United States
Environmental Protection
Agency
Municipal Environmental
Research Laboratory
Cincinnati, OH 45268
Research and Development
EPA-600/S2-84-035 Mar 1984
&ERA Project Summary
Strip Mine Reclamation with
Municipal Sludge
William E. Sopper and Eileen M. Seaker
Treated municipal sludge was used to
revegetate three 4-ha demonstration
plots in the anthracite and bituminous
coal mining regions of Pennsylvania.
The three sites selected represented
more than 100,000 ha of abandoned,
barren bituminous strip mine spoil
banks and anthracite refuse banks
present in the state.
Various types of sludges (liquid
digested, dewatered, and composted)
were applied at different application
rates to supply the necessary nutrient
pool for establishing vegetation and to
adhere to state guidelines regarding
lifetime applications of trace metals on
the land. Following sludge application
and incorporation, all sites were seeded
with a mixture of grasses and legumes.
A monitoring system was installed at
each demonstration plot to determine
the effects of the sludge applications on
(1) the bacteriological and chemical
qualities of soil percolate and ground-
water, (2) soil chemical properties, and
(3) the growth and quality of the
vegetative cover.
Data collected over a 5-year period
indicate that the sludge applications
ameliorated the adverse site conditions
and resulted in a quick, complete
vegetative cover that has persisted and
improved each year. No deterioration
in vegetation yield or quality has been
observed on any site. Although sludge
applications increased some trace
metal concentrations in the vegetation,
all concentrations were below plant
tolerance levels, and no phytotoxicity
symptoms were ever observed. Before
vegetation was established, the sludge
applications caused some sporadic,
short-lived increases in nitrate-nitrogen
concentrations in soil percolate water.
However, in general, the sludge appli-
cations had no significant adverse
effects on the chemical or bacteriological
quality of groundwater.
Study results indicate that stabilized
municipal sludges can be used to
revegetate mined lands in an environ-
mentally safe manner with no adverse
effects on the vegetation, soil, or ground-
water quality. The study also shows
that at the proper rates, single applica-
tions of sludge on a mined site can
successfully establish vegetation and
sustain it for the 5-year period mandated
under the Federal Surface Mining
Control and Reclamation Act of 1977.
This Project Summary was developed
by EPA's Municipal Environmental
Research Laboratory, Cincinnati. OH.
to announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information ttt
back).
Introduction
Millions of acres of barren land
disturbed by mining activities exist
throughout the United States. Much of
this land is a source of acid mine
drainage, surface runoff, erosion, and
sedimentation, all of which have created
serious water pollution and land degrada-
tion problems. In the United States,
surface mining alone has disturbed 1.76
x 106 ha (6,700 miles2); half of that land
was disturbed specifically by coal mining
(Schaller and Sutton, 1978). Each year,
coal mining will disturb an additional
40,470 ha, much of which will be in the
populated eastern half of the United
States. Paone et al. (1978) have projected
that the amount of land that will be used
-------
by the surface coal mining industry will
increase from 25,000 ha in 1977 to
47,000 ha in 1990.
Drastically disturbed lands generally
provide a harsh environment for establish-
ing vegetation. Major deterrents to
vegetation establishment are usually a
lack of nutrients and organic matter, low
pH, low water-holding capacity, toxic
levels of trace metals, compaction, and
poor physical condition of the spoil.
The new Federal Surface Mining
Control and Reclamation Act of 1977
established strict regulations for the
revegetation of currently mined land
(Federal Register, 1982). In general, the
law requires establishment of a diverse,
effective, and permanent vegetative
cover of the seasonal variety native to the
affected area of land. Furthermore, the
cover must be capable of self-regeneration
and plant succession at least equal in
extent of cover to the natural vegetation
of the area. The Office of Surface Mining
Reclamation and Enforcement (OSM),
which was established under the law,
has recommended performance standards
for meeting the revegetation requirements.
These recommendations are as follows:
1. The permanent vegetative cover of
the area must be at least equal in
extent of cover to the natural
vegetation of the area and must
achieve productivity levels compatible
with the approved postmining land
use. Both native and introduced
vegetation species may be used.
2. The period of responsibility begins
after the last year of augmented
seeding, fertilizing, irrigation or
other work that ensures revegetation
success.
3. In areas of more than 66 cm of annual
precipitation, the period of extended
responsibility will continue for not
less than 5 years. In areas with 66
cm of precipitation or less, the
period of responsibility will continue
for not less than 10 years.
4. Normal husbandry practices essential
for plant establishment will be
permitted during the period of
responsibility so long as they can
reasonably be expected to continue
after bond release.
5. In areas of more than 66 cm of
precipitation, the vegetative cover
must be equal to the success
standard only during the growing
season of the last year of the
responsibility period (or during the
last 2 years if required by the
regulatory authority). In areas with
less than 66 cm, the vegetative
cover must be equal to the success
standard for the last 2 years of the
responsibility period.
6. The ground cover, productivity, or
tree stocking of the revegetated area
shall be considered equal to the
success standard approved by the
regulatory authority when the param-
eters are fully equivalent with 90
percent statistical confidence.
In addition to these Federal requirements,
individual states will be developing their
own regulations defining revegetation
performance standards as they are
granted primacy by OSM.
Also to be followed are the already
existing state and Federal guidelines
and regulations related to the land
application of sludge (U.S. Environmental
Protection Agency, 1977, and Pennsylvania
Department of Environmental Resources,
1977). Most of these guidelines limit
sludge application rates based on nitrogen
and other plant nutrient requirements of
the vegetation as well as trace metal
loadings.
Bastian et al. (1982) have reported that
more than 4.2 million dry tons of treated
and processed sludge are produced
annually. About 42 percent is applied to
the land as a soil amendment or fertilizer,
and the remainder is incinerated (27%),
landfilled (15%), stored in lagoons (12%),
or diposed of in the ocean (4%) (Felicia-
no, 1982).
Considerable research has been con-
ducted during the past decade showing
that stabilized municipal sludge from
secondary wastewater treatment plants
is an excellent soil amendent and
fertilizer. But even though a sound
technical base exists to support the use of
sludge for land reclamation, the public
has been reluctant to accept the concept.
To bridge this gap between available
technical information and public under-
standing, a cooperative project was
initiated in 1977 to establish several 4-ha
plots in the anthracite and bituminous
coal mining regions of Pennsylvania and
to demonstrate that sludge can be used
for revegetating mined land in an
environmentally acceptable manner.
The present study continues the 1977
project. The initial grant from the U.S.
Environmental Protection Agency (EPA)
was used to establish three 4-ha demon-
stration plots in the anthracite and
bituminous coal mining regions of
Pennsylvania. The three stites were
representative of abandoned, barren
bituminous and anthracite mines. All were
treated with various types of municipal
sludges at various application rates and
broadcast seeded with a mixture of
grasses and legumes. A monitoring 4
system was installed at each demonstra- ^
tion site to determine the effects of the
sludge application on (1) the chemical
and bacteriological quality of groundwa-
ter and soil percolate water, (2) the
chemical properties of the soil, and (3) the
quality and growth of the vegetative
cover. Data collected during the first 3-
year period were reported in the final
report of the initial grant. These results,
as well as detailed information on each
demonstration site, are available in the
complete report (NTIS Order No. PB 82-
102484) entitled "Revegetating Strip-Mined
Land with Municipal Sewage Sludge"
(Sopper and Kerr, 1980, 1981).
The purpose of the present project was
to continue to collect samples from the
existing monitoring system at each
demonstration site. The broad objectives
were threefold: (1) to demonstrate that
municipal sludge could be used in an
environmentally acceptable manner to
revegetate lands disturbed by mining
activities, (2) to reduce erosion and
stream siltation, and (3) to reclaim land
damaged by mining activities so that it
could be returned to agricultural uses.
The Pennsylvania Department of
Environmental Resources (PDER) current-
ly requires monitoring for 2 years after M
land application of sludge. The revegeta- ™
tion regulations developed by the Federal
Office of Surface Mining Reclamation
and Enforcement require a 5-year period
of responsibility for vegetation establish-
ment and regeneration in areas with
more than 66 cm of precipitation. The first
demonstration plot in Venango County
was established in May 1977. This
project monitored the plot through five
growing seasons (1977-1981). The other
two demonstration plots in Westmoreland
and Lackawanna Counties were monitored
for 2 and 4 years, respectively.
Venango County
This site represented bituminous strip
mine banks that were backfilled and
recontoured after mining without top soil re-
placement. Several unsuccessful attempts
had been made earlier to revegetate the
area using lime, commercial fertilizer,
and seed. The surface spoil was compact-
ed, extremely acid (pH 3.8), and devoid of
vegetation. A 4-ha demonstration plot
was established. The plot was scarified
with a chisel plow to loosen the surface
spoil material and then treated with
agricultural lime (4.5 to 12.3 mt/ha) to
raise the spoil pH to 7.0. •
-------
Sludge for the project was obtained
from three local waste treatment plants.
Liquid digested sludge from the cities of
Farrell and Oil City was transported to
the site in tank trucks. Dewatered sludge
came from Franklin (where the sludge is
dewatered by centrifuging) and from Oil
City (where the sludge is dewatered by
spreading on sand drying beds). The
dewatered sludge was brought to the site
in coal trucks.
The 4-ha plot was subdivided into four
1-ha subplots for application of liquid
digested sludge at two rates and dewatered
sludge at two rates. Liquid digested
sludge was applied with a vacuum tank
liquid manure spreader at 7 mt/ha (103
mvha) and at 11 mt/ha (155 mVha).
Dewatered sludge was applied at 90 and
184 mt/ha.
Procedures
Immediately after sludge application
and incorporation, the site was broadcast
seeded with a mixture of two grasses and
two legumes. The seeding mixture was
Kentucky-31 tall fescue (22 kg/ha),
Pennlate orchardgrass (22 kg/ha), Penn-
gift crownvetch (11 kg/ha), and Empire
birdsfoot trefoil (11 kg/ha). The site was
mulched with straw and hay at the rate of
3.8 mt/ha. The levels of trace metals
delivered even at the highest sludge
application rate were well below the
recommended Federal and state lifetime
limits, except for copper, which slightly
exceeded the Pennsylvania guidelines
(Table 1).
The nutrients supplied at each of the
sludge application rates are listed in
Tabie 2. Potassium is the only nutrient
deficient at all sludge application rates.
Commercial fertilizer equivalents are also
given in Table 2. The highest sludge
application rate (184 mt/ha) was equiva-
lent to applying an 11-9-0 commercial
chemical fertilizer at 22 mt/ha. One of
the principal advantages of using sludge
is that it is a slow-release fertilizer and
will supply plant nutrients for 3 to 5 years.
Most of the nitrogen is in the organic form
and therefore not immediately available
for plant use until it is mineralized and
converted to available plant forms. Only
about 20 percent of the organic nitrogen
is mineralized in the first year, and 5 to 10
percent of the remaining organic nitrogen
is released the second year. Decreasing
amounts of organic nitrogen are released
with each subsequent year. Afterthefirst
3 to 5 years, the natural process of
nutrient recycling should be well established
for sustaining the vegetation.
Results
All sludge-treated areas had a complete
vegetative cover within 3 months after
application. Vegetation height and dry
matter production were measured at the
end of each growing season during the
period 1977-81. Both measurements
tended to increase over the first 4 years
and then stabilize. Dry matter production
includes all above-ground organic matter
(green crop and organic litter accumula-
tion). No crops were harvested over the 5-
year period.
During the first 2 years, the two grass
species were the dominant vegetation
type on all sludge-treated plots. By the
third growing season (1979), the two
legume species were well developed and
had become the predominant vegetative
cover (Figure 1).
Table 1.
Comparison of State and Federal Recommendations with Venango County Trace
Metal Loadings at the Highest Application Rates of Liquid and Dewatered Sludge
Trace Metal Loadings
(kg/ha) at Two Sludge
Application Rates
Recommended Maximum
Loadings (kg/ha)
Constituent
Cu
In
Cd
Pb
Ni
Cr
Hg
11
mt/ha
21
21
0.1
10
1
16
0.01
184
mt/ha
129
147
0.6
55
12
74
0.09
EPA*
(CEC5-15)
280
560
11
1.120
280
NRt
NRt
poem
112
224
3
112
22
112
0.6
* Average CEC of site ranged from 11.6 to 15.2 meq/100 g.
t Pennsylvania Department of Environmental Resources Interim Guidelines.
\ No recommendations given by EPA,
Table 2. Commercial Fertilizer Equivalents of the Sludge Applications at the Venango County
Demonstration Site
Sludge Application
Rate
(mt/ha)
184
90
11
7
Amount
(kg/ha)
22.400
11.200
2.240
2.240
Fertilizer Equivalent (Fertilizer Formula)
N
kg/ha
2.388
1.165
284
187
%
(11)
(10)
(13)
(8)
PzOs
kg/ha
2.103
1.026
143
95
%
(9)
(9)
(6)
(4)
*
KsQ
kg/ha
21
11
6
2
%
(0)
(0)
(0)
(0)
* For example, 184 mt sludge/ha is equivalent to 11-9-0 fertilizer at 22.400 kg/ha.
Figure 1. Venango County site 5 years after sludge application. Note that the two legume
species have replaced the grass species as the predominant permanent cover.
-------
Samples of the individual grass and
legume species were collected at the end
of each growing season for foliar analyses.
Results for tall fescue grown at the
highest sludge application rate and with
no sludge (the control plot) appear in
Table 3. Many trace metal concentrations
were higher in the tall fescue growing on
the control portion of the site. This result
was probably due to spoil pH at the 0- to
15-cm depth, which averaged 3.8 on the con-
trol area and ranged from 5.7 to 7.8 on the
sludge-treated areas. Foliar trace metal
concentrations generally decreased over
the 5-year period, and overall, they were
well below the suggested plant tolerance
levels. No phytotoxicity symptoms were
observed.
Spoil samples were collected annually
to evaluate the effects of the lime and
sludge on spoil pH. After 4 months, spoil
pH (at the 0" to 15-cm depth) increased
from an average of 3.8 and 6.9. Spoil pH
remained at a high level and still
averaged 7.0 (6.1 to 8.0) on the sludge-
treated plots at the end of 5 years.
Spoil samples were also analyzed for
trace metals. Extractable trace metal
concentrations at the 0- to 15-cm depth
generally increased over the 5-year
period. However, the increases were
minimal, and all fall within the normal
range for soils in the United States.
Groundwater samples were collected
monthly from monitoring wells to evaluate
the effects of the sludge application on
water quality (Table 4). Well No. 2 is
within the zone of influence of the sludge
treatments. The water table fluctuated
between 2.6 and 3.4 m. Results indicate
that the highest sludge application (184
mt/ha) did not significantly increase the
concentrations of NOa-N in groundwater,
which were well below the EPA maximum
limits for potable water for all months
sampled during the 5-year period. In
addition, the sludge treatments caused
no significant increases in any trace
metal concentrations in groundwater.
Concentrations of Cu, Zn, Co, Cd, and Ni
were within the EPA drinking water
standards. Only Pb and Cr periodically
exceeded the limits for potable water on
both control and sludge-treated areas. No
fecal coliform samples were observed in
any samples over the 5-year period.
Westmoreland County
This site was also an abandoned
bituminous spoil bank and was selected
to test a fall application of sludge (all other
demonstration sites received early summer
sludge application). This demonstration
would evaluate a fall seeding to establish
Table 3. Trace Metals in Tall Fescue Samples Collected from the Control and Highest-Sludge-
Application Plots at the Venango County Demonstration Project
Sludge
Appli-
cation
(mt/ha)
0
184-Lime
Suggested
Tolerance
Levels
Mean Foliar Concentrations (tig/g)
Year
1977
1978
1979
1980
1981
1977
1978
1979
1980
1981
Cu
10.2
5.7
3.3
3.5
6.6
9.4
8.6
9.2
3.5
12.7
150
Zn
23.2
24.9
9.4
17.2
10.0
48.4
44.4
72.5
41.9
34.8
300
Cr
0.9
0.7
11.2
0.7
<0.1
0.8
0.8
0.5
J.I
<0.1
2
Pb
10.9
8.8
1.8
7.6
3.2
4.5
4.5
1.8
3.8
1.9
10
Co
1.5
1.8
0.6
1.6
<0.1
1.5
1.6
0.6
1.8
1.0
5
Ni
3.1
4.8
18.3
4.6
<0.1
9.8
3.7
2.5
7.3
0.7
50
Cd
0.52
0.27
0.06
0.32
0.27
0.20
0.41
0.08
0.73
0.50
3
a vegetative cover and the efficiency of
the cover for controlling the environmental
effects of the sludge application. The site
had been recontoured without topsoil
replacement and had been abandoned for
approximately 10 years.
Procedures
Sludge for the project was obtained
from the city of Philadelphia Water
Pollution Control Plant, which is located
approximately 450 km from the site. The
plant produces a dewatered, centrifuged
sludge that is composted with wood
chips. The composted sludge is then
mixed with equal parts of centrifuged
sludge cake to increase the nutrient value
of the final product (the total nitrogen
content is approximately 0.6 percent for
the composted sludge and 2.0 percent for
the centrifuged sludge cake).
Results of the compost/cake mix
analyses were used to calculate the
amounts of selected nutrients and trace
metals applied. Results indicated that at
the selected application rate of 134
mt/ha, the compost/cake mix supplied
968 kg nitrogen/ha, 1,816 kg phosphate/
ha, and 215 kg potash/ha. The 134
mt/ha application rate would thus supply
nutrients at a rate equal to that of a 10-
18-1 commercial fertilizer applied at 10
mt/ha. The value of substituting sludge
for commercial fertilizer is clear.
At the 134-mt/ha rate, the EPA and
PDER recommended limits were essentially
met. The trace metal loadings were well
below the limits recommended by EPA,
and except for zinc, they meet all PDER
guidelines.
Surface soil samples were collected
before treatment and analyzed for pH and
buffer pH to determine the liming
requirements. Results indicated that the
average soil pH was 4.3. In September,
13 mt/ha of agricultural lime was
therefore applied to adjust the soil pH to
7.0.
Table 4. Groundwater Analyses for Selected Trace Metals and Nitrate-Nitrogen Following
Maximum Sludge Application* at the Venango County Demonstration Site
Concentration Img/L)
Well No.
Well 1
(control)
•Well 2
(dewatered
sludge.
184 mt/ha)
EPA drinking
water standards
Year]
1977
1978
1979
1980
1981
1977
1978
1979
1980
1981
Cu
0.22
0.23
0.17
0.05
0.06
0.10
0.14
0.18
0.04
0.05
1.00
Zn
4.13
2.02
1.48
0.89
0.83
3.39
3.29
1.83
1.05
0.57
5.00
Cd
0.006
0.002
0.002
0.001
0.003
0.001
0.002
0.001
0.001
0.001
O.010
NO3-N
1.4
<0.5
<0.5
0.6
0.7
1.1
<0.5
<0.5
0.6
0.6
10.0
* 184 mt/ha.
t Values represent the mean of all samples collected from each well for the year.
-------
In September, coal trucks brought the
compost/cake mix from Philadelphia to
the site on a return trip after delivering
coal. The sludge was loaded into manure
spreaders and spread on the site.
Immediately afterward, the area was
chisel-plowed to incorporate the sludge
into the surface 10 cm of spoil material.
After the sludge was incorporated, the
area was broadcast-seeded with a
mixture of Kentucky-31 tall fescue (11
kg/ha), birdsfoot trefoil (6 kg/ha), and
winter rye (63 kg/ha). Completion of
seeding by October 1, 1979, allowed
approximately 6 to 8 weeks for vegetation
to grow and become winter hardy. The
following spring, the remaining portion of
the seeding mixture was broadcast. The
spring seeding mixture was orchardgrass
(11 kg/ha) and birdsfoot trefoil (6 kg/ha).
Results
A site inspection on November 29,
1979 (approximately 8 weeks after
sludge application and seeding) indicated
that a protective cover of winter rye had
been established. Vegetation was approx-
imately 5 cm high. No evidence existed
of any erosion on the sludge-treated area,
and sufficient vegetation appeared to be
established to protect the site from
erosion and runoff over the winter
season. This conclusion was confirmed
by a site inspection on March 28, 1980.
The entire sludge-treated area was
covered by vegetation ranging from 5 to
10 cm high. Based on simple visual
estimates, the cover extended over 80 to
90 percent of the area. No surface runoff
or erosion was evident from the sludge-
treated area, but some erosion did occur
from barren areas upslope of the sludge-
treated area. The sediment-laden surface
runoff from these areas was dispersed as
soon as it encountered the sludge-
treated plot, which had been roughened
by contour chisel plowing to incorporate
the sludge.
By June 1980, the winter rye seed
stalks were well over 1.5m tall (Figure 2),
and the entire sludge-treated area had
developed a 100-percent vegetative
cover. The rye was not harvested; rather
the straw was allowed to collapse to
provide an additional protective organic
mulch on the site until the birdsfoot trefoil
was well established. By September
1981 (2 years after sludge application),
the entire site was predominantly occupied
by a cover of birdsfoot trefoil.
Vegetative growth responses were
evaluated each year. Average vegetation
heights were 68 and 64 cm, an average
dry matter production was 11 and 31
Figure 2. General view of the winter rye vegetative cover the spring after a fall application
of sludge on the Westmoreland County demonstration plot.
mt/ha in 1980 and 1981, respectively.
Results of the analyses for soils,
vegetation, soil percolate, andgroundwa-
ter samples were similar to those reported
for the Venango County demonstration
project. The fall sludge application
caused no significant adverse environ-
mental effects and facilitated the establish-
ment of a complete vegetative cover.
Lackawanna County
The Scranton, Pennsylvania, site
consisted of a 24-ha anthracite refuse
bank devoid of vegetation. The site was
severely eroded and a constant eyesore.
In April 1978, a 4-ha area was recontoured
for the demonstration plot.
A chisel plow was used to loosen the
surface refuse material because of the
compaction caused by the leveling
process. Analyses of surface refuse
samples indicated a pH of 3.6. Thus 11
mt/ha of lime was applied to the area.
Dewatered, vacuum-filtered sludge
was obtained from the Scranton waste-
water treatment plant. The sludge was
first applied with manure spreaders at
rates of 80 and 108 mt/ha and then
incorporated. The area was broadcast-
seeded with the same mixture of grasses
and legumes as in the Venango County
demonstration, and a hay and straw
mulch was applied at the rate of 3.4
mt/ha.
The amounts of trace metals applied by
the two sludge application rates are given
in Table 5 along with the EPA and PDER
guidelines. Both rates yielded trace metal
loadings well below all recommendations.
The highest sludge application rate
provided 1,691 kg nitrogen/ha, 456 kg
phosphorus/ha, and 141 kg potassium/
ha.
Tables. Comparison of State and Federal Recommendations with Trace Metal Loadings
(kg/ha) on the Unburned Anthracite Refuse Site in Lackawanna County
Recommended Maximum
Trace Metal Loadings (kg/ha)
at Two Sludge Application Rates
Constituent
Cu
Zn
Cd
Pb
Ni
Cr
Hg
80 mt/ha
67
64
1.2
49
4.4
16
0.1
108 mt/ha
92
86
1.7
67
5.9
21
0.2
Loadings (kg/ ha)
EPA
ICECS-ISr
280
560
11
1.120
280
AWt
/w?t
PDER
112
224
3
112
22
112
0.6
* Average CEC of site ranged from 11.1 to 11.6 meq/100 g.
t No recommendations given by EPA.
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By August 1978 (2 months after the
sludge application), a complete ground
cover was established. No significant
difference existed in vegetation growth
between the two sludge application rates.
At the end of the first growing season
(1978), average vegetation height was 41
cm and average dry matter production
was 3.6 mt/ha. Average height was
almost double the second year, but it
stabilized at 37 cm after 4 years (1981).
Average dry matter production increased
to 18.7 mt/ha during the first 3 years and
then stabilized at 16 mt/ha in the fourth
year (1981). Analyses of foliar and soil
samples yielded similar results to those
reported for the Venango County demon-
stration project. Sludge applications had
no significant effects on the chemical or
bacteriological quality of soil percolate
water or groundwater.
Production and Quality of
Forage Vegetation
The results of this project were
combined with those of several other
projects to evaluate the effects of sludge
applications to mined land on the
production and quality of forage. Sludge
application rates ranged from 11 to 202
mt/ha, and the vegetation was analyzed
over periods of 2 to 5 years. Vegetation
species evaluated were orchardgrass, K-
31 tall fescue, and birdsfoot trefoil.
Dry matter production (expressed as
hay yield in mt/ha) was consistently
higher on the sludge-amended strip mine
sites than on undisturbed farmland in the
same counties, even for as many as 5
years after sludge application. Crude
protein equaled or exceeded the minimum
for dairy rations. Concentrations of K, Ca,
Mg, Fe and Co (essential in animal diets)
were near or above the minimum suggested
for total dairy rations. Phosphorus, Cu,
and Zn were below these minimum levels
but would routinely be subsidized in sup-
plementary feed concentrates. Concen-
trations of trace metals not required in
animal diets (Pb, Ni, Cd, and Al) were
always below suggested food-chain
tolerance levels. Concentrations of the
essential plant nutrients N, P, and K were
always higher in sludge-grown plants
than in control plants that received
conventional lime and fertilizer applications.
Conclusions
These demonstration projects indicate
that single applications of stabilized
municipal sludges applied at the proper
rate can facilitate revegetation of mined
land and maintain it for a minimum of 5
years in an environmentally safe manner
with no adverse effects on vegetation,
soil, or groundwater quality, and with
little risk to animal or human health.
Specific conclusions are as follows:
1. Springtime applications of various
types of sludges (liquid digested,
dewatered, and composted) at rates
ranging from 7 to 184 mt/ha
facilitated the establishment of a
complete vegetative cover of grasses
and legumes within 2 months.
2. Application of a mixture of dewatered
sludge cake and composted sludge
in the fall at 134 mt/ha produced an
adequate vegetative cover to stabilize
the site over winter and facilitated
the development of a complete
vegetative cover the following sum-
mer.
3. Vegetation growth responses (height
increases and dry matter production)
generally increased for several
years after sludge applications and
then stabilized. All vegetative covers
have persisted for periods up to 5
years without any signs of deteriora-
tion in vegetation yield or quality.
4. Trace metal concentrations in foliage
were generally below suggested
food-chain tolerance levels, and no
phytotoxicity or nutrient deficiency
symptoms were observed on any
sludge-amended site.
5. Sludge applications produced slight
increases in trace metal concentra-
tions in the 0- to 15-cm soil depth.
These increases were minimal and
generally within the normal range A
for soils in the United States (soils ^
that have not been amended with
sludge).
6. Sludge applications and liming
generally increased soil pH signifi-
cantly. These increased pH levels
were maintained for as long as 5
years.
7. Sludge applications did not produce
any significant increases in the
concentrations of NO3-N or trace
metals in the groundwater.
8. Sludge applications did not affect
the bacteriological quality of ground-
water. No groundwater sample
collected during the 5-year period
contained fecal coliform colonies
that could be attributed to the sludge
application.
These findings should be useful
throughout the Appalachian coal mining
region. Demonstration projects such as
those described in this report can be used
effectively to educate the public and gain
public acceptance and support for the
concept of using sludge to revegetate
land disturbed by mining activities.
The full report was submitted in fulfill-
ment of Cooperative Agreement No. CR
807408 by the Pennsylvania'State
University for the Pennsylvania Depart- m
ment of Environmental Resources under ^
the sponsorship of the U.S. Environmen-
tal Protection Agency.
William E. Sopper and Eileen M. Seaker are with Pennsylvania State University,
University Park, PA 16802.
G. K. Dotson is the EPA Project Officer (see below).
The complete report, entitled "Strip Mine Reclamation with Municipal Sludge,"
(Order No. PB 84-152 842; Cost: $17.50, subject to change) will be available
on/y from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Municipal Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
6
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
APh ' 8'84
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ft U.S. GOVERNMENT PRINTING OFFICE: 1984-759
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