فصلنامه سلامت و محیط زیست
سال ششم شماره 3 (پیاپی 21، پاییز 1392)

In this study, treatability of wastewater from a laundry unit was investigated by applying electrocoagulation method in which two pairs of aluminum and iron electrodes were utilized. Electrocoagulation is a noble treatment method suitable for different kinds of wastewater which has been given a considerable attentions by researchers recently. Applying direct current to two or several suitable metallic electrode in a batch reactor containing effluent would result in flocks of metal hydroxide. We studied the effect of different operational parameters such as pH, electrodes distance, intensity of electrical current, and type of electrodes on the treatment efficiencies. Aluminum electrodes showed better effects on the treatment efficiencies in nitrate and COD removal. Maximum phosphate removal (99.93%)took place at pH=7 using Al electrodes. Whereas, in the case of iron electrode, maximum nitrate and COD removal efficiencies were about 97.60 and 80% at pH=9 and pH=6 respectively. Operational cost analysis showed that the corresponding costs of Al application as an electrode is different from that of iron electrode application. Although application of both iron and aluminum electrodes lead to obtaining considerable removal phosphate, nitrate and COD, iron electrodes could result in reasonable removals to meet Environmental Standards with lower operational costs.

Rivers are the most important resources supplying drinking, agricultural, and industrial water demand. Their quality fluctuates frequently due to crossing from different regions and beds as well as their direct relationship with their peripheral environments. Thus, it is essential to be considered the surveying and predicating changes in the water qualitative parameters in a river. In this study, in order to estimate some of the qualitative parameters (Total dissolved solids, electrical conductivity and sodium absorption rate) for Tehran Jajroud and Kermanshah Gharasu rivers, we used wavelet-artificial neural network (W-ANN) hybrid model during a statistical period of 24 years. We compared W-ANN model with ANN model in order to evaluate its capability in detecting signals and separating error signals for estimating water quality parameters of the abovementioned rivers. The evaluation of both models was performed by the statistical criteria including correlation coefficient, the Nash-Sutcliffe model efficiency coefficient (NS), the root mean square error (RMSE) and the mean absolute error (MAE). The results showed that the optimized W-ANN with correlation coefficient of 0.9 has high capability to estimate SAR parameter in the stations studied. Moreover, we found that W-ANN had less error and higher accuracy in the case of EC and TDS parameters rather than ANN model. W-ANN proved high efficiency in forecasting of the water quality parameters of rivers, therefore, it can be used for decision making and assurance of monitoring results and optimizing the monitoring costs.

Many of non-respiratory and respiratory disorders are associated with bioaerosols in indoor and outdoor air. The best conditions for bioaerosols life are high humidity and moderate temperatures, which exist usually in indoor spaces such as the prisons, where density of individual is high. Pathogen spreading centers cause the prisoners health at risk of disease outbreaks through airborne and breathing, sneezing, and coughing. Therefore, the aim of this research work was to measure concentration of particulate matters and also to identify and determine bacteria existing in the prisoners breathing air at high-density areas in one of the prisons and their relationship with each other. we conducted this research during summer and winter of 2012. We used TSI apparatus for collecting particles (PM2.5 and PM10). Blood agar and EMB agar media were applied to measure bacteria in indoor air (bedchambers and clinical admission wards) of the prison. According to NIOSH 0800 method, High volume pump with 28.3 L/min flow and a Single-stage Anderson Impactor were used for sampling. The time of measuring for each plate was 2.5 min. Finally, the data achieved were analyzed using SPSS after counting and detecting bacterial colonies grown and determining its density (CFU/m³) for two consecutive seasons of summer and winter. The tests analyzed by SPSS were ANOVA, Post hoc, correlation, and Pearson correlation tests. Amounts of particulate matter in bedchambers were exceeded than 24-hour EPA limits, while it was less than the limits in clinical admission wards. Gram-positive and gram-negative bacteria were found in three bedchambers (50% of the bedchambers); however, gram-positive bacteria were cultivated only in three bedchambers. The maximum bacterial contamination was measured at the main Lobby of the prison and bedchamber II and the minimum value was observed in admitted patient and TB patient wards. Results showed that there is no significant relationship between the particulate matters and the bacterial density during neither summer nor winter, but there is a strong and direct relationship between the prisoners population density, ventilation systems, and bacterial density n indoor air of the studied prison. Based on the results, the maximum contamination load and exceeded concentration was observed in public sections and bedchambers. This findings were attributed to the daily entry of new prisoners, high population density in prison, presence of ill prisoners, prisoners with hidden respiratory disease showing no symptoms yet, old building, climatic conditions of the region, low efficiency of ventilation systems, and influx of particulates. To filter and purify prison indoor air, it is crucial to take serious action plans such as reducing criminal population density, sanitary and engineering measures.

Modelling and specifying mathematical equations to predict and estimate a bioprocess is one of the important applications of bioengineering. Objective of this study was to identify proper and exact equations to describe various changes in biodegradation of heavy fuel oil through investigating kinetic models and third parametric equation of Ch. To submit an exact and perfect enough statement, two different experimental conditions were used in which isolated indigenous bacteria from environment were employed. Experiments were carried out during ten days and microbial growth, mazut concentration, pH, and electric potential curves were drawn. Fitting data onto kinetic models and Ch equation resulted accuracy and their constants. We found that kinetic models were not capable to present an accurate and appropriate statement under different conditions. On the other hand, Ch equation by extending very accurate equations could satisfyingly illustrate mazut, pH, and electric potential changes based on time and microbial growth. Ch equation by reason of using two variables for computation of third variable and correctly selecting variables could describe various changes in mazut biodegradation under different conditions via mathematical statements. Moreover, it is possible that this equation can be used to study other various phenomena in future.

Water complexes including Jacuzzi are among the most popular water recreation centers that noncompliance with health standards can lead to increased microbial growth in water and thus the risk of infection. This study aimed at comprehensive study of jacuzzis water in Yazd city and comparing the results with national and international standards. This was a descriptive - analytical study that statistical society included all Jacuzzis of Yazd city. Sampling of jacuzzis was performed every two weakes for 3 months (Summer 2011). We tested the water samples for parameters such as temperature, pH, amount of residual chlorine, turbidity, alkalinity, hardness, the population of heterotrophic bacteria, Staphylococcus aureus, Pseudomonas aeruginosa, fecal streptococci, and fecal coliforms accordance with standard methods. The SPSS software and ANOVA, T-test statistical tests, and/or Kruskal-Wallis, and Mann-Whitney were used for description of data and the obtained results were analyzed by comparing with standards. we found that the mean of residual free and combined chlorine was equal to 0.628 and 0.337 mg/l respectively. The alkalinityand hardness were 141.928 and 275 mg/lCaCo3 respectively. Mean of pH, turbidity and temperature were equal to 7.88, 0.457 NTU and 38.121˙C respectively.Moreover, the mean population of fecal streptococci bacteria, heterotrophic bacteria, Staphylococcus aureus, Pseudomonas aeruginosa, and fecal coliforms were 20465.7, 120.77, 209.91 and 7131.4 in 100 ml respectively. Statistical analysis of data showed that there is a direct relationship between water turbidity and pH (Pvalue=0.018); however, population of heterotraphic bacteria and residual free chlorine had indirectl relationship (Pvalue= 0.026). According to the results achieved, the parameters of heterotrophic bacteria population and alkalinity had the least compliance with the standard indicating the need for continuous monitoring of physical, chemical, and microbial parameters of Jacuzzi water and control of the number and density of people using Jacuzzi and continuous monitoring of Jacuzzi water filtration and chlorination process performance.

The aim of the study was to design and implement integrated solid wastes management pattern in Shahroud industrial area, to evaluate the results, and to determine possible performance problems. This cross - sectional study was carried out for 4 years in Shahroud industrial area and the implementation process included: 1. qualitative and quantitative analysis of all solid wastes generated in the area, 2. determining the current state of solid waste management in the area and identifying programs conducted, 3. designing and implementation of integrated management pattern including design and implementation of training programs, laws, penalties and incentives, and illustrating and implementing programs for all factories, and 4. monitoring the implementation process and determining the results. Annually, 1,728 tons of solid waste is generated in the area including 1603 tons of industrial waste and 125 tons of municipal wastes. By implementing this pattern, two separated systems of collection and recycling of domestic and industrial waste were launched in this area. Moreover, consistent with the goals, the amount of solid waste generated and disposed in 2011 was 51.5 and 28.6 kg per 100 million Rials production respectively. In addition, 42 and 40% of the industrial waste and paper were recycled. Results showed that implementation of this pattern, i.e. running source separation, training programs, capacity building, providing technical services, completing chain of industries and strengthening the cooperation between industrial estate management and industrial units could greatly reduce the waste management problems.

Chlorination is the most common method of water disinfection. Chlorine reaction with natural organic compounds nor removed completely during treatment process would result in forming disinfection byproducts. Followed by trihalomethanes، Haloaceticacides are the second main byproducts of chlorination in water. The research works conducted in Iran have assessed trihalomethanes. Hence، this is the first time we are reporting haloacetic acids in Iran. Materials and We collected samples from surface water resources and treated water in Tehran for six consecutive months (first half، 2010). We measured temperature، pH، UV adsorption at 254 nm and TOC in each surface water sample and analyzed pH، residual chlorine، and haloacetic acids in the treated water samples. We found that TOC in surface water resources is 3. 6-4. 42 and 1. 78-2. 71 mg/l in spring and summer respectively. Moreover، haloacetic acids concentration was found to be 41. 7-55. 56 and 34. 83-43. 73 μg/l in spring and summer respectively. Our results revealed that concentration of NOM، TOC، and HAAs was more in spring than summer. In addition، concentration of HAAs was depended up on NOM and TOC. Considering maximum permeable concentration of HAAs (60 μg/l) by EPA، it can be claimed that concentration of HAAs was less than the maximum permissible level in all of the samples. However، the immanency of the monitored values to the standard values can be a warning for concerned authorities in water industry.

In arid and semi-arid regions، wastewater reuse has become an important element in agriculture. However، irrigation with this resource can be either beneficial or harmful، depending on the wastewater characteristics. The aim of this research was to investigate the soil bacterial and crops quality irrigated with treated wastewater. This research was conducted on a maize field near the wastewater treatment plant in Shahr-e-kord in summer،2011. Plots were arranged in a randomized complete block design in 3 replications and 2 treatments، well water (W1) with fertilizer and effluent (W2). At the end of growth season، soil samples were collected from depth of 0-5 and 5-15 cm and plant samples consisting of old and new leaves and seeds were collected for bacteriological analysis. According to bacteriological analysis، total number of positive lactose bacteria، total and fecal coliforms in depth of 0-5 cm was 42% more than depth of 5-15 cm. In the case of old leaves، total number of coliform and fecal coliform was 88 and 40 MPN/100 mL respectively. Moreover، for new leaves، it was 38 and 2 MPN/100 ml respectively. According the results، number of indicator bacteria in soil is decreased (about 35%) by passing time.

Increasing waste tiers production has made the recycling of this solid waste a critical issue in the world. On the other hand، it seems contamination of groundwater to the petroleum pollutant like gasoline is a great threat to the health of societies in developing countries. The main objective of this study was gasoline removal from aquatic environment by waste tire derived activated carbon. In this study for preparation of activated carbon from waste tires، KOH was used for chemical activation process. We used argon gas to prevent precursor oxidation. We applied N2 gas and BET isotherm for characterization of the prepared activated carbon texture. Isothermal and kinetic models were used for defining gasoline adsorption characteristic to adsorbent، and thermodynamic studies were used to determine the effect of temperature. Characterization results revealed that SBET and VTOTAL were 111. 702m2/g and 0. 124cc/g respectively. Langmuir and pseudo-second order models were the best isotherm and kinetic models for prediction of the adsorbent behaviors to adsorb gasoline. The Gibbs free energy changes were negative at all temperatures applied. Produced activated carbon has desired surface area and adsorptive capacity for gasoline adsorption in aquatic environments and it seems preparation activated carbon from waste tiers is cheap، effective and environment friendly.

In this study، the removal of dye blue reactive-171 by combination of advanced oxidation processes UV/H2O2 and SBAR has been investigated. The efficiency of chemical and biological system was first investigated separately. In chemical system، the kind، power، initial dye concentration and hydrogen parasitize and in biological system، hydraulic detention time، aeration rate، initial dye concentration and the percent removal of dye and COD were investigated. In order to investigate the hybrid system، after determination of the optimum conditions and the capabilities of each system، the removed chemical system effluent from residual hydroxide peroxide، was entered into the biological reactor. In the chemicals process، 100 ppm dye using 150 Watt-UV-C lamp and 0. 1 mM hydrogen peroxide at pH= 9 was completely removed in 25 minutes. COD removal was 86. 7 percent at the end of the experiment (135 min). Biological system with adsorption mechanism has shown 44 percent dye removal with initial COD of 50 mg/L that indicated the system inability in biodegradation and breaking down of the dye molecule. In comparison to separate chemical and biological processes، hybrid system has shown better dye removal efficiency. The results indicated that in addition to the complete dye removal achievement، 81% of COD in the first hybrid system and 52% of COD in the second hybrid system was removed، respectively. According to the results، because of complexity of dye structure، biological system was not able to remove the dye as efficient as hybrid system of advanced oxidation processes UV/H2O2 with SBAR.

Metal pollution has always been a major cause of contamination of environment and is considered as a major concern for food health. Worldwide، sturgeons are an important source of food and income. In this study، the human health risk due to consumption of caviar and muscle of Persian sturgeon (Acipenser persicus) were evaluated by measuring the concentrations of cadmium، nickel، vanadium and zinc in caviar and muscle samples. A total number of 24 samples of Persian sturgeon were collected from two important sturgeon fishery zones in Guilan and Mazandaran Provinces and were stored at −20°C until chemical analysis. About one gram of each sample dried was added to 10 ml of concentrated (65%) supra-pure HNO3 (Merck، Darmstadt، Germany) in a Teflon PTFE tube and then it was incubated for 1 h at 40 °C in a hot block digester، followed by heating at 140 °C for 3 h. The samples digested were diluted to a measured volume using double deionized water. Samples were filtered through Whatman No. 1 filter paper، and the filtrate was stored until metal determination. Mean Cd، Ni، V and Zn concentrations in muscle tissues were 0. 005 ± 0. 002، 0. 06 ± 0. 03، 0. 13 ± 0. 04 and 7. 49 ± 3. 07 µg/g wet weight basis respectively. The mean Cd، Ni، V and Zn concentrations in caviar samples were 0. 007 ± 0. 006، 0. 09 ± 0. 07، 0. 12 ± 0. 15 and 21. 23 ± 5. 75 µg/g wet weight basis respectively. Conculation: The mean concentrations of Zn، Cd and V in caviar and muscle samples were less than the permissible limits proposed by the United Kingdom''s Ministry of Agriculture، Fisheries and Food (MAFF 2000) and World Health Organization (W. H. O.). The guidelines for Cd، V and Zn are 0. 2، 0. 5 and 50 µg/g wet weight respectively. Therefore، the measured concentrations for these particular metals are below the published guidelines، and the levels would appear not to constitute any threat to the human population that may consume sturgeon or caviar obtained from these study locations.