Showing 34 results for Amin
H. Hashemi, M.m. Amin, B. Bina, H. Movahedian Attar, H. Farrokhzadeh,
Volume 3, Issue 1 (3 2010)
Abstract
Backgrounds and Objectives:Today, due to health, environmental and economical problems, of chlorine application, UV radiation is better option than chlorine for disinfection of effluent. The aim of this study was disinfection of secondary effluent with UV radiation.
Materials and Methods: Two types of UV disinfection system including low pressure (LP) and medium pressure (MP) was used to disinfection of Isfahan North Wastewater Treatment Plant (INWWTP) effluent without pretreatment. Single and combined lamps were operated to evaluate the removal of total and fecal coliforms (TC and FC), and fecal streptococcus (FS). TSS, iron, hardness, UV absorption and transmittance were analyzed in order to observe the fouling of the quartz sleeves.
Results: After using LP lamp with dose of 161 mws/cm2, TC and FC content was declined to standard level (1000 TC, and 400 FC/100ml). In addition, disinfection with MP lamp was led to FS content of 400 MPN/100 mL. Combination of LP and MP, with dose of 460 mws/cm2 could be met the environmental requirements of TC & FC, and the FS count was reached to 400 MPN/100 mL with dose of 237 mws/cm2. Maximum photo-reactivation percentage of coliforms after LP and MP lamps were appeared 15 and 3 percent respectively, while it was not observed for FS.
Conclusion: High fluctuation in secondary effluent quality of INWWTP mainly TSS concentration was caused to decline of the UVT value. Therefore, disinfection of effluent by LP, MP and even combined both systems are not applicable in conventional UV dose. Hence, using advanced process unit before UV disinfection system is necessary for removal of TSS.
M.m Amin, B Jaberian, M Saadani, R Hadian, G.r Bonyadi Nejad, A Khodabakhshi,
Volume 3, Issue 2 (6 2010)
Abstract
Backgrounds and Objectives: Powdered Activated$ carbon is known as a suitable absorbent for organic materials. The aim of this research is evaluation of Powdered Activated-Carbon (PAC) efficiency in removal of Dissolved Organic Carbon (DOC) in water treatment in Isfahan.
Materials and Methods : The increase of PAC for DOC reduction has done in three paths in the Isfahan water treatment plant (WTP). These paths including: 1) Intake up to entrance of WTP 2) Intake to exit ofWTP 3) Between entrance and exit of waterworks. The paths were simulated by the Jar test system. Then DOC and UV254 absorption were analyzed and SUVA parameter for samples and activated-carbon adsorption isotherm was calculated.
Results: The injected PAC doses of 20,40,60,80 and 100 mg/l caused decreasing in DOC and UV254 absorption in every sample in all paths. The average of this decrease, from intake to WTP.s exit (second path) was the greatest 69.8± 3.9%and the commonWTP process had capability of removing 35% of DOC. The first path also showed that PAC can reduce 33± 2% DOC of raw water by itself. Activated-carbon absorption results were adhered from Freundlich adsorption isotherm.
Conclusion: In the third path therewas lessDOCremoval efficiency than exceptedwhen Activated- Carbon injected in rapid mixed basin with coagulant. Powdered activated carbon porosity reduction due to effect of coagulant can be the reason for this issue.Also according to different paths, the point of intake is more suitable for powdered activated carbon addition.
P Atabakhsh, M.m Amin, H Mortazavi, M Yaran, A Akhavan Sepahi, A Nouhi, M Jalali,
Volume 3, Issue 3 (4 2010)
Abstract
Backgrounds and Objectives:Total and Fecal coliforms (TC and FC), heterotrophic plate count (HPC), were counted by microbiological method and E.coli O157:H7 were detected through immunological and Real time PCRmethods inwater intake and all of units of Isfahanwater treatment plant (IWTP).
Materials and Methods: The microbial profile including TC, FC, and HPC, were monitored and turbidity and total organic carbon were analyzed in 8 locations of water intake, and unit operation and processes of IWTP, including, inlet, sedimentation, ozonation, and filtration and finished water. Immunological method through anti-serum kits and molecular method of RT-PCR were used to detect E.coli O157:H7 in the 8 locations and also the sludge of the sedimentation basin and filters backwash water of IWTP.
Results: Survival of E.coli O157:H7 in sludge sample of sedimentation basin was indicated by formation of agglutination particles in immunological method and through indicator probes in the RT-PCR method. However, E.coli O157:H7 was not detected in water samples of other units of IWTP. The removal percent of TC, FC, and HPC were: 59.5, 49, and 54.8 % in sedimentation basin 66, 45.8, and 57 % in ozonation: 98.8, 98, and 78.8 in the filtration and 96, 100, 91% in disinfection, respectively.
Conclusion: This study approved the existence of the pathogenic coliform, E.coli O157:H7 in the
sludge of sedimentation basin. Absent of E.coli O157:H7 in the finished water indicates that the existing units of IWTP could eliminate these pathogenic bacteria, before reaching the final units of the plant, including the filters and disinfection.
A.r Rahmani, M Solaimany Aminabad, Gh Asgari, F Barjasteh Askari,
Volume 3, Issue 4 (8 2011)
Abstract
Backgrounds and Objectives: High level of nitrate ion in the water resources cause some health and environmental problems. The aim of this research is to study nitrate removal by Zero-Valent Magnesium (ZVM) and MgCl2-modified pumice from aqueous solutions.
Materials and Methods: The pumice granules were modified by MgCl2 . The removal of nitrate was studied in a batch system. The pH, initial nitrate concentration and sorbent mass parameters and the Langmuir and Freundlich models were studied in the sorption of nitrate onto the pumice. The ZVM was also used in a bach system and the previous parameters were studied.
Results: The removal efficiencies of nitrate by ZVM at the the initial pH of 3, 5 and 7 with controlling the pH were 70%, 40% and 30% ,respectively. These values are much higher than the values of the condition during which the pH was not controled. The nitrate removal efficiency increased by increasing of initial nitrate concentration in a constant molar ratio of Mgo/NO3. The removal efficiencies of nitrate by the modified pumice at the the initial pH of 3, 6.5 and 10 (when pH kept under control) were 49%, 29% and 16%, respectively. By increasing of the initial nitrate concentration the removal efficiency increased. The values of R2 for the Langmuir and Freundlich models were 0.944 and 0.810, respectively. The sorption process Fitted well the Langmuir model with a monolayer sorption capacity of 0.68 mg/g.
Conclusion: The modified pumice had lower efficiency than ZVM in the removal of nitrate ion and its usage is not considerably affected bye the pH in comparison with ZVM. The pH of the solution should be cansiderd as a main controling parameter to get an optimum efficiency in the nitrate-ZVM process.
M Hadi, R Shokoohi, A.m Ebrahimzadeh Namvar, M Karimi, M Solaimany Aminabad,
Volume 4, Issue 1 (24 2011)
Abstract
Background and Objectives: widely use of antibiotics as therapy and uncontrolled discharge of them to receiving waters increased the percentages of antibiotic resistant bacteria in various environments which may cause problems in therapy. The aim of this study was to investigate the antibiotic resistance of E. coli, K. pneumoniae and P. aeruginosa bacteria isolated from urban and hospital wastewaters. Nine antibiotics namely Chloramphenicol, Ciprofloxacin, Trimethoprim Sulfamethoxazol, Gentamycin, Ceftizoxime, Nalidixic Acid, Ceftazidime, Ceftriaxon and Cefalexin were investigated in this study.
Materials and Methods: through a cross-sectional descriptive study the isolation of bacteria from hospital and urban wastewater samples was performed by microbiological identification techniques. The resistance to nine antibiotics was tested by application of the standard disc diffusion technique and zone-size interpretation chart of Kirby-Baeur. Non-parametric Mann-Whitney test was used to assessing two environments differences.
Results: The resistance percentage of E. coli to studied antibiotics was significantly less (ranged from 1.81 to 51.02%) than the resistance percentage of P. aeroginosa (ranged from 3.57 to 61.76) and K. pneumoniae (ranged from 6.45 to 91.83%). the highest resistance to antibiotics studied was for K. pneumonia in comparison with others. E. coli, K. pneumonia and P. aeroginosa bacteria showed the highest resistance to CAZ, SXT and CN, respectively. The study showed the resistance rate in hospital wastewater is more than urban wastewater.
Conclusion: Easy access and uncontrolled usage of antibiotics cause discharge of antibiotics to wastewaters and consequently diminish the drugs' effectiveness. High concentration of antibiotic and diversity in wastewater of hospital in comparison with urban wastewater causes to transfer resistant agents between bacteria and increased the multiple resistances.
M Heidari, H Saffari Khouzani, M.m Amin, M Ghasemian, E Taherian, L Attari, A Hassanzadeh,
Volume 4, Issue 2 (9 2011)
Abstract
Background and Objectives:Antibiotics and hormones are excreted with other wastes following their influences on bodies.These substances can disturbed treatment process by their entery to the wastewater. In this study the inhibitory behavior of antibiotics Ofloxacin and Ciprofloxacin and hormone stradiol 17- valerat have been investigated on Specific Methanogenic Activity (SMA) of anaerobic biomass.
Materials and Methods: Twenty one SMA tests were done using 120-mLvials in batch mode. In each vial, substrate, biomass and biogas were occupied 66, 17, and 17 % (v/v), respectively. Each test longed in range of 15-30 days. Produced methane was measured by gas replacement with 2N KOH solution as CO2 absorbent.
Results: In this study, at the concentrations of 200, 500 and 1000 mg/L of antibiotic Ofloxacin, the methane production reduced to 45, 76 and 88 percent, respectively. Reduced methane production of 68, 81 and 88 percent was observed in Ciprofloxacin concentrations of 100, 200, and 500 mg/L, respectively. Cumulative methane at the concentrations of 0.1, 1, and 5 mg E2 /L was 66, 90, and 121 mL, respectively
Conclusion: Antibiotic Ciprofloxacin at concentrations similar to the antibiotic Ofloxacin have a greater inhibitory effect on specific methanogenic activity of anaerobic biomass. Also, the hormone E2 at lower concentrations showed more inhibitory effect than other two antibiotics Ciprofloxacin and Ofloxacin.
M Malakootian, M. M Amin, H Jaafari Mansourian, N Jaafarzadeh,
Volume 4, Issue 4 (2 2012)
Abstract
Background and Objectives: Microbial fuel cells are the electrochemical exchangers that convert the microbial reduced power, generated via the metabolism of organic substrate, to electrical energy. The aim of this study is to find out the rate of produced electricity and also treatment rate of simulated wastewater of food industries using dual chamber microbial fuel cell (MFC) without mediator and catalyst.
Materials and Methods: MFC used in this study was consisted of two compartments including anaerobic anode chamber containing simulated food industries wastewater as synthetic substrate and aerobic cathode chamber containing phosphate buffer, respectively. These two chambers were separated by proton exchange membrane made of Nafion. Produced voltage and current intensity were measured using a digital ohm meter and the amount of electricity was calculated by Ohm's law. Effluent from the anode compartment was tested for COD, BOD5, NH3, P, TSS, VSS, SO42- and alkalinity in accordance with the Standard Methods.
Results: In this study, maximum current intensity and power production at anode surface in the OLR of 0.79 Kg/m3.d were measured as 1.71 mA and 140 mW/m2, respectively. The maximum voltage of 0.422 V was obtained in the OLR of 0.36 Kg/m3.d. The greatest columbic efficiency of the system was 15% in the OLR of 0.18 Kg/m3.d. Maximum removal efficiency of COD, BOD5, NH3, P, TSS, VSS, SO42- and alkalinity, were obtained 78, 72, 66, 7, 56, 49, 26 and 40%, respectively.
Conclusion: The findings showed that the MFC can be used as a new technology to produce electricity from renewable organic materials and for the treatment of different municipal and industrial wastewaters such as food industries.
Fahim Amini, Masoud Yunesian, Mohammad Hadi Dehghani, Nima Hosseni Jazani, Ramin Nabizadeh Nodehi, Maasoumeh Moghaddam Arjomandi,
Volume 5, Issue 1 (6 2012)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Nosocomial infection is the cause of deaths, morbidity, higher costs
and increased length of stay in hospitals. Correct and appropriate use of
antiseptic and disinfectants play an important role in reducing infections. In
this study the efficacy of antiseptics on bacteria causing hospital infections
has been studied.
Materials and Methods: This study was conducted in the laboratory of Imam Khomeini Hospital of Uremia.
In this study the Antimicrobial activity of Descocid, Korsolex basic, Mikrobac
forte and persidin 1% was studied against bacteria causing hospital infections
such as Enterobacter aeruginosa 1221 (NCTC 10006), Staphylococcus epidermidis
(PTCC: 1435 (Cip81.55) and Pseudomonas aeruginosa Strain PAO1. Sensitivities of
bacteria were determined by Minimum inhibitory Concentration (MIC) and Minimum
bactericidal Concentration (MBC) antiseptics. In the second stage, the
concentration of antiseptics was prepared according to the manufacturer's
suggested protocol and the effect of antimicrobial agents were studied at the
certain concentration and contact time.
Result: All
disinfectants (Descocid, Korsolex basic, Mikrobac forte) concentration and
contact time, Accordance with the manufacturer's brochure, had inhibitory
effect on all bacteria. That this is consistent with the manufacturer's
brochure. Persidin one percent in concentration of from 2 and 4 V/V % and
exposure time 5 minutes could not inhibit the growth of bacterial. But at
concentrations of 10 and 20% respectively 15 and 30 minutes exposure time, all
three types of bacteria can be inhibited, which is consistent with the
manufacturer's claims.
Conclusion: In this
study, the efficacy of antiseptics was determined with the Micro-dilution
method recommended by the NCCLS. Korsolex basic, weakest antiseptics (the
highest MIC) for the inhibition of three bacteria was determined. But Between
all four antiseptics (according to manufacturer concentration), Only one percent
Percidine 2 and 4 V/V % in consumer
dilution and 5 minutes exposure time failed to inhibit the growth of
Pseudomonas aeruginosa, Staphylococcus epidermidis and Enterobacter aeruginosa.
Ensieh Taheri, Mahdi Hajian Nejad, Mohammad Mahdi Amin, Hossein Farrokhzadeh, Maryam Hatamzadeh, Marzieh Vahid Dastjerdi,
Volume 5, Issue 1 (6 2012)
Abstract
AR-SA
MicrosoftInternetExplorer4
Background and Objectives: Aerobic sludge granulation is an
advanced phenomenonin which its mechanisms have not been understood.
Granulation can be a promising and novel biological wastewater treatment
technology to eliminate organic and inorganic materials in future. High
salinity is a parameter which leads to plasmolisatian and reduction of the cell
activity. This could be a problem for biological treatment of the saline
wastewater. Aerobic granule was formed and investigated during this study.
Materials and Methods:
This study is an intervention study on the treatment of wastewater with
500-10000 mg/L concentration of NaCl by sequencing batch reactor. Asynthesized
wastewater including nutrient required for microorganism's growth was prepared.
Input and output pH and EC were measured. Range of pH and DO varied between
7-8, and 2-5 mg/L, respectively. SEM technology was used to identify graduals
properties.
Results: In terms of color, granules divided
into two groups of light brown and black. Granule ranged in 3-7mm with the
sediment velocity of 0.9-1.35 m/s and density of 32-60 g/L.Properties of
granules were varied. Filamentous bacteria and fungi were dominant in some
granules. However non filamentous bacteria were dominant in others. EDX
analysis indicated the presence of Ca and PO
4.
Conclusion: Granules
with non filamentous bacterial were compact and settled faster. Presence of
different concentrations of salinity leaded to plasmolysis of the bacterial
cells and increased concentrations of EPS
in the system as a result of
which granulation accelerated
.
Ramin Nabizadeh, Masoud Binesh Brahmand, Kazem Naddefi, Ali Reza Mesdaghiniya,
Volume 5, Issue 1 (6 2012)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Guilan province, with unique
environmental values of the Caspian Sea is located in
the southwest of Caspian Sea. Disposal of
untreated domestic sewage, industrial and agricultural surface water cause
pollution of the Caspian Sea region and
endanger the health of swimmers. This study performed to determine the
microbial contamination of coastal water in Guilan.
Materials and Methods: In this work, 21 sampling point
in the Caspian Sea littoral provinces of
Guilan were selected and microbial contaminations were assessed using microbial indicators of fecal and total
coliform. Parameters such as pH, temperature, and turbidity also monitored
during the year. In this study, 122 samples were taken and then analyzed by
statistical software.
Results: The results showed that the average values of total
coliform and fecal coliform were 234.8 and
60 MPN per 100 ml, respectively. The fecal pollution appeared to be high
in some stations. Also significant relationship between temperature, turbidity
and microbial contamination was observed (P< 0.05).
Conclusion: The results revealed high total coliform in the two
stations. The average fecal coliform of six stations were higher than the local
standards.
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Mahmood Alimohamadi, Ebrahim Molaee Aghaee, Ramin Nabizadeh Nodehi, Gholam Reza Jahed, Sasan Rezaee, Akbar Goldasteh, Shahrokh Nazmara, Hassan Aslani,
Volume 5, Issue 2 (13 2012)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Heavy metals including antimony and cobalt as two
contaminant factors leach from polyethylene terephthalate packages into water
under some conditions. Therefore, their detection was concerned at different
storage conditions.
Materials and Methods: Five time-temperature treatments were carried out for 5 water samples. Storage
conditions were defined as following: at outdoor and sunlight ambient
temperature, room temperature, and at 40˚C at different intervals for 8 weeks,
at 65˚C for 6 weeks and 80˚C for 7 days. Detection was performed by ICP-AES
method and the data analysis was processed by SPSS software.
Results: Antimony
concentration increased by storage time at all temperatures and for all
samples, however enhancing proportion was different in samples. At outdoor,
40˚C and room temperature, concentration increase was below the MCL by the end
of storage period. But at 65˚C and 85˚C, antimony concentration exceeded MCL by
study time and the difference between samples 4 and 5, for example, was
significant (p≤0.05). Cobalt concentration at the beginning and during the
study was also too less and lower than the detection limit.
Conclusion: By
increasing temperature and time, leaching of antimony into water increases.
Moreover, sunlight has effect but not noticeable at the temperature of present
study. In this study, blue or clear packaging had no significant effect on
antimony leakage (P>0.05).
Ramin Nabizadeh Nodehi, Hassan Aslani, Mahmood Alomohammadi, Reza Nemati, Kazem Naddafi, Maryam Ghany,
Volume 5, Issue 2 (13 2012)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Irrigation of agricultural crops using wastewater will
increase, in some cases, their growth by 40 to 60 percent. However, this has a
high risks for human health because of the presence of higher number of
pathogenic organisms. The main purpose of this study was to investigate the
feasibility use of Fenton and modified Fenton with copper for the disinfection
of raw wastewater.
Materials and Methods: After primarily laboratory physicochemical and biological analysis, the
disinfection process was performed in three different phases in each process.
First, the disinfectants were injected separately, then we performed
disinfection using Fe++ and cu++ ions combined with hydrogen peroxide in order
to determine synergistic effect of each catalyst. Direct method was used for
fecal coliforms counting.
Results: Hydrogen
peroxide maximum efficiency for inactivation of fecal coliforms was only
0.66log inactivation. Fenton and modified Fenton with copper ions showed a
remarkable effect on the bacterial inactivation so that Fenton and modified
Fenton with 1 and 2 mg/l of Cu++ inactivated coliforms by 4.73, 3.28, and 4.88
log respectively.
Conclusion: Application of HP alone for the disinfection of raw wastewater is not
practicable due to low observed efficiency. However, its combination with ions
such as Fe++ and Cu++ increases HP performance in disinfection and has a
notable synergistic effect on HP
disinfection power, where, in the presence of each catalyst, hydrogen
peroxide can reduce the fecal coliforms of raw wastewater to meet the Iranian
Environmental Protection Agency Standards.
Fatemeh Momeniha, Ramin Nabizadeh Nodehi, Mohammad Sadegh Hassanvand, Amir Hossein Mahvi, Kazem Naddafi,
Volume 5, Issue 2 (13 2012)
Abstract
MicrosoftInternetExplorer4 Background and Objective: Dioxins and Furans are dangerous and highly toxic compounds entering to the environment from natural and manmade sources. Having high stability and half-life, these compounds remain for a long period in the medium and bring about severe effects on human beings and the environment. The aim of this study was to identify dioxins and furans emission sources in Iran and to estimate their contribution in emission rate.
Materials and Methods: First, we identified the emission sources of dioxins and furans and then necessary data was gathered by referring to the authorized organizations and filling the prepared UNEP questionnaires. We used Excel software to analyze the data collected.
Results: According to the results obtained, total dioxins and furan emission in Iran in 2010, was 1957 g TEQ/yr out of this amount, 705.8 g TEQ is emitted to the atmosphere and 643.2 g TEQ is residual ash. Therefore, dioxins and furans emission rate was 26.4 µg TEQ/capita in Iran. The most rates of emissions were associated with uncontrolled open burning (732.8 g TEQ/yr) and ferrous and nonferrous metal production (635.7 g TEQ/yr) such as cupper, iron, and steel.
Conclusion: Our findings showed that the emission rate of Dioxins and Furans is much higher in Iran compared with other countries and appropriate management strategies are required to control these dangerous pollutants.
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Mohamad Taghi Samadi, Roghaye Nourozi, Mohamad Hadi Mehdinejad, Reza Aminzadeh,
Volume 5, Issue 4 (15 2013)
Abstract
Backgrounds and Objectives: Determination of arsenic(As) in drinking water has received increasing interest due to its detrimental effects on health. The aim of this research is to investigate effect of coating coral limestone using aluminum sulfate as an adsorbent on the arsenic(V) removal efficiency from aqueous solution.
Materials and Methods: In this laboratory scale study, we prepared coral lime granules using mesh 30 during several stages. Then, we investigated the arsenate removal efficiency under different conditions and changing main factors including pH, contact time and amount of no coated and aluminum sulfate-coated adsorbent. Moreover, we fitted our results with Langmuir and Freundlich models and kinetic data with pseudo- first order, pseudo- second order and modified pseudo- first order models.
Results: We found that increasing pH from 3 to 10 at arsenate concentration of 500 ppb and 5 g/l adsorbent and 120 min contact time, removal efficiency for no coated and coated adsorbent was reduced from 100 to 86.2% and from 100 to 92.2% respectively. Increasing concentration of both adsorbents from 1 to 5 g/l at contact time 120 min increased the removal efficiency from 76 to 99.2% and from 66.3 to 91.1% respectively. Arsenate removal efficiency was directly proportional with the amount of adsorbent and contact time and reversely proportional with the initial concentration of arsenate and pH. The removal efficiency of the coated adsorbent was more than uncoated adsorbent. Langmuir was the best sorption isotherm model for arsenate in these two processes and absorption kinetic was well described with second order models.
Conclusion: Excellent removal efficiency, cost-effectiveness process, and lack of environmentally harmful substances make application of the Persian Gulf offshore corals a reasonable adsorbent to remove environmental contaminants such as arsenate.
Mahran Mohammadian Fazli , Jalil Nassiri , Ramin Nabizadeh, Mohammad Reza Mehrasbi,
Volume 6, Issue 1 (5-2013)
Abstract
Backgrounds and Objectives: Medical waste management is one of the important issues in solid waste managment in each community. This research was carried out to study the quantity, quality and the management practices of solid wastes of hospitals in Zanjan City in 2011.
Materials and Methods: In the present study, the hospital wastes were categoried and weighted into four main categories. Waste management pattern was studied based on a checklist extracted from national guidelines. Then, hospitals were ranked from very poor to excellent classes. For data analysis, Excel soft ware was used.
Results: Waste generation rate was on average 2.402± 0.163 Kg/bed.day in the studied hospitals. The generation rate of domestic waste, infectious waste, sharp wastes, and chemical - pharmacological waste was 1.432±0.059, 0.926±0.096, 0.029±0.0055, and 0.015±0.002 kg/day.bed respectively. The status of the waste management practices was determined as average.
Conclusion: Waste generation rate in the hospitals of Zanjan was lower compared with the expected average value in other cities (e.g. 2.71 Kg/bed.day in Tehran). The percentage of medical waste in Zanjan hospitals was 34, which is higher than W.H.O. recommendations. Therefore, it is strongly recommended to reform and monitor certain solid waste management practices in order to reduce health and environmental issues.
Bijan Bina, Mohamadmahdi Amin, Mohamadreza Zare, Ali Fatehizadeh, Mohsen Mohseni, Mahdi Zare, Ali Toulabi,
Volume 6, Issue 2 (9-2013)
Abstract
Background and Objectives: Toxicity assessment of material related to nanotechnology is
necessary before excess development of this industry. On the other hand, specific
characteristic of nanomaterials can be used in disinfection of other material. In
this study toxicity and antibacterial properties of nano-TiO2 and nano-CuO
were investigated with four bacterial species in solid media.
Material and Methods: Stock
suspension of nanoparticles (10g-TSS/L) was diluted using Muller Hinton Agar to
achieve 5-6000mg-TSS/L concentration. We prepared three Petri dishes for each concentration
and refined bacteria were cultured on these Petri dishes. After culturing of these
bacteria on the media containing nanoparticles, growth inhibition was determined.
According to this data, 50% growth inhibition (EC50), no observed effect
concentration (NOEC) and 100% growth inhibition were determined.
Results: Our results showed
that toxicity of TiO2 is more than CuO in solid media. In this regard,
nano-TiO2 EC50 for Escherichia coli, Bacillus subtilis, Staphylococcus
aureus, and Pseudomonas aeruginosa was calculated 181, 571, 93 and 933mg-TSS/L respectively.
These figures for nano-TiO2 were 2550, 1609, 946, and 1231mg-TSS/L respectively.
Conclusion: This study
showed that compared with other bacteria studied, E. aureus due to high sensitivity
and E. coli due to high resistance to both TiO2 and CuO nanoparticles
are more proper as bioindicator in toxicity test and antibacterial test respectively.
Amir Hossein Mahvi, Noushin Rastkari, Ramin Nabizadeh Nodehi, Shahrokh Nazmara, Simin Nasseri, Mahboobeh Ghoochani,
Volume 6, Issue 3 (12-2013)
Abstract
Background and Objectives:Chlorination is the most common method of water disinfection. Chlorine reaction with natural organic compounds nor removed completely during treatment process would result in forming disinfection byproducts. Followed by trihalomethanes, Haloaceticacides are the second main byproducts of chlorination in water. The research works conducted in Iran have assessed trihalomethanes. Hence, this is the first time we are reporting haloacetic acids in Iran.
Materials and Methodology: We collected samples from surface water resources and treated water in Tehran for six consecutive months (first half, 2010). We measured temperature, pH, UV adsorption at 254 nm and TOC in each surface water sample and analyzed pH, residual chlorine, and haloacetic acids in the treated water samples.
Results: We found that TOC in surface water resources is 3.6-4.42 and 1.78-2.71 mg/l in spring and summer respectively. Moreover, haloacetic acids concentration was found to be 41.7-55.56 and 34.83-43.73 μg/l in spring and summer respectively.
Conclusion: Our results revealed that concentration of NOM, TOC, and HAAs was more in spring than summer. In addition, concentration of HAAs was depended up on NOM and TOC. Considering maximum permeable concentration of HAAs (60 μg/l) by EPA, it can be claimed that concentration of HAAs was less than the maximum permissible level in all of the samples. However, the immanency of the monitored values to the standard values can be a warning for concerned authorities in water industry.
Zhila Moradi-Khatoonabadi, Yahya Maghsoudlou, Hamid Ezzatpanah, Morteza Khomeiri, Mehdi Aminafshar,
Volume 6, Issue 4 (3-2014)
Abstract
Background and Objective: Milk and milk products are very suitable medium for growing microorganisms (e.g. Bacillus cereus). B. cereus is spore former bacilli, which easily survives during pasteurization and makes several problems in dairy industries. The aim of this study was to investigate aerobic spore and B. cereus of receiving raw milk from three UF plants. Materials and Methods: Samples were gathered from raw milk transport tankers arrived to plants during 30 days in winter. Also, the swab test was used for detection of B.cereus residual on milk contact surfaces. Results: High contamination level of aerobic spores (AeSC) and especially B.cereus were found in most samples compared with the criteria established by national and international standards. Although total viable count (TVC) in samples from industrial farms (IF) was lower than those from traditional farms (TFs) and milk collection centers (MCCs), considerable AeSC and B.cereus were transmitted to the UF plants from IFs. The highest and lowest TVC and B.cereus were found in samples from IFs and MCCs, respectively. In addition, our investigation in IFs revealed that teats contamination to soil and feces, as well as contaminated bedding might were the most important sources of B. cereus and AeSC of raw milk. Moreover, the results of swab tests confirmed that the “cleaning in place” system may not remove B.cereus effectively. Conclusion: It seems that for classifying raw milk quality, AeSC might be used as a more effective quality factor than TVC. Management commitment is effective to improve quality by balance between the amount and quality of receiving raw milk. This leads to the lower contamination in dairy plants and final products.
Mahdi Sadeghi, Kazem Naddafi, Ramin Nabizadeh,
Volume 7, Issue 2 (10-2014)
Abstract
Background and objective: Perchloroethylene is a chlorinated hydrocarbon used as a solvent in many industries and services activities such as dry cleaning and auto industry as degreasing. We carried out a bioassay using Daphnia Magna in order to determine the ecological effects of wastewater treatment through applying advanced oxidation processes (ultrasonic, ultraviolet irradiation and hydrogen peroxide processes) for removal of perchloroethylene. Materials and Methods: Due to the sensitivity of Daphnia and reports indicating this species is the most sensitive aquatic invertebrate to a variety of organic compounds, toxicity of perchloroethylene and its intermediate degradation products during applying different processes was tested using Daphnia. Lethal concentration (LC50) and toxic units (TU) were determined. In to determine toxicity of perchloroethylene, its stock solution was prepared at a concentration of 100 mg/L. Then, nine samples each containing 0 (control), 5, 10, 20, 30, 40, 50, 75, and 100% by volume of the primary stock solution were prepared. To determine the toxicity of the intermediate products of perchloroethylene by ultrasonic, photolysis, photolysis with hydrogen peroxide and photosonic processes, an initial concentration of perchloroethylene for each reactor (100 mg/L) was taken. All experiments were carried out at the Laboratory of Microbiology, Faculty of Health, Tehran University of Medical Sciences, Iran. Results: It was found that the 24 h LC50 for perchloroethylene on Daphnia Magna was 35.51 mg /L. The 48 h, 72 h and 96 h LC50 of perchloroethylene were 28.058, 21.033, and 19.27 mg/L respectively. Toxicity of perchloroethylene was decreased after oxidation processes. Conclusion: The toxicity after hybrid processes was lower than the single processes. The toxicity reduction was the same during all time period. Hence, the hypothesis of reducing toxicity of the intermediate products of perchloroethylene degradation after the abovementioned processes is acceptable. It is noteworthy that although there are different intermediate compounds in the effluent of various chemical oxidation processes, , but they are less toxic compared with the original perchloroethylene this may be due to the partially concentration of intermediate products that will decrease toxicity.
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.
