Showing 5 results for Rezvani
Hossein Karimi , Ali Asghar Ebrahimi , Mahrokh Jalili, Mohammad Rezvani, Mehdi Mokhtari ,
Volume 1, Issue 1 (June 2016)
Abstract
Introduction: The present study aimed to investigate the microbial quality of the produced vermicomposts and compare them with the existing standards.
Materials and Methods: This experimental study was conducted as a pilot-scale one in the laboratory school. Some perishable domestic wastewater mixed in a reactor, including food waste, vegetables and fruits, cow manure and sludge from wastewater treatment plant. Tests to determine the microbial quality of the product were carried out at an early stage during the process of production and on the final product. These tests included determining the probable number of fecal coliform bacteria and parasite eggs.
Results: According to the results, a significant decrease was observed in the number of fecal coliforms in sludge manure and domestic waste, as the number of fecal coliforms reduced from 5000000 (MPN / g) in the raw sample to 1500 (MPN / g), eight weeks after the outset. Moreover, according to the obtained results, the mixture of manure, sludge, and domestic waste had some parasite eggs (20 number /gr) in the raw samples. This amount was fully removed by the process of vermicomposting during the third week.
Conclusion: Findings revealed that the earthworms have a high capability to reduce the pathogens without increasing in temperature, however, in order to standardize the number of coliforms (compost class A), the vermicomposting of the mixture of cow manure, domestic waste, and sludge of wastewater treatment plant is not appropriate.
Mehdi Mokhtari, Mohammad Rezvani, Hossein Karimi, Atefeh Karimi, Zeinab Abbasszadeh, Roya Malekahmadi,
Volume 1, Issue 3 (December 2016)
Abstract
Introduction: Organic fertilizers are beneficial to maintain and improve structure of the soil nutrients; however, in case of presence of pathogenic microbial agents and pathogens inside them, it will result in health problems and disease transmission. Therefore, present study aimed to determine microbial quality of produced vermicomposts in Yazd city.
Materials and Methods: This study was a descriptive-analytical work where
10 % of vermicomposts production centers which were using cow manure were randomly selected in Yazd city and sampling was conducted in spring. In doing so, the desired microbial indices were measured and ultimately compared to the standard A of Iranian compost. Three samples were prepared from each center and in each sampling; 50 g of sample was picked. Finally, total number of taken samples was 30. The tests included determination of the probable number of fecal coliform bacteria and parasite eggs.
Results: According to the results of present study, the mean fecal coliform and parasite eggs for all centers were 1272 in confidence interval of 95 % (441-2102) and 0.73 in confidence interval of 95 % (0.32-1.13), respectively. Therefore, the mean fecal coliform and parasite eggs in derived vermicomposts were in class A standards range of Iranian compost.
Conclusion: Production of vermicomposts by animal fertilizers in Yazd city not only decreases these wastes but also gives rise to manufacture a strategic and valuable product which is in range of determined standards and is suitable for soil improvement and fertility.
Hossien Karimi, Mohammad Rezvani, Morteza Mohammadzadeh, Yaser Eshaghi, Mehdi Mokhtari,
Volume 1, Issue 3 (December 2016)
Abstract
Introduction: The presence of pathogenic microbial agents and pathogens in organic fertilizers causes health problems and disease transmission. The aim of this study was to evaluate the efficiency of vermicomposting process in improve the microbial quality of the compost produced.
Materials and Methods: This experimental study was conducted as a pilot-scale one, in the laboratory of school of Health. In order to produce vermicompost, some perishable domestic waste were mixed whit sludge of wastewater treatment plant in a reactor. Tests to determine the microbial quality of the product were carried out at an early stage, during the process of production, and on the final product. The worms used for the production of vermicompost were Eiseniafotida worms.
Results: According to the results of this study, a significant decrease was observed in the number of fecal coliforms in Sludge- domestic waste; as the number of fecal coliforms reduced from 7500000 (MPN/g), in the raw sample, to 1500 (MPN/g), eight weeks after the outset. Removal efficiency of fecal coliforms was 99.98 percent. Moreover, according to the obtained results, the mixture of Sludge and domestic waste had some parasite eggs (22 number/gr) in the raw samples. This amount was fully removed by the process of vermicomposting, during the forth week.
Conclusion: The results showed that earthworms are a great ability to remove pathogens but to reach the standard set in mixed microbial treatment sludge - waste can not be sure.
Davarkhah Rabbani, Amir Hossein Mahvi, Maryam Shaterian, Reyhaneh Hesamifard, Mohammad Rezvani Ghalhari, Morteza Kabiri, Gholamreza Mostafaii,
Volume 7, Issue 1 (March 2022)
Abstract
Introduction: Accessibility to safe drinking water is an important human health issue, so water reuse and water resources management are critical in arid parts of developing regions. This study aimed to investigate the use of a combined simple designed solar geyser/photocell for drinking water disinfection.
Materials and Methods: In this study, a solar geyser with a simple design was combined with a solar cell and its efficiency on the disinfection of contaminated water was investigated. This study was carried out with artificially polluted tap water by a solar geyser joined with a solar photovoltaic cell. The heated water (55°C) was kept for 2 hours using a solenoid valve. The pilot plant was operated and monitored for one year. The volume of the collected effluent was measured every 24 h. The most probably number (MPN) of total coliforms and fecal coliforms in 100 mL of 24-hour composed samples were measured.
Results: The mean volume of disinfected water production was calculated as 2095.74 ± 270.28 mL/day. The strongest correlation was found between disinfected water and the maximum daily ambient air temperature with a linear model (R2 = 0.9937). The results showed that by increasing the sunny time, the volume of water outlet increased. Therefore, sunny time and UV radiation have direct effect on volume of disinfected water.
Conclusion: The simple designed solar geyser for drinking water disinfection was efficient and recommended for tropical areas, emergency conditions, and farms for agricultural activities.
Ali Asghar Ebrahimi, Mohammad Hassan Ehrampoush, Arezo Rezaie, Shahriar Forghani , Hossein Karimi, Mohammad Rezvani, Zahra Soltanian Zadeh, Mahrokh Jalili ,
Volume 7, Issue 4 (December 2022)
Abstract
Introduction: Wastewater contains a large number of pathogenic and non-pathogenic microorganisms that can become bioaerosols during the treatment processes in different units of the treatment plant, and pose a risk to workers and nearby residents. In this study, the release of bioaerosols from a wastewater treatment plant of Morche Khort Industrial Town was investigated.
Materials and Methods: Sampling was actively performed according to EPA standard, in two seasons of spring and summer in 2018-2019, by an environmental sampling pump with a flow rate of 15 l/min and a single-stage impactor. The data were analyzed by SPSS software version 2020.
Results: The study results showed that the mean number of bacteria in the aeration tank was significantly higher than other points. The mean number of fungi in the aeration pond with 144 CFU/m3 had the highest concentration, and no fungal bioaerosol was observed 500 m downstream. Regarding the emission of H2S, CH4, and VOC gases, the anaerobic tank had the highest emission of these gases.
Conclusion: Wastewater treatment plants (WWTPs) with activated sludge treatment technology and an aeration system can lead to an increase in the concentration of bacterial and fungal aerosols around the units and in surrounding areas.
