps of Engineers
                    University of California Extension
                              iv

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                                    CONTENTS
Engineering Assessment of Aquaculture Systems for Wastewater Treatment:
  An Overview	
Sherwood C. Reed, U.S. Army Corps of Engineers
Robert K. Bastian, U.S. Environmental Protection Agency
William Jewell, Cornell University
Aquaculture Systems for Wastewater Treatment:  Seminar Overview. .  .  .
Cecil V. Martin and Tommy T. Inouye, California State Water Resources
  Control Board

INTRODUCTION AND OVERVIEW SESSION
Why is California Interested in Aquaculture? 	
W. Don Maughan, California State Water Resources Control Board
Creating a Public Policy Context for Aquaculture Systems 	
Robert L. Judd, Jr. and Malcolm Walker, California Office of Appropriate
  Technology

The Federal Role and Interest by EPA's Construction Grants Program in
  Aquaculture Systems for Municipal Wastewater Treatment 	
James N. Smith and Robert K. Bastian, U.S. Environmental Protection
  Agency

The Use of Aquatic Plants and Animals for the Treatment of Wastewater:
  An Overview	
George Tchobanoglous, Rich Stowell, Robert Ludwig, John Colt, and
  Allen Knight, University of California-Davis

WETLAND PROCESSES SESSION

Session Summary	
William R. Duffer, U.S. Environmental Protection Agency

Wetlands Creation for Habitat and Treatment - At Mr. View Sanitary
  District^ California 	
Francesca C. Demgen, Mt. View Sanitary District
Cypress Wetlands for Tertiary Treatment
Walter R. Fritz and Steven C. Helle, Boyle Engineering Corporation

The Drwnmond Project - Applying Lagoon Sewage Effluent to a Bogs A
  Operational Trial
William M. Kappel, U.S. Geological Survey

Effectiveness of a Wetland in Eastern Massachusetts in Improvement
  of Municipal Wastewater
Donald A. Yonika, IEP, Wayland, MA

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Wetland Tertiary Treatment at Houghton Lake, Michigan	
Robert H. Kadlec, University of Michigan

Engineering3 Energy and Effectiveness Features of Michigan Wetland
  Tertiary Wastewater Treatment Systems	
T. C. Williams and J. C. Sutherland, Williams & Works

AQUATIC PLANT PROCESSES SESSION

Session Summary	
B. C. Wolverton, NASA

Engineering Design Data for Small Vascular Aquatic Plant Wastewater
  Treatment Systems	
B. C. Wolverton, NASA
Development of Hyacinth Wastewater Treatment Systems in Texas,
Ray Dinges, Texas Department of Health
A Water Hyacinth Advanced Wastewater Treatment System	
Dan Swett, Coral Ridge, FL

Water Hyacinth Wastewater Treatment System at Disney World 	
Andrew P. Kruzic, Reedy Creek Utilities Company, FL

Utilization of Water Hyacinths for Control of Nutrients in Domestic
  Wastewater - Lakeland* Florida 	
E. Allen Stewart III, Dawkins and Associates, Inc.

OTHER AQUATIC PROCESSES SESSION

Session Summary	
Allen Knight, University of California-Davis
Frank T. Carlson, Office of Water Research and Technology

Some Ecological Limits to the Use of Alternative Systems for Wastewater
  Management 	
Darrell L. King, Michigan State University
Utilization of Silver and Bighead Carp for Water Quality Improvement ....
Scott Henderson, Arkansas Game and Fish Commission

Treated Sewage Effluent as a Nutrient Source for Marine Polyculture	
John H. Ryther, Woods Hole Oceanographic Institute

The Solar Aquacell System for Primary, Secondary or Advanced Treatment
  of Wastewaters 	
William C. Stewart and Steven A. Serfling, Solar AquaSystems, Inc.
                                    VI

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ECONOMICS, ENERGY. AND BY-PRODUCT UTILIZATION SESSION

Session Summary	
John Colt, University of California-Davis
Maurice Bender, Argonne National Laboratory

Energy Consumption, Conservation and Recovery in Municipal Wastewater
  Treatment - An Overview	
Maurice F. Bender, Argonne National Laboratory
Resource Recovery from Wastewater Aquaculture.
Larry 0. Bagnall, University of Florida
Energy from Wastewater Aquaculture Systems 	
John R. Benemann, Ecoenergetlcs, Inc.

An Overview of the Legal, Political, and Social Implications of Wastewater
  Treatment Through Aquaculture	
Loretta C. Lohman, Denver Research Institute
Economics of Aquatic Treatment Systems
Ronald W. Crites, Metcalf & Eddy
                                           vii

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Engineering Assessment
Overview

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     ENGINEERING ASSESSMENT OF AQUACULTURE SYSTEMS FOR
     WASTEWATER TREATMENT:  AN OVERVIEW

     Sherwood Reed            USACRREL, Hanover, N.H.
     Robert Bastian           US EPA/OWPO, Washington, DC
     William Jewell           Cornell University, Ithaca, NY
BACKGROUND

     The use of aquaculture concepts for wastewater treatment has
received increasing attention in recent years.  Systems studied to
date have included both natural and constructed wetlands, ponds,
raceways and other structures based on various combinations of
aquatic plants and animals.
     In some cases these systems were not optimized for wastewater
treatment since the principal goal was biomass production or the re-
covery of some other beneficial product.  In other cases wastewater
treatment has been the primary objective with byproduct recovery of
secondary importance.  Both types have been studied at the reseatch
level, tested at the pilot scale, and in some cases demonstrated as
a full scale operational system.
     Some of these systems have shown a potential for reducing energy
requirements and operation and maintenance costs.  The incentives
of the Clean Water Act of 1977 provide a strong encouragement for
increased use of such "innovative and alternative" technologies
for wastewater treatment.  However, much of the engineering profession,
which is responsible for the design of municipal treatment facilities,
is not familiar with these aquaculture concepts or their capabilities
and limitations.
     The purpose of this assessment was to define the current status
of aquaculture technologies and to determine if they are ready for
routine use in municipal wastewater treatment.  If they are not ready
for such use the assessment was to recommend procedures for reaching
that goal.  This could take the form of further research, demonstra-
tion, or construction of full scale "innovative*1 systems at selected
locations.
     A team of six internationally recognized engineers was retained
to help conduct the engineering assessment.   They represented a broad
range of expertise and included both practicing consultants and uni-
versity professors.  All were experienced in both research and
design and  were knowledgeable regarding biological systems and

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 innovative technologies.   The team included:

           Mr.  Gordon Gulp
           Gulp Wesner and Gulp.

           Dr.  E.J.  Middlebrooks
           Utah State University

           Dr.  Walter J. O'Brien
           Black & Veatch

           Dr.  Edward Pershe
           Whitman & Howard, Inc.

           Dr.  H.G.  Schwartz,  Jr.
           Sverdrup  & Parcel & Assoc.  Inc.

           Dr.  George Tchobanoglous
           University of California-Davis

     This  team was  organized and  directed by Mr.  Sherwood Reed, USACRREL
 and Mr. Robert Bastian, EPA/OWPO.   The basis for  the assessment was a
 multi  agency sponsored seminar entitled "Aquaculture Systems for Waste-
 water  Treatment" held at  the University of California - Davis, on
 September  11-13,  1979 (EPA 430/9-80-006).  At this meeting research
 scientists, operating system personnel and others presented papers on
 various projects and concepts relative to aquaculture systems for waste-
 water  .treatment.  The final day of the seminar was reserved for direct
 discussion and interchange between the team of engineers and the seminar
 speakers.  Each member of the engineer team then prepared his assessment
 based  on the seminar presentations, supplemented by other Information
 available  with general literature.  The areas addressed were organized
 into three major categories and two team members assigned to each one:

     1.  Wetland processes -  Tchobanoglous & Gulp

     2.  Processes  primarily  dependent on aquatic plants - Middle-
         brooks & O'Brien

     3.  Combined processes where  more than one element has a sig-
         nificant role -  Schwartz  £ Pershe

     This  overview  is based on those individual reports plus a
 review and analysis  of the  available information by the authors of the
overview.  This overview  is organized in three topical areas with
discussion, conclusions and recommendations presented for each.
WETLAND PROCESSES

     For purposes of this assessment wetlands are defined as land

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where the water table is at or above the surface for long enough
each year to maintain saturated soil conditions and the growth of
related vegetation.  These can be either preexisting natural wetlands
(eg. marshes, swamps, bogs, cypress domes and strands, etc.) or con-
structed wetland systems.  Constructed systems can range from creation
of a marsh in a natural setting where one did not permanently exist
before to intensive construction involving earth moving, grading,
impermeable barriers or erection of containers such as tanks or
trenches.  The vegetation that is introduced or emerges from these
constructed systems will generally be similar to that found in the
natural wetlands.
     Studies in the United States have focused on peatlands, bogs,
cypress domes and strands, as well as cattails, reeds, rushes, and
related plants in wetland settings.  A constructed wetland involving
bullrushes in gravel filled trenches was developed at the Max Planck
Institute in Germany.  This patented process has seen limited appli-
cation to date in the U.S.  A number of projects have been developed
in the U.S. in recent years for restoration or enhancement of wetlands.
These use wastewater but are not necessarily optimized for wastewater
treatment.
     Current experience with wetland systems is generally limited
to the further treatment of secondary effluents.  In a few cases
primary effluent has been applied in constructed systems.  The
removal efficiency of typical pollutants are reported as:

                                	       % Removal
                              Natural Wetland   Constructed Wetland
                              (Sec. Effluent)     (Pri. Effluent)

BOD5                               70-96               50-90

SS                                 60-90

N                                  40-90               30-98

P                                  10-50               20-90

     It is assumed that bacteria attached to plant stems and the humic
deposits are the major factor for BOD and for nitrogen removal when
plant harvest is not practiced.  Plant production can play a more
significant role in nutrient removal when harvesting is included.
With respect to phosphorus removal the contact opportunities with the
soil are limited in most natural wetland systems (an exception might
be peat bogs) and a release of phosphorus has been observed during
the winter in some cases.  Based on current experience the land area
being used for natural wetland systems ranges from 30 to over 60
acres per million gallons of wastewater applied.  The surface area
for constructed marshes range from 23 to 37 acres per million gallons
of wastewater applied.
     The major costs and energy requirements for natural wetlands are
the preapplication treatment, pumping and transmission to the site,
distribution at the site, minor earthwork, and land costs.  In
addition to these factors a constructed system may require the instal-
lation of a barrier layer and additional containment structures.

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 Other factors to be considered are potential disruption of the existing
 wildlife habitat and ecosystems in a natural wetland, loss of water
 via evapotranspiration for all wetlands in arid climates, the poten-
 tial for increased breeding of mosquitoes or flies, and the development
 of odor.  The major benefits that can be realized from use of wet-
 lands include preservation of open space, wildlife habitat enhancement,
 increased recreation potential, streamflow stabilization and augmenta-
 tion in addition to wastewater treatment.

 Conclusions

      1.   Wetland systems can achieve high removal efficiencies for BOD,
 SS,  trace organics and heavy metals.   Their potential may exceed  that
 achieved in mechanical treatment systems.   The specific factors
 responsible for these high treatment levels are not clearly under-
 stood at this time.
      2.   Optimum,  cost effective criteria are not yet available for
 routine  design of  wetland type municipal wastewater treatment systems
 throughout  the U.S.   The concept has been shown to be viable and
 should certainly qualify under current EPA definitions as an innova-
 tive technology.
      3.   The use of  constructed wetlands has a greater promise of
 more general application.   These have potential for better reliability
 and  process  control  with a lesser risk of  adverse environmental
 impact.
      4.   The use of  natural wetlands  offers a lesser opportunity for
 process  control  due  to natural  variability within the system.   They
 do however have  considerable potential as  a low cost,  low- energy
 technique for upgrading wastewater effluents,  especially  for  smaller
 communities  located  in areas  of abundant wetlands.   The   prevention
 of adverse impacts on  the  existing,  sensitive wetland ecosystem will
 require  adequate monitoring and appropriate management practices.
     5.   Optimization  of criteria for constructed wetlands  should
 result in much lower land  and preapplication treatment requirements
 as compared  to the use  of  natural systems.
     6.   Health risks  for  wetland systems  are probably not  higher
 than for  conventional  treatments assuming  that  insect vectors  are
 controlled and that harvested materials  are  not  used  for  direct human
 consumption.
     7.   The  potential  for general, routine  use  of wetland  systems,
 particularly  the constructed  type, seems high as  soon as  reliable,
 cost effective engineering criteria are  available.

 Recommendations

     1.  Development of  reliable engineering  criteria will  require
 additional research and  study.  These  efforts should  focus  on con-
 structed wetlands or on  large scale carefully controlled plots in
natural wetlands.
     2.   Several large  scale natural  systems  should be installed in
different geographical  locations, representing the major types of
wetland systems, with  a  range of design  loadings.  These should be

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extensively monitored to obtain "real world" operating information
and to serve as the data base for development of design criteria.
This development should be an interdisciplinary effort involving
engineers, scientists and regulatory agencies.
     3.  A number of constructed wetland systems should be established
concurrently in a variety of geographical settings with other vari-
ables held to the minimum.  This should allow development of region-
ally applicable criteria and eventually of generalized relationships
for universal application.
     4.  Studies of constructed systems should be directed towards
minimizing cost and energy inputs.  Therefore, tests with very
dilute or highly treated effluents should be avoided.  The focus
should be on untreated wastewaters, primary effluents, and on nutrient
removal mechanisms.
AQUATIC PLANT SYSTEMS

     This assessment is based primarily on those systems that use
free floating aquatic plants (macrophytes) for the treatment or
polishing of wastewater.  Most of the information that is available
is limited to the use of either water hyacinths or duckweeds and most
of these data are from water hyacinth systems in warm climates.  These
systems are all constructed and are generally similar in concept to
wastewater treatment pond technology.
     Water hyacinths have been studied in systems treating primary
effluents, as the final treatment cells in multiple cell ponds, and
as an advanced waste treatment step after conventional secondary
treatment.  A field scale system for treating industrial wastewaters
is in operation at the NASA facilities in Bay St. Louis, MS and
pilot scale systems are under study at a refinery in Baytown, TX.
A field scale system incorporating duckweed is located in N. Biloxi,
MS.  Effluent from this two cell pond system is much better than
secondary quality.
     Water hyacinth systems are capable of removing high levels of
BOD, SS, metals, and nitrogen, and significant removal of refractory
trace organics.  Removal of phosphorus is limited to the plant needs
and probably will not exceed 50 to 70% of the phosphorus present in
the wastewater.  Phosphorus removal will not even approach that
range unless there is a very careful management program with regular
harvests.  In addition to plant uptake the root system of the
water hyacinth supports a very active mass of organisms which assist
in the treatment.  The plant leaves also shade the water surface
and limit algae growth by restricting light penetration.
     Multiple cell pond systems where water hyacinths are used on one
or more of the ponds are the most common system design.  Based on
current experience a pond surface area of approximately 15 acres per
million gallons seems reasonable for treating primary effluent to
secondary or better quality.  For systems designed to polish secondary
effluent to achieve higher levels of BOD and SS removal an area of
about 5 acres per million gallons should be suitable.  For enhanced
nutrient removal from secondary effluent an area of approximately 12

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 acres per million gallons seems reasonable.  Effluent quality from
 such a system might achieve:  less than 10 mg/L for BOD and SS,
 less than 5 mg/L for N, and approximately 60% P removal.   This level
 of nutrient removal can only be obtained with careful management and
 harvest to yield 50 dry tons or more, per acre per year.
      The organic loading rates and detention times used for water
 hyacinth systems are similar to those used for conventional stabili-
 zation ponds that treat raw sewage.   However,  the  effluent  from the
 water hyacinth system can be much  better in quality than  from a con-
 ventional stabilization pond,  particularly with respect to:   SS
 (algae),  metals, trace organics, and  nutrients.
      Harvest of the water hyacinth or duckweed plants may be essential
 to maintain high levels of system  performance.   It is essential for
 high levels of nutrient removal.   Equipment and procedures  have been
 demonstrated for accomplishing these  tasks.  Disposal and/or reuse
 of the harvested materials is  an important consideration.   The
 water hyacinth plants have a moisture content  similar to  that of
 primary sludges.  The amount of plant biomass  produced  (dry  basis)
 in a water hyacinth pond system is about 4 times the  quantity of
 waste sludge produced in conventional activated  sludge  secondary
 wastewater treatment.   Composting,  anaerobic digestion  with  methane
 production,  and processing for animal feed are  all technically feas-
 ible.   However,  the  economics  of these reuse and recovery operations
 do not  seem favorable  at  this  time.   Therefore  only a portion of the
 solids  disposal costs  will be  recovered  unless  the  economics  can be
 improved.
      The major  cost  and energy factors for water hyacinth systems
 are construction  of  the pond system,  water hyacinth harvesting and
 disposal operations, aeration  if provided,  and greenhouse covers
 where utilized.   Evapotranspiration in arid climates  can be  a critical
 factor.  The water  loss from a water  hyacinth system will exceed
 the evaporation from a comparable  sized  pond with  open water.  Green-
 house structures  may be necessary where  such water loss and  related
 increase in effluent TDS  are a concern.  Mosquito  control is  essential
 for water hyacinth systems and can usually be effectively handled
 with Gambusia or  other  mosquito fish.  Legal aspects are also  a  con-
 cern.  The  transport or sale of water hyacinth plants is prohibited
 by  federal and  state law  in  many situations.  The  inadvertant  release  of
 the plants  from a system  to  local waterways is a potential concern  to  a
 number of different  agencies.  Water hyacinth plants cannot survive  or
 reproduce in cool waters  so  the concept will be limited to "warm"  areas
 unless climate  control  is provided.  Other floating plants such  as
 duckweed, alligator  weed, and water primrose have a more extensive
 natural range but limited data as their performance in wastewater
 treatment is available.

 Conclusions

     1.  Aquatic  plant  systems using water hyacinths can achieve high
 removal efficiencies for BOD, SS,  trace organics, heavy metals and
nitrogen.  The potential can equal, and may exceed that achieved in
mechanical treatment systems.

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     2.  Water hyacinth systems are ready for routine use in municipal
wastewater treatment, at least within the geographical range where
such plants grow naturally.  Reliable engineering criteria are avail-
able for the design of systems for treating primary effluent, for up-
grading existing systems, for advanced secondary treatment and for
full AWT.
     3.  It is unlikely at this time that the costs of plant harvest
and processing will be completely offset by the value of useful
products (eg: animal feeds, compost, biogas, etc.).
     4.  Water hyacinth systems may be technially feasible even in
northern climates if operated in a protected environment or run as
a seasonal activity.  However, this has yet to be shown to be cost
effective for climatic zones where the plants cannot exist naturally.
     5.  Nutrient removal in water hyacinth systems is more complex
than uptake by the plant alone, but the responsible mechanisms are not
yet clearly defined.
     6.  Duckweeds are a more cold tolerant plant than the water hya-
cinth.  Wastewater treatment experience with these plants is limited and
engineering criteria for routine design are not yet available.
     7.  Many other cold tolerant aquatic plants exist but their
potential for wastewater treatment has not been evaluated.

Recommendations

     1.  Further optimization of water hyacinth system design is
possible.  This should include:  tracer studies of existing systems
to determine actual detention time, the full range of organic and
hydraulic loadings that may be possible, and on mass balances of water
and pollutant materials.
     2.  Additional study is needed to establish optimum plant har-
vesting and utilization techniques and to evaluate alternative methods
for removing additional phosphorus with water hyacinth systems.
     3.  A study should be undertaken to evaluate the potential for
water hyacinth systems in cooler climates.  This should include energy
requirements and overall cost effectiveness.  If results of the paper
study are favorable a pilot testing/demonstration program might be
considered.
     4.  Research and demonstration projects should focus on the use
of duckweed and other plants (especially the more cold tolerant types)
for wastewater treatment.  These efforts should include:  removal
kinetics for pollutants as a function of detention time, temperature,
plant type, etc.; and the effect of system configuration, season,
benthic materials, and plant harvest on degree of treatment.
COMBINED SYSTEMS
     For purposes of this assessment, combined systems are defined
as treatment systems derived from aquaculture concepts that either
contain more than one active aquaculture component in a single unit
or that are combined with other aquaculture or conventional units
to form a process.  An example of the former are the experiments at
Woods Hole Oceanographic Institute involving a number of different

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 marine organisms.   Examples of the latter are the Solar Aquacell
 System at Hercules CA, the marsh/pond systems studied at Brookhaven
 National Laboratories, LI, and the use of fish in the final cells of
 wastewater stabilization ponds in Arkansas.
      Based upon the results of experimental  and pilot testing work to
 date, it is clear that both agricultural and municipal wastewater in
 treated or partially treated forms can be used in fish culture and
 other aquatic protein or biomass production  systems.   Fin fish such
 as Tilapia, carp,  gamefish and bait minnows  have been very successfully
 raised in and harvested from wastewater stabilization pond systems.
 Daphnia, shellfish, vascular plants, algae,  and other aquatic organisms
 have also been successfully produced and harvested.   However,  it is
 not clear that such systems can be optimized for both waste treatment
 and protein production purposes at the same  time.
      Since each concept is unique it is not  possible  to present  a
 general summary of performance for "combined systems".   The potential
 for routine use must also be discussed on an individual basis.   For
 that reason,  the examples cited above are discussed individually
 below.   Discussion of this limited number of projects is not  intended
 to imply that there are not other viable systems or combinations,  but
 space limitations  have precluded an exhaustive presentation.   It is
 hoped that the assessment of these few projects will  provide  some
 general indications or trends regarding combined systems.

           Marine Polyculture
           Woods Hole Oceanographic Institute,  MA

      This  pilot scale,  continuous flow system was designed  to  remove
 nitrogen from secondary effluents and at the same time  culture marine
 organisms  that have commercial value.   The secondary  effluent was  di-
 luted with seawater and introduced to a system that consisted  of
 shallow algae ponds,  followed by aerated raceways containing  stacked
 trays of shellfish and  then into a final unit  for seaweed production.
      The algae ponds  were designed as the  initial nitrogen  removal
 step.   The projected  area requirement for  this  step was  comparable
 to  that  required for  conventional facultative  stabilization ponds.
 Problems encountered  at this  step included inhibition of algae produc-
 tion  by  particulate matter  in the secondary  effluent, seasonal varia-
 tion  of  algae species  and protozoan predation.   Some algae  species
 proved  detrimental  to  shellfish  culture  and  the  problem  of  algae
 species  control was not resolved.   The  shellfish experiments with  the
American oyster and hard  clams  indicated slow  growth rates  and high
mortality.  The last  unit  contained  seax^eeds  for final nutrient  removal
with vigorous  circulation to  keep  the  seaweed  in suspension.  Overall
nitrogen removal was  89%  with  all  components  functioning but the
overall  cost  effectiveness was questionable  since the shellfish  pro-
duction  unit was not  successful.   It  appears  that nitrogen  removal
could be achieved by just a seaweed  unit without the preliminary
algae and  shellfish steps.

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          Solar Aquacell System
          Hercules, CA

     This system was developed through bench and pilot scale testing
of combined aquaculture and conventional technologies.  A full scale
system has been recently constructed at Hercules, CA.  The system
consists of a two cell anerobic unit, followed by an aerated cell
followed by a final aerated cell covered with water hyacinths and
some duckweeds.  An internal feature of all cells are buoyant plastic
strips to serve as a substrate for the growth of attached organisms.
The entire system is covered by a  (double layer polyethylene, air in-
flated roof) greenhouse structure.  Aeration is provided by submerged
tubing and is low to moderate in intensity.
     Performance results are not yet available from the Hercules
system.  Based upon pilot units, tested elsewhere, it was predicted
that final effluent quality would be 5 mg/L or less for BOD and SS
if 5 days detention time is provided in the final water hyacinth cell.
The buoyant plastic webbing, with its attached growth is credited with
80% or more of the removal achieved in this cell.  Removal of total
nitrogen was about 50% in the same 5 day detention pilot tests and the
water hyacinth plants accounted for only 10% of that removal.  Phos-
phorus removal was relatively low  (1-2 mg/L removed in 5 days) since
the aquatic plants and organisms are the only pathways available.
     The Solar Aquacell concept requires a regular schedule of water
'hyacinth harvest, processing and disposal.  The Hercules, CA system
also includes ozone disinfection arid a sand filter for final polishing
to maximize reuse potential for the effluent.  A functional analysis
of the various elements and components in the system seems to indicate
that the major portion of BOD, SS, and nitrogen removal is provided
by the anaerobic cells and by the attached biomass on the plastic
webs in the aerated cells.  The major function of the water hyacinths
and duckweeds may be in shading the water surface to prevent algae
growth.  The use of the buoyant plastic web in an aerated pond is a
novel and innovative application.  The system can then benefit from
both suspended and attached organisms and the presence of the webs
should reduce or eliminate short circuiting of flow in the system.
                            «v
          Marsh-Pond System
          Brookhaven National Laboratory, NY

     This 20,000 gpd, pilot unit included an aerated holding cell with
2 1/2 days detention time followed by a 0.2 acre constructed marsh
followed by a 0.2 acre unaerated pond with a partial cover of floating
duckweeds.  Effluent from the pond was then applied to the land at a
forested site in a groundwater recharge experiment.  This assessment
is not concerned with the land application step or a parallel experi-
ment involving overland flow ahead of another marsh/pond combination.
     The system was studied for several years (1975-1978) and received
a wide variation of flow and pollutant loadings.  Effluent recycle from
the pond to the head end of the marsh was conducted frequently to
maintain flow in the system.  However, neither this recirculation or
the preaeration were controlled in a regular manner.  The system was
operated on a year-round basis in  the relatively temperate winter
climate on Long Island (average air temperature below freezing 5 months

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 of the year and the water temperature in the system was 2°C or less
 4 months of the year).  Reported effluent characteristics averaged
 for the period 1975-1977 were:

                                    mg/L           % Removal

           BOD                       21                89
           SS                        42                91
           TKN                       11                63
           Total P                    2                66

      The parallel overland flow marsh/pond produced slightly better
 results in all categories.   Neither system during the period under
 discussion could consistantly meet secondary treatment standards for
 suspended solids.   Both however, provided an excellent,  and probably
 cost effective preapplication treatment for the groundwater recharge
 operation.   It is not possible from the published data on the Brook-
 haven studies  to develop optimum engineering criteria for rational
 design since detention times, mass balances, effect of configuration,
 season,  plant  type,  etc.  were not quantified.

           Fin  Fish in Stabilization Ponds
           Benton,  Ark.

      There  are numerous examples of successful  fish culture  operations
 with  a variety of  species,  in cooling  ponds  and wastewater stabiliza-
 tion  ponds.  This  assessment  will focus  on  studies  in Arkansas where
 the  effect  of  fin  fish on water quality  improvement was  evaluated
 in controlled  experiments.
     The preliminary  experiments compared parallel  3 cell  stabiliza-
 tion ponds  receiving  equal volumes  of  the same  wastewater  (BOD 260
 mg/L,  SS 140 mg/L).   The  cells in one  set were  stocked with  silver,
 grass, and  bighead carp while the other  set  received no  fish
 and was operated as a conventional  stabilization pond.   The  compari-
 tive study  continued  for  a full annual cycle.   Results indicated
 generally similar  performance of the two systems but  the fish culture
 units  consistantly performed  somewhat better than the  conventional
 pond.  For  example, the effluent BOD from the fish  system  ranged
 from about  7 to 45 mg/L with  values less than 15 mg/L  obtained more
 than 50% of the time.   The conventional  pond system had  effluent BOD
 ranging from 12 to 52 mg/L with values less  than 23 mg/L about 50%
 of the time.   Suspended solids  were very similar in  the  effluents
 for both systems except in July when the concentration was about
 110 mg/L for the conventional  pond  and 60 mg/L  for  the fish system.
     The second phase of  the  study  was conducted at  the  same location
with the same wastewater.  The  six  pond  cells were  all connected in
series and a baffle constructed  in  each  to reduce short  circuiting.
Silver carp and bighead carp were stocked in the  last  four cells and
additional grass carp,  buffalofish  and channel  catfish in  the final
cell.  No supplemental  feed or  nutrients were added  to the fish culture
cells.  Estimated  fish  production after  8 months was over  3000 pounds
per acre.
     Effluent quality steadily  improved  during passage through the six
                              10

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cell system.  The BOD removal for the entire system averaged 96% for
the 12 month study period.  About 89% of that removal was achieved in
the first two conventional stabilization cells.  Removal of suspended
solids averaged 88% in the entire system with 73% of the removal
occurring in the first two conventional stabilization cells.  It is
not clear wether the fish or the additional detention time or some
combination is responsible for the additional 7% BOD removal in the
final 4 fish culture cells.  The final average effluent concentration
of about 9 mg/L is typical for six cell conventional stabilization
ponds of comparable detention time.  It seems very likely that the fish
contributed significantly to the low suspended solids value in the
final effluent (17 mg/L) via algal predation.  A value two or
three times that high might be expected for conventional stabilization
ponds.

Conclusions

     1.  Finfish were effective in providing further treatment in
wastewater treatment ponds.  Their major role seems to be suspended
solids control for final polishing.
     2.  It does not appear that aquaculture components in "combined
systems" can be optimized for both protein or biomass production
and waste treatment in the same unit.
     3.  Systems involving higher forms of animals seem to be less
efficient (at waste treatment), require more land area, or are more
difficult to control than systems primarily based on plants.
     4.  There is sufficient information available to install fish
culture units in the final cells of stabilization ponds.  There is
not enough information available to permit routine design of such
units for wastewater treatment.  Specific removal rates and growth
rates and O&M requirements under different environmental and waste-
water conditions need further definition.
     5.  Most of the other combined systems discussed here are
either in the exploratory or developmental stage and rational criteria
for their routine design are not available at this time.

Recommendations

     1.  Development of new concepts in the use of polyculture or
combined systems for wastewater treatment should be strongly encouraged.
The focus should be on high rate, low energy combinations involving
plants and possibly animals or mechanical elements.
     2.  Further study and evaluation of combined systems is necessary.
This should focus on identifying critical components and on the de-
velopment of engineering design criteria.
     3.  The most promising concepts should be tested in a variety of
geographical settings to define removal kinetics and develop criteria
for a range of wastewaters and environmental conditions.  This would
include the degree of thermal protection and energy required for opera-
tion in cooler climates.
     4.  Studies should focus on the health effects of the direct use
of animal protein harvested from these systems in human foods.  Studies
                                      11

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should also consider development of alternative products from the
animal protein.
REFERENCES

     References are not included in this Overview since it was drawn
from the six engineering assessments published elsewhere ("Aquaculture
Systems for Wastewater Treatment:  An Engineering Assessment";
EPA 430/9-80-007; June, 1980) and from presentations at the Davis, CA
aquaculture seminar.
                              12

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Introduction and Overview
Session

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AQUACULTURE SYSTEMS FOR WASTEWATER TREATMENT:  SEMINAR OVERVIEW

Cecil V. Martin, Seminar Coordinator and Tommy T. Inouye
  California State Water Resources Control Board,
  P. 0. Box 100, Sacramento, Calfornia  95801
     Our real interest in wastewater aquaculture started about three
years ago when a number of requests were received asking the California
State Water Resources Control Board to fund aquaculture type treatment
facilities under the Federal Water Pollution Control Act (PL 92-500).
The Clean Water Act of 1977 (PL 92-217) also encourages an examination
of aquaculture treatment as a facet of innovative and alternative (I/A)
technology.  The California State Water Resources Control Board (State
Board) staff was requested to evaluate the state-of-the-art and to
advise the State and its Regional Boards on a course of action that
should be taken that would be in the best interests of the people of
the State in regards to the utilization of aquaculture technologies as
well as the expenditure of the grant funds.

     In our discussion with the federal EPA and others, we discovered
that a similar need existed for the entire United States.  As a result
this seminar was born.  It was sponsored by the State of California
and a number of interested federal agencies.  It brings together current
projects and workers in the field of wastewater aquaculture.  These
proceedings in effect represent the current state-of-the-art on the
topic as presented by the various authors and speakers.  A unique fea-
ture of the seminar was the development of an independent engineering
assessment of the material presented.  The assessment can be found
elsewhere in this document.  The reader is encouraged to read the
original papers, correspond directly with the authors, and develop a
personal assessment as to the status of wastewater aquaculture
technology.

     Technical sessions at the seminar were organized in four major
categories: Wetland Processes, Aquatic Plant Processes, Polyculture or
Other Aquatic Processes, and Economics, Energy and By-Product Utiliza-
tion.  The major emphasis was on pond-oriented and natural marsh systems
since this is where most of the research and development efforts have
been focused to date.
                                       15

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      As indicated by the title of  the seminar,  the major  purpose was
 to consider the potential of  aquaculture  technologies  for wastewater
 treatment  and not as food and fiber production  systems, as waste
 disposal alternatives,  or as  mitigation measures  of other environmental
 impacts of a project.   Several polyculture  and  combined aquatic systems
 in various stages of development or demonstration were described.  While
 systems of this type need further  development,  they would seem to offer
 the greatest promise of combining  food production with wastewater treatment,

      The presentations  at the seminar served  to clearly define the
 benchmarks of our current knowledge regarding wastewater  aquaculture.
 These included:

           Aquaculture is being used for all phases of  wastewater
           treatment  from primary through  advanced wastewater treatment.
           Many current  systems use  aquaculture components for removal
           of specific pollutants such as  BOD, SS, metals  or nutrients,
           or are  designed as  a polishing  step after conventional forms
           of treatment.

      -    Aquaculture is an alternative wastewater treatment technique
           whose time has come.

           Aquaculture systems  can be  energy efficient, economical, and
           environmentally enhancing under appropriate  conditions.

           Aquaculture is not  a universal panacea  for wastewater treatment.
           There are still  questions and limitations on applications.   The
           basic concepts have  been  demonstrated,  but further work is
           necessary for  process optimization and  to define the acceptable
           ranges  (e.g.,  geographical  difference, wastewater types,
           application rates,  etc.)  for routine use of  the concepts.

          Aquaculture systems  that were discussed at the seminar appeared
           to be cost effective, but in some cases they may be labor
           intensive at an  unskilled level.

          The  terminology  involved  in wastewater aquaculture need
           clarification  to avoid confusion and to more clearly define
           the major purpose of a particular project.   For example,
          wastewater has been used  in aquaculture systems for the
          production of  food and fiber, but these same systems were
          not necessarily optimized for wastewater treatment.

     The presentations at the sminar also helped define what we still
need to know and the opportunities for further optimization.   These
included:

          Further definition on the limits of hydraulic and  pollutant
          loadings and the related reaction kinetics  is needed  for
          process optimization.  This would include  the influence  of:
          harvesting, temperature,  light,  pH,  humidity, TDS,  plant and
          organism types, system depth and configuration,  and  pollutant
          removal efficiencies.
                               16

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          A more precise definition of the fate of metals,  toxic
          organics, pathogens and potential disease or nuisance  vectors
          such as mosquitoes, will assist in selecting aquaculture
          concepts and the reuse options for final effluent and
          harvested products.

          Routine operation and management procedures for full scale
          aquatic systems need further definition.  This would include
          operator training and certification requirements.

          Legal and institutional restrictions limit the use,  the sale,
          and the transport of various aquatic plants and fish,
          especially nusiance, pest and exotic species.  Study is
          needed to define the actual impact if these escape from a
          treatment system, or to develop an escape proof,  fail-safe
          system, and/or to use alternative plants and aquatic organisms
          for treatment.  The geographical range for application of
          aquatic systems may be limited without such work.

          The potential for increased benefits exists, but  will  require
          further work for definition of limitations and procedural
          methodology.  For example, these would include: use of plant
          biomass for methane or other energy production, utilization
          of harvested animal protein, and recovery of purified  water
          vapor in greenhouse or covered systems.

     Coordinating this first seminar of which we hope will  be a  continuing
biannual information exchange program on wastewater aquaculture, has
been a very enlightening and pleasurable experience.  We were pleasantly
surprised at the interest this topic has generated.  The meeting was
attended by approximately 250 people from throughout the nation  and
several foreign countries representing many interests and disciplines.

     We commend the program moderators and speakers for a job well done.
They kept the seminar on its tight schedule, and the papers as a whole,
were well presented and thorough.  The majority of attendees found them
interesting enough to stay through the last presentation!

     We would like to extend our thanks especially to Ms. Allison Gotez
and Mrs. Shirley Bell of the University of California, Davis,  Conference
and Campus Services for their assistance.  Without their patience and
tolerance during our mad scramble to organize this seminar, we would not
have attained the high degree of success, that is evident by the papers
reproduced in this publication.
                                       17

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     WHY IS CALIFORNIA INTERESTED IN AQUACULTURE?

     W. Don Maughan, Chairman, California State Water Resources
       Control Board, P.O. Box 100, Sacramento, CA  95801
INTRODUCTION

     The people of California are committed to the cleanup of its
waters and to the maintenance of water quality in the face of
increasing population growth, as shown by its statutes and voter
approval of $875 million of Clean Water Bonds.  We want to be
innovative about how we achieve high water quality because conven-
tional wastewater systems have substantial monetary, environmental
and energy costs.

     From data on aquaculture treatment systems, use of these systems
in some cases in California appears highly promising.  Land avail-
ability and climate factors seem particularly suitable for use of
these systems.  California also has the scientific capability for
rapid research and development of these systems from inception to
implementation.

     In the immediate future, we see the potential for application of
these systems to small communities.  Under the 201 construction grant
program, there are approximately 350 small unsewered communities on
the current priority list.  They are prime candidates for systems
which are economical to build and operate.

     Further into the future after Federal 201 and Clean Water Bonds
have been used to bring all our major population centers to at least
secondary treatment levels, aquaculture wastewater treatment systems
could be used to expand the qapacity of some of the existing
facilities to meet the needs of increased populations.  It is expected
that the lack of State or Federal funding of capital expenses will
mean that plants which may be more labor-intensive but less costly
to build than those presently in operation, will become more
attractive.

     California is strongly interested in reuse and reclamation of
treated wastewaters which would be furthered by aquaculture systems.
                                      19

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      In October 1977,  the State Board  established  an Aquaculture
 Section in the Division of Planning  and  Research.   The  Section's
 responsibility is  to  evaluate and  demonstrate  the  use of  aquaculture
 as a wastewater treatment technique  and,  where practical,  to offset
 the cost of treatment  to consider  the  culture  for  production of
 aquatic organisms  for  sale.   Although  the primary  interest of the
 Board is in wastewater treatment,  disposal,  and reuse,  all aspects of
 aquaculture and mariculture technology are also included  in the
 Board's program as it  relates to beneficial  use of waters  of the State
 and are therefore  of  interest.

      In regard to  wastewater treatment,  an aquaculture  center at U.C.
 Davis has been established recently  to look  at the wastewater treat-
 ment processes.  In addition, the  State  Board  staff have been wording
 closely with the City  of San Diego for preparation of a workplan for a
 1  mgd pilot project using water hyacinths.   State  Board staff have
 also worked very closely with the  City of  Arcata during the development
 of a pilot project to  demonstrate  the  feasibility  for using marshes
 for wastewater treatment with additional  benefits  for wildlife.
 Construction of  this project is expected  to  begin  this month.

      In the area of reuse and general  aquaculture  and mariculture
 technology,  the  State  Board  has established  a  project at Firebaugh to
 examine the reuse  potential  of  irrigation  drain water for  aquaculture
 of invertebrates and fish.  Preliminary results  of  these studies have
 been extremely encouraging but  the final  evaluation will not be com-
 pleted  until  July  1980.   Before aquaculture  can be  fully accepted, the
 engineering and  health communities must be convinced  that  these
 systems work  in  terms  of  treatment capability  and  reliability^ and
 that  their  operation is within  the capabilities  of  the average plant
 operator.   In  the  past,  the  lack of consistency in  reporting treatment
 parameters  among researchers  and serious omissions  in data have
 hindered  acceptance.   Further pilot-scale  facilities  with  extensive
 control  features for operational flexibility have not been used in the
 past  to determine  environmental  tolerances, production rates and
 changes in water quality  associated with the test organisms.  It is
 hoped that  this  seminar will  help  future projects to  overcome these
 shortcomings  in  the earliest  practicable  timeframe.

     More research  is  still  indicated.  Additional work with aquatic
 plants must be conducted  in  order  to evaluate  the potential of extending
 the geographical and climatic areas for the use  of  these systems as
well as the potential  for  increased reliability  under controlled
 environmental cconditions as  afforded by greenhouse covers.  Also
 developmental research should include utilization of other aquatic
macrophytes  with restricted  ranges for special application.  Up to
 this time research has generally emphasized those species with wide-
 spread distribution.
                              20

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     Clearly, much information has been developed and will be presented
during the next two days.  More data will have to be developed in
order to enable decision-makers to have confidence in aquaculture.

     It is our hope that this seminar will be more than an interchange
of technical informtion, more in the sense that all advocates of
aquaculture find the best and quickest way to put this kind of treatment
on a solid foundation so that elected and appointed officials can make
commitments to the process.
                                      21

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     CREATING A PUBLIC POLICY CONTEXT FOR
     AQUACULTURE SYSTEMS

     Robert L. Judd, Jr., Director, Office of Appropriate
      Technology, State of California, 1530 - 10th Street,
      Sacramento, CA  958lU

     Malcolm Walker, Environmental Health Engineer,
      Office of Appropriate Technology, State of
      California, 1530 - 10th Street, Sacramento, CA
      958lU
     If aquaculture systems for wastewater treatment are to be adopted
on a meaningful scale, it is necessary to set goals and orient re-
search efforts toward answering questions that policymakers must ask
before making investments of public funds.  Although work in progress
is encouraging, there is a disquieting lack of context that may con-
strain future development.  The current situation in California as
described here exemplifies both the promise and problems inherent in
aquaculture system implementation.

                        *#****#***#*###*#*
     I'd like to offer some perspectives on aquaculture and the
implementation of alternative methods both here in California and in
other areas.  My comments will address the state-of-the-art from a
policy perspective, and then suggest some directions for the future
that could accelerate development.
     Many of you in the audience are either students planning to work
in aquaculture as engineers or biologists, or are already working as
professionals in the field.  The perspective that I hope to share
with you sheds light on how the decisions are made for funding pro-
jects, and how public policy itself is implemented.  They reflect the
kinds of questions that are asked by the Governor and by the State
Department of Finance as they consider whether or not to make invest-
ment decisions in various forms of alternative technologies.
     When I was asked to be on this panel I sat down and asked myself
a few questions, then I decided to call a number of experts around
the country to raise the questions with them.  My inquiry began by
asking, what do we get from what we already have?  Where are we going?
What is the context for the aquaculture development that currently
                                      23

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 exists?   And I found as  I called around that  everywhere  it  is about
 the same.   California is seen as the  leader but  there  are obviously
 good projects in other states as well.   The interesting  fact is that
 in most  cases they are run by individuals  vho are  leaders rather than
 by institutions that have taken the lead.
      As  I talk I'd like  to focus a bit  on  the realities  of  what's
 going on,  and to point out that the reality is less encouraging than
 common perception.   Some of the questions  that come up are  as follows:
 How do we  implement  the  technology itself?  Right  now  the focus seems
 to be primarily on basic research.  Aquaculture  and wastewater treat-
 ment are essentially an  "ad-hocracy"  rather than a bureaucracy at this
 point.   As a scientific  discipline and  as  a practical  matter, it lacks
 organization.   It  more closely resembles a  number  of random points
 than a series of connected points  on  a  line that has some direction.
 I  see the  situation  as one that  both  reflects the  state-of-the-art
 while at the same  time indicating  a need for  a joining of forcer; and
 a  focus  to decide  where  this  research is going, to set targets, to set
 goals.   What is  the  public policy  outcome  of  these various  projects
 in the state?   Do we have  a target of treatment of a certain amount
 of wastewater by a certain period  of  time?  Do we  have cost targets?
 They don't seem  to exist  right  now.
      In  talking  with various  individuals in research or  program admin-
 istration,  I find a  common feeling that we're not  sure that the right
 questions  have been  asked,  that  we have an  answer  without adequately
 defining the  question  at hand.   Nevertheless, experimentation goes on.
      For example, the  Office  of  Appropriate Technology and  the State
 Water Resources  Control Board worked  together to implement  the experi-
 mental aquaculture center  here at the University of California at
 Davis.  Where is that  going?  What's  the function  of it?  There will
 be  nearly half a million dollars spent on aquaculture  research here
 in  Davis in the  next three years.  What return can the government
 expect on  its investment?
     Preliminary cost  and  energy analysis show aquaculture to be very
 cost  effective when  compared with a. conventional wastewater treatment
 facility of  1 million  gallons a  day.   Capital cost comparison for an
 TMGC plant between aquaculture,  primary and water hyacinths and chlo-
 rination, and conventional treatment, activated sludge and  chlorina-
tion, show a cost saving of $682,500  or k2  percent.  Operation and
maintenance  cost show  a further  saving of $22,500/yr.  while energy
 savings  for  aquaculture over conventional  treatment is  1.03 x 10°
kWh/yr. or U? percent.  Such  savings  are substantial for small commu-
nities where the wastewater treatment facility may be the largest
 energy user  in the community.  These  analyses, though encouraging,
 are  dependent on good  design  criteria, efficient harvesting methods
and  ease of operation.  If we are to  stay in this business then we
must  strive to accomplish the goal of developing a cost effective and
 energy resourceful wastewater treatment system.  Aquaculture is such
 a  system, but will require initiative and direction.
      Other questions arise:  What can be done to speed and focus the
work  to  ensure that  there  is  a public value above and beyond research
 successes?  Whose realities are we dealing with?  That of the biol-
ogist, the engineer, the city manager who faces rising costs in
treatment programs and discharge problems?  The consensus is that
                               24

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there is a lack of momentum, that if the work remains as it currently
is — with a few good people doing experimental projects — that our
effort will not be enough.  We will have foregone opportunities that
greater advocacy would have brought us, and we will simply end up three
or five years from now at about the same level of non-implementation
unless a policy focus and a time-related set of goals is developed.
There are numerous barriers that have to be addressed.  Legal con-
straints obviously exist.  The economic analysis of alternative treat-
ment needs refinement.  Life cycle cost methods in this aro in
many instances not of a quality to convince a public body to make an
investment.  There are certainly parochial interests involved, such
as the interests of regional boards versus the State board.  There
remains a great degree of uncertainty regarding the value of the tech-
nology or the state of development of the technology.  Another conflict
exists — the R&D sector versus the regulatory sector — in which each
has different interests.
     I want to talk a moment about one group that cut through some of
these questions.  Many of you have heard of it, and some of you may
have visited the facility that is now under construction in the town
of Hercules, California.  Hercules is a small town currently having a
population of about ^,000 people.  It's about thirty miles north of
San Francisco.  In 1975, the city adopted a general, plan which called
for planned growth in an ecologically sound manner.  Their plan pro-
jected a population of 20,000 in 1990, up from '4,000 in 1979.  Based
on this projection, Hercules faced a problem of what to do with their
additional wastewater.  Presently, their wastewater flows to an
adjacent city's wastewater treatment plan.  That plan doesn't have
the capacity to handle the future additional load that will be imposed
by this growth
     Hercules therefore was faced with the choice of investing in an
enlargement of the adjacent plant or building their own plant.  They
opted for building their own plant.  Because they decided to grow
faster than the allowable rate of two percent which is set by the Air
Resources Control Board in California, the city was not eligible for
State and federal wastewater treatment grants.  The only way the city
could grow at their proposed rate would be to fund their own system.
They then faced choosing a wastewater treatment system that would
both meet their needs and State discharge requirements.  Many treatment
systems would meet the State requirements but few were ecologically
sound, low cost, and resource- and energy-conserving in the local con-
text.  Hercules eventually chose an experimental system from Solar
Aquasystems which met their needs arid the State requirements; and, at
the same time, provided options for wastewater reclamation and biomass
utilization.  The Solar Aquasystem sewage treatment plant is being
constructed with completion of the first module expected in the late
fall of this year (i960).  Construction costs are expected to run
about $3.5 million for a 2-million-gallon-per-day plant, or $2 per
gallon compared to $;i to $6 per gallon for equivalent water quality
from an advanced wastewater treatment facility.  Operation and main-
tenance costs run considerably lower.  Depending on the system per-
formance data, reclaimed water may be a revenue-creating commodity.
                                       25

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      The  important  issiie  to recognize  here  is that  city officials were
 willing to take  a risk.   That  they were willing to  play what we used
 to call "guts tall" — they'd  just get out  there, take some calculated
 economic  risks and  some political  risks to  move the technology ahead.
 I  suggest that we need more of that in the  State, and that we can have
 it if we  give our representatives  better  information on which to base
 their decisions.
      The  present complacent attitude in which aquaculture is mired is
 an unnecessary frustration.  Why sit back and watch?  The hesitancy
 on the  part  of the  bureaucrats —  if it works we can claim a victory;
 and if  not,  we can  back off from alternatives — is a disservice to
 those of  you whose  visions  and professional lives are invested in this
 subject.   If you believe  in this technology, organize yourselves and
 seek  better  support  from  the policymakers that provide you. the tools
 (dollars  and facilities)  to make progress.  But, as you speak out in
 your  self-interest,  remember that  you  incur a greater responsibility
 to prove  the utility and  cost-effectiveness of the  systems you propose.
      Let  me  move from Hercules to  the UC Davis wastevater aquaculture
 center.   I mentioned before that there were barriers.  I'd like you to
 understand how bureaucracy works.  Much to the credit of the State
 Board and to the University, they  adopted late in 1977 the concept of
 developing an aquaculture wastewater research facility on the campus
 here.   It went through the budget  review process and was approved in
 midsummer of 1978.    It was provided money for laboratory equipment,
 personnel, and for a building in which to do the experiments.   About
 $375,000  was allocated for the first year, with $150,000 or so for
 each  of the two following years.    It has taken until late spring of
 this year, almost a  full year, to  negotiate overhead rates and to push
 a  contract through the University  and through the Board.   Now, seven-
 teen months after the money was approved for the facility, we still
 have no facility.
     This  is a problem, fairly typical I suppose, that many people will
 face in changing the status quo.    I'd have to say that the difference
between the wishful thinking and the reality is that the bureaucratic-
 slowness drains the momentum from projects.  In this case, it  looks
 like the project will not get off the ground until mid-1980.   If there
 is to be an incentive and a real commitment rather than rhetoric from
the University and from the State Board,  it is important to break
through the log jams on this project, to move faster and to develop a
 sustained momentum.
     While preparing this speech,  I talked to people in Florida,
Washington, and many other states.   I say, "Well,  what's  going on in
 other states?"  And they say, "Well, not  much; we're watching
California."  California is seen as the leader.   California's  Water
Resources  Control Board is the best in the country;  there's no doubt
 about that.  Also,  the work that is being done at  UC Davis by  the
 scientists here is absolutely top quality.
     Yet,  if California is the leader; if, in fact,  we are setting a
model for others to  follow, it is important for all  of us  to under-
 stand what is the quality and nature of that leadership.  What  really
 is the position of the Board itself regarding aquaculture and  what
 could they do that they are not already doing?  I'd  like  to give  you
                               26

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a sense of what has gone on there.  On March l6,  1978, the Board made
its first resolution concerning alternative vastevater systems.   Here's
vhat it said:

    "Therefore be it resolved that the State Water Resources
     Control Board does hereby announce its support and en-
     couragement to greatly increase effort and emphasis on
     the use of alternative wastewater disposal systems and
     that the Board adopt the action plan for wastewater
     management systems investigation arid implementation in
     California."

     Fine.  Well done.  They have a very good work plan and they have
a small staff working in aquaculture.  Recently,  however, when the
issue of alternatives were brought before the Board on June 21,  1979,
the resolution was refrained.  Listen to the difference in the language:

    "Therefore be it resolved that the State Water Resources
     Control Board does hereby reaffirm its support and en-
     couragement to increase efforts and emphasis on the
     use of alternative wastewater systems; that the State
     Board shall continue to sponsor research and demonstra-
     tion projects to advance the knowledge and implementation
     of these systems; that the regional boards are encouraged
     to issue either waste discharge requirements for experimen-
     tal systems or approve a general local agency experimental
     program for alternative systems.  The State Board is
     available for developing alternative programs regardless
     of the options selected, experimental alternative systems
     are encouraged to be supported."

     A strong reaffirmation.  Unfortunately, that resolution  was
tabled.  It was not acted upon.  The action plan that currently
exists within the Board, the plan that gives greater stress to
aquaculture than has ever been made before was also not acted upon
at this time.  Now that's not meant as a real heavy criticsm  of the
Board.  I'm confident that they will act on it.  The important point
though is the act and not the good intention.  When you table reso-
lutions, you essentially take the wind out of the sails of the
projects themselves.
     I have a few comments about education.  It seems to me that if
we are going to develop advocates for alternative treatment systems
we also have to train people to understand them better.  We have to
reduce the amount of uncertainty felt by staff members of the
regional boards.  That can be done through training.  The same would
hold for training of members of staff at headquarters.  Training
opportunities are very limited at this point.  'They could be  much,
much stronger.
     I have a number of recommendations as I close.  The new Board,
as it will be constituted when the fifth member is appointed, has a
perfect opportunity to speak out in support of practical innovation
and reaffirm its commitment to the une of alternative technologies
in wastewater treatment.  Working with practitioners in the field
                                       27

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and with regional boards, they also have the opportunity to develop
a context to set goals for aquaculture-based treatment facilities,
and to work together to achieve successful implementation.
     Education should receive higher priority, and our State should
provide continuing services to other states vhich wish to make a
marriage between policy decisions and engineering and technical ex-
perimentation that's been done in the field.
     In the discussion of the long-range energy and cost implications
of aquaculture treatment, there is an evaluation which is sadly lack-
ing at this point; one that answers the question that, if we achieve
the goals that we set, what do we accomplish?  Where are we in this
business?
     We encourage our Board to continue their good work and to do more
of it.
     As you proceed in the conference today, I would suggest that you
consider the technical papers and the experiments that are reported to
you and try to put them in a policy perspective.   See how they can
serve the greater public over a period of time.   I can tell you that
in deliberations on the State budget — that until evidence is brought
forth that this is part of a larger plan, that it is going somewhere —
there will be some reluctance to continue to sponsor individual single
projects.  At the same time,  I can say that the Governor is extra-
ordinarily responsive to implementation of alternatives when they're
in context.   Again .and again, whether it be in transportation, energy,
or other issues,  when the arguments are presented to the policymakers
so that they can see  that it  has some long-term payoff for the general
public, for the people of the State, it's sold.   It doesn't take
selling;  it sells itself.   The arguments only come when you can't
answer the question,  "Where is it  going?"
     Thank you.
                               28

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     THE FEDERAL ROLE AND INTEREST BY EPA'S
     CONSTRUCTION GRANTS PROGRAM IN AQUACULTURE
     SYSTEMS FOR MUNICIPAL WASTEWATER TREATMENT

     James N. Smith, Associate Assistant Administrator for Water
       and Waste Management, U.S. Environmental Protection Agency,
       Washington, D.C.

     Robert K. Bastian, Environmental Scientist, Office of Water
       Program Operations, U.S. Environmental Protection Agency,
       Washington, D.C.
INTRODUCTION

     Many of the Nation's consulting engineers and public health
officials have lead municipalities toward the use of capital and
energy-entensive high technologies to treat and dispose of their
increasing volumes of wastewater.  These technologies depend heavily
upon the use of equipment, chemicals, and energy in an effort to
maximize their degree of control over the treatment processes while
minimizing land requirements for the treatment facilities.  The recent
dramatic increased in cost of energy, raw materials, construction,  and
labor will eventually lead even those individuals most dedicated to
the use of high technology for the answers to man's problems to
seriously re-evaluate the potential use of more self sufficient,
managed natural ecosystems in municipal wastewater management systems.

     In response to these same pressures, a few imaginative individuals
have been striving to develop more innovative wastewater management
practices, including techniques that harness natural biological
processes to help treat municipal wastewater in a more cost-effective
and energy efficient manner while effectively recycling or reusing  the
municipal wastewater and its constituents.  While more land intensive,
such natural biological recycle/reuse systems frequently cost less  to
operate and use less energy and non-renewable resources.  They also
provide the opportunity to enhance the environment through the manage-
ment of natural biological processes that can also help improve
wildlife production and habitat availability, increase recreational
opportunities, produce biomass for use as energy sources, soil amend-
ments, animal feeds, etc.
                                      29

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 The Construction Grants Program

      Through the municipal wastewater construction grants  program of
 the U.S.  Environmental Protection Agency (EPA),  in partnership with
 states and municipalities, the funding of  municipal wastewater treat-
 ment works has grown from a relatively small  federal  grant program
 to become the largest public works endeavor in the world that is
 specifically directed to improving the environment (Ruckelshaus,
 1976).  Under the original federal assistance program, 13,764 projects
 totaling  $14 billion in eligible  costs were provided  with  $5.2 billion
 in grants for the period from 1956 to 1972.   The current program
 effort, which was launched by the Federal  Water Pollution  Control Act
 Amendments of 1972 (PL 92-500), has assisted  over  17,000 projects
 costing some $33  billion with over $24 billion in  federal  grants funded
 at the rate of  75% of  eligible costs  (EPA/OWPO, 1979).  Projects
 assisted  include  the planning,  design and  construction of  new treatment
 plants, and upgrading  of  existing treatment facilities, interceptor
 and  collector  sewers,  pump  stations,  corrections to infiltration/
 inflow and combined  sewer  overflow problems,  and sludge management
 systems.

     There has been  a  clear  trend  for  consulting engineers to rely on
 the  more  traditional and widely utilized conventional wastewater
 treatment  technologies in  the  construction of these facilities.   The
 intent of  PL 92-500 and the more  recent provisions of the Clean Water
 Act  of 1977  (PL 95-217), however, was  clearly to push toward more
 self-sufficient and permanent long term solutions based upon sound
 ecological  reuse/recycle concepts and  to encourage the technological
 community  to find better and less expensive ways to do the job (Muskie,
 1976).  In  fact, Congress has actively encouraged greater use of
wastewater management practices which  result in the construction of
 revenue producing facilities that recycle potential sewage pollutants
 through the production of agricultural, silviculture, and aquaculture
products.

The I/A Program

     The EPA has developed a program to implement the new provisions
of the Clean Water Act, which provide special new incentives for
increased use of innovative and alternative (I/A) technologies to
overcome the impediments facing increased implementation of I/A
technologies through our Construction Grants Program.   The new
provisions include increased federal funding for the design and
construction of I/A technologies  (increased from 75% to 85%),  a  15%
cost-effectiveness preference for I/A technologies over least cost
conventional technologies, 100% funding to modify or replace I/A
technology facilities should they fail, and specific set-asides  in
state allotments of construction grant funds to  fund only I/A projects.
                               30

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     When Congress passed the Clean Water Act, specific goals were
set forth for I/A technologies.  These goals, which have been incor-
porated into the Construction Grant regulations and guidance, focus
on:

     o reclamation and reuse of wastewater and wastewater constituents;
     o recovery and conservation of energy;
     o reduction in costs compared to existing conventional technologies.

Under our Construction Grants Program, EPA has defined "alternative"
technologies as proven methods which provide for reclamation and
reuse of wastewater, productive recycling of wastewater constitutents
or recovery of energy.  "Innovative" technologies have been defined
as developed methods which offer an advancement in the state-of-the-
art, but which have not been fully proven in the circumstances of
their intended use.  These innovative technologies are to be primarily
directed at achieving increased reclamation, recycling and recovery
of wastewater, beneficial use of wastewater constituents, and energy
recovery as well as cost reduction, reduction in use of resources,
and other environmental benefits.

     An area that appears very promising as an I/A technology is the
use of aquaculture systems for municipal wastewater treatment.  A
wide range of managed aquatic biological systems have been considered
and investigated for this purpose, including systems involving natural
and constructed wetlands (i.e., marshes, swamps, cypress domes, bogs,
etc.), macrophytes or other aquatic vegetation in ponds, ditches, or
raceways (e.g., water hyacinths, duck weed, algae, reeds, bullrushes,
swagrass, submerged vascular plants such as Potomogeton, etc.), and
various other systems (e.g., polyculture systems, invertebrates such
as Daphnia, finfish such as Tilapia and carp, shellfish, etc.).  Such
systems represent a logical extension of the basic land treatment
concepts which have been strongly encouraged by Congress and EPA.
While aquaculture technology has generally been oriented toward the
production of human food rather than the treatment or reuse of
wastewater, the same basic biological principles apply to essentially
all systems designed for the culture of aquatic organism whether the
systems are primarily for waste treatment or production systems
(Duffer and Moyer, 1978).

Aquaculture Alternatives, Their Potentials & Needs

     To date there have been relatively few types of projects designed
primarily to treat municipal wastewater through the use of aquaculture
processes.  While extensive use has been made of stabilization ponds
which utilize algae to help treat wastewater, only limited use has
been made of managed aquatic ecosystems involving or constructed
wetlands, water hyacinths, finfish and other aquaculture processes as
an integral part of municipal wastewater treatment systems.  The
proceedings of an earlier meeting on biological treatment of water
pollution published in 1976 by the University of Pennsylvania (Tourbier
and Pierson, 1976) provides an interesting insite into the long term
potential role of aquaculture and other biological systems for
wastewater treatment.
                                      31 .

-------
      The functional role of  wetlands in absorbing  or  removing  pollutants
 has been identified as one of  the major reasons  for preserving our
 Nation's existing wetlands (Horwitz,  1978).   Wetlands treatment projects
 do exist in Michigan,  Florida,  California  and other states which
 utilize the capability of managed wetlands to help treat municipal
 wastewater to high levels in an environmentally  acceptable, cost-
 effective, and energy  efficient manner.  The  systems  also effectively
 recycle nutrients,  organic matter and other wastewater constituents
 while improving wildlife habitat,  stabilizing stream  flows, recharging
 ground water, etc.   For the  most part,  however,  wetlands have  more
 frequently served as a handy place to dispose of many different types
 of wastes rather than  a part of carefully  designed and managed waste-
 water treatment facilities.  Such wetlands disposals  practices have in
 certain cases actually led to serious problems in  existing wetlands.
 Their potential for impacting biotic  communities in wetlands must be
 recognized.   Appropriate management practices and  adequate monitoring,
 as well as proper regulation and control of projects, must be  imple-
 mented to avoid potential ecological  problems from developing.

      The future of  wetlands  treatment systems as an I/A technology for
 municipal wastewater treatment  should be a bright  one.  However, it
 could be greatly influenced  by  public opinion as well as the concerns
 expressed by  government  officials  and scientists who  envision  wetlands
 treatment systems as the indiscriminant dumping  of raw wastes  into
 wetlands rather  than managed ecosystems for treating  and recycling
 wastewater.   Active participation by  the various groups interested in
 protecting wetlands in the development of  projects involving existing
 or artificial wetlands for municipal wastewater  treatment may  help
 improve  the acceptance of  these  projects.  We need to establish wetlands
 management practices that  can be applied to the  effective and  environ-
 mentally  acceptable use  and treatment of municipal wastewater  in
 existing wetlands as well as guidance on the  establishment and manage-
 ment  of artificial wetlands created primarily to treat wastewater if
 these systems are to ever become truly acceptable  to  the local, state,
 and federal environmental and regulatory interests.

     While considered to be weeds by  many,  water hyacinths,  duckweed
 and other aquatic plants or combination of plants and animals have
been demonstrated to be  effective in  certain  systems required  to meet
 secondary or  greater treatment requirements, nutrient removal,  and for
upgrading existing stabilization ponds.  They also show great promise
 for treating many industrial wastes.  Available land,  climatic con-
 straints, harvesting problems,  special management requirements and
other problems must be faced when utilizing many of the aquatic plants
 for wastewater  treatment.  However, their ability to effectively
utilize solar energy and wastewater nutrients to produce large volumes
of biomass allows one to consider energy and resource recovery from
 these aquatic plant systems to offer  a possible means of further
 reducing  the  cost of wastewater  treatment.   Additional potential by-
products  from such wastewater aquaculture projects include such
materials as  compost, animal feeds or feed  additives,  processed
products  such as protein extracts, bait fish and even processed food
products.
                               32

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     The increased use of natural biological processes such as aqua-
culture systems for wastewater treatment faces special public acceptance
problems and institutional constraints.   The lack of acceptance as  a
"proven" wastewater treatment technology by the sanitary engineering
profession and public officials has lead to considerable fustration
where attempts have been made to establish projects.  Their lack of
profit opportunities for system designers due to the minimal use of
equipment and engineering design requirements as well as their large
land requirements and heavy dependence upon "nature" have not been
well received by the consulting engineering community for the most
part.  How quickly the American public can accept the idea of treating
municipal wastewater by biological systems which also involve the
production of animal feeds, wetlands enhancement or even food production
could also become a major factor in public acceptance.  We hope,
however, that the incentives of the new I/A program, as well as the
potential long term savings through lower O&M costs, energy conservation
and recovery, by-product production and utilization offered by waste-
water aquaculture systems, will allow their further development and
use in the coming years.

CONCLUSIONS

     The subject of water pollution control and wastewater treatment
can be seen as a problem of biology rather than simply one of engineer-
ing.  The scientific basis for treating and the reuse/recycling of
wastewater should give greater emphasis to ecology and the management
of natural biological systems.  Neither the technological problems  of
designing biological systems nor the political and institutional
constraints facing their implementation should prevent the increased
future use of aquaculture systems for wastewater treatment.  Where
these systems can be made to work they should offer effective solutions
to the need for cost-effective, environmentally acceptable, and
energy efficient wastewater treatment and recycle/reuse practices.
In order to assist in encouraging greater use of these aquaculture
systems for wastewater treatment, we need to make sure that the
results of past and ongoing research efforts are effectively applied
to I/A technology projects funded through the EPA Construction Grants
Program.
                                       33

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                              References
Ruckelshaus, W. D.  1976.  "An Environmental Overview," IN: J. Tourbier
  and R. W. Pierson, eds., Biological Control of Water Pollution,
  University of Pennsylvania Press, pp 340.

U.S. Environmental Protection Agency, Office of Water Program Operations,
  September, 1979.  "Clean Water Fact Sheet"  p. 16.

Muskie, E. S.  1976.  "The Economy, Energy, and Clean Water Legislation."
  IN:  J. Tourbier and R. W. Pierson, eds.  Biological Control of Water
  Pollution, University of Pennsylvania Press, pp. 340.

Duffer, W. R. and J. E. Moyer  1978.  Municipal Wastewater Aquaculture.
  EPA 600/2-78-110.

Tourbier, J. and R. W. Pierson, eds.  1976.  Biological Control o_f Water
  Pollution, University of Pennsylvania Press, pp 340.

Horwitz, E. L.  1978.   "Our Nation's Wetlands" Washington, D.C.  GPO.
  (An Interagency Task Force Report Coordinated by the Council on
  Environmental Quality)
                               34

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      THE USE  OF AQUATIC PLANTS AND ANIMALS FOR THE
      TREATMENT OF WASTEWATER:  AN OVERVIEW
      George Tchobanoglous


      Rich Stowell


      Robert Ludwig


      John Colt


      Allen Knight
Department of Civil Engineering
University  of  California, Davis, CA   95616

Department of Civil Engineering
University  of  California, Davis, CA   95616

Department of Civil Engineering
University  of  California, Davis, CA   95616

Department of Civil Engineering
University  of  California, Davis, CA   95616

Department of Land, Air, and Water Resources,
University  of  California, Davis, CA   95616
ABSTRACT

      Aquatic  systems  employing plants and  animals  have been  proposed  as
alternatives  to conventional  wastewater treatment systems.  The  fundamental
difference between conventional and  aquatic  systems  is  that  in  the  former,
wastewater is treated  rapidly in highly managed environments, whereas in the
latter, treatment occurs at a comparatively slow rate in essentially unmanaged
natural environments.   The consequences of this  difference are 1)  conventional
systems require more construction and mechanization but less land  than aquatic
systems, and  2) conventional processes  are subject to greater operational control
and less  environmental  influence  than aquatic processes.   The major stimulus
for further research into the fundamentals,  design, and  management of aquatic
systems  is  the  potential  for   reducing  the  construction  and  operation  and
maintenance  costs for wastewater treatment.  The  general concepts involved in
the design and use of  aquatic  systems are presented and the implications are
discussed  in  this  overview.
WASTEWATER CHARACTERISTICS AND TREATMENT

      The  characteristics of the wastewater to be treated are of fundamental
importance in the selection and design of treatment systems whether conventional
or aquatic, employing plants and animals.  Further, the performance, reliability,
and cost of conventional  treatment  systems have become the standard  against
which other treatment systems must be compared.  For these reasons, each of
these topics is considered in the following discussion.
                                             35

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 Characteristics of Wastewater

       The  principal  contaminants of concern in  wastewater are summarized in
 Table 1.   The addition  of chlorine to treated  effluent  for  disinfection  may
 produce other  contaminants of  concern such as  trihalomethanes,  compounds
 believed to be carcinogenic.  At the concentrations found in domestic wastewater,
 the  contaminants  of greatest  immediate  concern  are biodegradable organics,
 suspended solids, and  pathogens. Problems stemming from the other  contaminants
 are  of a  more  subtle,  long-term nature and  are  neither  well understood  nor
 closely regulated at this time.  The composition of  typical domestic wastewater
 before  treatment  is  presented in Table 2.   The  impact of  the constituents
 reported  in Table  2 on  aquatic systems  is  considered  later  in this  paper.

 Wastewater Treatment:   Conventional/Advanced

       In  conventional  treatment,  the prime objective is  the  removal of  bio-
 degradable  organics,  suspended solids,  and  pathogenic bacteria (see  Table 1).
 Conventional systems are not usually designed to remove  nitrogen, phosphorus,
 pesticides, refractory organics, or heavy metals.  Typically, the basic  requirements
 of a wastewater  after receiving  secondary  treatment  and disinfection  is  that
 the  BOD (biochemical oxygen demand), suspended solids,  and coliform bacteria
 (an indicator organism for  pathogens) concentrations be less than  30  mg/L, 30
 mg/L, and 20 organisms/100 mL,  respectively.
       In many  cases, conventional secondary  treatment  of wastewater  is  not
 entirely adequate for  protection of the aquatic environment.  The concentrations
 of nitrogen and phosphorus compounds in secondary effluents are often  sufficient
 to stimulate the growth  of  algae  and other aquatic  plants.  Depending  on pH
 and  temperature, some  of the nitrogenous compounds may be lethal to  fish.
 Refractory organics and heavy metals may be toxic; they also tend to accumulate
 in plant and animal tissue.  The effects of the  many  other  contaminants  known
 to occur in trace  amounts  in the effluent  from secondary treatment systems
 are either  unknown or not  well defined.  Advanced treatment methods  can be
 used to reduce  the concentration  of  these contaminants (see Table 2), but  high
 cost  prohibits their general use.  One of  the important applications of aquatic
 systems  may be the further treatment  of  conventional secondary effluent to
 remove nutrients and trace levels  of metals, organics, and other contaminants.


 THE USE OF AQUATIC SYSTEMS FOR WASTEWATER TREATMENT

      To provide some  perspective  on  the  use of  aquatic systems and  before
 discussing their design and assessment, it is appropriate to consider  the  operative
 contaminant  removal mechanisms, some of  the plants and animals that  might
 be used, the concept  of  an  aquatic  processing unit (APU), the types of APUs
that   might be  used, and  the use  of  aquatic  systems   in integrated  waste
 management systems.

 Contaminant Removal Mechanisms

      The  principal  removal mechanisms for the contaminants of concern in
 wastewater  in aquatic systems employing plants and animals are summarized in
 Table 3. The removal mechanisms reported  in  Table  3 have been  identified on
the basis of observations of  1) natural  systems such  as marshes and wetlands,

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Table 1.—Contaminants of Concern in Wastewater  Treatment.
Contaminants
             Reason for Concern
Suspended
 solids
Biodegradable
 organics
Pathogens
Nutrients
Refractory
 organic
 compounds
Heavy  metals
Dissolved
 inorganic
 salts
Suspended  solids  can lead  to the  development
of sludge deposits and anaerobic conditions in the
receiving water.

Composed  principally of proteins,  carbohydates,
and  fats,  biodegradable organics are  measured
most  commonly  in  terms  of  BOD  (biochemical
oxygen  demand)  and   COD  (chemical  oxygen
demand).   If discharged to the environment, the
biological  stabilization of these organics can lead
to the depletion of natural oxygen resources and
to the development  of  septic  conditions.

Bacteria   and   viruses   capable   of   causing
communicable disease can be transmitted by water
routes.

The nutrients essential for growth include  carbon,
nitrogen, phosphorus, and  trace elements.  When
discharged   to  the   aquatic  environment, these
nutrients   can   lead  to  excessive  growths  of
undesirable aquatic life.

These  organic  compounds  tend  to  be toxic  in
relatively  low concentrations.   Some  may  also
accumulate in  the environment,  biologically and
on adsorptive  surfaces, concurrent with the slow
decay  of  these compounds.   Typical  refractory
organics are surfactants, phenols,  and agricultural
pesticides.

Heavy metals  are often toxic in relatively low
concentrations.       These   contaminants   are
elemental,   i.e.,   environmentally  conservative.
They  tend to  accumulate  biologically  and  on
adsorptive   surfaces.     Typical   examples  are
mercury, lead, and cadmium.

Inorganic  constituents  such as calcium,  sodium,
boron, and sulfate  may  have to be  removed  if
the wastewater is to be reused.
 Adapted from Metcalf  and Eddy, 1979.
                                           37

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Table  2.—Typical Composition of Domestic Wastewater Before and  After Treatment
          (All Values Except  Settleable Solids and Coliform  Bacteria are Expressed in
          mg/L).
Concentration
Constituent
Solids, total
Dissolved, total
Fixed
Volatile
Suspended, total
Fixed
Volatile
Settleable solids, mL/L
Biochemical oxygen demand, 5-day
20 C (BOD, 20 C)
Total organic carbon (TOC)
Chemical oxygen demand (COD)
Nitrogen (total as N)
Organic
Free ammonia
Nitrites
Nitrates
Phosphorus (total as P)
Organic
Inorganic.
Chlorides
Coliform bacteria, MPN/100 mL
Heavy metals
Refractory organics
Alkalinity (as CaCOj
Grease
Before
Treatment
Range
350-1200
250-850
145-525
105-325
100-350
20-75
80-275
5-20
110-400

80-290
250-1000
20-85
8-35
12-50
0-0
0-0
4-15
1-5
3-10
30-100
105-109
0.1-2.5
0.2-7.4
50-200
50-150
Typical
720
500
300
200
220
55
165
10
220

160
500
40
15
25
0
0
8
3
5
50
107
1.3
1.4
100
100
After After
Secondary Advanced
Treatment Treatment




20 <3



20 1


80 10
30 2




2



20 <2
.8 <0.1
.2 <0.1


 From  Metcalf  and Eddy, 1979.

^Should be increased by  the  amount  in domestic water  supply.

'Surfactants, primarily.
                                  38

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          Table  3.—Contaminant  Removal Mechanisms  in Aquatic Systems Employing Plants and Animals
                                                                Contaminant Affected
                 Mechanism
Description
Physical
Sedimentation
Filtration
Adsorption
Chemical
Precipitation
Adsorption
Decomposition
Biological
Bacterial Metabolism0
Plant Metabolism0
Plant Absorption
Natural Die-Off

P
S










S
S
S




P




I






P




I






P

S


I


P
P




S


I


P
P




S


I



S
P

P
S
S


I




P


S

P

Gravitational settling of solids (and constituent contaminants)
in pond/marsh settings.
Particulates filtered mechanically as water passes through
substrate, root masses, or fish.
Interparticle attractive force (van der Waals force).
Formation of or co-precipitation with insoluble compounds.
Adsorption on substrate and plant surfaces.
Decomposition or alteration of less stable compounds by
phenomena such as UV irradiation, oxidation, and reduction.

Removal of colloidal solids and soluble organics by suspended,
benthic, and plant-supported bacteria. Bacterial nitrification/
denitrification.
Uptake and metabolism of organics by plants. Root excretions
may be toxic to organisms of enteric origin.
Under proper conditions significant quantities of these
contaminants will be taken up by plants.
Natural decay of organisms in an unfavorable environment.
CO
CO
           Adopted from Stowell et al., 1979

           "^primary effect, S=secondary effect, ^incidental effect  (effect occurring  incidental to  removal of another contaminant).

           "The term metabolism  includes both biosynthesis  and catabolic reactions.

-------
 and 2) laboratory and pilot  scale studies of aquatic systems employing  one or
 more  plant  and/or animal species.   An understanding of these mechanisms is
 important because the selection of plants and animals for  use in aquatic systems
 will depend  on the  contaminants to be  removed  and the removal  mechanisms
 that  must be used for their removal.   For  additional information  on removal
 mechanisms  in aquatic systems see  Stowell  et  al. (1980).
       In aquatic  systems, the plants  and animals themselves  bring about  very
 little actual treatment.  The major  treatment in  these  systems is accomplished
 by  bacterial  metabolism.   In effect water  hyacinth or  wetland systems are similar
 to  a  large, slow-rate trickling filter with built-in secondary  clarification.

 Potential Plant and Animal Use  in  Aquatic  Systems

       Potential aquatic  plants  and  animals and  their probable role in aquatic
 systems are  presented in Table 4.  When selecting organisms for use in an APU
 the  designer must  consider  not only   an  organism's  effect   on  the aquatic
 environment  but  also its  compatibility with the climate and environment  of  the
 design  site.   Organisms  incompatible  with climatic and  environmental  factors
 will  tend to have  unstable  populations  resulting  in  fluctuations  in aquatic
 environmental quality and, ultimately, in APU performance, (i.e., unreliability).
 Plants are expected to play a more dominant role than animals in aquatic systems
 because of  their   greater  influence on   the  aquatic environment  and greater
 adaptiveness to harsh and/or  fluctuating environmental conditions.   Plants have
 significant impact on the aquatic  environment  by 1) providing a medium  for
 filtration/absorption of solids and growth of  bacteria  and 2) affecting gas and
 radiation transfer  between the aquatic environment and atmosphere.
       As reported  in  Table 4,  there are three general categories of plants:
 floating,  emergent, and submerged.   Floating plants  have their photosynthetic
 parts  at or just above the  water surface  with roots extending below the surface.
 With  floating plants, the penetration of  sunlight into the  water is reduced and
 the transfer of gas between water and atmosphere is limited.  As a consequence,
 floating plants in ponds tend to keep the wastewater free of algae and essentially
 anaerobic.  Emergent plants  are rooted  in the  substrate  and have their photo-
synthetic parts extending above  the water surface.   These plants  also reduce
light penetration and gas transfer, but to a lesser extent as compared to floating
plants.   Water in  stands  of  emerged  vegetation is  usually free  of algae  and
partially aerobic.   Submerged plants, including  algae, may be  suspended  in the
 water column or may be rooted to the  substrate.  During the  sunlight hours this
category  of plants oxygenates the water.
      The primary role of aquatic animals may be to further clean-up or "polish"
wastewater treated by removing suspended solids before  discharge.   Dissolved
oxygen and ammonia levels will be critical in APU's using  aquatic animals.  The
control  of insect  vectors,  the  accumulation  of heavy  metal  and refractory
organics,  and their function as  bioassay test  organisms are important secondary
roles  served  by animals.

Aquatic  Processing Units:  A  Conceptual Model

      An aquatic  processing unit (APU) is defined as the assemblage of aquatic
plants and animals (see Table 4) grouped together to achieve a specific treatment
objective (e.g., removal of nutrients and heavy metals).  In this context, an APU
 is a definable physical entity that represents some  discrete  step in the treatment
of a wastewater.   For example, one or  more APU's could be used in  conjunction
                                 40

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Table *.—Potential Aquatic  Plants  and Animals  for  Use in Aquatic Systems  for
          the  Treatment  of  Wastewater.
               Organism
       Probable role  and remarks
Floating aquatic  plants

  Water hyacinth (Eichhornia spp.)  Its   extensive  root  system   serves   as  a
                                   mechanical filter  and  a  support  structure
                                   for  bacteria.   Mats of hyacinth  attenuate
                                   sufficient  light  to  prevent the  growth of
                                   algae.  Wastewater leaving hyacinth mats is
                                   devoid of oxygen, typically.  Hyacinths will
                                   not   winter-over   in   colder   temperate
                                   climates.   Water  hyacinths  are  potential
                                   aquatic pests.

  Water primrose (Ludwigia spp.)   This  temperate climate plant is similar to
                                   the  water  hyacinth, ecologically.  The root
                                   system  is  not  as extensive as that of the
                                   hyacinth nor is the  floating vegetative mat
                                   as   dense.     Water   primrose   attenuate
                                   sufficient  light to prevent algae  problems.
                                   Wastewater  leaving  primrose  mats   may
                                   contain dissolved oxygen.   This  plant is a
                                   potential  nuisance.
  Duckweed  (Lemna  spp.)
Emergent aquatic plants

  Cattails  (Typha spp.)
The  root  system of this small plant is not
of  engineering  significance.    Duckweed
grows in dense mats that effectively  restrict
gas transfer and attenuate light.  Ubiquitous
in  the United  States,  duckweed  is  not
considered a major aquatic pest.   Wind can
disrupt duckweed  mats.    Duckweed  can
survive throughout  the winter  in  milder
temperate climates.
The  submerged portion of  a cattail  stand
serves as a mechanical filter and a  support
structure for bacteria.  Algae will not grow
in  dense  cattail   stands,  however,  water
leaving stands is aerobic,  typically.  Cattails
successfully   winter-over   even  in   harsh
climates.
                                                                continued
                                          41

-------
 Table 
-------
Table 4 (continued)
       Organism
     Probable  role and remarks
  Aquatic  animals

  Zooplankton
  Fish
    Blackfish
    Carp
    Tilapia
    Catfish
    White amur
    Mosquito fish
  Bivalves/clams
  Crustacea
    Crayfish
    Prawn
    Shrimp
These organisms accumulate algae and  other
suspended  particulates into a  larger  sized
participate.  Their presence and effect  are
sporadic.   The management of zooplankton
populations has proven to be difficult.
Fish serve in a role similar to that described
for zooplankton.  Zooplankton  retain fewer
particles than  do most fish.   Fish  can also
be  used  to  reduce the  vegetative  standing
crop, control mosquitoes, or  convert  plant
protein to animal protein.  Fish populations
are manageable.

Clams filter-feed on particulates.   To be
most  effective,  clams should be suspended
in the water column  rather than be  placed
on  the substrate.
These  omnivores would be useful primarily
as test and  bioassay  organisms.   They  are
sensitive to  pollutants.
                                          43

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 with conventional treatment methods to achieve a desired degree of wastewater
 treatment or several APUs  could be used  together to form  an entirely aquatic
 treatment system.  The conceptual use of APUs to accomplish various wastewater
 treatment objectives is illustrated in Figure 1.
       The APUs in Figure 1 are  arranged  so  that the application is  from least
 to most complex.  For example, in Figure la, the APUs are used for the removal
 of nutrients, refractory organics, and heavy metals.  In contrast to  this relatively
 simple  application,  the complete treatement  of  wastewater  with  an APU is
 envisioned in Figure Id.  Still more complex is the flowsheet in which an APU
 is used  for  the complete  treatment of wastewater  (Figure  If),  including  the
 removal and disposal of solids handled  by the primary treatment facilities used
 in flowsheets la through Id.
       At present, what little is known about  the use of plants  and  animals  for
 the  treatment of wastewater is  related primarily  to the  removal of nutrients
 (nitrogen  and phosphorus), refractory organics,  and  heavy metals from effluents
 of  conventional treatment systems (Figure la).  While this  information  is  of
 value, research is  needed to  define the  conditions under  which various  types  and
 combinations  of aquatic species may be  used in  various  types  of  APUs  to
 accomplish primary,  secondary,  and advanced levels of wastewater treatment
 (Figure Ic through If).  Because nitrogen  and phosphorus removal is not normally
 required by  regulatory agencies,  the  greatest  potential  for  aquatic  systems is
 for secondary treatment.

 Types of  Aquatic  Processing Units

      In practice, APUs will contain different  types and combinations of aquatic
 species, be managed  or operated in  different  ways, and have physical features
 that differ  with the function of the APU  in the treatment  system  (see Figure
 1).   The  most  common  types  of APUs that  have  been tried  for  wastewater
 treatment  include natural and  man-made  marshes, wetlands, and various pond
 systems in  which  one  or  more plants  are used.  Some more complex aquatic
 systems have been developed in Europe, but  their use  is not  well documented
 in the literature.  Further, a number of these systems are  patented.  While  the
 use of a low-energy unmanaged  system  such as a marsh is desirable, some level
 of control may be  required because of environmental  conditions or to  meet
 treatment objectives.  As an example, a desirable aquatic plant species may  not
 reproduce in certain climates.  In such  cases,  nursery  and planting  operations
 might become  a part  of  the treatment system.   In  another  case, a particular
 harvesting  procedure may  be necessary  to  accomplish the  treatment objectives
assigned  to the APU.   In  still other cases, the APU  environment may have  to
be controlled using physical  features  such as a greenhouse, aeration systems  or
artificial substrates.   The tremendous  variation possible in APUs  is a  point  of
confusion, at present, but,  as the performance of selected APUs is defined, this
flexibility in the selection of APU  type should become an asset  in the design
of aquatic treatment systems for different locations.

Integrated Waste Management Systems

      The opportunity  to  incorporate  conventional treatment  systems into  an
integrated  waste management system  capable of  some  resource  recovery has
 always existed but up  till the present time (1979)  has not  been done routinely.
 In conventional treatment systems the principal objective is to reduce the energy
                                44

-------
WASTEWATER
          COARSE SCREENING
    (e)| \AND COMMINUTION ONLY
E REUSE
DISCHARGE
AQUACULTURE
                         FIGURE  1

      APPLICATIONS OF AQUATIC PROCESSING UNITS
          FOR THE TREATMENT OF WASTEWATER
                                     45

-------
 contained in the wastewater (principally in organic compounds as measured with
 the BOD test) by respiration and to "harvest" as little biomass as possible, which
 is somewhat at odds with the concept of resource recovery.
       By the nature of the contaminant removal mechanisms involved in aquatic
 systems, there is an opportunity  to  incorporate these systems  into an integrated
 waste management system.  Although aquatic systems lose energy to respiration,
 they  gain energy with the growth of photosynthetic plants. An important feature
 of aquatic systems is their ability to concentrate energy and nutrients in a more
 readily usable form, as compared to conventional treatment  systems.  Harvested
 materials from  aquatic  systems  may  contain  up to  20 percent solids,  whereas
 the biological  mass removed from  conventional systems seldom contains more
 than  one  percent solids.
       An example of  an integrated waste management and recovery system  is
 presented in Figure 2.   The option of producing a combination  of energy or
 animal feed is available.  As shown, plant  tissue from the aquatic systems could
 be used, singly or in combination with other solid wastes, as feed for fermentation
 or pyrolysis processes  that can be used to produce usable energy and to  reduce
 the volume  of solid  wastes and sludge.  The selection of an operating  strategy
 for an integrated system will depend on local conditions.  It must be emphasized,
 though, that the primary purpose of  the aquatic system  is  the  treatment of
 wastewater  and not the production  of energy, feed,  or other  products.


 DESIGN CONSIDERATIONS FOR AQUATIC TREATMENT SYSTEMS

 Design considerations  for aquatic treatment  systems  are  more complex than
 those  for  conventional systems  because  more  variables  are involved, many of
 which are  beyond the direct control of  man.   Aquatic  species must  be found
 that are capable of  removing contaminants while surviving climatic and waste-
 water conditions.   The  design  and managerial  practices  for  APUs  must  be
 formulated  to  provide  the environment  necessary  for the aquatic species to
 function as intended. Aquatic systems may have performance reliability problems
that will require special designs.  The recovery of resources  will also affect the
design of  these  systems.

Selection of Species

       The  selection of aquatic  plants  and animals to be used  for  wastewater
 treatment will be  based, to a  large extent, on  their  ability  to  provide  and
maintain an environment in which  wastewater treatment will occur.   Because
the functional performance of whatever aquatic species are  used will depend on
their  growth  and reproduction,  the impact of factors  affecting  growth  and
 reproduction such as wastewater  characteristics, local environmental conditions,
and APU  managerial practices  must be  known.  A  number of  related  factors
must  also be considered.

       Impact  of Wastewater Characteristics.   Wastewater characteristics  of
concern with  respect  to  the aquatic  plants  and animals that may be used in
treatment  systems are listed  in Table 5.   In  general,  aquatic animals (fish,
crustaceans, bivalves) are more sensitive than plants to most wastewater contam-
inants so  that  some  pretreatment of the  wastewater  may be necessary using
either conventional methods or aquatic  plants.  When toxic or  bioaccumulable
chemicals are  known  to  be  present in significant quantities a more  specific
                                46

-------
Metal, Glass
              FERMENTATION,
              GASIFICATION
                              ANIMAL
                              TISSUE
                             PRODUCTION.
                                                                     i—•• Disposal
                                                                       Other
                                                                      ' Reuse
FUTURE
POTENTIAL
TECHNOLOGIES
    CONVENTIONAL TECHNOLOGY

    ALTERNATIVE TECHNOLOGY
                             FIGURE 2

        AN INTEGRATED WASTE  MANAGEMENT SYSTEM
           EMPLOYING AQUATIC PROCESSING UNITS

-------
 Table 5.—Wastewater Characteristics of Concern  with  Respect to the Use of
          Aquatic Plants and Animals for Treatment of Wastewater.a


                                         Relative Importance To
    Characteristic                        Plants                      Animals
                                                                      +++
Temperature                             +++

Suspended  solids                   0 Emergent  species
                                +++ Submerged species

Dissolved oxygen                  0 Emergent  Species
                                 +++Submerged species

N_ supersaturation                        0                            +

Total nitrogen                            +++                          ++f

Phosphorus                               ++                            0

Heavy  metals                            ++                          -1-+
                                           2
Boron                                    ++                            0

Salinity                                  ++                           ++

Refractory organics                       +                           ++
aAny  of these parameters  could  be  limiting over a sufficiently wide range.
 The relative  importance ascribed to these parameters here is  related to the
 variation expected in domestic wastewaters.

 0    No direct influence
 +    Influential
 ++   Important
 +++  Critical
 1    Growth nutrient
 2    Toxicity (depends  on form  of chemical compound)
                                48

-------
characterization of the wastewater may be necessary so that corrective measures
can be taken.  The  presence  of  industrial wastes may  pose  particular problems
for aquatic systems.  Injury or death  of  a plant  or animal  species may reduce
the treatment performance of an aquatic system for weeks or months, depending
on the recovery or  regrowth  time of the  organism(s)  affected.

      Impact of Local Environmental Conditions.   Local environmental conditions
that must  be considered include: climatic conditions, substrate characteristics,
and local flora and  fauna.  Based on a preliminary assessment, it appears  that
the climate at  the wastewater treatment  site may be the major determinant  of
the type of aquatic  species to be used.  Important climatic factors are seasonal
averages  and diel variations  in  the  air  temperature,  the  average  number  of
overcast days,  local photoperiod, light intensity, the  duration and intensity  of
rainfall,  the strength and frequency of  winds, and the  probability  of  unseasonal
weather.  For some plant  and animal species a good deal of information exists
about their  climatic tolerances, for other species this information is non-existent.
Detailed  information  on  the  environmental  requirements  of aquatic  plants
(Stephenson et al., 1980), fish  (Colt et al.,  1979), crustaceans (Colt et al., 1980b),
and freshwater  bivalves (Colt  et al., 1980a) is available.  The presence  or absence
of suitable  substrate  will  be an  important factor in   the  design  and operation
of aquatic  systems.   Local flora and  fauna similar to  those  to be used  in the
system  should  be investigated  for  predation so   that  the possibility  of system
upsets from indigenous predators can be  controlled.

      Impact of APU Managerial Practices.  Managerial practices  for APUs will
affect  and  be  affected  by  the  species selected.   The  match between the
environment, as determined by wastewater characteristics and  climate, and the
environmental  requirements of  the  selected species  needed  to  optimize their
function in  the treatment  process will  rarely be  perfect.   Managerial practices
are an  additional aspect  of  the APU  concept that,  if applied,  can create  an
environment closer  to  the  optimum  for  the  selected  species.   Typical  APU
managerial  practices  may include  pretreatment  of  the wastewater, biomass
harvesting,  aeration, controlled recirculation, control of  residence times, and the
use of artificial substrate and organism support  materials.

      Impact  of  Other Factors.   Many  factors  in  addition to  wastewater
treatment  potential, environmental suitability, and species  manageability must
be  considered  when  selecting organisms for  use in  aquatic  systems.   These
additional  factors  include  the  quantity and quality of solids  produced by the
organisms  and  their subsequent  disposal;  restrictions on  the use of organisms
considered aquatic pests; site  constraints such as odor production, fog generation,
or vector insect problems; and other site-specific  factors.  Only under prototype
or full-scale operation  will it be possible to evaluate some of these factors.

Design  of Aquatic Processing Units

      The  rational  design of APUs  is not yet  possible because  most of the
critical  design parameters are  either  unknown  or poorly  defined.   Additional
information on the design  of  aquatic treatment systems can be found in Stowell
et al. (1980) and Ludwig et  al. (1980).   Species-specific  information must  be
developed about the contaminant removal  potential of aquatic plants and animals
as a function of the system constraints.  Once the treatment potential of  each
species  under consideration is known,  the  design  of APUs and  aquatic treatment
                                         49

-------
 systems can be undertaken.   If  combinations  of species are  to be  used  within
 a single APU, then the interaction  between these species  must be  determined.
 When  more than one APU is used, the designer must  not overlook the possibility
 that the effluent from one APU may not be compatible with the organisms of
 the  next APU.  Species-specific and system-specific laboratory and pilot scale
 studies will have to be verified by prototype projects to demonstrate  how well
 aquatic  species  and  systems perform  under  the varied  and often  unpredictable
 conditions that may  be encountered in the treatment of wastewater.

 System Reliability

       An  important design consideration is system  reliability (freedom from
 failures in treatment).  Aquatic system reliability problems stem from  climatic
 conditions,  wastewater characteristics, environmental factors,  and  disease that
 disturb, injure, or kill the plants  and animals used for treating the  wastewater.
 The potential for and consequences of poor system reliability is  greater in aquatic
 systems than in conventional systems because of greater  environmental exposure.
 Also,  a  managed community  of higher  aquatic  plants  and  animals lacks the
 diversity  and  rapid growth rate  of  indigenous bacterial populations.   Whereas
 process upsets  in conventional  systems last for  a matter  of  hours or  days,  upsets
 in aquatic systems may last from days to months, depending on the extent of
 the damage and the  recovery  time of the organisms affected.  In  cases  where
 there is a possibility of relatively long down-times due to climate or the  nature
 of the wastewater, an  alternate treatment system may  have to be  part  of the
 aquatic system  design.  Ways must  be developed  to control and minimize the
 effects of aquatic  system process upsets.

 Resource Recovery

       Because there will  be biomass  production, the recovery of resources from
 aquatic systems  offers a possible means of  reducing  the  cost of  wastewater
 treatment.  Harvested biomass could  be used  in the production  of livestock feed,
 compost,  soil  ammendments, or energy.   The economics of resource  recovery
 will depend on the availability of local  markets  and uses for  the products.  Local
 consumption of these would reduce the need for expensive processing and transport
 equipment.  When the economics of a resource  recovery operation are favorable,
 criteria related  to resource recovery  should be considered in  the  selection  of
 species and in  the  design  systems.    Resource  recovery should be considered
 carefully  if its inclusion might  diminish  the performance  or  reliability of the
aquatic treatment system.


ASSESSMENT  OF AQUATIC SYSTEMS

       The  success  and acceptance of  aquatic  systems  will depend largely  on
how well  they  compare with conventional systems.  The bases for  comparison
will include treatment  efficiency, health  risks, and  costs.   Federal legislation
and administrative  policies  will  also be  an important factor in the  application
of such systems.

Treatment Efficiency, An Overview

       Performance  and  reliability  are  important  factors  in assessing the
applicability  of  aquatic systems for  wastewater  treatment.   At   present,
                                50

-------
insufficient  data exist to  allow a comparison between aquatic systems employing
plants  and  animals  and conventional systems.   From  an analysis  of  published
data on  water hyacinth  and  wetland systems  (Stowell et al.,  1980; Ludwig et
al., 1980) it has been  found that these systems remove 80 to 83 percent of the
BOD and SS  (suspended  solids).   The  BOD  removal  characteristics  of  water
hyacinth systems  are  presented  in  Figure 3.   The upper value of  BOD loading
was 2^5 kg/ha»d, approximately 5 times the normal loading rate for  conventional
wastewater  stabilization ponds.  The performance capabilities of aquatic systems
appear favorable, especially for the removal of nutrients and trace concentrations
of toxic substances.  Reliability may be a major shortcoming of aquatic systems.
Short-term  reliability  may  not  be as  important  as the  total  quantity of
contaminants  removed  when  considering contaminants  with  chronic rather than
acute effects  (e.g.,  nutrients, refractory  organics, and heavy  metals).
      Considering both performance and reliability, at least one use of aquatic
systems will be the  further treatment  of  secondary effluents from  conventional
systems  where  higher  levels of  treatment are  required.   Other  uses may be
discovered as aquatic species growth, materials uptake, and pathology are defined
with respect  to  the design and  operation of aquatic systems.  In the  initial
development of aquatic  systems, it will  be important to avoid  prejudging the
usefulness of  these  systems on an all-or-nothing basis.

Health Risks

      Health   risks  for  aquatic systems  are  probably  not higher  than for
conventional treatment.  This is assuming  that the animal and plant  tissue grown
is not  used for  human  consumption  and  that  potential vector problems are
controlled.  The public health hazards of direct consumption  of organisms grown
in domestic wastewater  are  very serious and complicated.    State  and  federal
laws do  not allow direct consumption of  these products (Kildow and  Huguenin,
1974).   Their  use for  animal feeds may  be possible  if the  residues  of heavy
metals, trace  organics, and pesticides meet state  and  federal regulations.

Costs

      Based on a  preliminary analysis, it has been shown  that  aquatic  treatment
systems  have  lower capital and O&M (operational and maintenance)  costs and
use less energy (Tchobanoglous  et  al., 1979).   A cost and energy comparison
between conventional  activated sludge and artificial  wetland treatment systems
is presented in Table 6  for  plant  sizes  of 0.1,  0.5, and 1.0 Mgal/d.  Proper
assessment of the costs of  these  systems  will need to be based on  prototype or
demonstration  units.  In  this regard, it will be important to consider  the total
cost.   This  will include the  capital and operating costs  and the salvage  value.
Most of the capital  costs of  aquatic systems  will be in land which  should have
a high salvage worth.
      With  lesser mechanization,  lower energy  and  resource consumption, and
the possibility of  some  resource  recovery, operating costs  should  be  lower for
aquatic systems as compared to conventional systems.   Further, the useful life
of aquatic systems  should be longer than for conventional systems.   For these
reasons,  it  may be  feasible to build aquatic systems with capital  costs  similar
to or even higher  than the costs of  conventional  systems.  The societal benefits
of using labor intensive  aquatic systems  that may not be  cost-effective  when
evaluated by current methods should  also be considered in assessing the  operating
                                         51

-------
     250
     200
•o

5
£   150
Q
LU
>
o
2.
OJ
     100
     50-
      0
DATA FROM  15 DIFFERENT  STUDIES


         • Primary


         o Secondary
                  50
           100         150         200


         ROD   LOADING (kg/ha-d)
250
                               FIGURE 3


              EFFECT OF BOD LOADING ON  BOD REMOVAL

                        (from Ludwig et al., 1980)
                             52

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                                                       Table 6

                                 COSTS AND ENERGY UTILIZATION FOR ACTIVATED
                              SLUDGE AND ARTIFICIAL WETLAND TREATMENT SYSTEMS
01
CO
PLANT SIZE, mgd
0.1
ITEM
Capital
O & M
Energy,
cost,
cost,
$xlO
$/yr
Btu/yr xlO
CONV.
-6
xlO"3
-9
0
.71
35
0
.88
AQUA
0.37
21
0.51
0.5
CONV. AQUA
1.23 0.55
78 48
3.15 1.20
1
CONV.
1.60
117
4.80
.0
AQUA
0.90
74
2.08
                     Adapted from Tchobanoglous, et al.,  (1979).

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 costs.   It  is  anticipated that consideration  of employment opportunities  will
 become more  important  in the future.
       Depending  on  the  site, aquatic systems may have additional costs and/or
 benefits. Additional costs may include the control of vectors, such as mosquitoes
 or  other  problems relating to the presence of marshlike environments,  e.g. fog
 generation.   Beneficially, aquatic systems may  serve  as recreation  areas or
 greenbelts.

 Federal Legislation and Administrative Policy

       The  passage of the Clean Water Act  of  1977  (PL  95-217)  encourages
 the use of innovative and alternative technologies for water reuse.  Conventional
 treatment facilities  will  not be  funded unless  alternative treatment processes
 have  been studied and evaluated.  Financial bonuses are offered when alternative
 processes  are  designed; but many consulting  engineers  are reluctant to submit
 treatment-plant designs based on technology that is not nearly as well documented
 as  the  conventional  treatment  systems.  Up  to 75  percent of the construction
 costs of  new treatment  systems  is  provided  for in  PL 92-500,  but  operational
 funds are not  provided.   As a result,  several advanced wastewater  treatment
 facilities have had to  shut down  because of  excessive operating costs.  In the
 future,  rising costs for  energy and  resources will probably cause the shutdown
 of additional plants and change the design and operation of others.  If they can
 be  shown to be feasible,  aquatic systems may offer  an alternative.   Ultimately
 it may  be necessary  to revise the existing discharge requirements to make the
 use of aquatic systems a  reality.
ACKNOWLEDGEMENTS

       This  work was  supported  with funds made  available from  the  California
State  Water Resources  Control  Board to the Department of Civil Engineering
and the Department of Land, Air, and Water Resources, University of California,
Davis, California.


LITERATURE CITED

Colt,  J. et al.  1980a.  The use and Potential of Aquatic Species for Wastewater
Treatment.    Appendix  D.   The  Environmental  Requirements  of Freshwater
Bivalves.  Publication  No.  65,  California State Water  Resources  Control  Board,
Sacramento,  California.

Colt,  J. et al.  1980b.  The Use and Potential of Aquatic Species for Wastewater
Treatment.   Appendix C.   The Environmental Requirements of  Crustaceans.
Publication No. 65,  California State Water Resources Control Board, Sacramento,
California.

Colt,  3.,  S.  Mitchell, G.  Tchobanoglous, and A.  Knight,  1979.   The  Use and
Potential  of Aquatic  Species  for  Wastewater Treatment.   Appendix  B.   The
Environmental Requirements of Fish.  Publication No. 65, California State Water
Resources Control  Board,  Sacramento, California.
                                54

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Duffer, W.  R. and 3. E. Mayer.  1978.  Municipal Wastewater Aquaculture.  U.S.
Environmental  Protection  Agency, EPA-600/2-78-110,  Ada, Oklahoma, 46  pp.

Golueke,  C. G.  1979.  Aquaculture in Resource Recovery.  Compost Science/Land
Utilization, 20(3):16-23.

Kildow,  3.  and  3.  E.  Huguenin,  1974.   Problems and  Potential of Recycling
Wastes for  Aquaculture.   Massachusetts  Institute of  Technology,  Cambridge,
Massachussets,  MITSG  74-27,  170  pp.

Ludwig, R.  et al. 1980.  The Use and Potential of Aquatic Species for Wastewater
Treatment. Appendix E.  The Use of Aquatic Systems for Wastewater Treatment:
An  Assessment.  Publication No. 65,  California State  Water Resources Control
Board, Sacramento, California.

McKim,  H. L.   1978.   State  of Knowledge in Land Treatment of Wastewater.
Volume  2,  U.S. Army Corps  of Engineers,  Hanover,  New Hampshire,  423  pp.

Metcalf  and Eddy, Inc.  1979.  Wastewater Engineering:   Treatment,  Disposal,
Reuse.  McGraw-Hill,  New York,  920  pp.

National  Research  Council.    1976.    Making  Aquatic Weeds Useful:   Some
Perspectives for Developing Countries.  Washington, D.C.,  174 pp.

Sculthorpe, C. D. 1967. The Biology of Aquatic  Vascular Plants.  Edward Arnold
Ltd. London,  580 pp.

Standard  Methods.    14th ed.,  1976.   American  Public  Health Association,
Washington, D.C.,  1193 pp.

Stephenson, M., G. Turner, P. Pope,  A. Knight, and G.  Tchobanoglous.  1980.
The Use and Potential  of Aquatic  Species for Wastewater Treatment.   Appendix
A.  The  Environmental Requirements  of Aquatic Plants.   Publication   No. 65,
California State Water Resources Control  Board, Sacramento,  California.

Stowell, R., R. Ludwig, 3.  Colt, G. Tchobanoglous.  1980.   Toward the Rational
Design of Aquatic  Treatment Systems.  Presented at the American Society of
Civil  Engineers  Spring Convention, Portland, Oregon,  April 14-18, 1980, 43 pp.

Tchobanoglous,   G.,  3.  Colt,  and  R.   Crites.    1979.    Energy  and   Resource
Consumption in Land and Aquatic Treatment Systems.   Presented  at the Energy
Optimization  of Water and  Wastewater  Management for Municipal and Industrial
Applications  Conference,  Department  of  Energy,  New  Orleans,  Louisiana,
December  10-13, 1979, 12  pp.

Tourbier, 3. and R. W. Pierson, 3r. (Eds.).   1976.  Biological Control  of Water
Pollution, University of Pennsylvania  Press, Philadelphia, 340 pp.
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Wetland Processes
Session

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      Color infrared aerial photo of the Houghton Lake, Michigan wetland
 wastewater treatment facility at the Porter Ranch peatlands. Areas of reddish
 brown color near the irrigation pipeline depict areas of highest productivity.
 Partially treated wastewater is pumped through a 12" diameter underground
 force main to the edge of the wetland. At the lower left hand side of the
 photo the transfer line surfaces and runs along a raised wooden platform for
 a distance of about 2,500' to the discharge area in the center of the wetland
 Inserts depict the wastewater being distributed into the wetland through
3,200' of gated irrigation pipe.

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                WETLAND PROCESSES:  SESSION SUMMARY
Presentations in this Session cover wastewater treatment utilizing
natural and artificial wetlands.   Several regions of the United States
are represented with projects being located in California, Florida,
Massachusetts, Michigan, and Wisconsin.

Results of these studies indicate that discharge of secondary wastewater
into natural  wetlands can be an effective treatment mechanism.  One
full-scale municipal system has been established.  The wetlands process
was the alternative selected for expansion of a sewage treatment plant
in northern Michigan.  The concept and design were approved by regulatory
agencies, and the construction phase of the 201 Facilities Planning process
was completed during 1978.  This natural  wetlands system has been very
successful in the removal of nutrients from secondary sewage effluent.

Creation of an artificial marsh has demonstrated substantial environ-
mental benefits.  A 21-acre marsh was created in the San Francisco Bay
area of California.  The primary purpose of establishing the system was
to provide additional wildlife habitat.  An average of 1,600,000 gallons
of secondary sewage is discharged daily into the artificial marsh.  The
system has been very successful with 86 species of birds, 63 plant species,
34 species of aquatic invertebrates, and 22 species of other animals
having been identified.  Improved water quality was an additional benefit
noted.

These exploratory or "proof of concept" studies constitute an extremely
valuable contribution to the technology base required for advanced or
developmental studies in the wetlands area of wastewater aquaculture.
At this time, the technology base appears adequate to warrant considera-
tion of design and evaluation of pilot-scale wetlands facilities for the
purposes of stripping nutrients from secondarily treated wastewater and
creating additional wildlife habitat.
                              Prepared by
                              William R. Duffer
                              1/3/80
                                       59

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WETLANDS CREATION FOR HABITAT AND TREATMENT - AT MT.  VIEW SANITARY DISTRICT,  CA.
Francesca C. Demgen , Aquatic Biologist, Mt. View Sanitary District,
    Martinez, California


In 1974 the Mt.  View Sanitary District (MVSD),  near Martinez, California
initiated a full scale pilot wetlands creation program on low lying reclaimed
tide lands owned by the District.  The objective of the program was to
demonstrate the feasibility of utilizing plant effluent to create a wetlands
environment for the benefit of wildlife and migratory waterfowl and to develop
management techniques for improvement of both water quality and wildlife
habitat.

The concept of using treated sewage effluent as a freshwater source for the
creation and restoration of wetland ecosystems qualifies as an alternative
wastewater management technology for meeting the objectives of the 1977 Clean
Water Act Amendments promoting the use of land treatment processes that reclaim
and reuse municipal wastewater.  Wetlands reclamation projects are cost-
effective and depending on site conditions, energy requirements are minimal.
Wetlands projects also are consistent with EPA1s multiple use policy supporting
wastewater management practices which combine open space, recreational and
educational considerations with such management.

PHYSICAL FACILITIES DESCRIPTION

Treatment Plant

Mt. View Sanitary District was established in 1923.  It serves a portion of
the City of Martinez and unincorporated areas of Contra Costa County, with a
present population of approximately 14,000.  The process provides two-stage
biofiltration with separate sludge digestion.  Facilities include comminution,
primary and secondary clarifiers, a rock biofilter with a rotating dual
distributor, recirculation pumps and chlorination facilities.  Sludge handling
facilities include grit removal, sludge thickening and primary and secondary
sludge digestion.  A belt-filter press and paved drying beds provide for
sludge dewatering.  The plant  is designed to provide full secondary treatment
for 1.6 MGD dry weather flow with a hydraulic capacity of 8.0 MGD wet
weather flow.  Present dry weather flow is approximately .7 MGD.  Effluent
consistently meets standard secondary treatment requirements of 30 mg/1
biochemical oxygen demand and  suspended solids.

Wetlands

The wetland system covers 20.3 acres (8.2 ha) and consists of five inter-
connected areas with tributary edge habitat.  The total plant flow passes
through the ponds and marshes  into Peyton Slough which discharges into
Suisun Bay.  At present flow of  .7 MGD there is a ten day detention time.
Land useage is 27ac/MG .  At the design capacity of the treatment plant,
1.6 MGD, there will be a 5 day detention time and 12ac/foc .  This ratio  will
still provide for a beneficial habitat.
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 As  shown in Figure  1,  plant effluent is conveyed by gravity through an out-
 fall  pipe and  siphon under  Peyton Slough to plot D.   This area is  divided
 with  earthen dikes  in serpentine fashion.   This method of channelization
 directs  the flow through the emergent vegetation,  to guarantee adequate
 circulation.   The final  cell of plot D contains Ecofloats (EEC Company)
 which are strung across  the open water.  These devices are made of redwood
 bark, wood,  and  styrofoam for floatation.   They serve as artificial substrate
 or  habitat for aquatic invertebrates which  normally colonize the bottom muds
 and emergent vegetation.   Thus  they increase the numbers of organisms  which can
 live  in  open water  thereby  enhancing the food chain.

 The flow passes  from the Ecofloat pond over weirs  into plots C and E.   Marsh
 plot  E is planted to provide food for migratory waterfowl using water  grass
 and alkali bulrush  (Echinochloa crusgalli and Scirpus robustus).  Since the
 District wetlands are  located on the Pacific Flyway the possibility exists
 to  feed  many migratory waterfowl.   Marsh plot C is  open water with four
 vegetated islands which  provide food,  cover and nesting sites removed  from
 predators.

 The discharges from plots C  and E are  combined and  flow by gravity through
 the inverted siphon to the  slough from which the flow is directed  to both
 plots A-l and  B.  Flow through  the  wetlands system  is entirely by  gravity.
 Dinges^-  points out  that high pressure  pumps and excessive velocities should
 be  avoided  since  they  harm  aquatic  invertebrates which are important for
 maintaining  a  balanced ecosystem.   The water level  in each plot is controlled
 by  adjustable  weirs  and ranges  from .3-lm.

 Plots  A-l, A-2, and  B  formed the  original wetlands  system whose objective
 was to compare the  creation  of  vegetated versus open  water habitats.   It
 was determined that  both  types  were  successfully created and  that  the
 combination provided a more  stable,  total habitat than either type alone.
 Plot  B is mixed open water and  emergent vegetation.   Plot A-l contains
 emergents and A-2 is an open water  area with supplemental invertebrate
 habitat.   Large open water areas  are  particularly important  in attracting
 migratory ducks,  the area must  be visible to the waterfowl while  flying.
 The flow is discharged to Peyton  Slough from plots A-2 and B.

 WATER QUALITY CHARACTERISTICS

 The wetlands environment has  a  positive effect on the treatment plant
 effluent.  Various monitoring programs  have been carried out  during the
 life  of  the project  to assess the water quality within the wetlands and  also
 the quality of water discharged  from the system.   The local  climate is
mild,   average daytime  water  temperature is  19°C, range 5-29°C.   The pH
 normally  remains  between  7.0  -  7.4  units; increases up to 8.8 units  occur
 accompanying algal  blooms.   The District treats  only  domestic wastewater
 with very low metal  content.  Therefore, the  wetlands  is  not  monitored  for
metals.  Disinfection  with chlorine  to  achieve  a total  coliform level  of 23
 MPN is accomplished  prior to  the  wetlands.   The  initial  portion of plot  D
 is  used  for dechlorination,   the  residual entering D  is  1.0-4.0 mg/i.  APHA
 Standard Methods, 14th Edition  procedures are  referenced  for  each  analysis.
 The data  discussed  is  on only plots  A-l, A-2  and B, which have  been in
 operation since the  fall of  1974.   Plots C,  D,  and E  were constructed  in
 the fall  of 1978  and are now being monitored.
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Dissolved Oxygen

The levels of dissolved oxygen (DO), measured with a portable meter (method
422F), vary diurnally and seasonally from about l.Omg/1 to supersaturation.
Normally levels above 5mg/l are maintained.  Due to the shallow depths and
frequent wind mixing, the dissolved oxygen levels do not become stratified.
The highest levels of DO are caused by algae and occur in summer months.
The lower levels of DO occur in the early morning hours.  In general, the
DO in winter months has a lower, smaller range.  Even with the wide range of
DO levels there have been no odor problems or anaerobic conditions associated
with the wetlands.

Biochemical Oxygen Demand

Figure 2 shows biochemical oxygen demand (BOD, method 507) and suspended
solids data in six-month intervals divided into growing season and non-
growing season.  The water quality in a biological system, such as the wet-
lands, is affected by the seasonal life processes occurring there.  The
average BOD loading rate is 172 Ibs/day and has been consistently reduced
by marsh B; only in two six-month periods did the BOD remain the same as
it was in the plant effluent, i.e., influent to the wetlands.  The A complex
reduced the BOD in the winter months and the summer of 1977, but raised the
BOD during the other two summers.  It must be stressed, however, that the
type of BOD leaving the treatment plant and that leaving the marsh system
differ.  Materials comprising the BOD in the plant effluent are the degrada-
tion products of human waste.  The material exerting a BOD in the marsh
effluent is partially composed of algae and other living organisms at the
very base of the food chain.  These constituents are ready to be used by
organisms downstream whereas the materials in the plant effluent are not yet
in a usable form.

Suspended Solids

Suspended solids (SS, method 208 D) data for the four years to date show
that in the strict sense, SS are usually reduced in the winters but not in
the summer.  The average loading rate to the wetlands is 189 Ibs/day.  When
SS leaving the wetlands are higher than the values found for the plant
effluent it can be attributed to algal growth in the pond-like portion of
system or silt from winter runoff.  Therefore, it is especially important  to
acknowledge the form in which the SS leave the wetlands because algae com-
prises the producer level of the food chain.  This producer status means
that the algae is the base of the food pyramid allowing a healthy, balanced
ecosystem to occur in the marshes and slough.

When the results of plots A and B are compared it is apparent that if water
quality criteria are placed on a wetland discharge, the system should be
designed with a vegetated cell last in the flow scheme.  Binges3 work with
floating vegetation and Spangler et al^ working with emergents have both
concluded that aquatic vegetation is an effective means of improving various
water quality parameters.
                                      63

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 Nutrients

 Nutrient  levels  in the  plant effluent are variously affected by the  wet-
 lands.   In some  cases nutrients  are removed and in others,  levels  remain
 unchanged.   The  nutrient  analyses  were run on grab samples  collected during
 1975-1978,  using the  following methods:   nitrate 419D,  ammonia 418B  with
 distillation,  total organic nitrogen 421, total phosphate 425F.  Table  1
 gives  the  average,  range  and percentage  of wetlands samples  that had a  lower
 level  of  the nutrient than did the plant effluent sample on  the same day.
 Consistent  nitrate  removal is accomplished by the wetlands.   Nitrification
 does not  occur to any great extent.   Phosphorus does not appear to be a
 limiting  nutrient,  the  amount entering is also discharged.   There  is a
 great  deal  of biological  activity  in the wetlands,  a balance seems to be  in
 affect such that nutrients are neither added to nor extracted from the
 system.   The exception  to this is  the consistent reduction of nitrate levels.

 THE HABITAT

 Numerous  ponds,  marshes and rivers in the United States are  fed, in  part,
 with treated wastewater.   The unique aspects of this project are 1)  a wet-
 lands  exists where  previously there  was  none,  2) the sole source of  water is
 treated wastewater, 3)  the primary purpose for creating the  wetlands is to
 provide wildlife habitat.   The major goal of this research has  been  to  de-
 fine the components of  this newly  created wetland habitat.   Only after
 defining what  exists can  one then  proceed to determine  success  or  failure of
 the project.   The habitat  types which comprise the  wetlands  are  1) open water
 alone  or in combination with ecofloats or islands,  2) areas  covered  by  float-
 ing vegetation -  either free floating such as  Lemna sp. or rooted  on the
 levees and  floating 2-3 ft.  out over the water,  3)  areas of  emergents,  4)
 cultivated  waterfowl food  area and accompanying mud flats, 5)  levees and
 adjacent land  with grasses,  bushes  and some  trees.

 Vegetation

 A wetlands  community is complex and  is composed of  both terrestrial  and
 aquatic forms  of plants and  animals.   There  are more than 72  species  of
 macrophytes  in the MVSD wetlands,  none were  planted by the District.  Twelve
 of these are emergents:  Typha  spp. ,  Scirpus  spp.,  sedges; another  10 are
 particularly saline tolerant,  29 are  native  to California.   In  the early
 1800"s the  site was covered  by a brackish water marsh, which was later
 diked and drained.  This accounts  for the saline  nature of the  soil.  The
 remaining plants are field  annuals,  perennials,  herbs and shrubs.  The
vegetation  serves as food,  shields animals  from predators, provides  nesting
 sites and improves some water  quality parameters.   Nineteen  of  the species
have seeds  that are used by  waterfowl  for food.5  As winter  progresses  food
becomes more scarce and the  birds  and animals  eat many plants or plant  parts
not otherwise eaten.  Planting the 2.5 acre  plot  E  in seed producing  vegeta-
 tion will expand the available food  supply.

An open water area mixed with  stands  of  emergent  vegetation  provides  the
habitat necessary for a greater variety  of organisms.  This diversity and
 interdependence  of plant and  animal  species  leads  to ecological stability.
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The surface area of the wetlands is approximately 63% open water combined
with 37% covered by emergent vegetation.  Voigts notes that this inter-
spersed type of habitat fosters a great variety of aquatic invertebrates and
also appears to attract the greatest variety of nesting birds.   In a
biomass study done on this emergent vegetation it was found that Typha
latifolia can produce up to 18 Ibs/sq m and Scirpus californicus up to
24 Ibs/sq m, both as dry weight.

Algae.  The algal growth in the wetlands is highly beneficial.  It oxygenates
the water, removes ammonia, and serves as a food source for small herbivorous
animals such as the zooplankton.  The wetlands system has never been plagued
by the growth of nuisance algae:  no filamentous mats, no blue-greens, no
odor producers.  The dominant algae present over a two year period were:
euglenoids, chlamydomonids, chlorella-like, and naviculates.  Light and
dark bottle productivity analysis has been carried out over a two year
period.  The low temperatures and overcast conditions of winter keep produc-
tivity very low to non-existent.  During the summers studied, 1977 and 1978,
algal growth was cyclical.  However, numbers of algal cells,  therefore
oxygen evolution, was much greater in 1978.  It is theorized  that this
increased number of cells can be accounted for by the decrease in zooplankton
population and other algal predators.  The decrease in the zooplankton was
due to the increased number of mosquito fish (Gambusia afinis).  This
is a humanly created upset in the ecological balance of the wetlands.  Marsh
management techniques provided the increase in mosquito fish, which success-
fully eliminated mosquito breeding.  However, it also had this marked affect
on algal growth.  During the fall of 1978 as many as 52 common and snowy
egrets were feeding on the mosquito fish, in a four acre area.  Some of the
excess fish were trapped by other local agencies.  It is hoped that in the
coming year a balance can again be reached between the numbers of fish and
invertebrates.

Animals

Twenty-two species of animals live at the MVSD wetlands:  10  species of
mammals, 4 sp. of amphibians, 4 sp. of reptiles, 3 sp. of fish.  Rask studied
the south levee of plot B and found heavy use by mice (Mus musculus and
Reithrodontomys megalotis) and muskrats (Ondatra zibethica).? The animal  list
includes both herbivores and carnivores; many of the species  reproduce and
live solely on what exists in the manmade wetlands.  All of these animals
have come to the District on their own.

Birds.  Ninety species of birds either live in or stop at the wetlands during
migration.  This is a very large variety for such a small area, clearly wet-
lands are critical in the San Francisco Bay area.  Schulenburg estimates  that
70% of California's wetlands have been lost to draining and filling, since
the turn of the century."

An approximate breakdown of species composition is 15 sp. of  ducks, 32 sp.
of water and shorebirds, 30 passerine  species, and 6 sp. of  raptors.
It appears that many of the migratory birds return each year.  If it is not
the same individuals it is at least the same species returning at the same
time each year.  In some cases  these birds are somewhat uncommon in the
locality, which leads the author to believe it is the same  flock returning,
                                           65

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 for example tri-colored blackbirds.   There are two types of usage of the
 wetlands by migratory birds.   Some flocks will stay only a few hours or less,
 other flocks will spend weeks or months at the wetlands before moving to
 their destination,  usually Canada or Southern California.   For example, a
 flock of approximately 90 ruddy ducks spent two winter months  whereas a pair
 of mallards spent only one morning.   Predatory birds,  for  instance herons
 and hawks,  need  a large range and the MVSD wetlands is included in the
 territory they rely on for food.   There are a number of bird families in
 which many  generations have hatched,  grown and reproduced  entirely dependent
 on the wetlands.  A successful nesting this spring, 1979,  of cinnamon teal  will
 be the fourth generation.   The quality of the water and chemical  content of
 the vegetation must be acceptable since it enables the organisms  feeding on it
 to continually produce viable offspring.   The available food supply appears
 to define the carrying capacity of the wetlands,  for birds.   This is why
 the cultivation  of  seed bearing plants was initiated.

 Aquatic  Invertebrates.   There are more than 34 species of  aquatic inverte-
 brates living in the  wetlands:   8 sp.  of  bugs and  beetles,  10  sp.  of flies,
 7  other  insects,  5  sp.  of zooplankton,  4  sp.  of non-insects.    Voights study-
 ing four  marshes  in Iowa found the number of taxa  present  to be between
 20-32, with a maximum of 43.6  This  is  clear evidence  that  a species list of
 34 is  comparable  to that found in other small wetland  areas.   It  is probable
 that  there  are more species than  have  been identified  of zooplankton,  due
 to the difficulty of  identification.   Nearly all of these  organisms exist in
 the wetlands  in  each  of their life stages.   For these  organisms to be able
 to reproduce  successfully  generation  after generation  they  have to be living
 in high quality water.   The volume of  invertebrates and the  species diversity
 also  are  clear indicators  that a  stable ecosystem  has  been  created.   During
 the summer  of 1977  up to 3.8  Ibs/hr.  of zooplankton, mostly  Daphnia,  were
 trapped in  the outlet weir  of plot A-2.   This is a considerable volume of
 food  available for  use  by  larger  invertebrates  and fish living  within the
 wetlands  and  downstream.

 WETLANDS  MANAGEMENT

 A  well designed project  reduces the amount  of necessary maintenance.   The
 major  design  objective  is  to  create a  balanced  habitat  and  avoid  nuisance
 situations.   Much was  gained  during the first four years of  operation of
 plots  A-l,  A-2,  and B.   This  knowledge  was  incorporated in  the  design of the
 three  areas added in  1978.

 Levees

All levees  should be  wide enough  for vehicular  traffic  so  they  may  be
utilized  for maintenance when necessary.   Some  levees  are used  on  a regular
basis, others are not and vegetation  is allowed to cover them.  These  vegeta-
 tion covered  levees add  to the habitat  but  provide  access when  needed.
Levees should be at least 10'   wide, steep-sided, with  1.5'  freeboard,  and
 compacted during construction.  There are many  wetlands  organisms which
 tunnel in levees:  muskrats,  gophers, crayfish, and  other small mammals.
Therefore proper levee design and  construction  is  crucial to keeping
maintenance needs minimal.
                                     66

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Erosion

Vegetation is the main form of erosion control and works quite well once
established.   A minimum of one spring and summer are needed before the
vegetation can become established, without specific planting and cultivation.
Vegetation is not sufficient around weirs, gates and pipes.  These areas
must be fortified with riprap.  The District is fortunate in this respect
because it is located en route to the local landfill and gets all its riprap
free of charge.

Plot Design

By dividing the total area designated for the wetlands into plots more
habitat goals may be achieved.  When a multiple plot system is created flow
variation is  facilitated.  This allows one plot to be isolated from the system
in case of major maintenance needs.  Multiple plots also allow depth variation.
Depth is a key factor in habitat design:  it will determine whether or not
emergent vegetation will be present and will affect temperature and dissolved
oxygen values.  Plot shapes may vary but small, constricted areas should be
avoided as they would promote stagnation and vector problems.  Deciding
which groups  of organisms are desired in the wetlands and knowing what condi-
tions these organisms normally live under will determine the fundamental com-
ponents of the design.

Vectors

Botulism.  Clostridum botulinum is the cause of avian botulism and will not
cause botulism in humans.  It is, however, deadly to waterfowl and certain
measures may be taken to avoid its occurrence.  There have been no known
cases of avian botulism at the MVSD wetlands.  Avoiding anaerobic conditions
by keeping the water circulating and maintaining the depth under 3' is an
important factor in botulism avoidance.  Removal of floating organic debris
which collects behind weirs and in corners is regularly done.  Steep-sided
levees, adjustable broad crested weirs for controlling water levels, conveying
water by pipeline, and ability to shunt a plot out of service for draining,
are also factors in the botulism avoidance program.

Mosquitoes.  Mosquitoes lay eggs in water and the larva grow there under-
going metamorphosis to the adult form.  To breathe the larva must hang from
the surface film of the water, piercing it with their respiratory tube
to obtain oxygen.  This knowledge of the mosquito life cycle and habitat
needs helps the wetlands manager avoid mosquito breeding problems.  Open
water areas,  subject to wind action and providing easy access for predators,
limit mosquito production.  Maintaining good circulation in vegetated areas
provides for predator access and lessens mosquito production.  These factors
have been the key to MVSD success in keeping mosquito production minimal in
1978.  Figure 3 compares the numbers of adult female mosquitoes caught in a
light trap monitored by the Contra Costa County Mosquito Abatement District.y
The insects are collected and counted weekly, analysis began in August of
1976.  The drastic reduction in numbers of mosquitoes trapped in late summer
of 1977 and all of 1978 was due to the transplanting of mosquito fish
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 (Gambusia afinis)  in the early  summer of 1977.   Fish were  taken  out  of  Peyton
 Slough and stocked in plots  A-l,  A-2, and B.   By the end of the  summer
 their  numbers  had  increased  enough to have the  mosquito  larvae population
 greatly reduced.   Enough of  the fish  wintered  over  such  that  in  the  spring  of
 1978 they multiplied quickly and soon had the  mosquito  population under
 control.   The  rise in numbers at  the  end of 1978 was due to water trapped
 on property adjacent to  the  District's.   Good  circulation  and adequate
 numbers of predatory fish have  allowed MVSD to  operate a wetland project
 which  does not produce vector problems.

 COSTS  AND BENEFITS

 The capital cost of  the  entire  20.3 acre wetlands was $94,000.  Average annual
 operation and  maintenance expenditures over 4.5  years have  been $l,200/yr.
 Additional to  this figure would be salaries for  approximately 10 hrs/wk of
 system maintenance and 15 hrs/wk  for  monitoring  and  management.  No  pumping
 costs  are associated with the gravity flow wetlands  system.  The amount of
 time necessary by  personnel  depends on the amount of monitoring required
 and on maintenance needs  which vary seasonally and can be  greatly reduced by
 careful design of  both the hydraulics  and  physical features of the system.

 Benefits  of the wetlands  system using treated wastewater include improved
 water  quality,  habitat creation,  and  recreational and educational opportunities.
 The wetlands is MVSD's contribution to the community, and  it receives heavy
 use.   The  recreational and educational  benefits  included in the wetlands
 are a  good example of  the  intent  of section 201(g) (6) of  the Clean Water
 Act of 1977  "The Administrator  shall  not make grants...(for) treatment
 works  unless the grant applicant has  satisfactorily  demonstrated  to the
 Administrator  that the applicant has  analyzed the potential recreation and
 open space  opportunities  in  the planning of the  proposed treatment works."
 There  are  visitors of  all  types ranging  from neighborhood  children who look
 for animal  tracks  to  organized group  tours  for college students and environ-
mental  groups.  The District has hosted  researchers, municipal officials,
 and nature  photographers.  The local Audubon Society gave  the District an
 award  for  its work and has declared the wetlands to  be one of the best birding
 areas  in  the county.   The California  Chapter of  the  Soil Conservation Society
 of America has  also  officially commended the District for  its work on water
 reuse  and habitat  creation.  There is  broad recreational potential in this
 type of water reuse project.   Table 2 delineates the hourly usage of the
wetlands by the public.

A wetlands system  also has income  possibilities.  For example, during the
summer  of  1978  there was an over abundance  of mosquito fish in the ponds.
The local mosquito abatement  district  seined fish out of the ponds for their use
A local wildlife rehabilitation center and museum collects  fish as well as
duckweed and invertebrates for animal  food.  The District could charge for
the fish and other food products produced.10  The possibility exists to sell
crayfish for bait or aquatic  invertebrates  for tropical fish food.  •*•  An
option   for a large wetlands would  be to rent a portion of it to a duck club
for hunting.

CONCLUSIONS

The protection, restoration and enhancement of wetlands has become a national
goal.   The potential environmental benefits derived  from utilizing treated
municipal wastewater  for wetland restoration and enhancement has  been

                                    68

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demonstrated by the Mt.  View Sanitary District's wetlands project.  The
project also demonstrates a reuse method that combines wastewater and wild-
life management for optimum results.  Wetlands systems created and main-
tained with treated wastewater are cost-effective and low in energy require-
ments.  (1) A balanced and healthy wetlands ecosystem, composed of pond and
marsh areas, has been successfully created using secondary treated wastewater.
(2) The wildlife habitat actively supports 72 sp. of plants, 21 sp. of animals,
90 sp. of birds and 34 sp. of aquatic invertebrates.  (3) Mosquito breeding
has been reduced to a minimum through the use of natural predators.  Avian
botulism and odors have been avoided.  (4) Redwood bark floats provide
supplementary habitat for aquatic invertebrates, thereby increasing their
populations in open water.  (5) Nitrate removal is consistent.  BOD and SS
removal is seasonal - if algae was not regarded as a component of SS they
would then be consistently lowered.  (6) Public support for the wetlands is
strong, educational and recreational usage is considerable and increasing.
PART 2 MARSH-FOREST PILOT PROJECT

In December 1978 EEC Company initiated a pilot project at Mt. View Sanitary
District.  The objectives of this marsh-forest project are to 1) combine
wetland and upland habitats, 2) to improve the water quality of the secondary
effluent coming from the treatment plant, 3) to produce a cash crop of waste-
water irrigated redwood trees.  Figure 4 shows the marsh-forest layout.
The pond is 20' x 40' x 3' and the forest is 40' x 100'.  The pond receives
3600gpd of secondary effluent, the water is then pumped to the underground
irrigation system which consists of lV PVC pipe connecting K-6 infiltration
units under each tree.  Water passing through the irrigation system is col-
lected in a splitter box from which some is discharged and some is recirculated,
Water quality analyses are performed on the water in this final splitter box:
averages of weekly analyses for 8.5 months show BOD and SS levels at 8.1 mg/l
and 6.2 mg/l respectively.  The redwood trees have grown 1.5' in 7 months.12
The project appears to be meeting its goals of producing a high quality
effluent and the irrigation system is functioning well.  The trees are grow-
ing rapidly.  Eight varieties of aquatic invertebrates have been identified
from the duckweed covered pond.  The system will continue to be monitored
on a weekly basis for BOD and SS, monthly for nutrients, color, turbidity,
and TDS.
                                       69

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 TABLE  I.  WETLANDS  INFLUENT AND EFFLUENT NUTRIENT LEVEL AVERAGES, 1975-1978.
            Average  (mg/1)           Range  (mg/1)           % Reductions3
Nutrient    Influentb    Ac    Bd    Effluent    A and B    A      B
N03-N
NH3-N
Org-N
P04
7.4
7.9
4.8
9.9
3.3
6.7
4.4
9.1
1.7
6.8
4.6
10
.55-18
.24-15
.4-14
.44-18
.06-16
.1 -19
.09-17
.48-18
90
60
56
53
97
56
63
37
a) This is the percentage of samples when the marsh discharge was lower
   than the marsh influent, i.e., plant effluent.

b) Wetlands influent is secondary treatment plant effluent.

c) Effluent of plot A.

d) Effluent of plot B.
TABLE II.  PUBLIC USAGE OF WETLANDS (HOURS).
Year	Education    Recreation    Total    Hours/acre*

1977           292           280        572         52
1978           524           291        815         74
*Unexpanded system of 11 acres.
                                     70

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                                                             tc*Li - rirt
                                      srre PLAN
                                  KT. VIEW **MITAWY DISTRICT

                                 MAftSH ENHANCE MCNT PftOGAMI
                     Figure  1  Wetlands  Plot  Plan
o

2
80









60









40




30




20
     _BOD
       (6 mo. ovg.)

              i 10  • J
                           o
                        *x  o

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60
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20
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SOLIt
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i
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L ovg.
-V
,
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«
<^^



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/
^


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//
\ \y'/

•* 	

                           SEC. EFFLUENT ENTERING  MARSH
                 	EFFLUENT FROM  MARSH A

                 	 EFFLUENT FROM  MARSH B




             FIG. 2  Biochemical  Oxygen Demand and Suspended Solids Data
                                                71

-------
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-	—  1976
	  1977
	I97S
JUNE   JULY    AUG.    SEPT.
           FIGURE  3
      MOSQUITO  PRODUCTION
                                         SECTION IS--!!
                                       SPLITTER BOXPFTAJ
     FIGURE 4 tUnh-Forc.t Layout

-------
                                 REFERENCES


1.   BINGES,  RAY.   "Wee Beasties May Improve Your Effluent."
     Water and Wastes Engineering.   12(3):35-37.   (March 1975).

2.   DEMGEN,  FRANCESCA C.  and J. WARREN NUTE, INC.  Marsh Enhancement Program
     Conceptual Plan.  Mt.  View Sanitary District of Contra Costa County,
     California.  (November 1977).

3.   DINGES,  RAY.   "Aquatic Vegetation and Water Pollution Control.   Public
     Health Implications."  American Journal of Public Health,  68:1202-1205 (1978)

4.   SPANGLER, FREDERIC R., WILLIAM E. SLOEY, C.W.  FETTLER, JR.   "Wastewater
     Treatment by  Natural  and Artificial Marshes"  September 1976.
     U.S. EPA, Ada, Oklahoma 74820.

5.   DEMGEN,  FRANCESCA C.   Biological Monograph:   Containing supplementary
     biological data of the Mt.  View Sanitary District wetlands system as
     related  to literature search findings.  Mt.  View Sanitary  District.
     October  1978.

6.   VOIGTS,  O.K.  "Aquatic Invertebrate Abundance in Relation to Changing
     Marsh Vegetation." American Midland Naturalist. 95(2)313-322.  (April  1976).

7.   RASK, LAURIE  MACDONALD   Mammalian Inhabitants and Microhabitat Use
     at a Freshwater Marsh Maintained with Wastewater Treatment Plant Effluent.
     June 1,  1978.

8.   SCHULENBURG,  BOB.  Preserving California's Wetlands.  Outdoor California.
     Sept.-Oct. 1976 p.6.

9.   Mosquito light trap data courtesy of Chuck Beasley, PhD entomologist
     for the Contra Costa County Mosquito Abatement District.

10.  COLEMEN, MARK S. et al.  Aquaculture as a Means to Achieve Effluent
     Standards.  Oklahoma State Dept. of Health.  Excerpted from project
     reports  and reprinted for:   Hinde Engineering Co., P.O. Box 188, High-
     lands Park, IL  60035.

11.  Local tropical fish stores have shown an interest in buying packaged,
     sterile Daphnia for 40c/2 ounces.  Peak Daphnia production yields 3.8
     Ibs/hr.

12.  J. Warren Nute, Inc.   Marsh-Forest Demonstration Project Feasibility
     Assessment.  1979.
                                           73

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CYPRESS WETLANDS  FOR  TERTIARY  TREATMENT
                                       by
                     Walter R. Fritz, PE, Principal Engineer
                                      and
                  Steven C. Helle, PE, Associate Civil Engineer
                           BOYLE  ENGINEERING  CORP.
                           3025  East  South Street
                           Orlando, FL.   32803
In 1973, a team of environmental scientists,
under the direction of Dr. Howard T. Odum
and Dr. Katherine Ewel at the University of
Florida's  Center for Wetlands,  developed
the concept of using cypress wetlands as a
natural tertiary treatment mechanism for
domestic wastewaters. Working under grants
from the National Science Foundation and
the Rockefeller Foundation, they initiated a
field  investigation of the method. This dem-
onstration project  included an  intensive
examination of two cypress domes which
were supplied with effluent from a small,
extended aeration,  secondary  treatment
plant  at Whitney Mobile Home Park  near
Gainesville, Florida. The findings from these
domes were compared to the findings  from
a third dome which was supplied with  pure
groundwater and a fourth dome which was
left in its natural state as "control". Results
of the research show that the two "sewage
domes" effectively  treated  the effluent to
well  within acceptable tertiary treatment
standards with no significant adverse effect
on the environment.

By 1976, the sponsors at the National Science
Foundation were so encouraged with these
results that they provided Boyle Engineering
Corporation with a  grant to convert  the
existing research into an applied engineering
science suitable for implementation.  Boyle
engineers developed a three-phase approach
to this project:

  Phase 1—Develop conceptual techniques
           for using cypress wetlands for
          tertiary treatment.

  Phase 2—Determine the feasibility of
          utilizing the method.

  Phase 3—Develop procedures and prelim-
          inary regulations for implemen-
          tation.

This article will address  Phases 1 and 2.

Types of Cypress Wetlands

There are three basic types of cypress wet-
lands: domes, strands and fringe.

A cypress dome is a roughly circular-shaped
cypress swamp, one to twenty-five acres in
size, occupying a  shallow, saucer-shaped
depression which receives water from sur-
rounding  higher grounds.  The  trees  are
tallest in the center of the area, giving the
impression of an inverted  bowl  or dome.
The  ecosystem supports  lush  vegetation
including cypress trees.
                                            75

-------
 A  cypress  strand  is  a diffuse freshwater
 stream flowing through a shallow  forested
 depression  on a gently sloping plain. Be-
 cause of the water's  relatively low erosive
 powers, vegetation  can grow in  the river
 bed, further slowing water flow and spread-
 ing it over a wide area. Marshes may cover
 shallower  parts  of  the depression  with
 cypress forest in  the deeper  channels.

 Lake fringe or riverine cypress are located
 at  the edge of lakes or rivers. These types
 of  cypress  wetlands  are  not suitable  as
 treatment facilities since they offer no  re-
 tention time  before  entering open water-
 ways.

 Concepts  of Using Cypress Wetlands
 for Tertiary Treatment

 "Natural  Dome"  Concept  This   concept
 requires little  or  no  modification to  the
 cypress  dome  or  surrounding area  (see
 Figure 1). Treated wastewater is applied to
 the center of  each  dome and allowed  to
 pond or percolate  through the underlying
 soils to the groundwaters. Biological uptake
 from the vegetation, combined with  filtering
 action  from  the  organic layer,  removes
 essentially all nutrients, heavy metals, and
 coliform bacteria  from the  effluent.  Al-
 though  not yet conclusive, virus contamin-
 ation appears to be effectively absorbed  by
 the shallow  sandy layer immediately under-
 neath the mucky organic floor of the dome.

 "Isolated Dome" Concept  In their natural
 state, cypress domes  collect storm  run-
 off  from surrounding  lands, occasionally
 filling to capacity and spilling over onto
 surrounding areas. If wastewater is applied
 to the dome, problems may arise from over-
 flow  in  certain  situations.  The  Isolated
 Dome treatment concept virtually eliminates
 the  possibility of spillover, making  it a zero
discharge system. Isolation  is accomplished
by  constructing an earth dike around the
 perimeter, thus preventing surface waters
from filling the dome and dome waters from
escaping (see Figure 2).
 Flow Through  Systems  In  a third  treat-
 ment concept, the  secondary effluent  is
distributed  along the  upstream side of a
 cypress strand  and allowed to sheet-flow
 through the  strand  (see Figure  3).  The
 treatment  mechanism relies on  biological
 uptake by  vegetation and  the absorptive
 action of the underlying organic layer during
 overland flow. Discharge is into downstream
 waterways  rather than percolation to ground-
 waters as  in the previous  two  concepts.

 Feasibility Criteria

 Cypress wetland treatment of wastewater
 will be feasible only if it compares favor-
 ably  over  a broad spectrum of variables
 with  other  tertiary treatment  alternatives.
 The following series of questions (or criteria)
 must be answered in order to avaluate the
 attractiveness of the cypress wetland treat-
 ment alternative.

   'Will the  use of  the method  attain re-
    quired treatment results?
   'Are the costs competitive with other
    available treatment methods?
   * Are the costs and availability of required
    energy sources reasonable?
   "What are the environmental effects on
    the dome and surrounding ecology?
   • Is the method reliable?
   "Is the method available to a significant
    number of users?
   ' Under what conditions  (rules) will regula-
    tory agencies allow  the use  of  the
    method?

Treatment Results

The main  purpose of tertiary treatment  is
the removal of nutrients, primarily nitrogen
and phosphorus.  Normally,  tertiary  treatment
will also remove additional  amounts of BOD,,
suspended solids, heavy metals, viruses,  and
coliform bacteria which are  left  from  the
secondary treatment process. Research from
the Center for Wetlands' demonstration  pro-
ject clearly  shows excellent  treatment re-
sults. The  research determined  that 98  per-
cent of the total  nitrogen and 97 percent of
the total phosphorus  was removed before
the treated  wastewaters entered the under-
lying  groundwater. The concentrations of
nutrients and all other monitored parameters
in  the groundwaters under and surrounding
the sewage domes remained essentially the
                                        76

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 CYPRESS WETLAND TREATMENT CONCEPTS
    OCCASIONAL
RUNOFF  SPILLOVER
AUTOMATIC VALVE
AND TIMER

 OCCASSIONAL SPILLOVER
                                -  'EFFLUENT
                                 1 FORCE MAIN
                             ORGANIC LA Y£»
 Figure 1

 Natural
   Dome
Concept
                 »x CLAYEY N,
                   SANDS
                                 AUTOMATIC VALVE
                                 AND TIMER
                                     SECONDARY
                                     EFFLUENT
                              ORGANIC FORCE
                              LA YER  MAIN
                Figure 2

                Isolated
                  Dome
               Concept
                 CYPRESS STRAND
OUTFALL
      OVERLAND SHEET FLOW-
                   ORGANIC LAYER'
                                   MANUAL
                            FORCE MAIN  SECONDARY
                                   EFFLUENT
                Figure 3

                   Flow
                Through
                System
               Concept
                LITTLE OR NO PERCOLATION
                             77

-------
same as background and measured levels in
the control domes. Thus,  the groundwater
quality  remained well within Federal  Drink-
ing Water Standards.

Similar results were achieved in a mixed hard-
wood (with some cypress) "flow  through"
system  near Wildwood, Florida.  In this sys-
tem, which is receiving effluent from a muni-
cipal  secondary treatment plant, nutrient
concentrations  in  the lower part of  the
swamp  were  similar  to  or less than con-
centrations  in control areas and  in Lake
Panasofkee, into which the swamp drains.
This combined secondary  treatment  plant-
wetland system achieved results well within
Florida Advanced Waste Treatment Standards.

Cost-Effectiveness

Cypress wetlands  must  be economically
attractive, compared to other tertiary treat-
ment  methods, in order to be considered a
viable alternative. The cost-effectiveness of
cypress  wetland treatment  is  highly site
specific, with the cost of land, length of
required force mains, average daily  waste-
water flow, the type of cypress wetland and
surroundings all being important variables.
General cost analyses performed  by  Boyle
engineers demonstrate cypress wetlands to
to be cost-effective with  certain  combin-
ations of these variables (see Figures 4-7).

Another cost analysis  for an anticipated
treatment system in Waldo, Florida  indicates
tertiary  treatment by cypress wetlands to
cost 42.2i per  1000  gallons  compared  to
63.0c for spray irrigation and $1.07  for  a
physical/chemical treatment facility.

Cypress strands seem to offer an economic
advantage over cypress domes because they
are more often available in larger contiguous
areas. In many cases, the entire wastewater
flow could be served by a single cypress
strand,  as opposed  to multiple cypress
domes.  This  minimizes the total length  of
required force  main and wetland perimeter
which  often  must be diked or fenced.  In
another site specific cost analysis, the  costs
of both of these cypress wetland methods
were compared for a treatment facility near
Orlando, Florida. The results of this analysis
revealed that it would cost 22.3c per 1000
gallons  to use  a large wetland strand com-
pared to 71.2


-------
dominant energy form for cypress wetland
treatment. Wetland vegetation  uses the
energy from the sun and the nutrients from
the wastewater to grow and thrive, requiring
neither purchased fossil fuel energy nor syn-
thetic chemicals. However, if wetlands are
used as part of the treatment process, some
purchased energy must  be  used to pump
the treated wastewater to the wetlands, and
chlorine  may  be required for  disinfection
prior to application.

An analysis of the cypress wetland, physical/
chemical, and upland spray  irrigation alter-
natives was conducted to quantify and com-
pare purchased energy  requirements. The
results of  this analysis  indicate that  wet-
land application is generally more energy-
efficient  than either physical/chemical treat-
ment or spray irrigation because it involves
no  power  for aeration beyond secondary
treatment,  nor does it require any residual
head for spraying.

Environmental Considerations

Cypress  wetlands are  tender wetland  eco-
systems  which have often been  neglected
or abused. It  is  of  utmost  importance  to
consider the impact on  all aspects  of the
environment within and  surrounding each
wetland  prior  to  the application  of  waste-
waters.

Many of  man's surface drainage control de-
vices, such as canals, drainage  ditches and
the straightening  of  rivers, interfere with
natural recharge mechanisms, seriously en-
dangering groundwater levels and supplies.
Cypress domes serve as a reservoir system
by releasing  stored  surface waters  slowly
through the  organic  layer into  the  under-
lying sands during times when groundwater
is in short supply. The application of waste-
water assures a nearly  constant surface
water supply which has a mollifying effect
on groundwater levels, balancing them be-
tween wet and dry seasons. Further benefit
is derived by reduced fire danger to the dome
and surrounding vegetation.

In certain situations, occasional overflows
of the treatment dome waters may be a pro-
blem. Where unfavorable  conditions exist,
the problem  can be  solved by  the  imple-
mentation of  the "Isolated Dome" treatment
concept.

Cypress domes  and underlying  sandy  clay
soil layers have been very effective  in pre-
venting coiiform and virus contamination of
groundwaters directly under the  domes, un-
less the upper soil levels within the wetland
are significantly disturbed. In  one case, at
the Center for Wetlands  project, a mild in-
trusion of fecal conforms, 8 to 100  per 100
ml, was detected as a result of overflow  onto
highly porous soils. Bacterial and viral  con-
tamination of groundwaters appears not to
be a problem if  the wastewater which is
applied  to  the dome is  sufficiently chlor-
inated and all  possible "short-circuits"  to
groundwaters are avoided.
                Figure 6

              COST CURVES — 1.0 MOO
I"
e
s-
        •CM ___ --'

        "«qi>il>-C2j2'''
                     S
              LCMOTH Of FOfKC UAIM, UMiCi
                 Figure 7

              COST CURVES — 1.0 MOD
                               LfOCHO
                                                            LINOTH Of fOHCC MAIN. MILES
                                               79

-------
 Cypress trees and other wetland vegetation
 appeared to suffer  no detrimental  effects
 from the introduction of wastewater.  Indeed,
 there is mounting  evidence that the  trees
 thrive in effluent. Analysis of the trees in a
 strand near Waldo, Florida shows that they
 grew 2.6 times  faster after the wastewater
 was applied.

 Introduction of  sewage effluent  to cypress
 domes initiates an immediate appearance of
 duckweed, which readily covers the entire
 water surface and serves a vital  role in the
 treatment process. The duckweed offsets a
 reduced treatment capacity of the dormant
 cypress  trees  during the winter months.
 Throughout the  year, the duckweed  utilizes
 nearly one-half of the applied nitrogen, two-
 thirds of the applied  phosphorus, and nearly
 all of the heavy metals. These materials  then
 become part of the organic layer in the wet-
 land  floor  through  decomposition, making
 them  available  to  the cypress tree  root
 systems.

 Reliability

 Wastewater  production  is   an  every  day
 occurrence, 365 days a year, requiring  waste-
 water treatment systems to be highly reliable.
 The  following criteria for evaluating  the re-
 liability of  a  land application tertiary treat-
 ment system has been established  by the
 U.S.  Environmental Protection Agency. These
 criteria apply equally  well  to  wetland ap-
 plication systems.
 The system must have the ability to meet or
 exceed treatment requirements. Center for
 Wetlands' results have shown a reduction in
 total nitrogen of 98 percent  and total phos-
 phorus of 97 percent for the combined se-
 condary  treatment facility/cypress  dome
 system. Essentially,  groundwater nutrient
 levels under sewage domes are the same as
 under control domes.
 Failure rates must be low. Cypress wetland
treatment requires little mechanical or elec-
tronic  equipment, minimizing the chances
of failure. The wetlands are always available
for full-time operation.
 The system must not be vulnerable to na-
 tural disasters. One natural disaster which
 could impair operation is a period of heavy
 rains, causing a temporary  spillover  from
 the  dome. Runoff waters during  these per-
 iods would serve as a dilution agent for the
 overflowing wastewaters, reducing the dan-
 ger  of contamination. The only other likely
 natural disaster affecting operation is forest
 fire. Studies after  fires  in cypress  domes
 demonstrate cypress trees have a remarkably
 high survival rate. In  addition, the constant
 presence of water in the domes substantially
 reduces the risk of fire.

 Adequate supplies of  required  resources
 must be available. The  only resources re-
 quired for cypress wetland  treatment are:
 1) wetlands, 2) sunshine, and 3)  power for
 the pumps. The first two occur naturally and
 the power requirements are much less than
 other tertiary treatment methods. There are
 no chemicals, other than chlorine, required
 for cypress wetland treatment.

 The  operation must  include a  sufficient
 factor of  safety.  Hydrogeologic  and  other
 prerequisite studies are  required to deter-
 mine the quantifying parameters for design.
 To prevent serious problems from unforeseen
 circumstances, factors of safety may be em-
 ployed by the designers  when calculating
 required wetland areas. Furthermore, holding
 ponds can be installed  to allow relatively
 even application of effluent and to prevent
 shock effect from peak loading.

 Availability

 In order for cypress wetland tertiary  treat-
 ment to be feasible, adequate cypress  wet-
 lands must be available to the secondary
 treatment facilities. To evaluate availability,
a survey of approximately 40 percent of the
existing wastewater treatment  facilities in
 Florida was conducted  to compare treat-
ment facility sites with the location of cy-
press and  other forested wetlands.  The
results of this survey can be extrapolated to
estimate availability for the entire state.

Based on  earlier portions of this  investi-
                                        80

-------
gation, each facility was considered to have
adequate cypress wetlands available to war-
rant further investigation into the feasibility
of  implementation,  if 300  acres  per mgd
(design flow) were located within a reason-
able distance. The following distances were
considered as reasonable:
  1 mile for design flows less than  0.1 mgd,

  3 miles for design flows between 0.1 and
  1.0 mgd, and
  5  miles  for design  flows over  1.0 mgd.
The following results  were  found from the
survey:
  • 253  out of 2327 surveyed facilities have
    adequate  cypress  domes.  These 253
    facilities  represent about 3 percent  of
    the total design flow.
  • 583  out of 1679 surveyed facilities have
    adequate  forested  wetlands  (cypress
    domes and strands, hydric hammocks).
    These 583 facilities  represent about 28
    percent of the total design flow.

These results indicate that adequate forested
wetlands are available for 35 percent of the
wastewater treatment  facilities  in Florida
with a combined design flow  of over 350 mgd.
If the method is restricted to cypress domes,
about 450 facilities, representing  43 mgd
design flow, can consider the wetland tertiary
treatment alternative.

Regulation

State and Federal regulatory agencies indi-
cate that they believe cypress wetland ter-
tiary  treatment shows  promise of  being a
viable tertiary treatment alternative. This  is
evidenced by  their support and interest  in
the Center for Wetlands' and related  pro-
jects. However, the general regulatory con-
census  is  that  it is  premature to  create
explicit rules  for implementation.  They do
support, however,  implementation  of the
method  on a case-by-case basis after demon-
stration of treatment results, environmental
concerns and cost-effectiveness.
Conclusions
The  Center for Wetlands' research clearly
shows cypress dome treatment to  be tech-
nically feasible as an alternate method for
tertiary treatment. Cypress domes are, how-
ever, restricted in their applicability  because
of low allowable  loading rates and  the rela-
tively small areal  extent of each dome. This
necessitates extensive force main networks
and creates large total perimeters to be diked
or fenced for all but the smallest treatment
facilities. Cypress strands, on the other hand,
are often fairly extensive areas which  will
probably allow larger wastewater flows to
be treated at a single site. A detailed scien-
tific  study of  loading  rates and treatment
mechanisms in a  cypress strand is currently
underway at Jasper, Florida under the direc
tion of Boyle Engineering Corporation.
This material is based upon research supported by the
National Science Foundation under Grant No. ENV76-
23276.

Any opinions,  findings, and conclusions or recom-
mendations expressed in this publication are those of
the author and  do not  necessarily reflect the views
of the National Science Foundation.
                                                81

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THE DRUMMOND PROJECT - APPLYING LAGOON SEWAGE
EFFLUENT TO A BOG: AN OPERATIONAL TRIAL

William M. Kappel, U.S. Geological Survey, 521 W. Seneca Street,
  Ithaca, New York  14850
INTRODUCTION

     The Town of Drummond is located in northwestern Wisconsin
approximately 70 miles southeast of Duluth, Minnesota, and within the
boundary of the Chequamegon National Forest.  The town has a residential
population of approximately 280, a regional high school population of
400, and one sawmill as its only industry.

     In 1971, Drummond was ordered by the Wisconsin in Department of
Natural Resources (WDNR), to develop a sewage treatment system for the
town.  Existing sewage treatment consisted of individual septic systems
which did not function correctly due to heavy clay soils.  This
condition necessitated the pumping of septic tanks at least twice a
year to prevent the discharge of primary effluent to stormwater
drainage ditches and Lake Drummond.

     A three-cell, contact stabilization system was developed for
secondary treatment of the sewage.  Twice a year treated secondary
effluent was to be discharged to the Long Lake Branch of the White
River, a class 1-A trout stream.  The U.S. Forest Service became
involved with the project because the proposed system was to be built
on Forest Service land.  Review of the Environmental Impact Statement
for the proposed project was not satisfactory to Forest Service
personnel, and after several meetings with town officials, the WDNR,
and agencies funding the project, it was decided that construction
would commence on the lagoon system, but a different alternative for
final effluent discharge would be found.

Alternative Analysis

     The Forest Service explored several different alternatives trying
to find a tertiary treatment system which would effectively treat the
effluent, protect the local and downstream environment and not add to
the construction costs of an already financially over-burdened town.
                                       83

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 The use  of  a  "natural"  treatment  system was considered as the best
 method to meet  the  above  objectives.  Most of the soils around Drummond
 are an organic  wetland  type,  therefore, these materials seemed to offer
 the best hope for treatment.

      After  an intensive literature review, several natural and artificial
 wetland  treatment systems were found.  The artificial wetland (Meadow-
 Marsh-Pond) system  developed  by Dr. Maxwell Small was considered, but
 the costs of  construction were too high.  The Cypress Dome studies in
 Florida, by Dr. Howard  Odum,  were also explored but here the costs of
 pumping  and maintenance of the piping system were considered too high.
 The Forest  Service  had  developed a tertiary peat-bed filter system using
 a layered,  grass over peat over a rapid sand filter, but again costs of
 construction  and maintenance  were considered too high for the town to
 carry.

      A fourth alternative which held some promise was the variable ditch
 systems  of  Finland.  These systems use a shallow feeder ditch to apply
 primary  effluent to a peat bog.  A deeper ditch approximately 20 to 40
 meters distant  draws the  effluent from the shallow ditch through the
 peat  and into the deeper  drainage ditch.  Thirty years of use in Finland
 with  good treatement results, made this system look viable,  until the
 costs of construction were calculated.

      At  this  time a similar ditching system was being operated at
 Bellaire, Michigan.  This system functioned for a time until a heavy
 rainstorm washed the ditch-system out.  Dr. Robert Kadlec of the
 University  of Michigan, had studied the Bellaire system and was working
 on  a  new system which was to be tried at Houghton Lake,  Michigan.  This
 system was  to disperse  secondary effluent to a wetland using a pipeline
 system.  Speaking further with the consulting engineering firm,  Williams
 and Works,  it was determined  that this system might be feasible at
 Drummond.

      Investigation at the 10 ha bog southeast of the lagoon construction
 site  at Drummond revealed that a gated irrigation pipe system could be
 used  to apply the sewage  effluent to the surface of this bog-wetland.

 Description of the Drummond Bog

     The Drummond area lies within the end moraine of the Cary-Valders
Advances of the Wisconsin Age Glacier; approximately 10  to 12,000 years
 B.P.  The area has a rolling topography with variable soil and vegeta-
 tive cover.   The treatment bog lies within a kettle-hole depression of
 approximately 25 ha in size.   The bog is perched above the local and
 regional groundwater system due to a natural clay "liner".   The  watershed
 surrounding the bog is 15 ha, with a vegetative  cover type of  northern
hardwoods,  oak and maple.
                              84

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     The bog is comprised of decayed organic matter,  as deep as  11
meters, with a cover mat of spaghnum moss species.  Vegetative
cover species consist of Black Spruce,  Tamarack (Larch), Leather
Leaf, Cranbury, and Blueberry.

     The bog is located in the upper reach of an un-named feeder to
the Long Lake Branch.  In this position,  outflow from the bog only
occurs during the spring snowmelt-runoff  period and occasionally
during heavy summer thunderstorms.  During other periods no outflow
occurs.  Water which does leave the bog flows down to the Weso
Lake, a small 2 ha lake which is surrounded by a sedge, cat-tail,
spaghnum wetland.  A wet weather outflow from Weso Lake moves into
another extensive wetland before entering the Long Lake branch in a
diffuse flow pattern.

Operation of the Bog Irrigation System

     Based upon the hydrology of the bog and the biology of the
eco-system, discharges to the wetland only occur between mid-april
and early November, when the bog surface is not frozen.  During  the
unfrozen period, the upper surface of the decaying peat, approximately
20 cm, and the growing cover species act as a physical, chemical, and
biological filter for the effluent.  Physically, suspended solids are
filtered out, chemically, the high cation exchange rate of the peat
"holds" many of the inorganic nutrients,  and biologically, micro-organisms,
as well as the vegetative species, take up some of the nutrients of  the
effluent water as it passes through this living filter.  Since this  type
of wetland is generally nutrient-poor,  the addition of nutrient-laden
water should act to stimulate vegetative growth within the wetland.
This will be discussed in the next section.

     The hydrology of the bog will also be altered by the application
of the effluent.  The effluent discharges are made from the secondary
pond onto the bog surface through the use of 215 meters of gated
irrigation pipe.  The gates on the pipe are adjusted so even
dispersal of the effluent, across the bog surface, is accomplished.
The designed daily discharge is 100,000 gallons.  The application
takes place over a three to four hour period, early in the morning,
to take advantage of peak evapo-transpiration rates during mid-day.
On the day of a discharge, local and regional weather forecasts  are
followed to ascertain if any heavy rainfall  (>2.5 cm) will occur in
the next 24 hours.  If the weather looks good, the outflow weir is
checked to note the present discharge.   Based upon the pretreatment
water budget, if the outflow discharge is less than .06 cfs a
discharge can be made every day.  If the outflow rate is higher,
.06 to .12 cfs, discharge can be every other day, or if the discharge
is above .12 cfs, no discharge is made.  The discussion of how
these rates were determined if found in the next section.
                                      85

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                      DRUMMOND
           TERTIARY  SEWAGE TREATMENT
              DEMONSTRATION   PROJECT
Original Proposed
   Outfpll
                                Constructed Outfall
                               Outflow
 LAKE
DRUMMOND.

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Research Projects

     The research effort, at the treatment bog,  encompasses four
major areas; a water-quality study, a vegetative study,  a small
animal study, and a water and nutrient budget study.   The following
section summarizes each study and the status of  the work to date.
Most sutdies, except the small animal study, have at least one year
of pretreatment data.  Discharges to the bog began in May 1979, and
most of this year's data has yet to be analyzed  against  pretreatment
data, but in recent discussions with most researchers, nothing
unexpected has occurred, yet.

     An annual research meeting is held each spring at UW-Stevens
Point where the past year's data is summarized and the next year's
plans are discussed.  These meetings are open to anyone  interested in
the project.  An active mailing list is maintained by the Forest
Service; biannual updates on the project are prepared and an active
interchange of ideas is always encouraged.

Water Quality

               Dr. Bryon Shaw, Dave Mechenich
               University of Wisconsin-Stevens Point
               Stevens Point, Wisconsin  54481

               Funding - Upper Great Lakes Regional Commission

     This study consists of sampling water quality from the lagoon
system, through the treatment bog and downstream into the Weso Lake
system.  In the bog, 15 clusters of wells, consisting of a combination
of surface, near-surface (0.5m) and deep wells (3.0 m) are used to
sample water quality as the effluent moves through the bog system.
Samples are taken on a bimonthly basis during treatment  and monthly
otherwise.  Samples are analyzed for temperature, pH, conductivity,
alkalinity, total and calcium hardness, chlorides, D.O., COD, BOD^,
BOD20, ortho and total phosphorus, NH, , NO,,-, Kjeldahl N, and fecal
colirorins.

     Pretreatment data has shown that each well cluster reacts inde-
pendently of any other.  Therefore, analysis of changes in water
quality, as effluent moves through the bog, will have to be made on
a spatial and temporal basis, rather than the surface wells reacting
as a surficial unit.

     Based upon analyses through August 11, 1979, there has been no
change in water quality leaving the treatment bog.  Analyses of lagoon
water versus surface wells in the bog display a substantial reduction
in phosphorus and nitrogen to within "normal" pretreatment ranges at
respective well sites throughout the bog.  Chlorides, which are being
used as a trace of effluent movement within the bog have shown an
increase in the wells near the pipeline and along an unsuspected flow
path toward the outlet weir.  This will be studied further to determine
whether the pipeline should be moved to another location in the bog.
No changes  in water quality have been observed in the near-surface and
deep wells  due to the lack of water movement in these zones.
                                      87

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 Vegetative Study

           Dr.  Forest Stearns,  Dr.  Glenn  Gutenspergen
           University of  Wisconsin  - Milwaukee
           Milwaukee, Wisconsin  53201

           Funding - U.S.  Forest  Service

           Dr.  Dean Knighton, Dr. Sandy Verry, Dr. Dale Nichols
           North  Central  Forest Experiment Station
           Grand  Rapids,  Minnesota  55744

           Funding - U.S.  Forest  Service

           Dr.  Douglas Wikum, Dr. Martin Ondrus
           University of Wisconsin  - Stout
           Menomonie, Wisconsin  54751

           Funding - University,  Forest Service

     The vegetative study is composed of two parts: productivity and
 nutrient uptake  capabilities of  the predominate species of the bog,
 UW-Milwaukee and  Stout, and the vegetative composition of the bog,
 North Central  Experiment  Station.  The nutrient uptake study encompasses
 four permanent plots within the bog as well as selected individual
 trees and  a small number  of destructive plots in which present year
 growth vegetative  samples are  taken for nutrient analysis.  Pretreatment
 data has shown that  the nutrient quality of various species fall within
 published  data for  those  respective species, in their natural state.
 Other vegetative  studies  are also  taking place in the bog lagg zone
 (perimeter) and downstream in  the Weso Lake wetland.

     Data  during  this year's application period have yet to be analyzed
 but will be ready for the spring research review at UW-Stevens Point.

     The bog species composition study is being accomplished through
 aerial and bog level stereo photography.   The bog level photo points
 are both within and outside the permanent plots.  These pictures are
 evaluated with the data collected within the permanent plots and
 projected  over the entire bog.

 Small Animal Study

          Dr. Ray Anderson, Dennis Kent
          University of Wisconsin-Stevens Point
           Steven Point, Wisconsin  54881

          Funding - U.S.  Fish and Wildlife Service

     The fauna study began in the sping of 1979.   This study is
 designed to observe populations of  small  mammals,  birds,  amphibians,
and invertebrates within the bog system and  in the upland areas
 surrounding the bog.  The study will note how changes  in  the hydrology
of the bog as well as any vegetation changes affect  the movements,
 composition, and numbers  of species that  use the wetland.
                              88

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     The only point of interest so far in this study is the use of
the various research boardwalks by many of the small animals.   These
boardwalks were built to protect the fragile bog surface and aid the
researchers in collecting their data.  They have also changed some
faunal usage patterns by making movement much easier on these mini
highways versus the pre-existing animal trails.

Water and Nutrient Budget Study

          Hydrologist
          Chequamegon National Forest
          Park Falls, Wisconsin  54552

     The water budget is rather simplified since the bog is "perched"
above the regional ground water system.  The typical annual budget is:

       Precipitation - Evapotranspiration - Outflow = Storage

During the discharge period, mid April through October, assuming no
effluent discharge, and assuming an average daily discharge of 0.03
cfs* the budget is:

       Precipitation - Evapotranspiration - Outflow = Storage
       25.9 (inches) - 20.2 (inches) - 5.8 (inches) = -.1 inch

Assuming an effluent discharge to the bog equivalent to 3/4 design
capacity (11 million gallons of effluent) during this same period and
an average discharge of 0.12 cfs** the budget would be:

       Precipitation + Effluent - Evapotranspiration - Outflow = Storage
       25.9 (in.) - 18.3 (in.) - 20.2  (in.) -23.2  (in.) = 0.8 inches

     As can be seen from this crude budget, the additional effluent
water could be added to the bog and would cause a doubling of flow
leaving the bog.  The critical point here is timing the effluent
discharge to the timing of flows leaving the bog; the longer the
"contact time" for the effluent in the bog, the better the treatment.
As explained earlier these discharges of effluent to the bog are made
dependent on weather conditions and flow leaving the bog.  Discharges
are also planned to coincide with peak evapotranspiration rates.
Therefore, a bulk of the discharges occur between June and September
and each discharge is planned for early in the morning.
*   1/2 the average daily discharge during the period April-October 1978,

**  Twice the average daily discharge during the period April-October 1978,
                                       89

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     During the months of May, June, and July of 1979, approximately
2.8 million gallons of effluent have been applied.  The weather has
been extremely wet and has reduced the number of planned discharges.
An evaluation of this year's discharge record will be made to possibly
redesign next year's "operations manual."  Also, the results of a
related nutrient uptake study at the North Central Forest Experiment
Station has suggested that a greater number of discharges should occur
earlier in the year when the nutrient uptake capabilities of the plants
are greater.  This alteration in the effluent discharge pattern will
be discussed at the next joint research meeting.

     The nutrient budget is a joint project for members of the study
team.  Since the data must be pooled from various sources the first
budget will be prepared for the Spring 1980 meeting.

Conclusion

     The Drummond Project is a multi-resource study of a spaghnum bog
and its response to the application of sewage effluent.  The intent of
the project is to understand the dynamics of this type of wetland as
well as determining whether this type of wetland can be used to
effectively treat and assimilate residential sewage effluent.  Up to
this time, little was known of the dynamics or treatment capabilities
of spaghnum peat wetland.   This study will hopefully answer, in a few
short years, the capabilities of this type of wetland, as well as
adding to our general knowledge of the peat bog ecosystem.

     If further information is desired on any part of this study,
contact the principle researcher or the Forest Hydrologist,  Chequamegon
National Forest, Park Falls, Wisconsin  54552.
                              90

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     EFFECTIVENESS OF A WETLAND IN EASTER MASSACHUSETTS
     IN IMPROVEMENT OF MUNICIPAL WASTEWATER

     Donald A. Yonika, IEP, Inc., 534 Boston Post Road, P.O.  Box 438,
       Wayland, Massachusetts  01778
          The Town of Concord, Massachusetts Sewage Treatment Plant
currently discharges secondary level wastewater to a 48 acre deep marsh
which is part of the Great Meadows National Wildlife Refuge.  The
effectiveness of this wetland in further renovating effluent quality
was assessed as part of an 18 month feasiblity study on the use of
wetlands in the Commonwealth for advanced stages of wastewater treatment.
This research was conducted by IEP, Inc. for the Massachusetts Division
of Water Pollution Control.

     The Treatment Plant serves 6,000 of the total town population of
18,000.  Of the area serviced, roughly 80 percent of the design flow of
1 MGD is derived from residential uses and the remaining 20 percent from
light commercial, institutional and industrial use.  During the actual
study period inflow to the plant average .98 MGD.  Outflow as measured
by flow over the chlorine contact chamber weir, averaged .61 MGD.

     The Plant presently provides an acceptable level of secondary
treatment with 83 percent suspended solids and 90 percent BOD removal.
The system basically consists of an Imhoff Tank and outdoor sand filter
beds underdrained to the chlorine contact chamber.  Each of -the nine
three quarter acre filter beds is periodically closed for a 24 hour
period and rested for eight days.  Solids remaining on the surface are
removed and disposed of.  Chlorinated secondary effluent is discharged
directly to the wetland surface of a 48 acre deep marsh that is owned
by the Fish and Wildlife Service.

     The wetland functions as two units.  Just below the outfall is an
approximately 6 acre section of wetland that can be described as a
combination of both shallow marsh and shrub swamp.  Vegetation is
extremely dense, and almost impenetrable on foot.  The effluent travels
in no distinct channel, but flows through the vegetative mat, maximizing
contact between the wastewater and wetland soils and plants.  After
seeping through the 6 acre section, the wetland broadens out into a deep
marsh, with considerably more open water.  Retention time during the
study period was calculated to be about 57 days.  Water fluctuations
within the 48 acre wetland were only slight.during the growing season,
varying no more than two-tenths of a foot.  During the winter and spring
however, fluctuations were much more severe, varying by more than two
feet over normal water elevation.
                                       91

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     During the life of the study, the average concentrations of
wastewaters discharging to the wetland were 8.0 mg/1 ammonia nitrogen,
3.1 mg/1 nitrate nitrogen, .019 mg/1 nitrite nitrogen, 10.0 mg/1 total
kjeldahl nitrogen, 2.1 mg/1 total phosphorus, 1.6 mg/1 ortho phosphorus
and 38.2 mg/1 for BOD.

     A water sampling program was devised to attempt to quantify the
change in both concentration and loading between the secondary outfall
and the discharge point from the wetland to the Concord River.  Five
sampling stations were established, as indicated on Figure 1, entitled
Water Quality Sampling Station Locations.  Station 1 is the Treatment
Plant outfall.  Station 2 is located at the periphery of the 6 acre
shallow marsh - shrub swamp section.  Station 3 is located at the
drop-inlet discharge point from the wetland to the Concord River.
Stations 4 and 5 are located on the mainstream of the River, with
Station 4 upstream, and 5, just downstream of the Station 3 outfall in
a location where complete mixing of mainstream and wetland waters has
occurred.

     Nine rounds of sampling were accomplished during the study period.
Table 1 below presents the average concentrations for selected para-
meters tested at each station.

               Table 1  Water Quality Sampling Results

               Ammonia Nitrogen         Station mg/1
                                           1
                                           2
                                           3
                                           4
                                           5
         8.0
         5.4
         1.8
          .15
          .15
               Nitrate Nitrogen
Station mg/1
                                           1
                                           2
                                           3
                                           4
                                           5
         3.1
         1.3
         1.0
          .67
          .47
               Nitrite Nitrogen
Station mg/1
                                           1
                                           2
                                           3
                                           4
                                           5
          .019
          .070
          .040
          .010
          .010
                              92

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                             o
                             -fl
                             /•'
                             Treatment
                             Plant
                Water Quality

                Sampling Stations Locations
                                                        FIGURE 1
A FEASIBILITY STUDY:


WETLAND DISPOSAL OF WASTEWATER TREATMENT  PLANT  EFFLUENT

CLIENT: MASSACHUSETTS DIVISION OF WATER POLLUTION CONTROL     CONTRACTOR: IER INC. WAYLAND, MASSACHUSETTS

                                93

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          Total Kjeldahl Nitrogen
     Station mg/1
                                           1
                                           2
                                           3
                                           4
                                           5
             10.0
              7.2
              3.4
               .75
               .77
          Total Phosphorus
     Station mg/1
                                           1
                                           2
                                           3
                                           4
                                           5
              2.1
                .97
                .50
                .16
                .17
          Ortho Phosphorus
     Station mg/1
                                           1
                                           2
                                           3
                                           4
                                           5
              1.6
               .67
               .38
               .11
               .10
          Biological Oxygen Demand
     Station mg/1
                                           1
                                           2
                                           3
                                           4
                                           5
             38.2
              8.5
              5.8
              2.2
              2.3
     As can be readily seen, as the effluent travels through the
wetland, the concentrations of each parameter are considerably
diminished (with the exception of nitrite nitrogen).

     In order to remove the influence of dilution on the results,  a
loading analysis was conducted for each Sampling Station for the
parameters listed in Table 1.

     Table 2 summarizes the data in terms of total pounds per day
load for each of the selected  parameters at each Station during
the study period.

               Table 2 Results of Loading Analysis
          Ammonia Nitrogen
Station Loading, Pounds Per Day
       1               40
       2               39
       3               17
       4              322
       5              340
                              94

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          Nitrate Nitrogen         Station Loading, Pounds Per Day

                                         1               13.0
                                         2                9.9
                                         3               10.4
                                         4              982
                                         5              784

          Nitrite Nitrogen         Station Loading, Pounds Per Day

                                         1                  .10
                                         2                  .54
                                         3                  .39
                                         4               17.4
                                         5               16.6

          Total Kjeldahl Nitrogen  Station Loading, Pounds Per Day

                                         1               49.8
                                         2               52.4
                                         3               32.5
                                         4              1366
                                         5              1448

          Total Phosphorus         Station Loading, Pounds Per Day

                                         1                9.34
                                         2                7.51
                                         3                4.94
                                         4              240
                                         5              253

          Ortho Phosphorus         Station Loading. Pounds Per Day

                                         1                7.2
                                         2                4.6
                                         3                3.7
                                         4              166
                                         5              171

          Biological Oxygen Demand Station Loading, Pounds Per Day

                                         1              188
                                         2               63
                                         3               62
                                         4              3841
                                         5              4547

     Redacting further the calculations noted  above,  Table 3 presents
the average annual removal efficiencies of the 48  acre wetland for
the selected parameters.
                                          95

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                                Table 3

                  Average Annual Removal Efficiencies
                     For The Great Meadows Wetland

                Ammonia Nitrogen                   58%
                Nitrate Nitrogen                   20%
                Nitrite Nitrogen                 (292%)
                Total Kjeldahl  Nitrogen            35%
                Total Phosphorus                   47%
                Ortho Phosphorus                   49%
                Biological Oxygen Demand           67%

                (   )   Indicates Release

      The loading  data were further manipulated  to  see whether there
 were any seasonal variations in removal efficiencies.  The several
 rounds  of sampling results were grouped according  to growing season
 applicable to  the Great Meadows area,  from early spring to early,
 mid  and late growing season, to fall and early  winter, and finally
 to mid-winter.  The  data were  plotted  by season, and expressed as
 either  removal  or release rate.   Figure 2  is an example of the type
 of seasonal variation commonly reflected by most of the tested
 parameters.  The  results,  for  nitrate  nitrogen  show high removal
 efficiencies during  the growing season,  and a rapid release of this
 member  of the nitrogen series  as  the plants were killed back by
 frost action in the  fall.   This seasonal removal efficiency may be
 of significant  interest to  water  quality managers  trying to reduce
 in-stream concentrations of eutrophying nutrients  during the high-use
 summer  recreational  season, or  when stream low  flow may be a problem.

     Removal efficiencies were  calculated  not only for the various
 seasons,  but also  for  the  two different  wetland subtypes found within
 the  Great Meadows  Refuge.   This data is  also portrayed on Figure 2
 for  nitrate nitrogen.   Station  1  to 2  analysis  indicates function of
 the  6 acre  shrub  swamp  section.   Station 1 to 3 analysis portrays the
 function  of the overall  48  acre predominantly deep marsh wetland
 relative  to seasonal  removal or release  rates.

     Of the considerable more interest  to wastewater design engineers
 is data on absolute removal amounts.  Figures 3 and 4 are included as
 examples of the results  obtained  for ortho phosphorus and BOD,
 respectively, relative  to pounds  of each removed per day per acre of
wetland.  Closer inspection of either graphic indicates a significant
 seasonal variation in the amount  removed per acre of wetland as  well
as considerable difference betwen wetland subtypes.

     The mean annual uptake rate  for BOD for the deep marsh section
of the wetland is  2.6 pounds per acre per day.  The amount removed
by the shrub swamp - shallow marsh 6 acre section immediately adjacent
 to the Sewage Treatment Plant outfall is much higher - 20.8 pounds
per acre per day.
                              96

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                     100
                                                  89.6
                                                                              Sta. 4 to Sta. 5
                                                                                     Sta. 2
                               Early
                               Spring
                2
                Early
                Growing
                Season
3
Mid
Growing
Season
4
Late
Growing
Season
5
Fall and
Early
Winter
Mid
Winter
Removal Efficiency for Nitrate Nitrogen, Loading
 A FEASIBILITY STUDY:
 WETLAND  DISPOSAL
                                                                      FIGURE  2

                                               Yearly Removal      fta-1to fta-*  24%
                                                       Efficiencies- sta- 2 to sta- 3  <5 /0
                                                       cniciencies. sta 1 to S(a 3  2o%
                                                                 Sta. 4 to Sta. 5  20%
OF WASTEWATER  TREATMENT  PLANT  EFFLUENT
 CLIENT: MASSACHUSETTS DIVISION OF WATER POLLUTION CONTROL
                       CONTRACTOR: IEP, INC. WAYLAND, MASSACHUSETTS

-------
Pounds
per
per
20—-
UPTAKE .10^

—
.10-
RELEASE 2Q





A
Condition



B
1.20 —
1.10-
1.00-
.90-
.80-
UPTAKE
.70-
.60-
.50-
.40-
.30-

.20-
.10-

.10
RELEASE
.20-1

















Acre
Day
0.20 019




0.04 0.03 0.05
.„ ™™™ „,,,„, -07 Mean
'. 	 r...... -m iM.M.'.w.M.H.i.w......!...i.!i mmmsmm I i«*-,i —
Rate
per

	 	 A^^^j-k/v^
_ . _ ^cre/OMf
0.15 of DfkAv*
Marsh
123456
Early Mid Late Fall &
Early Growing Growing Growing Early Mid
Spring Season Season Season Winter Winter
1.2








0.41




























0.62


, 	 , 0.43 Mean
0.32 Uptake
Hate
per
Acre/Day
Swamp
	 ^^


1 o
.18
A - Ortho Phosphorus
Uptake & Release Rates
Stations 1 to 3
                        FIGURE
B - Ortho Phosphorus
Uptake & Release Rates
Stations 1 to 2
A FEASIBILITY STUDY:

WETLAND  DISPOSAL OF  WASTEWATER TREATMENT  PLANT  EFFLUENT
CLIENT: MASSACHUSETTS DIVISION OF WATER POLLUTION CONTROL     CONTRACTOR: IEP. INC. WAYLAND, MASSACHUsA-L.

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Pounds
per Acre
per Day
15-
10-
UPTAKE c
D —
n
RELEASE
O —


27 , 4

6

K3ffi 	

5

_ J-^.v-.v..............:.: • • • 	 ^JplOKG
•4 2 Rate
A per
Acre/Day
Condition 1 2 3 4 5 6 of Deep
Early Mid Late Fall & MarSh
Early Growing Growing Growing Early Mid
Spring Season Season Season Winter Winter
B
40 -,
35-
30-
25-
UPTAKE
20
15 -

10-

5-
0-
5-
RELEASE
10—1
38 yj









2.8
B'ivHi'Tw:-MvMvT'HvTJiii
lnn»d „, tai
33














	 - ^U.o Mean
Uptake
Rate
10 per
	 Acre/Day
of Shrub
Swamp

1


A-BOD
Uptake & Release Rates
Stations 1 to 3
                             B - BOD                 FIGURE 4
                             Uptake & Release Rates
                             Stations 1 to 2
A FEASIBILITY STUDY:

WETLAND  DISPOSAL  OF WASTEWATER TREATMENT PLANT
CUENT: MASSACHUSETT                                  '
CUENT: MASSACHUSETTS O-VS-ON OP WATER POCLUT.ON CONTROL

                                99
                                       CONTRACTOR: ER

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     The  same variable patterns hold for the nitrogen and phosphorus
 series.   The shrub swamp portion of the wetland removed, on the
 average,  .43 pounds per acre per day of ortho phosphorus, and .30
 pounds of  total phosphorus.  The deep marsh section was considerably
 less efficient, with values of only .07 and .09 pounds per acre per
 day for ortho and total phosphorus, respectively.

     Ammonia nitrogen at the rate of .17 pounds per acre per day was
 removed by the shrub swamp section: the entire deep marsh averaged .48
 pounds per acre per day.  Nitrate nitrogen removal comparisons were
 just the  opposite for the same wetland subtypes with .50 pounds per
 acre per  day removed by the shrub swamp, and .06 pounds per acre per
 day for the deep marsh.

     These figures agree well with the majority of investigations that
 have been  conducted throughout the north central and north eastern
 sections of the country, albeit the number of studies very limited.
 Generally, however, removal rates for phosphorus and the nitrogen
 series are low, in the range of one half pound per acre per day for
 these nutrients, which computes to a population equivalent of only 10
 to 50 people per acre of wetland, depending on whether nitrogen or
 phosphorus is of concern.

     Of notable exception to our study and the majority of the others
 are the results obtained by Dr. Maxwell Small in New York.  The
 absolute removal rates recorded by far exceed those obtained during
 this study.

     Overall, our results indicate that use of wetlands for secondary
wastewater polishing may not be economically feasible in states where
 larger wetlands are scarce near population centers, or where wetland
acquisition costs are high.

     Thus, a need exists to identify those characteristics or components
of wetlands which, in combination, would significantly increase the
efficiency (seasonal and year-round) of wetlands to renovate secondary
waste.   Construction of artificial wetlands or identification of
natural wetlands with components selected for maximizing renovating
efficiency, and matched to the particular secondary waste charac-
teristics of the plant,  may make the concept of wetlands for waste-
water renovation more viable in other than rural areas.
                              100

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WETLAND TERTIARY TREATMENT
AT HOUGHTON LAKE, MICHIGAN

Robert H. Kadlec, Department of Chemical Engineering
University of Michigan, Ann Arbor, MI  48109
     For five cosecutive summers, secondary wastewater was
discharged to areas within a peatland in central Michigan.
All nitrogen and phosphorus were removed from 100,000 gallons
per day within a five acre area.  The maximum water depth
increases were 10-15 cm, at the center of the discharges.
Some dissolved species, such as chloride flowed through the
treatment area with very little change; others such as pH
dropped rapidly to background levels.  No soil erosion or
plant mortality occurred.  Suspended solids deposited close
to the discharge.  Odor problems were slight.  No net virus
or coliforms were transported to the wetland.  Animal
populations have not yet responded to the discharge.
                                101

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 FLOOD  IRRIGATION  SYSTEMS

     The  Houghton Lake  sewage  treatment  plant  serves  a
 community of population 6-8,000,  which varies  seasonally
 for  this  central  Michigan  resort  location.   The  developed
 area is a strip bordering  Houghton  Lake.  The  septic  fields
 of the 1960's discharged into  this  shallow water body,
 leading to excessive  eutrophication,  and leading to the
 construction of a collection system and  a centralized
 treatment facility.   This  treatment plant went on stream
 in late 1974.
     The  treatment facility consists  of  two  aeration  ponds
 in series.  Sludge settles to  the bottom of  these ponds,
 and  wastewater overflows to a  29  acre holding  pond.   The
 original  design calls for  the  water to be pumped from the
 holding pond to seepage beds;  or, after  chlorination, to
 be spray  irrigated onto rye fields.   The capacity of  the
 holding pond is sufficient for nine months storage, thus
 permitting summer disposal of  the treated wastewater.
 Details of this system  are shown  in Figure 1.
     This research project tested a third alternative for
 disposal  of the treated water  from  the holding pond:  flood
 irrigation onto a State-owned  peatland.   A pilot transfer
 system was constructed, in June 1975, capable  of pumping
 100,000 gallons per day to the peatland.  This system
 consisted of:
 (1)  a buried, drainable force  main  from  holding  pond  to
     marsh edge;
 (2)  a buffer storage  pond  at marsh  edge  (for storage  and
     de-chlorination);
 (3)  an irrigation pump  station at marsh  edge.
 From the  buffer storage pond,  the water  was  distributed
 over the  northeastern end  of the  marsh,  using  1700 feet
 of 3-inch agricultural  irrigation pipe,  laid on  the
 surface.
     Two  study sites  were  developed:  one for  a  linear
 trickle discharge  (Site A)  and one  for a  single  point
 discharge (Site B).   Details are  shown in Figure  2.   During
 the period July 24  -  September 15,  1975,  2.12  million
 gallons of wastewater were pumped to  site A, at  the average
 daily rate of 40,000  gpd.   Nozzles were  located  every 30
 feet, for a total  of  22 holes.  These were sized  to give
 approximately the  same  flow from  each hole.   During the
 period May 25 - September  26,  1976  a  total of  10.26 million
 gallons of treated  effluent was pumped to the wetland and
distributed via the same 3 inch gated surface  irrigation
pipe.  The average  pumping rate was 360 m3/day (95,000 gal/
day).  On an average mound area of  65,000 m2 (16  acres),
this amounts to 3.9 cm/week,  or 70 cm during the  entire
 summer.  The only pumping problem encountered was intake
 clogging by algal debris at the sewage plant holding pond.
All gates in the peatland pipe remained open, even the
 smallest holes.
                         102

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o
00
           Houghton Lake
             Community
                V
            Collection
              System
Aeration
  Pond
Seepage
 Area
Aeration
  Pond
                                                          Cl,
                                                        Removal
                                             Upland
                                          Irrigation
                                            Fields
Holding
  Pond
                                                                                          Cl.
                     Figure 1.  The Houghton Lake treatment system.

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Peatland
ED
EH
                                                         Treatment
                                                          Plant
                                                                       O
              Figure  2.   Flood i.rriqation system.

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Figure  3.    Aerial photographs of the wetland wastewater
             treatment system at Houghton Lake, Michigan.

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o
en
                                                                                                        Figure   4.
                                                                                                     I'ORTLR RANCH  PCATLAND
                                                                                               Thiti nap at the wetland area was drawn flow
                                                                                               aerial photographs, showing major vegetation
                                                                                               types, the ua&tuuater discharge line fron the
                                                                                               Haughton Lake Sewer Authority, and the local ion
                                                                                               of sauipllng atationa.
                                                                                                                                                                 I-S5

Jcli't
kuud

EM.
•— •— . ^L
/^



i "
(
\
^
"\ '
i
1
\ A
                                                                              Surface  utoip 11 »|; vivll

                                                                           O K-tp well - 3S It.

                                                                            A  SiuplliiK lucailoiifc lor
                                                                              In unJ out (low*
13

-------
     During the summer of 1977, 6.21 million gallons of
secondarily treated sewage was pumped into the marsh during
two periods of 44 and 23 days  (June 3 - July 22; August 11
- September 3).  This severe loading test was conducted to
observe the effects on the peat soil and plant communities.
92,000 gpd was applied using a point discharge in site B.
     An approximately flat area in the sedge meadow was
chosen for Site B.  A pipe support and walkway was con-
structed of untreated pine 2" x 4" in a ladder-like
fashion.  The walkway supported the 3" aluminum pipe above
the peat soil and served as a working platform.  The walk-
way protected the marsh from becoming channeled, since
previous experience showed that walking trails left visible
scars and produced a preferential path for water flow.  The
walkway was 50 m in length and terminated about 5 m from
the discharge point.
     During the winter of 1977-78, a large scale flood
irrigation facility was constructed.  A small dechlorina-
tion pond was added at the treatment plant, together with
a 1700 gpm transfer pump.  Treated wastewater from the
dechlorination pond is pumped through a 12" diameter under-
ground force line to the edge of the Porter Ranch peatland.
There the transfer line surfaces and runs along a raised
platform for a distance of about 2500 feet to the discharge
area out in the wetland.  The wastewater flowing in the
transfer line is split between two halves of the discharge
pipe which runs 1600 feet in each direction.  Figure 3 is
two aerial photographs, of the treatment plant, and of the
transfer and discharge pipes looking down the Porter Ranch
wetland (toward the east).  The water is distributed evenly
across the width of the peatland through small gated open-
ings in the discharge pipe.  Each of the 100 gates dis-
charges approximately 16 gallons per minute, under typical
conditions, and the water spreads slowly over the peatland.
Figure 4 shows the location and overall layout of the
wastewater disposal system.
     The wetland treatment system was designed by Williams
and Works, Inc., based upon research results obtained at
the University of Michigan over the five years 1972-77.
This facility has been operated by the Houghton Lake Sewer
Authority  (HLSA) during the summers of 1978 and 1979.  Over
60 million gallons of secondarily treated wastewater were
transferred to the peatland in 1978, and over 100 million
gallons in 1979.  In addition  to continued research by the
University of Michigan, a small research program is
conducted by the HLSA, in addition to routine monitoring.
HYDROLOGY

     The Houghton Lake peatland is a perched wetland - a
peat bed of depth varying from 1-5 meters, underlain by a
thin, possibly intermittent sand layer  (10 cm), which rests
                                107

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                                             73 cm
o
oo
                 12 cm
               ± 2 cm
                                                clay
                                                                                     ± 2 cm
               Figure  5.  Approximate annual water budget  for  the  Houghton Lake peatland.

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o
CD
             -20
                     June
July
August
                                                                          September
                                                   Time
              Figure  6.  Water depth versus time at various distances  from irrigation

                          pipe, 1976.

-------
on  a  thick  clay  layer.  Thus, communication with deep
aquifers  is effectively blocked, and  the hydrological
process of  interest  involve surficial water storage and
movement.   Precipitation and evapotranspiration are the
transfers from and to the atmosphere; surface and shallow
subsurface  flows represent transfers  across the perimeter
of  the wetland.  Redistribution of the surface and sub-
surface water pool in the peatland occurs via overland
sheet flow,  and  soil suction mechanisms.  Figure 5 illus-
trates a typical annual water budget  for the entire wetland.
     Water  depths are typically in the 2-8 cm range, with
-35 cm to +35 cm being the range over 1972-77.  Surface
runoff water moves into the peatland  from the north and
east and leaves through the west and  south.  Much of the
water that  goes  through the peatland  is surface flow and
a heavy rain may temporarily raise water levels several
centimeters  on the peatland.  The water level is generally
highest in  the spring and lowest in the late summer.
Within any  one year  levels fluctuate  depending on rainfall.
     During  1975 and 1976, depths of  the water mound were
measured weekly at eight stations, and continuously at two
stations equipped with recorders in 1976; and some detailed
depth traverses were made.  Water depths for 1976 are shown
in Figure 6.
     The 1977 point discharge resulted in a roughly
circular mound of water of average depth 6-7 cm.  Flow
through this mound occurred radially, through approximately
1/3 of the  total available surface area.  The advance of a
front of rhodamine dye showed water spreading radially out-
ward from the point of discharge.  Although the dye did not
spread in perfectly concentric circles, there was a rela-
tively even distribution of water flowing outward from the
discharge point.  The length of the start-up transient was
on the order of 5-10 days, that of the shut-down was
shorter - on the order of 1-3 days.  Pumping established
a maximum center depth 6-8 cm greater than depths located
a long distance from the center of the ring.
     The full scale studies of 1978-79 show similar results.
The soil elevations in the discharge area are extremely
flat, with a gentle slope toward the Dead-Horse Dam outlet.
As a consequence, the addition of wastewater along the
3,200 feet of gated irrigation pipe gives rise to a mound
of water with high points along the discharge pipe.  Water
movement within the discharge area was evaluated by transect
measurements of water depth, flow rate and direction.
Sixteen float gages and four Stevens Recorders provided a
continuous record of water depth from the end of May through
October, 1978; 29 staff gages and four recorders were used
from March to September 1979.
     Table 1 gives approximate water depths on three tran-
sects within the discharge area in 1978.   It can be seen
that the water sheet thins in the downgradient direction,
and has variable depth as one proceeds toward the upgradient
                         110

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    Table 1.   Approximate Water Depths During Wastewater
              Discharge.  Transects on August 30, 1978.
Meters from
Discharge
Downgrade
0
+ 20
+ 50
+100
+200
+ 300
+400
+500
Leatherleaf v '
Transect

7
7
3
6
2




. 0 cm
. 0 cm
. 4 cm
. 3 cm
. 8 cm
-
-
-
Sedge-Willow v '
Transect

13.
10.
7.
8.
8.
5.
6.
5.

8
5
9
2
6
7
1
2

cm
cm
cm
cm
cm
cm
cm
cm
Cattail VJ'
Transect

7
18
28
30
29
6



.1
.3
.6
.0
.0
.3
-
-

cm
cm
cm
cm
cm
cm


Toward Shore
   - 20           6.7 cm
   - 50           9.3 cm
   -100           5.9 cm
   -200           3.6 cm
   -300

(1) Located near SW 11 on Figure 4.
(2) Located near SW 12 on Figure 4.
(3) Located near SW 13 on Figure 4.
 9.7 cm
11.8 cm
 9.8 cm
 9.0 cm
10.0 cm
 7.9 cm
 9.0 cm
17.4 cm
 5.8 cm
 4. 3 cm
                                   111

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18-
                                     Figure 7.




                      DYNAMIC RESPONSE OF WATER LEVEL TO IRRIGATION


                                     PORTER RANCH PEATLENT - 1978


                      TRACE FROM A STEVENS RECORDER LOCATED NEAR THE

                              TEE  IN THE DISTRIBUTION LINE,
CO
o:
LU
H
ui
h-
z
UJ
o
d.
LU
Q
   14-
   12-
   10
    8-
             PUMP  ON
                                      PUMP OFF
              8/10

             (8 A.M.)
                        8/11
8/12
8/13
                                          DATE
                             PUMP ON
8/14
8/15
I

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              50     100
           Distance, m
                         150
                                   60
                                  
-------
             50

           Distance  (m)
               ISO
  50     100

Distance (m)
150
  180
W
01
0)
c
T3
i-i
(0
S
W
                                 150 r-
             50     100

            Distance  (m)
                                 100 -
               150
                     50--,
  50     100

 Distance  (m)
150
Figure   9<
Surface water parameters within the treatment  area
averaged from June to August.  Samples were
collected weekly.
                            114

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shore.  The cattail transect was taken intentionally in one
of the isolated depressions within the wetland, leading to
the largest observed water depths at any point in the
irrigation area.
     Surface water velocities ranged from 20-60 cm/min for
the sedge-willow cover type on August 30.  These data are
subject to extreme variability, and reflect the fact that
only a small fraction of the peatland surface is available
for flow.  This information, when coupled with the depth
information, indicates a relatively uniform moving sheet
of water proceeding through a wide variety of channels and
clumps on its course downgradient through the peatland.
     The time response of water depth to the initiation of
or cessation of pumping is shown in Figure 7.  When the
pump was turned off on August 11, there was an immediate
decline in water levels near the pipeline, at approximately
3 cm per day.  When pumping commenced on August 14 there
was an immediate rise in water level to the old level
established by prior pumping, with the entire transient
occurring within the space of one day.  Thus, the transient
response of the deepest water area, at the irrigation pipe,
is very fast.  The transients at remoter locations are
considerably slower.
WATER QUALITY

     The shallow tea-colored waters of this peatland are
normally acidic, and laden with dissolved organic material.
The background pH is in the range of 5-7 during summer
months.  Conductivity is also low for the natural wetland,
with values in the vicinity of 280 ymho/cm.  With respect
to many water quality parameters, the wetland waters
contain relatively small amounts of dissolved material.
Typical background data for different depths and cover
types are given in Table 2.  Subsurface interstitial water
has a somewhat elevated nitrogen content compared to
surface waters.  There are also notable seasonal changes
in some dissolved materials.  All data display a rather
large variability, which appears to be characteristic of
this wetland.
     During the pilot scale treatment of effluent in 1975,
relatively clean water was discharged in late summer.
Concentrations of dissolved constituents in surface waters,
and 15 and 45 cm below ground, are shown in Table 3.  The
data show no influence of the effluent on nutrient concen-
trations in water samples at any distance from the pipeline.
     Typical 1976 patterns of surface water chemistry with
distance from the effluent discharge are shown in Figures 8
and 9.  Chloride concentrations were comparatively high
within the treatment site primarily as a result of the
effluent discharge.  Nitrate-nitrite-N was consistently
removed from the effluent within 30 m of the discharge
                                115

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   Table 2.  Dissolved Nutrient Status in Several Plant
             Communities.  Undisturbed Houghton Lake
             Peatland, 1973.   (mg/£) Means over depth
             and time.  Second number is standard
             deviation.
Approximate
No. of
Samples
NH -N
TOP
Ca
Mg
Na
Si0
Cl
              Leatherleaf-
               Bog Birch
               Sedge-
               Willow
          Mixed Deeper
          Water Areas
    230         115         90
  1.9±1.7     1.1±0.8     1.5±1.4
0.066±0.035 0.056±0.023 0.060±0.038
   0.066
   21±8
  4.0±1.6
  5.6±4.2
  1.411.2
   29±21
 0.077
 31112
5.9±2.3
6.4±5.0
1.3H.1
 27 + 21
 0.098
 40±26
7.4±4.2
5.2±4.3
2.0H.8
 20±21
             1972
             Rain
 70
0.29
0.45
0.040
                         116

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      Table  3.   Effluent and Wetland Water Quality on
                August 22,  1975 in the Wetland Waste-
                water Treatment Area.
Distance
from
source
(m)
NH4-N N03+N02~N




TOP

	 11
Cl
ig/8,
K

Na

Ca

Mg

Surface Samples
0
30
110
170
15 cm deep
0
30
110
170
45 cm deep
0
30
110
170
0
0
0
0

0
0
0

0
0
0
.70
.47
.23
.50
*
.52
.30
.42
*
.75
.21
.81
0
0
0
0

0
0
0

0
0
0
.9
.23
.05
.13
*
.20
.06
.18
*
.25
.11
.15
0
0
0
0

0
0
0

0
0
0
.33
.04
.03
.05
*
.04
.03
.04
*
.04
.08
.21
64
39
16
35
*
21
22
51
*
16
63
43
0.9
0.5
0.5
0.3
*
0.7
0.1
0.3
*
0.2
0.4
1.9
12
10
8
6
*
6
7
6
*
3
7
11
8
8
10
11
*
27
20
8
*
19
19
30
4
3
2
2
*
4
4
1
*
4
4
6
* Not sampled.
                                117

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 during the entire pumping  schedule.  NH4-N concentrations
 were  higher  at  some  stations  in the treatment area than in
 the effluent.   Concentrations of total dissolved P
 decreased sharply with distance through most of the
 discharge period, although TDP concentrations in samples
 30 m  from the pipeline tended to increase through the
 summer.
      Total alkalinity, hardness, and pH decreased rapidly
 with  distance from the discharge source, while COD
 increased.   The increase in COD was due to high concentra-
 tions of dissolved organic matter in wetland surface waters,
      Heavy metal  (Pb, Cu,  Ni and B) concentrations were
 below the detection  limits of our equipment.  June, July,
 and August samples from the effluent and several stations
 in the wetland  were  less than 1.0 mg/£ for Pb, 0.50 mg/£
 for Cu and Ni,  and .05 mg/£ for Zn.
      The 1977 sampling stations were established in 6 con-
 centric circles around the point discharge.  Nutrient
 removal was  effective with background concentrations being
 reached at 80 meters for TDP and at 30 meters for NO3~N.
 Nutrient mass balances for the point source irrigation were
 calculated using water chemistry and hydrologic information.
 Dissolved nitrogen storage within the first 40 meters was
 82%;  that for TDP was 67%.
      Suspendable solids varied erratically with distance
 from  the discharge.  Although it is difficult to accurately
 sample the marsh waters for the weight parameter, the color
 changes and  chemical changes exhibited by the suspendable
 solids with  distance were  obvious.   The water velocity is
 nearly inversely proportional to the square of the radius
 in this circular geometry, leading to a sedimentation
 profile which changes dramatically with radial distance.
 Solid material could be entrained close to the discharge,
 and redeposited later.  Some of these solids were clearly
 algae, as indicated by the green color of the sediments.
     The full scale  system was studied in similar detail in
 1978 and 1979.
     Transects were made throughout, and after the pumping
 season, which consisted of collection and analysis of water
 samples at regular intervals, beginning at the discharge
pipe and extending up to 500 meters in each direction.
Transects were made  in each of the three principal cover
types:  sedge-willow, leatherleaf and cattail.  Samples
were also taken at some sites at 15 cm and 45 cm depths.
Measurements of conductivity, pH,  dissolved oxygen and
redox potential were also made, in the field, co-incident
with the collection of transect samples.   Peat samples were
collected, and the interstitial water separated and
analysed.
     Water samples were typically analysed for pH, conduc-
 tivity, ammonium-N, nitrate-N, chloride,  total dissolved
phosphorus and various metallic cations.   Ammonium, nitrate
 and chloride levels were measured using specific ion
                          118

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     "§T>
                          Figure   10.

                   NITROGEN  (NHj.*) REMOVAL FROM WASTEWATER
                          PORTER RANCH PEATLAND
                       TRANSECTS ON 30 AUGUST 1978
                                                  CSVEH TYPgS

                                                 3 CATTAJL
                                                 O SEDSE-WILLOW
                                                 • LEATHERLEAF
                                               '-a
                         100                200
                          METERS DOWNGRADE FROM DISCHARGE
                                                               300
    2 -
                  Figure   11.
          PHOSPHORUS  REMOVAL FROM WASTEWATER
                PORTER RANCH PEATLAND
             TRANSECTS ON 30 AUGUST 1978
        «£<  •
0.
1=1
to
3
    1 -
    o -*i

              Q
                   **s-«.J.».«.
                                                           Types
                                                    B  CATTAIL
                                                    •  LEATHERLEAF
                                                    ®  SEDGE-WILLOW
                                           Typical
                                           Tcnae of dxta
                                                       v
                                                         ^>J=
                                  ©•
                                        •©••«
                              100                     200
                          METERS DOWNGRADE FROM DISCHARGE
                                                                          o-
                                            119

-------
            Figure  12.

               GROUND WATER pH
          PORTER RANCH PEATLAND
          TRANSECTS ON 30 AUGUST 1978
  =£  5  -
             COVER  TYPES
           a CATTAIL
           O SEDGE-WILLOW
           • LEATHERLEAF
                                100                    200

                             METERS DOWNGRADE FROM DISCHARGE
   800-
                   Figure  13.

                 GROUND WATER CONDUCTIVITY
                   PORTER RANCH PEATLAND
               TRANSECTS ON 30 AUGUST 1978
   600-
5  400-
          3 CATTAIL
          ® SEDGE-WILLOW
             LEATHERLEAF
                          —T"
                          100
—T-
 200
                         METERS DOWNGRADE FROM DISCHARGE
                                   120

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electrodes.  Total dissolved phosphorus (TOP) was deter-
mined using a colorimetric (ascorbic acid) technique, after
digestion of the filtered water sample by sulfuric acid and
ammonium persulfate.  Atomic absorption spectroscopy was
employed to determine concentrations of sodium, magnesium,
copper, iron and nickel in solution.  A comparison of
surface water and interstitial water nutrient status is
given in Table 4.
     Data from transects of the three cover types on August
30th are presented in Figures 10 through 13.  The declines
of dissolved nutrients are quite similar to those in the
pilot-scale experiments, except for the deep water cattail
cover type.  Comparable results have been obtained in 1979.
     Table 5 shows neutron activation analyses of discharge
and background water samples.  Within the scope of this
analysis, only sodium displayed elevated levels at the
discharge.  Atomic absorption analysis shows magnesium is
also higher in the discharge area.
SOILS

     The peat deposits in this wetland range from 0.5 to
3.0 meters thick.  They contain wood fragments, and occa-
sional deposits of sand and clay.  Chemical analyses of
Houghton muck, a histosol, reveals that the highest levels
of carbon and soluble phosphorus are found in the upper
layers of the profile.  Acidity and potassium in both cover
types decrease with depth.  Higher carbon but lower phos-
phorus and potassium levels are found in the leatherleaf-
bog birch cover type.  The chemical composition of the
Houghton muck closely follows the characteristics of
organic soils reported by many others.
     Table 6 compares the chemical composition of peat
samples at two distances from the 1976 effluent pilot
discharge.  Total P, Na, and Mg were significantly  (P < .05)
higher in peat samples from the 0-5 cm depth 3 m from the
discharge compared to 30 m.  Total N, K, and Ca were also
higher in peat samples from the 0-5 cm depth near the pipe-
line but the differences were not statistically significant,
     Soil samples were obtained in 1978 and 1979 along
transects perpendicular to the pipeline.  Each core was
divided into three segments  (0-5 cm, 5-10 cm, and 10-20 cm)
and analyzed for total N and P.  Table 7 shows no probable
increase in P or N within the surface horizon.
VEGETATION

     The vegetation  in  the peatland  is  typical  of  northern
peatland systems.  The  two dominant  cover  types, sedge-
willow  (Carex  spp. and  Salix  spp.) and  leatherleaf-bog birch
 (Chamaedaphne  calyculata  (L.) Moench. and  Betula pumila  L.),
                                121

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  Table 4.  Nutrient Analysis of Surface and  Interstitial
            Water from Top 10 cm of Litter and Peat Soil,
            Houghton Lake Wetland.  Sedge-Willow transect,
            30 August 1978.
Distance
from
Discharge
(m)
0
10
20
30
40
50
60
80
110
140
200
300
400
500
N-NH4
mg/£
Interstitial
35
16.8
24.0
32.4
24.3
16.8
15.5
14.8
12.1
9.4
14.2
13.1
9.8
12.1
Surface
3.8
3.1
2.6
2.8
2.6
1.0
0.94
0.35
0.21
0.09
0.07
0.12
0.18
0.09
Total Dissolved
Phosphorus
mg/S,
Interstitial
1.25
0.67
2.96
2.59
0.17
0.11
0.06
0.08
0.09
0.38
0.08
0.09
0.07
0.07
Surface
1.58
1.95
1.25
0.55
0.17
0.09
0.07
0.065
0.055
0.055
0.04
0.055
0.035
0.06
Note:  Soil samples stored frozen before removing inter-
       stitial water.
                            122

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  Table 5
Multi-element Analysis by Neutron Activation
Analysis.  Water Samples Taken August 29,
1978 in Porter Ranch Peatland.
Element
                 Wastewater
               Inflow at pipe
                             Background
                            Water Sample
                          (500 m downgrade)
                         	  mg/£	
  Sm
  Lu
  U
  Th
  Cd
  Au
  Ba
  Nd
  As
  Br
  Na
  La
  Ce
  Se
  Hg
  Cr
  Hf
  Ag
  Cs
  Ni
  Tb
  Sc
  Rb
  Fe
  Zn
  Ta
  Co
  Eu
  Sb
   < 0.0027
   < 0.0016
   < 0.0336
   < 0.0173
   < 0.2458
   < 0.0014
   < 3.5962
   < 0.5728
   < 0.0826
     0.2065±0.0112
    62.9354±2.0204
   < 0.0068
   < 0.0380
   < 0.0304
     0.0244 ±0.0033
   < 0.0456
   < 0.0030
   < 0.0154
   < 0.0039
   < 0.3409
   < 0.0021
   < 0.0004
   < 0.1399
     3.127810.6840
     0.2799±0.0394
   < 0.0031
     0.003410.0008
   < 0.0015
   < 0.0083
< 0.0027
< 0.0017
< 0.0328
< 0.0177
< 0.2533
< 0.0015
< 3.4246
< 0.6625
< 0.0747
  0.225310.0112
 26.1746+1.3751
  0.0348+0.0028
< 0.0366
< 0.0321
  0.033910.0034
< 0.0683
< 0.0033
< 0.0188
< 0.0054
< 0.5031
< 0.0034
  0.000610.0001
< 0.1573
< 3.0348
  6.960010.1249
< 0.0037
  0.006910.0009
< 0.0017
< 0.0039
                                  123

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 Table 6.  Total Element Concentrations in Peat Samples
           From the Sedge-Willow Cover Type at Distances
           From the Discharge Site.  Samples Were Collec-
           ted in Late June 1976.  Values in Parentheses
           are Standard Errors of the Mean.
Distance from
Effluent Source
and Depth of
Sample
3 m from Source
0-5 cm
5-10 cm
10-15 cm
30 m from Source
0-5 cm
5-10 cm
10-15 cm
N
%

2.55
(.08)*
2.85
(-17)
2.80
(.03)

2.32
(.09)
2.05
(.38)
2.39
(.19)
P
%

0.13
(.01)
0.11
(.007)
0. 08
(.006)

0.10
(-01)
0.08
(.01)
0.07
(.01)
K
%

0.10
(.005)
0.07
(.003)
0.06
(.003)

0.09
(.004)
0.08
(.01)
0.07
(.01)
Na
yg/g

210
(36)
80
(36)
48
(18)

100
(13)
10
(ID
8
(3)
Mg
%

0.17
(.01)
0.13
(.01)
0.12
(.007)

0.14
(.003)
0.13
(.01)
0.14
(.01)
Ca
%

1.30
(.06)
1.32
(.10)
1.66
(-05)

1.19
(.04)
1.12
(.19)
1.53
(.17)
* n=4
                         124

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 Table 7.   Nutrient Analyses of Soil Samples at Various
           Distances from the Wastewater Discharge, Full
           Scale Operation, Sedge-Willow Community. (% DW)
Phosphorus
Core Section, cm
0-5
1978 5-10
10-15
0-5
1979 5-10
10-15
15-20
Nitrogen
0-5
1978 5-10
10-20
0-5
1979 5-10
10-15
15-20
2.5
0.14
0.11
0.07
0.13
0.12
0.07
0.08

2.38
2.83
2.55
2.09
2.13
2.21
2.24
Distance, m
30
0.14
0. 12
0.08
0.13
0.11
0. 11
0.06

2.15
2.60
2.44
1.88
2.05
2.34
1.97
60
0.13
0.10
0.08
-
-
-
-

2.54
2.43
2.90
-
-
-
-
                                125

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 account  for about  88% of  the peatland.  Open water areas
 (5%)  provide the main habitats  for  a variety of aquatic
 plants such as  Potamogeton  spp. and Utricularia spp.
 Cattail  (Typha  latifolia  L.) stands are closely associated
 with  depressions in  the peatland and occupy 2% of the total
 area.  Alder  (Alnus  rugosa  (Duroi)  Spreng.) is found
 primarily around the edges  of the peatland and accounts for
 3% of the ground cover.   Aspen  (Populus tremuloides
 Michaux.), the  primary upland cover, is occasionally found
 in small  stands in the peatland and these patches make up
 2% of the total area.  Irrigation sites A and B were
 primarily in the sedge-willow community, but the full scale
 project  encompasses  all cover types.
      Data from  earlier research on  nutrient additions
 indicated potential  uptake  of phosphorus and nitrogen by
 the vegetative  communities, including  litter.  The vegeta-
 tion  in August  1975  was studied 30  m and 150 m from the
 pipeline and in a  control area  outside the experimental
 area.  The mass of live Carex spp.  both above and below
 ground was not  significantly different among sampling
 locations.  Furthermore,  although considerable variation
 existed, the concentration  of N, P, Ca, Mg, K, and Na was
 not significantly  higher  in samples of Carex spp. leaves,
 Carex spp. roots,  surface litter and standing dead plant
 material  from experimental  areas compared to control areas.
      The amounts of  total live, standing dead, and litter
 were  not significantly different (P < .05) among sample
 locations in 1976.   Foliar  N and P  concentrations of plant
 species near the discharge  area were higher near the pipe-
 line  compared to concentrations measured in 1973 and 1974.
 Nitrogen concentrations in  live, dead, or litter compart-
 ments were not  significantly different among sampling
 locations.  Phosphorus concentrations, however, were higher
 in litter and Carex  spp.  leaves nearer the pipeline than
 other areas.  P concentrations  in standing dead compart-
 ments did not appear to increase as did the live and litter
 compartments.
     While biomass measurements were not significantly
 different, cattail (Typha latifolia) dimensions were larger
 in the discharge area.  Cattail maximum height averaged
 170 ±25.6 cm (X ± s;  n = 60) within  6 m of the discharge
 area  compared to 145 ±24.2  cm approximately 50 m from the
 discharge.  Circumference of the shoot base was also
 significantly different with mean values of 13.3 ± 3.7 and
 9.4 ±  2.95 within 6 m and  50 m of the discharge area,
 respectively.
     An additional indication of the response of the vege-
tation to the wastewater  discharge was chlorophyll a con-
tent of sedge leaves.  Sedges near  (6  m)  the pipeline
appeared greener compared to sedges further away.   Chloro-
phyll a_ concentrations were 110 mg/g fresh weight of tissue
compared to 80 mg/g  fresh weight away  from the discharge
area.
                         126

-------
     In the full scale project, above ground standing crop
in the sedge community near the pipeline increased in
response to the nutrient additions.  Measurements taken in
1978 after cessation of effluent discharge showed that the
total above ground standing crop was approximately twice
as much at the pipeline than at stations 90 m from the
source of wastewater.  In 1979, increased standing crops
were prevalent out to and beyond 90 m.
     Dramatic changes in species composition have not
appeared in the early years of the discharge, but baseline
data has been taken for future reference.
     A zone of foliar N and P enhancement has developed,
extending to and beyond 90 meters from the pipeline.  The
mass of N and P in the above ground standing crop decreased
with distance in 1978, but not in 1979.  (Table 8.)
     Nitrogen and phosphorus in the litter were measured as
percent of dry weight.  The data in Table 9 shows increased
P near the discharge in 1978, but not increased N.  In
1979, the zone of increased P extended to and beyond 100 m.
ALGAE

     The response of the algal community of the Porter
Ranch Wetland to nutrient enrichment was studied by 3
methods during the summer of 1976.  Continuous flow bio-
assay chambers were designed and constructed to measure
in situ increases of Cladophora sp. dry weight and to
provide continuous monitoring for potential toxic dis-
charges.  Aquatic community metabolism was measured by the
examination of diurnal oxygen fluctuations.  Productivity
estimations for epiphytic algae were made by determination
of Chlorophyll a concentrations on artificial substrates
of known surface area.  This method was also used to
determine the effects of increasing water depth in epi-
phytic algal production.
     Nutrient uptake by the algal community was estimated
by calculation procedures based on measurements of nutrient
concentrations of the bioassay algae, coupled with bioassay
growth rate estimates.
     Growth rate of the bioassay algae at the pipeline
(nutrient enriched) study site was 2656 mg dry wt m~2 day"-*-
for the period between June 12, 1976 and July 3, 1976.
Growth rates in the control area were 85 mg dry wt m~2
day"1, for the same time.  The standing crop of Cladophora
at the enrichment site was 41 g dry wt m~2 on July 7, 1976.
On the same date, the standing crop of Cladophora at the
control site was 5 g dry wt m~2.
     Aquatic community productivity as measured by the
dissolved oxygen method were an average of 225% higher in
the discharge site, compared to the control site.
Dissolved oxygen values in excess of 250% saturation were
commonly recorded in the surface water of the discharge
                                127

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Table 8.  Standing Crop Biomass and Nutrient Status in the Sedge-Willow
          Community at Various Distances from the Discharge.   Ranges of
          Data Over Triplicates are Typically ±30%.


Distance
  2-5
  30

  60

  90
Biomass
o
gm DW/m
9-21-78
525
380
190
270
8-29-79
556
620
-
712
Nitrogen
gm/m
9-21-78
10.6
6.2
2.8
3.9
8-29-79
10.2
9.5
-
10.8
Phosphorus
2
gm/m
9-21-78
1.7
1.3
0.6
0.4
8-29-79
2.2
1.7
-
1.92

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                Table  9.   Nutrient Concentrations in Litter,  Sedge-Willow Community.
                          (%  DW)

                    Distance from              Nitrogen                  Phosphorus
                    Discharge, m           8/30/78   8/29/79           8/30/78   8/29/79
                           0                  1.73     2.10              0.22      0.26
                          30                  2.20     2.40              0.22      0.31
                          60                  1.87      -               0.10
                          80                  2.58      -               0.11
co                        100                   -        2.25               -       0.52
                         110                  2.38      -               0.11

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 site.   In the late  summer,  simultaneous dissolved oxygen
 consumption  in  full  sunlight, pH  values in  excess of  10.0
 and dissolved Q>2  supersaturation  strongly suggest that
 photorespiration  of  the  algal community plays an important
 part  in the  seasonal pattern of algal productivity under
 conditions of nutrient enrichment.
      There was  no significant difference in chlorophyll a
 concentrations  at study  sites in  the wetland.           ~
      Nutrient uptake rates  of the bioassay  algae were 12
 mg P  m~2 day"-*-  and  55 mg N  m~2 day"-'-.  End  of the growing
 season  values for total  nitrogen  and phosphorus content of
 the bioassay algae were  4.3 g N m~"2 and 0.96 g P m~2,
 respectively.
PATHOGENS

     A variety of surface water samples were analyzed  for
both total coliforms and fecal coliforms by the most
probable number method, both during the 1975 and 1976
irrigation seasons, and during 1974.  The 1974 sampling
program was intended to provide background data on
coliforms in the wetland, its inlets, outlets, and
neighboring receiving water bodies.  The results of this
work are given in Table 10.
     Coliform levels at all locations at all times dis-
played considerable variability.  The sewage plant aeration
ponds displayed the expected high levels, but the sewage
plant holding pond, from which wastewater was pumped,
showed fairly low levels during all pumping periods.  At
no time during the summers of 1975 through 1979 did the
pumped water exhibit more than the legally allowable 200
fecal coliforms per 100 ml of water.  This information
allowed the operator to refrain from chlorination during
all irrigation periods.
     The fecal coliform levels were considerably lower than
total coliform levels both during the background year of
1974 and during the pumping years of 1975 and 1976.  Within
the natural wetland, fecal levels ranged from 0 to 20% of
the total coliforms reported in Table 10.  Within the study
sites in 1975 and 1976, the percent fecal coliform ranged
from 0 to 50%.
     It is known that raw sewage contains human enteric
viruses,  and that sewage treatment plants reduce these con-
centrations.   In late summer 1977, a field test was under-
taken to determine the profile of virus concentrations at
various stages of wastewater treatment, and in the wetland
irrigation site.   Samples were collected and preconcen-
trated in Michigan,  and subsequently analyzed at the
University of New Hampshire under the direction of
Dr. Theodore G.  Metcalf.
     The results of these analyses are given in Table 11.
The recoveries of virus from the standards was not good,
                         130

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        Table 10.  Total Coliform Bacteria, Houghton Lake Wetland.
                   (MPN method) (Number per 100 ml) (Averages)
1974
1975
1976

4/21
5/28
7/14
8/9
8/27
9/30
i
5/17
7/4
8/15
6/4
7/1
7/12
7/27
8/24
Natural
Inflows
—
390
270
110
585
2765
140
270
140
_
1700
-
-
-
Natural
Outflows
—
264
435
120
170
6585
20
80
110
—
715
-
-
-
                             Interior Points
                                 (Control)
                                   1100
                                   7122
                                    452
                                     92
                                    563
                                   1960
                                     20
                                    140
                                     20
Discharge
Discharge
  Area
                                   2787
   none
   none
    53
    80
   710
   850
   965
40,000
   270
  3667
    25
   483
  7623
  1330
  1685
46,000
 Receiving
Water Bodies
                          250
                         1393
                          860
                         8070
                          640
                         3400
     25
    183
     83
   1700

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  Table 11.  Recovery and Identification of Virus Isolants
             from the Houghton Lake Sewage Treatment Plant,
             Pilot Irrigation Site B, and an undisturbed
             Wetland Site.  (50 gallon samples)
Sample
Aeration Pond
  #1
Aeration Pond
  #2

Holding Pond/
  Discharge

20 meters from
  Discharge

40 meters from
  Discharge

Wetland
  Background

Standard 1
  (2500 PFU)

Standard 2
  (2500 PFU)
Virus Isolant
 Recovered
Number Isolants
   Recovered
     (PFU)
                      1


                      1


                      0


                      0


                      0


                      0


                     14


                    142
 Isolant
Identity
                Echovirus 32


                Echovirus 32
                         132

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in that only 1.5% of the low concentration was recovered.
The estimated analytical recovery (New Hampshire)  was 25%,
leading to an estimated sampling recovery (Michigan)  of 6%
for the low concentration levels encountered.   This is not
surprising in view of the extreme difficulty of sample
collection and pre-processing in the wetland situation,
and the unavoidable delays in sample transport and storage
occasioned by the large distances between the site and the
laboratories.
     A study of the full scale site in fall 1978,  conducted
entirely within Michigan, yielded quite different  results.
Both reovirus and poliovirus were found at all locations
in the treatment plant and the wetland, with a hundred-fold
reduction occurring on passage through the treatment plant.
The wetland (control site) and the treated wastewater
exhibited the same total virus.  The surface water of the
wetland was experimentally determined to be hostile to
poliovirus, but not to reovirus.
VERTEBRATE AND INVERTEBRATE FAUNA

     Data on wetland wildlife populations from 1975-1977
consists of mist net caputres of birds, transect data for
herptiles and field obsQrvations for larger mammals.  There
were no dramatic changes in either species abundance or
species composition of wetland birds between the summers of
1973 and 1975.  In 1973  (background) mist netting resulted
in the capture of .54 birds per mist net hour.  In 1975
(pjlot project) mist netting yielded a capture rate of  .38
birds per mist net hour.  Species composition of the mist
net captures was similar during both years, with swamp
sparrows and yellow throats comprising 79% of the birds
caught in 1975 and 62% of the birds caught in 1973.
     During the pumping season of 1976, one new muskrat
lodge was established near the pilot area discharge site,
since this was the only standing water available.  After
pumping ceased, the lodge was abandoned.  White-tailed deer
were the only other mammals observed in the pilot area of
the marsh during 1975-77.  Deer sightings remained at
constant frequency during this period.
     In 1978, under the auspices of the HLSA, several
methods were used in the collection and enumeration of the
vertebrates and invertebrates of the marsh in the area of
discharge.  Selective dipnetting, in water zones, was used
to collect aquatic insects prior to pumping.  Wire mesh
cones located in front of the discharge pipe collected the
influx of invertebrates and fish from the treatment plant
holding ponds.  Core extractions were used to determine
zone effects of aquatic  insects and invertebrates.  Non-
aquatic insects were collected in sweepnet samples from
the various habitats in  the area of discharge.  Shading and
basking platforms were set up to provide observation sites
                                133

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 for  herps, minnow  traps were  useful  in entraping amphibians
 and  fish.  Small rodents were collected  in  live traps,
 larger mammals  by  observation only.
      This  research is  continuing  in  1979, with the goal of
 understanding long term impacts on these populations.  No
 significant  effects have yet  been quantified; it is still
 too  early  in the life  of the  project.
 SUMMARY AND CONCLUSIONS

     For  five consecutive summers,  secondary wastewater has
 been discharged to a peatland  in central Michigan.  Thus
 far, this  is a successful means of  advanced treatment.
 Results indicate that this is  indeed an effective means of
 nutrient  removal.  The wetland is large (7 square kilo-
 meters) ,  and therefore retained 100% of all added nutrients.
 But further, all nitrogen and  phosphorus were stored or
 removed within a five acre area, at a discharge rate of
 100,000 gallons per day; and within a 50 acre area at
 1,000,000  gpd.  The maximum increase in water depth was
 15 cm at  the center of a single point discharge.  During
 the 1976  drought, the discharge created the only remaining
 surface water.
     Nutrient fronts appear to be moving slowly downgra-
 dient.
     Inactive dissolved species, such as chloride, flowed
 through the active area with very little change.  The pH
 of the added water was high compared to the slightly acid
 wetland waters, but dropped rapidly to background levels
 as the water traveled across the wetland.   There was a
 similar pattern for conductivity:  high entering values,
 dropping rapidly to background.
     Neither a linear discharge, through numerous gates in
 irrigation pipe, nor a point discharge from a single pipe,
 caused any soil erosion or plant mortality.  Suspended
 solids from the treatment plant deposited very close to
 the area of discharge, and were not transported with the
wastewater.  Visual effects were minimal:   itensified green
 color in plants, and slightly  (5-10 cm)  deeper water near
 the discharge.   Odor problems were slight or non-existent.
The wastewater was of quite low heavy metal content, and
hence no information on this potential contaminant was
obtained.   Coliform bacteria and virus were present in both
 the discharge and in the natural wetland in comparable
numbers.
     The animal populations exhibited little response to
the discharge.   There was no change in bird activity or
numbers, nor was there noticeable effect on larger mammals.
     The fate of the added nutrients is in the soil, litter
 and plants near the discharge.   Exact proportions cannot be
 determined, because of the large natural pool of these
materials.  Based on lab studies/ it is clear that processes
                         134

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such as sorption, ion exchange, and precipitation remove
some added constituents, such as phosphorus.  It is quite
likely that microbial denitrification plays an important
role in nitrogen removal.  Uptake by algae and vascular
plants provides at least a temporary storage for some
nutrients, and perhaps a permanent storage of some fraction
of the added material.
     This peatland can accept treated wastewater during the
summer months without noticeably changing the character of
the wetland over periods of one to two years.  The nutri-
ents (nitrogen and phosphorus) are removed, but some dis-
solved materials (sodium and chloride) are not.
ACKNOWLEDGMENTS

     The Houghton Lake Wetland Treatment System was built
and placed in operation during the first six months of
1978.  An operation and maintenance plan has been developed,
and the system operates successfuly.  This remarkable
achievement was made possible by the excellent cooperation
of the National Science Foundation, Environmental Protec-
tion Agency, Michigan Department of Natural Resources, the
U.S. Fish and Wildlife Service, Roscommon County, the
Houghton Lake Sewer Authority, Williams and Works, Inc.,
and the University of Michigan.
     This paper is based on the work of many people, in-
cluding all those referenced in the Related Publications
list.  In addition, University of Michigan field operations
were successfully guided by Mr. Richard J. Kruse.
RELATED PUBLICATIONS

1.  Progress Reports;

Kadlec, John A., Kadlec, Robert H., Parker, Peter E., and
Dixon, Kenneth R.  "The Effects of Sewage Effluent on Wet-
land Ecosystems."  Progress Report.  July 1, 1972 to April
1, 1973.

Kadlec, John A., Kadlec, Robert H., and Richardson, Curtis
j.  "The Effects of Sewage Effluent on Wetland Ecosystems."
Progress Report.  April 1, 1973 to March 1, 1974.

Kadlec, John A., Kadlec, Robert H., and Richardson, Curtis
J.  "The Effects of Sewage Effluent on Wetland Ecosystems."
Semi-Annual Report No. 1.  May 1974.

Kadlec, Robert H., Richardson, Curtis J., and Kadlec, John
A.  "The Effects of Sewage Effluent on Wetland Ecosystems."
Semi-Annual Report No. 2.  November 1974.
                                135

-------
Kadlec, Robert H., Richardson, Curtis J., and Kadlec, John
A.   "The Effects  of  Sewage Effluent on Wetland Ecosystems. "
Semi-Annual Report No.  3.  May 1975.

Kadlec, Robert H., Richardson, Curtis J., and Kadlec, John
A.   "The Effects  of  Sewage Effluent on Wetland Ecosystems."
Semi-Annual Report No.  4.  November 1975.

Kadlec, Robert H., Tilton, Donald L., and Kadlec, John A.
"Feasibility of Utilization of Wetland Ecosystems for
Nutrient Removal  from Secondary Municipal Wastewater Treat-
ment Plant Effluent."   Semi-Annual Report No. 5.  June 1977,

Kadlec, Robert H., Hammer, David E., and Tilton, Donald L.
"Wetland Utilization for Management of Community Waste-
water." Status Report.  October 1978.

Kadlec, Robert H., Hammer, David E., Tilton, Donald L.,
Rosman, Lisa, Yardley,  Brett.  "Houghton Lake Wetland
Treatment Project."  First Annual Operations Report.
December 1978.

Kadlec, Robert H., Tilton, Donald L., and Schwegler,
Benedict R.  "Three-year Summary of Pilot Scale Operations
at Houghton Lake."  Report to the National Science Founda-
tion.  February 1979.

Kadlec, Robert H., Ed., "Wetland Utilization for Management
of Community Wastewater."  1978 Operations Summary.  March
1979.  Report to NSF-ASRA.
2.  Monographs:

Dixon, K. R., and Kadlec, J. A.  "A Model for Predicting
the Effects of Sewage Effluent on Wetland Ecosystems."  The
University of Michigan, Ann Arbor, Publication Number Three
February 1975.

Richardson, C. J. , Kadlec, John A., Wentz, A. W., Chamie,
J. P. M., and Kadlec, Robert H.  "Background Ecology and
the Effects of Nutrient Additions on a Central Michigan
Wetland."  The University of Michigan, Ann Arbor, Publica-
tion Number four, June 1975.

Parker, P. E., Gupta, P. K., Dixon, K. R., Kadlec, R. H.,
Hammer, D. E.  "REBUS - A Computer Routine for Predictive
Simulation of Wetland Ecosystems."  August 1978.

Schwegler, B. R., and Kadlec, R. H.  "Wetlands and Waste-
water."  Pamphlet.  1978.
                         136

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3.  Theses;

Bergland, Mark S.  "Foraging Ecology of the Female Red-
Winged Blackbird."  M.S.  Thesis.  The University of Michi-
gan, Ann Arbor, 1975.

Bergland, Mark S.  "Foraging Behavior of Red-Winged Black-
birds Breeding in a Wetland Ecosystem."  Ph.D. Thesis.
The University of Michigan, Ann Arbor, 1978.

Chamie, Jim P. M.  "The Effects of Simulated Sewage
Effluent upon Decomposition, Nutrient Status and Litter-
fall in a Central Michigan Peatland.  Ph.D. Thesis.  The
University of Michigan, Ann Arbor, 1975.

Croson, Susan C.  "Distribution and Abundance of Insects in
a Wetland Ecosystem."  M.S. Thesis.  The University of
Michigan, Ann Arbor, 1975.

Dixon, Kenneth R.  "A Model for Predicting the Effects of
Sewage Effluent on Wetland Ecosystem."  Ph.D. Thesis.
The University of Michigan, Ann Arbor, 1974.

Gupta, Prem K.  "Dynamic Optimization Applied to Systems
with Periodic Disturbances."  Ph.D. Thesis.  The University
of Michigan, Ann Arbor, 1977.

Maguire, Lynn A.  "A Model of Beaver Population and Feeding
Dynamics in a Peatland at Houghton Lake, Michigan."  M.S.
Thesis.  The University of Michigan, Ann Arbor, 1974.

Parker, Peter E.  "A Dynamic Ecosystem Simulator."  Ph.D.
Thesis.  The University of Michigan, Ann Arbor, 1974.

Scheffe, Richard D.  "Estimation and Prediction of Summer
Evapotranspiration from a Northern Wetland."  M.S. Thesis.
The University of Michigan, Ann Arbor, 1978.

Schwegler, Benedict R.  "Effects of Sewage  Effliient on
Algal Dynamics of a Northern Michigan Wetland."  M.S.
Thesis.  The University of Michigan, Ann Arbor, 1978.

Wentz, W. Alan.   "The Effects of Simulated  Sewage Effluents
on the Growth and Productivity of Peatland  Plants."  Ph.D.
Thesis.  The University of Michigan, Ann Arbor, 1975.
4.  Utilization Reports;

Kadlec, Robert H., Tilton, Donald L.   "Monitoring Report
on The Bellaire Wastewater Treatment Facility."  Utilization
Report No.  1.  August  1977.
                                137

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 Kadlec, Robert H., Tilton, Donald L.   "Monitoring Report on
 the Bellaire Wastewater Treatment Facility,"  Utilization
 Report No.  2.  March  1978.

 Kadlec, Robert H., "Monitoring Report  on the Bellaire
 Wastewater  Treatment  Facility."  Utilization Report No. 4.
 February 1979.
 5.  Papers:

 Croson, S. and Witter, J. A.   "Distribution and Abundance
 of Mosquitoes in a Wetland Ecosystem."  North Central
 Branch, Entomological Society  of America, Proceedings.
 1975.

 Haag, Robert D., "The Hydrogeology of the Houghton Lake
 Wetland."  The Michigan Academician, 1979.  In progress.

 Kadlec, R. H.  "Wastewater Treatment via Wetland Irrigation:
 Hydrology."  Proceedings of the Waubesa Conference on
 Wetlands, Madison, Wisconsin,  1978.

 Kadlec, R. H., Tilton, D. L.   "Nutrient Dynamics in
 Effluent-Irrigated Wetlands."  Proceedings of the Kissimmee
 Symposium on Freshwater Wetlands, Tallahassee, Florida,
 1978.

 Kadlec, R. H., Tilton, D. L.   "The Utilization of Fresh-
 water Wetlands for Nutrient Removal from Secondarily Treated
 Wastewater.  1979.  Journal of Environmental Quality.  In
 progress.

 Kadlec, R. H., Tilton, D. L.   "The Use of Wetlands as a
 Tertiary Treatment Procedure."  CRC Press.  1979.  In press.

 Kadlec, R. H.  "Wetlands for Tertiary Treatment."  Pro-
 ceedings of the National Symposium on Wetlands, Lake Buena
 Vista, Florida.  November 1978.  In progress.

 Kadlec, R. H., Kadlec, J. A.   "Wetlands and Water Quality,"
Proceedings of the National Symposium on Wetlands, Lake
Buena Vista, Florida.  November 1978.  In progress.

 Kadlec, J. A.  "Nitrogen and Phosphorus Dynamics in Inland
 Freshwater Wetlands,"  Proceedings of the Symposium on
Waterfowl and Wetlands,  Midwest Wildlife Conference.
Madison, Wisconsin, 1978.  In press.

 Parker, Peter E., and Kadlec, Robert H.  "A Dynamic Eco-
 system Simulator."  Paper presented at A.I.Ch.E. 78th
 National Meeting, Salt Lake City, August 1974.
                         138

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p.ichardson, C. J., Tilton, D. L. , Kadlec, J. A., Chamie,
J. P. M.,  and Wentz,  W. A.  "Nutrient Dynamics in Northern
Wetland Ecosystems."   In R. E. Good, R. L. Simpson, and
D. F. Whigham, Eds.  Freshwater Marshes:  Present Status,
Future Needs.  Academic Press, N.Y., 1978.

Tilton, Donald L.  "Wastewater Treatment via Wetland
Irrigation:  Nutrient Dynamics."  Proceedings of the
Waubesa Conference on Wetlands, Madison, Wisconsin, 1978.
6.  Conference Proceedings;

Tilton, D. L., Kadlec, R. H., and Richardson, C. J.  "Fresh-
water Wetlands and Sewage Effluent Disposal."  Proceedings
of the NSF/RANN Conference on Freshwater Wetlands and
Sewage Effluent Disposal.  University of Michigan, Ann
Arbor, Michigan, May 10-11, 1976.

Sutherland, Jeffrey C. and Kadlec, Robert H., Eds.  "Fresh-
water Wetlands and Sanitary Wastewater Disposal."  Confer-
ence Abstracts, July 1979.
                                139

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            ENGINEERING,  ENERGY AND EFFECTIVENESS FEATURES

               OF MICHIGAN WETLAND TERTIARY WASTEWATER

                          TREATMENT SYSTEMS
T. C. Williams, Chairman of the Board,  Williams & Works,  611  Cascade West
     Parkway, S.E., Grand Rapids, Michigan  49506

J. C. Sutherland, Studies Manager, Williams & Works
                               ABSTRACT

Two markedly different Michigan wetlands are receiving pond stabilized
secondary treated non-chlorinated wastewater.  Both operations result in
removal of 98%-100% of phosphorus through contact with reactive soils.

At Vermontville (42°37'N, 85°OTW) flood irrigation fields (11.5 acres)
overgrown with volunteer wetland vegetation (mainly cattail)  treat and dis-
pose of wastewater principally by slow seepage (4 in./wk) through phosphorus-
adsorbing clayey-silty glacial till.  Occasional  uncontrolled runoff of
wetland surface waters releases phosphorus, BOD,  and suspended solids in
concentrations slightly above permitted limits.  Seepage wetlands offer
potential advantages compared to upland spray irrigation for small commun-
ities.  Savings of 25% and greater on capital plus land costs can be expected
for flow below 0.1 MGD average flows.  Field maintenance may not be needed,
and irrigation energy costs need be no higher than those for surface irriga-
tion of uplands.

At Houghton Lake  (44°18'N, 85°50'W), natural state-owned wetlands (600 acres)
treat  and dispose of wastewater by overland flow across a reactive peat sub-
strate.  Construction and maintenance in 1978 involved negligible ecological
impact. Construction was done in the dormant months between March and June.
The wetland transmission and  irrigation pipelines are strapped to a wooden
walkway suspended 2.5 ft above the wetland on pole pilings anchored in clay.
The cost of the wetland wastewater distribution system was $21.00/ft  (1979
dollars).  Irrigation electrical energy costs were approximately $7.21 in
1979.  The wetland capital and land costs  represent savings of approximately
$1 million compared to upland irrigation.
                                          141

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                               FOREWORD
The engineering-related features of the Houghton Lake and Vermontville,
Michigan, wetland wastewater treatment systems are presented and discussed
herein.  The environmental responses and details of wetland water quality
at the Houghton Lake site are presented in this volume in a separate paper
by Robert H. Kadlec.  The phytosociology, phenology, and wildlife habitat
attributes of the Vermontville wetland site were studied by Frederick B.
Bevis and have been previously distributed and presented (1,2).   Some of the
included engineering documentation related to Vermontville was distributed
or presented earlier this year (1,3) and similarly for Houghton  Lake (4,5).
Additional background on the Houghton Lake facility is presented in reference
15.
                                    142

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                           PART I:   VERHONTVILLE

                               INTRODUCTION


The municipal  wastewater treatment  system at  Vermontville,  Michigan  (popula-
tion 975), consists of two facultative stabilization  ponds  of  10.9 acres,
followed by four diked surface (flood) irrigation  fields  of 11.5  acres  con-
structed on silty-clayey soils.  The system  is  located on a hill  with the  ponds
uppermost and the fields at descending elevations  (Figures  1 and  2).  Now  in
their seventh year of operation,  the fields  are nearly overgrown  with volunteer
emergent aquatic vegetation, mainly cattail.

The Vermontville system is one of several pond  and irrigation  systems constructed
for sanitary wastewater treatment in the late 1960's  and  early 1970's in Michigan.
It was one of the first such systems to go into operation in this state.   There
was one very specific need among  others which led  to  the  introduction of upland
irrigation systems in Michigan.  That need was  phosphorus (P)  removal.   In 1968
the Lake Michigan Enforcement Conference of  the FWPCA (the EPA forerunner) deter-
mined that communities in the Lake  Michigan  Basin  must remove  80% of the P from
sanitary wastewater before discharging it to streams.

Vermontville's system was conceived and designed with phosphorus  removal and
economy of operation in mind.  The  ponds would  receive raw wastewater alter-
nately with a week-on, week-off schedule.  The  upper  pond (PI, Figure 2),  has
separate discharge lines into fields Fl and  F2  and the lower pond (P2)  has
separate discharge lines into fields F3 and  F4.  Pond-stabilized  wastewater
would be released into each field by gravity flow  through 10-in.  main and  8-in.
manifold pipe having several ground level outlets  in  each field.   Irrigation  of
terrestrial grasses would take place during  six of the spring-summer-fan  months.
Up to 4 inches of wastewater applied each week  would  flood the fields briefly
until the water seeped away.  Should the water level  exceed 6  in. or so, water
would overflow to the next field  by means of a  standpipe  drain.  It  was expected
that all applied water would seep into the ground  before  leaving  the treatment
area.

The system's actual operation and the general hydraulic behavior  of  the fields
are essentially as conceived; although in actual  operation the fields  often do
overflow when wastewater is being released into them, or following  hard rainfall,
nearly all of the irrigated wastewater seeps into  the ground.   But  there are  some
significant departures from the conceived system.   Water stands in  the  fields for
hours or days at a time, and the fields are heavily overgrown  with wetland vege-
tation.  Actually, cattails began to establish a year before irrigation was begun
and while the ponds were being filled for the first time.  Also,  although  the
final field (F4) is never irrigated, there is at all  times a surface discharge
from F4 into a stream.  At most times this surface discharge is dominantly re-
cycled wastewater, which is wastewater that has seeped through the  ground  from
the upper fields, and then re-emerged as springs into F4.  The quality  of  the
spring water is very high.  The spring water is occasionally augmented  with sur-
face wastewater overflow from  F3, under which condition the quality  of  the surface
                                          143

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          HOUGHTON

             LAKE
       ND   LAKE
       DS. vODESSA
                .LANSING
        VERMONTVILLE

      'PAW PAW
                   ETROIT
           LEON!
           TOWNSHIP
FIGURE 1,
MICHIGAN LOCATIONS W1IF.RF. MUNICIPAL WASTLJWATER-

WETLAND EFFECTS ARE BEING INVESTIGATED
              144

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    .
en
    ^ i
               ,    -
         FIGURE  2.   WASTEWATER  STABILIZATION  PONDS  (P)  AND  IRRIGATION  FIELDS  (F):   VERMONTVILLE.

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 discharge  from F4 is not as high as it is required to be.  Both of these de-
 partures - wetlands in place of terrestrial  vegetation and the related existence
 of  the  surface discharge of variable quality, invite questions about the econo-
 mics and effectiveness of treatment attending incidental  or deliberate inclusion
 of  seepage wetlands.  In 1978, the National  Science Foundation granted us  funds
 to  investigate the Vermontville system to identify any features which might  be
 advantageous in economical wastewater treatment for small communities (NSF ENV-
 20273).


                       SOILS AND THE RATE OF SEEPAGE

 The treatment site is located on glacial  till.  Extensive cutting and filling
 of  the  till soils were necessary to rough grade the irrigation fields at the
 time of construction.  Numerous borings taken in the irrigation fields reveal
 the upper 4 1/2 ft of inorganic soils to  be  sandy clay,  silty clay,  and clayey
 silt, with subordinate clay, clayey sand, silty sand, and fine-gravelly variants
 of most of the forenamed textures.

 Fifteen (15) split-spoon soil  samples from the upper 4 1/2 ft including most
 of  the mixed soil types named above were  tested for hydraulic conductivity
 (h.c.)  in the laboratory using falling-head  permeameters.  The observed range
 of  the  lab h.c. is 1.3 x 10~8 cm/sec for  an  impure clay  to 1.4 x 10"5 cm/sec
 for one impure sand sample.   Among all  samples, only the  impure sand showed a
 higher h.c. than 5.8 x 10"'  cm/sec.

 The seepage wetlands transmit wastewater  at  the observed  average rate of at
 least 4 in./wk, or 2.5 x 10"^ cm/sec, similar to the h.c. of the impure sand
 sample tested.   Yet a total  of 27 borings in the overall  treatment site indicates
 that sand as clean as the impure sand is  a minor soil  type here.   The higher
 actual  field permeability compared to the lab samples  could be due to compaction
 of soil samples in the lab in spite of counter-efforts, or to the (undiscovered)
 occurrence of sandy zones which may be areally minor,  but effective  as  seepage
 areas.   Equally likely is residual  looseness within the extensive volumes  of
 clayey fill in the wetlands, with attendant  random networks of irregular openings
which facilitate seepage.  Most areas of  filling are low-lying compared to the
 cut areas, and have been so  since shortly after final  grading.   This feature
 does not, however, appear to shed useful  light on the  state of openness of the
 fill.   One, or a combination of the named factors, could  be significant with
 respect to the observed rate of seepage.


                        ENVIRONMENTAL WATER  QUALITY

The average quality of the influent, pond effluent, wetland water, ground  water
and final  surface overflow is  shown in Figure 3.  Incidental  to the  more impor-
tant quality aspects, but requiring explanation nevertheless, is  the dilution
of wastewater (chloride)  as  it flows across  the system.   Chloride decreases
 persistently from 280 mg/1  in  the influent to 123-124  mg/1  in the ground and
 final  overflow waters.   Heavy  snow diluted the influent wastewater accumulating
                                     146

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ENVIRONMENTAL
WATER QUALITY
Cl ..
NH3-
NO3-
TKN
P
...280 mg/l
N . . 37 »
N 	 1.3 "
...81 "
5.3 »
-°\
y > >
INFLUENT
67,000 GAL/DA
Cl
NH3-N
NO3-N
TKN
P
—7
\PONDS
124
0.7
1.4
3.7
0.04
.207 ..157
. ... 2.5 20
... 10 ... 1.2 Cl 123
....6.5 ....5.0 P 0.
.... 1.8 ....2.1 BOD 5.

/ - WETLAND SS 20
/ •'•'•' FIELDS O/
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 in  the  ponds between late fall, 1977 and June, 1978, such that the average pond
 effluent showed 207 mg/1 Cl over the June-to-December 1978 irrigation season.
 Rainfall 50% above normal, and the coincidence of several sampling visits  with
 rainy periods, account for the 30% dilution of wetland standing water relative
 to  pond effluent.  The seepage-derived ground water is 25% to 30% diluted  with
 respect to wetland water because of mixing with ambient ground water.  The final
 surface overflow consists of soil-filtered wastewater derived from the three
 upper wetlands which is further diluted by rainwater in the fourth and final
 field.

 Phosphorus is higher in the wetland fields than in the pond effluent.   Even
 with dilution,  total  phosphorus increases from 1.8 mg/1  (pond discharge) to
 2.1 mg/1 in the wetland waters.  Decomposing detrital  organic matter  is  a  likely
 source of additional  P.  Also, the standing wetland crop loses  P over the  ir-
 rigation season.   Some amount of the lost P is perhaps stored in plant roots
 and rhizomes, but much of the lost P is likely released  directly into the
wetland water.   Approximately 97% removal  of P occurs  between the wetland  fields
 and the ground  water,  which is sampled from monitoring wells  placed at depths
 ranging from roughly 10 ft to 25 ft below the wetland  floors.   Most removal
of P occurs in  the upper 3 ft of soils judging from a  small  number of porous
cup lysimeter samples  which average 0.1 mg/1  total  P and 0.06 mg/1 ortho-P,
with ranges of  0-0.3 mg/1  and 0-0.2 mg/1,  respectively.   The  average  removals
of P effected in  the upper 3 ft of soils are approximately  95%.   Phosphorus
 is reduced to 0.04 mg/1 in the ground water which  is well below local  NPDES
 stream discharge  requirements of 0.5 mg/1  P.

 The immediate foregoing information documents the wetlands  as an incidental
 factor  in the treatment effected through the flood irrigation system, which
 reduces P to values well below the required 20% quantity and 0.5 mg/1 concen-
 tration limits.

 If  the wetland waters were permitted to overflow into a receiving stream,  the
 NPDES limits for P of 0.5 mg/1 (final column of numbers, Figure 3) could not
 be  met.  In fact, occasional surface overflow of wastewater from F3  into F4
 causes  the average final overflow from F4 to be slightly in excess of the  NPDES
 limits  for P, BOD and SS (final two columns of numbers, Figure 3).  Neither  BOD
 nor SS was measured in the ground water samples.  General absence of literature
 and first hand data which would imply significant levels of BOD and  SS remaining
 in  sanitary wastewater filtered through several feet of fine textured soils
 made us believe the BOD and SS would be unremarkable in the ground water.

 The F4  overflow quality data support data obtained by others under somewhat
 different circumstances which suggest that the flow-through process  in wetlands,
 absent  filtering of wastewater through native soils, might not provide sat-
 isfactory removal of phosphorus and other potential pollutants (references 6
 through 9).
                                    148

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                          OPERATION  AND  MAINTENANCE

 The Seepage Area

 The wetland fields  have  not  been  maintained  since they were put into use in 1973
 They seem not to require maintenance.   Maintenance  factors which characterize
 upland irrigation such as  encrustation  of the  uppermost soil surface (tightening
 of soils),  and accumulation  of  the  standing  crop (necessitating removal to control
 animal  pests, for example) do not appear to  be present.

 The potentially harvestable  wetland biomass  (mostly cattail) is reduced to a
 cattail  straw mat over the dormant  months.   The wastewater wetlands may act
 similarly to  natural  seepage wetlands established on glacial soils which have
 apparently  seeped effectively for centuries.   The absence of fine detrital
 inorganic sediments is a plausible  common factor in the seepage longevity of
 both the wastewater-developed and natural seepage wetlands.  Mineral silt and
 clay in  the raw wastewater may  effectively settle out in the stabilization
 ponds.   The irrigation inlet pipe inverts are  only  1.5 ft above the sloping (1-3)
 pond sides,  but the inlet points  are located shoreward of the entire shallow
 settling basin  of each pond, which  may  also  help minimize the entrapment of
 mineral  detritus  during  irrigation.

 Energy Requirement

 The  operators visit the  site to open (morning) and close (afternoon) manually-
 operated irrigation valves twice  each workday during the 6-month irrigation
 season.   Each morning they record the daily influent volume at the final  col-
 lection  system  lift station, and  from there they make the first daily visit to
 the  site, a round trip site  visit of one mile.  The second site visit (early
 afternoon)  is a  separate round trip of two miles.  The Village pick-up truck
 will  use around  0.1 gal.  /mile on  these excursions.   Approximately one-third
 of the site time  is devoted to inspection of the ponds.

 The  annual  cost  of gasoline  involved with irrigation of the wetlands, based on
 the  above,  is:
Approximately $20.00 worth of gasoline is involved in mowing the lonq wetland-
facing berm slopes.

Use of electrical energy to operate the wetlands is indirect.   The ponds  are
elevated with respect to the wetlands in order that irrigation may be done  by
gravity.  Extra lift of 22.3 ft (the average difference between the elevation
of the ponds and fields) is involved, and the total  lift from  the final collection
system lift station to the influent wetwell  at the ponds is  84 feet   The energy
consumed at the final lift station in 1978 was 16.225 kwh for  which the Village
was charged $0.06 per kwh.  A monthly service charge of $5.00  was added to  each
billing.  The annual electrical  energy cost  to operate the wetlands is:

     (16,225 kwh x &06 x 22.3^ + (K ,  $5^0, .
                                          149

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 In  1978,  28.5 million  gallons were irrigated at an average electrical energy
 cost  of:

      $318.44/28.5 MG = $11.17/MG.

 The total energy costs including site visits for irrigation are $364 per year 	
 roughly $1.00 per day or $12.81/MG.

 Not uncommonly, the electrical energy costs of seepage wetland operation would
 be much lower than at Vermontville.  One hypothetical situation involves a pre-
 existing  secondary treatment facility from which effluent could be drained by
 gravity into a new lower-lying wetland.  Another situation would obtain where
 design of new secondary facilities and gravity-fed seepage wetlands need not
 include extra collection system lift station capacity to enable gravity oper-
 ation of  the wetlands.

 Labor

 Approximately ten man-weeks are invested in the wetland facility during late
 spring-early autumn irrigation season by the wastewater treatment staff.  No
 time  is given to the facility in the off-season.

 Analytical

 Monitoring of the surface overflow from the final  wetland field (F4)  involves
 costs of  $260/month for eight months, or approximately $2,000/year.  This cost
 figure is roughly twice that for a hypothetical seepage wetland system without
 a surface overflow but which might be monitored with three ground water wells
 on a  quarterly schedule.


                   DELIBERATE DESIGN OF SEEPAGE WETLANDS

 Factors which may mandate conscientious planning and design to optimize waste-
 water treatment and wildlife habitat, while minimizing construction and O&M
 costs and adverse environmental  impact, are:

     1.  Ground water quality regulations  (environmental  impact).

     2.  Need for "slow" seepage and spatial  variation in water depth with
         interspersion to promote variety  (wetland habitat development).

     3.  Need for rapid enough  seepage to  infiltrate all  applied wastewater
         without uncontrolled runoff (treatment).

The use of seepage  wetlands for wastewater treatment adds soil-filtered waste-
water to the existing ground water.   The soils  will  likely remove  phosphorus,
bacteria,  suspended solids, and BOD adequately  to  meet stream  water quality
requirements.   Nevertheless, state ground  water quality regulations often specify
that disposal  of wastewaters shall  not degrade  a usable aquifer.   The regulations
                                     150

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may apply even where filtered wastewater meets  drinking water quality standards.
Where the use of a potential  site  would  result  in  degradation of a developable
portion of an aquifer contrary to  regulations,  then  some means of post-seepage
retrieval of the filtered wastewater and approved  final discharge must be de-
signed.  In Michigan, this condition with respect  to upland  irrigation has often
involved a choice between recovery of irrigated wastewater with purge wells
followed by discharge to a stream, versus selection  of a different site located
on the nearest developable property to an influent stream.   In Michigan, a
nearby stream or its bordering lowland would almost  always be the natural line
of discharge for the most shallow  ground water  zone  within an indefinite dis-
tance landward of the floodplain.   A seepage wetland site at or near such a
stream floodplain boundary would be acceptable  without the need for post-seepage
treatment.  The availability of such a location would offer  clear O&M advantages
compared to pumping irrigated water out  of the  ground prior  to discharge to a
stream.

Design and construction of seepage wetlands would  be more straightforward if
the requirements for physical control of wastewater  were the same as in con-
ventional upland irrigation on well-drained soils.  The basic upland requirements
include soils which are adequately open  to accept  the design amount of waste-
water, and depth to the unconfined ground water adequate to  prevent excessive
rise in the water table due to irrigation.  The range of allowable application
rates is limited on the  low  side, but almost never  on thehighside.  With
seepage wetlands, however, the rate of application is usually limited on both
the high and  low ends because of the need to establish wetland vegetation and
to prevent uncontrolled runoff, respectively.  The low limit insures standing
water for many hours to several days at  a time, while the high limit prevents
surface water from rising to the level of uncontrolled overflow.

A seepage wetland could be constructed and operated  to follow one of several
schemes.  Assume humid-temperate conditions and low-relief wetland contouring
to provide water depth interspersion over a depth  range  of, say,  +0.3 ft  (drained,
but poorly) to -3 ft (well submerged).

On a site with natural conditions  of uniformly  restrictive  soils,  the design
weekly increment of wastewater applied intermittently during the week should
be planned to seep away in a little under a week's time  to  avoid overflow
during rainy periods.  There would be some time-variation  in water depth on  a
weekly cycle, typically two inches or more.  The relative  variation would  be
greater  in the shallower water areas than in the deeper  water  environments.
More uniform water depths could be maintained,  if desired,  by  applying water
continuously at a constant rate, equal to the rate of seepage, with  inter-
ruption  of irrigation during significant  rainfall.  With  the latter  approach,
the length of the irrigation season would probably be little different  from
that ensuing with intermittent irrigation.

A number of unified soil classes could be acceptable for seepage wetland settings
(Figure  4).  Siltiness is a general indication  of suitability.   Most soils within
the five more suitable classes — GM, SM, SC, OL, and MH are prevalently or
significantly silty.  Mixtures of the finer  sand grades  and  clayey  sands within
                                           151

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              FIGURE 4
    UNIFIED SOIL  CLASSES
 WITH  HYDRAULIC CONDUCTIVITY
            IO"3 to IO~6 cm/sec
CLASS
GM
SM
SC
TYPICAL NAMES
SILTY GRAVELS
a
GRAVEL- SAND -SILT
SILTY SANDS
a
SAND SILT MIXTURES
INORGANIC SILTS
VERY FINE SANDS
SILTY OR CLAYEY FINE SANDS
CLAYEY SILTS (LOW PLASTICITY)
WORKABILITY
GOOD
FAIR
FAIR
                to ICfe cm/sec
Ol_
MH
ORGANIC SILTS
ORGANIC SILTY CLAYS
(LOW PLASTICITY)
INORGANIC SILTS
MICACEOUS OR DIATOMACEOUS-
FINE SANDY OR SILTY SOILS
ELASTIC SILTS
POOR
POOR
MOST DESIRABLE RANGE  IO"4-IO'5 cm/sec
                    152

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the named soil  classes may also be suitable.   In  their natural  condition,  the
forenamed classes could be too permeable for  wetland  vegetation to  self-establish.
For example, design for four inches per week  application  would  call  for  hydraulic
conductivity of around 10~4-8 cm/sec,  which is  close  to the  lower limit  of
infiltration indicated for the first three classes  named.  But  the  openness  of
the soils can be reduced during construction  through  compaction.  Because
compaction may decrease the soil's water intake rating by an order  of  magnitude
or more, care in achieving the right degree of  compaction is called for.   The
GM, SM, and SC soils may be readily compactible (fair to  good workability).  The
OL and MH materials are usually difficult to  work and to  compact, and  the  OL soils
may support only light equipment.

An alternative approach to construction and operation is  selective  compaction
to achieve a suitable surface for direct application  of wastewater  (Figure 5) and
primary wetland establishment.  An uncompacted  perimeter  area contiguous with the
compacted surface would receive and seep away any overflow from the compacted
zone.  The entire area would be enclosed with low berms to prevent  uncontrolled
runoff.  In soils which  cannot be adequately tightened by compaction, closure
could be achieved with bentonite or clay while  preserving an open-soil perimeter
for overflow control.  This procedure might be  more expensive than  selective
compaction, but with it the seepage wetland solution  is technically applicable
in highly permeable sandy terrane as well as  in silty soils. The non-uniform
soil infiltration approach to seepage wetland construction would allow uniform water
depth to be maintained, even with considerable  latitude in application fre-
quency, while preventing uncontrolled runoff.

Where soil manipulation is employed, the affected soil depth will usually  be one
foot or less.  To maintain the integrity of the thin  "seal," young  willow  and
any other trees should be cut down at the whip  stage, because if these trees
were to fall over at maturity a substantial part  of the seal would  be  destroyed
as roots tear free of the ground.   Annual hand  cutting during late  winter  or
early spring dormancy should be a low cost routine.


                           CAPITAL AND LAND COSTS

Seepage Wetlands vs Upland Spray Irrigation

Capital costs for seepage wetlands are calculated and compared  to costs  for
spray irrigation.  The land required for direct use is assumed  to be the same
for both methods at application rate of 4 in. per week.  Therefore, the  purchase
costs of land for direct application, land clearing costs, costs for access
roadways, and costs for monitoring wells are  considered to be the same for both
methods.  Costs related to transmission pipeline from secondary treatment  faci-
lities including installation and pumping station are also considered  to be  the
same for both methods.  Square shape application areas and square total  areas
including isolation land are assumed.

The cost differences between the two methods  arise in requirements  for
chlorination, isolation land, site grading,  electrical power and irrigation
                                          153

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BERM
  OVERFLOW
  PERIMETER
                    J^m&

COMPACTED SOIL ZONE
                                BERM
FIGURE 5. RENDERING OF A SEEPAGE WETLAND

-------
Table 1.   Unique Unit Costs Assumed for Spray Irrigation  and Seepage
          Wetland Systems.

GENERAL
~~"I
R
S R
P I
R G
A A
T
I
0
N

S W
E E
E T
P L
A A
G N
E D
ITEM
LAND
CHLORINATION
FACILITIES
POWER
FACILITIES
SPRAY
EQUIPMENT

SITE
GRADING
GATED
IRRIGATION
PIPE
January 1977
$l,000/ac.
$25,000
$10,000
$3,000/ac

--
$21/ft
January 19792
$l,154/ac.
$28,838
$11 ,535
$3,460/ac.
. . - - - - - - - -

$4,000/ac.
$24.22/ft
  Michigan approximate cost figures (reference 10).
p
  Update of costs to January, 1979 (reference 11).

structures.  Spray irrigation is assumed to require  pre-chlorination and an
owned isolation perimeter 800 ft deep around the application site, as well
as irrigation structures and an electrical power facility.  No site grading
is assumed for spray irrigation.  Seepage wetlands  are assumed to require
200 ft of owned isolation land, site grading (irregular leveling and con-
struction of low berms), and irrigation structures.   Chlorination and an
electrical power facility are assumed not to be needed for the seepage wet-
land areas.  The "no power facility" assumption is  conditional upon effective
gravity flow between the secondary treatment site and the wetland.  An irri-
gation structure in the form of gated piping and support fixtures is assumed
for seepage wetlands.  The length of the structure  is assumed equal to one
edgelength (square) of the wetland area.

The assumed unit costs for unique components of the two methods are given in
the included Table 1.  The costs are based on general cost figures for Michigan
as of January, 1977 (10) and updated to January, 1979 (11).  The present wet-
land irrigation structure costs may be nearer the tabulated 1977 value of
$21.00 per foot than the $24.22 figure (Table 1), because the Houghton Lake
wetland irrigation structure costs $21.00 per foot in 1979 dollars.
                                          155

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   Table 2.  Assumed General Conditions, Unique Capital  Costs  for Seepage
             Wetlands and Spray Irrigation, and Overall  Cost Differences
G
E
N
E
R
A
L
I
SR
PR
R1
AG
YA
T
I
0
N
S W
E E
E T
P L
A A
G N
E 0
J
0 E
S R
T£
I
S
CONDITIONS
POPULATION 70 gal,/
AT THESE cap-da
UNIT lOOgal./
FLOWS cap-da
TOTAL DAILY
FLOWS (MGD)
TREATMENT
ACREAGE
ADDITIONAL
ISOLATION ACREAGE
ADDITIONAL ISOLA-
TION LAND COSTS (C)
SPRAY FACILITIES
COSTS
CHLORINATION
COSTS
POWER FACILITY
COSTS
SUBTOTAL SPRAY
COSTS (A)
GATED PIPE AND
FIXTURES
SITE GRADING
COSTS
SUBTOTAL WETLAND
COSTS (B)
A - B
...ASSUMING LOWER
LAND COST=$577/ac
...ALSO ASSUMING
LOWER GRADING
COST=$2,500/ac
COST DIFFERENCE RANGE
W
IRRIGATION 4-IN
444
311
0.031
4
78
90,012
13,840
28,838
11,535
144,225
10,100
16,000
26,100
118,125
73,119
79,119
70,000-
120,000
1,000
700
0.07
9
90
103,860
31,140
28,838
11,535
175,373
15,165
36,000
51,165
124,208
72,278
85,778
70,000-
125,000
1,778
1,245
0.124
16
101
116,554
55,360
28,838
11,535
212,287
20,200
64,000
84,200
128,087
69,810
93,810
70,000-
130,000
/WEEK, 6
2,778
1,945
0.194
25
113
130,402
86,500
28,838
11,535
257,275
25,275
100,000
125,275
1 32 ,000
66,799
104,299
65,000-
135,000
MO/YR
4,000
2,800
0.28
36
124
143,096
124,560
28,838
11,535
308,029
30,330
144,000
174,300
133,729
62,181
116,181
60,000-
135,000
5,444
3,811
0.38
49
136
156,944
159,540
28,838
11,535
366,857
35,385
196,000
231,385
135,472
57,000
130,500
55,000-
140,000
7,111
4,978
0.50
64
148
170,792
221 ,440
28,838
11,535
432,605
40,400
256,000
296,400
136,205
50,809
146,809
50,000-
150,000
Table 2 gives a detailed tabulation of unique costs for spray  irrigation  and
seepage wetlands, subtotals for each method, and overall  cost  differences for
daily wastewater flows in the range 0.031 to 0.5 MGD and the corresponding
application areas of up to 64 acres.

With the assumptions of Table 1, the costs of spray irrigation exceed  the seep.
age wetland system costs by nearly constant amounts within the given  range of
flows, averaging $129,689 with a standard deviation of $6,632  for the  entire
range of flows.  With a different assumption that land might be bought for
                                  156

-------
one-half the earlier assumed cost,  or $577 per acre,  spray  irrigation systems
would cost $73,119 more at 0.031 MGD, and $50,809  more  at 0.5  MGD.  Add  to  this
assumption the further assumption of site grading  costs at  $2,500  per acre
instead of $4,000 per acre, and the spray method costs  exceed  those for  the
wetland method by $79,119 at 0.031  MGD and $146,809 at  0.5  MGD.  Combining
the several assumptions, the approximate range of  cost  differences under different
assumed conditions would be $70,000 to $120,000 at 0.031 MGD and $50,000 to
$150,000 at 0.5 MGD.

Overall Capital Costs

Capital costs for spray irrigation  systems were calculated  in  great detail  for
ten Michigan communities in 1977 (10).  All spray  irrigation sites were  located
within three pipeline miles of secondary facilities.  The  range of wastewater
flows among the ten communities is  0.07 to 0.24 MGD.  The  assumed  rate of
application of wastewater in the earlier study was 2  in./wk.  Adjustment of
these earlier calculations with allowance for the  new assumed  rate of application
of 4 in./wk and for increases in costs over the two intervening years yields an
expression, C = 2,600 F + 145, where C is the capital-plus-land cost in  1,000's
of dollars and F is wastewater influent flow in MGD.  This  expression must  be
further adjusted upward by 15.4% to reflect changes in  construction costs (11)
and assumes similar changes in land costs between  January,  1977 and January, 1979.
The new cost versus flow expression for spray irrigation systems is C =  3,000  F
+ 167.3.   In Figure 6, a spray irrigation cost curve  based  on  this equation,
and the seepage wetland costs and cost savings listed as  A-B  costs in Table 2,
are plotted.  Seepage wetland capital cost savings are  greater than 26%  where
flows are less than 0.1 MGD, 14% at 0.25 MGD flows and  8%  at 0.5 MGD flows.
                                 DISCLAIMER

The Vermontville studies are supported through a grant from the National Science
Foundation to Williams & Works.  Any opinions, findings, and conclusions or
recommendations expressed in this paper are those of the authors and do not
necessarily reflect the views of the National Science Foundation.
                                           157

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    CAPITAL
  BASIS : 4-IN/WK , 26 WK/YR
      LAND $1153/AC
   1.5


 CO

 Q  1
^^ ^
o
o
    0
            QX/SEEPAGE
               WETLAND
               	-*-


             SEEPAGE
             WETLAND
             SAVINGS
            14%    8%
       -I	1	1	L.
     0  .1  .2  .3  4 .5
       FLOWS (MGD)
FIGURE 6.  CAPITAL COST COMPARISON
         158

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                        PART II:   HOUGHTON LAKE

                              BACKGROUND


Houghton Lake in Roscommon County (Figure 7)  is Michigan's largest inland
lake, and is a vacation haven for city dwellers from Michigan and surrounding
states.  The Houghton Lake area's Tri-Township treatment plant (Figure 8)
serves a seasonally variable population.  The winter and off-season population
is approximately 5,300, and the peak summer season population is around 13,500.
These figures are expected to increase to 8,000 and 16,900 by 1988, and to
10,300 and 22,400 by 1998.

Construction of "conventional" treatment facilities for stabilization and land
treatment of wastewater to serve the Houghton Lake community through 1978 was
completed in 1975.  Two aeration ponds of 5.2 acres each and 10 ft working
depth are followed  by three holding ponds of 29.5 acres total area and 8,5 ft
working depth.  The holding ponds are designed to discharge into eight seepage
beds of 5 acres, and into five flood irrigation fields totaling 85 acres.
There is holding pond storage capacity for 140 million gallons over the six
winter months, and the seepage and flood irrigation areas can treat 208 million
gallons annually—the 1978 design flow on an  average 81 gal./cap.-da basis.

The need for collection and treatment of wastewater from around Houghton Lake
was realized in the 1960's as residential and commercial septic system fail-
ures threatened the economic well-being of the area.  Even with increasing
numbers of summer lake dwellers and year around cottage homes—major con-
tributors to the problem—the area's financial base continued to be modest.
How to treat wastewater affordably was a question very much on everyone's
mind in 1968.   In this rural setting, stabilization ponds were the best choice
among secondary treatment alternatives, we thought.  Then in 1968, the Lake
Michigan Enforcement Conference of the Federal Water Pollution Control Admin-
istration (an EPA precursor) established that 80% removal of phosphorus would
be required before discharging into streams tributary to Lake Michigan.

At the time, there were no thoroughly tested alternatives to expensive mechan-
ical-chemical-biological  phosphorus removal systems.  The Pennsylvania State
University studies of the living filter system (12), however, were attracting
much interest.  The Michigan Department of Natural Resources (DNR) was cogni-
zant of the new burden that the phosphorus rule placed on rural communities.
Thus,  in 1970 when we recommended flood irrigation facilities, we had the
needed support  of the state even though very few municipal  irrigation facilities
were yet in operation in  Michigan.

By 1971, the Houghton Lake community had a conceived treatment system designed
for 600,000 gal. per day  that would serve them until 1978.  And it only  remained
                                           159

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                        OSCOMMON
                        COUNTY
                     ROSCOMMON
                      TOWNSHIP
FIGURE 7.  LOCATION  OF HOUGHTON LAKE, MICHIGAN
                      160

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               EXISTING  TREATM
                           TE
ROSCOMMON   TWP.
     FIGURE 8.  LOCATION OF TRI-TOWNSHIP WASTEWATER
              TREATMENT SITE, NOT INCLUDING WETLANDS
                          161

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 to locate land  for  expansion to 1998 design capacity.  But the cost of upland
 property was  increasing,  and although the option to purchase additional  upland
 remained open until  the spring of 1977, efforts to develop a more attractive
 alternative were  initiated  in 1971 and continued for seven years.

 Houghton Lake is  in  the very poorly drained headwaters of the Muskegon River
 and  there are thousands of  acres of swamps within a few miles of the service*
 area population.  It occurred to us that swamp lands south or west of the
 treatment area might be able to take the pond effluent and give it tertiary
 treatment.  The lands were  largely owned by the state and we thought they miqht
 be usable at  little cost.   Early in 1971 we met with the division chiefs  of
 the  Michigan  DNR to discuss the idea.   There was some discussion of the  swamps
 being infertile and unproductive, and perhaps wastewater nutrients would  be
 just the  thing to bring them to productive life.  The DNR was interested  but
 there were many questions and few reliable answers about the idea.  There was
 of course, little published information or experience at the time to support '
 any  far  reaching decisions.  But the DNR was interested enough to request that
 researchers at the University of Michigan, John and Bob Kadlec,  develop  an
 environmental  feasibility study and report.   Through the efforts of these
 researchers,  the National  Science Foundation came in to assist with virtually
 complete  funding of the wetland studies beginning in mid-1972.

 Between 1972 and 1977,  the researchers  identified the baseline characteristics
 of a wetland tract known as the Porter  Ranch peatland,  and tested the  peatland
with up to 100,000 gal./da quantities of pond stabilized wastewater.   The peat
 soil  substrate,  which is up to 4 ft and greater in thickness, is fragile.   Dur-
 ing the experimental period, the research project team  took special  care'to
minimize marking the wetland with  evidence of their ingress  and  study  activi-
ties.  This care was rewarded in there  being only one or two faint path marks
which persist  today. The evident sensitivity  of the peatland pointed to the
need for design  which would allow  environmentally compatible irrigation pipe-
line construction and operation.

                      TREATMENT EXPANSION ALTERNATIVES

The facilities plan  (13) compares  capital  and O&M costs  for the  wetland treat-
ment system (A), physical-chemical-biological  treatment  (B)  and  expansion  of
the existing upland  irrigation  treatment  system (C).  Table  3 below is a  tabu-
lation of the  January,  1976 costs  estimated  for the three  alternatives, A,  B,
and C.
Table 3.   Capital  Cost Comparison  for  Alternative Treatment Methods

Capital ($l,000's)
Construction
Miscellaneous
Land
I. Total Capital
II. O&M (20 years)
III. Salvage Value (20 years)
Net Present Worth (I+II-III)
A

591
158
0
749
320.5
32.5
1,037
B

1,730
370
0
2,100
901.3
54.3
2,947
C

1,108
262
184
1,554
316.5
l__127^5
1,743
                                   162

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Savings of $805,000 in capital  costs  were projected  for  the wetland  alterna-
tive compared to expanding the  existing upland irrigation  system.  Updating
to January, 1978, when construction contracts  were awarded, involved an  in-
crease in capital costs of approximately 16% (11), or projected  capital
savings of approximately $934,000.
                                   DESIGN
The Wetland Irrigation System
The wetland irrigation pipeline (Figures  9 and 10)  is  located  approximately
one-half mile out into the wetland,  in the downgradient direction  (southwest)
of surface water movement.  It was anticipated that backflow or backup  of  the
slowly-moving wetland surface water would occur during irrigation,  and  the
resulting flow, water level  and treatment effects  could best be documented
by allowing abundant upgradient distance  and area  between  the  pipeline  and
the northeast edge of the wetland.

Beneath the peat floor lie several tens of feet of glacial  lake bed clay.
Although the peat would be of no use as a bed for  a conventional  pipeline
arrangement, the underlying clay would present no  foundation problems.   Several
experiments, including flotation and pilings as support mechanisms, resulted
in the adopted design.

Wastewater is carried into the wetland through a 2500  ft-long  12-in.  aluminum
header pipeline.  This pipeline makes a tee connection at  the  center of a
3,200 ft-long gated aluminum irrigation pipeline.   Each arm of the  irrigation
pipeline is stepped down in size (Figures 10 and 11) from  the  tee connection to
outer end with 400 ft each of 12-in., 10-in., 8-in., and 6-in.  piping.   Waste-
water flow into each irrigation arm can be controlled  separately by 12-in.
aluminum butterfly valves (Figure 11).  Irrigation gates are positioned at
15-ft intervals.

The transmission and irrigation pipelines are supported above  the wetland
surface on a wooden walkway.  The walkway in turn  is supported above the wet-
land surface on a frame which is anchored in the clay  substrate.

The walkway consists of 2-in. x 6-in. x 32-in. hardwood planks nailed on 8-in.
centers to 2-in. x 8-in. rails.  The support frame for the walkway is made up
of separate units, each consisting of a pair of 2-in.  ID pipe  poles anchored
in the clay, and joined together by 2-in. x 6-in.  x 48-in. hardwood planks.
The planks are fastened to the pipe poles "edge-up," with  two  U-bolts per  pole.
The frame units are spaced 10 ft apart (Figure 12).

The pipelines are supported on one edge of the walkway directly over a  2-in.
x 8-in. rail.  The pipelines are strapped to the rail  with aluminum straps on
8 ft centers, and are supported laterally by contact with  the  2-in. pile pipes
(Figure 12).
                                           163

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                     WET LAND-
                     UPLAND
                     MARGIN
                                                     PROPOSED 12 FORCE
                                                     LINE
PROPOSED GATED
PIPE
                                     PROPOSED
                                     DECHLORINATION
                                     POND
          FIGURE 9.   LOCATION OF OLD  ("EXISTING") AND NEW
                      ("PROPOSED") TREATMENT FACILITIES
                               164

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                            / ^Cjfr *•
                                 .>—
-------
05
O)
                                                                                      B-B
                           FIGURE 11.   TEE AREA OF WETLAND IRRIGATION SYSTEM:  HOUGHTON LAKE

-------
                                             c-c
                                                                              AJbx/s
                                                                         V/
-------
The header and irrigation pipelines, fittings, and valves are welded aluminum
alloy with lock-ring couplers and gaskets.  The irrigation slide gates are of
high strength nylon and delrin.  The gates slide over rectangular orifices cut
in the pipe, in side-to-side fashion, from fully open to fully closed.

Other

Construction related to the wetland treatment scheme included modifications
and additional  structures at the upland treatment site.   Also, the regulatory
authority wanted assurance that neither pathogens nor residual chlorine would
reach the wetland.  Hence, the most significant new structure is a dechlor-
ination pond (DP) of 2.6 acres area and 12 ft depth (location shown in Figure
9).  In fact, the concern over pathogens which might survive the stabilization
ponds has diminished because fecal  coliform standards (200/100 ml) are being
met without chlorination.  Chlorination has not been done, and the dechlori-
nation pond has been used as an intermediate holding pond with two days capa-
city at 2 MGD.
                               CAPITAL COSTS

The capital costs include materials and labor for modifying the final  holding
pond, construction of the dechlorination pond, forceline  to the wetland,
irrigation header, irrigation lateral, wetland support structures,  and moni-
toring and analytical equipment.   The capital costs itemized below  are com-
plete except for engineering*, and except for research funds extended  by the
National Science Foundation for the initial  proof-of-concept period.

Holding Pond Modification

     Auxiliary pump structure            =       $ 6,500
     New and modified control structures =         4,400
     Leveling                            =           900
     Transfer pipe (to DP),
       20-in., 1,605 ft @ $16.69          =        26,787
                    Subtotal                      $38,587         $38,587

Dechlorination Pond

     Site preparation and excavation     =       $84,103
     Transfer pump structure              =        57,907
     Metering and control  structures     =        11,200
                    Subtotal                     $153,210         $153,210
* Design, construction inspection, hydrogeological  studies,  soils  studies,
  O&M manual, startup assistance, etc.
                                    168

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Pond-Wetland Transmission

     Forceline,  12-in.,  5,589 ft
       @ $14.00,  plus  bends               =       $80,646
     Air-release  and cleanout manholes   =         3,000
                    Subtotal                      $83,646         $83,646

Irrigation  Header System

     Header pipe, 12-in.,  2,500 ft
       @ $7.50                            =       $18,750
     Support Structure,  2,500  ft
       @ $12.97                           =        32,425
                    Subtotal                      $51,175         $51,175

jrrigation  Lateral  System

     Gated  pipe (12-in.,  10-in.,	
       6-in.)                             =       $18,864
     Support  structure
       3,200  ft @ $12.97                  =        41,504
     Valves,  bends, reducers,
       end  caps, tee                     =         1,224
                    Subtotal                      $61,592         $61,592

Monitoring

     Wells                                =       $ 1,830
     Analytical  equipment                =         7,890
                    Subtotal                      $ 9,720         $ 9,720
                    Total  Capital  Cost   =                      $397,930

                                                                $400.000


Capital  costs were offset  by'an 80% construction grant from the USEPA through
the 201  facilities planning program.   The design and award of Step 3 funds
occurred ahead  of the Clean Water Act of 1977 (14).   At present the Houghton
Lake Sewer Authority is  applying to the state and federal  construction granting
agencies to secure retroactive alternative and innovative  status for the wet-
land irrigation facility.
                                           169

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                     OPERATION AND MAINTENANCE  COSTS


 Wastewater  Composition

 Raw wastewater contains approximately 80-100 mg/1 BOD, 60-80 mg/1 suspended
 solids, and chloride of 100-110 mg/1.  The wastewater is comparatively weak,
 probably because of  long sewer lines.  Phosphorus and the nitrogens are
 typical of  normal domestic wastewaters.  Wastewater applied to the wetland
 has COD of  12 to 27 mg/1, total phosphorus of  4 to 5 mg/1, total dissolved
 phosphorus  of around 2 mg/1, nitrate-N of 1.2  mg/1, ammonia-N of 0-3.5 mg/1,
 fecal col i form of 150/100 ml and fecal streptococcus of 10/100 ml.

 Electrical  Energy for Wetland Irrigation Pumping

 Energy consumption for irrigating the wetland  includes that consumed in
 pumping from the dechlorination pond (DP) to the wetland.

 In 1979, 101 MG were applied to the wetland between June 18 and August 20,
 with one week of shutdown for forcemain repairs.  The average rate of
 irrigation  in this period was 2 MGD, with water being applied at rates up
 to 3 MGD.   Irrigation was often done round the clock.

 Layne-single stage vertical turbine pumps (Model 14THC) operate between the
 DP and the wetland, with roughly 82% efficiency at 1600 rpm and 40 ft TDH.

 The 1979 cost of pumping to the wetlands from  the DP is, therefore, approximately

     lOlxlO6 aal   x    1  f^   -- 62.4 1b    1   hp-sec       1  hr     0.746 KW
     IUIXIU  gal. x            x     3    x 550 ft-lb x 3,600 sec X - hp -
          f4. Tnu v $0 • 04       1           I
          Tt IUH x       x
                                       m.e.(85%)


The calculated cost per million gallons is $7.21/M6.

Other O&M for Wetland Irrigation

Other O&M costs include repair, inspection, environmental monitoring and
equipment.  For the first seven months of 1979 the itemized costs are:

     Irrigation pump (DP to wetland) and valve repair        $  191.00
     Semi-weekly inspection of the wetland system               400.00
     Ecological monitoring (graduate student) and             . Rn_
       lab analyses of environmental waters                   o,ouu.uu
     Laboratory equipment purchased                           1,200.00
                                    170

-------
For the remaining months of 1979,  assume repair and inspection  costs  to
continue as shown, ecological  monitoring to continue as shown through October
and no new lab equipment.   The total  anticipated O&M for wetland irrigation
in 1979, including irrigation  energy, is therefore,


     $728 + y- (191 + 400) + y-(5,800) + $1,200 = $11,227 or 111/MG .


Environmental  monitoring by the University of Michigan wetlands ecosystem
research group continues with  National Science Foundation support.   This
support is in  addition to the  $11,227 figure given above.

Overall Operating Costs

The wetland system O&M is approximately 20% of the total treatment O&M
budget for the Tri-Township system.  Total 1978 O&M costs for the complete
Tri-Township treatment facility include maintenance and clerical salaries
($28,500 including benefits),  electrical energy to pump wastewater ($13,409
including the final collection system lift station), insurance  ($8,362),
HVAC ($3,724), repair and replacement parts ($1,500), gasoline  ($1,000),
laboratory equipment ($654), postage and telephone ($500), custodial  sup-
plies  ($370),  and treatment personnel education ($150).  The total  1978
figure is $58,159.  Upward adjustment by 7.2% to the 1979 timeframe (11)
yields $62,357 for current annual  O&M costs.

The wastewater treated and disposed in 1979 was 101 MG  (wetland) and 29 MG
(seepage beds), for a total of 130 MG.  The unit O&M costs for  the entire
Tri-Township treatment system are around $300/MG, because the flow to the
treatment site is 198.5 MG/year with 68.5 MG being pond leakage or meter
disagreement.

Because so many of this system's costs are fixed costs  unrelated to flow,
we calculate (without inflation) that, at design flow,  the total O&M cost
(including both collection and AWT) will fall to around $200/MG.

The design flows  for the year 1998 are:

     Annual average of 1.1 MGD
     Eight-day peak flow of 1.85 MGD

The residential sewage service charge is $75/year, regardless of days of
occupancy.  Front foot assessments for local sewer construction ranged  from
$10 to $13/front  foot.

Williams & Works1 operation and management staff screened, hired and trained
all permanent operating personnel, because the operating authority (Houghton
Lake Sewer Authority) was a newly created public agency.
                                      171

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                                REFERENCES
3.
     Williams & Works, Inc. (1979).  Reuse of Municipal Wastewater by
     Volunteer Fresh-Water Wetlands.  Interim report to the National
     Science Foundation:  ENV-20273 (April).

     Bevis, Frederick B. (1979) "Ecological Consideration in the Manage-
     ment of Wastewater - Engendered Volunteer Wetlands,"  in Conference
     Abstracts:  Wetland Utilization for Management of Community Waste-
     water, Higgins Lake, Michigan, July 10-12, 1979.  (Tables available
     from the author).

     Sutherland, J. (1979) "The Vermontville, Michigan, Wastewater-Grown
     Volunteer Seepage Wetlands:  Water Quality and Engineering Implica-
     tions," in Conference Abstracts:   Wetland Utilization for Management
     of Community Wastewater, Higgins Lake, Michigan, July 10-12, 1979.

4.   Jones, R. C. (1979) "Design and Construction Aspects of the Houghton
     Lake Wetland Irrigation Project,"  in Conference Abstracts:  Wetland
     Utilization for Management of Community Wastewater, Higgins Lake,
     Michigan, July 10-12, 1979.

5.   Williams, T.C. (1979) "The History and Development of the Houghton
     Lake Wetland-Wastewater Treatment Project,"in Conference Abstracts:
     Wetland Utilization for Management of Community Wastewater, Higgins
     Lake, Michigan, July 10-12, 1979.

6.   Sloey, W. F., Spangler, F.L. and Fetter, C.W.,Jr.  (1978) "Management
     of Freshwater Wetlands for Nutrient Assimilation," in  Freshwater
     Wetlands (Ecological Processes and Management Potential) (R.E.  Good,
     D. F. Whigham and R. L. Simpson,  editors). Academic Press, pp 321-340.

7.   Lee, G.F., E. Bentley, and R.  Amundson (1969) "Effect of Marshes on
     Water Quality (mimeo)." Water Chemistry Laboratory.  Madison, Wisconsii

8    Bender, M.E. and D.L. Correll  (1974) The Use of Wetlands as Tertiary
     Treatment Systems.  NSF-RA-E-74-033.  NTIS PB-241002 (June).

9.   Fritz, W.R. and S.C. Helle (1977)  Tertiary Treatment of Wastewater
     Using Cypress Wetlands.  Preliminary Report:  NSF-ENV-76-23276
     (November).

10.  Sutherland, J. (1977) Investigation of the Feasibility of Tertiary
     Treatment of Municipal Wastewater Stabilization Pond Effluent Using
     River Wetlands in Michigan.  Final  Report to the National Science
     Foundation (NSF ENV 76-20812 and NTIS PB 275-283).
                                    172

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                          REFERENCES (Cont.)


11.   Engineering News Record Construction cost indexes.

12.   Parizek, R.R.  et al,  (1967), "Waste Water Renovation and Conservation,"
     The Pennsylvania State University Studies No. 23.  71 pp.

13.   Williams & Works (1976), Houghton Lake Area Facilities Plan, Step I,
     Federal  Project C-262768 (April).

14.   Federal  Register, Vol. 43, No. 188 (43FR 44022), September 27, 1978:
     EPA Municipal  Wastewater Treatment Works Construction Grants Program.
     Rules and Regulations.

15.   Williams, T.C. and Jeffrey C. Sutherland (1979) "Houghton Lake, Michigan,
     Peat Wetland Tertiary Treatment System," Water Pollution Control Federa-
     tion Conference (Session 44), Houston (October).
                                       173

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Aquatic Plant Process*
Session

-------
    Photo of a large pond in San Juan, Texas covered by water
hyacinths to help improve water quality. Inserts depict water
hyacinths being harvested from the Disneyworld water hyacinths
testing facility at Lake Buena Vista, Florida and a duckweed
covered treatment pond near North Biloxi, Mississippi.

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                AQUATIC PLANT PROCESSES:   SESSION SUMMARY
Presentations in this session covered wastexvater treatment utilizing vas-
cular aquatic plants with water hyacinth (Eichhornia crassipgs) being the
predominate plant discussed.  The potential of more cold tolerant plants
such as duckweed for treating domestic wastewater was briefly discussed.

Results of these studies clearly demonstrate the potential of higher plants
in both domestic and industrial wastewater treatment.  Wastewater lagoons
are the most popular and inexpensive method of treating domestic wastewater
in small communities.  Data on upgrading sewage lagoons in Mississippi and
Texas presented during the seminar demonstrated the potential for using
this technology for improving the performance of lagoons located in warmer
regions of the United States.  Potential problems associated with using
water hyacinth to upgrade sewage lagoons were identified along with sug-
gested solutions.

When plant coverage is complete, single cell lagoons with 6605 loading
rates in excess of 40 kg/ha/day without aeration are subject to producing
odors, especially at night when the plants are not photosynthesizing.  Multi-
celled lagoons with surface aerators in the raw sewage cell and single cell
lagoons with maximum BOD^ loading rates of 30 kg/ha/day are the best candi-
dates for upgrading these lagoons using water hyacinth or duckweed.

Data on the use of water hyacinth for tertiary treatment in Florida was
presented.  The data suggest that all parameters for tertiary treatment
with the possible exception of phosphorus can be met in south Florida
using approximately one acre of water hyacinth per 379 m3/day of wastewater
effluent from an activated sludge plant.  Because the ratio of NrP  in water
hyacinth plant tissue is approximately 6:1 and the ratio in wastewater
approximately 3:1, nitrogen is depleted first and becomes a limiting factor
before the phosphorus is reduced below 1 mg/1.

Engineering data was also given for designing optimal water hyacinth and
duckweed sewage treatment systems to achieve secondary and possibly tertiary
treatment quality in small communities.
                .
B. C. Wolverton, Ph.D.
4/28/80
                                      177

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     ENGINEERING DESIGN DATA FOR SMALL VASCULAR AQUATIC
     PLANT WASTEWATER TREATMENT SYSTEMS
     B. C. Wolverton, National Space Technology Laboratories, ERL, NASA,
      NSTL Station, Mississippi  39529
     A general background of the research findings of the National Aero-
nautics and Space Administration's Vascular Aquatic Plant Program using
higher plants such as the water hyacinth (zichhornia crassipjs) and duck-
weed (Lemna sp. and Spirodela sp.) to treat domestic wastewater is pre-
sented.  New data on a small two cell lagoon system using only duckweed
is included.  Further laboratory experiments were conducted to correlate
BOD5 removal with known wet masses of water hyacinths.  The data from
these experiments with domestic wastewater indicates that an average
total BOD5 removal rate of 4.0 mg BOD5/gram WW (wet weight) could be
achieved with a seven day retention time.  When a phenol solution is sub-
stituted for the wastewater, the average total BOD5 removal is 3.5 mg
BOD5/gram WW (wet weight) in seven days.  This data along with the re-
sults of the previous field experiments is used to develop design crite-
ria for small domestic wastewater treatment systems servicing a maximum
of 3,000 people.  The criteria for these systems addresses the problems
of BOD5  reduction, total suspended solids reduction, odor control, and
sludge accumulation.
INTRODUCTION

     In the United States, wastewater lagoons are the most popular and
inexpensive method of treating domestic wastewater in small communities.
Thousands of these lagoons exist throughout the United States for treat-
ing domestic sewage and various type animal and industrial wastewaters.
Wastewater treatment lagoons vary from single to multiple celled systems.
Some of the earlier sewage lagoons were improperly designed and construc-
ted causing short circuiting, reducing the effective detention time and
contributing to high BOD and suspended solids in the lagoon effluent.
Today sufficient information is available to provide a basis for rational
design and construction of wastewater treatment lagoons.  For in depth
information on wastewater treatment lagoons see Gloyna,* Middlebrooks2
and Oswald. ' "*  Lagoon systems constructed in recent years are usually
effective in BOD reduction; however, excess algae can still cause high
suspended solids in the lagoon effluent during warm, summer months.
                                       179

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     NASA at the National Space Technology Laboratories  (NSTL) has been
using higher plants  for  five years to upgrade wastewater treatment la-
goons and treat chemical wastewaters.5'6'7  NSTL has also been conducting
studies directed toward  using higher plants to recycle waste in future
space stations.  The controlled use of  higher plants such as water hya-
cinths (Eiahhornia orassipes) and duckweeds (Spirodela sp., Lemria sp. and
Wolffia sp.) in conjunction with waste  stabilization ponds not only in-
creased the BOD removal  capacity of these systems, but also reduced the
high total suspended solids normally associated with sewage lagoons.
Higher plants reduce suspended solids in lagoon effluents by reducing al-
gae which make up a  large portion of the suspended solids.  Nitrogen,
phosphorus, potassium, sulfur, calcium  and other minerals can be removed
from domestic sewage by harvesting the  plant biomass.  This harvested
plant material is also a potential source of energy, fertilizer, feed,
food and other products.
     One important question about the design of vascular aquatic plant
waste treatment systems  that has not fully been determined or fully
understood yet is the BOD removal rate  that can be expected for this type
system.  The experiments in this report were designed to address this
unknown and achieve reproducible and quantitative answers to this ques-
tion.  Results of these experiments and previous field studies were com-
bined to develop design parameters for  energy-efficient waste treatment
systems for small communities using vascular aquatic plants.

BACKGROUND

     In addition to upgrading all wastewater treatment systems at NSTL
using water hyacinths and duckweeds, NASA has conducted several field
studies with local communities in South Mississippi directed toward im-
proving their lagoon systems using higher plants.  Systems described here
will include two single cell lagoons, one at NSTL and one at Lucedale,
Mississippi, and two multi-cell lagoons at Orange Grove and Cedar Lake
developments at Gulfport and Biloxi, Mississippi, respectively.
     The single cell lagoon at NSTL has a surface area of 2 hectares and
an average depth of 1.22 meters.  The average flow rate of 475 m3/day
resulted in a detention time of approximately 54 days.  The 6005 loading
rate in this lagoon averages 26 kg/ha/day, which constitutes a relatively
light load.   Before water hyacinths were added to this lagoon, the raw
sewage entering at the center of the system averaged 91 mg/1 BOD^ and
70 mg/1 total suspended solids (TSS) with effluent averages of 17 mg/1
BOD5 and 49 mg/1 TSS.  Concentrations of BOD5 and TSS during a 14 month
water hyacinth covered study period were:  influent 6005 110 mg/1 and TSS
97 mg/1,  and effluent 8005 7.4 mg/1 and TSS 10 mg/1.6  Plants harvested
from this lagoon contained 2.73% kjeldahl nitrogen and 0.45% total phos-
phorus (dry plant weight).
     A single cell facultative lagoon located at Lucedale, Mississippi
was studied extensively with and without water hyacinth coverage.8  This
lagoon has a surface area of 3.6 hectares (9 acres) and an average depth
of 1.73 meters.  Lagoon effluent flow rates during 100% water hyacinth
coverage averaged 935 m3/day.  The BOD5 loading rate was 44 kg/hectare/
day.  Before water hyacinths were added to this lagoon, the raw sewage
entering averaged 127 mg/1 8005 and 140 mg/1 TSS with effluent averages
of 57 mg/1 BOD5 and 77 mg/1 TSS.  Concentrations of BOD5 and TSS during
                               180

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the study period with complete plant coverage were:  influent, 161 mg/1
BOD5 and 125 mg/1 TSS; effluent, 23 mg/1 BOD5 and 6 mg/1 TSS.  With com-
plete water hyacinth coverage this lagoon was almost entirely anaerobic
with only traces of dissolved oxygen near the surface in the plant root
zone.  This condition produced odors at night when the plants were not
photosynthesizing.  The BOD5 loading rate of 44 kg/hectare/day produced
odors at night from this lagoon; whereas, a loading rate of 26 kg/hectare/
day in the NSTL lagoon produced a relatively odor free system when cov-
ered with water hyacinths.  Plants harvested from this system contained
3.56% kjeldahl nitrogen and 0.89% total phosphorus (dry plant weight).
     A complex lagoon system at Orange Grove, Mississippi was used for
conducting a 12 month study with water hyacinths in effluent from aerated
lagoons.9  This system consisted of two large aerated lagoons followed by
three parallel unaerated lagoons.  The flow rate into the water hyacinth
covered lagoon averaged 1000 m-Vday.  This lagoon had a surface area of
0.28 hectare and an average depth of 1.83 m.  The flow rate resulted in
an average detention time of 6.8 days.  The 6005 of the influent enter-
ing this lagoon averaged 50 mg/1 with an annual effluent average of 14
mg/1.  The total suspended solids entering averaged 49 mg/1 with an ef-
fluent average of  15 mg/1.  A parallel, control lagoon without water hya-
cinth demonstrated effluent concentrations of 37 mg/1 BOD5 and 53 mg/1
TSS.  Freezing temperatures occurred during this 12 month study period
killing the tops of the plants, and the decay of this large amount of
biomass elevated the BOD^ and TSS levels in the effluent during the
months of January, February, and March.  However, the water hyacinth cov-
ered lagoon still maintained the low effluent 6005 and TSS averages well
below the permit levels of 30 mg/1 each.  Because of the 1.83 m (6 ft)
depth, the dissolved oxygen averaged 2.0 mg/1 in the effluent but was
increased to 5 mg/1 following a 0.91 m  (3 ft) drop to a drainage ditch.
Plants harvested from this system contained a 3.74% kjeldahl nitrogen  and
0.85% total phosphorus  (dry plant weight).  Evapotransporation rates can
be expected to reach as high as 40% of the total influent volumes per  day
during hot summer months.  This characteristic was not considered in the
interpretation of  these field studies; therefore,  the effluent 8005 and
TSS concentrations should be up to 40% less during the summer months.
     A fourth system which is still being studied  is a two cell lagoon
system located at  Cedar Lake development in North  Biloxi, Mississippi.
This system shown  in Figure  1 has been in operation for 9 years.  It has
been receiving its present load of approximately 49.2 m^/day  (13,000 gal/
day) from 51 homes for  7 years.  This system was designed as  a conven-
tional, two cell lagoon with aeration in the first cell.  The first cell
has a surface area of approximately 0.08 hectare  (0.20 acre) and an
average depth of  2.4 m  (8  ft).  The average  flow rate of 49.2 in  /day
results in a detention  time of  approximately 36 days.  The BOD^ loading
in this lagoon is  approximately  128 kg/ha/day  (114 Ib/ac/day).  The
second cell has  a  surface area  of 0.07 hectare  (0.18 acre) and an aver-
age depth of  1.5 m (5 ft) with  a detention  time of approximately  22 days.
Four years ago duckweed coverage of the  second, unaerated cell occurred
through natural  means,  and NSTL started  monitoring this system in April
1979.  Prior to  this  date monitoring had not been  conducted;  therefore,
background data  without duckweeds is not available at this time.  In May
approximately 50%  of  the  duckweed coverage was  removed  for the first
time in four years.  The  5 hp surface aerator in the first cell was re-
duced to operating only at night.   From  May  to  December  1979  (see Table  1)
                                       181

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                 HP/FLOATING AERATOR
                 USED ONLY AT NIGHT
              ALGAE-
             SURFACE
            DUCKWEED
               COVER
.08 ha surface  (.20 acre),

2.4 m deep  (8 ft)
.07 ha surface (0.18 acre),

1.5m deep (5 ft)
       ANAEROBIC EFFLUENT
                 L .91 m drop  (3 ft)

             AEROBIC
Figure 1. Sewage Lagoons Serving Approximately 200 People—Cedar Lake
        Development Biloxi, Miss.
                          182

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                 Table 1. Monthly Average Data of TSS and  BOD   for  Duckweed Lagoon System Located
                          at Cedar Grove Development in Biloxi,  Mississippi.
Month, 1979
May
June
July
August
September
October
November
TSS, mg/1
Aerated Lagoon
Influent
178
194
420
271
233
173
142
Effluent*
397
176
108
113
132
96
61
Duckweed Lagoon
Effluent
10
9
16
8
22
19
11
BOD5, mg/1
Aerated Lagoon
Influent
200
203
138
160
173
171
290
Effluent*
64
67
34
13
20
15
29
Duckweek Lagoon
Effluent
20
28
13
10
17
8
10
00
CO
          * Also Influent to Duckweed Lagoon

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the raw sewage entering the aerated cell averaged 191 mg/1 BOD5 and 230
mg/1 TSS.  Average influent and effluent concentrations of 8005 and TSS
of the second duckweed-covered cell were:  influent, 35 mg/1 BODj; efflu-
ent 15 mg/1 BOD5; influent, 155 mg/1 TSS; effluent, 14 mg/1 TSS.  The
duckweed coverage on the second cell averaged 2 cm in depth producing an
odor free anaerobic system 24 hours a day.  The effluent dissolved oxygen
concentration was 0.5 mg/1 leaving the lagoon, but increased to 5 mg/1
after dropping 0.91 m  (3 ft) to a drainage ditch.

REMOVAL OF BIOCHEMICAL OXYGEN DEMANDING  (BOD)
 SUBSTANCES BY HIGHER PLANTS

     From field studies' data where water hyacinths were grown in domes-
tic sewage lagoons, one can readily see  that an additional reduction in
BOD is taking place that can be attributed to the plants.6'8  Because of
the nature of most sewage lagoons with their long detention times and
complex microbial make-up, controlled laboratory studies are desirable on
BOD removal rate to obtain more exact quantitative data.  Laboratory
studies were conducted at NSTL under wide spectrum growth lights with 14
hour photoperiods in an effort to obtain more exact BOD data.  Phenol, an
organic chemical, was also used in these studies to further demonstrate
the ability of water hyacinths to absorb, metabolize and remove BOD in a
similar manner to microorganisms.  Domestic wastewater consists of a com-
plex mixture of chemicals including phenol and related organics.  The ini-
tial volumes of raw sewage or phenol solutions were varied in order to
vary the depth and surface to volume ratio.  Some containers were left
free of water hyacinths as controls to determine the bacterial contribu-
tion to BOD removal.  In order to assure the same type of bacteria would
be present in the controls that were associated with the water hyacinth
roots, the plant roots were first dipped in all control solutions for
bacterial seeding.  Total bacterial counts and 5-day biochemical oxygen
demands (6005) were analyzed according to Standard Methods.10
     Results of these experiments are shown in Tables 2-4.  This data in-
dicates that the water hyacinth alone can be expected to reduce BOD5 of
domestic sewage by an average of 1.5 mg 6005 per gram of plant mass (wet
weight) with liquid detention times of 6 to 7 days.  Water hyacinths and
microorganisms together can be expected to remove an average of 4.0 mg
BOD5/gram plant mass (WW) with the same detention times.
     The ability of water hyacinths to remove 8005 produced by other sub-
stances such as phenol is demonstrated in Table 4.  This data indicates
that water hyacinths and microorganisms can remove 3.5 mg BOD5/gram plant
mass (WW) from aqueous solutions in 7 days containing 100 mg/1 phenol.
The BOD^ removal due entirely to the water hyacinth was 1.4 mg BOD5/gram
plant mass (WW).  These values are consistent with those found with do-
mestic sewage.
     These BOD removal rates were achieved with daily growth rates of 3-
4%; whereas, field studies have shown average daily growth rates as high
as 6% when water hyacinths were grown in sewage lagoons in South Missis-
sippi.12  The BOD and suspended solids removal rates are not entirely de-
pendent on growth and harvesting rates; whereas the removal of nutrients
such as nitrogen and phosphorus is dependent on these variables.  The BOD
removal rate is dependent on root absorption and metabolic functions; the
suspended solids reduction appears to be associated with algae elimina-
                               184

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                                Table 2. 5-day Biochemical Oxygen Demand (BOD ) and Bacteria Concentrations

                                         in Raw Sewage With and Without (Control) Water Hyacinths.
Experiment
1. w/WHs
2. Control
3. Control
4. w/WHs
5. w/WHs
6. Control
Fresh
Mass
WHS.g
1,860
0
0
2,140
2,000
0
Total BOD mg/1
o
Initial
60
60
60
180
180
180
3rd Day
	
48
36
100
6th Day
5
24
35
9
7
65
mg BODj. removed/
o
6 days
4,070
2,664
1,850
12,664
12,802
8,510
mg BOD removed/
g WHs
(6 day exposure)
2.2
5.9
6.4
Bacteria, count/100 ml
Initial
8.0 x 10
8.0 x 105
8.0 x 105
7. 7 x 105
7. 7 x 105
7. 7 x 10
3rd Day
	
1.0 x 104
6. 5 x 104
3. 6 x 104
6th Day
3. 0 x 104
3. 1 x 104
2. 3 x 10
1.0 x 104
5. 0 x 103
4
1.4 x 10
00
en
    Conditions:  Mean Atmospheric Temperature:  22°C


                Volume of Raw Sewage: 74 1


                Depth: 61 cm

-------
00
                               Table 3.  5-day Biochemical Oxygen Demand  (BOD ) And  Bacteria  Concentrations
                                         in Raw Sewage With and  Without  (Control) Water Hyacinths.
Experiment
1. w/WHs
2. w/WHs
3. w/WHs
4. Control
5. w/WHs
G. w/WHs
7. w/WHs
8. Control
9. Control
10. Control
Fresh
Mass
WHS.g
506
429
413
0
376
412
386
0
0
0
Total BOD. mg/1
3
Initial
190
190
190
190
112
112
112
112
112
112
4th Day
36
40
38
170
*50
46
42
76
69
60
7th Day
20
20
21
85
**21
18
22
48
60
48
mg BOD removed/
7 days
2040
2040
2030
1260
**1090
1130
1080
768
624
768
mg BOD. removed/
K-lVHs
(7 day exposure)
4.0
4.7
4.8
	
**2.9
2.7
2.8
	
	
	
Bacteria, Count/ 100 ml
Initial
TNTC
TNTC
TNTC
TNTC
6
7.0 x 10
7.0 x 10
6
7.0 x 10
7.0 x 106
7.0 x 106
7.0 x 106
4th Day
1.0 x 10°
3.0 x 10°
1.0 x 10J
1.0 x 10°
*3.3 x 106
4.3 x 106
6
2. 7 x 10
*** TNTC
/?
3.1 x 10
2. 2 x 106
7th Day
38 x 10°
231 x 10°
208 x 10°
44 x 10°
6
**2. 5 x 10
2. 7 x 104
1.2 x 105
4. 5x 105
3.1 x 106
3.6 x 10
               * 3rd day for experiments 5-10

              ** 6th day for experiments 5-10

             *** TNTC - Too numerous to count

               Conditions: Mean Atmospheric Temperature: 29°C

                         Volume of Raw Sewage:  12 1

                         Depth:  15 cm

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                      Table 4.  5-day Biochemical Oxygen Demand  (BOD  )  and  Bacteria Concentrations in
                               100 mg/1 Phenol Solutions With and Without  (Control)  Water Hyacinths
Experiment
1. Control
2. Control
3. Control
4. w/WHs
5. w/WHs
6. w/WHs
7. Control
8. Control
9. Control
10. w/WHs
11. w/WHs
12. w/WHs
Fresh
Mass
WHs.g
0
0
0
155
200
298
0
0
0
120
242
293
Total BOD , mg/1
«D
Initial
160
160
160
160
160
160
235
235
235
235
235
235
7th Day
114
120
115
35
37
35
136
115
116
26
15
29
mg BOD
o
removed/7 days
184
160
180
500
492
500
396
480
476
836
880
824
mg BOD^ removed/
g%Hs
(7 day exposure)
	 	
	
	
3.2
2.5
1.8
	
	
	
7.0
3.6
2.8
Bacteria, Count/100 ml
Initial
106 x 105
148 x 105
5
115 x 10
110 x 105
37 x 105
143 x 10'
3 x 104
4
1 x 10
2 x 104
1 x 104
1 x 104
1 x 104
7th Day
250 x 104
51 x 104
174 x 10
61 x 10
82 x 104
24 x 10
34 x 105
TNTC
__.—
60 x 106
3 x 105
TNTC
00
            Conditions: Mean Atmospheric Temperature:  29°C

                       Volume of Phenol Solution: 4 1

                       Depth:  13 cm

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tion prior to discharge.

DESIGN PROPOSAL FOR DOMESTIC WASTEWATER TREATMENT
 SYSTEMS USING HIGHER PLANTS

     Field and laboratory data collected during the past five years at
NSTL indicate that a combination of conventional sewage technology and
the controlled growth of higher plants such as the water hyacinth and
duckweed can produce cost effective, advanced wastewater treatment sys-
tems in warm to moderate climate zones.  Proposed designs for sewage la-
goons using water hyacinths and duckweeds to treat domestic wastewater
for small communities of 500 people or less is shown in Figure 2.  The
same type system for treating wastewater for communities of 1000 to 3000
people is shown in Figure 3.  In arriving at the following proposed de-
sign characteristics, four problems had to be addressed:  (1) sludge ac-
cumulation, (2) odor control, (3) BOD reduction, and (4) total suspended
solids removal.  Nitrogen and phosphorus removal must also be considered
if tertiary treatment is required.
     In order to minimize sludge handling problems, deep lagoons approxi-
mately 3 m (10 ft) in depth, with small surface areas appear to be the
most practical method for initial treatment and sludge collection.  Deep
lagoons receiving raw sewage have advantages and disadvantages.  These
lagoons act as anaerobic digesters, producing foul odors due to the lib-
eration of hydrogen sulfide gas during the sewage digestion process.
Approximately 114g (0.25 Ib) of slude per person is generated daily in
domestic sewage.  The total settled solids in sewage can be reduced by
40-50% and given off as gases if the sludge is anaerobically digested.11
Yearly sludge accumulation per person after anaerobic digestion is ap-
proximately 23 kg (51 Ibs).   The proposed design in Figure 2 should allow
approximately 100 years of operation with 500 people before presenting a
sludge removal problem.  The design in Figure 3 should operate for ap-
proximately 30 years with 3,000 people before sludge removal is needed.
Anaerobic digestion for the initial treatment of raw sewage not only
reduces the sludge solids, but also reduces the complexity of BOD sub-
stances and the concentration of toxic heavy metals when present.  Sul-
fides produced during anaerobic digestion will react with soluble heavy
metal ions to form a metallic sulfide precipitate that is relatively in-
soluble at pH near 7.0.  Approximately 1.8 to 2.0 mg of heavy metals can
be precipitated as metal sulfides by 1.0 mg of sulfide (S ).l
     In order to eliminate odor emission when anaerobic treatment is
used in the first step, it is essential for the first lagoon to contain
a photosynthetic aerobic zone, mechanically aerated surface zone, sur-
face sealer,  or a combination of these features.  The most reliable
means of assuring an aerobic surface zone for odor control appears to be
the limited use of surface aerators.  Studies in Mississippi with the
system depicted in Figure 1  have shown that the use of surface aerators
during dark hours and photosynthetic algae during daylight hours effec-
tively controls odors with minimum aeration cost.   A limited amount of
research has  been conducted  by NASA on the use of duckweed as a photo-
synthetic surface sealer for small anaerobic lagoons.  The use of duck-
weeds would eliminate the energy requirements of supplemental mechanical
aeration.  BOD^ reductions in excess of 70% at hydraulic detention
times of 1.2  days in anaerobic ponds was noted by Oswald et al.^  Deten-
tion periods  of up to 5 days were recommended to compensate for
                               188

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                         •£5  HP FLOATING  AERATORS
ALGAE- \
SURFACE \
jfc ^f ] 1.24 ha surface (0.5 acre),
/ 3.05 m deep (10 ft)
^r^
W- ,nr, n / f r^r\ e^\
T
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-------
                                    *S HP/FLOATING
                                         AERATOR
                                     NIGHT USE ONLY
     DUCKWEED
      COVERED
       1-2  CM
               Anearobic Ponds
             are .09 ha  (0.25 acre)
            and 3.05 m deep (10 ft)
       WATER
     HYACINTHS
    19.14 m (30 f
          I
      EFFLUENT
  ALGAE-
  SURFACE
                  o
                  o
                  IT)
  WATER
HYACINTHS
                           Clarification
                           Ponds are
                           .91  m deep
                             (3 ft)
 EFFLUENT
     ALGAE-
    SURFACE
  DUCKWEEDS
REQUIRE RIP-RAP
FOR  REAERATION
  OF EFFLUENT.
Figure 2. Water Hyacinth,  Duckweed and a Combination Water Hyacinth-Duckweed
         Sewage Treatment Systems Which Achieves Secondary to Tertiary Treat-
         ment for Wastewater from 250-500 People.
                               190

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decreased bacterial activity during cold weather.  Detention times of 15
and 5 days are proposed for the anaerobic lagoons in Figure 2 and 3 re-
spectively.  When surface aerators are used, additional BOD removal at
the rate of 24 kg/ha/day can be achieved.
     The designs shown in Figures 2 and 3 are based on influent waste-
water containing 150 mg/1 6005.  These designs assume a 50% BOD^ removal
in the first anaerobic lagoon.  Water hyacinth covered lagoons can be
expected to remove approximately 1045 kg  BOD^/hectare every  seven  days  or
148 kg BOD5/hectare/day based on the results of the experiments and field
data presented in this paper and an average standing crop of 220 mt/hec-
tare (100 ton/ac).
     If tertiary standards must be met, the total nitrogen and phosphorus
must be reduced to 3 and 1 mg/1, respectively.  Assuming a sewage influ-
ent containing 35 mg/1 kjeldahl nitrogen and 7 mg/1 total phosphorus with
a daily increase and harvest rate of 5% plant mass, then the design in
Figure 2 should achieve tertiary treatment levels for the waste of 250
people and Figure 3 for 1500 people.  This is assuming a standing crop of
220 mt/hectares and a 0.91m (3 ft) depth in the elongated water hyacinth
lagoons shown in Figures 2 and 3.  Total suspended solid concentrations
are reduced by water hyacinth coverage due to shading effects and pos-
sibly nutrient reduction.
     Plant material harvested from this type system can be processed into
usabTe products.  Studies at NASA have shown that the simplest product
produced from water hyacinths is compost, a complete plant growth media
produced by aerobic decomposition.  Plants such as cucumbers, squash,
corn, tomatoes, peas, sorghum, etc., have been grown successfully using
decomposing water hyacinths as the sole source of soil and food.
     Another potential product from the harvested biomass is methane.
Methane is produced by anaerobically digesting the fresh plant material.
Current experiments at NSTL demonstrate that 0.18 m-^ (6.3 ft^) of methane
can be produced per dry kilogram of plant material in 24 days or less
digestion  time at 37°C.
     An engineering handbook  on the construction of vascular aquatic
plant wastewater treatment systems will be available by January  1980.
                                       191

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                                 REFERENCES

 1.  Gloyna, E.F., J. F. Malina, Jr. and E. M. Davis.  Ponds as a Waste-
     water Treatment Alternative.  Water Resources Symposium Number Nine.
     Center for Research in Water Resources, College of Eng., Univ. of
     Texas at Austin (1976).

 2.  Middlebrooks, E. J., N. B. Jones, J. H. Reynolds, M. F. Torpy and
     R. P. Bishop.  Lagoon Information Source Book, Ann Arbor Science
     Publishers, Inc.,  Ann Arbor, Michigan (1979).

 3.  Oswald, W. J., C.  G. Golueke and R. W. Tyler.  "Integrated Pond Sys-
     tems for Subdivisions," Journal Water Pollution Control Federation.
     ^39 (8), 1289 (1967).                                           ~~

 4.  Oswald, W. J.  "Waste Stabilization Lagoons," Proceedings of a Sym-
     posium at Kansas City, MO.  33-40 (1960).

 5.  Wolverton, B. C. and Rebecca McDonald.  The Water Hyacinth:  From
     Prolific Pest to Potential Provider, AMBIO. 8^ (1), 1-9 (1979).

 6.  Wolverton, B. C. and Rebecca McDonald.  Upgrading Facultative Waste-
     Water lagoons with Vascular Aquatic Plants.  Journal Water Pollution
     Control Federation, 5J, (2), 305-313 (1979).

 7.  Wolverton, B. C. and Rebecca McDonald.  Wastewater Treatment Utiliz-
     ing Water Hyacinths.  Proceedings of the 1977 Natl. Conf. on Treat-
     ment and Disposal  of Ind.  Wastewater and Residue.  Univ.  Houston,
     Texas,  205-208 (1977).

 8.  Rebecca C. McDonald.  A Comparative Study of a Domestic Wastewater
     Lagoon With and Without Water Hyacinths.  NASA Tech. Memorandum.
     TM-X-72735 (1979).

 9.  Wolverton, B. C. and Rebecca McDonald.  Water Hyacinths for Upgrad-
     ing Sewage Lagoons to Meet Advanced Wastewater Treatment Standards:
     Part II.   NASA Tech. Memorandum TM-X-72730 (1976).

10.  Standard Methods for the Examination of_ Water and Wasjijwater.   14th
     Ed. American Public Health Association, Washington, D.C.  (1975).

11.  Metcalf & Eddy, Inc.  Wastewater Engineering:  Collection, Treat-
     ment ,  Disposal. McGraw-Hill Book Co.  (1972).

12.  Wolverton, B. C. and Rebecca McDonald.  Water Hyacinth Productivity
     and Harvesting Studies.  NASA/ERL Report No. 171, NSTL Station,
     MS 39529 (1978).
                               192

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     DEVELOPMENT OF HYACINTH WASTEWATER TREATMENT
     SYSTEMS IN TEXAS

     Ray Dinges, Texas Department of Health, 110 West 49th Street,
       Austin, TX  78756
INTRODUCTION

     Field observations revealed that turbid, enriched waters (municipal
wastes, cannery wastes, and sugar refinery wastes) were clarified and
stabilized after passage through natural water areas covered by water
hyacinth (Eichhornia crassipes (Mart.) Solms).  Staff of the Wastewater
Technology and Surveillance Division began to speculate on the possi-
bility of utilizing controlled hyacinth culture for improving stabili-
zation pond effluent.  Other possible uses of hyacinth culture envi-
sioned included the clarification of turbid river waters used as do-
mestic water supply sources and the demineralization of brackish ground
waters.

     Simple, solar-powered stabilization ponds have a number of positive
advantages, including the reduction of adverse chemical and biological
agents (Dinges, 1979).  A decided disadvantage is that their effluents
are filled with single-celled algae, nutrients, and excessive levels of
fecal organisms (Dinges and Rust, 1970).  Several hundred stabilization
pond systems are used in Texas for treating municipal, industrial and
agricultural wastewaters.  Many pond systems discharge to small streams
and to watercourses with intermittent flow.  Some of these waterways
enter reservoirs utilized as sources for domestic water supply and for
recreation.  Sludge banks and foul, stagnant pools of water are not at
all uncommon below the discharges of stabilization ponds.  Smallhorst
(1963) expressed the need for research to improve stabilization pond
effluent quality by biological means.

     Preliminary observations on hyacinths grown  in wastewaters were
commenced in 1970.  A basin was constructed at a  private residence in
Dale, Texas for that purpose.  The basin was about 2-m in width, 9-m in
length, and operated at a a depth of 1-m.  Septic tank effluent was
diverted into  the basin and the desired water level maintained by
periodic addition of well water.  Plants grew well in the diluted
septic tank effluent and waters at the lower end  of the basin remained
clear.
                                      193

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 Field  Study

     An opportunity was afforded  to evaluate the effect of hyacinths on
 water  quality  in  1972.  The City  of Gregory, Texas is served by an
 overloaded wastewater  treatment facility.  Plant effluent discharges
 into a drainage ditch  which empties into a 1.2-ha impoundment (Butterfly
 Lake).  Overflow  from  Butterfly Lake goes into Corpus Christ! Bay.  The
 ditch  and the  lake have been covered by hyacinths for years.

     Hyacinths were sprayed with  broadleaf herbicide on two occasions in
 November, 1972.   A field  study was conducted from July through October,
 1973 to determine water quality changes during regrowth of the plants
 (Dinges, 1973-1976).   Water overflow from Butterfly Lake at that time
 was of good quality and contained 2 mg/1 BOD^ and 10 mg/1 of total
 suspended solids.  The unplanned  hyacinth wastewater treatment system at
 Gregory is still  functioning.  Primary study emphasis was not directed
 towards organic quality improvement, but upon the capability of hyacinths
 to demineralize water.  Water samples for chemical anaylsis were collected
 weekly from a  650-m section of the ditch having an estimated detention
 time of about  8 days.  Results indicated a mean reduction in total
 dissolved solids  of 59.3%.  A portion of the observed decrease may
 possibly be attributed to ion exchange mechanisms associated with the
 peaty  organic deposits present in the ditch.

 Pilot  Studies

     Facilities.  The  City of Austin was approached and agreed to
 provide a pilot scale  experimental hyacinth culture basin at the Williamson
 Creek  wastewater  treatment facility in November, 1974.   The pilot unit
 was completed in April, 1975.  See Figures 1 and 2.

     Two wastewater treatment plants are located at the Williamson Creek
 facility.   Plant A consists of an aerated basin equipped with a surface
 aerator, a clarifier and  three stabilizaiton ponds.   Sludge is returned
 to the aerated basin with excess sludge and clarified effluent being
 discharged to the ponds.  The three ponds,  which are about 1.2-ha in
 size,  are operated in  series and at a depth of about 2.44-m.  There is
 no discharge from the  system and excess water is pumped to a large pond
 of Plant B by an electric driven pump rated at 31.54-1/sec that is
activated by a float switch.  Design capacity of Plant  A is 757-m^-d and
 it receives controlled flows of 1,325 to 1,438-m 'd.

     Plant B receives  the remainder of daily flow,  which averages 12,500-
m -d.   This plant consists of two aerated basins operated in parallel
and three stabilization ponds.   The three ponds are  18.2-ha, 15.4-ha and
 13.0-ha in size and are 2.7-m deep.
                                                  2
     An excavation 9.1-m wide and 64-m long (585-m )  was constructed
between Pond 3 of Plant A and Pond 1 of Plant B and  divided into four
 sections by barriers of crushed stone 10 to 15-cm in diameter.   Section 1
was 30.5-m in length and 0.6-m in depth.   One half  of the second
 section, which was 18.3-m long,  was 0.6-m deep,  and  the other half was
 3-m deep.   Both of the remaining sections were 7.6-m long and 0.8-m
deep.
                               194

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Fig. 1  Austin, Texas-Williamson Creek Experimental
      Hyacinth Treatment Pilot System, 1975.
                (Courtesy of S. Hart)
                                  195

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                                   FIG,  2  CITY  OF  AUSTIN,  TEXAS

                                      WILLIAMSON  CREEK  EXPERIMENTAL

                                HYACINTH WASTEMTER  TREATMENT  FACILITIES
                      PLANT
CD
T B Tj
POND 1 /
/
-HA /
y/
f i




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1
/PlLO-ft
'H.M
(ABANDONED







J* *
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\
I
1
*
\
VAC I NT
CULTURE
BASIN
H2-HA
1
\
4
\
i
i
i






i








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STAB,
POND 2
1,2-HA






















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o

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STAB,
DOND 1
1,2-HA




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                                                                                 AERATED
                                                                                  BASIN
                                                                        INFLUENT

                                                                         PLANT A
2 Co'JTACTN
DTURE USE)
                                           ROCK
                                           BARRIER

-------
     During the first study phase (June 1975 to February 1976) ,  the
experimental system was furnished with water obtained from Pond  3 of
Plant A using an electrically-driven centrifugal pump rated at 3.15-
1/sec.  A 5-cra diameter steel pipe was used for water delivery.   A waste
line with a gate valve was provided to regulate inflow by discharging
excess water back to the stabilization pond.

     A more enriched water was acquired from Pond 1 (18.2-ha) of Plant B
in the second study phase, which extended from May through August, 1976.
Water was provided to the experimental facility by gravity flow through
a 6.4-cm diameter steel pipe equipped with a gate valve for flow control.

     A rectangular plastic (polyethylene) container 35.5-cm x 12.7-cm
was placed in each section to serve as a sedimentation pan.

     Mean water depth in the experimental system during the first study
phase was 1-m.  At a flow rate of 1.26-1/sec, theoretical system deten-
tion time was 5.3 days.  Operational mean water depth was maintained at
85-cm in the second study phase and the detention period was 4.5 days at
a flow rate of 1.26-1/sec.  A 1.26-1/sec rate of flow was found to be
about the maximum hydraulic loading that could be accpeted without
causing breakthrough of solids.  Flow introduced into the system amounted
to 109-m3-d, or the wastewater contribution of a community of about  300
people.

     Surface organic loading on the experimental system was  4.34  g/m -d
BOD  in the first study phase and 8.93 g/m  -d in the second  study phase.
Influent-effluent samples were collected weekly and analyzed by accepted
procedures.

     Results.  Extensive testing of system  influent-effluent revealed
that significant quality improvement in  stabilization pond effluent  was
obtained by hyacinth treatment.  Detailed  results of the  pilot  studies
have been reported upon previously  (Dinges, 1976).  A brief  summary
of selected water quality parameters evaluated are presented in Table 1.

     Approximately 50 percent of influent  phosphorus  (P)  and 80 percent
of potassium  (K) were removed in summer  months.  Leaching of P  and K
from the system occured during the winter.  The  standing  crop of
hyacinths at  the end of a growing season represented a  dry weight
biomass production of  3,184 gm/m  .  This  compares  favorably  to  the
similar measurement  (2,970 gm/m ) made by  Wooten and Dood (1976).  Mean
moisture content of  the plants was  94  percent and  they  had a mean ash
content of  19.6 percent.  Hyacinths accumulated  heavy metals, other
minerals,  and  trace  organics  from the  water during the  growing  season.
                                       197

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                  Table 1

Pilot Studies-Indicated Mean Reductions in
  Selected Wastewater Quality Parameters
      Affected by Hyacinth Treatment
            First Study Phase
         June 1975-February 1976
 Second Study Phase
May 1976-August 1976
     Influent Effluent  % Reduction  Influent Effluent  % Reduction
Chlorophyll a,
mg/1
BOD mg/1.
TSS, mg/1
COD, mg/1
MBAS, mg/1
TN, mg/1
TON, mg/1
Fecal Conform
Bacteria/lOOml

0.351
22.6
43.3
84
0.17
8.16
4.33

2895

0.028
5.2
7
40
0.03
2.47
1.25

31

93
77
84
52
82
69
71

98

0.35
46.5
117
184
0.13
9.94
7.59

27423

0.017
5.7
7.5
51
0.04
3.59
1.63

363

95
87
93
72
66
63
78

98
                      198

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     Pollutant Removal.  Waters of a basin completely covered by a
hyacinth mat are quite still, bave a pH near neutral, and are almost
totally shaded.  Temperature fluctuations are moderated and stratifi-
cation prevails during the summer.  Phytoplanktonic algae growth is
precluded due to light restriction and sedimentation is enhanced in the
stilled waters.  Coagulation of incoming £ilgae cells and heavy sludge
deposition occurs in the influent vicinity of the basin.  Surface basin
waters contain low levels of dissolved oxygen and bottom waters are
anoxic.  Free carbon dioxide levels are high.  Hyacinth roots serve as a
barrier to the horizontal movement of suspended solids.

     The hyacinth overstory; surface water; root area; free water beneath
the mat; and the basin bottom may be viex^ed as being biotic zones.  Most
biota reside in the surface and root zones.  Extensive biological activity
occurs in the influent region of a basin, resulting  in a veritable
"rain" of organic debris, much of which is not readily biodegradable.
Bacteria, fungi, predators, filter feeders, and detritovores are present
in large numbers.  The biological reduction, oxidation, and consumption
processes performed by the complex community of organisms in a hyacinth
culture basin serve to stabilize water by releasing  stored potential
energy.  Organic residues accumulate in the basin due  to the physical
processes of filtration and sedimentation.

     Hyacinths obtain  carbon dioxide from the air.   Otherwise, hyacinth
biomass is derived from soluble substances from the  wastewaters  in which
they are growing.  Plant uptake of materials from the  water  is restricted
to the period of active growth.  The overall improvement of waters
passing through a culture basin may be attributed to the removal of
suspended particulates fostered by the physio-chemical and biological
factors related to the habitat provided.  This fact  becomes  quite  clear
when waters exiting a  basin are of high quality even in  the  winter when
the hyacinths are frozen down  to  the water surface.

Plant  Scale Study

     Following  the successful  conclusion of  the pilot  studies, a full-
scale  facility  treating an amount of wastewater which  might  be expected
from a population of about 3,500  people was  provided and placed  into
operation.  See Figures 2 and  3.  The  experimental  hyacinth  culture
basin  is being  operated as if  it were  an integral unit of  the Williamson
Creek  wastewater treatment plant  in order  to learn  more  about operational-
management procedures.  Routine effluent quality evaluation  is restricted
to those parameters commonly  included  in discharge  permit  requirements.

     Facility.  The last  1.2-ha stabilization pond  of  Plant  A was  drained,
cleaned, and  converted into  a  hyacinth culture basin in October,  1977.
A crushed stone barrier approximately  2.4-m  in height  and  21-m x 21-m in
size was constructed  at  the  lower end  of  the basin  to  prevent  escape  of
the plants and  to create  a clear  outlet  zone.  Influent  is admitted  to
the basin  from the second  stabilization  pond by  an  adjustable  gate.
Water  depths  have been varied  from  0.7-m  to  1.3-m  in the hyacinth
culture basin.  System effluent is  transferred to   one of  the  nearby
stabilization ponds of Plant  B by an  electrically  driven pump  rated  at
31.5-1/sec.,  Flow  to  the  wastewater  treatment plant varies between 1,325
and 1,703 m  -d.  A somewhat  lesser  amount  of water  passes  through the
hyacinth basin  due to  seepage  and evaporation losses.   Test  results  from
October, 1977  until August,  1979  are  presented in  Table 2.

                                       199

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Fig. 3  Austin, Texas-Outlet Area of the Williamson
Creek Experimental Hyacinth Treatment System,  1979.


                    200

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                            Table  2

         Influent-Effluent  Quality -  Williamson  Creek
             Full-Scale  Hyacinth Treatment  System.
                  October 1977  - August 1979

                Influent       n        Effluent**       n     % Reduction
BOD , mg/1
TSS, mg/1
Fecal Coliform/
41.9
40
5388*
(40)
(41)
(28)
12
8.8
302
(41)
(42)
(31)
71
78
94
 * One test result of 10 x 10  organisms not used in calculation of mean
** Includes data collected during two winter periods when plants had
   been frozen and were in a state of decay.
                                 201

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      The culture  basin was  drained,  cleaned and planted with hyacinths
 in May,  1979.   Basin debris removed  was buried in  trenches at the plant
 site.

 Other Municipal Hyacinth  Treatment Systems

      All municipal hyacinth treatment  systems in Texas are considered to
 be experimental at the present  stage of process development.  Hyacinth
 treatment facilities are  being  monitored  to learn  more about system
 design,  operation, and management procedure.

      Austin-Hornsby  Bend  Sludge Treatment Ponds.   Excess activated
 sludge from  the Govalle and the Walnut Creek wastewater treatment plants
 is transferred  to the Hornsby Bend pond system by  force main.  The
 facility consists of a 34.4-ha  pond  followed by two other ponds 26.3-ha
 and 16-ha in size.   See figures 4 and  5.  The system receives about
 7,570  m  -d of excess activated  sludge.  A 1.4-ha hyacinth culture basin
 has been provided to treat  the  sludge  pond system  overflow.  The upper
 end of the rectangular culture  basin is quite shallow and deepens
 gradually towards the outlet.   Maximum water depth is about 2.46-m and
 the mean basin  depth is estimated to be 1.23-m.  A section near the
 outlet has been fenced to provide a  clear area and to serve as a chlorine
 contact  zone.   Chlorine is  introduced at the fence line through perforated
 plastic  tubing.   A 90 V-notch  weir  has been installed in the outlet
 drop box for flow measurement.  Hyacinths were planted in the basin in
 late May, 1979.   About 6,050 m  -d passes through the culture basin.
 Very little  change between  influent  and effluent quality is evident at
 this hydraulic  loading rate.

     San Juan-Rio Grande Valley Pollution Control  Authority.  San Juan
 has  a  population  of  about 6,800 persons.  Mean daily inflow to the
 wastewater treatment  plant  is 1,514  m  , with peak  flows being around
 3,785  m3.d.  Influent to the plant is usually septic.  The facility
 consists  of a 0.97-ha raw sewage pond provided with a surface aerator; a
 0.97-ha  stabilization pond; two hyacinth culture basins 1-ha each in
 size;  and a chlorine  contact chamber.  See Figures 6 and 7.  Mean
 organic  loading on the stabilization ponds is about 15.6 g/m -d of BOD
 or  four  times greater than  suggested in the Texas  "Design Criteria for"*'
 Sewerage  Systems."   For short periods during canning operations,  plant
 ponds may receive more than 30  times that amount of organic loading
which would be appropriate.  The surface aerator is to be enclosed
within a  small diked area within the raw sewage pond in the near  future
 in order  to increase oxygen transfer efficiency and treatment capability.
 System effluent quality from April,   1978 to March,  1979 is presented in
 Table  3.

     The  two hyacinth basins, which have been designated as A and B may
be operated at depths from 15-cm to 1.4-m.  Water  from the second
 stabilization pond is delivered to the basins through pipes equipped
with gate valves.   Culture basins receive variable flow rates as  there
 is little excess storage capacity in the feeder stabilization pond.
                              202

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 FIG,  4   CITY OF AUSTIN, TEXAS

HORNSBY BEND SLUDGE TREATMENT FACILITY
DROP
                             SLUDGE
 OUTFALL
          HYACINTH
           BASIN

           1,4-HA
        ARRIER
                            203

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Fig. 5  Austin, Texas-Hornsby Bend Hyacinth Treatment
                    System, 1979.
                     204

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             FIG, 6   RIO GRANDE VALLEY POLLUTION
                           CONTROL AUTHORITY
                            SAN JUAN,  TEXAS
                                               AERATOR
                                                     RAW
                                                     WASTEWATER
                        '.  DISTRIBUTOR
                                                 DISTRIBUTOR
            BARRIER^
                         1,0-HA
CONTACT
     EFFLUEN
              BARRIER
                                      HYACINTH BASIN A
1,0-HA
                                                BARRIER
                                                EFFLUENT
                                205

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Fig. 7  San Juan, Texas-Hyacinth Basin A, 1979.
          (Courtesy of H. Nordmeyer)
                            206

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                      Table 3

          San Juan Effluent Quality Data*
               April,  1978 - March,  1979

             Annual Mean   Maximum Recorded

BOD   mg/1        23              40
TSS, mg/1         24              54
*  One hyacinth unit in operation—Basin A.
                                207

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     Water  is distributed  to Basin A  through a  24.6-m length of plastic
 pipe having 5-cm diameter  openings at  3-m  intervals.  The basin outlet
 is located  opposite the distribution  pipe  at a  distance of 115-m.  In
 designing a culture basin,  it  should  be assumed that water will flow
 directly from the  inlet to the outlet.  Therefore, the "minimum effec-
 tive zone"  of Basin A  is only  0.13-ha.  It is planned to extend the
 distribution pipe  along the entire inlet side of the basin (95.3-m) at
 the time the unit  is drained for removal of hyacinths and basin debris.
 This will increase the effective zone  to 0.52-ha, or one-half of the
 total basin area.

     A wire screen is  located  a short  distance  in front of the outlet
 structure.  An additional  wire fence  creating a clear zone of about 185
 m  will be  installed in the future to  allow for reaeration of the water
 prior to discharge and prevent the discharge of debris drawn from
 beneath the mat by outflow velocity.   An open water area around the
 outlet is especially important in the  Rio Grande Valley where the
 natural waters contain elevated sulphate levels.

     The San Juan  hyacinth wastewater  treatment system is being tested
 in cooperation with the Rio Grande Pollution Control Authority.  Basin A
 has been operated  at various depths and flow rates since July, 1978.
 Water samples are  collected by personnel of the Rio Grande Valley
 Pollution Control  Authority, refrigerated, and  forwarded to the Depart-
 ment central laboratories  for  analysis.  Test results are presented in
 Table 4.

     Alamo-Rio Grande  Valley Water Pollution Control Authority.  Alamo
 has a population of about  5,500 persons.  Mean  daily inflow to the,.
 wastewater  treatment plant  is  1,514 m  , with peak flows of 3,785 m .
 The plant facility consists of an Imhoff tank;  a trickling filter; an
 aerated basin equipped with a  surface  aerator (2,838 m  capacity); two
 4.04-ha stabilization  ponds operated in parallel; two hyacinth culture
 basins (1.35-ha and 1.05-ha);  and a chlorine contact tank.  See figures
 8 and 9.
                                                        o
     Domestic wastewater flow  is estimated to be 1,060 mj-d and is
 treated in  the Imhoff  tank  and trickling filter.  Cannery wastes and
 domestic effluent  are  introduced to the aerated basin.  One-half of the
 discharge from the aerated basin is diverted to each of the stabilization
 ponds, thence into the hyacinth culture basins.  Organic loading on the
 stabilization ponds is estimated to be about 4.6/m^-d of BOD,..  Hyacinth
 culture basins were recently completed and planted with hyacinths.
 Effluent quality of the system from April, 1978 through March, 1979
prior to the introduction of hyacinths averaged 33 mg/1 BOD  and 86 mg/1
TSS.   Monthly means of effluent BOD  and TSS were 38 and 68 mg/1 in May,
 1979 and 50 and 82 mg/1 in June.   The basins were partially covered by
hyacinths  during this period (<25%).

     San Benito.   San Benito has a population of about 17,500 persons.
Mean daily flow to the wastewater treatment facility is 2,460 m ,  with
 peak flows up to 6,737 tir^-d.  Plant influent is septic.   The treatment
 facility consists of a 7.86-ha raw sewage stabilization pond, followed
by four more stabilization ponds having a total surface area of 13-ha.
 The last pond has been divided into three sections by earthen dikes to
 serve as an experimental hyacinth treatment facility.   Basins 1 and 2
 are 0.8-ha each and Basin 3 is 2-ha in size.   The three basins are
designed to operate in series.   About one-half of Basin 2 was covered by
hyacinths and Basin 3 was completely covered with plants when the
 facility was inspected in June,. 1979.   See figures 10 and 11.

                                    208

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                                                          Table 4

                                  San Juan-Rio Grande Valley Pollution Control Authority
                                 Effluent Quality of Hyacinth Basin A at Various Loadings
                                                   and Operating Depths
o
CO
July, 1978 - May, 1979
n
1
4
7
10
Raw Sewage
BOD5, mg/1
90
86.2
265.7
319.4
TSS, mg/1
111
113.2
221.5
282
Basin A
BOD5, mg/1
20
9.2
35
31
Effluent
TSS, mg/1
30
<11.2
30.4
32.3
Depth, cm.
61
91
91
137
3
Flow, m
870
852
1552
1855
Total °
BOD
77.7
89.3
86.8
90.3
I Removed
TSS
72.9
90.1
86.2
88.5

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            FIG,  8  RIO GRANDE VALLEY

               POLLUTION CONTROL AUTHORITY

                      ALAMO,  TEXAS
                 IMHOFF
     DOMESTIC
    WASTEWATER
          AERATOR
           RASTN
               RICKLING
               FILTER
               CANNING
               WASTEWATER
            STAB,

           POND 1
            STAB,

            POND 2
                        DISTRIBUTOR
EFFLUENT-
    CL2 CONTACT
i
HYACINTH



X*X*~
                         DISTRIBUTOR
                            24,6-M
 HYACINTH BASIN A

 1,35-HA^
	y/^fr"^	
            EFFLUENT   BARRIER  EFFLUENT    BARRIER
                      210

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Fig. 9  Alamo, Texas-Distribution Pipe of Hyacinth Basin B.
                Basin A in Background, 1979.
               (Courtesy of H.  Nordmeyer)
                               211

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FIG,  10  CITY OF SAN BENITO, TEXAS
                                      RAW WASTEWAJER
v
                    212

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Fig. 11  San Benito,  Texas-Two of Three Hyacinth
                  Basins,  1979.
           (Courtesy of H. Nordmeyer)
                          213

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     A wire  fence barrier  is located a short distance in front of the
 outlet.  Changes in  the design and operation of the system are being
 considered.  Mean effluent quality from April, 1978 through March, 1979
 averaged 17  mg/1 BOD  and  35 mg/1 TSS.  The means of effluent BOD  and
 TSS were 17  and 20 mg/1 for June, 1979.                          5

     Rio Hondo.  Rio Hondo has a population of about 1,300 persons.
 A 0.8-ha raw sewage stabilization pond was constructed in 1950 to serve
 the city.  The pond became filled with sludge over the years.  Effluent
 quality from the pond had  deteriorated to the extent that it was compar-
 able to that of the raw wastewater.  Hyacinths were planted in the pond
 a few years  ago.  Pond effluent quality improved somewhat.  Sludge
 deposition was enhanced by the hyacinths and increased in depth until
 only a few centimeters of water remained in the pond.

     Three 0.41-ha hyacinth culture basins have been constructed.
 Basins 1 and 2 are rectangular and Basin 3 is square.  The raw sewage
 stabilization pond was bypassed and raw wastewater now discharges to
 Hyacinth Basin 1.  Basin 1 and 2 are connected by piping.  Water from
 Basin 2 is pumped to Basin 3, with a pump controlled by a float switch.
 Most of the  surface areas of the three basins are now covered by plants.
 See figure 12.
                                                 o
     Raw sewage flow to the system is about 454 m -d.  Hyacinth Basin 1
 has an organic loading estimated to be 19.7 g/m^-d of BOD,..  Total
 system surface area has an organic loading of 6.6 g/m -d of BOD,..
 Effluent quality from July, 1978 through May, 1979 was 16 mg/1 BODS and
 24 mg/1 TSS.  Monthly means of effluent BOD- and TSS were 10.5 and 6 mg/1
 in May and 14.5 and 12 mg/1 in June, 1979.

     The city plans to remove the sludge and restore the dikes of the
 raw sewage stabilization pond and place it back into operation.  Modifi-
 cations are  also to be made to improve distribution of water through the
 hyacinth culture basins.

 Design Considerations

     Hydraulic Loading.   Neuse (1976) conducted a study to define the
 hydraulic capability of a pilot hyacinth basin designed to remove
 suspended solids from stabilization pond effluent.  A pilot unit having
 a channel configuration and with a surface area of 18.58 m  was constructed
 at the Williamson Creek wastewater treatment plant in Austin, Texas.
 The plastic  lined channel had a width to length ratio of 12.5:1.
 Hydraulic loading rate on the system varied from 0.44 I/sec to 0.63 I/sec.
 Neuse concluded from his study that a second identical unit operated in
 series would be as efficient in solids removal as the first unit, but
 the amount of solids removed would be less.  He postulated that a
 culture basin could be sized properly for any given hydraulic loading
 rate and proposed a broad rectangular configuration (channel replication)
with even distribution of influent on one side and the discharge of
 effluent over an extended weir along the opposite side.
                               214

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FIG, 12  CITY OF RIO HONDO,  TEXAS
     RAW WASTEWATER
        HYACINTH
        BASIN A
        0,41-HA
HYACINTH
BASIN B
(Ml-HA
                             runr \
                           TRANSFERS
                    HYACINTH
                    BASIN C
                    (Ml-HA
RAW
WASTEWATER
STABILIZATION
POND
(FUTURE USE)
0,8-HA
                                    DUTLET
                                EFFLUENT
                                215

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     Operation of the Williamson Creek pilot hyacinth treatment system
had revealed that hydraulic loading is a foremost design consideration.
The basin produced low TSS levels at a sustained flow rate of 1.26 I/sec.
Increasing the flow to 1.89 I/sec resulted in solids breakthrough.  A
culture basin which is not hydraulically overloaded should consistently
produce <10 mg/1 BOD,, and TSS.  Organic loading on a basin should normally
be <10 g/m -d of BOD- when input is stabilization pond waters.

     When the pilot scale system was abandoned and allowed to dry out
after two years operation, it was noted that most sludge accumulation
had occurred in a semi-circle near the influent.  The dried sludge layer
was about 10-cm thick.  Drainage of the full-scale hyacinth system at
Williamson Creek for cleaning after two years of continuous operation
revealed a fan-shaped area in the influent vicinity with a sludge (wet)
depth of about 0.6-m.

     An elongated rectangle may be satisfactory in some instances, but
it is certainly not an efficient configuration for a hyacinth culture
basin.  The broad rectangular shape would be efficient, but the extended
discharge weir and the barrier required would be costly.  It is also
difficult to maintain the integrity of an extended weir.  It was sug-
gested by S.W. Hart, Chief, Engineer, Wastewater Technology and Surveil-
lance Division, that a triangular basin might be appropriate.  Influent
could be distributed over a broad front and an even flow throughout the
entire basin area would be assured.  However, triangular basins do not
represent efficient land use.  This objection was met by joining the two
triangles to form a rectangular shaped unit as depicted in Figure 13.
It is believed that this suggested basic design would maximize efficiency
and be economical for open basins.  Determination of optimum depth and
detention is contingent upon the provision of a basin with hydraulic
efficiency.

     The Texas Department of Health recommendations for the construction
and operation of hyacinth basins for upgrading stabilization pond
effluent is in the Appendix.  Adequate information is available for the
design of hyacinth culture basins which are to be employed in tropical
or sub-tropical regions.  Optimum design parameters will be required in
temperate climates using greenhoused hyacinth culture basins.

Discussion

     Objectives.  Residues (organic debris, animals, fish, plants, etc.)
resulting from advanced biological wastewater treatment (ABWT) are
viewed as being valuable products to be used for food, fuel, and fertil-
izer (National Academy of Sciences Report, 1979).  There is an increasing
universal interest in using wastewaters for the production of useful
products (Dinges, 1980).  Future development of ABWT is not restricted
to technical consideration alone, but will be determined by social
(philosophical) political and economic factors.
                               216

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           FIG, 13   SUGGESTED
              BASIC HYACINTH CULTURE
                  BASIN DESIGN
             DISTRIBUTOR
INFLUENT
              uuu
              14  H,
I-M DEPTH
                        EFFLUENT
                         "BARRIER
                              ALTERNATE
                                CULTURE
                                BASIN
                     •DISTRIBUTOR
             0,5% SLOPE
                                                    DRAIN
                                                    PIPE
                              217

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     Hyacinths may be used for livestock feed,  fuel generation,  and  to
improve micro-nutrient levels and moisture retention capability  of  soils
in arid areas.  Wastewaters have been considered as a liability  in  the
past.  Hyacinth culture is a means to reduce the negative economic
impact of wastewater renovation.

     A dichotomy exists, however, between the two desirable goals of
optimum, efficient wastewater treatment and maximum hyacinth production.
Efficient nutrient elimination is an objective of wastewater treatment.
Conservation and optimum utilization of fertilizer is a goal of  hyacinth
production.  Hyacinth production would require large land area and
entail costs for harvest machinery, labor, and energy.  These expenditures
would need to be balanced against the value of the product obtained.
The potential quantity of product would be limited by the volume of
wastewater available.  It follows that cities having large wastewater
flows would be the most likely candidates for mass hyacinth production.

     Nutrient Management.  Conserving and circulating nitrogen would be
a paramount consideration to maximize production.  Use of plant material
for methane generation would contribute to nitrogen conservation as it
is not lost during anaerobic fermentation.  Supernatant return to culture
units would restore nitrogen and permit the fixation of additional
carbon via plant growth.

     Hyacinths accumulate large amounts of potassium, but it is unlikely
that this macro-nutrient would be limiting in most instances.  Adequate
micro-nutrients would be available in incoming wastewaters.  Phosphorus
is present in wastewaters at levels which far exceed plant growth require-
ments.  One possible economical means of excess phosphorus removal might
be the addition of aluminium sulphate (alum) to the return digestor
supernatant.  Resulting sludge would be removed from the system.

     Much more efficient nitrogen removal may be obtained in properly
designed stabilization ponds than by hyacinth culture if the goal being
sought is effective wastewater  treatment.  Nitrogen reduction could best
be accomplished by utilizing a  combination stabilization pond—hyacinth
culture system.

     Temperature.  The hyacinth  is a tropical plant.  This does not
preclude their seasonal culture  in northern areas.  Corn is also a
tropical species.  Water temperature is a controlling factor in hyacinth
growth.  Water temperature near  the  freezing point will result in death
of the plants.  Francois  (1977)  determined hyacinth growth characteristics
at varying water  temperatures  in a phytotron.   It was found that active
growth was restricted  to  the range °f010  to 35  C.  Optimum growth was
obtained in  the range  from 25  to 27.5  C.  Two  days of exposure  to a
water  temperature of  45  C killed  the plants.

     Villamil, et al.  (1979) obtained sustained production of near
108.2  kg/ha'd, or 39.5 MT/yr  (dry weight) of hyacinth biomass in the
ideal  climate of  Puerto Rico.   It should  be pointed out  that these
productivity measurements were based upon the vegative multiplication
of plants.   It  is believed  that an even higher  rate of production
might  result if only  plant  stems and leaves were removed  (mown)  on a
periodic basis.
                               218

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     Continuous culture in open basins in Texas  is  feasible only  in the
sub-tropical climate of the Lower Rio Grande Valley.   Greenhouse  protec-
tion will be required elsewhere.  A single layer greenhouse cover will
probably suffice in most areas of Texas.   Insulated,  double layered
greenhouse covering may be needed in the  Panhandle  region.   Raw sewage
temperatures are usually above 10  C even in cold regions in the  abscence
of excessive infiltration into sewers. There is also the possibility of
installing solar collecting panels on properly oriented earthen berms
inside the greenhouse to enhance temperature conditions.  Deep culture
basins (3-m) supplied with diffused aeration as proposed by Stewart, et
al. (1979) might be advantageous.  A 0.4-ha aerated hyacinth treatment
system (open basin) receiving up to 1890  m -d of raw and partially
treated wastewaters is to be placed into  operation in the near future at
Port Arthur, Texas.

     Residue Management.  With one exception, continuous hyacinth
harvest is not being practiced in Texas.   A single, annual harvest is
being suggested to remove dried plants and basin debris from culture
basins.

     Sludge constitutes a greater proportion of basin debris than that
of plant biomass.  Continuous harvest in small hyacinth treatment systems
serves to disrupt treatment.  Open areas  in the mat allows algal growth
and desirable biota are removed with the plants.

     Application.  Hyacinth culture may be used in almost any instance
where there is a need to improve organic, or mineral water quality.
Hyacinth culture can be used as a complete treatment process with
unscreened raw sewage being introduced directly into the culture unit.
Effluent quality from such a properly designed system may be expected to
equal, or exceed that obtainable by conventional secondary processes.

     Seasonal hyacinth cultivation could be employed to remove excess
nutrients from small lakes.  Water from the subject lake would be pumped
to a hyacinth culture unit and  return by gravity flow.  The culture
basin would be taken out of operation, drained, and the accumulated
debris removed at  the end of each growing season.

     Upgrading secondary wastewater treatment plant effluent quality,
biomonitoring, pre-treatment of raw water supplies, removal of specific
chemical compounds, and the demineralization of brackish waters  are
other possible uses for hyacinth culture.

Concepts

     Biological Demineralization.  Many arid areas of  the  World  are
underlain by aquifers whose waters are saline.  Biological deminerali-
zation of brackish waters by hyacinth culture is an exciting possibility.
                                      219

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     About  20  percent  of  dry  hyacinth biomass  is ash  (minerals).  Plants
 grown  Ln  the Williamson Creek pilot  system  contained  a mean chloride
 coiitent of  6.35  percent on  a  dry weight basis.  Boyd  (1970) reported a
 chloride  level of  5.95 percent  (dry  weight)  in hyacinths.  Parra and
 llortenstine  (1974) determined the  chemical  composition of wild hyacinth
 populations  in Florida.   Maximum dry weight  percentages of elements
 found were:  Potassium -  6.5;  calcium - 2.41;  magnesium - 1.86; and
 sodium -  1.54.   Wolverton and McDonald  (1976)  recorded a 14 percent
 decrease  in  total  dissolved solids content  of  wastewaters treated in an
 open hyacinth basin at Orange Grove, Mississippi.

     Several million dollars  would be required to construct and fully
 evaluate  an experimental  prototype biological  demineralization facility.
 Should the concept prove  feasible, subsequent  systems would be quite
 economical as most energy requirements would be met through the genera-
 tion of methane  fron harvested hyacinths.  A possible design of such a
 facility  would involve the provision of lined  basins  covered with greenhouses
 having triple layers of clear plastic.  Nutrient input could be livestock
 wastes.   Appropriate recirculation of effluent to dilute incoming flow
 to a salinity level permitting hyacinth growth would be necessary.
 Refrigerated air would pass through  the inner  layer of the cover to
 enhance condensation of water vapor  produced from evapotranspiration and
 to reduce interior air temperature.  Collected condensate would be
 returned  to the  influent.   Continuous hyacinth harvest would be practiced
 and ammonia extracted  from digestor  supernatant would return to the
 culLure basins .

     Crop Production.  Hyacinths normally float upon a water surface.
 They will grow equally well in moist, enriched soil as shown in Figure
 .14.  The  possibility exists to grow  hyacinths as a field crop utilizing
 flood irrigation.  Conceptual design of a field crop production system
 is presented in Figure 15.  Production paddies would be drained and
 allowed to dry somewhat prior to harvest.   Plants could be mown period-
 ically with light weight machines equipped with ballon tires.   (This
would depend upon a favorable response of plants to cropping.)

     Transport.  Vehicular transport of fresh hyacinths is energy inten-
 sive as 95 percent of the  cargo consists of water.   Transport of hyacinths
 for short distances to methane generation digesters, or to livestock
 feed processing  facilities may possibly be accomplished via pipeline.
 Sufficient water  would be  added to fine chopped plant material  to form a
 slurry which could be pumped through piping.

     Aquatic Harvest.  One approach  to continual harvest of plant material
 for nutrient removal without interfering with treatment efficiency
might be such a scheme as  depicted in Figure 16.   Land based harvest
 equipment could be employed for mowing the plants.   Leaves and  stems
would represent a more desirable product for livestock feed than the
 entire p1 ants .
                                    220

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Fig. 14  Rooted Plants Growing in Moist
      Soil Adjacent to a Hyacinth
         Culture Basin, 1979.
      (Courtesy of H.  Nordmeyer)
                      221

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                     FIG,  15  CONCEPT - HYACINTH  CROP PRODUCTION  IN

                                    IRRIGATED SHALLOW PADDIES
       INFLUENT
to
fO
NJ
MOWN PERIODICALLY
                          ROOTED IN SOIL
                                                 AGRICULTURAL
                                                  DRAIN PIPE
RECIRCULATION
        Ci
                                   IMPERVIOUS
                                     LINER
                                                       RRIGATION
                                                      AILWATER


                                                       UMP

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FIG, 16  CONCEPT - HYDRAULIC  ELEVATION OF
              CHANNEL GROWN HYACINTH
               TO FACILITATE  MACHINE
                 HARVEST BY MOWING
                         PRE-
                          0,3-M  DEPTH
                              Ey MODE
                          1,2-M DEPTH
                                         ROAD BED
.rRE:MY!-!L,,.. „ .*.,
M£V» vM'"*/«IV*V*''»1* 'A\ J.V?» V." '."I
                                         ROAD BED
                           0,3-M DEPTH
                                          ROAD  BED
                        223

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 CONCLUSIONS
      1.   Sufficient information  is available for designing hyacinth
          treatment facilities  to be employed in warm climates.

      2.   Optimal design of culture basins is necessary to minimize
          areal requirements and  greenhouse costs in temperate climates.

      3.   Hydraulic loading is  the most critical consideration in
          culture basin design.

      4.   The primary pollutant removal mechanism of hyacinth treatment
          is the reduction of suspended particulate content.

      5.   Harvest of hyacinths disrupts treatment.  Provision of
          multiple culture basins to allow alternate operation is
          desirable.  Each culture basin should be drained and the
          accumulated sludge and plant debris removed on an annual
          basis.

      6.   Hyacinth culture may be employed as a complete treatment
          process.

      7.   Nitrogen management is a key factor in utilizing hyacinths
          for wastewater treatment, or for biomass production.  Stabilization
          ponds can be designed for effective nitrogen reduction.
          Hyacinth culture will remove most remaining nitrogen in pond
          effluent, especially that which is in the organic form (algae).

      8.   Stabilization ponds followed by hyacinth culture constitutes
          a highly effective wastewater treatment system.

      9.  A hyacinth treatment system is capable of producing effluent
         having a mean content of <10 mg/1 BOD- and TSS.
                           ACKNOWLEDGEMENTS
     Our gratitude is extended to the City of Austin for facilities
provided for the pilot studies and the full-scale study underway at the
Williamson Creek wastewater treatment plant.  Special thanks are given
to Mr. Herbert Nordmeyer, Enforcement Division, Texas Department of
Water Resources, for assembling data on hyacinth wastewater treatment
systems in the Rio Grande Valley and for photos provided.  We also wish
to acknowledge the cooperation of officials of the Rio Grande Valley
Pollution Control Authority, the City of Rio Hondo, and the City of San
Benito.
                                     224

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 1. Boyd, C.,  1970.  Vascular Aquatic Plants for Mineral Nutrient Removal
   from Polluted Waters.  Economic Botany  24:95-103.

 2.  Dinges,  R. 1979.   Stabilization Ponds.   Chapter in Manual of
    Wastewater Operations,  5th edition,  Texas  Water Utilities
    Association,  Lancaster Press,  Lancaster Pennsylvania (In Press).

 3.  Dinges,  R. and Rust,  A.  1970.   The  Ennis Study Experimental
    Chlorination of Stabilization Pond  Effluent.  Report - Texas
    Department of Health, Austin,  Texas,  pp.  117.

 4.  Dinges,  R. 1973.   Biological Demineralization of Water.
    Report -(Unpublished) Texas Department of  Health,  Austin,
    Texas.   pp. 21.

 5.  Dinges,  R. 1976.   A Proposed Integrated Biological Wastewater
    Treatment System.   Chapter in Biological Control of Pollution.
    Univ.   of Pa. Press,  Philadelphia,  Pa. pp. 225-235.

 5  Dinges R. 1976.  Water Hyacinth Culture for Wastewater Treatment.
    Report - Texas Department of Health, Austin,  Texas,  pp. 143.

 7.  Dinges,  R. 1980.   Natural Systems for Water Pollution Control.
    Van Nostrand Reinhold, New York, N.  Y. (In Manuscript).

 8.  Francois, J. 1977.  Quelques Reactions Thermiques De La
    Croissance Chez Eichhornia Crassipes (Mart.)  Solms-Et Leur
    Formulation Analytique. Report - Univ. Catholique de Louvain,
    Belgium,  pp. 33.

 9.  Nuese, D.  1976.   The Removal of Algae From an Oxidation Pond
    Effluent Through the Use of a Tertiary Water Hyacinth Pond  System.
    MS Thesis, Texas Univ., Austin.  pp. 62.

10.  Parra, J. and Hortenstine, C. 1974.   Plant Nutritional Content
    of  Some Florida Water Hyacinths and Response by Pearl Millet
    to Incorporation of Water Hyacinth in Three Soil Types.  Hyacinth
    Control Jour.  8:42-44.

11.  Smallhorst, D.F.   1963.  The History of Oxidation Ponds  in  the
    Southwest.  Environ. Health (India). 5:70-75.

12.  Stewart, W., Alsten, C., Serfling,   S. and Mendola, D. 1979.
    Pilot Studies of the Solar Aquacell Controlled Aquaculture
    Process for Wastewater Reclamation,  Paper presented at the
    A.W.W.A. Conference on Wastewater Reuse.  Washington. D.C.
                                      225

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13.  Villamil, J.,  Clements,  R.,  Block,  McB.,  Weil,  P.,  Garcia,  G.,
     Lao, W., Rosa, L.  and  Santos,  F.  1979.  Water Hyacinths  for
     the  Clarification  of Wastewaters  and  the  Production of Energy.
     Report  - Center  For Energy  and Environment  Research,  Univ.  of
     Puerto  Rico.,  San  Juan,  P.R.   pp.  30.

14.  Wolverton,  B.  and  McDonald,  R.  1976.  Water Hyacinths for
     Upgrading Sewage Lagoons to  Meet  Advanced Wastewater Treatment
     Standards:  Part II.   NASA  Tech.  Memo.  TMOX-72730.   Bay  St.
     Louis,  Miss.   pp.  13.

15.  Wooten, J.  and Dodd, J.   1976.  Growth  of Water Hyacinth
     in Treated  Sewage  Effluent.  Economic Botany,  30:29-37.
                              226

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*APPENDIX*
           227

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                     TEXAS DEPARTMENT OF HEALTH

              RECOMMENDATIONS FOR THE CONSTRUCTION AND
                  OPERATION OF HYACINTH BASINS FOR
                UPGRADING STABILIZATION POND EFFLUENT
                             May 4, 1979

        These recommendations are subject to modification as
       more information on operating systems becomes available
                               DESIGN
1.  Basin Sizing - Hyacinth basins should be sized for a maximum
    surface loading rate of 0.2 mgd/acre with a mean water depth
    of three feet.  A maximum basin size of one acre is recommended.

2.  Basin Configuration - Rectangular basins having a length to
    width ratio of at least 3:1 would be preferable.  Basins should
    be designed to approach plug-flow conditions.  Influent should
    be introduced at intervals along the upper margin of the basin.
    This may be accomplished via a perforated pipe having a minimum
    diameter of 10 inches.  Perforations should be spaced at a maximum
    distance of 10 feet apart and be at least two inches in diameter.
    Increased efficiency may be attained by dividing a rectangular
    basin into equal parts by a diagonal, low earthen dike.  Influent
    would be distributed along the base of one right triangle,
    collected at the apex, and reintroduced along the base of the
    other triangle.

3.  Basin Construction - Basins should be constructed by excavating
    and diking the required area.  Exterior dikes should have a
    top width of ten feet and sides with a vertical to horizontal
    slope of 1:3.  Minimum freeboard should be two feet.  An access
    ramp must be provided with a width of at least 10 feet.  Basins
    should be designed for rapid drainage.  The bottom of a culture
    unit would be smooth and slope at least 0.5 percent from the upper
    to lower end of the basin.  A sump should be excavated at the
    lower end of a culture unit to facilitate removal of residual
    waters by draining or pumping back to the stabilization  pond.

4.  Dual Systems - Duplicate systems, each having a capacity to treat
    the permitted average daily flow of the facility, must be provided.
    Constant inflow, controlled by a valved pipe, should be maintained
    to a culture basin.  The feeder stabilization pond should serve
    for flow equalization with the water level being allowed to
    fluctuate.  An appropriate transfer structure should be provided
    to permit only surface stabilization pond waters to enter a
    hyacinth culture basin.
                                      229

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5.  Basin Piping - Piping should be installed in such a manner as to
    allow parallel, or series operation of the culture basins. Basins
    should be interconnected at the lower ends by a valved pipe having
    a minimum diameter of 10 inches.  A valved drain pipe must be
    provided in each basin and laid on a level with the bottom of the
    excavated sump near the basin outlet.

6.  Barrier - A fixed barrier creating a clear zone of approximately
    1.0% of the basin surface area must be installed around the outlet
    to retain the hyacinth plants, allow for reaeration, and prevent
    the discharge of plant debris.  While screen may be used as a
    barrier material, a permeable crushed rock or gravel dike is
    preferred.  If screens are used at least two must be provided with
    the outer screen having a mesh size of not more than one inch and
    the inner screen having a mesh size of not more than 1/4 inch.  An
    outlet box with an adjustable flow measuring weir must be provided
    and located in the clear zone.

7.  Mosquito Control - Galvanized wire mesh exclosures eight to ten
    feet in diameter and at least four feet in height should be placed
    at intervals throughout a basin to furnish clear areas to enhance
    fish production for mosquito control.

8.  Fencing - The hyacinth basins must be enclosed by a man-proof
    fence with a locked gate.

9.  Depth Control - A gauge should be provided to indicate water
    depth in a hyacinth basin.
                              OPERATION
1.   Continuous Operation - In areas where hyacinths may be grown
    year-round, the basins may be operated on a continuous basis with
    each basin receiving one-half the average daily wastewater flow.
    Once each year the basins should be cleaned by diverting all the
    wastewater through one basin while dewatering and removing hyacinth
    plants and sludge from the other basin.  The cleaned basin should
    then be refilled via the interconnected piping with effluent from
    the full basin and restocked with hyacinth plants.

2.   Seasonal Operation - In colder regions only seasonal operation
    will be permitted since the hyacinth plants freeze at a temperature
    less than 32 F with a resulting decrease in treatment efficiency.
    At the time when plants are frozen or a decrease in effluent water
    quality is noted the culture basin should be drained immediately,
    allowed to dry and cleaned.  Wastewater must be stored or treated
    in some other approved manner during this period if it is not of
    sufficient quality to meet Texas Department of Water Resources
    permit requirements.  The standby alternate basin may be filled and
    planted when the danger of frost is over.
                                    230

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3.  Cleaning - Draining of a hyacinth basin is initiated by closing
    the influent valve and opening the drain valve.   Rainwaters collecting
    in the drain sump during the drying period should be removed quickly
    by pumping into the stabilization pond.  The basin should be cleaned
    thoroughly using appropriate equipment. Dried plants and sludge
    removed from a basin may be landfilled, converted into compost for
    use in parks or nurseries, or used for soil amendment of agricultural
    land used for grazing, or the production of grain and fiber crops.
    Care should be excercised in handling materials^ removed from culture
    basins to assure that it does not gain access to publicT waters^

4.  Records - Sampling - Careful records should be maintained on the
    water depth, flow rate and other operating parameters of the
    system.  It would be desirable to sample the raw wastewaters and
    influent-effluent of the hyacinth basin on a weekly basis.

5.  Mosquito Control - Hyacinth basins should be stocked with Gambusia
    (mosquite fish-pot bellied minnows-top water minnows) to assure
    that mosquito production is supressed.  Other species which may be
    stocked to supplement mosquito fish are Poecilia (green sailfin
    mollies) and Astyanax (Texas tetra-Rio Grande jumping minnow-mud
    minnow).
                                      231

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A WATER HYACINTH ADVANCED WASTEWATER TREATMENT SYSTEM

Dan Swett, Development Research Manager, Coral
  Ridge Properties, Coral Springs, Florida
     A one year field experiment at the 378,530 Ipd (100,000 gpd)
level has demonstrated that a system of 5,035 m2 (54,200 ft2) of
water hyacinth (Eichornia crassipes) lagoons can provide advanced
treatment to effluent from an activated sludge plant by achieving
removal rates of 67% for total suspended solids, 98% for biochemical
oxygen demand, 97% for total nitrogen and 79% for total phosphorus.
Biomass produced by the system offers a potential for energy,
fertilizer or fodder production.
PROJECT DEVELOPMENT

      Coral Springs, Florida, is a "New Town" developed by Coral
Ridge Properties, a wholly owned subsidiary of Westinghouse Electric
Corporation, located in the northwestern portion of Broward County.
With  a current population of 30,000, Coral Springs is adding
population and dwelling units at a rate of 7.5% per year making  it
the fastest growing municipality in  the Fort Lauderdale urban  complex.
      Almost all  of the current growth and development is occurring
in the southern  portion of the city  where water, sewer and waste-
water treatment  services are provided by the Coral Springs Improve-
ment  District, a special taxing body created by act of the state
legislature.  The District's wastewater treatment plant has a  design
capacity  of  7.6  mid, that will ultimately be expanded to  20.6  mid.
Method of treatment is by activated  sludge, with effluent disposal
into  a closed seepage lagoon.
      Although the treatment plant produces a secondary effluent  that
meets current state and county standards, the  Broward County
Commission has adopted an ordinance  requiring  that, as of January  1,
1980, all non-ocean effluent discharges meet the advanced wastewater
treatment standards of 5 mg/1 total  suspended  solids, 5 mg/1 BOD^,
3 mg/1  total nitrogen and 1 mg/1  total phosporus.
      This situation is further complicated by  the  fact  that  Broward
County  is committed to the  regional  treatment  system  concept and has
received an  EPA  grant for installation of such a system.   The  Coral
Springs  Improvement District has  been asked  by the  county  to join
                                      233

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the regional system as soon as sufficient capacity becomes available,
which is expected to occur sometime between 1983 and 1985.  Some
portions of this system are in place, others under construction, and
others still in the planning stage.
     The District is thus faced with the necessity of upgrading its
existing secondary treatment system to meet AWT standards by 1980.
Under normal circumstances, installation of conventional AWT facili-
ties with twenty year amortization would impose a large financial
burden on the District.  This burden would be rendered totally in-
tolerable should the new facilities have to be abandoned within three
to five years upon integration of the District into the Broward
County regional wastewater treatment system.  Project Hyacinth
represents an effort by Coral Ridge Properties to find a low-cost
way out of this dilemma for the Coral Springs Improvement District.
     Funded entirely by Coral Ridge Properties, Project Hyacinth
was designed by Gee and Jenson, the District's consulting engineers,
to bring 378,530 Ipd (100,000 gpd) of the treatment plant effluent
to AWT standards.  Constructed on 0.93 hectares (2.31 acres) of
District-owned land, the system consists of a series of five ponds
with a total water surface area of 0.5 hectares (1.25 acres) (Fig. 1).
Design treatment time at the 378,530 Ipd capacity is two days in
Pond A and one day in each of Ponds B through C, for a total of six
days.  Water depth throughout the system is 38.1 cm (1.25 feet).  An
impermeable asphalt seal on sides and bottoms of the ponds prevents
seepage loss (Table 1).  Total construction cost of the system was
less than $65,000.  On completion of construction, ponds were filled
with effluent and "seeded" with approximately 7.64 m^ (10 yds.3) of
water hyacinth plants (Eichornia crassipes) per pond.  This was
accomplished on January 27, 1978.
     Increase in the plant biomass was slower than anticipated, due
primarily to excessive chlorination of the effluent at the treatment
plant.  When this condition was corrected and chlorine residual of
influent into the system reduced to approximately 1 mg/1, plant bio-
mass increased rapidly.  Some harvesting was accomplished during the
biomass increase period to remove dead and malnourished plants.
SPLIT FLOW OPERATION

     Data collection began May 15, 1978, with 90% coverage in all ponds.
The project sampling plan called for simultaneous 24-hour composite
sampling at the Pond A influent point and the Pond E effluent point
to establish levels of analytical variables achieved by treatment in
the full system at the design time of six days, and thereafter move-
ment of sampling forward to outflow points of Ponds D, C and B to
establish levels achieved by curtailing treatment time to five, four
and three days.  This plan was adhered to through November, 1978,
except that effective June 13, composite sampling time was increased
to 48 hours, halving the number of samples to be analyzed each month.
     Metering of influent and effluent flows established a high evapo-
transpiration loss, amounting to 16.24 x 10  Ipd (42,900 gpd) or
32.35 Ipd/m  (0.7915 gpd/ft2) of water surface.  This loss appears
                              234

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  constant  due  to  the  high  liquid  uptake  of  the  plants  and  therefore
  is  unaffected by flow  into  the system
       In December,  1978, because  surge'overloads at  the  treatment
  Plant were  causing high solids inflows  into  the system, the  sampling
  plan  was  amended to  include grab sampling  every other day at the
  outflow point of each  pond  to trace progress of solids  and nutrients
  through the system  This grab sampling revealed a  consistent drop
  in  levels of  analytical variables between  the  influent  point and  the
  Pond  A outflow point,  then  an increase in  these variables at Se
  Pond  B outflow point,  followed by decreases at the  outflow points
  of  Ponds C, D and  E.   To insure  that  the increase in  analytical
  variable levels  from Pond A to Pond B was  not related to  the ?ime
  of  grab sampling,  four additional composite samplers were placed in

  frr±np°nd f "Jr  1§ 19?9' ^ 48 h°Ur '""POBlte  samples drawn
  from  the Pond A  influent point and the effluent point in  each pond.
       This composite sampling verified that concentrations  of an-
  alytical variables increased in Pond B and decreased  thereaftS
 Removal of hyacinth plants from the inflow end of Pond B  revealed
  that  influent was entering the pond from two points - from  Pond A
 and also directly from the treatment plant influent line.   On
 investigation, valves installed to permit shunting of influent flow
 into either Pond A or Pond B were both found to be open,  resulting
 in simultaneous fTo. -in^  X«M, _,_   closure      P ValJeS^tlng
 February 28979
 into  Pond A and  55% into  Pond B.   An equation was  foliated to  *
 enable calculation  of  total  flow  into Pond  B,  consisting of outflow
 from  Pond A (inflow into  Pond A less evapo-transoiration ?„„   i
 flow  into Pond B directly from the treatment  "ant)?  A second"
 equation  was formulated to calculate the  combined  concentration of
 analytical variables entering Pond B as a result of  the combined
 inflow from Pond A  and from  the treatment plant  (appendix)
      Adjusted influent loadings into Pond B during the split flow
 period for liters per day, total  nitrogen and  total  phosphoruf  are
 shown in  Table 2.   Because effect of the
 solid, «* BOD5  _ ne8libible, no
 D13.Q.6 •
             °f '^ hyacinth treatment, based on the system of Ponds
          K  ^e ShOWn ^ TablG 3'  Treatment times shown^n  this
table are based on total loadings into Pond B and are adjusted for

CVand°"DrdanrSPlraT10n      " ""* P°°d'  ^ ^ samples' from Ponds
to 10:^0 a m?8 ^^ ™* ^^ &t the ^ "« time of 9:30
UNITARY FLOW OPERATION

     Flow into Pond A only was restored on February 28, 1979, and
                                      235

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data collection during the period March 1 - May 31, 1979, was
accomplished by 48 hour composite sampling at the Pond A influent
point and at the outflow point of each pond.  Influent flow was
maintained at 435,102 Ipd (115,000 gpd) throughout, except for 48
hours in April and 12 hours in May when flows were reduced to zero.
Knowledge gained from the previous nine months of experimental
operation was used to operate the system for maximum efficiency.
     During the period, nitrogen removal rates ranged from 62% to
96%, and phosphorus removal rates ranged from 18% to 60%.  Reduc-
tions in mass loadings for these two variables, adjusted for evapo-
transpiration loss, and removal rates achieved according to treat-
ment time are contained in Tables 4 and 5.
     Treatment plant operations during the months of April and May
were erratic due to construction activities and were reflected in
abnormal variability of pollutant concentrations in influent into
the hyacinth system.  On April 17, construction was completed on
3,785,300 Ipd (1 mgd) of new treatment plant capacity and inflow
into the hyacinth system was completely shut off for 48 hours to
enable rapid filling of the new tanks.  Problems with the new plant
operation necessitated its shutdown on April 19 for debugging, with
restoration of flow into the hyacinth system, as which time transfer
back to the old plant resulted in a heavy inflow of untreated solids
into the hyacinth system.
     On April 25, unusual weather conditions dumped 36.8 cm (14.5
inches) of rain on the area in less than 24 hours.  This rainstorm,
calculated as having a probability of occurrence of less than once
in 200 years, created temporary flood conditions that again caused
plant operational problems and heavy inflows of untreated solids
into the hyacinth system for 48 hours.  Despite these two treatment
upsets, the only effect on the hyacinth system was the onset of
chlorosis in plants in Pond E, caused by undernourishment resulting
from the two day shutdown of flow into the system.
     During May, efforts to restore normal treatment in the plant
caused pollutant concentrations in the influent into the hyacinth
system to rise steadily from the first of the month, culminating in
highs of 22 mg/1 total suspended solids, 110 mg/1 BOD5, 132.29 mg/1
total nitrogen and 44.52 mg/1 total phosphorus on the 21st.  In
addition, influent flow into the system was shut down from 10:00 p.m.
on the 22nd to 10:00 a.m. on the 23rd.
     It is noteworthy that during the period of the heaviest pollutant
concentration inflow, the hyacinth system demonstrated the highest
degree of efficiency in nutrient removal, apparently as a result of
increase in the N:P ratio.  When the N:P ratio was at its highest,
2.97:1, on May 21, total nitrogen and total phosphorus concentrations
at the Pond C outflow point were 0.86 and 0.87 mg/1, respectively,
on May 26th and 0.74 and 0.71 mg/1 on May 28th.  This indicates
that the most effective nutrient removal occurs when the influent
N:P ratio is approximately 3:1.
     Influent loadings into the system and analytical variable con-
centrations at the outflow point of each pond for the March 1 -
May 31 period are contained in Table 6.  Extremely high variability
in loading concentrations of each variable during May are shown by
the standard deviations.  These concentrations were reduced to almost
                              236

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negligible amounts as they flowed through the system.  Because
the overall effect of any effluent discharge is more a function
of the total amount of each pollutant contained in the effluent
than the concentration thereof, it is worthwhile to consider total
contents of each variable on a mass loading basis at the hyacinth
system influent point and at the outflow point of each pond.  Table
7 presents these data for the period March 1 - May 31, 1979, based
on daily flow into the system and adjusted for evapo-transpiration
loss in each pond.
CONCLUSIONS

     Because achievement of nitrogen removal is the most difficult
and expensive aspect of conventional advanced wastewater treatment
processes, treatment time required by a hyacinth system to achieve
any desired concentration of total nitrogen in final effluent is a
crucial planning factor.  The scattergram (Figure 2) portrays the
actual relationships between treatment times and total nitrogen
concentrations achieved by Project Hyacinth (grab sampling data not
included).  Analysis of the total nitrogen-treatment time relation-
ship by linear regression enables use of the least squares equation
to predict the treatment time required to achieve any desired con-
centration of total nitrogen.

     Data contained in Table 6 yields the least squares prediction
equation:

              Y = 3.91 + (-0.65)X,

in which Y = mg/1 total nitrogen and X = days' treatment time.
Correlation coefficient for the equation is -0.60.  By this  predic-
tion equation, for a Y value of 3.00 mg/1 nitrogen, 1.4 days treat-
ment is required over a system with 1 m^ of water surface per 86 Ipd
effluent.  Standard deviation of the predicted Y at this level of
X is 1.34, thus to achieve the indicated confidence levels,  treat-
ment times as follows would be required:

         Confidence Level             Days' Treatment
              99%                          4.95
              97.5%                        4.3
              95%                          3.77
              90%                          3.21

     Experience gained  during the  year of Project Hyacinth  operation
indicates that, while the system can  successfully cope with a
variety of stresses, health of the plants must be maintained for
most effective treatment.  While the water hyacinth is a hardy,
disease-resistant plant that thrives  at all above freezing  tempera-
tures,  its growth rate  and nutrient uptake efficiency  can be com-
promised.
     Presence of a high chlorine residual definitely  inhibits  plant
growth.   If  possible, effluent chlorination should be  accomplished
                                      237

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subsequent to hyacinth treatment.  If local conditions dictate pre-
hyacinth chlorination, care should be taken that chlorine residual
in  the influent does not exceed 1 mg/1.  Plant health is also
adversely affected by chlorides.  Early in the project's operation
189 liters (50 gallons) of a 40,000 mg/1 NaCl solution were injected
at  the influent point in an effort to trace progress of the solution
through the system by continuous conductivity readings.  Three days
of  readings along the length of Pond A showed no chloride presence,
indicating total uptake of the solution by the plants.  Three days
later, plants in a fifteen foot wide strip down the middle of Pond A
exhibited severe chlorosis (leaf yellowing).
     Maintenance of nourishment is essential to plant health.
Hyacinth has a voracious appetite, which if not satisfied also results
in  chlorosis and decreased uptake efficiency.  Least efficient per-
formance of the system was obtained during periods of significantly
reduced influent flow and during periods when influent nitrogen con-
centration dropped below 10 mg/1.  Plant health is also adversely
affected by overcrowding.  During July and August, 1978, no plants
were harvested for a period of more than six weeks to determine
effect of overcrowding.  Chlorosis began to appear after four weeks
and increased in severity rapidly, accompanied by a decrease in up-
take efficiency.
     The best indication of plant health is an abundant growth of
dark green leaves.  Any appearance of stunted leaf growth with
yellowish green leaves in immature plants or of leaf yellowing in
mature plants should be investigated immediately.
     Intense sun with temperatures in the mid-nineties may cause some
leaf browning and wilting.  This is not a serious condition if new
growth is present, beneath the brown wilted leaves.  Wilted-leaved
plants may be removed during the normal harvest cycle by selective
harvesting.
     Healthiest plant condition and best system performance was ob-
tained when ponds were maintained in a loosely packed condition by
a four week harvest cycle.  From 15 to 20% of the plants should be
removed at each harvest.   Uncovering more than 20% of pond surface
area will result in an algae problem.  Harvest biomass on the four
week cycle averaged 137.6 mr (180 yds-*) , or 1 m^/36.6 m^ of pond
surface.
     During the year of Project Hyacinth operation, the biomass
growth rate appeared totally unaffected by seasonal temperature
variations.   Fahrenheit temperatures ranged from the mid-thirties
to low seventies during January and February, from the forties to
low eighties in the spring and fall, and from the upper seventies
to upper nineties during the summer months.
     When Project Hyacinth was designed, it had been planned to
harvest with a weed bucket-equipped front-end loader.  This proved
impractical because the 38.1 cm water depth affected the front-end
loader's hydraulic system.  A Gradall was used for two harvests but
was discontinued because hydraulic fluid from the boom dripped into
the ponds, and also because of its high cost.  The best performing
harvesting equipment was a weed-bucket equipped, truck-mounted drag-
line.  This equipment, with a dump truck, was able to accomplish a
                              238

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normal harvest in six to seven hours.  Had the ponds been fifteen
feet narrower, dragline harvesting efficiency would have been im-
proved considerably.
     Throughout Project Hyacinth, persistent clogging of the
influent flow meter made accurate determination of influent flow
rates difficult.  Occasional shut-off, both intended and non-intend-
ed, of influent flow also caused serious problems.  In a full-
scale system, reliable influent and effluent flow metering and an
influent flow system not subject to shut-off or clogging would be
essential.
     In Project Hyacinth, harvested plants were placed on a con-
crete drying pad between Ponds A and E, draining into Pond A.  Two
to three weeks' drying resulted in a 75% volumetric reduction in
the biomass.  The dried biomass was removed to a tree nursery and
composted.  It proved to be a superior fertilizer.
     Project Hyacinth has proven that a 0.4 hectare/378,530 Ipd
(one acre/100,000 gpd) water hyacinth treatment system is capable
of bringing secondary wastewater effluent to AWT standards for total
suspended solids, BOD^ and total nitrogen in three to five days,
depending on confidence level required.  Further investigation is
underway to determine if the influent N:P ratio can be increased
sufficiently by ammonia addition to achieve sufficient phosphorus
uptake to meet the AWT standard for this element.  If so, it must
also be determined if such ammonia addition is cost-effective
compared to chemical precipitation for phosphorus removal.
     At any rate, there appears to be no doubt that even with
addition of chemical phosphorus removal, a water hyacinth AWT system
can be much more cost-effective in both capital and operations and
maintenance costs than a conventional AWT system.
     Given the present state of the art, for small sun-belt
communities, in which freezing temperatures are of very short
duration and land is available, water hyacinth treatment now pro-
vides an excellent low cost means of bringing small activated sludge
plant effluent flows  (400,000 Ipd or less) to AWT standards.  For
larger communities with effluent flows in excess of 400,000 Ipd,
disposition of the harvested hyacinth biomass may require a by-
production process.  Depending on local geographic and economic
considerations, the harvested biomass may be used for energy,
fertilizer or fodder production.  Additional field research is
required in these areas.
                                     239

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 Appendix

 1.  Adjustment  equation for  influent  flow split between Ponds  A
 and B:

    QB • Q -  EA

    where Q   =  total flow into system, Ipd,
          Qg  =  flow into Pond B, Ipd, and
          EA  =  evapo-transpiration loss in Pond A, Ipd.

 2.  Adjustment  equation for concentration of any variable entering
 Pond B as result of split influent flow:

    CM = 0.55QCi + (0.45Q-EA) CAe
    where Q, Qg and Ei are as in Equation 1, and
          Ci  = concentration in influent into system, mg/1,
          GBi = concentration entering Pond B, mg/1, and
          GAe = concentration leaving Pond A, mg/1.

3.  Adjustment equations for treatment time:
a.  Pond A, Split influent Flow:

    TA =        2 VA	
         Q(0.45) + (Q(0.45)-EA)

    where Q and EA are as in Equation 1,
          TA = Time in Pond A, days, and
          VA = Volume of Pond A, liters.

b.   Pond A, Unitary Flow:

    TA =   2 VA	
         Q + (Q-EA)
    Ponds B through E:
                    2 VT
                        . • • • • E
    Tfi ..... E = QiB ..... E +
    where TB ..... E = Time in designated pond, days,
          ^B ..... E = Volume of designated pond, liters,
          QiB....E = Inflow into designated pond from preceding
                     pond, Ipd,
              ...E = Outflow from designated pond; i.e., inflow from
                     preceding pond minus evapo-transpiration loss
                     in designated pond.
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d.  Adjusted system treatment time:

    Ts ' TA + TB +	TE

    where Ts = Time in system, days.

4.  Table of volumes and evapo-transpiration losses:

           Volume      Evapo-Transpiration      Cumulative Loss
Pond      (liters)         Loss (Ipd)               (Ipd)
 A        645,772            58,369                 58,369
 B        282,761            26,005                 84,374
 C        282,761            26,005                110,379
 D        282,761            26,005                136,384
 E        282,761            26,005                162,389
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Table 1
Project Hyacinth Design Data

                 Pond A          Ponds B-E ea.      Total System
Dimensions
   (Inside)  26.82 m x 83.82 m  26.82 m x 39.62 m  61.87 m x 131.67 m
Water
  Surface
  Area          1,810 m2             806 m2           5,035 m2
Water
  Capacity    645,772 1          282,762 1        1,776,820 1
Treatment
  Time at
  378,530
  Ipd            2 days             1 day              6 days

Influent to Pond A;  through 7.62 cm (3 inch) i.d. pipe

Pond connecting pipes:  30.5 cm (12 inch) i.d.

Berms:  4.57 m (15 feet) between ponds, 1.83 m (6 feet) outside
of ponds.

Effluent from Pond E:  Outflow over 90° V-notch wier, 15.2 cm
(6 inch) deep.  Maximum capacity, 730.6 1pm (193 gpm).
Meters:

  Influent - Badger model MLFT-SGH 7.6 cm  (3 inch) propeller meter.

  Effluent - Leupoldt Stevens model 61R flow recorder.
                              242

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 Table 2
 Pond B
 Adjusted Influent Loadings
Dates

5/15-6/5/78
6/13-7/31/78
8/1-31/78
9/1-30/78
g 10/1-31/78
11/1-30/78
12/1-31/78
1/1-31/79
2/1-28/79
LPD

3.2 x 105
2.33 x 105
2.32 x 105
3.45 x 105
3.0 x 105
3.28 x 105
3.54 x 105
3.77 x 105
3.77 x 105
TSS*
Mean Std. Dev.
mg/1
6.40
5.80
2.80
2.87
2.43
—
16.33
7.20
3.93
mg/1
4.18
5.60
0.99
0.62
0.49
—
21.07
3.71
1.10
Mean
mg/1
5.81
8.33
3.25
2.67
3.00
—
7.75
4.25
4.25
BOD5*
Std. Dev.
mg/1
1.29
8.81
0.43
0.47
0.70
—
2.69
0.43
0.43
Total N
Mean Std. Dev.
mg/1
7.78
7.47
8.08
6.58
7.68
8.96
9.84
9.39
7.81
mg/1
1.90
1.45
2.46
1.33
1.03
1.24
1.47
1.82
1.17
Total P
Mean Std. Dev.
mg/1
5.55
5.18
5.51
5.93
6.29
4.74
6.72
5.88
4.99
mg/1
1.57
1.36
1.18
1.47
1.10
1.28
1.29
0.49
1.48
* Unadjusted Loading

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Table 3
Pond C Effluent


Adj. Treatment
Dates Time (Days)
9/1-30-78
10/1-31/78
11/1-30/78
12/1-31/78
1/1-31/79*
NJ
*• 2/1-28/79
Pond D Effluent
8/1-31/78
10/1-31/78
11/1-30/78
12/1-31/78
1/1-31/79*
2/1-28/79
2.27
2.33
2.10
2.10
1.93
1.93

6.43
4.21
3.71
3.33
3.04
3.04
TSS
Mean
mg/1
3.80
3.75
—
—
4.33
3.71

4.07
—
3.60
5.16
4.13
3.21

Std. Dev.
mg/1
0.65
0.43
—
—
0.87
0.79

1.29
—
1.36
0.90
1.36
0.56
                                                    BOD5              Total N            Total P
                                                Mean   Std.  Dev.    Mean   Std.  Dev.    Mean   Std.  De
                                                mg/1     mg/1      mg/1     mg/1      mg/1     mg/1

                                                                   3.22     1.15      5.31     0.53

                                                                   3.90     0.91      6.00     0.34

                                                                   5.10     2.34      4.39     0.85

                                                                   6.13     1.47      4.12     0.63

                                                                   4.71     1.21      5.53     0.36

                                                                   3.43     1.19      4.75     0.11
                                                3.67     0.94      1.00     0.37      4.95     0.96

                                                                   1.85     0.54

                                                                   2.53     1.09      4.03     0.74

                                                                   4.00     1.15      4.33     0.43

                                                                   3.39     1.52      5.19     0.50

                                                                   2.20     0.90      4.61     0.39

-------
      Pond E Effluent
Ol
                                       TSS                BOD5               Total  N            Total P
                  Adj. Treatment   Mean   Std. Dev.   Mean   Std. Dev.   Mean    Std.  Dev.    Mean   Std.  Dev.
Dates
5/15-6/5/78
6/13-7/31/78
10/1-31/78
11/1-30/78
12/1-31/78
1/1-31/79
2/1-28/79
Time (Days)
5.51
9.83
6.09
5.30
4.70
4.30
4.30
mg/1
3.77
3.28
3.17
3.71
2.67
3.20
3.07
mg/1
1.42
1.30
0.69
0.88
0.94
0.70
0.59
mg/1
3.90
3.83
3.33
—
3.33
3.25
3.00
mg/1
0.88
0.69
1.50
—
0.47
0.43
0.71
mg/1
0.66
0.53
1.57
1.66
1.64
2.56
1.52
mg/1
0.18
0.14
0.54
0.76
0.63
0.72
0.68
mg/1
3.65
3.74
5.37
4.43
5.49
5.26
4.32
mg/1
0.89
0.56
0.82
0.43
0.10
0.47
0.58
      * Grab  sampling

-------
0>
     Table 4
     Nitrogen Concentrations, Mass Loadings  & Removal Rates*
     5/15/78 - 2/28/79
lentrat
mg/1
7.78
7.47
8.08
6.58
7.68
8.96
9.84
9.39
7.81
7.81
7.81
Influent
ion Mass Load
kg /day
2.49
1.74
1.87
2.27
2.31
2.94
3.48
3.54
2.94
2.94
2.94
Treatment
Time
days
5.51
9.83
6.43
2.27
6.09
5.30
4.70
4.30
1.93
3.04
4.30
Effluent
Concentration
mg/1
0.66
0.53
1.00
3.22
1.57
1.66
1.64
2.56
3.43
2.20
1.52
Mass Load
kg/day
0.14
0.07
0.15
0.94
0.31
0.37
0.41
0.70
1.11
0.66
0.41
Removal
Rate (%)
94
96
92
58
87
87
88
80
62
77
86
     * Adjusted for Evapo-transpiration Loss

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Table 5
Phosphorus Concentrations, Mass Loadings  & Removal Rates*
5/15/78  - 2/28/79
Influent

Concentration
mg/1
5.55
5.18
5.51
5.93
6.29
§ 4.74
6.72
5.88
4.99
4.99
4.99

Mass Load
kg /day
1.78
1.20
1.28
2.05
1.89
1.55
2.38
2.22
1.88
1.88
1.88
Treatment
Time
days
5.51
9.83
6.43
2.27
6.09
5.30
4.70
4.30
1.93
3.04
4.30
Effluent

Concentration
mg/1
3.65
3.74
4.95
5.31
5.37
4.43
5.49
5.26
4.75
4.61
4.32

Mass Load
kg/day
0.79
0.48
0.76
1.56
1.05
0.99
1.37
1.44
1.54
1.38
1.18

Removal
Rate (%)
56
60
41
24
44
36
42
35
18
27
37
* Adjusted for Evapo-transpiration Loss

-------
N)
-t*
00
        Table 6
        Pond  A Influent
        Loading  Rate:   435,102 Ipd
Month 1
1979 :
March
April
May
March-May
Pond A Effluent
TSS BOD5
Mean Std. Dev. Mean Std. Dev.
mg/1
3.33
4.27
9.33
5.64

Adjusted Treatment Time
March
April
May
March-May
3.20
3.33
4.00
3.51
mg/1 mg/1 mg/1
0.79 3.50 0.50
3.21 3.00 0.71
4.75 8.73 44.60
4.22 13.08 29.27

: 1.59 Days
0.92
1.19
0.63
0.81
Total N
Mean Std. Dev.
mg/1
10.12
5.75
42.74
22.41


3.71
5.75
0.89
3.51
mg/1
1.34
2.14
35.16
25.27


1.35
2.14
0.23
2.47
Total P
Mean Std. Dev.
mg/1
6.12
5.03
20.08
10.95


5.11
5.03
3.50
4.55
mg/1
1.46
1.38
12.26
9.35


1.06
1.38
0.99
1.17

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CO
       Pond B Effluent
       Adjusted Treatment Time:  2.37 Days
       Month
       1979

       March

       April

       May

       March-May
                   TSS
               Mean   Std. Dev.
               mg/1

               3.20

               3.20

               4.13

               3.51
         mg/1

         0.83

         0.65

         0.62

         0.83
                  BOD5
              Mean    Std. Dev.
              mg/1     mg/1
       Pond C Effluent
       Adjusted Treatment Time:   3.21 Days
March

April

May

March-May
3.13

3.87

4.47

3.82
0.80

0.80

0.52

0.92
Total N
Mean Std. Dev.
mg/1
2.18
3.08
0.89
2.05
1.49
1.71
0.74
1.31
mg/1
1.14
1.98
0.22
1.60
0.76
0.95
0.14
0.82
Total P
Mean Std. Dev.
mg/1
4.57
4.61
2.28
3.82
4.24
4.28
2.01
3.49
mg/1
0.77
1.13
0.70
1.23
0.74
0.84
0.88
1.35

-------
       Pond D Effluent

       Adjusted Treatment Time:  4.12 Days
to
Ul
o
Month
1979
March
April
May
March-May
TSS
Mean
mg/1
2.71
4.00
3.47
3.41
BODr
Std. Dev. Mean Std. Dev.
mg/1 mg/1 mg/1
0.80
0.89
0.50
0.99
Total N
Mean Std. Dev.
mg/1
1.13
1.30
0.76
1.01
mg/1
0.47
0.54
0.12
0.48
Total P
Mean Std. Dev.
mg/1
3.92
4.28
2.09
3.41
mg/1
0.71
0.78
0.80
1.40
Pond E Effluent
Adjusted Treatment Time: 5.11 Days
March
April
May
March-May
2.90
2.87
3.20
2.95
0.54 2.50 0.50
0.50 2.50 0.50
0.54 3.75 0.43
0.81 2.92 0.76
0.94
1.24
0.82
1.00
0.26
0.55
0.25
0.42
3.77
4.49
2.56
3.60
0.65
0.75
0.45
1.01

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        Table 7
        Total Loadings and Total Effluent Content  & Removal Rates
        March 1 - May 31, 1979
                         TSS
BODC
Total N
Total P
CJI
Sampling
Point
Influent
Pond A
Outflow
Pond B
Outflow
Pond C
Outflow
Pond D
Outflow
Pond E
Outflow
kg /day
2.45
1.32
1.23
1.24
1.02
0.80
Removal
Rate
%
—
46
50
43
58
67
Removal
Rate
kg/day % kg/day
56.62 — 9.75
1.32
0.72
0.42
0.30
0.85 98 0.27
Removal
Rate
%
—
43
93
96
97
97
kg/day
4.77
1.71
1.34
1.13
1.02
0.98
Removal
Rate
%
—
64
72
76
79
79
Adj. Tre
Time (D
—
1.59
2.37
3.21
4.12
5.11

-------
Figure 1
Hyacinth  System Schematic

                       Pond
                         '£'
Pond
 'D1
                                _/ V.
                        Pond
                         'A'

                                         Pond
                                           'C'
                                          Pond
                                           'B'
                                       252

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                                                  Water hyacinth covered ponds
                                                  operated by  the Coral Springs
                                                  Improvement  District.
                                  6/14/78
Harvesting water hyacinths with
a weed-bucket equipped, truck
mounted drag line.
                                        Water hyacinths being placed on
                                        a concrete solar drying pad.

-------
       Figure 2
NJ
Ul
                    Total N
                    (Mg/l)
                                                 SCATTERGRAM
                                                                           8     9      10
                                                                               Time  (Days)

-------
Acknowledgments

     Dr. B. C. Wolverton, National Space Technology Center, Bay
St. Louis, Miss., whose pioneering work in water hyacinth waste-
water treatment led to the inception of Project Hyacinth, for
his guidance and suggestions.

     Dr. William Duffer, Robert Kerr Environmental Research
Laboratory, Ada, Oklahoma, for his interest, guidance and
suggestions.

     Dr. Ronald F. Lewis, Municipal Environmental Research Laboratory,
E.P.A., Cincinnati, Ohio for his interest and suggestions.

     Dr. Thomas deS. Furman, et al., Department of Engineering
Science, University of Florida, Gainesville, Florida, whose studies
of nutrient removal by water hyacinth provided data for engineering
design of Project Hyacinth.
                                      255

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     WATER HYACINTH WASTEWATER TREATMENT SYSTEM
     AT WALT DISNEY WORLD

     Andrew P. Kruzic, Reedy Creek Utilities Company,
       P.O. Box 40, Lake Buena Vista,  Florida  32830
INTRODUCTION

     Pioneering scientific studies sponsored by the National Aero-
nautics and Space Administration and performed by the National Space
Technology Laboratories at Bay St. Louis, Mississippi, have shown that
vascular aquatic plants, such as the water hyacinth (Eichhornia
crassipes), can be remarkably effective in the removal of nutrients
lind toxic materials from municipal and industrial sewage.  The potential
for utilization in both secondary and tertiary wastewater treatment
systems has been demonstrated (refs. 1 and 2).  In addition, the
prospects for developing useful products from the harvested plant are
promising (ref. 3).  Although these studies have demonstrated feasibi-
lity, the ultimate commercialization of a water hyacinth wastewater
treatment system requires its comparative evaluation with alternative
wastewater treatment systems, both economically and with regard to
typical water quality standards and requirements.

     A study performed by the Battelle Columbus Laboratories (ref. 4),
addressed the potential market for such wastewater treatment systems.
They found that the lack of existing systems and verified design data
was a major obstacle to accomplishment of their study.  However, they
concluded the following:

     o    Under ideal conditions, water hyacinth based systems can be
          designed which are highly effective in tertiary treatment of
          municipal wastewater.

     o    Operationally verified  design parameters are needed for
          hyacinth systems.
                                      257

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     o    For municipal systems designed to meet stringent effluent
          standards, hyacinth-based systems offer a possibility for
          appreciable cost savings over competitive processes in
          construction of completely new facilities.

     o    The cost advantage will be greater in many types of upgrading
          activities.

     o    Considering only the southern Florida municipal application,
          it appears that a reasonable estimate of the savings offered
          by hyacinth systems is $165 million over the next 25 years,
          with the largest share of this within the next decade.

     o    Hyacinth treatment systems are in a comparatively early
          stage of development.  It is quite possible that further
          engineering will improve the competitive position of
          hyacinth systems.

     o    Present information on the characteristics of hyacinth
          systems is not adequate to bring about implementation on a
          significant scale.  If, however, the potential advantage
          suggested by this analysis can be demonstrated and verified
          in actual use, market penetration should be rapid, at least
          in southern Florida.

     As a result of the Battelle and NASA work, WED Enterprises, a
subsidiary of WALT DISNEY PRODUCTIONS, was sufficiently interested in
the potential for such a system to further investigate its feasibility
by hcsting a meeting of technical experts in July 1976 to review a
plan for a pilot project (ref. 5).  The consensus opinion was that the
project had sufficient merit that WED should proceed with a pilot
plant system.  This pilot plant, sized for 50,000 GPD, would be the
necessery precursor to the design and economic assessment of a proto-
type 1 MGD system.

     WED acted on this recommendation by forming a team of participants
interested in the further development of this technology and by struc-
turing a program that addresses the complete system; i.e., ultimate
disposal of the hyacinths as well as wastewater treatment.  The program
was submitted to EPA for grant funding and was approved August 1,
1978.  The original participants included:

     o    Aquamarine Corporation, the nation's largest producer of
          aquatic plant harvesting equipment.  They designed and built
          the harvesting system for the project.

     o    Boyle Engineering, a consulting engineering firm that designs
          advanced wastewater treatment systems.  Headquarterd in
          California, the company has branch offices in the Gulf Coast
          area as well as in Florida, the market areas for the hyacinth
          system.  Boyle in Orlando participated in the preliminary
          design phase and produced the final plans and specifications.
                              258

-------
     o    Environmental Protection Agency through the  Robert S. Kerr
          Environmental Research Laboratory in Ada,  Oklahoma is
          acting as the lead federal organization in this  project
          and is supervising the spending of grant funds.

     o    National Aeronautics and Space Administration  through the
          National Space Technology Laboratories  is  providing both
          expert advice and grant funding for the project.

     o    Reedy Creek Improvement District is a special  legislative
          district in Florida which includes all  of  WALT DISNEY WORLD.
         Its legislative charter calls for the district  "to promote
          and create favorable conditions for the development and
          practical application of new and advanced  concepts."  The
          grant request to EPA was made through RCID which provides
          budget management and water quality analysis for the project.

     o    United Gas Pipe Line Company, the major subsidiary of United
          Energy Resources, Inc.  United is expanding into areas
          intended to complement its natural gas transmission business,
          particularly the search for alternate sources  of supply.
          U.C.P.L. has funded extensive research by the  Institute  of
          Gas Technology and has also provided funds for this project.

     o    Walt Disney Productions through its subsidiaries WED
          Enterprises and Reedy Creek Utilities Company developed  the
          project from conception and is providing program management,
          engineering and operations personnel.

     Recently additional participants have joined the project:

     o    University of Arizona's Environmental Research Laboratory
          has done considerable research in hyacinth production and
          will perform supporting studies for the project in the areas
          of growth optimization and nutrient requirements.  They are
          also involved in the design of a cover over one channel.

     o    Department of Energy through an interagency agreement with
          the EPA will also support the project financially which will
          allow for a broadening of the project objectives.

     o    Gas Research Institute will fund extensive studies in methane
          generation with various feedstocks and  sewage sludge from
          WALT DISNEY WORLD.
Objectives
            &  Schedule
     The  objectives as  stated  in the grant proposal were broad but
 imple:   (1)  demonstrate  a hyacinth system capable of meeting tertiary
    secondary wastewater  treatment standards,  (2) demonstrate an energy
                                          259

-------
conservative wastewater treatment system, (3) determine the optimum
system performance characteristics and (4) determine the economics of
a hyacinth based system.  None of these objectives have changed but
there has been a. shift in emphasis from tertiary to secondary treatment,
A new objective has also been added with the recent addition of DOE
and GRI as participants in the project.  It is to experiment with
means of increasing biomass production and converting biomass into
energy.

     August 1, 1978 marked the beginning of a four year project.  The
final plans and specification were completed by mid November and
construction began February 1, 1979.  The end of construction on
May 11, also marked the beginning of operation.  Two months were
allowed for seeding and establishing a hyacinth crop.  On July 16,
1979 the project started into the Preliminary Operation Phase which
will last three or four months (see figure 1).  The objectives of
the Preliminary Operation Phase are to quickly learn if there is an
advantage to operating the system at a low water depth of 15" or a
relatively high depth of 36" and if a rapid harvesting rate of twice
per week is preferred over a slower rate of twice per month.

     After the Preliminary Operation Phase two, one year periods, will
follow of relative steady state operation.  By the start of the first
winter season a cover will be added over one of the channels.  The
influent to the hyacinth ponds shall be primary effluent the first year
and secondary effluent the second.  During the steady state periods
the three channels will be used to determine the differences between
covered and uncovered channels and between end and side harvesting.
The optimum water depth and harvesting rate determined during the
Preliminary Operation Phase will be used during the steady state period
and will not be changed unless supporting studies dictate a change.

     After two years of steady state operation, the remaining eight to
nine months of the project will be devoted to experimentation with
growth optimization.

Project Components

     The project can be broken down into several systems or components:
(1) Production System, (2) Harvesting System, (3) Composting System,
(4) Monitoring Systems and (5) Supporting Studies.  Components of the
production system include the three 1/4 acre production channels, the
system piping, utility tie-ins hydraulic control devices, and pumping
stations.

     Two submersible pumps,  one in the primary clarifier effluent
channel and the other in a filter pump wetwell of the existing RCID
Wastewater Treatment Plant provide the system with primary and/or
secondary effluent.  An industrial water supply line has also been
constructed to the project.   The three pond influents are metered into
the channels through a flow splitter system.   Industrial water and
                              260

-------
                                   Figure 1

                                PRELIMINARY OPERATION PLAN
Channel
*Preliminary
  Operation
   3-4 Mo.
Steady
State
1st Yr.
Steady
State
2nd Yr.
  Other
Operation
   9 Mo.
           I1 Depth
           2/Week Harvest
           Primary  Effluent
           Parallel Flow
           No Cover
                21 Depth
                I/Week Harvest
                Primary Effluent
                Parallel Flow
                No Cover
               2 '  Depth
               Control
               Second. Effluent
               Parallel Flow
               No cover
           3'  Depth
           2/Week Harvest
           Primary  Effluent
           Parallel Flow
           No Cover
                2'  Depth
                I/Week Harvest
                Primary Effluent
                Parallel Flow
                No Cover
               2' Depth
               I/Week Harvest
               Second. Effluent
               Parallel Flow
               No Cover
           3' Depth
           2/Month Harvest
           Primary  Effluent
           Parallel Flow
           No Cover
                2'  Depth
                I/Week Harvest
                Primary Effluent
                Parallel Flow
                Cover
               2'  Depth
               I/Week Harvest
               Second.  Effluent
               Parallel Flow
               Cover
                     Possible Operations

                       Series Flow

                       Maximum Growth
                       with High
                       Nutrients and
                       Rapid Harvest

                       More Experience
                       with Harvesting

                       Nutrient
                       Addition

-------
secondary effluent are controlled by turbine meters and control valves.
Control of the primary effluent is by weirs and control valves.  The
flow splitter system allows one, two, or three influents in the three
channels.  The channels are also interconnected hydraulically to provide
for a variety of experimental modes of operation.  (See Figure 2).

     The walls of the channels were constructed of reinforced concrete
block on a cast-in-place, reinforced concrete foundation.  The channels
(29' x 360') were lined with 20 roil PVC and tacked to the top of the
walls with lumber.  PVC booms are tied off to cleats along the top  of
the channel walls with lumber.  PVC booms are tied cff to cleats along
the top of the channel walls and act as a corral preventing the hyacinths
from packing together at one end of the channel.  The water level in the
channels is adjustable by use of effluent weirs.  The water depth can be
maintained at 15, 24, or 36 inches.  Each of three channels incorporates
the capability to be operated independently and at varied depth if
desired.

     The production system is designed hydraulically to handle flows up
to 200,000 gpd but will probably operate at 50,000 gpd.  The flow rate
will be set during the fall or spring seasons at the maximum flow rate
which will meet the given effluent standards.  The system has been
designed and built to provide the needed flexibility and experimental
control and not as the least expensive way to grow hyacinths.

     A cover over one channel will be constructed by December of 1979.
It is currently in the design phase and may include the capacity for
C0~ enrichment studies.

     There are three pieces of equipment used for harvesting:  (1)  a
front end loader, (2) a double belt conveyor-chopper and (3) a forage
wagon.  All mechanisms in the system are powered by hydraulic motors
connected to the hydraulic pump in the front end loader.  The harvesting
system is designed with a capacity of 50 tons per hour, far in excess
of the system requirements.

     Harvesting is accomplished by pushing the hyacinths onto the
primary conveyor with a long handled hook.  At the end of the primary
conveyor a flail chopper cuts the plants into smaller pieces.  The
secondary conveyor loads the chopped plants into the forage wagon which
has a live bed for ease of loading and unloading.  With this method a
thick 900 sq. ft. interwoven niat of mature water hyacinths can be
harvested in approximately one hour.  Set up and take down time is  also
approximately one hour.  These times should drop as experience is gained
with the system.

     The three channels will be divided in cells 60'  long x 29' wide
by floating booms.  The harvesting system is completely mobile and  can
accomodate harvesting both from the sides and ends of the channels.
                               262

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           L:
           r
J
                                                  EFFLUENT
       ru
INFLUENT
                    SERIES  (PLUG) FLOW
                                                                                                                                             EFFLUENT
                                                                                           INFLUENT
                                                              TWO  INFLUENTS. PARALLEL  FLOW
                                                  EFFLUENT
INFLUENT
                      PARALLEL FLOW
                                                                                                                                             EFFLUENT
                                                                                           INFLUENT
                                                                     TWO INFLUENTS
                                                            ONE  IN PARALLEL AND  ONE  IN SERIES
                                             J
                                                 EFFLUENT
INFLUENT
             ONE  IN  PARALLEL AND TWO  IN SERIES
                                                                                                                                             EFFLUENT
                                                                                           INFLUENTS
                                                                   THREE INFLUENTS
                                                         Figure  2
                                                          SYGTD-l MODES

-------
 One  channel will be covered during the winter and may require end
 harvesting only.  During the steady state operation, a second uncovered
 channel would  then be end harvested for comparison with the covered
 channel and third channel could be side harvested for comparison with
 the  second.  In all three channels the same harvesting rate, total
 hyacinth  coverage and individual cell coverage would be maintained.
 The  floating booms will be used to push the hyacinths in each cell into
 a uniform density, thereby allowing measurement of the hyacinth covered
 area before and after harvesting.  Once a week a 5 square foot area of
 plants in each cell would be weighed to get the hyacinth density.

     The  composting system is a windrow system utilizing a composting
 pad  and a front end loader.  Once the forage wagon is full, it is
 moved to  the composting pad and unloaded by means of the live bed.
 All  hyacinth harvested that day are put into a pile.  A new pile will
 be turned three times during the first week, and once per week for the
 remaining five weeks.  Temperature and free moisture will be monitored
 in the piles for composting control.  The desired values are 50-60
 percent moisture and 140-150° F.  The compost product will be analyzed
 quarterly and  will be given to the W.D.W. Grounds Maintenance Department
 for  use on their ornamental tree farm.

     The  monitoring role can be divided into two functions:  (1) baseline
 date acquisition and (2) intensive studies.  The baseline monitoring
 program will provide the long term data on how well the hyacinth system
 operates  and what can be expected from it, while the intensive studies
 will provide the answers to specific questions.

     Table 1 is a summary of the baseline monitoring program.  The
 operators are  responsible for recording the daily environmental condi-
 tions such as  water and air temperature while chemical analysis of the
 pond influent  and effluent is performed twice per week by the RCID
 laboratory.  Bi-weekly chemical analysis is considered sufficient  in
 light of  the long hydraulic detention times in the channels (7 to  15
 days).

     The  monitoring system includes equipment, such as four automatic
 samplers  and an automatic analyser, as well as a record keeping system.
The  record keeping system is set up on a daily, weekly,  monthly and
quarterly basis depending on the parameter being analysed or recorded.
The  daily date summaries kept by the project operator includes flows,
water temperatures,  dissovled oxygen concentrations and other environ-
mental information.   The weekly data summaries include laboratory
analysis,  a summary of the daily records and the composting and har-
vesting data.   Similarly the montly records are a summary of the weekly
data summaries.

     In order   to keep a record of hyacinth production for harvesting
and data analysis purposes it was necessary to devise a method for
determining hyacinth density.   The method involves using the floating
booms to get a uniform density and the percentage of water surface
area covered with hyacinths.   A five square foot area is segregated
                              264

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BASELINE MONITORING
MEASUREMENT PERFORMED BY
Flow WWTP Oppral-or
1^0 temperature " "
pH
DO
Humidity "
Air tpmpprature
Rainfall
Solar Insolation CEP
pH I, ah
TSS
TDS
BOD
TOD
10
g> TOC
NH3 - U
Orq - H
Nitrite - N
Nitrate - M
Ortho - P
Totnl P
Total A I ka 1 ini ty
Tota 1 Co] iform
LOCATION FREQUENCY
UE 3/day
1M&E 3/day
1H&E 3/day
1M&E 3/day
Pond Vicinity Continuous
" " Continuous
" " Continuous
CEP Continuous
1SE 2/wenk
2/week
2/week
" 2/week
" 2/we«k
2/wopk
2/v;fok
" 2/wpek
2/wrpk
'* 2/wppk
" 2/woek
" 2/wPok
2/wppk
" 2/wook
REPORTED
IRE ; Daily Avoraqp
1MSE; Daily Averaye
IMS?;; Daily Average
1M&E; Daily Average
Low/High; Daily Average
Low/High; Daily Averagp
Daily
Btu/day - m2















-------
 from the rest of the uniformly bunched hyacinths by using a tool
 similar to a cookie cuttler.  The segregated hyacinths are then moved
 into a basket attached to a hanging scale and are weighed.  The weight
 divided by 5 square feet gives the density of the hyacinths in that
 area and using the densities of the other areas, the weight of the
 whole crop can be established.

      The major pieces of monitoring equipment are (1) an automatic
 analyzer, (2) four refrigerated automatic samplers, (3)  moisture and
 temperature probes for the composting operation, (4) flow meters and
 (5) meteorological instruments.

      The RCID laboratory has purchased an automatic sampler in connec-
 tion with the project to perform daily water quality analysis and the
 intensive studies.  This piece of equipment augments a very well
 equipped lab which includes an atomic absorption spectrophotometer
 and gas chromatograph.

      Three composite and one discrete automatic samplers are used at
 one influent and three effluent sampling points.  The samples are
 collected over a 24 hour period but are not proportional to flow.   A
 flow meter has been purchased which when hooked up to one of the
 composite samplers will give a proportional to flow sample.

      The monitoring of the composting operation is done  with two
 pieces of equipment, an insitu moisture meter and a temperature probe.
 The control of the operation and the determination of the end of the
composting process will be based on free moisture and temperature.

      Flow in and out of the ponds will be recorded from  turbine meters
 and with rainfall data will be used to determine evapotranspiration
 which may be very large in hyacinth systems.

      The meteorological instruments include a pyranometer for solar
 insolation measurement and an air temperature and humidity meter and
 recorder.

      The intensive studies will include any monitoring requirements
 beyond the baseline monitoring program.   Some studies will answer  very
 specific questions while others provide essential information to the
 data base of the project.   The intensive studies will include:

      (1)  Comparison of proportional to flow samples with regular
           composite samples.

      (2)  Determination of day to day variations and hour to hour
           variations in effluent BOD,  SS,  N,  P valves.

      (3)  Determination of BOD,  SS,  N,  P channel profiles.

      (4)  Performing laboratory water quality analysis quarterly
           for metals,  pesticides,  etc.
                               266

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     (5)  Performing plant characterization quarterly;  relate  to
          size to plant and location in pond.

     (6)  Performing compost characterization  quarterly.

It may be necessary in the future to incorporate some  of  the quarterly
analysis into the baseline monitoring program.

     The supporting studies are a very important part  of  the overall
project.  The objective of the supporting studies is to provide informa-
tion through laboratory scale research which could influence the
operation of the project.  Specific areas of needed research include
growth optimization through micro and/or macronutrient addition,  optimum
harvesting schedule, duckweed performance during hyacinth dormant
periods and energy conversion.

     The University of Arizona has had for some time an extensive
research program with water hyacinths.  They have joined  the project  as a
participant and will perform many of the supporting studies.   Mr. John
Groh of the Environmental Research Laboratory  at the University of
Arizona is also involved in the design of the  cover.

     The energy conversion supporting studies  will be  performed through
the Gas Research Institute.  Anaerobic digestion performed in  the lab
of hyacinths, sewage sludge and mixtures of the two will be the subject
of the first studies.

Data Analysis

     Water quality analysis was started halfway through the two month
crop establishment period.  Secondary effluent was used during this
period because of its high nutrient content and low-potential for causing
anaerobic conditions in  the ponds.  On May 14, each of the three channels
was seeded with 30 feet  of water hyacinth, roughly 10 percent of the
total surface area.  In  two months the coverage was 100 percent which
gives a doubling time of approximately two weeks.  With full coverage,
the pond was meeting the tertiary effluent standard of 5 mg/1 BOD,
5 mg/1 SS, 3 mg/1 T.N.,  but was not meeting the phosphorus standard
of 1 mg/1 T.P. (see Table 2).  However, this data is not sufficient to
make any conclusions about the systems effectiveness in the tertiary
treatment mode.

     On July 16, 1979, the pond influent was switched  to primary effluent
and the Preliminary Operation Phase was started.  The  summary of data
collected during the month of August  is presented in Table 3.   The raw
influent to the Reedy Creek Improvement District  (RCID) treatment plant
averaged 200 mg/1 SS and 300  mg/1 BOD during August.   The pond
effluent averaged 22.9 mg/1 SS and  27.9 mg/1 BOD.  Taking into account
a reduced effluent  flow  rate  due  to evapotranspiration the combination
of primary clarification and  hyacinth treatment does meet the secondary
treatment standard  of  90 percent  removal of BOD and SS.  However, the
data  is not sufficient to make any  further conclusion  at this time due
to the  limited time of operation.
                                      267

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                              Table 2

                     HYACINTH PROJECT DATA SUMMARY



                          WEEK ENDING 7/15/79
     PARAMETER


  1. FLOW (gpd)

  2. pH


  3. TSS (mg/1)


  4. BOD (mg/1)


  5. NH3-N (mg/1)


  6. ORG.-N  (mg/1)


  7. N03-N  (mg/1)


  8.  TOTAL-N  (mg/1)


  9.  ORTHO-P  (mg/1)

10.  TOTAL-P  (mg/1)


11.  H2O TEMP.  (°C)


12.  H2O D.0  (mg/1)


13. AIR TEMP.  (°F)


14. HUMIDITY  (%)

                       2
15. INSOLATION  (BTU/ft -day)

Summary based on one  set  of  data
SECONDARY
EFFLUENT

 50000

 6.4

 10.0

 16.0

 11.1

 6.87

 0.20

 18.17

 3.76

 4.50

 27

 1.6

 83

 76

1170

points.
POND
EFFLUENT
 6.4

 2.0

 3.0

 0.08


 1.27

<0.01

 1.35

 2.15

 2.18
                               268

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                             TABLE 3

                   HYACINTH PROJECT  DATA SUMMARY



                               AUGUST  1979
     PARAMETER


 I.  FLOW (gpd)


 2.  pH

 3.  TSS  (mg/1)


 4.  TDS  (mg/1)


 5.  BOD  (mg/1)


 6.  NH3  -  N (mg/1)


 7.  ORG. - N  (mg/1)


 8.  NO3  - N  (mg/1)


 9.  TOTAL  - N (mg/1)


10.  ORTHO  - P (mg/1)


11.  TOTAL  - P (mg/1)


12.  ALK.  (mg/1)


13.  TOTAL  COLI.  (mpn/lOOml)


14.  H20 TEMP.  (°C)


15.  H20 D. 0 (mg/1)


16.  AIR TEMP  (°F)


17.  HUMIDITY  (%)

                       2
18.  INSOLATION  (BTU/ft -day)


Summary based on  8  sets of data
*Flow based on one  week's data.
PRIMARY
EFFLUENT
50000
6.9
83.2
285
160
18.38
9.10
0.01
27.49
4.61
6.20
122
1.05 -10
27
0.6
81
83
1300
points .
POND
EFFLUENT
42000*
6.9
22.9
237
27.9
14.76
7.18
0.01
21.95
4.13
4.80
147
B
1.43-10






                                    269

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     The first compost piles were started August 8.  The data on the
composting operation indicates that water does need to be periodically
added to keep the free moisture content up to 50 percent.  No odors
are detectable at the site which also indicates that more water can be
added.  The temperature of the piles has not reached the desired level
but it is not clear whether this is due to improper temperature measure-
ment or lack of sufficient free moisture.  A new temperature probe is
being acquired for the composting operation.

     Data analysis is considered a very important part of the project
and in the future loading rates, detention times, hyacinth growth,
nutrient mass balances, removal rates and removal efficiency will be
calculated as part of the data analysis.  The most important factors
are the appropriate removal rates which will be correlated with loading
rates, hyacinth growth and environmental conditions.

SUMMARY

     In general all of the components of the project are operating as
planned but there have been problems.  For example, when the ponds were
first seeded the hyacinths were hand picked and placed into the channels.
This was too slow, so a backhoe was used to finish the seeding.  This was
a mistake because a great deal of dollarweed and grass was brought in
with the hyacinths.  Some of the unwanted species were removed but total
segregation was not possible.   The unwanted plant species were harvested
out of the system only after much effort.

     The only major concern at this time is whether or not the system
can effectively handle primary effluent.  The dissolved oxygen concen-
trations are very low,  floating sludge in the open areas has appeared
and there are many fly larvae where the ponds once flourished with
thousands of mosquito fish.   Fortunately mosquitoes have not been a
problem so far.

     In summary,  the hyacinth project at WALT DISNEY WORLD is still in
the process of start up.   The scope of the project is quite large and
there are many details to be worked out.  The system is unique in its
attempt to provide all the data needed by engineers to design a water
hyacinth wastewater treatment system.
                              270

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    REFERENCES
1.  B.  C.  Wolverton,  R.  C.  McDonald, J. Gordon, Water Hyacinths
    and Alligator Weeds  For Final Filtration of Sewage.
    TM-X-72724.'"
2.  B. C.  Wolverton,  R.  C.  McDonald, Water Hyacinths For Upgrading
    Sewage Lagoons To Meet Advanced Wastewater Treatment Standards:
    Part 1.RM-X-72729, October,1975.


3.  B. C.  Wolverton,  R.  C.  McDonald, Application of Vascular Aquatic
    Plants For Pollution Removal, Energy and Food Production In a
    Biological System.  TM-X-72726, May, 1975.


4.  A. C.  Robinson, H. D. Gorman, M. Hillman, W. T. Lawhon, D. L.
    Masse  and T.  A. McClure, An Analysis of The Market Potential
    of Water Hyacinth -  Based Systems for Municipal Wastewater
    Treatment.  January  31, 1976.


5.  WED Enterprises,  EPCOT Technology Meeting - Sewage Filtration
    and Energy Production Using Water Hyacinths.July 1,1976.
                               271

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    UTILIZATION OF WATER HYACINTHS  FOR CONTROL OF
    NUTRIENTS IN DOMESTIC WASTEWATER — LAKELAND, FLORIDA
    E.  Allen Stewart III,  P.E.,               Dawkins & Associates, Inc.
    Environmental Specialist/Engineer        Orlando, Florida
    The use of water hyacinths (Eichhornia crassipes)  for removal of
nutrients and solids during a demonstration project in Lakeland,
Florida indicates that removals are as a result of more than hyacinth
uptake.  Therefore, if design of a hyacinth system is  based upon the
uptake and growth kinetics of the plants during cool weather periods,
it appears that an ample safety margin can be maintained.  The hyacinth
growth rates were found to be similar to those found in other studies.
A first order design equation based upon the Monod concept using total
nitrogen as the limiting nutrient is presented.  Other aspects of the
hyacinth system such as harvesting, crop processing, and marketing have
been investigated, but are still in need of additional field work before
maximum effectiveness is realized.
INTRODUCTION

    Utilizing local funds, the City of Lakeland and Polk County,
Florida have implemented a demonstration project intended to investi-
gate the possibility of utilizing water hyacinths for removal and
recovery of nutrients from secondary effluent prior to discharge into
the nearby Peace River System.  This demonstration project presently is
over half completed.  It has resulted in the development of a better
understanding of the potential of hyacinths in nutrient removal.  It
has also revealed that these systems can be successful only if directed
by an intensive and effective management program designed for efficient
crop handling, selective harvesting, and rapid processing and movement
into the selected market.
SYSTEM DESIGN

    While there are presently a few water hyacinth systems in operation
throughout the Southern U.S., there are several factors related  to  the
Lakeland situation which make its design considerations somewhat
                                       273

-------
 unique.   First of all,  the nutrient removal requirements  are extremely
 stringent—1.5 mg/l-TN  and 0.4 mg/l-TP.   Secondly,  the concept  is
 being groomed to become part of a regional 201  plan,  meaning the size
 of the system could be  as  large as 49,200 cubic meters/day  (13  mgd).
 This  means  that unlike  smaller systems,  there will  be a most urgent
 need  to  handle the harvest quickly and efficiently.   In essence, the
 Lakeland Demonstration  Project was intended to  investigate  the  poten-
 tial  of  water hyacinth  treatment as a large scale treatment methodology.
    The  physical design of the demonstration ponds  as shown in  Figure 1
 is intended to allow the operator some flexibility  in manipulating such
 critical parameters as  depth,  pollutant  and hydraulic loading,  and
 retention time.   The three-ponds-in-series concept  allows easier
 assessment  of productivity responses to  changes in  water  quality.
    Three harvesting channels  intended to accommodate a Hidrostal  E5KL
 solids pump or a aqua-guard self-cleaning bar screen  were included as
 part  of  the design.   Both  of these two harvesting possibilities showed
 potential for removing  large quantities  of material at a  low energy
 and labor input.   An efficient harvesting system is one necessary
 requirement for a large scale  hyacinth system.
PROJECT GOALS

    The Lakeland demonstration project, as noted, was intended to
review all aspects of water hyacinth treatment, and to provide some
guidance in developing a design for a large scale system.  Basically,
there are three major design questions which must be confronted.
        At what rate and by what mechanism(s) do hyacinths remove
nutrients, and what parameters control these rates?
        Can the hyacinths be effectively harvested, processed and
dried without over-escalating operating costs?
        Are there any marketing potentials for water hyacinths, and
to what degree can the sale counter operating costs?
DESIGN CONSIDERATIONS FOR NUTRIENT REMOVAL

    Construction of the three, 0.405 hectare (one-acre) lagoons as
shown in Figure 1 was sufficiently completed by 12/6/78 to permit
filling.  This was done through a 6-inch siphon line from the eastern-
most secondary clarifier at a rate of 0.719 cubic meters/sec. (190
gpm).  By 12/20/78, the ponds were completely full.  At this time about
0.91 metric tons (1 ton) of hyacinths were introduced into each pond.
This represented an approximate surface area of 23 square meters/pond
(250 square feet) or a 0.5 percent coverage of the total surface.
    Productivity was monitored by setting a 0.093 square meter (1 sq.
ft.) chamber within each pond, seeding it with a small plant and
measuring weekly growth changes on a wet weight basis.  Later in the
program dry weight density estimates from random samples will be used
to project productivity.
    As is shown in Figure 2, there is a good exponential relationship
between change in wet weight and time.  Also, there is a notable change
in the rate rf growth between the different ponds.  It was also noted
                               274

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           GLENDALE  STREET
  LAKELAND
  WASTE  TREATMENT
  PLANT
,  EXISTING
/  SECONDARY
   CLARIFIER
 6  PVC INFLUENT LINE
        i
1
                           i
                   HYACINTH
                     PONDS
           EXIST.
         INCINERATOF

Figure 1 :
                   Site Plan for Water Hyacinth
                   Treatment Demonstration
                   Project -- Lakeland, Florida
             275

-------
                              POND 1
                        y = 14.51 e
                              r = 0.98
                                  0.44 301 x
                       y = 16.124 e
                              r = 0.98
  TIME IN WEEKS
     Figure 2:    Growth Kinetic Equations for
                Lakeland Hyacinth Study
276

-------
that the chlorophyll content and general health of the plants declined
from Pond 1 to Pond 3.  This change was interpreted as a nutrient or
vitamin deficiency.  Nitrogen, carbon, and phosphorus levels were
observed to be adequate in all three ponds.  Further investigations
showed no changes in potassium or magnesium.  Iron, however, was noted
to decline from 0.125 mg/1 to 0.05 mg/1 throughout the system.  This
latter concentration is low even for many natural waters in Florida.
Because of this, and because water hyacinths are known to effectively
take up iron, it was decided that iron might be the present limiting
nutrient.  To compensate for this deficiency, ferrous sulfate was
added to the ponds at such a rate that the concentration of iron was
maintained near 0.30 mg/1.  This replenishment resulted in a general
cessation of this chlorosis.
    The equation, as shown in Figure 2, for Pond 1, can be modified
if it is realized that the constant 14.51 represents the initial
standing crop.  If this is converted to a variable (Z), this new equa-
tion can be utilized as a design equation for winter conditions as
follows:

                         y  = Ze°-44301*

        where       y   =   wet weight produced (metric tons)
                    x   =   time in weeks

Based upon the literature it may be legitimately assumed that dry weight
is 0.05 y, total P by dry weight is 0.5 percent, and total N by dry
weight is 4.0 percent.  Average winter air temperature is 14.4°C
(58°F) as indicated in Figure 3.
    The desired winter standing crop can now be determined by equalibra-
ting with the incoming load of nutrients.  For 378.5 cubic
meters/day (100,000 gpd), using 25 mg/l-TN and 6 mg/l-TP, the load  is
equal to 9.53 kg/day  (21 Ibs./day) nitrogen and 2.27 kg/day  (5.0 Ibs./day)
phosphorus.  This  is equivalent of 756 kg/day  (16,667 Ibs./day) of wet
hyacinths or 52,967 kg/week  (116,667 Ibs./week) of wet hyacinths.   This
value can be seen  to be equal to Y-Z or AZ.  This allows the design
equation to be expressed as  follows:
                Y-Z
AZ = Ze0.44301x_z = 52>967 kg
    Setting x as one week,  it  is  found  that  the  desired  standing crop
 (Z) is 95,027 kg (209,310 pounds  wet weight.   Using a  desired plant
 length of 64-76 cm  (25-30 inches) and a density  of  225 metric tons/ha
 (100 tons/acre) (see Figure 4), the indication is  that 0.43 ha (1.06
 acres) of hyacinths at a wet density of 225  metric  tons/ha would handle,
 in the winter, 378.5 cubic  meters/day (100,000 gpd)  of secondary
 effluent, using a weekly growth rate coefficient of 0.44301.  This
 amounts  to about 11.8 hectares/million  cubic meters daily (11 acres/
 mgd).  Considering  only 75  percent coverage  and  anticipating a decline
 in growth rates in  the latter  stages, it  appears that  21.5 hectares/
 million  cubic meters daily  (20 acres/mgd) would  be  more  realistic.
 (This corresponds to a growth  rate coefficient of  about  0.33).
    With this density and acreage the incoming nutrient  load would
 theoretically be reduced to negligible  levels.  Unfortunately, the
                                       277

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10
                                                                                                          TEMP. (°C)
                                                                                                               (32.2)
              JANUARY 1979
FEBRUARY 1979
       MARCH, 1979
                                                                                                                  -4)
                                                                                                                (-1.1)
                                                                                                                (-6.7)
                                                           (-12.2)
  15     10     15    20     25    30l       5      10     15    20
                     2'5   '

                     Figure 3:
5
15    20     25
                                                                                    Temperature Profiles at Lakeland
                                                                                    WWTP During Phase 1 of t.'ie
                                                                                    Hyacinth Demonstration Project

-------
     .200
      448)
LU
DC
O
og
2 O
  K
UJ
Q
I-
LU
      150
      336)
         _
      224)
      50
     (112)
    O
 15
(38.1)
  30
(76.2)
  45
(114.3)
                           TOTAL LENGTH IN INCHES
                                              (CM)
                                        Figure 4:   Estimated Hyacinth Density
                                                  Based Upon Plant Length
                                                  [Wolverton. 1977]
                                        279

-------
nitrogen to phosphorus ratio of  the plant material  is lower  in  the
wastewater than in the plant material.  This means  that at some point
nitrogen may become a limiting factor and productivity will  decline
much  in the way when iron was noted to be deficient in Pond  3.   The
question is, at which concentrations will this occur?
    Musil and Breen (1977), two  South African researchers, evaluated
the growth kinetics of water hyacinths through the  Monod limiting
nutrient enzyme equation —
                        U = U  ( S )  .
                               K +S
                               s
        where   U   =   specific growth rate
                U   =   maximum specific growth rate
                S   =   limiting nutrient concentration
                K   =   half saturation constant;  i.e. when U = 0.5U.
    This equation is similar to that used in determining bacterial
growth kinetics in activated sludge.  In thei.r investigations, Musil
and Breen  (1977) determined that nitrate (NO.,) was the limiting  growth
factor.  In fact, they implied that other nitrogen forms are not
utilized by the hyacinths.
    "NH^-N-supplied in culture, however, had no effect on growth.  This
is in agreement with Sculthorpe (1967) who suggested that the NH+  ion
does not act as a nitrogen source for hyacinth plants."
    Unfortunately, the concept of nitrate  as being the most important,
and perhaps the only nitrogen source for hyacinths, does not agree with
data collected so far in the Lakeland study. For example, Musil  and
Breen  (1977) projected that Kg for NOj is 21.74 mg/1 as NO— or 4.91
mg/1 NO— as N.  The concentration in Pond 1 during this period of
testing averaged 0.25 mg/1 NO  as N, while in Pond 3 it averaged 4.0
mg/1 NO--N.  Applying this information, to the Monod equation^ the
projected  growth rates would be 0.06 U for Pond 1 and 0.48 U for
Pond 3.  Obviously such a difference did not occur.  They further
determined that the maximum growth rate (U) for hyacinths is 0.1145
g-wet weight/g-day.  This implies that in Pond 1 the growth should be
0.00687/day and Pond 3 should be 0.05496/day.  In reality, using the
best fit equations for Pond 1 and Pond 3, it can be determined that the
growth rates averaged 0.065/day for Pond 1 and 0.04_3/day for Pond 3.
    If total nitrogen, instead of just nitrate (N03) is used with the
Musil and Breen (1977) findings, then with Pond 1, at an average TN
concentration of 19.8 mg/l-TN and with Pond 3 at an average concentra-
tion of 10.5 mg/l-TN, the projected growth rates are 0.091/day for Pond
1 and 0.081/day for Pond 3 at 25°C.  Using the Van'tHoff rate for
adjustment to temperature, it is projected that at 15°C (59°F) the
maximum growth rate would be 0.057/day and the subsequent rates  in
each pond  would be 0.046/day for Pond 1 and 0.041/day for Pond  3.  This
is a fairly close projection for Pond 3 but somewhat low for Pond 1.
The projected trend, however, is comparable to actual field data.
    The work of Misil and Breen (1977) is most helpful in developing
and understanding the growth kinetics of hyacinths in the Lakeland
                               280

-------
situation.  Some caution must be taken, however, when trying to express
growth rate kinetics in terms of one nutrient.
    There was noticeable change in water quality as the percent in
hyacinth coverage changed as is shown in Table 1, and Figures 5 and 6.
The most relevant observations were as follows:
        Oxygen levels were maintained at adequate levels, even below
the hyacinth mats.  In Pond 1, where the lowest levels would be
expected, the DO rarely fell below 2.0 mg/1 anywhere in the system.
Oxygen levels were often above saturation in Pond 3 because of the
dominance of phytoplankton.
        Changes in pH were from neutral or near neutral to slightly
alkaline.  Again, this was due to algae production in Pond 3.
        BOD  and SS were reduced somewhat, particularly later in the
program.  Constant algae blooms in Pond 3, however, keep these levels
higher than what will be expected when coverage is complete.
        Nitrogen and phosphorus uptake exceeded that expected for the
measured crop density of 99 metric tons/ha (44 wet tons/acre) as is
shown in Figures 5 and 6.  This additional uptake apparently is
related to uptake within other compartments of the ecosystem.
        Water color and turbidity were reduced noticeably throughout
the system except during extremely active algae blooms.
        Dissolved solids were noted to decrease somewhat despite the
high evapotranspiration.  This is probably due to selective uptake
of certain ions such as ferrous ion, calcium, and chlorides.
        Coliform reduction was quite dramatic.  This correlates well
with the literature.
        Nitrogen transormation appeared at first to be towards
nitrification.  As coverage increased, however, nitrate was noted to
decrease throughout the system.  The exact nature of nitrogen trans-
formation throughout the ponds is undoubtedly quite complex.  The
fact is, however, that whether the hyacinths are directly using organic
and ammonia nitrogen, or whether they are using only nitrate which  is
being supplied by nitrifying bacteria, a limiting growth factor related
to the nitrogen species present is not demonstrated by this study.  If
hyacinths are in fact dependent upon nitrate, as suggested by Musil
and Breen (1977), then they are quite effective in supporting an active
nitrifying population within their root systems.
    Perhaps the most dramatic change noted throughout the system was
the change in biological composition and diversity.  Pond 1 was
characterized by large hyacinths with a root to total plant length
ratio of about 1:3 to 1:4.  The roots often supported an extensively
developed bacterial slime.  In areas exposed to light, epiphytic
algae was also noted.  Macroinvertebrates were restricted to chironomid
larvae, larvae of the mosquito Culex quincifaciatus and a small unidenti-
fied snail.  Populations of two fish species, Gambusia affinis and
Poecilia latipinna were noted to be surviving quite well.  At one point
the fish population appeared to approach about  11 fish per square meter.
Young fish were noted in late February, indicating successful breeding.
    Mosquito larvae population at its peak approached about 2.6 million/
cubic meters or an estimated 2642 grams wet or  264 grams dry weight per
cubic meter.  Assuming that these larvae are about 1.5 percent phos-
phorus on a dry weight basis, it can be estimated that about 15 kg  (33
pounds) of phosphorus are tied up in their biomass.  If 5 percent hatch
                                      281

-------
                                                                                TABLE 1
                                                        BIWEEKLY WATER QUALITY DATA SHEET (COMPOSITE SAMPLES)

                                                                WATER HYACINTH DEMONSTRATION PROJECT
ro
oo
S3
Date
12/15
12/29
1/22.
1/25
2/12
2/14
2/19,
2/21.
2/26,
2/28
3/5

Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Flow
cfs mgd
0.190
-
0.190
-
0.190

0.190

0.085

0.084
0.065
0.086
0.049
0.084

0.086



0.072

Water
T








61
60
60
68
66
68
72
70
62
58


68
66
Air
T
AVG

66

67

52
-
65

55

57

57

66

53



70

pH*








7.23
7.67
7.38
8.67
7.40
9.10
7.22
9.42
7.40
8.95


7.15
9.0
DO*
mg/l
2.9
6.7
3.2
8.0
4.0
7.5
4.5
8.5
2.2
8.2
3.4
15.0
5.8
11.0
3.9
14.8
4.4
9.6
8.0
18.6
2.9
6.7
NO-3-N
mg/l
0.56
0.30
0.37
0.41
0.34
1.70
0.24
1.52
0.1
6.0
0.3
5.0
0.4
3.6
0.45
2.9
0.06
2.5
0.2
2.0
0.36
0.2
TKN
mg/l
19.06
21.6
19.20
14.30
20.14
12.24
23.20
12.80
20.7
7.4
22.1
7.1
24.0
6.8
19.5
5.5
21.4
5.5
20.3
5.8
16.5
4.5
TN
mg/l
19.62
21.90
19.57
14.71
20.48
13.94
23.44
14.32
20.8
13.4
12.4
12.1
24.4
10.4
20.0
8.4
21.46
8.0
20.5
7.8
16.9
4.7
Ortho P
mg/l


4.72
4.99




6.1
5.3
6.0
5.0
5.5
2.5
4.8
2.0
5.5
2.0
5.5


1.8
TP
mg/l
6.94
7.39
6.67
5.61
6.59
6.14
6.93
6.93
7.7
6.5
6.9
4.9
12.5
9.0
6.0
2.6
5.5
2.5
8.0
0.5
4.5
2.2
BOD,*
mg/l
-







24
15
13
10
50
36
18
11
20
18
24
18
12
7
SS
mg/l



-




12
7
5
2
17
30
39
39
5
28
14
28
10
20
TS
mg/l








411
403
409
395
411 "
376
423
423
394
386
-.
.
379
374
Fecal*
Coliforms
No./lOO
ml








TNTC
840
TNTC
870
TNTC
500
TNTC
130
TNTC
780

-
TNTC
700
Remarks and
Observations
% coverage • 0%

% coverage - 1%

% coverage - 3%

% coverage - 4%

% coverage - 12%

% coverage - 1 2%

% coverage - 16%

% coverage - 16%

% coverage - 23%

% coverage - 23%

% coverage - 32%

                                                              * Grab samples instead of composite at influent and effluent stations.

-------
                                                                                  TABLE 1

                                                                                 (Continued)

                                                         BIWEEKLY WATER QUALITY DATA SHEET (COMPOSITE SAMPLES)

                                                                 WATER HYACINTH DEMONSTRATION PROJECT
to
00
CO
Date
3/7
3/14
3/21
3/27
6/20
6/27
7/12
7/19
7/26
8/9

8/23

Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Flow
cfs mgd
0.071

0.065

0.064



0.258

0.240

0.154

0.120

0.177

0.225

0.235

Water
T
AVG

68
67
68
72
75
73
70
67
84
82
82
81
84
83
85
83
87
87
85
84
84
83
Air
T
58

68

68

59

83
83
79
79
83
83
85
85
87
87
83
83
83
83
ph*
7.12
9.13
7.0
7.95
7.05
8.80
6.85
7.53
7.10
6.80
7.10
6.65
7.09
6.54
7.10
6.80
7.00
6.90
6.76
6.62
6.63
6.90
DO*
mg/l
3.5
1.2
3.6
5.4
6.2
4.2
3.2
4.1
4.2
1.6
4.2
1.6
2.2
1.0
6.4
3.2
3.4
5.1
1.6
2.6
0.70
4.8
NO-3-N
mg/l
0.36
0.42
0.71
0.01
0.54
0.20
0.64
0.006
0.2
0.1
0.3
0.0
0.13
0.06
0.20
0.012
0.17
0
0
0
0.0
0
TKN
mg/l
17.3
4.2
12.9
4.3
15.1
5.7
18.6
3.7
11.8
2.0
8.5
1.6
6.6
0.9
13.4
1.1
13.7
0.8
13.4
1.4
27.2
4.2
TN
mg/l
17.7
4.6
13.6
4.3
15.6
5.9
19.2
3.7
12.0
2.1
8.8
1.6
6.7
1.0
13.6
1.1
13.9
0.8
13.4
1.4
27.3
4.2
Ortho P
mg/l
4.5
2.0


4.0
0.8
4.25
5.5














TP
mg/l
4.5
2.7
2.5
0.7
5.0
1.2
5.0
7.0
4.3
5.6
4.8
3.5
3.3
0.6
3.0
1.8
3.8
2.3
5.0
3.1
5.0
3.8
BODn*
mg/l
18
14
15
17
24
21


19
10
8
4
20
3
24
1
28
1
32
3
24
7
SS
mg/l
22
20
15
16
45
18
92
8
13
1
4
0
8
1
13
10
23
0
36
7
14
12
TS
mg/l
380
342
326
321
420
376
447
378
366
339
345
321
294
323
355
294
357
263
377
258
328
231
Fecal*
Coliforms
No./lOO
ml
TNTC
680
TNTC
650


















Remarks and
Observations
% coverage - 38%

% coverage - 42%

% coverage - 45%

Spraying for
Mosquito Larvae














                                                             'Grab samples instead of composite at influent and effluent stations.

-------
CO
                     100-
                      90-
                      80-
                      70-
            60-

PERCENT
COVERAGE 50-
                      40-
                      30-
                      20-
                      10-
                                          PROJECTED REMOVALS AT
                                          PRESENT DENSITY OF 99 METRIC "X
                                          TONS/ha (44 TONS/ACRE)        "* •
                                                                                         DESIRED
                                                                                         REMOVAL LEVEL (92%)
                                                                                                   OVSERVED REMOVALS
                                                                                                   y= 0.699X-17.11
                                                                                                   r = 0.87
                                                                                                   n-12
                                                              PROJECTED
                                                              REMOVALS AT
                                                              DENSITY OF
                                                              224 METRIC TONS/ha i
                                                              (100 TONS/ACRE)
                                                                              Figure 5:  Observed and Projected Trends
                                                                              I          on Nitrogen Removal Within the
                                                                              I          Lakeland Hyacinth System
10    20     30    40
                                                          50
                                                       60
90     TOO
                                            PERCENT REMOVAL (NITROGEN)

-------
           PERCENT
           COVERAGE
10
00
CJ1
                        100-
                         90-
                         80-
                         70-
                         60-
                         50-
                         40-
                         30-
                         20-
                         10-
     PROJECTED
     REMOVALS OF
   — EXISTING
     DENSITY OF
    99 METRIC TONS/ha
     (44 TONS/ACRE)
PROJECTED REMOVALS
AT DENSITY OF
224 METRIC TONS/ha
(100 TONS/ACRE)
                                                                                          DESIRED REMOVAL
                                                                                          LEVEL (92%)
                        V
OBSERVED REMOVAL
y = 0.425 X + 13
r = 0.83
n= 12
                   (Figure 6: Observed and Projected Trends
                   I         in Phosphorus Removal Within the
                            Lakeland Hyacinth System
                                  10     20     30     40    50     60    70     80
                                            PERCENT REMOVAL (PHOSPHORUS)
                90    160

-------
each day,  it can be determined  that about  .75  kg  (1.65  pounds)  of
phosphorus  is removed daily by  mosquitoes  alone.   This  accounts for a
33 percent  removal of the daily load.  Looking at  Figure  6  it now
becomes evident why the observed nutrient  removals can  be greater  than
the projected removal from productivity alone.  Unfortunately,  mosquito
larvae are  not a desirable larval form.  Other insects, however, might
well provide some assistance  in nutrient control within the ponds.
    The impact of the food web  upon nutrient removal, particularly
phosphorus, was demonstrated  following an  intensive spraying of diesel
fuel for mosquito control.  Upon dying, the larvae apparently released
their phosphorus into the pond  systems, causing the effluent concentra-
tion to increase from 0.7 mg/1  to over 6.0 mg/1.   It is important  then
to adopt a  mosquito control program that does  minimal harm  to other
invertebrates and plants and  assures that  a large mosquito larvae
population  does not develop.
    In Pond 2 the ecosystem appeared to be much more diverse.   The fish
population  grew extremely fast, as the fish appeared to favor this
particular  lagoon.  The invertebrate population consisted of a  dragonfly
larvae, amphipods, damselfly  larvae, various water beetles and  their
larvae, several types of freshwater mollusks,  cray fish,  snapping
shrimp, and oligochaete and annelid worms.  In addition to Gambusia and
Poecilia populations, several Fundulus species (topwater minnows) were
noted as well as a killifish  species.  Tadpole populations were also
noted to be developing.  Tadpoles, which are a vertebrate larval form,
may also serve in nutrient control, much in the same manner as  mosquito
larvae.
    The hyacinths in Pond 2 suffered slightly  from chlorosis (a noted
iron deficiency).  The root to  total plant length was about 1:2 to
1:3.   The roots were clean as compared to Pond 1, and often supported
many invertebrate species.  The larvae of  the  Culux mosquito were
noticeably  scarce, often showing population of less than  270 per square
meter.
    Pond 3  showed an even greater diversity of invertebrate and fish
life.   Mosquito larvae were virtually absent except in  small isolated
areas.  The hyacinths were very chlorotic prior to iron treatment, with
a root total plant ratio of 1:1.5 to 1:2.
    A detailed population and species diversity study was not made
during this first phase of the  project.  Once  a stable ecosystem has
been established, however, an attempt will be made to identify  the
more critical species involved  in the nutrient dynamics.
    Based upon the water quality and flow data and the productivity
rates, a nutrient and water budget for the ponds was projected.  This
information is graphically illustrated in Figures 7 and 8.  Shown in
Figure 7 is a projection of the fate of nutrients and water during the
104 days of Phase 1.   Presented in Figure 8 is a projection of  nutrient
flows  for a stable system based upon the data  collected during  Phase 1.
Figure B is based upon weekly harvesting with  an average growth rate
coefficient of 0.33 and the assumption that at 1.5 mg/1 total nitrogen,
the growth  rate will have decreased by 75 percent.  The interesting
point  here  is that nitrogen may have to be added to the system, perhaps
as much as  is contributed initially by the wastewater.  This may
accommodate complete phosphorus control.   The need and cost for  this
"fertilizer" nitrogen will be determined during Phase 2.
                               286

-------
00
INPUT


NITROGEN  (2330 LB.)  1059 Kg.

PHOSPHORUS (753 LB.) 342 Kg.

WATER
 EFFLUENT =(13.4 MG) 50,719 CUBIC METERS

 RAIN-(1.2 MG) 4600 CUBIC METERS

 TOTAL «= (14.6 MG)  55,319 CUBIC METERS —
                                                                 H2O (3.5 MG) 13,248 CUBIC METERS


                                                                               EVAPOTRANSPI RATION
                                                                       POND SYSTEM
                                                                                                Figure 7:
                                                                                                    LARVAL RELEASE
                                                                                                    P- (104 LB.) 47 Kg.
                                                                                                    N - (520 LB.) 236 Kg.


                                                                                                    DENITRIFICATION (63 LB.) -N 29 Kg- N
                                                                                                                 H2O = (11.1 MG) 42,014 CUBIC METERS


                                                                                                                 N= (1,187 LB.)539Kg.


                                                                                                              «•  P = (485 LB.) 220 Kg.
                                                                                               Nutrient and Water Budget
                                                                                               Projected During 104 Days of
                                                                                               Phase I of the Hyacinth
                                                                                               Demonstration Project

-------
10
CO
CO
                                                                  (4.2 MG)  15,897 CUBIC METERS
                                                                           t.
            INPUTS


            NITROGEN (2330 LB.) 1059 Kg	

            PHOSPHORUS (753 LB.)  342 Kg	

            WATER

               EFFLUENT- (13.4 MG) 50,719 CUBIC MET£RS

               RAIN = (1.2 MG) 4600 CUBIC METERS

               TOTAL = (14.6 MG) 55,319 CUBIC METERS
            FERTILIZER

            NITROGEN (2,920 LB.)  1325 Kg.
                                                                                       SEDIMENTS
                                                                                     IN EQUILIBRIUM
ESTABLISHED
   ANIMAL
POPULATION
                                                                                                    DENITRIFICATION (63 LB.) - N 29 Kg. -N
                                    HARVEST  NITROGEN = (4647 LB.I 2108 Kg.
                                              PHOSPHORUS = (697 LB.I  316 Kg.
                                              WATER = (0.26 MG)  984 CUBIC METERS

                                    LARVAL
                                    RELEASE  NITROGEN = (250 LB.) ii3Kg.
                                              PHOSPHORUS = (34 LB.)  15 Kg.

                                           OUTPUTS
                                           NITROGEN = (127 LB.)  58 Kg

                                           PHOSPHORUS = (34 LB.)  15 Kg

                                           WATER = (10.14 MG)  38,380 CUBIC METERS
                                                                                                  (ASSUMPTION THAT HARVESTING IS DONE WEEKLY)
                                                                     POND SYSTEM
                                                                                              Figure 8:      Projected Nutrient and Water
                                                                                                            Budget During Typical 104 Days
                                                                                                            During Stabilized Conditions
                                                                                                            of Hyacinth Treatment System

-------
HARVESTING, PROCESSING AND DRYING

    Most of the work dealing with harvesting, processing and drying was
modeled after the work by Bagnall (1976).  Using a 30.4 cm (12-inch)
screw press designed by Dr. Bagnall, it was found that from 1.8-3.6
metric tons (2-4 tons) of wet hyacinths could be processed per hour.
The press was driven by a 50 HP tractor with power take-off.  If a
properly designed feed system were used, it would be quite possible for
the press to require only one operator.  Estimated energy consumption
for pressing whole hyacinths is approximately 6.2 kwh/ton or a cost
of approximately 28
-------
 capability to consistently reduce the moisture content to about 20
 percent in five days.   The present dryers cost approximately $10.78/
 sq.  meter ($l/sq.  ft.).   If they were to be built in such a way that
 they were logistically efficient and physically strong enough to last
 at  least five years,  however,  it is estimated that the cost would be
 about $32.28/sq. meter ($3/sq.  ft.)-   This would elevate the capital
 cost estimate for  drying to about $66,050/million liters-day ($250,OOO/
 mgd),  not including  land purchase.   Properly designed,  however, the
 solar dryer system will  have virtually no energy demand, and labor
 costs should be no more  than two persons per 4,650 sq.  meters (50,000
 square feet)  of dryer.   This amounts  to approximately 93c/wet metric
 ton  (85c/wet ton)  of  harvested  hyacinths for drying.   It is felt
 that certain design  features could  be added to the dryers to decrease
 the  drying time, and  subsequently reduce the overall  labor costs.   The
 most notable of these  improvements  would be to make it  possible to
 easily turn and spread the  material on the dryer  on a daily basis.
 Another  idea  is to augment  the  drying process  with a  continuous,
 heated air  type dryer.   This would  relieve the demands  upon the direct
 insolation  dryers  from 15-20 percent  to  40-55  percent moisture.  The
 continuous  flow dryer would be  an integral part of a  feed pelletizing
 system.
MARKETING POTENTIAL

    While there may be several marketing pathways for water hyacinths,
the Lakeland study has placed more emphasis on their feed potential.
It is felt that a feed produced from water hyacinth? ,fiber concen-
trate, and taste and vitamin additives will make up the major portion
of a complete dairy or beef feed rationing.  Working with a local  feed
producer, hyacinths at 20 percent moisture have already successfully
been included as a pelletized feed on a small scale.  These hyacinths,
which contain around 20 percent crude protein on a dry weight basis ,
theoretically represent an inexpensive 3 high quality source of
digestible nutrients and minerals when fed at about 20 percent of  the
total ration.  Their estimated value, at 20 percent moisture is about
$22-$33/metric ton ($20-$30/ton).  This amounts to an estimated cost
recovery of about $30,383/million liters-day ($115,000/mgd).
    As of yet, this feed has not been fed to actual test animals.  More
detailed work will be needed to check levels of toxic materials which
may interfere with the concept's viability.  Preliminary laboratory
tests, however, indicate that the material is suitable.  Presently, the
City of Lakeland is awaiting reply on a request for EPA funding to
further investigate this feed option.
    The market potential in Florida alone for dairy cattle is about
4,085 metric tons/day (4,500 tons/day) of feed.  The hyacinth demand
would be twenty percent of this, or 817 metric tons/day (900 tons/day)
(at 20 percent moisture).  This correlates to what would be produced
daily by about 0.22 million cubic meters/day (58 mgd) of domestic
wastewater.  There is evidence, therefore, that water hyacinth treat-
ment would have to be utilized by approximately 20 percent of all
wastewater systems within Florida before the State's dairy market
would become saturated.   Considering the possibility of an expanded
                              290

-------
national and international market, and the possibility of use with
other livestock, it can be deduced that there is a rather expansive
potential market.
PROBLEM AREAS

Frost

    During the winter months the temperature fell below freezing twice.
During the most intensive exposure, temperatures were at -3°C (27°F)
for three hours.  This resulted in some damage to the outer leaves,
but did not destroy the plants, nor did it noticeably retard their
productivity.  According to Penfound and Earle (1948), the hyacinth
will not be injured to a point where recovery will not occur until the
temperatures fall below -5°C (23 F) for 12 continuous hours, or below
-3°C (27 F) for 48 continuous hours.  Such occurrences are extremely
rare in Florida.  To counter the impacts of such rare instances, a
spray system could be utilized to protect 30 percent of the crop.
The remaining 70 percent could be harvested.  Replacement of this
standing crop would occur in approximately 15 days 3 during which time
the nutrient allocation may be exceeded.  This, however, would be a
brief violation, which would not result in an actual violation based
upon annual or monthly allowances.  The assessment at this point is
that the winters in Lakeland will pose no major threat to the
systems viability, nor will any measures taken to prevent frost
damage be cost prohibitive.  The actual projected costs for frost
prevention will be presented in the final project evaluation.

Mosquitoes

    The major problem encountered during the early phase of the project
was the development of huge populations of the mosquito Culex
quinci fac iatus.  Once a large fish population was established, however,
and the system stabilized, the mosquito population virtually was
eliminated.  As of yet, they have not reappeared.  Control measures
considered along with fish populations are parasitic nematodes
(Peterson; 1975) and monomolecular alcohols  (Levy; 1979).  From review
of other hyacinth projects, it appears that biological control is
adequate for elimination of significant mosquito populations.

Phosphorus Removal

    During the summer months, once the ponds filled with hyacinths, it
was found that an effluent could be consistently produced at concentra-
tion of 2.0 mg/l-TN, 4 mg/l-BOD, and 4 mg/l-SS.  Phosphorus levels,
however, have fluctuated between 0.2 mg/1 and 4 mg/1.  As noted, the
nutrient ratios in the wastewater  are not conducive  to phosphorus
removal.  Furthermore, it  is felt  that sloughing of  tissue from older
plants may be contributing to  this problem.  Regardless, it appears
that additional management practices or perhaps additional treatment
regimes may be required to control phosphorus.  One  concept  is  to
apread the recovered effluent on a rapid  infiltration system prior  to
                                      291

-------
final disposal.  More consistent and selective harvesting, more inten-
sive ecological management, and increased detention times may also be
utilized for enhancement of phosphorus removal capabilities.  Consider-
able work is needed in evaluating the phosphorus removal mechanisms
within these hyacinth systems.

Politics and Funding

    Since its first consideration as a feasible treatment method to be
included in 201 planning in Lakeland, the use of water hyacinths have
met almost constant opposition from state and federal environmental
agencies.  The basic reasoning has been that it was not a proven
technology.   The fact is that almost all advanced waste treatment
methods are not really proven, technologies.  This has been the major
force which instigated the innovative and alternative technology
support written into PL95-217.  Fortunately, water hyacinths are now
included as an innovative land application method, although the quoted
nutrient removal reliabilities may be somewhat conservative.  No
201 in the country at this time, however, is receiving Federal dollars
for design and construction of a water hyacinth system.
    As noted, this demonstration project was totally funded by local
dollars — despite a formal request to EPA for $80,000 R&D funds.  The
rejection of these funds came shortly after a nearby private group
received almost ten times that amount to construct and implement a
hyacinth project.  This gesture was understandably interpreted as an
inequity.  As might be expected, it encouraged a feeling of distrust
towards the Federal government.  This continual refusal of participa-
tion by EPA has created a generally cautious attitude in some of the
local officials.  Dealing with some of these political problems, which,
in all truthfulness, have been largely created by EPA's reluctance to
properly interpret and implement the directives of PL95-217, will
undoubtedly be the major obstacle confronting completion of this
project and the Lakeland 201.
                               292

-------
                             REFERENCES

1.   Bagnall, L.  0.  (1976).   Intermediate-Technology Screw Presses for
    Dewatering Aquatic Plants, Institute of Food and Agricultural
    Sciences.  University of Florida, Gainesville.

2.   Bagnall, L.  0.  (1979).   Associate Professor Agricultural Engineer-
    ing, University of Florida, Gainesville, Personal Communications.

3.   Levy, R. (1979).   Research Entomologist.  Lee County Mosquito
    Control District, Fort Myers, Florida, Personal Communication.

4.   Musil, C. F. and C. M.  Breen (1977).  The Application of Growth
    Kinetics to the Control of Eichhornia Crassipes (Mort) Solms.
    through nutrient removal by mechanical harvesting,  Hydrobiologia
    53,2/165-171.

5.   Penfound, W. T. and I.  T. Earle (1948).  The Biology of the Water
    Hyacinth,  jlcol.  Mono 18:447-478.

6.   Peterson, J. J.  (1975).  Penetration and Development of the
    Mermithid Nematode Reesimetis Nielseni in Eighteen Species of
    Mosquitos.  Journal of Nematology 7:3;297-210.

7.   Sculthrope, C.  0.  (1967).  The Biology of Aquatic Vascular Plants.
    London: Arnold.

8.   Wolverton, B.  C.  and P. C. McDonald (1978).  Upgrading Facultative
    Waste Stabilization Ponds with Bascular Aquatic Plants.  NASA NSTL
    Station, Mississippi.  ERL Report 172.
                                      293

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Other Aquatic Processes
Session

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   Photo of the recently completed Solar AquaCell system built
at Hercules, California. Comminuted wastewater passes through
the two stage anaerobic AquaCells on the right side of the
picture, designed to provide 12-20 days detention. The waste
water then passes through an aerated facultative AquaCell to
maximize oxygen transfer and additional AquaCells covered
with water hyacinths and duckweeds. The insert depicts plastic
BIOWEB structures that provide increased surface area for
microbial growth in the anaerobic and aerated AquaCell units.

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               OTHER AQUATIC PROCESSES:  SESSION SUMMARY


     The session on "Other Aquatic Systems for Wastewater Treatment,"  as  the
title implies, included diverse papers.   It is revealing to consider the  reasons
for the many different approaches to wastewater treatment that have been  repre-
sented at this seminar.  If there is one thing common to all of these  practices,
it is that each has a unique set of man-made and natural ecological constraints.

     Among the man-made constraints are: (1) the volume and make-up of the waste
to be treated, characteristics of which vary from community to community,
seasonally and diurnally, and with the degree of pretreatment provided;  (2) the
standards for wastewater effluent discharge that must be met by the treatment
system; and, (3) the economic basis and the resources available for the project.

     Ecological laws, of course, form the basis for our efforts to utilize
natural aquatic processes to treat and recycle waste, and lead to much of the
diversity seen in aquaculture treatment systems.  Although many aquatic plants
are cosmopolitan, some will perform better than others under particular climatic
conditions.  Similarly, the choice of organisms for use in wastewater treatment
will vary with the type of waste to be treated; an organism's tolerances  of the
chemical and physical extremes of the wastewater environment will in part deter-
mine its suitability for use in a given aquaculture treatment system.   Finally,
impounded wastewater forms no less complex an ecosystem than natural surface
waters.  Many of the same natural processes that produce fluctuations in  dissolved
oxygen and carbon dioxide content, light intensity, reproduction rates,  and
a host of other chemical, physical and biological parameters in natural waters,
also operate in wastewater treatment projects involving aquaculture systems.

     The possible combinations of these man-made and natural variables alone
guarantee that a wide range of conditions will occur in aquaculture treatment
systems.  To this point, the speaker's responses have been almost as varied and
can be best summarized by the following quote from the speaker Uarrell L. King:

     "A great variety of biological, chemical, and physical factors interact and
     feedback to set limits on the ability  of natural ecosystems to process
     wastewater.  An understanding of these ecological limits allows better
     design of alternative wastewater management systems which can be tailored
     to fit local environmental and wastewater conditions  relative  to local
     wastewater effluent standards."

Session Moderators:

     A. W. Knight, Professor
     Department of Land, Air and Water  Resources
     University of California
     Davis, California  95616

     Frank  T. Carlson
     Office of  Water Research  and  Technology
     Department  of  the Interior
     Washington, DC   20240
                                           297

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     SOME ECOLOGICAL LIMITS TO THE USE OF
     ALTERNATIVE SYSTEMS FOR WASTEWATER
     MANAGEMENT

     Darrell L. King, Institute of Water Research,  Michigan State
       University, East Lansing, Michigan 48824
     A great variety of biological, chemical, and physical factors
interact and feedback to set limits on the ability of natural ecosystems
to process wastewater.   An understanding of these ecological limits
allows better design of alternative wastewater management systems which
can be tailored to fit local environmental and wastewater conditions
relative to local wastewater effluent standards.  Ecological interac-
tions responsible for oxygen supply for BOD satisfaction, plant pro-
duction, and nutrient removal and recycle by alternative wastewater
systems are considered for aquatic ecosystems and combinations of
aquatic and terrestrial ecosystems.
INTRODUCTION

     When considering the use of natural ecosystems as means of waste-
water treatment, it is tempting to picture a series of ponds, perhaps
coupled with a terrestrial irrigation system, which will satisfy many
different desires.  Often such conjecture includes a natural solar
powered wastewater recycling system which produces large amounts of food
stocks, serves as a recreational site, produces minimal sludge and
recharges groundwater or surface water with water from which all nitro-
gen, phosphorus, deleterious organics, metals, bacteria, and viruses
have been removed.  Zero surface discharge and optimal fish cultures are
other attributes often desired from such systems.  But, accumulating
information from various operating aquatic, terrestrial, and combination
aquatic-terrestrial wastewater recycle systems casts serious doubt on
the ability to meet these various goals with any one system with current
management practices.
     This suggests certain limits to the use of such systems, but it
does not indicate that these natural systems have no place in waste-
water treatment.  The standard of comparison should not be whether or
not these natural systems meet all of these Utopian goals, but rather
how they compare with modern mechanical systems in meeting wastewater
standards.  In the long term, the most meaningful comparison may well be
that of wastewater treatment efficiency per fossil fuel energy input.


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But, to  truly judge their effectiveness, such alternative systems must
be designed and operated to take full advantage of the various natural
processes within the constraints imposed by the complex physical, chemi-
cal, and biological interactions which characterize, control, and limit
natural ecosystem function.  Without careful attention to such ecologi-
cal limits, these alternative wastewater management systems may fail to
yield desired results in any of several different areas.
     The purpose of this paper is to consider some of the ecological
limits to various suggested uses of alternative wastewater management
systems which rely on natural ecological processes.
THE AQUATIC ECOSYSTEM

     The usual comparison between conventional mechanical wastewater
treatment systems and those which use natural ecological processes
stress the differences and minimize the similarities.  And yet, even the
modern activated sludge process relies on biological concentration of
organics by a portion of the aquatic ecosystem supported by mechanical
intervention.  Oxygen required for bacterial respiration is supplied by
mechanical means and excess respiratory biomass is mechanically removed
as sludge; but, even in this ecologically simple, largely controlled
system, shifts in species of biota at times cause an undesirable change
in performance.
     Ponds of some sort are an integral feature of most alternative
wastewater treatment systems where their use may range from BOD reduc-
tion to storage of wastewater prior to application to some type of
terrestrial system.  Regardless of the use of the pond, impoundment of
wastewater markedly increases the complexity of the aquatic system used
as a wastewater treatment process.  The decreased reliance on energy
demanding mechanical processes is accompanied by a loss of control of
the system.  The efficiency of wastewater renovation is then dependent
upon the limits imposed by the natural pond ecosystem.
     The first use of the pond ecosystem for wastewater treatment in
this country was the sewage lagoon.  Initiated in Texas and North Dakota
the use of lagoons expanded greatly after the study at Fayette, Missouri,
(1) indicated their significant removal of BOD5 and coliform bacteria.
     The most widely used lagoon is the faculative lagoon usually
operated from three to six feet deep with an anaerobic bottom covered by
an aerobic surface layer maintained by planktonic algae.  The aquatic
process responsible for wastewater renovation in lagoons is often viewed
(2)(3) as a symbiotic arrangement in which bacterial release of
nutrients from waste organics supports algal photosynthesis which in
turn supplies oxygen to the bacteria.  The aquatic ecosystem of the
lagoon is far more complex than this and relies heavily on the alka-
linity system for the carbon dioxide required for algal photosynthesis
(4).  In fact, the carbonate-bicarbonate alkalinity system serves as a
bank from which carbon dioxide can be withdrawn during the daylight
hours for sufficient photosynthetic oxygen production to meet the night
respiratory demands.  Night respiratory release of carbon dioxide
recharges the alkalinity system prior to the next sunrise if the lagoon
is in some degree of balance.  This process which allows capture of
respiratory carbon dioxide and allows diurnal variation of dissolved
                               300

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oxygen from near 1 mg C>2/£ to levels in excess of 30 mg 02/2, and diurnal
pH variation of up to 3 pH units is depicted in equations 1, 2, and 3 as
the sum of the first and second dissociations of carbonic acid.

              ~ + U+-£=Z C02 + HOH                                  (1)


               ^=^ C0= + H+                                       (2)
                  ^=? C02 + CO   + H+                               (3)

     The significantly greater departure of the dissolved oxygen concen-
tration of the lagoon from atmospheric saturation during daylight super-
saturation than during the undersaturation of the night yields a net
loss of photosynthetic oxygen to the air when light intensity and tem-
perature allow active algal photosynthesis.  This leads to a net extrac-
tion of carbon dioxide from the alkalinity, an increase in pH, and a
decrease in the free carbon dioxide concentration of the water as a
function of increased time of detention of the wastewater within the
lagoon (5*).  The resulting decreased carbon dioxide level causes changes
in algal species culminating in dominance by the blue-green algae (4).
The probability of establishment of blue-green algal dominance thus
increases as a function of increased detention time of the wastewater
within the lagoon.  The blue-green algae, buoyed up by their gas
vacuoles, do not readily sink in the lagoon and thus increase the algal
content of the effluent from the pond, thereby yielding elevated efflu-
ent suspended solids concentrations.
     Regardless of the algal type, production of oxygen by the lagoon
algae is accompanied by the production of considerable organic matter
in the form of algal protoplasm.  Use of photosynthetic oxygen to meet
the oxygen demand imposed by bacterial respiration of waste organics
leaves an oxygen demand in the water in the form of algal protoplasm
which must be satisfied at a future time.  Exportation of algal laden
lagoon effluent to receiving streams places the burden of meeting oxygen
demand imposed by the lagoon algae on the stream ecosystem (6)(7).
     The expansion of the use of lagoons was based largely on the
results of studies which showed lagoons to yield excellent removals of
both coliform bacteria and BOD5.  Subsequently, it was shown that for
algal laden lagoon effluents the conventional measurement of BODs
included only about 20 percent of the ultimate BOD (6)(7) because the
algae do not lyse and release their contents for bacterial attack in
the five day incubation period within the BOD bottle.  However, as long
as the standard applied was BODs, lagoons generally met standards.
Addition of a suspended solids standard forced consideration of the
algae in the effluent, not adequately measured by BODs, an<^ most lagoons
no longer met standards.  This called for an energy dependent mechanical
intervention for removal of algae and some of the apparent advantage of
the lagoon was lost.
NUTRIENT REMOVAL BY PONDS

     Continued upgrading of wastewater standards has in many areas
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Included imposition of nutrient limits on wastewater effluents, with the
nutrients most commonly considered for elimination being phosphorus and
nitrogen.  Harvest of aquatic vegetation and animal products, sorption
on the pond bottom and chemical precipitation under the high pH condi-
tions generated in such ponds are all viewed as good methods of nutrient
removal within wastewater ponds.
     The potential for natural aquatic systems to remove nutrients is
under study at the Water Quality Management Facility (WQMF) at Michigan
State University.  This facility, charged with 0.5 MGD of good quality
secondary effluent, allows evaluation of the potential of both aquatic
and terrestrial systems for the management of nutrient rich wastewater
(8).  Within the WQMF, the wastewater flows by gravity through a series
of four ponds to a pumphouse from which it is applied as spray irriga-
tion to a 130 ha site containing oldfields, forest, and crop land.  The
ponds range from 3.23 to 4.98 ha with a total pond surface area of 16 ha.
Maximum pond depth is 2.4 m at the outlet and mean operating depth is
1.8 m to place the entire pond bottom within the photic zone to encour-
age growth of aquatic macrophytes.  The secondary domestic effluent
conveyed to the WQMF contains 16-20 mg N/£ and about 5 mg P/& with a
BODs usually less than 10 mg/£.  The secondary effluent coming into the
pond can be routed directly to the pumphouse or water from any of the
four ponds can be routed to the pumphouse for spray irrigation on the
terrestrial site.
     In response to the nutrient enriched wastewater which enters the
WQMF ponds, aquatic photosynthesis occurs at a rapid rate markedly
accelerating the biogeochemical cycle of carbon, nitrogen, and phospho-
rus.  Carbon dioxide uptake from the alkalinity by the algae and
macrophytes within the ponds is accompanied by significant oxygen pro-
duction and pH values often well in excess of 10 during the spring,
summer, and fall months.
PHOSPHORUS REMOVAL

     The three mechanisms for phosphorus removal within the pond systems
are sorption on the pond bottom, precipitation as a variety of phos-
phates under high pH, and uptake by plants.  Sorption on the bottom
sediments is finite and after slightly over a year of operation, the
phosphorus content in the outlet of the fourth WQMF pond exceeded the
Michigan effluent standard of 1 mg P/£.  Phosphorus is precipitated
during periods of high pH, but these precipitates are dissolved during
low pH characteristic of respiratory periods.  Macrophyte harvest, even
if 100 percent efficient, would allow only about 10 percent removal of
annual phosphorus load (9).  In effect, then, there is no natural
mechanism at work in pond ecosystems which will allow sufficient phos-
phorus removal in ponds to meet the Michigan phosphorus discharge
standard at any reasonable loading rate.  For a short period immediately
after construction, ponds may show excellent phosphorus removal.  But,
this will cease once the pond bottom becomes saturated with phosphorus
at equilibrium with the wastewater phosphorus concentration.  Thus, it
appears that pond systems will remove phosphorus just long enough for
the designer and contractor to collect their fee and leave town.
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NITROGEN REMOVAL

     Incoming nitrate nitrogen Is rapidly taken up by both the algae and
macrophytes, but particularly by the algae in the WQMF.  The resulting
plant mass is in turn rapidly cycled through the remainder of the aqua-
tic community, particularly the bacteria, with the nitrogen being
released as the ammonium ion.  Under the high pH maintained within the
pond by continued photosynthetic extraction of carbon dioxide from the
alkalinity, the ammonium ion is rapidly dissociated to free ammonia gas
according to equation 4 for which the pK is about 9,3 at summer tempera-
tures.

                                                                    (4)
     The free ammonia thus generated is rapidly lost to the air.  During
occasional periods of respiration following collapse of an algal bloom,
the lowered pH and decreased oxygen concentration may allow some deni-
trification with the consequent release of nitrogen gas.  However, the
generally very low nitrate concentrations, high pH, and high oxygen
concentrations suggest that the overwhelming bulk of the nitrogen loss
from the WQMF occurs as direct ammonia loss to the atmosphere.  Harvest
of macrophytes yields some nitrogen removal but even with near maximal
harvest only 9 percent of the observed nitrogen loss was accounted for
in plants harvested from the WQMF ponds (9) .
     The extreme dynamic nature of the ponds and the associated loss of
nitrogen to the atmosphere as ammonia yields an efficient means of
removing nitrogen from wastewater.  During 1976, when 0.5 MGD of secon-
dary effluent was passed through the four pond system, total nitrogen
concentration decreased as function of detention time as shown in
equation 5.

          N  = N  e~'°3t                                            (5)
           t    o

          Where:  N  = total nitrogen concentration mg N/2. at time t

                  N  = initial total nitrogen concentration in mg N/£
                   t = time in days

     Fifteen to twenty mg/£ total nitrogen entering the WQMF ponds was
reduced to about 0.5 mg total nitrogen/liter with a detention time of
120 days, while inorganic nitrogen concentration was at times as low as
0.05 mg N/£ in the fourth pond after about a 120 day detention period.
MEETING EFFLUENT STANDARDS

     The rapid cycling of nitrogen to ammonia and the elevated pH, both
maintained in wastewater ponds by the abundance of phosphorus available
to support aquatic photosynthesis, yields an extremely efficient system
for the removal of nitrogen from wastewater.  However, phosphorus
removal by the pond ecosystem is not sufficient to allow effluent from
the ponds to meet the effluent phosphorus standards currently in force
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 in  the  state  of Michigan.  To meet this effluent phosphorus standard,
 the WQMF  pond effluent  is  spray irrigated on an adjacent terrestrial
 system.   This integral  step required for phosphorus removal allows some
 recycle of nutrients  to  terrestrial biomass.  To gain such recycle, the
 WQMF must be  operated as a combination aquatic and terrestrial system.
     In Michigan, during the period from April to October, the active
 growth  of terrestrial vegetation incorporates nutrients from the waste-
 water applied to the  land.  To allow nitrogen addition to the land to
 meet plant needs during this period, it is necessary to minimize deten-
 tion time in  the ponds where nitrogen in the wastewater is rapidly lost
 to  the  air.   This is  accomplished on the WQMF by irrigating a mixture
 of  secondary  effluent and  water from the first pond during the spring
 and summer months.  With the absence of terrestrial vegetative growth
 during  the remainder  of the year, nitrogen in the wastewater applied to
 the land  is not removed and infiltrates to the groundwater.  Water
 irrigated on  the land during the winter infiltrates well (10).  But, to
 protect the groundwater from nitrate nitrogen, the wastewater applied to
 the land  during the winter must have an extremely low nitrogen content.
 Nitrogen  is efficiently removed from the wastewater impounded in the
 ponds during  the spring and summer months.  By October the ponds are
 full of wastewater with a  sufficiently low nitrogen content to allow
wastewater irrigation during the fall and winter months without eleva-
 tion of groundwater nitrogen levels.
     The  ability of terrestrial vegetation to remove nitrogen from
wastewater during the spring and summer is dependent on the type of
 terrestrial vegetation.  Oldfield grasses are quite efficient, agricul-
 tural crops show variable efficiency,  depending on the crop type, and
 forests are not efficient at removing nitrogen before it infiltrates to
 the groundwater (11).  Overall, the combination of ponds and land which
 comprise  the WQMF can be operated in a fashion which meets the stringent
 effluent water standards of Michigan.   Nitrogen is lost to the air as
 ammonia and nitrogen  gas and phosphorus is either sorbed on the terres-
 trial soils or harvested as terrestrial biomass.   Operated in this
manner, the WQMF approaches zero wastewater discharge.
AQUACULTURE IN WASTEWATER PONDS

     The long history of pond culture of a variety of fish in the Orient
in ponds charged with wastewater suggests an intriguing potential for
converting water-borne wastes to foodstocks within the United States.
However, it should be recognized that the wastewater aquacultural
successes of the Orient are allowed because they do not have to meet
either the environmental standards on the effluent from their ponds or
the public health standards on the product, both of which must be met
within the United States.  Our wastewater effluent standards include BOD
and suspended solids removal and in some locations nutrient limitations
as well.  Before aquacultural products from such systems can be marketed
as foodstocks in this country, they must be shown to be free from patho-
genic bacteria and viruses as well as having an extremely low burden of
the great variety of toxic and carcinogenic materials characteristic of
wastewater from a highly technical society.
     Even if such public health considerations can be overcome, there is
great difficulty in operating a pond system to meet modern effluent
                              304

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standards while simultaneously maximizing aquacultural yield.   It is
obvious that any attempt at aquaculture in wastewater ponds must not
impair the ability of the pond ecosystem to renovate wastewater.
     The nutrient content of wastewater is not in balance with the needs
of pond biota.  Phosphorus availability far exceeds nitrogen availability
which in turn far exceeds carbon availability relative to plant needs.
Carbon dioxide can be gained from the air while nitrogen is lost as
ammonia or nitrogen gas to the air.  Phosphorus is removed only by plant
uptake or by some portion of the phosphorus sedimentary cycle.
     When wastewater is impounded, photosynthesis by phytoplankton algae,
attached periphytic algae, and submerged macrophytes extracts carbon
dioxide from the alkalinity system at a rate greater than it can be
resupplied from respiration and from the air, thereby raising the pH of
the water.  The amount of pH elevation is directly related to the deten-
tion time in that the longer the water is held the greater is the carbon
extraction from the alkalinity.  A continually lowered carbon dioxide
content associated with continued detention yields a change in algal
species culminating in the buoyant blue-green algae (12).
     Such rapid photosynthesis supplies the energy necessary for rapid
cycling of the various nitrogen forms to ammonia, which, at the existing
high pH, is lost to the atmosphere as a gas.  Thus, with increased deten-
tion time, the ammonia nitrogen concentration will be reduced to the
point where it is no longer toxic to fish.  However, at this point the
nitrogen concentration often is no longer sufficient for any algae
except those blue-green algae which can fix atmospheric nitrogen.  These
blue-green algae cannot be harvested readily and since they are readily
utilized only by bacteria, they represent an oxygen demand which will be
exerted in the pond.  Within the WQMF, bacterial use of such nitrogen
fixing blue-green algae has caused sufficient oxygen depletion to yield
both summer and winter fish kills.
     If sufficient zooplankton are present in the pond to control the
mass of green algae and diatoms, the carbon extraction from the alka-
linity may not proceed to the point where blue-green algae dominate.
The addition of zooplanktivorous fish to such systems can reduce the
zooplankton control of the algae to the point where sufficient algal
mass accumulates to force a carbon dioxide level low enough for blue-
green algal dominance (13).  Phytoplanktivorous fish, such as some of
the oriental carp, would be able to maintain a green algal dominance if
the fish stocking rate was matched with the wastewater detention time
and the algal growth rate in such a manner that the algal content of the
effluent did not exceed effluent suspended solids standards.  This is an
extremely difficult balance to maintain and it is illegal to import such
fish into most states.
     Attempts to raise and harvest submerged macrophytes can be thwarted
by adding fish which crop the zooplankton, thereby allowing rapid expan-
sion of algal populations to the point where they limit the light avail-
able to the macrophytes.  In this instance, macrophytes are replaced by
phytoplankton, often blue-green algae.
     Cage culture of fish in wastewater ponds is limited by the char-
acteristic high pH of the ponds.  The waste products of the fish in the
cage represent a point source of  ammonia which, at the high pH, rapidly
dissociates to ammonia gas which  is toxic to fish.  While such  ammonia
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production may not kill the fish, the growth rate of the fish is
retarded (14).
     The necessity of balancing this complex set of interacting variables
to produce a product of value without impairing wastewater treatment
efficiency, coupled with the improbability of marketing the product, does
not indicate a great potential for wastewater aquaculture of foodstocks
in the United States at this time.
REFERENCES

1.  Neel, J.K., J.H. McDermott, and C.A. Monday, Jr.   1961.   Experimental
    lagooning of raw sewage at Fayette, Missouri.  J_.  Water Pollut.
    Contr. Fed., Vol. 33, pp. 603-641.

2.  Cooper, R.C.,  W.J. Oswald, and J.C. Bronson.  1965.  Treatment of
    organic industrial wastes by lagooning.  Proc. 20th Industrial Waste
    Conf. , Eng. Ext. Series 118, Purdue Univ., Lafayette, Ind.,  pp.  351-
    364.

3.  Rich, L.G.  1963.  Unit Processes of Sanitary Engineering.   Wiley,
    190 p.

4.  King, D.L.  1972.  Carbon limitation of sewage lagoons.   In  G.E.
    Likens, Ed., Nutrients and Eutrophicatlon, Special Symposium, Am.
    Soc. Limnol. and Oceanogr., Vol.  1, pp. 98-110.

5.  King, D.L.  1976.  Changes in water chemistry induced by algae.   In
    E.F. Gloyne, J.F. Malina, Jr., and E.M. Davis, Eds., Ponds  as a
    Wastewater Treatment Alternative, Water Resources  Symposium 9, The
    Center for Research in Water Resources, Univ. Texas at Austin.

6.  Bain, R.C., P.L. McCarty, J.A. Robertson, and W.H. Pierce.   1970.
    Effects of an oxidation pond effluent on receiving water in  the San
    Joaquin river estuary.  2nd International Symposium for Waste Treat-
    ment Lagoons,  R.E. McKinney, Ed., Lawrence, Kansas, pp.  168-180.

7.  King, D.L., A.J. Tolmsoff, and M.J. Atherton.  1970.  Effect of
    lagoon effluent on a recieving stream.   2nd International Symposium
    for Waste Treatment Lagoons, R.E. McKinney, Ed.,  Lawrence, Kansas,
    pp. 159-167.

8.  King, D.L. and T.M. Burton.  1979.  A combination  of aquatic and
    terrestrial ecosystems for maximal reuse of domestic wastewater.
    Water Reuse Symposium, Water Reuse from Research to Application,
    AWWA Research  Foundation, Denver, Colorado, Proceedings,  Vol.  1,
    pp. 714-726.

9.  King, D.L.  1978.  The role of ponds in land treatment of wastewater.
    International Symposium, State of Knowledge in Land Treatment of
    Wastewater, U.S. Army Corps of Engineers, Cold Regions Research and
    Engineering Laboratory, Hanover,  New Hampshire,  Vol. 2,  pp.  191-198.
                               306

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10.  Leland, D.E. ,  D.C.  Wiggert, and T.M.  Burton.   1979.   Winter spray
     Irrigation of  secondary municipal effluent.   J^.  Water Pollut.
     Contr. Fed., Vol. 51, pp.  1850-1858.

11.  Burton, T.M.  1979.  Land application studies on the Water Quality
     Management Facility at Michigan State University.  2nd Annual Con-
     ference of Applied Research and Practice on Municipal and Industrial
     Wastes, Madison, Wisconsin, Sept. 18-21, 1979.

12.  King, D.L.  1970.  The role of carbon in eutrophication.  _J. Water
     Pollut. Contr. Fed., Vol.  42, pp. 2035-2051.

13.  Helfrich, L.A.  1976.  Effects of predation by fathead minnows,
     Pimphales promelas, on planktonic communities in small eutrophic
     ponds.  Unpub. Ph.D. Thesis, Michigan State University, 59 p.

14.  Duffield, D.J.  1979.  Case culture of channel catfish, Ictalurus
     punctatus  (Rafinesque), in a tertiary wastewater pond and a private
     pond in southern Michigan.  Unpub. M.S. Thesis,  Michigan State
     University, 45 p.
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UTILIZATION OF SILVER AND BIGHEAD CARP
FOR WATER QUALITY IMPROVEMENT

Scott Henderson, Arkansas Game and Fish  Commission,
  P.O. Box 178, Lonoke,  Arkansas  72086

                           ABSTRACT

     Filter feeding fishes, the silver and bighead carp, were
stocked in an existing lagoon treatment system in 1975-76 for
a preliminary evaluation of the effect of the fish on water
quality and the potential of this nutrient source for fish pro-
duction.  Positive results have led to an ongoing Environmental
Protection Agency funded study of the efficacy of finfish as a
treatment method in a full scale, six cell (24 acre) treatment
facility at Bentoii, Arkansas.

     Information concerning water quality improvement, fish
production, product utilization and some design considerations
are presented.  The promising results, design adaptability,
and pay back possibilities make this an attractive, innovative
alternative.

                         INTRODUCTION

     Fertilization of fish ponds  has long been recognized by
the fish culturist as a method of increasing px'oduction.  The
production of finfishes as a method of reducing fertility is a
relatively new  approach that has  been stimulated by the in-
creasing need for effective, low  cost treatment of wastewater
by small municipalities.  The initial emphasis on this and other
"alternative" strategies as opposed to conventional methods was
largely a result of more stringent effluent guidelines and the
high cost of construction and operation of conventional plants.
It seems, however, that the even  more recent realization of
the need to conserve energy sources and to recycle what has
previously been discarded as a troublesome waste product has pro-
vided the impetus for exploring new technologies.  Also, even
the remote possibility of producing a useful and/or valuable
product from wastewater treatment demands attention.

     The Arkansas Game and Fish Commission's interest in this
project evolved from the importation into the state of two
species of Chinese carps by a private fish farmer.  The silver
carp, Hypopthalmichthyes molitrix, and bighead carp, Aristichthycs
nobilis, were brought into Arkansas in 1973 with initial interest
resulting from  the fact that they were unknown, exotic species
and the possibility of these low  trophic level filter feeders
being a beneficial addition to  fish production ponds.  Conversa-
tions with Dr.  S. Y. Lin who did  pioneering work with the Chinese
                                   309

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carp species in Taiwan and a visit to the Quail Creek Sewage
Treatment Project in Oklahoma during 1973-74 led to the current
interest in wastewater aquaculture.

     The fact that many finfish species ranging from the lowly
esteemed common carp, Cyprinis carpio, to the prize sport fish
the muskellunge, Esox masquinongy, have been produced in waste-
water ponds attests to the variety of species amenable to pro-
duction in nutrient rich v/astewaters under specific conditions.
The fact that X pounds of fish are produced without supplemental
feeding obviously shows that in one fashion or another, energy
and nutrients are transformed into the very stable form of fish
flesh.  This is the reasoning behind one of the basic tenets of
fish culture and management i.e., that within certain limits the
natural productive capacity of a given body of water is increased
by increasing available nutrients.  The fish culturist may draw
on a rather large body of available literature resulting from
research and practical experience in determining the proper type
and amounts of fertilizer to add to the culture pond.

     If, on the other hand, the objective is to utilize available
nutrients, little is known about the effectiveness of finfish in
general or of any particular species.  Common sense dictates
that those fishes that have adapted to feeding at the lower
trophic levels would be most efficient at converting nutrients.
Therefore, those that are able to feed on the primary productiv-
ity, the herbivores, should be considered the most likely can-
didates'for achieving the objective of nutrient utilization.  A
group of fishes known as the Chinese carps, in particular the
silver carp, meets this criterion and  is  the key species in
this study.

                     Silver and Bighead Carp

     The silver and bighead carp are native to the Amur River
basin along the Sino-Soviet border.  Stocks of these fish have
been propagated by the Arkansas Game and Fish Commission since
1973 for use in this and other research projects.  Both are
filter feeding fishes that feed on free-floating or free-swimming
planktonic organisms throughout their life.  These fishes are
capable of reaching a size of 18-23 kg (40-50 Ibs.) in four to
five years.

     The silver carp exhibits certain characteristics that make
it more desirable for this type of program than native filter
feeding species.  The specially adapted gill rakers that have
evolved as the filter for this species are somewhat unique and
are very efficient at filtering extremely small particles from
the water that passes through them.  The gill rakers of the
silver carp are similar to a sponge-like plate and are capable
of removing particles as small as four microns in size.  The
diet of the silver carp is composed primarily of phytoplankton.
                              310

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The gill rakers of the bighead are filaments that widen at the
distal end and overlap to form a more or less solid filtering
surface.  The filter of the bighead is comparable to many native
filter feeders and is not as efficient at removing the smaller
particles as is the silver carp.  The majority of the bigheads
diet consists of zooplankton and the larger phytoplankton species.
Both the silver and the bighead are capable of rapid growth,  are
not particularly susceptible to common fish diseases, and are
capable of withstanding relatively low dissolved oxygen levels.
For these reasons mentioned above it is believed by the author
that the silver carp should be the central species in a finfish
treatment system.  The bighead has certain desirable attributes
but could be replaced by other native fishes»

                   Description of Project Site

     The wastewater treatment plant of the Benton Services Center
was chosen as the site for the study.  The primary reasons for
its selection were the multiple ponds available, the capability
of controlling the pattern of flow through the system, and state
ownership which provides greater cooperation and control in
operation of the plant.

     The Benton Services Center is under the direction of the
Arkansas Department of Human Services.  The center provides both
mental and alcohol rehabilitation programs, a nursing home facil-
ity, and serves as a work release center for the Arkansas Depart-
ment of Corrections.  While numbers vary, there are approximately
1,000 persons residing at the center full time.  Other than day-
time  and around-the-clock patient care personnel, the center
maintains its own water treatment plant, fire station, laundry
food services department and a rather large maintenance and
grounds staff.  There are also several residences for staff
members located on the grounds.  There are, in all, approximately
1,000 full time employees at the center with some contributing
to the wastewater load during working hours six days per week
and others around-the-clock.

     Other than the collective individual needs, the biggest
contributors of wastewater to the system are the laundry and
food services.  The laundry is in operation six days per week
supplying the needs of the entire Benton facility and food ser-
vices prepares three meals per day for all residents and at
least one for every employee.  The character of the raw waste-
water is fairly typical of that produced by small municipalities
with no major industrial users.

     The physical facilities of the wastewater treatment plant
include (1) a bar screen and grinder for reducing the size of
larger debris entering the system, (2) a clarifier,  (3) an
aerobic digester (this is a converted anaerobic system providing
                                   311

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mechanical aeration to the solids from the clarifier, majority
of the water enters the lagoons from the clarifier), and six
oxidation ponds with a total surface area of 10.2 ha (24 acres).
The average daily flow of wastewater into the system is 1,711m*/
day (0.45MGD), the average organic load is 444 kg (977 Ibs.) of
BODs per day, and 208.6 kg (459 Ibs.) of suspended solids per day.

                   Preliminary Study (1975-76)

Methods

     In 1975, a preliminary study using only the silver and big-
head carp was begun at the Benton site.  At the outset of the
study, the flow pattern through the ponds was arranged so there
would be two completely independent three pond series.  The total
influent load was passed through a division weir with one-half of
the total volume going into the initial pond in each of the series,
The ponds in each series were numbered in the order the water
passed through them i.e.,  Ponds 1A and IB received the sewage
influent and the water was discharged from 3A and 3B.  The ponds
designated the "A" series were stocked with fish and the "B"
series received no fish and was used as the control.  (See
Appendix IA)

     The "A" ponds were stocked with fish as follows;

          Pond 1A (1.76 ha) -   450 grass carp (5-7 cm each)
                              1,275 silver carp (10-13 cm each)
                                280 bighead carp (10-13 cm each)
          Pond 2A (1.55 ha) -   400 grass carp (5-7 cm each)
                              5,250 silver carp (5-7 cm each)
                                380 bighead carp (10-13 cm each)
          Pond 3A (1.56 ha) -20,000 silver carp (5-7 cm each)
                                400 bighead carp (10-13 cm each)

Water samples were taken twice weekly from each of the six ponds.
One sample was taken at sunrise and the other at midday.  One
liter grab samples were taken at the effluent from each pond.
Water quality characteristics measured for each sample were:

    Dissolved Oxygen        Carbon Dioxide   Suspended Solids
    Air/Water temperature   Color            Phosphate, Total
    Turbidity               Fecal Coliform   NII3 - N
    Conductivity            Plankton Count   NO2 - N
    pH                      BOD 5             NO3 - N

HACH pre-measured reagents and spectrophotometric methods were
used in making most determinations.   Many testing procedures did
not comply with accepted Standard Methods.

Results

     There being no other apparent differences in the two sets
of ponds,  it is assumed that any differences in effluent quality
can be attributed to the presence of the fish.

                              312

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     The most notable differences in effluent quality were  found
to be in BODs and the types of phytoplankton organisms present.
Both are felt to be interrelated.  For the annual average,  the
BOD5 of the effluent from the ponds without fish was 37.6%  higher
than the series containing the fish.  The phytoplankton popula-
tion in Pond 3A (fish present) was never dominated by blue-green
species and no plankton die-offs were observed or recorded.   In
Pond 3B (no fish present), dense blue-green blooms,  floating mats,
periodic die-offs and associated odors were frequent occurrences
throughout the warmer months.  The continued healthy green
phytoplankton population with continuous 02 production in Pond
3A with no die-offs causing additional oxygen demands is attri-
buted to the constant "grazing" of the fish which resulted  in
decreased BODs levels.  For the most part, the remaining param-
eters measured were lower for the ponds containing the fish as
compared to those without.  With the exception of an overall
reduction of NH3-N of 27% in the fish ponds, the differences were
small.  While the accuracy of the methods used are questionable,
it is believed that they lend themselves to direct comparison.
Graphic representation of parameters measured during this
preliminary study are presented in Appendix IB.

Fish Production;

     Based on preliminary water quality data, it was considered
very doubtful that fish could tolerate the low DO levels in Pond
1A and none survived longer than the fourth week after introduc-
tion.  DO levels in Pond 2A appeared marginal for the support
of fish life, however, it seemed the feeding activity of the
fishes themselves provided a stabilizing influence on the usually
wide diurnal fluctuations of oxygen concentration.  Oxygen  re-
lated fish kills occurred in winter and early spring in this
pond as a result of abrupt seasonal changes as is typical of
fertile surface waters.  In both cases, fish were restocked re-
placing those lost.  No problems occurred throughout the year
in Pond 3A as oxygen levels remained well within limits necessai*y
for propagation of these fish.

     The fish were harvested at the end of this study and weighed
for total production figures.  A total of 6,546 kg/ha (6,003.8  Ibs.
per acre) were produced during the period from August, 1975 to
December, 1976.  This encompassed one full growing season in
Arkansas.  Total weight gain can be attributed to utilization of
natural food produced within the ponds as no supplemental feeds
were added to the ponds at any time.

               Present Investigations  (1977-1980)

     The promising results of the preliminary study described
above have led to continuing efforts at further evaluating this
method of wastewater treatment.  A research grant from EPA pro-
vided funds for minor site alterations and upgrading water quality
                                  313

-------
monitoring techniques to acceptable Standard Methods for v/aste-
water.  An additional federal grant from the National Marine
Fisheries Service is supporting further investigations in the
possibility of fish production and product utilization.

Site Alterations and Present Pond Operation

     The Benton Services Center treatment plant is again being
used.  Minor alterations in the existing facility were made
prior to stocking the fish and instituting routine water quality
monitoring.  The existing six ponds were dewatered, sludge build-
up was removed and the ponds regraded to their original contour
with some minor changes to facilitate the harvest of the fish.
All ponds average 1.2-1.3 m in depth with the bottoms being
graded to the deepest point of approximately 2 m.  The flow
pattern was arranged so the wastewater flows through each of the
six ponds in series with the ponds numbered one-six in the order
they receive the wastewater.  All wastewater entering the plant
is lifted by pumping into Pond 1 where it travels by gravity
flow - drop in elevation of approximately 0.76 m (2.5 ft.) - to
the surface discharge from Pond 6.

     By utilizing the existing piping system, the water flows
into each of the ponds at the midpoint of one levee and out an
adjacent side.  To prevent short circuiting and provide maximum
retention time, baffles were constructed diagonally, three-
quarte'rs of the distance across each of the ponds.  (See Appendix
IIA)  The influent flow rate of 1,711 m3/day (0.45 MGD) allows
for a residence time for the water in the entire six pond system
of 72 days.  The individual ponds are approximately equal in
size (range from 1.55-1.8 ha) with a retention time of about 12
days per pond.  Four recording flow meters have been installed
across the six ponds.  One is placed in a six inch Parshall
Flume measuring influent, two are placed at the outfall of ponds
two and four and the last at the end of the system recording
effluent flow.

     All wastewater flows directly into Pond 1 and then serially
through the remaining ponds.  Ponds 1 and 2 serve as stabili-
zation and plankton culture ponds and were not stocked with
fish.  The remaining four ponds were stocked with fish as follows;
          Pond 3 (1.55 ha)

          Pond 4 (1.8 ha)

          Pond 5 (1.67 ha)

          Pond 6 (1.56 ha)
20,270 silver carp (41
 4,103 bighead carp (32
12,198 silver carp (41
 2,052 bighead carp (32
12,070 silver carp (41
 2,052 bighead carp (32
 8,100 silver carp (41
   600 bighead carp (32
   600 channel catfish
   100 buffalofish (1.6
    40 grass carp (0.5
g each)
   each)
g each)
 g each)
g each)
 g each)
g each)
 g each)
(300 g each)
 kg each)
kg each)
                              314

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                    Water Quality Monitoring

     For the present study, one liter grab samples are taken
once weekly (between 7-10 am) from the effluent of each of the
six ponds.  All sampling and testing is performed according to
APHA Standard Methods for the Examination of Water and Waste-
water, 14th Edition.  Samples are taken and preserved at the
site as prescribed and delivered to the lab facilities of the
Arkansas State Department of Pollution Control and Ecology in
Little Rock, Arkansas where all testing of water quality is
conducted.  Water quality parameters measured weekly from each
of the six ponds are:

          Air/Water Temperature     N03~N
          Dissolved Oxygen          Conductivity
          BOD5                      Suspended Solids
          Turbidity                 Total P
          NHs-N                     Fecal Coliform
          NO2-N                     Plankton Count & Enumeration

The wastewater entering the plant has an average BODs of 260 mg/1
with suspended solids concentration averaging 140 mg/1.

     The loading rate for the initial pond is 242.5 kg/ha/day
(244 Ibs./acre/day) of BODs and 113 kg/ha/day (114.7 Ibs./acre/
day) of suspended solids.  When this loading rate is applied to
the total available area within all six ponds it amounts to
43.5 kg/ha/day of BODs and 20.4 kg/ha/day of suspended solids.

     During the first eight months of operation, the system has
reduced BOD5 by 96.4% and suspended solids by 86%.

     The present monitoring program has been in effect for nine
months and is scheduled to continue for one full year.  Because
of the time factor involved, all water quality data presented
in this report is taken from the first eight months of the study -
December, 1978 through July, 1979.

     During this period, the effluent has been within criteria
established for secondary treatment and in many instances
approached levels for advanced secondary treatment.  A complete
listing of effluent quality by month is presented in Appendix IIB
and the overall effect on the water quality in each of the ponds
is listed in Appendix IIC.

Fish Production

     To monitor the growth rate of the fish within this system,
monthly samples have been taken throughout the growing season
and individual fish weighed, measured, and returned to the pond.
It has been difficult to obtain adequate samples of species
other than the silver and bighead carps due to relatively low
                                   315

-------
 stocking  densities  and  the  inefficiency of sampling techniques.
 Based on  sampling information  as  of August 1 and assuming a
 realistic survival  rate of  85% of  the  fish initially stocked,
 there is  an  estimated standing crop of fishes in excess of
 22,777 kg (50,000 Ibs0)  in  the four ponds containing fish.
 This amounts to  a total average production of 3,344 kg/ha
 (3,125 Ibs./acre) with  approximately three months remaining in
 Arkansas'  growing season.

 Product Utilization

     Among the many organisms  that have been proposed at one
 time or another  as  biological  filters  for use in wastewater
 lagoons,  finfish are one of the most easily controlled and
 harvested for use utilizing existing state-of-the-art methods.
 Present technology  exists for  processing fisheries products
 for an existing  market.  There is, however, a bureaucratic
 "catch 22" preventing any product  directly derived from waste-
 water being  sold for human consumption.  While public health
 concerns  should  not be  minimized,  a low cost source of high
 quality protein  should  not be  overlooked with such a flippant
 attitude.

     Realizing the  problems of consumer acceptance and legal
 constraints  associated with the utilization of fishery products
 from wastewater  lagoons, a testing program was established at
 the beginning of this project.  While  it is certainly beyond
 the scope  and budget of  this project to consider all possible
 contaminants, a  private  testing lab was contracted to determine
 le-els of  what was  considered  to be the most likely pesticides,
 heavy metals and pathogenic bacteria present in the system.
 Samples *>f fish  flesh (edible  portion) and water from the in-
 fluent i\  J *he ponds themselves is being used for the testing.
All proceau.  is follow accepted standard methods.  Quality
 control measures practiced by  the private lab have been approved
 by the Arkansas Department of  Pollution Control and Ecology.

     Prior to beginning  the project, baseline data was estab-
 lished by  testing influent wastewater  and samples of flesh from
hatchery reared fish to  be stocked in  the lagoons.  Subsequent
quarterly  sampling  has been done on influent wastewater and
both water and fish flesh from two of  the four ponds stocked.
The ponds  sampled are alternated each  quarter.  In all sampling,
those contaminants  considered  were:

Pesticide  Scan          Metal  Scan     Path.  Bacteria Screen
Aldrin                   Lead           Salmonella/shigella
Dieldrin                 Copper         Staphylococcus
Endrin                   Cadmium        Edwardsiclla
Mirex                    Mercury        Clostridium
DDT (and derivitives)     Arsenic
Toxaphene
Kepone
PCB
                             316

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     With the exception of the metals, copper and mercury,  and
staphylococcus bacteria, all samples have shown less than the
standard detection limits or have been negative.   In no instance
has any sample been above action guidelines established by FDA
or the Arkansas Department of Health.

Cost Effectiveness

     According to EPA report 600/2-76-293 entitled Economic
Assessment of Wastewater Aquaculture Treatment Systems by Upton
Henderson and Frank Wert, 1976, only when finfish aquaculture
was not capable of meeting water quality objectives was it
deemed not to be cost effective when compared to conventional
systems.  The report went further to state that aquaculture
wastewater alternatives appear to be economically attractive
regardless of the market for products if water quality goals are
met.

     Although there are several possibilities and likely many
useful fishery products yet to be developed, it appears that
the long and the short of the present market lies with the sale
of the product as a food item and by processing it into fish
meal for use as an animal feed supplement.  It should be under-
stood that in present day fresh water pond aquaculture the
greatest overhead costs are land, feed, fertilizer and water.
By utilizing this system of wastewater aquaculture, these costs
would be borne by the primary function of water treatment.  By
accepting this and other rather basic assumptions within the
framework of present markets, some rather cursory economic pro-
jections can be made.

     Silver and bighead carp from the preliminary study were
rendered into fish meal which assayed at a crude protein
content of minimum 55-57%.  This is compared to 62% crude
protein for Menhaden meal considered the best product now
available.  Oil and fat content were not considered.  There
was an estimated 18% return of meal from fresh fish by weight.
Current market prices for pure fish meal, F.O.B. Little Rock,
vary from $4-500 per ton in bulk quantities depending on
season and harvest source.  Based on a price of seven-nine cents
per kg (three-four cents per pound) for live fish and an annual
production rate of 6,546 kg/ha as seen in the preliminary study,
a gross return of $430-$575/ha/year  ($180-$240/acre/year) could
be realized by processing the fish in this way.

     If, on the other hand, the fish were marketed for direct
human consumption at a conservative in the round price of
55-65 cents per kg (25-30 cents/lb.) the gross annual return
would be $3,600~$4,525/ha ($1,500-$1,SOO/acrc).  Whatever the
market, any profit realized would certainly be welcomed by
small municipalities to offset treatment costs.
                                   317

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                           APPENDIX IA
     Flow pattern and method of operation of the lagoons
used during the preliminary study, 1975-76.
                                319

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                               Influenti
Division Weir
                                                            Effluent
Benton State Hospital Sewage Lagoons.   "A" series of ponds stocked
with fish.   "B" series of ponds not stocked with fish and used as
control.
                               321

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                           APPENDIX IB
     Comparison of average monthly water quality data of
effluent from the series of ponds with and without fish
during the preliminary study, 1975-76.
                                323

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                  SEPT  NOV  JAN   MAR   MAY   JUL



                      TOTAL  NUMBER OF PLANKTON ORGANISMS
               PER LITER.  Pond  3A 'represented by solid

               line,  Pond  3B by  broken  line.
                                                           w
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                 TOTAL SUSPENDED SOLIDS.  Pond 3A

          represented by solid line, Pond 3B by

          broken line.

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                     AMMONIA-NITROGEN.   Pond 3A repre-
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                                                             70
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                                                                                                i   I

                                                                                                  AUG
                                                                   TOTAL, PHOSPHATE.  Pond  3A represented
                                                            by solid line, Pond 3B by broken line.

-------
        550



        560
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                                                                 AUG    OCT   DEC   FEB   APR   JUN   AUG

                                                                    SEPT   NOV   JAN   MAR   MAY   JUL
                     CONDUCTIVITY.  Pond 3A represented by

              solid line, Pond 3B by broken line.
                                                                        BODr-   Pond 3A represented by solid

                                                                line,  Pond 3B  by broken line.

-------
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                          11.0 --
                           10.5  --
                           10.0  --
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                                      SEPT   NOV   JAN   MAR   MAY   JUL


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                                  line, Pond 3B by broken line.

-------
   900,000
   800,000
o  700,000
o
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o
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o  500,000
o
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1:  300,000
   200,000
   100,000
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                                   20,000
                                   15,000
                                    10,000
                                    5,000
                                                ..j.
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                                                ;'•' «-••-i;:
                                                ,,.    .,,,

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                                                                          50 --
                                                                              40 --
                                                                              30 --
                                                                          20  -
                                                                          10
                                                                                 ,> ;•('-.»• :,
                                                                                'A ..i j-•.»
                                                                                • ,'>v:s'*i-
                 Fecal Coliform.  Avex^age number of  fecal coliform bacteria  found in  each

                 pond during  study period.

-------
                          APPENDIX IIA
     Flow pattern and method of operations of the lagoons
used during present investigations.
                                331

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                   	— V  Effluent
333

-------
                          APPENDIX IIB
     Average monthly water quality data from samples taken
of final effluent (Pond 6).
                               335

-------
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             DEC     JAU
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                                          337

-------
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                                        338

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                                               339

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                                                               JluE    JULY
                                            341

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                        APPENDIX IIC
     Change in water quality as flow progresses through
each pond in the series.  Values listed represent the
average of weekly samples taken during the first eight
months of the study.  December, 1978 - July, 1979
                                343

-------
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     9.5
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     8.5
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                                    345

-------
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                                346

-------
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     8.0
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                                           347

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                               348

-------
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                                      349

-------
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            337.5
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                                     350

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     TREATED SEWAGE EFFLUENT AS A NUTRIENT
     SOURCE FOR MARINE POLYCULTURE

     John H. Ryther, Woods Hole Oceanographic Institution,
       Woods Hole, Massachusetts  02543
INTRODUCTION

     A biological tertiary sewage treatment-marine aquaculture system
was developed, tested, and evaluated for two years on a "pilot-plant"
scale at the Woods Hole Oceanographic Institution's Environment
Systems Laboratory (ESL - Fig. 1).  The effluent from secondary sewage
treatment, mixed with seawater, was used as a source of nutrients to
grow single-celled marine algae (phytoplankton) in mass (35,000 gallon),
continuous flow-through cultures.   Harvest from the algal cultures
(experimentally varied from 25% to 75% of the culture volume/day),
diluted with seawater, was fed into 4o' x 4' x 5' (deep) cement raceways
containing stacked trays of shellfish.  The latter, stocked at densities
ranging from 75,000 to 150,000 animals/raceway (1,500 - 3,000 per tray)
have consisted of different species of oysters and clams, and smaller
numbers of other shellfish.

     The phytoplankton removed the nutrients from the sewage effluent,
which varied experimentally from 10 percent to 50 percent in the
effluent-seawater mixture.  The shellfish removed the phytoplankton
from the water.  Effluent from the shellfish cultures (i.e., the pond
harvest and diluting seawater) prior to its discharge was passed
through a culture of seaweeds, grown in suspended culture in raceways
adjacent to the shellfish cultures, which serve as a final polishing
step, removing nutrients not initially assimilated by the phytoplankton
and those regenerated by excretion of the shellfish and decomposition
of their solid wastes.  After initial experimentation with several
seaweed species, research was concentrated on two red algae of potential
commercial value, Gracilaria tikvahiae and Neoagardhiella baileyi (which
contain the polysaccharides, agar and carrageenan respectively).
                                       351

-------
     Solid wastes produced by the shellfish and uneaten phytoplankton
supported dense populations of small invertebrates (amphipods,
polychaete worms, etc.).  These served as food for secondary commercial
crops of marine animals, the American lobster (Homarus americanus)
and the winter or blackback flounder (Pseudopleuronectes americanus)
which were stocked in respective raceways with the shellfish.

     The primary objective of the research was to develop a biological
tertiary sewage treatment process capable of removal of all inorganic
nitrogen from secondary sewage effluent prior to its discharge into
the environment.  Earlier studies (1, 2) had established the fact that
nitrogen is the nutrient limiting and controlling algal growth in and
eutrophication of the coastal marine environment.  Thus nitrogen
removal may be considered as synonomous with tertiary sewage treatment
of effluents to be discharged to the sea.

     The second objective of the process was to develop a marine
aquaculture system consisting of a primary crop of shellfish and
secondary crops of other commercially-valuable marine organisms (sea-
weeds, lobsters, finfish), the value of which would pay for or help
defray the cost of the tertiary sewage treatment process.

Procedures and Results

A.   Algae culture and nutrient removal.

     Phytoplankton cultures were maintained continuously in five of
the six 35,000 gallon, 2,500 ft2 algae ponds (the sixth pond was held
out of production).   The culture ponds, which were approximately
50' x 50' x 3' deep, were constructed from shaped sand and fine
gravel lined with 20 mm black PVC.  The exposed edges of the PVC
liners were further covered with a 10 mm PVC "sacrificial" sheet that
could be replaced when and if sun damage occurs.  When filled to a
depth of three feet, the pond volume was 35,000 gallons.

     The cultures were kept in gentle circulation with two one-third
HP (40 gal/min)  cast iron pumps on opposite corners of the ponds.
These recirculated the culture, the return jets entering above the
surface to provide both momentum and aeration.   This action was
normally sufficient to keep the algal cells in suspension.

     Eight thousand gallons/day of effluent from the Town of Wareham,
Massachusetts, activated sludge secondary sewage treatment plant was
trucked to ESL and discharged into one of three buried 8,000 gallon
fiberglass nutrient storage tanks.  From there,  the effluent was
pumped to a headbox in the ESL mechanical room and then distributed
by gravity to the ponds.
                              352

-------
     Two to four of the pond cultures were grown on various  mixtures
of sewage effluent and seawater and the remainder on an inorganic
nutrient medium which was adjusted to the nitrogen and phosphorus
levels of sewage effluent (typically 20-25 mg/1 N and 10-15  mg/1 P).
The number of ponds operated on sewage effluent depended upon the
sewage concentration and flow rate (percent pond exchange/day)  employed.
For example, at 50 percent pond turnover with 25 percent sewage effluent
and 75 percent seawater, over 4,000 gallons/day of effluent  is required
for each pond, over half the daily supply.  Since it was desired to
obtain maximum performance data of the algal cultures without any
chance of their being nutrient limited, the usual procedure  was to
operate only two ponds with sewage effluent, at concentrations and
turnover rates comparable to the above example, particularly during
the high productivity period in summer, even although all nutrients
were not removed.

     Three times a week (M, W, F) the inorganic nitrogen and phos-
phorus input (sewage and seawater) and discharge (pond harvest) and
the particulate (i.e., algal) carbon and nitrogen in the discharge
were monitored.  From these data, daily nutrient uptake and  algal
production could be calculated and expressed on a per volume and per
area basis.  This information is summarized in Table 1 on a  seasonal
basis, extrapolated to show areal requirements in acres per  MGD of
effluent (10,000 capita) for complete tertiary treatment (nitrogen
removal).  This ranged from 26 acres in summer to 77 acres in winter,
with 19 acres for the best short-term performance in midsummer.

     In contrast to earlier experience with effluent from other
treatment plants, in which the nitrogen is predominantly in the form
of ammonia, the Wareham effluent is highly oxidized with 0-30 percent
ammonia  (depending upon time of year, performance of the plant, and
perhaps other factors), the remaining nitrogen fraction being nitrate.
This apparently does not affect algal production, though there is
evidence that the ammonia is preferentially used first by the plants
if a mixture of the two forms is present.  To more nearly simulate
sewage effluent in the cultures that were fed inorganic chamical
nutrient medium, the ammonium chloride was replaced by an equivalent
amount of sodium nitrate.  However, the latter proved unsuccessful,
possibly due to toxic contaminants in the industrial-grade chemicals
used, so practice reverted to the use of ammonium chloride.   Generally
speaking, the performance of the cultures with respect to algal growth
and nutrient removal were the same whether sewage effluent or the
chemical nutrient medium, adjusted to the same nitrogen concentration,
were used.

     During a period of approximately two months, due to malfunction
or poor operation of the treatment plant, the effluent was of poor
quality, containing large quantities of undigested suspended solids.
The resulting turbidity inhibited algal production and the dissolved
and particulate organic matter made monitoring of nutrient utilization
and algal production impossible during that period.  That experience
points out  the necessity for high quality, completely oxidized, and
clear secondary effluent for the successful operation and monitoring
of the algal growth system.
                                      353

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Table 1.  Mean phytoplankton production and nitrogen removal in effluent-enriched


cultures, on a seasonal basis.  (Figures rounded)





                                        Winter     Spring-Fall     Summer     Maximum
Mean algal production

                2
  g dry weight/m /day (ash-free)




Nitrogen removal


  g/m /day


  Ibs/acre/day (cultures 1 m deep)
Equivalent volume effluent treated


  MGD/acre




Area requirement


  acres/MGD effluent treated
 .013
77
 .026
37
 .039
26
 Assuming 24 mg N/l effluent or 200 Ibs N/million gallons effluent.
                                        12
0.3
2.7
0.6
5.4
0.9
7.1
1.2
10.8
                                                                                19
                                    254

-------
     Despite considerable effort and experimentation,  including filling
the algae ponds with ly-filtered seawater and inoculation with large
(several hundred liter)  cultures of several different  species of uni-
cellular algae, no success was obtained in controlling the species of
algae that developed and persisted in the ponds.   Cultures were always
virtually unispecific, the species varying with the season.  In winter,
at temperatures between 0° and 9°C, the diatom Skeletonema costatum
occurred.  During most of the remaining part of the year, at water
temperatures of 10° - 25°C, the diatom Phaeodactylum tricornutum,  was
the persistent alga.  During a brief period of about one month in
midsummer, when pond temperatures exceeded 25°C,  unidentified green
flagellates replaced the Phaeodactylum cultures.   It is unlikely that
the species of algae present affect rate of algal production or nutrient
utilization, so this in not an important factor with respect to the
tertiary treatment role of the system.  However,  some  species are well
recognized and documented as better food organisms than are others for
bivalve molluscs (3).  Although Skeletonema is generally regarded as one
of the better shellfish foods, Phaeodactylum is variously reported as
poor to indifferent.  The implications of that problem will be discussed
further below, but phytoplankton species control remained a chronic and
unresolved problem.

     Two of the algae ponds could be heated by circulating their contents
through heat exchangers in the laboratory.  These were operated at 15° -
20°C throughout the winter when temperatures in the unheated ponds
ranged from 0° to 5° C.   Surprisingly, there was no difference in algal
production between the heated and unheated ponds.  Seasonal variations
in algal production of three- fourfold and even species succession and
dominance are apparently due to changes in incident solar radiation,
with temperature a second order factor, at least in winter.  This is an
important finding, as it eliminates the need to consider heating an
extensive area of shallow algal ponds in winter in any commercial
application of the process in temperate latitudes.  Unfortunately,
however, the algal culture must still be heated to at least 10°C and
preferentially 15 - 20°C before it can be utilized by the shellfish.

     The continuous-flow cultures could be maintained for months at a
time with little or no maintenance.  Gradually, the accumulation of
organic matter on the bottom and the development of a fringe of epiphytic
green algae (usually Enteromorpha) at the water's edge around the
periphery of the pond causes a reduction in algal production.  This was
exacerbated if the sewage effluent contained significant amounts of
suspended solids.  When that occurred, normally at intervals of 3-6
months, the ponds were drained, cleaned, sprayed with dilute sodium
hypochlorite, sundried, refilled, and reinoculated with an adjacent
culture.  This required one or two days of effort per pond, and the new
culture could be brought on line into production in about four days.
                                      355

-------
     At pond  temperatures exceeding 15°C when Phaeodactylum was the
dominant alga in the cultures, one or more species of colorless
protozoan flagellates, roughly the same size as the Phaeodactylum
cells  (i.e.,  20-30y in diameter) appeared in the cultures and fed
upon the diatoms.  Uripredictably and very quickly the flagellate at
times  proliferated throughout the culture and eliminated the algae.
Such cultures could be discarded and restarted, as described above,
but if left alone, the flagellate population quickly subsided,
presumably through lack of food, and the Phaeodactylum population
reestablished itself in about the same time (3-5 days) that it took
to start a new culture.  Such predation did not occur often enough
to be a serious problem, but caused an undesirable interruption in
algal production when it did happen.  No means of controlling the
predator(s) were found.

B.   Bivalve mollusc culture.

     Harvest from the phytoplankton pond cultures (equivalent in
volume to the daily turnover rate of the ponds) flowed by gravity
into respective cement raceways 40'  long x 4"  wide x 5*  deep.  At its
point of entry to the raceway, the algae culture was diluted with
coarse-filtered seawater at ratios ranging from 1 to 5 parts seawater
to 1 part culture, depending upon the season and other related factors.
Reasons for the dilution were: 1) to dilute the algal suspension to
the degree necessary for the shellfish to filter and assimilate the
food organisms most efficiently, a concentration of the  order of 10s
cells/ml; 2) to provide a more rapid flow of water through the raceway
to enhance shellfish feeding; 3) to prevent the accumulation of
metabolites of the animals, particularly ammonia, to toxic levels;  and
4) through use of heated seawater when and as needed, to bring the
combined flow of algae and seawater to a temperature at  which the
shellfish would feed and grow throughout the year.   Phytoplankton will
grow equally well on heated and unheated pond cultures in winter,  as
discussed above, but the unheated cultures must be heated to 10° -  20°C
before they are presented to the animals.

     The facility did not have the capacity to raise temperatures of
the combined algal culture-seawater mixture,  at the desired flow rates,
to levels above approximately 15° C in winter.   Nor did it have the
capability of providing a range of different temperatures to the
raceway system while holding other factors (i.e.,  flow rates) constant.
Finally,  there was no capacity to cool water,  and solar  heating of  the
algal pond cultures together with the diluting seawater  could result
in peak summer raceway temperatures of 25°C.   It was therefore not
possible to control temperatures in the animal culture system beyond a
seasonal range of 15°  - 25°C.  This led to some problems in attempting
to assess shellfish growth over long periods  of time as  a function  of
other variables, such as food species,  food concentration,  flow rates,
etc.
                              356

-------
     The algae culture-seawater mixture entered  one  end  of  the  40-foot
raceway and passed in a linear flow to the opposite  end,  where  it  entered
the adjacent seaweed-stocked raceway,  for final  "polishing" of  the
effluent.  Shellfish were stocked in wooden-frame, vexar-lined  trays  (mesh
size depending upon size of the shellfish) at an initial density,  for the
1/2 - 1" seed, of 1,500 to 3,000 animals per tray, which was later to be
thinned appropriately as the bivalves  grow (Fig. 2).  The trays were
stacked vertically, 7-8 trays per stack, the raceways accommodating 8 such
stacks of trays, holding a total of some 150,000 seed shellfish.  An
airline extended along the side of the raceway on the bottom to provide
aeration and vertical mixing of the water throughout its length.  This was
found essential for mixing thoroughly  the algae culture  and diluting
seawater and preventing a stratified flow down the length of the raceway,
particularly in cold weather when heated seawater was used.  In addition,
aeration was important in maintaining  high levels of oxygen and low levels
of metabolites, particularly ammonia,  everywhere in the  raceway and
especially near the bottom.

     The initial attempt at shellfish culture involving  the stocking  of
three raceways with 300,000 seed oysters  (Crassostrea virginica) from
Flower Brothers Hatchery, Bayville, Long Island (NY) and 150,000 seed hard
clams (Mercenaria mercenaria) from Long Island Oyster Farms, Northport,
Long Island (NY) was largely unsuccessful.  Neither species grew signifi-
cantly during the following 18 months and most of the oysters died.  Two
possible explanations for this lack of success were suggested:   1) The
seed shellfish in question were stunted or otherwise inferior stocks  or
they had suffered stress or injury during transport from their sources.
2) The phytoplankton grown in the mass algal cultures, predominantly
Phaeodactylum tricornutum during most of the year, was inferior and
unsuitable as food for the shellfish.

     The first of those explanations was subsequently ruled out.  New
stocks of American oysters were obtained  from the same Long Island
hatchery that were newly-set, healthy, actively-growing seed obtained in
two separate lots during the spring.  In addition,  small lots of both
oysters and clams of the same species were obtained from other sources.
In no case did either species grow or even survive  in the  culture system.

    Since Phaeodactylum and various green algae were already known to be
poor to indifferent foods for larval and very young juvenile clams and
oysters, the second explanation therefore appeared  to be the correct one,
and success of the system appeared dependent upon the ability to control
the species and to grow other, more desirable food  organisms in the mass
algal cultures.

     At the same  time these tentative conclusions were reached, however,
small numbers of  juvenile Manila clams  (Tapes japonica)  and European
oysters  (Ostrea edulis) were obtained.  Both species survived well and
grew within the culture system and on the same  food that failed to support
£. virginica and  11. mercenaria.  Tapes  grew slowly, though apparently not
unusually so for  the species  (Fig. 3).  Ostrea  grew very rapidly, from 3.5
cm seed to 9.5 cm marketable adults in about five months (Fig. 4).
                                      357

-------
     As a result of this experience new, larger lots of (). edulis
were obtained from several sources and stocks of Japanese oysters
(Crassostrea gigas) were also obtained and introduced to the raceway
system.  The results with (D. edulis were somewhat equivocal, some
growing well and others dying, but the reason for this is believed
to be damage or injury of some of the seed during shipment (i.e.,
from as far as the U.K.).  The C^. gigas stocks all grew well.

     Thus, the earlier problem of the inability to control species
in the algal ponds and to produce phytoplankton suitable as food for
the indigenous species of oysters and clams, if not solved, appeared
to have been circumvented by use of exotic shellfish species capable
of utilizing the kinds of algae that could be mass produced.  Very
preliminary results also indicated that the local bay scallop
(Argopecten irradians) may be included among the latter group, but
evaluation of that species was hindered by scarcity of seed stock.
The interesting question of why some bivalve species but not others
can subsist on the phytoplankton "weeds" remains to be answered.

     Lack of research support for the project after the second year
prevented any quantitative evaluation of the system as a whole for
shellfish production.  Smaller scale studies during an additional
year, with a different but reduced level of support, did permit a
study of the comparative growth of six species of bivalves using
phytoplankton produced in the wastewater-enriched cultures (4).

C.   Seaweed culture.

     Seaweeds were used in the polyculture system as a "polishing
step" to remove nutrients not initially assimilated by the phyto-
plankton and those put back into the culture system by excretion of
the shellfish and other animals and the decomposition of their solid
wastes.  The objective was to achieve a nutrient-free final effluent
than would meet standards of tertiary sewage treatment at the same
time producing a crop of commercially valuable plants.

     Seaweed research was restricted to red algae of several species
that are of existing or potential commercial value for their content
of agar or carrageenan.  These included Chondrus crispus, Gracilaria
tikvahiae, Neoagardhiella baileyi, and Hypnea^ musciformis.  Of these,
Gracilaria and Neoagardhiella proved most successful.  The following
discussion concerns primarily the results obtained with Gracilaria
(Fig. 5).

     As explained in the preceding section, water leaving the shell-
fish raceways passed through the adjacent raceway in the opposite
direction where it was exposed to suspended cultures of seaweed before
being discharged back to the ocean.   The latter had the same dimen-
sions as the shellfish raceway (40'  x 4'  x 5'  deep) but were modified
with a sloping plywood bottom with a depth ranging from two feet, on
the high side to the bottom (five feet) on the low side.  An air line
                              358

-------
Table 2.  Mean seaweed production and nitrogen removal in effluent-enriched cultures, on




a seasonal basis.  (Figures rounded).
Winter Spring-Fall
Mean production
2
g dry weight/m /day (ash-free) 3 5
Nitrogen removal
g/rn /day 0.1 0.2
Ibs/acre/day (cultures 1 m deep) 0.9 1.8
Ecuivalent volume effluent treated
yGD/acre .004 .008
Area requirement
acres/MGD effluent treated 223 112
Summer Maximum

13 16

.5 .6
4.5 5.4

.022 .027

45 37
 Assuming 24 tng  N/l  effluent  or 200 Ibs N/million gallons effluent.
                                          359

-------
 on the bottom at the five-foot depth provided the vigorous
circulation needed to keep the seaweed in suspension and to bring it
continuously to the surface and to exposure to sunlight.  The sloping
bottom eliminated a dead area in the circulation cell in the corner
opposite the air line, in which the seaweed would otherwise settle
and collect (Fig. 6).

     Once a week, the seaweed population was harvested from the
raceways with dip nets, drained, and weighed.  Net production over
the previous week was removed, returning a constant starting biomass
of 50 kg/raceway.  The routine was varied experimentally during the
year, but that figure was found empirically to be optimum for maximum
daily production, which ranged from a mean of 3 grams dry weight
(organic matter) m2/day in winter to 10 grams/m2/day in summer (dry
weight is 10 percent of wet weight and contains an average of
40 percent ash in Gracilaria tikvahiae).

     Occasionally fouling organisms, in particular the green alga
Enteromorpha, invaded the seaweed cultures and grew epiphtically upon
the cultured species.  Under extreme conditions, the cultures had to
be discarded.  Epiphytic growth is probably the single greatest
problem in and constraint to commercial seaweed culture particularly
in the tropics and subtropics where conditions are otherwise ideal
for such practices.   However, for reasons not fully understood, this
problem was never a critical one in the Woods Hole experiments.

     During the second year, new experiments were initiated in which
seaweeds were grown alone, in a single-step waste recycling system,
using mixtures of seawater and secondary sewage effluent in a con-
tinuous flow-through mode of operation.  A series of plywood tanks
8' x 6' x 3' painted with white epoxy were used in these experiments
(Fig. 7).

     Maximum yields  of Gracilaria^ of 16 grams ash-free dry weight/
m2/day were achieved for short periods of time in summer, while
average yields of 3  g/m2/day in winter and 12 g/m2/day in summer
were sustained over  long periods of time.  Table 2 shows yields and
nitrogen removal capacity for the seaweeds grown on sewage effluent
and seawater mixtures in the experimental tanks described above.   As
in Table 1, the data have been extrapolated to show the potential
and areal requirement of such a system in nutrient removal per MGD
effluent.  It may be seen that seaweed production is comparable to
and, in summer, slightly better than unicellular algae production.
However, because the seaweeds contain on the average less nitrogen
per unit of ash-free dry weight (4 percent for seaweeds and about
10 percent for unicellular algae), the equal or higher rate of growth
of seaweed is more than offset by its lower capacity for nitrogen
removal per unit growth.
                              360

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     In one experiment,  three of the above seaweed tanks were operated
in series, with an input of 25 percent sewage effluent  - 75 percent
seawater mixture introduced into the first tank and then passing through
the second and third tanks at flow rates equivalent to  50 percent of  the
individual tank volume turnover per day.  The three tanks were initially
stocked with 5,000, 3,000, and 1,000 grams respectively of Gracilaria,
and the growth increment allowed to accumulate during the one-month
period of the experiment.  Inorganic nitrogen and phosphorus were moni-
tored in the water entering and leaving each of the tanks.  The data
from this experiment is summarized in Table 3, where it may be seen that
the three tank cultures progressively removed 99 percent of the incoming
nitrogen.  Nitrogen deficiency of the Gracilaria in the third tank was
evident both in its pale yellow coloration, in contrast to the deep
reddish-brown color of the plants in the first tank, and in its carbon:
nitrogen ratio, which was 28 in contrast to 10 in the first tank. This
has some practical significance, as the commercial product of the seaweeds
(agar in Gracilaria) is elaborated more rapidly and to  a greater degree
in nitrogen-deficient plants.  In a commercial seaweed  culture application,
using a raceway or channel-type culture configuration with a linear  flow
of water and nutrients, the seaweed should presumably be moved downstream
in the system, away from the source of nutrients, and harvested from  the
far end following a period of exposure to nitrogen-free conditions.
Further evaluation of the production of the seaweeds and their hydro-
colloids in the wastewater recycling system is presented in a separate
report (5).

D.   Nutrient removal efficiency of the system as a whole.

     As pointed out earlier, algal pond cultures were operated during
the first year deliberately at nutrient (sewage effluent) concentrations
higher than could be completely utilized by the phytoplankton.  This  was
done to develop information on the maximum potential growth and nutrient
assimilative capacity of the algae under non-nutrient limited conditions.
The amount of nitrogen taken up by the algae from solution or the amount
contained in the algal harvest, by direct measurement,  could then be
used to calculate  the daily assimilative capacity of the system and
this, in turn, to calculate the daily input of sewage effluent per unit
area of algal pond for complete nitrogen removal.  That information,
based on a year's observation, is presented in Table 1, also including
the comparable data for a seaweed-based tertiary treatment system.

     The above data, interpreted in terms of  the ESL pond culture
system, means that complete nitrogen removal  could be expected in
winter operating at a 25  percent pond volume  turnover per day with an
input of 10 percent sewage effluent and 90 percent  seawater.  In spring
and fall,  the effluent strength can be  increased to 20 percent or the
turnover rate doubled  (50 percent), resulting in either case in doubling
the nutrient input rate.   In  summer, the system should be able to
assimilate completely the nitrogen from 30 percent  effluent - 70 per-
cent seawater mix  at 25  percent turnover,  or  a 10 percent effluent -
90 percent seawater at 75 percent turnover rate per day.
                                       361

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Table 3.  Nitrogen removal in experimental  seaweed  (Gracilaria  tikvah iae)  tanks  operated


in series under steady-state, continuous  flow-conditions.
Tank No.   Effluent N concentration     % N removal     Seaweed  production    C:N  in  seaweed
                                                          2
                                        (cumulative)    g/m /clay  (ash-free)
                     0.96                    60                 3.4                  10
                     0.07                    77                 2.5                  12
                     0.02                    99                 1.2                  28
 Initial N concentration  (input  to Tank  1)  =  2.41  ppin.
                                             362

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     Since ±t is costly to pump seawater,  the higher effluent concen-
tration at the lower exchange rate is the  more economical mode of
operation.  There is some evidence, however,  that stability of the
cultures may be enhanced by low nutrient levels at high turnover rates,
so the costs of labor (for cleaning and restarting cultures)  and of
building and operating stand-by cultures to provide for down-time  may
exceed the cost of pumping additional seawater.

     Table 4, shows typical steady-state mass flow of nitrogen through
the three-step system under late spring operating conditions as defined
above.  Of the nitrogen (nitrate, nitrite, and ammonia) daily entering
the pond as sewage effluent (84 grams) and seawater (Ig), over 98  per-
cent (83.4 g) was removed by the phytoplankton.  The remaining 1.5g,
together with the algae, was fed to the shellfish raceway, where it was
mixed with twice its volume of seawater.  Since the latter contained  the
same concentration of inorganic nitrogen as the pond effluent (0.04 ppm),
the seawater contributed twice as much nitrogen as the effluent (total
4.5 g).  To this, the shellfish raceway added 22.5 g of dissolved
inorganic nitrogen through excretion, decomposition, or other sources,
roughly 25 percent of the amount that entered the raceway as phytoplank-
ton.  Of the total output of 27 g nitrogen from the shellfish raceway,
18 g were removed by the seaweeds, leaving a final residual of 9 grams,
10 percent of the initial input of the sewage effluent and seawater,  for
a total removal efficiency of the system as a whole of 90 percent.
Since the seaweed removed two-thirds of the regenerated nitrogen,  it
could be assumed that expansion of the seaweed culture by one-third
(from 160 ft2 to 240 ft2 in the pilot facility) would result in complete
nitrogen removal of the final effluent.

E.   Culture of secondary animal crops.

     Solid wastes (feces and pseudofeces) produced by the shellfish
and/or uneaten phytoplankton cells which settle out from suspension in
the shellfish raceways provided sources of food for large quantities of
several species of small, invertebrate detritovores that presumably
entered the system as larvae in the coarse-filtered seawater use to
dilute the phytoplankton pond harvest.  Prominent among such inverte-
brates were amphipods  (Corophium, Jassa, and Gammarus), polychaetes
(Capitella capitata), bryozoans, tunicates, and mussels.  This small
invertebrate fauna served the dual purpose of preventing the accumula-
tion of solid organic wastes in the raceways and providing a source of
food for  secondary crops of carnivores or omnivores of potential
commercial value.  The latter included the American lobster  (Homarus
americanusj and the winter or blackback flounder  (Pseudgpleuronectes
americanus)  (Table 5).

     In July, 474 juvenile  (0 to 1 year class) flounder were collected
locally and  stocked in one of the  oyster raceways.  Their size distri-
bution was,  of course, bimodal for the two-year classes, but averaged
7.0 cm.   In  October,  the raceway was drained and 124 fish recovered,
averaging 11.0 cm in  length.  The  following April, 69  fish were recovered,
                                       363

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Table 4.  Mass flow of inorganic nitrogen (ammonia, nitrite, and nitrate)




through the phytoplankton-oyster-seaweed system.









                                                     grams N/day





1.  Phytoplankton pond input




         sewage effluent                                 84




         seawater                                         1        85





2.  Phytoplankton pond output                                       1.5





3.  Shellfish raceway input




         phytoplankton pond harvest                       1.5




         seawater                                         3.0       4.5





4.  Shellfish raceway output                                       27




         (= seaweed raceway input)





5.  Seaweed raceway output




         (final effluent from system)                               9.4







    Total N removal efficiency (including seawater)                89.3%




    Effluent N removal efficiency                                  93.6%
                                     364

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Table 5.  Growth and survival of winter flounder and American lobsters in




oyster raceways.

Days
0
120
300
Days
0
90
240
Winter flounder
Number
474
99
69
(Pseudopleuronectes americanus)
% survival
	
21
14.5
American lobster (Homarus americanus)
Number % survival
390
256
124
	
66
32

Size (mm)
70
110
167
*
Size (mm)
9.0
13.4
25.0
 *
  Carapace length.
                                          365

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averaging 16.75 cm in length.  The surviving fish thus more than
doubled in size in 9 months.  If the observed linear growth rate were
to continue, the fish would reach a marketable size of 25 cm (1/2 -
1 Ib) in another 9 months, or 18 months from the time of stocking as
juveniles.

     Egg-bearing lobsters were obtained from commercial fisherman, by
special permit, and were held in the laboratory until the eggs hatched
(i.e., in spring, when water temperatures reach 15° - 20°C).   The
larvae were transferred to specially-constructed larval rearing tanks
where they were fed live or frozen brine shrimp (Artemia salina).
After metamorphosis to juvenile lobsters (10 - 14 days), they were
segregated into small containers, to prevent cannibalism, and fed the
same food until they had molted an additional 3-4 times and attained
a mean size of 9 mm carapace length and 0.18 grams.  A total of 390 of
these lobsters were then stocked in September in segregated (screened-
off) portions of two oyster raceways, each group together with two
stacks (16 trays) of oysters.  The following April, a total of 124
lobsters were recovered which had a mean size of 25 mm carapace length
and a mean weight of 18 grams.  These ranged widely, however, in their
size distribution, from 10 to 52 mm carapace length.  The larger
individuals, some 150 mm total length, attained a size in eight months
that is not reached by wild lobsters in New England in less than three
years, and is comparable to the best growth obtained with segregated
lobsters held in captivity at elevated temperatures and fed artificially,
                               366

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                              References
1.   Ryther, J.  H. and W.  M.  Dunstan.   1971.   Nitrogen,  phosphorus and
     eutrophication of the coastal marine environment.   Science 171:
     1008-1013.

2.   Goldman, J. C., K. R. Tenore and  H.  I.  Stanley.   1974.   Inorganic
     nitrogen removal in a combined tertiary treatment-marine aquaculture
     system.  Part II.  Algal bioassays.   Water Research 8:  55-59.

3.   Ryther, J.  H. and J.  C.  Goldman.   1975.   Microorganisms as food in
     mariculture.  Annual Reviews of Microbiology 29: 429-443.

4.   Mann, R. and J. H. Ryther.  1977.  Growth of six species of bivalve
     molluscs in a waste recycling-aquaculture system.   Aquaculture 11:
     231-245.

5.   DeBoer, J.  A. and J.  H.  Ryther.  1978.   Potential yields from a
     waste-recycling algal mariculture system.  In R. Krauss, Ed.  The
     Marine Plant Biomass of the Pacific Northwest Coast.  Oregon State
     Univ. Press.  397 pp.
                                      367

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                                 Figure Legends
Figure 1.      Environmental Systems Laboratory,  Woods Hole Oceanographic
               Institution.
Figure 2.      Wooden frame, vexar-mesh trays with seed oysters in shell-
               fish raceway.
Figure 3.      Growth of Tapes japonica after five months.


Figure 4.      Growth of Ostrea edulis after five months.
Figure 5.      The red seaweed Gracilaria tikvahiae grown in ESL raceway
               system.
Figure 6.      The ESL raceway system with shellfish raceways covered and
               seaweed raceways exposed.
Figure 7.      Plywood tanks used for growing seaweeds directly on sewage
               effluent.
                              368

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FIGURE 2
  370

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        FIGURE 7
375

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            THE SOLAR AQUACELL SYSTEM FOR PRIMARY,  SECONDARY

                 OR ADVANCED TREATMENT OF WASTEWATERS

      William C. Stewart, Director of Research and  Development,  Solar
         AquaSysterns, Inc.*

      Steven A. Serfling, President, Solar AquaSystems, Inc.*
      The Solar AquaCell process is an aquaculturally derived wastewater
treatment system which integrates proven wastewater treatment elements
to allow greater process control, higher quality effluent, and reduced
land area as compared to conventional wastewater lagoons.  Three AquaCell
pond systems, anaerobic, facultative, and aerobic, all containing high
surface area bio-film devices, can be used in series to achieve primary,
secondary and/or advanced treatment, respectively.  Three years of
pilot scale demonstrations have shown that conservative design practices
can be used while also achieving reduced construction, operation and
maintenance costs, minimal solids handling, low energy demand, and low
operator skill requirements.  The use of a multiple series of controlled
cells allows a high degree of design and operational flexibility for
meeting various effluent quality objectives.  The City of Hercules'
Solar AquaCell Treatment System is also described.
      * P.O. Box 88, Encinitas, California  92024
                                     377

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INTRODUCTION

     Reliability and stability in meeting discharge standards must be
the primary criterium for every wastewater treatment process.  In cases
where the effluent is to be discharged, maintenance of these standards
is critical in preventing degradation of receiving waters and ground-
water supplies.
     It has been estimated by the U.S. Environmental Protection Agency
that conventional secondary quality treatment plants in the United
States are failing to meet discharge criteria 30-50% of the time (1-2).
Designers of these processes blame municipalities and correlate the
lack of reliability and stability primarily on inadequate operation and
maintenance budgets and poor operator training (3).  Correction is said
to require an increased financial commitment from the municipality
managing the treatment plant.  However, we must face the fact that be-
cause of the changing economic conditions, additional 0 & M support
from an already hard-pressed local government will be difficult to find.
Also, the increasing cost of energy, coupled with the high energy de-
mand of most wastewater treatment processes is adding a serious burden
to operating costs.  Thus, design criteria for new wastewater treatment
processes must also include low 0 & M, simplicity of operation, and low
net energy requirements.
     In many areas of the world, including parts of the United States,
water supplies are not adequate to meet projected, and in some cases,
even present demand.  As recycling and/or reuse of treated wastewater
becomes economically advantageous, the reliability and stability of
treatment processes becomes even more critical to prevent release of
disease or toxic materials (4).  Attempts to provide cost effective
advanced treatment of wastewater for reuse by modification of conven-
tional systems have not been successful, primarily due to excessively
high capital and operation and maintenance costs and the complexity
of the process trains to achieve the necessary reliability (5-6).  As
a result of these failures, the U.S. Environmental Protection Agency
is now requiring special scrutiny of all AWT projects (6).  Thus,
despite the potential and need for reuse of wastewaters, recycling has
suffered a severe setback due to the application of an inappropriate
technology.
     In addition   to recycling of water, the recycling of the nutrients
from wastewater appears necessary in  the very near future if food prices
and agricultural productivity are to meet population needs.  The pro-
duction of expensive, petroleum derived fertilizers while discharging
valuable nitrogen and phosphorous laden wastewater cannot make sense
for long.  For these and additional reasons, there is a growing  interest
in alternative technologies for wastewater treatment.  Among those which
have demonstrated excellent potential  for meeting  the new criteria are
aquaculture and aquaculture-derived wastewater  treatment systems.
     The major advantages of most aquaculture treatment processes are
low operation  and maintenance costs,  simplicity of operation, and poten-
tially greater reliability and stability.  Henderson and Wert (7) have
calculated  that aquaculture wastewater  treatment  systems can save up  to
90% of  the  total  life cycle  treatment  costs when  compared  to conven-
 tional  technologies.  Duffer and Moyer  (8) provide an excellent  review
of  the  status  and potential of aquaculture processes for municipal
                                     379

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wastewater treatment,  for wastewater reuse and/or recycling purposes,
managed aquaculture systems offer the advantages of high dilution of
toxic wastes and longer retention times to reduce upset potential.
Potentially toxic wastes can also be removed without the addition of
chemicals (9-10), thus reducing operation costs.  However, the chief
limitation of most aquaculture type processes has  been high land
area requirements and/or the lack of process control for achieving
advanced treatment objectives.
     In order to provide an alternative between the extremes of existing
high energy conventional technology and simple, low cost, algal lagoon
methods, Solar AquaSystems, Inc. has developed and extensively tested
over the past 4-year period, a high rate, controlled environment aqua-
culture wastewater treatment process called the Solar AquaCell System.
THE SOLAR AQUACELL SYSTEM

     The basic design parameters of the Solar AquaCell System have been
described previously (11).  The design principles of the AquaCell
system are based on an integration of the best features of lagoon or
aquaculture systems (i.e. low operation and maintenance costs, low
energy requirements, high dilution factors, toxin removal capabilities,
nutrient recovery), with the reduced land area requirements, increased
process control,  and advanced treatment capability of conventional,
higher technology systems.
     The AquaCell process consists of an integration of the following
basic elements:  (Fig.  1)
     1.  a series of multicell lagoons.
     2.  a diffused aeration system for maintaining proper dissolved
oxygen concentrations,  and to provide for gentle stirring and partial
mixing of the wastewater past the aquatic plant surface area and BioWeb
substrates.
     3.  high surface area fixed-film substrates (activated BioWeb
substrates) to provide habitat for the biofilm and associated detriti-
vore community.
     4.  the use of floating aquatic macrophytes, particularly water
hyacinths and duckweeds, for achieving advanced treatment and recovery
of nutrients.
     5.  tensile structure greenhouse pond cover to provide cost
effective insulation for capture of solar heat  in cooler climates and
to reduce evaporative water losses.
     6.  a simple solar heat exchange system for transferring solar
energy from the air phase to the water phase in order to increase pond
temperature, metabolic rates, and thus treatment efficiency.
     The function of each component is described in further detail in
the following section,

AquaCell Component Description

     1.  The Multicell Lagoon Process
     The use of lagoons for wastewater treatment processes is a proven
and well documented technology (12).  In these applications, lagoons
offer the following advantages:
                             380

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                                       FIGURE  1
                      SECTION  VIEW  -  SOLAR  AQUACELL SYSTEM
                                                                 COLSLE  POLYETHYLENE
                                                                  A! 3  INFLATED ROOF
              ATER HYACINTHS
                DIFFUSED
                AERATION
3IO-WEB  SUBSTRATES
  FOR ATTACHED
 MICROORGANISMS
   SLJOGE
   DIGESTS
ANAEROBICALLT
CONCRETE  POST
   FOOTING
                         GENTLE MIXING
                                                   381

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     A.  Lagoons are relatively inexpensive to construct and maintain
and have a potentially greater life cycle than concrete tanks.  Properly
designed and sealed, leakage and consequent groundwater contamination
problems from lagoons can be avoided.
     B.  Lagoons offer major safety factors for wastewater treatment.
Conventional biological wastewater treatment designs have retention
times of only a few hours.  Consequently, toxic shock loads receive
little initial dilution, and can cause poisoning and cessation of
biological activity with subsequent discharge of high amounts of un-
treated or poorly treated wastewater.  Lagoon systems, with their
longer retention times and greater volumes, provide rapid and adequate
dilution of toxic materials with consequent protection of the biolog-
ical treatment components of the system.  In addition, the extended
retention times provide more complete removal of toxic materials and
pathogens.
     Disadvantages of conventional lagoon systems include high land
area requirements and, because of the high water surface area, re-
duced control over the treatment process.  In addition, problems with
algal growth within lagoons create difficulties in meeting effluent
requirements for suspended solids and reduces seasonal reliability.
     The Solar AquaCell system uses a series of lagoons modified for
smaller size and improved hydraulic design.  This approach is made
possible by the use of high surface area BioWeb substrates and aeration
within the lagoon as discussed below.

     2.  Diffused Aeration
     The shallow AquaCell lagoon process is designed to use a low
energy, low pressure, high volume diffused aeration system for the
purpose of maintaining proper dissolved oxygen concentrations through-
out the system, and, providing gentle stirring and partial mixing of
the wastewater past the BioWeb substrates and aquatic plant root sur-
face area.  Air consumption of the Solar AquaCell system is signifi-
cantly reduced in comparison to conventional processes through imple-
mentation of the following strategies:
     A.  Use of the anaerobic AquaCell for initial treatment of raw
wastewater.   The BOD loading on the subsequent aerated ponds can be
reduced 50-70%.
     B.  Use of a facultative AquaCell following anaerobic pretreat-
ment.  Since the facultative cell is not subject to shock loadings of
raw wastewater, and is handling a reduced BOD and suspended solids
load, aeration requirements in this cell are reduced as compared to
conventional practice.  In addition,  the maintenance of an anaerobic
bottom layer in the facultative pond bottom provides for stabilization
of settled organics without the consumption of additional energy.

     3.  BioWeb Substrates
     The use of biologically active substrates or bio-films,  to provide
increased surface area for microbial growth is standard practice in
conventional biological treatment processes.   For example,  activated
sludge plants and oxidation ditches use suspended particles of sludge
to provide this increased surface area;  trickling filters use rock,
redwood, or plastic media;  rotating biological contractors use plastic
disks rotated through the wastewater stream,  all for the purpose of
                              382

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growing bacteria and associated microorganisms.
     Solar AquaSysterns,  Inc.  has pioneered the use of vertically
oriented bio-films for use in lagoon type processes.   Four types of
substrates have been developed to optimize treatment throughout the
process train.  For example,  flat sheet bio-film appears to optimize
conditions for BOD reduction in high loading conditions, while mesh
type bio—films in various configurations optimize conditions for
nitrification and denitrification.  Design factors are 2-3 ft.  of
surface area per gallon treated for secondary treatment while 4-6 sq.
ft./gpd is required for various levels of tertiary treatment (11).
Because of the relatively low cost of BioWeb substrates, it is econom-
ical to design lagoon processes with much higher bio-film surface area
to loading rate ratios and with longer retention times than found in
conventional bio-film processes, thus resulting in a more conservative
design than conventional technologies.  Additional advantages of the
Solar AquaSystems' BioWeb include:
     A.  No structures are required to support the BioWeb, since it is a
low density floating material and only needs to be anchored at the
bottom.  It can be easily added to lagoon systems without the cost of
additional components.
     B.  Reduction of BOD and suspended solids is achieved also by
physical means, with the BioWeb substrates acting as a barrier to in-
crease coagulation and sedimentation of the suspended organics, which
are then digested anaerobically on the pond bottom.
     C.  The vertically suspended, buoyant BioWeb substrates maintain
the bacterial film in suspension without the need for energy for
aeration as is required for the activated sludge process and oxidation
ditches,or for movement through the water phase as is required for
rotating biological contactors.  Similarly, the trickling filter re-
quires high pumping costs to lift and recycle sewage through the filter
media.
     D.  The BioWeb substrates also provide extensive habitats for
grazing organisms which consume, concentrate, and metabolize the
organic and inorganic detritus material adhering on the BioWeb sub-
strates.  Because of their flexible nature and vertical orientation,
BioWeb substrates are self-cleaning, thus eliminating blockage problems.
For this reason, BioWeb equipped systems are capable of treating higher
loading rates than conventional biofilm processes,
     E.  The BioWeb substrates act as channeling devices to minimize
short  circuiting in lagoons and improve plug flow conditions for
optimal treatment efficiency,

     4.  Floating Aquatic Macrophytes
     To date, the most promising aquaculture wastewater treatment
systems have used floating aquatic macrophytes, primarily water hya-
cinths and duckweeds.  These plants offer the following advantages
for treating wastewaters;
     A.  Stability and hardiness - extensive studies by Wolverton  (9)
with water hyacinths and Hillman and Culley (13) , and Harvey and Fox
 (14) with duckweeds have demonstrated that both plants are very stable
and hardy organisms that can survive and rapidly multiply under varying
environmental conditions.  In  fact, both plants have been shown to
                                      383

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greatly  increase both average and  total productivity when cultured in
wastewater  treatment ponds.  They  can  tolerate widely fluctuating
nutrient loading rates,  solar input, fluctuations in water chemistry
such  as  pH,  carbon dioxide, alkalinity, and are not affected by toxic
compounds (heavy metals,  chlorinated hydrocarbons, phenols, etc.) at
concentrations  typical of municipal wastewaters.  Studies by Wolverton
(9) have shown  that water hyacinths can be used for concentration, re-
moval, and  potential recycling of  a variety of heavy metals occurring
in many  industrial effluents.
      B.   Provide shade to prevent  algal growth - floating aquatic macro-
phytes eliminate high effluent levels  of suspended solids and BOD
caused by algal cells because the  sunlight penetrating through the
plant fronds is insufficient to allow  significant phytoplankton growth.
      C.   Ease of harvest  - the aquatic macrophytes are relatively easy
to harvest  compared to unicellular algae.  Duckweeds can be removed
by a  surface skimming device as part of the pond overflow mechanism.
Hyacinths, when harvested on a regular basis, can be removed by an in-
pond  harvesting boat, chopped, and pumped as a slurry to the reuse
area.
      D.   High reuse potential - water hyacinths and duckweeds offer
numerous reuse  possibilities, including high protein animal feeds,
conversion  to rich organic compost or fertilizer, or conversion to
methane  gas  or  methanol.  Water hyacinths grown in sewage lagoons
typically average 20% protein (9), while duckweeds have been shown to
average  over 40% protein  (13).  Studies by Wolverton (9) and Lecuyer
and Martin  (15) have demonstrated  that one acre of water hyacinths can
produce  an average of 200-300,000  cubic feet of methane gas per year.
      E.   Advanced tertiary quality effluent can be economically
achieved - due  to the stability, high productivity, shading, and
relative ease of harvest, floating aquatic macrophytes can contribute to
advanced tertiary quality water with relatively little capital or
operating costs.  The plants convert dissolved nutrients into a fixed
biomass  which is stable until harvested, and does not recycle or return
to the effluent or lagoon bottom to create problems at a later time.
This  controlled aquaculture process does not require the expensive
energy,  chemicals, or maintenance  costs which are typical of conven-
tional advanced wastewater treatment systems.  In addition, capital
costs can be  significantly lower.

      5.  Tensile Structure Greenhouse Covered Ponds
     The organisms involved in all biological wastewater treatment
processes (i.e. bacteria, protozoans, fungi, rotifers,  amphipods,
macrophytes,  algae, etc.) are poikiothermal, that is,  their metabolic
rate  follows  the ambient  temperature of their environment.   Generally,
changes  in their metabolic rate, and consequently, the rate of waste-
water treatment at varying temperatures, can be estimated by the
van't Hoff-Arrhenius equation.  This states that for every 10° C change
in temperature, the reaction changes by a factor of 2.   Thus, a biolog-
ical  treatment  process operating at 20°C will function at twice the
effectiveness of one operated at 10°C, or conversely,  require one-half
the treatment area.
      In  order to take advantage of the normally high temperatures of
                              384

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Incoming wastewater, which vary from 10 to 21.19C (16), the Solar
AquaCell system is designed to utilize relatively low cost, tensile
structure type greenhouses specifically designed for covering waste-
water ponds.  Advantages of using these structures include:
     A.  Reduced land area due to increased operating temperatures,
especially in areas with moderate to severe winters.  Combined with
solar heat transfer Csee following section 6),  which can be consider-
able even on cloudy days, it is possible for a greenhouse covered pond
system in northern climates to have average operating temperatures of
12-179C during a four-day retention period, thus maintaining system
reliability and stability while reducing land area costs.
     B.  Year-round process stability, since most aquatic plants,
particularly water hyacinths, cannot survive or grow if exposed during
winter seasons in most temperate climates.  Use of the greenhouse pond
cover permits maintenance of water temperatures necessary for continual
growth of most macrophytes in areas of moderate winter temperatures.
Duckweeds, in particular, survive naturally in cold climates and, by
using greenhouse covers, are capable of growth throughout the year in
a cold climate treatment system.
     C.  Increases in total dissolved solids due to evaporation is a
problem in arid regions.  Use of macrophytes for wastewater treatment
increases the rate of evapotranspiration still further.  Use of green-
house covers over the treatment ponds controls evapotranspiration and
prevents the increase in TDS in the treated wastewater.  Thus, the
greenhouse pond cover can be particularly cost effective where water
is a valuable commodity.
         In cold-climate situations, snow loads are not a serious con-
cern because the warm temperatures within the greenhouse (including
between the two plastic roof membranes), and in the pond, which acts
as a giant heat reservoir, quickly melt any snow accumulating on the
roof membrane.  Greenhouses are commonly used in the hydroponic veg-
etable and decorative plant industry in northern climates without
experiencing serious snow load problems.  Greenhouse systems utilizing
double layer, air inflated membrane roofs have particular advantages
in retaining pond heat.  It has been demonstrated that such roofs can
reduce heat loss to 50% of greenhouses with single layer roof glazings
consisting of glass, fiberglass, or polyethelene (17).

     6.  Solar Heat Exchange and Sprayer System
     The solar heat exchange system, used in conjunction with the green-
house covers, transfers solar energy from the air phase inside the
greenhouse into the water phase in the treatment ponds.  This system
utilizes low volume misting nozzles and a thermostatically controlled
pump to recycle treated, disinfected water from the final effluent.
It has proven its effectiveness in increasing water temperatures as"
well as aquatic plant vigor in both wastewater and aquacultural appli-
cations at  the Solar AquaSysterns laboratories.
 RESULTS  OF PILOT  STUDIES TO DATE

 Description  of Demonstration Facility
                                     385

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     In order to develop, test and fine tune the AquaCell process,
Solar AquaSystems, Inc. has constructed and operated two facilities
in the San Diego area.  The first, located in Solana Beach, was oper-
able on an  intermittent basis from September, 1976 to March, 1978.
At this first facility, the Solar AquaCell proved capable of treating
sewage to a tertiary quality within 4-6 days retention time under
varying nutrient loading conditions.  Performance results from testing
at the Solana Beach facility are provided in a previous publication (11),
In June, 1978, a new demonstration and testing facility was constructed
at the San Elijo treatment plant in Cardiff, California.  The San Elijo
treatment plant is operated by the County of San-Diego and provides
primary treatment and ocean discharge of 7,600 m /day (2 mgd) of
domestic sewage.  The Solar AquaCell facility at Cardiff, which is
currently in operation, consists of a 3-stage AquaCell system containing
a series of five cells operated by gravity flow (Fig. 2 ).   It was de-
signed to approximate full scale AquaCell design parameters in terms
of surface to volume ratios, waste loading rates, aeration rates,
aquatic plant cover, etc., and to incorporate various design improve-
ments based on experience at the Solana Beach facility.  The Cardiff
demonstration system has been treating an average of 11,350 liters
(3,000 gpd) per day since July, 1978.
     The first or primary treatment stage (Cells 1 & 2) is operated
anaerobically and designed for advanced primary treatment of raw
sewage.  The first cell acts as a sedimentation basin, with upflow
percolation of incoming raw wastewater through an actively respiring
sludge layer.  The volume of this cell is approximately 4,500 liters.
The second cell contains high density, vertically suspended BioWeb
substrates which function as fixed bio-films to further reduce BOD,
TSS, and to optimize methane production.   Both anaerobic primary cells
have floating rubber covers for methane gas collection, odor control
and heat retention.  Total retention time for the two-stage anaerobic
AquaCell averages 14 hours (6 hrs.  - Stage 1; 8 hrs.  - Stage 2).
     The following secondary and tertiary treatment AquaCells consist
of three equally sized cells, each 2.4 meters wide, 4 meters long and
1.7 meters deep of approximately 16,000 liter capacity each.  These
three tanks are plumbed with header pipes at each end to evenly dis-
tribute flows and minimize short circuiting.   The influent and effluent
piping to each tank is plumbed to also allow either parallel or series
flow operations  but to date has only been operated as series flow.
Diffused aeration is provided by a small  air compressor,  (0.5 hp), and
submerged air diffuser pipes extending the length of  each aerated cell.
The first aerated cell (Cell #3) also contains a 0.06 hp surface
aerator.
     The secondary treatment cell (Cell #3)  is operated under faculta-
tive conditions to allow further sedimentation and anaerobic digestion
in the benthic layer to reduce overall energy requirements.   No plant
cover is used in this facultative AquaCell,   Treatment is achieved
through sedimentation and microbial activity provided by  the BioWeb
substrates,  and maintenance of dissolved  oxygen at 1  to 3 ppm.
     Cells 4 and 5 of this series are operated to achieve various levels
of advanced tertiary treatment.   In addition to the submerged BioWeb
substrates,  Cells 4 and 5 also contain floating aquatic plants,  either
                             .386

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                                                                        FIGURE 2
CJ
00
                       PROCESS  FLOW  DIAGRAM-SOLAR  AQUACELL  DEMONSTRATION  UNIT
                                                                 Cardiff,  California
        2-STAGE ANAEROBIC CELL

 Q Sedimentation,  © Methane generation t
    digestion 1       BOD, COD reduction   i
    acid formation     stage               Gas vent
    stage              ^-Floating cover

kAU
SFHAGE
INFLUENT "  —I
                                                     AEROBIC AQUACELL 1
                                                      (Facultative Stage]
                                                                   AEROBIC AQUACELL 2
AEROBIC AQUACELL 3
                                                                                               Floating Aquatic Plants
                                                                                        x»" (Duckweeds, hyacinths, water
                                                                                                                     ^.
Upfloo percolation
through sludge.     Self-cleaning bio-film
                substrates for methanogenlc
                bacteria
                                                                                          Aeration pipe'
                                                                                          and dlffusers
                                                                                                                                        Slot.
                                                                                                                                        Sand Filter
                                                               ^Activated Bto-Ueb Substrates
                                                                                                                            Polished
                                                                                                                            effluent

-------
water hyacinths (Eichbrnia crassipes) and/or duckweeds (Lemna sp.,
Spirodela sp.. Wolffla spp.) and are maintained under aerobic condi-
tions with 3-6 ppm of dissolved oxygen.  The plants function to shade
out growth of planktonic algae, remove nutrients, trap suspended solids,
and collect and remove a portion of the invertebrate food chain when
harvested.  The floating plants provide the additional advantage of
resource recovery, since they are a convenient method for converting
dissolved and particulate wastes into either methane gas, organic
compost for soil application, or animal feeds.  However, previous
studies (18) have shown that the BioWeb substrates are responsible for
80% or more of the treatment that takes nlace in these cells.  The slow
sand filter (4-8 liters per minute per m ) at the effluent end of Cell
#5 functions to trap any invertebrate organisms, aquatic plant debris,
or resuspended detritus exiting through the effluent pipe.  Total re-
tention time for the five cell system averages 4.8 days at the 11,350
liter/day flow rate.  Secondary treatment levels are achieved with a
2-day retention time (anaerobic cells 1 and 2 and facultative cell 3).
     The entire five cell series is enclosed within a greenhouse which
insulates  against heat loss while collecting solar heat in order to
maintain higher winter operating temperatues.  Water misting nozzles
(solar heat exchange system) above cells 4 and 5 spray treated effluent
water to transfer solar heat into the AquaCells, increase aquatic plant
vigor, and protect plants from overheating during summer periods.
     The facility at Cardiff has been utilized as both a demonstration
and research laboratory, testing the effect of various levels of aera-
tion, harvesting and management schedules, sludge deposition and di-
gestion rates, BioWeb material and form, etc.  Due to its small size,
the facility can be looked upon as a worst case condition, since aqua-
culture processes in general attain greater stability through greater
size.

Results

     Data collection and analysis were performed by the University of
San Diego Environmental Studies Laboratory, funded in part by a con-
tract from the U.S, Department of Interior, Office of Water Research
and Technology (19).  In the period from July 14, 1978 to August 31,
1979, a total of 440 suspended solids, 339 BOD, 497 ammonia,  388
nitrite, 481 nitrate,  and 271 turbidity measurements were taken on a
regular basis.  Additional measurements of dissolved oxygen,  pH, COD,
TOC, coliform, heavy metal, chlorinated hydrocarbon, and other tests
were also performed.
     Data showing performance analysis of the Cardiff AquaCell Demon-
stration Laboratory has been presented previously by Serfling and
Alsten (11), and Stewart,  et al.  (20)  and will not be covered in its
entirety in this paper.  However, additional, more current data,
especially that concerning the anaerobic AquaCell and the attainment
of secondary treatment by use of the anaerobic and facultative AquaCells
in series without aquatic plants will be discussed.
                              388

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Primary Treatment

     The anaerobic AquaCell at Cardiff, with a six-hour retention time
in the first stage and an eight-hour retention time in the second or
bio-film stage, has been achieving an average BOD removal of 50%
(standard deviation - 27.7) and a suspended solids removal of 88.7%
(standard deviation - 12.6) over the ten month period for which data
is presented (Table 1).  Raw influent BOD levels during this time have
ranged between 480 and 130 ppm with a median value of 218.4 ppm.
Suspended solids in the raw influent have ranged between 628 and 140 ppm
with a median value of 247.9 ppm.  In addition, COD reduction has aver-
aged 72.6%, turbidity - 49.6%, TOG - 81.4% and fat and oil reduction -
58%.  The pH of the influent raw wastewater has varied between 6.8 and
7.9 with a mean of 7.3.  Effluent pH has ranged between 6.6 and 7.2
with a mean of 6.9.  These treatment levels have been achieved through
use of a completely passive system requiring no energy input or moving
parts, and have been remarkably stable.

Secondary Treatment Using the Anaerobic - Facultative AquaCell
Combination

     Effluent from the Anaerobic AquaCell flows next into the facul-
tative AquaCell for secondary level treatment  (see Figure 2 for
process train).  This aerated cell has a 1.4 day retention time and
contains no aquatic plant cover, treatment being entirely by micro-
organisms on the BioWeb surface.  Tests showed that floating aquatic
plants in this AquaCell could improve  treatment slightly, but surface
oxygen exchange was also impaired, requiring increased energy costs
for aeration.  Suspended algae blooms  are not a problem in this cell
without the floating macrophyte cover  for shade due to the short re-
tention time.  Results showing the performance of  the combined primary
and secondary AquaCells is presented in Table  1 and Figures 3-5.
Figure 3 is a graphical representation of Table 1  data for BOD, sus-
pended solids and  turbidity and removal for the anaerobic-facultative
AquaCell combination.  Figures 4 and 5 show average monthly values for
influent raw wastewater, anaerobic AquaCell effluent and facultative
AquaCell effluent  for BOD and suspended solids respectively.  As can
be seen, secondary discharge standards have been achieved on a reliable
basis for the  ten-month period represented.
     BOD loading rates for the anaerobic AquaCell  were equivalent  to a
high range of  5230 kg/ha/day  (4,667 Ibs/acre/day), and a low of 1,200
kg/ha/day (1,072 Ifas/acre/day) with a  mean value of 2,380 kg/ha/day
(2,128 Ibs/acre/day).  As expected, the higher the BOD loading applied
to  the anaerobic AquaCell, the greater the percentage of overall removal,
a phenomenon characteristic of anaerobic processes in general.
     BOD loading rates for the facultative AquaCell have been recorded
as high as 2068 kg/ha/day  (1,843 Ibs/acre/day) with secondary treat-
ment levels still  being attained.  This performance is due to the high
bio-film surface area which accelerates both sedimentation of particu-
 late BOD and aerobic metabolism of dissolved BOD material.
                                      389

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                                       Table 1


                   Treatment Performance of Primary (anaerobic)  and

                          Secondary (facultative)  AquaCells,

                            Without Use of Aquatic Plants

                             (Nov., 1978 - August, 1979)
PARAMETER
BOO (mg/L)
S.S. (mg/L)
COD (mg/L)
Turbidity
(NTU)
TOC (mg/L)
pH (average
means)
Ammonia *
(mg/L)
RAM
SEWAGE
INFLUENT
218.4
247.9
518.0
205.0
277.6
7,4
40.9
PRIMARY
ANAEROBIC
AQUACELL
EFFLUENT(a)
109.0
27.9
142.0
103.4
67.5
6.9
34.0
* REMOVAL
ANAEROBIC
AOUACELL
50.0%
88.75
72. 6%
49. 6%
75. IX

16.9*
SECONDARY
FACULTATIVE
AQUACELL
EFFLUENT
15.7
11.9
61.0
34.2
32.7
7.3
28.9
TOTAL %
REMOVAL
ANAEROBIC AND
FACULTATIVE
AQUACELLS (b)
92.82
95.2%
88.2%
83.3%
88.0%

29.3%
  * The secondary  or facultative  AquaCell,  in  this case, is not  intended to achieve
    complete nitrification.   In situations where an advanced secondary level of
    treatment with complete  nitrification is required,  increased aeration rates
    and slightly increased retention  time will provide  this level of treatment,

(a) 14 hr.  retention time (6  hr.  Stage 1; 8 hr. Stage 2).

(b) 2 day retention time  (combined).
                                         390

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                                         FIG. 3
            COMBINED TREATMENT PERFORMANCE OF  PRIMARY  (ANAEROBIC)
                       AND  SECONDARY  (FACULTATIVE) AQUACELLS
  250-
  200-
<
ce.
   100
o
o
    50



    40



    30



    20




    10



    0
                           Anaerobic AauaCell

                           Effluent
«—  Anaerobic-Facultative

    AquaCell  Effluent
                                                                 EPA Secondary

                                                                 Discharge Standards

                                                                 (SOD i S.S.  only)
                    HR.
                                DAY
                                                      . Javs
      Raw 5ewaqe

      Influent
                                     RETENTION TIME
                                              391

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CO
CO
               300
            o
z  200
uu
            y  100
            z
            O
            <->   80
                60

                40


                20


                 0
                                                                    FIG. 4

                                   BIOCHEMICAL OXYGEN DEMAND REMOVAL BY  PRIMARY & SECONDARY  AQUACELLS
                                                                             Raw Influent

                                                                             Anaerobic  Effluent (14 hr.  retention)

                                                                             Anaerobic-Facultative Effluent
                                                                                                (2 day retention)
               EPA Secondary
            Discharge Standards
                   O
Iliv.      Dec.
    iy/8
                                    Jan.
                                Feb.
                                                     Mar.
Apr.     May
    1979
                                                                    June
July
Aug.

-------
CO
co
CO
                     300
                  X
                  I-
                  z
                  o
                     ZOO
                  <
                  LU
                  o

                  <
                  in
                  o
                  o
                  o
mo


 CO


 60


 40


 20


 0
                                                                            FIG.  5


                                           SUSPENDED  SOLIDS  REMOVAL BY PRIMARY &  SECONDARY AQUACELLS
                        Raw Influent

                        Anaerobic Effluent (14 hr.  retention)


                        Anaerobic-Facultative Effluent (2  day retention)
                                                           EPA Secondary

                                                        Discharge  Standards
                        Nov.     Dec.

                            1978
                                          Jan.
                                                  Feb.
                                                            Mar.
                                               Apr.     May

                                                   1979
June
July     Aug.

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Sludge Stabilization and Reduction

     The first stage of the anaerobic AquaCell achieved a sludge re-
duction rate of 85-90% for the ten-month period during which the
sludge was retained in the system.  These high reduction rates are
due  to (1) mixing, high substrate contact, and constant reinnoculation
by the incoming wastewater as it flows upward through the sludge layer,
and  (2) the long solids retention times made possible in a cost-
effective manner by this type of construction and design, in contrast
to conventional primary sedimentation and sludge digestion technology.
These high solids reduction rates are within the range of 84% reduction
reported by Coulter, et al. (21) for their pilot scale upflow digester.
No occurrance of scum buildup has been experienced during the ten-month
period.  Samples of sludge removed by a diaphragm pump from Stage 1
showed easy pumping and flow characteristics and excellent dewatering
capabilities.  Samples placed on single media sand drying beds were
completely dewatered within one week.  The pumped sludge also had
little odor.  Simpson (22) and Pretorius (23) also reported very good
dewatering properties for sludge removal from their upflow anaerobic
digesters.  Analysis of four aliquots of sludge taken at different
times showed an average moisture content of 91%.  Ash content was 53%.
Nutrient content was low, representative values being 0.90% nitrogen,
0.39% phosphorus, and 0.04% potassium, due to the long retention periods,
Very little solids accumulation was evident in Stage 2 of the anaerobic
AquaCell, with less than 0.02cu. meter after ten months.

Advanced Treatment

     The final two cells of the Cardiff facility (Cells 4 and 5 -
Figure 2) are designed to achieve various levels of advanced tertiary
treatment.  Both cells contain floating water hyacinths and duckweeds
for removal and recapture of nutrients for recycling purposes, and for
shading out of suspended algae.  Several forms of BioWeb substrate are
used to greatly increase bacterial activity, particularly with regard
to nitrogen removal.  BOD, suspended solids and nitrogen levels de-
cline in direct relation to the retention time of the water.  With
water hyacinths as the major plant component, BOD and suspended solids
levels below 5 ppm can be achieved within 5 days retention time.  Use
of duckweeds in place of hyacinths resulted in slightly decreased
treatment efficiencies,  indicating an additional 20 to 30% increase in
retention time might be required to achieve the same treatment objec-
tive.
     The percentage of total nitrogen removed by the aquatic plants is
relatively small in comparison to that by other elements of the AquaCell
system.  Results indicate that a year-round average total of 182 grams
of nitrogen was removed per day by Cells 4 and 5.  Yet, of this total,
only 18 g/day of nitrogen (10%) could be attributed to the biomass of
the aquatic plants, with 90% being removed by the BioWeb food chain
organisms and benthic denitrification processes (see also ref.  18).
     Phosphate removal rates have been relatively low, ranging from 1
to 2 ppm during the 4.5 day retention period.  This is as expected
since the phosphorous demand of aquatic plants, bacteria and inverte-
brates is only one-fourteenth to one-twentieth that of nitrogen.
                              394

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               Table 2
Coliform Removal By Primary, Secondary
        and Tertiary AquaCells
Treatment Stage (Effluent)
Raw Wastewater
Primary (Anaerobic) AquaCell
Secondary (Facultative) AquaCell
Tertiary (Aerobic) AquaCells
Sand Filter
MPN/100 ml
Mean Values
50,200,000
1,946,667
623,000
17,666
5,633
%
Removal
(Cumulative)
i
96.1 %
98.6 %
99.96%
99.99%
                        395

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      For  situations  where higher phosphorus removal is required,  other
methods such as  land application or chemical precipitation can be
integrated with  the  AquaCell system (11).
      Reduction of  total  coliforms occurred  rapidly (Table  2),  with  an
average 96%  reduction occurring  in the  anaerobic AquaCell  alone.
Initial data on viruses indicates removal  rates  as  high as  100%.   Re-
sults of  these studies and studies now  being completed on  heavy metal
and  chlorinated  hydrocarbon removal rates will  be  published  in a  later
paper.  Further  information on results  from the Cardiff AquaCell  facility
can  be obtained  from references  11 and  20.

SOLAR AQUACELL SYSTEM DESCRIPTION AND DESIGN RATIONAL

      The  Solar AquaCell  system is made  up of a  series  of aquaculture
derived unit processes modified  for greater process  control  and for
advanced  treatment capability.   The specific combination of  AquaCell
types to  achieve an  overall treatment process is adaptable to  site-
specific  requirements, effluent  quality requirements,  and  water or
by-product reuse desires.   All AquaCells  are based  on  modified lagoon
construction techniques  as  described in the preceeding section, and
incorporate  high surface area BioWeb substrates of various configurations
to optimize  conditions for  the biotic components of  the system and
reduce land  area requirements.   The following sections will  discuss
further the  design rational and  physical  characteristics of  the unit
AquaCell  systems, their  application to  various  climatic and  effluent
requirements  and engineering criteria necessary for  preliminary evalua-
tion.

Anaerobic AquaCell System  (Primary Treatment)

      The Anaerobic AquaCell  (ANA) was recently  developed by  Solar Aqua-
Systems specifically for low operation  and  energy costs while  still
achieving reliable primary  or secondary treatment of wastewater.  Pre-
treatment of raw sewage using a relatively  simple, low  cost  technique
is useful in aquaculture processes as a means of buffering shock loads
and reducing solids  to the  following lagoons.  Anaerobic processes are
routinely  used for  the reduction and stabilization of  sludge, to a
lesser extent for the treatment of high BOD, industrial, and agricultural
wastes, and in a lagoon configuration,   for  preliminary  treatment of
domestic wastes.   The potential advantages  of anaerobic treatment are
many and include (24,25):
     1. Low Energy Requirements
     Anaerobic processes  do not require aeration and thus have signifi-
cantly reduced energy requirements compared to aerobic processes.
     2. Capability of Producing Energy
     One of the end products of anaerobic fermentation is methane gas.
Under proper conditions this gas  can be utilized for heating and/or
production of electricity.  McCarty  (26) has estimated that anaerobic
digestion of municipal sludge and solid wastes and agricultural wastes
could yield about 20% of  the current natural gas consumption in the
United States.
     3. Excellent Solids  Reduction and  Stabilization
     The potential of anaerobic processes for solids reduction and
                              396

-------
stabilization is well recognized as evidenced by the common use of
this methodology for sludge management.   In addition, anaerobic
digestion of sludge induces an alteration of the water binding charac-
teristics which permits rapid and economic sludge dewatering.
     4. High Loading Rates and Low Microbial Growth
     High loading rate capabilities of anaerobic processes and conse-
quent ability to handle shock loads make them ideal for preliminary
treatment of wastewaters.   The low microbial growth rates eliminate
the need for supplemental nutrients with nutritionally unbalanced wastes.
     Despite these potential advantages, anaerobic treatment processes,
as currently used, have been troublesome, which has tended to limit
wider application.  Two main problems have existed with conventional
methods, odors and process instability.
     In the case of open anaerobic lagoons, lack of capability for pro-
cess control, and the lack of covers to seal in odors has limited their
use.  High rate anaerobic sludge digesters also emit odors when they
malfunction or leak gas.  The problem is with the basic design.
     High rate biological systems are inherently unstable and require
close operator attention and control in order to obtain and maintain
proper performance.  This is primarily due to the slow growth rates,
fastidious anaerobic requirements and sensitivity to environmental
change of the methanogenic portion of the anaerobic microbial popula-
tion.   In anaerobic processes, two principle populations of microor-
ganisms are recognized, the acidic and the methanogenic bacteria.  The
acidic bacteria are responsible for initial breakdown of the raw influent
organics into smaller molecules, mainly volatile acids.  These acidic
bacteria are hardier and more resistant to environmental fluctuations
and  influent  toxins than the methanogenic bacteria.  In addition, since
they have growth  rates approximately  20 times that  of  the methanosenic
forms,  the acidic bacteria are also capable of more  rapid recovery after
upset  and/or  increased activity in response to variable influent  loading
rates.  The methanogenic bacteria convert  the breakdown products  of  the
acidophiles into  CC>2 and methane gas.  They are  the  more vulnerable  of
the  two populations  to influent fluctuations and the slowest  to recover
from upset.   Conventional anaerobic systems are  generally designed as
mixed  processes  in which  these  two populations of bacteria  are cultured
simultaneously  in the  same volume.  This  strategy attempts  to maintain
the  proper balance  and ratio between  the  two, with  emphasis primarily
on the metahnogenic bacteria.  However,  close monitoring and  control
of pH,  temperature,  and loading rates are necessary to prevent upset
(usually defined as  cessation  of methane  production) and  emission of
odors.
      The  Solar  AquaSystems  Anaerobic  AquaCell  is a  slow  rate  anaerobic
process  designed to  take  advantage  of the volume dilution  and relatively
inexpensive construction  and  operation  costs  of  lagoon processes.  The
use of high surface area  fixed films  provides  the  important advantage  of
maintaining a stable environment  for  the  anaerobic  microorganisms.   The
ANA is designed for preliminary treatment of  incoming  raw wastewaters
 in order to reduce the loading rates  and  load  fluctuations  on the facul-
 tative and  aerobic AquaCell lagoons,  reduce energy  requirements  for
 preliminary treatment and for  the following aerated treatment stages,
 provide long-term digestion and storage of accumulating  sludge,  and  re-
 duce overall operator attention and maintenance requirements  for  the
                                      397

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entire wastewater  treatment system.   It is designed as a  two-cell
system to separate  the acidic and methanogenic microbial  populations,
and optimize conditions for each of  these phases of anaerobic  treatment.
It is analogous in  concept to the dual cell systems of Coulter, et. al.
(21), Pretorious (23), Pohland and Ghosh (27), and Massey and  Pohland
(28).
     The first cell of the anaerobic  AquaCell is an upflow sludge con-
tact chamber similar  to those designed and tested by Black (29),
Stander, et. al. (30), Simpson (22) and Lattinga (31) and sometimes
referred to as the  anaerobic activated sludge process (32).  This
cell contains primarily the hardy acidic bacteria which use the sludge
as an attachment substrate.  Hydraulic retention times are calculated to
permit this portion of the microbial  population sufficient time to
perform initial breakdown of the incoming waste organics.  In  addition,
this first stage acts as a sedimentation basin and the sludge  layer acts
as a physical filter for suspended solids, grease, and heavy metal
entrapment.  Due to the mixing and heat (in winter) provided by the
incoming wastewater, sludge stabilization and reduction rates  are
extremely high, while at the same time the use of low cost lagoon
construction allows sufficient volume to obtain long solids retention
times.
     Reaction with sulfides in the sludge layer encourages the formation
of insoluable and non-toxic metal-sulfide complexes, thus de-toxifying
and removing a high proportion of incoming heavy metals from the efflu-
ent of the cell (33-34).  This process is significant in  that:  1)
removal of the heavy metals increases the safety for water reuse options
such as irrigation, groundwater recharge, etc., and 2) the methanogenic
bacteria in cell 2  are protected from heavy metal toxicity,  improving
process stability.
     The operation of the 2nd cell of the anaerobic AquaCell is similar
in principle to the anaerobic filters of Young and McCarty (35) , McKim,
et. al.  (36), and Genung,  et. al. (37).  However, unlike the above
authors single cell digesters,  the 2nd cell of the SAS Anaerobic AquaCell
is a horizontal flow reactor designed primarily to culture methanogenic
bacteria.   It is the main site of BOD reduction and methane production.
The methanogenic bacteria are provided with a high surface area of
fixed biofilm in the form of vertically oriented BioWeb  substrates.   In
addition to providing a stable attachment site for minimizing washout
of the methanogenic bacteria,  the BioWeb substrates also accelerate
suspended solids removal from the process stream.  The vertical orienta-
tion of the webbing allows "self-cleaning" and deposition of  the coagu-
lated suspended solids to the cell bottom where solids reduction and
stabilization occurs.   Because of the vertical orientation and the high void
volume of the BioWeb substrates,  the system cannot be subject to blockage
as is the case with vertical flow packed-bed reactors.   In addition, the
use of lagoon construction techniques with horizontal flow in this cell
permits retention volume increases economically to compensate for reduced
winter operating temperatures,  exceptionally high loading rates,  or
variable nutrient inputs.   Retention times for the anaerobic  AquaCell
can vary between 12 hours  to 4 days or more,  depending on effluent
desired.   Our experience with the anaerobic process and  results from the
literature (37),  indicate  that use of extended retention times (i.e.
3-4 days)  could achieve secondary quality effluent,  although  this has not:
                              398

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yet been tested.  The anaerobic cell currently at  the SAS Cardiff  labora-
tory has a total retention time of only 14 hours.
     Control of odors from the Anaerobic AquaCell  is achieved by use
of a floating hypalon cover, tightly sealed along  the edges of  the
lagoon.  No odor problems have been encountered during  the ten months
operation of the anaerobic AquaCell.
     Methane production has not consistently been monitored at the
Cardiff facility.  However, based on kinetic rates of methane production
versus COD removal, reliable estimates can be provided  for cost analysis
for use in heating and/or electrical production.  For example, assuming
an average influent COD of 500 mg/L, a 70% reduction in COD by the anaer-
obic  AquaCell  and  65% CH^  composition  of  the  released gas, methane pro-
duction will average approximately  84.5 m3/day  at  a  3785 m3/day (1 mgd)
flow  rate.
     A criticism of anaerobic systems is the necessity  of maintaining
elevated temperatures for maximum process efficiency.   However, this
criticism stems mainly from experience with high rate anaerobic sludge
digestion systems which function in the mesophilic range of 30° to 37°C.
As Loehr (24) points out, "It does not follow that anaerobic treatment
must  occur at optimum mesophilic temperatures.  Satisfactory anaerobic
treatment can occur if an adequate mass of active microorganisms and a
sufficiently long  solids retention time are provided for the system".
Furthermore, studies by Pfeffer (38) show that the relative drop in
metabolic rate  is  less for anaerobic systems than  for aerobic systems.
Additional information on the effect of reduced temperatures on anaer-
obic  wastewater treatment processes comes from successful experience for
many  years with anaerobic lagoons in Alaska (39) and in Canada  (40).
In addition, Genung, et. al. (37), working with an anaerobic fixed film
bioreactor similar in operational principle to Stage 2  of the SAS
Anaerobic AquaCell, states that temperature changes in  the range of
10° to 25° C did not significantly effect removal  rates.  Coulter  et.al.
(21)  found only a  15% reduction in BOD removal between  winter (4°C)
and summer (22°C)  conditions in their pilot investigations of an anaer-
obic  contact process.  The SAS Anaerobic AquaCell  has been operated with
influent temperatures ranging from 18°C to 31°C with no apparent change
in removal efficiency.  For cold climate locations, an  increase in reten-
tion  time fron  0.5 up to 1-2 days should prove adequate to maintain
"advanced" primary treatment.  Snow, ice or ice loads on the floating
cover present  no problem, and in fact add to  insulation to reduce  heat
loss.
      Sludge handling with  conventional primary sedimentation and secondary
treatment processes is a critical and  costly  problem  (41), since there
is little in situ  solids reduction and/or stabilization in most of these
systems.  In addition to increased capital, energy and  maintenance costs,
conventional digestion systems require close  operator attention and  con-
 trol  for proper functioning, and thus  are not cost effective for
 aquaculture  systems.
      The design of the SAS Anaerobic AquaCell provides  simplified  and
 superior solids reduction  due  to long, in situ, sludge  retention  times
which eliminate daily handling problems and reduce  final volumes.
Representative daily dry solids accumulation  rates for  six conventional
wastewater  treatment processes  (42) and the SAS Anaerobic AquaCell are
 given in Table 3.  An 85%  reduction rate  for  a  six month sludge retention
                                      399

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                                                                            TABLE  3
                                        COMPARISON OF  SOLIDS  PRODUCTION  BY  THE  ANAEROBIC  AQUACELL  WITH CONVENTIONAL  METHODS
•C*
o
o
PROCESS
NUMBER
1
2
3
4
5



6

7
TYPE
OF
PROCESS
SAS Anaerobic AquaCell
Septic Tank'2'
Imhoff Tank'2'
Primary Sedimentation
Primary Sedimentation
& Trickling Filter
With Secondary Sedi-
mentation (2)
Primary Sedimentation
& Activated Sludge I2'
Activated Sludge'2'3'
(Package Plant)
TREATMENT LEVEL
Primary

Yes
Yes
Yes
Yes
Yes



Yes

Yes
Secondary

(5)
No
No
No
Yes



Yes

Yes
SEPARATE
PROCESS RE-
QUIRED FOR
SLUDGE
DIGESTION?
No
No
No
Yes
Yes



Yes

No
FREQUENCY
OF
SOLIDS
REMOVAL
Once per 6-12 Months
Once per 1-2 Years
Once per 20-60 Days
Daily
Daily



Daily

Daily
DRY SOLIDS
PER DAY
0 FLOW BATE OF
3785 m3/DAY
(1 MGD),OR(4)
10,000 PEOPLE* '
170 kg (375 Ib)
367.4 kg (810 Ib)
313 kg (690 Ib)
340.2 kg (750 Ib)
558 kg (1230 Ib)



635 kg (1400 Ib)

1020.6 kg
(2250 Ib)
                            (1) Assuming water usage of 378.5 I/person/day (100 gpd) and 300 mg/1 or 0.25 Ibs/person/day of S.S.
                                   in wastewater.

                            (2) Data  from:  Water Pollution Control  Federation.  1977.  MOP/8 - Wastewater Treatment Plant Design
                                   Washington, D.C.  560 pp.

                            (3) Raw wastewater discharged directly to aeration  tanks.
                            i'l) To determine dry solids production for other  treatment  capacities,  multiply or divide by proportional
                                   factor based either on flow rate or number of people served.

                            {'-,) Our results  to date  indicate that longer retention times in the anaerobic AquaCell  should produce
                                Si.-ti)nddry effluent levels.   We are  now beginning  tests  to  determine this.

-------
time was used to calculate dry solids production for the SAS Anaerobic
AquaCell, which, according to our data, is somewhat conservative.  As
can be seen from Table 6, there is 50% less sludge to handle with the
AquaCell system as compared to conventional primary sedimentation
(primary treatment with separate sludge digestion facilities) 69% less
than a trickling filter plant (secondary treatment) and 73% less than
an activated sludge plant (secondary treatment).  At influent suspended
solids concentrations averaging 300mg/L sludge  pumping  &  disposal will be
required only once per year from the anaerobic AquaCell.  In aquaculture
treatment systems using macrophyte plants such as water hyacinths, the
digested sludge can be mixed with harvested plants to make a more at-
tractive compost.

Facultative AquaCell (Secondary and Advanced Secondary Advanced  Treatment)

      Facultative lagoons are in world-wide use for wastewater
stabilization due to their relative simplicity and ability to handle
wide variations in organic loading.  The SAS Facultative AquaCell
operates at a higher rate than conventional facultative  lagoons  in
order to reduce land area requirements anywhere from one tenth to
one fiftieth of conventional lagoons.  This size reductionand higher
loading  rate capability are made possible by the high  surface area
BioWeb substrates and efficient diffused aeration  systemwhich also
contribute to increase process stability.  The facultative AquaCell
design maintains anaerobic conditions  in the lower portions  of the cell
to reduce energy requirements and provide for anaerobic  digestion and
stabilization of precipitated suspended solids.
     Retention  times of  the Facultative AquaCell can vary between 0.5
to 1.5 days, depending on effluent quality requirements  and  local
climactic conditions.  It is normally  recommended  that an anaerobic
AquaCell be placed in series before the facultative AquaCell to  reduce
and stabilize organic loading and consequent aeration  requirements.
In this  two-stage configuration, a total retention time  of only
2-3 days are required to reliably achieve advanced secondary quality
effluent (BOD,  T.S.S. less than 10 mg/L).  One  to  two  days are required
to achieve standard  secondary quality  effluent  levels  (BOD,  T.S.S.
less  than 30 mg/L).  Complete nitrification, if required, can also
be accomplished in the facultative AquaCell with an increase in  applied
aeration and/or retention  time.
      The Facultative AquaCell, as described above, does not require
aquatic  plants  to achieve a  secondary  or advanced  secondary  treatment
level.   Increased suspended  solids from growth  of  planktonic algae
have not been a problem with the SAS Facultative AquaCell due to the
relatively short retention periods  (0.5 - 1.5  days).   In addition,
no greenhouse cover  is required, even  in areas with severe winters,
provided retention time  is sufficient  to compensate for  reduced  meta-
bolic  rates  at  reduced  temperatures.   In cases where removal and reuse
of nutrients  is desired,  floating aquatic plants can be  grown and
harvested  from  the facultative  AquaCell.  In  tropical  areas, hyacinths
and/or  duckweeds can be  grown year-round without greenhouse  covers.   In
 the  United  States, a greenhouse covering would  be  required  for most
areas  if hyacinths are  to  be used on  a year-round  basis. Alternatively
hyacinths  can be grown  during warm  periods and  duckweeds during  the
                                      401

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winter, since certain species of duckweeds are very cold tolerant.
In areas with severe winters, the use of a greenhouse cover will improve
winter performance, permit a decrease in required retention times, and
allow growth of aquatic plants on a year-round basis.  These design
options must be considered on a case by case basis.
     With primary  treatment, sludge buildup in the facultative AquaCell
has averaged approximately 8 to 10 mm per year.  Thus, there should be
no requirement for sludge removal from the cell for fifty to sixty.
years of operation.  There is also no need for a final clarifer and/or
recirculation requirements.

Aerobic AquaCells - Advanced (Tertiary) Treatment

     Advanced or tertiary wastewater treatment using the Solar AquaCell
System is achieved by passing the secondarily treated effluent of the
anaerobic - facultative AquaCells through an additional aerobic AquaCell
or Cells.  The aerobic AquaCell contains floating aquatic macrophytes
(water hyacinths and/or duckweeds) to further reduce BOD, suspended
solids, and nitrogen to meet advanced treatment effluent levels.
     Treatment rate in the aerobic AquaCell is a linear function of
retention time and temperature.  As previously stated, the biological
film of microorganisms on the BioWeb substrates are responsible for the
major portion of treatment, with the aquatic plant components account-
ing for only 10-20% of the total nutrient removal (11,18).  Packing
densities for the BioWeb can vary from 46,500 m3 (500,000 ft2) to
186,000 m3 (2,000,000 ft2) of active surface area per 0.4 ha (1 acre)
(equivalent to 0.19 m2 (2 ft2)  to 0.56 m2 (6 ft2) per 3.785 L (1 gal)
per day , depending on treatment objectives and cost benefit analysis.
Since this represents two to six times greater active surface area than
conventional bio-film processes (trickling filter or bio-disc), it
allows use of conservative design practices and increases the shock
loading capacity of the AquaCell system.
     The use of a greenhouse for covering the tertiary cells is dependent
on local climatic conditions and the type of macrophyte plant cover
selected.  In tropical areas,  no greenhouse cover is required for heat
retention or to allow growth of hyacinths and duckweeds on a year-round
basis.  In areas with an abundance of water fowl, e.g. near migratory
routes or winter  feeding grounds, the duckweed will have to be protected
with a light, low cost bird netting over the ponds.   In areas with arid
climates and consequent high evaporation rates, increases in total dis-
solved solids could become a problem and require use of a single layer
tensile greenhouse covering.   In cooler zones, the use of a greenhouse
cover is dependent on the type of aquatic plant cover used.   Duckweed,
being more cold tolerant than hyacinths,  can be cultured on a year-
round basis in the southern and southwestern portions of the U.S.  without
greenhouse cover.   However, hyacinths will require a  greenhouse cover
almost anywhere in the U.S. if  reliable winter treatment objectives are
to be met.  An option, as described for the facultative AquaCell,  is to
utilize hyacinths during spring,  summer and fall and duckweeds during
the winter periods, though use  of duckweeds year-round allows simpler
harvesting procedures and equipment.   In  northern areas of  the U.S.  'i.e.
generally above 38°N subject to regional  differences especially in the
central and eastern states),  a  greenhouse cover is a requirement for
                              402

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year-round tertiary treatment operation with any species of plants.
     As previously mentioned, phosphorus removal in the AquaCell system
is relatively slow, estimated at 0.5 - 1 ppm per day retention time.
Where complete phosphorus removal is required, either an increase in
retention time or lime precipitation can be utilized.  With lime precipi-
tation, only about 30% of normal liming quantities is required due to
the tertiary AquaCell removal of interferring organic substances (BOD,
S.S., and ammonia) from the effluent.
     Duckweeds are harvested from the AquaCell system by means of a
continuous in line effluent skimming device adjustable to draw off either
surface or subsurface effluent.  Separation of duckweeds from the efflu-
ent works effectively by use of static screening, after which the duck-
weed can be conveyed or pumped as a slurry to the reuse area.  Duckweeds
make an excellent food supplement for fish, chickens, pigs, or cattle,
due to their high protein content.  Alternatively, they can be composted
with sludge removed from Stage I of the Anaerobic AquaCell for soil
application, or digested for methane production.  Hyacinths can be re-
moved periodically from the aerobic AquaCell by means of an in-pond
pusher boat and a bank mounted chopper/conveyor.  The hyacinth slurry
is then pumped to the reuse area.  A unit developed by Solar AquaSystems
requires use of only one man for operation.  The hyacinths can be com-
posted to produce a high quality soil amendment, which, in addition  to
increasing nutrient content of  the soil also increases moisture retention,
due to its fiberous nature.  Alternatively, the chopped hyacinths can
be used for methane production or as an animal food supplement.
     Retention times for an Anaerobic-Facultative-Aerobic AquaCell system
designed to provide advanced tertiary treatment will vary with climate
and effluent options.  For example,  to achieve an advanced tertiary
treatment effluent suitable for many industrial or recreational needs,
approximately 5-6 days total retention are required.  To produce water
of drinking water quality, retention times of 8-12 days are required to
ensure complete safety.  In colder climates, retention times will in-
crease dependent on ambient operating temperatures experienced at the
particular site.  Use of the double  layer  tensile structure greenhouse
allows year-round operation with reduced retention times in these
situations.

Land Area Requirements

     For primary  treatment, in regions where water supplies are not  a
problem, and which lie next  to deep  oceanic areas suitable for discharge
of primary  treated wastewater, advanced primary  treated effluent with
ocean  discharge may be the most cost effective  treatment alternative.
In these cases, use of the Anaerobic AquaCell can provide  an advanced
primary  treated effluent with  minimum operation  and maintenance costs.
Land requirements would be 0.1 ha  (0.25 acres)  to 0.2 ha (0.5 acres) of
water  surface area per 3785 itr/day  (1 mgd) for  this  level  of  treatment,
depending  on climatic zone and treatment level  desired.  There  are  no
land requirements  for separate sludge digestion facilities or processes
associated with  sludge digestors.   Since solids  reduction  in  the  Anaero-
bic  AquaCell is approximately  50%  greater  than  for conventional primary
 treatment  facilities  (table  3),  land area  requirements  for drying beds
 are  also reduced.
                                      403

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      Secondary  treatment by means of  the Anaerobic-Facultative AquaCell
 combination would require 0.4 ha  (1 acre)  to 0.7 ha  (1.5 acres) of
 lagoon  surface  per 3785 m^/day  (1 mgd) depending on  climatic conditions
 and  effluent qualities  (secondary or  advanced secondary) required.  Since
 there is no requirement for separate  sludge digestion facilities, final
 clarifiers and  a 69 to  73% reduction  in sludge drying bed requirements
 as compared to  conventional activated sludge and trickling filter
 processes (Table 3), the total  land area requirements for an AquaCell
 secondary or advanced secondary effluent process are actually smaller
 than that required for  conventional processes.  In addition to reduced
 land area requirements, the AquaCell  process provides a greater biologi-
 cally active surface area for treatment, higher dilution factors, a
 simplified process train and significantly lower energy requirements
 than conventional alternatives.
      For advanced treatment, a  Solar  AquaCell system consisting of the
 Anaerobic-Facultative-Aerobic AquaCells in series will require 1.6 ha
 (4 acres) to 2.4 ha (6 acres) of lagoon surface per  3785 m^/day (1 mgd)
 depending on effluent quality requirements and local climate.  Additional
 land for composting of harvested macrophytes, sludge drying and control
 building represents the only other land area requirements.

 Energy  Requirements

      Operation  of the Anaerobic AquaCell for primary treatment of waste-
 waters  can be viewed as an energy producing process  if the methane gas
 produced by the process is utilized,  either for heating purposes or to
 drive an electrical generator.  The process itself requires no energy
 input.  The only other energy costs (aside from influent and effluent
 pumping if required)  are for comminutation, intermittant sludge pumping
 and  disinfection.
     For secondary treatment levels (Anaerobic-Facultative AquaCell),
 energy  requirements for aeration of the facultative AquaCell would vary
 from 6 kW/h to  7.5 kW/h per 3785 m^/day (1 mgd) for secondary to advanced
 secondary treatment,  with an increase to 15 kW/h per 3785 m^/day (1 mgd)
 for  complete nitrification.   Comminutation, intermittant sludge pumping
 from the first stage of the anaerobic AquaCell and disinfection represent
 the only other  energy requirements of the system. If the methane gas from
 the anaerobic AquaCell is utilized,  a large proportion of the energy
 requirements could be met from  this source.
     Energy requirements for advanced (tertiary)  treatment (Anaerobic-
 Facultative-Aerobic AquaCells) range  from 18.6 kW/h to 22.4 kW/h per
 3785 ra^/day ( 1 mgd).   Other process  energy requirements which include
 harvesting of the aquatic plants, solar heat transfer spraying,  inter-
mittant sludge  removal from the first stage anaerobic AquaCell and dis-
 infection are all minor when compared to the continuous energy require-
 ments for aeration.  Again,  a proportion  of this total energy require-
 ment could be met by utilization of methane gas produced by the naaerobic
 AquaCell.

 Other Operation and Maintenance Costs

     Operation and maintenance of the AquaCell process is exremely low
 compared to conventional processes.   These savings are a result of trie
                              404

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following characteristics of the AquaCell system:
     1.  In situ sludge digestion - There are no requirements for
external sludge digestion facilities or chemical costs.  Intermittant
sludge pumping direct to the drying beds or liquid tank transport are
the only 0 & M requirements for sludge management.
     2.  No recirculation process, clarifiers, or other process units
required.  The main mechanical components of the AquaCell system are the
blowers, comminutor, disinfection and harvesting equipment, if aquatic
macrophytes are used, all of which are low maintenance items.  There
are also few process pipes subject to potential clogging and/or breaking.
     3.  Reduced disinfection costs - Due to the high removal rate of
coliforms, disinfection requirements are significantly reduced, saving
on both capital costs, costs of chemicals and operator attention
requirements.
     Operator skill and attention requirements for the primary and
secondary treatment processes (Anaerobic and Facultative AquaCells) are
minimal.  The process can go for long periods with only periodic checks.
Approximately 0.5 operators per 3785 m^/day (1 mgd) is estimated for
secondary treatment.  The main operator requirements for tertiary treatment
are harvesting and composting, which are performed on a weekly to monthly
basis depending on the season.  Operator requirements for tertiary treat-
ment is approximately 1-1.5 operators per 3785 m^/day (1 mgd).  Because
of the relative simplicity of the process, operator training requirements
are also minimal.

Capital Costs

     Capital costs for a complete secondary treatment AquaCell process
(Anaerobic and Facultative AquaCells) should range between  $1.00 to  2.00
per 3.785 L  (1 gal) of treatment capacity, depending on local codes,
labor and equipment costs, use of a greenhouse cover and effluent  quality
requirements.  Capital costs of an advanced (tertiary) treatment AquaCell
facility  (Anaerobic-Facultative-Aerobic AquaCells) should range between
$2.50  to  $4.00 per 3.8 L (1 gal) of treatment capacity, depending  on
effluent  quality desired, location and size of the process,  labor  costs,
etc.   Since  the AquaCell system is an innovative  treatment  process,
it qualifies for 85% federal assistance.  Because of the low 0 & M of
the AquaCell process overall life cylce  costs will be substantially below
conventional processes.  A community can easily recover the 15% share
of capital costs on savings in operation and maintenance costs as  com-
pared  to  conventional processes.


SOLAR  AQUACELL AWT SYSTEM FOR THE CITY OF HERCULES

     The  City of Hercules is a small but rapidly  growing planned commun-
ity 48 km (30 miles) northeast of San Francisco which is presently com-
pleting construction of  an innovative Solar AquaCell wastewater treatment
system.   Startup of  the  first phase, designed  to  treat 1,325 m3/day
 (350,000 gpd) of raw wastewater to advanced tertiary quality is scheduled
for late January,  1980.  The  final phase will  treat 7,570 m^/day (2 mgd.
 to advanced  tertiary quality.  This system can produce a range of
 effluent quality for multiple reuse options,  as well as recycling  100%
                                      405

-------
of  the harvested aquatic plants,  solids and digested  sludge  into reusable
by-products within  the  community.  A  detailed  discription  of  this  facility
has been previously published  (44), so only a  summary is presented below.

Facility Design

     The Hercules facility  is  designed as a three-phase system consisting
of  an anaerobic AquaCell, followed by a facultative AquaCell  and a larger,
third phase aerobic AquaCell containing water  hyacinths and duckweeds
(Figure 6).  In the ultimate facility (7570 m3/d or 2 mgd),  three  inde-
pendent facultative/aerobic AquaCell  units  will be operated  in parallel
to  permit  the City  flexibility to select and more efficiently  meet  chang-
ing water  discharge or  reuse needs.   For the first phase,  scheduled for
startup in January, 1980, only about  one-half  of Solar AquaCell "A" is
being constructed.
     Pretreatment will  consist only of grinding  (comminutor).  The two
stage anaerobic AquaCells are  designed to provide 12-20 hour  total re-
tention time.  The  second AquaCell (facultative) and  the third AquaCell
(aerobic with aquatic plants)  in each series are combined  in  the same
earthen pond, with  a rubber curtain wall hydraulically separating and
providing  a channel for the facultative treatment area.  The  facultative
cell will  not contain water hyacinths or duckweeds in order to maximize
oxygen exchange through the surface.
     In the aerobic (tertiary) AquaCell stage, oxygen levels  will range
from 2 ppm at the influent  to  6 ppm or greater at the effluent end.
Water hyacinths and duckweeds  will be cultured over the entire water
surface of this stage in order to prevent growth of algae, to assist
the BioWeb reduction of BOD, SS, total dissolved nitrogen  and phosphates,
and to produce a valuable by-product.  Multiple overflow screens will
reduce escape of detritivore invertebrates,  fish or plants.
     The only posttreatment process required for secondary quality efflu-
ent will be disinfection.  Ozone was selected over chlorine,  in spite of
its slightly increased costs,  for several reasons.  Dechlorination would
be necessary for bay discharge, thus increasing total costs of chlorine
usage.  For reuse needs, chlorine is less desirable since  it  is known
to increase levels  of potentially toxic chlorinated hydrocarbons, and
does not provide the additional oxidation and back-up  treatment capability
of ozone.  For tertiary effluent needs,  sand filtration before ozone
treatment will assure removal  of any remaining suspended solids.

Advantages of the Solar AquaCell System to the Community

     With  the ultimate 7570 nr*/d (2 mgd)  facility, the three  separate
Solar AquaCell lagoons (Figure 6)  will be operated in parallel to allow
the City flexibility to select for and more  efficiently meet changing
water reuse and/or discharge criteria.  By varying the wastewater flow
to each of the three AquaCells, retention times can be proportionallv
increased  to produce a secondary quality effluent for irrigation  or bay
discharge.   For example, if a market exists  for 3785 m-5/d (1 mga)  of
high quality water  (e.g. BOD, TSS  less than  3.0 ppm;   total nitrogen less
than 5.0 ppm;  ammonia less than 0.1 ppm),  than 50% of the 7570 ~\~>. d (2
mgd) flow  can be diverted through  2 of the 3 lagoons at an average
retention  of 10 days,  while the remaining 3785 m^/d (1 mgd) is rrriatsd
                              406

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                                             FIGURE 6
                PROPOSED 2.0  MGD SOLAR AQUACELL FACILITY  - CITY  OF HERCULES
                   FACULTATIVE CELL
                   SOLAR  AQUACELL C

                   (AEROBIC, 2 ACRES)
         ANAEROBIC
                       /"ANAEROBIC  POND"
                         (floating cover)
                                    ing
I                   |||  sand filter,
• aquatic plant
I recycling area
|(compost & Bio-gas)
LJ^eftt^t
                                                            FACULTATIVE CELL
                                                          SOLAR AQUACELL B

                                                          (AEROBIC,  2  ACRES)
                                                               SOLAR AQUACELL A

                                                                (AEROBIC,  2  ACRES)
hi
ozone,  pump
station,  & oper-  |
ations  blrlg.
area
                                                                FACULTATIVE CELL
                                                                        '
                                                    Current Phase  1  lagoon under
                                                    construction.
Plan View of the proposed 2.0 MGD Solar ArjuaCell lagoon Treatment Facility for the City of Hercules,
lalifornia.   Each AquaCell will be 2.0 acres (6 acres total).  The 0.35 MGD treatment phase currently
under construction consists of a 1.5  acre AquaCell system with anaerobic, facultative and aerobic stages,
approximately '5 of  AquaCell A.

-------
to secondary quality in the third lagoon with a retention time of two
to three days.
     Cost analysis indicated that a 7570 m^/d (2 mgd) AquaCell system
designed to produce an advanced tertiary quality water could be con-
structed for about the same cost (3.5 million - 1977 dollars) as a
7570 wr/d (2 mgd) expansion of the existing activated sludge facility
at neighboring Pinole.  In addition to producing only secondary quality
effluent with limited reuse options and value, the Pinole alternative
would have required much greater pumping distances.  The high construc-
tion, maintenance and operation costs of conventional, high technology
AWT facilities, compared to the Solar AquaCell process ruled the former
out of consideration by the City.
     The low energy requirements of the Solar AquaCell process, and
greatly reduced maintenance, sludge handling and labor expenses should
reduce annual 0 & M costs to about 50% less than projected 20 year costs
for the alternative activated sludge system, even though a much higher
quality water will be produced.  This cost savings differential is
expected to increase as energy costs continue to escalate.  Personnel
needs will be limited primarily to harvesting and composting activities,
requiring only one to two full-time operators per 7570 m^/d (2 mgd).
     The aquatic plants harvested on a regular basis can be reused by
conversion to either methane gas, high quality organic compost, or sold
as an animal feed supplement.    Hercules preferred reuse of the plants
in the form of compost, needed in large quantities for landscaping
purposes during development of their community over the next 20 years.
An additional advantage with composting is derived by composting the
digested sludge removed periodically from the first stage anaerobic
AquaCell with the harvested plants.   By composting both forms of waste-
water solids together for recycling, the sludge takes on a more attrac-
tive marketing form and in-turn further enriches the nutrient value of
the plant compost.  In this manner,  100% of all solids can be recycled
directly within a community instead of paying for hauling to out-of-town
dump sites,  as is currently done with most neighboring conventional
treatment plants.  Total solids handling volumes will also be reduced
compared to alternative treatment methods.  Further, the relative simpli-
city and stability of the composting and anaerobic AquaCell digestion
processes, in comparison to conventional primary treatment and high rate
anaerobic digestion methods, greatly reduces operator skill requirements,
odors and process failures common with conventional solids handling
methods.
     The Solar AquaCell Treatment Facility has been designed by Solar
AquaSysterns, Inc., Encinitas,  California.  KCA Engineers, Inc., San
Francisco, provided engineering on basic treatment facility components.
The City of Hercules was recently honored with the State of California's
Governor's award for the most appropriate technology project of the year.
     The AquaCell system is a proprietary and patented system of Solar
AquaSystems, Inc.  Further information or che process can be obtained
by writing Solar AquaSystems,  Inc.,  P.O.  3ox 88,  Encinitas, CA. 9202-i
or calling (714) 753-0649.
                              408

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                               REFERENCES
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2.  Anonymous.  1978.  Political Technical Mire Breeds Poor Sewage
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3.  Hegg, B.A., K.L. Rakness and J.R. Schultz.  1978.  Evaluation
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4.  Asuno, T. and K.L. Wasserman.  1979.  Water Reclamation Plants
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5.  Anonymous.  November, 1977.  Advanced Sewage Treatment Plants,
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6.  Feliciano,  D.V.  1979.  AST & AWT:  Fitting Treatment to Needs.
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7.  Henderson,  U.B. and F.S. Wert.   1976.  Economic Assessment  of
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8.  Duffer, W.R. and J.E. Moyer.  1978.  Municipal Wastewater Aqua-
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9.  Wolverton,  B.D.   (ed.) 1978.  Compiled Data on the Vascular Aquatic
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10.  Dinges,  R.   1978.  Upgrading  Stabilization Pond  Effluent by Water
    Hyacinth Culture.  Journal W.P.C.F.   50:833-845.

11.   Serfling, S.A.  and C. Alsten.   1979.  An Integrated,  Controlled
     Environment Aquaculture  Lagoon  Process  for Secondary or Advanced
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     600/9-79-011.   U.S.  Environmental  Protection  Agency,  Cincinnati,
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12.   Bunch,  R.L.  1979.   Introduction and Objectives  of Symposium.
     pp 2-3.   In E.J.  Middlebrooks.  at  al.  (eds)  Performance and
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13.   Hillman, W.S.  and D.D.  Culley,   Jr.   1978.  The  Uses  of  Duckweed.
     American Scientist.   66:442-451.
                                     409

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14.  Harvey, R.M, and J.L. Fox.  1973.  Nutrient Removal Using
     Lemna minor.  Journal W.P.C.F.  45:1927-1938.

15.  Lecuyer, R.P. and J.H. Martin.  1975.  An Economic Assessment of
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16.  Metcalf and Eddy, Inc.  1979.  Wastewater Engineering:   Treatment,
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17.  Keveren, R.I.  1973.  Plastics in Horticultural Structures.
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18.  Serfling, S.A.  1976.  Recycling of Nitrogenous Wastes  and the
     Role of Detritus in a Closed-Cycle Polyculture Ecosystem.

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     #14-34-001-7817.

20.  Stewart, W.C., C.R. Alsten, S.A. Serfling and D. Mendola.  1979.
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     Water Reuse - From Research to Application.   AWWA Research Founda-
     tion, Denver, Colorado.  781 pp.

21.  Coulter, J.B., S. Soneda, and M.B. Ettinger.  1957.  Anaerobic
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22.  Simpson, D.E.  1971.  Investigations on a Pilot-Plant Contact
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23.  Pretorius, W.A.  1971.  Anaerobic Digestion of Raw Sewage.  Water
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24.  Loehr, R.C.  1971.  Anaerobic Treatments of Wastes.  In Develop-
     ments in Industrial Microbiology.  Vol. 9.  pp 160-174.

25.  McCarty, P.L.  1964.  Anaerobic Waste Treatment Fundamentals.
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26.  McCarty, P.L.  1973.  Methane Fermentation - Future Promise  or
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     University of Massachusetts, Amherst.
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27.   Pohland,  F.G.  and S.  Ghosh.   1971.   Developments  in Anaerobic
     Stabilization of  Organic Wastes - Two-Phase Concept.  Environ.
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28.   Massey, M.L.  and  F.G. Pohland.   1978.   Phase Separation of
     Anaerobic Stabilization by Kinetic Controls.  Journal W.P.C.F.
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29.   Black, M.G.  1974.  Operational Experiences with  an Abattoir
     Waste Digestion Plant at Leeds.  Water Pollution  Control.
     73:532-537.

30.   Stander,  G.J.,  G.C. Gillie, W.R. Ross  and R.D. Baillie.  1967.
     Treatment of Wine Distillery Wastes by Anaerobic  Digestion.   In
     Proceedings of the 22nd Industrial Waste Conference, Purdue
     University.

31.   Lettinga, G.  1979.  Direct Anaerobic  Treatment Handles Wastes
     Effectively.  Industrial Wastes.  25:18-41.

32.   Kirsch, E.J. and R.M. Sykes.  1971.  Progress in  Industrial
     Microbiology.  9:155-237.

33.   DeWalle,  F.B., E.S.K. Chian and J. Brush.  1979.   Heavy Metal
     Removal with a Completely Mixed Anaerobic Filter.  Journal W.P.C.F,
     51:22-36.

34.   Gould, M.S. and E.J. Genetelli.  1975.  Heavy Metal Distribution
     in Anaerobically Digested Sludges.  Proceedings of  the 30th
     Industrial Waste Conference, Purdue University,  pp 689-697.

35.  Young, J.C. and P.L. McCarty.   1967.  Anaerobic Filter for Waste
     Treatment.  Eng. Bull. Purdue University Eng. Ext.  Ser.  129:559-
     574.

36.  McKim, M.P., A.A.  Cocci, T. Virarghavan and R.C.  Landine.  1979.
     Combined Aerobic-Anaerobic Treatment Produces Low  Cost, Quality
     Effluent.  Industrial Wastes.   25:53-55.

37.  Genung, R.K., D.L. Million, C.W. Harcher and W.W.  Pitt, Jr.  1978.
     Pilot  Plant Demonstration of an Anaerobic Fixed-Film Bioreactor
     for Wastewater Treatment.  Paper presented  at the  Symposium on
     Biotechnology in  Energy  Production  and Conservation, Gattinburg,
     Tenn.  May 10-12,  1978.

38.  Pfeffer, J.T.  1970.  Anaerobic Lagoons - Theoretical  Considera-
     tions,   pp 310-320.   In  2nd  International Symposium for Waste
     Treatment  Lagoons, Kansas  City, Missouri.   June  23-25, 1970.

39.  Clark, S.E., H.J.  Coutts and R. Jackson.   1970.  Alaska Sewage
     Lagoons.   pp  221—231.   In  2nd  International Symposium  for Waste
     Treatment  Lagoons, Kansas  City, Missouri.   June  23-25, 1970.
                                      411

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40.  Dornbush, J.N., 1970.  State-of-the-Art - Anaerobic Lagoons,
     pp. 382-387.  In 2nd International Symposium for Waste Treatment
     Lagoons, Kansas City, Missouri.  June 23-25, 1970.

41.  Vesilind, P.A., 1979.  Treatment and Disposal of Wastewater
     Sludges.  Ann Arbor Science.  Ann Arbor, Mich.,  323 pp.

42.  Water Pollution Control Federation & American Society of  Civil
     Engineers, 1977.  MOP/8 - Wastewater Treatment Plant Design.
     Water Pollution Control Federation,  Washington,  D.C. & American
     Society of Civil Engineers, N.Y. 560 pp.

43.  2nd International Symposium for Wastewater Treatment Lagoons.,  1970
     Kansas City, Missouri, 404 pp.

44.  Serfling, S.A. & D. Mendola, 1979.  The Solar AquaCell AWT  Lagoon
     System for the City of Hercules, California.  pp 671-680.   In Pro-
     ceedings - Vol. 1, Water Reuse - From Research to Application.
     A.W.W.A. Research Foundation,  Denver, Colorado.  781 pp.
                              412

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Economics, Energy, and By-Product
Utilization Session

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                                  Session IV




          ECONOMICS, ENERGY, AND BY-PRODUCT UTILIZATION




                        3ohn Colt and Maurice Bender






       Rising  energy  costs  will  have a  significant  impact  on the selection of




treatment processes in the 1980's.  Conventional advanced \vaste\vater  treatment




systems  and  some  forms  of secondary treatment  may  become  prohibitively




expensive.   Treatment  systems using  aquatic  plants  and  animals  represent  a




low-cost,  low-energy alternate rnetnod of treating wastewater, and at the same




time  allow  for the recovery  of  energy and  nutrients.




       The energy  consumption  for  wastewater treatment in the United States




(1979) is  about 0.1.5 quads  (or  0.15  x 1015 BTLI/year).  This represents about




0.2 percent of  the nation's  energy  usage.  By  1990,  it is projected that  tins




energy usage  will douole to  about 0.26  quads.




       While these numbers are small relative to the national energy consumption.




they  are  significant on  a local level.   The energy consumption  by municipal




treatment plants  may  represent 1/3  to 1/4 of the energy purchased by many




local governments.




       Aquatic treatment systems  are  land-intensive,  using  5  to  40 acres per




Mgal/d (million gallons/day).  These  systems use much less  energy  and resources




than  conventional  systems (such as  activated  sludge), and  therefore, increases




in  energy costs  will have less  impact  on the economics of aquatic treatment




systems.  Also, the salvage value of the land  may represent a significant monetary




return.




       The  cost  of a 1  Mgal/d water hyacinth system  for advanced secondary




treatment (BOD and Suspended  Solids j£  10  rng/L) ranged from  35  to  57  percent




of conventional treatment.  The use of aquatic systems with  land treatment and




oxidation ponds  are  cost-effective for advanced  wastewater  treatment.
                                          415

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      Aquatic  treatment systems may also  allow  significant resource recovery.




Aquatic plants may be used for soil conditioners, paper, or cattle feed.  Harvesting




and  processing  costs  as well as the value  of  the final product  are  not well




defined  at this  time.  Public health aspects of pathogen transmission  or  heavy




metal and  trace organic concentration may restrict the use of these items for




animal or  human consumption.




      The most economic energy  recovery system for  small  communities may




be low-temperature gasification (pyrolysis) rather than anaerobic digestion.  The




seasonality  of  aquatic   plant  production  may  require  special  management




techniques, greenhouse cover, or additional  storage  during the summer.   By year




2000, wastewater aquaculture may supply a net energy contribution  of  between




0.01 and 0.05 x 10    BTU/year or 0.01 to  0.05 percent of our energy consumption.




      Even though the  economics of aquatic systems appear  highly favorable,




implementation of this technology may be delayed  by legal and political factors.




Legal problem areas may be the National Environmental Policy Act (environmental




impact  statement), the  Food and  Drug  Administration (if  any of the   products




are  consumed  by  humans or animals),  and water  rights law,  especially  in the




western United States.  Legal  and political  conflicts  can be dealt with by the




establishment of a lead agency  to  coordinate  planning,  public information, and




legal requirements.  Citizen  participation at all stages  may help  address many




of the social and political problems.  Public acceptance of innovative technology




may be greater than that of the regulatory agencies.
                                 416

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                 ENERGY CONSUMPTION,  CONSERVATION AND  RECOVERY
               IN MUNICIPAL WASTEWATER TREATMENT - AN  OVERVIEW*
                               Maurice F.  Bender
                          Argonne National  Laboratory
                               Argonne,  Illinois  60439
                                   Abstract
          The potentials for energy consumption,  conservation and recovery
     at municipal wastewater treatment plants are relatively small compared
     to the national energy figures.  Nevertheless they are significant,
     particularly to local owners and operators.   Estimates of energy con-
     sumption, as well as opportunities for conservation and energy recovery
     in municipal wastewater treatment operations, are reviewed.   The relation-
     ship between energy conservation and aquaculture based wastewater treat-
     ment systems is also introduced.  Finally, current Department of Energy
     activities in this area are presented.


     When we speak of energy consumption in wastewater treatment in relation to
the natural energy consumption figures, we speak of relatively small numbers.
Although there is considerable variability in the figures currently available,
a commonly accepted range of values is that municipal wastewater treatment
accounts for about 0.1 to 0.3 percent of the nation's energy usage.  This
amounted to about 0.15 quads or 0.15 x 1015 Btu's in 1978.  We also anticipate
that, except for unforseen major breakthroughs in energy conservation and
recovery technology by 1990, we can expect this energy usage to roughly double
to about 0.26 quads.  Again, there  is some difference of opinion on this
estimate.  The doubling can be attributed to an increased volume of wastewater
and to the higher degree of treatment required to meet more stringent Federal
and state limitations.  The relationship comes about because it becomes increas-
ingly difficult to remove wastewater constituents as the degree of treatment
required increases.  Traditionally, the more sophisticated the removal process,
the more energy required to extract a given mass of pollutant from the waste
stream.  Advanced treatment processes, for example, often require large quan-
tities of chemicals that require energy intensive methods of production.

     Although the numbers are relatively small on a national usage scale,  they
are significant, particularly on a  local level.  The cost of supplying energy
to a typical wastewater treatment  plant generally represents between 20 and  40%
of the overall operating budget.   In general,  the energy consumption by munic-
ipal treatment plants  represents an estimated  one quarter to one-third of  the
                                           417

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energy purchased by many local governments.  Depending upon the scenarios
employed we are speaking of an increased cost of approximately one-half to
one billion dollars to municipal governments through the year 1990.   Conse-
quently, there is or should be strong motivation for support, at the local
level, to meet the goals for energy conservation in wastewater treatment.
Professionals will have to become increasingly better informed of energy
considerations in the planning, design, construction, operation and  mainte-
nance of wastewater treatment plants.  The Department of Energy and  the
Environmental Protection Agency have embarked on such efforts and I  will speak
further on this subject a bit later.

     Energy considerations are closely related to a number of design factors
employed in the planning and designing of an overall wastewater treatment
process.  The actual energy consumption by a given plant is a function of such
variables as the location of the plant, the treatment processes employed, the
age of the plant and the effluent limitations that have to be met.   The cost
of the energy, calculated over the lifetime of the plant, must be coupled with
these considerations.

     One of the greatest opportunities for energy conservation in wastewater
treatment plants lies with the energy currently consumed by prime movers such
as pumps and blowers.  Based upon reviews of detailed energy audits  of specific
plants, such as the energy audit for the West Southwest Plant of the Metro-
politan Sanitary District of Greater Chicago, it becomes apparent that 90% or
more of the energy consumed at most plants can be attributed to prime movers.
At the West Southwest Plant the total energy consumption in 1976 was about
2.5 billion kilowatt hours (kWh) of which 2.2 kWh were attributed to prime
movers.  A notable fact is that due to the large amounts of energy consumed
in pumping air into an activated sludge system, this type of treatment is one
of the most energy-intensive processes employed in wastewater treatment.

     The optimization of the pumping operations to reduce energy consumption,
therefore, should be a focal point for energy reduction.  There are  three
general areas for optimizing the energy efficiency in pumping operations.  They
are:  1) the selection of the approproate pumps for a given job, 2)  optimizing
overall system performance, and 3) the proper operation and maintenance of the
pumps.  It should be noted that this major consumptive use of energy in most
plants is also inherently a problem in aquaculture wastewater systems, and
optimization of pumps selection, operation and maintenance should be considered
in these systems as well.

     There are a number of opportunities for increased energy conservation and
recovery which I want to touch upon.  (John Beneman, one of the speakers in our
session, will speak further on the subject of energy recovery.)  These oppor-
tunities include the following:

     • improved dewatering methods in the context of an optimum sludge
       management strategy,

     • increased utilization of sludge digestion gas,

     • use of chemicals or other materials which require less energy in
       their production than are currently employed,
                                    418

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     •  more energy efficient design  of treatment  plant  buildings,

     •  the use of small  turbine-generators  at  the outfalls  from waste-
       water treatment plants,

     •  combined sludge and solid waste energy  recovery  systems.

     These are just a few of the areas where we can develop more energy efficient
and generally more cost effective systems while meeting  water quality requirements.

     I  will now spend a few minutes  discussing DOE's activities and plans  in
this area.  In particular, I will talk about the Urban  Waste and Municipal
Systems Branch in the Office of Conservation.   Don Walter is the Branch Chief.

     DOE has recently completed a draft program plan for energy conservation
and recovery in wastewater treatment plants.  Although  I believe it will require
considerable reworking, it is extremely gratifying to some  of us who have  nur-
tured such an effort.  The plan is directed towards stimulating the development
and commercialization of technologies to reduce the energy  requirements and to
increase the efficiency of wastewater and water treatment processes.  For  the
near term, it places a strong emphasis upon retrofitting existing plants.   The
emphasis is upon working closely with the EPA, and Department of the Interior,
and other agencies, in complimenting their objectives,  as well as working  towards
DOE's objectives.

     Although DOE's current state of activities with regard to energy in waste-
water treatment can be summarized as being in a planning stage, there are  several
additional efforts which have some relevance here, three of which I would  like
to mention:  1) along with EPA, DOE is funding the development of a manual  for
energy conservation and recovery in municipal  wastewater treatment plants.   It
will be published as part of the EPA Technology Transfer series, 2) DOE is
participating in the Reedy-Creek Project, which was previously discussed in
this conference, 3) the DOE is sponsoring a conference on the subject of Energy
Optimization of Water and Wastewater Management to be held in New Orleans  on
December 10-13.  Announcements on the table in the back of the room describe
the conference further.

     Finally, I would like to address the question:  Where does wastewater aqua-
culture lie in DOE's current plans?  Frankly, the answer is that it is  not
currently  a part of the plans.  This does not imply that DOE  is not interested
but I believe a stronger arguement has to be made concerning  the energy conser-
vation and recovery opportunities which can arise from the use of wastewater
aquaculture systems.   I am convinced that there are such opportunities.  Some-
time back, while providing technical consulting support to DOE, I worked towards
achieving  DOE participation  in  the Reedy Creek (Disney World, Florida)  aqua-
culture effort.   I  felt that there was sufficient energy conservation  potential
in  such systems to  warrant DOE  getting its  feet wet and yet not getting bogged
down.   I  also believe we now need to quantify the energy conservation  and recov-
ery in wastewater  aquaculture units as a basis for comparison with  conventional
processing units.   Implicitly,  the use of aquaculture processing units  should
result  in  the use  of  less energy than conventional treatment, assuming  effluent
limitations can  be  met.  We  know that about 80% of the sewage districts in  the
                                          419

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U.S.  have treatment facilities with capacities of one million gallons per day
or less (this capacity serves about 10,000 municipal  residents).   Because of
economy-of-scale principles, aquaculture-based treatment systems  may become
attractive for some of these smaller plants, particularly in light of the sched-
ule for treatment requirements.   The potential energy conservation and by-product
utilization characteristics of aquaculture-based wastewater treatment may further
the acceptance of such systems as alternative technologies.

Thank you.
                                    420

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     RESOURCE RECOVERY FROM WASTEWATER AQUACULTURE

     Larry 0. Bagnall, Associate Professor of Agricultural Engineering,
       Institute of Food and Agricultural Sciences,  University of
       Florida,  Gainesville, Florida  32611
ABSTRACT

     Removal and recycling of the nutrients and other components in
the wastewater aquaculture system are completed by harvesting,  pro-
cessing and utilizing the aquatic organisms in which the nutrients are
collected.  Aquatic species grown in wastewater have been experimen-
tally used for food, feed, fiber, fertilizer and energy.  Some of the
processes and products appear to be technologically and economically
feasible on an operational scale.

INTRODUCTION

     Agriculture has traditionally taken the elements of soil, water,
air, nutrients, sunlight and selected organisms and used them to
produce food, feed, fiber and energy.  Aquaculture, by extension,
takes the same elements, usually excepting soil, and produces similar
products.  The technology of agriculture, developed over millenia in
diverse environments, has established preferred species, cultural
practices, harvesting and processing procedures, storage and marketing
structures.  With  the possible exception of fisheries, aquaculture has
established none of these.

     In the context of this  conference, the principal product of the
wastewater aquaculture is pure water.  The disposition of what was
referred  to in one of the preliminary program drafts as "by-products"
is  an annoying, but secondary, problem.  Properly managed, they could
conceivably be resources of  as much economic importance as the water.

     In agriculture and ordinary aquaculture, an important objective
is  to maximize production of a usable or salable biological product,
given available resources.   Species and varieties are selected  and
bred on the basis  of utility and productivity.  The most productive
aquatic species are usually  considered to  be weeds because of  their
great productivity and lack  of apparent utility.  "A weed," according
                                       421

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to Emerson, "Is a plant whose virtues have not been discovered."  The
virtue that has been discovered, and is the basis of this conference,
is the ability of these species to rapidly absorb and immobilize vast
quantities of pollutants.  Another virtue is the concentration of
energy and nutrients, which only is realized by the application of the
developing techniques of management, harvesting and processing.

Aquatic Plant Aquaculture

     Plants are the primary producers in all agricultural and aquacul-
tural systems.  They combine the raw nutritional elements with the energy
of the sun into chemical and physical structures usable by "higher" spe-
cies.  Subsequent use and passage of the elements and energy up the pro-
cessing and consumption chain always results in some loss of matter and
energy, though sometimes with some enhancement in the quality of the
residue.

     The ideal plant for wastewater aquaculture with resource recovery
rapidly produces high areal dry matter density, is insusceptible to
chemical, disease, cold or insect damage, and is readily and cheaply
harvested and processed into a readily accepted product.  And doesn't
exist.  There are some species, however, that have enough of these
virtures to make the other characteristics worth tolerating or improving.

     Some species of plants can be harvested by appropriately selected
herbivores, such as fish.  If a marketable species of fish is used, it
can be harvested directly.  If not, carnivorous species can prey on
the herbivores in a managed system and the carnivores can be harvested.
Each succeeding step in the food chain introduces some loss of nutrient
harvest, but the economic return of the higher quality of harvested
nutrients may offset this.

     The cultural system must be designed to accomodate the harvesting
system if resource recovery is to be economically feasible.  Though the
harvesting requirements for different species vary, such considerations
as channel width, water depth, run length, freedom from obstructions,
beam width and bearm height may be important.  Space and facilities
for onsite processing and utilization may have to be provided.

     Systematic and efficient direct harvest of the plants and asso-
ciated organisms has the greatest potential for maximizing recovery of
resources.  Direct harvest can be manual or mechanical, depending on
the size of the cultural system and the level of local technology.
Harvesting is simply removing the plant from the water and may include
cutting in the case of matted or rooted macrophytes, elevation of all
macrophytes, and concentration of all species.  Though it is usual to
harvest small quantities of the crop at frequent intervals, complete
removal and re-seeding may be practiced in some cases.  The harvesting
rate and frequency may be established before the harvesting system is
designed.
                                     422

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W
AQUATIC ^
PLANTS '
HARVEST
.


pDOf^ITCC -t-
i
                                                          PRODUCT

-------
     Harvested aquatic plants are too wet, too large or too small,  and
too biologically or chemically unstable to be conveniently and economi-
cally handled, stored, and utilized.  Large plants may be chopped and
small plants aggregated to reduce their intractibility.  Water, and hence
mass, may be reduced by drying, pressing or centrifuging.  Additional
processing may be applied to convert the plants to a form acceptable to
the proposed utilization.

Water Hyacinth Harvesting - Processing - Utilization

     Much of the wastewater plant aquaculture reported at this confer-
ence has involved water hyacinth (Eichhornia crassipes (Mart.) Solms).
Most of my research on harvesting,  processing and utilization of
aquatic plants has involved water hyacinth grown on municipal or
animal wastewater or from natural sites.  Consequently, most of this
paper will be the systems, components and products related to water
hyacinth.

     Water hyacinth most effectively meets the proposed productivity
criterion of the ideal wastewater aquaculture species.  It is also
relatively insect and disease resistant, outgrowing its parasites,  but
is not very cold or chemical resistant.  (A problem relative to its
use in wastewater aquaculture may arise from indiscriminate intro-
duction of more virulent biological control agents, which may require
eradication of all natural stands within some radius of a cultured
crop to prevent a destructive epidemic.)  It is also large, very wet,
bulky, intractible and has virtually no direct utility.

     A network of possible water hyacinth processes and products is
shown in Figure 1.  Harvesting and chopping are precursors to all of
the other processes and all of the products.  Chopping is helpful but
not required for the soil amendment products.  The chopped plants may
be applied directly to land, composted to stabilize and reduce mass,
digested to produce methane, pulped to produce paper, or pressed to
reduce moisture content and produce a highly reactive protein-mineral-
sugar juice.  The juice may be separated to recover a high quality
feed-food protein-mineral concentrate or digested to produce methane.
The pressed fibers may be ensiled with appropriate additives or dried
to produce a granular feed component.

Harvesting

     Water hyacinth stands are typically 100 to 200 T/A of plants 18
to 42 inches tall.  The plants may be relatively detached or tightly
matted.  Containment or restraining devices are needed to force the
detached plants into a harvesting mechanism and vertical cutters may
be needed to separate manageable lots of matted plants for orderly
harvesting.  Water hyacinth is most easily and effectively harvested
by a conveyor projecting into the water below the root level.  Usually
flat wire steel conveying belt is used, but other types, including  chain
and flight have been applied successfully.  In stationary designs a
                                    424

-------
                   PAPER
METHANE
FEED-FOOD
    AG.'JAT'C
    PLANTS
ro
CJl
                                                                                          GRAIN
                                                                           S;LAGE
                                                        DRY FEED

-------
boat is used to push mats of plants to the conveyor and an overhead
reel is used to crowd the plants onto the plants onto the conveyor,
reducing slippage at the turbulent conveyor-water interface.   In
mobile designs, the pusher boat is unnecessary and the reel not as
important, as the motion of the harvester, particularly into a packed
mat, provides the crowding and feeding actions.  Conveyor speed is
typically 50 to 100 ft./min. and conveyor width is 4 to 40 feet.
Estimated energy cost for this type of harvester is 0.3 HP hr/T and
estimated economic cost is $0.12/1.

     A new drag conveyor harvester design is being developed at the
University of Florida which should have a much higher capacity than
existing designs, reducing energy consumption slightly and economic
cost substantially but improving flow over the conveyor-water interface.

     Efforts have been made to harvest water hyacinth by pumping and
have had various degrees of success.  The advantage of this type of
harvester is its simplicity, low initial cost, ease of handling the
harvested product, and expected ease of feeding.  The factors that
have prevented successful application so far have been high energy
requirement, disposition of the harvested plants and bridging of
plants in the entry flow.  It may be necessary to pre-shred plants to
assure reliable feeding.  It will be necessary to substantially reduce
surplus water required to carry the plant fragments (presently 10 Ib.
of water/lb. of wet plant material) to reduce energy requirements and
disposal or recovery costs.

Chopping

     Harvested water hyacinth bulk density is 5 lb/ft3 or less.  The
plants are usually interconnected and en masse are exceedingly difficult
to handle manually or mechanically.  The logical means of improving
density and handling characteristics are to bale or to chop.   Energy
requirement for baling is low, densitites around 50 lb/ft3 can readily
be achieved, and bales can be readily handled mechanically.  However,
wet water hyacinth bales are mechanically unstable and become less
stable with time, decay putrefactively (they stink), and must be
subsequently chopped in almost any resources recovery system for
supply to subsequent processes.

     The plants can be readily chopped with crimpers or agricultural
flail or cylinder-shear bar choppers.  Chopping usually increases bulk
density to 15-20 lb/ft3.  Crimpers accept to full width of the harvested
mat, but must be designed with more clearance than typical agricultural
crimpers to accept the higher volume of plants.  A current design being
developed at the University of Florida uses 12 inch diameter rolls with
six 3 inch high sharpened flights, a loading of 100 Ib-in of roll width
and a peripheral speed of 200 ft/min, twice the conveyor speed or the
harvester to which it is attached.  Crimpers used so far have increased
density to 15 lb/ft3, but have not broken the plants sufficiently to
provide a regular fluid stream.
                              .426

-------
     Fluid choppers have been used by several harvester builders.
One uses a full-width flail above the elevating conveyor,  shredding
the plants before they are tumbled or turned in any direction.   The
other drops the plants onto a narrow cross-conveyor which  carries
them under a narrower flail.  The advantages of the former system
are that the chopper is fed more uniformly,  the plants are chopped
before they have a chance to tangle and entwine, and the benefits  of
lower volume accrue throughout the system;  the advantages  of  the
latter system are that a smaller chopper is  required and less material
passes through the gap between the flail and the conveyor. The
material from either system is not very uniform, which may cause some
difficulty with some subsequent processes,  but is much more fluid  than
that from the crimper.

     Cylinder-shear bar choppers use feed rolls or aprons  to  control
the speed and orientation of the material coming to the  cutting
surface, and consequently produce the finest and most uniform product
of the three types.  However, because of the bulk of water hyacinth
and the flacidity of its roots, commercial agricultural  choppers are
only marginally adequate.  We were able to chop 28 T/hr  in a  16 in
wide by 24 in diameter chopper, with energy requirement  of 0.2 hp  hr/T,
but only by careful alignment of the feed.   A cylinder-shear  bar
chopper specifically for water hyacinth is being developed at the
University of Florida.  It  features greater width, lower  speed and
higher throat opening than  typical agricultural choppers  and uses
feed aprons instead of feed rolls.  Energy requirement is expected to
be the same to slightly lower than found in earlier trials and
capacity and reliability higher.

     Cost of chopping is about $0.06/T, based on costs and capacities
of cylinder-shear bar chopping.  Differences between  the  costs
 (energy and economic) of the  three types of choppers  are  unknown, but
equipment is being assembled  at  the University  of  Florida to determine
these differences.

     In almost all instances  (all  instances  that I can think of), the
harvesting and chopping mechanisms should be  incorporated into  a
single maching.  Capacity will be maximized, machine  size minimized,
reliability improved, and  subsequent  system and component costs
reduced.  Energy cost of combined  harvesting-chopping should be about
0.5 hp  hr/T and economic cost should  be $0.16/T.

Soil Amendment - Compost

      Intact or chopped  water  hyacinth,  fresh or composted, may  be
 applied to  soil  as a source of  fertilizer element  as  a means  of
 improving  soil  structure  and  water balance.   The fresh plants  contain
 about  3 percent  nitrogen,  0.7 percent phosphorous  and 2 percent potassium
 or a  dry basis,  but  the dry matter constitutes only 5 percent  of  the
 fresh mass.   About 1/3  of  the nutrients are leached out in the
                                       427

-------
composting process, but 80 percent of the water is lost as well and
the volume is reduced 90 percent, so the mass and volume concentration
of nutrients is higher.  The water hyacinth fiber has excellent water
retention and will improve the water retention of sandy soils.
Incorporated properly, it will bulk clay soils, improving porosity
and drainage.  The principal limitations to its use as a soil amend-
ment are its occasionally high salt content and its high water
retention, both of which are only serious problems when it is used
at very high rates, such as in potting mixtures.

     Intact or chopped plants compost redily.  Chopped plants decompose
more rapidly and produce a structureless humus within 30-60 days with no
additives or attention.  Intact plants decompose more slowly, with
some parts drying and forming resistant structures which retain their
identity.  Under conditions of great depth or high continuing rainfall,
chopped matter may become anaerobic and require turning or forced
aeration.  Crimping or flail chopping, which produce coarse fragments,
appears to consistently compost better than fine-chopped or intact
plants.

     Several aquatic plant harvesting investigators and operators have
reported that householders and farmers readily accept fresh or com-
posted aquatic plants for potting, flower beds and gardens.  One
entrepenuer in Florida had a market developed for a water hyacinth
compost based potting soil.

Paper - Pulp

     Paper and related products have been made from water hyacinth.
Properties have generally been good for packaging applications.
Potential is reportedly limited by low fiber yield and slow drainage
rate, both of which would render water hyacinth non-competitive with
traditional fiber sources.  Many characteristics, including drainage,
are improved by blending with coarser pulp, such as pine.  Nolan
feels that water hyacinth paper production would be uneconomical in
industrialized countries with high labor costs and capital inputs.

Fuel Production

     Biogas containing 63 percent methane can be readily produced
from water hyacinth and its juice (press liquor).  Wolverton reported
yields of 370 1 of biogas (63 percent methane) per kilogram of
volatile solids from chopped water hyacinth in a batch digester.  A
200 1 continuous digester at the University of Florida is currently
producing 120 I/day of 63 percent methane biogas from 24 kg/day of
water hyacinth juice (2 percent total solids).  Conversion is 500 1
biogas/kg volitile solids.
                              428

-------
Pressing

     Harvested or chopped water hyacinth are 95  percent  water.   By
pressing, 35 to 75 percent of the water can be removed in a  few
seconds.  The amount of solid removed with the water depends on
pre-aeration and press action and usually increases with increasing
water removal.  Static pressing of intact plants can remove  35
percent of the water with almost no solids removal.  Aggressive
screws pressing can remove 75 percent of the water and 30 percent of
the solids.

     Most of our pressing research has involved  continuous flow
screw-presses of moderate capability which remove 50 to  70 percent
of the water and 10 to 25 percent of the solids  in a light weight
screw and cage.  The juice passes out through the screen surrounding
the cage and is collected for additional processing.  The fiber is
fine, friable, handles easily and can be readily dried or ensiled.
Intact plants can be pressed, but press capacity is usually  3 to 4
times as great when operating on chopped plants, due to  their higher
density and greater fluidity.

     Screen pressing requires about 2 hp hr/T of chopped plants and
costs $5.76/T.

Juice Concentration

     The juice from the screw-press contains about 20 percent of the
total solid of the fresh plants.  By analysis it is primarily protein,
salt and sugars.  Up to 80 percent of the total solids and 90 percent
of the crude protein in the juice can be recovered by centrifugation,
fine filtration or 24-hour sedimentation.  The 24-hour sedimentation
is enhanced by the suppression of pK, and consequent acid precipitation
of protein, due to natural fermentation.  The juice sediment can be
quickly  solar dried on a screen.  The supernatant, containing the
sugars,  can be digested to produce methane.  As an alternative  to
nutrient recovery for feed or food, the juice can be digested for
methane  and the spent fluid used  for fertilizer.

Ensiling

     The pressed  fiber can be ensiled by mixing with a fermentable
 (sugar  or  starch) carbohydrate,  such as corn or dried citrus pulp,
and  packing into  a nearly airtight container.  As  an alternative to
pressing,  the average moisture  content has been reduced  by dilution
with dry material, such as straw, paper, or wood fiber,  or by wilting.
In any  case,  an average moisture content between 50 to 85 percent,
wet  basis,  and adequate carbohydrate for rapid  fermentation are
required.

     Animal acceptance of properly ensiled water hyacinth has been
very good  and performance has been satisfactory.
                                      429

-------
u
O
         120-
       °F 80-
          40-
V,
        pH 6-
           -Q-
                              = 6.24+ .0908 t
                            oH=5.12 - .162 t
012  4
   FIGURED   EFFECT OF
                        8
                                   -a
              -oH =6.23 -.016/t
                                   o
                                   24
              HOURS
            IME  ON  HYACINTH  JUICE  pH

-------
     Energy cost of producing silage,  including harvesting,  chopping,
pressing, and silo filling is 2.7 hp hr/T of fresh plants or 68 hp
hr/T of stored dry matter.  Economic cost is $17/T of fed dry matter,
which is competitive with traditional feeds.

Drying

     Pressed or pre-wilted water hyacinth may be dried in any type  of
traditional forage dryer to produce a dried feed component.   Energy
cost of drying in a traditional type of rotary dryer is 960  J/g of  fresh
water hyacinth or 24,000 J/g of dry feed.  Economic cost of  producing
dry feed is $117/T, which is unreasonable.

     As an alternative to traditional drying, solar drying can
eliminate to fuel cost and reduce the cost of production of  dry feed
to $20/T, competitive with existing feed sources.

     Dry feed was not as well accepted as silage, and animals did not
perform as well on it.  Water hyacinth in any form should constitute
no more than about 20-30 percent of an animal diet, due to excess
mineral intake and mineral imbalance suppressing total feed intake.

Systems Costs & Returns

     The cheapest method of disposal is land application, with or
without composting.  As level of processing increases, the value of
product increases, but not always uniformly or at a rate which keeps
up with production costs.  A feed market may be difficult to esta-
blish  and maintain, partly due to cost and  partly due to social-
psychological factors.  Biogas may be an easy market to establish
and maintain.  Energy of  producing dry feed by traditional methods
exceeds  the energy content of the feed.
                                       431

-------
                        •RAFTER
                                              ROOF
                                            SUPPORT
                                             COLUMN
WIND-ASSISTED  SOLAR  DRIER
   SIDE VIEW
   SCALE: 1/16
   LOB UF  AGE  790529
                          432

-------
                          TYPICAL  SOLAR  DRYING CURVE
                          PRESSED WATER  HYACINTH
5-
                               DAYS
                                       433

-------
SOLAR DRYING  PRESSED  WATER  HYACINTH
    FORCED vs  PASSIVE
       f" CJr\ O t U    **B.-™*—_urt-i.i-.i_j..
       PASSIVE -O° ™	
                15° ••-•	
               3O° ••"•	
       434

-------
SOLAR DRYING  PRESSED WATER HYACINTH
   EFFECTS TURNING & HALF-LOADING

            TURN       —		 —
            HALf-' LOAD  —---*	
          DAYS
                     435

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WAIERHYACINTH SOLAR  DRYING  TIME,  DAYS
 CONTROL (5cfm/ft , no cover
     pressed, no shade,
     2.5 Ib/f t , no recirculation}
 VELOCITY,   O dm/ft'
            2.5  cfm/ft
           ia
COVER
 TRE AT W SNT    »NTAC T
 SHAD WG

 LOAD»NG
CHOPPED



125 Ib/ft'

       2
              5 Ib/ft
RECIRCULAT1ON
         PARTIAL (2nd DAY)
VELOCITY(O) j« SHADING
COVER X LOADING (1.2»)
COVER x »EC»RCULATIOM
         PARTIAL C2nd DAY)
                                                        17-1
                            436

-------
MINIMUM AREAS TO  SOLAR  DRY  WATERHYACINTH
    PRODUCTION  FROM  ONE ACRE (4000 Ib/da)
    5 cfrn/ft2
    tNTACT   2.5 Ib/ft
            16OO ft2/da
    CHOPPED. 2.5 Ib/ft
            1600 ft
    PRESSED.
                       16400
            SCO fi2/do
            1.25 Ib/ft
            160O ft2/da
            5 fb/ft
            4OO ft2/dq
430O

     6800
                                437

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CO
oo
            PROCESSING  ENERGY
                J/a  OF DRY FEED
                                                    2400O
                                         \J
                                                       16000
   300—
   200—
    100-
              40



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                                                    EC  HV
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-------
CO
rKUV^t.;^IINO LAJO 1
$/Mg OF DRY FEED
$120-
?100-
$80-
$60-
$40-
26
$20 j|
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SC HV 5C HV
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DRY DRY PELLETS

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    ENERGY  FROM WASTEWATER AQUACULTURE SYSTEMS
    John  R.  Benemann,  Ph.D.     Ecoenergetics,  Inc.
    President                  2038  Pleasants  Valley  Rd.
                               Vacaville,  Calif.  95688
INTRODUCTION

     The utilization of aquatic plants  in wastewater treatment [1]
raises the issue of the most suitable uses for the plant biomass
produced during such processes.  In this presentation the utilization
of wastewater-grown aquatic plants as a feedstock for conversion to
fuels is discussed.
     Fuels from biomass is considered one of the most promising solar
energy options, with wastes and residues alone being able to generate
enough fuel, using near-term collection and conversion technologies,
to meet about 5% of current U.S. energy needs [2].  (Current U.S.
energy use is approximately 80 x 1015 BTU/year.)  The collection and
use of existing "non-commercial" forest resources could probably
double the biomass resource base [3].  The production of fuels from
biomass produced on "energy farms" has a large potential,but the
economic and environmental constraints of such systems may be severe,
such that these are generally considered long-term options of un-
certain impact.  This is particularly true of aquatic biomass energy
systems.  The author has recently reviewed the cultivation of aquatic
plants such as microalgae, water hyacinths, and marsh plants, and
their conversion to fuels [4] and concluded that the only near-term
options for energy from aquatic biomass would involve wastewater
aquaculture systems and, possibly, residues from the production of
higher-value chemicals, animal feeds, or foodstuffs.
      In the specific case of municipal wastewater aquaculture, the
conversion to fuels of the aquatic biomass generated is likely to be
their highest economic use, as utilization as animal feeds will be
restricted in most cases by public health considerations.  This is
probably also true for aquatic foodchains and for use of waste-grown
aquatic plants as  feeds in conventional husbandry.  This does not
imply that public  health problems are necessarily inherent in waste-
water aquaculture.  The traditional experience with sewage-fed  fish
ponds in the Far East and even Europe has not revealed  any major
public  health hazards.  However,  in the context of the  intensive


                                      441

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(rather than extensive) wastewater treatment processes necessary in
the U.S., the potential for contamination by heavy metals and toxic
organics, and more rigorous standards and cultural attitudes prevalent
in this country, it may be expected that the recycling of municipal
wastewater-grown organisms directly into the human food chain will
require a very long period of testing before it finds acceptance.
Such restrictions do not apply to animal or food processing wastes.
Thus, this review will be limited to energy from municipal wastewater
aquaculture.
     Another factor in favor of the use of waste-grown aquatic biomass
as an energy source is the established practice of anaerobic digestion
of sludges in municipal wastewater treatment plants.  The aquatic
biomass may be considered a new type of sludge that could be handled
in a similar way to other sludges.  It should be noted that sludge
handling and disposal is often the single largest expense in a modern
municipal wastewater treatment plant.  Thus, the aquatic biomass
may be a liability rather than an asset.  However, this is not certain
as experience in the handling, digestion, or conversion of aquatic
biomass, and disposal of the residual sludge, is practically non-
existent.  This review must draw on other types of experiences and
be speculative in tone.  It starts with a brief review of aquatic
plants in wastewater treatment to allow a determination of the likely
supply and composition of the aquatic biomass available for energy
conversion processes.
AQUATIC PLANTS IN WASTEWATER TREATMENT

     Three types of aquatic plant systems are most often considered
in wastewater treatment--microalgae, floating plants, and emergent
plants.  The microalgae have the advantage of producing dissolved
oxygen that is readily utilized in meeting BOD5.   Their cultivation
is, however, difficult to control, and they are even more difficult
to harvest.  Floating plants—water hyacinths and duckweeds, prin-
cipally—are much more easily harvested, and their cultivation
presents few known problems.  They can serve in wastewater treatment
in combination with mechanical aeration or microalgae.  Their
principal functions in secondary treatment appear to be in providing
a cheap cover which prevents wind mixing and algal blooms, thus
allowing settling of suspended solids and clarification of effluents.
Water hyacinths may also exhibit significant removal of suspended
solids through absorption-filtration by their roots.  Whether water
hyacinths could remove soluble BOD5 by direct uptake of organics is
uncertain.  The stems of marsh plants provide a large, shaded surface
area below the waterline which may allow microbial colonization and
activity.  Submerged plants are found in many oxidation ponds but
are of uncertain applicability to wastewater aquaculture.
     These aquatic plants have relatively high productivities and
high nutrient content.  The literature data [see Refs. 4 and 5) are
summarized in Tables 1 and 2.  These data are based on a detailed
review of the literature, exemplified by Table 3 which presents
selected references for productivity of water hyacinths.  By multi-
plying productivity with nutrient composition, it is possible to
calculate the removal of nutrients, e.g. tertiary treatment, affected
                              442

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                        TABLE 1
          RANGE OF PREDICTED BIOMASS PRODUCTIVITIES

                     FOR AQUATIC PLANTS
                       (from Ref. 4)
       AnuaHr Plant                    Ran9e °f Productivities
       Aquatic Plant                          MT/HA/yr*
M-  «=,!«=«  Green algae                        40-80
Microalgae      _*  algae                   25.50
Submerged Macrophytes (Hydrilla, etc.)         25-50

                 Water hyacinths              60-120
Floating Plants   Duckweed                      20-40
                 Azolla                        20-50
Emergent P,ants
   *Lower value represents currently expected productivities in
   wastewater treatment ponds; higher value refers to future
   possible yields under favorable conditions.
                                     443

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                    TABLE 2,   COMPOSITION OF AQUATIC PLANTS*
                                    % OF DRY WEIGHT
         PLANT TYPE        NITROGEN             PHOSPHORUS          POTASSIUM     ASH
                        MEAN     (RANGE)       MEAN       (RANGE)       MEAN        MEAN
         MICROALGAE      5,8   (1.2-1,1)      0,7      (0,06-3,0)       1,7        14,2


|        SUBMERGED       2,6   (1,7-1,6)      0,15     (0,03-0,9)       2,2        20,8


         FLOATING        4,0   (1,5-7,0)      0,63     (0,1-1,8)        2,5        14,1


         EMERGENT        1,7   (0,9-2,3)      0,18     (0,09-0,32)      2,1         8,6


         *from Reference (5)

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            TABLE  3.STANDING BIOMASS  AND PRODUCTIVITY  OF EICHORNIA CRASS I RES'
CJl
AUTHOR
PENFOUND
ODUM
RYTHER
YOUNT &
CROSSMAN
BOYD
BOYD
WOLVERTON &
MCDONALD
LOCATION
LOUISIANA
FLORIDA
FLORIDA
FLORIDA
ALABAMA
ALABAMA
MISSISSIPPI
r* r~ » f* /\ * i D A \j n r\ o o
SEASON / 9
g/ro
SUMMER 1478
MAY
YEARLY VARIABLE
YEARLY VARIABLE
AUGUST 2130
SEPTEMBER
APRIL- 1090
JUNE IUyU
"Xt"
12.7-14.6
10.3
24.5
(5.4-52)
5-54
17.7
27.6
87.5
COMMENTS

NATURAL POPULATION
H it
(max. productivi
MANAGED CULTIVAT
FERTILIZED POND
FERTILIZED POND
FERTILIZED POND
2° SEWAGE POND
ty)
ION




       *from References (6-10,  15)

-------
by the growth of the aquatic plants.  This can be quite considerable.
For example, if water hyacinths are assumed to produce 100 dry metric
tons/hectare/year (MT/HA/yr) and contain 3.6% N, then one hectare
would be able to remove all the nitrogen in a flow of 0.25 million
liters per day of a typical wastewater flow (assuming 40 mg/L total
N in sewage).
      Unfortunately, such a calculation ignores the large, roughly
ten-fold seasonal variations in productivities for all aquatic plants.
Thus, maximal productivities for water hyacinths in Florida are almost
50 g/m2/day in summer but drop to 5 g/m2/day in winter (Table 3).  One
reason for this seasonal variation, in the case of water hyacinths,
is their well-known sensitivity to cold.  This may be overcome with
greenhouses.  However, greenhouses would further cut down on the low
winter time insolation.  Thus, greenhouses will help in the over-
wintering of the water hyacinths and in extension of their geographical
range, but they cannot completely overcome the large seasonality in
productivity.  Other aquatic plants exhibit similar seasonal produc-
tivities.
      Several alternatives are possible to overcome the limitations  on
tertiary treatment due to plant seasonality—maximization of nutrient
removal processes not dependent on plant growth, storage of sewage
in winter, operation under yearly and seasonal discharge standards
(rather than the current monthly and weekly standards), or combinations
of the above.  Processes for nutrient removal not involving plant
growth include volatilization of ammonia and nitrification-denitri-
fication, absorption by soil or on plants, and chemical precipitation.
All are known to occur to varying degrees in most wastewater aquaculture
systems and may be increased through various operational strategies.
Another approach is to build up an inventory of nutrient-deficient
plants in late summer or fall which would take up nutrients during
the winter.  Obviously, this would require rather sophisticated control
of operations.  Storage of partially treated effluent in the winter
is another possibly attractive and low-cost alternative.
      The seasonality of plant growth also has a significant effect on
the design and operation of any biomass conversion technology and the
use of the fuel produced.  It is obviously best to maintain as steady  a
production rate as possible.  One method is to "draw down" the standing
aquatic biomass crop in winter and build it up in summer.  This also
fits with the strategy of building up a nutrient-starved biomass in
summer.  This is not feasible with microalgae which have a very small
standing biomass and is probably limited in the case of marsh plants
which exhibit strong seasonality in their pattern of photosynthesis
and relative shoot and rhizome growth.  For water hyacinths, greater
flexibility is possible with plant densities higher than optimal
being allowed to build up in fall to be used up in winter.  The recent
quantitative work by Ryther ejt al_. [8] may allow the estimation of the
optimal strategy.
      The amount of biomass produced by a wastewater aquaculture system
depends not only on the season, the specific plant selected, or the
management strategy, but also on the size of the system per unit flow.
This is, at present, an uncertain quantity for most systems.  Con-
ventional oxidation ponds loaded at 50 kg BOD5/HA/day require 5 HA
per million liters per day of sewage flow (assuming 250 mg/L BOD5)
                              446

-------
(equivalent to about 45 acres  per MGD).   Such systems are, however,
very poor and erratic biomass  producers  and, at  any  rate,  should
not be included in the definition of wastewater  aquaculture  [1].
High-rate oxidation ponds (shallow,  mechanically mixed)  may  be loaded
at a yearly minimum of about 100 kg  BOD5/HA/day  in California, and
algal removal, accomplished by a two-day flocculation-sedimentation
process, appears very promising [11].  During  1978 and  1979  the pro-
duction and harvestability of microalgae grown in two 0.1  hectare
pilot-scale oxidation ponds were determined.   The data  indicated that
high productivities and harvestabilities, achieved by a low-cost
sedimentation process, are  possible  with such  a system [11].  How-
ever, the reliability and effectiveness of such  a process remains to
be demonstrated in field-scale tests.
       Aerated water hyacinth ponds could, in principle, be  quite
small, with size only restricted by the need to provide a settling
basin for suspended solids removal.   Currently,  design criteria are
not well established.  However, Solar Aqua Systems, Inc. has designed
a 0.35 MGD  (1.3 x 106 L/day) plant at Hercules, California,  with a
total pond  size of 1.5 acres (0.68 hectare), giving a size of about
1 hectare per 2 x 106 L/day.  This is about five  times the loading
achievable  in high-rate microalgal ponds under  similar climatic
conditions.  Dinges  suggests a  one-acre water hyacinth pond to
remove  algae from the  effluent  of a  waste  stabilization pond  serving
 3,000 people (0.3 MGD).   This  amounts  to increasing the size  of  a
typical  facultative oxidation pond  by  only 10%.  The size of  marsh
 systems are not well established.   In  all  cases the objective of the
 treatment (e.g.  30/30 or 10/10 BOD5/SS standards, tertiary  treatment,
 polishing, etc.)  will  set the size  of  the system.  (See other papers
 in These Proceedings for detailed  discussions.)
        Table 4 summarizes the key  points brought up in the  development
 of municipal wastewater/aquaculture systems.   It is clear that a
 number of uncertainties exist about the amount  of aquatic plant
 biomass that will be produced by municipal wastewater aquaculture
 systems.  The exact size of the systems is not  yet  determined,
 neither is the yearly variation in  biomass productivity, optimal
 standing biomass, or nutrient contents.  The harvesting of the
 biomass will not be addressed here  except in that it is the major
 problem with microalgal production, but only a  relatively minor one
 with higher aquatic plants.  In the next section the use  of the
 aquatic biomass as an energy source is discussed.


 CONVERSION OF AQUATIC PLANT BIOMASS TO FUELS

        The high moisture, high nutrient, and low lignocellulose
 content of most aquatic plants make them ideal  substrates for anaerobic
 digestion.  As this is already a widely used technology in  municipal
 wastewater treatment, it will be emphasized in  this discussion.  How-
 ever, marsh plants may be dried, either prior or after harvesting, and
 can exhibit high lignin content.  Thus, thermochemical conversions may
 be most applicable but will not be discussed in this review.
        Existing experience with anaerobic digestion of aquatic plants
 is very limited.  Microalgae harvested by sedimentation from a high-
 rate oxidation pond have been recently subjected to anaerobic digestion
                                       447

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                         TABLE 4
    GENERAL CONCLUSIONS ON WASTEWATER AQUACULTURE SYSTEMS

 I.  YEAR-ROUND PERFORMANCE WILL BE VARIABLE, BEING SEASONALLY
    (TEMPERATURE AND LIGHT) DEPENDENT.
 2.  THE PHYSICAL PRESENCE OF THE PLANTS MAY BE AS--OR MORE-
    IMPORTANT THAN THEIR BIOLOGICAL ACTIVITY.
 3.  BACTERIAL ACTION IS A PRIMARY FACTOR IN SUCH SYSTEMS
    (E.G., BOD5 REMOVAL, DENITRIFICATION, ETC.).
 4.  PHYSICOCHEMICAL PROCESSES (SOIL ABSORPTION, PRECIPITATION)
    MAY OFTEN EFFECT MORE NUTRIENT REMOVAL THAN THE PLANTS.
 5.  PLANT BIOMASS PRODUCTION MEANS HARVESTING AND DISPOSAL
    PROBLEMS.
 6.  EVAPORATION AND TRANSPIRATION CAN SIGNIFICANTLY INCREASE
    TDS AND DIMINISH WATER REUSE.
 7.  LONG-TERM RELIABILITY CANNOT BE GAUGED FROM SHORT-TERM
    EXPERIMENTS.  SINKS MAY FILL UP.
 8.  ENGINEERING DESIGN CRITERIA IS LACKING.  EVEN IF AVAILABLE,
    ONE-TO TWO-YEAR PILOT PLANTS ARE REQUIRED.
 9.  LAND AREA REQUIRED IS CRITICAL FACTOR.  POTENTIALLY, SUCH
    SYSTEMS ARE OF LOWER COST AND NET ENERGY CONSUMPTION.
10.  EFFLUENT STANDARDS AND PERMITS MUST REFLECT  CAPABILITIES
    OF TECHNOLOGY (YEARLY AND SEASONALY STANDARDS DESIRABLE).
11.  ESTHETIC AND ECOLOGICAL IMPACTS FAVOR THESE TECHNOLOGIES.
12.  MORE RESEARCH IS REQUIRED.
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in a very lightly loaded reactor (due to the low solids  concentra-
tions, 1 to 2%, of the settled material).   The results  indicated
that the microalgae could be readily digested, producing 400  L  of
digester gas (65% methane) per kg of volatile solids  added (minimum
detention time about 18 days) [12].   However, microalgae harvested
with alum at the City of Sunnyvale have not been successfully digested
due to inhibition by  the  alum   [12].   Prior work by Golueke and
Oswald [13,14] indicated that alum-harvested algae could readily be
digested.  The difference can probably be ascribed to flocculation.
       The production of methane gas from water hyacinths has been
studied by a number of different groups; however, no  detailed data  are
available.  Wolverton elt aJL [15] reported in 1975 on five laboratory
batch experiments in three-liter Erlenmeyer flasks fed with 300 to
878 g of wet weight greenhouse-grown, chopped water hyacinths plus
800 ml of water.  The flasks were seeded with an extract of anaero-
bically decomposed plants and shaken once a day.  Gas production was
followed for up to four months.  Cumulative gas production was
highest--!! ml CHi, per g wet weight (g.w.w.)--at the  lowest loading
(300 g wet weight).  Surprisingly, absorption of 5.4  mg nickel  and
6.87 mg of cadmium on 542.8 g w.w. water hyacinths gave high methane
yields (11.3 ml Ch\/g w.w.) and 91.1% methane in the  gas phase.  This
is an unexplained phenomenon which warrants rechecking.  A. Johnson
reported [16] on experiments in Taiwan during 1976 with anaerobic
digestion of vegetable matter using a two-phase digestion system.
Water hyacinths were digested in two smaller batch digesters; however,
gas production data were not taken.   Lecuyer and Marten [17] presented
an "economic assessment" of a biogas production system based on water
hyacinths, assuming 130 MT/HA/yr of dry weight yield of plant matter
and a 220,000-acre pond system.  Gas production yields were "expected"
to be six scf of methane per dry Ib of water hyacinth; however, no
data were actually collected.
       Chin and Goh report on experiments in Singapore [18] with  12-
liter digesters fed 290 g w.w./L of chopped water hyacinths, corres-
ponding to a 1.8% volatile solids loading.  The digesters were
operated at 37°C and mixed and fed daily for over sixty days with
29 g/L (10-day retention time) and 14.5 g/L  (20-day retention time)
of wet weight hyacinths.  Gas compositions averaged 54% CHu and C02
with steady-state volatile acids at 440 mg/L and 320 mg/L volatile
solids destruction of 56% and 60% and gas yields of 644 ml/g and 673
ml/g for the 10-day and 20-day retention time digesters respectively.
This is the only published data on continuous anaerobic digestion
of these plants.  Loading rates were rather low; however, the con-
clusion may be reached that water hyacinths are a good substrate for
anaerobic fermentations.  This is also concluded from more detailed,
but still unpublished, studies on anaerobic digestion of water
hyacinths carried out by  Klass and coworkers at the Institute of Gas
Technology [19].  They found that sewage-grown plants which have a
higher nutrient content digest better than natural populations.
Results are reportedly comparable to those obtained by anaerobic
digestion of giant kelp [19].  Ryther [10] has also carried out
experiments on anaerobic  digestion of water hyacinths using 0.16 m3
digesters fed three times a week with finely shredded materials, with-
out mixing, at a loading  rate of 0.8-1.0 g/L/day.  Reportedly, the
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Dynatech R & D Corp. and Solar Aqua Systems, Inc.  also have carried
out anaerobic digestion experiments with this plant, but no informa-
tion is yet available.
       This review of the literature reveals that much more informa-
tion should be available by next year, and that, for now, anaerobic
digestion of water hyacinths and microalgae can be assumed to proceed
without significant difficulties and at rates comparable to those
observed with sewage sludge.  Data on anaerobic digestion of other
aquatic plants is very sparse.  Of the submerged plants, El odea was
reported by Koegel et_al_^ [20] to be anaerobically degraded while
Hydrilla has been studied by Dynatech (no data available).  No
references to anaerobic digestion of marsh plants have been found.
It may be expected that the higher lignocellulosic content of marsh
plants will reduce the biodegradability of the plants.
ANAEROBIC DIGESTION TECHNOLOGY

       Anaerobic digestion of wastewater-grown biomass has two
purposes—helping to stabilize and dispose the biomass and to generate
fuel.  These two objectives are, on the whole, compatible.  However,
the seasonality and amount of plant biomass produced in some of the
wastewater aquaculture processes, the nature of the plant materials
to be digested, and the high cost of conventional sewage sludge
digesters suggest that alternative digestion processes would be
desirable.  Conventional sewage sludge digesters have capital and
operating costs of about $0.015/lb of volatile solids [21].  Assuming
4.5 scf methane/lb of volatile solids, this corresponds to a methane
cost of $3.33/MBTU, or competitive with current or near-term natural
gas costs (currently $2.50/MBTU in California and expected to increase
to $3.50 by late 1980 or early 1981 [22]).  This does not include a
cost for the disposal of the sludge or the heating of the digesters.
Large (100,000 ft3) high-rate, masophilic digestion is assumed, yield-
ing about 1  scf biogas/scf digester.  The recovery of the biogas for
electricity generation would allow use of waste heat for heating the
digesters.  This appears to be the best alternative in most cases.
Another calculation for costs of anaerobic digestion using a con-
ventional stirred tank reactor was recently prepared by SRI Intl.
[23],  For a biogas plant using fresh cattle manure, a cost of $8.50/
MBTU was calculated.  However, a large part of the costs were for pre-
and post-processing (e.g. centrifugation of solids) and cost of manure.
       The high costs for conventional digestion systems suggest the
need for alternative processes.  The aquatic plants would need to be
further concentrated (for microalgae), shredded (for water hyacinths),
or possibly pretreated (marsh plants) to allow use of such digestion
processes.  More important, the loadings of standard high-rate sewage
digesters (2-8 g VSS/L/day and up) may not be readily achievable with
aquatic plants, particularly microalgae.
       Finally, the expected quantity and its seasonal variability
of the plant material would require a large digester capacity.  For
example, for hypothetical design of a 5 MGD microalgal system capable
of secondary treatment and partial tertiary treatment (N removal),
2,500 tons of algal material would be harvested per year versus only
                              450

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1,000 tons of primary sewage sludge [24].   In  that  design winter
algal production was about two-thirds  of summer production,  achieved
by assuming higher photosynthetic activities  in winter and  fewer
operating ponds in summer.  This is, however,  too optimistic,  and it
is doubtful that biomass productivity  in the winter months  could  be
more than 30% of the summer, even assuming cutting  down significantly
on growth pond operations in summer.  The process of algal  flocculation-
sedimentation currently being investigated is  likely to exhibit an
even greater variability in productivities [25].
       As discussed before, harvesting of water hyacinths  could be
spread out to allow a dampening of the strong  seasonal variations in
productivity.  However, any process depending  on nutrient  removal by
water hyacinths would produce prodigous amounts of  plant material. A
5 MGD system, assuming complete nitrogen removal at 40 mg/L of sewage,
would produce per day about ten times  as much  digestible solids (about
25 tons/day, assuming 3.3% N of dry weight) than primary sewage sludge.
Thus, a large digester capacity will be required.  The unavoidable
differences in summer versus winter harvest will, thus, require at
least a 20-fold increase in capacity,  even assuming it is  not necessary
to decrease in loading of the digesters.  This type of calculation
demonstrates the need for alternative, lower-cost digestion processes
for this biomass.  Only a brief descriptive summary of the status of
these alternatives is feasible here.
       Two main approaches to lowering the cost of the anaerobic
digestion process have been followed over the past  five years, since
the resurgence in interest in biomass energy resources.  One approach
was to increase the rate of the reactors by more sophisticated process
control, pretreatment of the feeds, increased mixing or heating, or
improved gas transfer.  This type of approach, which is based on the
assumption that process rates will  increase faster than costs, is best
exemplified by the two Pfeffer-Dynatech processes which are undergoing
full-scale testing in Florida—the  Pompano Beach plant which digests
solid wastes with sewage  sludge and the Bartow plant which digests
environmental feedlot wastes [26],  It does not appear, at present,
that these systems provide a significant  improvement over conventional
mixed tank reactors.  However, economics  can still  be  favorable with
waste treatment and by-product credits.   A better approach is that
of two-phase reactors which separate the  acid and methane bacterial
cultures  [27,28].  However, it  is  still uncertain whether such systems
represent  a  significant enough  improvement over conventional two-stage
systems.
       The other  alternative is  exemplified by  the gas recovery  from
landfills  [29], a very  slow, unheated,  unmixed  batch  process.
Similarly, gas  recovery  from anaerobic  ponds by  use of floating  gas
catchers  appears  to be  very promising  [30].  Digestion of animal
manures  in small-scale  plug-flow systems  made  of plastic material
are  the  method  of choice  for low-cost  digestion  of dairy wastes  [31].
As  lignocellulosics are  not a  significant problem with aquatic
plants  (except,  possibly,  for  marsh plants), temperature is the
most likely  limiting  factor in  their anaerobic  digestion.
        Augenstein [32]  reviewed the literature  and  found a  reasonably
good fit for data on  the  rate  constant for anaerobic  digestion  in a
typical  Arrhenius plot.   Each  ten degree  increase  in  temperature
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slightly more than doubles the rate of the reaction.   However,  it  is
a common experience that anaerobic digestion below 15°C becomes
extremely slow; thus, that may be considered the lower limit for the
process.  The same author also pointed out that mixing is not required
to overcome substrate diffusion limitations in an anaerobic  digester.
Thus, simply mixing the influent solids with the microorganisms
(e.g. a part of the effluent stream) should be sufficient for achieving
a good rate of anaerobic digestion.  The biggest problem is  to  avoid
the acid bacteria from overtaking the methane bacteria which results
in "pickeled" or "stuck" digesters.  Both buffering with CaC03  and high
inoculations are suggested.  The particular characteristics  of  waste-
water treatment with aquatic plants—here we have emphasized micro-
algae and water hyacinths—suggest that unconventional digesters such
as designed landfills, covered anaerobic ponds, plug  flow reactors,
and other similar alternatives are preferred over conventional  sewage
digesters.  These processes, however, need further testing and
verification prior to implementation.
       Probably the most promising approach to a high-rate anaerobic
digestion process is the "anaerobic filter" process which has recently
been applied to municipal sewage [33].  A variant of  this process--
the "expanded bed" reactor [31], based on a fluidized bed of small
plastic spheres on which microorganisms attach—is another example
of such an approach.  These concepts could have applications to the
digestion of aquatic plant biomass.
       Another consideration in anaerobic digestion of aquatic  plants
is the disposal of the residual digested sludge.  The high-cost al-
ternatives of conventional dewatering or even incineration are  not
applicable to wastewater aquaculture systems.  Essentially,  digested
sludge can be disposed of on land as a source of fertilizer  for plant
growth, recycled to the ponds, put on sludge drying beds, or buried in
a landfill.  The last option could be combined with the anaerobic
digestion option, particularly for the relatively low-mositure, high-
lignocellulosic marsh plants.   Land disposal becomes  expensive  when
suitable land is not available nearby.  The disposal  of sludges on
drying beds is a reasonable alternative; marsh plants can play  a
useful role in such a process  [34].
       Finally, digester effluents or the liquid supernatant fraction
could be recycled back to the  treatment ponds.  This, of course,
must not result in an overload of the system or a large expansion  of
it.  The relatively large volume of aquaculture wastewater treatment
systems allows the accumulation of considerable amounts of slowly
degradable solids.  However, it does not appear that  a large increase
in system scale could be justified solely on the basis of the fuel
that could be derived from any additional aquatic plant crop produced.
Thus, digester effluent recycle is only feasible when there  is  addi-
tional treatment capacity (in  summer), nutrients are  removed by non-
biological processes (e.g. ammonia volatilization), or no other al-
ternatives are feasible.
ENERGY RESOURCE BASES AND IMPACTS

       The fuel that could be derived from wastewater aquaculture is a
very uncertain quantity.  Some simplifying assumptions must be made.
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It will  be assumed that two different  levels  of  treatment will be
achieved—secondary (30/30 standards)  and  tertiary  (10/10 standards
plus 40  mg/L nitrogen and 10 mg/L phosphate removal).   For  secondary
treatment, we shall assume a biomass productivity of 60 MT/HA/yr
and an area of 1.3 hectare per 106 L per day  (12 acres/MGD).   For
tertiary treatment, we assume a 0.75%  phosphorus in the biomass and
a productivity of 80 MT/HA/yr (volatile solids basis)  corresponding
to an areal requirement of 6 HA/106  L/day  (55 acres/MGD) of growth
ponds (storage ponds will need to be used  in  winter).  It is also assumed
that the digestion process will require no significant amount  of the
output fuel (due to waste heat utilization or use of alternative
low-cost energy processes), and that each  kg  of  volatile solid produces
10 ft3 of methane gas.  This corresponds to a net 55%  conversion
efficiency, assuming 4.5 Kcal/g of biomass.   We  can then calculate
the fuel produced by the aquatic plant systems as 600  to 800 MBTU/
HA/yr or about 8.0 MBTU/MG treated for secondary standards  and 50
MBTU/MG treated for tertiary standards.
       It is interesting to compare this fuel output to total  energy
inputs in conventional wastewater treatment.   Hagan [35] estimates
for a 100 MGD plant 90,000 KW hrs for  secondary  treatment  and  150,000
KW hrs for tertiary treatment stages (with about net 10,000 KW hrs
recoverable  from primary treatment).   Assuming  10,500 BTU/KW hr
(a 32.5% conversion efficiency to electricity),  this corresponds to
9.5 MBTU/MG for secondary and 25 MBTU/MG for  secondary plus tertiary
treatment  (ignoring primary treatment, which  can cover influent
pumping energy requirements).  A different source [36] gives 12 MBTU/
MG for secondary treatment and 27.3 MBTU/MG for tertiary treatment
at a  15 MGD scale.  For  comparison, we must calculate the  input energy
requirements in the wastewater aquaculture systems.  This  input energy
is, unfortunately, far from certain.   In the case of high-rate
oxidation  pond systems,  the energy inputs (including influent pumping)
have  been  very roughly estimated as about 25% of outputs [37], al-
though they could  be  considerably lower.  An aerated water hyacinth
system, assuming an efficiency of 1.1   kg Oa per KW  hr  (1.8 Ibs 02
per hp hr)  [36], with  an efficient surface aerator  and a 125 mg/L
BOD5  to be met, energy requirements would be  114 KW hrs/106 L or
4.5 MBTU  per MG treated  (assuming no nitrification).   Harvesting and
shredding  of the water hyacinths  is likely a minor  energy  input.
Total energy requirements would  be at  least 60% of  outputs.  A combined
algal-water hyacinth  system would have a much lower overall energy
requirement as would  tertiary  treatment systems and marsh  plant systems.
For a working assumption, the  figure of 25%  of  energy  outputs required
for systems operations appears to be useful.
        A  final consideration  is  the energy conservation achievable with
wastewater aquaculture systems.   It is not quite valid to  compare
present conventional  technology  energy requirements with future
possible  aquaculture  technologies.  Conventional technologies are
rapidly developing energy-efficient processes,  and this must  be con-
sidered in any comparisons.   Also, as  land application becomes more
 important  and  "conventional",  the relative  advantage of wastewater
aquaculture would disappear.   Thus, a  15  MGD advanced wastewater
 treatment-land  application system would consume only  15% of the energy
 of conventional  processes [37].   Indeed,  it  would  be  possible to
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produce much more biomass fuels with a silviculture wastewater
treatment system than with aquatic plants (due to lower nutrient
and water requirements).  It appears that the best combination would
be a combined wastewater aquaculture-land application system [38],
Thus, for calculating energy conservation potentials, only half of
current conventional usage will be assumed.
       In the context of this discussion, it is, therefore, reasonable
to assume that a secondary wastewater aquaculture system of 15 MGD
could produce a net fuel output of 6.0 MBTU/MG and an energy con-
servation also of about 6.0 MBTU (50% of present-day activated sludge
requirements).  A tertiary treatment system would produce about 37.5
MBTU/MG of net fuel output and have an energy conservation potential
of 13.5 MBTU/MG (again, half of present-day conventional tertiary
treatment).
       As 1 MGD corresponds to 10,000 people, total energy production
(net fuel output plus conservation) amounts to 0.44 MBTU/person/yr
for secondary treatment and 1.8 MBTU/person/yr for tertiary treatment.
(This corresponds to roughly 0.1% and 0.4% of per capita energy re-
quirements, respectively).  In practical terms, likely energy contri-
butions by wastewater aquaculture systems will fall between these values.
       A final consideration is the total energy contribution by waste-
water aquaculture to U.S. energy supplies.  A number of limiting factors
must be considered—the need for tertiary treatment, the geographical
and climatic limitations, the capital investments in current technology,
the alternative low-cost wastewater treatment processes, and the
problems of acquiring sufficient land near urban centers.  Of a daily
U.S. municipal wastewater flow of about 25,000 MGD by the year 2,000,
it is doubtful that more than 10% could, in the foreseeable future, be
treated by wastewater aquaculture technologies.  This estimated market
penetration potential for wastewater aquaculture plants is based on
the data in EPA's 1978 Needs Survey [39].  In 1978 8.2% of the total
U.S. population (219 million) was served by tertiary treatment
systems (701 treatment plants).  This will increase to 35.1% of the
population (4,432 treatment plants) by the year 2,000 or 95 million
out of a 270 million population.  If treatment more stringent than
secondary is considered, then 9,321 out of 22,768 treatment plants
will require such a level of treatment by the year 2000.  However, of
the new plants to be constructed (3,026 plants) which provide treat-
ment more stringent than the secondary, 66% will be smaller than 0.1
MGD and 97% smaller than 5.0 MGD.  However, the new advanced treatment
plants above 5 MGD have about 80% of total flows or approximately
2,500 MGD.  New construction would be the prime target for new
technologies such as wastewater aquaculture.  Enlargement and/or
upgrading of existing plants is of lesser potential for the application
of wastewater aquaculture processes.   The total dollars (first quarter
1978) required for such stricter treatment plants is $20.5 billion.
Another view of the potential for wastewater aquaculture technologies
is the number and flows of new required, but not yet funded, treatment
plants which use land treatment, stabilization ponds, or aerated
lagoons  which correspond to a total  flow of almost 2,000 MGD [39].
       Of course, no realistic market penetration analysis is feasible
at present in view of the lack of development of wastewater aquaculture
technology.   However, sufficient data exist to indicate that such
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technologies could be developed in the near term if sufficient R & D
resources are immediately committed, if full-scale demonstration
projects are planned for the early 1980's, and if planning for new
facilities takes into consideration the likely availability of these
novel  technologies by the nnd-1980's.   Under such a scenario a 10%
market penetration for wastewater aquaculture by the year 2000 or
2,500 MGD capacity appears a realistic estimate.  Depending on the
level  of treatment, this flow would result in a net energy contri-
bution to U.S. supplies of between 0.01 and 0.05 x 1015 BTU, cor-
responding to 0.01 to 0.05% of future U.S. energy supplies (assuming
100 x 10   BTU as total future energy usage.  More optimistic assump-
tions are defensible, but still would restrict energy from wastewater
aquaculture to 0.1 x 1015 BTU [4].  Thus, it must be concluded that
energy from wastewater aquaculture will be a minor future U.S. energy
source.  However, energy from aquatic plant biomass will be an im-
portant component and consideration in the development and imple-
mentation of wastewater aquaculture technology.
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        Instit. of Sas Technology ,  Chicago,  111.  (1978).

19.   Klass, D. Institute of Gas Technology, private communication.

20.   Xoegel, R. et al. Improvement and Evaluation of Techniques for the
        Mechanical Removal  and Utilization of Excess Aquatic Vegetation.
        Water Resources Center, Univ. of Wisconsin (1978).

21.   Environmental Protection Agency.  A Guide to the Selection of Cost
        Effective VJastewater Treatment Systems, Wash. D.C. (1975).

22.   Pacific Gas and Electric, personal  communication (June 1979).

23,   Jones, J.I. et al. Mission Analysis for the Federal Fuels from Biomass
        Program, Vol. V, NTIS TID-29093 COec. 1978):
24.  Benemann, J.R. et al.  Design of the Algal Pond System of the Photosyn-
        	   actory.  Fi
        CalifV, Berkeley. NTIS # HCP/T3S48-01 (June 1977).
thesis Energy Factory"!   Final  Report.  San.  Engr.  Res.  Lab., Univ.  of
25.  Senemann, J.R. et al. Large-scale Freshwater Hicroalgal Bionass Production
         for  Fuel  and Fertilizer.  Final Report. San. Engr. Res. Lab.. Univ. of
         Calif., Berkeley. NTIS~#  SAN 0034-1  (April 1978).

26.  Wise, D.L. and R.L. Wentworth  (eds.) Fuel Gas Production from Animal and
         Agricultural Residue  and  Siomass.  NTIS COO-2991-34  (Kay 30, 1978).

27.  Gosh, S.  and D.L. Klass.  "Two-Phase Anaerobic Digestion." in Symp.  Papers
         Clean  Fuels from Bt'omass  and Wastes,  Instit. of Gas  Technology,  Chicago,
         111  (1977).

28.  Massey, M.L. and  F.G. Pohland.  "Phase Separation of Anaerobic Stabilization
         by Kinetic Controls." J.  Water Poll.  Cont. Fed. 50:2204  (1978).

29.  James,  S.J.  and C.W. Rhyne.  "Methane Production Recovery and Utilization
         from Landfills." Symp.  Papers Energy from Biomass and Wastes.  Inst.
         of Gas Tech.,  Chicago/Ill.  (1973)T

 30.  Chittenden,  J.A.  et al.  "Control of Odors  from an Anaerobic Lagoon
         Treatment Meat Packing Wastes." in Proc. 8th flat!.  Symp. Food  Pro-
         cessing Wastes, E.P.A"  (Aug.  1977).

 31.  Jewell, J.W. et al. Anaerobic  Fermentation of Agricultural  Residue:
         Potential for  Imorovement and Imolementation, Final  Report.  Dept. of
         Energy (Feb.  1978).
                                            457

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32.  Augenstein, 0,C. "Technical  Principles of Anaerobic Digestion."  un-
       published (1978).

33.  Pitt, W.W.  and R.K.  Genung.  "Pilot Plant Demonstration of an  Anaerobic
       Fixed Film Bioreactor for  Wastewater Treatment."  in D.L. Wise and
       R.L. Wentworth (eds.) Fuel Gas Production from Animal  and Agricultural
       Residue and Biomass. NTIS  COO-2991-34 (May 30, 1973).

34.  Seidel, K.  "Purification of  Water by Means of Higher Plants." Article
       translated from Naturwissen Schaften 12, 289-297 (1970).

35.  Hagan, R.M. "Energy  Requirements in Wastewater Treatment, Part.  2." Water
       and Sewage Works 52 (Dec.  1976).

36.  Environmental Protection Agency, Energy Conservation in  Municipal  Waste-
       water Treatment. EPA 430/9-77-011 (March 1978).

37.  Benemann, J.R. and B.L. Koopman, unpublished.

38.  Benemann, J.R., B.L. Koopman, and W.J. Oswald.  "A Combined Aquatic-
       Terrestrial Wastewater-Biomass System." Proc.  of the ASCE Environmental
       Engineering Division Specialty Conf., Jack Tar Hotel,  San Francisco
       (July 9-11, 1979). pp. 665-671.

39.  Environmental Protection Agency. 1978 Needs Survey.EPA 430/9-79-002.
                                 458

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          AN OVERVIEW OF THE LEGAL,  POLITICAL,  AND  SOCIAL
      IMPLICATIONS OF WASTEWATER TREATMENT THROUGH  AQUACULTURE

                        Loretta C.  Lohman
                        Research Associate
                        Denver Research Institute
                        University of Denver
                        Denver, Colorado  80210
INTRODUCTION
        Although technical investigations into the use of aquaculture
for food production have been underway for a number of years,  wastewater
treatment by aquaculture is a fairly recent subject of research in this
country even though it was an accepted method in Germany and Russia 40
years ago.^  A review of the literature reveals that only a few of the
ongoing or recently completed studies even briefly touch on legal or
social problems affecting wastewater aquaculture.   Since the bulk of
research has been limited to test operations or laboratories,  legal,
social, and political implications have been little considered except
in matters involving the human food chain or in addressing legally
defined standards for post-treatment water quality.

        This paper, then, is an overview designed to highlight those
legal, political, and social elements which are likely to be common to
any full-scale aquaculture system for wastewater treatment.  One such
common element would be that of adequately meeting any federal and state
health, safety, and operating standards, as well as any criteria applied
to the particular treatment process.  Other legal, political and social
factors, which neither involve regulatory criteria nor have the benefit
of specific research, can be extrapolated from a review of observed
reaction to water resource management and policy innovation in other
areas, such as reuse.  For example, the rigor of specific aquaculture
criteria applied because of its innovative or unfamiliar technology
could lead to diverse political reactions similar to  those faced by
land application or groundwater recharge proposals.   In turn political
reaction can affect social or public acceptance of innovative wastewater
treatment methods.

        Specific examples of legal, political, or social implications
will be drawn from California's experiences for several reasons:

        • California has several  aquaculture projects  in the proposal
          or pilot-plant phase;

        • Certain elements of the appropriation doctrine are appearing
          in the permit systems under  creation in riparian  states;

        • Climatic conditions in  California are more  suited to aquaculture
          than  those of many other  states;
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        • California is an area of constant innovation in water resource
          use and management.

        Public attitude shifts, political controversies, and environmental
reactions to water resource  proposals have all occurred and been  studied
in California.  Hence, data  from which material applicable to wastewater
aquaculture can be derived are abundantly available and can be analyzed
based upon extensions of previous studies of public responses to  water
innovations.

        It is also important to note that, because this paper is  a
judgmental overview of political and social implications, specific names
and incidents will be omitted unless their inclusion is necessary for the
presentation of an accurate  picture.  The author's intent is to provide a
legal and socio-political outline of areas which will or are likely to be
affected by wastewater aquaculture and which will thus need to be addressed
before any full-scale treatment plants are put into operation.


LEGAL FACTORS
        It is the legal responsibilities and obligations of the various
levels and agencies of government—federal, state, local, water allocation,
water quality, and health—that provide the framework in which the politics
and social reactions of groups and individuals take place.  Innovative
treatment of wastewater by aquaculture can be governed at each level.

        Although the legal implications generally flow downward from
federal to state to region or town, water law, particularly concerning
water quality, displays complex interrelationships with each level
dependent on that above and below.  Even so, this paper will attempt
to break the legal discussions into federal and state sections to simplify
the presentation.


Federal Legislation

        Wastewater aquaculture will be subject to a veritable "alphabet
soup" of federal statutes, regulations and agencies, including NEPA
(National Environmental Policy Act), NWPCA (National Water Pollution
Control Act) and its 1972 Amendments, NPDES (National Pollution Discharge
Elimination System) permits, EPA (Environmental Protection Agency), the
Safe Drinking Water Act, and possibly FDA (Food and Drug Administration).
Although not exhaustive, this list and the regulations pertinent to it
contain most of the elements of concern to an aquaculture wastewater
treatment proposal.

        National Water Pollution Control Act.  This act and its 1972
Amendments  (Pub. L. 92-500) constitute the most direct control over
wastewater discharges.^  Sections of the act establish stream standards  (303),
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effluent limitations tied to best practicable technology (301),  toxic
effluent standards (307), and thermal discharge standards (318),  all
of which can determine whether or not aquaculture treatment is the
best technology for a given discharge.  The discharges themselves are
controlled by NPDES permits (402), issued either by EPA or its designated
state agency.  Specifically aimed at wastewater treatment works,  the
permits allow only those effluent discharges which meet federal and
state defined standards.  Finally, provisions for areawide waste  treat-
ment planning (208) have essentially required that each area of every
state devise a plan to control or reduce all current and future sources
of water pollution including projected uses of energy resources and
energy development.  A wastewater aquaculture facility might not  meet
the needs of the 208 plan for the area of installation.

        The 1977 Amendments to NWPCA  (Pub. L.95-217) may constitute
another hazard to wastewater aquaculture facilities.  One of its
provisions establishes a priority listing of wastewater treatment
plant projects eligible for funding through the Clean Water Construction
Grant Program.  In interpreting the provision that funding be given to
only those projects which result in compliance with the "enforceable
requirements of this Act," EPA has drawn regulations which will probably
preclude assistance for multipurpose wastewater reclamation projects
unless pollution control is the primary purpose.^  Since, by definition,
aquaculture treatment is multipurpose, federal funding assistance could
be jeopardized under these regulations when tied to the best practicable
technology requirements for wastewater treatment works defined in Pub.
L. 92-500 and in individual NPDES permits.

        Safe Drinking Water Act.  Since 1962 the U.S. Public Health
Service has maintained drinking water standards.   In  1977  the most
recent primary drinking water regulations were given  statutory
recognition with the passage of Public Law 93-523.  Although the
standards apply to  the first step in  a water system,  they  can affect
the last—wastewater treatment—because most treatment plant discharges
enter a watercourse which in turn is  a source of drinking water  for a
downstream user.   Safe drinking water regulations  control  maximum
allowable levels of contaminants as well as  the underground injection
of wastewater.  If  an aquaculture treatment system does not adequately
remove controlled  substances, downstream users or  a public health agency
could seek cease and desist orders on any discharges.  Such an action
could, in turn, bring a  facility  into violation of state water rights
laws.  If the inadequately  treated water  is  to be  used to  augment under-
ground supplies, a prohibition against spreading or injection could  lead
to serious local water shortages  as well as violation of various permits
for operation.

        National Environmental Policy Act.   This act  requires that  a
detailed environmental  impact statement  (EIS) be included  in every
recommendation, report,  proposal  for  legislation,  or  other major federal
action—such  as funding  a  treatment plant—which significantly affects
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the quality of the human environment.  Many  states require a similar
statement in areas where the federal requirement does not apply.  An
aquaculture wastewater treatment  facility will likely be subject to
state or federal EIS's for a number of reasons, including:

        • land use is likely to be greater than with mechanical
          treatment plants;

        • insect production, especially significant mosquito breeding
          problems, will be a health factor;

        • area residents will be  concerned about odor and physical
          safety, particularly the attraction ponds present to children:

        • water users along watercourses connected to the aquaculture
          system will require guarantees that treatment mediums  (hyacinth,
          duckweed, etc.) will not escape and clog other water works.

        Since the time, expense,  and frequent legal controversies
surrounding approval of an environmental impact statement often delay
and increase the cost of a project, the Council on Environmental Quality
(CEQ) has promulgated regulations requiring  an assessment procedure to
determine if an EIS is needed as  well as streamlining and consolidating
the EIS process.   However, the assessment procedure involves environmental
agencies, project applicant, and  the public  and thus becomes a political
and social tool in addition to a  legal requirement.  Any aspect of the
EIS process can then, singly or combined, provide impediments to installation
of a wastewater aquaculture facility.

        Food and Drug Administration.  The FDA, particularly through the
Delaney Amendment banning any additive found to induce cancer in man,
could play a role in determining  the feasibility of wastewater aquaculture
even though the by-products are not intended for use in the human food
chain.  For example, by-product application  as fertilizer could be severely
controlled if the crop fertilized is used for animal feed for growing
animals to be consumed by humans.  Any wastewater aquaculture system will
have to satisfy not only normal waste treatment standards but additional
health—related standards if by-product use  in any way relates to the food
chain.  Interestingly enough, thermal wastewater aquaculture will probably
not encounter the same difficulties, as heat and salinity are often the
major pollutants found in such waste.
State Statutes and Regulations

        Much of the state law regarding water quality is derived from
federal statutes and standards, particularly those standards relating
to drinking water standards and effluent discharges.  However, the states
can and sometimes do set stream standards, discharge requirements, or
water use limitations which are stricter than federal rules.  Furthermore,
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they control the siting, operation and certification of wastewater
treatment plants and the certification of plant operators.   States
also have, except in cases of interstate or international compacts,
control over rights to use water and obligations to protect all water
users.  This last power can be of particular interest to proponents
of wastewater aquaculture.

        Water rights law.   In this country, water rights are obtained
under the riparian system or under the appropriation doctrine.  The
riparian system gives rights to use of water to the owner of land
abutting a natural watercourse.  This system, generally found in the
more humid Eastern states, has in recent years of water scarcity been
modified by most states to include principles of reasonable use, pol-
lution control and a variety of permit procedures limiting the uses
and duration of a water right.  The appropriation doctrine is a. priority
system, "first in time, first in right," which establishes rights to use
water on the basis of the date of appropriation, modified by beneficial
use and use preference standards.  Under both systems, more state controls
are developing in the face of population growth, water scarcity, and the
strains of increasing pollution.  In either system it is likely that
a state has or will obtain enough control over water to protect all
water users from diminishment of water quantity or quality.  However,
because the author is more familiar with Western appropriation, specific
problems pertinent to wastewater aquaculture will be addressed under that
doctrine.

        Specifically, wastewater aquaculture may damage  the rights of
downstream water users  to either a specific quantity or  quality of
water.  The situation is  similar to that encountered in  land application
wastewater treatments wherein downstream users have been deprived of an
amount of water—effluent—which has made up a portion of  their water
right.  There has even  been at  least one case where downstream users have
sued  for  their right to dirty water because they had come  to  rely on the
nutrients it contained.   Diminishment of quantity  could  occur  when  the
aquaculture process is wetlands treatment; or if the process  doesn't meet
discharge standards; diminishment of  the expected  quality  could occur
if  the aquaculture works  either too well or not well enough.   In  either
case, affected users could sue  for damages covering a number  of years
or  obtain cease and desist orders.  In California, and any other  state
with  anti-paralleling statutes, operating income from  the  sale of the
treated water could be  in competition with  fresh water purveyors  and
thus  be restrained even though  ownership of such water  is  usually the
plant's until it enters  a watercourse.

        The questions of  water  ownership and historic  patterns of water
flow  are  extremely complex and  vary somewhat  in every  state.   However,
any innovative  use or treatment of water could  impact  on historic patterns
or  on other users  and therefore must  be addressed  when  considering  an
aquaculture  treatment  facility.   The  preservation  of  the watercourse  from
the treatment medium will be  among such concerns.
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        Public health.  Although all states have water quality laws
and regulations, previously described federal requirements cover similar
concerns.  It is the public health aspects of aquaculture, particularly
as exercised in discharge permits, that will most affect any facility.
Not only do states exercise direct control over wastewater treatment
facilities—plans, construction, operation, maintenance, and operator
certification—but most of them also exercise direct authority over
or have major influence on the issuance of NPDES permits.  Items which
a permit will address are likely to include:

        • identification of any diseases or parasites resulting from
          the project which could affect aquatic life outside the project;

        • identification of the plants or animals to be used in the
          treatment;

        • potential for escape of the treatment medium from the project
          area;

        • concentrations in treated water of pollutants to be controlled;

        • uses of the process by-products;

        • concentrations of carcinogens or mutagens in the by-product;

        • reliability of the system;

        • identification of emergency procedures to handle surges of
          toxic materials;

        • operator training requirements.

Naturally, the initial state concerns will focus on whether or not the
process will meet the defined standards for secondary or tertiary treatment,
That first must be proven.

        Guarantees against the escape of treatment medium can fall under
health, water rights, or political concerns depending on the plants or
animals and the geographic area in which such plants and animals are
used.  This factor, combined with the need to protect public health,
could determine what types of plants and animals may be used in any
particular aquaculture facility.

        Uses of by-products will likely be controlled in the permit
at the state level since the food chain is not likely to be involved
in the near term.  This permit will involve regulation of any direct
use or application of the treated water as well.  For instance, pasture
irrigation may only be permitted up to three days prior to its use to
allow solar and wind sterilization of the  fodder.
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        System reliability, emergency procedures and operator training
will be determined through state waste treatment regulations.  These
will have to be expanded to include the innovative techniques of aqua-
culture and may include requirements as to biological training, or
the like.

        Each of these factors will probably be handled at a state level
or with a large degree of state input to the NPDES process.

        Although it is not possible to present an inclusive listing
of potential legal problems, one other which is reflected at a state
and local level, and may be included in the permitting process, is
worthy of note.  That is the possibility that the ponds or marsh
areas necessary to aquaculture could serve as an insect breeding
ground, particularly for mosquitoes, would demand attention.  This
is not only a potential health hazard but could be classified as a
public nuisance and dealt with as such.
POLITICAL ELEMENTS

        The  legal framework not only  defines  the  obligations and regulations
of water use, water  quality, and public health and  safety, but  it also
creates the  forum in which political  activity takes place.  Thus it
can be difficult to  separate the legal from  the political because of
the ubiquitous  nature  of  politics.  Indeed,  any reviewer of water manage-
ment  literature will have noted that  most  legal-institutional studies are
unable to separate the two, with a  resulting presentation of  the material
in essentially  legal terms.  In an  effort  to clarify  the meaning of political
factors to be discussed,  this  paper first  defines institution as the
actual operating activities, as shaped by  administrative policy and
precedent, of a person or agency charged with application of  the legally
defined processes germane to wastewater aquaculture.   These  institutions
are the political arena directly pertinent to establishment  of  a facility.
This  definition directs the  focus  to  the agencies and actors  most concerned
with  the activities  involved  in the planning, construction,  funding,
operation, maintenance, and  permitting of  wastewater  treatment  plants.
Public reaction, including political  response, is addressed only as one
of the influences on the  institutional players.

        Patterns of  influence. No  agency  or administrator works in a
vacuum.  Each agency or administrator, in  addition to specific  legal
responsibility, is part of a larger governmental  entity with  broader
and even different purposes  and goals.  Such factors  influence  an
agency's or  administrator's  approach  to the direct responsibilities
at hand.   In proposing a  wastewater aquaculture  facility, an  agency
or administrator might be subject  to  such  influences  as:

         •  national water  policy emphasizing conservation  and  innovative
           water treatments;
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        • EPA interpretations which could jeopardize funding of multi-
          purpose projects;

        • requirements  to meet safety standards which are not fully
          defined;

        • state agency  desires to maximize water use;

        • federal or state standards on effluent discharges;

        • area land use or growth policies;

        • compact commitments to deliver water to another entity;

        • policies favoring one type of treatment over another;

        • public concerns for environmental and safety factors;

        • interagency disagreements on practicality or feasibility.

The pattern which emerges is interrelated, complex, and somewhat confused.
National executive policy, which should be carried out by EPA, is instead
susceptible to narrow interpretation, as in rules for funding multipurpose
projects.  State policy, based on water law and historic uses of water,
may preclude some types of treatment (such as wetlands) and may conflict
with national policy.   Within the states', agencies with different legally
defined missions may hinder each other or local initiatives.  Land use
and growth policies may conflict with water treatment proposals, and the
like, as policies and agencies bounce against each other and create demands
upon a project proposal.

        Efforts to establish aquaculture facilities in California can
illustrate many of these elements.  It is state policy to optimize water
use through conservation, treatment and recycling.  However, reuses such
as groundwater replenishment and food chain irrigation have often been
hindered by the state health department, and aquaculture plants have yet
to receive discharge permits.  In addition, federal funding under the
Clean Water Construction Grant Program is in question for the types of
multipurpose projects considered in California.  Finally, some marshland
maintenance with reclaimed water is under attack by local mosquito
abatement districts.

        Chemehuevi Wastewater Reclamation Facility.  One of the most
graphic examples of the conflicts facing wastewater aquaculture can
be found in the efforts of the Chemehuevi Indian Tribe to build a facility
on their reservation near Lake Havasu, California.  The plant was to be
funded by a grant from  the Economic Development Administration (EDA), U.S.
Department of Commerce.  It was to treat raw domestic sewage to better
than secondary standards by means of an aquaculture system using water
hyacinth plants and teleost fish.  Effluent was to be used to irrigate
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reservation crops or to be evaporated in the desert.  By-products were
to be harvested and used for an unspecified purpose, possibly for sale.-3
The California State Office of Economic Opportunity strongly supported
the project, with endorsements from the Bureau of Indian Affairs and
the federal Office of Economic Opportunity.

        Early reaction to the proposal was addressed to the California
Water Resources Control Board, the Colorado River Basin Regional Water
Quality Control Board, and Region 3 of the U.S. Bureau of Reclamation.
The Colorado River Basin Regional Water Quality Control Board acted as
the lead agency in discussing comments and negotiating with the parties.

        Comments objecting to the use of water hyacinths were received
from the Imperial Dam Advisory Board, the Coachella Valley County Water
District, Imperial Irrigation District, Wellton-Mohawk Irrigation and
Drainage District, and the Metropolitan Water District of Southern
California.  The Colorado River Board of California participated in
the discussion and kept informed on the negotiations.6  The major
fear was that water hyacinths could be accidentally introduced  into
the Colorado River system, would then interfere with pumping operations
and clog watercourses.

        Under such circumstances the National Environmental Policy Act
required an environmental assessment and possibly  an Environmental
Irapact  Statement before the grant could be made.   Because of the degree
of opposition generated by the proposed use  of water hyacinths,  the
Chemehuevi Tribe switched to  use of indigenous duckweed and  obtained
a negative determination as to the need for  an EIS.

        This negotiated settlement carried four  EDA conditions:   (1)  the
Tribe had to notify local entities of any  change  from  duckweed  as  the
treatment plant;  (2)  EPA, Bureau of Reclamation,  and the  Forest and
Wildlife Service would  form an advisory group  to  evaluate the  impact
of any  change in treatment plants;  (3) approval  from appropriate health
agencies would have to  be obtained before  the  sale of  fish  or  other  food
products; and  (4)  certain design standards would  have  to  be met at  the
pumping station.^  Unfortunately,  those conditions could  not be enforced
as neither  a state agency nor EPA  had jurisdiction over what could  be
considered  an "independent  Indian  nation."  The  only recourse  would  have
been  a  civil suit  by  a  damaged party after damage had  occurred.

        Because  of the  concerns  of local  and federal agencies  responsible
for water use and  quality,  the EDA grant  funds were delayed and the Tribe
cancelled  their  aquaculture  plans  in  favor of  a  conventional wastewater
treatment  plant.   In  part,  this  occurred  because the Tribe,  although
dependent  on  government aid,  was not  subject to  normal rules and could
not  receive needed state  aid  for construction  of collection facilities
without surrendering  some  autonomy and  submitting to some state jurisdiction.
Furthermore,  the questions  of adequately  meeting safety  standards,  ob-
 taining discharge  permits,  and  receiving  permission to sell by-products
 loomed  as  future problems  which  could  have created more  opposition to the
project.
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        The Chemehuevi proposal illustrates the conflicting policies of
state and federal agencies as combined with vested interests of agricultural
groups, water districts, and Indian improvement proposals.  While no one
wished to deny the Tribe's right to advance, the implications of the
method caused a number of serious political obstacles.

        Role of agency/administrator.  All of these previously discussed
factors come to bear on the actors who are on the line, the people who
make up the agencies related to wastewater treatment, public health and
water management, and who must take the daily actions necessary to
administer the varied elements of these programs.  Depending on agency
mission these actors are subject to a variety of clientele seeking to
preserve or advance a particular interest.  It is essentially these
agency personnel, and the way they perceive their roles, who shape
legal obligations into a particular administrative process.  Their
role identification performs a dual function:  it guides the develop-
ment of policy which guides administration of legally defined duties;
and it defines the type of relationships that are established between
the agencies.

        For example, an administrator's distrust of aquaculture treatment
processes could extend to his agency procedures—making necessary permits
or regulations more difficult to obtain or follow.  In another way,
traditional agency rivalry or interpersonal mistrust could hinder
acceptance of a proposal.  Agencies are generally accustomed to responding
in a traditional manner to familiar request from an accustomed clientele.
Insertion of an innovative process requiring unusual types of administrative
action involving differing agencies can exacerbate underlying tensions or
introduce new ones.

        Because of the myriad of agencies, administrators and vested
interests who might be involved in a specific aquaculture project it
is difficult to construct a "typical" political scenario.  For instance,
in Hercules, California, the city government opted for a wastewater
aquaculture facility because the regional council of governments
blocked funding for a traditional facility.  Hercules was not scheduled
for growth according to regional plans.  Because the Hercules' govern-
ment has chosen to grow and must therefore have additional treatment
facilities, the aquaculture facility was chosen because it is less
expensive and is entirely city financed."  This scenario places a
unified city government in opposition to regional, state and federal
agencies.  At this point, state health officials have issued the necessary
discharge permits for complete operations with a requirement for four times
the frequency of normal testing.  Even so, because it was a city decision—
"us against them"—little interagency rivalry had opportunity to emerge.

        Such rivalry was beginning to emerge in the Chemehuevi project and,
as more wastewater aquaculture facilities are proposed (especially wetlands
processes), vested interests for traditional patterns of water use and
treatment could come more into conflict x^ith those agencies charged to
seek out innovative procedures.
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SOCIAL IMPLICATIONS


        As the political elements spring from the legal factors, so
the social implications of wastewater aquaculture spill out from the
political.  Interagency dispute over a project, professional distrust
of the procedure, or an attitude similar to Hercules' "us vs. them,"
can all contribute to public attitudes and responses.  The presentation
of information and interpretation of scientific data, along with the
method of citizen participation in a proposal, also influence and
direct public response.

        All in all, societal positions relating to wastewater aquaculture
treatment can be expected to encompass a broad range of individual and
group concerns about water supply and water quality.  Such affected parties
Include not only the average citizen and the downstream water user but
also organized interest groups—farmers, Chambers of Commerce, labor
unions seeking more jobs, homeowners» and municipalities.  It is the
water or health administrator's perception of these societal positions
which is ultimately reflected in many of his actions,

        General attitudes.  It has been assumed, but never specifically
demonstrated that wastewater aquaculture would encounter problems of
public acceptance; many of the social impacts encountered in water reuse
projects can be expected  to be associated with proposed aquaculture
projects.  A discussion of reuse attitudes can be helpful in under-
standing public concerns  about and responses to innovative water use
proposals.  It should be  noted, however, that an interviewee's  failure
to express disgust at a proposal cannot be taken as implicit approval.
The one study which attempted to derive aquaculture attitudes from water
reuse surveys made this error.^  The fact that 56.4 percent of  respondents
oppose drinking reclaimed water does not mean that 43.6 percent are  in
favor of it or would, by  the study's extension, serve as a market for
food grown in wastewater.  To infer such is .a careless manipulation  of
data.

        A review of the literature does suggest that the general public
is more flexible in attitude toward water innovations than is the professional
water manager or health agent.10  This might be due  in part  to  the public's
lack of complete information about specific factors  such as  toxic contami-
nants, but it is also  the result of long-term acceptance of and belief in
water-system reliability  and safety.  Along with proper presentation of a
wastewater aquaculture proposal  this attitude will probably aid acceptance.

        Several droughts  and water supply problems that have occurred
 throughout the nation  in  recent years have created a broad public awareness
 of water problems and  a willingness to adapt  expectations  to meet them.
 One public response to these problems has been a willingness to accept
 innovative uses of water. Reuse as a general  concept has had wide
 public  acceptance once health and safety factors, and  the  protection of
                                          469

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existing water users have been adequately addressed.  Such a response
is likely for wastewater aquaculture which does not form part of the
human food chain.

        In Denver, an 84.1 percent approval was given to potable reuse
of wastewater if the resulting water quality were the same as that
currently supplied to each home.H  Despite some difficulties in
transferring the results of this survey, a reasonable extrapolation
from these data could find as many as 70 percent willing to use aquaculture
products in the food chain if their quality was the same as that presently
obtainable elsewhere.

        The only aquaculture project nearing operation is in Hercules,
California.  Citizens in that city, in a series of public meetings, were
impressed by the energy conservation aspects and possible by-product
uses for mulch and commercial fertilizer.12  No organized opposition
surfaced, probably because disposal has bee*n, and will temporarily be
deep-water outfall and not part of another's water supply.  Such easy
acceptance will not continue if effluent fails to meet health standards,
or if odor or insect growth cause any area nuisances.

        Nor will wastewater aquaculture meet so little opposition in
areas where effluent makes up part of downstream water supplies, where
other treatment alternatives are readily available, or where a less
rigid political situation exists.  Like reuse, wastewater aquaculture
will be most acceptable where risk of body contact or ingestion is
remote and nuisance variables, such as excess mosquito production,
are kept under control.

        Environmental concerns.  Preservation of water quality and
the amenities of natural stream flow—vegetation, wildlife, recreation—
are at the root of environmental concerns with water management.  In
essence, wastewater aquaculture by wetlands processes would be generally
acceptable environmental goals.  However, aesthetically displeasing water,
in which the odor, taste or appearance is bad, could raise environmental
concerns.  The uses of land in an urban area can also attract environmental
interest.  Aquaculture is generally more land consumptive than conventional
treatment methods and could still create odor, appearance, or related growth
problems.  Control of plant environs will be necessary to satisfy aesthetic
as well as health concerns.

        Demographics.  The expected public response to a wastewater
aquaculture project, as well as the kinds of environmental concerns
expressed, will depend in large measure on the makeup of the population
affected.  In a populace with a tradition of citizen involvement, managerial
unease about aquaculture could be reflected in public reluctance to
innovate in an area as sensitive as wastex^ater treatment and food
production.  An understanding of the involved population is of particular
importance.  For example, some of the "sun-belt" locations most available
for wastewater aquaculture treatment might have a disproportionately older
                             470

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or more politically conservative population  (such  as  Palm  Springs,
California, or Miami Beach,  Florida)  which could be less receptive  to
innovation, particularly in  water treatment  or  use.

        Other factors which, in combination  with age  or political posi-
tion, will play a role in social acceptance  or  rejection of  wastewater
aquaculture include education level,  income,  type  of  work, and citizen
involvement.  An honest, but carefully designed, education and informa-
tion program will reflect these factors and  address those  issues which
most concern the affected population.
CONCLUSIONS

        As in any area affecting the uses  and  quality of water,
wastewater aquaculture faces legal,  political  and  social complexities
of great scope.  The truism that sufficient funding can overcome just
about any water problem is only partially  true in  this instance.

        Certainly sufficient monies  will diminish  any water rights
problems if damages could be paid or rights purchased.  However,
water quality is dependent on the state-of-the-art technology.  Money
alone is not sufficient to clean water if  the  technology used is
inadequate.  If aquaculture technology cannot  adequately meet health
and safety standards some other form of treatment  will have to ensue.

        Lead agency.  One of the ways to deal  with the legal demands
and resulting political conflicts which could  face a wastewater
aquaculture proposal would be the establishment of a lead agency  to
coordinate planning, public information, and legal requirements.  Such
an agency could address the specific concerns  of involved federal and
state agencies from a single information source.  Political issues,
such as those which might result from the EIS  process, could be
handled in a consistent manner and,  at the same time, be examined or
included in the proposal.  In Hercules, the city council served as a
lead agency, while the Chemehuevi project suffered because response
and authority was apportioned between the Tribe, EDA, and the California
State Office of Economic Opportunity.

        Incentives.  Although the national water policy presents  a call
for innovative methods of water use and treatment, EPA interpretations
of funding regulations cast doubt on the feasibility  of funding innovative
multipurpose facilities.  Thus  the  only real  incentive, at present,  is
the lower construction and operating costs of a wastewater aquaculture
facility.  These  savings could  be offset by discharge  restrictions,  extra
testing requirements, or limitations on by-product use.  Until  the
incentive to innovate is clear, outweighing extra  demands  for
educational and  environmental safeguards,  wastewater  aquaculture  will
not receive wide  consideration.
                                      471

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        Citizen participation.  The legal requirements upon wastewater
aquaculture have to be dealt with in a legally prescribed manner.
However, many of the social and political implications of such a
project can be addressed through a properly designed citizen participation
program.  As was noted earlier, the public is sometimes ahead of the
professionals in willingness to innovate.  A good program could allow
them to lead rather than react.

        Hercules' program, because it is a small town, was simply a
series of public meetings for the exchange of views.  Different circum-
stances might require more formal programs.  The EIS procedure prescribes
a public participation formula which could be adapted; round-table
sessions could be scheduled; newspaper debates could be instituted;
attitude surveys could be conducted and discussed.  In short, there
are myriad ways of developing public participation which could be
adapted to a particular community.  Only one rule is unchangeable—
all official presentations must be completely honest.13
ACKNOWLEDGEMENTS
        The author wishes to thank the many students of aquaculture
who took time to discuss various ideas with her.  J. Gordon Milliken
and Professor Terence J. Lohman contributed editorial review and stylistic
guidance.
                             472

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                             FOOTNOTES
 1.   Steel,  Ernest W., Water  Supply and  Sewerage, New York:  McGraw-Hill
     Book Company, Inc,  1947, pp. 490-491.

 2.   See:  MacArthur, Gregory,  Some Ecological  Implications of  the 1972
     Amendments  to the Federal  Water Pollution  Control Act, Denver:
     Rocky Mountain  Center  on Environment,  September 17,  1973;  and,
     A Legislative History  of the Water  Pollution Control Act Amendments
     of 1972;  Vol.  I and II, Washington, D.C.:  Congressional  Research
     Service,  1973.

 3.   California  State Water Resources  Control Board, Office of  Water
     Recycling,  "Background Information  Regarding Funding of Water
     Reclamation by  U.S. Environmental Protection Agency," April  17,  1979.

 4.   Council on  Environmental Quality—National Environmental Policy
     Act,  "Implementation of  Procedural  Provisions; Final Regulations,"
     43:230  Federal  Register, part  IV, Wednesday, November 29,  1978,
     pp. 55977-56007.

 5.   Description, Attachment  to WRCB Form 200  (2-72) Rev. 6, November
     10, 1976; and  Solar Aqua Systems, Inc. Process  description.

 6.   Colorado River  Board of  California, memorandum, July 18,  1977.

 7.   Metropolitan Water  District of Southern California,  memorandum,
     October 31, 1977.

 8.   Dorway-Worley,  Pam, "Hercules  City  Council Was  Faced with a  Critical
     Decision,"  Compost  Science/Land Utilization, May/June 1979,  p.  19.

 9.   Kildow, Judith  and  John  E. Huguenin, Problems and Potentials of
     Recycling Wastes for Aquaculture, Cambridge, Massachusetts:
     Massachusetts  Institute  of Technology, December 30,  1974,  pp.  96-97.

10.   See:   Nieman,  Thomas J., "Water Reuse and  the Professionals,"  in
     Water Reuse and the Cities, Roger E. and Jeanne X.  Kasperson," eds.
     Hanover, N.H.:   The University Press of New England, 1977, pp.  143-165.

11.   Carley, Robert  Lane, Wastewater Reuse and  Public  Opinion,  Master's
     Thesis, University  of  Colorado, Department of Civil and Environmental
     Engineering, 1972.

12.   Personal conversations with Pam Dorway-Worley,  August 1979.

13.   See:   Chatland, Harold,  A Technique to Assist Citizen Groups in
     Decision Making. National  Science Foundation, n.d.,; and  Institute
     for Participatory Planning, Citizen Participation Handbook for
     Public Officials and Other Professionals  Serving  the Public,
     Laramie, Wyoming:   IPP,  1978.
                                     473

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         The reader may also wish to consult:

In the study of public attitudes, William H. Bruvold, of the
School of Public Health, University of California at Berkeley, has
conducted a series of public attitude surveys on the reuse of water:
"Public Attitudes Toward Uses of Reclaimed Wastewater," Water and
Sewage Works, April 1970, pp. 120-122; Public Attitudes Toward Reuse
of Reclaimed Water [n.p.], University of California, Water Resources
Center (Contribution No. 137), August 1972; and "Using Reclaimed
Water:  Public Attitudes and Governmental Policy," Public Affairs
Report, 17:3, June 1976, Bulletin of the Institute of Governmental
Studies, University of California, Berkeley.  Other surveys include:
John Sims and Duane Baumann, "Renovated Waste Water:  The Question of
Public Acceptance," and Duane Baumann, "Public Acceptance of.Renovated
Wastewater—Myth and Reality," Water Resources Research, 10:4, August
1974, pp. 659-665, and pp. 667-674 respectively; and Ralph Stone and
Company, Inc., Wastewater Reclamation:  Socio-Economics, Technology,
and Public Acceptance, Los Angeles:  1974, Chapters II-V.

         Some interesting political patterns are examined in:

Helen M. Ingrain, Patterns of Politics in Water Resource Development:
A Case Study of New Mexico's Role in the Colorado River Basin Bill.
Albuquerque:  University of New Mexico, Institute for Social Research
and Development, Decmeber 1969; and Dean E. Mann, Water Policy and
Decision-Making in the Colorado River Basin [n.p.], Lake Powell
Research Project Bulletin No. 24, July 1976.
                             474

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     ECONOMICS OF AQUATIC  TREATMENT  SYSTEMS

     Ronald W. Crites,  Project Manager,  Metcal f 4 Eddy,
      Sacramento, California 95814
     Aquatic treatment systems use  various  aquatic  plants and animals to
achieve wastewater treatment.   System  types include those using
artificial wetlands, macrophytes (principally water hyacinths),
invertebrates, fish, and integrated (polyculture) combinations of plants
and animals.  These systems,  like land treatment  systems, are
alternatives to conventional  mechanical  facilities  that use  a great deal
more resources (chemicals)  to  treat wastewater.   This  paper  explores the
economics of these aquatic  systems  and compares their  costs  with those
of land treatment and conventional  treatment.  Design  conditions and
land costs will be varied to  ascertain the  importance  of these
parameters in overall costs.


DESIGN CRITERIA

     The criteria that principally  affect capital  costs in  aquatic
systems are hydraulic detention time and depth of water in  the pond or
wetlands.  Reported values of these parameters and  resultant area
requirements are presented in Table 1.  The reported range  is very wide
because it includes some combinations of oxidation ponds with the
aquatic treatment systems.   The values listed in  Column 2 are typical of
the recent literature on artificial wetlands [1], water hyacinths [2],
and polyculture [3, 4], and will be used later in this paper for the
cost comparisons.  There are too few experimental  systems using  fin fish
to allow specific design criteria to be set.
                                      475

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         Table 1.  DESIGN CRITERIA FOR AQUATIC TREATMENT SYSTEMS


                    Type of system     Reported range Values used
Artificial wetlands
Detention time, days
Depth, ft
Area, acres/mgd
Water hyacinths
Detention time, days
Depth, ft
Area, acres/mgd
Fin fish ponds
Detention time, days
Depth, ft
Area, acres/mgd
Polyculture
Detention time, days
Depth, ft
Area, acres/mgd

2-25
0.5-3
10-130

4-60
1.5-5
2-40

5-60
2-10
3-40

4-15
4-10
1.5-7.5

10,
1.
20,

5,
3
5,

_.
._
—

10
6
5

20
5
40

10

10








Artificial Wetlands

     Artificial wetlands are distinguished from natural wetlands because
of the capital cost of constructing a shallow pond or marsh.  Small
reported on a constructed marsh-pond system for treatment of various
wastewaters and recommended 12 to 15 days of detention time for treating
raw wastewater [1].  De Jong reported 96* removal  of BOD at detention
times of 10 to 16 days in wetlands containing rushes and reeds [5].
     Kadlec indicated that the detention time for natural wetlands may
be considerably longer than for artificial wetlands and that the natural
systems may have area requirements of about 50 acres/mgd [6].  The
natural wetlands projects usually function year-round in areas as far
north as Wisconsin, Michigan, and Minnesota.

Water Hyacinths

     Several researchers have reported on the use of water hyacinths for
wastewater treatment including Wolverton [2], Dinges [7, 8], and
Cornwell [9].  Systems designed for secondary treatment typically have
detention times of 5 to 10 days and depths of 3 to 4 feet.
     The area requirements for hyacinth ponds can Increase if winter
storage is required.  Most projects to date have been located in
Florida, Mississippi, and Texas.  Water hyacinths cease to grow when
water temperature is about 40°C or below 10°C, and hyacinths are killed
when the tip of the rhizome becomes frozen [10].  Consequently, winter
storage or alternative macrophytes are necessary where winter water
temperatures drop below 10°C.
                              476

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     Another factor affecting  the  cost  of  hyacinth  systems  is harvesting
and use or disposal.  For systems  designed  for  secondary  treatment,  it
is assumed that harvesting will  be limited  annually to  10 dry tons/acre.
This practice seems necessary  to maintain  some  open water in the pond
and to keep the hyacinths growing.  Higher  harvesting rates in Florida
are designed to remove the nutrients contained  in the hyacinths [11].
     Another aspect of possible  economic interest is the  ability of
water hyacinths to transpire water at a rate  higher than  lake
evaporation.  This phenomenon  has  been  measured at  between  1.5 and 3
times lake evaporation [12, 13].   Where the effluent level  of TDS or
salinity is of concern, other  plants such  as  duckweed could be
considered or the potential for  covering the  system could be
investigated.

Fin Fish

     Stowell et al. listed blackfish, carp, tllapia, catfish, mosquito
fish, and white amur as fin fish that could be  used in  wastewater
aquaculture [14].  Coleman et  al .  reported  on an experimental system at
9uail  Creek in which channel catfish, golden  shiners, and tilapia were
introduced [15].  Despite predation of  the  golden shiners by black
bullhead already present in the  lagoon, the system  reduced  the suspended
solids effluent concentration  to 12 mg/L.   Detention time in the six-
cell pond system totalled 70 days with  half of  the  ponds  containing
fish.

Polyculture

     Although most aquatic treatment systems  could  be called
polyculture, this term is applied  here  to  integrated, planned systems
involving plants, fish, bivalves, or crustaceans.   Dinges tested a 5-
step polyculture system with a detention time of 5  days [3].   The ponds
varied in depth from 2 to 8 feet, but the  treatment performance was
quite high, as shown in Table  2.

            Table 2.  PERFORMANCE OF A  FIVE-STEP POLYCULTURE
                       SYSTEM  OVER FIVE MONTHS  [3]

         Wastewater constituent     Influent. mg/L  Effluent, mg/L   Reduction, X
       BOD2o. mg/L                   90          18           76
       TSS, mg/L                     35           7           80

       Organic nitrogen, mg/L            4.8          1.2         75

       Ammonia. mg/L                   2.1          0.1         95
       Fecal col i forms, No. /100 mL     1,400          10           99
                                      477

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COST  OF  AQUATIC  SYSTEMS

      Very  little information on costs is available in the literature.
In  1976, Henderson and Wert compared 15 strategies involving
conventional  and aquatic  treatment systems [16].  At a flow of 0.2 mgd,
the cost-effective strategy for secondary treatment was the addition of
an  aquatic  treatment  system to an oxidation pond.  No strategies were
found to reduce  nitrogen  below 3 mg/L.   They also found that the
economic return  from  aquaculture products was not critical to their cost
effectiveness.

Basis of Costs

      Costs  of water hyacinth treatment, artificial  wetlands, and
polyculture,  in  conjunction with oxidation ponds and land treatment, are
compared based on  March 1978 costs.   The basis of the conventional and
land  treatment costs  is presented in Crites et al.  [17].   The major
elements are  summarized in  Table 3.

                    Table  3.   BASIS OF COST COMPARISONS
                          EPA STP index      290.1
                          Date of comparison  March 1978
                          ENR CC index       2693
                          Power cost, t/kWh   4.6
                          Labor, $/hr        8.35
                          EPA O&M index      1.67


Land Costs

     Land costs were included at $4,000/acre  and  at $10,000/acre.  Land
appreciates at 3% per year according  to the EPA cost-effectiveness
guidelines.  The area requirements  for  the treatment systems are
summarized in Table 4.  The multiple  listings  of  areas  represent two
different conditions.

                       Table 4.  LAND REQUIREMENTS
                           System                Area, acres/mgd
Conventional, aerated lagoons, and AWT
Oxidation ponds
Hyacinth ponds
Artificial wetlands
Polyculture
Rapid infiltration
Overland flow
Slow rate
1
18,
5,
20,
5
20
60
160

30
10
40




                              478

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Advanced  Secondary Treatment

     Costs of  1-mgd advanced secondary  treatment systems were estimated
using data from the EPA updated report  on Costs of Wastewater Treatment
by Land Application [18] and from Crites  et al. [17].  Advanced
secondary treatment is defined as BOD and suspended solids of 10  mg/L
and fecal coliforms of 200 MPN/100 ml.

     Water Hyacinth Ponds.  A treatment system  consisting of preliminary
screening and  grit removal, oxidation ponds, and water hyacinth ponds
was evaluated  under two different conditions.  These conditions are
described in Table 5.  The climate must be moderate to allow water
hyacinths to survive in the winter.  The  harvested hyacinths are  assumed
to be composted and sold or given away.   The costs of advanced secondary
treatment using the conditions in Table 5 are presented in Table  6. As
indicated in the table, the less favorable conditions nearly double the
treatment costs and the principal effect  is in  the capital costs.   The
cost of the land increases from 3% of the total cost to 7* under  the
less favorable conditions.  Harvesting  costs at $10 to $20 per dry ton
have a negligible effect on overall  costs.

                Table 5.  CONDITIONS  FOR A 1-mgd ADVANCED
                  SECONDARY SYSTEM USING WATER HYACINTHS
                                             Conditions
                     Factor             Favorable  Less favorable
Oxidation pond area, acres3
Hyacinth pond area, acres
Wastewater pumping head, ft
Piping to site, miles
Land cost, $/acre
Harvesting cost, $/acre
Return on compost, I/acre
18
5
150
1.5
4,000
100
50
30
10
150
5
10,000
200
0
                a.  Based on 5-ft deep ponds with detention times of
                   30 days for favorable conditions and 50 days for
                   less favorable conditions.
          Table 6.   COSTS OF A 1-mgd  ADVANCED SECONDARY SYSTEM
                           USING WATER HYACINTHS

                                                 Conditions
                                           Favorable  Less favorable
            Capital cost, $/gal of capacity           1.15        2.21

            Capital cost (amortized), (/I,000 gal     26.6        46.4

            DIM cost, t/1,000 gal                  16.9        22.5
            Land cost, 
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     Artificial Wetlands.  A flowsheet similar to the one for water
 hyacinths was also evaluated.  This  flowsheet contained an artificial
 wetlands following the oxidation ponds with favorable and less favorable
 conditions described  in Table 7.  The climate is not restricted to
 moderate and no return was assumed for the harvested plants.  The costs
 of a 1-mgd system are presented in Table 8.

           Table 7.   CONDITIONS FOR  A 1-mgd ADVANCED SECONDARY
                    SYSTEM USING ARTIFICIAL WETLANDS
                                            Conditions
                                       Favorable Less favorable
Oxidation pond area, acres
Wetlands area, acres
Piping to site, miles
Land cost, $/acre
Harvesting cost, $/acre
18
20
1.5
4,000
'50
30
40
5
10,000
200
          Table 8.  COSTS OF A 1-mgd ADVANCED SECONDARY SYSTEM
                        USING ARTIFICIAL WETLANDS
Conditions
Favorable Less favorable
Capital cost, $/gal of capacity
Capital cost (amortized), 
-------
and for less favorable conditions it is 57* of conventional  treatment.
Keeping all other conditions (in the less favorable column)  constant,
the price of land could be $115,000/acre before the conventional  system
would be equal  in cost to the oxidation pond plus water hyacinth  system,

      Table 9.   COST COMPARISON OF 1-mgd ADVANCED SECONDARY  SYSTEMS
                               */l,000 gal
                                             Conditions
                  Treatment system          Favorable Less favorable
Oxidation pond plus hyacinths
Oxidation pond plus wetlands
Overland flow
Conventional
130
50
96
130
74
90
115
130
Advanced Wastewater Treatment

     Two flowsheets were developed to meet advanced wastewater treatment
(AWT) standards using land and aquatic treatment processes.  AWT is
defined in this case to be advanced secondary plus nutrient removal.
The effluent requirements are total nitrogen less than 3 mg/L and total
phosphorus less than 1 mg/L.  These standards exist only in a few areas
of the United States and may not be applied, widely.  It is important to
compare costs of achieving these standards by various means, however,
and to compare nutrient removal costs with those of advanced secondary
treatment.

     Polyculture Plus Rapid Infiltration.  A promising flowsheet for AWT
consists of preliminary screening and grit removal, oxidation ponds,
polyculture (without aeration), and rapid infiltration.  The assumptions
for oxidation ponds, land, and piping to the site are the same as for
the favorable conditions under advanced secondary treatment.  For
polyculture, a multiple-cell, 10-day detention time system patterned
after Dinges [3] was developed.  The average depth is 6 feet and the
area needed is 5 acres.  No aeration or pond covering is provided, which
1s different than the polyculture system of Serfling [19].
     The polyculture system should produce an effluent low in BOD,
suspended solids, and nitrogen.  The rapid infiltration system will
provide additional removals of these constituents and will remove
phosphorus down to less than 1 mg/L.

     Overland Flow Plus Hyacinths.  This combination of treatment
processes could be very attractive for small- to medium-sized
communities particularly in the southeast.  The system consists of
preliminary screening and grit removal, chemical addition, overland
flow, and water hyacinth ponds.  As practiced by Peters and Lee, the
addition of alum (or ferric chloride) to the screened wastewater ahead
                                      481

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of overland  flow will precipitate phosphorus  on the overland flow slopes
[20].   Overland flow will remove BOD and  nitrogen to the required
levels.   The hyacinth ponds provide further removals of BOD, suspended
solids,  and  nitrogen.

     Cost Comparison.  The comparative costs  for these two flowsheets
and for slow rate land treatment and AWT  are  presented in Table 10.  The
capital  costs are presented in units of $/gal  of design capacity.  The
slow rate system requires 160 acres of land compared to 43 acres for the
polyculture-rapid infiltration flowsheet  and  70 acres for the overland
flow-hyacinth system.  The AWT system consists of activated sludge,
chemical  precipitation of phosphorus, and  filtration plus nitrification
and denitrification for nitrogen removal.

                    Table 10.  COST COMPARISON OF 1-mgd
                         NUTRIENT REMOVAL SYSTEMS

                                            Capital cost,   Total cost,
                 Treatment system            $/gal of capacity  $/l,000 gal

            Oxidation pond plus polyculture
            plus rapid infiltration                 1.32           51
            Overland flow plus water hyacinths        1.81           79
            Slow rate land treatment                3.44          110
            AWT                                6.28          240
      In Table  10,  the costs are representative of  favorable conditions
for all flowsheets including land cost at $4,000/acre.   For the 1-mgd
system, the  system with the lowest costs is the oxidation  pond,
polyculture, rapid infiltration flowsheet, which is  21%  of the AWT cost.
Many  other flowsheets could be developed that would  have lower capital
cost  than the  AWT  system selected and it is doubtful  that  at 1  mgd the
AWT system,  costing over $6 per gallon of capacity,  would  be affordable.

      Land Cost Sensitivity.  All four flowsheets were retained for
comparison of  costs at 10 mgd.  The total costs of the systems are
compared for land  costs of $4,000 and $10,000/acre in Table 11.  The
slow  rate system with the most land increases in cost by 38%;  however,
the costs of the two aquatic-land treatment systems  only increase by 16%.

                   Table 11.  COST COMPARISON OF 10-mgd
                         NUTRIENT REMOVAL SYSTEMS
                                */l,000 gal

             Treatment system            Land * $4,000/acre  Land « $10,000/acre

        Oxidation pond plus polyculture
        plus rapid infiltration                 24              28
        Overland flow plus water hyacinths        37              43
        Slow rate land treatment                63              87
        AWT                                 110             110
                               482

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SUMMARY AND CONCLUSIONS

     Aquatic treatment systems,  although  still  in  the development stage
in most areas, offer low-cost,  low-energy solutions for wastewater
treatment.  For advanced secondary treatment  {BOD  and suspended solids,
10 mg/L; no nutrient removal),  combinations of  oxidation ponds with
water hyacinths or wetlands are cost effective  compared at 1 rogd with
land treatment or conventional  treatment. For  the lowest cost flowsheet
examined, the land cost can reach  5115,000/acre before the conventional
activated sludge system becomes economically  competitive.
     For advanced wastewater treatment (nitrogen,  3 mg/L; phosphorus, 1
mg/L), aquatic systems alone have  not been developed technically to
achieve the same standards.  The aquatic  processes can, however, be
integrated with land treatment  and oxidation  ponds to achieve this high
quality of effluent.  In the cases studied, the combined aquatic-land
treatment systems were less expensive than land or conventional
treatment at 1 and 10 mgd.   As  aquatic systems  become further developed
and demonstrated, the costs will become more  firmly established.  In
addition, the economic benefits (such as  from compost, fertilizer, soil
conditioners, or biogas) may offset some  of the costs of wastewater
treatment in the future.

REFERENCES

1.   Small, M.M,  Wetlands  Wastewater Treatment Systems.  Proceedings of
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     2, pp 141-147.  August 1979.

2.   Wolverton, B.C. and R.C. McDonald.  Upgrading Facultative Waste
     Stabilization Ponds with Vascular Aquatic  Plants.  Journal WPCF.
     Vol. 51, No. 2, pp 305-313.  February 1979.

3.   Dinges, R.  A Proposed Integrated Biological  Wastewater Treatment
     System.  In;  Biological Control of  Water  Pollution.  Tourbier, J.
     and R.w. Pierson, Jr.  {ed.).   University of  Pennsylvania Press, pp
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4.   Golueke, C.G.  Aquaculture in Resource  Recovery.  Compost
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5.   De Jong, J.  The Purification of Wastewater  with the Aid of Rush or
     Reed Ponds.  In:  Biological  Control of  Water Pollution.  Tourbier,
     J. and R.W. Pierson, Jr. (ed.).  University  of  Pennsylvania Press,
     pp 133-139.  1976.

6.   Kadlec, R.H,  Research Results for Engineering  Design  of  the
     Wetlands Treatment System, Houghton, Lake  Michigan.  Presented  at
     the Seminar on Aquaculture Systems for Wastewater Treatment.
     University of California,  Davis.  September  1979.
                                      483

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 7.   Dinges, R.   Upgrading Stabilization Pond  Effluent by Water Hyacinth
      Culture.  Journal  WPCF.   Vol.  50,  No.  5,  pp  833-845.  1978.

 8.   Dinges, R.   Development  of Hyacinth Wastewater Treatment Systems in
      Texas.  Presented  at the Seminar on Aquaculture  Systems for
      Wastewater Treatment. University of California, Davis.  September
      1979.

 9.   Cornwell, D.A., et al.  Nutrient Removal  by  Water Hyacinths.
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10.   Bagnall, L.O., et  al. Feed and Fiber  from Effluent-Grown Water
      Hyacinth.  In:  Wastewater Use in the  Production of Food and Fiber,
      EPA-660/2-74-041.   pp 115-141.   June 1974.

11.   Stewart, E.A. III.  Water Hyacinths for Advanced Wastewater
      Treatment - Trickling Filter Plants.  Presented at the Seminar on
      Aquaculture Systems for  Wastewater Treatment.  University of
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12.   Van Der Weert, R.  and G.E.  Kamerling.  Evapotranspiration of Water
      Hyacinth.  Journal of Hydrology.  Vol. 22, pp 201-212.  1974.

13.   Benton, A.R., Jr., et al.  Evapotranspiration from Water Hyacinth
      in Texas Reservoirs.   Water Resources  Bulletin.  Vol. 14, No. 4, pp
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14.   Stowell, R., et al.  The Use of Aquatic Plants and Animals for the
      Treatment of Wastewater.   Department of Civil Engineering,
      University of California, Davis.  September  1979.

15.   Coleman, M.S., et  al. Aquaculture as  a Means to Achieve Effluent
      Standards.   In: Wastewater Use in the Production of Food and
      Fiber.  EPA-600/2-74-041.  pp 199-214.  June 1974.

16.   Henderson,  U.B. and F.S.  Wert.   Economic  Assessment of Wastewater
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      Office of Research and Development. EPA-600/2-76-293.  December
      1976.

17.   Crites, R.W., M.J. Dean,  and H.L.  Selznick.  Land Treatment vs. AWT
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18.   Reed, S.C., et al.  Costs of Land Treatment  Systems.  Environmental
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                                    484

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19.   Serf ling, S.A.  and D.  Mendola.  The  Solar Aquacell AWT Lagoon
      System for the  City of Hercules, California.  Proceedings of the
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20.   Peters, R.E. and C.R.  Lee.   Field  Investigations of Advanced
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                                     485

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