Abstract: Anaerobic digestion is a well-known technique for
sustainable energy recovery from sewage sludge. However, sewage
sludge digestion is restricted due to certain factors. Pre-treatment
methods have been established in various publications as a promising
technique to improve the digestibility of the sewage sludge and to
enhance the biogas generated which can be used for energy recovery.
In this study, continuous flow microwave (MW) pre-treatment with
different intensities were compared by using 5 L semi-continuous
digesters at a hydraulic retention time of 27 days. We focused on the
effects of MW at different intensities on the sludge solubilization,
sludge digestibility, and biogas production of the untreated and MW
pre-treated sludge. The MW pre-treatment demonstrated an increase
in the ratio of soluble chemical oxygen demand to total chemical
oxygen demand (sCOD/tCOD) and volatile fatty acid (VFA)
concentration. Besides that, the total volatile solid (TVS) removal
efficiency and tCOD removal efficiency also increased during the
digestion of the MW pre-treated sewage sludge compared to the
untreated sewage sludge. Furthermore, the biogas yield also
subsequently increases due to the pre-treatment effect. A higher MW
power level and irradiation time generally enhanced the biogas
generation which has potential for sustainable energy recovery from
sewage treatment plant. However, the net energy balance tabulation
shows that the MW pre-treatment leads to negative net energy production.
Abstract: Polycyclic Aromatic Hydrocarbons (PAHs) are
formed mainly because of incomplete combustion of organic
materials during industrial, domestic activities or natural occurrence.
Their toxicity and contamination of terrestrial and aquatic ecosystem
have been established. However, with limited validity index, previous
research has focused on PAHs isomer pair ratios of variable
physicochemical properties in source identification. The objective of
this investigation was to determine the empirical validity of Pearson
Correlation Coefficient (PCC) and Cluster Analysis (CA) in PAHs
source identification along soil samples of different land uses.
Therefore, 16 PAHs grouped, as Endocrine Disruption Substances
(EDSs) were determined in 10 sample stations in top and sub soils
seasonally. PAHs was determined the use of Varian 300 gas
chromatograph interfaced with flame ionization detector. Instruments
and reagents used are of standard and chromatographic grades
respectively. PCC and CA results showed that the classification of
PAHs along pyrolitic and petrogenic organics used in source
signature is about the predominance PAHs in environmental matrix.
Therefore, the distribution of PAHs in the studied stations revealed
the presence of trace quantities of the vast majority of the sixteen
PAHs, which may ultimately inhabit the actual source signature
authentication. Therefore, factors to be considered when evaluating
possible sources of PAHs could be; type and extent of bacterial
metabolism, transformation products/substrates, and environmental
factors such as salinity, pH, oxygen concentration, nutrients, light
intensity, temperature, co-substrates, and environmental medium are
hereby recommended as factors to be considered when evaluating
possible sources of PAHs.
Abstract: Kurtbogazi Dam has gained special meaning for Ankara, Turkey for the last decade due to the rapid depletion of nearby resources of drinking water. In this study, the results of the analyses of Kurtbogazi Dam outlet water and the rivers flowing into the Kurtbogazi Dam were discussed for the period of last five years between 2008 and 2012. Some physical and chemical properties (pH, temperature, biochemical oxygen demand (BOD5), nitrate, phosphate and chlorine) of these water resources were evaluated. They were classified according to the Council Directive (75/440/EEC). Moreover, the properties of these surface waters were assessed to determine the quality of water for drinking and irrigation purposes using Piper, US Salinity Laboratory and Wilcox diagrams. The results showed that all the water resources are acceptable level as surface water except for Pazar Stream in terms of ortho-phosphate and BOD5 concentration for 2008.
Abstract: The development of composite materials and the
related design and manufacturing technologies is one of the most
important advances in the history of materials. Composites are
multifunctional materials having unprecedented mechanical and
physical properties that can be tailored to meet the requirements of a
particular application. Some composites also exhibit great resistance
to high-temperature corrosion, oxidation, and wear. Polymers are
widely used indoors and outdoors, therefore they are exposed to a
chemical environment which may include atmospheric oxygen, acidic
fumes, acidic rain, moisture heat and thermal shock, ultra-violet light,
high energy radiation, etc. Different polymers are affected differently
by these factors even though the amorphous polymers are more
sensitive. Ageing is also important and it is defined as the process of
deterioration of engineering materials resulting from the combined
effects of atmospheric radiation, heat, oxygen, water, microorganisms
and other atmospheric factors.
Abstract: This study aims at improving the urban hydrological
cycle of the Orléans agglomeration (France) and understanding the
relationship between physical and chemical parameters of urban
surface runoff and the hydrological conditions. In particular water
quality parameters such as pH, conductivity, total dissolved solids,
major dissolved cations and anions, and chemical and biological
oxygen demands were monitored for three types of urban water
discharges (wastewater treatment plant output (WWTP), storm
overflow and stormwater outfall) under two hydrologic scenarios (dry
and wet weather). The first results were obtained over a period of five
months. Each investigated (Ormes, l’Egoutier and La Corne) outfall
represents an urban runoff source that receives water from runoff
roads, gutters, the irrigation of gardens and other sources of flow over
the Earth’s surface that drains in its catchments and carries it to the
Loire River. In wet weather conditions there is rain water runoff and
an additional input from the roof gutters that have entered the
stormwater system during rainfall. For the comparison the results La
Chilesse is a storm overflow that was selected in our study as a
potential source of waste water which is located before the (WWTP). The comparison of the physical-chemical parameters (total
dissolved solids, turbidity, pH, conductivity, dissolved organic
carbon (DOC), concentration of major cations and anions) together
with the chemical oxygen demand (COD) and biological oxygen
demand (BOD) helped to characterize sources of runoff waters in the
different watersheds. It also helped to highlight the infiltration of
wastewater in some stormwater systems that reject directly in the
Loire River. The values of the conductivity measured in the outflow
of Ormes were always higher than those measured in the other two
outlets. The results showed a temporal variation for the Ormes outfall
of conductivity from 1465 μS cm-1 in the dry weather flow to 650 μS
cm-1 in the wet weather flow and also a spatial variation in the wet
weather flow from 650 μS cm-1 in the Ormes outfall to 281 μS cm-1
in L’Egouttier outfall. The ultimate BOD (BOD28) showed a
significant decrease in La Corne outfall from 181 mg L-1 in the wet
weather flow to 95 mg L-1 in the dry weather flow because of the
nutrient load that was transported by the runoff.
Abstract: Oxygen Reduction Reaction (ORR) performance of
iron and nitrogen co-doped porous carbon nanoparticles (Fe-NPC)
with various physical and (electro) chemical properties have been
investigated. Fe-NPC nanoparticles are synthesized via a facile
soft-templating procedure by using Iron (III) chloride hexa-hydrate as
iron precursor and aminophenol-formaldehyde resin as both carbon
and nitrogen precursor. Fe-NPC nanoparticles shows high surface area
(443.83 m2g-1), high pore volume (0.52 m3g-1), narrow mesopore size
distribution (ca. 3.8 nm), high conductivity (IG/ID=1.04), high kinetic
limiting current (11.71 mAcm-2) and more positive onset potential
(-0.106 V) compared to metal-free NPC nanoparticles (-0.295V)
which make it high efficient ORR metal-free catalysts in alkaline
solution. This study may pave the way of feasibly designing iron and
nitrogen containing carbon materials (Fe-N-C) for highly efficient
oxygen reduction electro-catalysis.
Abstract: Nitrification is essential to biological processes
designed to remove ammonia and/or total nitrogen. It removes excess
nitrogenous compound in wastewater which could be very toxic to
the aquatic fauna or cause serious imbalance of such aquatic
ecosystem. Efficient nitrification is linked to an in-depth knowledge
of the structure and dynamics of the nitrifying community structure
within the wastewater treatment systems. In this study, molecular
technique was employed for characterizing the microbial structure of
activated sludge [ammonia oxidizing bacteria (AOB) and nitrite
oxidizing bacteria (NOB)] in a municipal wastewater treatment with
intention of linking it to the plant efficiency. PCR based phylogenetic
analysis was also carried out. The average operating and
environmental parameters as well as specific nitrification rate of plant
was investigated during the study. During the investigation the average temperature was 23±1.5oC.
Other operational parameters such as mixed liquor suspended solids
and chemical oxygen demand inversely correlated with ammonia
removal. The dissolved oxygen level in the plant was constantly
lower than the optimum (between 0.24 and 1.267 mg/l) during this
study. The plant was treating wastewater with influent ammonia
concentration of 31.69 and 24.47 mg/L. The influent flow rates
(ML/Day) was 96.81 during period. The dominant nitrifiers include:
Nitrosomonas spp. Nitrobacter spp. and Nitrospira spp. The AOB
had correlation with nitrification efficiency and temperature. This
study shows that the specific ammonia oxidizing rate and the specific
nitrate formation rates can serve as good indicator of the plant overall
nitrification performance.
Abstract: This paper is aimed to study combustion characteristics
of low NOx burner using petroleum cokes as fuel. The petroleum coke,
which is produced through the oil refining process, is an attractive fuel
in terms of its high heating value and low price. But petroleum coke is
a challenging fuel because of its low volatile content, high sulfur and
nitrogen content, which give rise to undesirable emission
characteristics and low ignitability. Therefore, the research and
development regarding the petroleum coke burner is needed for
applying this industrial system. In this study, combustion and emission
characteristics of petroleum cokes burner are experimentally
investigated in an industrial steam boiler. The low NOx burner is
designed to control fuel and air mixing to achieve staged combustion,
which, in turn reduces both flame temperature and oxygen. Air
distribution ratio of triple staged air is optimized experimentally. The
result showed that NOx concentration is lowest when overfire air is
used, and the burner function at a fuel rich condition. That is, the
burner is operated at the equivalence ratio of 1.67 and overall
equivalence ratio including overfire air is kept 0.87.
Abstract: The present paper attempts to investigate the
prediction of air entrainment rate and aeration efficiency of a free
overfall jets issuing from a triangular sharp crested weir by using
regression based modelling. The empirical equations, Support vector
machine (polynomial and radial basis function) models and the linear
regression techniques were applied on the triangular sharp crested
weirs relating the air entrainment rate and the aeration efficiency to
the input parameters namely drop height, discharge, and vertex angle.
It was observed that there exists a good agreement between the
measured values and the values obtained using empirical equations,
Support vector machine (Polynomial and rbf) models and the linear
regression techniques. The test results demonstrated that the SVM
based (Poly & rbf) model also provided acceptable prediction of the
measured values with reasonable accuracy along with empirical
equations and linear regression techniques in modelling the air
entrainment rate and the aeration efficiency of a free overfall jets
issuing from triangular sharp crested weir. Further sensitivity analysis
has also been performed to study the impact of input parameter on the
output in terms of air entrainment rate and aeration efficiency.
Abstract: Below-knee amputees commonly experience
asymmetrical gait patterns. It is generally believed that ischemia is
related to the formation of pressure sores due to uneven distribution
of forces. Micro-vascular responses can reveal local malnutrition.
Changes in local skin blood supply under various external loading
conditions have been studied for a number of years. Radionuclide
clearance, photo-plethysmography, trans-cutaneous oxygen tension
along with other studies showed that the blood supply would be
influenced by the epidermal forces, and the rate and the amount of
blood supply would decrease with increased epidermal loads being
shear forces or normal forces. Several cases of socket designs were
investigated using Finite Element Model (FEM) and Design of
Experiment (DOE) to increase flexibility and minimize the pressure
at the limb/socket interface using ultra high molecular weight
polyethylene (UHMWPE) and polyamide 6 (PA6) or Duraform. The
pressure reliefs at designated areas where reducing thickness is
involved are seen to be critical in determination of amputees’ comfort
and are very important to clinical applications. Implementing a hole
between the Patellar Tendon (PT) and Distal Tibia (DT) would
decrease stiffness and increase prosthesis range of motion where
flexibility is needed. In addition, displacement and prosthetic energy
storage increased without compromising mechanical efficiency and
prosthetic design integrity.
Abstract: In order to obtain efficient pollutants removal in
small-scale wastewater treatment plants, uniform water flow has to be
achieved. The experimental setup, designed for treating high-load
wastewater (leachate), consists of two aerobic biological reactors and
a lamellar settler. Both biological tanks were aerated by using three
different types of aeration systems - perforated pipes, membrane air
diffusers and tube ceramic diffusers. The possibility of homogenizing
the water mass with each of the air diffusion systems was evaluated
comparatively. The oxygen concentration was determined by optical
sensors with data logging. The experimental data was analyzed
comparatively for all three different air dispersion systems aiming to
identify the oxygen concentration variation during different
operational conditions. The Oxygenation Capacity was calculated for
each of the three systems and used as performance and selection
parameter. The global mass transfer coefficients were also evaluated
as important tools in designing the aeration system. Even though
using the tubular porous diffusers leads to higher oxygen
concentration compared to the perforated pipe system (which
provides medium-sized bubbles in the aqueous solution), it doesn’t
achieve the threshold limit of 80% oxygen saturation in less than 30
minutes. The study has shown that the optimal solution for the
studied configuration was the radial air diffusers which ensure an
oxygen saturation of 80% in 20 minutes. An increment of the values
was identified when the air flow was increased.
Abstract: Industries produce millions of cubic meters of effluent
every year and the wastewater produced may be released into the
surrounding water bodies, treated on-site or at municipal treatment
plants. The determination of organic matter in the wastewater
generated is very important to avoid any negative effect on the
aquatic ecosystem. The scope of the present work is to assess the
physicochemical composition of the wastewater produced from one
of the brewery industry in South Africa. This is to estimate the
environmental impact of its discharge into the receiving water bodies
or the municipal treatment plant. The parameters monitored for the
quantitative analysis of brewery wastewater include biological
oxygen demand (BOD5), chemical oxygen demand (COD), total
suspended solids, volatile suspended solids, ammonia, total oxidized
nitrogen, nitrate, nitrite, phosphorus and alkalinity content. In
average, the COD concentration of the brewery effluent was 5340.97
mg/l with average pH values of 4.0 to 6.7. The BOD5 and the solids
content of the wastewater from the brewery industry were high. This
means that the effluent is very rich in organic content and its
discharge into the water bodies or the municipal treatment plant could
cause environmental pollution or damage the treatment plant. In
addition, there were variations in the wastewater composition
throughout the monitoring period. This might be as a result of
different activities that take place during the production process, as
well as the effects of peak period of beer production on the water
usage.
Abstract: The influence of physicochemical water quality
parameters on the abundance and diversity of caddisfly larvae was
studied in seven sampling stations in Mae Tao and Mae Ku
watersheds, Mae Sot District, Tak Province, northern Thailand. The
streams: MK2 and MK8 as reference site, and impacted streams
(MT1-MT5) were sampled bi-monthly during July 2011 to May
2012. A total of 4,584 individual of caddisfly larvae belonging to 10
family and 17 genera were found. The larvae of family
Hydropsychidae were the most abundance, followed by
Philopotamidae, Odontoceridae, and Leptoceridae, respectively. The
genus Cheumatopsyche, Hydropsyche, and Chimarra were the most
abundance genera in this study. Results of CCA ordination showed
the total dissolved solids, sulfate, water temperature, dissolved
oxygen and pH were the most important physicochemical factors to
affect distribution of caddisflies communities. Changes in the
caddisfly fauna may indicate changes in physicochemical factors
owing to agricultural pollution, urbanization, or other human
activities. Results revealed that the order Trichoptera, identified to
species or genus, can be potentially used to assess environmental
water quality status in freshwater ecosystems.
Abstract: Chalcopyrite (CuFeS2) is the most common primary
mineral used for the commercial production of copper. The low
dissolution efficiency of chalcopyrite in sulfate media has prevented
an efficient industrial leaching of this mineral in sulfate media. Ferric
ions, bacteria, oxygen and other oxidants have been used as oxidizing
agents in the leaching of chalcopyrite in sulfate and chloride media
under atmospheric or pressure leaching conditions. Two leaching
methods were studied to evaluate chalcopyrite (CuFeS2) dissolution
in acid media. First, the conventional oxidative acid leaching method
was carried out using sulfuric acid (H2SO4) and potassium
dichromate (K2Cr2O7) as oxidant at atmospheric pressure. Second,
microwave-assisted acid leaching was performed using the
microwave accelerated reaction system (MARS) for same reaction
media. Parameters affecting the copper extraction such as leaching
time, leaching temperature, concentration of H2SO4 and
concentration of K2Cr2O7 were investigated. The results of
conventional acid leaching experiments were compared to the
microwave leaching method. It was found that the copper extraction
obtained under high temperature and high concentrations of oxidant
with microwave leaching is higher than those obtained
conventionally. 81% copper extraction was obtained by the
conventional oxidative acid leaching method in 180 min, with the
concentration of 0.3 mol/L K2Cr2O7 in 0.5M H2SO4 at 50 ºC, while
93.5% copper extraction was obtained in 60 min with microwave
leaching method under same conditions.
Abstract: An experimental investigation is carried out to
establish the performance characteristics of a compression ignition
engine while using cerium oxide nanoparticles as additive in neat
diesel and diesel-biodiesel blends. In the first phase of the
experiments, stability of neat diesel and diesel-biodiesel fuel blends
with the addition of cerium oxide nanoparticles is analyzed. After
series of experiments, it is found that the blends subjected to high
speed blending followed by ultrasonic bath stabilization improves the
stability. In the second phase, performance characteristics are studied
using the stable fuel blends in a single cylinder four stroke engine
coupled with an electrical dynamometer and a data acquisition
system. The cerium oxide acts as an oxygen donating catalyst and
provides oxygen for combustion. The activation energy of cerium
oxide acts to burn off carbon deposits within the engine cylinder at
the wall temperature and prevents the deposition of non-polar
compounds on the cylinder wall results reduction in HC emissions.
The tests revealed that cerium oxide nanoparticles can be used as
additive in diesel and diesel-biodiesel blends to improve complete
combustion of the fuel significantly.
Abstract: Distillery spentwash contains high chemical oxygen
demand (COD), biological oxygen demand (BOD), color, total
dissolved solids (TDS) and other contaminants even after biological
treatment. The effluent can’t be discharged as such in the surface
water bodies or land without further treatment. Reverse osmosis (RO)
treatment plants have been installed in many of the distilleries at
tertiary level in many of the distilleries in India, but are not properly
working due to fouling problem which is caused by the presence of
high concentration of organic matter and other contaminants in
biologically treated spentwash. In order to make the membrane
treatment a proven and reliable technology, proper pre-treatment is
mandatory. In the present study, ultra-filtration (UF) for pretreatment
of RO at tertiary stage has been performed. Operating
parameters namely initial pH (pHo: 2–10), trans-membrane pressure
(TMP: 4-20 bars) and temperature (T: 15-43°C) were used for
conducting experiments with UF system. Experiments were
optimized at different operating parameters in terms of COD, color,
TDS and TOC removal by using response surface methodology
(RSM) with central composite design. The results showed that
removal of COD, color and TDS was 62%, 93.5% and 75.5%
respectively, with UF, at optimized conditions with increased
permeate flux from 17.5 l/m2/h (RO) to 38 l/m2/h (UF-RO). The
performance of the RO system was greatly improved both in term of
pollutant removal as well as water recovery.
Abstract: Sodium formate is the chemical substance used for
food additive. Catalase is the important antioxidative enzyme in
protecting the cell from oxidative damage by reactive oxygen species
(ROS). The resultant level of oxidative stress in sodium formatetreated
lymphocytes was investigated. The sodium formate
concentrations of 0.05, 0.1, 0.2, 0.4 and 0.6 mg/mL were treated in
human lymphocytes for 12 hours. After 12 treated hours, catalase
activity change was measured in sodium formate-treated
lymphocytes. The results showed that the sodium formate
concentrations of 0.4 and 0.6 mg/mL significantly decreased catalase
activities in lymphocytes (P < 0.05). The change of catalase activity
in sodium formate-treated lymphocytes may be the oxidative damage
marker for detect sodium formate exposure in human.
Abstract: Si ion implantation was widely used to synthesize
specimens of SiO2 containing supersaturated Si and subsequent high
temperature annealing induces the formation of embedded
luminescent Si nanocrystals. In this work, the potentialities of excimer
UV-light (172 nm, 7.2 eV) irradiation and rapid thermal annealing
(RTA) to enhance the photoluminescence and to achieve low
temperature formation of Si nanocrystals have been investigated. The
Si ions were introduced at acceleration energy of 180 keV to fluence of
7.5 x 1016 ions/cm2. The implanted samples were subsequently
irradiated with an excimer-UV lamp. After the process, the samples
were rapidly thermal annealed before furnace annealing (FA).
Photoluminescence spectra were measured at various stages at the
process. We found that the luminescence intensity is strongly
enhanced with excimer-UV irradiation and RTA. Moreover, effective
visible photoluminescence is found to be observed even after FA at
900 oC, only for specimens treated with excimer-UV lamp and RTA.
We also prepared specimens of Si nanocrystals embedded in a SiO2 by
reactive pulsed laser deposition (PLD) in an oxygen atmosphere. We
will make clear the similarities and differences with the way of
preparation.
Abstract: Waste Load Allocation (WLA) strategies usually
intend to find economic policies for water resource management.
Water quality trading (WQT) is an approach that uses discharge
permit market to reduce total environmental protection costs. This
primarily requires assigning discharge limits known as total
maximum daily loads (TMDLs). These are determined by monitoring
organizations with respect to the receiving water quality and
remediation capabilities. The purpose of this study is to compare two
approaches of TMDL assignment for WQT policy in small catchment
area of Haraz River, in north of Iran. At first, TMDLs are assigned
uniformly for the whole point sources to keep the concentrations of
BOD and dissolved oxygen (DO) at the standard level at checkpoint
(terminus point). This was simply simulated and controlled by
Qual2kw software. In the second scenario, TMDLs are assigned
using multi objective particle swarm optimization (MOPSO) method
in which the environmental violation at river basin and total treatment
costs are minimized simultaneously. In both scenarios, the equity
index and the WLA based on trading discharge permits (TDP) are
calculated. The comparative results showed that using economically
optimized TMDLs (2nd scenario) has slightly more cost savings rather
than uniform TMDL approach (1st scenario). The former annually
costs about 1 M$ while the latter is 1.15 M$. WQT can decrease
these annual costs to 0.9 and 1.1 M$, respectively. In other word,
these approaches may save 35 and 45% economically in comparison
with command and control policy. It means that using multi objective
decision support systems (DSS) may find more economical WLA,
however its outcome is not necessarily significant in comparison with
uniform TMDLs. This may be due to the similar impact factors of
dischargers in small catchments. Conversely, using uniform TMDLs
for WQT brings more equity that makes stakeholders not feel that
much envious of difference between TMDL and WQT allocation. In
addition, for this case, determination of TMDLs uniformly would be
much easier for monitoring. Consequently, uniform TMDL for TDP
market is recommended as a sustainable approach. However,
economical TMDLs can be used for larger watersheds.
Abstract: Due to the resultant leachate from waste
decomposition in landfills has polluter potential hundred times
greater than domestic sewage, this is considered a problem related to
the depreciation of environment requiring pre-disposal treatment.In
seeking to improve this situation, this project proposes the treatment
of landfill leachate using natural fibers intercropped with advanced
oxidation processes. The selected natural fibers were palm, coconut
and banana fiber.These materials give sustainability to the project
because, besides having adsorbent capacity, are often part of waste
discarded. The study was conducted in laboratory scale.In trials, the
effluents were characterized as Chemical Oxygen Demand (COD),
Turbidity and Color. The results indicate that is technically
promising since that there were extremely oxidative conditions, the
use of certain natural fibers in the reduction of pollutants in leachate
have been obtained results of COD removals between 67.9% and
90.9%, Turbidity between 88.0% and 99.7% and Color between
67.4% and 90.4%.The expectation generated is to continue evaluating
the association of efficiency of other natural fibers with other landfill
leachate treatment processes.