Showing 6 results for Naddafi
M Kermani , K Naddafi , M Shariat , A.s Mesbah ,
Volume 2, Issue 1 (2 2004)
Abstract
Apparently, breathing clean air is of significant importance to human beings and thus attention to what enters our body through inhalation is on the increase. Tehran’s air pollution has received considerable media coverage in recent years: Since particulate matter (TSP and PM10) is one of the important pollutants in this city, an attempt was made to study TSP and PM10 concentrations and to make a qualitative assessment of air using the Air Quality Index (AQI), with TSP and PM10 sampling both daily and on a monthly basis. Shariati Hospital district was selected as study area from 22 December 2001 to 20 April 2002. To determine the amount of TSP and PM10 according to EPA and WHO standards, 61 samples were taken for TSP and 61 samples for PM10 with High Volume Sampler. The results indicated that: • As for TSP and PM10, the period extending from 20 February to 20 March (Esfand) was the most heavily polluted one in this study. The cleanest spell was observed from 21 March to 20 April (Farvardin). • Saturdays and Mondays were the most polluted days of the week for TSP and PM10 and Fridays were the cleanest. • As for TSP, In 51 percent of the samples the Air Quality Index (AQI) was below 100 (AQI<100) and in the remaining 49 percent, AQI was above 100 (AQI>100). • In the case of PM10, in 75.5 percent of samples the Air Quality Index (AQI) was below 100 (AQI<100) and in the remaining 24.5 percent AQI was above 100 (AQI>100).
M Mokhtari , K Naddafi , A.h Mahvi , S Naseri ,
Volume 3, Issue 3 (3 2005)
Abstract
There is a need for simple and inexpensive water supply systems in small communities, mainly because of high costs and water resource shortages. Ceramic filters used as a Point-of-Use (POU) system could serve as a safe and inexpensive means for supplying water. In this research we looked at the possibility of using Iranian traditional ceramics as filters for drinking water, bearing in mind the importance of ceramic filters as a POU system. A number of parameters relating to water quality were measured before and after filtration through a ceramic pipe wall. We used ceramic pipes made of clay (with 90% purity). It turned out that ceramic filters are capable of eliminating indicator microorganisms and turbidity to a considerable degree. They can also remove 70% of the water's color. But this system could not eliminate Dissolved Solids, Electrical Conductivity, Hardness and the Nitrate ion content of water. Using Mann-Withney U Test and T- Test, it is confirmed that increasing the thickness and number of ceramic pipes is not effective for improving some water parameters. This research showed ceramic filters can be useful for household water treatment in places where there is microbial pollution or high turbidity.
R Saeedi , K Naddafi , R Nabizadeh ,
Volume 5, Issue 2 (3 2007)
Abstract
Background and Aim:We studied the biosorption of lead(II) and cadmium(II) from aqueous solutions by the brown algae Sargassum sp. biomass in a batch system.
The heavy metal uptake was quite rapid, reaching 88-96% of the equilibrium capacity of biosorption in 15 minutes.
Material and Methods: Kinetic data were analyzed using the pseudo first-order, pseudo second-order, and saturation and second-order rate equations.
Results: The pseudo second-order and saturation rate equations gave the best fit with the experimental data(R2 > 0.99). The data obtained from experiments of single-component biosorption isotherm were analyzed using the Freundlich, Langmuir, Freundlich-Langmuir and Redlich-Peterson isotherm models. The Redlich-Peterson equation was found to provide the best fit with the experimental data (R2 > 0.99). Also the other models described the isotherm of lead(II) and cadmium(II) biosorption with relatively high correlation coefficients (R2 > 0.93).
Conclusion: Using the Langmuir model, the maximum uptake capacities (qm) of Sargassum sp. for Pb2+ and Cd2+ were 1.70 and 1.02mmolg-1, respectively.
R Nabizadeh, K Naddafi, M Mohebbi, M Yonesian, A.m Mirsepasi, S Oktaie, M Faghihi ,
Volume 5, Issue 4 (5 2008)
Abstract
Background and Aim: The scattered state of the rural populations- in terms of both the distance between villages and the distance between residential units within a single village- has made the task of supply, distribution and monitoring the quality of water a difficult one. In this study we looked at the bacteriological quality as well as access to safe potable water in selected villages of Tehran Province. This research started in February 2006 and ended in July the same year.
Materials and Methods: In this cross-sectional field study, sampling points were specified on the basis of the populations of the villages served by the Tehran Rural Water and Wastewater Company. After systematic sampling, the specimens were transferred to the laboratory for testing. Data were analyzed using the SPSS and Microsoft Excel software packages.
Results: Drinking water contamination with E. coli was observed in 5.99% of the villages. The degree of contamination was highest in the districts of Pakdasht, Savojblagh and Damavand, with rates of 33.34, 13.69 and 13.32 percent respectively. For 99.36% of the Tehran rural population the turbidity was lower than the standard value of 1053 set by the Iranian Institute of Standards and Industrial Research. Values in Savojblagh and Varamin were relatively higher, with rates of 96.51% and 99.30% respectively. Given the standard value of 1053, the residual chlorine levels were unacceptably low for 92.39% of the rural residents, with figures in the districts of Pakdasht, Damavand and Robatkarim reaching 75.67, 85.45 and 83.98 percent respectively.
Conclusion: Based on WHO guidelines concerning the microbial quality of water published in 2006, the average indicator for lack of E.coli in rural water of Tehran was 94.01%, i.e. at an excellent level. Levels were good for Damavand and Savojblagh, low in Pakdasht and excellent in all other districts.
A.r Mesdaghinia , J Nouri , A.h Mahvi , F Vaezi , K Naddafi , M Ansarizadeh ,
Volume 7, Issue 4 (27 2010)
Abstract
Background and Aim: The aims of this study was to explore the feasibility of improving efficiency of the wastewater treatment system of the Fars Pegah Dairy Industries (FPDI) and propose ways to upgrade it in 2006-2007. The FPDI wastewater treatment system was of a successive anaerobic-aerobic type using anaerobic stabilization ponds and conventional and extended aeration activated sludge. Due to improper design and operation, it did not meet the required standards with regard to disposal to the surrounding cultivated land.
Materials and Methods: To overcome the problem and eliminate the bad smell, modifications were made, such as changing the entries and exits of the ponds, adjustment of the activated sludge process, and converting the conventional activated sludge F/M to a step-feed activated sludge shift. The efficiency of the system was assessed before and after these modifications
Results: The efficiency of the system to eliminate biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total dissolved solids (TDS), total suspended solids (TSS), total coliform, and fecal coliform increased from 82.42%, 86.87%, 64.18%, 20.23%, 54.56% and 50.87% to 97.34%, 98.61%, 90.4%, 28.44%, 90.09% and 89.95%, respectively.
Conclusion: The findings show improvements in the efficiency of the wastewater treatment system due to the changes made in it. It was also observed that efficiencies of the feed-step aeration and the extended aeration are similar. This means that application of the extended aeration in the treatment system of the plant would result in waste of money and energy.
M.r Zare, K Naddafi,
Volume 8, Issue 4 (20 2011)
Abstract
Background and Aim: Specific and unique characteristics of nanoparticles may entail specific and unique hazards. In addition, they may also exhibit toxicity under certain conditions. This study was conducted to investigate the toxicity of phenol-exposed and phenol-unexposed nano-TiO2 and nano-Fe/TiO2 particles.
Materials and Methods: Stock solutions of the afore-mentioned nanoparticles were prepared at different concentrations and a sample of each was exposed to phenol. This was followed by exposing Daphnia Magna to the phenol- and non-phenol-exposed nanoparticles. LC50, NOEC and the concentrations at which mortality rates were 100% were determined 12 to 96 hours after exposure, while for the determination of the mortality rate of Daphnia the Probit model in SPSS version16 software was used.
Results: The results revealed that (1). The 48-hr LC50 values for phenol-unexposed nano-TiO2 and nano-Fe/TiO2 particles were 2705 and over 15000 mg/m3, respectively. The corresponding values for the phenol-exposed samples were 414 and 1253. (2). The 48-hr NOEC values for the phenol-exposed TiO2 and FeTiO2 were 41 and 789, respectively, the corresponding values for unexposed samples being 1253 and over 15000 mg/m3. (3). In addition, the 48-hr 100% mortality rates for phenol-unexposed nano-TiO2 and nano-Fe/TiO2 particles were, respectively, 1253 and over 15000 mg/m3, while for the phenol-exposed samples the corresponding rates were 1090 and over 2108.
Conclusion: With regard to 48-hr LC50, the findings show that the toxicity of both nano-Fe: TiO2 and TiO2 increases as a result of exposure to phenol, the increase being 12-fold for the former and 6.5-fold for the latter. In general, however, based on LC50, it can be said that the toxicity of Fe:TiO2 nanoparticles, which has better catalytic characteristics, is lower in comparison to TiO2 nanoparticles. Thus, using Fe:TiO2 in preference to pure TiO2 should be investigated further, as it will be less hazardous to the environment.
