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| 2007
Archived Events » |
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March 2-5, 2008
Presenter | Read
Presentation Abstract »
GeoAmericas
Cancun, Mexico
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March 30 - April 02, 2008
Presenter | Read
Presentation Abstract »
WEF Biosolids and Residuals Conference
Philadelphia, PA
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April 2-3, 2008
Presenter | Read
Presentation Abstract »
WEDA Annual Midwest Chapter Meeting
Milwaukee, WI
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June 8-11, 2008
Presenter | Read
Presentation Abstract »
WEDA XXVIII / 39th TAMU DREDGING SEMINAR
St. Louis, MO
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Presentation Title:
Use of Geotube® Dewatering Containers in Environmental
Dredging
by Brian J. Mastin, PhD and Gregg E. Lebster
of WaterSolve, LLC (Grand Rapids, MI) & J.R. Salley
of Kentucky Dredging (Hazard, KY)
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Abstract
Confined Placement Areas (CPAs) are not always a viable
containment and processing option for fine grain residuals
produced during environmental and maintenance dredging.
The objective of this study was to evaluate Geotube containers
as a dewatering option for two environmental dredging projects
including cost effectiveness, ease of operation, solids
and contaminent retention, solids handling time, flow and
volume rates, and seasonality. Geotube containers, with
the aid of dewatering polymers, were recommended to and
implemented by several project engineers into which materials
were dredged and pumped directly from storage lagoons, retention
basins, and waterways. Overall, this dewatering methodology
greatly reduced the volume and mass of residual solids and
costs associated with hauling and disposal while allowing
continual operation of facility lagoons and waterways. If
time and space are available for Geotube operations, Geotube
applications are 80 to 90% less capital intensive compared
to these alternative onsite dewatering techniques.
Keywords
Geotube®, environmental dredging, dewatering, containment,
contaminent retention, solids handling. storage lagoons,
retention basins, waterways, fine grain residuals, dewatering
polymers, dewatering methodology, dewatering techniques.
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Presentation Title:
Is Geotube® Technology a Good Fit for
Residuals Management at your Facility?
by Brian J. Mastin, PhD and Gregg E. Lebster of
WaterSolve, LLC (Grand Rapids, MI); Glenn M. Lundin and
Vicki S. Ginter of TenCate Geotube
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| The Problem
Municipalities across the Midwest typically operate at
greater than 80% capacity and run out of biosolids and back-filter
(lime and alum) residual storage capacity when land application
contractors (if applicable), drying beds, and storage lagoons
are unable to keep up with volume demands. Land application
may not be economically or operationally available, an operations
timeline for solids removal prompts onsite dewatering, and
residuals may be contaminated with metals (e.g., Cu, Fe,
Hg, Mo, Ni, Pb, Zn, etc.), oil and grease (O&G), nutrients,
pathogens, or pesticides. Several mechanical dewatering
options (e.g., belt filter press, centrifuge, etc.) are
available as short-term or long-term remedies for onsite
dewatering but are capital intensive for municipalities
and contractors that already operate on competitive budgets.
The objective of this study was to evaluate Geotube®
containers as a residuals dewatering option for a municipal
wastewater treatment facility (WWTP) and a water filtration
plant (WTP) including cost effectiveness, ease of operation,
solids retention, handling time, flow and volume rates,
and seasonality.
Geotube® Container Sizing
The WWTP produces approximately 500,000 gallons (2,475
yd3) of biosolids contaminated with molybdenum per year
at 5-6 percent dry weight solids. It was calculated that
130 linear feet (lf) of 60’ circumference Geotube®
container would be needed to dewater and contain this annual
volume to 20 percent solids, sufficiently dry to pass a
paint filter test and haul off site to an appropriate landfill.
The resulting volume and mass of residuals at 20 percent
solids would be 562 yd3 and 472 tons, respectively.
The WTP produces approximately 1.19 million gallons (5,874
yd3) of back-filter residual per year at 1.0 percent dry
weight solids. It was calculated that 96 lf of 45’
circumference Geotube® container would be needed to
dewater and contain this annual volume to 20 percent solids,
sufficiently dry to pass a paint filter test and haul off
site to an appropriate landfill. The resulting volume and
mass of residuals at 20 percent solids would be 345 yd3
and 248 tons, respectively.
Chemical Conditioning
WaterSolve performed bench-top dewatering trials for biosolids
and back-filter residual samples (two-gallons) collected
from the WWTP’s liquids storage tank and WTP’s
equalization basin, respectively. Dewatering polymers were
evaluated based on water release rate, water clarity, and
flocculent appearance. In addition, dosing rate(s) were
determined during these bench-top dewatering experiments
and recommendations provided to the facilities during this
phase of the program. Polymer was added to a sludge sample
(150 mL) with a 10-mL plastic syringe and moderately tumbled
five to ten times. We recommended using Solve 214 D at a
dose rate of 300 ppm (2.4 lb/wet ton) for dewatering the
WWTP’s biosolids and Solve 152 at a dose rate of 100
ppm (0.13 lb/wet ton) for dewatering the WTP’s back-filter
residuals.
Bench-scale Evaluation
Water release rates during pumping to a Geotube® container
were evaluated by adding 150-mL flocculated residual samples
to a filter apparatus with a GT500 Geotube® filter.
Water release rate and volume were measured with a 500-mL
graduated cylinder over 12 hours. Remaining solids were
collected and measured for percent dry solids by U.S. EPA
Method 160.3.
The Solution
Geotube® containers, with the aid of dewatering polymers,
were recommended to and implemented by a water filtration
plant and a wastewater treatment facility into which solids
were pumped directly from an equalization basin and above
ground storage tank, respectively. After inline flocculation,
the permeable textile that forms the Geotube® container
allows efficient dewatering while containing the fine grain
solids and the filtrate water returns to the head-works
of the facility. Overall, this dewatering methodology greatly
reduced the volume and mass of residual solids and costs
associated with hauling and disposal while allowing continual
operation of the facilities. For containment and dewatering
of biosolids and back-filter residual, Geotube® dewatering
(including polymer and feed equipment) cost less than $0.03/gallon,
required minimal technical assistance to install and operate,
retained greater than 95 percent solids, solids dried sufficiently
for hauling and disposal (18 to 40 percent cake solids),
and did not interfere with plant operations. Compared to
the previous management techniques (i.e., belt filter press
or hauling to a landfill), these Geotube® projects saved
both facilities nearly $25,000 after the first year of operations. |
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Presentation Title:
Dewatering of Contaminated Dredge Residuals
by B.J. Mastin, PhD, Gregg E. Lebster,
and Mike Broering
WaterSolve, LLC of Grand Rapids, Michigan
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Abstract
Technological advances in the use and application of polymers
and other chemical conditioning agents for the expedient
separation of contaminated solids from water have facilitated
the use of geotextile tubes for containment, dewatering,
and consolidation of hydraulically excavated materials.
This new and innovative technology has been successfully
used to dewater fine-grained, contaminated material that
contained dioxins, polychlorinated biphenyls (PCBs), polyaromatic
hydrocarbons (PAHs), pesticides, metals (with a lithic biogeochemical
cycle), and other hydrophobic materials. The objective of
these dewatering performance trials was to develop a site-specific
chemical conditioning program for each potential Geotube
dewatering application. Polymers were evaluated based on
water release rate, water clarity, flocculent appearance,
and water volume after passing through a Geotube geotextile
filter. In addition, dosing rate(s) were determined during
these bench-top dewatering experiments and recommendations
were provided as a part of these trials. Geotube hanging
bag performance evaluations were also performed with the
recommended chemical conditioning program to evaluate filtrate
quality and time to attain desired cake solids within the
Geotube container. Once a recommended chemical conditioning
program was identified, other chemical application variables
were evaluated for potential full-scale operations including:
1) Use of more than one chemistry as sediment character
changes with depth, debris, organic matter, and density;
2) Simultaneous or sequential application of more than one
chemistry; 3) Application of an inorganic chemistry in combination
with an organic chemistry; 4) Effects of mixing energy and
shear energy during introduction of flocculating chemistry
inline; and 5) Use of pre- and post-dilution. Overall, containment
and dewatering of solids with Geotube containers (including
dewatering polymer and feed equipment) costs less than $0.02
per gal (greater than 1,250 cubic yards in situ), requires
minimal technical assistance to install and operate, retained
greater than 95-percent solids, solids were only handled
once they were dried sufficiently for hauling and disposal
(18 to 80-percent cake solids), did not interfere with site
and facility operations, and the lay-down area for containment
of 1,000 cubic yards of solids production was 672 square
yards (6,050 square ft).
Keywords
Dewatering, Geotube® container, contaminated dredge
residuals, polymers, environmental dredging. |
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Presentation Title:
Dewatering of Oil-Contaminated Dredge Residuals
by B.J. Mastin, PhD and Gregg E. Lebster
WaterSolve, LLC of Grand Rapids, Michigan
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Abstract
Confined Disposal Facilities (CDFs) and in situ technologies
(e.g., capping) are typically not viable risk mitigating
options for oil-contaminated residuals generated during
environmental dredging due to potentially toxic constituents.
Under normal CDF operations, water is discharged over a
weir structure or allowed to migrate through the dike walls
while contaminated solids are retained within the CDF. However,
oil constituents (e.g., PAHs and metals) may be lost via
effluent during filling operations, surface runoff, seepage
through the bottom and dike walls, volatilization, and uptake
by plants and animals. Containment and dewatering technology
is typically used to condition contaminated sediments such
that they meet the requirements of subsequent treatment
and/or disposal components of the remedial alternative as
well as decrease the volume and mass of sediments that require
transport, treatment, or restricted disposal. Several mechanical
dewatering options (e.g., belt filter press, centrifuge,
etc.) are available as short-term or long-term remedies
for onsite dewatering but are capital and resource intensive
for facilities and contractors that operate on competitive
budgets. The objective of this study was to evaluate Geotube®
containers as a dewatering option for oil-contaminated residuals
generated during hydraulic dredging of a historic shipping
channel and storage lagoon of a former and active petroleum
refinery, respectively. Potential dewatering alternatives
were evaluated by cost effectiveness, ease of operation,
solids and contaminant retention, solids handling time,
residual flow rates, footprint requirements, and seasonality.
After inline flocculation with dewatering polymers, the
permeable geotextile that forms the Geotube® container
allows efficient dewatering while containing the fine grain
solids. For containment and dewatering of oil-contaminated
dredging residuals, use of Geotubes® (including dewatering
polymer and feed equipment) cost less than $4.85/cy, required
minimal technical assistance to install and operate, retained
>99% solids (including contaminants), solids were only
handled once they were dried sufficiently for hauling and
disposal (20 to 60% cake solids), and did not interfere
with facility operations. Overall, this dewatering methodology
greatly reduced the volume and mass of residual solids and
costs associated with hauling and disposal while allowing
continual operation of facility lagoons and waterways. If
time and space are available for Geotube® operations,
Geotube® applications are 80 to 90% less capital intensive
compared to alternative mechanical dewatering techniques.
Keywords
Dewatering, Geotube® container, oil-contaminated residuals,
polymers, environmental dredging. |
2007
Archived Events » |
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