فصلنامه پژوهش در بهداشت محیط
سال یکم شماره 1 (بهار 1394)

Increased use of nanoparticles in industries leads to entering hazardous substances to environment. Nanoparticle toxicity due to release of toxic substances into the environment is a concern for communities. One of the common nanoparticles ingredients are zinc oxide. In this study toxicity of the solution containing the Reactive Red 120 dye after Nano-catalytic process UV/ ZnO using biological test Daphnia magna was studied. this is a fundamental – practical study، which done on laboratory scale. Toxicity assay tests were carried out using Daphnia magna a bio-indicator. Then results of toxicity tests using SPSS software were analyzed and Lc50were determined. Results showed that the Lc50 value ​​at 24،48،72،96 hr is 73. 16، 55. 93، 41. 32، 30. 45 mg/l and the toxicity unit values are 1. 36، 1. 78، 2. 42، and 3. 28، respectively. the results generally indicated that toxicity increased in process and over time and showed that Reactive Red 120 after UV/ ZnO process was toxic to Daphnia magna.

Textile industry is one of the largest consumers of dyes. Approximately 75% of global dye production is used for dyeing textile, leather, and paper products. Dyes due to their complex structure are mostly stable, toxic, carcinogenic, mutagenic, and resistant to biodegradation; they also can cause allergies and skin conditions in humans.This study aimed to evaluate the efficacies of multi‐walled carbon nanotubes and palm ash for dye removal from textile wastewater in Baluch region of Iranshahr in Iran. This experimental study was performed on textile wastewater with a dye concentration of 20 mg/L in 2013. The efficacy of multi‐walled carbon nanotubes and palm ash for dye removal at different concentrations, durations (30, 60, 90, 120, and 150 minutes), and pH ranges (3, 5.7, 9, and 11) was investigated. Dye concentration in different samples was measured, using a spectrophotometer at a wavelength of 525 nm. The rates of dye removal using multi‐walled carbon nanotubes at pHs of 3, 5, 7, 9, and 11, dye concentration of 20 mg/L, and adsorbent concentration of 0.05 g/L were 85.5%, 93.4%, 88.4%, 81.3%, and 75.3%, respectively during 180 minutes. The corresponding values for palm ash were 88%, 92.8%, 96%, 92.2%, and 88.7%, respectively. The rates of dye absorption were 1710, 1868, 1769, 1626, and 1506 mg/g for multi‐walled carbon nanotubes and 1763, 1857, 1921, 1844, and 1775 mg/g for palm ash, respectively. According to Langmuir isotherm model, adsorption isotherms were R2=0.876 and R2=0.980 for carbon nanotubes and palm ash, respectively. The maximum removal of chemical oxygen demand (COD) in multi‐walled carbon nanotubes was obtained at pH=5, adsorbent concentration of 0.05, and contact time of 180 min (73.4%). For palm ash, maximum removal was achieved at pH=7, adsorbent concentration of 0.05, and contact time of 180 min (70.6%). Dye removal from textile wastewater can be promoted by increasing reaction time. Dye and COD removal by multi‐walled carbon nanotubes and palm ash was desirable. In fact, in multi‐walled carbon nanotubes, efficacy was desirable at acidic pHs, while in palm ash, neutral pH was considered desirable. Therefore, use of palm ash for the removal of environmental pollutants can be cost‐effective, given its high abundance.

With the increasing trend of imports and exports in the country, the number of transport vehicles is also growing at the customs gates across the world. This causes the wastewater disinfection gates to increase in number at the borders of a country. Du to a cationic detergent called Benzalkonium chloride, the wastewater produced in these places is not biologically treatable. Therefore, advanced oxidation methods are considered as a viable option for treating the wastewater. In aspect-oriented programming (AOP), catalytic ozonation with activated carbon is regarded as an efficient method of disinfection. The present study aimed to determine the optimal conditions of using activated carbon produced from agricultural waste and activated with NH4CL as a heterogeneous catalyst with Ozone. In this study, the chemical quality of wastewater was evaluated at the disinfection customs gate of Lotf Abad Using single and catalytic ozonation by NH4Cl-induced activated carbon obtained from agricultural waste as the base material, COD removal was performed in a 200cc continuous reactor. The studied variables were pH, catalyst concentration and the reaction time. In the catalytic ozonation, single absorption and the synergistic effect of the catalysts were also investigated. According to the results of the present study, with the ozone dose of 1 mg/min of alkaline pH in 30 minutes, single ozonation was able to remove only 39.7% of COD while catalytic ozonation with 0.1 g/L of carbon catalyst concentration in the same condition removed 66.8% of COD creating a 13.6% of synergistic effect as well. Activated carbon with NH4CL could noticeably increase the oxidation with ozone. Thus, it could be used as a catalyst in the ozonation reactor in order to remove COD from wastewater.

the role of swimming pools as a useful and interesting sport is obvious to everyone, which its curable aspect has been considered these days. On the other hand, we should not reject the possible threats of this sport. So, the purpose of this research is to consider the quality of swimming pools, Whirl pool and cool water basin in Tehran. in this descriptive- analytic inquiry which has been done in first six months of 1392, in 12, 13, 14 and 15 areas of Tehran municipality and within two parts, studied 27 active lidded swimming pools. At first stage, it has been got samples from all these pools and at the next stage, it has been got renewed samples after presenting suitable ways and instruction to the liable of swimming pools which have been polluted at first stage. All the stages of sampling, transferring to the lab and analyzing of samples from the aspects of remained free color quantity, PH, microbial contamination has done based on standard methods of water and sewer tests. the results show the amount of remained free color at National standard limit of minimum 0 and maximum 4(1-3mg/L) in 48% of samples. 76/1% had standard pH(7.2-8) and also Heterotrophic bacteria of all samples were in a good situation. this study showed the most microbial contamination part was whirl pools and cool water basins in which the amount of remained free color was not on standard extent. Also, in renewed getting samples from pools which were contaminated at first stage of tests, all samples were lack of microbial contamination after considering necessary preparation by liable of swimming pools and giving structures by environmental hygiene inspectors of east hygiene center.

Background an Natural organic matters because of production of disinfection by products such as trihalomethanes, which are often carcinogenic disinfection, are of particular importance. Carbon nanotubes due to large surface area, and many other applications, are effective adsorbents for the removal of natural organic matter. The present study aimed to investigate the removal of natural organic compounds from aqueous solution by single-walled carbon nanotubes and kinetics and equilibrium adsorption process. in present study, single wall carbon nanotubes used for removal of natural organic matters from aqueous solution. Different variables such as pH of zero point of charge, pH and different concentration of natural organic matters were investigated. pH survey show that with decreasing pH adsorption capacity increased also pH of zero charge was 6.7. Adsorption capacity of single wall carbon nanotubes for initial concentration of natural organic matters of 10, 5 and 3 mg/L were 66.24, 40.63 and 29.77, respectively. Single-walled carbon nanotubes due to features such as high surface area have great potential for the removal of natural organic matter from aqueous solution

Paper, pulp and cardboard manufacturing industries discharge large amounts of waste which contain a variety of pollutants and paints. These wastes are believed to generate the most environmentally hazardous industrial wastewaters. Biological procedures alone may not suffice the treatment of such wastes due to having a high BOD5/COD ratio. On the other hand, applying costly chemical approaches to remove all these pollutants in a short time often results in the production of large quantities of sludge. Therefore, these industries are obliged to combine both these methods in order to optimize wastewater treatment. In this experimental study, the sample wastewater was provided from the discharge channel of Pazh cardboard factory located in Tous Industrial Zone of Mashhad, Iran. The wastewater samples were collected from this factory by composite sampling. Coagulation of these samples was accomplished by clay soil as the single coagulant. The optimum pH of the treatment was determined by Jar tests in various pHs (from 4 to 9). Afterwards, the optimum concentration of the coagulant was also verified at the optimum pH of 8 by Jar tests. The optimum dosage and pH of treatment by clay soil wasdetermined to be 75 g/L and 8, respectively. Under optimized conditions, the removal efficiency of COD, BOD5 and TSS was calculated as 47%, 26% and 57%, respectively. In addition, the pH adjustment at 8 resulted in a 60% reduction of clay consumption. According to the results of this study, the coagulation of cardboard wastes by clay soil could be a suitable pretreatment method. This particular material makes it possible to improve the quality of wastewater in subsequent bio treatments in a much less costly way compared to other conventional coagulants or adsorbents. It was also observed that the ratio of BOD5/COD reduced from 4.5 to about 3. Although the clay dosage required for the wastewater treatment is relatively high, this approach could stillbe recommended for the pretreatment of this type of wastewater as well as the wastes produced by similar industries mainly because the overall cost of this treatment is insignificant.

Mushroom cultivation has recently been developing in Iran with a production level of 90 tons per year.Approximately 5 kg of waste is generated by producing one kilogram of button mushrooms.These wastes could be refined by using vermicompost technology converting them into valuable organic fertilizers to replace chemical fertilizers as a way to achieve sustainability. This study aimed to convert button mushroom production wastes into manure and investigate the chemical properties and quality of this fertilizer. Such wastes as rotten mushrooms, spent mushroom compost (SMC) and peat are generated during the cultivation process of button mushrooms in large quantities. In this study, SMC was vermicomposted in an optimized process of treatment with wood chips, rotten mushrooms, carrot scum and leaves. Quantitative and qualitative indicators and their changes were investigated during six weeks. The obtained results were compared with the National Standards of Vermicompost (No. 13724) and the overall quality was determined in the final product. We used the SPSS software and Pearson’s correlation coefficient at the significance level of 0.05 in order to examine the correlation between the inorganic materials and changes in other parameters. In addition, Linear Regression Analysis was used to determine the relationship between the studied variables. The results of this study indicated that the Total Organic Carbon (TOC), potassium and total nitrogen in all the treatments increased with time. However, pH and electrical conductivity (EC) levels declined during the vermicomposting process. Furthermore, a significant increase was observed in the C/N ratio in all the treatments by the end of the six‐week period. Therefore, all the fertilizers were classified as Grade one. According to the results of this study, vermicompost process could enhance the indicators of organic fertilizers derived from vermicompost beds. Thus, this method could be suitable for the waste management of button mushroom production in order to achieve a sustainable agriculture.

Industrial developments and urban sprawl have led to the production of huge proportions of wastewater. Wastewater is potentially harmful for humans and it has remarkably adverse effects on the natural environment. With regard to the importance of preserving health and protecting the natural resources against pollution, this study aimed to evaluate the performance of wastewater stabilization ponds in the wastewater treatment plant of Olang, Mashhad. This cross‐sectional study examined the raw wastewater and effluent of Olang treatment plant from 2011 to 2012. Weekly sampling as well as BOD5, COD and TSS tests were conducted according to the standard methods. The collected data were analyzed by SPSS software, one‐way ANOVA and one‐sample t‐test at a significance level of 0.05. In 2011, the average concentration of BOD5, COD and TSS in the effluent was 75±30.67, 145±19.46 and 86±13.28 mg/L, respectively. In addition, their treatment efficacy was 79.79±10.77%,82.53±4.57% and 77.17±3.92%, respectively. The figures were respectively 83±14.08, 146±23.72 and 109±14.73 mg/L and 82.7±5.11%, 82.82±3.82% and 78.46±3.93% in 2012. The effluent could be used for agricultural irrigation since its features are compatible with the standard parameters.