United States
Environmental Protection
Agency
Municipal Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-81-182 Oct. 1981
Project Summary
Revegetating Strip-Mined
Land with Municipal
Sewage Sludge
William E. Sopper and Sonja N. Kerr
The use of municipal sludge to
revegetate mined land in an environ-
mentally acceptable manner was
demonstrated on several 4-ha plots in
the anthracite and bituminous coal
mining regions of Pennsylvania.
Three sites representative of aban-
doned, barren bituminous and anthra-
cite mines were treated with various
types of municipal sludge at high and
low application rates and broadcast
seeded with a mixture of grasses and
legumes. A monitoring system was
installed at each demonstration site to
determine the effects of the sludge
application on the chemical and
bacteriological quality of groundwater
and soil percolate water, chemical
properties of the soil, and quality and
growth of vegetative cover.
Data collected during the 3-year
period indicate that the sludge appli-
cations ameliorated the harsh site
conditions and resulted in a quick
vegetative cover that completely
stabilized the demonstration site.
Moreover, each site's vegetative
cover has persisted and improved
each year since its establishment. No
deterioration in yield or quality of
vegetation has been observed. Al-
though sludge applications increased
some trace metal concentrations in
the vegetation, all concentrations
were below plant tolerance levels and
no phytotoxicity was observed. Sludge
applications have had no significant
adverse effect on the chemical or
bacteriological quality of soil percolate
or groundwater.
The results from these demonstra-
tion projects indicate that stabilized
municipal sludges, if applied properly.
can be used to revegetate mined lands
in an environmentally safe manner
with no adverse effects on the vege-
tation, soil, or groundwater quality.
This Project Summary was devel-
oped by EPA's Municipal Environ-
mental Research Laboratory, Cincin-
nati, 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 at back).
Introduction
Much of our Nation's need for energy
is currently being supplied and will
probably continue to be supplied from
our coal reserves. With the increasing
price of oil, the demand for coal is
expected to more than double by 1985.
Though the production of anthracite
coal from deep mining has been decreas-
ing, the production of bituminous coal
by strip mining has been steadily
increasing. Estimates show that strip
mining will account for 67 percent of the
anticipated increased production.
The strip-mining industry has already
disturbed approximately 1.6 million ha
of land in the United States, of which,
slightly less than 607,500 ha has been
properly reclaimed. Strip mining of
bituminous coal has affected 31 states.
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The U.S. Geological Survey has esti-
mated that approximately 2,590 km2 of
land is disturbed annually by strip
mining. In Appalachia alone, more than
400,000 ha of land has been disturbed
by strip mining, with more than 25
percent of it in Pennsylvania. Only half
of this land has been adequately
revegetated. In Pennsylvania, strip and
surface mining of coal has adversely
affected an estimated 4,800 km of
streams and 810 ha of impoundments
as a result of erosion and acid mine
drainage. In addition, it has caused the
loss of productive cropland and forest-
land, wildlife habitat, recreational, and
hunting areas. Though current mining
laws require proper back-filling and
restoration of the land, much of the
mining was done before such laws
existed. Many of the old strip mine sites
are a constant source of silt in streams
from soil erosion. The rain that falls on
these sites erodes the mine spoil and
carries it to natural water courses,
where it causes pollution of surface
streams or rapidly percolates through
the porous spoil material and adds to the
acid drainage problems of the mining
areas. The lack of a vegetative cover on
old sites thus contributes to pollution
from both soil erosion and acid drainage.
Strip mine spoils are notoriously
difficult to revegetate. Most provide a
harsh environment for seed germination
and subsequent plant growth. Major
problems are usually a lack of nutrients
and organic matter, low pH, low water-
holding capacity, toxic levels of trace
metals, and poor physical characteristics.
To alleviate these conditions, large
applications of lime and fertilizer are
often required. In some instances,
organic soil amendments and mulches
are necessary to obtain satisfactory
vegetation establishment.
Cities and towns throughout Appa-
lachia have benefited from Federal and
State sewage treatment plant construc-
tion grants. The construction of treat-
ment plants has done much to reduce
health hazards, abate water pollution,
and upgrade water quality. The cost of
operating such plants places a burden
on municipalities, and one of the most
costly items in treatment plant budgets
is sludge disposal. Higher degrees of
sewage treatment result in larger
quantities of sludge that must be
handled in an environmentally satis-
factory manner.
Sewage sludge incinerators were
used to dispose of sludge for many
years. The ash produced was landfilled
and presented no particularly difficult
disposal problems. Incinerators are now
being phased out of service throughout
Pennsylvania as air quality standards
become more restrictive. The high cost
and limited availability of fuel to fire
conventionally designed incinerators
have contributed to the rapid decline in
sludge incineration in Pennsylvania.
This changing situation presents a
problem and an opportunity. More
sludge that could be applied construc-
tively to land renovation will now be
available.
During the past decade, a considerable
amount of research has been conducted
that has shown that stabilized municipal
sludge from secondary wastewater
treatment plants is an excellent soil
amendment and chemical fertilizer
substitute. It is estimated that more
than 4.5 million dry metric tons (mt) of
municipal sludge is currently being
produced annually in the United States.
By the time secondary treatment is
achieved by all wastewater treatment
facilities across the country, this volume
of sludge may reach 8 million dry mt per
year. Current methods for sewage
sludge disposal are land filling (40%),
incineration (25%), ocean dumping
(15%), and land application (20%). Of
these, only land application provides an
opportunity for disposal and beneficial
use at the same time.
Farmers have used animal wastes as
soil conditioners for centuries. Sewage
sludges have been used for this purpose
in many parts of the world. The avail-
ability of inexpensive chemical fertilizers
in the United States probably has
resulted in limited instances of sewage
sludge being used as a soil builder and
conditioner. Recent increases in the
cost of chemical fertilizer should make
the nutrient content of sewage sludge
more attractive to farmers.
Though the benefits of using sewage
sludge seem obvious, there is some
reluctance on the part of farmers and
local government officials to undertake
such projects. It was quite obvious that
we had to bridge the gap between
available technical information and
public understanding. To accomplish
this, a cooperative project was initiated
in 1977 with funding from the U.S.
Environmental Protection Agency (EPA)
to establish 4-ha (10 acre) demonstration
plots in both the anthracite and bitum-
inous coal mining regions of Pennsyl-
vania. Cooperating in this effort were
the Pennsylvania Bureau of Solid Waste
Management, the Pennsylvania office
of the USDA Agricultural Stabilization
and Conservation Service, and the
Appalachian Regional Commission.
This effort was expanded in 1978 in
cooperation with the City of Phila-
delphia Water Department and Modern-
Earthline Companies.
Projects were conducted using several
types of sludges on a variety of site
conditions. Types of sludges used were
(1) liquid digested, (2) dewatered by
centrifuge, vacuum filter, and sand bed
drying, and (3) compost—sludge-cake
mix. Site conditions evaluated were
bituminous strip mine banks and an
anthracite refuse bank that were
recontoured without soil replacement.
Bituminous Strip Mine Banks
This site, located in Venango County,
is representative of bituminous strip
mine banks, that have been backfilled
and recontoured after mining without
soil replacement. Several attempts had
been made to revegetate the area using
lime, commercial fertilizer, and seed but
without success. The surface spoil was
compacted, extremely acid (pH 3.8), and
devoid of vegetation. A 4-ha demonstra-
tion plot was established. The plot was
scarified with a chisel plowto loosen the
surface spoil material and then treated
with agricultural lime (4.5 to 12.3
mt/ha) to raise the spoil pH to 6.5.
Sludge for the project was obtained
from three local waste treatment plants.
Liquid digested sludge, obtained from
the cities of Farrell and Oil City, was
transported to the site in tank trucks.
Dewatered sludge was obtained from
Franklin where the sludge is dewatered
bycentrifuging, 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 (Figure
1). Liquid digested sludge was applied
with a vacuum tank liquid manure
spreader at 103 rnVha (equivalent to 7
mt/ha) and 155 rnVha (equivalent to 11
mt/ha). Dewatered sludge was applied
at 90 and 184 mt/ha.
Immediately after sludge application
and incorporation, the site was broad-
cast seeded with a mixture of two
grasses and two legumes. The seeding^
mixture was Kentucky-31 tall fescue^
(22 kg/ha), Pennlate orchardgrass (22
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Figure 1. Spreading composted sludge on a bituminous strip mine after liming.
nitrogen is released the second year.
Decreasing amounts of organic nitrogen
are subsequently released each year.
After this period, the natural process of
nutrient recycling should be well
established for sustaining the vegeta-
tion.
All sludge treated areas had a
compete vegetative cover established
within several weeks after sludge was
applied (Figure 2). Vegetation growth
and dry matter production were mea-
sured at the end of each growing season
(1977 to 1979) (Table 3). Both vegetation
height growth and dry matter production
increased during the 3-year period.
Samples of the individual grass and
legume species were collected at the
end of each growing season for foliar
analyses. Results for tall fescue and
birdsfoot trefoil for the highest sludge
application rate are given in Table 4.
kg/ha), Penngift 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 amounts of trace metals applied
at the highest liquid and dewatered
sludge application rates are given in
Table 1 along with the EPA and
Pennsylvania Department of Environ-
mental Resources (PDER) interim gui-
deline recommendations. It is quite
obvious that the amounts of trace
metals applied even at the highest
sludge application rate were well below
the recommended lifetime limits except
for copper, which slightly exceeded the
Pennsylvania guidelines.
The amounts of nutrients applied by
each of the sludge application rates are
given in Table 2. Potassium is the only
plant nutrient deficient in all sludge
application rates. The commercial
fertilizer equivalents are also given in
Table 2. The highest sludge application
rate (184 mt/ha) was equivalent to
applying an 11-9-0 commercial chem-
ical 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 approximately 20
^percent of the organic nitrogen is
mineralized in the first year and 5 to 10
percent of the remaining organic
Table 1. Trace Metal Loadings (kg/ha) of the Highest Liquid and Dewatered Sludge
Applications at the Venango County Demonstration Compared with EPA
and PDER Recommendations.
kg/ha Loading at
Sludge Application
Constituent
Cu
Zn
Cd
Pb
Ni
Cr
Hg
Rates
11
21
21
0.1
10
1
16
0.01
(mt/ha)
184
129
147
0.6
55
12
74
0.09
kg/ha Recommendations
EPA" PDER
(CEC 5-15)
280
560
11
1,120
280
A//?2
NRZ
112
224
3
112
22
112
0.6
' Average CEC of site ranged from 11.6-15.2 meq/IOOg.
2/Vo recommendations given by EPA.
Table 2. Commercial Fertilizer Equivalents of the Sludge Application at the
Venango County Demonstration Site.
Sludge Application
Rate, Amount,
mt/ha kg/ha
184'
90
11
7
22,400
1 1,200
2,240
2.240
Fertilizer Equivalent (Fertilizer Formula) 1
N.
kg/ ha (%)
2.388(11)
1,165(10)
284(13)
187( 8)
P205,
kg/ ha (%)
2.103(9)
1.026(9)
143(6)
95(4)
K2O,
kg/ha(%)
21(0)
11(0)
6(0)
2(0)
example, 184 mt sludge/ha is equivalent to 11-9-0 fertilizer at 22,400/ha.
3
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I
Figure 2. Vegetation growth on same area as Figure 1 three months after sludge
application.
Table 3. Vegetation Height Growth (cm) and Dry Matter Production (kg/ha) at the
Venango County Demonstration Site for the Highest Liquid and
Dewatered Sludge Applications.
Sludge
Application, mt/ha
11
184
11
184
1977
32
35
7,731
6.013
1978
Height, cm
30
52
Dry Matter Production, kg/ ha
8.654
9.336
1979
43
44
17,141
1 1.322
Table 4. Average Concentration f/jg/g) of Trace Metals in the Foliar Samples
Collected from the 184 mt/ha plot at the Venango County
Demonstration Site.
Species
Year
Cu
Zn
Cd
Tall Fescue
Birdsfoot Trefoil
1977
1978
1979
1977
1978
1979
9.4
8.6
9.2
13.9
7.7
9.2
44.4
44.4
72.5
95.9
30.4
41.5
0.20
0.41
0.08
0.43
0.07
0.04
Suggested Tolerance
Level
150
300
Foliar trace metal concentrations gen-
erally decreased over the 3-year period.
Overall, the trace metal concentrations
were well below the suggested tolerance
levels and no phytotoxicity symptoms
were observed.
In general, the vegetation cover has
improved over the three growing seasons
following sludge application (Figure 3).
No deterioration in vegetation quality or
yield has been measured or observed. In
comparison, the remainder of the site,
not treated with sludge, remained
barren.
Spoil samples were collected at the
end of each growing season to evaluate
the effect of the lime and sludge
applications on spoil pH. Results indicate
that, for the highest sludge application
(184 mt/ha), after lime and sludge was
applied the spoil pH at the 0- to 15-cm
depth increased from 3.8 to 6.2 at the
end of the first growing season.
Surface spoil pH continually increased
over the 2.5-year period following
sludge application. Results indicate that
the lime and sludge applications did
raise the spoil pH significantly and that
the higher pH was maintained. After the^
3-year period, surface spoil pH was 7.3.^
Spoil samples were also analyzed for
trace metals. A comparison of trace
metal concentrations before and after
sludge was applied indicate that even at
the highest sludge application rate (184
mt/ha) the trace metal concentrations
in the surface spoil (0 to 15 cm) were
only slightly increased. In general, the
trace metal concentrations in the spoil
were all extremely low in comparison
with normal ranges for soils.
Groundwater samples were collected
every two weeks from monitoring wells
to evaluate the effect of the sludge
applications on water quality (Table 5).
Well No. 1 was drilled as a control
outside the area of influence of the
sludge applications. Groundwater flow
under the dewatered sludge-treated
area is toward Well No. 2 located
approximately 11 mdownslope from the
plot. Results indicate that the high
application of dewatered sludge did not
significantly increase the concentration
of NOs-N in groundwater. Concentra-
tions of NOa-N were below theEPAIimit
for potable water (10 mg/l) for all
months sampled. It also should be noted
that the average depth to groundwater
in Well No. 2 was only 3 m. There
appears to be no significant increase i
any of the trace metal concentrations i
Well No. 2, which was influenced by the
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Figure 3.
Table 5.
Well No.
During the second year following sludge application the grass species
are slowly replaced by legume species fbirdsfoot trefoil in photo).
Groundwater Analyses for Trace Metals and Nitrate-Nitrogen (mg/l)
Following Sludge Application (184 mt/ha) at the Venango County
Demonstration Site.
Year'
Cu
Zn
Cd
N03-N
We// 7
(Control)
Well 2
(Dewatered
Sludge,
184 mt/ha)
EPA Drinking
Water Standard
1977
1978
1979
1977
1978
1979
0.22
0.23
0.17
0.10
0.14
0.18
1.00
4.13
2.02
1.48
3.39
3.29
1.83
5.00
0.006
0.002
0.002
0.001
0.002
0.001
0.010
1.4
<0.5
<0.5
1.1
<0.5
<0.5
10.0
1 Values represent the mean of all samples collected from each well for the year.
sludge applications. Average annual
concentrations were below the EPA
drinking water standards.
All groundwater samples collected
during the period July 1977 to Septem-
ber 1980 were also analyzed for
coliforms. No fecal coliform colonies
were observed for any sample.
To maximize the value of the demon-
stration project, a second site was
chosen on abandoned bituminous spoil
I for a fall sludge application. This would
allow the evaluation of a fall seeding to
establish a vegetative cover and the
efficacy of that cover to control the
environmental effects of the sludge
application. During the spring of 1979, a
site was located in the bituminous coal
region of Southwestern Pennsylvania in
Derry Township, Westmoreland County.
The area had been mined approximately
10 years ago and is typical of bituminous
spoil banks that had been recontoured
without topsoil replacement. Four
hectares of the approximate six hectare
area was selected for sludge application.
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 of the composted
sludge is approximately 0.6 percent;
whereas, the centrifuged sludge cake
total nitrogen content is approximately
2.0 percent.
Results of the analyses of the compost-
cake mix were used to calculate the
amounts of selected nutrients and trace
metals applied. The 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 to
the area. This would be equivalent to
applying a 10-18-1 commercial fertilizer
at 10 mt/ha. The value of sludge as a
substitute for commercial fertilizer is
obvious.
A comparison of the application rate
with the EPA and PDER recommen-
dations for maximum trace metal
loadings on the land indicates that the
recommended limits were essentially
met with the slude application rate of
134 mt/ha (Table 6). At an application
rate of 134 mt/ha, the trace metal
content of the sludge is well below the
limits recommended by the EPA and,
with the exception of zinc, meets all
PDER guidelines.
Pretreatment surface soil samples
were collected 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 agricultural lime/ha were applied
to adjust the soil pH to 6.0. Monitoring
instruments were installed, including
suction lysimeters at the 90-cm depth
and groundwater wells.
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 after the spreading,
the area was chisel plowed to incorporate
the sludge into the surface 10 cm of
spoil material.
After incorporating the sludge, 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
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Table 6. Trace Metal Loadings (kg/ha) at the Westmoreland County Demonstration
Project Compared with EPA and PDER Recommendations.
Constituent
Cd
Cu
Cr
Pb
Hg
Ni
Zn
kg/ha Loading at
Sludge Application
of 134 mt/ha
0.2
76
42
59
0.06
13
245
kd/ha Recommendations
EPA PDER
f CEC 5-1 5)'
22 3
560 1 12
NR2 1 12
2.240 112
NR2 0.6
560 22
1.120 224
1Average CEC of site ranged from 16.7 to 19.0 meg/IOOg.
2No recommendation given by EPA.
approximately 6 to 8 weeks for vegeta-
tion growth to become winter hardy.
A site inspection in November,
approximately 8 weeks after seeding,
indicated that a protective cover of
winter rye had been established.
Vegetation was approximately 5 cm in
height. There was no evidence of any
erosion on the sludge treatment area. It
appeared that sufficient vegetation was
established to protect the site from
erosion and runoff over the winter
season. This was confirmed by a site
inspection in March 1980. The entire
sludge-treated area developed a vege-
tative cover ranging from 5 to 10 cm in
height. From 80 to 90 percent of the
area appeared to be covered and there
was no evidence of surface runoff or
erosion from the sludge-treated area.
As soon as the site was dry enough, the
remaining portion of the seeding
mixture was broadcast. The spring
seeding mixture was Orchardgrass (11
kg/ha) and Birdsfoot trefoil (6 kg/ha).
By early summer, there was a complete
lush vegetative cover on the entire site.
At the end of the first growing season
(1980), average vegetation height was
68 cm and average dry matter product
was 11,036 kg/ha. This would indicate
that sludge can successfully be applied
in the fall as well as the spring.
Results of the analyses of ground-
water well samples indicated that
sludge application did not have any
apparent effect on the concentration of
any constituents. The concentration of
NOa-N in the groundwaterwas7.1 mg/l
during the first month following sludge
application and remained at a low level
during the period of sampling. Concen-
trations of all trace metals except lead
were below the maximum allowable
limits for potable water. Lead concen-
trations exceeded the EPA standards on
both the control and sludge-treated
area.
Anthracite Refuse Bank
A 24-ha anthracite refuse bank,
devoid of vegetation, in Scranton,
Pennsylvania, was subject to severe
erosion and was a constant eyesore. To
demonstrate that the sludge can be
used in an environmentally acceptable
manner in the cities as well as in the
rural areas, 4-ha of this area was
selected for reclamation with sludge.
In April 1978, the 4-ha area was
recontoured. A cfcisel 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; therefore 11 mt lime/ha was
applied to the area. Monitoring instru-
mentation was installed to collect soil
percolate water at the 90-cm depth;
groundwater wells were drilled to
monitor the effect of the sludge on the
groundwater leaving the site. Dewatered,
vacuum-filtered, sludge was obtained
from the Scranton waste water treat-
ment plant. The sludge was applied at
80 and 108 mt/ha rates with manure
spreaders and incorporated. The area
was broadcast seeded with the same
mixture of grasses and legumes as in
the Venango County demonstration.
The area was then mulched with hay
and straw at the rate of 3.4 mt/ha.
The amounts of trace metals applied
by the two sludge application rates are
given in Table 7 along with the EPA and
PDER guideline recommendations.
Both sludge application rates were well
below all recommendations for maxi-
mum trace metal loadings. The highest
sludge application rate applied 1,691 kg
nitrogen, 456 kg phosphorus, and 141
kg potassium/ha.
By August 1978, 2 months after the
sludge application, a complete vegetative
cover was established. There was no
significant difference in vegetation
growth between the two sludge appli-
cation rates. At the end of the first
growing season (1978), average vege-«
tation height was 41 cm and average dry^
matter production was 3,655 kg/ha
(Figure 4). By the end of the second
growing season (1979), these values
more than doubled.
After sludge was applied, samples
from the groundwater monitoring wells
were collected every 2 weeks. Results
indicate that the sludge applications
had little effect on the groundwater
quality, with all sample concentrations
of nitrate-nitrogen remaining well
below EPA limits for potable water. Zinc
was the only trace metal that increased
Table 7. Trace Metal Loadings (kg/ha) on the Unburned Anthracite Refuse
Site in Lackawanna County Compared with EPA and PDER
Recommendations.
Constituent
kg/ha Loading at
Sludge Application
Rate (mt/ha)
80 108
kg/ha Recommendations
EPA PDER
(CEC 5-15?
Cu
Zn
Cd
Pb
Ni
Cr
Hg
67
64
1.2
49
4.4
16
0.1
92
86
' 1.7
67
5.9
21
0.2
280
560
11
1,120
280
NR2
NR2
112
224
3
112
22
112
0.6
1'Average CEC of site ranged from 11.1 to 11.6 meq/100g.
2No recommendations given by EPA.
6
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Figure 4. Dense vegetative cover established on an anthracite refuse bank fol-
lowing an application of dewateredsludge at 108 mt/ha in Scranton, PA.
in concentration in the groundwater;
however, the highest Zn concentration
recorded (1.35 mg/l) was still well
below the 5 mg/l drinking water
standard for Zn. Separate samples were
collected for bacterial analyses. No fecal
coliforms were found in any sample to
date.
4. All foliar trace metal concentrations
were below plant tolerance levels,
and no phytotoxicity symptoms were
observed.
5. Trace metal concentrations in the
soil increased slightly because of the
sludge application. These concen-
trations, however, were extremely
low and were below the normal
range for untreated soils.
6. Sludge application and liming sig-
nificantly increased soil pH, and
these increased pH levels were
maintained throughout the study
period.
7. No significant increases in concen-
trations of nitrate-nitrogen or trace
metals occurred in the groundwater
due to the sludge applications.
8. No fecal coliform colonies were
observed in any groundwater samples
collected during the study period.
All projects were highly successful.
Project results should be useful through-
out the Appalachian coal mining region.
Both sludge production and strip mining
of coal are increasing, and there is an
urgent need to solve the environmental
problems associated with both activities.
Results indicate that the use of these
small local demonstration projects is
one of the best methods of obtaining
public acceptance and support for the
revegetation of strip-mined land using
municipal sewage sludge.
The full report was submitted in
fulfillment of Grant No. S-804511 by
Pennsylvania State University, Univer-
sity Park, Pennsylvania 16802 under
the sponsorship of the U.S. Environ-
mental Protection Agency.
Conclusions
The results from these demonstration
projects indicate that stabilized munici-
pal sludges can be used to revegetate
bituminous strip-mined land and an-
thracite refuse banks in an environ-
mentally safe manner with no adverse
effects on vegetation, soil, or ground-
water quality and with little risk to
animal or human health. Specific
conclusions are as follows:
1. Application of sludge in the spring
produced a complete vegetative
cover of grasses and legumes within
2 months.
2. Application of sludge in the fall
produced a complete vegetative
cover by the following summer.
k3. Vegetation height and dry matter
production increased each year
following sludge application with no
deterioration of productivity observed.
W. E. Sopper and S. N. Kerr are with the Department of Environmental
Resources, Pennsylvania State University, Harrisburg, PA 17120.
G. K. Dotson is the EPA Project Officer (see below).
The complete report, entitled "Revegetating Strip-Mined Land with Municipal
Sewage Sludge." (Order No. PB 82-102 484; Cost: $14.00, subject to change)
will be available only 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
U.S. GOVERNMENT PRINTING OFFICE : 1981 --559-092/331 5
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EPA 335
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Penalty for Private Use $300
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