Abstract: In this study, the dispersed model is used to predict
gas phase concentration, liquid drop concentration. The venturi
scrubber efficiency is calculated by gas phase concentration. The
modified model has been validated with available experimental data
of Johnstone, Field and Tasler for a range of throat gas velocities,
liquid to gas ratios and particle diameters and is used to study the
effect of some design parameters on collection efficiency.
Abstract: Nowadays, several techniques such as; Fuzzy
Inference System (FIS) and Neural Network (NN) are employed for
developing of the predictive models to estimate parameters of water
quality. The main objective of this study is to compare between the
predictive ability of the Adaptive Neuro-Fuzzy Inference System
(ANFIS) model and Artificial Neural Network (ANN) model to
estimate the Biochemical Oxygen Demand (BOD) on data from 11
sampling sites of Saen Saep canal in Bangkok, Thailand. The data is
obtained from the Department of Drainage and Sewerage, Bangkok
Metropolitan Administration, during 2004-2011. The five parameters
of water quality namely Dissolved Oxygen (DO), Chemical Oxygen
Demand (COD), Ammonia Nitrogen (NH3N), Nitrate Nitrogen
(NO3N), and Total Coliform bacteria (T-coliform) are used as the
input of the models. These water quality indices affect the
biochemical oxygen demand. The experimental results indicate that
the ANN model provides a higher correlation coefficient (R=0.73)
and a lower root mean square error (RMSE=4.53) than the
corresponding ANFIS model.
Abstract: The research study is carried out to determine the efficiency of the Biofilm sewage treatment plant which is located at the Engineering Complex-s. Wastewater analyses have been carried out at the Environmental Engineering laboratory to study the six parameters: Biochemical Oxygen Demand BOD, Chemical Oxygen Demand COD l, and Total Suspended Solids TSS, Ammoniac Nitrogen NH3-N and Phosphorous P which have been selected to determine the wastewater quality. The plant was designed to treat 750 Pe (population equivalent) at hydraulic retention time of 5 hours in the aerobic zone. The results show that Biofilm wastewater treatment plant was able to treat sewage successfully at different flow condition. The discharge has fulfilled the Malaysia Environmental of Standard A water quality. The achieved BOD removal is more than 85%, COD is more than 80%, TSS is more than 80%, NH3-N is more than 70%, and P was more than 70%. The Biofilm system provides a very efficient process for sewage treatment and it is compact in structure thus minimizes the required land area.
Abstract: 17α-ethynylestradiol (EE2) is a synthetic estrogen
used as a key ingredient in an oral contraceptives pill. EE2 is an
endocrine disrupting compound, high in estrogenic potency.
Although EE2 exhibits low degree of biodegradability with common
microorganisms in wastewater treatment plants (WWTPs), this
compound can be biotransformed by ammonia-oxidizing bacteria
(AOB) via a co-metabolism mechanism in WWTPs. This study
aimed to investigate the effect of real wastewater on
biotransformation of EE2 by AOB. A preliminary experiment on the
effect of nitrite and pH levels on abiotic transformation of EE2
suggested that the abiotic transformation occurred at only pH
Abstract: The solvated electron is self-trapped (polaron) owing
to strong interaction with the quantum polarization field. If the
electron and quantum field are strongly coupled then the collective
localized state of the field and quasi-particle is formed. In such a
formation the electron motion is rather intricate. On the one hand the
electron oscillated within a rather deep polarization potential well
and undergoes the optical transitions, and on the other, it moves
together with the center of inertia of the system and participates in
the thermal random walk. The problem is to separate these motions
correctly, rigorously taking into account the conservation laws. This
can be conveniently done using Bogolyubov-Tyablikov method of
canonical transformation to the collective coordinates. This
transformation removes the translational degeneracy and allows one
to develop the successive approximation algorithm for the energy and
wave function while simultaneously fulfilling the law of conservation
of total momentum of the system. The resulting equations determine
the electron transitions and depend explicitly on the translational
velocity of the quasi-particle as whole. The frequency of optical
transition is calculated for the solvated electron in ammonia, and an
estimate is made for the thermal-induced spectral bandwidth.
Abstract: Biological treatment of secondary effluent wastewater
by two combined denitrification/oxic filtration systems packed with
Lock type(denitrification filter) and ceramic ball (oxic filter) has been
studied for 5months. Two phases of operating conditions were carried
out with an influent nitrate and ammonia concentrations varied from
5.8 to 11.7mg/L and 5.4 to 12.4mg/L,respectively.
Denitrification/oxic filter treatment system were operated under an
EBCT (Empty Bed Contact Time) of 4h at system recirculation ratio in
the range from 0 to 300% (Linear Velocity increased 19.5m/d to
78m/d). The system efficiency of denitrification , nitrification over
95% respectively. Total nitrogen and COD removal range from
54.6%(recirculation 0%) to 92.3%(recirculation 300%) and 10% to
62.5%, respectively.
Abstract: Water hyacinth has been used in aquatic systems for
wastewater purification in many years worldwide. The role of water
hyacinth (Eichhornia crassipes) species in polishing nitrate and
phosphorus concentration from municipal wastewater treatment plant
effluent by phytoremediation method was evaluated. The objective
of this project is to determine the removal efficiency of water
hyacinth in polishing nitrate and phosphorus, as well as chemical
oxygen demand (COD) and ammonia. Water hyacinth is considered
as the most efficient aquatic plant used in removing vast range of
pollutants such as organic matters, nutrients and heavy metals. Water
hyacinth, also referred as macrophytes, were cultivated in the
treatment house in a reactor tank of approximately 90(L) x 40(W) x
25(H) in dimension and built with three compartments. Three water
hyacinths were placed in each compartments and water sample in
each compartment were collected in every two days. The plant
observation was conducted by weight measurement, plant uptake and
new young shoot development. Water hyacinth effectively removed
approximately 49% of COD, 81% of ammonia, 67% of phosphorus
and 92% of nitrate. It also showed significant growth rate at starting
from day 6 with 0.33 shoot/day and they kept developing up to 0.38
shoot/day at the end of day 24. From the studies conducted, it was
proved that water hyacinth is capable of polishing the effluent of
municipal wastewater which contains undesirable amount of nitrate
and phosphorus concentration.
Abstract: This paper presents the results of preliminary
assessment of water quality along the coastal areas in the vicinity of
Left Bank Outfall Drainage (LBOD) and Tidal Link Drain (TLD) in
Sindh province after the cyclone 2A occurred in 1999. The water
samples were collected from various RDs of Tidal Link Drain and
lakes during September 2001 to April 2002 and were analysed for
salinity, nitrite, phosphate, ammonia, silicate and suspended material
in water. The results of the study showed considerable variations in
water quality depending upon the location along the coast in the
vicinity of LBOD and RDs. The salinity ranged between 4.39–65.25
ppt in Tidal Link Drain samples whereas 2.4–38.05 ppt in samples
collected from lakes. The values of suspended material at various
RDs of Tidal Link Drain ranged between 56.6–2134 ppm and at the
lakes between 68–297 ppm. The data of continuous monitoring at
RD–93 showed the range of PO4 (8.6–25.2 μg/l), SiO3 (554.96–1462
μg/l), NO2 (0.557.2–25.2 μg/l) and NH3 (9.38–23.62 μg/l). The
concentration of nutrients in water samples collected from different
RDs was found in the range of PO4 (10.85 to 11.47 μg/l), SiO3 (1624
to 2635.08 μg/l), NO2 (20.38 to 44.8 μg/l) and NH3 (24.08 to 26.6
μg/l). Sindh coastal areas which situated at the north-western
boundary the Arabian Sea are highly vulnerable to flood damages
due to flash floods during SW monsoon or impact of sea level rise
and storm surges coupled with cyclones passing through Arabian Sea
along Pakistan coast. It is hoped that the obtained data in this study
would act as a database for future investigations and monitoring of
LBOD and Tidal Link Drain coastal waters.
Abstract: The aim of this study was to investigate ammonium
exchange capacity of natural and activated clinoptilolite from
Kwazulu-Natal Province, South Africa. X – ray fluorescence (XRF)
analysis showed that the clinoptilolite contained exchangeable ions
of sodium, potassium, calcium and magnesium. This analysis also
confirmed that the zeolite sample had a high silicon composition
compared to aluminium. Batch equilibrium studies were performed
in an orbital shaker and the data fitted the Langmuir isotherm very
well. The ammonium exchange capacity was found to increase with
pH and temperature. Clinoptilolite functionalization with
hydrochloric acid increased its ammonia uptake ability.
Abstract: In this study, a low temperature sensor highly selective to CO in presence of methane is fabricated by using 4 nm SnO2 quantum dots (QDs) prepared by sonication assisted precipitation. SnCl4 aqueous solution was precipitated by ammonia under sonication, which continued for 2 h. A part of the sample was then dried and calcined at 400°C for 1.5 h and characterized by XRD and BET. The average particle size and the specific surface area of the SnO2 QDs as well as their sensing properties were compared with the SnO2 nano-particles which were prepared by conventional sol-gel method. The BET surface area of sonochemically as-prepared product and the one calcined at 400°C after 1.5 hr are 257 m2/gr and 212 m2/gr respectively while the specific surface area for SnO2 nanoparticles prepared by conventional sol-gel method is about 80m2/gr. XRD spectra revealed pure crystalline phase of SnO2 is formed for both as-prepared and calcined samples of SnO2 QDs. However, for the sample prepared by sol-gel method and calcined at 400°C SnO crystals are detected along with those of SnO2. Quantum dots of SnO2 show exceedingly high sensitivity to CO with different concentrations of 100, 300 and 1000 ppm in whole range of temperature (25- 350°C). At 50°C a sensitivity of 27 was obtained for 1000 ppm CO, which increases to a maximum of 147 when the temperature rises to 225°C and then drops off while the maximum sensitivity for the SnO2 sample prepared by the sol-gel method was obtained at 300°C with the amount of 47.2. At the same time no sensitivity to methane is observed in whole range of temperatures for SnO2 QDs. The response and recovery times of the sensor sharply decreases with temperature, while the high selectivity to CO does not deteriorate.
Abstract: A study was undertaken to assess the potential of an
Algal Turf Scrubber to remove nitrogen from aquaculture effluent to
reduce environmental pollution. High total ammonia nitrogen
concentrations were introduced to an Algal Turf Scrubber developed
under varying hydraulic surface loading rates of African catfish
(Clarius gariepinus) effluent in a recirculating aquaculture system.
Nutrient removal rates were not affected at total suspended solids
concentration of up to 0.04g TSS/l (P > 0.05). Nitrogen removal
rates 0.93-0.99g TAN/m²/d were recorded at very high loading rates
3.76-3.81 g TAN/m²/d. Total ammonia removal showed ½ order
kinetics between 1.6 to 2.3mg/l Total Ammonia Nitrogen
concentrations. Nitrogen removal increased with its loading, which
increased with hydraulic surface loading rate. Total Ammonia
Nitrogen removal by Algal turf scrubber was higher than reported
values for fluidized bed filters and trickling filters. The algal turf
scrubber also effectively removed nitrate thereby reducing the need
for water exchange.
Abstract: Biological Ammonia removal (nitrification), the
oxidation of ammonia to nitrate catalyzed by bacteria, is a key part of
global nitrogen cycling. In the first step of nitrification,
chemolithoautotrophic ammonia oxidizer transform ammonia to
nitrite, this subsequently oxidized to nitrate by nitrite oxidizing
bacteria. This process can be affected by several factors. In this study
the effect of influent COD on biological ammonia removal in a
bench-scale biological reactor was investigated. Experiments were
carried out using synthetic wastewater. The initial ammonium
concentration was 25mgNH4
+-N L-1. The effect of COD between
247.55±1.8 and 601.08±3.24mgL-1 on biological ammonia removal
was investigated by varying the COD loading supplied to reactor.
From the results obtained in this study it could be concluded in the
range of 247.55±1.8 to 351.35±2.05mgL-1, there is a direct
relationship between amount of COD and ammonia removal.
However more than 351.35±2.05 up to 601.08±3.24mgL-1 were
found an indirect relationship between them.