Fixed bed adsorption columns packed with natural zeolite were used to study the
kinetics of heavy metals removal from the single component solutions of Vanadium, Nikle,
Zinc, and Lead. The system parameters studied include solution flow rate and be
d height.
The effect of competing cations was also studied to establish the effectiveness of natural
zeolite in treating Industrial wastewater under continuous conditions using fixed bed
columns. The metal loaded natural zeolite was regenerated using NaCl . The results from
column studies showed that the Slower flow rates gave better removal efficiencies
compared to faster ones, Longer bed heights also resulted in greater adsorption
efficiencies. The bed depth service time (BDST) model was successfully used to simulate
experimental results at 30 % breakthrough. This model provides the necessary parameters
needed for fixed bed column design, the factor R2 ranged between 0.91 – 0.95. Natural
zeolite was exposed to 3 cycles of adsorption and desorption. The efficiency of the column
in removing heavy metals was high, The results indicate that natural zeolite can be
regenerated and re-used in removing heavy metals from solution.
The study was carried out on the sorption of heavy metals (Pb+2, Zn+2) under static
conditions from single- and multicomponent aqueous solutions by Syrian Zeolite mineral
extracted from south Syria. The removal has an ion-exchange nature and consis
ts of three
stages: the adsorption on the surface of microcrystals, the inversion stage, and the
moderate adsorption in the interior of the microcrystal, The study showed that equilibrium
time is 6 hours, and The slight difference between adsorption capacity of the Zeolite
toward lead, zinc from single- and multicomponent solutions may testify to individual
sorption centers of the zeolite for each metal. The maximum sorption capacity toward pb2+
is determined as 33.89 mg/g at an equilibrium concentration of 261.07 mg/L and toward
Zn+2 as 29.18 mg/g at 309.818 mg/L. Langmuir and Freundlich Adsorption Isotherms
were used to evaluate natural zeolite adsorption performance for Lead, Zinc. These
Isotherms were able to provide suitable fit with experimental data, the factor R2 ranged
between 0.95 – 0.99, with better fit to Langmuir Isotherm.
In this work, the performance of batch electrocoagulation (EC) treatment using iron
electrodes with monopolar and bipolar electrode configurations for trivalent chromium (Cr
(III)) removal from a synthetic wastewater was investigated. The influence
s of current
density (from 2 to 25 mA/cm2) and initial metal concentration (from 100 to 250 mg/L) on
the removal efficiency were explored in a batch stirred cell for monopolar and bipolar
configurations.
Removal of Cr (III) by EC process from aqueous solution with both monopolar and
bipolar electrode configurations was a feasible process. For the initial Cr (III)
concentration of 250 mg/L, almost complete removal (99.88%) of Cr (III) was noted after
20 min of EC in case of bipolar electrode arrangement at 25 mA/cm2 with 4.5 mmol/L of
supporting electrolyte (Na2SO4) against 89.58% of Cr (III) removal for monopole electrode
configuration.
At the same electrolysis time, the power consumption was 47 and 15.3 kWh/m3 in
case of monopolar and bipolar configuration respectively for the previous removal
conditions.
The study was carried out to remove of heavy metals (V+5, Ni+2)
under static conditions from aqueous solutions by Syrian Zeolite
mineral extracted from south of Syria. The results revealed that
operational conditions such as initial solution pH and concentration,
adsorbent particle size, the presence of competing cations, are able
to affect the adsorption capacity and efficiency of natural zeolite.
The activated sludge is one of the most common methods of sewage treatment , which has been studied through to find the relation between sedimentation properties and the performance of aeration units. sedimentation experiments were applied on a highl
y- aerated activated sludge experimental treatment plant .Also, another experiments were applied on Marj Maerban treatment plant which is operated using the extended aeration method in order to find the Factors influencing the settling of activated sludge . These experiments were done using the Sludge volume index (SVI) ,the maximum velocity sedimentation rate (UMAX) and the time corresponding to the maximum velocity of sedimentation (TUMAX).In experimental treatment plant. We found that the sedimentation experimental parameters (Vo, n) are very sensitive and can be changed significantly with changing the values of suspended solids (MLSS) in the aeration tank. The mathematical relationships can be used to predict the value of (Vo, n) as well as designing and selecting the operating system of sludge without resorting to a conventional sedimentation tests . We also found in the extended aeration the maximum velocity sedimentation rate (UMAX) is the most important in settling process as we got some good correlation coefficients (R2) between UMAX and (TUMAX, MLSS, SVI) was at a temperature (20OC) were respectively (98, 96,98%), and when the temperature (17 OC) respectively (97,96,97%) which is almost the same values. We noticed that the sludge volume index (SVI) is closely associated with the settling parameters (UMAX, TUMAX) with the correlation coefficients were respectively (98,99%) on the temperature of (20OC) and (98,97%) on the temperature of (17OC) . Velocity sedimentation rate (UMAX) was the largest and deposition time (TUMAX) was smaller on the temperature of (20OC) Indicating an improved sedimentation with higher temperatures . Subsequently, temperature is an influential factor on deposition and It is necessary to be taken into account in the design and operation of activated sludge treatment plan.
This research includes monitoring the distribution of DO concentrations in the Marj Maarban and AL Ruyemih WWTPs which use different types of aeration systems (surface aerators and diffusers). Research has shown a remarkable increase in the values of
DO concentrations in the studied aeration basins above 2 mg/l which means an increased electricity consumption and operational problems, in addition to the role of the natural aeration process in reducing the number of aerators operation hours. This will reflect positively on the performance of the plant and the investment cost.
This study was performed at three plants for sewage treatment in Syrian coastal
villages: al-Hara, Murj-Muairban, and Hibbeat. Dry sludge samples were collected from
drying sludge basins monthly, during the period October 2011-September 2012. We
d
epended on different global ways to isolate the eggs from the sludge (flotation,
sedimentation, filtration through special sieves).
The microscopic study results of the sediment showed the presence of 5 different
species of the parasitic worm-eggs, belonged taxonomically to five different species of
parasitic worms, two species belonged to Nematoda: Ascaris lumbricoides and Trichuris
trichura, and three species belonged to Platyhelminthes: one species of them belonged to
Trematoda: Schistosoma mansoni, and the other two species belonged to cestodes: Taenia
saginata, and Diphyllobothrium latum.
The average number of worms eggs isolated from the dry sludge resulting from the
three studied sewage treatment plants (al-Hara, Murj-Muairban, and Hibbeat) recorded
relatively close values, the most number in the dry sludge resulting from the treatment
plant in Hibbeat with an average 97.16% eggs/50g, then al-Hara with an average
75.08egg/50g dry sludge. Also the results showed that the isolated eggs were more
diversed in Hibbeat treatment plant, this an indicator of the health status of the population
in the studied sites.
Study showed that the number and diversity of parasitic worm – eggs use more
observed in Summer and Autumn than in Winter and Spring.
As a result of increased environmental awareness and interest in the effective protection
of the environment from pollution, the restrictions have increased on the disposal of
wastewater, and the need to the treatment plants has arisen to treat the
wastewater prior to
disposal in water bodies, whether water from either large or small communities. As a result of
the importance of these facilities and cost of material massive construction, operation and
maintenance. In order to facilitate the design process and calculate the initial cost it was issued
some software that helps engineer in the design of the various parts of the station, and in order
to choose the equipments and comparison between several alternatives in objective ways to
choose the most appropriate. Some of these programs are dynamics. It has the ability to
simulate the work of the treatment plant along the time and predict its efficiency and
performance. STOAT is a software that aims to model and simulate wastewater and industrial
wastewater treatment plant, and it is one of the newest technology that uses the latest
developments in process modelling, simulation and a wide range of tools that simplifies the
model building and simulation and give the results in graphics and tables, allowing us to
examine the complex interactions between the various units within the station by interactive
and dynamic methods and this is important for the effective design, operation and management
of wastewater treatment plants. Hence, we take the coastal area as a case study where there are
number of modern wastewater treatment plants of small agglomeration and is being work, as
Kherbet al-Maaze wastewater treatment plant in Tartous. Using STOAT, the study shows a
good efficiency and performance of Kherbet al-Maaze WWTP using (ASM1,ASAL1) models,
and we could build several scenarios like arrival of high pollution load to the station in order to
evaluate and predict its performance.
The aim of this study is to investigate the performance of batch electro coagulation (EC) using iron electrodes with bipolar configuration for simultaneous removal of chromium (Cr3+) from synthetic wastewater. The influences of current density (from
2 to 25 mA/cm2), initial metal concentration (from 100 to 250 mg/L) and supporting electrolyte (0-12 mmol/L Na2SO4) on removal efficiency are explored in a batch stirred cell to determine the best experimental conditions.
The results indicate that EC was very efficient to remove Cr3+ from the synthetic wastewater having an initial concentration of 250 mg/L of Cr3+ under the best experimental conditions. At the current density of 15 mA/cm2 with a total energy consumption of ∼18.5 kWh/m3, more
than 98.7% removal value was achieved for Cr3+ after 20 min EC treatment. Time of 20 minutes EC treatment was chosen as optimum time to gain less than 4 mg Fe/L in the treated water.
This study aims to determine the concentrations of some heavy metals that are present in the crude oil and in liquid waste of the crude oil desalting unit .The extraction method (liquid-solid) is used for concentrating and extraction these compounds
from the
saltwater samples .Samples were collected from the unit’s discharging points and from the subsequent treatment stages .A suitable analytical method was used to extract these metals
from both of crude oil and the oil refineries᾿ liquid wastes.
The objective of this study is to observe the fate of these wastes from the discharging points of desalting unit and through physical – chemical – biological treatment stages and dawn to the receiving water (Mediterranean sea). The results showed that Syrian crude oil contains a combination of heavy metals which includes : (Vanadium – Nickel – Iron – Zinc – Manganese – Copper – Cadmium – Lead - Chromium and Cobalt) .Vanadium showed the highest concentration followed by Nickel and Iron subsequently ,the total efficiency of the treatment plant achieved the following efficiencies : 41.06% (Vanadium), 44.92% (Nickel) and 39.34% ( Iron) ,then the concentration of these discharges where compared with those in marine system to show the possible adverse effects of these compounds on the surrounding biosphere.
