Journal of Research in Environmental Health
Year:2019 | Volume:5 | Issue:2|Papers Count:6

Background and Aim: Reducing the amount of sludge produced by the biological treatment of active sludge is of great importance. The main task of dewatering unit is to separate water from excess sludge. The aim of this study is to determine the effect of ultrasonic waves on coagulants in improving the sludge dewatering process and increasing solid content of sludge cake. Materials and Methods: This is an experimental study performed in batch laboratory scale. During the two seasons, 12 samples were taken at 15 days’ intervals. Variables include ultrasound density (0. 375, 0. 75, 1, 1. 3 and 2. 5) in watts per ml, Time (1, 5, 10, 15 and 30) in minute, and specific energy input (208, 1041, 2083, 3124 and 6249) in kilojoule on kilo total suspended solids. The effects of ultrasonic waves on coagulants were investigated by using Particle Size Analizer (PSA). Results: The optimum amount of solid content of sludge and capillary suction time (CST) was equal to 26. 4 percent and 86 seconds in sonification time of 5 minutes and specific energy input of 1041 kj/kg TS. By applying ultrasonic waves, d10, d50, d90 and average particle size amount were equal to 6. 3, 44. 2, 24. 4 and 28. 84 micrometers respectively. Conclusion: Ultrasound waves create pores in the physical structure of the polymers and the increase of cationic surface charge increases the adsorption of particles and made larger flocs and can increase the solid content of sludge and improve sludge dewatering process.

Background and Aim: The present study was performed to investigate trend and prediction of changes in some quality parameters of Gamasyab river water using multivariate statistical methods and time series. Materials and Methods: In this research, the annual means of some qualitative parameters related to a 6-year statistical period in two Pol-Chehr and Doab stations were used. At first, the factors controlling chemistry of Gamasyab river were determined using Ternary and Gibbs diagrams. Then, to determine a linear relationship between multidimensional variables, Canonical correlation coefficients were used. Finally, the changing trend of water quality parameters in next 5-years was predicted. Results: At Pol-Chehr station, qualitative parameters show an upward trend except for pH. While at Doab, all qualitative parameters show a downward trend except for Mg and SO4. Based on Ternary and Gibbs diagrams, water dominant facies are Ca-Mg-HCO3 and the main factor controlling water chemistry is water-rock reaction at both stations, respectively. Results showed that the chemical parameters of HCO3 and Mg at Pol-Chehr with canonical coefficients of 0. 938 and 0. 933 are in the first group and Na with coefficient of 0. 845 is situated in the second category. While in Doab station, chemical variables HCO3 and Ca with coefficients of 0. 945 and 0. 0789 are placed in the first group, and Na and Cl with the coefficients of 0. 930 and 0. 800 are in the second group, respectively. First and second group origins of canonical variables can be related to dissolution of limestone and evaporative deposits. Prediction results of the water quality parameters changes in Gamasyab river for the next 5 years showed that an increase in all the parameters except for pH at Pol-Chehr station. While except for Mg and SO4, all quality parameters will decrease at the Doab station. Conclusion: Water-rock reaction is the most important factor affecting Gamasyab river water chemistry.

Background and Aim: The communities have been faced the environmental challenges by dust particles as an important part of air pollution that are emitted into the atmosphere every day by chimney of factories and power plants out. The aim of this study was to determine the quality and quantity of industrial dust around the Yazd Steel Company to control and supervise the industrial dust to make the better environmental condition. Materials and Methods: In this study, according to the wind direction, the falling dust particles, were collected and weighted in two sediment stations before and after the company from 1/2/2016 to 30/4/2016. The sampling was done by MDCO. Then, the taken samples transferred to an elemental analysis laboratory, and the amounts of dust-forming elements were measured by XRF device. Results: Based on the obtained results, the maximum and minimum levels of the concentrations of falling dust particles were 32. 9g/m2 on March for, 0. 0014 g/m2 on February for SiO2 and SrO respectively. the major elements and chemical compounds of dust included: SiO2، CaO، CO2، Al2O3، MgO، Fe2O3، K2O، Na2O، SO3، TiO2، Cl، P2O5، MnO، ZnO، Pt، Au، SrO. Conclusion: The results of statistical tests demonstrated that there was a significant difference between the amounts of these elements before and after the company. Therefore, proper management and more accurate monitoring are necessary to protect the environment in this industry.

Background and Aim: Major Dam construction projects have increased due to widespread climate change, as a result of increased drought, human population growth and, consequently, increased global demand for energy and water. However, without comprehensive research, a large project such as a dam will have many irreversible and unpredictable effects on the environment. In this paper, the environmental impacts of Eyvashan dam in two phases of construction and exploitation on biological, physical-chemical, economic-social, cultural and strategic environments have been identified and studied. Materials and Methods: In the study of the environmental impact assessment of the Eyvashan dam with regard to development and evolution, as well as the abundant use of matrices in construction projects, the modified Leopold matrix method and the rapid impact assessment matrix have been used. The field survey and questionnaire were used to evaluate the construction and operation activities on the environmental components. Results: The results showed that the most negative effects in both construction and utilization phases were in both Leopold modified matrix and the rapid impact assessment matrix related to the physical-chemical environment and the most positive effects of the socio-economic environment for both phases. Conclusion: By comparing the many positive effects of construction and exploitation of the dam in terms of socio-economic status, the construction of the dam can be considered as an appropriate alternative to the physicalchemical negative effects. Also, in the results of both matrices, there was a very suitable adaptation matrix that can confirm the accuracy of the results in the environmental assessment of the Eyvashan dam in two stages of construction and operation.

Background and Aim: The high concentration of nitrate in drinking water can be detrimental to health. It can be reduced to nitrite in children’ s Stomach and lead to methemoglobinemia. Therefore, the removal of nitrate from polluted waters is necessary. The purpose of this study is to determine the effectiveness of walnut shell adsorbent in nitrates removal from aqueous solutions. Materials and Methods: This experimental study was conducted in a batch laboratory-scale reactor. The walnut shell was collected and burned in the furnace at 700 ס C in 1 hour and sieved in 20-100 mesh. The optimum values of pH, contact time, adsorbent dosage and concentration of nitrate were determined in lab scale conditions. The nitrate concentration was measured in wavelengths of 220 and 275 nm by the spectrophotometer. Also, pHpzc of the absorbent was determined. Results: The results showed that the optimum pH was 9. In higher and lower proportions of pH, the removal efficiencies were increased and decreased respectively. The removal efficiency was increased until 120 minutes; however, the percentage of removal was reduced after 120 minutes. Adsorption efficiencies were increased and decreased by increasing the adsorbent dosage and the concentration of nitrate, respectively. At optimal condition, the nitrate removal efficiency was 78%. Conclusion: The result of the present study shows that walnut shell can be used as an effective and cheap adsorbent for nitrate removal from aqueous solutions, and the alkaline pH is more efficient for removal process.

Background and Aim: House flies are able to transmit pathogenic organisms from infected materials to human. The role of the flies in the transmission of many diseases has been demonstrated. This study was conducted to determine the bacterial contamination of M. domestica flies in various sources of Joybar city. Materials and Methods: A total of 384 household flies were collected from five sources including urban and rural solid wastes, hospital campus, coastal areas and slaughterhouses. Samples were transferred to the microbiology laboratory of the school of public health in some sterilized glass containers, and standard tests were carried out to isolate and identify bacterial species. Results: Escherichia coli was the dominant species in the samples. From all of the samples, 46% E. coli, 19% Staphylococcus aureus, 9. 98% Staphylococcus epidermidis and 16. 66% Enterobacter Aerogenus were isolated. Conclusion: The results of this study confirmed that the presence of these insects in the public places and different parts of the environment is regarded as a disturbing agent, and vector of pathogens. Since public spaces should not be a source of contamination, the implementation of the sanitation programs and control of these insects seems to be so necessary to create a safe and healthy environment.