Abstract is currently not available.
A main problem related to coal ash disposal is the heavy metal content of the residue. In this regard,
experimental results of numerous studies have indicated that toxic trace metals may leach when fly ash
and bottom ash contacts with water.
In this study, fly ash and bottom ash samples obtained from Kemerköy thermal power plant, located on
the south-western coast of Turkey, were subjected to toxicity tests such as the extraction procedures
(EP) and toxicity characteristic leaching procedures (TCLP) of the U.S. Environmental Protection
Agency (U.S. EPA), the so-called Method A extraction procedure of the American Society of Testing
and Material (ASTM). When Pb and Cd concentrations, analysed according to EP and TCLP, were
considered, Kemerköy fly and bottom ash can be classified as a hazardous waste under the principles
of the Federal Resource Conservation and Recovery Act (RCRA).
Based on the geochemical analyses carried out, it was also determined that several toxic trace elements,
such as Pb, Zn, Cd, Cu and Co were enriched at the fly and bottom ash of Kemerköy thermal power plant.
The vertical migration velocity of radionuclides and the ability of soils components to immobilise them,
as the most important parameters of natural-restoration, was studied. The Dose Equivalent Rate
(DER) reduction of external ã-radiation was studied in order to assess its impact on human health. The
vertical migration velocities of 137Cs and 90Sr in typical soils of contaminated regions in Ukraine
(Chernobyl 30-km zone) and Belarus (Gomel region) have been evaluated annually during the last 8
or 10 years since the accident. In most of these soils the migration rate of 90Sr was found to be higher
than this of 137Cs and ranged from 0.71 to 1.54 cm year-1 and 0 to 1.16 cm year-1 respectively. At present
the main part of radionuclides is located in the upper 10 cm soil layer. The ability of the soil components
to immobilise the radionuclides was also investigated from 1989 to 1994 and was found that
approximately 57% of 137Cs was converted in fixed forms. It is expected that this percentage will
increase to 80% in the next years. Finally, we studied how the DER of ã-radiation, which changes with
the migration of radionuclides in the soil, affects the human health. In comparison with 1986, when
100% of 137Cs was distributed on the soil surface, a significant reduction of DER occurred in the studied
areas and about ten years after the Chernobyl accident, it ranges from 17.5% to 45%, depending
mainly on the level of initial contamination of soils and its migration velocity.
The development of a conceptual site model (CSM) is an invaluable tool used for assessing and planning
remedial actions at a contaminated site. The CSM incorporates site-specific, hydrogeologic and
geochemical information to identify contaminants of concern, sources of pollution, environmental
pathways and retardation mechanisms, and points of exposure. The model is dynamic and continually
revised as new information is obtained during the course of investigation. A ground water contamination
case study is examined to illustrate the development and application of a CSM. The site is a metal
plating facility that has contaminated the ground water with chromium. The CSM was incorporated
into a 3-D fate and transport model. The Heavy Metal model, HM-3D, was used to simulate the fate
and transport of chromium at the site and evaluate pump-and-treat remediation scenarios.
A multi-layered three-dimensional hydrodynamic model has been developed to provide flow fields and
water level changes in Hamilton Harbour. The field data collected in Hamilton Harbour during 1990
& 1991 field seasons was used for model verification. The simulated currents were compared with current
meter data. Results from the trajectory model are in good agreement with the drogue experimental
data. A quantitative criterion to evaluate the trajectory comparison was established with the help of
the trajectory model using the random-walk approach. By using the water level changes in the
Burlington Ship Canal, the model predictions were validated with the measurements at three water
level stations in the Harbour. These comparisons demonstrate that the models can simulate the major
features of the water current and level changes in Hamilton Harbour.
The problem of the passive contaminant spreading in a steady viscous fluid stream is discussed while the
admixture's dissipation and diffusion are taken into account. The channel is assumed to be a horizontal
plane, curvilinear and quite lengthy, so that the ratio of the stream width to its length can be regarded as
a small parameter. A mathematical model of the process derived by the small parameter technique from
the 2D steady Navier-Stokes equations for incompressible viscous fluid and non-steady convection-diffusion
equation of a substance in the moving medium is introduced. A finite element method is applied for
numerical study of the proposed model and results of computer experiments are presented.
The present studies aimed to obtain clean fuel combustion and get detailed information about the
processes that determine the electric field effect on NOx formation in flame channel flows. The experimental
studies demonstrate that the interaction between the radial electric field and the flame initiates
the field-forced drift motion of positive radical ions in a field direction. The energy exchange
between ions and gas particles produces interrelated heat and mass transfer to the negatively biased
channel walls. Hence, by varying the applied voltage, a field-enhanced reducing of a flame temperature
is obtained, thereby lowering thermal NOx formation during the fuel combustion up to 30-80%.
Field experiments have been conducted to investigate flow and dispersion through obstacle arrays.
Model obstacles which represent real structures at a nominal scale between 1/10 and 1/20 were used.
The main purpose of the experiments was to examine flow and dispersion of contaminants in the vicinity
of individual obstacles embedded in an array of cubes. Two array configurations were used, namely
the in-line and staggered array configurations. The field experiments were supported by flow visualisation
trials performed in the wind tunnel. In the light of the results of these wind tunnel trials, the field
experiments were carried out using an array spacing S/H = 1.5 (where S is the space between two consecutive
array elements). Dispersion around an isolated model building has already been investigated
in the field (Mavroidis and Griffiths, 1996). Thus comparison is allowed between dispersion around an
isolated obstacle and around the same obstacle embedded in an array of cubes.
The aim of this paper is to identify the factors that have influenced changes in the amount of carbon
dioxide (CO2) emitted from the Greek manufacturing sector as a whole and from three representative
subsectors. By means of an algebraic decomposition method the changes recorded during the period
1985-95 are analysed into four distinct factors: output level, energy intensity, fuel mix and structural
change. The results show that the observed reduction of industrial CO2 emissions is not only due to the
decrease of industrial energy intensity but also to the recession of the Greek manufacturing sector. The
two other factors, namely sectoral and fuel shifts were driving emissions upward, primarily because of
the increasing share of electricity - intensive sectors and the growing dependence of electricity generation
from lignite. It is concluded that for the reduction of industrial CO2 emissions in the long term,
policy measures should aim at further promoting energy saving technologies and encouraging the use
of natural gas and renewable energies.
Fire agencies worldwide apply millions of gallons of fire suppression chemicals on a broad array of
ecosystems. These chemicals are considered to have minimal effects on the health of people who might
be exposed to them. Only incidents of skin and eye irritation have been reported as a result of prolonged
fire retardant and firefighting foam contact. Fire suppression chemicals have minor toxicological
or ecological effects and, as a result, do not generally harm terrestrial ecosystems. Major impacts,
suppression chemicals have on the environment, may be through the adverse effects on water quality,
and subsequently to aquatic ecosystems. Retardants may encourage eutrophication and, in some cases,
contribute to fish kill when applied on watersheds, or if accidentally applied directly to water bodies.
Foams are generally more toxic than retardants to aquatic biota, but they are applied in much smaller
quantities. Application of retardants increases the total amount of smoke and airborne particulate produced,
but air quality implications are minimal since additional smoke emission by the retardant is
insignificant compared to the major output by the wildfire. Recommendations are offered for mitigation
of potential human health and environmental impacts from the use of fire suppression chemicals,
nevertheless, risks must be assessed on a site-by-site basis.