EPA-600/3 77-129
November 1977
Ecological Research Series
               SEPTIC TANK  DISPOSAL  SYSTEMS  AS
                                PHOSPHORUS  SOURCES
                                FOR SURFACE  WATERS
                               Robert S. Kerr Environmental Research Laboratory
                                       Office of Research and Development
                                      U.S. Environmental Protection Agency
                                               Ada, Oklahoma 74820

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                RESEARCH REPORTING SERIES

Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology.  Elimination  of traditional grouping was  consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:

      1.  Environmental  Health Effects Research
      2.  Environmental  Protection Technology
      3.  Ecological Research
      4.  Environmental  Monitoring
      5.  Socioeconomic Environmental Studies
      6.  Scientific and Technical  Assessment Reports (STAR)
      7.  Interagency Energy-Environment Research and Development
      8.  "Special" Reports
      9.  Miscellaneous Reports

This report has been assigned to the  ECOLOGICAL RESEARCH series. This series
describes research on the effects of pollution on humans, plant and animal spe-
cies, and materials. Problems are assessed  for their long- and short-term influ-
ences. Investigations include formation, transport, and pathway studies to deter-
mine the fate of pollutants and their effects. This work provides the technical basis
for setting standards to minimize undesirable changes in living organisms in the
aquatic, terrestrial, and atmospheric environments.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia  22161.

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                                         EPA-600/3-77-129
                                         November  1977
   SEPTIC TANK DISPOSAL SYSTEMS AS PHOSPHORUS
           SOURCES FOR SURFACE WATERS
                       by

        Rebecca A. Jones and G,  Fred Lee
             Environmental Sciences
          University of Texas at Dallas
             Richardson, Texas 75080
               Grant No.  R-804549
                 Project Officer

                  D. Craig Shew
          Ground Water Research Branch
Robert S.' Kerr Environmental Research Laboratory
               Ada, Oklahoma 74820
            This study was conducted
               in cooperation with
  EnviroQual Consultants and Laboratories, Inc.
               Piano, Texas 75074
ROBERT S. KERR ENVIRONMENTAL RESEARCH LABORATORY
        OFFICE OF RESEARCH AND DEVELOPMENT
      U.S. ENVIRONMENTAL PROTECTION AGENCY
               ADA, OKLAHOMA 74820

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                            DISCLAIMER

     This report has been reviewed by the Robert S. Kerr Environ-
mental Research Laboratory, US Environmental Protection Agency, and
approved for publication.  Approval does not signify that the con-
tents necessarily reflect the views and policies of the US Environ-
mental Protection Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for
use.

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                             FOREWORD

     The Environmental Protection Agency was established to coordi-
nate administration of the major Federal programs designed to pro-
tect the quality of our environment.
     An important part of the Agency's effort involves the search
for information about environmental problems, management techniques,
and new technologies through which optimum use of the Nation's land
and water resources can be assured and the threat pollution poses
to the welfare of the American people can be minimized.
     EPA's Office of Research and Development conducts this search
through a nationwide network of research facilities.
     As one of these facilities, the Robert S. Kerr Environmental
Research Laboratory is responsible for the management of programs
to:  (a) investigate the nature, transport, fate and management of
pollutants in groundwater; (b) develop and demonstrate methods for
treating wastewaters with soil and other natural systems; (c) de-
velop and demonstrate pollution control technologies for irriga-
tion return flows; (d) develop and demonstrate pollution control
technologies for animal production wastes; (e) develop and demon-
strate technologies to prevent, control or abate pollution from
the petroleum refining and petrochemical industries; and (f)  de-
velop and demonstrate technologies to manage pollution resulting
from combinations of industrial wastewaters or industrial/municipal
wastewaters.
     This report contributes to that knowledge which is essential
in order for EPA to establish and enforce pollution control stand-
ards which are reasonable, cost effective, and provide adequate
environmental protection for the American public.
                                    William C.  Galegar
                                         Director
                                111

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                             ABSTRACT

     A four-year groundwater monitoring study was conducted in
the immediate vicinity of an active septic tank wastewater
disposal system in the sandy substrate in Burnett County of north-
western Wisconsin to determine the potential for this method of
wastewater disposal to contribute to excessive fertilization of
surface waters.  To monitor the movement of the effluent and the
character of the area groundwater, the following parameters were
measured in water samples collected from an array of wells located
up and down groundwater gradient from the septic tank tile field:
specific conductance, pH, alkalinity, Na , Cl , K ,  Mg  ,  Ca  ,
soluble orthophosphate, total phosphorus, and various forms of
nitrogen.
     During the course of this study, movement of septic tank
effluent in the groundwater was indicated by measured values of
several of these parameters.  However, there was no  evidence
of the transport of the phosphate from septic tank effluent through
the groundwater even at the monitoring point closest to the tile
field (about 15 m down groundwater gradient from the tile  field).
The results of this study confirm the conclusions drawn from
similar studies in other areas reported in the literature, that
phosphorus from septic tank wastewater disposal system effluent
is usually not readily transported through the groundwater.  There-
fore, septic tank wastewater disposal systems generally do not
contribute significant amounts of phosphorus to surface waters
to contribute to their excessive fertilization.
     This report was submitted in partial fulfillment of Grant
R-804549 by the University of Texas at Dallas under  the sponsor-
ship of the US Environmental Protection Agency.
                                IV

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                             CONTENTS
Foreword	   iii
Abstract	    iv
Figures	    vi
Tables	   vii
Conversion Table 	  viii
Acknowledgment 	    ix

   1.  Introduction  	     1
   2.  Conclusions and Recommendations 	     3
   3.  Literature Review 	     5
            Factors controlling phosphorus transport ....     5
            Field studies on phosphate transport from septic
              tank systems	     6
            Summary and conclusions from literature  ....    18
   4.  Experimental Procedures and Characteristics of Area .    19
            Climate	    23
            Qualitative description of soils and geology .  .    23
            Sorption tests 	    26
            Hydrology and water quality  	    28
                 Groundwater velocity  	    28
                 Groundwater quality 	    30
                 Surface water quality 	    36
   5.  Results	    38
            Septic tank use	    38
            Observation well monitoring  	    38
   6.  Discussion	    52

References	    58
                                v

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                             FIGURES


Number

  1     Location of Hydrologic Test Wells - Voyager
          Village Development Area 	   20

  2     Test Wells for Septic Tank Monitoring Study -
          Voyager Village Development Site 	   22
  3     Groundwater Flow Pattern - Voyager Village
          Development Site	29

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                              TABLES
Number                                                       Pag

  1     Sieve Analyses on Selected Samples - Voyager
          Village, Burnett County ..............  25

  2     Phosphate Sorption Tests on the Voyager Village
          Development Area Soil ...............  27

  3     Chemical Analysis of the Well Point Samples from
          Voyager Village Project ..............  31

  4     Chemical Analysis of Surface Waters in Voyager
          Village Development Area (June 9, 1970) ......  34

  5     Voyager Village Septic Tank Monitoring Study Obser-
          vation Well Data (February 3, 1972) ........  39

  6     Voyager Village Septic Tank Monitoring Study Obser-
          vation Well Data (February 16, 1972)  .......  tl
  7     Voyager Village Septic Tank Monitoring Study Obser-
          vation Well Data (April 17, 1972) .........  42

  8     Voyager Village Septic Tank Monitoring Study Obser-
          vation Well Data (August 29, 1972)  ........  44

  9     Voyager Village Septic Tank Monitoring Study Obser-
          vation Well Data (October 29, 1972)  ........  45

 10     Voyager Village Septic Tank Monitoring Study Obser-
          vation Well Data (January 25, 1973)  ........  47

 11     Voyager Village Septic Tank Monitoring Study Obser-
          vation Well Data (July 26, 1973)  .........  48

 12     Voyager Village Septic Tank Monitoring Study Obser-
          vation Well Data (October 10, 1974)  ........  49

 13     Voyager Village Septic Tank Monitoring Study Obser-
          vation Well Data (January 15, 1976)  ........  51

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                     CONVERSION TABLE
MULTIPLY
meters
cm
liters
I/cm /day
I/day
percent/m
kg
  BY
 3.28
 0.39
 0.26
215.8
 0.26
0.305
  2.2
TO OBTAIN
feet
inches
gallons
gpd/ft2
percent/ft
Ibs
                           vni

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                          ACKNOWLEDGMENT

     This investigation was supported by N.E. Isaacson and Asso-
ciates of Reedsburg, Wisconsin.  Several employees of N.E. Isaacson
and Associates contributed significantly to the project.  Particu-
lar mention is given to Ken Carlson.   Also, the assistance of D.A.
Stephenson and D. Huff of the University of Wisconsin-Madison is
greatly appreciated.  Further, assistance was provided by Owen £
Ayres, engineering consultants of Eau Claire, Wisconsin.  In addi-
tion, support for preparation of the final report was given by the
FMC Corporation, Philadelphia, Pa.,  the Center for Environmental
Studies, University of Texas at Dallas, Richardson, Texas, and
EnviroQual Consultants and Laboratories, Piano, Texas.
                                 IX

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                            SECTION 1
                           INTRODUCTION

     The Voyager Village recreational development located in
Burnett County, Wisconsin, has been criticized because of poten-
tial problems of ground and surface water contamination result-
ing from septic tank wastewater disposal system effluent.  The
primary concern was the potential for aquatic plant nutrient
(nitrogen and phosphorus compounds) contamination of surface
waters which could result in excessive growth of algae and
other aquatic plants in nearby lakes.
     Normally, effluents from septic tank wastewater disposal
systems contain large quantities of nitrogen in the form of
ammonia and organic nitrogen and phosphorus in the forms of
ortho and condensed phosphate and organic phosphorus.   A large
part of the organic nitrogen and phosphorus compounds are pre-
sent in particulate forms.-  In the soil, the particulate forms
are filtered out in a relatively short distance from a tile
field.  Bacterial reactions convert part of the particulate
organic forms to soluble ammonia and orthophosphate.  The con-
densed phosphates are primarily derived from detergents and are in
the form of tripolyphosphate and pyrophosphate.  In aerobic sys-
tems, the tripolyphosphate is hydrolyzed to pyrophosphate and
orthophosphate; the pyrophosphate is hydrolyzed to orthophosphate„
Although no data are available on the hydrolysis of the condensed
phosphates in aerobic systems such as those found near the tile
field of a septic tank system, it is reasonable to suspect that
hydrolysis will occur in groundwater systems although the rate
could be somewhat slower than in surface waters.
     The ammonia and phosphate present in septic tank effluent
tends to be sorbed by the aquifer material in most groundwater

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 systems.   However,  in  the  presence  of  oxygen  in  the  groundwater
 the  ammonia  will  be oxidized  to  nitrate.   The nitrate  is poorly
 sorbed by aquifer materials and  is  readily transported in  ground-
 water.  There  are some groundwater  systems with  low  dissolved
 oxygen content that tend to cause some loss of nitrate through de-
 nitrification  reactions to nitrogen gas.   Although this reaction
 is generally thought to be a  biochemical  process,  there is evidence
 that chemical  denitrification occurs.   It should be  emphasized
 that the extent of  the denitrification reaction  is such that the
 majority of  the nitrate is transported by groundwater  and  is not
 lost as nitrogen  gas.
      Generally, phosphate  is  fixed  by  the soil particles in the
 aquifers and normally  is poorly  transported in groundwater.  How-
 ever,  in some  sand  aquifers,  like those found in many  parts of
 Wisconsin, the sorption capacity of the aquifer  material for phos-
 phate  is lower than for many  clay soils.   It  is  not  possible,
 however,  to  generally  state that all sand aquifer  systems  will
 transport phosphorus.   The key to holding phosphorus within an
 aquifer system is the  presence of small amounts  of clay minerals,
 iron oxide,  aluminum oxide or limestone,  all  of  which  would tend
 to fix the phosphate in the soil.   Therefore,  a  sand aquifer
 system which contains  some of these materials  would  retain phos-
 phate  more readily  than a  sand aquifer system without  them.
      In order  to  investigate  the potential for phosphate and
 other  contaminant transport from septic tank  wastewater disposal
 systems that are  being used in the  Voyager Village development
 area (Burnett  County,  Wisconsin) it was decided  to conduct a
 several-year field  study which would provide  data  necessary to
 determine the  likelihood of significant phosphate  transport
from the septic tank wastewater disposal systems  effluent to sur-
 face waters  in the  development area.

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                           SECTION 2
                CONCLUSIONS AND RECOMMENDATIONS

     It can be concluded from the groundwater monitoring study in
the Voyager Village development area that there was transport of
septic tank effluent down groundwater gradient from the septic
tank tile field.  This was generally evidenced by patterns of
specific conductance, chloride, and alkalinity values.   There was
also limited transport of nitrate in the groundwaters.   During the
four-year study period, there was no evidence of phosphorus from
septic tank effluent in the observation wells down groundwater
gradient from the septic tank wastewater disposal system.
     If area lakes receiving groundwater from the development area
are typically phosphorus limited, the installation of septic tank
wastewater disposal systems in the Voyager Village development area
should not degrade existing surface water quality.  However, where
lakes of the area are nitrogen limited during the period of maxi-
mum algal growth, there is a potential for some increased aquatic
plant growth due to contributions of nitrate from septic tank ef-
fluent.
     The results of this study strongly support the conclusions
drawn from similar studies reported in the literature,  that the
phosphate present in septic tank wastewater disposal system ef-
fluent would not, in general, be expected to contribute signifi-
cantly to the excessive fertilization of surface waters.
     While significant transport of phosphorus from septic tank
wastewater disposal system effluent to surface waters is ex-
pected to be rare, there are situations where this would occur.
In those situations  where it is not possible to construct a
sewerage collection system, consideration should be given to

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modifying the septic tank disposal system to increase phosphate
retention capacity.  There are a number of engineering questions
that remain to be resolved in order to provide some general guide-
lines for design of the modified system in order to minimize cost
and maximize phosphate removal.  It is recommended that studies be
conducted to provide general guidelines on the design of modified
septic tank wastewater disposal systems to increase their phos-
phate retention capacity.
     There is little need for additional research on the mechanisms
of phosphorus immobilization in soils.  While there are still
several unanswered questions in this area, further work along
this line is likely to yield a rather limited amount of addition-
al information which could be used to readily ascertain whether a
particular septic tank wastewater disposal system is contributing
a significant amount of phosphate to nearby surface waters.  Ques-
tions of this type have to be approached on a case-by-case basis
so that through the monitoring of an appropriate series of wells
and an understanding of ground and surface water hydrology, it
would be possible to establish whether or not phosphate transport
was occurring from a particular system.  It should be possible to
develop a laboratory phosphate transport test system in which the
expected amount of transport that may occur in the field could be
estimated.  It is recommended that studies in this area be con-
ducted.

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                            SECTION 3
                        LITERATURE REVIEW*
FACTORS CONTROLLING PHOSPHORUS TRANSPORT
     There are a number of factors controlling phosphorus trans-
port from septic tank wastewater disposal system effluent to sur-
face waters in sufficient quantities and in available forms to af-
fect surface water quality.  Based on previous studies of the chem-
istry of phosphorus in natural water systems, it is expected that
the potential of a soil to remove phosphate from septic tank waste-
water disposal system effluent is controlled by the mineralogy of
the area soils rather than by the soil particle size.  A review of
the literature pertaining to reduction of phosphate concentrations
by soil and subsoil systems indicates that one of the primary fac-
tors in P removal is the tendency of phosphorus to sorb on aquifer
materials or on soil or subsurface particles.  In addition, in
calcareous areas, phosphate can be precipitated as hydroxyapatite
in the groundwater system. Lee (1976b) pointed out that in hard-
water areas such as are found in the southern half of Michigan,
the likelihood of significant phosphate transport from septic tank
wastewater disposal system effluent to the surface waters is great-
ly reduced because of the calcium carbonate present in the soil
and subsoil systems.
     The importance of sorption and precipitation reactions is
readily demonstrated when one examines the chemical characteristics
of groundwaters.  It is rare that groundwaters have high phosphorus
content.  The total phosphorus is rarely more than a few tenths of
a milligram per liter (Dudley and Stephenson, 1973; New York State
Department of Health, 1972; Stumm and Morgan, 1970).  In the re-
view of phosphate removal by sands and soils by Tofflemire ejt al.
(1973), it is stated that the natural groundwater concentrations
*Standard units of measure have been converted to the metric  system,
 Refer to Conversion Table, p.  viii, for explanation.

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often range from 0.01 to 0.06 mg/1 P.   Also, according to Enfield
(1976), the phosphorus concentration in naturally occurring ground-
water is typically 0.05 mg/1 or less.   As discussed by Enfield and
Bledsoe (1975), seven literature values for phosphorus concentra-
tions in ground and subsurface drainage water from agricultural
land and beneath wastewater treatment systems showed that concen-
trations generally ranged from about 0.005 to 0.1 mgP/1.   The low
concentrations of phosphorus present in groundwaters can be attri-
buted to a combination of sorption and precipitation reactions.
These same reactions would be applicable to the phosphorus present
in septic tank wastewater effluents.
FIELD STUDIES ON PHOSPHATE TRANSPORT FROM SEPTIC TANK SYSTEMS
     Thomas (1976) indicated that Allum used the work of Dillon
and Rigler (1975) and Viraghavan and Warnock (1976a) as support
for his position that there is limited retention of phosphorus by
soils adjacent to septic tank wastewater disposal systems.  Soils
used in the Viraghavan and Warnock study, Thomas claimed, were
similar to those in Michigan.  Examination of the paper of Virag-
havan and Warnock (1976a) shows that no mineralogical information
is given upon which one can judge the similarity or lack thereof
of the soils in Michigan compared to soils near Ottawa, Canada,
where their study was conducted.  The authors (Viraghavan and
Warnock) had significant experimental problems in their study.
Even if the results are taken at face value, their data indicates
25 to  50 percent retention of phosphorus.  This amount is con-
siderably  greater than the 10 percent figure that Thomas attempted
to justify.
     The other paper  cited by Thomas in  support of his position
was that of Dillon and Rigler  (1975).  Upon  examination of the
retention  coefficients formulated by Brandes et_ al.  (1971) pre-
sented therein,  in only the  five  coarse  sands tested  was the  frac-
tion of phosphorus retained  less  than  50  percent.  The other  sands
and  sand-silt  or  sandy-clay  mixtures showed  63 to  88  percent  phos-
phorus retention.  One of these coa.rse  sands had a phosphorus

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retention of 48 percent.  Only two coarse sands showed retention
of less than 10 percent.
     Keeley (1976),  Chief,   US EPA Groundwater Research Program,
stated that, in general, the only place they have encountered sig-
nificant phosphate transport in groundwaters is in association
with coarse sands, and even there, the movement in many instances
is very slow.
     Henderson (1969) stated that in his investigation of Gull
Lake, Michigan, there appeared to be a relationship between the
presence of septic systems 15 m or less from the lake and the
observation of aquatic weed growth along the immediate shore.  He
also stated, however, that aquatic weed growth was more frequent-
ly noticed by those residents who water and fertilize their lawns.
Visual examination of his figures showing these relationships
shows a strong relationship between residents who fertilize their
lawns and observation of aquatic weed growth in the adjacent shore-
line.  Henderson's justification for the possibility that this re-
lationship may be tenuous is inconclusive since relationships be-
tween types of fertilization practices and increased aquatic plant
growth observations were not properly weighted according to num-
bers of people using each fertilization method.  Based on data
given, it would be difficult to sort effects of fertilization and
distance of septic tanks from the lake.
     In five samples collected in tile lines draining toward Gull
Lake, Ellis and Erickson (1969b) found that phosphorus content
varied from 0.028 to 0.07 mg/1 P, indicating negligible transport
of phosphorus from those septic tank system effluents.
     In the Gull Lake investigations of the effect of phosphorus
load on distance of phosphorus movement, Ellis (1971) found that
at four of the ten sites sampled, the profiles contained so much
phosphorus, apparently from fertilizers according to Ellis, that
the determination of phosphorus movement from septic tank dis-
charge was very difficult.  Three additional locations showed suf-
ficient interference from fertilizers to make the determination
of the distance of phosphorus movement from the septic tank dis-
charge difficult.    He  concluded that, in general, based on the
                                 7

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remaining sites,  the distance phosphorus moved increased with in-
creased soil P rating (a measure of phosphorus load from the resi-
dences ).
     Ellis (1971) also studied the distance of phosphorus movement
for the various soil types in the area.  All of the soil types
surrounding Gull  Lake (Beliefontain sandy loam, Bellefontain loam,
Fox sandy loam, Fox gravelly loam, Fox loam, muck with fill) were
represented in the study except the Ostemo sand.  The quantity of
this sand in the  Gull Lake area was reported to be small.  In this
part of his study, movement of phosphorus from the surface (from
fertilizers) made it difficult to assess movement from septic tank
effluent.  Only four of the 16 locations showed no apparent move-
ment from the surface.  In the 12 locations where estimations of
movement could be made, only three showed phosphorus movement from
the point of effluent discharge greater than 6 m.  Maximum phos-
phorus movement found was 9 m.  Ellis stated that until the soils
become saturated with phosphorus, nearly 98 percent of the phos-
phorus entering the ground would be adsorbed by soils.  He made
the observation that 75 percent of the lawns surrounding Gull
Lake were saturated with phosphorus from fertilizers.  This would
allow the phosphorus in those areas to largely pass through the
soil.
     An estimation of the annual phosphorus load transported into
Houghto.n Lake, Michigan, by groundwaters, was made by Childs (1974).
This estimation was based on groundwater sample analyses, an area
water budget, and net flow calculations.  It was estimated that
groundwater transports from all sources a maximum of 450 kg of
phosphorus into Houghton Lake annually.  This represents 98 per-
cent removal of the estimated 18,000 kg of phosphorus discharged
annually by local residents via septic systems.  Since the phos-
phorus mass is not present in local groundwaters and only trace
amounts could be adsorbed above the groundwater, Childs concluded
that phosphorus is sorbed below the water table.  He further con-
cluded that it appeared that the adsorptive capacity of soil may
be as great under water saturated conditions as under aerated con-
ditions.  Childs concluded that the majority of phosphorus

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 discharged  through septic  tank  systems  in  the Houghton Lake area
 has  been, and is  being,  retained  by  soils  and sediments within the
 zone of saturation.
      In a study of six septic tank disposal  systems in Nassau and
 Suffolk Counties  (Long Island), New  York,  conducted by the New
 York State  Department of Health (1972), it was concluded that phos-
 phate reductions  were rapid and almost  total in the distances from
 septic  tank wastewater disposal systems studied.  Soil porosities
 at Sites 1, 2, and 3 ranged from  29  to  38 percent.  The soil char-
 acteristic  at  Site 1 was predominantly medium to coarse sand and
 gravel;  distance  to the  groundwater  was 2.4m.  There were two cess-
 pools on the  site,  one receiving  the majority of the waste, the
 second  receiving  some waste and overflow from the first cesspool.
 Despite  the fact  that the  first pool was full and overflowing into
 the  second  pool,  substantial leaching from the first pool was in-
 dicated.  Only data from the monitoring of one pool (apparently
 the  first) was presented.  Decreases in phosphorus content of 97
 to 99 percent by  24 m downgradient from the one cesspool site
 monitored were found, where total P  ranged from 1.7 to 0.99 mg/1.
 Between  26 and 57  percent  decrease was found at 4.6 m below the
 cesspool.  Average percent reduction found at that site was about
 4.6  percent/m.  An adjustment of this decrease for dilution showed
 that removal of 1.7 to 2.1 percent/m was due to factors other than
 dilution in the saturated  zone.
     At their Site  2 (cesspool site), also in medium to coarse
 sands and gravel where the distance  to the groundwater was 2.4 m,
 99 to greater than 99.9 percent total phosphate reduction was
 found at a point 20 m downgradient where concentrations in the
 groundwater varied from 0.03 to 0.6 mg/1 P.  Between 32 and 69
 percent reduction of phosphates was found 7.6 m downgradient from
 the cesspool.
     The third site in the Long Island study, on which one cess-
 pool was located,  contained medium to coarse sands and gravel.
Distance to the groundwater was 9m;  average groundwater

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velocity was 0.37 m/day.  In the first 1.5 m downgradient,  in
unsaturated soils, 44 and 76 percent phosphorus reductions  were
found on the two sampling dates.  At 14 m, the phosphorus had
been reduced a total of 72 and 97.7 percent, respectively.   Average
reductions of phosphorus were 2.5 percent/m and 9.0 percent/m
through the unsaturated soil zone (from the cesspool to the well
located about 4.6 m from the cesspool).  Average phosphate  reduc-
tion in the saturated zone by about 18 m from the cesspool  was,
discounting decrease by dilution, 4.7 to 8 percent/m, indicating
factors other than dilution accounting for the majority of  de-
crease in concentration in the saturated zone.  In the limited
study of vertical migration done on this site, 34 and 52 percent
phosphorus reduction took place in the first 0.46 m of unsaturated
material beneath the cesspool.
     Subsoil at Site 4 consisted of silty sand with traces  of gra-
vel; distance to the groundwater was 5 m.  There were two cess-
pools at the site, but only one received wastes during the  study
period.  Net P reductions of 98.6 to 99.8 percent were found with-
in 9.4 m downgradient from the cesspools resulting in background
phosphorus levels in the groundwaters within 9.4 m of the cess-
pools.  Overall average reductions during travel through the un-
saturated zone were 25.1 and 27.0 percent/m, whereas in the
saturated zone, decreases were 15.6 and 32 percent/m, respectively.
Disregarding dilution effects in the saturated zone, 11.9 and 26.3
percent/m decreases, respectively, were found.
     The Long Island, New York study also monitored two septic
tank-tile field systems, one in medium to fine sand  (Site 5) and
another in sandy clay, grit and stones (Site 6).  Distances to
groundwater were 1.4 and 2.4 m at Sites 5 and 6, respectively.
Their summary of percent P reduction showed 63 to 82 percent re-
duction within the Site 5 tile field.  Beneath the tile field at
Site 6, P reduction ranged from 99.7 to 99.8 percent with result-
ing groundwater concentrations of 0.14 to 0.21 mg/1  P.  They con-
cluded that the increase in P reduction at  Site 6 could be at-
tributed to optimum conditions for phosphate reduction, namely

                                 10

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 finer soil  to  encourage  entrapment  of precipitated phosphates as
 well  as  the relatively new unsaturated  soil horizon which would
 enhance  adsorption  potential.   In addition, greater water use at
 Site  5 and  character  of  sewage  produced there purportedly influ-
 enced reduction.  In  these investigations, only total P values
 were  presented.   The  authors indicated  that the ortho and total
 phosphate values  were essentially the same.
      Hansen (1968)  and Boyle and Polkowski (1970) (as cited in
 Dudley and  Stephenson, 1973) monitored  septic tank wastewater
 disposal system effluent migration  in soil and groundwater adja-
 cent  to  the system  in an area of silt and loam overlying glacial
 outwash  sand and  gravel in Wisconsin.   They concluded that soil
 at the site removed essentially all of  the phosphorus present in
 the septic  tank effluent.
      Dudley and Stephenson (1973) monitored migration of phospho-
 rus from septic tank  effluents at 11 sites in central and northern
 Wisconsin.  Efficient P reduction was accomplished at the septic
 tank  system at Site 1 (built in 1968 on the shore of an oligotro-
 phic  lake in outwash  sand  where the depth to the water table was
 3.4- m) as evidenced by generally low total P concentrations at
 wells downgradient from the tile field.   When absorption field
 effluent was sampled concomitant with observation wells about
 4.6 m downgradient,  99.1 to 99.9 percent P removal was found
 resulting in well concentrations of 0.3 and 0.04 mg/1 P, respec-
 tively.
     Dudley and Stephenson (1973) also found very effective P
 reduction at their second  site, a dry well system in outwash sand
 built in 1965.   Depth to the water table was 4 m.   No concentra-
 tions greater than 0.65 mg/1 P were found associated with this
 area.   Effective P reduction at Site 3,  in medium sandy soil,
was evidenced by the fact that concentrations of total P rarely
                                                     »
 exceeded 0.3 mg/1 in wells monitored adjacent to the absorption
 field.  Concentrations within 12 m of the absorption field were
generally in the several hundredths of a mg/1 range.   That system
was built in 1971; depth to the water table was  about 3  m.   The
 same degree of decrease was found at Site 4,  built in 1969 in
outwash sands,  where depth to the water  table was  about  2.5m.
                               11

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     Dudley and Stephenson (1973)  found that their Site 5 septic
tank (constructed in 1970) in an area of sandy loam overlying me-
dium sand where depth to the groundwater ranged from 0.6-6.4  m con-
tained high phosphorus concentrations up groundwater gradient
from the septic tank system due to natural enrichments through
nutrient flushing of organic lake bottom sediments located up-
gradient.  The single down groundwater gradient observation well,
9 m from the tile field, however,  contained only 0.03 to 0.11
mg/1 P during the study period, demonstrating effective P reduc-
tions from percolating effluent.
     Data from Sites 6 and 7 (in clayey sand soil), according to
Dudley and Stephenson, were difficult to interpret due to sampling
difficulties and differences in sampling techniques.  Those sep-
tic tank systems were built in 1968 and 1964, respectively.  Low
levels of P in the pumped wells at Site 7 where depth to the
groundwater was 1-2 m did indicate a decrease in phosphorus from
the effluent, however.  Groundwater directly below the absorption
field at Site 8 (apparently medium sand) showed some transport
of phosphorus and migration of P in the groundwater.  This phos-
phorus would likely not affect water quality in the nearby lake
since the movement of groundwater was away from the lake at that
point.
     As monitored at Site 8 well points located approximately
0.9 m on either side of the absorption field, there was generally
some lateral movement of P in the groundwater.  Concentrations
ranging from about the same to 35 times greater than background
levels were found in these wells.  The most elevated P concentra-
tions were found at. the well site about 3 m from the end of the
tile field.  This well was located on the downgradient edge of the
septic tank.  It is possible that the very high groundwater P
concentrations at that well site were the result of leakage of
the septic tank itself, rather than from tile field drainage.
     Data from Site 9, in outwash sands where depth to the water
table was 3-7 m, showed P contamination in the well about  0.9 m
downgradient from the dry well  (built in 1967).  As was pointed
out by Dudley and Stephenson  (1973) this may be due in major part
                                 12

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 to  system design.   Such  a  system  is  installed  in coarse sand so
 that  lateral  flow  in the unsaturated zone  in response to soil
 moisture  tension would be  minimal.   This coarse sand and gravel
 substrate apparently had little or no ability  to adsorb P during
 the downward  percolation of the effluent.
      Site 10, also a dry well  system, built in 1969 in a sandy
 soil  where the depth to  the water table was  0.6-4  m , demonstrated
 effective reduction of P from  the effluent.  This was evidenced
 by  low levels of phosphorus in the well located several feet down-
 gradient  from the  dry well and in those outside the gravel fill
 area.
      The  final site in the Dudley and Stephenson study was an
 absorption field built in  1974 on about 17 m of unsaturated
 outwash sand.  Due  to differences in sampling  technique, the use
 of  the phosphate data generated was  limited.   Of six sets of sam-
 ples  collected at the two  downgradient wells,  four sets showed
 higher total P concentrations  at the well  immediately downgradient
 from  the  field than at the well about 9 m  farther  downgradient
 This  indicates that there  was  some P reduction occurring.
      Periodic occurrence of elevated phosphorus levels in up-
 gradient wells at a few  of the sites pointed to some local re-
 versals of gradient near the center of the groundwater mound at
 the discharge.  Two of those sites, however, were recharged by
 lake water which may have  contributed to the higher upgradient
 concentrations.
      It was demonstrated in this study that although phosphorus
 enrichment of groundwater  occurred in a few coarse sand systems,
 effective decreases in phosphorus took place in medium and fine
 sand  soils.  In most sites monitored, low total P concentrations
were found in well stations 4.6 m  downgradient from input,  and
beyond.
     Viraghavan and Warnock (1976b)  studied migration  of phos-
phorus from an experimental tile field in sandy loam,  silt loam
to silty clay, loam soil in Ottawa,  Canada.  One sample set  showed
apparently effective P removal by a point  9.1m  from  the

                               13

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experimental tile field.   It appeared from diagrams presented that
concentrations in wells beyond that point could have been influ-
enced by flow from laterals of the main septic system adjacent to
the experimental field.  Although Viraghavan and Warnock concluded
that the decrease of phosphate achieved in this study was not high,
it was difficult to determine patterns of removal from the data
presented.
     Reneau and Pettry (1976) conducted a study during 1972-1974
in Chesterfield County, Virginia on Goldsboro sandy loam and
Varina sandy loam to determine effects of septic tank effluent
on soil P fractions and their distribution.  Both soil areas were
moderately well drained and had seasonally perched water tables.
The system on Varina soil had been in use for approximately 15
years, receiving an estimated 2700 I/day effluent.  The  system in
the Goldsboro soil was four years old and received an estimated
770 I/day effluent,
     Data from 46 groundwater samples adjacent to the drainfields
in Varina soil indicated that dissolved P consisted primarily of
soluble ortho P with only minor contributions from polyphosphates
and organic P.  In the Varina soil, increased concentrations were
found at the  89-99 cm  depth.  Soluble orthophosphate concentra-
tions at that depth showed a decrease from an average effluent
concentration of  5.5 mg/1 to an average of 1.05 mg/1 at  0.15 m
from the drainfield, an  80 percent P reduction.  This decrease
generally continued with distance  from the drainfield.   At  6.1m
from the drainfield, greater than  90 percent reduction in average
soluble ortho P was found.  By 12  m from the discharge,  the  con-
centration  was an average of 0.01  mg/1 P, a 99 percent removal of
phosphate.  Using the  maximum concentrations found  at the 89-99
cm depth  12 m from the drainfield, removal was  80  percent.   Con-
centrations in the lower, plinthic horizon  (all averaged at  or
below  0.01  mg/1  P) according to Reneau and Pettry,  showed that
that horizon  was  an effective barrier to vertical  soluble ortho  P
movement.   Mo detectable soluble  ortho P was  found in perched
water  tables  not  receiving  septic tank effluent.

                               14

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      An examination of P fractions in the Varina soil horizons
 at different depths downgradient from the drainfield area showed
 increased concentrations,  as compared to the control profile,  of
 all fractions in the top 18  cm at 0.15 m from the drainfield.
 Reneau and Pettry attributed this to previous fertilization  prac-
 tices.   Phosphorus concentrations at 0.15 m from the drainfield
 reached a maximum in the B21t and B22t horizons  (41-76  cm depth)
 and decreased rapidly in the plinthic horizon (beyond 76  cm
 depth).   The accumulation  of P from septic tank  effluent,  they
 concluded,  was concentrated  in the argillic horizons.   The in-
 crease  in "fixed"  P in that  horizon at 0.15 m reflects  not only
 water movement in  a horizontal direction above the plinthic  hori-
 zon,  but  also the  influence  of soil physical and chemical  proper-
 ties  of these horizons on  P  fixation.   At  3  m from the  drainfield
 in  the  B21t and B22t horizons,  there  was  essentially no difference
 in  P  fractions from those  found  in the central profile.
      At the Goldsboro location,  soluble ortho P  was  present  pri-
 marily at the 142-152  cm sampling  depth.   From an average  drain-
 line  concentration  of 11.8 mg/1  P,  average  concentrations  were
 decreased 92  percent  by  0.15 m from the tile  field.   Concentra-
 tions generally decreased  at that  depth with  increasing distance
 from  the field.  At  3  meters from  the  tile  field, there had been
 a reduction of  98 percent, to  an average of  0.21 mg  P/l.   On the
 average, there  was no  detectable phosphate at  this depth,  13.5 m
 from  the drainfield.   Maximum  concentrations there were 0.01 mg
 P/l.  In the  Goldsboro soil, the septic tank effluent generally
had little  influence on  soil P fractions at 0.15 m.  This was
attributed  to the youth and limited use of the system.
     Reneau and  Pettry stated that during periods of lower water
tables at the Goldsboro site, soluble ortho P apparently moved
primarily in a  vertical direction in the saturated zone below
the drainlines until the perched water table or restricting layer
was intersected.  Horizontal movement then occurred at the 142-
152 cm depth.  There was no indication that the phosphate moved
into the 432 cm depth which was in the permanent groundwater  table.

                                15

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     Smith and Myott (1975) reported that 57 percent of the 1.5
million people in Nassau County, N.Y. were served by sewers.   The
remaining population discharged  230x. 106 I/day sewage 'into the
ground. They undertook a study to determine constituents of sewage
origin in groundwater during 1971 and 1972.  It indicated that the
elevated levels of phosphorus (0-10 mg P/l) attributed to cesspool
leachate  were found in shallow observation wells but not in the
selected Magothy aquifer wells beneath the more shallow aquifer.
     Beek ejt al. (1977a) conducted a two-year study on a sewage
farm drainfield on sandy soil near Tilburg, the Netherlands.
This farm had been in use for 50 years during which time the
drainfield was intermittently flooded (generally once a month).
Averaged over the two-year monitoring period, they found removal
of total and orthophosphates up to 96 percent between sewage water
and field drainage water.  They found that the accumulation of soil
phosphates was limited to the top 50 cm soil layers; nonflood soils
showed low levels of soil phosphate in the top 75 cm of soil com-
pared with flooded soil.  Adsorption reactions were proposed at
the mechanisms involved, because of the high efficiency of phos-
phate removal despite limited contact with the soil.
     Comparison of the chemical forms in which phosphates accumu-
lated in sandy soil plots flooded intermittently for 30 years and
for 50 years was made by Beek et_ al. (1977b).  They showed that
the distribution patterns of the different phosphate fractions
were virtually the same in both plots.  Because of this, in ad-
dition to the fact that the Al-combined phosphates prevailed, it
was concluded that phosphate retention in  these soils was still
mainly governed by reactions with aluminum.  The presence of ac-
tive Al compounds, either available  in the soil system prior to
flooding or added as components of  sewage  water, according to
Beek ejt al., will determine the ultimate storage capacity of the
soil for phosphate binding in that  soil.
     Lee  (1976a)  studied the groundwater transport of nutrients
 (N and P) to Lake Sallie located in glacial  outwash terrain of
west central Minnesota.  Evaluation of the contributions of

                                 16

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 nitrogen  and phosphorus was based on groundwater samples collected
 using  seepage meters placed on the lake bottom  (7 to 17 m from
 shore) adjacent to a residential and/or cropland area.  Lee con-
 cluded that the contribution of phosphorus from groundwater in-
 cluding septic tanks near the lake was insignificant compared to
 the  surface water phosphorus load.
     It is concluded from these field studies on transport of
 phosphorus from septic tank wastewater system effluents that the
 likelihood of significant transport is small.  Several other in-
 vestigators who have reviewed this topic have reached similar
 conclusions.  According to Okun (1972), in unsewered areas, which
 include about 30 percent of the total US population, although
 waters from the wastewater disposal systems may reach lakes and
 streams,  the phosphates are held in the ground.  He concluded
 that private sewage disposal systems are of little consequence
 to the eutrophication problems of the US.
     Corey et al. (1967) estimated principal sources of phosphorus
 for Lake  Mendota, Wisconsin.  The contributions from private sew-
 age systems (septic systems) were estimated by assuming that 5
 percent of the phosphorus in the sewage eventually reaches sur-
 face waters.  Corey et al. estimated that septic tank wastewater
 disposal  systems contributed a minor fraction (2 percent) of the
 total phosphorus input.
     It has been estimated that private sewage systems contributed
 2.2 percent of the phosphorus load to surface waters of Wisconsin
 (Wirth and Hill, 1967).  This contribution figure was based on
 the assumptions that all nutrients contributed by private sewage
 systems reached surface waters and that the systems were used
 year-round.  They stated that not all systems were located in
 close proximity to surface waters and that it was  likely  that two-
 thirds or more of the septic systems on water front properties
 are not used for more than three or four months per year ,
Therefore, it is unlikely that septic tank wastewater disposal
 systems would represent significant sources of phosphorus that
 could contribute to the excessive fertilization of surface waters.

                               17

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SUMMARY AND CONCLUSIONS FROM LITERATURE
     It has been demonstrated by previous studies that the poten-
tial of a soil to remove phosphate from septic tank wastewater
disposal system effluent is controlled by the mineralogy of the
area soils, rather than by the soil particle size.  In field
studies, it was found that most soils, even medium sandy soils,
exhibit substantial ability to reduce phosphate concentrations.
Reductions found were typically in excess of 95 percent within
relatively short distances from effluent sources.  It has also
been shown that the capacity of a soil to reduce effluent phos-
phorus concentrations is not necessarily finite.
     It can be concluded, based on these studies, that it is un-
likely that, under most circumstances, sufficient available phos-
phate would be transported from septic tank wastewater disposal
systems to significantly contribute to the excessive aquatic
plant growth problems in water courses recharged by these waters
                                18

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                             SECTION  4
       EXPERIMENTAL  PROCEDURES AND  CHARACTERISTICS  OF AREA

      To  determine soil  characteristics,  groundwater flow patterns,
 and  general  groundwater quality  in the study  area, 18 test wells
 were installed  (by  Stephenson) in  July,  1970.   Figure 1 shows
 the  locations of these  wells as  well as  those already present in
 the  area.  All  test holes were drilled to  3 meters or greater be-
 low  the  water table elevation found  on the date of drilling.  Sand
 point  piezometers (3.21  cm diameter)  were installed in  each  test
 hole to  provide a continuing capability  for measuring the ground-
 water  evaluation.
     In  an effort to evaluate potential /phosphate transport in  the
 development  area  several preliminary sorption  tests were run on
 area soil samples provided by Owen Ayres £ Associates.  Analyses
 were made by taking approximately two grams of  the sample pro-
 vided, placing  it in a  300 ml flask  to which  100 ml of a 10 mg  P/l
 solution was added.  Each flask  was  capped and  shaken for 24 hours.
 At the end of this  period, each  sample was filtered through a
 0.4-5 micron  pore size membrane filter that had  been pre-washed
 with distilled water.   The phosphate content of the filtered solu-
 tion was determined by  the phosphomolybdate method (APHA et_ al.,
 1965).  Blanks were carried through the tests to compensate for
 losses due to sorption  of phosphorus on glass during filtration,
 etc.   The amount of phosphate lost to the sand was determined by
 subtracting the phosphate concentration remaining in the solution
 after contact with the  sand from the initial phosphate solution
 added to the sandy mixture.   The phosphate sorbed per gram of sand
was determined by dividing the amount of the phosphate  uptake by
the weight of sand used in the particular study.  Each  sample was
run in duplicate.
                                19

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                     Figure I
         Location of Hydrologic Test Wells
         Voyager  Village Development Area
                 Scale: I cm* 0.6km
After Stephenson  (1971).
                        20

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      To obtain an estimate of the surface water quality at the
 outset of the study, grab samples were collected from lakes and
 streams in the area on June 9, 1970.   About a month later, select-
 ed wells shown in Figure 1 also were  sampled.  Phosphate analyses
 were carried out in accordance with the phosphomolybdate method
 (APHA et al. , 1965).
      After the direction and general  velocity of the groundwater
 had been defined by Stephenson (1971), a septic tank effluent
 monitoring program was established.   An existing septic tank sys-
 tem in the vicinity of wells 3 to 7 (an area to be  serviced by
 septic tank systems in conjunction with the Voyager Village de-
 velopment) was chosen for monitoring.   Observation  wells were
 placed as shown in Figure 2.  Wells A-J were installed at a depth
 of 1.5 m below the water table;  wells  K,  L and M to U.6 m below
 the water table.   Later, during  the study,  two additional wells,
 N  and 0,  were drilled also to a  point  1.5 m below the  water table.
      Wells A-M were sampled on the following dates:   February  3,
 February 16, April 17,  August 29  and October 29,  1972;  January 25
 and July 26, 1973;  October 10, 197U; and January  15,  1976.   On
 October 10,  1974  and January 15,  1976,  wells N and  0 were also
 sampled.
      Although the analysis program was  occasionally altered dur-
 ing the course of the study,  the  following  parameters were
 generally  measured:   specific conductance, pH, alkalinity, Na  ,
 Cl~,  K , Mg   ,  Ca   ,  soluble orthophosphate, total phosphorus,
         ,  and  organic N.   Phosphate analyses were carried out in
accordance with the phosphomolybdate method (APHA et al. , 1965;
APHA e_t al . , 1971; APHA et al. , 1976) or equivalent.  Elevated
chloride and specific conductance values are good indicators of
the presence and movement of septic tank effluent in groundwater.
The alkalinity, calcium and magnesium concentrations can provide
general information regarding direction of effluent flow in the
groundwater but are usually not as useful as chloride and specific
conductance values in this regard.  The sodium concentrations
should generally follow the chloride concentrations although they
                               21

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                      Figure 2
            Test Wells for Septic Tank
                 Monitoring  Study
          Voyager Village Development Site
                 Scale: Icm = 7.6  m
                          J
             M                          2

              *'                   6
                         B
  • 'WELL POINT

                       groundwater
After Huff and Stephenson  (1971)
                          22

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 are not usually as  sensitive to  changes in concentrations result-
 ing from  contamination by  septic tank effluent.  The potassium
 and sulfate values  are useful in this study only in terms of
 characterizing the  general content of the groundwater.  Neither
 measurement can be  interpreted in a way as to contribute to the
 overall objectives  of this study.  Turbidity can give an indica-
 tion of the amount  of suspended  solids not purged from the well
 prior to  sample collection.
     As the focus of this study  is on the transport of aquatic
 plant nutrients, especially phosphorus, of primary interest are
 the concentrations  of soluble orthophosphate, nitrate and ammonium.
 Total P and organic N concentrations have little meaning in this
 groundwater study as they do not give an indication of available
 forms of  aquatic plant nutrients that are allowed to pass through
 the groundwater to  potentially influence surface water quality.

 CLIMATE
     According to Blackman ejt al. (1966), the climate of the area
 (Burnett  County, located in northwest Wisconsin) is continental.
 Mean temperatures drop below freezing in mid-November and freezing
 of lakes  follows soon after.   The average date of the first freeze
 in the fall is September 12;  the average last freeze in spring is
 May 31.   The average annual precipitation for Burnett County is
 about 78  cm.  The average runoff is 24 cm near Rush City on the
 St. Croix River.  Maximum precipitation occurs in June; however,
highest runoff usually occurs during April in association with
 snowmelt.
     The original vegetation  of the southern farm area in the
 southern part of the county was oak or pine,  but the second growth
timber is largely white birch and aspen.

QUALITATIVE DESCRIPTION OF SOILS  AND GEOLOGY
     N.E.  Isaacson 6 Associates,  Inc.  began an investigation of
the hydrologic  and hydrogeologic characteristics of the Voyager
Village development area in April,  1970.   These studies were

                                23

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conducted by Stephenson (1971) and Huff and Stephenson (1971).   They
found that stratified sandy soil deposits, mostly glacial drift
outwash, characterized the area.  The deposits were products of
glacial melt-water stream deposition which occurred in recent
geologic time.  Deposits of the last glacial episode were subse-
quently covered by younger outwash containing large, melting ice
blocks.  The hummocky topography of the area was created as the
buried ice blocks melted.
     The glacial drift deposits are a fine to medium grained sand;
mean grain size diameter was 0.125 to 0.5 mm.  The sand deposits
could generally be vertically zoned into two rather distinct and
recurring units:
     1.  Sand;  dark red brown; fine- to medium-grained;
         sometimes silty; generally 3 to 9 m thick;
                                                 2
         permeability ranges from 0.4 to 1.2 I/cm /day.
                         -overlying-
     2.  Sand:  light red brown; medium- to coarse-grained;
         	                                  2
         permeability ranges from 1.2 to 4 I/cm /day;
         thickness unknown but estimated at maximum of
         46 m.
Stephenson (1971) indicated that these layers likely overlaid a
crystalline bedrock composed of granite-like Precambrian rocks.
     Table 1 presents representative grain size characteristics
for selected and representative samples taken at or near the
water table elevation within three of the wells.   The predominant
sand grain size at or near the water table was within the medium
grain range, 0.25 to 0.5 mm diameter.   The water table occurred
in either of the two vertical soil zones described, depending on
the location within the development area.  According to Huff and
Stephenson (1971) the water table was generally within the upper,
finer-grained soil east of Shoal and Cadotte Lakes and within the
lower, coarser-grained sands west of that position.  They attrib-
uted this to the coincidence of the mean water table level in the
Shoal and Cadotte Lakes are  (299-300 m elevation)  with the
average elevation of the fine/coarse-grained sand boundary (299_
1.5 m elevation),

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                                 TABLE 1
           SIEVE ANALYSES ON SELECTED SAMPLES-VOYAGER VILLAGE,
                             BURNETT COUNTY
Sieve


10
16
40
60
80
<80


mesh
mesh
mesh
mesh
mesh
mesh
Size


(2
(1
(0
(0
(0
(0


mm)*
.2 mm)
.42 mm)
.25 mm)
.15 mm)
.15 mm)
TOTALS
Well
Weight
gms
28
228
820
788
185
96
2145
No.
2
Percent
Total
1
10
38
36
8
4
100
.31
.63
.29
.74
.62
.48
.07
Well No.
We ight
gms
27
219
1240
379
153
101
2119
3
Percent
Total
1
10
58
17
7
4
100
.27
.34
.52
.89
.22
.77
.01
Well No. 6
We ight
gms
__
0.5
17
375
489
179
1061
Percent
Total
_—
0.05
1.60
35.34
46.09
16.87
99.95
*Wentworth Scale for sand:
    very coarse-grained
    coarse-grained
    medium-grained
    fine-grained
    very fine-grained
 Dash (—) indicates no contribution made from that fraction.
1.0 - 2.0 mm
0.5 - 1.0 mm
0.25 -0.5 mm
0.125 - 0.25 mm
0.0625 - 0.125 mm
                                    25

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     Stephenson (1971)  noted a soil composition change which oc-
curred along the approximate line A-A'  shown in Figure 1.   North-
east of this line, soils were sandy as  previously described.   To
the southwest, the soil matrix was siltier;  however,  gravel per-
centages were found to  increase.   Gravel was scarce over much of
the northeastern area.   According to Stephenson, there appeared to
have been a relationship between the soil differences and dif-
ferences in surface water character; Bartash Lake had soft water
and was non-calcareous.  The surface waters  to the northeast ap-
peared to be hard waters.

SORPTION TESTS
     The results of phosphate sorption tests run on the soils of
the study area are presented in Table 2.  Examination of this
data shows that the various samples sorbed from 1 to 5 mg.P/100 g
soil in 24 hours.  This amount of sorption is small when compared
to what would be expected in typical clay soils.  Various clay
mineral soils have been found to sorb,  at neutral pH, from 0.03
to 0.07 millimoles phosphorus per gram solid (93 to 217 mg P/100  g
solid) at equilibrium  (Grim, 1953).  Although the behavior
of various types of natural soils from other areas under the par-
ticular test conditions used was not generally known, the results
of the Voyager Village development area soil tests tended to show low
short-term sorption capacity.  However, tests of this type do not
adequately measure long-term sorption and precipitation such as
that associated with hydroxyapatite formation.  Comparison of the
sorption values with the sorption maxima reported in Tofflemire
et al.  (1973) and Ellis and Erickson (1969a) shows that the amounts
of P sorbed by these samples  (1 to  5 mg P/100 g) were at the lower
end of the range of maximum sorption reported in the literature
(2 to 49 mg P/100 g).   If higher concentrations had been incor-
porated in this testing, it is likely that  greater sorption capac-
ity would have been found.
                                 26

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                     TABLE 2
        PHOSPHATE  SORPTION TESTS  ON  THE
      VOYAGER VILLAGE DEVELOPMENT AREA SOIL
           (sorption  time - 24 hours)
Well Number*
6
6
9
9
17
17
18
18
24
24
38
38
mg P/100 g solid
2.2
1.2
4.0
4.3
3.4
1.9
4.0
3.1
2.8
2.1
3.4
5.0
*Numbers do not necessarily correspond to well
 numbers.
Samples provided by Owen Ayres 6 Associates.
                       27

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HYDROLOGY AND WATER QUALITY

     Available water table and surface water elevations for Octo-
ber, 1970 as presented by Stephenson (1971) are shown in Figure 3
and indicate that the groundwater in the Voyager Village develop-
ment area moved from the southeast to the northwest.  According to
Stephenson (1971) surface water movement was also in this direc-
tion, toward the St. Croix River.  Estimated permeability values
in the sand layers at the wells averaged from 1.2 to 2.4 I/cm /day
(Huff and Stephenson, 1971).  The recharge for the development
area groundwater appeared to be southeast of Birch Island Lake.
     Drainage systems in recently glaciated regions are not always
well developed.  As a result, according to Huff and Stephenson
(1971), perched and/or otherwise isolated surface water bodies are
not uncommon.  The unnamed lake to the west of well 13 appeared to
be perched 7.6 to 9.1 m above the water table.  Huff and Stephenson
noted that this fact may account for its apparently more advanced
eutrophic state relative to other area lakes.
     In general, groundwater in the development area was found to
move in a simple flow pattern.  The surface topography of the
area apparently had no influence on the direction of groundwater
movement.  According to Huff and Stephenson (1971), this appeared
to be true both for the different.seasons and for different con-
ditions.  For most, if not all lakes within the Voyager Village
development boundaries, groundwater entered lakes from the east
and southeast perimeter and re-entered the groundwater system along
the west and northwest perimeters of the lakes.

 Groundwater Velocity
      As  discussed  by  Stephenson  (1971),  the water  table  gradient
 for that portion of the  development  area between Birch Island  and
 Shoal-Cadotte  Lakes would be  one m per 1000 m.  An estimate of
 groundwater flow volume  per m width  of flow  path in 46 m of soil
 was between 242  and 2019  I/day.   The 242 I/day estimate  was for
 the development  between  Birch Island and Shoal-Cadotte Lakes.
 Groundwater velocities were calculated to range from 0.15  to
                                 28

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                      Figure 3
             Groundwater Flow Pattern
           Voyager Village Development Site
    Water Table Elevations on October 17 and 21,1970
       Lake  Surface Elevations on October 3,1970
       (Elevations in Feet Above Mean Sea Level)
                 Scale: (cm * 0.6km
                                     975
                                                980.
                              _  983*  x
                             :  983     985
                               984
                                    987
                                985
                                       BIRCH ISLAND
                                           LAKE
                          985
After Stephenson  (1971).

Note:  The  units  in this figure were  taken  from the
       original report  (Stephenson,  1971).
                         29

-------
1.2 m/day.   In the area of immediate interest where the septic tank
study was conducted, a velocity of about 0.3 m/day appeared to be
average.
Groundwater Quality

     The 21 wells were sampled once in July, 1970.  The values of
the various physical and chemical parameters measured are presented
in Table 3.  The pH of the various groundwater samples ranged from
6.4 to  7.6.  pH values in this order of magnitude are normally
found in groundwaters and would not cause any water quality prob-
lems.
     Specific conductance values ranged from 64 to 440 umhos/cm
at 21°C.  The majority of the wells had specific conductance values
between 100 to 200  ymhos/cm.  Specific conductance is a measure of
the total amounts of salts in solution.  The contamination of
groundwaters by septic tank effluents will be expected to increase
the total amounts of salts considerably above the levels found in
the wells  sampled.  The high value of 440 for well number 1 is
somewhat surprising since wells  2,  3,-4, 7  and  8  are  located
in the  same general area and all show values which are more in
accord  with what is expected.  The examination of well 1 data
shows that the calcium and alkalinity are also high for this well,
while the  chloride  is about the  same as in the other wells.  The
sodium  is  higher for this well than the others.   It appears that
this well  is  in an  area where the groundwater has had the oppor-
tunity  to  pick up significant amounts of calcium  and  carbonate
species from  the detrital limestone in the region.
     Generally, turbidity values in groundwaters  are  low and  fre-
quently zero  due to the filtration of the particulate matter  by
the  aquifer material.  The high  turbidity values  noted in  some of
the  wells  resulted  from the large amounts of suspended solids
which  arose from the  recent placement of the well points in the
area.   In  order to  make a more realistic assessment of the tur-
bidity levels in the  water, it would  be necessary to  pump  each of
these  wells for a  considerable period  of time.   This  would tend
to clear up and eliminate  the  debris  that is left in  the well
                                 30

-------
                                                                                                 TABLE  3
                                                                  CHEMICAL ANALYSIS OF  THE HELL POINT  SAMPLES FROM VOYAGER VILLAGE PROJECT
                                                                                COLLECTED III  JULY,  1970  BY  D.A.  STEPHENSON
CO
Parameter*
pH
Specific
Conductance
limhos/CM
at 21»C
Turbidity
(JTU)
Na*
Ca**
HO~-N
N1I*-H
Total P
Soluble
ortho P«
Cl~
Fe'soluble"**
Fe total
Alkalinity
1
2
3
7.5 6.G 7.5
mo 101 251
5
12
15.5
50.0
0.7
0.15
0.1
0.007
3.0
0.03
0.05
168
0
1.6
2.5
5.5
0.15
0.15
0.31
0.006
2.5
0.16
0.21
38
11
1.0
6.5
23.0
0.30
0.60
0.08
0.003
12.5
0.01
0.2J
115
M

S

6

WELL POINT NUMBED
7 8 10 11A*"


61 113 265 111 120
19
1.5
2.5
3.0
0.15
0.21
0.06
0.001
2.5
0.07
6.12
29
0
2.0
6.0
7.0
0.08
0.11
0.02
0.001
2.5
0.03
2.63
59
10
5.1
6.5
16.0
0.60
0.02
0.16
0.005
13. S
0.03
0.17
99
11
3,3
5.S
12. S
0.15
0.50
0.13
0.005
5.0
0.03
0.03
70
0
2.3
5.0
7.0
0.07
0.01
0.30
0.001
5.0
0.03
0.82
15

91
17
1.7
1,0
8.0
0.08 1.10
0.03 0.06
0.20 0.12
0.006 0.08
2.0
0.11 0.03
0.98
*5
11B
6.9
118
3.1
8.0
0.17
0.09
0.01
5.5
0.08
15.1
£2
13

97
17
3.0
5.0
0.70
0.12
O.OU
3.0
O.H
5.0
»
11

66
0
2.5
1.0
1.6
0.11
0.16
0.005
3.5
<0.01
1.25
18
IE

18

95 220
15
3.0
5.0
I/O
0.10
0.36
0.001
1.0
0.03
1.10
33
0
7.0
19.0
0.45
0.06
0.77
0.001
15.5
0.07
1.K1
82
19

20

220 110
0
15.5
m.o
0.10
o.os
0.013
2.0
0,03
0.3
178
8
3.5
10,0
0.15
0,12
0.21
0.001
1.0
0.13
0.23
52
21
6.7
97
17
3.0
5.0
1.0
0.30
0.58
0.005
1,5
0.07
2.16
3M
                               *A11  values reported as  «g/l  except  pH,  Specific  Conductance and turbidity.
                              **Soluble defined as passage through  O.MS u pore size Membrane filter.
                             ***Insufficient sample collected  for complete analysis.
                             Many of the samples collected contained large amounts of  suspended solids that arose from
                             the drilling of the well points.  These turbidity, total iron  and  total phosphate values
                             are expected to be much larger  than normally found  in groundwaters as a result of this
                             contaminat ion.

-------
immediately after placement.   No attempt should be made to judge
any change in water quality based on changes in turbidity from
those reported at this sampling.
     The sodium values ranged from 1.5 mg/1 to about 12 mg/1 with
the typical values on the order of 2 to 5 mg/1.  These values are
normal for groundwaters of the area.  The 1970 levels of sodium in
the groundwater do not represent any adverse effect on water qual-
ity.  It would be expected that large increases in the amount of
sodium in the groundwaters would occur as a result of the contami-
nation of the aquifer by septic tank effluent.
     The magnesium values ranged from 2.5 to 15.5 mg/1.  These
values indicate that, in general, the aquifer material has a low
limestone content and the waters derived from it would be classi-
fied as soft waters.
     The calcium values ranged  from 3 to 50 mg/1.  The majority of
the values ranged from 3 to 15  mg/1.  The only exceptions to these
values were well numbers 1 and  19.  The high values at well num-
bers 1 and 19 indicate that these wells are  in small pockets of
calcareous material.  This observation is supported by the fact
that these two stations have relatively high alkalinities which
indicate that the high calcium  arises from  the dissolution of
calcium carbonate in the aquifer.
     Nitrate derived from ammonium  is one of the  constituents of
septic tank effluent which affects  groundwaters.  All  of the ni-
trate values for the wells sampled  were less than 2 mg/1 nitrate-
N.  Concentrations of this magnitude are typically found in ground-
waters.  Concentrations of 10 mg/1  N are considered to be exces-
sive and would cause the water  to be rejected  for water  supply
purposes.  However, in-lake concentrations  in  excess of  approxi-
mately  0.3 mg/1  nitrate-N are of concern and would tend  to produce
excessive  growths of algae and  aquatic  plants  in  the lake if
other constituents necessary  for growth were present in  adequate
amounts.   Septic tank effluent  will likely  lead to increased  con-
centrations  of nitrate in groundwaters.  This  could further ag-
gravate the  problems  caused by  excessive fertilization of lakes

                                32

-------
 if  the  septic tank  effluent  flowed through the groundwater into
 the lakes, and if the lake system is nitrogen limited.  Fortunately,
 there are a number  of chemical and biochemical reactions that tend
 to reduce nitrate concentrations in some groundwaters.  These re-
 actions will tend to minimize the nitrate problems in some areas.
 However, the understanding of these reactions is such that it is
 impossible to predict without extensive study whether or not ni-
 trate may be a problem as a result of contamination of groundwaters
 by septic tank effluent.  It appears from Table U that a compari-
 son of available nitrogen and phosphorus concentrations shows
 that nitrogen may be the limiting nutrient in at least some of
 the area lakes.  Therefore, groundwater nitrate may be a problem
 in influencing algal growth in surface waters.
     Generally, groundwaters have very low concentrations of am-
 monium since this chemical species tends to be sorbed onto soil
 particles.  As indicated by ammonium concentrations in excess of
 0.1 mg/1 N, the aquifer materials of this area likely have a low
 sorption capacity for ammonium.  The concentrations found in these
 wells would generally present no significant water quality prob-
 lems for domestic use.  However, when ammonium concentrations in
 groundwater discharging into a lake are greater than 0.3 mg/1 N,
 a potential for increasing the fertility of the lake exists since
 ammonium in addition to nitrate is readily available for algal
 growth.
     The total phosphorus concentrations found in these wells are
 not generally characteristic of the groundwaters since they rep-
 resent the phosphorus associated with the high turbidity (sus-
 pended solids) which resulted from the recent placement of the
wells relative to the well sampling.   Normally,  one would expect
 to find little total phosphorus in the aquifer and any phosphorus
that is  found would probably be in a soluble orthophosphate form.
     Nearly all the values for soluble orthophosphate are less
than the critical levels of 0.01 mg P/l that have frequently been
 found to cause excessive growths of algae and other waterweeds in
lakes.   The one exception was well 11A which had been found to

                                33

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                             TABLE  4
               CHEMICAL ANALYSIS  OF  SURFACE WATERS  IN
                  VOYAGER  VILLAGE DEVELOPMENT AREA
                          (June 9, 1970)
Bartash
Parameter Lake
Specific
Conductance
Vmhos/cm @ 22°C
pH
NH^-N
NO^-N
Organic-N
Soluble ortho P*
Total P
Aklalinity as
CaC03


26
7.2
0.04
< 0.02
0.52
0.006
0.032

2.2
LOCATION
Outlet Little Culbertson
Loon Bear Creek-Spring
Lake Lake Outlet


110
8.8
0.04
0.04
0.36
0.086
0.364

50.0


100
8,2
0.04
0.04
0.55
0,143
0.556

48.0


148
9.1
0.02
0.06
0.3
0.098
0.408

74.3
Loon Creek
at Loon
Creek Trail


147
8.1
0.06
0.06
1.1
0.264
0.574

54.5
^Soluble is defined by passage through a 0.45 y pore size membrane
 filter.
All values reported as mg/1 except Specific Conductance and pH,
                                 34

-------
 contain 0.08  mg  P/l  soluble  orthophosphate.   It  is  likely  that
 this  sample was  contaminated as  it  contained  large  amounts of sus-
 pended solids and there  was  insufficient  liquid  available  to per-
 form  the complete set  of analyses on  it.  Based  on  the previous
 studies conducted on the sorption capacity of the aquifer  mate-
 rials from this  area,  it is  reasonable to conclude  that .surface-
 water contamination  problems could  result from the  use of  septic
 tank  wastewater  disposal systems in this  area, provided that the
 contaminated  groundwaters reach  a lake or stream.   Normally, phos-
 phate is not  transported to  any  degree in aquifers  which are high
 in  calcium carbonate,  due to the interaction  of  the phosphate
 with  the calcium.  Therefore,  in the  areas where high alkalinity
 and hardness  were noted,  lesser  phosphate transport will be ex-
 pected.
      The chloride levels found in the various wells ranged from
 2 to  15.5  mg/1.   These levels  would not cause any water quality
 problems.  The discharge of  septic  tank effluents to groundwaters
 will  result in a large increase  in  the chloride  content of these
 waters.   Chloride is one of  the  chemical  parameters that is a
 useful indicator of  the  contamination of  groundwaters by septic
 tank  effluents.
     The total iron represents the iron that is primarilv from the
 contamination of some of the water samples by the well point driving
 operations.  The soluble iron represents that iron that would  pass
 through a  0.45 micron pore size filter and is probably,  in this
 case,  iron that is in a very finely divided particulate form.   The
 iron present may aid  in the removal of phosphorus from the ef-
 fluents .
     The alkalinity values ranged from about 30 to 180 mg/1 as
 calcium carbonate.  The alkalinity values  parallel the calcium
 and magnesium values.  The high alkalinity values reflect  the  fact
that some parts of the  aquifer are  somewhat  calcareous.
     From an overall point of view,  the groundwaters in  the Voyager
Village development area were of  high  quality at  the onset  of  the
study.
                                 35

-------
Surface Water Quality

     In order to assess general surface water quality in the Voy-
ager Village development area before development, grab samples
of water were collected from the lakes and streams in the area.
The values of general physical and chemical parameters measured
in the surface waters are presented in Table M-.  At the time of
year that samples were collected, relatively low concentrations
of nitrate, ammonium and soluble orthophosphate will likely be
present in surface waters as a result of uptake by aquatic plants.
Consideration, therefore, must be given to the total phosphorus
and organic nitrogen concentrations.  These values reflect to a
degree the amounts of potentially available nutrients present
within algal cells which would become available upon the death
of the plants.
     Bartash Lake is a soft water, seepage lake of high water
quality.  It had a very low specific conductance of 26 ymhos/cm
@ 22°C.  The alkalinity in this lake was 2.2 mg/1 as CaCO~.  The
                                                         O
aquatic plant nutrient concentrations found on the date of sam-
pling were generally low.  The only well drilled near Bartash
Lake is number 21.  Comparison of the water quality between this
well  (Table  3) and the lake shows that there was little relation-
ship between the two.  Water taken from well 21 had a much greater
alkalinity and greater specific conductance than that of the lake.
     Loon Lake is a hardwater seepage lake adjoining Cadotte Lake.
The north end of the lake on the date of sampling had thick
aquatic vegetation and a few areas of floating bog.  Based on the
high pH and high total P concentration, it would appear that on
the date of sampling, this was a highly productive lake.  The
wells located near Cadotte and Loon Lakes (Table 3) had alka-
linity and specific conductance values which were similar to, al-
though not the same as, the lake water.
     Little Bear Lake is a hardwater seepage lake containing high
concentrations of phosphorus and a relatively high organic N con-
centration.  This would indicate a fertile water body.  Well 20,
located on the north side of the lake, had a general chemical com-
                                36

-------
position similar to that of the lake.  This would be expected
since this well was in the general direction of groundwater flow.
     Culbertson Creek appeared to be a hardwater stream contain-
ing relatively high concentrations of aquatic plant nutrients.
Wells 13 and 19 in the Culbertson Creek area had respectively low-
er and higher specific conductance and alkalinity than the creek.
Look Creek at Look Creek Trail is a hardwater stream containing
the highest concentrations of both nitrogen and phosphorus com-
pounds of the lakes and streams sampled.
     From an overall point of view, except for Bartash Lake,  all
of the other lakes and streams in the development area seemed to
be experiencing excessive aquatic plant fertilization in the  ab-
sence of any development in the area.
                               37

-------
                           SECTION  5
                            RESULTS

SEPTIC TANK USE
     The septic tank-tile field wastewater disposal system moni-
tored for this part of the study went into operation on May 20,
1971 serving a middle-aged couple.   This couple resided on the
property for nine months each year  during the spring, summer and
fall.  They used an automatic washer with cold water All detergent.
There was no garbage disposal in use, but a dishwasher was instal-
led in May, 1973 (Carlson, 1973).
OBSERVATION WELL MONITORING
     The first water samples were collected from wells A-M (see
Figure 2) on February 3, 1972.  The results of the analyses made
on these samples are presented in Table 5.  Slightly higher
chloride values were found at several wells (I, J, L, M), but not
at wells immediately down groundwater gradient from the tile
field.  This pattern appeared to be related both to the fact
that the residence was not occupied during the winter months and
that the septic tank had been installed only eight months prior
to sampling.   Of the four wells that showed elevated Cl" concen-
trations, two  of them were the deeper wells.  Higher calcium
concentrations were found in the deeper wells and could generally
be related  to  higher alkalinity values  there.   In  these measure-
ments,  as well as  subsequent measurements, elevated  concentrations
of alkalinity and,  in many cases,  calcium were  observed in wells
directly down groundwater gradient from the tile field.  In some
instances,  such as  on the February 3 sampling,  and  in  some subse-
quent  samplings, the  increased  alkalinity and calcium  were not
accompanied by an  increase in  chloride.   However,  increases in
                                 38

-------
CD
                                                           TABLE 5
                             VOYAGER VILLAGE SEPTIC TANK MONITORING STUDY OBSERVATION WELL DATA
                                                     (February 3, 1972)
Parameter
Specific
Conductance
Umhos/crn @ 20°C
PH
11*
Ca"
Mg+t
Alkalinity
as CaCO,
so;
Soluble ortho P
Total P
U
NO~-N
Organic N-N
A
48
6.2
0.5
1.3
0.5
4.7
1.8
13.8
13.0
0.011
0.13
0.065
<0.05
0.20
B
55
6.5
0.5
1.4
0.5
5.0
1.7
18,8
12.0
0.017
0.067
<0.05
0.10
C
59
6.7
0.5
1.4
0,5
4.7
0,5
21 .4
13.0
0.016
0.058
<0.05
0.12
D
47
6.7
0.5
1.2
0.5
4.8
2.2
14.0
13.7
0.015
0.088
<0.05
0.20
WELL POINT
E F G
45
6.8
0.5
1.2
0.7
5.0
2,0
14.6
15.0
0.013
0.23
<0.05
0.23
60
6.8
0.5
2.1
0.6
7.5
1.4
21.3
13,4
0.015
0.17
<0.05
0.23
48.5
6.6
0.5
1.2
0.5
4.6
3,4
11.7
15.0
0.013
0.11
0.059
<0.05
0.09
H
48.5
6.7
0.5
1.2
0.6
4.9
2.3
14.1
12.7
0,017
0,16
<0.05
<0.05
0.12
I
53
6.8
1.1
1.6
0.5
6.2
2.3
18.1
16.4
0.021
0.18
0.054
<0.05
0.20
J
40
6.6
1.4
0.9
0.5
4.6
3.2
10.3
14.7
0.013
0.36
<0.05
0.09
K
54
6.8
0.5
1.2
0.6
6.1
2.6
18.0
11.0
0.009
0.077
<0.05
0.08
L
68
6.8
1.1
1.2
0.7
8.5
2.9
27.6
8.3
0.014
0.049
<0.05
0.10
M
56
6.9
1.1
1.4
0.6
6.8
2.5
20.6
12.2
0.019
0.13
0.05
<0.05
0.23
           All values rag/1 unless otherwise stated.
           Dash (—) indicates analysis not made.

-------
specific conductance were noted.  It appears that the septic
tank effluent was causing dissolution of calcium carbonate or
contained elevated calcium and bicarbonate concentrations.  The
soluble orthophosphate concentrations were about the same both
up and down groundwater gradient from the tile field as were con-
centrations of ammonium and nitrate.  Neither total P nor organic
N concentrations showed evidence of contributions from septic
tank effluent.  The concentrations immediately down groundwater
gradient from the tile field were slightly lower than those up-
gradient.
     The observation wells were sampled February 16, 1972, two
weeks after the first sampling.  The data are presented in Table 6.
In general, the pH values were somewhat lower and the soluble
ortho P values were consistently three to five times lower
than those values found during the previous sampling.  The
specific conductance, sodium and alkalinity values showed
that septic tank effluent had migrated as far as well F.  The
calcium concentration was greater in the deeper wells than
in many of the more shallow ones  and roughly corresponded to
the alkalinity values which were generally greatest in the
deeper wells.  None of the available forms of aquatic plant
nutrients  (soluble ortho P, nitrate, ammonium), total P or
organic N  showed an increase in concentration down groundwater
gradient from the septic tank tile field.  Organic N values were
all slightly lower down groundwater gradient from the tile field
than upgradient.
     Table 7 presents data from the well sampling on April 17,
1972, two months after the previous sampling.  The specific con-
ductance values appeared to be somewhat greater down groundwater
gradient from the tile field than the value upgradient.  The
greatest specific conductance values were found in the deeper
wells and  indicated the possibility of effluent movement in the
groundwater.  The pH values were generally one unit above what
they had been at the last sampling.  The calcium concentrations
appeared to be highest in the wells directly down groundwater
                               40

-------
                                                TABLE  6
                  VOYAGER VILLAGE SEPTIC TANK MONITORING STUDY OBSERVATION WELL DATA
                                           (February 16, 1972)
Parameter
Specific
Conductance
ymhos/cm @ 20°C
PH
Cl~
Na+
K+
Ca4*
Mg4*
Alkalinity as
CaC03
so;
Soluble ortho P
Total P
NHJj-N
NO~-N
Organic N-N
A
52
6.2
2.3
1.2
1.1
1.8
2.8
13.5
12
0.005
0.02
0.01
<0.05
0.21
B
55
6.2
2.3
2.1
0.8
6.9
0.7
18.0
10
0.001
0.019
0.06
<0.05
0.09
C
63
6.2
2.3
2.1
0.8
5.9
3.2
22.5
10
0.001
0.019
0.05
<0.05
0.16
D
50
6.0
1.8
1.8
0.2
1.5
2.8
15.0
10
0.005
0.031
0.08
<0.05
0.10
E
15
6.0
1.8
1.1
0.6
1.5
2.1
13.5
9
0.001
0.016
<0.05
0.12
WELL POINT
F G H
73
6.2
1.2
2.2
1.1
10. 1
1.1
21.0
9
0.006
0.061
0.08
<0.05
0.20
58
6.1
0.6
1.8
0.8
5.1
1.1
15.0
18
0.001
0.062
0.05
<0.05
0.16
10
6.3
1.8
1.5
0.8
3.7
2.2
13.5
7
0.001
0.021
0.01
<0.05
0.18
I
56
6.0
1.8
2.3
0.2
5.2
3.6
13.5
10
0.006
0.079
0.08
<0.05
0.09
J
39
6.1
1.2
2.1
0.1
3.1
2.1
10.5
9
0.001
0.025
0.06
<0.05
0.12
K
56
6.1
2.3
1.9
0.8
5.8
3.2
28.5
9
0.001
0.016
0.01
<0.05
0.16
L
73
6.6
1.8
2.0
0.8
9.2
2.8
31.5
8
0.008
0.012
0.06
<0.05
0.16
M
55
6.3
1.8
2.1
0.9
6.0
2.3
21.0
8
0.007
0.011
0.01
<0.05
0.18
All values rag/1 unless otherwise stated.
Dash (—) indicates no analysis made.

-------
                                                 TABLE  7
                    VOYAGER  VILLAGE  SEPTIC TANK MONITORING STUDY OBSERVATION WELL DATA
                                              (April 17, 1972)
Parameter
Specific
Conductance
Vimhos/cm @ 20°C
PH
Cl~
Na+
Kf
Ca"
Mg+ +
Alkalinity
as CaCO-
S0=
Soluble ortho P
Total P
NH*-N
NO--N
A
52
7.4
1.9
2.1
0.5
5.6
2.2
15
11.1
0.008
0.09
0.23
0.12
B
69
7.6
1.9
2.0
0.4
6.6
1.7
51
10.9
0.006
0.08
0.16
0.1
C
69
7.5
1.9
2.0
0.4
7.7
2.2
27
8.3
0.006
0,08
0.12
0.07
D
60
7.4
1.9
1,8
0.4
6.5
2.7
16
11.1
0.009
0.09
0.16
0.11
E
50
7.4
1.9
1.5
0.4
5.2
3.0
18
9.3
0.003
0.05
0.14
0.10
WELL POINT
F G H
74
8.2
1.9
2.4
0.4
6.5
3.5
21
9.1
0.009
0.17
0.13
0.11
50
7.4
1.9
1,8
0.4
5.5
2.8
12
10.9
0.006
0.08
0.36
0.09
40
7.5
1.9
1,5
0.4
4.0
2.8
16
5.3
0.003
0.04
0.18
0.10
I
69
7.6
1.9
2.0
0.4
8.1
3.0
26
8.6
0.008
0.06
0.24
0.09
J
42
7.5
1.9
1,2
0.4
3.9
2.4
12
9.5
0.006
0.12
0.22
0.10
K
80
7.5
1.9
2,2
0.5
9.5
0.7
21
7.7
0.004
0.05
0.34
0.17
L
76
7.7
1.9
2.0
0.4
8.3
4.9
34
8.8
0.005
0.12
0.13
0.10
M
58
7.6
1.9
1.8
0.4
6.4
3.2
21
6.9
0.003
0.02
0.17
0.07
All values mg/1 unless otherwise stated.

-------
 gradient from the tile field and also  in the  deeper  wells  (K and
 L).   None of the aquatic  plant  nutrients appeared  to be  trans-
 ported from the  septic tank effluent through  the groundwater at
 this  sampling.
      The data from samples  collected on  August  29, 1972  (Table 8),
 indicate that septic  tank effluent was moving in the direction
 of estimated groundwater  flow.   The specific  conductance,  chlo-
 ride,  calcium, alkalinity and nitrate levels  all appeared  to be
 greater at  well  points C  and F,  directly down groundwater  gradient
 from  the septic  tank  tile field,  than those at  outlying  or up-
 gradient wells.   Potassium  concentrations varied between 2 and
 5.4 mg/1 without an apparent pattern.  The soluble orthophosphate,
 total  phosphorus and  ammonium concentrations  did not reflect ef-
 fluent contamination,  however.   Those values  at wells down ground-
 water  gradient from the tile field were  generally the same or less
 than values  upgradient.
     Table  9  presents  the data from groundwater samples  collected
 on October  29, 1972.   Since  the  fall of  1972  had been a  particu-
 larly  wet period,  the  concentrations of  some  of the  parameters
 may be markedly  different from those which would normally  be en-
 countered in  shallow groundwater.  The specific conductance  and
 alkalinity both  showed evidence of effluent contamination  of the
 first  tier of wells, the  three deeper wells,  and as  far  directly
 down groundwater  gradient as well points I and M.   The soluble
 orthophosphate concentrations were greater on this date than on
 most of  the previous dates.   This could be related to the high
 rainfall  received that fall.  The down groundwater gradient con-
 centrations were, however, about the same or less  than the con-
 centration above the tile field.  Total phosphorus, ammonium, and
nitrate  from septic tank effluent did not appear to be contaminat-
 ing the  groundwater.  The groundwater turbidity was high in sam-
ples from wells A and F, possibly indicating suspension of sedi-
ment in the well during sampling.
     On January 25, 1973,  wells  A-M were sampled.   Selected sam-
ples were analyzed for only  selected constituents  as  presented
                               43

-------
                                                  TABLE  8
                   VOYAGER VILLAGE  SEPTIC  TANK MONITORING  STUDY OBSERVATION WELL DATA
                                             (August  29,  1972)
Parameter
Specific
Conductance
Umhos/cm @ 20°C
pH
Cl~
+
Na
++
Ca
++
Mg
Alkalinity
as CaCO,
1
Soluble ortho P
Total P
4
NH^-H
NOr -H
O
A


52
6.5
2.3

2.1

5.7

2.5

11.1
6.8
0.060
0.088

0.20
<0.05
B


10
5.7
1.6

2.1

15.0

3.5

21.2
11. 0
0.006
0.021

0.23
0.05
C


68
6
1

2

8

3

21
11
0
0

0
0




.8
.1

.2

.0

.0

.8
.2
.001
.013

.20
.13
D


56
6.9
1.5

2.0

5.7

1.1

17.1
8.5
0,003
0.016

0.17
<0.05
E


18
7.5
1.5

1.6

3.5

0.00

15.1'
10.5
0.005
0.020

0.26
0.06
WELL POINT
F G


61
7.0
2.7

2.3

8.5

1.1

23.2
11.5
0.005
0.022

0.31
0.09


51
6.6
2.8

1.9

5.3

1.1

11.0
11.0
0.003
0.021

0.20
0.06
H


11
6.7
1.8

1.6

1.0

0.8

15.0
5.8
0.001
0.022

0.11
0.06
I


57
7.5
3.3

2.2

6.3

0.1

17,8
11.7
0,008
0.056

0.20
0.17
J


12
7.0
1.8

2.0

8.2

1.8

30.0
7.8
0.002
0.011

0.30
0.06
K


60
7.0
2.1

1.9

8.2

1.9

22.8
7.5
0.002
0.011

0.16
<0.05
L


10
6.9
1.8

1.5

3.2

0.2

10.1
11.7
0.001
0.030

0.28
0.10
H


88
7.0
1.3

2.1

6.1

0.6

20.0
10.0
0.002
0.011

0.030
<0.05
All values mg/1 unless otherwise stated.

-------
                                                TABLE  9
                   VOYAGER  VILLAGE  SEPTIC TANK MONITORING STUDY OBSERVATION WELL DATA
                                           (October  29,  1972)
Parameter
Specific
Conductance
pmhos/cm @ 20°C
PH
Turbidity (NTU)
Cl~
Na +
K +
C-3+4
Mg+ +
Alkalinity
as CaCO~
so=
Soluble ortho P
Total P
NH^-N
NO--N
A

46
5.8
11.4
16.7
1.7
3.0
9.6
1.9
11.6
6.8
0.045
0.07
0.30
0.23
B

62
6.4
5.7
12.8
20.0
<0.5
7.4
2.4
22.0
4.8
C

130
6.5
2.7
20.8
2.6
<0.5
13.4
6.1
31.6
5.5
0.006 0.005
0.04
<0.05
<0.04
0.04
<0.05
<0.04
D

59
6.7
5.4
15.8
1.5
<0.5
5.6
2.4
15.4
5.4
0.041
0.08
<0.05
<0.04
WELL POINT
E F G

44
6.0
3.7
11.9
1.0
<0.5
5.4
1.3
13.5
5.0
0.020
0.04
<0.05
0.48

63
6.3
13.4
11.9
.1.9
<0.5
6.7
1.3
21.2
4.4
0.012
0.09
<0.05
0.17

53
6.7
1.9
12,1
1.2
<0.5
6.1
. 1.8
14.3
4.6
0.048
0.05
<0.05
<0.04
H

39
6.8
4.0
25.0
1.1
<0.5
4.0
1.3
21.2
2.6
0.038
0.05
<0.05
<0,04
I

56
6.8
3.7
14.1
2.0
<0.5
5.8
2.0
23.2
3.0
0.063
0.06
<0.05
<0.04
J

35
6.9
4.3
12.6
0.5
<0.5
3.8
1.1
13.5
3.4
0.036
0.06
<0.05
<0.04
K

66
6.9
4.3
17,3
1.6
<0.5
8.0
2,7
33.6
3.4
0.040
0.08
<0.05
L

70
7.0
2.0
14.9
1.7
<0.5
9.1
3.1
31.3
3.0
0.045
0.10
<0.05
<0.04
M

56
7.1
1.6
18.3
1.7
<0.5
11.2
2.2
21.6
3.0
0.060
0.06
<0.05
<0.04
All values mg/1 unless otherwise stated.

-------
in Table 10.  The specific conductance values indicated the pre-
sence of septic tank effluent in the first tier of wells and at
least as far down groundwater gradient as wells F and L.  Higher
chloride and nitrate concentrations were also found at well C,
but not beyond that point.  There was no detectable movement of
soluble orthophosphate or ammonium from the effluent into the
groundwater at these wells.
     The values of the parameters measured in the groundwater
samples collected on July 26, 1973, are presented in Table 11.
It appeared that most of the transport of effluent occurred down
the central groundwater flow line.  Increased levels of chloride
and nitrate were found at well C; increased specific conductance
was found in the first tier of wells and as far down groundwater
gradient as well I.  No transport of phosphorus was evidenced by
this sampling.  As illustrated by the specific conductance, chlo-
ride and nitrate values, there appeared to be effluent movement
to the right of the central, down groundwater gradient line es-
tablished.  Water from well D showed higher concentrations of
these constituents than did water from well B on the opposite side
of the center line of groundwater flow as estimated by Huff and
Stephenson  (1971).  The specific conductance value was even
slightly above background levels at well G, beyond well D.  If
the direction of flow had changed from that originally estimated,
then additional transport may be occurring which would not have
been found at the wells monitored.  Therefore, it was decided at
this point in the monitoring program to drill two additional wells,
N and 0, about 15  m northwest (perpendicular to estimated ground-
water flow direction) of wells G and D, respectively.
     Table 12 presents data from the analyses of selected ground-
water samples collected on October 10, 1974.  The specific con-
ductance, chloride, calcium, magnesium, nitrate and total kjeldahl
nitrogen values all indicated that the direction of the effluent
movement appeared to be toward well D as well as down the center
(estimated) groundwater flow line.  This pattern had been sug-
gested by the data from the previous sampling 14 months earlier.

                                46

-------
                                         TABLE 10
           VOYAGER VILLAGE SEPTIC TANK MONITORING STUDY OBSERVATION WELL DATA
                                   (January 25,  1973)
Well
Point
A
B
C
D
F
K
L
Specific
Conductance
ymhos/cm
at 20°C
53
74
96
69
75
75
74
pH
6.3
6.5
6.3
6.6
-
6.5
—
Ammonia
mg/1 N
< 0.1
< 0.1
< 0.1
< 0.1
-
< 0.1
—
Chloride
mg/1
0.7
< 1.0
3.0
0.8
0.9
0.5
0.7
Sodium
mg/1
1.4
1.6
1.8
1.4
2.1
1.4
1.7
Soluble ortho
phosphate
mg/1 P
< 0.003
< 0.003
< 0.003
< 0.003
0.003
< 0.003
< 0.010
Nitrate
mg/1 N
< 0.01
< 0.01
0.5
0.01
_
0.01
-
Dash (-) indicates no analysis made.
Samples were analyzed by WARF Institute, Inc., Madison, Wisconsin

-------
CO
                                         TABLE 11
            VOYAGER VILLAGE SEPTIC TANK MONITORING STUDY OBSERVATION WELL DATA
                                     (July 26, 1973)
Well
Point
A
B
C
D
E
F
G
H
I
J
K
L
M
Specific
Conductance
ymhos/cm
at 20°C
48
71
94
89
53
84
64
45
68
42
65
72
54
Chloride
pH mg/1
6.0
6.1
6.7
6.8
6.2
6. 3
6.0
6.2
6.3
6.2
6.6
6.7
6.5
0.7
0.5
3.5
2,3
0.6
1.3
0.7
0.5
0.7
0.5
0,6
0.5
0.6
Sodium
mg/1
1.3
1.8
1.9
1.5
1.0
1.9
1.2
1.0
1.6
0.6
1,4
1.4
1.4
Soluble ortho
phosphate Nitrate
mg/1 P mg/1 N
< 0.01
< 0.01
< 0.01
< 0.01
< 0.01
< 0.01
< 0.01
< 0.01
< 0.01
< 0.01
< 0,01
< 0.01
< 0.01
< 0.02
< 0.02
0.81
0.11
< 0.02
0.11
< 0.02
< 0.02
< 0.02
< 0.02
< 0.02
< 0.02
< 0.02
            Samples were analyzed  by  WARF Institute,  Inc.,  Madison,  Wisconsin

-------
-p
CO
                                                          TABLE  12
                            VOYAGER VILLAGE  SEPTIC TANK MONITORING STUDY OBSERVATION WELL  DATA
                                                     (October 10,  1974)
Parameter
Specific
Conductance
umhos/cm @ 20°C
pH
Cl~
Na*
f
K
Ca"
Mg"
Alkalinity
as CaC03
so=
Soluble ortho P
Total P
NO--N
Total Kjeldahl
Nitrogen
A


53
6.4
0.99
3.34

<10 <
5.10
1.58

15.4
10
0.004
0.008
0.22

0.03
B


73
6.5
1.14
3.64

ao
7.11
2.11

22,0
14
0.005
0.010
0.23

0.07
C


D


88 245
6.6
2.48
3.87

clO
9.32
2.86

30.8
10
0.005
0.012
<0.20

0,50
6.4
25.3
4.16

= 10
21.5
8.33

22,8
15
0.004
0.006
0.72

11.6
E


50
6.8
0.89
4.46

:10 <
<5.0
1,5

17,6
12
0.002
0.007
<0.20

0.07
WELL POINT
F G II


82
6,7
2.48
4.24

:10 <
7.61
2,23

26.4
10
0.003
0.010
<0.20

0.06


59
6.8
1.24
3.27

aO
5.56
1.67

15.4
12
0.003
0.008
<0.20

0.01


42
6.7
0.84
3.12

ao
<5.0
1.29

15.4
4
a. 006
0.027
0.20

0.01
I


70
6.8
1.74
3.19

aO
7.02
2.23

22.0
9
0.004
0.011
0.20

0.03
J


44
6.8
0.99
2.16

ao
<5.0
1.11

13.2
10
0.005
0.016
0.20

0.01
K


58
6.8
0.99
2.82

ao <
5.6
1.79

22,0
8
0.004
0.008
<0.20

0.01
N


52
6.8
0.99
2.71

:10 <
5.27
1.67

15.4
14
0.014
0.034
0.47

0.04
0


53
6.6
0.74
3.34

ao
5.23
1.91

17,6
20
0.019
0.032
0.41

0.03
          All values mg/1 unless othewise stated.
          Samples were analyzed by WARF Institute, Inc., Madison, Wisconsin

-------
The increased concentrations found at well D had not yet appeared
at wells beyond that point.   However, specific conductance,  chlo-
ride, calcium, and alkalinity values were above background levels
all the way down the central groundwater flow line to well I.
The total P and more significantly, the soluble ortho P concen-
trations showed that there had been no phosphate transport from
the septic tank tile field to the groundwater.  The higher con-
centrations of both total and soluble ortho P found at the wells
N and 0 were possibly due to sample contamination resulting from
the newness of these well points.  It is unlikely that they were
due to septic tank effluent contamination since concentrations at
wells D and G were low.
     The last set of samples were collected at the septic tank
monitoring site on January 15, 1976, fifteen months after the
previous samples were collected.   The values of selected para-
meters measured are presented in Table 13.  The highest specific
conductance value was found at well D; the value was also high
at well G, beyond well D.  The highest chloride and sodium con-
centrations were also found at well D.  There was evidence of
chloride contamination beyond that point, at both wells G and  N.
Elevated specific conductance and chloride values were found
along the central groundwater flow direction to well I.  The
deeper wells along that path (K,  L, and M), however, did not
show increased concentrations of chloride.  The pH values of
wells B and E were considerably greater than the rest of the
wells sampled.  Neither total phosphorus nor soluble orthophos-
phate concentrations showed evidence of phosphate transport in
the groundwater downgradient from this septic tank wastewater
disposal system.
                                50

-------
                                                TABLE  13
                   VOYAGER VILLAGE SEPTIC  TANK MONITORING  STUDY OBSERVATION WELL DATA
                                           (January  15,  1976)
en
M





Parameter
Specific
Conductance
umhos/cm @ 22°C
PH
Cl~
Na*
Soluble ortho P
Total P
A
65
7.7
0.8
2.0
0.005
0.32
B
35.5
9.2
0.2
0.8
0.008
0.26
C
73.5
7.8
1.6
2.2
0.008
0.31
D
195
7.8
33.0
3.4
0.008
0.25
E
39.5
9.3
0.3
0.9
0.006
0.18
F
82.5
7.8
2.8
2.2
0.01
0.28
G
81
7
6
2
0
0
WELL.

.6
.2
.0
.008
.14
POINT
H
41.2
7.1
0.6
1.4
0.008
0.30
I
79.8
7.7
3.0
2.1
0.009
0.30
J
45.5
7.5
0.5
1.1
0.006
0.36
K
6U. 5
7.7
0.6
1.7
0.01
0.28
L
85
7
0
1
0
0


,9
.6
.8
.011
.20
M
66
7.7
0.7
1.5
0.01
0.32
N
58
7.5
2.1
1U
0.009
0.38
0
' 9
7.5
0.8
l.M
0.009
0.32
All values mg/1 unless otherwise stated.

-------
                            SECTION  6
                          DISCUSSION

     Examination of data for the four-year monitoring study shows
that septic tank effluent did migrate from the tile field into the
groundwaters of the region.   This conclusion was based on the
data for conservative or essentially conservative chemical tracers
such as specific conductance and chloride, and other parameters
which may not be conservative.  Data collected during this study
showed occasionally elevated nitrate and ammonium concentrations
in certain wells, but it did appear that there was appreciable
nitrogen removed in this aquifer system.  No evidence for phos-
phate transport from septic tank effluent was found in any of
the monitoring wells, even though this was a sand aquifer with
a relatively high groundwater velocity.  Except for the first
sampling, there appeared to be no seasonal effects on chemical
constituents at the monitoring wells which could be traced to
the nine month per year occupancy of the household.
     The potential for adverse effects on surface water quality
resulting from groundwater transport of aquatic plant nutrients
                       !
from septic tank wastewater disposal system effluent is control-
led by a number of factors.   When examining a functioning septic
tank wastewater disposal system to determine whether there is a
significant contribution to surface water of the phosphorus dis-
charged to the system from a household, it is necessary first to
define the groundwater hydrology of the region.  Often, as was
found in the Voyager Village development area, there is no rela-
tionship between surface topography and direction of groundwater
flow.  Far too often, it is assumed that the hydrology of ground-
waters surrounding a lake is such that the direction of the flow
is toward the lake.  For many lakes, the groundwater flow is in
                               52

-------
on one side and out on the other.  Those septic tank wastewater
disposal systems that are located on the down groundwater gradient
side of the lake do not contribute phosphorus or any materials to
that particular surface water.
     The chemical characteristics both of the unsaturated zone be-
tween the tile field and the water table and of the aquifer ma-
terials determine to a large"extent whether or not aquatic plant
nutrients will be transported in the groundwater.  Closely as-
sociated with this factor is the rate of groundwater flow and the
distance between a septic tank system and a water body of concern.
Soluble phosphate and ammonium can be sorbed by clay minerals.
In addition, phosphate can be sorbed by aluminum and iron oxides,
and other minerals in the soil.  Phosphate sorption is usually
a rapid process, 80 to 90 percent complete in two to five days
(Tofflemire et al., 1973).  The typically slow movement of ground-
water allows for precipitation of soluble phosphate with calcium.
The greater the distance the septic tank disposal system is from
a water body, the greater the potential for phosphorus removal
by the aquifer materials.
     It is the chemical composition of the soils rather than grain
size characteristics which plays the dominant role in phosphorus
removal.   Soils in the Voyager Village development area were
predominantly fine to medium sands.  Even though septic tank ef-
fluent was readily measurable in observation wells 60 m downgradient
from the septic tank tile field monitored, the sandy aquifer ma-
terial exhibited complete phosphate removal during the course of
the four-year monitoring study.
     It is possible that over a period of time, aquifer material
sorption sites will become saturated with phosphorus.   However,
there is  essentially infinite capacity for phosphorus  removal due
to precipitation reactions.   Indeed, some investigators have in-
dicated that the capacity for phosphorus removal may be independent
of prior exposure to phosphorus.
     Another condition affecting potential significance of ground-
water transport of aquatic plant nutrients is that there must be

                                 53

-------
actual recharging of the water body of interest by the ground-
water.  Especially in glaciated regions, there can exist beneath
lakes  an impervious clay layer which acts to separate the lake
from possible groundwater input.  The groundwater then flows be-
neath or around the lake and no contributions of nutrients or
other contaminants to the lake can be made by the groundwater.
Some of these so-called perched lakes were found in the Voyager
Village development area.
     An important factor that should be considered in making a
proper assessment of the significance of septic tank wastewater
disposal systems as a source of phosphorus for surface waters is
the proximity of the septic tank system to the water body of con-
cern with respect to excessive fertilization.  For many water
bodies, any phosphorus transported from septic tank wastewater
disposal system effluent would be contributed to a lake or a stream
which is tributary to that water body.  As discussed below, a sub-
stantial part of this phosphorus never reaches the downstream
water body in a form that is available to support algal growth.
For almost any lake, there would be on the order of 60. to 90 per-
cent retention of the annual phosphorus load within the lake sedi-
ments.  This means that for the lake which is ringed by cottages
with septic tanks where either the septic tanks have failed or
where the subsoil system does not take up the phosphate, while the
phosphorus would contribute to the eutrophication problems within
the receiving water body, only a small fraction of the phosphorus
would actually be transported to downstream water bodies.
     An example of this type of situation is the US-Canadian
Great Lakes.  It would be expected that very little direct
phosphate transport due to the utilization of septic tank waste-
water disposal systems  would be occurring from residences located
on the shores of the Great Lakes.  Rather, these inputs are general-
ly made to a tributary lake or stream.  Little of the P from septic
tanks located in the Great Lakes Basin would reach the Great Lakes
in an available form to thereby contribute to the excessive fer-
tilization of these water bodies.  The basis for this conclusion

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is that a large part of the phosphorus present in streams and
rivers, especially during periods of high flow, frequently becomes
associated with particulate matter where the phosphorus is attached
to or becomes incorporated into clay.  Further, as available P is
utilized in various biological processes, it is becoming less avail-
able for stimulation of algal growth since each time it is cycled
through a biotic system,some part of the phosphorus becomes re-
fractory.  This thereby prevents it from stimulating algal growth.
Studies supported by the US EPA conducted by Lee and his graduate
students several years ago have shown that much of the particulate
phosphorus in several rivers is unavailable for algal growth (Cowen
and Lee, 1976).  In general, it is likely that available nutrients
discharged to rivers which are considerable distances from the lake
of interest will have much less influence on stimulating extensive
fertilization problems than would the same nutrients discharged
directly to the water body.
     If aquatic plant nutrients do enter a lake from the ground-
water, conditions existing in the lake could reduce their impact
on the water quality.  For example, if groundwater recharge were
beneath an existing thermocline, such as may be present during
the summer growing season, added nutrients would remain trapped
in the hypolimnion.  The interactions between the sediments in
the lake and the nutrients entering the lake via groundwater flow
would tend to convert both nitrogen and phosphorus to forms un-
available for stimulation of algal growth.
     Another factor contributing to the overall significance to
surface water quality of aquatic plant nutrient transport from
septic tank effluent is the growth limiting element in the down-
gradient water body.  If nitrogen is the limiting nutrient in the
water body of concern during the times of year of concern, as may
be the case in some of the Voyager Village development area lakes,
it is possible that additions of phosphorus to that water body
from the groundwater would have no effect on the surface water
quality.
                                55

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     In assessing the overall impact on surface water quality of
available nutrient contributions from septic tank effluent, con-
sideration must be given to sources and magnitudes of other nu-
trient inputs to the water body such as urban and agricultural run-
off, point source inputs, atmospheric inputs, in addition to other
sources of nutrients in groundwater such as fertilizers or sani-
tary landfill leachate.  It is possible that the contribution of
aquatic plant nutrients of septic tank effluent origin to a water
body would be insignificant when compared to other nutrient sources
which may be readily controllable.
     From this  and previous studies, it appears that, in general,
phosphate will not be transported from the septic tank wastewater
disposal systems to surface waters and thereby contribute to exces-
sive fertilization problems.  However, it is conceivable that
there may be a very limited number of water bodies where septic
tank disposal systems are located immediately adjacent to a lake
and contribute sufficient phosphorus to the lake to stimulate ex-
cessive algal and/or macrophyte growth.  Under these conditions,
consideration should be given to either construction of a sewerage
system to collect all wastewaters and provide adequate treatment
for phosphate removal or modification  of the septic tank waste-
water disposal system to improve its phosphate retention capacity.
Based on previous, unpublished work by the authors, phosphorus
removal can be accomplished by the inclusion of limestone or
aluminum oxide in the septic tank wastewater disposal system tile
field or in a dike which is constructed below the soil surface
through which the wastewaters from the septic tank tile field
must pass en route to the nearby water course.   Sikora ejb al.
(1976)  demonstrated the effectiveness of an individual home
phosphorus removal system, using a vertical Plainfield sand col-
umn followed by a series of columns filled with calcite or dolo-
mite.  The most effective of the systems tested was one in which
0.32 cm diameter calcite particles were used.  It showed 99 per-
cent P removal during the first month but it decreased to 12
                                56

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percent in the sixth month of operation.  Additional field evalua-
tion of this approach should be made under a variety of conditions
in order to determine the optimum design parameters to maximize
phosphate retention.  This or similar approaches using aluminum
oxide is likely to be a cost-effective way to remove essentially
all of the phosphorus present in septic tank wastewater disposal
system effluent where there is potential for significant surface
water contamination.
                               57

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                         REFERENCES
American Public Health Association, American Water Works
     Association, Water Pollution Control Federation, Standard
     Methods for the Examination of Water and^Wastewater, 12th
     Edition, American Public Health Association, New York.
     (1965).

American Public Health Association, American Water Works
     Association, Water Pollution Control Federation, Standard
     Methods for the Examination of Water and Wastewater, 13th
     Edition, American Public Health Association, New York.
     (1971).

American Public Health Association, American Water Works
     Association, Water Pollution Control Federation, Standard
     Methods for the Examination of Water and Wastewater, mth
     Edition, American Public Health Association, Washington,
     D.C. (1976).

Beek, J., F.A.M. deHaan, and W.H. van Reimsdijk, "Phosphates
     in Soils Treated with Sewage Water:  I. General Information
     on Sewage Farm, Soil and Treatment Results,"  J. Environ.
     Qual. 6,:4-7 (1977a).

Beek, J., F.A.M deHaan,. and W.H. van  Reimsdijk, "Phosphates
     in Soils Treated with Sewage Water:  II Fractionation of
     Accumulated Phosphates," J. Environ. Qual, §:7-12  (1977b).

Blackman, R.R., L.M. Slather, and C.W. Threinen,"Surface Water
     Resources of Burnett County," Wisconsin Conservation
     Department, Madison (1966).

Boyle, W.C., and L.B. Polkowski, "Groundwater Quality Adjacent
     to Septic Tank - Soil Absorption System," Dept. Nat.
     Res., Madison, Wisconsin (1970).

Brandes, M., N.A. Chowdry and W.W. Cheng, "Experimental Study
     on Removal of Pollutants from Domestic Sewage by Under-
     drained Soil Filters," National Home Sewage Disposal.
     Symposium, Am. Soc. Agric. Engr., Chicago, Illinois
     (197U).
                               58

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 Carlson, K.G, Persona,! Communication to G. Fred Lee, (July 5,
      1973),                                                  ?

 Childs, K.E., "Migration of Phosphorus Wastes in Ground Waters,"
      Geological Survey Division, Mich. Dept. of Natural Resources
      (May, 1974).

 Corey,  R.B.,  A.D. Hasler, G.F,  Lee,  F.H.  Schraufnagel and T.L.
      Wirth, "Excessive Water Fertilization,"  Report to Water Sub-
      committee,  Nat.  Res. Comm,  of State  Agencies,  Madison, Wis-
      consin (1967).

 Cowen,  W.F. and G.F.  Lee, "Algal Nutrient Availability and Limita-
      tion in  Lake Ontario During IFYGL, Part I,  "Report to US EPA
      Large Lakes Research Station,  Grosse lie,  Mich.  (1976).

 Dillon, P.J.  and F.H,  Rigler,  "A Simple Model for Predicting  the
      Capacity of a Lake for Development Based on Lake Trophic
      States," J.  Fish.  Res.  Board,  Canada _32_: 1519-1531  (1975).

 Dudley, J.G.  and D.A.  Stephenson,  "Nutrient  Enrichment  of Ground-
      water from  Septic Tank Disposal  Systems," An Inland Lake Re-
      newal and Shoreland Management Demonstration Project Report,
      Upper Great Lakes Regional  Comm.  (1973).

 Ellis,  E.G.,  "Gull Lake Investigations:   Nutrient Input Studies,"
      Dept.  Crop  and Soil Sciences, Mich,  State Univ.  (September,
      1971).

 Ellis,  E.G. and  A.E. Erickson, "Movement  and  Transformation of
      Various  Phosphorus  Compounds in  Soils,"  Soil Sci.  Dept.,
      Mich.  State  Univ.  and Mich, Water Resources Comm.  (1969a).

 Ellis,  E.G. and A.E. Erickson, "Gull  Lake  Investigation,  Part II,"
      Nutrient  Input Studies, Mich. State Univ. (1969b).

 Enfield, C.G., "Phosphate Transport through Soil," Prepared for
      presentation  at the National Conference on Disposal  of Resi-
      dues  on Land, St.  Louis, Mo. (1976).

 Enfield, C.G. and  B.E.  Bledsoe, "Kinetic  Model for Orthophosphate
      Reactions in Mineral Soils," National Environmental  Research
      Center, US EPA, Corvallis, Oregon, EPA-660/2-75-022  (1975).

Grim, R.E., Clay Minerology, McGraw-Hill,  New York,  384 pp. (1953).

Hansen,  G.L., "Groundwater Quality Adjacent to a Septic Tank-
      Soil Absorption System," Unpublished  M.S. thesis, Univ. of
     Wise., Madison, Wisconsin (1968).
                               59

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Henderson, J. , "Gull Lake Investigations, Part I, Demographic
     Survey," Mich. State Univ. (1969).

Huff, D.D, and D.A, Stephenson, "Hydrologic and Hydrogeologic
     Investigations of the Voyager Village Project Site, Burnett
     County, Wisconsin," Report to N.E. Isaacson S Associates
     (November, 1971).

Keeley, J.,   Chief,   US EPA Groundwater Research Program.
     Personal Communication to G. Fred Lee (1976).

Lee, D.R., "The Role of Groundwater in Eutrophication of a
     Lake  in Glacial Outwash Terrain," Int. J. Speleol . ,  £:
     117-126  (1976a).

Lee, G.F., "Review of the Potential Water Quality Benefits from
     a Phosphate Built Detergent Ban in the State of Michigan,"
     Presented at Michigan Dept. of Natural Resources Hearing
     on a  Detergent Phosphate  Ban, Lansing, Michigan (December
     8, 1976b).

New York  State Department of Health.  The Long Island Ground
     Water Pollution Study, New York State Dept. of Env.  Con-
     servation (1972).

Okun, D.A. "Phosphates in Detergents - Ban or Boon?" Environ-
     mental Affairs, 2.: 64-79 (1972).

Reneau, R.B., Jr. and D.E. Pettry, "Phosphorus Distribution
     from Septic Tank Effluent in Coastal Plain  Soil," J.
     Environ. Qual.  5.: 34-39  (1976).

Sikora, L.J., M.G. Bent, R.B.  Corey, and D.R. Keeney,  "Septic
     Nitrogen and Phosphorus Removal Test System," Groundwater
     3Jt:309-314  (Sept-Oct.,  1976).

Smith,  S.O.  and  D.H. Myott,  "Effect of Cesspool  Discharge on
     Groundwater Quality on  Long Island, N.Y.,"  J. Amer.
     Water Works Assoc. ££:456-458  (1975).

Stephenson,  D.A.,  "Hydrogeologic Investigations  of the Voyager
     Village Project  Site, Burnett County, Wisconsin," Report
     to N.E.  Isaacson and Associates  (February,  1971).

Stumm,  W.  and J.J. Morgan, Aquatic Chemistry, Wiley-Interscience,
     New  York (1970).

Thomas,  N.A.  of  US EPA  Large Lakes Research  Station, Grosse  lie,
     Michigan.   Letter  to  K.A. Booman  (November  30,  1976).
                                60

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Tofflemire, T.J,, M, Chen, F.E, Van Alstyne, L,J, Hetling and
     D,B. Aulenbach, "Phosphate Removal by Sands and Soils,"
     Tech. Paper 31, New York State Dept. of Environ. Con-
     servation  (1973).

Viraghavan, T. and R.G. Warnock, "Efficiency of a Septic Tile
     System," J. Water Poll. Cont. Fed. _48: 934-944 (1976a).

Viraghavan, T, and R.G, Warnock, "Groundwater Quality Adjacent
     to a Septic Tank System," J. Amer. Water Works Assoc.
     £8:611-614 (1976b).

Wirth, H.E. and R.C. Hill, Summary Report of a Survey of Pri~
     vate Sewage Disposal Systems Serving Water Front Properties,
     Wisconsin Department of Health and Social Services Division
     of Health, Madison, Wisconsin (1967).
                               61

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                             TECHNICAL REPORT DATA
                       (Please read Instructions on the reverse before completing)
 REPORT NO.
  EPA-600/3-77-129
                                                  3. RECIPIENT'S ACCESSION-NO.
 TITLE AND SUBTITLE
    SEPTIC TANK. DISPOSAL SYSTEMS AS
    PHOSPHORUS SOURCES  FOR SURFACE WATERS
            i. REPORT DATE
              November 1977 issuina
            6. PERFORMING ORGANIZATION CODE"
. AUTHOR(S)
                                                  8. PERFORMING ORGANIZATION REPORT NO.
    Rebecca A. Jones  and G. Fred Lee
. PERFORMING ORGANIZATION NAME AND ADDRESS
  Institute for Environmental Sciences
  The University of Texas  at Dallas
  Post  Office Box 688
  Richardson, Texas   75080    	
            10. PROGRAM ELEMENT NO.
                 1BA609
            11. CONTRACT/GRANT NO.


                         R-80U549
12. SPONSORING AGENCY NAME AND ADDRESS
Robert S. Kerr Environmental Research Lab,
Off ice., of Research, and Development
J.S. Environmental Protection Agency
Ada,. Oklahoma.74820	
- Ada, OK
13. TYPE OF REPORT AND PERIOD COVERED

	Final	
14. SPONSORING AGENCY CODE
                EPA/600/15
IB. SUPPLEMENTARY NOTES
16. ABSTRACT
     A  H-year groundwater monitoring  study was conducted in the  immediate
vicinity  of an active  septic tank wastewater disposal system in  the sandj
stfbstrate in Burnett County of northwestern Wisconsin to determine the
potential for this method of wastewater disposal  to contribute to excess: ve
fertilization of surface waters.  To  monitor the  movement of the effluenl
and the character of the area groundwater, selected parameters were mea-
sured in  water samples collected from an array of wells located  up and
down groundwater gradient from the  septic tank tile field.
     During the course of this study, movement of septic tank effluent it
the groundwater was indicated by measured values  of several of these param-
eters.  However, there was no evidence of the transport of the phosphate
from septic tank effluent through the groundwater even at the monitoring
point closest to the tile field (about 15 m down  groundwater gradient frc m
the tile  field).  The  results of this study confirm the conclusions drawr
from similar studies in other areas reported in the literature,  that pho£
phorus  from septic tank wastewater  disposal system effluent is u jually nc t
readily transported through the groundwater.  Therefore, septic  tank was- e
water disposal systems generally do not contribute significant amounts o:
phosphorus to surface  waters to contribute to their excessive fertilization.
17.
                           KEY WORDS AND DOCUMENT ANALYSIS
a.
               DESCRIPTORS
                                       b.lDENTIFIERS/OPEN ENDED TERMS
    Septic Tanks
    Phosphorus
   Waste  Disposal
   Surface Waters
   Ground Water
  Phosphorus Migration
                          COSATI Field/Group
                 13/B
18. DISTRIBUTION STATEMENT
    Release to Public.
                                        19. SECURITY CLASS (ThisReport)
                                           Unclassified
                        21. NO. OF PAGES

                               72
 20. SECURITY CLASS (Thispage)

     Unclassified
            22. PRICE
EPA Perm 2220-1 (9-73)
62  '
                                           #U.S. GOVERNMENT PRINTING OFFICE: 1S78-757-1W6617 Region No. 5-11

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