LAND APPLICATION OF
          WASTEWATER IN
             AUSTRALIA


      The Werribee Farm System

 Melborne and Metropolitan Board of Works
            Victoria, Australia

                   by
         BELFORD  L. SEABROOK
          Professional Engineer
              MAY 1975
US ENVIRONMENTAL  PROTECTION AGENCY
      Municipal Construction Division
    Office of Water Program Operations
         Washington,  D.C. 20460

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ABBREVIATIONS

    Board   -   MMBW-Melbourne and Metropolitan Board of Works
    BOD    -   biochemical oxygen demand
    cm      -   centimeter
    COD    -   chemical oxygen demand
    Farm   -   Werribee Farm soil treatment system of MMBW
    in.      -   inch
    MMBW  -   Melbourne and Metropolitan Board of Works
    N       -   nitrogen
    mgd     -   million gallons per day
    mg/1    -   milligrams per litter
    ppm     -   parts per million
    P       -   phosphorus
    SS      -   suspended solids
TERMS

    Conventional secondary treatment - Reduction of pollutant concen-
    trations in waste-water by physical,  chemical or biological menas.

    Crop irrigation - Application on  land of water to meet the growth
    needs of plants.

    Evapotranspiration - The unit amount of water used on a given area
    in transpiration, building of plant tissue, and  evaporated from ad-
    jacent soil, snow, or  intercepted precipitation in any specified time.

    Grass filtration - Same as overland flow.

    Land application or Land Treatment - The  discharge of wastewater
    onto the soil for treatment,  reuse or crop irrigation.

    Overland flow  - Wastewater treatment by grass filtration,  flooding
    or spray-runoff, in which wastewater is applied onto gently sloping,
    relatively impermeable soil which has been planted to vegetation.
    Biological oxidation occurs as the wastewater flows over the ground
    and makes contact with the biota in the vegetative litter.

    Raw sewage -  Untreated wastewater.

    Secondary treatment  - Something more  than primary treatment,
    usually treatment by physical, chemical, or biological means such
    as trickling filters, activated sludge, or chemical precipitation
    and filtration.  Sometimes called mechanical treatment.

CONVERSIONS

    1 Acre feet  =   3, 060, 000  US gallons,  or 2, 550, 000 Imperial gallons
    A$          =   Australian dollars
    A$l. 00      -   US $1. 35
    US$1.00     =   A$0.74-    ,-.    ~r
                                  J.  0*317

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  WESTEN

           /
CATCHMENT

         r--*
          •OAMOt
           rum
        ^
DANDENONG'7
                                                  VALLEY
                                MELBOURNE
                                        .EASTERN
                                       \TCHMENTV
                  \
                                                          HMENT ^
                                                                    5
                       PORT PHILLIP BAY
              MELBOURNE AND  METROPOLITAN AREA


                            - 2 -

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SUMMARY




    This report concerns the Werribee Farm soil treatment




area operated by the Melbourne and Metropolitan Board of Works




(MMBW).  The Board (MMBW) was constituted in 1890 by an Act



of the Parliment  of  Victoria to develop and operate a system of




main and general sewerage for the metropolis.  James Mansergh,




an eminent sanitation engineer from London,  submitted eight al-




ternative schemes, five of which involved treatment by land; two,




disposal by ocean outfall; and  one,  by chemical precipitation.




Mansergh stated that the Werribee site was situated for land puri-




fication  of sewage because it was exceptionally  dry and had  an




abnormally low rainfall compared with surrounding districts. His




recommendation, based on proven success  in England, and on the




benefit  of irrigation in an area of low rainfall, was for disposal




by flood irrigation on prepared land  without prior  treatment of



the sewage.    Even today raw  sewage  is used at the Werribee




Farm.  Work began in 1892; and in  1897, the sewage from the




first property (a hotel) was delivered to the system.   Mansergh,




of course, could  not have foreseen Melbourne's rapid population




growth nor the demands that would be  placed on the Werribee




Farm within  30  years of its establishment.  By the late  1930's,



the heavy waste  loadings had made it necessary  to not only en-




large the area of the Farm, but also to complement land filtration




(called  crop irrigation in the United States) with sedimentation,
                              -3-

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grass filtration (overland flow) and lagooning.  Despite these ad-



ditions to the Farm's land treatment operations, the 1897 system



remains,  to this day, basically as it was originally conceived



and build.  Even the introduction of the South-Eastern Sewerage



System (in 1974) on the  opposite side of Port Phillip Bay fulfills



Mansergh's original concept of a  disposal system serving each



side of the Bay.   The relationship of the Werribee Farm to the



South-Eastern Sewerage  System can be seen on the accompanying



map of the Melbourne Metropolitan area.  In June 1974, there were



some 800, 000 ratepayers (population 1, 880, 000) being served by



the Board.   The Werribee  Farm serves about 95  percent of the



sewered areas in the metropolis.   The balance is served by four



other major and two minor systems.



    For the fiscal year ending June 1974,  the annual per capita



cost of  the  Board's Werribee  system was  A$1.13 (US$1. 53) for



95 percent of the population of 1, 880, 000.  This figure includes



all current  costs.  The  capital costs of the land and the original



construction were written off years ago.  The average daily flow



to the Werribee  Farm, is  125 million British Imperial gallons



(150 mgd US).



    The principal problem with land treatment at MMBW is caused



by the increasing hydraulic load per capita coupled with the in-



creasing population served by the  system.
                              -4-

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    Because the cost of purification at Werribee is substantially less




than by mechanical  treatment,  as well as because the  quality of the



effluent from  Werribee is  higher,  the MMBW intends to continue to



utilize land treatment to the extent possible.   However,  as the popu-



lations of Melbourne and Geelong increase, and the urban areas extend



outward toward the  Werribee Farm, the acquisition of  additional land



adjacent to Werribee has not been possible. As a consequence, MMBW



is constructing conventional secondary mechanical  treatment works and



plans to  transfer about 45% of the hydrological load from the Werribee



Farm  to the  new  South East  mechanical system.  In  spite of this,



by 1980/81 the MMBW estimates  that the pollutant loading will  return



to the maximum that the Werribee Farm, as presently operated,  can



handle.



    Currently  all sewage to the Werribee Farm is raw sewage. This



has been the practice since land treatment was started in 1897. How-



ever, in order to provide increased treatment capacity at Werribee,



MMBW is giving consideration to using a combination of part primary



to full secondary treatment in  conjunction with biological processes.



    In summary,  the MMBW  Werribee system is in full operation, is



most successful, is substantially  lower in  annual per capita cost of



operations,  and MMBW intends to continue to operate its land treat-



ment facilities indefinitely.

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LAND TREATMENT IN UNITED STATES



    The Federal Water Pollution Control  Act Amendments of 1972



(Public  Law  92-500),  the legislative history  of the Act, and the



regulations  which have  been issused in accordance  with the pro-



visions  of the  Act, provide  the statutory basis for consideration



and funding  of land-application systems in the treatment of municipal



wastewater.



    The rationale  and goals  within which land-application systems



are to be considered are contained in the following sections of the



Act:



    Section 208  -  Areawide Waste Treatment Management



    Section 201  -  Facilities Planning



    Section  304 -  Best Practicable  Treatment Technology  (BPT)



    Section 212  -  Cost Effectiveness Analysis



These sections, together with  the regulations pertaining to  these



sections of the Act, and the Program Memoranda to the EPA Regional



Administrators, have resulted in a growing interest in the United



States in soil treatment  systems  for municipal wastewater.  The



EPA Deputy Administrator,  on November  1,   1974,  wrote to the



Regional Administrators urging  them  to  ascertain that the regional



review of application for construction of publicly-owned treatment



works requires that land application  of  wastewater be considered



as  an alternative waste management  system.  The DA  said that the



RA's  should refuse to fund projects using other systems of waste



treatment if it  can be demonstrated that land treatment is the most
                                  -6-

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cost-effective alternative; is consistent with the environmental



assessment; and, in other aspects,  satisfies applicable  tests.



This memorandum is attached hereto.



    In addition to the potential for being the most cost effective



treatment alternative (note the MMBW total annual per capita cost



for the fiscal year ending June 1974 is US$1. 53 for sewage treat-



ment serving 95 percent of the population of 1. 88 million people),



another significant reason for the growing interest in land treat-



ment is that PL  92-500  gives authority to the EPA Construction



Grants Program  to  fund publicly-owned soil treatment systems



including  the acquisition of the  land that will be  an integral part



of the  treatment process --  Section 212(2)(A).



    The EPA report, entitled,  Survey of  Facilities Using Land



Application of Wastewater by American Public Works Association,



identifies certain existing soil treatment systems that were started



in the United States as early as 1880. However, these early systems



started as disposal projects, and there is  a major gap in reliable



design data and information. The consequences  of this dearth of



design information has handicapped the  construction grants pro-



gram, primarily  because of the lack of standard criteria.  Another



deterrent has been  the  lack of  information  concerning potential



health hazards from soil treatment systems.
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    Strangely, however, the same dearth of information concerning




potential health hazards from secondary  treatment and discharge




to surface  waters has not slowed the demand for the more costly




conventional reinforced concrete treatment works.  In fact, it seems




to me that  there could be far greater health hazards from secondary




discharge into surface waters because these waters are so often used




as sources of potable water by  other  downstream municipalities.






INTRODUCTION




    There are 17 residences located in the midst of the  Werribee




Farm which are used by farm employees and their families.  I visited




several  of the homes of fa.rm  employees,  met members of their




families inchiding the children, and enjoyed a Sunday picnic on the




front lawn of one of these residences.  There is no evidence of health




hazards  caused by sewage irrigation in the adjacent fields, and no




concern  was expressed by  the occupants of these houses about po-




tential health hazards.   To the foreign observer  that I  was, these




residences appeared no different than any other  farm residences,




and their occupants appeared no different than any other farm families,




either in Australia or in the United States.  Incidentally, on previous




trips to  Australia  I  visited  many  rural communities  in every




Australian state,  except the  Northern Territory,  and  I lived and




worked onfarms in the United States over a period of several decades.
                              -8-

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In my judgment, the farm houses located on the Werribee



Farm are  better  than  the majority of farm  dwellings  in  the



United States, and the occupants are living under better  health



conditions  than some of their  counterparts in  both  Australia



and the U.  S.



    The Werribee Farm soil treatment system is the outstanding



project in  Australia  from the standpoints of the lowest  annual



operating costs, success,  size and extent of experience with the



use of wastewater effluents.  The map of Melbourne on page 2



shows the  relationship  of the Board's Werribee Farm to Port



Phillip Bay and the  surrounding  Melbourne and Metropolitan



areas.  The South-Eastern Purification Plant (secondary treat-



ment) is also shown on  this map.



    The Farm has  served the residents  of Melbourne as a re-



liable and economical means of  wastewater treatment and utiliza-



tion since 1897. The use of wastewater for irrigation of pasture



land,  and the  subsequent production of  cattle and  sheep, is an



outstanding example of reclamation and conservation.  Over the



years, however, population and industry have increased greatly.



As  a result,  the Farm is no longer able to cope satisfactorily



with the volumetric and organic loadings imposed upon it.
                            -9-

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LIVESTOCK AND THE TREATMENT PROCESS



    The livestock at the Farm are  not  only money-earners from, the



point of view of meat, they are also an essential part of the treatment



operations.



    Because wastewater treated at the Farm contains a high proportion



of natural fertilizers, it  promotes a prolific growth  of pasture; but



since crop irrigation is an efficient  method only if the vegetation cover



is kept short, cattle and sheep are effectively used to "mow"the grass.



    Sheep were introduced to the Farm in 1900 and cattle some 10 years



later.   In the years since,  the Board has sold more than 1.7 million



sheep and well over a quarter million  head of beef cattle from its



Angus and Hereford herds.



    Grazing of  sheep is on a  seasonal  basis, and the Board buys the



animals in various parts of the  southeastern corner of Australia to fatten



them for market.   The beef cattle, on the other hand, are bred on the



Farm and remain the re until they are ready for sale.  The most suitable



animals are retained for breeding  and the others are  sold as prime



meat on the hoof at Newmarket, Melbourne.



    Sales of cattle are subject to the  condition that they must be immed-



iately slaughtered at an abattoir in the Melbourne metropolitan area,



and those killed must undergo rigid inspection.  This condition,  imposed



in the 1920's by the Parliament  of Victoria, was a political one obtained



by the commercial  beef producers and had no health hazard basis.
                              -10-

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    Diversion to the South Eastern Purification Plant of a portion of the



wastewater now reaching the Farm will ease, but not solve, the situation



for a number of years, but continued growth in the Western Catchment



will produce flows and loadings well in excess of those at present.  For



example,  the loading of biochemical oxygen  demand  will total  about



750, 000 pounds per day before completion of the South Eastern Purifi-



cation Plant; diversion to that plant will remove slightly over 100, 000



pounds per day; increased development  in the Western Catchment will



gain this amount back before 1985; and, less than fifty years hence,  the



total loading may exceed 1, 000, 000 pounds per day.



    The Farm system serves about 95 percent of the sewered areas in



the metropolis.  Except for wastes from the greater part of the Munici-



pality of Sunshine, which are discharged directly in the Main Outfall



Sewer, and from Williamstown,  which enter the main system at Spots-



wood, all  wastes collected by the Farm system flow by gravity through



two main  sewers - the North Yarra and the Hobsons Bay Main Sewers



which unite at Spots wood.



    The combined flow then continues  for 21/4 miles  via a 9 ft.  3 in.



diameter trunk sewer which terminates at the Brooklyn pumping station.



Flows in  this sewer  enter the pumping station through two penstocks,



or control gates,  set at the bottom of a well, 144 ft.  deep and 22 ft.



in diameter.  The penstocks control the flow into each of two protective



screen wells, 156 ft.  deep and 22 ft. in diameter.
                               -11-

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    From each screen well,  the  flow  continues to its  corresponding
pump well.
    The two pump wells  are each 178 ft. deep  (internal) and 66 ft. in
diameter.  Four pumps are installed in each well, and the eight pumps
are driven by individual  electric motors, the combined rating of which
totals 12,800  horsepower.   Each pump has a maximum  capacity of
42 mgd (50 mgd,  US).
    When Melbourne's sewerage scheme was originally designed, Port
Phillip  Bay was  selected as the most suitable body of water for the
final disposal of the effluents after purification.
    The most  suitable method of purification known in European coun-
tries at the time was land treatment, and the  site chosen near Werribee,
between the  Geelong  Road and Port Phillip Bay,  possessed  all the
factors essential for the satisfactory operation of the method--ample
area, reasonable isolation,  suitable soil and climatic conditions.
    An area of 8, 847 acres was acquired,  and the preparatory work
began in 1893. As  the city has grown, it has been necessary to expand
the Farm area,  and today it covers 27, 000 acres or nearly 42 square
miles.
    The Board's Farm at Werribee begain operating in 1897.  By 1900,
it handled a wastewater flow averaging 12 million gallons per day (14.4
mgd,  US).    Since that time, the flow has increased  as  a result of
growth of population and industry in the metropolitan area,  and at present,
averages about 125 mgd (150  mgd,  US or 568,650 cubic meters). The
mode of operation,  originally begun  as irrigation of 6,000 acres of
                               -12-

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land to produce pasturage  for  cattle and  sheep,  has  been expanded



over the years to include all-year use of anaerobic  and aerobic lagoons,



sedimentation  basins  and open sludge  digestion lagoons, as well  as



overland flow  (grass filtration) from mid-autumn to mid-spring when



irrigation demands are minimal or nil.



    Rainfall at the Farm averages 19 in. (48. 3 cm. ) annually, of which



about 12. 5 in.  (32. 2 cm. ) of evenly distributed rainfall can be expected



during the  crop irrigation season; whereas, the evapotranspirational



potential during the same period averages about 35.6 in. (90.4 cm. ),



indicating that a major portion  of the annual application of 44 in. (112



cm. ) of sewage effluent has evaporated.  The daily  flows of raw sewage



arriving at the Farm vary greatly depending upon rainfall.  The current



average flow is about 150 mgd (568, 650 cubic meters); however, during



storm periods peak flows as high as 300 mgd (1, 140, 000 cubic meters)



may occur.    Temperature variations are from a low of 40 degrees



F (4.4 degrees  C) in  winter to a high  of 112 degrees  F (44 degrees



C) in summer.








SOIL CHARACTERISTICS
    There is no detailed classification of the Farm soils, but the surface



of the soil profile consists of a red-brown silt clay loam which is slightly



acid.  Clay occurs at a depth of about 12 in.  (30  cm. ).  The depth of



the  clay  subsoil is substantial, extending far below any core samples
                               -13-

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that have been recorded.   The report issued by the U. S. Army Corps



of Engineers in January 1974,  entitled,  "Selected Chemical  Character-



istics of Soils, Forages,  and  Drainage Water  from the Sewage Farm



Serving Melbourne, Australia", contains much detail on soil and forage



characteri stic s.






GENERAL  OBSERVATIONS
    Many aspects of the Farm  operations are  praiseworthy.    Wide-




spread recognition  of the need to conserve or reuse natural  resources




has evolved only in recent years;  however,  since  1910 the  Farm has




reused wastewaterfrom Melbourne for irrigation of pasture land. This




process has  converted land of little potential for agriculture to prime




pasture which now carries over 20, 000 cattle and 10, 000  sheep.  By




using the natural resources,,  water and land, the Farm has marketed




more than  270, 000 cattle and 1, 500, 000 sheep since 1910.  Taking into




account the equipment  and manpower costs related to livestock pro-




duction,  the net returns from sales presently average over A$500, 000



(US$675, 000) per year and significantly reduce the costs directly associ-




ated with sewage purification at the Farm.  Thus,  from conservation




and financial  standpoints,  the  Farm represents a valuable resource




to the residents of Melbourne.



    Initial diversions from the  Farm system  to  the Board's South




Eastern Purification Plant are scheduled for 1975.  Although this will




result in lower loadings  at the  Farm in the short-term,  growth of popu-




lation and industry  tributary to the  Farm will generate additional load-




ings well in excess of those diverted.
                                -14-

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FARM OPERATIONS




    It is logical  to  consider operations  at the Farm from two  stand-




points:     first, in relation to its  primary function for waste-water




treatment  and second,  in terms  of  its use for livestock production.




In addition,  approximately three-fourths of the Farm area is a  de-




clared Wildlife Sanctuary and provides a habitat for a variety of water-




fowl and other birds and animals.








WASTEWATER  TREATMENT




    In the early  years,   treatment at the Farm  consisted of land  fil-




tration  by irrigation of pasture land with the underflow collected in




drainage channels and discharged to  Port Phillip Bay. During winter,




wastewater flows in excess of the  land's capacity were held in shallow




lagoons along the foreshore.   Increasing flows during the intervening




70  years  have  lead to increasing the size of  the Farm from  about




6, 000 acres to nearly  27, 000 acres. Of this total, about 17, 000 acres




are used  for some form of treatment, and  the  balance is devoted to




dry grazing,  roads, buildings, yards, and other purposes.



    The use of grass filtration (overland flow)  during winter months




began about 1928 and made it possible to phase out the shallow lagoons




along the foreshore previously used for winter flows.
                                 -15-

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   Anaerobic and aerobic lagoons were introduced about 1935.  Lagoons

can handle higher loadings of organic matter than either of the two ether

methods of treatment,  and as a result,  their area has  been increased

greatly in recent years to match increases in loadings.  For purposes

of comparison,  numerical values  for the years ending 30 June 1959

and 30 June 1971 are listed in Table A and the monthly variations during

each year are shown on Figures  1 and 2.




      Table A.  Loadings and  Treatment Processes,  1959 and 1971

                                          Year Ending 30 June
                                            1959           1971
Total wastewater volume, milllion
  gallons (US)                               35,160           50,900
Average BODS, milligrams per liter
Pounds per day
Crop irrigation, million gallons (US)
Percent of total
Overland flow, million gallons (US)
Percent of total
Lagoons, million gallons (US)
Percent of total
451
384,000
13, 320
38
13,680
39
8, 160
23
588
661, 000
10,680
21
15, 360
30
24, 960
49
    On arrival at the Farm, the wastewater is distributed to the various

treatment areas through a network of channels.  Three methods of puri-

fication are used.   Short explanations of each method along with perti-

nent comments follow.


                                  -16-

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                                                 -18-

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   Crop Irrigation (land filtration).   This is the primary method which




is used throughout the summer. The land filtration areas are carefully




prepared pastures,  about 20 acres in exent, and  divided into  50 bays




by low check banks. They are subsoiled, graded evenly and sown with




selected pasture grasses.




   The wastewater  is applied as in normal flood irrigation.   Every




18-20 days,  each  block  is covered to a depth of about 4 in.   In all,




about 600 acres are irrigated each day.  The wastewater filters through




the soil and when purified  seeps into deep earth drains.




   The periodic irrigation of pastures with wastes containing a large




proportion of fertilizing  materials promotes a very vigorous growth of




grass.  Rotational grazing by sheep,  cattle and some horses is essential




to maintain these  pastures in a condition suitable  for continued waste-




water purification.




   Application rates for crop irrigation are controlled by the ability of




the soil to absorb water, rather than by the  strength of the wastewater.




Examination of  irrigation  records  from 1935-1971  shows wastewater




irrigation depths  average about 3.  5 feet per year and range  between




2. 9 and 4. 2 feetper year.  In  a given year, the application rate  depends




on the rainfall pattern and  evaporation.  Including annual rainfall, the




land receives more than  5 feet of water depth per year.   Based on




present wastewater strength, the  average application rate amounts




to 30 Ib. of BOD per acre  each day.




   Crop irrigation  is quite effective in reducing the concentrations of




many chemical constituents of concern in terms of their effects on the
                              -19-

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receiving waters.    Compounds of  nitrogen, phosphorous,  and most

of the heavy metals are reduced dramatically.   Table B shows results

of analyses made on the incoming wastewater and the average for effluent

collected from seven  different drainage channels which  pick  up the

underflow from the irrigation areas.
    Table B.  Chemical Characteristics of Untreated Wastewater and
                   Effluent from Crop Irrigation Treatment
                                               T7
                           mg/L Concentrations
Constituent
Organic nitrogen
Ammoniacal nitrogen
Nitrite
Nitrate
Orthophosphate
Total Phosphorous
Sodium
Potassium
Calcium
Magnesium
Copper
Nickel
Chromium
Cadmium
Zinc
Lead
Mercury
Untreated
Wastewater
14.3
35.0
0.75
0
26.2
32. 1
400.0
95.0
65.0
80.0
0.45
0.20
1.0
0.01
1.3
0. 55
0.0015
Effluent
1.0
3.2
1.3
0.4
2.6
2.9
770.0
26.0
45.0
107.0
0.07
0.16
0.09
0.006
0.18
0.12
0.0003
Percent
Removal
93
91
-
90
91
73
30
84
20
90
40
86
78
80
Source:  MMBW Analyses on samples collected 17 May 1972.

I/ Concentrations of nitrogen compounds expressed as N; phosphorous
~~  compounds as PO, ; all other as the particular element.
                              -20-

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    Overland Flow (grass filtration).  This process is used in purifying
the greater part of  the  normal winter flow when reduced evaporation
makes crop irrigation impractical.  In this method,  the wastewater is
first  directed into sedimentation tanks, and when the sludge has settled,
the water is allowed to  flow slowly but continuously over graded areas
on  which Italian rye grass supplements the natural herbage to make
a dense  growth.   The plants act  as a filter in which microorganisms
absorb the organic matter in  the wastewater so  that by the  time it
reaches the drain, it has the required standard of purity.  The overland
flow areas are  grazed only in the  summer when  they are not needed
for purification purposes.
    Detention times are about 2 days.  In contrast with crop irrigation,
loading rates are governed by wastewater strength ratherthan by volume.
Because of the  short detention time, daily loadings rather than long
term  ones are important. Maximum loadings of about 90 Ib. of BOD per
acre each day can be handled.  In practice, however, it is more con-
venient to control application  by  regulating wastewater volume to  the
overland flow areas.  To keep BOD loading rates within the maximum,
the volumetric  rate  of  application of sedimented  wastewater  is held
at about  1 mgd per 50 acres.  Experience at theWerribee Farm indicates
that daily BOD application rates average about 70 Ib. per acre.
    Oxidation  Ponds  Treatment.   This process operates throughout
the year to handle the balance of the normal flows which  cannot be
treated by the other methods and also copes with the wet weather excess
flows.  During this  treatment,  the  wastes flow slowly through large
areas of shallow ponds  where purification is effected by oxygen which
is partly absorbed from the atmosphere and partly provided by algae

in the presence of sunlight.
                                  -21-

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    Oxidation Ponds.   In the  lagoon  treatment process, wastewater



passes through anaerobic lagoons and then  through aerobic lagoons.



Detention times, relatively short in the former and long in the latter,



depend on the rate of wastewater addition,  but generally are  about



one month.  BOD loading rates vary with Wastewater strength and the



volume added.   Experience indicates that  average loading  rates of



about 60  Ib. of BOD per acre  per day can be handled in winter,  while



about 100 Ib. per day can be  handled in summer when photo synthetic



activity is greater due  to higher temperatures and longer  hours of



sunlight.



    Treatment Efficiency. As  shown  by the annual averages  on  Table



C,  the  three treatment processes vary in their ability to remove



organic matter  and other chemical  constituents  in raw wastewater.



The crop irrigation process is the most effective,  but as noted  above,



area loading rates are low and  only about 20  percent of the year's



flow at the  Farm can be treated by this process.  The reductions



it achieves in compounds of nitrogen and phosphorous are particularly



noteworthy.  In raw wastewater given crop irrigation treatment, only



5pounds pass through the top  soil  and are  found in the  effluent.



In contrast,  the comparable  values  for overland flow are 40 pounds



of nitrogen and 65 pounds of phosphorous,  while for lagoons, the



values are  65 and 70  pounds respectively.    In  terms of nitrogen



removal, crop irrigation is 8  times more effective than overland flow



and 13 times more effective than lagoons. Similarly, for phosphorous



removal, it is 13 and 14 times more effective, according to MMBW.
                                  -22-

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    Table C.  Estimated Performance by Treatment Processes
                         on Annual Basis
Characteristics
Percent of total flow
treated
Percent removal
BOD
Suspended solids
Total nitrogen
Total phosphorous
Detergent
E. Coli
Method of Treatment
Crop Irrigation
20


98
97
95
95
80
98
Overland Flow
30


96
95
60
35
50
99. 5
Lagoon System
50


94
87
40
30
30
99.8
    Odors. Sources of odors at the Farm have been studied intensively

several times, particularly in  1950,  1966,  and 1968-1970.  The 1966

work disclosed that the  "odor potential", based on measured hydrogen

sulphide emissions, was four times greater in winter than in summer,

and that sedimentation and sludge digestion basins, lagoons, and over-

land flow  areas were the  principal sources. Crop irrigation areas

and effluent channels were  found to be relatively insignificant sources.

At each of the major sources, the treatment processes are, or are

prone to be,   anaerobic.  Sedimentation and sludge digestion basins

are open,  and hydrogen sulphide and other odorous  gases are readily

released to the atmosphere. The anaerobic  lagoons, an inherent part

of the lagoon  system  presently used, are economic on space due  to

the  high BOD loading which they can  handle,  but  are  the odorous

component.   During winter, the area of anaerobic lagoons is greater

than in  summer, which leads to the release of greater quantities of

hydrogen  sulphide.   In the 1966 tests, this gas was detected over

about half of the area used  for overland flow.
                                -23-

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Livestock Production. Sincel910, the Farm has operated a commercial



beef enterprise, producing  20-22 month  old  steers and fat cull cows



for the  Melbourne market.  During  the past 62 years, over  270,000



cattle have been marketed. Since 1946, almost the entire  cattle output



has been bred and raised on the Farm. In addition,  sheep are brought



in and fattened on the Farm, and during the same period,  more than



1. 5 million have been marketed.



    Early prohibitions against marketing the  cattle for  human con-



sumption because of the incidence of beef measles (cysticercosis)



were overcome in 1946 by the adoption of the carcass inspection and



branding program.  In  addition,  the Farm stock has  built up an im-



munity, and market  rejection for this reason is rare --29 rejections



out of  over 116,000 cattle marketed since 1946.



    In summary, the principal purposes of  operating the Werribee



Farm have been to  renovate  the sewage effluents  and to recover re-



sources that  could  be converted into cash.  Research for the sake



of research alone has not been a major factor, although some elements



of research have been done to seek out solutions to specific problems.



The Werribee  Farm has  31 test  wells for monitoring the  influent



(daily) and the effluent  (twice  weekly) to Port Phillip Bay.



    The Board has some information on soil analyses  at certain loca-



tions.   In  certain small areas affected by salt  accumulation caused



by groundwater,  there is  some information.  There  is  limited data



on receiving water quality,  odors,  and potential  health hazards, as



well as information  on BOD,  SS, COD, pH,  fecal coli,  P,  total N,



nitrate, nitrite and Cl.
                                 -24-

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CORPS OF  ENGINEERS  REPORT



    In May 1972 a team from the U. S. Army Corp of Engineers




made an intensive inspection and study of the Werribee Farm




land treatment system.   An important aspect, among  others,




was to learn as much as possible about long term responses




of the soil/plant ecosystem to sewage applications. Accordingly,




soil and  plant  samples were collected  and  analyzed for their




 nutrient and heavy metal contents.




    A report published by the Corps in January 1974, entitled,




"Selected Chemical Characteristics of Soils,  Forages, and



Drainage  Water  from the  Sewage Farm Serving Melbourne,




Australia",   presents and discusses the findings of this study.




Specifically, data resulting  from the analyses of soil and plant




samples,  from sites under irrigation for periods of 48 to  73




years, is discussed  in  relation  to  a control  sample,  length




of time under irrigation, resultant water quality produced by the




treatment   system,  and expected ranges of constituent concen-



trations  found in soils  and plants  from the literature  on  the



subject.  A  copy of the Corps report is attached hereto.
                            -25-

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MOVIE




    The MMBW has produced a 16mm film, entitled Werribee - In




Harmony with Nature,   showing the land treatment operations at the




Werribee Farm,  This is a nontechnical film,  773 ft.  in length.  Copies




can be purchased from the  MMBW.  EPA has ordered  10  copies of




this film,  one  for each Regional  Office.  Persons wishing  to buy a




copy should address their inquiries to James B.   McPherson, Manager,




Werribee  Farm,  Melbourne and Metropolitan Board  of Works,  625




Little Collins Street,  Melbourne, Victoria 3001,  Australia.
                                 -26-

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                      REFERENCES
1.  Melbourne and Metropolitan Board of Works, Reports, Publicity
      Brochures, Newsletters, Staff Newspaper, Unpublished Memoranda,
      Calculations,  Lists, Fact Sheets, Charts, Sewerage Committee
      Notes, Board of Works Notice Papers, and Interviews with Board
      Officials, Employees and Specialists.

2.  Survey of Facilities Using Land Application of Wastewater, Prepared
      by American Public Works Association, July 1973.  No. EPA-
      430/9-73-006. National Technical Information Service No.
      PB-227-351-A/S.  U. S. Government Printing Office Stock No.
      5501-00666; Cat. No. EP2.2:W28/4.

3.  Article,  Waste into  Wealth,  Water Spectrum  1972.

4.  Report, Program for Development of a Master Plan for Water Quality
      Management at the  Board's Farm, March  1973,  by  Caldwell
      Conn ell Engineers.

5.  Data and statistics from certain  Principal Persons Interviewed.

6.  Data and statistics from Dr. Thomas D.  Hinesly,  University of
      Illinois.

7.  Notes from personal observations during site visits.
                      ATTACHMENTS
1.  Memorandum from EPA Deputy Administrator to RA's,  Nov. 1,  1974.

2.  Report,  U.S. Army Corps of Engineers, January 1974 "Selected
      Chemical Characteristics of Soils, Forages, and Drainage Water
      from the Sewage Farm Serving Melbourne, Australia".
                                -27-

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                 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
SUBJECT:   Land Treatment
DATE:   November 1,  1974
FROM:     Deputy Administrator 1st John Quarles
TO:       Regional Administrators

             The purpose of this  memorandum is to express my concern that
          EPA must do  a better job in assuring  that land treatment  is  given
          full and adequate consideration as a possible method for municipal
          sewage treatment in projects funded with Federal grants.

             Land application of wastewaters is practiced successfully and
          extensively in  the United States.  Many land treatment systems
          have been  in continuous  use since 1900.   It is apparent from this
          long-term experience and documented research  work that land treat-
          ment technology is a viable  alternative  to be considered as part  of
          waste management systems.

             In section 201 of the Federal Water Pollution Control Act
          Amendments of 1972, it declares that:

                 "Waste treatment management plans and practices shall
                 provide for the application of the best practical waste
                 treatment technology before any discharge into receiving
                 waters, including reclaiming and recycling of water,  and
                 confined disposal of pollutants so they will not migrate to
                 cause water or other environmental pollution and shall
                 provide for consideration of advance waste treatment
                 techniques".

             Pursuant to section 304(d)(2), which directs EPA to publish in-
          formation  on alternative treatment management techniques and systems
          available to implement section 201, the document "Alternative Waste
          Management Techniques  for  Best Practicable Waste Treatment" was
          published.  Therein it considers land application as a viable
          alternative for best practicable waste treatment.

             In addition, the Cost-Effectiveness Analysis Regulations
          which apply to all projects subject to best practicable treatment
          state that:

                 "All feasible  alternative waste  management systems
                 shall be initially identified.  These alternatives should
                 include systems discharging to receiving waters, systems
                 using land or surface disposal techniques, and systems
                 employing the reuse of waste water".
EPA Form 1320-6 (Rev. 6-72)

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                               - 2 -
    The above requirements shall be met for all projects awarded
after June 30, 1974.  This means that land treatment must be con-
sidered in the basic selection of method for waste treatment.

    I urge that you ascertain that your regional review of appli-
cation for construction of publicly-owned treatment works require that
land application be  considered as an alternative waste management
system.  If it can be demonstrated that land treatment is the most
cost-effective alternative,  is  consistent with the environmental as-
sessment, and in other aspects satisfies applicable tests, the Region
should insist that land treatment be used  and should refuse to fund
projects using other systems of waste treatment.

    Your director of Water  Programs Division has received the draft
document "Evaluation of Land Application  Systems".  This document
should be utilized during the review process.  Additional assistance
can be obtained by contacting the Municipal Construction Division
(OWPO), the Municipal Technology Division (ORD),  or the Robert
S. Kerr  Laboratory (ORD).

    In order to promulgate proper consideration of land treatment
systems by future grant applicants I  suggest that the Regional Office
provide  opportunity for public awareness of land treatment   tech-
nology.  As an example, Region III is planning a two day symposium
November  20-21,  1974  at the University of Delaware  to  highlight
land application technology. The idea for the symposium originated
in the Regional Office  and was planned cooperatively between the
regional staff and Office of  Water Program Operations headquarters
staff.  The objective of the symposium is to clarify the technical and
policy  issues involved and to chart directions for future decisions
on land treatment techniques.   The  symposium will provide useful
information to over  300 engineers, scientists, public officials  and
private citizens.   This technique or a  similar one could be used by
your region to emphasize consideration of land treatment.

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                       Attachment 2 - Werribee
    selected chemical characteristics
of soils, forages, and drainage water
       from the sewage farm serving
                 m el bourne, australia
        prepared for Department of the Army, Corps of Engineers

-------
    selected chemical characteristics
of soils, forages, and drainage water
      from the sewage farm serving
                 melbourne, australia
        prepared for
Department of the Army, Corps of Engineers

-------

-------
    SELECTED CHEMICAL CHARACTERISTICS OF SOILS,  FORAGES,
      AND DRAINAGE WATER FROM THE SEWAGE FARM SERVING
                    MELBOURNE, AUSTRALIA
                    Contributing Authors

         Lt. Richard D.  Johnson, Corps of Engineers

         Robert L. Jones, University of Illinois

         Thomas D. Hinesly, University of Illinois

         D. J. David, CSIRO, Australia
                        January 1974
                        Prepared for

                   DEPARTMENT OF THE ARMY

                     Corps of Engineers
The findings in this report are  not to be construed as an
official Department of the Army position unless so designated
by other authorized documents.

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                        INTRODUCTION









     During 1971 the U0 S. Army Corps of Engineers embarked upon




the new mission of assessing wastewater treatment technology and




planning for regional wastewater management systems.  The policy




was adopted that the Corps would develop several alternative




wastewater management plans incorporating advanced-biological,




independent physical-chemical, and land treatment technologies.




The alternative plans were developed emphasizing the technical




goals of producing a high quality of water, i.e., "no discharge




of pollutants", and incorporating wastewater reuse,  while main-




taining an active program of public involvement and education.




These plans would then be provided to the public and local




decision-makers as viable alternatives to meeting the high water




quality goals as required by Amendments to the Federal Water




Pollution Control Act, PL 92-500, October 1972.




     During the course of the Corps' Wastewater Management




Planning Studies many questions and concerns were raised about




the state-of-the-art concerning land  treatment technology.




Specifically, questions were being asked of the Corps such as:




           (1)  What are the long-term responses of a land




                treatment system?




           (2)  Will a land treatment system produce the desired




                renovated water quality?

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           (3)  What are the effects of excess water,  nutrients,




                and heavy metals on the soil and plant environments?




           (4)  What are the public health aspects associated with




                land treatment systems?




           (5)  Where can one find operating land treatment systems?




Therefore, in an effort to answer some of these questions and better




support its planning responsibility, the Corps of Engineers sponsored




an inspection trip to the Board of Works Farm, Melbourne, Australia,




where raw sewage has been irrigated over a 70-year period.  The study




team, including agronomists, planners, and engineers under the direc-




tion of Major General Willard Roper, Special Assistant to Director




of Civil Works for Water Management, Office of Chief of Engineers,




U. S. Army, made an intensive inspection and study of the Melbourne




system during the week of Ifi May 1972.




     One  important aspect of this inspection trip was to learn as




much as possible about  long-term responses of  the soil/plant




ecosystem to  sewage applications.  Accordingly,  soil and plant




samples were  collected  and  analyzed  for  their  nutrient and heavy




metal contents.  The purpose of  this report is  to present and discuss




the  findings  of this study.  Specifically,  data  resulting from the




analyses  of  soil and plant  samples  from  sites  under irrigation for




periods of 48 to  73 years will be  discussed in relation  to a  control




sample, length  of  time  under  irrigation,  resultant water  quality




produced  by  the treatment system, and  expected ranges of  constituent




concentrations  found in soils and  plants from  the  literature.

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                         BACKGROUND





     The Board of Works Farm at Werribee was established in 1897,


and currently receives raw sewage generated by the 2.5 million


people of metropolitan Melbourne, Australia.  Contributions to the


sewage flow include domestic wastes, industrial wastes, urban storm


runoff, and ground water infiltration.  The daily amounts of sewage


arriving at the Farm vary greatly depending upon rainfall.  The

                                      o
current average flow is about 546,000m /day (144 MGD), however,


peak flows as high as 1,140,000m 3/day (300 MGD) during storm periods


occur.


     Rainfall at the Farm averages 48.3 cm (19 in.) annually of


which about 32.2 cm (12.5 in.) of evenly distributed rainfall can


be expected during the irrigation season, whereas, the evapotran-


spirational potential during the same period averages about 90.4 cm


(35.6 in.), suggesting that a major portion of the annual applica-


tion of 112 cm (44 in.) of sewage water is evaporated.


     The Board of Works system utilizes three different treatment


processes at various times of the year.  Land filtration (irrigated


permanent pasture), the principal treatment method used throughout


the six to seven month summer season, encompasses  4,200 ha (10,376


A) of the total farm and treats about 273,000m 3/day(72 MGD).  This


process, which is a flood irrigation system using check borders,


allows wastewater to percolate through the soil and subsequently

-------
to be collected in deep,  open drains or ditches.   In 1897 the land




filtration area was divided into  8.1 ha (20 A)  paddocks consisting




of many individual bays which are still being used today.  Each bay




is 0.16 ha (0.4 A) in extent, and surrounded by  low check banks to




permit a 10 cm (4 in.) application of water without run-off.




Initially these bays were deep-plowed to a depth of 76 cm (30 in.)




to break up the less permeable subsoil.  The irrigation paddocks




are sown with a mixture of grasses and legumes to provide balanced




pasture production throughout the year.  Some of the sewage arriving




at the Farm goes through a primary treatment process of sedimenta-




tion providing several hours of detention.  However, part of the




older land-filtration area of the Farm is irrigated with raw sewage




without prior sedimentation.  Sewage is applied every 18 to 20 days




with each block covered to a depth of about 10 cm (4 in.).  In all,




approximately  243 ha (600 A) are irrigated each day.




     The other two treatment methods consist of "grass filtration"




(overland flow) which is used in the winter time in lieu of land




filtration, and oxidation ponds to handle the balance of the normal




flow and wet weather excess.  The processes occupy 1405 ha  (3472 A)




and 1375 ha (3393 A), respectively, while  2,830 ha (7000 A) of




the Farm are reserved for dry grazing of livestock.  Since  these




two processes were not specifically the subject of  this  investiga-




tion, they will not be discussed further.

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                                  2       2
     The Farm now includes 109  km  (42 mi ),  of which about 70


  2       2
km  (27 mi ) is devoted primarily to sewage treatment.  The 109


  2
km  of agricultural land is being used to support a large livestock



grazing operation including cattle and sheep.

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Soil and Forage Characteristics






     Much of the Board of Works Farm is situated on soils derived




from either Pleistocene basalt or Pleistocene riverine sediments,




which are somewhat variable.  The investigations presented in this




report are confined to the older part of the Farm which is almost




entirely Pleistocene alluvium of the Werribee Series (See Figure 1).




These sediments are derived from weathering products of Pleistocene




basalt.




     Although no detailed classification or mapping has been carried




out for the Farm soils, Skene (27) has completed a survey of irri-




gated soils at the Farm.  Typically, the surface of the soil




profile consists of a red-brown silty clay loam which is slightly




acid.  Calcareous silty clay occurs at a depth of about 30 cm where




the exchange complex of the clay becomes increasingly dominated by




exchangeable Mg and Na  with depth.   From particle size




distribution analyses of six core samples it was found that the




soils averaged about 35 percent clay, 45 percent silt, and 20 percent




sand.  The upper 30.5 to 91.5 cm of the  soil showed liquid limits




ranging from 32 to 41 (average about 37) and plastic limits ranging




from 13 to 22.  While the profile is only slowly permeable, the soil




can take about 2 cm of water a day.   A mixture of grasses includes




perennial rye  (Lolium pratense), Italian rye (L. multiflorum), white




clover  (Trifolium repens),  strawberry clover (T.  fragiferum), alsike




clover  (T_. hybridum) , cocksfoot  (Dactylis glomerata), timothy

-------
(Phieuro pratense), and meadow fescue (Festuca elatior).


Perennial rye grass dominates most of the irrigated land, but in


successively wetter spots there is marine barley grass (Hordeum


marinum) and docks, with water couch (Agropyron repens)  in the


wettest spots.  Under irrigation and with grazing a 2- to 5-cm


thick layer of loam rich in organic matter has developed on the

             *
surface (20).



Wastewater Characteristics


     Selected chemical and biological characteristics of raw


sewage received at the Board of Works Farm in recent time are


presented in Table 1.  These results represent data extracted


from reports of analyses of 24-hour composite samples obtained one


day each month over a 13 month period (May 1970 through May 1971).


The effluent, as it arrives at the Farm, is approximately twice as


strong as we have identified in the United States.  The principal


reason for this is the relatively low per capita use of water in

                                 3
Melbourne, which is about  0.032m /day  (84 gallons per day) at


the present time.
 References are at the end of report

-------
     Table 1.  Composition of raw sewage received at the
               Board of Works Farm during the period May
               1970 through May 1971, in ppm (24 hour
               composites taken one day each month).
Constituent

Total solids

Volatile solids

Suspended solids


Total nitrogen

Total phosphorus as PO,


Total chloride (as Cl)

BOD (5 days @ 20° C)
Average concentrations of certain heavy metals in raw sewage from

analyses of 24-hour composite samples taken during routine sampling

one day in each month from June 1968 through November 1969 (composites

prepared from  grab  samples taken at hourly intervals) are presented

in Table 2.
Number of
samples
13
13
12
13
12
9
12
Mean
1788
756
473
67.9
34.5
654
578
Standard
deviation
515
244
70
13.0
3.5
25
80

-------
     Table 2.  Heavy metals in raw sewage during the period
               June 1968 through November 1969,  in ppm
               (24-hour composites taken one day each month).
Heavy Metal
Ni
Cu
Zn
Cd
Cr
Pb
Number of
Samples
13
15
10
3
15
1
Mean
—..•••»
0.20
0.64
1.00
0.07<1>
0.55
0.55(1)
Standard
Deviation
0.091
0.17
0.58
--
0.21
« H
 •-' Includes or is sample of 17 May 1972.



Data presented in Tables 1 and 2 provide some information regarding

the quality of wastewater that is being applied to the land filtra-

tion areas today.  The authors have no information on how these

data compare with the sewage quality applied over the 70-year

history of the site.

-------

-------
                          PROCEDURE









     As previously stated, one of the primary purposes for the




Corps of Engineers visiting the Board of Works Farm was to assess




the long-term response of soils and plants to nutrients and heavy




metals applied as constituents of the sewage used for irrigation.




To help identify these responses, T. D. Hinesly and T. W.  Whitman




as members of the Corps inspection team collected soil, water,




and plant samples for laboratory analyses and available historical




data.  Significant raw sewage quality data have previously  been




presented.  Also use was made of two unpublished reports prepared




by V. G. Anderson in 1924 for D. Avery (hereafter referred to as




the Avery-Anderson report), who was the advising chemist to the




Board.  These reports presented results of a chemical examination




of raw sewage, soils, and treated effluent  for the purposes of




determining:




     "(1)  the nature and amounts of soluble (possible harmful)




           mineral salts present, and




      (2)  the fertilizing or manurial values of the samples."




The data contained in these reports for fertilizer or nutrient




effects on soils and plants offer  a point of historical comparison




with existing conditions.




     In order to have a basis for comparison, the Corps team took




the 1972 soil and plant samples from sites as close as possible to
                              10

-------
 the 1924 Avery-Anderson localities.   The following relationship

 describes the sample locations relative to  each sampling,  and is

 keyed to the sample location map (Figure 1):

                        CORPS OF ENGINEERS          AVERY-ANDERSON
 MAP COORDINATE           SAMPLES (1972)            SAMPLES /1924'>

   65W/90S                      1                         A

   65W/91S                      4                         B

   15E/110S                     2                         P

   50E/39S                      3                         K

   53E/161S                     6                         H

   55E/39S                      5                         N


Sampling Procedure

     The Corps' soil sampling procedure consisted of obtaining a

representative sample by augering at each of the six locations to

depths of 0-2.5, 2.5-18, and 25-45 cm.  Also at sample location 5

a control sample was obtained from an area that had never been

irrigated with wastewater.  Samples of several thousand grams each

were collected, split into duplicates by combining opposite quarters

after coning and quartering, and one-half of each was shipped to

D. J. David's laboratory in Australia and R. L. Jones' laboratory

in Illinois.  These sample depths do not necessarily correspond to

pedologic horizons of the undisturbed soil profile.  Rather they

reflect  the best estimate of sewage, water penetration based on

knowledge of  the soil's infiltration  capacity  and water conductivity

characteristics.   Similarly, plant samples were  collected  at  soil
                               11

-------
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-------
sample locations (except sites 1 and 4)  in the form of clippings,




bagged, and sent to D. J. David's laboratory where they were prepared




for the various analyses by drying and grinding.   Samples from sites  1




and 4 are missing because cattle had recently grazed the forage too




close to the soil surface to permit collection consistent with that at




the other sites.






Laboratory Procedure




     The soil samples were air-dried and crushed to pass a 2-mm sieve.




For pH determination, soil was mixed with distilled water in a one to




one ratio by weight and equilibrated for one hour.  For estimation of




concentrations of the elements in question that are available to plants,




20 g of each soil sample was extracted with 100 ml of 0.1 N HC1 by




shaking overnight (18 hours), centrifuged, and filtered through Whatman




No. 42 paper.  The filtrate was analyzed by atomic absorption spectro-




scopy.  For total analyses of the soils, 0.25 g of soil was digested in




a platinum crucible with hydrofluoric acid and eight drops of sulphuric




acid,  the acid fumed off and the residue taken up in hydrochloric acid




and made up to a final voLume of 50 ml.  Phosphorus was determined by




the vanadomolybdate method.  An aliquot of this digestion or of one




prepared from 5 g of soil and made to a final volume of 25 ml for




traces, was used for the determination of total metallic elements by




atomic absorption spectroscopy.  Carbon was determined by the chromic




acid oxidation method, N by  the Kjeldahl method (5) and cation exchange




capacity by determination of ammonia after saturation at pH  7 and
                               13

-------
subsequent displacement from the exchange sites (9).   Boron was




determined using the methylene blue-fluoroborate complex method '30)




in conjunction with HF-acid digestion of the soil minerals.  Plant




samples were wet digested and made to appropriate final volumes for




the determination of major and minor elements.
                              14

-------

-------
                          DISCUSSION









     In order to properly assess the information presented it is




first necessary to realize what is,  and is not, known about the




historical operation of Board of Works Farm as it would affect the




analyses presented here.  Probably the most important and obvious




unknown is the quality of wastewater that has been applied over




time.  This is particularly important in relation to the heavy




metal analyses because of the influence of the secular growth of




technology and industrialization.  For example, we suspect that Pb,




Cr, Cd, and Co levels in the sewage have been increasing especially




with the war-stimulated industrialization of Melbourne beginning in




the 1940"s.  We have assumed that the quantities of sewage applied




to long existing paddocks has not varied substantially from year to




year.







Site Selection for Sample Collection




     During the sampling phase of the investigation, an attempt was




made to collect samples from the center of the irrigation bays0




Each bay is approximately 7.6  m (25 ft) wide by 198  m (650 ft) long,




so the sampling location would be 92-107  m (300-350 ft) from the




outfall structure,,  Flood-type irrigation introduces water at the




head of the field, allowing it to flow over and through the soil,




and removes the percolate by seepage into a collection ditch at the




down-slope end of the field.  Because the wastewater and especially







                               15

-------
its solid component is not uniformly spread over the entire field,




concentrations of certain constituents will be greatest near the




outfall.  We do not know the hydraulics of this situation and there-




fore can not estimate constituent loadings at the various locations.




An example of this phenomenon is location Number 3 (Figure 1).  The




1924 Avery-Anderson reports (2)  referred to this sample as




"primarily sewage solids", suggesting that the investigators at the




time thought that the sample resembled sewage sludge (indicating a




large accumulation of solids and organic matter).  In fact, the




sampling site was located only 3.66 m (4 yd) from the sewage outfall




to the field.  This lends some validity to the statement that certain




constituents will be greatest near the outfal!0  In any case, sample




locations were ranked according to length of time in service„







Soil Composition




     It can generally be stated that if an element is present in




greater amounts in the surface horizons than in the subsoil, then




this indicates that it  is used by vascular plants, transferred to




aerial portions of the plant, and held by soil colloids and organic




matter against leaching (19).  This is certainly true of the macro-




nutrients N, P, Ca and perhaps Mg as shown in Table 3.  Soil content




of K increases with depth in both the control and treated plots and




may be  the result of marine water influence on the sediments.  This




explanation  is suggested by the low Ca/Mg ratios and the fairly




monotonous distribution of B concentration  levels with  soil depth.






                               16

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Table 4.  Comparison of N and P content in soils for the years 1924
          and 1972.  "Sewage Solids" was the description given to the
          soil sample taken at the Werribee Farm in 1924.  The Avery-
          Anderson Report (2) stated that the sample location was about
          3.66 m (4 yd) off the sewage outfall and within 7.6 cm (3 in)
          of the surface.  Sample number refers to sites located by
          number in Fig. 1.  Data for 1972 come  from Table 3 of this
          paper.,
N
Sample
Site Number 1924
Years
Control , .
Sample - O.U(a)
48 1 n.d.
58 4 0.13
60 2 n.d.
60 6 0.24
73 5 0.36
73 3 2.16
("Sewage
Solids")
P
1972 1924 1972

0.46 0.013(b) 0.053
0.65 n.d 0.154
0.88 0.026 0.135
0.89 n.d. 0.157
1.57 0.044 0.201
1.56 0.052 0.213
1.84 0.29 0.315
           (a)   Range 0.13 - 0.14

           (b)   Range 0.01 - 0.026


 (-^Estimated from sample location description in 1924 Avery-Anderson
    Report with 1972 as reference.
                                18

-------
Comparing the concentration levels of total K, Ca, and Mg presented




in Table 3 with the range of levels as given in Table 6 for normal




soils, it is noteworthy for future discussion purposes that the




Werribee Farm soils have intermediate K and low Ca and Mg contents.




     Generally, irrigation with wastewater has increased N and P




concentrations of the soil compared to those values reported here for




the control plots and those reported in 1924 as shown in Table 4.




The concentration of N in the top soil appears to be considerably in




excess of the expected normal value found in soils (compare Tables




3 and 6).  This suggests that there has been a build-up of organic




 N in the surface layer over time,  while  subsoil  concentrations




have remained rather constant as would be expected.




     Phosphorus concentrations in the surface layer fall within the




expected normal range for top soil (compare Tables 3 and 6).  Khin




and Leeper (18) reported that soil total P increased from 513 ppm to




3730 ppm for unirrigated and irrigated samples, respectively.  Their




work showed that a large percentage of the total P was organic P




(35%) with most of the remainder associated with calcium, iron, and




aluminum compounds (30, 19, and 107», respectively).  These data




indicate a sevenfold increase in total P, whereas, the present study




shows four-fold increase in total P of irrigated versus non-irrigated




samples (compare control and sample 5).  The Avery-Anderson Report




(2) indicated values for total P in the range reported by Khin and




Leeper and this study for non-irrigated samples.  Table 8 shows







                               19

-------
approximately a two-fold increase in. plant uptake of P for irrigated




versus non-irrigated samples.,




     The C content of the irrigated surface soil has increased




markedly over that in the surface horizon of the control sample, with




insignificant change in the subsoil.  Khin and Leeper (18) reported




a similar increase in organic C  from 3.7% for unirrigated soils




to 10.0% for irrigated soils..  Wastewater irrigation and current




farming practices have lowered the C/N ratio of the surface soil from




about 13/1 to an average of about 10/1.  This indicates that there




has been a substantial accumulation of nitrogenous organic matter




over time.




     Cation exchange capacity is closely related to organic C




content, increasing by 1.4 me/% C.  This relationship is derived from




the simple linear correlation of cation exchange capacity with C




that yielded the equation




                      Y = 14.67 + 1.40X,




where Y is exchange capacity and X is percent C.  The correla-




tion coefficient (r) = 0.91.  Cation exchange capacity of organic




matter in these soils, on the basis of this relationship, is 81.4




me/100 g a value consistent with figures often cited for soils.




     Soil pH is an important property in determining heavy metal




trace element availability for either plant uptake or leaching.




Khin and Leeper (18) reported that soil pH at the Board of  Works




Farm decreased from 7.5 to 6.2 for unirrigated versus irrigated areas.




The pH of the soils sampled  in this study are quite variable ranging



                             20

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 from  strongly acid  (pH 5.1)  to moderately alkaline (pH 8.4).  In




 comparison with the acid control site, the irrigated pastures




 appear  to have a higher pH.  Heavy metals become more available as




 pH  approaches a value in the lower range of 5 to 6.




      From the data presented in Table 5, applications of sewage do




 not consistantly affect the distribution of total or extractable Mn




 in  the  soil profile.  Apparently very little of the Mn applied as




 a constituent of sewage is retained in the soil profile to the depths




 sampled.  Nevertheless,  Mn and Fe are relatively unimportant addi-




 tions in sewage to  soils because they are naturally present  in soils




 at  relatively high amounts and are already managed or cropped so as




 not to  present a problem to forage production (19).  The total soil




 concentration levels presented for Mn in Table 5 are generally within




 the range reported in the literature  (Table 6) for agricultural soils.




'All of  the total soil concentration levels are at the low end of the




 range and in fact are several hundred ppm below the "typical" values




 reported.  Whether or not  an actual Mn deficiency exists is  not




 discernible from the data or visual observations of the grass plants.




 Furthermore, a Mn deficiency is not indicated by the extractable soil




Mn  content which, unlike total soil amounts, far exceeds or  is in the




 upper range of values reported for agricultural soils„




      Chromium, like Mn, is added in small amounts compared to native




 levels  and, with the exception of the 60-year treated plot (No. 6),




 displays only small variation with depth among plots.  For the most
                              23

-------
part, extractable amounts of Cr are within the concentration levels




expected in normal agricultural soils (Table 6)„




     Except for sample 3, the total concentration levels for Pb presented




in Table 5 appear to be within the range of values reported for agricul-




tural soils (Table 6).  On the other hand, the total soil concentration




levels of Pb are much greater than reported "typical" values for agri-




cultural soils including that from the control site.  In all




cases upper layers of sewage irrigated pastures contain greater total




concentration levels than are found in the surface of the unirrigated




area sampled as a control.  In the subsoil all Pb concentration levels




approach a common, low value which is consistent with the knowledge that




very little Pb migrates to lower soil depths with percolating water.




However, it was found in only two instances (Numbers 6 and 3) that




extractable lead concentration levels in  the soil surface had been




increased above non-irrigated control levels by sewage irrigation, and




in these two instances the extractable lead content exceeds levels




reported for normal agricultural soils (Table  6).  Because Pb is bound




so tightly in surface soil, it is a good  index by which to determine




how well the analytical results from the  soil  samples actually  reflect




the  length of time the area has been irrigated with sewage.  By using




Pb as an index to measure the adequacy of the  soil  sampling method,  the




greatest correspondence between total Pb  concentration  levels in soils




and  the length of  time that the particular area has been irrigated with




sewage is  found  in sample numbers  4, 6,  and 3; the  order or arrangement




 in which  they are presented in Table 5.   The  use of Pb values






                              24

-------
as an index of the actual amounts of sewage applied seems to be




corroborated and warranted by the total C contents and the cation




exchange capacity values determined for samples 4, 6, and 3.  Thus, in




the following discussion concerning the distribution of trace elements




as affected by sewage irrigation of pasture lands, a greater emphasis




will be placed on comparisons between the analytical results from these




three sampling sites in relation to those data from samples representing




the non-irrigated pasture.




     Under conditions of neutral or alkaline reaction or little soil




profile development there is scant change in trace element content with




depth (e.g., 14, 28, 31).  However, acetic acid extractable trace ele-




ment contents of soils, especially for well drained podzolic soils




where percolation of organic acids is important to development, normally




decrease with depth in the soil profile.  This phenomenon reflects major




shifts  in  form or in the nature of the compounds  in which the  trace ele-




ments are  bound.




     Referring to the Zn data  in Table 5,  it can  be  seen that  in  the




control sample total concentration levels  are  faily  uniform with  depth,




representing  a rather "typical"  soil  content,  but extractable  Zn  concen-




tration levels decrease with  soil depth.   In view of what has  been re-




ported  by  others with regard  to proportions of total and extractable  Zn




contents,  the non-irrigated Werribee  Farm  soil is typical.  Where long-




term sewage  irrigation has been practiced  both total and extractable  Zn




contents of  soils have been  substantially  increased  over those found  for




non-irrigated plots.  Nevertheless,  only samples  from  sites  irrigated






                              25

-------
for 60 (site 6)  and 73 (site 3)  years have total Zn contents  in the




soil surface layer that are much above Zn contents expected in normal




soils.  It is apparent from these data that much of the Zn applied




as a constituent of sewage has migrated to deeper zones in the soil




profile and remains in an extractable form.  The extractable  Zn




contents in the surface layer of all the irrigated sites are  above




the range of concentration levels in normal soils.  Even at the deep-




est soil sampling depth, the portion of the total Zn content  that is




attributable to sewage irrigations is much more soluble when  compared




to that in native Zn compounds of the soil.




     Recently, Jones, et. al» (16) reported increased uptake  of Cd by




soybean plants grown on sludge-amended soils.  Since increased absorp-




tion of Cd by corn plants fertilized with digested sewage sludge had




been reported earlier by the same authors  (15) many life scientists




have become greatly concerned with regard  to the potential health




hazard of this element to animal and man as municipal wastes  are




recycled to crop land.  Because of the protective action provided by




Zn, Fe, Cu, and Se for both plants and animals against the adverse




effects of Cd, the toxic hazard is best assessed by considering Cd




content in relation to contents of these other trace, elements.  There-




fore, it is important  that we consider the  relationship between the Zn




and Cd  content in raw  sewage of Melbourne  and of  these two elements




in Werribee Farm soils.  First, it should  be observed  from Table  2




that  the Cd content in  the raw  sewage  from Melbourne is higher  than




expected relative  to  the Zn  content.   The  Zn  to  Cd ratio  is  only  a




little  greater  than  14.  In  sharp contrast with  this ratio,  it  can be
                                26

-------
seen in Table 5 that where soils have been irrigated with the sewage




for a long period of time the Zn to Cd ratio in the surface layer is




in the neighborhood of 100 or somewhat greater than would be expected




in normal soils.  This relationship is even more important in view of




the fact that the unirrigated control sample has a Zn to Cd ratio of




about 47 „  One or a combination of several alternative hypotheses can




account for this relationship„  The most reasonable explanation is




that the sewage samples collected for Cd analyses did not represent




average conditions for concentration levels of the element.  If the




sewage samples taken in 1970 and 1971 are representative for Cd




contents, then the concentration levels may have been recently increased




by some metal processing waste being discharged into the sewers and this




recent change has not yet drastically altered concentration levels of the




element in irrigated soils.  Alternatively, Cd can be leaching from the




soil at a faster rate than Zn, thus widening the ratio.  Support is




given to this proposition by the decline in ratio size for both total




and extractable forms with depth which implies a fast downward movement




of Cd relative to Zn.




      By comparing the data given for total soil Cu contents in Table 5




with those for normal soils in Table 6, several facts are apparent.




For one thing, the non-irrigated soils have total and extractable Cu




contents that are within the low end of the ranges as reported for




normal soils»  Furthermore, the total Cu contents of soils which have




been irrigated with sewage for 48 to 73 years are still within the




range of values for normal soils, even though concentration levels




have been much increased in the soil surfaces and to a lesser extent
                                 27

-------
in the subsoils.  In only two instances (sites 6 and 3) do




extractable Cu contents of irrigated soils exceed that expected




from normal agricultural soils.   In these two instances  extractable




Cu contents in the 2.5 to 18 cm depth are slightly greater than




7 ppm as compared to a typical value of 2 ppm in agricultural soils.




     The total Ni contents for all the soils are within the range of




values expected in normal agricultural soils.  Unlike several of the




other trace elements applied on land as a constituent of sewage, Ni




does not appear to accumulate near the surface of the soil.  Whatever




increases in total Ni contents that have occurred in soils as a result




of sewage irrigation reflect that Ni appears mobile and has been




fairly uniformly distributed throughout the soil profile.  Extractable




Ni contents of soils suggest that a substantial amount of that added




either remains or becomes extractable by acid.  All surface-soil




samples from areas irrigated with sewage for 60 or more years  have




extractable Ni contents that range from 10 to 32 ppm which are higher




than the range of values expected for normal soils.  These levels




are also a substantial proportion of the total.  This increase in




extractable Ni content of soils irrigated with sewage over that




determined for non-irrigated controls appears to be closely associated




with the thin soil layer having a relatively high organic matter




content.




     In the proceedings of a conference held in Champaign, Illinois




in 1973 to consider the recycling of municipal sludges and wastewater




to land, it was recommended by Chaney  (8) that "Toxic metal additions




                               28

-------
to agricultural soils should not exceed Zn (equivalent) levels equal

to five percent of the C.E.C. of the unamended soil (at pH 6.5 for

sensitive crops)".  The Zn equivalent referred to is that set forth

by Chumbley (10) in which he states that:

          "Advisory experience and the results of pot experiments
          suggest that copper is twice as toxic as the same amount
          of zinc and that nickel is 8 times as toxic as the same
          amount of zinc.  Following from this the amount of toxic
          metal can be expressed as a single figure in parts per
          million by adding together the zinc content, twice the
          copper content and 8 times the nickel content and it is
          reasonable to call this the 'zinc equivalent' of the
          sewage."

     Calculations for "zinc equivalent" relevant to cation exchange

capacity are given in Table 7.  The "zinc equivalent" has exceeded

five percent of the exchange capacity on the pasture represented by

sample 6 and sample 3 is very near five percent.  These values are

conservative because they were calculated on the basis of cation

exchange capacity as determined for the respective soil sample.

Whereas, according to Chancy's recommendation the cation exchange

capacity of the sample collected from the unamended or non-irrigated

area should have been used, in which case 8.25 and 8.57 percent of the

C.E.C. for the surface-soil samples numbered 6 and 3, respectively,

are satisfied by the "zinc equivalent".  The reader may recall that

the pH values are 4.9 and 5.2 for surface-soil samples numbers 6 and

3  (Table 5) and thus, are considerably below the recommended minimum

pH value of 6.5 as suggested for the critical "zinc equivalent".

These acid conditions favor absorption of trace elements by plants.

However, at the time of soil and forage sampling, no symptoms of

                                29

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toxicity were apparent.  No effort was made to make yield determina-




tions and it is in yield reduction that excesses of toxic elements




are first recognized before overt signs of morbidity are apparent.






Plant Composition




     In the following discussion of the chemical composition data




presented in Table 8, it should be kept in mind that the quantities




of trace elements in pasture grasses and legumes vary with species




composition, characteristics of the growing season, and stage of




growth.  Thus, the amount of speculation about the toxicological




effects that the concentration levels of the several chemical elements




might present to grazing animals is very limited because the data in




Table 8 were obtained from only one sampling period.




     It was not practical to take plant tissue samples at sites repre-




sented by soil sample numbers 1 and 4.  The foliage was too short to




collect without contaminating the green forage samples with soil.  In




accordance with the grazing rotation practiced, the cattle had just




been removed from the two sites in anticipation of the next irriga-




tion with sewage.




     Comparing the chemical composition of the several Werribee Farm




samples  (Table 8) with the range in chemical composition of common




range grasses and legumes as presented in Table 9 provides some




insight  into the changes in mineral contents of forages growing on




soils irrigated with sewage for long periods of time.  First, it  is




evident  from the N content of forage samples from irrigated






                                30

-------
Table 7.  Extractable Zn, Cu and Ni contents of surface-soil horizons
          expressed as a percentage of the cation exchange capacity,
          Cu has been adjusted by multiplying that extracted by
          0.1 N_ HC1 by two and Ni by multiplying the acid extractable
          content by eight.  These conventions conform to those of
          Chumbley (10) for the calculation of the "zinc equivalent".
Sample
Number Depth
cm
Control 0-2.5
2.5
4 0
2.5
6 0
2.5
3 0
2.5
- 18
- 2.5
- 18
- 2.5
- 18
- 2.5
- 18
C.E.C.
me/lOOg
22.5
15.7
30.3
17.3
32.2
25.3
41.1
20.3
Zn

0.22
0.04
1.28
0.64
4.16
2.24
2.53
1.57
Cu

0.03
0.03
0.01
0.08
0.09
0.18
0.04
0.23
Ni
7 _ _ _ .
0.23
0.17
0.25
0.20
1.52
0.99
2.12
0.86
Sum

0.48
0.24
1.54
0.92
5o77
3.41
4.69
2.66
                                 31

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Table 9.  Range of chemical composition of common range grasses
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          roughages.  No implication is intended that the mean
          is equal to the median value within each range.
ELEMENT
N 7o
P 7o
K 7o
Ca 7»
Mg 7»
Na 7o
Mo ppm
Cu ppm
Ni ppm
Zn ppm
Cd ppm
Pb ppm
Mn ppm
Cr ppm
Co ppm
B ppm
Fe ppm
RANGE
2.55
0.19
1.16
0.62
0.15
0.30
0.1
2.0
0.1
8.0
0.2
0.1
15.0
0.1
0.05
1.0
250.0
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- 0.45
-2.76
- 0.90
- 0.35
- 0.45
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- 15.0
- 3.5
- 60.0
- 0.8
- 10.0
- 200.0
- 0.5
- 0.5
- 80.0
- 600.0
                              33

-------
and non-irrigated plots that long-term application of sewage has




resulted in significant increases of this element.  Nitrogen concen-




tration levels in the plant tissues from the control site are below,




whereas those from irrigated pastures are within, the range of values




expected in a  mixture of grasses and legumes.  Also, the plant




tissues collected from the non-irrigated site have P contents within




the expected range of values, but those from irrigated sites have




concentration levels much above the normal range of values.  Relatively




speaking, the K contents of irrigated plants have not been increased




over those from the control site to the same extent as the increases




in N and P.  In comparison to typical contents, the K




concentration level in the foliage from the control site is about




what would be expected.  Sewage irrigations have caused K concentra-




tion levels to be increased in plant tissues but the percent increase




is less than for N and P.  In spite of the relatively high uptake by




plants growing on the control plots, K concentration levels were




increased in every instance by sewage irrigation and, except for grass




samples collected at site number 3, all have K contents above the range




of values for common pasture grasses.  In sharp contrast to N, P, and




K, the contents of Ca and Mg in plant tissues have not been increased




by sewage irrigation.  In fact, there appears to have been  little if




any change in Ca and Mg content as a result of sewage irrigations.




At the same time, Ca contents appear to be lower  than that  of common




range  grasses, whereas Mg contents are within the expected range of
                                 34

-------
values.  Considering all of the elements absorbed in large quantities




by plants, the Na content of plants appear to have been increased to




the greatest extent by sewage irrigation.  In all the areas irrigated




with sewage the plants growing there contain 2 to 3 times more Na than




those growing on the non-irrigated area.  It is significant that the




Na content was increased from a value just below that expected in




common range grasses and legumes to contents much above the expected




range of values with sewage irrigation,,  Although we don't know how to




assess the increased Na  contents resulting from sewage irrigation as




it affects the health of cattle and sheep consuming the forage, it




seems appropriate to discuss the increased contents of K in forages




with irrigation and the lack of change in Ca  and Mg contents in




regards to animal health.




     A morbid condition often called grass tetany or staggers, and more




appropriately known as hypomagnesia  by animal scientists and veteri-




narians has been observed in cattle and sheep at various locations




throughout the world.  It is characterized by convulsions and paralysis




in animals having lowMg concentration levels  in  blood  serum.




The disease was recognized in beef cattle many years ago by the veteri-




narian serving the  Werribee Farm and is now avoided by adding MgO to




the dry hay fed to the animals.  This disease is not only endemic to




Werribee Farm, but rather is also widespread in Australia and especially




on areas with similar deltaic soil types.




     Grass tetany occurs when Mg  is  available  in amounts which




are inadequate to meet metabolic demands.  It is not a true deficiency




                                 35

-------
°f Mg in that it is conditioned by a number of factors such as




the .K, crude protein, and organic acid contents of forages.




In turn the forage contents of these three substances are influenced




to a large degree by N and K.  fertilization, environmental




temperatures,  and the availability of soil moisture.   All of these




factors have been discussed in some detail by Cline (11).  In 1957,




Kemp and 't Hart (17) reported that a significant correlation existed




between the number of grass tetany cases in cattle and the ratio of




K/Ca + Mg, calculated as the milliequivalents per kilogram of each




element in forage samples.  When the value of the K/Ca + Mg ratio was




less than 2.2 they found very few grass tetany cases but when the ratio




was above this critical value they found 6.66 percent of 1908 head of




cattle in their study suffered the disease.  They also present evidence




that as the K/Ca + Mg ratio increases in the pasture forages above the




critical 2.2 value, incidence of the disease increases.  When the ratio




lies between 3.01 to 3.40, 15 to 20 percent of the animals may contract




the disease.




     Because large quantities of K are supplied to the Werribee Farm




soils by sewage irrigation and under a grazing system very little K is




removed, it is of some importance to know how the K/Ca + Mg ratio have




been affected.  Not more than 10 to 20 percent of the three elements




involved in the ratio would be removed from the irrigated areas as




body constituents of the beef cattle and sheep taken for slaughter.




Therefore, the major portion  of these three elements, supplied in  the




sewage, remains on or in  the  soil unless removed in the drainage water.





                                 36

-------
     In Table 10 it can be seen that the K/Ca + Mg ratio values as




determined for the Werribee Farm forage plants are below the critical




value of 2.2 only in the samples from the non-irrigated area and in




sample 3 collected from an area which has been irrigated with sewage




for 73 years.  Forage samples  from all  the other irrigated sites have




K/Ca + Mg ratio values that exceed the critical value and thus indicate




a potential grass tetany problem when sewage is used to irrigate




pastures on soils having low Mg contents.  A strong inverse relation-




ship exists between the K/Ca + Mg values in forages and similar ratio




values calculated from the total contents of the three elements in soils.




The simple linear correlation of plant ratio (Y) with that in soil (X)




gives Y = 3.24 - 0.834X with r = -0.865 (r * 0.878 at P = 0.05).  In




view  of the data presented in Table 3, it appears that small decreases




of K and increases of Ca and Mg contents in soils have occurred as a




result of sewage irrigation.  These results are indeed surprising and




are all the more impressive because they have been observed from the




collection of such a few samples.  It is regretable that K was not




included in the analyses of water in the drains.




     In view of the decreased  soil contents it appears inconsistent for




the K content of the forage samples to have been increased by sewage




irrigations.  Furthermore, N is reported by Schutte (25) and Emmert




(13) to be antagonistic to the absorption of K by plants while at the




same time stimulating uptake of Mg.  However, the correlations between




K/Ca + Mg ratio values and N contents in forage samples from Werribee




Farm do not reflect these kinds of interactions.  A positive correlation







                                37

-------
Table 10.  Ratios of K/Ca + Mg (calculated as me/kg) in forages
           and soils and N contents in forages.  Content of N
           is included from Table 8 for comparison.
                                       K
Site            Sample              Ca + Mg               % N in
Years Old       Number                                    Forage
Control           -            1.37         2,34          1.80

  60              2            2,42         1.13          4.01

  60              6            2.24         0.84          3.44

  73              5            2.99         0.7')          3.85

  73              3            1.87         1028          3.73
                             38

-------
between the K/CA + Mg ratio values and N content, yielding




Y = 0.53 4- 0.40X with r = 0.782 (r * 0.805 at P = 0.10) is almost




significant.  Therefore, the interaction effects between N, K,  and




Mg appear contrary to what is generally reported for plants. More




thorough   study of pastures on the Farm may establish this relation-




ship more firmly.  On the other hand, Zn, Cu, Mn, and B stimulate the




uptake of K and their influence apparently is the dominant or con-




trolling factor in the sewage irrigated vegetation.




     Among the results of analyses of forage samples for 15 chemical




elements (Table 8), Mn concentration levels are the only ones which




appear with any degree of certainty to have been decreased by sewage




irrigation.  But even though Mn contents have been decreased they are




still within the range of values expected in common range grasses and




legumes.  In general, Mn absorption by plants is enhanced by K  and




depressed by Ca and Cu.  Thus, it appears that even though Mn absorption




has been decreased by sewage irrigation the overall effect is one of




stabilizing the uptake at an adequate level in plant tissues.




     Zinc contents of forage samples reflect the sewage irrigations to




the greatest extent in only those samples from the two sites numbered




6 and 3.  It may be recalled that by the use of Pb as an index,  it is




these two sites which we estimate have received the greatest loading




rates of sewage during the history of the Farm.  At these sites Zn




contents of the vegetation are more than twice the highest values




expected in common range grasses and legumes.  The fact that Ca and P




are antagonistic to Zn uptake by plants may account for the high but






                                 39

-------
reasonable levels of Zn in foliage tissues.  Since the Ca content is




low, P is probably the element which exerts the major control over Zn




absorption and translocation to aerial tissues.




     From the comparison of Cu contents of the green forage samples




from the non-irrigated control site to that contained in all of the




samples from irrigated areas, it is obvious that this metal has been




much increased in the vegetation (Table 8).  Nevertheless, only in the




sample from irrigated site 6 does the vegetation contain Cu contents




in excess of that which has been reported as normal values (Table 9).




Like Zn, the Cu content of the vegetation is probably maintained at




a tolerable level by the plant available P supplied as a constituent




of the sewage and accumulated in the soils.  Unusually high levels of




available soil P are known to be antagonistic in the uptake of Cu by




plants.




     All of the forage samples collected from sewage-irrigated sites,




except sample 5, have Cd contents that barely exceed levels expected




in common range grasses and legumes.  It may  be recalled that the




increasing Zn to Cd ratios of extractable contents in soils with




increasing loading rates of sewage were discussed above and it is of




some interest to note a similar trend for  the ratio values in the




vegetation.  In every case the Zn to Cd ratio values are greater in




forage samples representative of irrigated sites than the ratio value




of 65 determined for the sample from the non-irrigated control plot.




It is especially noteworthy that for samples numbered 6 and 3,  (sites




that have had the greatest amount of sewage applied according to the




                                 40

-------
use of the soil contents of Pb as an index) the Zn to Cd ratio values




are 117 and 160, respectively.




     In view of the reasonable extractable concentration levels in




the soils, the exceedingly high Cr contents in forage samples from




both irrigated and non-irrigated sites on the Werribee Farm can not be




explained.  From a review of the literature for reported Cr contents




found in a number of plant tissues, including pasture grasses,




Underwood (29) found 0.1 to 0.5 ppm to be the expected range of con-




centration levels and these are the values included here in Table 9.




The Cr concentration levels reported here for forage samples are




presented with reservations until additional samples can be collected




and analyzed.  Because Cr is so poorly absorbed by  animals and has




such a low order of toxicity, even if concentration levels in Table 8




are correct values they would not be considered to be a health hazard




to sheep and cattle.




     Even though it can not be said with any degree of certainty from




the data in Table 8 that sewage irrigations have increased the extract-




able Co content of soils, it appears that concentration levels are




enhanced in the  forage.  Although three of the forage samples from




Sewage irrigated pastures contain Co contents that exceed values




reported for common range grasses and legumes, the concentration levels




do not seem excessive from the standpoint of animal health.  Like Cr,




Co has a fairly low order of  toxicity in animals (29).




     As discussed above, irrigation of pastures has substantially




increased total  and extractable Pb contents of some of the soils and





                               41

-------
thus it is somewhat surprising that the Pb content of the forage grown




on the pastures is not considerably higher than that found in the




forage sample from the non-irrigated control site.  None of the forage




samples contained Pb in concentration levels equal to the higher




values expected in common range grasses and legumes.




     Although three of the forage samples from sewage-irrigated sites




have Ni contents that exceed the highest values expected in normal




pasture vegetation, no adverse symptoms of high Ni levels were apparent.




With regard to untoward effects in animals, Ni is like Cr in that it is




poorly absorbed from ordinary diets and is relatively nontoxic (29).




It appears rather unlikely that the Ni contents of any of the forages




grown on the Werribee Farm pastures represent a Ni-related health




problem to animals.




     As can be seen in Table 8, the Fe contents of forage samples are




highly variable.  The Fe content of the forage sample from the control




or non-irrigated site is much higher than that expected for normal




pasture vegetation.  Except in the forage sample  from site 6, sewage




irrigation appears to have decreased the uptake of Fe  by plants.  But




all of the forage  samples have Fe  concentration levels equal to or




greater than would be expected as  an average value.  The fact that the




greatest Fe content occurs in the  sample  from irrigated site 6 is of




special interest,  because this sample  also  contains the highest  con-




centration levels  of Ca, Zn, Cu, Cd, Cr,  and Ni.  Except for Cr,  all




of  these chemical  elements and Mn  are  known to be antagonistic to the




absorption and/or  translocatiori of Fe  into plant  foliage.  On the other




                                 42

-------
hand, K stimulates the uptake of Fe by plants and therefore may be




the off-setting or protective factor against an Fe deficiency (25).






Water Composition




     For a description of the surface drainage system, the reader is




referred to the article entitled "Waste into Wealth" which appeared




in the 1972 Fall issue of Water Spectrum (26).  In the following brief




discussion of the chemical content of the drainage water from the




Werribee Farm, it should be kept in mind that the objectives of the




Melbourne Board of Works staff at the time the farm was established




in 1893 was to use this system to reduce the suspended solids to less




than 30 ppm and the biochemical oxygen demand to less than 20 ppm




prior to discharging the wastewater to Port Phillip Bay.  To this end,




the Farm has been successful, even though the raw sewage waste loads




soon exceeded the designed capacity of the Farm after its establish-




ment.  Thus, this farm was never selected nor was the system designed




to treat raw sewage to the level of "no discharge of critical pollu-




tants" which will be the United States' goal in designing future land




treatment systems to achieve tertiary treatment of and nutrient




removal from wastewaters.




     If we assume a hydrologic equilibrium, that one volume of water




added to the paddocks is represented by one volume in the drains,




then it can be inferred from the data in Table 11 that 88 percent of




the N and 91 percent of the P is being removed from the raw sewage.




If evapotranspiration losses (90.4 cm) are considered for this area






                                43

-------
where annual precipitation is about 50 cm, than N and P removals on a




mass basis are even higher.  The averages of 5.9 ppm of total N and




and 2.9 ppm of total P in drainage waters are considerably lower values




than the 20 ppm and 10 ppm reported as typical values for N and P,




respectively, in secondary treated effluents (22).  Although the N and




P concentration levels in the farm drainage water are several times




greater than the levels expected in Port Phillip Bay (assuming average




composition of seawater as shown in Table 11), it is nevertheless of




higher quality with respect to these two elements than could have been




achieved by a secondary wastewater  treatment plant.  It was mentioned




before that it is regretable that K concentration levels in sewage and




drainage waters were not determined for use in estimating the K mass




balance, but from the standpoint of the quality of water discharging




to Port Phillip Bay it is not an important parameter.  Seawater




normally  contains about 380 ppm of K and it seems highly improbable




that the farm drainage waters would contain higher conceitration




levels.  And even if they did the values would have  little relevance




to the pollution of Port Phillip Bay.




     Of the six heavy metals whose concentration  levels were determined




in drainage waters, Ni is removed to  the  least extent by the soil-plant




system (Table 11).  In spite of the fact  that the soil-plant complex




removes only  about 20 percent of the total Ni contained in raw sewage,




it does not appear  likely  that secondary  treatment would reduce the Ni




content to lower levels.  An average  value  for Ni concentration levels




in secoadary effluents has been reported  to be about 0.2 ppm  (23).   By




                                 44

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either treatment method the Ni content in waters discharged to Port




Phillip Bay would continue to be greater than is normally found in




seawater.




     Again, with respect to the contents of the six heavy metal species




determined La the drainage waters, only Gu is within the range of con-




centration levels expected in seawater.  Furthermore, Cu concentration




levels in the Farm drainage water are about the same as levels expected




in municipal effluents having secondary treatment.




     A comparison between the raw sewage contents of Zn, Cd, Cr, and




Pb with their concentration levels as determined in drainage  water




(Table 11), indicates that the irrigated-pasture system is removing




78 to 91 percent of these chemical elements.  These removal rates are




as great if not greater than can be achieved with a well managed




secondary treatment plant.  However, the concentration levels of all




of these four metals are higher in drainage water than would be expected




in seawater.  On the other hand, we do not have concentration levels




of the several chemical element species in drainage water  from similar




basalt derived deltaic soils irrigated with waters other than that of




raw sewage.  Thus, we don't know the contribution of native mineral




weathering to concentration levels in drainage water.




     Because of odor problems if for no other reason, it does not seem




likely that sanitary district staffs in more densely populated areas




of the United States will consider the use of untreated  sewage to




irrigate pastures and crop lands.  On  the other hand, a  rapid increase




in the use of secondary treated effluents for irrigation can be




                                46

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expected as laws and regulations are enforced requiring tertiary treat-




ment of municipal effluents before discharge to streams.  Already




treated effluents from many municipalities in arid and semiarid regions




are used to irrigate golf courses, parks and crops of various kinds.




Many of these operations provide the opportunity to determine the




efficiency with which soil-plant systems remove nutrients and trace




elements from the applied effluent.  Such information would be more




relevant to future land treatment systems than that reported here.




The results reported here are from a system that has been stressed




with considerably higher concentration levels of macronutrients and




trace elements than would be applied where only secondary effluents




are used for irrigation over an equivalent period of time.  But the




Werribee Farm analyses are valuable from the standpoint of illustrating




the tremendous capacity of the soil-plant complex to attenuate water




pollutants by precipitation, adsorption, absorption, and assimilation.




Furthermore, the results demonstrate the capacity of growing plants




to buffer the effects of abnormally high soil contents of essential




and non-essential chemical elements on animal health.
                                 47

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                             SUMMARY









     From the results of this cursory investigation of the chemical




characteristics of sewage, soils, forage, and drainage waters from the




Werribee Farm, some of the more important observations are as follows:




     1.  The irrigation of pastures with raw sewage at an annual rate




         of about 111.8 cm (44 in) per year for a period of 48 to 73




         years has resulted in increased soil contents of N, organic




         C, and P.  As C increases, cation exchange capacity increases




         1.4 me per percent C.  Soil C/N ratios decrease with sewage




         irrigation while Ca/Mg ratios increase indicating greater




         accumulations of N and Ca relative to C and Mg, respectively.




         Contrary to what was anticipated, soil K contents remain




         unchanged or declined with sewage irrigation.




     2.  With some exceptions total soil contents of all trace elements




         included in the soil analyses were increased by sewage irriga-




         tion.  However, increases for total contents of both Ni and




         B were consistently  less than anticipated in view of amounts




         contained in sewage.  In spite of small increases in total




         Ni, extractable soil contents of Ni were increased  to levels




         considerably higher  than in normal soils.  In general trace




         element contents extractable with 0.1N HC1 increased with




         sewage irrigation, most notable of which was Zn.  Contrary to




         expectation, Zn to Cd ratios of both total and extractable




         contents in soils were  increased with sewage irrigation.  From






                                 48

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    the calculation of the "Zn equivalent,"  as proposed by others




    as a means for limiting municipal waste  application on land,




    it is evident that at two sites,  loading rates have already




    exceeded recommended amounts.




3.  Sewage irrigation of pasture land has resulted in increased




    or unchanged forage contents of all the  chemical elements




    determined, except Mn.  This one element was decreased, but




    not to the extent that it would be considered to be at a




    deficiency level in grasses and legumes.  Large increases in




    forage contents of N, P, K, and Na have  occurred as a result




    of sewage irrigations.  Calcium and Mg contents of forage




    have not been changed by irrigation.  Because of the increased




    uptake of K by plants in the presence of little change in Ca




    and Mg contents of forage, irrigation has increased the




    probability of grass tetany in cattle and sheep.  In at least




    two of the forage samples from irrigated pastures, Zn, Cr,




    and Ni contents were considerably greater than would be




    expected in normal grasses and legumes.   But the concentration




    level of Cr was also higher in the  forage sample from non-




    irrigated control sites  than expected.  These three essential




    elements for animals have a low degree of toxicity and thus




    their concentration  levels do not indicate harmful effects to




    animal health.  In terms of animal  health there are no indica-




    tions that forage from  irrigated sites  contain  trace elements




    in  either excessive  or  deficient amounts.





                           49

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4.  Results of this investigation suggest that  drainage  effluents
    from the Farm contain considerably less  N and P than is
    generally found in secondary effluents from biological waste-
    water treatment plants.   Therefore it is concluded that  the
    Melbourne Board of Works sewage irrigation  operation has
    provided a greater degree of protection against the  pollution
    of Port Phillip Bay than could have been obtained by biological
    secondary treatment.  Concentration levels  of several heavy
    metals in the Farm drainage water are about the same as
    expected in secondary-treated municipal waste waters. Except
    for Cu, all of the elements included in the analyses of  farm
    drainage water occur in higher concentration levels  than would
    be expected in seawater.
5.  Hopefully this cursory examination of a sewage farm has  contrib-
    uted information toward answering some of the more salient
    questions about land disposal of raw sewage and will stimulate
    a more comprehensive study of the Melbourne operation,  the
    objectives of which should be the establishment of the mass
    balances of the macro- and microelements in this system  and
    the accurate description of the chemical and physical mechanisms
    operating in the system.  Data from sewage  farms that have been
    in operation for long periods of time are useful for predicting
    the fate of many water pollutants, particularly where their
    contents in untreated sewage results in application rates on
    soils which are considerably greater than would occur on a
    land treatment system utilizing secondary effluents.
                            50

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                         ACKNOWLEDGEMENTS






     Sherwood Reed, U. S. Army Cold Regions Research and Engineering




Laboratory, and Dr. Rufus Chaney, Agricultural Research Service,




Beltsville, Maryland, reviewed and commented on this manuscript.




Of course, the content and conclusions remain the responsibility




of the authors.  The authors wish to acknowledge the Board of Works




Farm for providing valuable  water quality data, and W. T. Whitman,




Chief, Western Reports Management Branch, Planning Division,  Civil




Works Directorate, U. S. Army Corps of Engineers, for assistance  in




field sampling and data collection.
                              51

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                               54

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