Environmental Health Engineering and Management Journal

73-79

Authors: Nematollah Jafarzadeh, Maryam Ravanbakhsh *, Kambis Ahmadi Angali, Ahmad Zare Javid, Darioush Ranjbar Vakil Abadi, Shirin Ardeshirzadeh

Background: Internal corrosion and the formation of scale in water distribution pipes are the most important problems for an urban water distribution system. Physical, chemical, or biological factors can lead to these two processes. Internal corrosion and scale formation can impact health, economy, and aesthetics. This study assessed the physicochemical quality parameters and evaluated the potential for corrosion and scale formation in drinking water at the distribution systems of 5 selected cities in Bushehr province (Kangan, Dashtestan, Dashti, Bushehr, and Ganaveh) from 2009-2012. Methods: This study was carried out based on laboratory data collected from monthly samplings of tap water in the Water and Wastewater Company of Bushehr province during the years 2009-2012. Internal corrosion and scale formation rates were calculated using the Ryznar, Langelier, Aggressive, and Puckorius indices. Results: The results of the Ryznar, Puckorius, Aggressive and Langelier indices indicated that the drinking water in the 5 selected cities of Bushehr province was corrosive. Moreover, the majority of parameters used to determine water quality exceeded Iran’s national standards. Conclusion: It is concluded that there is problem of water corrosion and scaling in drinking water of distribution systems in selected cities.

93-99

Authors: Zeynab Akbarlou, Vali Alipour *, Mohsen Heidari, Kavoos Dindarloo

Background: Considering the severe health and environmental hazards caused by the entry of diazinon toxin into water resources, its removal is very important. Given the high costs of imported adsorbents, this research attempted to evaluate, for the first time, the efficiency of Iranian activated carbon in removing diazinon from aqueous solutions. Methods: In this batch experimental study, the effects of contact time (5-90 minutes), adsorbent concentration (0.5-30 g/L), initial concentration of diazinon (5-50 mg/L), and pH (3-10) on the adsorption of diazinon onto the activated carbon were evaluated. Concentrations of diazinon were measured using a high pressure liquid chromatography (HPLC) instrument. The specific surface area of the adsorbent was determined by BET and BJH methods. The experimental adsorption data was analyzed using Langmuir and Freundlich isotherm models. Pseudo first-order and pseudo second-order kinetics models were employed to determine kinetics. Moreover, data was analyzed using SPSS version 19, and Pearson correlation and analysis of variance (ANOVA) tests were performed at a significance level of 0.05. Results: The optimum contact time, sorbent dose, and pH were 30 minutes, 10 g/L, and 5, respectively. The adsorbent could adsorb diazinon with a removal efficiency of 92.5% under optimum conditions (initial concentration: 20 mg/L). The experimental data was better described by the pseudo-second order kinetic and Langmuir isotherm. A maximum adsorption capacity of 71.4 mg/g was calculated by the Langmuir isotherm model. Conclusion: With respect to the high adsorption capacity of Iranian activated carbon, this sorbent can be considered an efficient adsorbent for the removal of diazinon from aqueous solutions.

109-115

Authors: Mahmood Mahdi Barbooti *

Background: Oxytetracycline (OTC) is a widely-used antibiotic; metabolism studies indicate only partial assimilation of it inside the body. Traditional wastewater treatment plants cannot remove OTC, and this results in the release of considerable amounts of the drug into aquatic environments. There is much concern over the role of residual antibiotics in the development of new generations of bacteria with modified resistance to the antibiotics. The present work investigated the possibility of OTC sorption on river sediments. Methods: Seven sediment samples were collected from various locations and depths of the Passaic River in New Jersey. The texture, clay, extractable iron, and organic matter contents of the sediments were determined. Pyrolysis-gas chromatography-mass spectrometric (Py GC-MS) analysis indicated the presence of 3 categories of organic materials: petroleum hydrocarbons, anthropogenic, and plant residual materials. The sediment samples were equilibrated with OTC solutions for 24 hours followed by centrifugation and syringe filtration. The residual OTC contents were determined by high performance liquid chromatography. Results: It appeared that 35%-60% fractions of OTC were retained by the sediments. The sorption capacity values of the sediments were correlated with clay content, organic matter content, and available iron. A poor correlation was found between adsorption capacity and clay content in the presence of organic matter and iron. Meanwhile, a relatively strong correlation was found between adsorption capacity with the iron, R2 = 0.7499, and organic matter contents of the sediments, R2 = 0.7899. Thus, the sorption of OTC on sediments is governed by all constituents. Conclusion: It was concluded that the antibiotic-sediment interaction is controlled mainly by the organic matter and iron contents.

123-129

Authors: Salar Omid, Zahra Derakhshan, Mehdi Mokhtari *

Background: Due to the lack of a proper waste management system, Tehran Municipality Region 20 is facing economic and environmental problems such as the high costs of a disposal system and source pollution. Life cycle assessment (LCA) is a method for collecting and evaluating the inputs, outputs, and potential environmental impacts of a product system throughout its life cycle. The current study purposed to provide a stable and optimized system of solid waste management in Tehran Municipality Region 20. Methods: The LCA method was used to evaluate various scenarios and compare the effects on environmental aspects of management systems. Four scenarios were defined based on existing and possible future waste management systems for this region. These scenarios were considered with different percentages for source separation, composting, recycling, and energy recovery. Results: Based on the results of this study, Scenario 4 (source separation [14%] + composting [30%] + municipal recycling facility [MRF] [20%] + energy recovery [10%] + landfilling [26%]) was found to be the option with the minimum environmental impact. In the absence of government support and sufficient funds for establishing energy recovery facilities, the third scenario (source separation [14%] + composting [30%] +MRF [20%] + landfilling [36%]) is recommended. Conclusion: The results acquired from this investigation will confirm the belief that LCA as an environmental device may be successfully used in an integrated solid waste management system (ISWMS) as a support tool for decision-making.