Showing 29 results for Jafari
F Rashid Ashmagh, R Rezaei Kalantary, M Farzadkia, A Joneidy Jafari, R Nabizadeh,
Volume 2, Issue 3 (25 2009)
Abstract
Backgrounds and Objectives: Polycyclic aromatic hydrocarbons (PAHs) are a group of hazardous pollutants which have carcinogenic and mutagenic properties and accumulated in environment by different actions, therefore treatment of them is important. Biological treatments are simple and cheep technologies. This technology was recommended as a cost- effective method for treatment of these pollutants. In order to investigate the trend of pollution reduction of petroleum hydrocarbons in bioremediation, the phenanthrene biodegradation&aposs model in contaminated soils was studied.
Materials and Methods: Firstly, PAHs capable degrading bacteria was isolated from petroleum contaminated soils and then their ability for biodegradation of phenanthrene was assessed in slurry phase. After that by using Acinetobacter which have the most potential of removing phenanthrene from soil, the biodegradation model was investigated in bench scale.
Results: Phenantherene removal efficiency was obtained 99.4% for 100 mg/kg and 96 % for 500 mg/kg concentrations in 33 and 60 days biodegradation period respectively. Phenantherene reduction rate varied from 2.99 to 8.86 and 1.4 to 11.09 mg/kg/day for 100 and 500 mg/kg concentrations, respectively.
Conclusion: Rate of phenantherene removal is depended on primary concentration of contamination and by increasing of primary concentration, phenantherene removal rate was increased. Also removal efficiency followed zero and first order kinetic model with good correlation.
M Farzadkia, S Salehi, A Aameri, A Joneidy Jafari, R Nabizadeh,
Volume 2, Issue 3 (25 2009)
Abstract
Backgrounds and Objectives: Over than 70% of solid wastes is consisted of food wastes with high putrecibility in Iran. Due to this regard, construction of composting factories for sanitary disposal or fertilizer production from solid wastes was very appreciated in our country. The objective of this research was to study on the quality and comparing of the compost produced by Khomain and Tehran compost factories.
Materials and Methods: This study was accomplished on the compost produce from Khomain and Tehran compost factories about 9 months. For investigation of chemical qualities of these materials, some indexes such as percentage of organic materials, carbon, nitrogen, phosphorus, potash and heavy metals consists of lead, cadmium, mercury and chromium were measured. Microbial quality of these compost materials were defined by assessing of the amounts of coliforms bacteria, salmonella bacteria and parasites ova.
Results: The average amounts of some indexes in compost of Khomain and Tehran were been: organic materials % (37.77, 29.80), carbon %( 22.14, 18.12), nitrogen% (2.08, 1.6), lead (229.6, 59.44 ppm), and chromium (70.2, 19.75), respectively. The microbial quality of these compost samples were agreement with class B of USEPA guidelines.
Conclusion: This study showed that quality of organic materials percent in Tehran's samples was better than Khomain's samples, but these indexes on these samples were lower than the grade No.2 of compost. The percentage of carbon, nitrogen and potash in these samples were desirable but, phosphorus amount were not in sufficient. The heavy metals especially lead and chromium in Tehran's samples were higher than Khomain's samples, but these samples were usually in agreement with guidelines of compost. Due to the defined microbial qualities, these samples could be used as well as amendment agents for poor soil.
P Bahmani, R Rezaei Kalantary, M Gholami, A Jonidi Jafari, Z Javadi,
Volume 3, Issue 4 (8 2011)
Abstract
Backgrounds and Objectives: Reactive dyestuff has potential of toxicity, carcinogenesis and mutagenesis for mammals and aquatic organisms. The current physical and chemical methods such as adsorption, coagulation, precipitation, filtration and ... can been used for removing of dyestuff. Biological treatment which is effective and economic for decontamination of dyestuff wastewaters was preferred because of limitation and difficulty of physicochemical methods. In order to investigate the trend of pollution reduction of color compounds, ability of Remazol Black-B dyestuff removal from aqueous medium by bacterial consortium under anoxic conditions was studied.
Materials and Methods: The mix culture of bacteria from textile industries activated sludge was enriched in luria broth medium containing RB-B dyestuff as a carbon source. Then biodegradation was assessed in 4 batch reactors. Microbial population of bacterial and decolorization quantities of samples were detected by MPN and UV-Vis spectrophotometer.
Results: Decolorization efficiency by the bacterial consortium was obtained more than 99% for 50 and 250 mg/L concentrations in 72 and 144 h (3 and 6 days) respectively, while for the initial concentration of 500 mg/L was 98.1in 240 h (10 days) of biodegradation period. Dyestuff reduction rate after completed removal was about 0.69, 1.74,2 mg/L/h for initial concentration of 50, 250, 500 mg/L respectively.
Conclusion: Results showed that Alcaligenes denitrificans and Alcaligenes xylosoxidans bacteria
which were isolated from activated sludge have good potential of RB-B dyestuff removal and this removal is depending on primary concentration of dye. Removal efficiency increased as primary concentration went up.
A Dalvand, A Jonidi Jafari, M Gholami, A Ameri, N.m Mahmoodi,
Volume 4, Issue 1 (24 2011)
Abstract
Background and Objectives: Discharge of textile colored wastewater industries without providing enough treatment in water bodies, is harmful for human and aquatic organisms and poses serious damages to the environment. Most of conventional wastewater treatment methods don't have enough efficiency to remove textile dyes from colored wastewater thus in this research the efficiency of electrocoagulation treatment process with aluminum electrodes for treatment of a synthetic wastewater containing C.I. Reactive Red 198 in batch reactor was studied.
Material and Methods: The experiment conducted in a Plexiglas reactor with a working volume of 2L that equipped with 4 aluminum electrodes. The effects of operating parameters such as voltage, time of reaction, initial dye concentration and interelectrode distance on the color removal efficiency, electrical energy consumption and electrode consumption were investigated.
Results: in the optimum operational condition electrocoagulation, is able to remove color and COD as high as 99.1 and 84.3% in aluminum electrode in 75 minutes at 20 volt and 2 cm interelectrode distance, respectively. Under this condition, operating cost was 2986 rails per cubic meter of treated wastewater. Increase in the interelectrode distance and initial dye concentration,lead to the decrease in efficiency of dye and COD removal.While as the voltage and time of reaction increased, energy consumption, electrode consumption, final pH and color removal, increased too.
Conclusion: electrocoagulation process by aluminum electrode is an efficient and suitable method for reactive dye removal from colored wastewater.
A Rezaee, G Kashi, A Jonidi Jafari, A.r Khataee,
Volume 4, Issue 2 (9 2011)
Abstract
Background and objective: The conventional chemical and physical methods for water disinfection include the application of ultraviolet (UV), chlorination, and ozonation. Water disinfection by electrochemical methods has been increasingly carried out recently. The goal of this applied - analytical research is to investigate the removal of E. coli bacteria, as the index of water microbial contamination, from drinking water by electrochemistry method.
Materials and Methods: In this study, the contaminated water sample was prepared through adding 102 and 103 E. coli bacteria per ml of drinking water. The contaminated water entered into the electrochemical reactor and different conditions were studied, included pH (6, 7, and 8), number of bacterium (102 and 103 per milliliter), time (5, 10, 20, and 40 min), distance between electrodes (2,2.5, 3, and 3.5 cm), and voltage (10, 20, 30, and 40 volts).
Results: The findings indicated the indirect correlation between bacteria removal efficiency and the variable distances between two electrode. The results indicated the direct correlation between bacteria removal efficiency and the variables voltage and electrolysis times. The results showed that the best conditions for removal of 102 and 103 bacteria per milliliter obtained at pH 7, electrolysis time of 10 min, distance between electrodes 2 cm, in the voltage 20 and 30 volts, respectively.
Conclusion: The results of this study indicate that voltage and electrolysis time have the most significant effect on electrolysis efficiency. Research findings showed that electrolysis is a promising method for removal of E. coli bacterium from drinking water.
R Noori, F Jafari, D Forman Asgharzadeh, A Akbarzadeh,
Volume 4, Issue 2 (9 2011)
Abstract
Backgrounds and Objectives: The Atrak River is an important water supply resource in the Razavi Khorasan, Northern Khorasan and Golestan provinces. This river is the line border of Iran and Turkistan countries. Unfortunately, lack of water quality and quantity data due to nonexistence of a proper surface water quality monitoring station network is one of the main problems for water quality evaluation in the Atrak River. The main objective of the research is to offer a proper framework for surface water quality evaluation regarding to the mentioned limitations.
Materials and Method: In the first step, proper surface water quality monitoring stations along Atrak River are selected and water quality conditions are indicated using water quality index (WQI) model. The second step is allocated for determining trophic states of the river. Finally, the river water quality modeling is carried out for one of the most important index of water quality in the Atrak River i.e. total dissolved solids (TDS) based on proposed method by Oconnor (1976).
Result: Results of WQI model showed that most of the stations were in the moderate class. The result also showed that most parts of this river had trophic condition. Finally, based on findings of O'Conor model it is demonstrated that the salinity status observed in these four stations originated from the base flow and therefore, salinity is affected by the natural sources.
Conclusion: This methodology in the research can be used in rivers which don't have the proper surface water quality monitoring stations and therefore encountered with lack of water quality data. It can provide the proper strategy and management tasks to reach the good water quality conditions.
Ruhollah Rostami, Ahmad Jonidi Jafari, Roshanak Rezaee Kalantari, Mitra Gholami,
Volume 5, Issue 1 (6 2012)
Abstract
Normal
0
false
false
false
EN-US
X-NONE
AR-SA
MicrosoftInternetExplorer4 Background and Objectives:Benzene,
toluene and Xylenes (BTX) are organic pollutants, which are mainly associated
with oil and its derivatives. BTX is environmental contaminants and considered
harmful to human health. Application of surface absorbents such as zeolite is
one of several methods for the removal of these compounds. In this study,
BTX compounds'
removal efficiencies were
investigated and compared by using
clinoptilolite
type zeolite
and zeolite
with copper
oxide nanoparticles.
Materials
and Methods: In this study, the modified zeolite by
hydrochloric acid in the grain size 1-2 mm and modified zeolite with nano
particle of copper oxide were used. Artificially- Contaminated Air
flow was used
continuously .To determine
BTX concentrations,
samplings were done by charcoal tube in
current input and output. The
concentrations of contaminants were determined by gas chromatography with FID
detector.
Results: Removal efficiency of benzene,
toluene, p-xylene, m-xylene and o-xylene by clinoptilolite were 78.3%, 62.1%,
32.2% 32.15% and 18.8%, respectively. For the clinoptilolite
containing copper oxide nano particles efficiency were 25.42%, 35.65%, 36.33%,
33.24% and 29.39%, respectively. Average removal efficiency of BTX compounds
observed when the zeolite without nanoparticles used (43.31%) was more than
zeolite with nanoparticles (32%). The results showed that the concentration of
CO2 in the outlet air of the zeolite-containing nanoparticle (550
ppm) was more than the zeolite without nanoparticle (525 ppm).
Conclusion: Results showed that adding nanoparticles to the
zeolite, although the removal efficiency of benzene and toluene
can be reduced.
The results showed that adding
nanoparticles to the zeolite, although can be reduced removal efficiency of
benzene and toluene, which may be due to occupying or blocking of the pollution
absorption sites by the nanoparticles on the zeolite, but It cause promote more
catalytic effect of zeolite in the decomposition process of contaminants by
breaking the molecules of pollutants and their further degradation progress is
done for conversion to carbon dioxide
Emad Dehghani Fard, Ahmad Jonidi Jafari, Roshanak Rezae Kalantari, Mitra Gholami, Ali Esrafili,
Volume 5, Issue 2 (13 2012)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Aniline has been used in different processes of chemical
industries, however due to its side effects on the environment, several methods
have been considered for its removal. In this study, we evaluated the
performance of photocatalytic process using ZnO nanoparticles (nZnO) and
ultraviolet (UV) irradiation for removal of Aniline from a synthetic effluent.
Materials and Methods: A 5L photocatalytic reactor made from Plexiglas, which the UV lamp (20w)
installed in the center of that (inside a quartz jacket), was designed and nZnO
(0.2-0.5 g/l) was being added into synthetic effluent with Aniline concentration
of 250 ppm. After retention times of 30, 60, and 90 min, samples were
centrifuged and supernatant was filtered using a 0.2 µ PTFE filter. The
liquid-liquid method and Gas Chromatography instrument was used for extraction
and analysis respectively.
Results: Results
showed that the photocatalytic process of nZnO+UV could effectively remove
Aniline from effluent. Increasing trend in the removal efficiency of Aniline
using nZnO = 0.5 g/l was slower in comparison with other nZnO concentrations
and the ANOVA analysis shows no significant difference between removal
efficiency of Aniline in different concentrations of nZnO. The most removal
efficiency of Aniline (76.3%) was observed in alkaline pH, retention time of 90
min and nZnO of 0.5 g/l.
Conclusion: It could be concluded that the
photocatalytic process of nZnO+UV could be suitable technique for Aniline
removal from effluents.
Omol Banin Naeej, Anoushiravan Mohseni Bandpi, Ahmad Jonidi Jafari, Ali Esrafili, Roshanak Rezaei Kalantary,
Volume 5, Issue 3 (21 2012)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Nitrate is one of the most groundwater pollutants in world.
Reduction of nitrate to nitrite by microorganisms cause serious health hazards.
Nitrate can be eliminated using either adsorbtion or reduction. In this study,
we investigated the adsorption of nitate on zeolite and the feasibility of
removal improvement using supported zero
valent nano iron on zeolite via the reduction process.
Materials and Methods: The study was done in two phases investigation the
zeolite and modified zeolite with zero valent nano iron in nitrate removal from
water. First, we determined the optimum pH and time then the effect of
adsorbent and nitrate concentration was investigated in one factor at the time.
The adsorption isotherm was calculated according to the optimum condition. The
physical characteristics of adsorbents were determined using SEM and TEM.
Results: The morphology investigation of adsorbent showed that the
particle size of supported zero valent nano iron on zeolite was approximately
30-50 nm in diameter. The best conditions were pH 5, contact time of 120 min
and 15 g/L for zeolite, while pH 3, contact time of 50 min and 7.5 g/L for
supported zero valent nano iron on
zeolite. The isotherm equations revealed that nitrate adsorption follows
Langmiur in both cases.
Conclusion: The supported zero
valent nano iron on zeolite could be considered as a high potential adsorbent
for nitrate because it has several adsorbent sites, and Fe
0 as a
function for nitrate reduction.
Somayeh Golbaz, Ahmad Jonidi Jafari, Roshanak Rezaei Kalantari,
Volume 5, Issue 4 (15 2013)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Cyanide is a toxic pollutant existing in the various
industrial effluents such as iron and steel, coal mining, non-ferrous metals
manufacturing and metal plating. Its presence in water resources and
wastewater, as serious hazardous substances leads to undesirable effects on
both the environment and human. Thus, its concentration control is essential
for human health. The main goal of this study was to evaluate Fenton process
efficiency in cyanide removal from aqueous solution.
Materials and Methods: This
is an experimental study Conducted at Lab scale in a batch system. We
investigated effect of different variables including pH, mole ratio of Fe
2+/
H
2O
2, contact time, and initial concentration of cyanide.
Data were analyzed using Excel software.
Results: We found that
cyanide with initial concentrations of 0.4 mM/L was reduced by 92 %. This
removal result was related to oxidizing agent of hydroxyl radicals under
optimum conditions including pH = 4, molar ratio Fe
2+/ H
2O
2=
0.046 (Fe
2+=0.27 mM/L) after 6o min reaction time. An increase in
reaction time was not improved cyanide removal efficiency. Moreover, the Fenton
process efficiency in cyanide removal decreased from 92 to 60 %, by increasing
the initial cyanide concentration from 0.4 to 0.6 mM/L.
Conclusion: It can be
concluded that Fenton oxidation Process can be considered as a suitable
alternative for cyanide removal to achieve environmental standards.
Sohrab Delangizan, Zainab Jafari Motlagh,
Volume 6, Issue 1 (5-2013)
Abstract
Background
and Objectives:
Dust phenomenon has adverse effects on the health of the population.Due to the
increasing concentration of Kermanshah dust phenomenon in recent years, The aim
of this study was to measure the concentration of the sensitivity coefficients
between dust phenomenon hospitalization and mortality rates for heart and
respiratory.
Materials
and Methods:
This was a descriptive study in which we studied the sensitivity coefficient of
hospitalization and mortality rates for heart disease and respiratory to
changes of dust concentration.. The study duration was during March-September
2010 and 2011. We collected the dust
phenomenon data from Kermanshah Province Environmental Protection Department.
The admissions and mortality of the cardiovascular and respiratory sufferers
was collected from the Imam Ali, Imam
Reza, and Imam Khomeini governmental hosiptals in Kermanshah.
Results: 1% increase in air pollution
caused by the dust phenomenon will result in increasing about 0.5 % of the respiratory patients, 1% cardiac patients,
and about 0.3% of the heart disease mortality. The relationship between dust
phenomenon and respiratory sufferers was statistically not significant.
Conclusions: We found that respiratory and
cardiovascular hospital admission has a high sensitivity to dust phenomenon.
This sensitivity has increased from 2010 to 2011. This sensitivity was greater
for males than females. At least, during
March-September 2010, for every 100% increase in the concentration of dust
phenomenon, cardiovascular mortality increased by 29%.
!mso]>
ject classid="clsid:38481807-CA0E-42D2-BF39-B33AF135CC4D" id=ieooui>
َahmad Joneidi Jafari, Ayooob Rastegar, Mahdi Farzadkia, Roshanak Rezaee Kalantary, Zahra Rezaee Gozalabad,
Volume 6, Issue 4 (3-2014)
Abstract
Background and Objective:Application of compost containing heavy metals can increase the concentration of metals in soil and groundwater. Therefore,the aim of this study was to investigate leaching lead, chromium,and cadmium from three soils (a sandy loam, a sandy clay loam and silt clay loam) amended with compost from the municipal solid waste. Material andMethod:First, the selected soils were repacked into columns (with an inner diameter of 100mm and a height of 600mm). Treatments included(a) low metal content compost (LMCC), (b) enriched metal content compost (EMCC) and (c) control. Then soil columns were incubated at room temperature for 9 days and were irrigated daily with deionized water to make a total of a 250 mm. Leachates were collected and analyzed for pH, EC, Pb, Cr, and Cd concentration. Results: It was found that the application ofEMCCwas significant (p≤0/05) on reducing pH, increasing electrical conductivity and leakage of metalscompared withcontrolin all three soils. But application of LMCC was not significant (p≥0/05) on the metals leaching compared withcontrolin all three soils. The overall quantities of metals leached followed the sandy loam> sandy clay loam> silt clay loam. Conclusion: The concentration of metals in the leachates depended on the soil characteristics and on the type of compost added to the soil. Therefore,application of enriched metal content compost on the soils containinga high percentage ofsandmay pose a risk in terms of groundwater contamination with heavy metals.
Majid Kermani, Mitra Gholami, Zahra Rahmani, Ahmad Jonidi Jafari, Niaz Mohammad-Mahmoodi,
Volume 6, Issue 4 (3-2014)
Abstract
Background & Objectives: Cationic dyes such as basic violet have many applications in different industries. The degradation of basic violet by means of UV, UV/H2O2, US, and US/H2O2 processes was investigated. Materials and Methods: Photolysis process was accomplished in a laboratory-scale batch photoreactor equipped with a 55 W immersed-type low-pressure mercury vapor lamp (UVC) and sonolysis process was investigated in a sonoreactor with high frequency (130 KHZ) Plate Type transducer at 100 W of acoustic power with emphasis on the effect of various parameters and addition of Na2SO4 on discoloration and degradation efficiency. Results: Complete decolonization of cationic BV 16 was achieved in 8 minutes using UV/H2O2 process. In addition, it was found that sonochemical decolorization is a less efficient process, comparing with photochemical process, as the decolorization proceeds to only 65% within 120 min. Low concentration of dye and natural pH resulting from dissolution of salt favors the degradation rate of dye. The results showed that sodium sulfate enhances the rate of sonochemical degradation of dye. In addition, kinetic parameters were obtained by application of first order equations. Conclusion: The results showed that UV/H2O2 and US/H2O2 processes can be effective in the removal of BV16 from aqueous solutions. Considering dye removal efficiency and availability, photochemical process combined with hydrogen peroxide can be recommended as a fast effective method for removal of dyes from aqueous solutions.
B Kakavandi, R Rezaei Kalantary, A Jonidi Jafari, A Esrafily, A Gholizadeh, A Azari,
Volume 7, Issue 1 (7-2014)
Abstract
Background and Objective: Extreme use of antibiotics and discharging them to the environment lead to serious consequences. Activated carbon is the most commonly adsorbent for these contaminants but its main drawback is difficulty of its separation. The objective of this study was synthesis of magnetic activated carbon by Fe3O4 and investigating its efficiency in adsorption of amoxicillin from synthetic wastewater. Materials and Methods: Materials and Methods: Physical and structural characteristics of the adsorbent synthesized were analyzed using SEM, TEM, XRD and BET techniques. The effect of factors like pH, initial concentration of amoxicillin and adsorbent, contact time, and temperature were investigated to determine thermodynamic parameters, equilibrium isotherms, and kinetics of adsorption process. Results: Physical characteristics of the magnetized activated carbon showed that Fe3O4 nanoparticles had the average size of 30-80 nm and BET surface area was 571 m2/g. The optimum conditions of adsorption were: pH=5, contact time=90min, adsorbent dose of 1g/L and temperature 200C. The equilibrium isotherms data showed that the adsorption process fitted both Freundlich and Longmuir models with the maximum capacity of 136.98 mg/g. The kinetic of the adsorption process followed pseudo second-order model. The negative values of &DeltaH0 and &DeltaG0 obtained from studying the adsorption thermodynamic suggested that amoxicillin adsorption on magnetic activated carbon was exothermic and spontaneous. Conclusion: The present study showed that the magnetic activated carbon has high potential for adsorption of amoxicillin, in addition to features like simple and rapid separation. Therefore, it can be used for adsorption and separation of such pollutants from aqueous solutions.
Shaho Karami, Gholamreza Nabibidhendi, Hamidreza Jafari, Hassan Hoveidi, Amir Hedayati,
Volume 7, Issue 2 (10-2014)
Abstract
Background & Objectives: Human environment is surrounded bychemicals that could directly or indirectly endanger human health. Some statistics of WHO is indicative of the fact that four million people are employed in the chemical industry throughout the world and one million people die or become disabled annually due to contact with chemicals. Moreover, 1-4 Millions chemical toxicity occur annually. The purpose of this study was to understand the risks involved in chemicals in the workplace, to assess the task risk, and to propose appropriate control measures in order to eliminate or reduce risk in the petrochemical industry. Materials & Methods: In this study, the chemicals were identified in Arak Petrochemical and features that are indicative of hazardous materials were identified and using TOPSIS, The hazard rate were determined. Then the job duties of employees and employee exposure rate with chemicals were calculated and finally, a risk rate for exposure to chemicals in job duties was determined. Results: It was found that chemicals do not have too high risk to employees however, but the high risky chemicals were five chemicals including naphtha, ammonia, acetic acid, chlorine, and methanol for operational staff and two chemicals, i.e. ammonia and chlorine for operation and maintenance staffs . Conclusion: It is better to have an alternative for the materials that their risk rang is high and very high, and their production is suggested to be avoided.
R Nabizadeh, K Naddafi, A Jonidi Jafari, M Yunesian, A Koolivand,
Volume 7, Issue 3 (5-2014)
Abstract
Background & Objectives: Remaining crude oil in storage tanks lead to accumulation of oily sludge at the bottom of the tank, which should be treated and disposed of in a suitable manner. The aim of the present study was to investigate the efficiency of chemical oxidation using H2O2 and Fenton’s reagent in removal of Total Petroleum Hydrocarbons (TPH) from bottom sludge of crude oil storage tanks. Materials & methods: In this experimental study, hydrogen peroxide and Fenton’s reagent were added to the sludge in six concentrations including 2, 5, 10, 15, 20, and 30% (w w-1) and TPH was measured for a period of 24 and 48 h of reaction time. The oxidants were added in a single and stepwise addition way, both to the pristine and saturated sludge. The elemental analysis of sludge and TPH measurement were carried out using ICP and TNRCC methods respectively. Results: The mean TPH removal of 2, 5, 10, 15, 20, and 30% oxidant concentrations were 1.55, 9.03, 23.85, 33.97, 41.23, and 53.03%, respectively. The highest removal efficiency was achieved in stepwise addition to the saturated sludge. Increasing oxidation time from 24 to 48 h had a little effect on increase in TPH removal. Moreover, the removal efficiency of H2O2 and Fenton was nearly similar. Conclusions: Mere application of chemical oxidation is not capable of complete treatment of the sludge but it is an effective process as a pre-treatment step for decreasing toxicity and increasing its biodegradability.
T Rajaee, R Rahimi Benmaran, H Jafari,
Volume 7, Issue 4 (1-2015)
Abstract
Background & Objectives: The prediction and quality control of the Karaj River water, as one of the important needed water supply sources of Tehran, possesses great importance. In this study, performance of artificial neural network (ANN), combined wavelet-neural network (WANN), and multi linear regression (MLR) models were evaluated to predict next month nitrate and dissolved oxygen of “Pole Khab” station located in Karaj River. Materials and Methods: A statistical period of 11 years was used for the input of the models. In combined WANN model, the real monthly-observed time series of river discharge (Q) and the quality parameters (nitrate and dissolved oxygen) were analyzed using wavelet analyzer. Then, their completely effective time series were used as ANN input. In addition, the ability of all three models were investigated in order to predict the peak points of time-series that have great importance. The capability of the models was evaluated by coefficient of efficiency (E) and the root mean square error (RMSE). Results: The research findings indicated that the accuracy and the ability of hybrid model of wavelet neural network with the attitude of elimniations of time series noise had beeb better than the other two modes so that hybrid model of Wavelet artificial neural network wase able the improve the rate of RMSE for Nitrate ions in comparison with neural network and multiple linear regression models respectively, amounting to 35.6% and 75.92%, for Dissolved Oxygen ion as much as 40.57% and 60.13%. Conclusion: owing of the high capability wavelet neural network and the elimination of the time series noises in the prediction of quality parameters of river’s water, this model can be convenient and fast way to be proposed for management of water quality resources and assursnce from water quality monitoring results and reduction its costs.
M Malakootian, A. H Mahvi, H Jafari Mansoorian, M Alizadeh, A.r Hosseini,
Volume 8, Issue 2 (8-2015)
Abstract
Background and Objective: Phenol and phenol derivatives in industrial wastewater are among the pollutants with priorities. The high cost and low efficiency of some routine treatment processes of industrial wastewater has limited their use. One of the new methods under consideration is, nowadays, adsorption using carbon nanotubes. This study was conducted in order to evaluate the application of alumina-coated multiwall carbon nanotubes in eliminating phenol from synthetic wastewater. Materials and Methods: This study was performed in laboratory at batch scale. Multi-wall carbon nanotubes were coated with Alumina. The concentration of phenol was determined by spectrophotometer through photometry. The effect of pH changes, dosage of adsorbent, contact time, the initial concentration of phenol, temperature, and the concentrations of different salts on the efficiency of absorption was evaluated. Then, the absorption results were described using the Langmuir and Freundlich isotherms and the synthetics of absorption. Results: It was found that absorption efficiency increased significantly by decreasing the initial concentration of phenol and pH and by increasing the carbon nanotube dosage, temperature, and contact time. On the other hand, the maximum elimination of phenol from the solution (98.86%) occurred at 4 mg/l phenol concentration, under acidic conditions (pH=3), at adsorbent dosage of 0.05 g/l, at temperature of 45°C, and contact time of 10 min. Evaluation of the regressions isotherms showed that the process follows the Langmuir model and second-degree synthetic absorption. Conclusion: The high efficacy (98%) of the adsorption process in this study showed that alumina-coated multiwall carbon nanotubes have a good capability in eliminating phenol and can be used as an appropriate and new method for eliminating phenol and its derivatives from wastewater.
M Halimi, Z Zarei Cheghabalehi, M Jafari Modrek,
Volume 9, Issue 3 (12-2016)
Abstract
Background and Objective: Malaria is a disease affecting 300–500 million people in tropical and subtropical regions and causes approximately 2.7 million deaths annually. Currently, no vaccine protects against malaria and resistance to anti-malaria drugs such as chloroquine is increasing and spreading geographically. Moreover, anti-malarial drugs are expensive and often unaffordable to low-income populations. A better understanding of the relationship between the El Niño Southern Oscillation (ENSO), the climatic anomalies it engenders, and malaria epidemic could help mitigate the world-wide increase in incidence of this mosquito transmitted disease. There is evidence of a relationship between climate variability and the transmission of mosquito-transmitted diseases. Therefore, in this study we intended to analyze the relationship between ENSO events and annual malaria occurrence (AMO) in Iran to assess the possibility of using ENSO forecasts for improving malaria control.
Martials and Methods: Two types of data were used: The data of annual malaria incidence in Iran were collected from the national and international reports of malaria occurrence in Iran; the annual malaria occurrence data for 38 years (1974-2013) were collected from related sources. ENSO is a cyclic phenomenon, which its frequency is 2 to 7 years (i.e., irregular) and is the second strongest natural driver of climate variability, the first being normal seasonal variability. This oscillation has two different phases: a warm episode known as El Niño; and a cold episode called La Niña, where warm and cold refer to the direction of departure from average of the equatorial Pacific Sea surface temperature (SST), a fundamental indicator of the ENSO state. The Pearson correlation analysis at 0.95 confident level (P-value=0.05) on monthly timescale was used in order to understand the relationship between ENSO and annual malaria occurrence in Iran. The 2-tailed independent parametric T-test was used knowing that whether there is a significant difference between the La Nina years occurrence and El Nino years occurrence.
Results: The results indicated that a slight negative association could be detected between ENSO and annual Malaria occurrence in Iran. Our finding showed that the detected correlation between monthly ENSO and annual malaria occurrence is statistically significant only in months October and May while no significant relationship between ENSO and AMO at 0.95 confident level was found for other months.. The inverse relationship between ENSO and AMO means that the years having higher malaria occurrence coincides with the warm ENSO phases or EL Nino episode while the years having lower malaria occurrence coincides with the cool ENSO phases or La Nina episode. In El Niño episode, the annual occurrence of malaria is about 0.2 to 0.3 higher than La Niña episode years.
Conclusion: The positive association between El Niño and rainfall of Iran resulted in higher occurrence of malaria by proliferation of Anopheles mosquito especially in southern and southeastern region of Iran.
A Koolivand, K Naddafi, R Nabizadeh, A Jonidi Jafari, M Yunesian, K Yaghmaiean, S Naseri,
Volume 9, Issue 3 (12-2016)
Abstract
Background and Objective: The performance of in-vessel composting process, as one of the most effective methods of oily sludge treatment, depends on factors such as nutrients and temperature. Therefore, it is crucial to investigate the trend of changes of these factors. The aim of the present study was to investigate the trend of changes of organic carbon, nitrogen, phosphorus, and temperature during the composting of bottom sludge of crude oil storage tanks.
Materials and Methods: The sludge was mixed with the immature compost at the various ratios of sludge to compost including 1:2, 1:4, 1:6, 1:8, and 1:10 with the initial C/N/P of 100/5/1 and then was composted for a period of 10 weeks. The process of mixing and moisture adjustment of the mixtures was done 3 times a day during the composting period. Sampling and analysis were performed every week for organic carbon, nitrogen, and phosphorus and every day for temperature.
Results: The research indicated that the concentrations of organic carbon, nitrogen, and phosphorus were decreased sharply during the first weeks of the process and then they were decreased gently. At the final stage of the composting, the ratios of C/N and C/P increased from 20:1 and 100:1 to 26:1 and 166:1, respectively. In addition, the temperature of the reactors was kept in the mesophilic range during the process period.
Conclusion: The similar trend of decrease of organic carbon, nitrogen, and phosphorus in the composting reactors is an indication of decreasing the activity of the microorganisms involved in petroleum hydrocarbons degradation.
