فهرست مطالب

Environmental Health Science and Engineering - Volume:3 Issue:1, 2006
  • Volume:3 Issue:1, 2006
  • 72 صفحه،
  • تاریخ انتشار: 1385/01/20
  • تعداد عناوین: 10
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  • S. A. Oke, K. O. Awofeso Page 1
    This paper quantifies the cost involved due to the psychological effect of waste disposal. The major costs are quantified as management and personnel costs. Management costs refer to those associated with awareness, recovery and recycling, taskforce and experimental. On the other hand, personnel costs are related to tax and health. The approach utilized is the algebraic sum of these component costs, since dimensional consistency of the formulation is observed. The results obtained indicate that the framework presented could beneficially add to the tool kit of the environmental decision makers. This would make it possible to generate scenarios that would give the decision maker adequate information before decisions are made. The implication of this research is that intuitive decision-making on cost is replaced with scientific backed up decision making. The idea proposed in this work is new since it provides a unique way of measuring cost of the effects of waste disposal on the stakeholders in the system.
  • F. Mohsenzadeh, J. Nouri, A. Ranjbar, M. Mohammadian Fazli, A. A. Babaie Page 5
    Air pollution is a major problem in the industrial areas. Cement dust is one of the important environmental pollutants. In this study the possibility of dust recycling especially kiln dust which has significant importance regarding air pollution in the cement plant, was examined. Tehran cement factory is one of the most important Iranian factories which is located in Tehran. This factory produces high volume of pollutants that are released to in environment. The possibility of reusing of kiln by pass returned dust has been examined in this factory. Different percentages of kiln by-pass dust of this factory were added to products and outcomes of its presence in parameters such as chemical compound, granulation, primary and final catch time, volume expansion, consumed water and resistance of mortar were surveyed. The result indicated that by adding the amounts of 3-8 dust the mortar resistance increase, but adding more than 15%, the mortar resistance has been decreased. Survey in consumed water proved that adding dust to cement, the trend for consuming water is decreased. After dust addition dust, primary and final catch time were compared in different samples and data which showed decrease in dust added samples. Cements with dust added showed increase in auto clave expansion. Overally, results proved that, the best percentage rate of dust addition to the cement was 15%.
  • R. Alam, J. B. Alam, M. M. Hasan, S. R. Das, K. Rahman, B. K. Banik Page 9
    A study of the water quality conditions of Sylhet city of Bangladesh and its restaurants was carried out to assess risks to human health. The investigation was based on questionnaire survey of restaurants and laboratory tests on water samples obtained from the restaurants, tube wells of the city and Surma River the two main sources of water supply to the city. The test parameters were dissolved oxygen; conductance, hardness, pH, temperature, turbidity, essential and trace elements, dissolved and suspended solids and coliform bacteria. The quality of sanitary facilities and handling of food in the restaurants were also examined. It was found that the drinking water of each restaurant was contaminated with fecal coliforms and 25% restaurants had unsafe levels of iron in the water supply. Improper solid waste dumping was found as one of the reasons of groundwater pollution. Statistical analysis based on Pearson’s correlation coefficient revealed significant correlation between the extent of groundwater pollution and dumping of solid waste effluents in the immediate vicinity of ground water (tube wells). It was observed that 75.69% (coefficient of determination r2= 0.7569) variation in the value of groundwater near the dumping place showed association with variation in the value of water quality within the dumping place. Health risk score for coliform bacteria was 1,474.77, indicating high risk. The results of the study help in enhancing awareness of health hazards of contaminated food among the consumers as well as in drawing attention of health regulatory authorities.
  • H. Hosain Zadegan, M. Sattari, M. H. Zahir, A. A. Allame Page 19
    Induction of lambda phage carring verotoxin1 gene from a verotoxigenic strains of Escherichia coli and released verotoxin1 were studied under environmental factors of shaking and termperature. Verotoxin1 phage in Escherichia coli PA 101 and transductants was confirmed by bacteriophage detection assay. Shaking of culture media and increasing temperature until 42 ºC increased phage particles in supernatants of Escherichia coli PA 101. Our results indicate that environmental factors such as shaking movements in natural inhabitates of bacteria such as river or sewage streams and temperature rise in summer season could be factors in induce and release free verotoxin1 – producing phage particles in nature that in turn could be the source of phage spreading to other related bacteria, and responsible for increased outbreaks of food borne diseases with verotoxigenic Escherichia coli in warm monthes of year in tropical areas.
  • G. R. Nabi Bidhendi, H. Hoveidi, H. R. Jafari, A. R. Karbassi, T. Nasrabadi Page 23
    The disinfecting process has been considered as one of the most important steps in drinking water treatment and improper attention to this process can caused a social disaster. Until now, different methods have been used for drinking water disinfection, such as using the ultra-violet light and adding ozone or chloride. Because of the water sources contaminations, especially in surface water which is in closer contact with different pollutants, adding chloride to water, generally applied all over the world, can cause some adverse impacts on the residential users such as the ones caused by chlorinated chemicals and Trihalomethanes as the secondary products. Regarding to high level of electrical energy consumption and considering resulted costs, this method have not been developed in Iran. This study aimed to explain the drinking water ozonation process opportunities and threats. Usage of ozone is a useful and effective method and could be resulted in high oxidizing property, not producing carcinogens and eliminating bacteria, viruses and other disease-causing elements. On the other hand mentioned method will process in shorter time in comparison with other water treatment methods. There are different techniques for the strategic management as a suitable tool to conduct related environmental management plan. The study management methodology is based on SWOT; so it describes the management functional strategies for ozonation as a suitable drinking water treatment method. Finally, using the QSPM matrix, the hierarchical priority of these strategies was defined. It seems quite important that for the implementation of this process, the foreign experiments in disinfecting drinking water be studied and some proper workforce be trained.
  • R. Rezaei Kalantary, A. Badkoubi Page 31
    Polycyclic Aromatic Hydrocarbons (PAHs) which are introduced into environment are potentially carcinogenic, mutagenic and toxic contaminants. The effect of extractable humic substances (EHS) on bacterial density in bioremediation of anthracene in liquid systems was investigated. The ratio of EHS to anthracene were in two concentrations of 0.35 and 1.05 g dry EHS (with 30% organic matter) per one mg anthracene. In the tests with EHS, an increase in bacterial density even by 8 fold of magnitude was seen in 12-15 days. Then a fast decrease was occurred and prolonged till the end of the test time for the tests that had EHS without anthracene. In the tests which anthracene was the only substrate increasing in bacterial population was not seen. The results showed that up to 21 days the system was free from degradation. So the first increasing in bacterial population showed that EHS might be used as a readily substrate for PAH degraders. The presence of EHS (fulvic and humic acid) can stimulate bacterial community and activity that caused enhancement in anthracene bioremediation.
  • B. Ayati, H. Ganjidoust Page 39
    There are several kinds of anaerobic systems that are widely used for municipal and industrial wastewater treatment. Upflow Anaerobic Fixed Film (UAFF), Upflow Anaerobic Sludge Blanket (UASB) and hybrid reactor (combination of UASB and UAFF) are the mostly used in treating industrial wastewater. As several operational problems have normally been experienced in both UASB and UAFF systems such as long start-up periods and instability, a hybrid reactor has been conceptualized which addressed these problems but retained the positive aspects of these reactors, such as, high cell concentration, good mixing and tolerance to high loading rates. The wastewater has been obtained from Iran Wood Fiber Company which is located in Hassan Rood city, Gilan Province. After period of starting up the reactors and adaptation, the amount of influent COD was being increased stepwise. After the removal rate was reached to its maximum, the next period for increased load was started as after six months, the reactors could accept about 15 Kg/m3.d with high COD removal rate of about 58.5, 58.9 and 65 percent after 3 days detention time. After 5 and 6 months, maximum growth of granule and biofilm was observed. Diameter of 6 mm and mass to surface and COD removal of 0.25 g/cm2 were the highest measured parameters. The comparison of three studied systems showed that their efficiencies were close to each other. As the effective part of UAFF in hybrid reactor was only one third of the reactor, it acted as a separator of solidliquid-gas phases and UASB had the most effect on treatment. In each UAFF and UASB, all percent removal was resulted by each reactor. It can be concluded that hybrid reactor do have the advantages of both systems with at least half of the height of two reactors. Similar results could be obtained with each UAFF or UASB if higher height can be used.
  • S. J. Shahtaheri, M. Khadem, F. Golbabaei, A. Rahimi Froushani Page 45
    Cadmium is an important environmental constituent widely used in industrial processes for production of synthetic materials and therefore can be released in the environment causing public exposure especially around the industrial residence area. For evaluation of human exposure to trace toxic metal of Cd (II), environmental and biological monitoring are essential processes, in which, preparation of such samples is one of the most time-consuming and error-prone aspects prior to analysis. The use of solid-phase extraction (SPE) has grown and is a fertile technique of sample preparation as it provides better results than those produced by liquid-liquid extraction (LLE). To evaluate factors influencing quantitative analysis scheme of cadmium in water samples, solid phase extraction using mini columns filled with XAD-4 resin was optimized with regard to sample pH, ligand concentration, loading flow rate, elution solvent, sample volume (up to 500 ml), elution volume, amount of resins, and sample matrix interferences. Cadmium was retained on solid sorbent and eluted followed by simple determination of analytes by using flame atomic absorption spectrometery. Obtained recoveries of the metal ion were more than 92%. The amount of the analyte detected after simultaneous preconcentration was basically in agreement with the added amounts. The optimized procedure was also validated with three different pools of spiked urine samples and showed a good reproducibility over six consecutive days as well as six within-day experiments. The developed method promised to be applicable for evaluation of other metal ions present in different environmental and occupational samples as suitable results were obtained for relative standard deviation (less than 10%); therefore, it is concluded that, this optimized method can be considered to be successful in simplifying sample preparation for trace residue analysis of Cd in different matrices for evaluation of occupational and environmental exposures.
  • N. Mehrdadi, A. A. Azimi, G. R. Nabi Bidhendi, B. Hooshyari Page 53
    Advanced compact wastewater treatment processes are being looked for by cities all over the world as effluent standards are becoming more stringent and land available for treatment plants more scarce. In this investigation, a new biofilm process for this purpose was studied. The design and operational criteria of a full scale extended aeration activated sludge system was compared with an H-IFAS reactor which has been operated at a pilot scale. The objective was to define the feasibility of using the H-IFAS (Hybrid Integrated Fixed Film Activated Sludge) reactor for upgrading the existing wastewater treatment plants with conventional processes. The results showed that besides the considerable difference between the organic loading of the two processes, H-IFAS reactor has a very good capability to reduce simultaneously the concentration of nitrogen and phosphorus. Organic degradation rate in extended aeration and H-IFAS systems were 0.3 and 6.22 kgCOD/m3.day at 23.48°C, respectively. Nitrification, denitrification and phosphorus removal rate for the H-IFAS reactor were 343.28 g N/m3.day, 338.17 gN/m3.day, and 204.78gPO4-P/m3.day, respectively. At the same conditions, these criteria for extended aeration activated sludge processes were obtained as 75gN/m3.day, 28.5 gN/m3.day and 7 gPO4-P/m3.day), respectively.
  • Z. Kechrid, F. Dahdouh, R. M. Djabar, N. Bouzerna Page 65
    The contamination of water by metal compounds is a worldwide environmental problem. Concentration of metals is widely related to biochemical values, which are used in diseases diagnosis due to environmental toxicity. The sub-chronic combined effects of nickel and cobalt on body weight gain and biochemical parameters were determined and compared with those of Ni (2+) or Co (2+) alone in 6 weeks male albino (Wistar) rats. Animals were given drinking solutions of NiSO4 6H2O [Ni (II) cation, LD50/2] or CoSO4 6H2O [Co (II) cation, LD50/2]. For the combined treatment (Ni + Co), the rats received both Ni (II) cation (LD 50/2) and CO (II) cation (LD50/2). Nickel and cobalt treatment decreased body weight gain. The nickel sulphate increased also the glucose level. The two heavy elements produced hepatic and renal damage, characterized by increased activity of alanine and aspartate transaminases (GPT, GOT) and alkaline phosphatase. However lactate dehydrogenase activity (LDH) was decreased. In addition, serum urea, serum creatinine, serum total protein and serum bilurebin concentrations were significantly elevated. In general the combined effect of Ni-Co was slightly less toxic than nickel or cobalt alone, suggesting antagonism between these toxicants.