Get documents about "Characteristics of Composts Moisture Holding and Water Quality
Description
Characteristics of Composts Moisture Holding and Water Quality
Shared by: benbenzhou
-
Stats
- views:
- 5
- posted:
- 6/25/2010
- language:
- English
- pages:
- 4
Document Sample
CENTER FOR TRANSPORTATION RESEARCH
THE UNIVERSITY OF TEXAS AT AUSTIN
Project Summary Report 0-4403-S
Center for
Project 0-4403: Characteristics of Compost Enhanced Topsoils: Moisture
Transportation Research
The University of Texas at Austin Holding and Water Quality Improvement
Authors: Christine J. Kirchhoff, Joseph Malina, Jr., and Michael Barrett
August 2003
Characteristics of Composts: Moisture Holding
and Water Quality Improvement
Introduction rights-of-way, the effectiveness composted materials;
of various classifications of • Application rates of compost
Composted manures, com-
REPORT
compost in retaining moisture, alone as well as compost
post-amended soils, and erosion in removing constituents of manufactured topsoil (CMT)
control compost (CMT and highway runoff, and in overall to slopes, medians, and
ECC) were applied to highway improvement of water quality other green areas in highway
rights-of-way as a means to in receiving waters has not been rights-of-way;
beneficially dispose of excess defined in detail. The objectives • Water-holding capacity and
manure produced in parts of of this research project are to pollutant attenuation charac-
Texas. These efforts demon- establish the moisture holding teristics of CMT
strated that the application of capacity of different classes of The moisture-holding capac-
composted manures was suc- compost-amended soils and the ity and the physical, chemical
cessful in establishing vegeta- ability of the compost mixtures and microbiological character-
tion and controlling erosion on to retain pollutants commonly istics of composted manures
SUMMARY
highway embankments. TxDOT found in highway stormwater (dairy cattle, poultry litter, and
reports that composted manures runoff. feedlot) and composted biosol-
have been used beneficially, ids were determined. Compost
usually with excellent results What We Did… manufactured topsoil (CMT)
in all fourteen TxDOT districts that contained 75% composted
A comprehensive literature
in which compost was applied. manures or composted biosolids
review was conducted to iden-
However, in spite of the ap- mixed with 25% either sandy
tify:
parent successful application soil or clay soil, and erosion
• Constituents and composi-
of compost to slopes and other control compost (ECC) that con-
tion of various types of
vegetated areas of highway tained 50% composted manure
or composted biosolids and 50%
wood chips were evaluated.
The characteristics of the
PROJECT
leachate produced during “first-
flush” and “extended” column
studies were analyzed to assess
the degree to which stormwater
runoff would leach nutrients,
metals and other constituents
from the CMT and ECC. The
capacity of the CMT and ECC
to retain pollutants in highway
stormwater runoff also was de-
Figure 1: Overall experimental setup termined. The onset of runoff
Project Summary Report 0-4403-S –1–
gravel (0.125 to 0.5 in. diameter). A and to provide drainage of the leachate.
50 mil filter fabric separated the 3 in. A channel that was 3 ft wide and 1 ft
layer of soil, CMT, or ECC, from the long allowed for collection of surface
pea gravel (Figure 2). A spray nozzle runoff and leachate. The slope of the
was positioned above each column. channel could be varied from 2:1 to 8:1
The types of CMT, ECC and soils (horizontal to vertical).
used in the column studies are pre- Tap water was applied to the channel
sented in Table 1, which also illustrates that was positioned at the desired slope
the experimental matrix. Duplicate until the test sample was saturated with
columns were operated for each of the water. Leachate was allowed to drain
CMT and ECC. Two columns, one freely from the soil, CMT, or ECC for
each for the sandy soil and the clay 24 hours. The erosion control test was
soil, were used as controls. begun after waiting 24 hours by apply-
The application rate was approxi- ing a volume of water to the sample in
mately 3.45 in. of simulated rainfall. the erosion control channel to simulate
The “extended” column studies con- the 2 year, 3 hour design storm (ap-
Figure 2: Details of columns with sisted of applying a volume of deion- proximately 2.64 in.)
gravel layers and spray nozzles ized water to each column to simulate
one year of rainfall in Austin, TX. The What We Found…
and peak rate of runoff from CMT and collected leachate was analyzed for The proposed requirements of
ECC were monitored in channel stud- total suspended solids, total dissolved TxDOT Specification Item 161 are
ies at slopes of 2:1, 3:1, 5:1, and 8:1 solids, copper, zinc, total nitrogen, consistent with compost specifications
(horizontal:vertical). ammonia nitrogen, nitrites, nitrates, applied in some 50 states. Composted
total and dissolved phosphorus, fecal biosolids met all the limits specified
Leachate Studies coliform, and fecal enterococci. in the TxDOT Specification Item 161.
Sixteen columns were fabricated However, the composted dairy cattle
for use in the “first flush” and “ex- Channel Studies
The channels were constructed of manure, composted poultry litter, and
tended” leachate studies (Figure 1). the composted feedlot manure failed
The columns consist of 12 in. long, galvanized sheet metal and are 3 ft
wide by 9 ft long and 0.5 ft deep (Fig- to meet the specifications in at least
8 in. diameter acrylic cylinders. Each one category.
column contained a 3 in. base layer of ure 3). The soil bed was 3 ft wide by 8
ft long. A layer of gravel was placed Addition of compost to sandy soil
washed gravel (0.5 to 1.5 in. diameter) and to sandy clay loam increased the
overlaid by a 3 in. layer of washed pea to support the CMT or ECC or the soil
pore size, the range of pore sizes, and
Table 1: Matrix for Evaluating Characteristics of Leachate from Compost-
Manufactured Topsoil Using De-Ionized Water and Actual Highway Runoff
Compost-Manufactured Erosion Control Controls
Topsoil (CMT)
Type of 25% compost 25% compost 50% compost 100% 100%
+ + + sandy clay
Compost 75% sandy soil 75% clay soil 50% wood chips soil soil
X X
Dairy X X X
Manure
Poultry X X X
Litter
Feedlot X X X
Manure
Biosolids X X X
Project Summary Report 0-4403-S –2–
(a) (b)
Figure 3: (a) Channel illustrating effluent launder, and (b) Channel in wooden support
and frame to adjust slope. Effluent flow measurement device is located in the white box.
the porosity of the CMT. The bulk from application of the same compost the TxDOT Specification 161 organic
density of the CMT and ECC decreased or CMT or ECC under field conditions content of 25% to 65%. The organic
compared with the soil controls. The where water passing through the com- bulking material also would provide a
water-holding capacity of the sandy post-amended soils would infiltrate source of carbon which upon aerobic
CMT increased but the water-holding into the underlying soil and be taken decomposition will be converted to
capacity of the clay CMT decreased up by plants and/or undergo chemical carbon dioxide and tend to reduce the
compared to the soil controls. and biological transformations in the pH to less than 8.5.
The water-holding capacity of the soil, resulting in lower concentrations Increasing the amount of organic
compost-amended soils increased com- that would reach surface and ground bulking material in composting poultry
pared to the soil controls. The gains in water sources. litter would have a similar effect on the
water-holding capacity occurred only The highest peak runoff occurred pH of the final product.
with compost amendment of sandy in the erosion control studies at the Composted feedlot manure is not
soils. The available water capacity steepest slope (2:1) for the clay control suitable for use in CMT or in ECC
appeared to increase with compost and the dairy clay CMT blend. The because the composted feedlot manure
amendment of sandy soils but appeared peak runoff rate generally decreased exceeded the specified maximum pH
to decrease with compost amendment with decreasing slope for the control, and salt limit, had a low maturity, and
of clay soils. CMT, and ECC. The onset of runoff exhibited phytotoxicity that would in-
The leachate collected in the “ex- for CMT and ECC at all slopes was hibit the establishment of vegetation on
tended” column studies approximate delayed. ECC blends appeared to delay rights-of-way of new highways.
concentrations of constituents in the runoff more than CMT blends. The Clay or sandy clay are the soils of
leachate over time after numerous clay CMT blends delayed the onset of choice to be blended with composted
applications of water. Total nitrogen runoff compared to clay soil alone at manures and biosolids in Compost
concentrations decrease in total nitro- a 3:1 slope. The onset of runoff was Manufactured Topsoils. The clay
gen in the leachate over time for all delayed 8 to 15 minutes, and the peak CMTs are more efficient in the removal
CMT and ECC blends. Phosphorus runoff flow rate was reduced from 0.5 of total nitrogen, phosphorus, total sus-
concentrations decreased over time for to 0.4 gpm or less. ECC blends delayed pended solids, and heavy metals than
all CMT and ECC mixtures. The total the onset of runoff at a 3:1 slope by 15 sand CMTs.
phosphorous concentration after 12 minutes or more. The maximum slope for the ap-
months of equivalent rainfall was less plication of Compost Manufactured
than 2 mg/L for clay CMT blends and The Researchers Topsoil or Erosion Control Compost is
<10 mg/L for sand CMT blends and Recommend... 3:1 (horizontal:vertical). Runoff delay
ECC blends. Concentrations of copper and reduction in the peak flow rate are
and zinc also decreased over time. Clay Wood chips, yard trimmings, or enhanced at slopes below 3:1.
CMT retained more copper than sand similar materials should be incorpo-
CMT, but the reverse was true for zinc. rated as organic bulking agents when
The concentrations of constituents in composting dairy cattle manure in
the leachate observed in the laboratory order to increase the organic matter
are more concentrated than the leachate content of the finished compost to meet
Project Summary Report 0-4403-S –3–
For More Details...
Research Supervisor: Joseph Malina, Ph.D., P.E., (512) 471-4614
email: jmalina@mail.utexas.edu
TxDOT Project Director: Barrie Cogburn, P.E., (512) 416-3086
email: bcogburn@dot.state.tx.us
The research is documented in the following reports:
0-4403-1 A Review and Evaluation of Literature Pertaining to Compost Characteristics and to the
Application of Compost Alone and Mixed with Different Soils July 2002
0-4403-2 Characteristics of Composts: Moisture Holding and Water Quality Improvement August 2003
To obtain copies of a report: CTR Library, Center for Transportation Research,
(512) 232-3138, email: ctrlib@uts.cc.utexas.edu
TxDOT Implementation Status
February 2004
The research investigated the moisture holding and water quality characteristics of compost. The research
revealed that the application of compost manufactured topsoil and erosion control compost to TxDOT ROW
is effective in enhancing the growth of vegetation, controlling erosion, and attenuating the transport of
constituents of runoff. The research results will be used to promote, demonstrate, and implement the use of
compost in highway projects.
For more information, contact: Sharon Barta, P.E., RTI Research Engineer, at (512) 465-7403 or email:
sbarta@dot.state.tx.us.
Your Involvement Is Welcome!
Disclaimer
This research was performed in cooperation with the Texas Department of Transportation and the U. S.
Department of Transportation, Federal Highway Administration. The contents of this report reflect the views of the
authors, who are responsible for the facts and accuracy of the data presented herein. The contents do not necessarily
reflect the official view or policies of the FHWA or TxDOT. This report does not constitute a standard, specification,
or regulation, nor is it intended for construction, bidding, or permit purposes. Trade names were used solely for
information and not for product endorsement. The engineer in charge was Dr. Joseph Malina, P.E. (Texas No. 30998).
The University of Texas at Austin
Center for Transportation Research Library
Center for 3208 Red River #115
Transportation Research
The University of Texas at Austin
Austin, TX 78705-2650
