Showing 45 results for Process
M Aghanejad, A.r Mesdaginia, F Vaezi,
Volume 2, Issue 1 (7-2009)
Abstract
Backgrounds and Objectives: Now a days modified activated sludge ways are used for standard removing nutrient substances from waste water that is named Enhanced biological phosphorus removal One of the most suitable ways is Anoxic-Oxic(A/O) process. The goal of this research is investigation and solving existing problems of Khoy power plant(P.P) waste water treatment plant(WWTP)and optimizing of phosphorus removal in it.
Materials and Methods: This research is done full scale in this treatment plant. The treatment plant was operating with extended aeration process, and some problems had, so in the first stage with in investigation of total efficiency, problems and their reasons determined. In the second stage after operational modifications existing problems was solved and real efficiency of treatment plant particularly for phosphorus(P) removal determined. In the third stage changes, system converted to A/O process and new system was tested with Changing parameters like food/microorganism(F/M), return sludge ratio(RAS)and sludge retention time(SRT)
Risults: In the first stage the most important problems were over concentration of BOD,TSS, and P in effluent of treatment plant and overgrows of alga observed in parts of treatment plant and effluent receiving conduit. The main reason of high concentration of P was considered releasing of sludge. In the second stage operating condition modification efficiency of P removal increased from 50to 62 percent. In the end of third stage value of P removal reached to %82 and the most suitable of anoxic contact time was determined 3to4 hours, SRT terry day and F/M ratio o.12,that the most effective change has been the decrease of SRT to three days.
Conclusion: Adjusting of operating factors like SRT,RAS, sludge processing way in WWTP can increase P removal in them with in total efficiency remaining, such as in this case it was %12. In waste water treatment particularly for P removal the A/O process is suitable so in this project its effect on P removal efficiency has been %20.
M Panahandeh, M Arastou, A Ghavidel, F Ghanbari,
Volume 2, Issue 4 (3-2010)
Abstract
Backgrounds and Objectives: Landfill site selection is an important action in integrated solid waste management process. Difference criteria should be paid attention in site selection, so using of special methods are necessary to assimilate the criteria. In this research, GIS software and Analytical Hierarchy Process were used.
Materials and Methods: First of all, maps were built in considering to economical, social and environmental factors, in next step, each layer, was graded. Low grade showed non coordination or less coordination and high grade showed more coordination.
Results: Assimilate of graded map in AHP process, separates area into unsuitable, suitable and very
suitable parts.
Conclusion: Very suitable parts can have high priority in decision making and also suitable parts can have high priority for development projects in future.
M.t Samadi, M.h Saghi, K. Ghadiri, M. Hadi, M. Beikmohammadi,
Volume 3, Issue 1 (4-2010)
Abstract
Backgrounds and Objectives:Phosphate discharges from domestic and industrial waste water to water bodies. High concentrations of phosphate in water stimulate the eutrophication phenomenon that causes taste and odor in water, losing dissolved oxygen and aquatic life in rivers or surface waters. Aim of this study is survey of phosphate adsorption on simple nano zeolite Y and nano zeolite Y that was modified with a cationic surfactant (HDTMA-Br).
Materials and Methods:In This study we used simple nano zeolite Y and nano zeolite Y in form of Surfactant Modified Zeolites (SMZs) using batch tests to adsorption of Phosphate fromAqueous Solutions. The adsorbants were contacted with different initial phosphor concentrations (5, 10 and 15 mg/l), pH (4, 7, 12), contact time (30, 60, 90, 120, 150 and 180 minutes) and weight of adsorbant (0.2, 0.4, 0.6, 0.8 and 1g). the extracted solution was determined for Phosphate concentration by the ammonium molybdate and tin chloride method with spectrophotometric detection at 680 nm. Results:Results of this study show that, with increase in contact time, decrease in pH, increase in zeolites concentration and decrease in initial phosphate concentration, the removal efficiency increased. And the Both isotherm of Langmuir and Freundlich models (r2 > 0.997 and r2 > 0.996 respectively) were agreement with adsorption equilibrium of phosphate. Reduced Chi-Sqr For Langmuir and Freundlich models were (0.00079) and (0.0011) respectively. Pseudo first-order kinetic models fits well with experimental data (r2>0.963).
Conclusion: From this survey, it is concluded that performance of modified nano zeolite Y for adsorption of phosphate in same conditions is better than non-modified zeolite Y. In general the modified nano zeolite Y presented a good profile for removal of phosphate. Therefore SMZs is a suitable candidate for removal of Phosphate molecules from contaminated solutions in contaminated waters.
A Maleki,
Volume 3, Issue 2 (7-2010)
Abstract
Backgrounds and Objectives: Carcinogenic and mutagenic potential of some azo dyes as a category of common dyes in different types of industries has been reported. The degradation of one commercially available dyestuff [C.I. Reactive Red 198 (RR 198)] by means of ultraviolet radiation (UV), ultrasonic irradiation (US), UV/H2O2 and US/H2O2 processes was investigated.
Materials and Methods: Photolysis process was accomplished in a laboratory-scale batch photoreactor equipped with an 55W immersed-type low-pressure mercury vapour lamp (UVC) and sonication in a sonoreactor with low frequency (42 kHz) plate type transducer at 170W of acoustic power with emphasis on the effect of various parameters on decolouration and degradation efficiency.
Results: Initial results showed that, color removal efficiencies by US and US/H2O2 processes were negligible. Almost complete disappearance of RR 198 (20 mg/L) in UV/H2O2 process was possible to achieve after 10 min of irradiation. It is found that lower pH and lower concentration of dye favor the dye degradation. Hence any increase in initial dye concentration results in decreased decolouration rates. Also, the experimental results indicated that the kinetics of sono-oxidation and photo-oxidation processes fit well by pseudo-first order kinetics and first order reaction kinetics, respectively.
Conclusion: It is concluded that UV/H2O2 reaction was more effective than other reactions in bleaching and the reaction rate was sensitive to the operational parameters and increased with increasing H2O2 concentration up to 15 mM.
M Malakootian, N Jafarzadeh Haghighi Fard, M Ahmadian, M Loloei,
Volume 3, Issue 2 (7-2010)
Abstract
Backgrounds and Objectives: Untreated leachate is discharging into the environment in the many countries of worldwide. Leachate treatment methods have not been unified so far due to variable composition of leachate. Moreover, the uncontrolled management of leachate, cause many environmental dissociates. The aims of this study apply the Fenton process to decrease the pollutants of Kerman leachate.
Materials and Methods: Rawleachatewas obtained fromcompactor vehicles used for the collection of Kerman city solid waste, before final disposal. In order to removal of biodegradable organic compounds, a rector was built based on characteristics of landfill Kerman city and raw leachate underwent anaerobic treatment in this pilot. In the next stage, treated leachate in the pilot, was affected by Fenton process. The optimized parameters in Fenton process including pH, reaction time and dosage of H2O2 and Fe2+ were also studied.
Results: The results showed that TSS, BOD5 and COD decrease to 62*, 96*and 89*, respectively, after 60 days treatment in the pilot. BOD5/COD ratio also decreased from 0.6 to 0.2 in anaerobic treated leachate. In optimum condition (pH=3, reaction time=75 min, Fe2+=1400 mg/L and H2O2 = 2500 mg/L) maximum COD removal was 78 * by Fenton process. BOD5/COD ratio increased from 0.2 to 0.51 which showed an increase in biodegradability of leachate as a result of Fenton process.
Conclusion: anaerobic biologically treatment followed by Fenton processes could be assumed as an efficient process that could improved the leachate quality. Biological treatment to reduce leachate pollution alone was not enough. The most important Fenton process advantage is reduction of refractory and toxic leachate compounds and increasing leachate.s biodegradability.
M.h Dehghani, S Nasseri, M Ghaderpoori, A.h Mahvi, R Nabizadeh Nodehi,
Volume 3, Issue 4 (1-2011)
Abstract
Backgrounds and Objective: Surfactants are one of the largest pollutants which exist in urban and industrial wastewaters. Large quantities of surfactants have entered to the environment since last decade due to increased use of synthetic detergent in industrial and home consumptions.In this study, the efficiency of UV/H2O2 process in removal of linear alkylbenzane sulfonate (LAS) from aqueous solutions was investigated.
Materials and Methods: In this study methylene blue active substane(MBAS)method and spectrometery were used to determine anion and residual surfactant respectively. In this study important variables were H2O2 concentration, initial concentration of surfactant, pH and duration of UV radiation. The effect of UV/H2O2 process on the degradation of LAS was analyzed statistically by using Multiple Linear Regression test.
Results: The resulted showed that after 20 minute, ultraviolet radiation solely removed 38.44 percent of Anionic detergent, Hydrogen peroxide showed no significant removal of detergent solution in the time course study. The efficiency of UV/H2O2 process in 10, 20 and 30 minute were to 86.2, 90 and 96.5 %, respectively.
Conclusion: The results showed that the efficiency of ultraviolet radiation and hydrogen peroxide process in anionic detergent was not significant thoogh it was considerable in combination process (UV/H2O2).
S Hemmati Borji, S Nasseri, R Nabizadeh Nodehi, A.h Mahvi, A.h Javadi,
Volume 3, Issue 4 (1-2011)
Abstract
Backgrounds and Objectives: Phenol and phenolic compounds are widely used in industry and daily liFe, and are of high interest due to stability in the environment, dissolution ability in water and health problems. In this regard, phenol removal from water is of high importance. The purpose of this study was to investigate the efficiency of photodegradation process for removal of phenol from aqueous system by use of Fe-doped TiO2 nanoparticles prepared by sol-gel method.
Materials and Methods: Phenol concentrations of 5, 10, 50 and 100 mg/L were prepared and exposed to UV and Fe-doped TiO2, separately and simultaneously. Also the effect of initial phenol concentration, Fe-doped TiO2 loading and pH were studied. Various doses of photocatalist investigated for Fe- doped TiO2 were 0.25, 0.5 and 1 g/L. pH was studied at three ranges, acidic (pH=3), neutral (pH=7) and alkaline (pH=11).
Results: Maximum degradation was obtained at acidic pH, 0.5 g/L of Fe-doped TiO2 for all of phenol concentrations. With increasing initial concentration of phenol, photocatalytic degradation decreased. In comparison with Fe-doped TiO2/UV process, efficiency of UV radiation alone was low in phenol degradation (% 64.5 at 100 mg/l of phenol concentration). Also the amount of phenol adsorbed on the Fe-doped TiO2 was negligible at dark conditions.
Conclusion: Results of this study showed that Fe(III)- doped TiO2 nanoparticles had an important effect on photocatalytic degradation of high initial phenol concentration when Fe(III)-doped TiO2/ UV process applied.
M Khodadadi, M.t Samadi, A.r Rahmani,
Volume 4, Issue 3 (10-2011)
Abstract
Background and Objectives: Water pollution by pesticides has adverse effects on the environment and human health, as well .In recent years, advanced oxidation processes, have been gone through to a very high degree for pesticides removal. Poly-Aluminum chloride (PAC) used for water treatment, can be effective on pesticides removal. The aim of this research was to study the use of UV/O3 and PAC in the removal of pesticides from drinking water.
Materials and Methods: In this descriptive- analytical survey, specific concentrations of pesticides (1,5,10,15,20 ppm)namely Diazinon, Chlorpyrifos, Carbaril were prepared through addition to deionized water. Dichloromethane was used for samples&apos extraction, samples extracted with Liquid- Liquid & Solid-phase extraction , finally entered bath reactor at pH (6,7,9) .The samples then exposed to UV/O3at contact time of (0.5,1,1.5 and 2 hours) . In the PAC pilot , the effects of various concentrations of pesticides, and PAC - ranging (12/24 and 36 ppm) were investigated for the efficacy of pesticides removal. All samples analyzed by GC/MS/MS and HPLC.
Results: It was found that in UV/O3 reactor, with the rise of pH, decrease in pesticides concentration, and rise of contact time, the efficiency of removal increased too. In the PAC pilot, increase in PAC concentration and decrease in pesticides concentration , both increased the efficiency. Besides, both of the methods showed high efficiencies in the removal of both pesticides,i-e. halogenated Organophosphorus (Chlorpyrifos) , non- halogenated Organophosphorus (Diazinon) at the degree of over (%80 ) In case of carbamate pesticides (e.g. Carbaril) efficiency was over (>%90). One-Way Anova & Two -Way Anova were used to analyze the obtained data.
Conclusion: According these results these two methods are suggested for the removal of pesticides from aqueous solutions.
M Moeinaddini, M.h Tahari Mehrjardi, N Khorasani, A Danekar, A.a Darvishsefat, F Shakeri,
Volume 4, Issue 4 (3-2012)
Abstract
Background and Objectives: Solid waste municipal landfill can have injurious effect on society health, economic and environment. Therefore, spread evaluation in locating landfill is necessary to identifying the best places. The purpose of this paper is locating landfill for solid waste municipal for center of Alborz province.
Materials and Method: In this paper, suitable areas are identified for land filling solid waste municipal by weighted linear combination and cluster analysis in 20 years period. Thus, suitable areas were weighted by FAHP method. Those weights were used for ranking areas by DEA technique.
Result: Results showed among five landfill alternatives for solid waste municipal for center of Alborz province, alternative 1 is the best for land filling. This place is just 7 percent of total suitable places.
Conclusion: The approach are used in this article (combination method of fuzzy analytic hierarchy process & Data envelopment analysis) can be suitable for locating in other areas because when an option add or delete option ranking is not different with previous
A Khodadadi, H Ganjidoust, H Ijad Panah,
Volume 4, Issue 4 (3-2012)
Abstract
Background and Objectives: Many industrial effluent plants contain amounts of hard biodegradable compounds such as β-naphthol which can be removed by conventional treatment systems. The objective of this research is to treat wastewater containing naphthalene by nano titanium oxide coated on activated carbon.
Materials and Methods: Photocatalytic experiments were carried out for different concentrations of β-naphthol using time and pH as dependent factors. Nano TiO2 coated on activated carbone in one liter batch reactor and the resultants compounds' concentration were measured in a photocatalytic reactor with UV-C of 12 Watt.
Results: The experimental results indicated that UV/ nano TiO2 coated on activated carbone removed 92% of β-naphthol with concentrations of 100 mg/L within an overall elapsed time of three hours. β-naphthol total removal with concenteration of 25 mg/L was observed in two hours.
Conclusions: UV/ nano TiO2 process is very fast and effective method for removal of β-naphthol and pH 11 was indicated as the optimum pH.
Emad Dehghani Fard, Ahmad Jonidi Jafari, Roshanak Rezae Kalantari, Mitra Gholami, Ali Esrafili,
Volume 5, Issue 2 (10-2012)
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.
Amir Bagheri, Gholamreza Moussavi, Ali Khavanin,
Volume 5, Issue 2 (10-2012)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Formaldehyde is a toxic substance and harmful to human
beings and the environmental health. Therefore, the effluents containing
formaldehyde have to be efficiently treated before discharging into the
environment. This study was aimed at investigating the efficiency of
Electro-Fenton (EF) Process in pre-treating industrial wastewater containing
high concentrations of formaldehyde.
Materials and Methods: The effect of the important operational variables including pH, current
density, H
2O
2 dosage, and reaction time were evaluated on the degradation of
7500 mg/L formaldehyde using batch tests. The EFP batch reactor was consisted
of a cylindrical glass column with 5.20 cm in internal diameter and 34.50 cm in
height. Working volume of the reactor was 500 mL.
Results: The maximum
formaldehyde removal was obtained at alkaline pH of 10, H
2O
2 concentration of
10 mM/min, current intensity 8.5 mA/cm2, and the reaction time of 6 minute.
Furthermore, aerating the EFP cell could enhance the formaldehyde removal.
Complete removal of formaldehyde was obtained under the abovementioned
operational conditions.
Conclusion: This study
demonstrated that the EFP is capable of reducing high concentration of
formaldehyde (7500 mg/l) to the level suitable for biological post-treatment.
Mohammad Reza Mehrasbi, Sorur Safa, Amir Hossein Mahvi, Ali Assadi, Hamed Mohammadi,
Volume 5, Issue 3 (10-2012)
Abstract
Backgrounds and Objectives: The base structure of total petroleum hydrocarbons (TPH)
is made of hydrogen and carbon. Widespread use, improper disposal and
accidental spills of this compounds lead to long term remaining of
contaminations such as organic solvents and poly aromatic hydrocarbons (PAHs)
in the soil and groundwater resources, resulting in critical environmental
issues. In this study, an oil-contaminated soil was washed using Tween 80
surfactant and the application of photo-Fenton process (UV/Fe2+/H2O2)
for treatment of the produced wastewater was evaluated.
Materials and Methods: Tween 80 is a yellow liquid with high viscosity and soluble in water. In order
to determine of the photo-Fenton process efficiency, we studied effective
variables including Fe concentration, pH, H2O2 concentration, and irradiation time. The UV irradiation source was a
medium-pressure mercury vapor lamp (400 w) vertically immersed in the solution
within 2L volume glass cylindrical reactor.
Results: The results
showed that efficiency of COD removal depends on the initial Fe concentration, pH,
H2O2 concentration and irradiation time.
Under optimum conditions, (Fe: 0.1mM, H2O2:
0.43 mM, pH: 3 and UV light irradiation time: 2 hours) the removal efficiency
of COD was 67.3%. pH plays a crucial role in the photo-Fenton process such that
the removal efficiency increased with decreasing of pH.
Conclusion: According
to the results of this study, under acidic condition, this process is an
efficient method for COD removal from the wastewater studied.
Mohammad Malakootian, Mahdi Asadi, Amir Hossein Mahvi,
Volume 5, Issue 4 (2-2013)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Synthetic dyes represent one of the largest groups of
pollutants in wastewater of dying industries. Discharging these wastewaters
into receiving streams not only affects the aesthetic but also reduces
photosynthetic activity. Electrochemical advanced oxidation processes such as
Electro-Fenton process are low operational and have high mineralization degree
of pollutants. In this study, we investigated affective factors in this process
to determine the optimum conditions for dye and COD removal from aqueous
solutions containing Reactive Blue 19 dye.
Materials and Methods: Synthetic samples containing Reactive Blue 19 dye were prepared by dissolving
dye powder in double distilled water. and the the solution prepared was
transferred into pilot electrochemical cell having two anode and cathode
electrode made of iron and carbon. Electro-Fenton process was began by adding
of Fe
2+ ions and establishing electrical potential difference. After
testing and at specified time intervals, each sample was collected from the
pilot cell, and process performance was evaluated through measuring dye
concentration and COD.
Results: Based on the
results obtained, optimum conditions of Electro-Fenton process for dye and COD
removal was determined. Accordingly, potential difference of 20 volt for dye
concentration up to 100 mg/L and potential difference of 30 volt for dye
concentration of more than 200 mg/L, reaction time 60 minutes, 0.5 mg/L of Fe
2+ concentration and suitable pH for the maximum dye removal efficiency equaled 4
respectively. Under such conditions, the dye and COD removal was 100 and 95%
respectively.
Conclusion: Based on
the results obtained, it was revealed that Electro-Fenton process has
significant ability in not only dye removal but also in COD removal.
Accordingly, it was found that the effective parameters in Electro-Fenton
process for removal Reactive Blue19 dye are electric potential difference,
concentration of iron ions and electrolysis time.
Marzieh Mahtabi Oghani, Akbar Najafi , Habiballah Yunesi,
Volume 6, Issue 3 (12-2013)
Abstract
Background and objectives: Nowadays, landfilling is most common method in many countries owing to lower cost and adaptation to wide range of solid waste. Site selection of landfill requires evaluating several parameters such as municipal government requirements, environmental regulations and a large number of quantitative and qualitative criteria. The aim of current study was to compare AHP and TOPSIS in landfill site selection. For this purpose, two mentioned methods were applied to select suitable site in Karaj. Materials and methods: In present study, 4 candidate sites in south of Karaj were selected for landfill by overlaying data layers (digital maps) and query functions in Arc GIS 9.2. Prioritizations between alternatives were conducted by AHP and TOPSIS technique according to the criteria mentioned. Eventually, we compared and evaluated the AHP results and TOPSIS results with each other. Result: According to AHP, site prioritization was 3,2,4,1 respectively whereas, in the case of TOPSIS, it was ranked 4,3,2,1, respectively. These results showed that both methods are suitable to determine site priority. Conclusion: As in AHP, alternatives are compared with respect to goal and criteria, consequently it has better precision and higher accuracy and confidence compared with TOPSIS.
Behrooz Karimi, Mohamad Sadeg Rajaie, Mohamad Javad Ghanadzadeh, Masome Mashayekhi,
Volume 6, Issue 4 (3-2014)
Abstract
Backgrounds and Objectives: Nowadays, global concerns about nitrate in groundwater and its adverse impact on health have increased. This study aims to evaluate the efficiency of nitrate reduction from aqueous solution through modified Fenton process using Nano scale zero-valent iron. Material and Methods: This research was an experimental study and performed at laboratory scale. Nitrate reduction was conducted by advanced oxidation process of Fe°/FeІІ/FeШ/H2O2 at pH 2-10, contact time 10-90 min, nitrate concentrations of 50-300 mg/L, and the molar ratio of [H2O2]/[Fe] 0.5-5. The effect of adding H2O2, molar ratio of reagents, contact time, and pH on nitrate removal was examined and optimal conditions for each of these parameters were determined. Spectrophotometer Dr/5000 was used to measure nitrate in the effluent. Results: We found that the optimal parameters in our studywere pH 3, the molar ratio [H2O2]/[Fe°] of 0.5, and the contact time 15 min. By applying these conditions, nitrate removal efficiency at the retention time 15 min, initial nitrate concentration of 100 mg/L, iron concentration of 10 mg/L, and pH 4 for FeШ، FeІІ، Fe°، FeІІ/Fe°/H2O2 and FeШ/Fe°/H2O2 was 10.5, 27.6, 36.5, 62.3, and 74% respectively. Conclusion: According to the experimental results, it was determined that modified Fenton process using zero iron nano-particles can reduce nitrate under optimal conditions and this method can be used for the removal of similar compounds.
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.
Seyed Ali Jozi, Maryam Firouzei,
Volume 6, Issue 4 (3-2014)
Abstract
Background and Objectives: Nemone Tehran Poultry Slaughterhouse having an area of 13000 m2 is located at District 3, Region 5 of Tehran Municipality and in Morad Abad Quarter .This study aimed at analysis the environmental impacts of the abovementioned slaughterhouse. For this purpose, we applied analytical hierarchy process (AHP) as one of the multiple criteria decision making methods (MCDM). Materials and Method: First, we determined the criteria and options required through analyzing the project impacts. Then, for final validity of criteria, we used experts questionnaire. Special vector technique through using the Expert Choice software was used in order to set priorities for criteria and options. Results: Analysis of the slaughterhouse effluent indicated that it can neither be discharged into the surface water and well nor suitable for irrigation and agricultural purposes. Noise evaluation showed that rate of noise measured is beyond the standard limits. The laboratory experiment results on air pollutants was lower than the standard level. Conclusion: The results indicated that from the pollution perspective in the slaughterhouse, wastewater weighted 0.497 is the primary preference and sound, air, and odour weighted 0.229, 0.136 and 0.080 are the subsequent preferences. Cultural and socioeconomical environment ranked hgiher relative to the chemical-physical environment and then biological environment. Finally, regarding to the main significant environmental problem of slaughterhouse (Wastewater), optimization of the slaughterhouse wastewater treatment system and constant monitoring of the external sewage quality is in priority.
Gh Asgari, A. R. Rahmani, A. R. Dehghanian, A. R. Soltanian,
Volume 7, Issue 1 (7-2014)
Abstract
Background and Objectives: In this experimental study, we used Analytical Hierarchy Process method to determine the best wastewater treatment process for dairy products factories. That is a multi-criteria decision making techniques and is based on expert knowledge. Materials and Methods: First, we formed the hierarchical structure and defined the main criteria and indicators. Then, we investigated the current situation of the treatment process through field observations and conducting influent-effluent analysis. Later, we converted the results obtained into quantitative indices. Then we weighted the main criteria, and their related sub criteria, depending on existing conditions we performed the experiments required and considered the experts ideas. Finally, Evaluation and prioritization of the options was conducted using Expert choice software. Then the sensitivity analysis was performed for main criteria and we evaluated the influence of the parameters weight change on the options. Results: In comparison with the main criteria, environmental criteria were more important followed by engineering criteria, economic and management criteria. Conclusions: Due to the influence of various parameters in choosing optimal wastewater treatment, Multi-criteria decision-making methods are necessary. Finally, “UASB + Aeration” was found to be the first priority followed by “Anaerobic filter + Aeration”, “Anaerobic lagoon + Aeration (2) + Sedimentation (2)”,” Anaerobic filter + Aeration (2) + Sedimentation (2)”. “Septic tank + Trickling filter + Aeration” system was found to be less preferable than other options.
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.
