Survey on hydrogen sulfide and ammonia emissions in the air around of the stabilization ponds Mineral gases producing odors in wastewater treatment

Abstract: (344 Views) Background and aims: Odors are one of the problems of water and wastewater treatment, especially in the vicinity of residential areas. Hydrogen sulfide and ammonia, mineral compounds in waste water treatment plants are odorous. These gases have unfavoraitable effects on humans and the environment. Methods: This Cross-sectional study was conducted in the Faculty of Health, Qazvin University of Medical Sciences. After field visits around the plant, the number of 12 sampling stations was determined. Sampling stations are selected in four geographical directions with regard to permanent trade winds that are zero, two and four kilo meters from the plant to Residential settlements. Sampling was performed in the morning and evening during the four seasons and 192 samples were provided. Results: Results showed that the concentration of ammonia and hydrogen sulfide gas was more in warm seasons significantly and more odor caused (P=0.011, P=0.004) and the maximum emission is in the summertime. According to the results, the highest concentration of these gases was in the evening during the day. Conclusion: According to the results, the concentration of hydrogen sulfide and ammonia gases in all the seasons except winter is within the threshold. Concentration of hydrogen sulfide in the summer and ammonia concentrations in all the seasons were higher than US. EPA standards and World Health Organization guidelines

Comparative Study of Bottled Water Microbial and Physicochemical Quality with National Standards and its label ( A Case Study in Qazvin City, Iran)

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

Response Surface Methodology to Optimize Wastewater Treatment in Carpet Industries by Potassium Ferrate

One of the chemical oxidation method for water and wastewater treatment is to use potassium ferrate. The aim of this study was to optimize the potassium ferrate consumption for wastewater treatment in carpet industries using central composite design and response surface methodology. The samples of this experimental study were collected from a carpet factory monthly and during two seasons. Measuring of the studied parameters were carried out based on the standard reference method for experiments in water and wastewater. To determine the optimized conditions for removing COD, color, turbidity and TSS by potassium ferrate, the central composite design and response surface methodology were used. The results showed that two independent variables of pH and potassium ferrate concentration and their interaction had a significant effect on removing COD, turbidity, color and TSS variables. The optimum condition for removal of these four pollutants were 160mg/l for consumption dosage of potassium ferrate and 4.5 for pH. In such condition the removal percentage of COD, turbidity, color and TSS were 86%, 85%, 84% and 83% respectively. In addition, the results indicated that the quadratic model has a good fitting to the experimental data. Potassium ferrate is recommended as an effective compound for reducing COD, color, turbidity and TSS from wastewater produced in textile industries especially in carpet industries. This process can be applied as a preliminary treatment and in cases where biological treatment is the main treatment, it could be used as a supplementary treatment