Iranian Journal of

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Background and Objectives:Nowadays vermicompost production of food wastes is posed as one of appropriate methods to food wastes. disposal, its production used in agriculture and gardening. Moreover this process has some by products beside useful fertilizer that one of them is the worms. we can use them in variety of products specially in production of poultry and fish food. So determination of optimal condition for operating vermicompost production process of food wastes and worms. growth in these wastes is important. The aim of this study was determination of optimal temperature and moisture range for process progression in vermicompost production of food wastes.
Materials and Methods: In this study we used Eisenia foetida species. Process performed in pots with 15 cm (h) and 12 cm (d) and in a mouth period of time. Three ranges of temperature including 5-15, 15-25, 25-35 oC and three ranges of moisture including 55-65%, 65-75%, 75-85% were applied in this study.
Results: Multivariate analysis was used for analyze of results and it showed that influence of temperature and moisture on C:N ratio is significant in vermicomposting process (p <0.05).
Conclusion: The results showed that the range of temperature 15-25 oC is more appropriate for operating of process. Due to these study.s results with increasing or reduction of ambient temperature, like summer and winter, conservation of moisture around the range of 65-75 %, is effective in better performance of the process. According to this study.s results, it seems that the temperature of 15- 25 oC and moisture of 65-75% are better conditions for worm.s growth.

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Background and Objectives: Recycling is one of the best alternatives in solid wastes management.  Recycling has few benefits from the viewpoint of economics and environmental. Paper and cardboard are the valuable recyclable materials in solid wastes. The rate of paper recycling is 35% in world. The major production source of paper and cardboard wastes is private and governmental offices and organizations. To be informed about paper production is very important in the solid wastes recycling.Thus, the aim of this study was to determine production rate of paper and cardboard waste and also to determine paper recycling potential in the 20 head offices of Mazandaran province.
Materials and Methods: This study was conducted in the 20 head offices of at province center. The  offices were selected by chance. This study was conducted four months in 2006. paper waste was separated after suspension of work. Collected material weighed on the sensitive scales. Separation and measuring was done for a week per month.
Results: The results showed that more than 2 tons of paper waste was produced in the twenty offices.  The maximum and minimum of paper production was in education and recycling organization, respectively. The maximum and minimum of production rate was 2.08 and 0.192 kg per capita in month that was in the education and Jihad-e-Agriculture organization, respectively. Also the maximum and minimum of paper waste was produced at first work day of week (Saturday) and last work day of week (Thursday), respectively. However, it was not significantly (P >0.05). Paperrecycling operation and marketing was done in an office.
Conclusion: Findings of this study indicated that office solid waste management needs more notice  in Iran. And also calculations showed that paper recycling is economical.

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Backgrounds and Objectives: Due to importance of ionizing radiation on human health, many studies have been performed to measure the background gamma radiation all around the world as well as some cities in lran. According to this fact that everybody spends almost 80% of his time in indoor areas, this study was carried out to measure the amount of background gamma radiation in indoor areas in Zanjan city located in northwest of Iran to determine the annual effective dose of the city residents.
Materials and Methods: To determine the dose rate of background gamma radiation in indoors, 30 dwelling (in the main geographical directions and in the downtown areas) were selected. All of them were one floor and iron roofed. A Geiger-Muller detector (RDS-110) calibrated by Cs-137 was used in each livings room of each dwellings that performed in one meter far from the earth. In 30 minute 30 values was recorded. The mean value was considered as indoor gamma dose rate in each dwelling.
Results: The mean value of dose rate in Zanajn indoor areas due to gamma background radiation was determined 146±25 nGy/h. According to the results and findings in our previous study about gamma background radiation in outdoor areas in Zanjan, the annual effective dose was determined and 0.87 mSv for Zanjan city residents.
Conclusion: The annual effective dose of Zanjan city residents due to the gamma background radiation is 0.87 mSv that in comparison with UNSCEAR-2000 report is higher than the mean value for the world (0.48 mSv).

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Backgrounds and Objectives:Water contamination with arsenic has been recognized as a serious problem and its epidemiological problems to human health have been reported. The objective of this study was to explore the possibility modified wheat straw using sodium bicarbonate for removing arsenic from aqueous solution.
Materials and Methods: Adsorption process was accomplished in a laboratory-scale batch with emphasis on the effect of various parameters such as pH, contact time, arsenic concentration and adsorbent dosage on adsorption efficiency. In order to understand the adsorption process, sorption kinetics and equilibrium isotherms were also determined.
Results: It was found that adsorption of the arsenic was influenced by several parameters such as arsenic initial concentration, adsorbent dosage and solution pH. Maximum absorption efficiency was achieved at pH 7. As expected the amount of arsenic adsorbed on wheat straw incresed as its concentration went up. Among the models tested, namely the Langmuir, Freundlich, and Dubinin Radushkevich isotherms, the adsorption equilibrium for arsenic was best described by the Langmuir and Freundlich models. It was also found that adsorption of arsenic by wheat straw followed pseudo second-order kinetics. Mean free energy of adsorption (15.8 kJ mol-1) indicates that adsorption of arsenic by wheat straw might follow a chemisorption mechanism. Desorption studies show that arsenic ions are strongly bounded with the adsorbent and exhibit low desorption.
Conclusion: It is concluded that that adsorption by modified wheat straw is an efficient and reliable method for arsenic removal from liquid solutions.

 

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MicrosoftInternetExplorer4 Background and Objectives: The increasing demand for drinking water has led scientists to the use of saline waters, but existing desalinating processes are very expensive. carbon aerogel is a type of organic aerogel that is suitable for desalination owing to its unique porous structure. Low potential of fouling and deposits, very low wastewater production, electrostatic regeneration of aerogels and, in turn, no need to acid consumption, and lower power consumption are some of this technology benefits.
Materials and Method: In this experimental- analytical study, the purpose was survey of saline and brackish water desalination using carbon aerogel technology and its comparison with electrolysis.The community studied was synthetic salt water samples, using of TDS and EC indicators. The minimum synthetic samples were 243. In this regard, after polymerization of Resorsinol and Formaldehyde compounds under ambient pressure conditions and then its pyrolysis, we fabricated plates of carbon aerogel.
Result: With manufacturing in the pilot-scale, the effect of different parameters, including input salt concentration, current, water flow, distance of between electrodes and pH, on NaCl sorption amount of carbon aerogel electrodes were studied. Generally, adsorption amount increased with increasing of current and NaCl concentration and decreased with increasing of distance electrodes, flow and pH. 
Results: Fabricating reactor at pilot-scale, we studied the effect of different parameters, including input salt concentration, current, water flow, intra-distance of electrodes, and pH on the NaCl sorption using carbon aerogel electrodes. Generally, adsorption capacity increased with increasing of current and NaCl concentration in the inlet flow, and it decreased with increasing intra-distance of electrodes, flow, and pH.
Conclusion: Under the most optimal conditions, our results showed that the NaCl adsorption rate on carbon aerogel electrodes was about 1.43×10^-4 M NaCl per g of carbon aerogels indicating its cost-effectiveness.

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Background and Objectives: Electro-Fenton process has been widely applied for dye removal from aqueous solution lately. Fenton's reagent is formed in the electrolysis medium through the simultaneous electrochemical reduction of O₂ and Fe³⁺ to H₂O₂ and Fe²⁺ respectively on the cathode surface. In this paper, COD reduction potential and decolorization of real textile wastewater were evaluated by electrochemically generated Fenton reagent process. This wastewater mainly contains non-biodegradable acidic dyes, which are highly resistant against conventional oxidizing agents.
Materials and Methods: Electro-Fenton process was carried out in an open and undivided cell in order to evaluate the removal of color and COD from real textile wastewater using graphite felt (cathode) and Pt plate (anode) at room temperature. The effects of current density, flow rate of air, electrolysis time, initial pH, and ferrous ion concentration were investigated for real textile wastewater.
Results: The results showed that the optimal experimental conditions obtained in electrochemical studies were as follows: current density=4.8 mA cm-2, pH=3, flow rate of air=1.5L/min, Fe²⁺=3mM and reaction time=160 min. Under these conditions, COD removal and decolorization achieved were 63% and 77.2% respectively.
Conclusion: According to the results achieved, electro-Fenton process can be used as a pretreatment for degradation of colored wastewater and refractory pollutants. Moreover, this feasible technology improves biodegradability of the textile wastewater.

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Background and objectives: Formaldehyde is one of the compounds widely used in various industries hence, its discharge into the effluent is unavoidable. Exposure to formaldehyde has a significant health effects. To prevent these issues, treatment of wastewater containing formaldehyde is necessary. The purpose of this study was to determine the performance of aerobic sequencing batch reactor (SBR) in removing formaldehyde from wastewater. Methods: We used a SBR having a total volume of 6.15 liters and an effective volume of 4 liters. The formaldehyde and COD removal efficiency of SBR was evaluated by applying loading rate of 0.031 to 0.156 kgCOD/m3.h. Four cycles of 6, 8, 10, and 12 hours were considered to investigate retention time effect onto the reactor efficiency. Results: Acclimation of microorganism with formaldehyde was achieved after about 30 days. We found that a retention time lower than an hour is not enough for achieving an acceptable efficiency. The maximum removal efficiency (90.52% for COD and 95.32% for formaldehyde) was observed at organic loading rate of 0.031 kg COD/m3.h and 12 hour retention time. The removal efficiency decreased to 46.44% for COD and 69.12%, for formaldehyde with increasing the organic loading rate to 0.156 kg COD/m3.h. The maximum concentration of MLSS was measured 2863 mg / L at organic loading rate of 0.091 kg COD/m3.h. Conclusion: The results showed that SBR could be applied as a practical, effective, and reliable technology for treatment of wastewater containing formaldehyde.

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Background and Objectives: Water is essential for sustaining life & adequate safe supplies must be accessible to the public. Nowadays, people prefer to purchase bottled water for reasons including taste, convenience, following fashion, and its safety and sanitary conditions. According to the WHO guideline, it is of great importance to control the bottled water because of keeping it for longer period of time and at higher temperature in comparison with the water of distribution networks, reusing containers and bottles without adequate washing and disinfecting, and more growth of microorganisms having less important in the terms of health. The aim of this study was to investigate the microbial and physicochemical quality of bottled water in the stores of Qazvin City and to compare the aforesaid features with national standards and to check the quality with the bottles label.
 Materials and Methods: In this cross-sectional study, 51 samples of 11 bottled water brands with different production date were obtained. The features were studied in accordance with Standard Methods. Then, the data were analyzed by T-Test and one way ANOVA analysis using SPSS software. Eventually, the results were compared with the national standards, the WHO guidelines, and the product labels.
Results: Results showed lack of microbial contamination of the samples. Physically and chemically, all the parameters measured were below the national standards level. Study of conformity of the variables to the label indicated that mostly there was a significant difference between the values measured and the values listed on the product labels. Conclusion: Although the concentration of microbial, physical and chemical features of samples were in the extent of national standards, there was a meaningful difference between labels and measured values so that the average concentration of TDS, TH, SO4-2, Ca2+, Mg2+ and Na+ would be more than the label values and the average of the other parameters was lower than the label values.

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Background and objectives: Perchloroethylene (PCE) is categorized as contaminant of concern because of its adverse health effects and persistence in drinking water resources. Permeable reactive barrier with zero valent iron (ZVI-PRB) is a passive zone in which chlorinated ethenes are degraded in situ through the chemical reduction mechanism. The objective of the present investigation was optimization and modelling of ZVI-PRB technology for the elimination of PCE from the aqueous environment using response surface methodology. Materials and methods: In order to simulate ZVI-PRB, a column filled with silica sand and ZVI was used. effects of three variables including pH, column height or barrier thickness and flow on reductive dechlorination efficiency were assessed. Design of experiment, modelling, and data analysis were carried out using response surface method. Results: The dechlorination efficiency was about 93% under optimum conditions (pH=5, 26 cm column height and 2 mL/min flow rate). The ascending trend of pH along the column revealed that the reductive condition was dominant within the column. The R² value of 0.98 also indicated good fitness of the experimental results and model predictions. Conclusion: Based on the results, ZVI-PRB technology has high efficiency in dechlorination of PCE. Likewise, regarding to no need of energy consumption, abundance of iron, no production of harmful by-products and cost-effectiveness, ZVI-PRB is propounded as a stable, green, and environmental friendly technology in groundwater remediation.

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