EPA-600/2-77-054
April 1977
Environmental  Protection Technology Series
                                                                 OF
              SLUDGE  DISPOSAL  RECYCLING  HISTORY
                                       Municipal Environmental Research Laboratory
                                            Office of Research and Development
                                            U.S. Environmental Protection Agency
                                                     Cincinnati, Ohio 45268

-------
                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 ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.

-------
                                           EPA-600/2-77-054
                                           April  1977
     COMPREHENSIVE SUMMARY OF SLUDGE DISPOSAL
                 RECYCLING HISTORY
                        by

                  John C.  Baxter*
                William J. Martin*
                 Burns R.  Sabey**
                 William E. Hart**
                  David B. Cohen*
                 Carl F. Calkins*

*Metropolitan Denver Sewage Disposal District No. 1
          Commerce City, Colorado  80022

            **Colorado State University
           Fort Collins, Colorado  80521
              Contract No. 68-03-2064
                  Project Officer

                   James A. Ryan
           Wastewater Research Division
    Municipal Environmental Research Laboratory
              Cincinnati, Ohio  45268
    MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
        OFFICE OF RESEARCH AND DEVELOPMENT
       U.S. ENVIRONMENTAL PROTECTION AGENCY
              CINCINNATI, OHIO  45268

-------
                                 DISCLAIMER
     This report has been reviewed by the Municipal Environmental Research
Laboratory, U. S. Environmental Protection Agency, and approved for publica-
tion.  Approval does not signify that the contents necessarily reflect the
views and policies of the U. S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or
recommendation for use.
                                     11

-------
                                 FOREWORD
     The Environmental  Protection Agency was created because of increasing
public and government concern about the dangers of pollution to the health
and welfare of the American people.  Noxious air, foul  water, and spoiled
land are tragic testimony to the deterioration of our natural environment.
The complexity of that environment and the interplay between its components
require a concentrated and integrated attack on the problem.

     Research and development is that necessary first step in problem solu-
tion and it involves defining the problem, measuring its impact, and search-
ing for solutions.  The Municipal Environmental Research Laboratory develops
new and improved technology and systems for the prevention, treatment, and
management of wastewater and solid and hazardous waste pollutant discharges
from municipal and community sources, for the preservation and treatment of
public drinking water supplies, and to minimize the adverse economic, social,
health, and aesthetic effects of pollution.  This publication is one of the
products of that research; a most vital communications link between the
researcher and the user community.

     This history of land utilization of wastewater sludge was conducted for
the Ultimate Disposal Section of the Wastewater Research Division to gain
insight into the ramifications of land application when used by a large
municipality, as well as to document the results of the Metropolitan Denver.
Sewage Disposal District No. 1 in their efforts to utilize this process.
                                          Francis T. Mayo
                                          Director
                                          Municipal Environmental Research
                                          Laboratory
                                     i i i

-------
 Pile* 06  Ondutie.

 Vo you know what the^e.  p-Uei OjJ o/tdate ate,
 Colle.cte.d at ^t/ie cU,ght6ul 6aAA.et6 0(J  tkn nightman,
 And the. fi&tid t>&i QfL game.,  it iA  cattle.,
  it  the. Aatiiifiied towing oft heavy fe^.ne;
At night it   uxvw blood i.n  you/i uex.R6,
  it U  health,   it ti> joy,   it
                         dicta*. Hugo, In Let  MiAeAableA  {1S62
                              iv

-------
                                  ABSTRACT
Processing and ultimate disposal  of wastewater sludge  is  one  of  the most
costly unit processes within any  sewage treatment plant.   Since  1969  the
Metropolitan Denver Sewage Disposal  District No.  1  (Metro)  has been ex-
amining methods of sludge disposal  which are both economical  and environ-
mentally sound.  The original  flash-dryer incinerator  units installed at
Metro proved to be costly and environmentally unacceptable, therefore,
land application became a viable  alternative to flash  drying  or  inciner-
ation.

Since 1971 the only mode of sludge  disposal  used by Metro has been land
application.  A number of different application procedures  have  been  tried
over the intervening years.  The  development of methodology and  problems
associated with each procedure are  discussed in the text.

Continuous applications of sludge to the soil at the Lowry Bombing Range
since 1969 have raised the concentration of nutrients,  metals, salts  and
organic matter.  The effects of these loading rates on the soil,
crops and environment are evaluated.

The effects of various sludge applications to soil  on  germination, emer-
gence, subseqeunt plant growth and  heavy metals uptake are discussed.  Im-
proved wheat yields were experienced with sludge application rates up to
50 metric tons per hectare.  Low  germination and emergence rates were found
when crops were planted immediately after sludge incorporation.   Inhibition
of germination decreased with increasing soil sludge incubation  periods or
when dried sludge was used, suggesting that salts or some volatile component
within the sludge was inhibiting  germination.  Sorghum sudangrass was most
inhibited by sludge additions, and  was affected to some extent by all sludge
treatments.  Corn was intermediate  in tolerance, and wheat was the least  af-
fected by sludge additions.  There  appeared to be no inhibition  of germina-
tion and emergence of wheat and corn after an incubation period  of one month.

Microbial counts showed that sludged plots had an appreciable increase in to-
tal aerobic, total coliform and fecal streptococci  bacteria.   Counts  of fecal
coliform bacteria demonstrated that there were no appreciable differences be-
tween the sludged and control  plots.

Experiments examining the possibility of air drying anaerobically digested
liquid sludge in shallow earthen  drying basins demonstrated that water is
lost through soil percolation in  addition to evaporation, and that about  half
of the nitrogen (N) content of sludge is lost during the drying  process.  A
discussion of future research needs is also included in the text.

-------
                                 CONTENTS

Foreword	  i i i
Abstract	    v
Figures	viii
Tabl es	   i x
     I.  Introducti on	   1
    II.  Initial Experiences in Sludge Handling and Disposal	   3
   III.  Development of Land Application Technology	   5
    IV.  Evaluation of Sludge Disposal at the Lowry Bombing Range	  14
         A) Type of Sludge	  14
         B) Soil Effects of Sludge Disposal at the Lowry Bombing Range...  16
     V.  Research and Development	  23
         A) Land Application of Metro Sewage Sludge at Watkins, Colorado.  24
            1) Materials and Methods	  24
            2) Results and Discussion	  28
            3) Conclusions	  42
         B) The Effect of Metro Sludge on Germination and Plant Growth
            of Three Crops in a Greenhouse Study	  43
            1) Materials and Methods	  43
            2) Results and Discussion	  44
            3) Conclusions	  48
         C) Sludge Air Drying Project	  51
            1) Materials and Methods	  51
            2) Results and Discussion	  51
            3) Conclusions	  56
    VI.  Future Agricultural Research and Development Projects	  57
   VII.  Appendix	  70
  VIII.  Glossary	  84

-------
                                  FIGURES
NO.

 1.
 2.
 3.
 4.
 5.
 6.
 7.
 8.

 9.
10.

11.

12.

13.
14.

15.

16.

17.

18.

19.
Filter cake sludge being tail gated onto soil  surface.
Location map of Lowry Bombing Range sludge recycle  site.
Sludge being transferred to 10 cubic meter manure spreaders.
Transport vehicle dumping into sludge storage hopper.
Modified fertilizer spreader broadcasting sludge.
Mold board plow incorporating sludge.
Lowry Bombing Range sludge recycle site showing areas  used
 for soil monitoring; shaded areas represent  fields to which
 sludge has been applied.
Plot design layout with identification and loadings (dry
 metric tons per hectare) of each plot.
1972 wheat yield on filter cake plots.
pH of soil profile with various rates of sewage sludge addi-
 tions.
Electrical conductivity of soil with various  rates  of  sewage
 sludge application.
Organic matter content of soil with various rates of sewage
 sludge additions.
N03-N of soil with various rates of sewage sludge additions.
Available P content of soil with various rates of sewage
 sludge additions.
Available K content of soil with various rates of sewage
 sludge additions.
DTPA extractable Zn content of soil with various rates of
 sewage sludge additions.
DTPA extractable Fe content of soil with various rates of
 sewage sludge additions.
DTPA extractable Cu content of soil with various rates of
 sewage sludge additions.
DTPA extractable Mn content of soil with various rates of
 sewage sludge additions.
PAGE

  5
  6
  9
 10
 11
 12
 18
 26

 32
 34

 34

 35

 36
 36

 37

 37

 38

 38

 39
                                     viii

-------
                                   TABLES
NO.                                                                        PAGE
1      Comparison of incinerator versus  land application  sludge              10
       disposal  costs
2      A comparison of chemical  composition of ferric  chloride               15
       and lime treated vacuum  filter cake with  polymer  conditioned
       vacuum filter cake (1972-1975 data)
3      Concentrations of DTPA extractable  Zn, Fe, Cu,  Mn  and  pH  from         17
       sludge additions to surface soils  (0-15.24 cm)  at the Lowry
       Bombing Range
4      Comparison of chemical constituents of soil samples taken  at           19
       Lowry in May 1974 and November 1974
5      Concentrations of N03-N,  NHj-N, TKN, P, K  and  conductivity            20
       from sludge additions to surface soils (0-15.24 cm) at the
       Lowry Bombing Range       +
6      Concentrations of NOs-N,  Nfy-N and  TKN from subsurface soils          21
       (61 to 91 cm depth) at the Lowry Bombing  Range
7      Total metal composition of soil and wheat  from the Lowry              22
       Bombing Range
8      Characteristics of the Truckton loamy sand used in the study          24
9      Typical analysis of anaerobically and aerobically  digested            25
       sewage sludge produced by the Metropolitan Denver Sewage
       Disposal  District No. 1
10    Germination and emergence counts  on July 20, 1971  for  three           29
       rows, each 7.65 meters long
11    Wheat stand counts on October 15, 1971 for three rows, each           29
       1.83 meters long
12    Yield and nitrogen content of sorghum sudangrass as affected          30
       by sludge application rate
13    Effect of sewage sludge addition  to Truckton loamy sand on            3]
       winter wheat yields, 1972
14    Total elemental composition of wheat grain as  influenced  by           32
       rate of Metro sewage sludge addition
15    8.1 hectare filter cake demonstration showing  wheat yields in         33
       kilograms dry matter per hectare
16    Bacterial  counts of soil  samples  taken from fields (fallow            49
       and sorghum sudangrass)  treated with sewage sludge
17    Average values for infiltration rates on sludge treated soils         40
18    Significant variables found in modeling water  applications of         42
       1.27, 2.54, 5.08 and 10.16 centimeters
19    Rate of sludge applications to Truckton sandy  loam soil               43
20    Soil incubation periods and corresponding  planting, thinning          44
       and harvest data

                                     ix

-------
M                                                                        PAGE
21 a   The effect of sewage sludge on germination and emergence             45
       of seeds of three crops.  Seeds planted one month after
       the treatments were mixed with soil
21b   Seeds planted three months after the treatments were mixed           46
       with soil
21c   Seeds planted six months after the treatments were mixed             47
       with soil
22    The effect of sewage sludge on early growth (two weeks after         49
       planting) of three crops grown in a greenhouse
23    The effect of sewage sludge on oven dry weight of three crops        50
       grown in a greenhouse for 2 to 3 months
24    Initial depth of liquid sludge                                       52
25    Change in percent total solids content of drying basin with          52
       ti me
26    Net evaporation required (centimeters per year) at various           54
       sludge loading rates
27a   Nitrogen concentration of 3 layers of liquid sludge in drying        55
       basins
27b   Nitrogen concentration as a percent of the total solids con-         55
       centration of the three stratified samples
28    Range in various chemical constituents of liquid sludge con-         56
       tained in drying basins

-------
                                INTRODUCTION


Sludge handling and disposal are the most problematic and costly unit pro-
cesses in wastewater treatment, particularly for large municipal wastewater
treatment facilities.  At the Metropolitan Denver Sewage Disposal District
No. 1 (Metro) the cost of sludge disposal has been continuously increasing.
During 1974, sludge handling and disposal accounted for over one-half of the
total annual operation and maintenance budget.

Ultimate disposal of residues removed by the treatment process must enter
the ecosystem via one or more of three alternate pathways, land, atmosphere
or water.  Since the Metro plant went on-line in 1966, three alternate sludge
disposal  pathways have been utilized, each with particular advantages and dis-
advantages.  The water pathway for sludge disposal  is particularly inappropri-
ate in a semi-arid climate such as eastern Colorado where water resources are
seriously limited and must be protected.   Inadvertent air pollution by incin-
eration or other means is rapidly becoming socially unacceptable.  This is
particularly so in Denver where altitude and topography combine to make air
pollution entrapment during temperature inversions a serious concern.  Having
ruled out the air and water pathways by trial and error, the only remaining
alternative for Metro was the application of sewage sludge residues to land.

One possible method of land application involves sanitary landfill ing or
burial of ash obtained from incineration of sewage sludge.  While incinera-
tion provides a relatively inert residue which  can be disposed of on land,
this method has certain drawbacks.  In addition to air pollution, incinera-
tion destroys a potential resource.   The increasing awareness of the finite
limitations of natural resource development has led to a search for new uses
for what have previously been considered wastes.  Sewage sludge is a major
untapped resource which contains significant concentrations of nitrogen,
phosphorous, micronutrients, and humic materials.  While this fact has been
known for years, the relatively low cost of synthetic commercial fertilizer
and soil  amendment materials inhibited the farming community from exploit-
ing sewage sludge for growing crops.  Recent economic developments, partic-
ularly the diminishing availability of energy and its fertilizer by-products
have created a new climate of greater acceptance for the beneficial recycling
of sewage sludge to land.  However,  this alternative also poses potential
problems  such as heavy metals buildup in soils  and plants, pathogen dissemi-
nation,  and nitrate pollution of ground water.   These problems can be over-
come by judicious loading rates, cropping, and  environmental  monitoring.

The Metro District is not unique in  having to cope with these problems.   The
authors  of this report hope that other agencies charged with handling of sew-
age residues can benefit from Metro's experience in pursuit of a solution
for economically and ecologically recycling sewage sludge.

                                      1

-------
The first four sections of this report summarize Metro's sludge handling
and disposal history from 1966 to the present time.  The fifth and sixth
sections describe the research and development efforts to solve existing
problems as well as to anticipate future problems.  The seventh and final
part attempts to summarize the operational and research experience with
recommendations for future efforts.

-------
             INITIAL EXPERIENCES IN SLUDGE HANDLING AND DISPOSAL


The Metro plant was designed to treat 117 MGD (million  gallons  per day) of
wastewater.  The residues removed in the process were to be dewatered  through
dissolved air flotation and vacuum filtration,  and ultimately disposed of by
flash drying and/or incineration.  The anticipated ratios of raw  primary, an-
aerobically digested primary and undigested waste activated sludge which  com-
prised the vacuum filter feed sludge were expected to yield a filter cake mois-
ture content of no greater than 78%.  The chemicals required for  sludge condi-
tioning prior to vacuum filtration were expected to average 5%  FeCls (ferric
chloride) and 10% lime.  If these design conditions had been realized, the
amount of water requiring evaporation at full plant capacity would have equaled
311.2 metric tons per day.  The design engineers provided three FDI (flash-dry-
er incinerator) units each having a maximum evaporative capacity  of 5.9 metric
tons water per hour.  All three units operating at 100% of the  designed capa-
city would have provided a total evaporative capacity of 425 metric tons  of
water per day.

Early in 1967 it became apparent that the ratio of waste activated sludge to
the total sludge mixture was much greater than originally anticipated  by  the
design engineer.  The higher quantity of more difficult to dewater waste  acti-
vated sludge had an adverse effect on the vacuum filter cake solids concentra-
tion, which averaged 14% to 18% TS (total solids) instead of the expected 22%
to 25%.  This adverse sludge ratio increased the original design estimate for
chemicals required for vacuum filtration by more than 100%.  This sequence of
events led to a serious overload condition of the evaporative capacity of the
FDI units.  Mechanical problems and breakdowns as a result of the overload con-
dition were exacerbated by FeCl3 (ferric chloride) induced corrosion failures
of the stainless steel components of the FDI units.

By the fall of 1968 the sludge handling and disposal problem had reached
crisis proportions.  As a result of mechanical problems, less than half of the
evaporative capacity of the FDI  units was available for sludge disposal.   Acti-
vated sludge accumulation in the biological treatment system caused a rapid
deterioration of final effluent  quality.  In order to avoid scouring of acti-
vated sludge from  the  secondary  clarifiers into  the South Platte River,  lagoons
were constructed for the temporary storage of excess activated sludge.  Sixteen
hectares of lagoons representing sixty million gallons of storage capacity pro-
vided temporary relief during  the winter months  of 1968 - 1969.  By the spring
of 1969, anaerobic  decomposition of  the waste activated sludge stored in the
lagoons  created serious odor problems.  Neither  the FDI units nor the temporary
lagoons  provided an acceptable  solution to the sludge disposal  problem.  Conse-
quently, a third alternative,  land application of vacuum filter cake, was ini-
tiated in  May of 1969.

-------
Land application of  vacuum filter cake was originally conceived to be a
temporary expedient  until the FDI units could be restored to their design
capability,  By 1971  it was apparent that the cost of continued operation
and maintenance of the FDI units would be prohibitive.  The most serious
problems occurred when the FDI units were being operated in the incinera-
tion mode.  Although  from a maintenance standpoint it would have been de-
sirable to  operate the units in the drying mode only, this was not possible
for  several reasons.  The primary fuel source for the operation of the units
was  natural gas with  No. 2 diesel as a standby fuel.   During the winter of
 1969-1970,  natural gas service was curtailed on many occasions, and Metro
 did  not have a sufficient allocation of standby fuel.  This limited fuel
 supply forced the District to incinerate sludge for its caloric value as
a  substitute for commercial  fuel.

It was originally anticipated that the City and County of Denver Parks De-
partment would use the dry sludge as a fertilizer.   The physical character-
istics of the heat dried sludge were such that it could not be handled with
commercial  fertilizer spreaders without causing dust problems.  For this
reason the Denver Parks Department in the fall of 1969 refused to accept
any additional  dried sludge.   As no other large customer of dried sludge
existed in the area, it was  necessary to cease drying and revert back to
the incineration mode even during periods when adequate fuel was available
for drying.

Operational limitations encountered during the incineration mode were odors,
as well as particulate and opacity air pollution problems.   When the FDI
units were initially installed in 1966 they met all  existing Colorado air
pollution standards.  In 1970 these standards were revised drastically to
reduce stack emission concentrations from stationary sources.   During 1971
the FDI units were operated  under a temporary variance while modifications
were being made to meet the new standards.  It soon  became obvious that the
FDI units could not be economically modified to comply with the new stand-
ards.  Because of air pollution, mechanical  and fuel  problems, the FDI units
were permanently shut down in August of 1971.  Between May of 1969 and Au-
gust of 1971 the FDI units and the land application  of filter cake were op-
erated concurrently.  From August of 1971 to the present time the only me
of sludge disposal  used by Metro has been land application.

-------
                  EVALUATION OF LAND APPLICATION TECHNOLOGY
In 1969 Metro acquired 64.8 hectares of land from the City and County of Den-
ver.  This land had been sold to the City and County of Denver by the federal
government for the purpose of solids waste disposal.  The land is located 42
kilometers southeast of the Metro treatment plant and was part of the LBR
(Lowry Bombing Range) (Fig. 2).  The vegetation on this site was natural pas-
ture grass typical of the range land of Colorado.  During 1969 and 1970 the
vacuum filter cake sludge, which could not be processed by the FDI units, was
transported by truck to the LBR site.  The vacuum filtered sludge contained
15% TS and was transported in open 10 cubic meter trucks equipped with special
rubber seals to prevent leakage during transport.

In 1969 and 1970 two methods of operation were utilized, one for dry weather
and the second for wet weather.  Metro hired a contractor to perform the ne-
cessary work under both modes of operation.  The transportation of vacuum fil-
ter cake was the same for both dry and wet weather operations.  During dry
weather the sludge was tail gated directly from the transport vehicle onto the
                                                          Snftfff
 Fig. 1-Filter cake sludge is tail gated onto soil surface.

-------
                                                    /
                                 CO
                                 evj
                    1-70
                                              f
                                              t—Metro Treatment Plant
                       L—L/
                                                                   ..n
                                                         ludge  Recycle-
                                                                   1-70
          5 miles /  —
                   •.
Denver City
Limit
Fig. 2-Location map of Lowry Bombing Range sludge recycle site.

-------
surface of the soil,  A D-6 Caterpiller equipped with a front mount blade
was then used to spread the sludge evenly over the surface of the soil  to  a
depth of approximately 2.5 centimeters,  The sludge was then  allowed to dry
for 24 hours.  After the sludge had dried, an industrial-type (1.8 meter
wide) rototiller with a depth capability of 45,7 centimeters  incorporated
the sludge into the soil.   This operation was not always  satisfactory for
the following reasons:

   A)  Rocks over 12.7 centimeters in diameter would lodge in the tiller
       mechanism, causing shear pins and drive chains to  fail; thus, ren-
       dering the unit inoperable.

   B)  Dense vegetation over 1.2 meters tall would wrap up in the tiller
       mechanism and plug the unit.

   C)  Wet soil would clog the tiller mechanism with mud  and  the  unit
       would become inoperable.

During warm weather, land application was cyclical, three weeks on and three
weeks off, which coincided with shutdown and routine maintenance  of the FDI
units.  In wet weather the sludge was dumped directly onto the surface of  the
soil, and D-8 Caterpiller tractors with front mounted blades  would intermix
the sludge with the soil.   A satisfactory mix was accomplished when a ratio
of five or more parts of soil were mixed with one part of sludge.  However,
during the winter months when the soil had frozen, the mixing of  sludge and
soil was extremely difficult.  It then became necessary to provide a ripper
behind the D-8 Caterpiller in order to keep ahead of the  soil freezing prob-
lem.  It was necessary to work 24 hours a day, 7 days a week.  During winter
weather operation, the sludge was intermixed into the soil in the rolling
topography which lends itself to this type of operation.   In  these areas
large quantities of soil for intermixing with sludge were available within
a relatively short distance from the application site.  Of the 64.8 hectares
originally acquired 36.4 hectares were actually utilized  for  sludge incorpor-
ation.  A total of 30,600 dry metric tons were applied to the site in 1969
and 1970 for a loading rate of approximately 840 dry metric tons  per hectare.
The exact sludge loadings to the area in 1969-1970 could  not  be determined
because of different application methods used at different seasons.

Peripheral surface water channels were dug around the 64.8 hectare site to re-
tain the water which ran off during snow or rain storms.   During  severe storms
the collection channels proved inadequate to contain all  of the runoff. Metro
and the State Health Department sampled this runoff downstream of the site
during these periods.  Analysis of the runoff samples did not indicate the
presence of contaminants from the land application site.

In April of 1970 Metro ceased application of sludge to the site because of
concern that the high loading rates might have an adverse effect  on soil pro-
ductivity and erosion.  The site was then graded using a  rubber tired scraper
(between the fall of 1970 and the spring of 1971).  In the fall of 1971 the
site was seeded using Brome and Crested Wheat grasses.  During 1972 high
winds and generally dry conditions hindered growth of the grasses planted.
In the spring of 1972 the area was reseeded.  Because vegetative  coverage

-------
was incomplete, the area was again reseeded in the fall of 1972 with tiie
same mixture of grasses.  By the spring of 1973 vegetative coverage exceeded
50% of the total area.  Supplementary seedings were conducted during the fall
of 1973 and spring of 1974.  By the spring of 1975 vegetative cover was vir-
tually complete.  The complete revegetation process took three years.   Reve-
getation was difficult because top soil had been removed and replaced with
subsoil (no sludge was incorporated into the soil) and moisture was marginal.
Annual precipitation averages 35.6 centimeters per year and irrigation water
was not available.

The major problem involved in the 1969-1970 operation was vulnerability to
adverse climatic conditions.  There were several occasions during the winter
of 1969 and 1970 when snow blizzards required cessation of sludge incorpora-
tion.  The equipment operators and truck drivers could not reach the site be-
cause of snowdrifts.  The dry weather operation costs were much lower than
the wet weather costs.  During dry weather one rototiller could incorporate
the total daily sludge production.  Six D-8 Caterpillers were required to
mix the total sludge production under the wet weather operations.

Recognizing that the FDI units could not be modified and operated to comply
with the Colorado air pollution standards, Metro in 1971 revised the land ap-
plication operation to provide for a continuous year-round disposal of the
total sludge generated.  For this purpose, Metro received permission to use
an additional 259.2 hectares of pasture land at the LBR from the City and
County of Denver.

Based on the experiences during 1969 and 1970 with the land application of
sludge, several changes in sludge application methodology were adopted.  Metro
purchased the equipment necessary for the land application system, and uti-
lized District personnel to operate this equipment.  The method of operation
consisted of transporting the filter cake from the treatment plant to the LBR
in the same type of vehicle used in the previous operation.  These vehicles
were equipped with special seals to prevent accidental leakage during trans-
port.  A ramp was constructed at the application site which allowed the trans-
port vehicles to transfer the sludge directly into spreaders.  The 10 cubic
meter farm manure spreaders were sized to accommodate one truckload of sludge.
The spreaders were modified with special seals to handle the relatively wet
vacuum filter cake to keep the sludge from flowing onto areas where it was
not desired (Fig. 3).  Special lighting was provided at the ramp to allow for
operation 24 hours per day with two spreaders and one tractor.  A standby
tractor was rented for the purpose of allowing the primary unit to be serviced;
thus, enabling operations to continue 7 days a week.  Sludge was spread onto
the surface of the grass and usually dried within one-half hour after appli-
cation.  After each application of 6.7 dry metric tons per hectare a spike
tooth harrow was used to break up any large particles into fine particles.
Cattle continued to graze the pasture during this operation.

In 1971, 115 hectares of the 260 hectares acquired earlier were used for
sludge application.  A total of 8,539 dry metric tons of solids were applied
to the site resulting in a loading of approximately 74 dry tons per hectare.
Soil  and surface water monitoring during 1971 indicated that there had been
                                       8

-------
 Fig.  3-Sludge  being  transferred to 10 cubic meter manure spreaders-.
no contamination as a result of Metro's operation at this site.  A major
advantage of this method was that the operation did not disturb the native
vegetation.  Based on visual observations the vegetative production at this
site improved compared to the surrounding area that did not receive sludge
applications.  Another major advantage of this operation was that it was
far less expensive than the incinerator drying operation (Table 1).  This
method was also environmentally acceptable from the standpoint of soil
conservation, air pollution and odor problems.

At the direction of the District Board of Directors, in November of 1972
Metro entered into a two year contract with a private contractor, Landfill,
Inc. to provide services for land application of sludge utilizing the same
technology which Metro staff had developed.   Concurrently,  Metro acquired
an additional 260 hectares of land from the City and County of Denver for
a total of 583.2 hectares.

The contractor utilized larger transport vehicles,  30 cubic meter units, and
constructed a large sludge storage hopper to store  sludge from the transport
vehicles until  it could be transferred into  the spreader trucks (Fig.  4).
The spreaders used by the contractor were also larger (15 cubic meters)  than
those used during the previous operation (Fig. 5).   Each spreader was  mounted
on a large truck chassis previously used in  open coal  pit mining (23,622 kilo-
gram rear axle capacity).   The farm fertilizer spreaders were  modified to

-------
  able 1-Comparison  of  incinerator versus land  application sludge disposal
                                       costs  (1971)
                                                               iot«i o ( H
 Sludat              Operations and
disposal    Tons     maintenance cost  Unit 0 t M cost Capita Mmprovemwt   capital costs    Total  unit
                                                 cost S/year        $/year      costs $/ton   differentiation
 method    disposed
            Vyear
                           $/ton
Sludge
Indn.
          14,649
            351.900
                           24.00
                                         122.000
                                                       473.900
                                                                     32.35
                                                                   721 higher than
                                                                   land application
Land
appl.
15.05d
257.700
                           17.11
                                          25.000
                                                       282.700
                                                                     18.77
Total      29.707
            609,600
                                     20.52
                                         147,000
                                                                 756,600
                                                                              25.46
 Fig.  4-Transport  vehicle dumping  into  sludge  storage hopper.
                                               10

-------
                                                                             -
       •  •«. ••..***-*••
         «_..





Fig. 5-Modified fertilizer spreader spreading sludge.
handle the relatively wet filter cake.   During the fall  and winter of 1971
and 1972 the contractor spread the sludge thinly over the grassland.   In
early spring of 1972 the contractor experienced difficulty with access to
the field.  As a result, large quantities of vacuum filter cake were  stock-
piled to a depth of 1.2 meters in a depression near a dry stream bed  on the
site.  After completion of the stockpiling of filter cake, snowstorms oc-
curred which covered the stockpiled filter cake.  Metro inspectors were un-
aware of the unauthorized modification  of the method previously agreed upon.
As the snow began to melt, the stockpiled sludge began to decompose creating
odor nuisances to people living in the  area adjacent to the site.   During
late spring when the area had dried, small  smoldering fires started in the
areas which had received many consecutive sludge applications,  a result of
careless smokers and heavy equipment operating in the area.  The smoldering
fires were difficult to extinguish particularly during high winds.

Complaints to the Arapahoe County Commissioners made by residents  living in
the adjacent area resulted in a Public  Hearing on June 20, 1972.  At  the Pub-
lic Hearing Metro proposed a new method of land application to  eliminate the
odor and fire hazards previously experienced.  This proposal  was approved by
the County Commissioners and implementation began in June of 1972.
                                      11

-------

                   &**£* •«*»»
«S€
Fig.  6-Mold board  plow  incorporating sludge.
The revised method consisted of applying the filter cake to the land at a
depth of 5 to 8 centimeters  (approximately 74 dry metric tons per hectare),
and within six hours  of application  incorporating the sludge to a depth of
25 centimeters using  a  41  centimeter mold board plow or a 76 centimeter disc
plow (Fig. 6).  After sludge incorporation the soil was tilled with an off-
set disc several  times  until a suitable seed bed had been prepared.  As the
native vegetation is  disturbed by this method the soil is seeded with wheat
or other forage crops such as sudan  or oats to provide a vegetative cover
protect the soil  from wind and water erosion.  Because germination is inhi-
bited if the soil is  seeded immediately after sludge incorporation, the soil
is allowed to set or  incubate for 2  months before seeding.  With the assis-
tance of the Soil Conservation Service staff a plan was developed to estab-
lish permanent contours on the entire application site.  One or more crops
are raised each year  to provide  food for the grazing cat-
soil erosion.

Since 1972 this method has been  providing satisfactory control of the odor
and fire problems previously experienced.  While this method is satisfactory
during dry weather, special  modifications had to be adapted during winter op-
erations   In the fall  of 1972 an additional 260 hectares were acquired  for
the expressed purpose of inclement weather  incorporation.

                                    12

-------
spread on the land by tailgating to a depth of 60 centimeters  and  intermixed
with the soil at a ratio of five parts soil to one part sludge,  Since  1973
the inclement weather site has been prepared in advance by bench and  terrac-
ing the area.  Sludge loadings to the inclement weather site  have  exceeded
670 dry metric tons per hectare per year.   Each inclement weather  site  is
loaded only once.  Inclement weather application generally takes place  dur-
ing December, January and February depending upon the severity of  the winter.
During the relatively mild, dry winter of 1974-1975 the inclement  weather
site was required for only 30 days during January and February.
                                     13

-------
          EVALUATION OF SLUDGE EFFECTS ON THE LOWRY BOMBING RANGE


TYPE OF SLUDGE

If sewage sludge is to be utilized as a soil conditioner or fertilizer,  pa-
rameters such as nutrient content, metals, conductivity, pH and organic  mat-
ter should be known in order to evaluate effects on subsequent plant growth.
When sludge is applied to soil, one of its immediate benefits is its N (ni-
trogen) and P (phosphorous) content.  Because much of the N is tied up in
the organic fraction it becomes a valuable source of slow release N.  In ad-
dition to macro-nutrients such as N and P, sludge is a valuable source of
micro-nutrients such as Zn (zinc), Cu (copper), B (boron) and Mo (molybdenum)
when applied at low rates.  The stable organic matter contained in sludge be-
comes a benefit by acting as a soil conditioner, which increases soil  CEC
(cation exchange capacity), water holding capacity, infiltration rates and
the general tilth of the soil.

Potential problems that could arise from heavy applications of sewage sludge
include inhibition of germination from excess salts, phytotoxicity from  heavy
metals, excess N and P, pathogens, and odors.

The sludge sources that comprised the vacuum filter cake incorporated into
the soil at the LBR included:

   A)  Raw primary sludge - 40% of total.

   B)  Waste activated sludge - 45% of total.

   C)  Anaerobically digested primary sludge - 15% of total.

This sludge mixture was dewatered by applying FeCIS (8-12!% of dry weight) and
slaked lime (20-30% of dry weight).  In the fall of 1973, cationic polymers
were substituted in part for the FeCl3 and lime.  The amount  of polymer  re-
quired (4.5 to 6.8 kg/0.9 metric ton dry weight) was insignificant compared
with the approximate 30% chemicals added to the vacuum filter feed when  FeCIS
and lime were applied.   Thus, the polymer conditioned vacuum  filter cake re-
presents the average chemical composition of the sludge without chemicals.
Summarized in Table 2 are the arithmetic means and standard deviations for
all  of the chemical constituents analyzed in both types of vacuum filter cake
for the years 1972 through 1975.

Major differences between the two types of filter cake are as follows:

   1.   pH;   FeCl3 and lime cake =11,4 versus 6.6 for polymer cake.


                                     14

-------
Table 2-A comparison of chemical  composition  of ferric  chloride  and  lime
                treated vacuum filter cake with polymer conditioned
                        vacuum filter cake (1972-1975 data)
Analysis Units
pH Units
Volatile frac-
tion % of TS
Conductivity umho/cm
Ag mg/kg-dry wt.
As
B
Ba
Bi
Ca
Cd
Co
Cr
Cu
Fe
Hg
K
Li
Mn
Mo
H (TKN)
Na
Ni
P
Pb
Se
Sn
Sr
T1
U
V
Y
Zn
Zr
Vacuum filter
W/FeCl3 + 1
Mean
11.4
54.9
9,790
' 51
17
53.5
440
10
87,380
18.9
77
480
770
34,160
4.7
4,800
20
355
19.3
38,640
6,300
290
16,700
491
7
135
310
1,275
8
70
25
1,305
153
cake
ime
+_ S.D.*
0.9
6.2
3,087
22
-
12.0
141
-
26,720
14.2
32
262
295
9,330
3.8
-
-
160
7.0
8,230
-
129
5,400
312
-
17
128
206
-
-
6
719
56
Vacuum filter cake
W/polymer
Mean
6.6
69.6
4,820
-
-
-
-
21 ,800
13.0
-
711
924
7,120
-
-
-
215
-
56,415
-
344
21,570
568
-
-
-
-
-
-
-
1,864
—
+_ S.D*
0.8
5.6
1,820
-
-
-
-
11,690
10.4
-
346
234
2,860
-
-
-
112
-
11 .930
-
132
10,700
199
-
-
-
-
-
-
-
224
—
* Standard Deviation
                                      15

-------
    2.   Percent  volatile solids:  FeClS and lime cake = 54.9% versus 69.6%
         for  polymer cake.

    3.   Electrical conductivity  (umho/cm):  FeCl3 and lime cake = 9,790
         versus  4,820 for polymer cake,

    4.   Calcium:   FeCl3 and lime cake = 87,380 ppm versus 21,800 ppm for
         polymer cake (dry weight basis).

With  regard  to  plant nutrients, the high pH of the FeClS and lime treated
sludge  resulted in significant  losses of volatile ammonia (NH3), as was evi-
dent  by the  strongly pungent NH3 odors prevalent in the vacuum filter process
building  during treatment with  FeClS and lime.  Although dilution of the fil-
ter feed  with chemical may have accounted for part of the reduction in N con-
centration (from  5.67% N in polymer cake to 3.86% N in FeCl3 + lime cake) the
32% loss  in  TKN (total Kjeldahl nitrogen) was in great part due to NH3 volati-
lization.  The  22% reduction in P concentrations is attributable to the dilu-
tion  effect  with  additions of FeClS and lime.

Average sludge  loadings have been at the rate of 67.2 metric tons/hectare/-
year  which would  mean that approximately 2,600 kilograms of N/hectare/year
have  been applied with the addition of FeCl3 and lime cake compared to 3,800
kilograms of N/hectare/year for the polymer cake.  Sludge has been applied an-
nually  to much  of the area since 1969; thus, N has been applied far in excess
of  crop needs.

SOIL  EFFECTS OF SLUDGE DISPOSAL AT THE LOWRY BOMBING RANGE

The LBR sludge  and disposal area is located east of Denver in Arapahoe County,
Colorado.  The  county has a warm, semi-arid climate that is typical  of the
High  Plains; thus, rainfall averages 35.6 centimeters,  while the average annual
temperature  is  about 10°C.

The dominant soils at the LBR are the Fondis and Renohill  series.   The Fondis
soils are deep  well drained soils located on uplands, and formed from loessol
deposits overlying the Dawson formation (Pleistocene Age)  (1).   The  Fondis sur-
face  soil is about 10 centimeters thick, free of lime,  very dark grayish-brown
and silt loam to  silty clay loam in texture.   The subsoil  is 102 to 114 centi-
meters  thick, contains free lime, dark yellowish brown  and silt loam to clay
in  texture.   The  Fondis soils have moderately slow permeability, slow internal
drainage and high available water holding capacity.   The Renohill  series which
has developed on the Dawson formation is a moderately deep well drained soil
(1).  The surface layer is about 10 centimeters  thick,  free of lime, and is a
dark  brown loam.  The subsurface soil  is approximately  63 centimeters thick,
contains free lime,  dark brown to dark yellowish brown  in color, and ranges
from a  loam  to silty clay loam in texture.   Renohill  soils have medium inter-
nal  drainage, moderately slow to slow permeability and  moderate water holding
capacity.

Starting in   1972 an attempt was made to monitor  and evaluate the degree of
possible soil pollution from excessive salts  or  heavy metals after continuous
sludge applications.   A general  survey, which examined  a number of soil  cores


                                      16

-------
to a depth of 0.9 meters was taken semi-annually.   Soil  samples,  which repre-
sent only one sample point from each area,  were analyzed for pH,  conductivity,
nitrate nitrogen (N03-N), ammonium nitrogen (NH4-N), sodium bicarbonate extrac-
table P, ammonium acetate extractable K,  chlorides  (Cl)  and diethlenetriamime-
pentacedic acid (DTPA)  extractable Zn,  Fe,  Cu and  Mn (see Appendix A).

Site 1 was a control area, while sites  2  through 7  were  areas that had received
varying amounts of sludge (see Fig.  7).

Soil samples collected  in November of 1974  had total sludge loadings varying
from 0 to 542 metric tons/hectare.  Heavy metal analysis and pH for surface
soils (0 - 15.24 cm) from the November  1974 sampling are shown in  Table 3.   Sub-
surface soils are not included in the table since  there  was no apparent leach-
ing of metals below the surface (see Appendix A for subsoil analysis).


Table 3-Concentrations  of DTPA extractable  Zn, Fe,  Cu, Mn and pH  from sludge
         additions to surface soils  (0-15.24 cm) at the  Lowry Bombing Range*
Site 1
1A
IB
1C
?A
6A
66
3A
38
3C
4C
2C
2B
5C
4A
4B
SB
5A

7
7
pH
.5
.6
7.1
7
7
7
7
6
7
7
6
7
7
7
7
7
7
.5
.5
.9
.1
.4
.7
.5
.5
.3
.0
.1
.3
.8
.3
Zn
0.
0.
0.
10.
10.
15.
41.
33.
16.
56.
19.
8.
85.
28.
15.
45.
68.
8
6
6
5
2
2
5
0
0
0
0
3
0
0
5
0
0
8
6
15
Fe
.9
.0
.2
20.2
21
.6
17. a
59
25
6d
67
64
24
8
65
30
71
72
.0
.7
.0
.0
.5
.4
.8
.0
.5
.0
.0
Cu
0.
0.
0.
5.
6.
9.
17.
12.
12.
35.
5.
5.
4.
12.
7.
42.
10.
7
6
7
4
8
6
5
6
5
0
9
7
0
0
4
0
0
Mn
13.
6.
13.
17.
8.
10.
18.
98.
99.
31.
34.
15.
85.
60.
15.
26.
26.
Estimated tons of
sludge applied/hectare (dry wt.)
7
9
2
0
5
0
5
0
0
0
0
0
0
0
0
0
0
0
0
0
74
74
130
143
143
143
184
195
202
267
323
381
461
542
         *So11s sampled 1n November 1974.
The concentration of the various chemical constituents examined did not reflect
the estimated sludge loadings to each site; thus, it can be concluded that the
sludge application is extremely variable, or that the sludge soil  mix is not
adequate.

An examination of data from site 5C demonstrates the extreme heterogeneity of
the sludge-soil mix within one field.  Analysis of a soil sample taken in May
of 1974 is compared with the analysis of a soil sample from the same field col-
lected in November of 1974 (Table 4).  There were no sludge applications to

                                      17

-------
CXI

-------
  this field between  these sampling dates.   None of the chemical  constituents
  examined are similar.
  Table  4-Comparison  of chemical  constituents  of soil  samples  from site  5C  sampled
                            in May Iy7t and  Novemuer  li»74
       Analysis
Units
May 1974
                                 November 1974
PH
Conductivity
Zn (DTPA)
Fe (DTPA)
Cu (DTPA)
Mn (DTPA)
H03-N
MK4-N
TKN
P
K
units
mmho
mg/kg
rag/ kg
mg/kg
mg/kg
mg/kg
mg/kg
%
mg/kg
mg/kg
7.4
3.6
.95
6.2
1.47
8.50
240.0
12.0
0.31
385.0
358.0
7.0
15.4
85.0
8.8
4.0
85.0
1000.0
11.0
0.52
450.0
480.0
 The range in  DTPA extractable metal  content  for  Zn  (See  Table  3)  is  from 0.6
 Ppm in  the control  to  a  high  of 85.0 ppm  at  a  267 metric ton/hectare applica-
 tion, while Cu  ranges  from 0.6 ppm in the control to  42.0 ppm  at  a 461  metric
 ton/hectare application.   It  is interesting  to note that the soil sample from
 site 5C  (November 1974 sampling)  apparently  had  the highest loading  of  sludge,
 as  can  be seen  from the  high  Zn,  Mn,  N, P and  conductivity levels (see  Tables
 3 and 4);  however,  the concentration  of DTPA extractable Cu is quite low.  The
 low extractability  of  Cu  in this  sample is probably a reflection  of  the high
 absorption  or chelating  capacity  of  the organic matter for Cu.  Whether this
 statement  is true  is unknown  since the total metal content of  the soil  samples
 was not determined.  However,  this example tends to point out  the falibility
 in  trying  to analyze the  toxic  metal  status of a soil  when employing an  ex-
 traction  technique  which  only  examines some fraction of  the total  metal  present,
 Whether the levels  of  metals encountered  in this survey  (many of which  are re-
 latively  high)  could produce phytotoxic effects on the plants growing on these
 soils is  unknown, since plants  growing on these sites  were not collected for
 analysis of metals, nor were yield determinations made.    It can only be noted
 that the wheat  crop growing on  these  sites appeared  to be healthy.

Soil pH at the  Lowry Bombing Range naturally ranges  from about 7.0 to 8.0.
Sludge  additions had little effect on lowering  the soil  pH, which  reflects the
saturation with calcium carbonates in these soils.

Soil conductivity shown in Table 5 is like the  metal data, extremely  variable,

                                       19

-------
ranging from a low of 0.5  mmho/cm  in  the control  area  to a  high of  15 mmho/-
cm at site 5C.  About one-third  of the  sites with' sludge applications showed
conductivity levels from 4 to 14 mmho/cm which  could be considered  injurious
to some of the crops grown in this area.

Table 5-Concentrations of  N03-N, NH+-N, TKN, P,  K and  conductivity  from sludge
          additions to surface soil!  (0-15.24 cm)  of the Lowry Bombing  Range
ma/ka (dry vyt.) %
Site *
1A
IB
1C
2A
6A
6B
3A
3B
3C
4C
2C
2B
5C
4A
4B
t.B
5A
N03-N
1
1
1
2
46
32
570
600
400
330
435
6
1000
220
160
3aO
680
NH^-H
21
14
10
12
20
20
32
30
19
9
47
10
11
19
23
22
32
TKN
.116
.159
.078
.174
.136
.145
.292
.238
.243
.280
.197
.150
.520
.219
.162
.297
.341
ing/ kg
(dry wt.)
P
22
4
17
80
125
175
385
325
225
440
120
72
450
16b
115
345
450
ijimho
K Conductivity
393
325
265
650
425
342
700
1080
700
580
405
393
480
418
405
363
363
.6
.5
1.1
1.2
1.8
1.4
8.7
9.2
1.7
6.8
8.7
.9
15.4
.9
2.8
4.1
8.5
Estimated tons/ha
applied
(dry wt.)
0
0
0
74
74
130
143
143
143
184
195
202
267
323
381
461
542
 Soils  in  this  area  are  naturally high in K and rarely require any K fertiliza-
 tion for  crop  production.   The  addition of sludge has increased the extractable
 K levels  in all  cases  (see  Table 5), but not to a detrimental level.

 Sludge applications have  increased  the available P content to high levels
 (see Table 4), but  it  is  doubtful that these levels are detrimental to crop
 growth since there  is  a more than adequate supply of available Zn, Cu, Mn and
 Fe which  would tend to offset any P induced Zn, Cu, Mn or Fe deficiencies.

 Two factors play a  role in  the  extreme -variability of N content of the sludged
 soils at the LBR.  The first factor is the extreme heterogeneity  of  tne  sludge-
 soil mixture which  has already  been noted. The  second factor is that  the  sludge
 itself is extremely variable.  From Table  1 it  can be seen that the  dewatering
 process used at the treatment plant (FeCls + lime versus  polymer  will affect
 the N content of the sludge; thus  the  average N content of the sludge varies
 from about 3% to 6%.
                                       20

-------
Continuous sludge applications  since  1969  have  increased  the  N  content  of  the
soil  (see Table 6)  to excessive levels,  beyond  any  capacity for crop  removal.
Immediately available N  (NOs-N  + NH4-N)  ranges  from a  low of  31,4  kilograms
per hectare at site 2A to a  high of 113^.3 kilograms per  hectare at site 5C.
If only 3/o of the TKN becomes available  for plant uptake  during the growing
season, then site 2A contains a total  of 135.4  kilograms  per  hectare  of avail-
able N while site 5C contains 1444 kilograms per hectare.  Because of these
high rates, N has leached below the rooting zone.   Summarized in Table  6 are
N03-N, NH/j-N and TKN data for the 61  to  91 centimeter  depth.   The  leaching
rates do not appear to be excessive,  and it is  doubtful  that  N03 from sludge
applications would ever  pollute the ground water.   Rainwater  in this  area  is
insufficient (approximately  36  centimeters per  year) to  percolate  to  any sig-
nificant depth, and potable  water is  from  100 meters to  300 meters deep which
is protected by impervious stratum within  the Dawson formation.


Table 6-Concentrations of NOj-N, NHL-N and TKN  from subsurface  soils  (61 to  91
                         cm  depth) at the  Lowry Bombing  Range.
ppm
Site 1
1A
IB
1C
2A
6A
6B
3A
3B
3C
4C
2C
2B
5C
4A
4B
SB
5A
N03-N
1
1
13
5
1
2
42
33
28
34
3
1
21
3
25
61
51
NH4-N
7
15
5
10
15
15
7
7
13
9
11
7
14
19
21
19
19
I
TKN
.029
.028
.024
.033
.026
.022
.043
.063
.060
.034
.038
.027
.032
.033
.034
.030
.035
Cl
<2
2
22
2
8
25
15
8
5
22
2
10
2
20
8
5
8
Estimated tons/ha
applied (dry wt. )
0
0
0
74
74
130
143
143
143
184
195
202
267
323
381
461
542
                                      21

-------
Grab samples of soil  and leaf tissue from winter wheat (Wichita)  were col-
lected from the LBR on May 31, 1974,  Results  of total metal  analysis are
shown in Table 7,   The plant and soil  samples  were digested in a  nitric-per-
chloric acid mixture and metals determined using atomic absorption.   The
plant samples were not washed prior to analysis, nor was background  correc-
tion applied during the analysis of Cd,  Pb or  Ni.   However, none  of  the me-
tal concentrations reported in Table 7 would be  considered out of the normal
elemental composition range for plant materials,

Table 7-Total metal composition of soil  and wheat from the Lowry  Bombing Range
Site 1
Soils:
1
2
3
4
5
6
Plant tissue:
1
2
3
4
5
6

Zn

59
53
125
60
80
205

19
16
23
46
56
55

Cu

24
18
40
22
25
54

5.6
8.4
10.6
12.7
15.4
36.2
mg/ktj_ (dry wt.
Ni

16
16
25
20
20
21

5.5
4.0
4.6
4.8
5.6
8.6
)
Cd

ND*
NO
.45
.35
.30
1.20

.12
.12
.19
.41
.22
.34

Pb

25
20
30
20
25
48

5.7
3.4
3.3
3.3
6.6
5.2
           *ND - not detected
                                      22

-------
                           RESEARCH  AND  DEVELOPMENT


By 1971,  it had become apparent that land  application of  filter cake was not
to be a temporary expedient in  place of  incineration, but a  long  term neces-
sity.  Metro staff therefore contacted the Agronomy  Department of Colorado
State University (CSU) at Fort  Collins,  Colorado  to  investigate the various
aspects of sludge loading rates,  as  well as other conditions  necessary  for
beneficial utilization of nutrients  in sewage  sludge.

The goals of this research effort included:

   1.  Investigation of alternative  land application and  incorporation
       methods.

   2.  Environmental monitoring of soil, plants,  ground water and air.

   3.  Evaluation of various crops that  could  benefit from  optimal loadings
       of sludge to soil.

The  information from this research was to  be made available to that segment
of the farm community wishing to apply sludge  to their  land in the proper
season and amount.

In 1971 a contract was signed with the CSU Department of Agronomy and Danford
Champ!in  Farms  for a 0.81 hectare research site at Watkins, Colorado  to inves-
tigate the effects of various sludge loadings  on plant germination and growth.
Results from this experiment led to greenhouse experiments  using a range of
crops including millet, wheat and sorghum  sudangrass hybrid.  These crops  were
subjected to various  sludge loadings and various incubation periods between
sludge application and seeding.

On the basis of results obtained from these projects as well as recommendations
of Metro's consulting engineers to  utilize the semi-arid climate and evapora-
tion capacity  in  Colorado  for air drying,   an investigation of air drying of an-
aerobically digested  sludge in drying basins at the CSU agronomy farm at Fort
Collins was initiated in  1973.

Obnoxious odors experienced during  some of the early research work at Watkins
led  to investigation  of  various  subsurface injection devices which would in-
ject liquid sludge  beneath  the soil  surface to avoid aesthetic and odor prob-
lems.  Therefore,  liquid  sludge was  injected into the  soi!  at Watkins, Colo-
rado.  Two  injection  devices were used, one owned by Danford Champlin  farms
and  one  designed by James  Smith  of  CSU; both devices worked well  and no odor
problems  developed  when  these  devices were used.


                                      23

-------
LAND APPLICATION OF  METRO SEWAGE SLUDGE AT WATKINS,  COLORADO:   EFFECT
 ON GROWTH AND CHEMICAL COMPOSITION  OF PLANTS*


Objectives of the Study

1.  To  determine the maximum application rate of  the Metro sewage sludge
    to  the sandy soils  of western Adams County, Colorado consistent with
    continued crop productivity without causing heavy metal, organic or
    pathogenic pollution  of soil or water,

2.  To  determine the extent of leaching and/or accumulation of  substances
    derived from sewage sludge applied to soil.


Materials  and Methods

A field study was set up  on a Truckton sandy loam soil  in western Adams
County.  Soil  characteristics before  sludge application are shown in Table
8.  These  are deep soils  with loamy  sand surface  layers and loamy subsoils
that grade into sand at depths of 50  to 76 centimeters.  They are on ter-
races and  uplands,  and  are developed  from sandy alluvium washed from the
arkosic  sandstones  to the south.  Wind has reworked  the sandy alluvium in
most areas developing an  undulating  to rolling topography.  About one-thir
of the  area of this soil  has slopes  less than 3%  and two-thirds is rolling
and slopes an  average 6%.

   Table 8-Characteristics of the Truckton loamy  sand used in the study


                     ~~a)       b)          F1eld
                   -        X     Textural"'     CECU'       Infiltration     0 M c)
                  s*lt    Clay      Class     m.e./lOO gtn     rate cm/hr      j '
                                                                               rd
           Sand       		
                    14      8    Loamy Sand      5.2           12.7       TTj


                                     Extractable - ppm


           Oj-Nd)       i0        -f>       1°9)        Cu9)        Feg)        Mng)
           3          10        12°         2          1         12         12
            a) Pipette Method. OH oxidized by H202, dispersed with Calgon.
            b  Determined by the ammonium acetate described by Jackson.
            c  Determined by the chromic acid method described by Jackson.
            d  Determined by the phenoldisalfonic acid method described by Jackson.
            e) Determined by the ascorbic acid method described by vatanabe et al .
            f  Determined by the ammonium acetate method described by Pratt."
            g) Determined by the DTPA method described by Lindsay et al..
*This  research was conducted for Metro  by B.R. Sabey and W. Hart of Colorado
 State University, parts  of which were  published  by them in the Journal  of
 Environmental Quality,  1975.  4:2:252:256.
                                        24

-------
Plots (3 meters  x  9.6 meters) were  prepared by leveling  the  areas and build-
ing levees around  each individual plot  sufficient to contain the applied li-
quid sludge.   Measured quantities of  sewage sludge  (approximately 5% solids)
were pumped  from tank trucks onto the plots on May  18 and  19,  1971,    An
analysis of  the  sludge is shown  in  Table 9.  The liquid  sludge as applied was
approximately  50%  primary anaerobically digested and 50% aerobically digested
sludge.

Five ratios  of liquid sludge ranging  from 0 to 40.6 centimeters in depth were
applied to each  cropping situation  in a single application prior to seedbed
preparation.   Amounts of liquid  sludge  applied were equivalent to 0, 25, 50,
100 and 125  metric tons/ha  (dry  weight).  Three cropping situations - fallow,
sorghum sudangrass hybrid (sorghum  bicolor x s. sudanense) CV.  NB 230 S,
and millet  (Panicum milacium L.)  CV Leonard were initially used.  Each treat-
ment was replicated four times in a randomized block design  giving a total of
60 plots.   In  addition to these  60  plots, 12 more plots  received applications
of filter cake sludge varying from  27 metric tons to 112 metric tons/ha  (dry
weight).  Plot design layout with loading rates is  shown in  Fig. 8.
Table  9-Typical  analysis of  anaerobically and aerobically digested sewage
   sludge  produced by Metropolitan  Denver Sewage  Disposal District No.  1
Anaerobically digested
primary sludge
total solids-b.7?
t Irrnent
N (organic)*
p..
K"
Ti***
Cr
Hn
Fe
Co
N1
Cu
Zn
Br
Rb
Sr
r
Zr
Mo
AG
Cd
Sn
Ba
Pb
U
As
Se
Dry weight
2.8
1.3
1.1
0.18
0.021
0.035
1.7
0.001
0.0?4
0.13
0.40
0.002
0.004
0.037
O.C10
0.041
0.006
0.007
0.003
0.020
0.17
0.17
0.002
-
-
mg/1
Wet weight
1600
741
627
103
12
20
970
0.60
14
74
228
1.1
2.3
22
5.7
23
3.4
4.0
1.7
11
97
97
1.1
-
-
Aerobically digested
activated sludge
	 total solid-,-4.4%
1
Dry weight Wet
6.6
3.1
1.3
0.18
0.065
0.035
1.0
0.001
0.025
0.23
0.48
0.003
0.003
0.023
0.004
0.014
0.001
0.011
0.009
0.016
O.OS4
0.093
-
0.002
0.006
waste
mg/1
weight
2900
1360
572
79
29
15
440
0.44
11
101
211
1.3
3.5
10.1
1.8
6.2
0.44
4.8
40
7.0
37
41
-
0.83
2.6
                Typical historical analysis, mean of many detemiinations.
                Quantitative analysis conducted by Industrial lab^iM Lories, rvean of two
                 analyses.
                Remainder of analyses conducted by Industrial Laboralories.  Qualitative
                 analyses by fluuiescence x-ray spec Irophotoine try. mean of four analyses.


                                        25

-------
     Sorghum  sudangrass  plots
llOOT/ha


[ 50T/ha|
llOOT/ha
[200T/ha


1 25T/hal
50T/ha

lOOT/ha

25T/ha

JOOT/ha

lOOT/ha

OT/ha

lOOT/ha

25T/ha

50T/ha

OT/ha

OT/hal

lOOT/ha

50T/ha

OT/ha

25T/ha
           Millet plots
I 50T/ha|  [l?5IZ.hal*i  OT/ha I* llOOT/ha
  QT/ha |  [sOT/hal  I 25T/ha I  tlOOT/ha
[JOOT/hal  [ 25T/ha|  I 50T/ha |  |lOOT/ha
        Filter  cake plots
 95T/ha 1   [ 45T/ha|  [ 87T/ha|  jlGU/ha
I 63T/hal   I 40T/hal  ll03T/ha
  27T/hal   l54T/hal  1 65T/ha
           Fallow plots
  25T/hal  llOPT/ha I  [l25T/h
          LzST/hal  I bOT/ha I   llOOT/ha
 *Infiltration  measurements  made on
  these plots.

 Fig.  8-Plot design layout with
   identification  and loadings
   (dry metric  tons per hectare)
   of each plot.
                  26

-------
It was expected that the moisture in  the sludge  would  soak  into  the  soil
causing the sludge to dry rapidly,  However,  it  took considerably  longer
than anticipated (about 4 to 6 weeks)  for the sludge to  dry (the plots with
the highest rates remaining moist longest).   In  the interim,  there were
distinct odor and fly problems which  led to  the  conclusion  that  high rates
of a mixture of anaerobically stabilized and waste  activated  sludge  could
not be applied to the soil  surface and allowed to dry.

When the sludge had dried,  it was mixed into the top 14.4  centimeters  by ro-
totilliny.  Soil samples were taken during the last week of June at  various
depths down to 0.76 meters.  A seedbed was prepared by tandem discing  and
the sorghum sudangrass and millet were planted on July 5,  1971  a date  that
was later than optimum.

A sprinkler irrigation system was installed  to supplement  rainfall.   Adequate
moisture was provided for seed germination and for  the prevention  of crusting.
Irrigation of approximately 5.6 centimeters  and  7.1 centimeters  were applied
on July 12-14 and July 21-23 periods,  respectively. These irrigations were
in addition to rainfall of approximately 3.81 centimeters  during the month of
July 1971.*

Germination and emergence counts on the sorghum  sudangrass and millet plots
were made on July 20, 1971.  The counts were made on three rows  each 8.6 me-
ters long.  These data showed poor germination but since it was  too  late  to
reseed and reseeding immediately would probably  not have been much more  suc-
cessful, it was decided that the project would be extended by planting winter
wheat in the fall.

The sorghum sudangrass was harvested  on September 3, 1971  in  spite of poor
germination and two hail storms.  The green and  dry weight  yields were deter-
mined.  A separate random sample was  taken from each plot, dried and finely
ground for a total N determination.  The millet was not harvested  because  of
severe hail damage.

Soil samples were taken at various depths down to 2.4  meters  on September  14
and 15, 1971 prior to tillage and seedbed preparation  for  the wheat crop.   The
soil samples were analyzed for N03-N, sodium bicarbonate extractable P,  ammoni-
um acetate extractable K, DTPA extractable Zn, Fe, Cu  and  Mn.

After harvest of the sorghum sudangrass plots, all  the plots  were  disced  and
a seedbed for winter wheat was prepared.  Wheat was planted on October 3  on
all 72 plots.  Wheat germination and  emergence counts  were made on October 15,
1971.

On November 30, 1971 a  limited number of plots were sampled to a soil depth  of
10.16 centimeters for bacterial  counts.  Numbers of total  aerobic, total  coli-
form, fecal coliform, and  fecal  streptococci bacteria  were determined by  dilu-
*The reported value is the average rainfall of the Denver WSO, Byers, and Ft.
 Lupton U.S. Weather Bureau stations for the month.


                                       27

-------
tion counts using a membrane filter technique  with the following  (Difco
Laboratories)  media for each group:

1.   Total  bacteria:  M-plate count broth.   17  gm in 1000  nil  of distilled
    H20.   Autoclave 15 minutes (15 Ibs.  pressure and 121°C).   Use  2.2  ml
    per absorbent pad.  Incubated 18-24  hours.

z-   Total  coliform:  M-Endo broth-MF.   48  gm in  1000 ml distilled  H^O  con-
    taining 21  ml ethanol.   Heat to boiling.  Cool.  2 ml  to each  sterile
    absorbent pad.  Incubate at 35°C for 24 hours.

3-   Fecal  coliform:  M-FC  broth.  3.7  gm in 1000 ml distilled H20.   Add  1
    ml  of~"I%~"Tosol"ic acid  in 0.2 N NaOH.   Heat to boiling.   Cool.   Use 2
    ml  per sterile absorbent pad.  (Cultures incubated by submerging in
    44,5°C water bath for  24 hours.)

4-   Tota]  streptococci: M-Enterococcus  Agar.   42 gm in 1000 ml  distilled
    H^O.   Heat to boiling  to dissolve  completely.   Disperse  into  petri
    dishes and allow to solidify.  Incubate for 48 hours  at  35-37°C.

During the fall of 1971 it was decided to  omit irrigation during  the spring
of 1972.   The wheat grew well  in the spring until  hot dry weather  threatened
to eliminate the wheat yields, whereupon the decision was made to  irrigate
to save the crop and obtain some yield data.  However, yields had  already
been severely depressed.

The wheat was harvested on July 14,  1972 and yields determined.   Some  subsam-
ples of the grain were separated and finely ground in a stainless  steel  Wiley
Mill for determinations of total N,  P, K,  Ca,  Mg,  Zn, Fe, Cu, Mn,  Pb,  B  and
Cd.  Total N was determined by macro-Kjeldahl  digestion using Kel  Pak  #2  as
a catalyst, and distillation into boric  acid.   Phosphorus determinations  were
made following nitric-perchloric digestion colorimetrically  using  ammonium
vanadate and ammonium molybdate.  Potassium, Ca, Mg, Zn,  Cu, Mn,  Cd and  Pb
were digested with nitric  perchloric acids, diluted and read on an atomic
absorption spectrophotometer.   Boron was determined by dry ashing  at 550°C
with ash dissolved in 0.1  N HC1 and color  development with circuminaxalic
acid.  The color intensity was read on a spectrophotometer.

Infiltration measurements  were made on four adjacent millet  plots  (see Fig.
8)  in late July of 1972.  These were chosen because they  are adjacent to  one
another,  thus,  eliminating as  much as  possible the effects of soil variations
in the measurements.  Six  unbuffered ring  infi 1 trometers  were installed  in
each plot and the cumulative infiltration  (up to 10.16 centimeters total  ap-
plication) was determined  as a function  of time.


Results and Discussion

After application of the sewage sludge on  the bordered plots, it took almost
six weeks for the sludge to dry at the soil surface.  This resulted in an ap-
preciable odor and fly problem until the drying was completed.  The conclusion
that this sludge  (a mixture of anaerobic and aerobically  digested sludges)


                                      28

-------
could not  be  judiciously applied to the soil  surface was reached,   The aero-
bically  digested waste activated sludge was not  sufficiently  stable to pre-
vent odor  and fly problems.

Germination and emergence  data  for the sorghum  sudangrass, millet,  and wheat
grown on the  field plots are  shown in Tables  10  and 11.  It is  apparent that
increasing amounts of sewage  sludge increased inhibition of germination and
emergence  of  sorghum sudangrass and millet.   However, when the  wheat was
planted  some  five months later, the factor  causing germination  and  emergence
inhibition had been eliminated  or dissipated, even at the higher rates of
sludge application.  There were no significant  differences between  the con-
trols and  sludge applied plots  on germination and emergence of  wheat.


Table 10-Germination and emergence counts on  July 20, 1971 for  three rows,
                             each 7.65 meters  long
                                          No. of plants (mean  of 4 reps ._]	
                                       No. of plants          Mo. of plants
         Sludge application rate               mean	             (mean)
metric tons/ha
0
2
4
8
10
S. sudangrass
132 a*
32 b
14 b
4 b
6 b
Millet
524 a
13 b
23 b
4 b
5 b
          Those means followed by the sane letter are not significantly different at
          theO.Ol level,  using Ouncan's Multiple Range Test.
Table  11-Wheat stand  counts  on October  15,  1971  for three  rows, each 1.83
                                   meters  long
                                    	No.  of plants (mean of 4 reps.]	
        Sludge application  rate         Previous fallow          Previous millet
            metric tons/ha                 plots                  plots

                 0                       545 a*                  464 a

                 2                       341  a                   465 a

                 4                       440 a                   427 a

                 8                       478 a                   377 a
                10                       398a                   485 a


         *Those means followed by the same letter  are not significantly different at
          the  0.05  level .
                                        29

-------
The harvested weights  of  the  sorghum  sudangrass  grown on the sludge treated
plots are shown  in Table  12.   The  extremely  low  values are due to poor ger-
mination and hail damage.   The yield  variations  are more likely to be a re-
sult of differences  in  germination and  emergence than directly due to the
sludge addition  on subsequent  plant growth.   From visual observations, the
individual plants grown in  the high sludge application plots were not smaller
than those of the check plots  or lower  application rates.


Table 12-Yield and nitrogen content of  sorghum sudangrass  as affected by
                          sludge application  rate.
         Application rate
          metric tons/ha
     Yield
dry weight (kg/ha)
0
25
50
100
125
410 a*
367 a
209 ab
101 b
60 b
1.08 a*
3.08 b
3.23 b
3.30 b
3.43 b
      * Mean value of 4 replications.   The mean values for %N  followed by the same
        letter are not significantly different at the .01 level.  The mean  values
        for dry matter yield followed  by the same letter are  not significantly dif-
        ferent at the .05  level.  Both sets of data were analyzed using the Duncan's
        Multiple Range Test.
The N contents of the harvested  sorghum  sudangrass  are shown in Table 12.
There was nearly a three-fold  increase in  the  nitrogen level of the sorghum
sudangrass grown on the sludge treated plots compared to that of the check
plots.  There were no significant differences  in  N  content of the plants
grown on any of the sludge  treated  plots even  though  the mean values increased
slightly with increasing sludge  applications.

The 1972 wheat yields on the three  sets  of plots  are  shown in Table 13.   On
the previously fallowed plots  there was  not a  significant difference in yield
between the check plots and any  of  the sludge  application rates except at 125
metric tons/ha.  This high  rate  was the  only one  at which wheat yields were
significantly lower than the check.  The wheat yield  picture was different on
the plots that were originally planted to  millet.   The mean yield values at
the 25 and 50 metric tons/ha ratios were significantly higher than the checks.
The yields on the 25 and 50 metric  tons/ha  plots  were also significantly great-
er than the 100 and 125 metric tons/ha plots.  The  wheat yield pattern on the
sorghum sudangrass plots is similar to that of the  millet plots, but there
were no significant differences; thus, the  application of sewage sludge (125
metric tons/ha fallow plots) significantly  decreased  the yield of wheat com-

                                      30

-------
pared to the check, whereas in two instances (25 and 50 metric tons/ha  - mil
let plots), sludge application appreciably increased wheat yields.

Table 13-Effect of sewage sludge addition to Truckton loamy sand on winter
                             wheat yields, 1972
                                      Dry matter yield  (kg/ha)
     Application rate      	Treatment in  1971    	
     metric tons/ha       Mi 11et      Sorghum sudangrass       fallow      means
0
25
50
100
125
777 a*
1220 b
1184 b
688 a
320 a
439 a
973 a
902 a
558 a
619 a
826 a
600 ab
428 ab
608 ab
254 b
681
931
838
618
398
   * Mean values of 4 replications.  Values followed by the same letter are not sig-
     nificantly different at the 0.05 level using Duncan's Multiple  Range Test.
Chemical analyses of wheat grain grown on the 0, 25 and  100  metric  tons/ha
treated plots are shown in Table 14.  The mean values  for  N,  K,  Ca,  Zn,  and
Mn increased significantly in the wheat grown on the 25  metric  tons/ha plots
compared to the checks.  The additional increase at the  100  metric  ton/ha
compared to the 25 metric ton/ha rate was not as great.  There  were  no sig-
nificant differences between any of the application rates  for P,  Mg,  Fe,  Pb,
and Cd.  There was a significant difference  in Cu  content  of the  wheat be-
tween the 25 and the 100 metric ton/ha plots.  However,  in no case  was the
content of any of the elements analyzed high enough to be  outside the nor-
mal range of concentrations found in plant materials.

It should be pointed out that when these plots were prepared the  land was
leveled to facilitate the application of liquid sludge to  level  bermed plots.
During the operation much of the topsoil was redistributed,  thus, some plots
contained little topsoil while others had topsoil  added  to them.   This pro-
bably resulted in considerable variability within  the  plots.  This  variabi-
lity in soil most likely contributed to the  variability  in the  data  obtained,
decreasing or obscuring statistical significance.

Since there were no duplicates on the filter cake  plots, a different type of
statistical analysis had to be run.  A polynomial  regression analysis indi-
cated a slight decrease in wheat yield with  increased  filter cake addition
above 454 kilograms per plot, but the differences  are  not  significant (see
Fig. 9).  It should be noted that the checks averaged  550-789 kilograms  per
hectare, which is considerably lower than any of the filter  cake  plot yields.

An 8.1 hectare dryland area in a typical wheat  field on  the  Danford-Champlin
                                      31

-------
Table 14-Total  elemental  composition  of wheat grain as influenced by rate of
 Metro sewage sludge addition.
Sludge application rates
dry metric tons/ha
Element
°i N
la IN
"/ P
lo "
% K
% Ca
% Mg
ppm Zn
ppm Fe
ppm Cu
ppm Mn
ppm Pb
ppm B
ppm Cd
0
2.06 a*
0.41 a
0.41 a
0.046 a
0.143 a
34.8 a
36.3 a
3.50 a
37.2 a
0.15 a
0.90 a
0.07 a
25
2.89 b
0.51 a
0.49 b
0.073 b
0.149 a
52.5 b
45.9 a
4.46 a
77.0 b
0.14 a
1.31 ab
0.16 a
100
3.10 b
0.45 a
0.52 b
0.076 b
0.156 a
54.2 b
46.5 a
5.96 b
83.6 b
0.08 a
1.46 b
0.19 a
   * The mean values  in  each  row  followed  by  the  same  letter are  not
      significantly different at  the  0.05  level using  Duncan's Multiple
      Range Test.
           2240


Dry Grain  1680
Yield (Kg/ha)

           1120


            560
                                (33-2)
                                       (32-2)
                                  (3?-2)      (32-1)     (32-3)   (34-3)
                                                         •
                                                                 •
                                                                (£-3)
                   (Check)
                                         56 T/ha
                                                                   112 T/ha
                                                                     i
                      227   454   681   908  1135  1362  1589   1816
                                      Filter Cake Addition (Kg/plot)
    Fig.  9-1972 wheat yield on filter cake plots.
                                     32

-------
Farms at Watkins  was treated with about 22,4  metric tons per hectare of fil-
ter cake during the summer of 1971.   The cake was  incorporated into the soil
by tillage shortly after application.   Winter wheat was planted and sampled
on July 14,  1972.  Five strips 1.2 x lb,2 meters were taken at random in
the filter cake treated area and a similar sampling from the nonfilter cake
treated area.   The wheat yield data are shown in Table 15.   There were no
appreciable differences in the mean values of the  filter cake treated and
the nontreated strips.

Table 15-Wheat yields from applications of 22.4 metric tons per hectare of
                             filter cake sludge
                           Dry matter yield (kg/ha)
                 Sludge strips                 Non-sludge strips





Mean
1602.0
1622.5
1613.4
3351.3
2582.0
2042.2
2532.5
2218.16
1720.32
1645.1
1783.8
Mean 1979.9
The  field was harvested shortly after, and by a subjective evaluation of Mr.
Jack  Danford the yields were not greatly different on the two areas of  the
field.  The filter cake had no apparent effect on dryland wheat yield.

There were no appreciable differences between the variation of the elements
with  soil depth as influenced by cropping situation.  Therefore,  results are
discussed for all three cropping situations.  Data which differ significantly
from  the general trends were eliminated for  the generalized figures included
in  the  text.

The  first set of soil  samples taken  shortly  after sludge incorporation  showed
the  normal pH of the  topsoil to be about 6.7 and increasing to about  pH 7.0
at  a  depth of 0.76 meters, which is  typical  of soils  in  this area (see  Fig.  10).
After sludge incorporation the soil  pH  increased; however, after  incubation
through the summer months the pH of  the surface soils  (0 to 15 centimeters)
decreased compared to the control  plots.

Salt concentrations  as measured by electrical conductivity show  that  the  salt
concentrations  increased with increasing sludge additions  (see  Fig. 11).  Sludge
additions between 25  and 50 metric tons/ha  did not  cause a salt  problem.   Ap-
plication rates  greater than this  caused the conductivity  to  rise to  between 3
and 4 mmho/cni which  could possibly be  detrimental to  sensitive  crops.
                                       33

-------
                Sampling Time  I, Spring   1971
                          Soil  pH
                     Sampling Time 2, Fall  1971
                            Soil  pH
                          OUII  |/n                                       
-------
The general change in organic matter content of the soil is shown in Fig.  12,
The higher the sludge application  rate the higher the organic matter content
of the soil.  Fig. 12 demonstrates  that there was some organic matter decom-
position during the summer  months.   Below the 0.3 meter depth there were  no
measurable differences  in the organic matter content of the plots.
                 Sampling Time I, Spring 1971
                   Organic Matter (%)
                1.0      2.O      3.0
 Soil
 Depth
 (m)
 .30


 .61-


 .91


1.22-


1.52-


1.83-


2.13-


2.44
                                                  Sampling Time 2, Foil 1971
                                                     Organic Matter (%)

                                                  1.0      2.0      3.0
          :heck
                        100-125 T/ho

                -25-50 T/ho
                                                 Checl
      .30


      .61-


      .91
Soil
Depth  1.22
(m)

     1.52
                                              1.83-
                                              2.13


                                              2.44
       100-125 T/ho

25-50 T/ha
Fig. 12-Organic matter content of soil with  various  rates  of sewage sludge
 additions.

Nitrate-nitrogen  content of the surface soil  samples  were 2, 4 and 10 times
higher than the control  plots for the 25, 50  and  100  metric ton/ha sludge ap-
plication rates,  respectively (see Fig.13).   The  second sampling shows that
the  N03-N content had increased markedly in the surface soils and had leached
to  a depth of about 2 meters.

Available P remained for the most part in the surface soils with some move-
ment to the 0.4 meter depth (see Fig.14).   The bulge  at the 1.5 meter depth
is  likely an analytical  error rather than any movement to this depth.  The
surface soil samples that have had sludge applications all  show high levels
of  available P, but it is doubtful that this  could  be considered detrimental
to  plant growth.

The check plots contained about 120 to 140  ppm of extractable K in the sur-
face soils at the time of the first sampling  (see Fig. 15).  The intermediate
sludge application rates (25 to 50 metric tons/ha)  caused the available  K le-
vel  to increase to over 200 ppm.  Heavy rates (100  to 125 metric tons/ha)
caused the K content to rise to over 350 ppm. After the summer period,  the
K distribution had not changed appreciably  in the surface soils.  Sludge ad-
ditions increased the K level to the 0.45 meter  depth; possibly indicating
some downward movement of K.
                                       35

-------
           0
                 Sompling  Time  I, Spring 1971
                     NO-jN  Content (ppm)
                   20        40       60
Soil
Depth
 (m)
 .30

 .61

 .91

1.22

1.52

1.83-

2.13

2.44
            :heck
                                        80
                            Sampling  Time 2, Fall 1971
                                NO,  Content (ppm)
                              20       40        60
                     100-125 T/ho

                       T/ha
                                                                                       T/ho
                                                      2.44)
 Fig.  13-N03-F
          of  soil with  various  rates of  sewage  sludge additions
          o
       .30

       .61 -

       .91
Soil
Depth  |.22
(m)
      1.52-

      1.83-

      2.13 •

      2.44-
          Check
                 Sampling Time I, Spring 1971
                      P Content (ppm)
           IOO
                           300
 300
—i—
                                       400
Sampling Time 2, Fall 1971
     P  Content (ppm)
 100      200      3OO
                '25-50 T/ha
                                                    Check
                                  IOO-125 T/ha
400
                                  25-50 T/ha_
                                           100-125 T/ha
Fig.  14-Available P  content of  soil  with  various rates of  sewage sludge
 additions.
                                               36

-------
        o-
Soil
Depth
 (m)
 .30

 .61

 .91

1.22-


1.52-


1.83-

2.13-

2.44
                 Sompling  Time  I, Spring 1971
                       K  Content (ppm)
                  100      200       300
                                                         Sompling  Time  2, Foil 1971
                                                             K Content  (ppm)
                                       400
                 100
              Check
                                    100-125 T/ha

                          -25-50 T/ho
Soil
Depth
 (m)
 .30

 .6H

 .91

1.22-


1.52-


1.83-

2.13-

2.44-
                     200
                    	i—
 300
—i—
400
                                                             Check
                                 100-125 T/ho

                          -25-50 T/ho
Fig.  15-Available K  content of  soil with various  rates  of sewage  sludge
  additions.
                  Sompling  Time I, Spring 1971
                        Zn Content (ppm)
                    10       20       30
                                       40
                                                          Sompling Time 2, Foil  1971
                                                               Zn  Content (ppm)
                                                         10        20       30
                                          40
0-
.30
.61-
son -9I
Depth
/ \ ' 22
(m)
1.52
1.83
2.13
2.44-
	 1 	 1 	 1 — . 	 •» V-
Xf^ " IOO -125 T/ho .30-
^-25-50 T/ha
.61 •
son -91'
Depth
, . L22
(m)
1.52.
1.83
2.13
2.44
Check 	 25-50 T/hg 	 •
X^--" 100-125 T/ha




 Fig.  16-DTPA extractable Zn  content of  soil with various  rates  of
  sewage sludge additions.
                                               37

-------
                   Sampling  Time  I, Spring 1971
                       Fe Content (ppm)
                    10       20        30       40
                                                          Sampling Time 2, Fall  1971
                                                             Fe  Content (ppm)
                                                         10        20       30
                                             40
         0
        .30

        .61

        .91
Soil
Depth   I • 22
 (m)
       1.52-

       1.83-

       2.13

       2.44
                                                        0
             Check
                             100-125 T/ha
                                             .30

                                             .61 •

                                             .91 •
                                      Soil
                                      Depth   1-22
                                      (m)
                                             1.52-

                                             1.83-

                                             2.13

                                             2.44-J
                                                              Check
                                  45 - 55 T/ ho
                              -22  T/ha
  Fig.  17-DTPA extractable Fe  content of  soil  with  various  rates of  sewage
   sludge additions.
                   Sompling Time I, Spring  1971
                       Cu Content (ppm)
                      246
                                                          Sompling Time  2,  Fall 1971
                                                              Cu Content (ppm)
                                                            246
  Soil
  Depth
   (m)
  0

 .30

 .61

 .91

1.22-

1.52

1.83-

2.13

2.44
                                100-125 T/ho
       .30

       .61

       .91
Soil
Depth  >• 22
 (m)
      l.52^

      1.83

      2.13

      2.44J
                                                                                 100-125 T/ho
                                                                   25-50 T/ha
  Fig.  18-DTPA extractable Cu  content of soil  with  various rates of  sewage
   sludge additions.
                                                38

-------
            Sompling Time  I, Spring 1971
                Mn Content (ppm)
Sompling Time 2, Foil 1971
    Mn Content  (ppm)
0 20 40 60 80 0
. i J f\ _
o-
.30-
.61 -
Soil "9I
Depth
(m)
1.52
1.83-
2.13
2.44
heckl / ^^^ 100-125 T/ho
k^W5-50T/ho 3°
H .61 '
_ . .91 '
Soil
(m) L22
1.52-
1.83
2.13
2.44
20 40 60 80
, i • '
Check / ^^-^^-^"^00-125 T/ho
/yX^ \-25- 50 T/ho
f






Fig. 19-DTPA estractable  Mn  content  of  soil  with  various  rates of sewage
 sludge additions.


Bacterial  counts were made on surface soil  samples taken on November 30, 1971
after harvesting of the crops (see Table 16).   There was an appreciable in-
crease in  total aerobic bacteria (probably reflects the increased food source
of sludge  organic matter), total coliform bacteria and fecal streptococci.
Fecal coliform bacteria were not increased by sludge additions to the soil.
An estimate of the number of fecal coliform bacteria in the original soil-
sludge mixture would be on the order of 1 x 10&; thus, the die off rate for
fecal coliform during the summer months would be somewhere around a thousand
to ten thousand fold.

Infiltration determinations were made on four adjacent millet plots (see Fig.
8) in late July of 1972.  Twelve determinations made on the control plots
were considered checks and those on  the 125 metric ton/ha of sludge applied
plots were considered as  the treated plots.  The time to infiltrate 1.27 cen-
timeters,  2.54 centimeters, 5.08 centimeters and 10.16 centimeters of water
were taken as  the dependent variables.   In  addition to the amount of sludge
applied, the moisture content to the 91.44  centimeter depth and the center of
gravity of the moisture  to the  91.44 centimeter  depth were also considered as
factors affecting infiltration.  The infiltration  results are displayed in
Fig. 17 and the average  values  for  the  infiltrated depths are shown in Table
17.

The  scatter in  Fig.  20 is typical of measurements  made with cylinder^infiltro-
meters.  This  is due in  large measure  to the  small area  samples  (45.22  centi-
meter diameter) and  the  corresponding  large edge effects around  the cylinder.
These are due  primarily  to  the  shattering  of the soil  when  the  infiltrometer
is  driven into the ground

                                       39

-------
Table 16-Bacterial counts of soil samples taken from fields (fallow and
              sorghum sudangrass) treated with sewage sludge
Sludge applied Soil depth
metric tons/ha (cm)
Fallow
0
125
Sorghum
0
0
0
25
25
25
125
125
125

0 -
0 -
sudangrass
0 -
3.2 -
6.3 -
0 -
3.2 -
6.3 -
0 -
3.2 -
6.3 -

6.3
6.3

3.2
6.3
10.1
3.2
6.3
10.1
3.2
6.3
10.1
Total
aerobic
bacteria

3.3 x
24 x

4.0 x
5.8 x
5.6 x
13 x
12 x
16 x
14 x
17 x
4 x

IO6
IO6

IO6
IO6
IO6
IO6
IO6
IO6
IO6
IO6
IO6
Total
col i form
bacteria

2.2 x
6.9 x

1.4 x
.35 x
.24 x
.45 x
2.8 x
4.5 x
30 x
5.3 x
8.5 x

103
IO3

IO3
IO3
IO3
IO3
ioa
IO3
103
103
IO3
Fecal
col i form
bacteria

<1 x 103
<1 x IO3

<1 x IO2
<1 x IO2
<1 x IO2
<1 x IO2
<1 x IO2
<1 x IO2
<1 x IO2
<1 x IO2
<1 x IO2
Fecal
streptococci

< 1 x
<3.2 x

< 1 x
V 1 X
N 1 X
13 x
28 x
89 x
.8 x
6.3 x
6.9 x

IO2
IO2

IO2
IO2
IO2
IO2
IO2
IO2
IO2
IO2
IO2
Table 17-Average values  for infiltration  rates  on  sludge  treated soils
Infiltrated depth of
water (cm)

1.27
2.54
5.08
10.16
Time to infiltrate
on control plots
f
- min
1.48
4.66
14.62
46.02
Time to infiltrate
on sludge plots

0.57
2.69
12.76
60.57
                                    40

-------
                                Infiltration  (Acre  Feet/Acre)
          10
Time, min.
          100
                              °
                               0
                     o
             0.01
                                  o
                                      O
                                       o
S   8*  *•
o 0 &>o .
   OD
                        •  Sludge plots

                        o Non-sludge plots
                                                        •  •

                     o
                     o
                                                                 o
                                                     J	L
0.1
1.0
       Fig.  20-Infiltration of water  into  sludge  treated and non-sludge treated
        soils.
                                     41

-------
From the standpoint of modeling it was found that the effect of  sludge  appli-
cation is largely overshadowed  by other variables, except in the case of the
2 inch water application.   The  most significant variable found in  modeling
each of the water applications  is shown in Table 18.

Table 18-Significant  variables  found in modeling water applications  of  1.27,
                      2.54,  5.03 and 10.16 centimeters.
         Depth of infiltrated water
                 (inches)
    Most influential  variables measured
                  1/2
Moisture content, center of gravity of
moisture content

Moisture content, center of gravity of
moisture content, product of moisture
content and center of gravity of moisture
content

Moisture content, center of gravity of
moisture content, sludge or sludge alone

None of variables selected were signifi-
cant
The conclusion  to  be  reached from the infiltration studies  is  that sludge did
not appear to offer any  adverse effect on the infiltration  of  water into the
soil when measured after cropping.


Summary and Conclusions

Germination and emergence of the sorghum sudangrass and millet were poor on
all plots where sludge had been applied.  Subsequent poor growth  and two hail
storms prevented the  obtaining of useful yield data.  The winter  wheat exhibi-
ted no germination or emergence inhibition.   Wheat yield data  showed a ten-
dency toward increased growth on the 25 and 50 metric ton/ha sludge plots, but
these increases were  not statistically significant except for  the original
millet plots.  When the  plots were  prepared the land was leveled  to ensure
level plots for the liquid sludge applications.  This leveling caused some of
the sandy topsoil  to  be  removed from some areas and added to others.  This re-
sulted in considerable variability  within the plots.  This  variability in soil
most likely contributed  to the variability in the data obtained,  decreasing
or obscuring statistical  significance.

With increasing sludge applications there was an increase in salts, N03-N, P,
K, Cu, Zn, Mn and  Fe  in  the surface soil.  Below the top 30 centimeters of
soil only NOs-N accumulated in appreciable quantities above the control levels,
There was a slight indication of increased concentrations of P and K at 30 to
46 centimeter depths.

Microbial counts showed  that the sludge plots had an appreciable  increase in
                                       42

-------
total aerobic, total coliform and fecal streptococci bacteria,  while the fe-
cal coliform bacteria were  not greater in the sludge plots  than in the con-
trol plots.

Infiltration measurements  indicated that infiltration was not significantly
increased or decreased  due  to sludge application one year after application.


THE EFFECT OF METRO SLUDGE  ON GERMINATION AND PLANT GROWTH  OF THREE
 CROPS IN A GREENHOUSE  STUDY

The studies conducted at the Watkins research plots demonstrated germination
inhibition in sorghum sudangrass and millet when the seed was planted soon
after liquid sludge incorporation into the soil.   To investigate the effect
of liquid sludge  and  filter cake on the rate of germination and subsequent
early plant growth, a greenhouse study was conducted at the Elliot carnation
greenhouse adjacent to  the Metro plant.


Maten' a1s and Methods

A bulk sample of  topsoil from the experimental area at  Watkins, Colorado was
obtained for r.iixiny witii cue sewage sludge and filter  cake  for this study.

Samples of typically  produced sewage sludge and filter  cake were dried  and
prepared for bulk mixing with the soil as shown in Table 19.


     Table 19-Rate of  sludge applications to Truckton  sandy loam soil
Treatment no.
1
2
3
4
5
6
7
8
X
Sludge addition
0
' 1.0
2.0
4.8
2.0
4.8
9.1
1.0
Equivalent dry rStes
in metric tons/ha
0
22.4
44.8
106.7
44.8
106.7
203.6
22.4
Type of Sludge3

filter cakeb)
filter cake
filter cake
driedc^
dried
dried
liquidd)
      a)  Sludge was SOX anaerobically digested primary sludge and 50% aerobically di-
         gested waste activated sludge.
      b)  Filter cake sludge added to soil at 17% dry weight solids.
         Dried sludge was air dried filter cake added to soil.
         Liquid sludge added to soil at 52 dry weight solids.
                                       43

-------
 The various soil treatments were added to plastic lined cardboard cartons
 (1.8 liters) at the rate of 2.17 kilograms per pot.   No fertilizer additions
 were made; thus, the only nutrients available were from the sludge additions
 and the native soil (see Table 9).   Water was added  to  field capacity.

 The pots of treated soil  were  allowed  to  incubate  for 0.5,  1, 3 and 6 months
 prior to seeding with  wheat, sorghum sudangrass hybrid, or  corn.  After the
 selected incubation periods, 36  wheat, 36  sorghum sudangrass, or 16 corn
 seeds were  planted  by  removing the proper depth of soil  from the surface of
 the  incubated pots.  Seeds were  distributed evenly and covered with soil.
 The  pots were watered as needed to ensure adequate moisture  for germination
 and  growth.

 Counts of the number of emerging  seedlings and average plant height were made
 after 4 weeks.   The pots were then thinned to  three corn,  four wheat,  and
 four sorghum sudangrass plants  and allowed to  grow for the time  intervals spe-
 cified in Table 20.   The plants were then  harvested,  dried at 60°C and weighed.


 Table 20-Soil  incubation periods  and corresponding planting, thinning  and
                               harvest  data
Incubation
period
2 weeks
1 month
3 months
6 months
Date
seeded
4/5
4/19
6/21
9/27
Date
thinned
5/3
5/21
7/12
10/25
Date
harvested
6/20
6/20
9/13
12/12
Growth period
in days
76
62
84
76
Results and_Discussjoii

The number of seeds that germinated and  emerged  after 1,  3 and 6 month pre-
incubation periods are noted in Tables  21a,  21b  and 21c,  respectively.  Ger-
mination data for the two week incubation  period are not  included because the
seeds and emerging seedlings were consumed by mice.  When this problem became
evident screens were placed over the pots;  thus, only the data from the one
month and longer incubation periods are  shown here.

Wheat was the least detrimentally affected by sludge additions, with germina-
tion essentially complete after two weeks.   Sorghum sudangrass was the most
adversely affected of the crops grown.   Even the lowest sludge application
had an adverse effect with the high rate of wet  filter cake reducing germin-
ation rates by about two-thirds.   Incubation periods longer than one month
had some beneficial effect on sorghum sudangrass,  but little effect on wheat
and corn.  This evidence would tend to  indicate  that at least part of the

                                      44

-------
Table 21a-The  effect of sewage  sludge on germination and emergence of seeds of
              three crops.   Seeds planted one  month after the  treatments were
                               mixed with the  soil.
Treatment no.
Wheat
1
2
3
4
5
6
7
6
Sorghum sudangrass
1
2
3
4
5
6
7
8
Corn
1
2
3
4
5
6
7
8

/

20
10
1
0
4
0
0
23

0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0
Days
H
Number of

31
32
24
11
32
15
3
34

21
9
9
2
7
0
0
14

9
11
3
2
1
1
0
16
after
15
seeds

34
35
29
28
34
32
16
34

29
21
10
4
17
4
0
21

16
16
11
6
8
4
4
16
planting*
20
germinated

33
33
28
31
33
34
22
34

30
22
12
5
18
8
0
22

16
16
14
6
16
10
5
16

M

33
34
29
34
34
35
26
34

32
22
12
5
18
9
0
18

16
16
16
12
16
12
5
16
        Counts were made on other days;  however, the five reported in this table give
        the essential  trends in  germination and emergence.
                                         45

-------
Table  21b-Seeds planted three  months after the treatments were  mixed with soil
Days after planting*
Treatment no.
Wheat
1
2
3
4
5
6
7
8
Sorghum sudangrass
1
2
3
4
5
6
7
8
Corn
1
2
3
4
5
6
7
8
4_

12
5
4
1
2
4
3
10

0
0
1
0
0
0
0
0

0
0
0
0
1
0
0
0
i Z 19. 11 2T
Number of seeds germinated

29
20
14
4
14
17
5
26

2
0
3
0
2
0
0
2

3
6
2
0
3
1
0
2

32
31
25
9
25
31
8
31

26
8
13
0
4
8
0
17

16
5
10
0
9
8
2
10

34
34
31
15
32
34
17
36

31
14
16
4
16
18
4
21

16
16
16
7
16
15
10
16

34
34
32
19
32
34
26
36

31
16
18
5
19
21
6
24

16
16
16
7
16
15
12
16

34
34
32
22
32
34
33
36

31
16
18
5
20
21
7
25

16
16
16
9
16
15
12
16
       * Counts were made  on other days; however,  the six reported  in this table  give
         the essential  trends in germination and emergence.
                                         46

-------
Table  21c-Seeds  planted six  months after the treatments were  mixed with  soil
Days after planting*
Treatment no.
Wheat
1
2
3
4
5
6
7
8
Sorghum sudangrass
1
2
3
4
5
6
7
8
Corn
1
2
3
4
5
6
7
8
5.

2
0
0
0
6
1
0
7

7
8
0
0
0
2
0
3
1
0
0
0
0
0
0
1
1 9 14 16
Number oT seeds germinated

11
24
2
2
19
9
4
22

16
8
0
0
4
8
2
11
6
5
0
0
9
3
2
6

17
29
5
3
25
15
12
29

20
11
2
0
8
12
8
15
10
8
1
1
12
6
8
10

20
32
15
4
31
31
16
32

22
12
4
0
13
15
13
18
16
15
4
4
16
13
10
16

22
32
15
6
31
31
16
32

23
12
4
0
14
16
13
18
16
16
5
5
16
14
13
16
22.

25
32
15
7
33
33
23
33

23
12
5
1
15
16
14
18
16
16
6
6
16
15
14
16
       * Counts were made on other days; however,  the six reported  in this table  give
         the  essential  trends in germination and emergence.
                                         47

-------
inhibition of germination was due to some volatile component in  the  sludge,
perhaps ammonia (NH3J.  The wet sludge cake was the most inhibitive  at  one
month, but this inhibitive effect was decreased either by drying prior  to
mixing with the soil, or after incubating in the soil  for three  to six  months.
Corn was intermediate in tolerance to germination inhibition,  and was only
adversely affected at the high rates of sludge addition.

Variations in germination counts within the controls and treatments  were pro-
bably due to the fact that temperature within the greenhouse varied  signifi-
cantly and were generally below the optimum germination temperature  for corn
and sorghum sudangrass.   The experiment was carried out in a carnation  green-
house where temperatures were regulated near ]8°C.

Data showing early growth (centimeters of height) of seedlings after germina-
tion and emergence are shown in Table 22.   Examination of these  data indicates
that the early growth rates were not consistently increased with increases  in
pre-incubation periods.   As was generally true of the  germination data,  the
one month and six month plant heights were often lower uian the  two  week and
three month plant heights.  Evidently, the greenhouse  environment played a  sig-
nificant role in the rate of growth of the seeulings.   However,  it can  be  seen
that the height of the crops was appreciably influenced by the rate  of  sludge
addition, which is most likely a reflection of rate of germination.

Pots were thinned to 3 or 4 average sized plants after approximately 4  weeks
growth and allowed to grow another 2 to 3 months.  The data showing  the oven-
dried weights of the harvested plant material are shown in Table 23. Since
the growth periods were not the same for all four of the incubation  period
treatments (see Table 20 for growth periods) the yield data are  not  comparable
except for the 76 day growing period for the plants in the 2 week and 6 month
incubation periods.   It appears that incubation of the soil-sludge mixtures
for more than 2 weeks for wheat was not helpful.  Corn and sorghum sudangrass
showed increased yields with an incubation period of 3 months, however,  there
were no further increases in yield at 6 months.  In fact, if the 6 month yield
is compared with the 2 week yield for sorghum sudangrass and corn, both having
growth periods of 72 days, it appears doubtful that there was  an appreciable
growth response for  incubation periods longer than  2 weeks.
Conclusions
Treatments 1  and 8 had the best effects on the three biological  parameters
measured in this study with little difference between them.   It  is  apparent
that treatments 4 and 7 were the poorest.   Thus,  the wet  sludge  filter cake
had the largest adverse effects on plant growth when compared on an equivalent
weight basis  to the dried sludge.

Sorghum sudangrass was the most inhibited by sludge additions, and  was affected
to some extent by all sludge treatments.   Corn was  intermediate  in  tolerance,
and wheat was the least affected by sludge additions.   There  appeared to be no
inhibition of germination and emergence of wheat  and corn after  an  incubation
period of 1 month, except for treatment 7 which continued to  have inhibitory
effects through 6 months of soil incubation.


                                      48

-------
Table 22-The effect  of sewage sludge on  early  growth (two weeks after planting)
                      of three crops grown  in a greenhouse
Treatment no.
Wheat
'I
2
3
4
5
6
7
8
Sorghum sudangrass
1
2
3
4
5
6
7
8
Corn
1
2
3
4
5
6
7
8

2 weeks
Seed!
8.0*
7.3
7.1
6.9
3.8
2.4
0.6
8.0

1.2
2.8
1.3
1.5
0.3
0.2
**
1.4
3.0
4.3
2.2
4.5
0.7
0.6
0.1
2.2
Incubation
1 month 3
period
months

6 months
ing height in centimeters
10.0
7.8
5.0
3.4
6.2
2.3
0.6
10.0

1.5
1.0
1.0
0.2
0.3
0.1
*+
1.5
4.2
3.2
1.5
0.5
0.6
0.2
-
4.6
16.0
12.6
9.0
9.6
7.4
7.0
4.6
9.6

5.0
1.7
2.3
1.0
1.8
1.8
0.4
2.1
9.4
7.8
6.4
3.0
0.8
5.3
2.7
8.6
10.0
10.1
6.6
5.0
7.0
8.0
8.0
11.2

5.1
5.7
2.8
3.2
7.0
4.0
4.6
7.4
4.4
3.5
1.3
0.7
2.5
2.5
2.1
6.0
      *  Data  are mean values  of 5 replicates.
      ** No germination.
                                         49

-------
Table 23-The effect of sewage  sludge  on  oven  dry weight of three crops grown
                      in a  greenhouse for  2  to 3 months
Treatment no.
Wheat
1
2
3
4
5
6
7
8
Sorghum sudangrass
1
2
3
4
5
6
7
8
Corn
1
2
3
4
5
6
7
8

2 weeks

1.41
3.36
2.36
2.22
2.35
2.49
0.67
3.38

0.29
0.21
0.12
0.07
0.06
0.12
0.06
2.91
0.93
2.21
0.37
0.57
0.32
0.07
0.64
2.81
Incubation period
1 month 3 months
Yield
0.47
1.68
0.55
0.17
0.89
0.13
0.14
1.12

1.43
0.92
0.39
0.06
0.21
0.05
*
1.06
1.40
1.29
0.75
0.80
0.71
0.40
0.12
2.00
(grams/pot)
0.67
0.99
2.57
1.75
1.30
0.99
1.15
1.69

0.79
1.31
1.78
0.71
1.50
1.58
0.79
2.30
2.12.
2.48
2.14
1.53
2.58
1.95
0.82
3.16
6 months

1.46
0.90
0.81
0.93
0.86
0.70
0.32
1.05

1.22
0.31
0.58
0.14
0.31
0.40
0.06
0.95
2.35
2.16
0.69
0.57
1.25
0.55
*
*
2.46
     * No plants harvested.
                                      50

-------
The dried sludge had less inhibition  than  equivalent weights of wet  filter
cake on emergence and subsequent early  plant  growth.

Ambient temperatures of the greenhouse  used for  this study  were too  low  for
adequate germination and growth of sorghum sudangrass,  plus the loss  of  seeds
and some plants to hungry mice made interpretation  of  these data  difficult.
It appears, however, that the effects of sewage  sludge  additions  were more in-
hibitive to sorghum sudangrass germination and emergence  than  to  corn or wheat.


SLUDGE AIR DRYING PROJECT

If liquid sludge is transported from the treatment  plant  by conventional truck
transport, energy requirements are extremely high and  the cost of haul  becomes
rapidly prohibitive with increasing distances from  the treatment  plant.   While
removal of some of this water by vacuum filtration  reduces  hauling costs,  me
total costs are still extremely high.

Metro has been investigating pipeline transport of  liquid anaerobically di-
gested sewage sludge to a remote area where the sludge could be air dried and
subsequently utilized as an agricultural product.  This metnod would not only
avoid expensive haul and vacuum filtration costs, but  would also  provide a val-
uable agricultural product.

A research project examined the possibilities of drying liquid sludge in
shallow, earthen drying basins.  Parameters measured were water  loss through
soil percolation and/or evaporation, nitrogen losses and the development of
odors or undesirable vectors, i.e.  flies or rodents.


Materials and Methods

Five drying basins were built at the CSU Agricultural  Experiment Farm at Fort
Collins.  The basin  dimensions were 7.6 centimeters x 9.14 meters x  1.2 meters
in  depth.  Anaerobically digested  liquid sludge  (approximately 5%) from the
East Drake Wastewater Treatment Plant in Fort Collins was  added  to the  basins
on  August  7, 1973 to depths of  25.4, 50.8, 76.2  and 101.6  centimeters (Table
24).   The  basins did not have underdrains, and basin E was lined with plastic
to  prevent water losses due to  percolation.  Basin G was filled with 101.6
centimeters of  anaerobically  digested liquid sludge on January 16, 1974 to de-
termine  drying  rates and nitrogen  losses during  winter months.

Water  loss was  determined  daily by measuring the level of  the liquid sludge in
the drying basins.   Percent TS  were  determined weekly.   Determinations  of TKN,
NH4-N  and  N03-N were made  weekly.  Zinc,  Cu, Mn  and Fe are reported  as  DTPA
extractable metals.  Available  P  was determined  by extraction with ascorbic
acid.   Potassium was analyzed by  extracting  with normal  NH/jOAC.


 Results  and  Discussion

 Basin  A to which 25.4  centimeters of sludge were applied,  dried  from about  5«


                                       51

-------
TS to about 50% to 60% solids in a 1 month period (Table 25).  Basin B to
which 50,8 centimeters of sludge were applied, dried to 40% TS in a 4 month
period.  None of the other basins dried during the duration of the experi-
ment (10 months).   It is interesting to compare basin B (unlined) with ba-
sin E (lined).  Both basins received 50.8 centimeters of sludge, however,
the latter basin showed more dilute solids concentration in January 1974
than when it was originally loaded in August 1973.  This demonstrates that
most of the water loss was due to percolation into the soil rather than
evaporative losses, and that during the winter months precipitation exceed-
ed evaporative losses.

                   Table 24-Initial depth of liquid sludge

                Basin                    Liquid sludge  depth (cm)
A
B
C
D
E*
G
25.4
50.8
76.2
101.6
50.8
101.6
              *
                from percolation.
Table 25-Change in percent total solids content of drying basin with  time


                                            Sampling Date
                                        8773	    	T77T
                Basin                      % Total sol ids
A
B
C
D
E
4.6
4.6
4.2
4.2
4.2
61.7
40.3
13.9
7.5
3.3
The Fort Collins Agricultural Experiment Station has a permanent meterological
station where pan evaporation and precipitation are accurately measured.   Data
from this station indicated  that:

   A)  Net evaporation  (evaporation minus precipitation) occurred  during  the
       months of June through December.
                                      52

-------
   B)  Negative evaporation (excess of precipitation over evaporation)
       occurred during January through May.

   C)  Total precipitation (rain and snowfall) averaged 2.8 centimeters
       per month for a total of 34.0 centimeters between October 1972 and
       September 1973,

   D)  Gross evaporation totaled 92.7 centimeters.

   E)  Net evaporation totaled 08.7 centimeters.

   F)  Precipitation during the 7  driest  months  (June  through  December)  to-
       taled 20.3  centimeters.

   G)  Gross evaporation during the 7 driest  months  (June through December)
       totaled 58.4 centimeters.

   H)  Net evaporation during  the  7 driest  months totaled od.l centimeters.

By comparing these data with a desired sludge cake end  product of at  least
40% TS for subsequent stockpiling,  it is  theoretically  possible  to establish
the optimal  sludge loadings for any particular season.   Table  26 summarizes
the net evaporation requirements over a 12  month and 7  month period at  load-
ing rates between  15.24 and UI.92  centimeters per application.  Based  on
the 1973 through 1974 meteorological  data there  is a net evaporative  rate of
58.7  centimeters per year.   Then the maximum  liquid  sludge  depth possible for
a 40% TS sludge cake equals 6b.O centimeters.  The 7 driest months of the year
(June-December) have a net evaporative rate of 38.1  centimeters; thus,  the
maximum liquid sludge load possible for obtaining a  40% TS  sludge equals 42.3
centimeters.

It should be pointed out that  these are hypothetical figures based on evapora-
tion  of pan  water.   Water obtained  in partially  dried  sludge will be  under ca-
pillary forces; therefore,  decreasing the net evaporative effect.

One of the problems associated with drying  the sludge  was the  development of
a thin, dried sludge crust on  the  basins' surfaces.  The hydraulic conducti-
vity of this dried crust is severely reduced, preventing the capillary move-
ment of water to the surface from  the saturated  sludge  below.  The effect of
this  crust is evident when the TS  content of  basin B is compared with basin E.
Basin E was  lined with plastic; therefore,  all water losses were from evapora-
tive losses.  Because of this  crust development  basin  E did not  dry.   Basin B
lost water through percolation rather than  evaporation. Another approach be-
ing studied is the addition of thin layers  of liquid sludge (0.6 centimeters
per application).   In this way it  is hoped  that  there  will  be  no significant
crust development covering a pool  of liquid sludge.

The odor level was not usually significant except for  a brief  period.  The
most intensive odors were encountered after the spring thaw of frozen sludge
in the drying basins.  There were neither odor nor other nuisance  complaints
by any of the neighbors.  Many small flies or gnats accumulated over the ba-
sins during the last half of August, but did  not assume nuisance proportions.


                                     53

-------
Table 26-Net evaporation  required  (centimeters  per year) at various sludge
                               loading  rates
Sludge loading in
Variables
Water load @ 4% TS (cm)
Precipitation 1973-1974 (cm/yr)
Total water load (cm/yr)
Final sludge volume required
G> 40% TS (cm)
Gross evaporation required (cm/yr)
Precipitation June- December (cm/-
season)
Total water load (cm/season)
Final sludge volume (cm) required
(3 40% TS
Gross evaporation required (cm/-
season)
15.24
14.7
34.0
48.7
1.5
47.2
20.3
35.1
1.5
33.5
30.5
29.2
34.0
63.2
3.0
60.2
20.3
49.5
3.0
46.5
61.0
58.4
34.0
92.4
6.1.
86.4
20.3
78.7
6.1
72.6
cm/year
91.4
87.9
34.0
121.9
9.1
112.8
20.3
108.2
9.1
99.1

121.9
117.1
34.0
151.1
12.2
144.0
20.3
137.4
12.2
125.2
Chemical data indicated that the sludge lost considerable  quantities  of  ex-
tractable NH4-N (from about 5,000 ppm to 2,000-3,000 ppm)  but little  NOs-N
accumulated in the sludge.   Apparently, NHj was  volatilized or nitrified,
and the NOs was denitrified below the surface.

On January 15, 1974 101.6 centimeters of anaerobically digested sludge  (ap-
proximately 71,000 liters)  from the Fort Collins Sewage Treatment Plant  were
loaded into a lined drying basin (designated basin G).  A  sampling program
was designed to obtain weekly samples from three locations at three different
depths for nitrogen analysis.  Table 27a summarizes the nitrogen concentra-
tions while Table 27b summarizes the nitrogen concentration as a percent of
the total solids concentration of the three stratified samples.

Within 4 weeks of the initial loading approximately 38% of the TKN was  lost.
Most of this loss occurred in the bottom and middle layers of the stratified
basin, and changed little thereafter.  Within 6  weeks of the initial  loading,
approximately 75% of the NH4-N had been lost and again most of the loss  occur-
red in the bottom and middle layers.  During the  sixth week, solids from  the
bottom  layer floated to the top stratum which tended to raise the N concentra-
tions of  the top and middle layers.

The variations in other chemical determinations  followed no definite pattern,
neither  increasing nor decreasing with time, and are shown in Table 28.
                                      54

-------
Table 27a-Nitrogen concentration of 3 layers of liquid sludge in drying basins'


Date sampled
1/23/74
2/5
2/12
2/19
2/16
3/5


bottom
2,850
1,300
780
740
725
700

NH4-N
middle
3,230
1,340
•760
750
700
750


top
590
1,000
660
675
450
700


bottom
4,500
2,980
3,250
2,860
3,090
2,640
mg/1
TKN
middle
4,710
2,720
2,910
3,040
2,150
2,690


top
644
664
716
636
448
1 ,650.


bottom
0.50
0.05
2.20
0.80
0.20
0.65

N03-N
middle
1.05
0.20
2.35
0.50
0.40
0.65


top
0.45
0.25
0.01
0.45
0.10
1.65
 Table 27b-Nitrogen concentration as a percent of  the  total  solids  concentration
                        of the three stratified  samples
Date sampled
1/23/74
2/5
2/12
2/19
2/26
3/5


bottom
6
2
1
1
1
1
.2
.2
.3
.3
.3
.2

NH4-N
middle
9.0
2.7
1.4
1.3
1.2
1.3


top
11.3
14.3
11.0
11.3
10.0
1.8


bottom
9.8
5.2
5.3
5.2
5.6
4.4
X
TKN
middle
13.1
5.6
5.2
3.2
3.6
4.6





N03-N
top bottom middle
12
9
11
10
9
4
.4
.5
.9
.6
.8
.1
N*
N
N
N
N
N
N
N
N
N
N
N
top
N
N
N
N
N
N
     * N mean negligible.
                                         55

-------
Table 28-Range in  various chemical  constituents  of liquid  sludge contained in
                               drying basins
Chemical constituent
* Volatile solids
Conductivity umhos/cm
PH
P* (ppm)
K** (ppm)
Zn*** (ppm)
Cu (ppm)
Fe (ppm)
Mn (ppm)

42
4.5
7.2
650
690
285
34
150
4.8
Range
- 70
- 7.1
- 8.5
- >1000
- >1000
- 505
- >50
- 310
- 11.4
                *  Sodium bicarbonate  extractable P.
                **  Ammonium acetate extractable K.
                *** DTPA extractable Zn, Cu,  Fe and  Mn.
Conclusions^

This study indicated that earthen drying basins with more than  50.8  centi-
meters of sludge will not dry rapidly enough to allow yearly  removal  of  dried
sludge.  Comparisons of lined and unlined basins demonstrated that most  of
the water loss was through soil percolation and not evaporation.  The forma-
tion of a thin dried sludge crust prevented evaporation  from  taking  place at
the sludge surface.  If this sludge crust could be constantly broken up  and
reincorporated into the wet sludge or prevented from forming  through appli-
cations of thin layers of liquid sludge, it would be theoretically possible
to dry as much as 43.2 centimeters of liquid sludge per  year.   During the
drying process, about 45% of the total N content is lost through  leaching,
volatilization or denitrification.
                                     56

-------
           FUTURE AGRICULTURAL  RESEARCH  AND DEVELOPMENT  PROJECTS
In 1975, a comprehensive $418,000 researcn program  consisting  of  10  projects
was approved by the Metro Board of Directors.   This agricultural  research
program was designed to obtain additional  information  on  various  aspects of
sludge recycling to land, and to answer some of the questions  raised in  the
Environmental  Protection Agency Technical  Bulletin  No. 430/9-75 titled "Ac-
ceptable Methods for the Utilization or Disposal  of Sludges".   The projects
included:
   1.  Investigation of drying basin optimization.

   2.  Sludge characterization to define chemical and biological constituents
       of Metro sludge.

   3.  Investigation of detention times and otner conditions required to re-
       duce to acceptable levels viruses and other potential pathogens.

   4.  Nitrogen management: to enhance or diminish nitrogen concentration in
       sludge depending on intended use.

   5.  Greenhouse and  crop rotation study.

   6.  Heavy metals monitoring.

   7.  Heavy metals monitoring of soil  receiving cumulative sludge loadings.

   8.  Subsurface injection of liquid  sludge.

   9.  Mine tailing reclamation.

   10.  Investigation of  heavy metals as  it  effects the  food chain from  sludge
       to  the  tissues  of  animals  grazing  on  vegetation  grown on a sludge-soil
       mixture.
 Metro is  also working with  the U.S.  Geological  Service  and  the  Colorado  State
 Geologist Office to investigate the  effect  of heavy  loadings  of sewage  sludge
 conditioned with chemicals  on  ground water  at the  Lowry Bombing Range.

 A summary of project objectives and  scope of work  follows.
                                       57

-------
DRYING BASIN PROJECT

Objective

To obtain information on a continuous loading basis required for development
of a relatively problem-free operations scheme to manage 600 acres  of drying
basins at the proposed sludge drying and distribution site.


Scope of Work

1.  Anaerobically digested liquid sludge (primary and mixed  primary plus se-
    condary) are being added to earthen drying basins to determine  optimum
    loading rates and drying times.

2.  The loading rates are intended to simulate fullscale loading rates tu ba-
    sins at a sludge drying and distribution center.

3.  Four separate drying basins, each 0.1  hectares, are being utilized.   The
    basins are unlined and without underdrains.

4.  Acceleration of drying rate of 101.6 centimeters  of sludge is being inves-
    tigated by.

       A)  Decanting supernatant liquor (less than 1.0% total solids).

       B)  Mechanical agitation using surface drag.

5.  Special emphasis will be placed  on evaluating seasonal  effects  as they re-
    late to hindrance of drying with each successive  liquid  sludge  loading to
    previously dried sludge.

6.  Information obtained from successive loadings will  be used to determine
    strategy for dried sludge removal  and storage.

7.  The practical  problems involved  in removing  thin  layers  of dried sludge
    mixed with soil  will  be investigated.

8.  The Northern Colorado Research Demonstration Center (NCRDC)  at  Greeley,
    Colorado is the site for this investigation.  The research farm provides
    an excellent demonstration to the farm community  of the  benefits of this
    project.

9.  Each basin is  being monitored for:

       A)  Water loss by percolation.

       B)  Quality of the water percolating through the soil profile.

       C)  Nitrogen changes in the sludge as a function of drying time.

       D)  Odors and vectors.
                                      58

-------
     E)   Change  in  soil  permeability with successive applications of liquid
         siudge.

10.   The Fort Collins  treatment  plant  is the  source of  liquid anaerobically
     digested primary  plus  secondary sludge,  while the  Denver North Side
     Treatment Plant is  the source  of  anaerobically digested primary sludge.


11.   The air dried sludge will  be cured in  a  stockpile  for  several months.
     The effect of drying time  on pathogen  reduction will also  be monitored.


SLUDGE CHARACTERIZATION

Objective

1.  To obtain data concerning concentrations  and seasonal  variability  of
    those parameters (heavy metals, nutrients, etc.)  used by regulatory
    agencies to establish guidelines for land application of stabilized
    sludge.


Scope of Work

1.  Metro  laboratory is  analyzing monthly composite sludge samples for ferti-
    lizer  elements  (TKN, NH^, total P and total K) and heavy metals (total Zn,
    Cu, Ni,  Cd, Pb, Cr).


PATHOGEN STUDY

Objective

1.  To  determine  relative  concentrations and variability in the anaerobically
     digested sludge of  certain  viral  and parasitic organisms having public
     health significance.

2.   To  determine  the  survival  rate of the  pathogens in the soil-sludge mix-
     ture.   Particular  emphasis  will be placed on  the minimum detention  time
     required between  sludge application to land and the  growth of crops  dest-
     ined for human consumption.


Scope of Work

 1.   The Biological Waste Management and Soil Nitrogen  Laboratory  of  the Agri-
     cultural Research Service  at Beltsville, Maryland  will provide  the analy-
     tical  services and research direction  for this  study.

 2.   Survival rates of endemic  salmonellae  and ascaris  ova  in  digested sludge
     as it is dried and stockpiled will be  determined  to estimate  the  air dry-
     ing or storage time needed to eliminate  these organisms.


                                       59

-------
3.  Sewage sludge at the treatment plant will  be seeded with f2 bacteriophage.
    The survival of f2 bacteriophage, which closely resembles the enteroviru-
    ses (poliovirus, coxsackievirus,  echovirus and reovirus) physiologically,
    will be examined to estimate the survival  rates of other viruses  which
    are difficult to impossible to identify in sludge.


4.  The liquid sludge will  be applied to the sludge drying basins at  Greeley,
    Colorado.  Samples of the sludge  will  be collected every 2 weeks  for  path-
    ogen and virus analysis.


5.  Sampling will continue long enough to establish the survival  times  of the
    organisms.
NITROGEN MANAGEMENT PROJECT

Objectives

1.  To prevent nitrate pollution of ground waters.

2.  To maintain the nitrogen fertilizer value in the sludge that is  to be
    marketed.


Scope of Work

1.  The staff  of the Department of Agronomy at CSU  will  conduct the  laboratory
    phase of this project during the first year.

2.  Upon successful completion of the laboratory phase of this study,  a second
    phase field experiment may be recommended to verify on a large scale re-
    sults obtained from the lab study.
                                                                      15
3.  A laboratory bench anaerobic sewage sludge digester has been fed N   en-
    riched ammonia in order to incorporate the labeled nitrogen isotope into
    both the organic and inorganic nitrogen compounds of the digested  sludge.

4.  The N   enriched sludge will be added at various loading rates to  soil.
    After suitable detention periods, the soil-sludge mixture will be  quanti-
    tatively analyzed for NH/;, N03, N20, NO and N2  by mass spectrometry.
    This analysis will determine the rate of denitrification occurring in
    the soil-sludge mixture.

5.  Gas samples will be taken from enclosed incubation vessels for determining
    C02, CH4,  NO, N20 and N2 gas production.  A comparison of gas chromato-
    graphy and mass spectrometry results will enable determination of kinetics
    of mineralization, nitrification and subsequent denitrification  of organic
    nitrogen forms.
                                      60

-------
GREENHOUSE AND CROP ROTATION  STUDY

Objecti ves

1.  To determine the influence of anaerobical ly digested  sludge  at various
    loading rates on germination, growth and yields  of crops  grown in  Colo-
    rado.

2.  To apply information obtained from greenhouse tests for validation in  the
    field under varying crop  rotation schemes typical  of  farm practice in  Co-
    lorado.

3.  To determine the extent to which anaerobical ly digested sludge may be  sub
    stituted (in whole or in  part)  for other types of commercial or organic
    fertilizers as presently  used by the farm community,


       ofWork
4.
    The greenhouse portion of this study will be conducted during two seasons,
    namely:
       A)   Cold weather germination (15.5°C j^2°).

       B)   Wan.i weather yermiiiacion (24°C^2°).
'
-------
HEAVY METALS UPTAKE

Objectives

1.  To determine the uptake of heavy metals (Zn, Cu, Ni, Cd, Cr and Pb)  into
    crops commonly grown in Colorado.

2.  To determine the extent to which heavy metals become more available  or
    less available to crops after sludge application to soil.


Scope of Work

1.  Two rates of sludge (336 and 670 dry metric tons/hectare) have been  added
    to experimental plots at the NCRDC at Greeley, Colorado.  Total  DTPA and
    water extractable soil metals are being correlated with plant uptake and
    possible yield depression.

2.  Metal salts equivalent to 336 and 670 metric tons/hectare have been  added
    to additional plots to compare availability of sludge born metals to metals
    in soils without organic matter additions in relation to plant uptake.

HEAVY METALS MONITORING PROJECT

Qbjecti ves

1.  To determine the long-termcumulative effects of repeated applications of
    sludge on buildup of toxic metals  in soil  or plant material at the Watkins
    research site.


Scope of Work

1.  The 0.8 hectare site consists of 72 plots.   Thirteen of the plots have
    never received sludge and are used for baseline data comparisons. Loadings
    of sludge between 20 and 200 dry metric tons per hectare were applied dur-
    mg the first year (1971) to 59 plots.   The sludge was  subsequently  incor-
    porated into the soil  by discing and plowing.

    During the second year (1972) liquid sludge loadings between 20 and  43 dry
    metric tons per hectare were applied by subsurface injection to 32 of the
    59 plots that received sludge in 1971.

    During the third year (1973) no sludge was  applied to any of the 72  plots.

    During the fourth year (1974) liquid sludge was applied by subsurface in-
    jection to 36 of the original 59 plots receiving sludge in 1971  at loadings
    between 11.2 and 22.4  dry metric tons per hectare.

2.  The Watkins  research site monitoring will  be continued  for another 2 years
    until  the  full  scale drying  distribution site  is in operation.   The  deci-
    sion  to phase out the  Watkins site will  be  determined by the analytical re-


                                      62

-------
    suits obtained during  this  perioci,

3.   Winter wheat will  be planted  annually  on  all of  the  '12 test plots.  Sup-
    plemental  irrigation will  be  provided  as  necessary to ensure germination
    and growth despite fluctuations  in  precipitation.


SUBSURFACE INJECTION PROJECT

Objectives

1.   To develop backup technology to  the air drying system  capable  of  year
    around handling of anticipated sludge  producuon at  the  full  scale  reuse
    site.  Particular emphasis will  be placed upon injection into  frozen  soils.

2.   To demonstrate the technical  and economic advantages of  subsurface  injec-
    tion for liquid nutrient application and crop growth.


Scope of Work

1.   The duration of this project is  anticipated to be 2 years (1976-1977).

2.   Metro will purchase or lease existing injection equipment for both shallow
    and deep  (0.3 to  1 meter) injection.  This equipment will be modified as
    required  to ensure frozen ground capability, uniformity of sludge distri-
    bution and minimizing power requirements for either beneficial recycle or
    disposal  modes of operation.

3.  The nearest recommended injection site available is at  the LBR.  Eleven
    hectares  of land  which has never received sludge will be used for this pur-
    pose.

4.  The  liquid  sludge will be transported from the central  plant  to  Lowry by
    means  of  a  6,000  gallon tank truck whicn will then be connected  to the
    subsurface  injection  device by a hose.  The subsurface  injector  will  be
    pulled by a tractor.

5.  Effects of  subsurface injected  liquid sludge on yield will be evaluated for
    native pasture  land  and winter wheat.

6.  Soils  and foilage will  be  analyzed  for nutrient and heavy metals content.


MINE  TAILING  RECLAMATION PROJECT

Objectives

 1.  To demonstrate the  beneficial effect  of  applying  anaerobically digested
    sludge for reclamation  of rock  and mine  tailings  in  forested  mountain areas
    of Colorado.
                                       63

-------
Scope of Work

1.  The site being investigated is located at the base  of Berthoud  Pass at
    the recently abandoned Urad molybdenum mine.   Approximately  100 hectares
    of mine tailing wasteland will require reclamation  over  the  next few years.

2.  During 1975, approximately 12 hectares of tailings  received  a mixture of
    sludge and wood shavings.  During 1976-1978 20 hectares  per  year will be
    reclaimed requiring approximately 2.240 dry metric  tons  per  year of sludge
    from Metro.  Growth response and  environmental  factors will  be  evaluated.


ANIMAL UPTAKE PROJECT

Objectives

1.  To determine whether and to what  extent contamination of tissues in cattle
    grazing sludge applied land has occurred which could  represent  a hazard to
    human health.

Scope of Work

1.  Representative mature beef cattle from the LBR sludge recycle site and
    from a control herd have been slaughtered.   Tissue  analysis  of  liver, kid-
    ney, muscle, blood, bone, fat and brain is presently  being analyzed for
    heavy metals and toxic organics.

2.  An extensive survey of sludge, soil  and vegetation  at the LBR and a control
    site is presently underway.  Samples are being analyzed  for  the same chemi-
    cal constituents being determined in the animal  tissues.

3.  Beef cattle similar to those at the  LBR have  been fed Metro  Denver sewage
    sludge as a percentage of their diet to determine the effect of direct in-
    gestion of larger amounts of sewage  sludge on edible  animal  tissues.
GROUND WATER QUALITY AT THE LOWRY  BOMBING RANGE

Objectives

1.  To investigate the effects that sludge disposal  at the LBR has  had  on
    ground water quality.


Scope of Work

1.  Determine the location and extent of alluvial  aquifers,  direction of ground
    water movement in the shallowest bedrock aquifer.   This  is being accomplished
    by drilling some 60 wells at various depths  in and around the sludge recycle
    s i te.
                                      64

-------
2.  Quality of ground water upgradient and  downgradient  from  the  recycle  site
    is being monitored for pathogens,  alkalinity,  sulfates, chlorides,  phos-
    phates, nitrogen, COD, organic carbon,  dissolved  solids,  hardness and me-
    tals (Na, K,  Ca,  Zn,  Fe, Pb,  Cr,  Cu,  Ni,  Mn,  Cd).
                                      65

-------
                          SUMMARY AND CONCLUSIONS
Processing and ultimate disposal  of wastewater sludge  is  one of the  most
costly unit processes within any  sewage treatment plant.   Since 1969 Metro
nas been examining methods of jiudge disposal  which  are economical and  en-
vironmentally safe.  Prior to 1969, all of the sludge  produced  by Metro was
either flash dried, incinerated,  or lagooned.   The dried  material  was used
as a fertilizer on city parks,  wnile the incinerated material was landfilled.
However, due to continuous mechanical  and air  pollution problems the flash
dryer-incinerator units were permanently shut  down in  August of 1971.

Since 1971 the only mode of sludge cisposal  used  by  ,'ietro has been land ap-
plication.  A number of different disposal  procedures  have been tried over
the intervening years.

During 19b9 and ly/U the VJLJU,,, filter cake  sludge,  which could not  be  pro-
cessed by the FDI units, was transported by  truck to the  LBR.   Two methods
of incorporation were utilized, one for dry  weather  and  tne second for  wet
weather,  ury weather operations  consisted of  tailgating  the sludge  directly
from the transport vehicle onto the soil surface.  The sludge was then  thinly
spread over the surface with a  front mounted blade on  a  dozer.   The  sludge
was allowed to dry for 14 hours and then rototilled  in.   This operation was
not always satisfactory because large rocks, dense vegetation,  or wet soil
would clog or render the rototiller inoperable.

During wet weather, or when the ground was frozen, sludge was mixed  directly
into the soil  using a front mounted blade on a dozer.   A  satisfactory mix
was accomplished when approximately 5 parts  of soil  were  mixed  with  1 part
of sludge.  However, this operation was not  satisfactory  due to the  economics
of a '^\ hour per day operation  and its inherent difficulty.

Because of these problems, several changes in  sludge application methodology
were adopted.   At the LBR site  a  ramp was constructed  which allowed  the trans-
port vehicles  to load sludge directly into farm manure spreaders. The  sludge
was then spread onto native pasture land at  the rate of  about 6.7 metric  tons
per hectare.   After the sludge  had dried, about a half hour, a  spiked tooth
harrow was used to break any large clumps of sludge  into  fine particles.
This method proved satisfactory for one year,  however, during the late  spring
of 1972 when the area had dried,  small smoldering fires  started in the  areas
which had received many consecutive sludge applications,  a result of careless
smokers and heavy equipment operating in the area.  These fires proved  diffi-
cult to extinguish, particularly in high winds.   Other problems arose when
the contractor experienced difficulty with access to the  field.  As  a result,
large quantities of vacuum filter cake were  stockpiled to a depth of about
]  .2 meters in a depression.  Shortly thereafter snowstorms covered the  stock-

                                      66

-------
piled filter cake.   As  the  snow began to melt, the waste activated and raw
primary sludge began to decompose creating odor nuisances to residents living
adjacent to the area.

Because of the fire and odor nuisances  a new  method of land application was
started in June of 1972.   The sludge  was spread 5  to 8 centimeters in depth
and then plowed under within 6 hours  of application.  Crops such as wheat,
oats or sudangrass were planted to  reduce  soil erosion,  and to provide forage
for the cattle that continuously  grazed the  land.  This  method has been pro-
viding satisfactory control of odor and fire  problems since 1972.

Special modifications were adopted  during  winter  operations when  the  soil  is
frozen and cannot be plowed.  Since 1973 an  inclement weather  site has been
prepared in advance by bench and  terracing the area.   Inclement weather opera-
tions generally take place during December,  January  and  February,  depending
upon the severity of the winter.   During  the relatively  mild,  dry winter  of
1974-1975 the inclement weather site was  required for only 30  uays ouring
January and February.

Vacuum filter cake sludge disposed of at  the LBR is  a mixture  of raw primary,
waste activated and anaerobically digested primary sludge.  Continuous sludge
loadings since 1969 have increased the \-\ content of the soil  to excessive
levels beyond any capacity  for cr^p removal.  However,   this may not pose a
serious threat to ground water quality due to the fact  that rainfall is limi-
ted  and the potable ground  water is protected for the most part by impervious
stratum within the  regolith.

Sludge additions  have  increased the K, P, salt and organic matter content of
the  LBR soils, but  not to  levels that  could  be considered excessive or out of
the  normal  for agricultural  soils  in this area.   The heavy metal content  has
increased  significantly, whether this  has been detrimental to crop growth is
unknown.   However,  it  is doubtful  since tissue analysis of plant  samples  has
not  shown  levels  that  would be considered out of  the normal elemental compo-
sition  range  for  plant materials.

By 1971  it became apparent that  land application  of wastewater sludge was not
going  to  be a temporary  expedient,  but rather a  long term necessity.  There-
fore,  a  number of studies  were entered into  to evaluate the effects  of sludge
on environmental  concerns  and crop response.

A field experiment was set up at Watkins, Colorado to evaluate  the  effects
of various sludge loadings to crop germination and subsequent growth.   Re-
 sults  indicated that there was a  severe inhibition of germination when mil-
 let or sorghum sudangrass  were planted immediately after  sludge  incorporation.
 However,  this inhibition was eliminated when the  sludge was allowed  to  incu-
 bate in the soil  for two months.   Wheat yield data showed  increased  yields
 with application rates of 25 and 5(J dry metric  tons  per hectare.

 Microbial counts taken 6 months  after  sludge incorporation demonstrated  that
 there were no differences in fecal coliform bacteria between  the sludged plots
 and the control  plots.
                                       67

-------
 The  studies  conducted  at Watkins  led to a greenhouse investigation in which
 a  number of  soil  sludge mixtures  were utilized to evaluate the effects of
 various  incubation  periods on germination and plant growth,  Results demon-
 strated  that sorghum sudangrass was inhibited the most by sludge additions,
 while  corn was  intermediate  in tolerance, and wheat was the least affected
 of the three crops  tested.   There appeared to be no inhibition of germination
 and  emergence of  wheat and corn after a soil sludge incubation period of 1
 month.   Of the  sludge  types  used, dried sludge had the fewest adverse effects
 on germination.

 Metro  has been  investigating the possibilities of air drying liquid anaero-
 bically  digested  sewage sludge in shallow, earthen drying basins,  Data col-
 lected from  experimental drying basins demonstrated that more than one-half
 of the N  content  of the sludge is lost during the air drying process.  Com-
 parisons  of  plastic lined and unlined basins demonstrated that most of the
 water  is  lost through  soil percolation and not evaporation.

 It is  important to  realize that the recycling of organic matter is not a
 new  process,  but  one that has been occurring for eons, since the beginning
 of life  itself  and  is  essential  for its very maintenance.  Oryanic matter
 represents a  stockpile of energy, one that should not be wasted.  With the
 realization  that  fossil fuels (recycled organic matter) are coming in short
 supply,  it becomes  evident that ^ waste any source of energy is self defeat-
 ing.   It  is  interesting to note that the word waste is often applied to human
 and  animal excreta  when in a biological  sense it is not a waste.  In fact,
 the  only justification for the term "waste"  is that a potential  source of
 energy has been wasted.

 Unfortunately, there are problems associated with the recycling of sewage
 sludge.  Much of our sewage is not derived from garbage or fecal material,
 but  is the product of industrial  waste.   Modern society tends to centralize
 and  concentrate industry,  which is reflected in the wastewater treatment
 plant.  Thus, metals or exotic organic compounds such as pesticides which
 are  products or by-products of industry turn up in sewage sludge.  In addi-
 tion to these elements and compounds there is a disease hazard.   The prob-
 lems in dealing with these elements, compounds and biological  agents become
 particularly acute when sludge is to be recycled into agriculture and the
 food chain.

 If sewage sludge is to be  utilized as  an agricultural  resource,  the authors
of this report feel that there are a number  of areas which will  require future
 research efforts.   These include  public health aspects, plant response and
 food chain effects from heavy metals,  the true fertilizer value  of sewage
 sludge as measured by crop response, and particularly,  public awareness or
acceptance of sludge as a  resource.

 Under the heading  of public health aspects fall  a number of issues or problems.
The most immediate  is whether or  not utilization of sewage sludge on agricul-
 tural land represents a health hazard.   Pathogens are known to survive the
sewage treatment process,  but the threat to  public health has not been ade-
 quately evaluated.  Research efforts are needed to determine the survival rates
of enteric pathogens (parasites,  bacteria and viruses).


                                      68

-------
Since there is the possibility  that  cattle may  ingest  quantities of  sludge,
i.e soil  or from dust  on  forages,  the  health  effects on  livestock or humans
consuming the livestock should  be  evaluated.

Another public health  aspect would have  to include  possible  food chain effects
of heavy metals on crops, animals, and humans.   Little is  known about the  tol-
erance or uptake rates of plant species  and varieties  under  different soil,
climate and management practices.  Metals that  should  be studied include As,
B, Cd, Cr, Cu, Hg, Ni, Pb, Se,  and Zn  because of their potential toxicity  to
plants or hazard to livestock and  humans.

If sewage sludge is to be handled  as a resource, specific  data evaluating  its
effects on crop yield  and quality  should be made available to the potential
user.  Responses of various crops  should be evaluated  for  different  manage-
ment practices which would include loading rates, soil pH  levels, climate,
irrigation or water relationships, timing of  application,  methods of incor-
poration different forms of sewage sludge (i.e. dried, liquid, dewatered),
and rates of nutrient  removal or availability.

And finally, the public will have  to be  educated and made  aware of  the econo-
mical and ecological advantages of recycling  sewage sludge in order  to counter
existing cultural prejudices against wastewater sludge.
                                      69

-------
                                      APPENDIX A




Table 29-Analysis of Lowry Bombing Range soils sampled spring of 1972
Site no.
U




IB



1C



2A




28



*C



3A


38



3C



Soil
depth
Inches
0-6
6-12
12 - 24
«4 - 36
36+
0 - 6
t> - 12
12 - 24
24 - 36
0-6
6-12
12 - 24
24 - 36
0-6
6 - 1Z
12 - 24
24 - 36
36+
0-6
6-12
12 - 24
24-36
0 - 6
6-12
12 - 24
24 - 36
0-6
6-12
12 - 24
0-6
6 - 12
12 - 24
24-36
0-6
6-12
12- 24
24-36
PH
saturated
paste
7.5
7.9
8.2
6.3
S.I
7.9
8.1
6.2
8.1
7.0
7.0
e.o
8.3
7.5
7.7
8.0
8.3
8.4
7.3
7.S
6.3
8.5
6.9
7.0
8.2
6.0
7.3
7.2
6.1
6.6
7.3
8.0
7. 
O.u
0.6
5.4
7.3
3.;>
0.6
1.5
0.9
O.b
3.0
O.b
1.4
O.b
1.*
O.b
0.4
0.4

NaiiCOa
P
13.0
2.0
2.0
4.8
6.5
11.3
2.0
2.C
2.3
18.3
12.5
2.8
7.0
49.3
7. 0
5.3
4.C
6.3
35. »
6.5
6.0
5.3
42.5
21.3
46.b
9.0
110.6
12.0
3.S
50.3
3.S
3.K
4.0
135.0
7.8
9.0
6.5

NH4-N
8
8
C
6
4
6
4
4
4
4
6
4
4
4
4
4
4
2
12
6
4
4
6
4
4
4
34
6
4
20
6
4
4
36
C
6
4
mq/kq
Cl
saturated
paste
b'.OO
5.00
12.51
16.66
41. 6s
14.29
6.24
8.33
12. SI
24.99
12.51
12.51
12.51
174.95
412.39
374. 6B
24.99
62.50
124.96
337.41
62. SO
224.93
11.51
137.48
137. «S
374.88
S99.69
224.93
«9.98
412.40
41Z.40
449.86
1449. S»
474. 8S
167.46
62.50
74.96

OTFA
Zn Cu Mo Ft
j.b
3.i
4.3
2.3
2.S
3.1
i.S
2.5
2.b
31.0
7.5
2.5
1.3
1S.1
4.1
2.7
i.3
!.fc
16. S
4.6
3.5
2.3
£9.0
21.7
3.S
2.0
40.0
TO.S
2.8
76.0
9.7
3.7
2.2
41.0
7.1
H
2.6

-------
Table 29-continued
Site no.
4A



4B



4C



SA



SB




1C



4A



6B



(C


Sol)
depth
Inches
0-6
6-12
11 - 24
24 - 36
0-6
6-12
12 - 24
24 - 36
0-6
6-12
12 - 24
24-36
0-6
6 - U
12, - 2A
24-36
0-6
6-12
12 - 24
24-36
36+
0-6
6-12
12 - 24
24 - 36
0-6
6 - 12
12 - 24
24-36
0-6
6-12
12 - 24
24-36
36+
0- 6
6- 12
12 - 24
24 - 36
pH
saturated
paste
7.6
7.2
7.9
8.0
l.i
8.0
0.2
7.9
7.7
7.8
«.*
8.3
7.6
7.7
8.3
0.1
7.9
7.8
7.9
7.6
7.4
7.3
7.6
7.9
8.0
7.3
7.8
8.5
8.0
7.7
6.3
7.8
7.9
7.9
7.3
8.1
7.9
ft.O
Cond.
•mhos/car
1.9
1.0
0.7
0.7
2.4
1.3
2.4
S.I
2.8
2.0
1.0
0.6
0.6
0.7
0.5
1.1
1.6
1.0
O.S
2.0
3.*
1.6
0.6
0.8
1.1
2.8
3.2
1.4
2.0
3.8
1.1
9.0
22.0
20. 0
6.0
1.4
0.6
20.0
TUN
S
0.219
0.090
0.059
0.045
0.192
0.065
0.036
0.031
0.287
0.105
0.055
0.038
0.1 55
0.103
0.047
0.029
0.148
0.051
0.034
0.023
0.021
0.1«
0.091
O.Obl
0.034
0.119
0.068
0.044
0.031
0.179
0.055
0.033
O.°025
0.026
0.342
0.071
0.040

N03-N
9.8
2.0
0.8
0.4
4.8
1.6
0.8
0.8
21.0
3.5
0.3
0.4
4.6
0.6
0.4
0.4
6.8
1.2
0.0
0.4
0.9
7.S
2.0
0.8
0.0
9.8
0.0
0.8
0.4
11.8
0.8
O.t
0.8
o.fl
10.1
1.4
0.6

NaHCOs
P
122.0
4.3
1.3
2.6
936.0
9.0
11.0
10.3
174.0
15.5
13.0
12.0
62.6
9.0
6.0
4.0
100.6
11.3
2.3
4.0
9.0
72.6
8.3
2.3
4.0
46.3
3.0
3.5
3.5
113.6
6.0
8.3
10.5
9.5
183.0
6.5
8.8

NH4-N
50
6
6
4
46
6
4
6
58
U
6
6
20
8
6
6
32
8
6
6
6
28
6
10
20
30
10
10
10
36
10
10
10
8
5ft
10
8
8
roq/ko
Cr^
saturated DTPA
paste Zn Cu
199.94
137.48
87.50
74.98
374.88
224.93
287.43
462.37
274.91
424.37
62.50
74.98
49.98
99.97
37.5)
74.98
199.94
137.48
24.99
24.99
49.98
99.97
62.50
124.96
162.47
124.96
724.78
174.95
199.95
724.78
149.95
562.34
987.21
1324.59
1324.59
312.42
574.82
1524.53 	


Ho Fe
31.5
17.6
3.5
2.7
70.0
7.1
2.4
1.2
45. 0
7.6
5.8
4.6
17.3
6.5
4.2
2.5
16.2
4.1
3.3
3.4
5f
.6
27.5
8.4
3.7
3"j
.3
91 T
tJ. J
Sri
-U
3Q
.3
2O
. 7
17?
1 -Jt £
*T 7
9* /
3 2
J»t
1 Q
1*7
1.9
26.3
5.9
2.3
2.5

-------
          Table 29-continued
—I
ro
Site no.
XA
KB
KC
7A
7B
7C
Soil
depth
Inches
0 -
6 -
12 -
24 -
0 -
6 -
12 -
24 -
0 -
6 •
12 -
24 -
0 -
6 -
12 -
24 -
0 -
6 -
12 -
24 -
0 -
6 -
12 -
24 -
6
12
24
36
6
12
24
36
6
12
24
36
6
12
24
36
6
12
24
36
6
12
24
36
PH
saturated
paste
7.5
ISS
7.9
8.0
8.0
7.4
8.0
7.8
7.5
ISS
7.6
8.6
9.1
b.S
8.5
8.0
7.1
7.0
7.8
7.5
7.5
6.1
8.3
8.1
Cond.
anhos/cmz
1.7
ISS
2.8
2.6
8.0
6.0
5.0
6.0
6.0
ISS
5.0
2.8
0.4
0.5
1.5
3.8
0.7
0.3
0.5
1.1
0.4
0.4
0.5
4.0
TKN
X
0.817
0.170
0.053
0.040
0.307
0.114
0.118
0.142
0.179
0.042
0.020
0.021
0.114
0.053
0.036
0.026
0.154
0.083
0.044
0.026
0.149
0.105
0.051
0.033

N03-N
174.0
152.5
11.4
2.4
102.5
36.4
0.6
3.2
136.5
45.1
10.5
4.0
0.8
0.6
0.6
0.8
1.0
0.6
0.4
0.4
0.8
0.6
0.4
0.6

KaHCOs
P
276.5
115.0
22.3
23.0
93.0
143.0
100.6
119.0
288.0
32.3
19.0
14.0
8.3
0.0
2.0
2.8
13.8
4.0
3.5
2.8
10.3
0.5
0.5
2.6

NH4-N
24
96
14
22
20
50
130
144
20
18
16
10
12
16
10
8
14
14
9
9
9
12
9
16
r
£1
saturj
past
3323
574
374.
1224.
1324.
1149.
1362.
587.
349.
174.
49.
37.
249.
824.
49.
49.
49.
99.
49.
37.
49.
849.
ng/kg
ited
-e in
.97
.82
.88
.62
.59
.64
.09
.34
.39
95
.98
.51
92
74
98
98
98
97
98
51
98
74

DTPA
Cu Kn Fe
49.0
19.1
5.2
3.4
49.0
43.0
36.8
26.9
12.2
6.1
5.6
3.7
4.6
3.8
2.3
19.9
8.9
5.3
4.4
7.5
4.3
3.0
2.1
            ISS - Insufficient staple for analysis

-------
         Table 30-Analysis of Lowry Bombing Range soils sampled spring of 1973
CO
Site no.
1A




IB




1C




2A




2B




K




3A




3B


Soil
depth
Inches
0
6
12
24

0
6
12
24

0
6
12
24

0
6
12
24

0
6
12
24

0
6
12
24

0
6
12
24

0
6

- 6
- 12
- 24
- 36
36*
- 6
- 12
- 24
- 36
36*
- 6

- 24
- 36
36*
- 6
- 12
- 24
- 36
36*
- 6
- 12
- 24
- 36
36*
- 6
- 12
- 24
- 36
36+
- 6

- 24
- 36
36+
- 6
- 12
- 24
pH
saturated
paste
7.8
3.8
9.2
9.3
9.0
8.2
8.8
9.3
9.4
9.0
7.9
9.1
9.5
9.4
8.7
8.0
8.1
9.1
6.6
8.4
8.0
8.6
9.2
9.4
9.4
7.8
6.3
9.3
9.2
9.0
7.9
8.2
0.9
9.0
8.6
S.l
7.9
s.r
Cond. _
•mhos/car
0.05
0.08
0.08
0.09
0.22
0.24
0.08
0.09
0.18
0.28
0.06
0.09
0.13
0.27
0.50
0.08
0.04
0.13
0.33
0.70
0.10
0.11
0.11
0.12
0.12
O.OS
0.05
0.12
0.24
0.30
0.15
0.15
0.17
0.17
O.Z1
0.12
0.13
0.15


TKN NaHC03
t NOj-N P
0.10
0.08
0.05
0.03
0.03
0.12
0.08
0.05
0.03
0.02
0.09
0.08
0.04
0.03
0.04
13
3
1
4
4
12
2
0
0
2
21
4
4
11
9
0.19 2 20
0.07 2 20
0.06 3 20
0.04 8 10
0.03
i 9
0.15 4 25
0.11 2 8
0.05 5 6
0.03
} 7
0.02 3 5
0.15
5 77
0.08 2 2
0.06 3 3
0.06 10 11
0.04 5 16
0.17 40 25
0.11 51 68
0.06 50 9
0.05 33 23
0.05 10 25
0.10 24 62
0.07 49 5
0.08 35 2

NH4-AC
K
250
265
230
198
198
288
158
130
115
115
293
193
175
180
206
359
163
225
184
198
221
235
150
158
93
298
S30
353
225
205
304
500
298
225
201
334
216
206

NH4-N
7
5
5
4
5
4
5
3
4
6
5
5
5
4
5
5
5
4
5
6
6
6
6
4
5
5
5
4
4
5
8
7
5
6
7
19
6
8
mo/kg
	 C1 «'^
saturated
paste
2.1
2.8
2.1
2.1
2.1
2.8
2.1
2.1
2.1
2.1
2.1
2.1
2.5
2.1
2.8
2.1
2.1
2.1
2.1
2.1
2.1
2.1
2.8
2.1
2.1
1.1
2.1
2.1
2.1
2.1
2.1
2.1
2.1
2.1
2.8
2.1
5.0
3.9




nTDA
JH 	
1.08
0.40
0.57
0.43
0:15
0.69
0.2»
0.20
0.12
0.11
0.55
0.13
0.14
0.12
0.21
7.05
0.33
1.16
0.35
0.32
8.43
0.40
0.19
0.26
0.09
9.55
0.11
0.25
ISS
1.23
15.70
5. 85
0.21
1.01
1.16
3.20
0.«3
O.lb
Cu
1.15
1.02
0.94
1.09
1.31
1.22
1.02
0.66
0.52
0.40
1.27
1.11
0.77
0.65
0.74
4.70
0>72
1.49
0.60
0.76
7.10
1.45
0.93
0.65
0.35
7.40
1.07
0.93
ISS
1.46
9.40
3.11
0.74
1.17
1.17
3.60
1.13
1.00
Mr
20.60
11.30
6.45
3.55
2.50
26.50
8.50
6.70
3.10
2.05
22.50
11. IS
6.40
1.0S
6.00
tt.SO
13. bS
8.55
3. 55
1.6*
19.50
17. OJ
4. 95
3.35
.2.45
2s. 00
29.00
9. 53
ISS
3.30
50.50
19.00
6. 65
7.95
7.90
19. SO
13. CO
9.65
te
9.9
4.1
3.7
5.3
$.0
b.5
5.7
5.0
3.9
2.5"
9.9
4.9
4.3
3.6
3.9
16.1
7.1
7.2
4.1
3.9
19.5
7.6
4.7
3.6
2.3
29.2
13.0
5.2
ISS
3.7
35.0
17.6
5.3
a.o
7.2
10.4
5.3
3.6

-------
Table 30-continued
Site no.


3C




4A




4B




4C




5A




96




5C




Soil
depth
Inches
24

0
6
12
24

0
6
12
24

0
6
12
24

0
6
12
24

0
6
12
M

0
b
12
24

0
i
12
24

- 36
36*
- 6
- 12
• 24
- 36
36+
- 6
- 12
- 24
- 3*
36+
- 6
- 12
- 24
- 36
35+
- 6
- 12
• 24
- 36
36+
- 6
- 12
- 24
- 36
36+
- 6
- 1
0
47
21
29
27
10
73
7
2
3
5
13
tt
16
11
4
20
3U
2
1
1

NaHCOs
P
9
10
40
13
5
7
13
61
4
6
7
it
105
IS
9
7
18
54
7
S
6
18
114
13
7
10
19
I2r
17
23
14
17
61
9
6
T.
21

NH4-AC
V.
126
79
410
500
403
166
175
230
134
146
146
119
315
193
170
158
158
453
225
184
206
225
321
201
139
150
143
450
230
201
138
111
270
235
175
170
166

NH4-N
8
7
9
11
7
6
7
7
6
6
6
6
11
10
6
7
9
12
12
9
7
8
8
6
7
5
6
13
9
6
7
7
14
8
9
8
11
mo/kg
Cl
saturated
paste
5.0
3.9
3.9
C.2
3.9
3.9
6.0
2.1
2.1
2.1
2.5
3.2
2.5
1.4
.4
.4
.4
.4
.4
2.5
2.5
2.5
2.5
2.5
2.5
1.4
2.5
2.5
2.5
i2-5
Is
2.5
2.5
2.5
2.5
2.5
3.2




91PA
Zn
0.21
0.23
3s. 00
0.81
0.70
1.53
3.05
3.95
0.22
0.50
0.42
0.35
7.70
1.90
0.84
0.53
1.32
6.75
0.67
0.43
0.47
1.53
18.40
l.bl
0.83
1.34
2.90
13.20
1.23
1.41
0.71
3.40
11.40
0.94
1.06
0.76
3.50
Cu
O.S5"
0.53
13.30
1.37
1.13
1.17
2.80
2.50
5.90
9.30
1.09
1.23
5.30
1.73
l.CO
0.'92
1.57
4. SO
1.43
1.13
1.31
1.64
11.10
1.47
1.23
1.19
1.92
9.20
1.61
1.53
0.77
1.21
4.00
1.41
1.04
1.09
2.30
»*>
Z.40
0.95
43.50
18.50
6.25
3.45
5.35
9. OS
6.20
6.05
4.C5"-
3.00
62. CO
13.55
6.20
3.96
4.65
4S.50
11.15
6. 25
3.55
2. SO
13. =0
7.80
S.5S
4.10
5.30
27.00
10.35
4.15
2.25
3.C5
17.00
12.10
7.tO
4.50
4.45
F*
3.5
2.2
23. S
s.i
5.6
4.0
5.7
7.1
4.9
3.fc
2.8
3.Z
16.1
7.7
0.1
4.1
4.7
It. 3
6.1
6.3
6.7
7.1
13.9
7.1
5.6
4.1
6.7
16.3
6.7
5.1
3.3
4.3
U.I
6.8
S.7
4.5"
5.7

-------
         Table 30-continued
en
Site no.
6A
68
6C
ICA
KB
KC
7A
7C
Soil
depth
Inches
0
6
li
24
0
6
It
24
0
6
12
24
0
6
12
14
0
6
12
24
0
6
12
24
0
6
1
-------
           Table 30-continued

SUe no.
7C
Soil
depth
Inches
24 - 36
0-6
6-12
12 - 24
24 - 36
36+
PH
saturated
paste
9.5
8.3
8.4
8. S
8.8
9.0
Cond.
«nhos/cmz
0.13
0.55
0.31
0.07
0.08
0.07
TKN
X
0.02
0.19
0.05
0.02
0.03
0.03

N03-N
1
63
3
1
1
1

NaHCOa
P
2
170
24
2
1
2

t»<4-Ac
K
50
158
64
56
56
39

NK4-N
7
41
24
4
4
7
rro/ko
Cl
saturated
pzste
2.1
2.1
2.1
2.1
2.1
2.1


In
0.22
20.00
2.19
0.42
0.47
0.93


Cu
0.09
12.10
0.99
0.19
0.32
0.20

CTPA
Mn
1.6S
23.50
7.20
4.75
1.65
1.10


Fe
3.9
36. 5
16.6
13.6
9.7
6.9
cr>
              1SS - insufficient sanple for analysis

-------
Table 31-Analysis of Lowry Bombing Range soils sampled  spring of 1974

«!9/k9
Soil P« Cl
depth saturated ConU. , TKN KaHCOa NH4-AC saturated
Site no. Inches paste «»hos/cmz % N03-N P 1C NH4-H paste

P7PA
In Ca Mo ft
1A



IB



1C



2A



2U



K



3A



ib



3C



4A

0 -
6 -
12 -
24 -
0 -
6 -
12 -
24 -
0 -
6 -
12 -
24 -
0 -
6 -
12 -
24 -
0 -
6 -
I* -
24 -
0 -
6 -
12 -
24 -
0 -
6 -
12 -
24 -
0 -
6 -
12 -
24 -
0 -
6 -
12 -
24 -
0 -
6 -
6
1Z
24
36
6
12
24
36
6
12
24
36
6
12
14
36
6
12
24
35
6
12
24
36
6
12
24
36
6
12
24
36
6
12
24
36
6
12
7.0
7.4
7.9
7.8
7.4
7.7
7.3
7.7
7.3
7.7
7.8
7.3
7.3
7.3
7.7
ft.o
7.2
6.9
7.7
6.2
6.3
7.1
8.0
8.?
6.4
7.5
8.2
8.1
7.8
7.7
7.7
7.7
7.6
ISS
8.0
7.9
7.t>
7.6
0.9
0.5
0.4
0.7
0.7
0.6
1.8
7.6
1.5
0.6
0.4
0.6
1.2
0.6
0.5
0.6
1.1
0.6
0.6
1.0
0.6
0.7
2.9
C.2
7.)
2.7
2.7
7.1
7.1
3.4
3.3
4.7
9.9
ISS
3.1
tt.2
».
6.5
3.7
41.0
13.7
9.3
6.3
5.4
5.6
4.6
6.4
6.0
4.1
5.7
5.3
5.1
4.3
22.1
6.6
6.6
5.5
34.3
15.2
9.2
5.5
34.0
14.0
5.9
4.0
4S.5
19.6
6.2
9.1
35.$
18.7
15.2
6.9
41. fc
30.0
7.5
6.4
24.1
7.1

-------
        Table 31-continued
Site no.


48



4C



5A



SO



sc



6ft



68



6C



7A
4"


Soil
depth
Incites
12 -
24 -
0 -
6 -
1? -
24 -
0 -
6 -
12 -
24 -
0 -
6 -
72 -
24 -
'0 -
6 -
12 -
24 -
0 -
6 -
12 -
24 -
0 -
6 -
12 -
24 -
0 -
6 -
12 -
24 -
0 -
6 -
12 -
24 -
0 -
6 -
12 -
24 -
24
36
6
12
24
36
6
12
24
36
6
12
24
36
6
12
24
36
6
12
24
36
6
12
24
36
6
11
24
36
6
12
24
36
6
If
24
36
pH
saturated
paste
8.1
8.2
7.2
6.7
7.8
1.7
7.4
7.0
7.7
7.9
7.4
7.3
7.7
7.9
7.5
7.7
7.9
7.9
7.5
7.2
7.5
7.8
7.4
8.0
8.1
8.1
7.2
7.6
7.6
7.9
7.3
7.5
7.7
7.6
7.3
7.6
7.5
7.6
Cond.
mhos/cm*
2.4
2.1
7.6
4.7
1.7
4.6
6.5
3.6
3.7
4.9
1.3
1.4
1.6
2.6
3.2
2.6
2.2
1.9
3.C
2.8
1.3
3.1
5.5
2.8
5.5
16.5
1.0
1.0
1.0
0.9
7.6
3.3
1.8
4.3
4.0
4.3
5.5
s.a
TKH
X
0.07
0.04
0.31
0.10
0.06
0.04
0.38
0.12
0.07
0.07
0.29
0.10
0.06
0.04
0.21
0.08
0.06
0.05
0.31
0.13
0.05
0.03
0.34
0.06
0.04
0.03
0.11
0.07
0.04
0.02
0.41
0.07
•0.03
0.03
0.12
0.15
0.1U
0.35

K03-N
55
45
330
190
36
31
340
150
87
83
81
30
44
64
190
93
6U
33
240
91
14
23
160
47
10
2
2
0
0
0
500
340
21
22
87
34
2
1

NaHC03
P
5
9
275
21
8
15
380
42
10
13
290
16
8
10
175
6
5
8
385
65
15
17
290
17
14
13
60
2
2
5
350
16
10
24
175
165
155
130

NH«-Ac
K
200
191
378
465
265
175
393
650
308
235
450
388
240
183
473
243
194
205
358
438
240
205
303
188
133
159
308
188
145
123
299
158
115
73
183
175
195
145

NIU-N
5
4
9
S
4
4
7
8
8
7
11
7
5
6
13
8
8
7
12
17
6
5
9
6
6
6
7
S
B
7
14
6
7
7
23
41
112
122
as/kg
tl
saturated
paste
200.0
225,0
550.0
340.0
140.0
240.0
420.0
310.0
375.0
740.0
20.0
80.0
100.0
255.0
160.0
1GO.O
190.0
188.0
140.0
80.0
70.0
1SO.O
.440.0
325.0
75*0.0
1840.0
44.0
130.0
136.0
75.0
420.0
270.0
260.0
210.0
420.0
140.0
212.0
200.0




OT?A
In
0.43
0.96
35.0
1.17
0.38
O.S2
41.5
2.00
36.5
4.60
0.63
0.62
60.0
2.40
17.8
0.99
4.20
0.32
0.95
1.51
41.0
1.93
0.51
0.95*
19.0
0.66
0.57
0.61
0.16
0.13
79.0
1.96
1.00
3.40
27.0
21.5
22.5
17.5
Cu
1.3?
1.4l
14.20
2.00
1.31
1.24
15.35
2.60
19.40
4.90
1.2i
1.02.
28.20
Z.2S>-
i.&ii
i,i&
4.90
1.34
1.47
1.56
28.00
2.52
1.30
1.52
8.30
1.06
1.1&
1.24
0.96
0.64
36.6
2.08
0.75
1.C8
1.87
12.90
7.90
6.30
m
6.6
5.4
101.0
43.0
7.1
4.7
51.0
41.5
30.0
27.5
5.3
5.9
29.0
0.8
5.0
2.9
17.0
8.0
8.5
6.7
25.0
15.0
6.6
4.4
12.6
7.2
5.5
3.6
3.9
3.7
37.0
7.1
4.0
3.9
39.5
66.0
107.0
1*4.0
ft
5.4
5.2
35.0
23.5
6.7
5.5
37.2
17.9
31.5
26.2
8.0
5.4
43.0
13.9
7.8
6.3
M. S
8.7
tt.2
8.7
37.1
12.7
7.2
6.9
20.3
7.1
6.4
4.9
6.3
5.0
2S.5
8.7
6.4
7.0
40.0
49.f
29.ff
24 .2.
o>

-------
Table 31-continued
Soil
depth
Site no. Inches
76 0-6
6-12
12 - 24
24-36
« 0
f
12
24
n» o
6
1C
6
12
24
36
5
12
24
24-36
PH
uturated
paste
7.7
7.6
7.6
7.8
7.5
7.4
8.0
7.7
7.i
7.3
7.0
7.0
Cond.
mtus/af
3.8
3.7
3.8
4.3
9.0
9.7
8.2
7.7
4.0
4.4
7.7
6.7
?
0.04
0.05
0.07
0.06
0.14
0.12
0.11
0.14
0.17
0.08
0.02
0.02

NQ3-N
10
18
17
7
180
240
3
24
60
170
310
220

IUHCOJ
P
10
23
60
22
230
125
130
170
400
276
SO
48

NH4-AC
K
153
183
93
68
243
193
170
260
250
170
133
140

NH4-H
10
9
22
32
13
38
160
146
15
12
10
9
,*/„„
CJ
saturated
piste
65.0
90.0
10.0
135.0
133.0
1179.0
75.0
762.0
356.0
269.0
490.0
415.0


in
1.18
3.50
12.50
3.40
21.0
26.0

16.5
40. S
26.5
5.2
3.7

91
CM
1.04
1.77
4. tO
l.SO
8.80
14.95
0.70
7.50
11.20
7.4b
3.M
4.50

i*
Mo
4.8
5.9
14.8
25.0
10.0
£.9
33.0
55.5
9.4
5.9
10.7
4.2


f*
6.6
10.7
19.8
24.2
26.7
41. y
34.6
40.5
32.0
2J.6
1S.5-
16.0

-------
        Table 32-Analysis of Lowry Bombing Range soils sampled fall of  1974
Soil pH
depth saturated Co
Cite no. Inches paste mho
mq/Vq
	 Cl
ml. TKN N»HC03 NHfl-Ac saturated , OT?A
s/enz J N03-N P K NH4-H paste Zn Cu nn te
ot>
o
1A



18



1C



ZA



23



K



3A



3B



3C



4A

0 - 6
6-12
U - 24
24-36
0-6
6-12
ia - 24
24 - 36
0 - 6
6-1?
12 - 24
Z4 - 36
0 - 6
6-12
12 - 24
24 - 36
0-6
6 - 12
12 - 24
24 - 36
0 - 6
6 - 12
12 - 24
24 - 36
0 - 6
6 - 12
12 - 24
24 - 36
0 - 6
6-12
12 - 24
24 - 36
0-6
6 - 12
12 - 24
24 - 36
0-6
6-12
7.5
7.8
8.0
8.0
7.6
7.8
7.9
7.7
7.1
8.2
8.1
8.1
7.5
7.5
e.o
6.3
7.3
7.b
8.1
8.3
6.5
6.9
8.1
7.8
7.1
7.1
7.6
7.7
6.4
6.9
7.5
7.7
7.7
7.9
8.0
6.0
7.1
7.0
0.6
0.4
0.4
0.7
0.5
0.5
0.9
5.2
1.1
1.7
6.5
8.7
1.2
0.7
0.5
0.8
0.9
0.5
0,5
1.0
8.7
1.6
0.9
4.0
8.7
3.7
2.6
4.7
9,2
4.4
2.0
1.9
1.7
1.0
0.6
0.8
0.9
3.9
0.116
0.091
0.041
0.029
0.159
0.079
0.032
0.028
0.070
0.066
0.043
0.024
0.174
0.081
0.056
0.033
0.150
0.075
0.045
0.027
0.197
0.088
0.057
0.038
0.292
ISS
0.058
0.043
0.238
0-.103
0.064
0.063
0.243
0.21*
0.091
0.060
0.219
0.097











13
2
1
2
5
6
2
1
1
43J
75
6
3
570
155
66
42
600
275
67
33
400
300
94
28
220
270
22
2
1
4
4
1
1
2
17
4
10
11
80
12
12
12
72
5
2
6
120
14
5
17
385
43
4
15
325
14
4
11
225
225
53
21
165
8
393
240
220
235
325
220
210
205
26S
338
225
235
650
5oO
273
230
393
255
398
220
405
580
430
273
40S
700
630
500
1030
5BO
425
245
700
500
650
530
418
700
21
12
10
7
14
10
S
15
14
13
17
!i
12
11
9
10
10
13
5
7
47
17
9
11
32
I5S
10
7
30
18
9
7
19
27
13
13
19
29
<2
<2
<2
<2
5
<2
2
2
10
6
22
22
2
't
<2
2
<2
2
2
10
10
2
2
2
2
14
15
15
20
12
8
8
10
12
12
5
5
'25-
0.6
0.2
0.2
0.2
0.6
0.2
0.2
Q.c
0.6
0.3
0.2
0.2
10.5
1.0
0.5
0.6
6.3
0.3
0.2
0.2
19.0
0.7
0.3
0.2
41.5
2.8
2.1
0.3
33.0
0.6
0.4
3.0
16.0
15.5
1.3
0.4
26.0
1.2
0.7
0.7
0.7
0.7
0.6
0.7
0.6
0.7
0.7
1.0
0.7
0.7
5.4
1.2
0.9
0:7
5.7
0.9
0.7
0.6
5.9
1.2
0.8
0.8
17. a
1.9
0.9
1.1
12.6
1.5
1.1
2.7
12.5
1.6
0.9
0.7
12.0
1.6
13.7
7.4
4.2
3.2
6.9
5.2
2.6
3.2
13.2
6.7
4.1
1.7
17.0
14.0
4.6
2.4
15.0
7.6
4.6
3.6
34.0
20.0
6.7
3.1
18.5
14.0
G.6
3.5
98.0
25.0
7.8
2S.5
99.0
44.0
20.0
8.0
60.0
23. S
8.9
4.9
7.0
7.6
6.0
S.S
7.1
6.3
15,2
10.3
5.4
5,9
20.2
9.6
10. b
10.2
24.4
9.9
8.9
7.7
64.5
26.fi
10.9
6.4
59.0
21.3
9.3
7.3
25.7
U.9
r.7
9.7
63.0
47.0
17.4
6.3
65.0
21.0

-------
         Table 32-continued
00


S*t« BO.


48



4C



5A


n



St


6A



63



7C


70




Soil
depth
Inches
1? - 24
24 - 36
0-6
6 - 12
12 - 24
24 - 36
0-6
6 - 1?
12 - 24
24 - 36
0-6
6 - 12
12 - 24
24 - 36
0-6
6 - It
12 - 24
24 - 36
0-6
6-12
12 - 24
24-36
0-6
6-17
12 - 24
24 - 36
0-6
6-12
12 - 24
24 - 36
0-6
6-12
12 - 24
24 - 36
0-6
6-12
12-24
24 - 3<

PH
saturated
paste
3.1
8.0
7.3
7.9
8.1
8.5
7.5
7.8
b.4
8.4
7.S
8.0
8.3
8.4
7.8
li.b'
n.3
8.1
7.0
7.4
8.0
8.1
7.5
7.8
8.2
8.5
7.9
8.2
8.3
8.1
7.6
7.C
7.9
9.1
7.6
7.5"
7.4
7.5

Cond.
nnhos/cn2
2.4
4.6
2.8
2.0
1.7
1.6
6.8
3.0
1.3
1.7
8.5
4.2
2.0
3.0
4.1
2.0
2.0
5.7
15.4
.1
.4
. 7
.8
.6
.0
2.2
1.4
8.7
2.5
11.0
7.1
1.7
0.9
1.1
4.1
6.2
6.2
4.1

TfN
1
0.056
0.033
0.162
0.096
0.051
0.034
0.280
0.089
0.054
0.034
0.341
0.106
O.ObO
0.035
0.297
0.076
0.039
0.030
0.520
1SS
0.047
0.03*
0.136
0.064
0.036
0.026
0.145
0.029
0.052
0.022
1SS
0.080
0.036
0.023
O.iOO
o.oai
0.065
0.076


H03-N
64
3
160
86
42
25
330
94
81
34
6CO
290
130
51
380
160
65
61
1000
250
32
21
46
23
2
1
32
16
42
2
210
29
1U
6
120
220
190
82

NeHCOj
P
3
H
115
7
4
7
440
21
10
11
450
44
15
13
345
14
5
11
450
30
7
7
125
4
5
7
175
12
8
10
170
10
1
1
650
34
7
90

NH4-Ae
K
393
265
405
283
278
290
580
255
225
193
363
245
210
200
363
308
273
295
430
375
250
2bB
425
2<5
205
178
342
230
220
250
490
245
250
240
550
283
260
295


NH4-N
23
19
23
17
16
21
9
10
5
9
32
35
16
19
22
22
14
19
11
20
14
14
20
16
18
15
20
15
22
15
1SS
44
19
16
66
41
20
20
irg/kg
Cl
saturated
paste
10
20
8
12
10
8
25
12
22
22
45
22
12
8
25
10
8
5
40
IB
2
2
a
12
5
8
5
25
18
25
32
6
2
5
25
45
38
25


**
0.3
0.2
li.5
0.3
0.2
0.2
56.0
1.0
0.6
0.6
68.0
3.7
0.9
0.5
45.0
0.6
0.3
0.5
85.0
4.0
0.2
0.3
10.2
0.2
0.3
0.2
15.2
0.2
0.3
0.3
12.0
0.6
0.1
0.2
66.0
1.3
0.4
6.5

DT
Cu
1.1
1.0
7.4
O.S
0.9
0.9
35.0
1.5
1.1
1.1
10.0
2,3
1.2
1.0
42.0
U4
1.0
1.3
4.0
3.2
0.9
O.S
6.8
0.9
0.8
0.8
9.6
0.9
1.0
0.9
2.0
0.9
0.7
0.7
32.4
1.9
1.4
3.9

PA
Mn
5.4
11.0
15.0
7.4
6.3
5.0
31.0
9.2
5.4
4.2
26.0
7.7
5.1
4.7
26.0
9.1
1.4
4.1
ba.O
lb.0
3.0
4.4
8.5
5.7
4.0
3.4
10.0
3.3
5.6
2.8
26.0
7.4
4.7
4.0
26.0
26.0
7.1
7.9


fe
11.7
7.3
30. i
9.0
9.0
7.b
67.0
12.0
9.4
o.4
72.0
14. (5
5.9
6.4
71.0
12.1
11. Z
9.3
Cf^
•0
20.9
9.7
7f
.4
Zl.6
9.9
7.9
7.1
17.B
7.9
10.0
6.4
23.1
9.3
9.4
9.4
9.6
12.2
11.1
U.I

-------
          Table 32-contlnued
SUt no.
KA
KB.
Soil
depth
Inches
0
6
12
24
0
6
12
24
- 6
- 12
- 24
- 36
- 6
- 1*
- 24
- 36
PH
saturated
paste
7.4
7.5
7.7
7.9
7.4
l,t
7.3
7.8
Cond.
.mhos/cor
5.5
5.4
6.2
6.2
S.8
7.4
6.9
5.3
TKN
S
0.157
0.144
0.123
0.176
0.242
O.lOb
0.124
0.129

N03-N
29
42
9
1
130
220
160
2

N»HC03
135
125
115
125
400
100
95
85

NH4-AC
K
170
170
173
193
260
175
165
125

»H4-N
360
ISS
165
ISS
36
44
240
600
_^ MC/kd
Cl
saturated
paste
62
52
38
18
32
30
33
48




DTfA
in
16.9
16.1
10.2
14.0
43.0
18.5
22.0
26.0
Cu
8.4
7.0
6.8
6.9
19.0
9.6
12. if
9.0
Mn
SZ.O
85.0
99.0
81.0
8.8
39.0
S4.C
36.0
Ft
9.9
9.7
6.9
10.7
53.0
70.0.
Ss.O
37. «.
00
ro
             ISS • Insufficient, staple for

-------
                                REFERENCES
1.  Soil Conservation Service, 1971.  Soil Survey Arapahoe County, Colorado,
    United States Department of Agriculture.

2.  Soil Conservation Service, 1974.  Soil Survey Adams County, Colorado,
    United States Department of Agriculture.

3.  Jackson, M.L., 1958.  Soil  Chemical Analysis.  Prentice Hall, Inc.,
    Englewood Cliffs, New Jersey.

4.  Watanabe, F.S. and S.R. Olsen, 1965.  Test of an Ascorbic Acid Method
    for Determining Phosphorus in Water and NaHCOS Extracts from Soil.   Soil
    Science Soc. Amer. Proc. 29:677-678.

5.  Pratt, P.P., 1965.  Potassium.  In C.A. Black (ed.) Methods of Soil
    Analysis, Part 2-Chemical and Microbiological Properties, Chapter 71,
    p. 1026.

6.  Lindsay, W.L. and W.A. Norvell, 1969.   Development of a DTPA Micronutrient
    Soil  Test, Agron. Abstr.
                                     83

-------
                                   GLOSSARY
B
Ca
Cd
CEC
Cl
cm
COD
CSU
Cu
DTPA
FDI
Fe
Fed 3
9
ha
K
kg
LBR
Metro

Mg
MGD
umho/cm
mmho/cm.
Mn
Mo
N
Na
NCRDC
NHt
NH-f-N
NO,
N03-N
OM
P
Pb
PH

ppm
TKN
TS
Zn
boron
calcium
cadmium
cation exchange capacity
chlorine
centimeters
chemical oxygen demand
Colorado State University
copper
di ethylenetriamenepentaacedi c aci d
flash dryer-incinerator
iron
ferric chloride
grams
hectare
potassium
kilograms
Lowry Bombing Range
Metropolitan Denver Sewage Disposal
 District No. 1
magnesium
million gallons per day
micro mho per square centimeter
mi Hi mho per square centimeter
manganese
molybdenum
nitrogen
sodium
Northern Colorado Research & Demonstration
ammonia
ammonium
ammonium nitrogen
nitrate
nitrate nitrogen
organic matter
phosphorus
lead
negative logarithm of the hydrogen
  ion  activity
parts  per million
total  Kjeldahl nitrogen
total  solids
zinc
Ctr.
                                      84

-------
                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
1. REPORT NO.

  EPA-600/2-77-054
             3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
  COMPREHENSIVE SUMMARY OF SLUDGE DISPOSAL RECYCLING
  HISTORY
             6. REPORT DATE
               April  1977  (Issuing Date)
             S. PERFORMING ORGANIZATION CODE
7, AUTHOR(S)
  John  C.  Baxter,  William J. Martin, Burns R. Sabey,
  William  E.  Hart, David B. Cohen, and Carl  F. Calkins
             8. PERFORMING ORGANIZATION REPORT NO,
9. PERFORMING ORGANIZATION NAME AND ADDRESS
  Metropolitan Denver Sewage  Disposal  District No. 1
  3100  East 60th Avenue
  Commerce City, Colorado 80022
             10. PROGRAM ELEMENT NO.

               1BC6H
             11. CONTRACT/GRANT NO.

               68-03-2064
12. SPONSORING AGENCY NAME AND ADDRESS
  Municipal  Environmental Research Laboratory—Gin. ,OH
  Office  of  Research and Development
  U.S.  Environmental Protection Agency
  Cincinnati,  Ohio   45268
             13. TYPE OF REPORT AND PERIOD COVERED
               Final   1967-1974	
             14. SPONSORING AGENCY CODE
               EPA/600/14
16. SUPPLEMENTARY NOTES
16>A^inceT1971  the only mode of sludge disposal used  by  Metro  has been land application.
 A number of  different application procedures have been  tried  over the intervening
 years.  The  development of methodology and problems  associated with each procedure
 are discussed  in  the text.
    Continuous  applications of sludge to the soil at  the Lowry Bombing Range since 1969
 have raised  the concentration of nutrients, metals,  salts  and organic matter.  The
 effects of these  excessive loading rates on the  soil, crops and environment are evalu-
 ated.
    The effects of various sludge applications to soil on germination, emergence, sub-
 sequent plant  growth, and uptake of heavy metals are examined.  Inhibition of germin-
 ation decreased with increasing soil sludge incubation  periods or when dried sludge
 was used, suggesting that salts or some volatile component within the sludge was in-
 hibiting germination.
    Microbial counts of fecal coliform bacteria in sludged  plots showed no appreciable
 differences  from  control plots after a 6 month incubation  period.
    Liquid sludge  added to shallow earthen drying basins demonstrated that water is
 lost through soil  percolation in addition to evaporation,  and that about half the N
 content of sludge is lost.   A discussion of future research needs is 
-------