Introduction: H2S production in sewage collection networks creates many problems, including corrosion of concrete pipes, effects on human health and unpleasant smells. ). Although the sewerage is designed in such a way that the air flows and the H2S gas production does More
Introduction: H2S production in sewage collection networks creates many problems, including corrosion of concrete pipes, effects on human health and unpleasant smells. ). Although the sewerage is designed in such a way that the air flows and the H2S gas production does not occur due to the anaerobic process, but sometimes due to improper design, increase in flow rate, pipe clogging or fracture, the H2S gas disperses around the manholes. Monitoring the sewage network by determining the amount of H2S gas can help network repair in a timely manner. Due to the high cost of advanced monitor systems. The continuous management of sewage networks in developing countries requires the development of cheap and economical methods.
Materials and Methods: In this research, 150 manholes were selected in Ahwaz city in Iran. Paper tapes impregnated with lead acetate were prepared. They were placed in different areas around and inside the manholes. After collecting samples, they were classified into seven grades according to the amount of obscuration created in the indicators. At the same points as the samples were taken, the amount of H2S gas was measured by the gas meter. And gas concentration limits were determined for each.
Results and Discussion: The results showed that lead acetate paper indicator detected a concentration of H2S from zero to 35ppm. The best positioning of the indicators was within the manholes, and the best contact time was set at 24 hours.
Conclusion: It is appropriate to use the results of the ranking of indicators in a situation where it is not possible to use advanced sensors to monitor sewage networks.
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Visible steam emitting from the cooling tower and H 2 S smell are obvious environmental manifestations of a geothermal facilit More
Visible steam emitting from the cooling tower and H 2 S smell are obvious environmental manifestations of a geothermal facility. They are usually coupled with concerns about exposure to the high toxicity of mercury and arsenic along with radon radiation. They have been, to a large extent, responsible for the perception that air quality is significantly affected by geothermal activities. In reality, air quality is affected by geothermal facilities a little, especially as compared to many other industries or fossil-fuel power plants. If the quality of air is considered in the construction and utilization of geothermal installations, worries about air quality will be removed. The key to success in air quality programs is the early collection of data, plant operational scenarios, educational programs, etc.The present study aims at predicting dispersion pattern of one of the main gases of Sabalan geothermal power plants to find a solution for its probable negative effects.
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The genus Taverniera from Fabaceae family is one of the most valuable plant species compatible with desert areas, which is very important in terms of forage production, soil conservation, and medicinal properties. The current research was carried out to investigate the More
The genus Taverniera from Fabaceae family is one of the most valuable plant species compatible with desert areas, which is very important in terms of forage production, soil conservation, and medicinal properties. The current research was carried out to investigate the effect of different treatments on seed dormancy breaking and germination stimulation of taverniera cuneifolia. Dormancy breaking treatments included H2SO4 (50% and 75% for 5 and 10 min.), scarification with sandpaper (for 1 min.), KNO3 (0.1% and 0.2% for 24 and 48 h.), hot water (70 and 90 ℃, each for 15 min.) and hydropriming (for 36 h.) with three replications. Results revealed that H2SO4 (75% for 5 min.) led to the highest germination speed and seed vigor index and the lowest mean germination time. Also, maximum germination percentage (78%) was observed under this treatment. Scarification with sandpaper also exhibited considerable effect on the germination percentage (76%). Thus, H2SO4 (75% for 5 min.) and scarification with sandpaper would be suggested as the most efficient treatments to break seed dormancy of Taverniera cuneifolia.
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