Showing 28 results for فرایند
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.
R Shokuhi, A.h Mahvi, Z Bonyadi,
Volume 3, Issue 2 (7-2010)
Abstract
Backgrounds and Objectives: Cyanide is a species of high toxicity that found mostly in industrial effluents such as electroplating, metal mining, metallurgy and metal cleaning processes. Intrance of it to Existence enviroment contains very health hazardous. Purpose of this study, efficiency compare of both sonochemical and photosonochemical technologies for cyanide removal from aqueous solutions.
Materials and Methods: in this study, it has been used from a productive set of 500w power ultresound waves in of two frequencies 35 kHz and 130 kHz and a 125 W low pressure mercury lamp. Experiments were performed at initial cyanide concentrations varying from 2.5 to 75 mg/L. in this study, The effects of parameters such as pH, time and initial cyanide concentration on the sonochemical and photosonic degradation have been studied.
Results:The results of the study showed that the maximom removal efficiency of cyanide had been achieved sonochemical technology was 71% while it was 74% by photosonic at frequency of 130 kHz, at time of 90 min, pH of 11 and initial cyanide concentration of 2.5 mg/l.
Conclusion: The results of the study showed that efficiency of photosonic process is more than for sonochemical cyanide removal fromaqueous solutions.Also efficiency of cyanide removal has direct relationship with pH, frequeny and time ,and it has reverse relationship with cyanide concentration for both processes.
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.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).
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.
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.
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.
Reza Shokoohi, Salah Azizi, Said Amir Ghiasian, Javad Fredmal,
Volume 7, Issue 2 (10-2014)
Abstract
Background and Objectives: Pentachlorophenol (PCP) is an organic compound and phenolic derivatives categorized as priority pollutants that have harmful effects on humans, animals, and plants in low concentrations. Therefore, PCP removal from water and wastewater is very important. The aim of this study was to assess the efficiency of A. niger fungus biomass in PCP absorption. Materials and Methods: This was an experimental study in which different steps of the experiments were performed. A. niger strain was prepared from Persian Type Culture Collection of Iranian Research Organization for Science and Technology (IROST). After activation in potato dextrose agar (PDA) culture plates, fungi were incubated for 7 to 10 days at 25 °C. The prepared A. niger biomass was modified by NaOH and then it was used for PCP absorption assay. The concentration of PCP was measured using high-performance liquid chromatography. Results: The findings of present study showed that contact time is an important and effective factor in the PCP absorption rate. Two hours was selected as the optimum retention time in this experiment and after that the removal percentage did not raise significantly. The results of PCP absorption in different pH demonstrated that the adsorption efficiency decreases by rising pH and initial PCP concentration. The effects of contact time, pH and initial PCP concentration on the absorption process was significant (P-value <0.001). Conclusion: The results show that absorption efficiency increases by rising retention time under constant conditions. In addition, at low pH the modified A. niger biomass could be a good absorber for PCP.
S. A. Mirzaee, M.m Amin, M Sarafraz, M Heidari, M.m Ahmad Moazzam,
Volume 7, Issue 4 (1-2015)
Abstract
Background & Objectives: Disposal of pharmaceutical compounds to environment as an emerging pollutants cause concerns significantly and it is necessary to use new methods of sewage treatment for removal of these compounds. The aim of this study was to investigate the inhibition effects of metronidazole before and after using UV254/H2O2 process on specific methanogenic activity of.anaerobic biomass. Materials & Methods: Fourteen anaerobic digestion tests were carried out at batch scale before and after using UV254/H2O2 process in 500 ml reactors with 30% anaerobic biomass and 70% substrate. The liquid displacement method was used. Duration of each test was in the range of 10-17 days. Results: Cumulative Biomethane production in concentrations of 1, 5, 10, 25, 50, and 100 mg/l metronidazole was 34.04, 95.12, 100.86, 3.28, 27.88, and 6.97 ml respectively. This production was 800.73, 243.54, and 10.66 ml in concentrations of 25, 50, and 80 mg/l respectively using UV254/H2O2 process as pretreatment at 60 min retention time. Biomethane production in concentrations of 80,120, and 150 mg/l was 377.2, 380.48, and 63.14 ml respectively at 90 min retention time. Conclusion: Different concentrations of metronidazole had an inhibition effect on anaerobic digestions and therefore the efficient pretreatment method is needed to reduce this inhibition effect. The UV254/H2O2 process is an effective method for degradation and conversion of metronidazole to more biodegradable compounds for anaerobic bacteria consumption and, in turn, to increase biogasproduction in anaerobic digestions.
Sar Mousavi, M Parvaneh,
Volume 9, Issue 2 (9-2016)
Abstract
Background and Objectives: Conventional methods of leachate treatment are inefficient due to high pollution loads and characteristics of the leachate. In recent years, an integrated method has been developed considerably. The aim of this research was to evaluate the effect of powdered activated carbon on the treatment of landfill leachate of Kermanshah City by a columnar aerobic sequencing batch reactor.
Materials and Methods: This study was carried out in three reactors having a total volume of 2000 mL and each having an effective volume of 600 mL in the bench scale. To the reactors 2 and 3 that were similar from environmental conditions and operation point of view with reactor 1 (with no carbon powder), 5 and 10 g/L of PAC were added, respectively. The effects of different doses of PAC (0, 5, 10 g/L) and hydraulic detention times (HRT = 48, 96, 144 h) were investigated in order to remove the Chemical Oxygen Demand (COD) and ammonia nitrogen (NH3-N) from the leachate. The efficiency was investigated using two -way ANOVA test in SPSS software (Ver. 16).
Results: The results of two-way ANOVA showed that there was a significant difference (P-value=0.001) between the removal efficiency of COD and NH3–N at different HRTs with different doses of PAC. The highest removal efficiency achieved at HRT=144 h for COD and NH3-N was in Reactor 1 were 50.11 ± 4.42 and 19.85 ± 1.49%; in reactor 2: 55.67 ± 1.6 and 25.7 ± 0.89%; and in reactor 3: 58.02 ± 3.99and 25.48 ± 1.7%, respectively.
Conclusion: It can be concluded that the combination of biological - activated carbon compared with the biological process, can remove COD and NH3–N of strong sewages such as landfill leachate, although achieving standard treatments using this method is not possible.
M Kermani, M Farzadkia, A Esrafili, Y Dadban Shahamat, S Fallah Jokandan,
Volume 10, Issue 2 (9-2017)
Abstract
Background and Objective: Discharge of industrial wastewater containing Catechol has adverse effects on human and environmental health. Purpose of this study was to determine the effects of catechol toxicity before and after advanced oxidation process (ozonation process) by bioassay test with Daphnia Magna.
Materials and Methods: This study is an applied research in which the toxicity of catechol was determined by Daphnia Magna bioassay test during the ozonation process. First, Catechol stock solution was prepared at a concentration of 250 mg/L. Then, 10 samples were prepared that each contained 0 (control), 0.5, 1, 3, 6, 12, 25, 50, 75 and 100% of volume of primary solution. Initial samples were prepared from reactor effluent in the same volume as those of the samples. According to standard method, 10 Daphnia infants were added to each sample. The samples were observed after 24, 48, 72 and 96 hours. Finally, lethal concentration (LC50) and toxicity unit (TU) were calculated using Probit analysis.
Results: According to the results, Daphnia magna was affected by the toxicity of catechol. LC50 (24-hour) for raw effluent was increased from 13.30 mL/100 mL to 30.4 mL/100 mL after 60 minutes Treatment. The toxicity unit was decreased from 7.51 TU to 3.29 TU accordingly, showing reduction of 56% in toxicity. The toxicity of the treated effluent decreased during ozonation process of catechol.
Conclusion: Based on the bioassay test, ozonation process was able to reduce the toxicity of catechol. Therefore, this process can be used as an option to treat wastewater that contains catechol.
R Rafiee, M Moeinaddini, N Khorasani,
Volume 11, Issue 1 (6-2018)
Abstract
Background and Objective: The aim of this study was to assess the sensitivity and uncertainty analysis of a mass balance model to estimate the rate of aerobic processes in a landfill.
Materials and Methods: Monte Carlo simulation is a common method to evaluate uncertainty of the results of a model. Here, we used a Monte Carlo (MC) simulation. The data obtained from the experiments were used as a baseline. Considering a uniform Probability Distribution Function (PDF) within ±15% deviation, samples were taken from the baseline data. Using randomly selected inputs, model was executed for 1000 iterations and outputs were evaluated. Then, the total Sobol index for each input parameter was determined. The uncertainty of each output was presented by standard error and means observed in MC simulation.
Results: The results of this study revealed that while the uncertainty for the rate of composting process was mainly originated from the measured value of CO2 flux, the evaluated value for the rate of anaerobic digestion process was highly influenced by the value measured for CH4 emission flux. All inputs contributed equally to the uncertainty in the evaluated values for the rate of methane oxidation process. Although a variability of 15% was assumed for the model inputs, the mean value for the outputs from Monto Carlo simulations were close to those obtained by using base values that were in most cases within ±10% limit.
Conclusion: The majority of the uncertainty in the outputs came from the variability in the measurement of the flux of CH4 and CO2. The error in these parameters, however, can be minimized by increasing frequency and replicates of gas samples as these parameters are measured directly for each location.
M Hadi, M Solaimany Aminabad, M Amiri, M Arjipour,
Volume 11, Issue 3 (12-2018)
Abstract
Background and Objective: Treatment of hospital wastewaters has an important role in reducing the discharge of organics and pharmaceutical compounds into aquatic environments. Nowadays, advanced oxidation processes were extensively used for the removal of organic compounds from treated effluents. The study aimed to examine organic compounds removal from real treated effluent of a hospital treatment plant using a lab scale UV/H2O2/TiO2 process by optimizing the process.
Materials and Methods: The effluent characteristics including COD, TOC and DOC were measured and recorded. A hybrid advanced oxidation process (UV/H2O2/TiO2) was used for the removal of organic compounds. The experiments were designed using surface response methodology (RSM). The effects of the independent factors including pH, duration of UV irradiation, H2O2 and TiO2 concentrations on COD, TOC, DOC and the approximate cost of treatment were assessed by analysis of variance (ANOVA).
Results: The optimal condition was 7.2 for pH, 50 mg/L for H2O2, 100 mg/L for TiO2 and 19.65 min for irradiation time. This condition provided the maximum removal percentage for organic compounds with a minimum cost. The removal efficiency for TOC, DOC and COD were 63.9, 52.9, and 64.7%, respectively. The treatment cost was approximated to be $ 0.71 per one liter of the effluent.
Conclusion: Irradiation and H2O2 concentration had the greatest impact on the cost of the treatment. UV/H2O2/TiO2 process seems to be an expensive process for tertiary treatment of wastewater. However, further investigations are required to evaluate the cost effectiveness of the process for a full scale operation.
Sh Goodarzi, Gh Shams Khoramabadi, M Esmaty, Ma Karami, A Hossein Panahi,
Volume 12, Issue 2 (9-2019)
Abstract
Background and Objective: Wastewater from pharmaceutical industry has high chemical oxygen demand as a result of the presence of organic drugs and antibiotics. In order to meet the environmental requirements, several treatment methods like chemical and electrochemical methods have been widely applied due to their high ability to remove organic compounds from pharmaceutical wastewater. Therefore, the present study aimed to evaluate the efficiency of chemical coagulation/Electro-Fenton treatment method to degrade the organic matter-containing pharmaceutical industry wastewater.
Materials and Methods: The experimental tests were carried out using batch mode. The chemical coagulation process was evaluated as a function of aluminum chloride concentration (25-300 mg/L) and pH (3-10). The effluent from chemical coagulation process was transferred to Electro-Fenton reactor. Effects of H2O2 concentration (100-4000 mg/L), reaction time (up to 120 min), voltage (10-30 V), and pH (3-10) were evaluated. The removal efficiency was determined in term of COD removal.
Results: The results showed that the highest removal of COD in the chemical coagulation was 49% (coagulant dose of 200 mg/L, and pH of 7). In addition, the Electro-Fenton process could be eliminating of 93.5% of COD at the optimum conditions concentration (100 mg/L H2O2, voltage of 20, pH of 3, and contact time of 30 min).
Conclusion: According to the results, it can be concluded that the combination of chemical and electrochemical processes was found to be effective methods for treatment of pharmaceutical wastewater in comparison to the application of each process separately. To reach to the maximum removal efficiency, the environmental parameters should be carefully controlled at their optimum values in each single process.
