International Journal of Environmental Health Engineering
Volume:2 Issue: 3, Apr 2013

 This study was conducted to evaluation humic acid adsorption from aqueous solution using pumice modified with cationic surfactant. 

 The pumice modification was carried out with cationic surfactant of hexadecyl trimethyl ammonium bromide (HDTMA-Br) with a concentration of 3 mmol/l for 48 h using a 150 rpm shaker. The chemical structure of pumice was determined using X-ray fluorescence (XRF) and X-ray diffraction (XRD). For evaluation of the effective parameters, the adsorption of humic acid onto modified pumice was conducted with batch experiments. Humic acid concentration was determined by photometry on 254 nm. Langmuir, Freundlich, and Temkin models and pseudo-first and pseudo-second-order kinetics were used for adsorption isotherm and kinetics studies. 

 The results showed that humic acid adsorption increased as its initial concentration, the adsorbent dosage, and the contact time increased. Increase in pH within the regions 3-12 resulted in the reduction of adsorption efficiency while the optimum adsorption occurred at pH = 3. The adsorption data followed the Langmuir model (R2 = 0.99) and second-order kinetic model (R2 = 0.99). Maximum experimental adsorption and theoretical adsorption capacity of the adsorbent were 22.5 and 29 mg/g, respectively. The Langmuir constant coefficient (b) was determined as 0.8 L/mg. 

 It was understood from the results of this study that adsorption onto modified pumice is efficient in performance and thus affordable technology for the elimination of humic acid from the polluted water supply.

 The biodegradability of oil containing polychlorinated biphenyls (PCBs) from electrical transformer by the anaerobic sequencing biofilm batch reactor (ASBBR) with was assessed. 

 Two anaerobic sequencing batch biofilm reactor (ASBBR) containing polyurethane foam cubes as inert support was used. The reactors were operated for 310 days at 35 ± 2°C. The reactors with a total volume of 7 L, 5 L effective volume and 3.5 L for gas production, were operated in a cycle per day. The effect of operational parameters including organic loading rate, PCBs loading rate, co-substrate type, initial PCBs and COD concentration was evaluated. 

 The results point to admirable reactors stability and over 95% efficiency in PCBs removal, with effluent PCBs concentration of lower than 10 mg/L. However, degradation rates increased as the initial concentration of PCBs as increased. The average of COD removal efficiency by two ASBBR reactors was more than 92% that corresponding to > 9 μg/L of effluent COD. In over all operation, average of biogas production in R1 was 5.7 ± 2.2 L/d and maximum produced biogas was 8.02 L/d at 310 day. The kinetic studies revealed that second - order kinetic model described the COD removal by ASBBR reactors from synthetic wastewater better than two other kinetic model. 

 Therefore, this investigation demonstrated that the ASBBR have good potential for biodegradation of oil containing PCBs, despite variation of influent PCBs and organic loading rate (OLR).

 In this study, the efficiency of peracetic acid (PAA), sodium hypochlorite (NaOCl) and combination of both disinfectants for disinfection of stabilization pond effluent was assessed. 

 The samples was collected during four months. All samples were analyzed as triplicate according to the Standard Methods. Microbial tests were carried out to total coliform (TC), fecal coliform (FC) and fecal streptococci (FS) . Also, the physical characteristics such as the total suspended solids, and also chemical oxygen demand (COD) and biochemical oxygen demand (BOD) were analyzed. Results : In this study, the application of combined disinfectants lead to reduction of total coliform, fecal coliform and fecal streptococci from 2.8×10 5 , 2.2×10 5 and 7.1×10 4 to 1.6×10 3 , 5×10 1 and 1.9×10 2 MPN/100 ml, correspondence to 2.55, 3.64 and 1.83 log removal value (LRV), respectively. 

 The study demonstrated that application of combined PAA and NaOCl in disinfecting the effluent of the stabilization pond will promote the efficiency of disinfection process in inactivating the coliform group bacteria and fecal streptococci.

 In this study, the effect of arsenite and arsenate removal in synthetic water by coagulation using ferric chloride (FeCl 3 ) as coagulant and chitosan as coagulant aid were investigated. b>

A conventional jar test apparatus was used to evaluate the coagulation process. The effects of different conditions of pH (5.5-9), coagulant doses of FeCl 3 0-60 mg/l), Arsenic speciation (As (V) and As (III)), Chitosan as coagulant aid, and initial arsenic concentrations (0.2-2 mg/l) to Arsenic removal was investigated by considering the residual arsenic and iron after coagulation. 

 The finding showed that the optimum pH for FeCl 3 as a coagulant to As (V) and As (III) removal was 7. As (V) removal efficiency of 90% or higher by FeCl 3 alone were achieved for initial As (V) concentration 0.2-2 mg/l at optimum dosages (15-30 mg/l). In contrast with As (V) removal, about 60% of the As (III) were removed in comparable conditions. The optimal dosage of chitosan was determined to be 0.5 mg/l. When chitosan (0.5 mg/l) was used as coagulant aid with FeCl 3 , the efficiency removal was enhanced almost to 100% and 80% for As (V) and As (III) removal, respectively. The optimum dosage of FeCl 3 was reduced, especially at low initial concentration of arsenic. 

 Chitosan as natural coagulant aid improved arsenic removal efficiency by coagulation process using FeCl 3 . This method can be used for regions with drinking water contaminated with initial arsenic concentration less than 1 000 μg/l.

 The aim of this study was to evaluate the effects of gamma irradiation on the disinfection of the water and wastewater from Isfahan wastewater treatment plants. 

Materials and Methods :

 Using a 60 CO gamma radiation machine with emission rate of 405.38 CGy/min, water and wastewater samples were irradiated at doses of 20-160 Gy and 80-240 Gy, respectively. Microbial cultures were performed on the samples to assess the pre- and post-irradiation coliforms content. 

Results : 

The results of microbial tests showed that approximately 100% of the total and fecal coliforms in water samples were inactive at 160 Gy dose of gamma radiation. At a dose of 240 Gy, gamma-ray efficiency for inactivation of the total coliforms in the effluent was different, considering the sample quality. The efficiency for secondary effluent, polished, and filtered samples was 56, 83, and 64%, respectively. In this case, reduction of fecal coliforms was 46, 58, and 81%, respectively. The effective reduction of the coliforms in the effluent samples (80-50%) was also observed at doses of 120-240 Gy. According to the dose-response curves, as the radiation dose increases, the inactivation of the coliforms increases linearly. 

 At gamma doses used in this study, the coliforms were removed completely. But for wastewater samples, although the removal efficiencies were above 80%, the environmental standards related to microbial parameters were not satisfied. Therefore, it is necessary to use higher doses of gamma radiation.

 The aim of this study was to determine fluoride levels in drinking water of Mianeh city and to evaluate decayed, missing, and filled teeth (DMFT) index in children between 6 and 9 years old. 

 This cross-sectional research was carried out on all sources of drinking water including 14 groundwater sources in Mianeh city. A total of 56 samples were taken from all wells during four seasons of 2009 and analyzed with colorimeter "SPADNS" method with DR 2500 spectrophotometer set17. 

 The results show that the means of source fluoride concentration in spring, summer, autumn, and winter seasons were 0.295 ΁ 0.039 mg/l, 0.47 ΁ 0.17 mg/l, 0.48 ΁ 0.18 mg/l, and 0.4 ΁ 0.06 mg/l, respectively. This means that the concentration of fluoride in all sources was below national standards, but they were in permissible range proposed by WHO. In addition, the DMFT index of the children between 6 and 9 years old in Mianeh city was higher than national mean. 

 Considering the low fluoride concentration in water sources of Mianeh, it was proposed that a chemical compound such as sodium fluoride be added to provide fluoride ion. It seems that the low fluoride levels in supplied water have a significant effect on higher DMFT index in children of the subjected community.

 The aims of present study is to determine the level of exposure to physical risk factors of work related repetitive movements in the upper limbs among the artisans in Isfahan, using occupational repetitive actions index and the Nordic Questionnaire. 

 In this cross-sectional study, the study population consisted of 94 males employed in Artisan production. The tools that be used for assessing physical ergonomic risk factors among artisans was Nordic Questionnaire and OCRA index. The different handicraft tasks and work activities included: Simple etching, embossing, reticular embossing, enameling, tiling, illumination, inlay, copper smithing and, miniature painting have been chosen for the study. The Study was carried out on the both left and right hands. The results were analyzed by statistical tests included Chi square, Kruskal Wallis and one-way variance analysis. 

 The highest OCRA index score was related to simple etching job, and the other tasks such as embossing, copper smithing, reticular embossing, tiling, miniature painting, and illumination were in lower risk category. Our finding showed that there are a significant difference between OCRA scores of the various jobs (P value < 0.001), and also the relationship between OCRA index and the type of jobs was statistically significant (P value < 0.001). Risk level in the right hand was significantly higher than the left hand (P value < 0.001). Moreover, in both right and left hands, OCRA index was different among several types of jobs (P value < 0.001). 

 Our assessment showed that in overall there are different physical risk factors among artisans which make them susceptible to musculoskeletal disorders.

 The purpose of this research was to determine the effects of soils contaminated with lead, zinc and cadmium on the high concentration of these metals in the urban air.

 In this regard 63 samples of soil and 18 air samples were taken at sampling grids from various regions of the city. After digestion of samples, the extracted liquids were analyzed by atomic absorption spectroscopy. 

 The concentration of lead, zinc, and cadmium in the soil samples were not higher than international standards, but was two to three times as high in the air as that found in European countries and U.S. Results also showed a correlation between concentration of these metals in the city soils and their increased level in the city air through dust and wind, particularly in the northern parts of the city, whilst no such correlation is found in the southern parts, which could be due to wind blowing dust polluted with these metals from heavy industries located at south-west of Isfahan. 

 As, at present time, there is a ban on consumption of leaded petrol throughout the city, two main probable sources of lead pollution in the air of the city of Isfahan are dust from contaminated soil and also, presence of a large steelworks industry in the south-west of Isfahan which is in the direction of south-west to north-westerly winds.

 The aim of this study is predicting the effluent COD of UASB reactors with flowing mathematical models. 

 Weak industrial wastewater of the township, after passing screening unit, grit removal chamber and equalization tank, entered UASB reactor with volume of 144 m 3 (Length and width: 6 m; useful depth: 4 m). Analyses of laboratory parameters were done in accordance with water and wastewater standards. 

 The reactor start-up started with hydraulic retention time of 14.4 d and organic loading rate of 0.04 Kg COD/m 3 .d or 0.02 Kg BOD 5 /m 3 .d which in 200 days, hydraulic retention time reached to 0.9 d and organic loading rate reached to 0.85 Kg COD/m 3 .d or 0.45 Kg BOD 5 /m 3 .d eventually, that the highest COD and BOD 5 removal efficiencies were observed up to 70% and 64%, respectively in the hydraulic retention time of 0.9 d. In the kinetic evaluation, the equations for effluent COD concentration prediction were obtained after calculating kinetic coefficients of Y, K d , K, K S and μmax in the Monod model; β and μmax in the Contois model; α, β and K 2(S) in the second-order Grau model and K B and U max in the modified Stover-Kincannon model. 

 The effluent COD concentration of reactor is a function of influent COD concentration of reactor in the modified Stover-Kincannon and second-order Grau models that have highest correlation coefficients while, it is a function of reactor's solids retention time in Contois and Monod models.

 The object of the study was to identify chlorine demand factorsin water and chlorine in Kanbebein City water and eliminating of them. 

 Concentration of free and combined residual chlorine with the methods presented in the book "Standard Methods for Water and Wastewater Examination" were measured. Other parameters such as: Temperature, TOC, TDS, pH, EC, nitrate, ammonia, total hardness, alkalinity, iron and manganese were also examined before and after of chlorination. 

 The Highest chlorine decay constant in the short time were in water well was 0.895 mgL -1 h -1 and the least amount of it was 0.0097 mgL -1 h -1 and the Highest chlorine decay constant in the long time were in water well was-0.092Lmg -1 h -1 and the least amount of it was-0.0017 Lmg -1 h -1 that correlated with nitrite, ammonia and iron concentration. 

 The factors that affected short-time chlorine decay constant (k 2 ) were nitrite, ammonia and iron and The factors that affected on long-time chlorine decay constant (k 2 ) were Nitrite, ammonia and iron. The material removal techniques for them were the use of natural resins, zeolite, ion exchange, membrane and aeration methods, oxidation and sedimentation, and filtration.

 The aims of this study were to produce activated carbon from refuse derived fuel (RDF) and to examine its efficiency in dioxins and furans (PCDD/F) removal for application in the adsorptive processes of waste incineration. 

 In the present study the RDF was carbonized at 600°C to produce char and the char was then steam activated at 900°C to generate activated carbon (AC). The efficiency of the produced AC in PCDD/F removal from simulated flue gas was investigated using a bench scale static-bed reactor. Experiments were conducted under flue gas stream at 275°C using a standard flyash (BCR-490) as a source of PCDD/F. The PCDD/F content of the exhaust gas was trapped by XAD-II resin, and after extraction and clean-up processes, were analyzed using a GC coupled with a triple quadrupole mass spectrophotometer (MS). 

 The results showed an overall reduction of 85% and 43% in the flue gas concentration of PCDD and PCDF, respectively, which compared favourably with a commercial AC. In addition, reduction was varied throughout the congener groups of these compounds. 

 The AC derived from the pyrolysis of RDF therefore shows potential as a control material for dioxins and furans in waste combustion process.

Aims : 

The aim of this study was to measure the concentration of Pb, Cd, and Ni in the effluent of Isfahan north wastewater treatment plant as well as in the soils and agricultural products irrigated with that effluent. 

 In the selected area around of the treatment plant, treated wastewater, soil, wheat, wheat stem, and corn were sampled. The samples were digested with nitric acid procedure and analyzed with a flameless atomic absorption spectrometer. 

 The results shows the average concentration of Pb, Cd, and Ni was 0.02, 0.006, and 0.062 mg/1 in the effluent; 13.9, 1.67, and 2.23 μg/g in the deep soil; 0.366, 1.02, and 0.79 μg/g in the wheat; 0.67, 0.86, and 1.32 μg/g in the wheat stem; and 6.37, 0.62, and 0.52 μg/g in the corn, respectively. 

 The average concentration of Pb, Cd, and Ni were less than the critical limits in the effluent (0.01, 0.2, and 5 mg/1) and the amounts were currently within the permitted range for soil (2-100, 10-1000, and 10-7 mg/g). In some farming lands, the amounts were beyond the permitted range for plants (1-10, 1-10, and 0.2-0.8 mg/g). There was a meaningful relationship between the average concentration of these metals and the kind of sample. In addition, the accumulation of heavy metals in all samples irrigated with wastewater was more compared to samples irrigated with groundwater. So irrigation of farmland with effluent should be monitored. Farmers in the area must be advised to grow shrubs with smaller roots rather than big-rooted plants like sugar beet.