Background: Cadmium (Cd) is a heavy metal that is widely utilized in industries and contaminates soil and groundwater. There are several environmental problems related to cadmium, therefore, the technical and economic methods of removing Cd are of great importance. So this study was conducted to evaluate the efficiency of a type of plant to remove the Cd from aqueous environments. Methods: In this cross-sectional study, the adsorption of Cd examined from synthetic aqueous solutions was evaluated using the seed powder of Miracle tree (Moringa oleifera). In this order, 70 samples were prepared and tested. To determine the absorption of metals by this sorbent, different pH (5, 7 and 9), sorbent dose (1.5, 3 and 5 g), temperature (20, 30 and 45°C), concentrations of Cd (2, 5, 10 and 20 ppm) and exposure time (0, 30, 60, 120, 180 and 210, 240 minutes until reaching equilibrium) were experimented upon, using atomic absorption spectrometer (Varian-AA240FS), and the residual concentration of Cd was read. Results: The highest removal efficiency of Cd under optimum condition (180 minutes and pH of 5) was 70%. The optimum sorbent dose was 1.5 g, which achieved a removal efficiency of 75%. The removal trend was an inverse of Cd concentration. The adsorption of Cd using M. oleifera fitted into both models (Freundlich and Langmuir), but was somewhat better fitted with the Freundlich model and followed pseudo second order kinetics. Conclusion: The results indicated that under optimized absorption conditions (pH: 5, sorbent: 1.5 g, temperature of 45°C, Cd concentration of 2 ppm and exposure time of 180 minutes), the removal rate of Cd was 80% and thus the nature of the adsorption reaction was endothermic. Based on the results obtained, the studied sorbent could be introduced as a practical sorbent to the Industrial society. In some sorbents, for M. oleifera, the adsorption capacity was determined based on the results obtained, and the adsorption capacity was found to be 0.1 mgg. This means that, in order to remove any pollutant (in this case Cd), 10 times of the sorbent weight need to be added.
Background: Water resource management is a strategic issue in Qom city. Water scarcity is one of the most critical concerns of industrial estates. This study aimed to evaluate wastewater management in the Shokuhieh industrial park of Qom province in 2013.
Methods: This is a descriptive cross-sectional study done by visiting the industrial units in person, completing questionnaires and analyzing the results. The questionnaire had 25 questions, including general information, the status of water supply, treatment and consumption, wastewater production, reuse or discharge of produced wastewater and the status of wastewater treatment and discharge of effluent. The industrial units evaluated were active with over 50 personnel and numbered 44 in total.
Results: The water suppliers in the industries included network (70.5%), network and reverse osmosis (RO) (22.5%), network and tanker (2.4%) and tanker (4.6%). 63.63% of the industries had water treatment systems. 19.5% reused wastewater and 31.8% performed pretreatment before discharge of wastewater. The discharge sites of water treatment units’ effluent included the absorption well (17%), greenbelt (18%) and sewer (65%). Discharge sites of sanitary wastewater in 50% of the industries was sewer and in 50%, it was absorption well. The discharge sites of processed wastewater was reuse (2%), sewer (52%) and absorption well (46%). Discharge sites of exiting effluent from pretreatment units in the industrial park, included sewer (85.5%), transport by tanker (7.1%) and absorption well (7.1%). The type of pretreatment process in 35.7% of the industries was chemical and in 64.3%, it was septic tank.
Conclusion: The results of this study showed that pre-treatment is not done in most industries and wastewater reuse is performed in few industries. The main method of wastewater disposal in industries was by discharge into the sewer and absorbent well.
Background: Air pollution and concerns about health impacts have been raised in metropolitan cities like Tehran. Trend and prediction of air pollutants can show the effectiveness of strategies for the management and control of air pollution. Artificial neural network (ANN) technique is widely used as a reliable method for modeling of air pollutants in urban areas. Therefore, the aim of current study was to evaluate the trend of sulfur dioxide (SO2) air quality index (AQI) in Tehran using ANN.
Methods: The dataset of SO2 concentration and AQI in Tehran between 2007 and 2013 for 2550 days were obtained from air quality monitoring fix stations belonging to the Department of Environment (DOE). These data were used as input for the ANN and nonlinear autoregressive (NAR) model using Matlab (R2014a) software.
Results: Daily and annual mean concentration of SO2 except 2008 (0.037 ppm) was less than the EPA standard (0.14 and 0.03 ppm, respectively). Trend of SO2 AQI showed the variation of SO2 during different days, but the study declined overtime and the predicted trend is higher than the actual trend.
Conclusion: The trend of SO2 AQI in this study, despite daily fluctuations in ambient air of Tehran over the period of the study have decreased and the difference between the predicted and actual trends can be related to various factors, such as change in management and control of SO2 emissions strategy and lack of effective parameters in SO2 emissions in predicting model.
Background: Chlorophenols are classified as priority toxic pollutants. These acidic organic compounds present a serious potential hazard for human health and aquatic life. Chlorophenols accumulate in water, soil and air due to high stability, and impart an unpleasant taste and odor to drinking water and can exert negative effects on different biological processes. Among the different methods of removal, adsorption process by low price adsorbents, such as fly ash (FA) is common. Therefore, in this study, the effects of oxidation of FA as modified adsorbent were investigated when the adsorption of 2-chlorophenol (2-CP) was increased.
Methods: This experimental study was conducted from March to September of 2013. FA obtained from Zarand power plant (located in Kerman province) was oxidized with potassium permanganate. Effective factors on the oxidation of FA, such as temperature, oxidation time and concentrations of oxidizers were optimized. Raw sewage of Zarand coal washing plant was tested under optimal conditions. All tests were carried out according to the standard methods book for the examination of water and wastewater.
Results: Optimal condition for the preparation of oxidized FA was obtained at 70°C, 1 hour, and 1 mM of potassium permanganate concentration. The absorber obtained was able to remove 96.22% of 2-CP under optimized conditions (pH=3, 2 hours, adsorbent dose 0.8 g and room temperature). The removal efficiency of the real wastewater under optimal conditions was 82.1%.
Conclusion: Oxidized FA can be used for the removal of this pollutant from industry wastewater due to its high efficiency of removal in real wastewater, it is easy and inexpensive to prepare and could modify the sorbent.
Background: Continuous expansion of potable water pollution sources is one of the main concerns of water suppliers, therefore measures such as water safety plan (WSP), have been taken into account to control these sources of pollution. The aim of this study was to identify probable risks and threatening hazards to drinking water quality in Lighvan village along with assessment of bank filtration of the village.Methods: In the present study all risks and probable hazards were identified and ranked. For each of these cases, practical suggestions for removing or controlling them were given. To assess potable water quality in Lighvan village, sampling was done from different parts of the village and physicochemical parameters were measured. To assess the efficiency of bank filtration system of the village, independent t test was used to compare average values of parameters in river and treated water. Results: One of the probable sources of pollution in this study was domestic wastewater which threatens water quality. The results of this study show that bank filtration efficiency in water supply of the village is acceptable.Conclusion: Although Bank filtration imposes fewer expenses on governments, it provides suitable water for drinking and other uses. However, it should be noted that application of these systems should be done after a thorough study of water pollution level, types of water pollutants, soil properties of the area, soil percolation and system distance from pollutant sources.
Background: Co(II) constitutes a part of vitamin B12, hence, it is necessary for human health. However, at concentrations higher than the permissible limits, humans and animals suffer adverse chronic effects. It is necessary to reduce the concentration to a permissible level. In the present study, pre-purification and thermal modification of chicken’s feather increased their porosity and they were used to adsorb Co(II) ions from aqueous solutions.
Methods: Chicken feather was procured from a slaughter house, washed with detergent and dried at laboratory temperature. To increase the porosity and remove the organic pollutants attached to the feather, feathers were heated in the oven for 1 hour at 165°C. Some batch experiments were conducted to optimize the parameters affecting the adsorption process, such as solution pH, initial concentration of Co(II) and contact time, at a constant agitating speed and temperature.
Results: The pHzpc of chicken’s feather granules obtained was 5.3. The results showed that a time of 60 minutes, pH value of 9 and initial concentration of 10 mg/l were the optimum conditions for Co(II) removal by the adsorption process. Increasing the initial concentration of Co(II) from 10 to 50 decreased the removal efficiency from 52% to 26%. The pseudo-first order kinetic model provided the best correlation (R2 = 0.998) for adsorption of Co(II) on chicken’s feather granules.
Conclusion: The increase in electrostatic repulsion forces between positive charges of Co(II) ions decreased the removal efficiency at higher concentrations of Co(II) ions. The maximum efficiency of Co(II) adsorption was obtained at pH= 9, which is higher than the pHzpc of the adsorbent.
Background: Enterococci have emerged as a major cause of nosocomial infections and within this group, Enterococcus faecalis and Enterococcus faecium cause the majority of human and livestock enterococcal infections. In this article, we tried to determine antibiotics and metals resistance patterns of E. faecalis and E. faecium strains.
Methods: One hundred sixty different strains of E. faecalis and E. faecium were collected from livestock sewage and the human fecal waste during 15 months. Then bacterial antibiotics sensitivity tests were carried out using the Agar disc diffusion method.
Results: Generally, 100% of E. faecalis strains separated from human and livestock sources (i.e. sheep) showed penicillin (P)/ kanamycin (K)/ nitrofurantoin (N)/ loracarbef (L)/ Ciprofloxacin (Cc)/ ampicillin (AN)/ nalidixic acid (NA)/ sulfamethoxazole (S) antibiotics resistance patterns. In addition, 55% of isolated E. faecium showed P/S/AN/NA antibiotics resistance patterns. Each strain showed a resistance to at least two aminoglycoside antibiotics. However, E. faecalis strains from human and the livestock sources showed 94% and 100% of resistance to nitrofurantoin, respectively. The effects of different metal concentrations was evaluated in both strains. The agar dilution method was applied in this stage. Hg at 0.05 mmol/L of minimum inhibitory concentration (MIC) showed toxicity to both the human and livestock Enterococcus strains. Cadmium at 1 mmol/L and 0.5 mmol/L concentrations had the most toxicity to E. faecalis and E. faecium strains, respectively. Obviously, toxicity to bacteria is less than other metals. As a result, Zn/Ni/Cu/Co resistance pattern is suggested for both strains. Finally, antibiotics and heavy metals resistance patterns were monitored simultaneously.
Conclusion: Almost all E. faecalis strains isolated from humans and livestock showed antibiotics and heavy metals resistance patterns of P/K/L/Cc/S/AN/NA/Zn/Cu/Co simultaneously. Moreover, 55% of E. faecium strains showed similar antibiotics and heavy metals resistance patterns of P/S/AN/NA/Zn/Ni/Cu/Co.
Background: In recent times, the decreasing groundwater reserves due to over-consumption of water resources and the unprecedented reduction of precipitation, during the past 1 decades, have resulted in a change in the volume and quality of water with time. The aim of this study was to determine the spatial and temporal variations of hardness and total dissolved solids in drinking water resources of Ilam city, using the GIS system.
Methods: This cross-sectional study was carried out on 20 sources of drinking water in Ilam and the results of 5 years archived by the Water and Sewage Co were analyzed using geographic information system (GIS) software version 9.3, SPSS version 16 and one-way analysis of variance (ANOVA). The sampling and measurement were also performed in this study based on the Standard Method book.
Results: The ordinary kriging method and spherical model are the best interpolation methods for hardness and total dissolved solid, due to the normal distribution of data. The highest values of parameters in most cases are related to the western parts based on maps. The one-way ANOVA test showed that the average amount of total hardness (P = 0.68) and total dissolved solids (P = 0.6) in different seasons of the year are the same.
Conclusion: Overuse of groundwater due to illegal digging and permanent easy access to water, increased the salinity of water in the central sections of the studied area. Proper planning that allows the withdrawal of water from authorized underground aquifers or water supply from surface water or dams should be done to overcome this problem.