Papers by Seyed Fazlollah Saghravani
DESALINATION AND WATER TREATMENT
The improvement of wastewater treatment plants is an environmental and economic priority. The hig... more The improvement of wastewater treatment plants is an environmental and economic priority. The highest energy consumption in wastewater treatment plants relates to aeration units with the current technologies. Microorganisms can use air micro-nanobubbles (AMNBs) for biological activity due to AMNB's high oxygen transfer rate, high stability in the aeration reactor, and increased contact surface. This study investigated the effect of aeration with AMNB on hydraulic retention time (HRT), energy consumption, chemical oxygen demand (COD), and nitrogen removal efficiency in the biological treatment of raw municipal wastewater without pretreatment for an extended time during cold and hot seasons. Suspended growth treatment and attached growth mode were studied by installing an active bio-curtain (ABC) as an improvement solution. In the presence of AMNB and ABC, effective microorganisms significantly increased ten times as conventional activated sludges (CAS). Micro-nanobubble aeration helped the oxygen transfer and accelerated the aerobic layer formation, which took advantage of partial nitrification and denitrification for total nitrogen removal and resulted in total nitrogen removal by 99%. In comparison, 78% and 97% of COD removal in suspended and attached growth modes were achieved in the warm seasons at the optimum HRT of 9 h. In the cold seasons, with a decrease of about 5%, the COD removal yields 73% and 90% in the identical HRT (9 h), respectively. The aeration energy consumption in this study to eliminate the definite ratio of organic loads shows a reduction of about 40% compared to CAS. Excess sludge reduction has also been achieved by up to 70%. In conclusion, this research shows the potential and possibility of practical exploitation of the AMNB aeration and ABC to treat municipal wastewater.
International. Journal of Mining & Geo-Engineering, 2016
The quality of concrete is highly dependent on the characteristics of its aggregate, such as the ... more The quality of concrete is highly dependent on the characteristics of its aggregate, such as the size, minerals, and their chemical properties. Even a small amount of impurities, such as hydrated sulfates, chlorine (salt), and acidic pH of the rock material, can adversely affect the quality of the concrete. Thus, many national codes and standards are developed for testing, selecting, and employing the rock materials in concrete. For instance, Iranian standards 446, 449, 1702, 4978, 4984, 7174, and 86721 are currently serving this purpose. In the present research, a new real-time system was developed in order to replace the customary chemical analysis and size distribution tests. 20 samples were taken from two mines, selected by the Building Material Committee of Semnan Province, in order to determine the dissolved chlorine and sulfate, pH, density as well as size distribution. The new system is constituted of hydraulic jacks and a reservoir, designed to take samples from the conveye...
The purpose of the research was to determine vertical accuracy of RTK-GPS in comparing with autom... more The purpose of the research was to determine vertical accuracy of RTK-GPS in comparing with automatic level surveying procedure as has been applied in the vicinity of the University Putra Malaysia campus. A comparison of the differences between the two methods indicates 95% confidence accuracy. The results obtained by this experiment indicated an accuracy of 0-10 centimeters in the measurement of elevation by RTK-GPS system. The result of the present work also indicated that the RTK-GPS system might be very useful in surveying work as carried out by topographers, engineers, and surveyors etc.
Sains Malaysiana
Estimation and forecast of groundwater recharge and capacity of aquifer are essential issues in w... more Estimation and forecast of groundwater recharge and capacity of aquifer are essential issues in water resources investigation. In the current research, groundwater recharge, recharge coefficient and effective rainfall were determined through a case study using empirical methods applicable to the tropical zones. The related climatological data between January 2000 and December 2010 were collected in Selangor, Malaysia. The results showed that groundwater recharge was 326.39 mm per year, effective precipitation was 1807.97 mm per year and recharge coefficient was 18% for the study area. In summary, the precipitation converted to recharge, surface runoff and evapotranspiration are 12, 32 and 56% of rainfall, respectively. Correlation between climatic parameters and groundwater recharge showed positive and negative relationships. The highest correlation was found between precipitation and recharge. Linear multiple regressions between recharge and measured climatologic data proved signif...
Journal of Computer Science, 2010
Problem statement: In three recent decays, computer software's are used for assessing and predict... more Problem statement: In three recent decays, computer software's are used for assessing and predicting of what happened and what will happen for surface and subsurface water. These supplementary tools are calculating and presenting potential recharge of contamination to estimate and assess important issue in hydrogeology such as amount of contamination in drinking water. There is a source of contamination in study area that was approved by some experiments in laboratory. In present study, movement of contamination horizontally and vertically simulated. Approach: Visual MODFLOW used to determine movement of groundwater and fate of contamination (phosphorus) by two different types of computers. Results: The results showed that both computers were able to run the software without critical problem. Also it was found that vertical migration is mainly responsible to migration of contamination. Conclusion: In conclusion, the software performance can be skilful and accomplished. It is able to solve a wide range of research problems with low rate of the errors.
American Journal of Environmental Sciences, 2009
Problem statement: Evapotranspiration (ET) has crucial role in agricultural activity, water manag... more Problem statement: Evapotranspiration (ET) has crucial role in agricultural activity, water management and hydraulic engineering. Recently many forms of the equation have been applied for estimating daily and monthly evapotranspiration around the world. Approach: In this study, the daily and monthly ET was estimated by Penman, Penman-Monteith (P&M) and Hargreaves equation to evaluate general relationships for estimating monthly and daily values of these 3 methods and also effect of different parameters such as Humidity and wind speed on fluctuation of ET. Results: The results showed that maximum and minimum values were belonging to Hargreaves and P&M models, respectively. Conclusion: Statistical analysis showed significant difference among the three methods and coefficient variant for daily and monthly analysis was 18.49 and 7.17 respectively. However, the difference between mean value of P&M and Hargreaves, that has the most different, is 1 mm year −1 .
DESALINATION AND WATER TREATMENT
This study aimed to remove sulfate from water solution through electrocoagulation, using multiple... more This study aimed to remove sulfate from water solution through electrocoagulation, using multiple electrodes in a continuous flow system. Moreover, the effect of important parameters, including scenarios for voltages applying to electrodes, flow rate, primary sulfate concentration, and pH on the sulfate removal process was evaluated. The experimental reactor was a rectangular box of 20 × 10 × 6, all in cm. The electrodes were plates of grade 1050 aluminum. The highest sulfate removal was 87% that occurred at a voltage of 30 V and 10 mL/min of flow rate (retention time = 135 min) at pH = 5.5, when the initial concentration of sulfate was 500 mg/L. The highest sulfate removal rate in non-uniform voltage configuration was observed in the arrangement of 10, 20, and 30 V (upstream, middle, and downstream, respectively) during 135 min for 10 mL/min flow rate. On the other hand, the economic assessment revealed that the lowest amount of electrical energy consumed for removal of one mg/g of sulfate occurs at a 10 V uniform voltage among the electrodes. The results showed that the electrocoagulation technique could successfully be applied to continuous flow systems to remove sulfate from aquatic environments.
DESALINATION AND WATER TREATMENT
This study aimed to remove sulfate from water solution through electrocoagulation, using multiple... more This study aimed to remove sulfate from water solution through electrocoagulation, using multiple electrodes in a continuous flow system. Moreover, the effect of important parameters, including scenarios for voltages applying to electrodes, flow rate, primary sulfate concentration, and pH on the sulfate removal process was evaluated. The experimental reactor was a rectangular box of 20 × 10 × 6, all in cm. The electrodes were plates of grade 1050 aluminum. The highest sulfate removal was 87% that occurred at a voltage of 30 V and 10 mL/min of flow rate (retention time = 135 min) at pH = 5.5, when the initial concentration of sulfate was 500 mg/L. The highest sulfate removal rate in non-uniform voltage configuration was observed in the arrangement of 10, 20, and 30 V (upstream, middle, and downstream, respectively) during 135 min for 10 mL/min flow rate. On the other hand, the economic assessment revealed that the lowest amount of electrical energy consumed for removal of one mg/g of sulfate occurs at a 10 V uniform voltage among the electrodes. The results showed that the electrocoagulation technique could successfully be applied to continuous flow systems to remove sulfate from aquatic environments.
Environmental Earth Sciences, 2014
Environmental Earth Sciences, 2015
ABSTRACT A practical and reliable approach was applied to investigate the groundwater dynamics an... more ABSTRACT A practical and reliable approach was applied to investigate the groundwater dynamics and obtain natural direct recharge based on the time series of water table fluctuation in moderately flat coastal area with a shallow water table and tropical rainforest weather. Drainage rate was about 0.034 m/day in the study area as estimated by falling groundwater table in period of no rainfall and specific yield values ranged between 0.11 and 0.23 by calculating depth-dependent specific yield based on soil water storage for layering soils. The method was applied to the monthly data of shallow aquifer at eight field sites in north Kelantan river catchment in the period of 1991–2011. The cross-correlation and partial cross-correlation reveal the acceptable correlation between the water table fluctuation and the rainfall data assuming the time lag from precipitation to water table response is negligible due to shallow water table. Recharge rates vary with the field sites and mainly depend on soil type and rainfall rather than surface geology. Although computer simulation (with MRCR code) was implemented with limited data (two series), still results are just slightly greater than the field data which indicated the method successfully employed and can be applied in areas with similar conditions in future.
Progress in Computational Fluid Dynamics, An International Journal, 2012
Journal of Hydraulic Engineering, 2010
ABSTRACT Counter flowing jets are effective devices for mixing and dilution of effluents injected... more ABSTRACT Counter flowing jets are effective devices for mixing and dilution of effluents injected into a stream. In the present study, the penetration length of a counter flowing free round jet was experimentally investigated. Jet nozzles with different diameters were used to form a jet located at the center of a closed conduit with a square cross section. Based on the measurement of the axial velocity on the jet axis, penetration lengths were determined. Under certain circumstances where confinement effects are absent, penetration lengths vary linearly with the ratio of the jet velocity to the main flow velocity. This study also provides a criterion for the range of velocity ratios for which this linearity is valid, and explains the disagreement in the existing literature on the determination of critical velocity ratios.
Canadian Journal of Civil Engineering, 2000
ABSTRACT A simple procedure to compute the length of gradually varied flow profiles is presented.... more ABSTRACT A simple procedure to compute the length of gradually varied flow profiles is presented. It is based on the direct integration of the dynamic equation for gradually varied flow, which forms the bases for existing methods of computing flow profiles. In these methods, a long reach for which the profile length is needed gets divided into several subsections, to ensure that the hydraulic exponents do not vary very much in the subsections. Since the proposed analytical method does not use the hydraulic exponent in its development, the flow profiles can be computed in one step and one can still get accurate results. The results of the profile computations based on existing methods are compared with the corresponding results of the present method. The results find direct application in hydraulic engineering practice, where flow profile lengths are needed for design purposes.
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Papers by Seyed Fazlollah Saghravani