فهرست مطالب mahdi asadi-aghbolaghi

Human civilizations have always depended on freshwater to form, develop and fulfillment of various needs. With increasing urbanization, not only has the need for freshwater not diminished, but also some new technologies and industries have increased water consumption, and the pollution of water sources has increased significantly. Since groundwater resources are far from surface pollution and have their natural remediation ability, protection and remediation have not been given sufficient and appropriate attention. This issue and the overexploitation of aquifers have resulted in the quantitative and qualitative balance of groundwater resources being unsustainable. These issues show that further research is needed on various aspects of groundwater remediation. By developing the equations for water movement in porous media and analyzing them, it is possible to simulate groundwater flow. In this study, the double-well pumping system has been investigated analytically as one of the effective methods for aquifer remediation. In this system, pumping wells provide a return to natural conditions by draining polluted water and preventing it from spreading in the aquifer. For this purpose, the equations of the groundwater potential function and the stream function were determined for two pumping wells near a permanent stream. In other words, the real part of the complex potential equation represents the potential function and its imaginary part specifies the stream function; using the image well theory, the effect of the stream was also applied in the problem relations. By determining the coordinates of the stagnation points, the capture zone of the multi-well system was delineated in various configurations and the amount of stream withdrawal was also calculated. The capture zone describes the behavior and capability of the multi-well system by indicating the capture domain of discharge wells for different distances and different pumping rates. Three configurations of the remediation system are presented for two types of critical pumping rates. Under these conditions, it is possible to control the capture zone without intercepting the stream boundary and creating gaps in the extraction region at different distances of the wells with certain pumping rates. At the first critical pumping rate, the capture zone of the double-well system is tangent to the permanent stream boundary, and at a pumping rate below this threshold, groundwater pollution does not reach the surface waters. At the second critical pumping rate, capture zones of two wells merge together. Indeed, in discharges less than this critical rate, there is a distance (gap) between capture zones of the wells and pollution can enter the surface water through this gap. Also, the distance between two wells was determined in the state that both types of critical pumping rate are equal. This case shows a state of capture zone whose boundary is tangent to the stream boundary, and the capture zones of two wells are merged together. In the mentioned state, the dimensionless distance between two pumping wells (the distance between the two wells divided by their distance from the stream boundary) and the dimensionless critical pumping rate are equal to 2×0.58 and 0.33, respectively.

Prediction of effluent quality parameters of wastewater treatment plant is essential in managing water resources, limitation of fresh water resources in the world, furthermore the ever-increasing population growth and the development of urbanization, have made the approach of urban wastewater reuse inevitable. In such a situation, the use of recycled water can be considered as one of the ways to overcome water shortage and prevent wastage of water resources. This research aimed to investigate the performance of Prediction of effluent quality parameters of wastewater treatment plant in using recycled water. On the other hand, due to the health hazards caused by the discharge of wastewater from wastewater treatment plants to water sources, achieving a precise design and correct management of wastewater treatment plants (WWTP: Wastewater Treatment Plant) is one of the important challenges of sustainable water resources management. 4 effective parameters including (BOD), (COD), (TSS) and (pH) of wastewater, were selected as input to the model, during a statistical period of 3 years (1397 to 1399). Also, 70% and 30% sizes were determined as the best sizes for training and testing stages in order to model BODeff and CODeff parameters. In this study, multi-Layer perceptron models (MLP), basic radial neural network models (RABF), as well as the integration of these models with several other algorithms, such as genetic algorithm (GA), particle swarm optimization algorithm (PSO) and sine cosine algorithm (SCA), were used in order to predict the quality parameters of wastewater treatment plant effluent.

The protection of groundwater resources against pollution is an important and essential issue. One of the effective methods in the treatment of aquifers is the utilization of the injection-extraction well pair system (hydraulic fence system). In this study, the remediation system of a pair of injection and extraction wells near a stream was analytically analyzed. The potential and stream functions were analyzed together with the capture and release zones of the wells in three configurations. The base flow rate (i.e. the minimum flow rate to initiate the circulation cell between the recharge and pumping wells) was calculated and analyzed in different modes. The critical flow rate (i.e. the allowable maximum flow rate for the extraction region of the pumping well without intercepting the stream) was also specified and interpreted in the configurations for the problem. In the first configuration and when the wells were located at the dimensionless distance of 2×0.4 from each other, the critical flow rate (QCR=1.07) was more than the base flow rate (QBS=0.22). In the second configuration, equality of base and critical flow rates causes a common stream line passed through the stagnation points of the recharge and pumping wells, while the stagnation point of the pumping well was tangential to the stream. In such a situation, the dimensionless value of the distance between the injection-extraction well pair and the dimensionless value of the critical flow rate (which in this case is also equal to the base flow rate) were achieved as 2×1.04 and 0.61, respectively. In the third configuration and when the dimensionless distance between the wells was equal to 2×1.2, the critical flow rate (QCR=0.59) was less than the base flow rate (QBS=0.70). According to the results, the flow rate was determined while the remediation system captured stream’s water and the conditions of entrance of the pollution into the stream from the aquifer were created. Also, the minimum flow rate was determined for the well pair system which can has full and gapless coverage against pollution.

The emphasis of this study was to study the effects of waves, prediction and estimation of sediment transport rate at different coastal forest cover densities. Experiments were performed on the effectiveness of a mangrove tree to reduce tsunami energy, by a simulated polyethylene artificial shrub structure. The cover has a rigid structure (including 2 cm trunk system and 25 cm height and 1 cm root) and structure (including branch

Disinfection is a process designed to disable pathogens, thereby preventing the transmission of waterborne diseases. An important aspect of chemical disinfection is the design of chlorine contact basins. Chlorine contact systems with sufficient time (contact time) disinfect the water for chemical reactions to inactivate pathogens. Design of chlorine contact basin or chlorine contact tanks is to maximize the phenomenon of Residence time through the flow of spiral of baffles through the basin or contact tank. Historically, chlorine contact tanks have been investigated by empirical relationships, physical model studies, or tracer studies after the construction of a contact tank. Construction of laboratory samples and tracer studies are time consuming and costly. In recent years, computational fluid dynamics models have been used to investigate the flow and processes of solute transport in contact tanks, which is the best way to design contact tanks before construction. In this study, a 3D simulation of the CT-1 contact tank is performed using Multiphysics 5.3a software. Also, several 3D simulations in the CT-1 contact tank, in which the effect of the baffle orientation in a longitudinal direction with three different channel widths was performed, it was concluded that the narrow channel with a ratio of Winlet /Wch=0.68 (channel to inlet width ratio) and Lbo / Wch ratio (baffle opening length to Channel width ratio) equal to 1 has the highest baffle factor and the least amount of Morill index and therefore optimal hydraulic.

In this research, the hydraulic characteristics of flow through circular culverts and over broad crested weir are experimentally investigated for 12 models. Stage discharge rating curve was presented for each model. The results show that for a specific head, the discharge of combined structure is greater than the summation of discharge of weir and culvert. Also, the discharge coefficient for the combined structure is varying from 0.25 to 0.73 and for the weir is varying from 0.25 to 0.63 and for the culvert is varying from 0.33 to 0.77. The dimensionless parameter H/D (head to diameter) has the greater influence on discharge coefficient. In addition, regression equations are presented for estimation of discharge coefficient.

Side weirs are used to control the amount of discharge in main channels and rivers. One of the types of side weirs are labyrinth Semi-elliptical side weir and Due to the greater crest length in a certain range of transverse, have more the discharge capacity than rectangular weirs. For these reasons in this study, flow around a semi-elliptical and rectangular labyrinth side weir was simulated with three-dimensional modeling finite volumeand compared with laboratory measurment. The effects of increasing the flow in the main channel and the height and length semi-elliptical side weirs on flow pattern in subcritical flow conditions were studied and finally the experimental results were compared with the simulated results for rectangular side weir. Numerical results indicated that the model can predict the the flow pattern on the side weir with high accuracy .The results of the simulation showed that the effects of secondary flows in both weirs were reduced by increasing the height of the rectangular and semi-elliptical side weirs and then, the water surface profile would be more uniform and the error rate decreas. The maximum of velocity in semi-elliptical side weir is induced in the near of free surface at the end of the side weir and the discharge coefficient of semi-elliptical side weir is more than rectangular side weir.In this study an equation was offered in order to determine De-Marchi discharge coefficient for semi-elliptical side weir.This coefficient in subcritical flow conditions depends on the Froude number in the main channel, the ratio of upstream depth to the height of side weir, the ratio of upstream depth to the length of side weir and the ratio of small ellipse radius to large ellipse radius.

Tide induced head fluctuation has been considered by many researchers in coastal areas. In this paper, a numerical solution has been developed for an inhomogeneous multi-layered aquifer. This aquifer system comprises an unconfined aquifer on the top, a semi-confined aquifer at the bottom, and an aquitard between them. This coastal aquifer is bounded by coast in longitudinal direction; the coastal boundaries are parallel to each other. The results showed that the amplitude of unconfined aquifer head increases with increase of leakage, however, the amplitude of head fluctuation decreases in the semi-confined aquifer. In addition, the results of analytical solution, the head fluctuation in unconfined aquifer decreases with increase of dimensionless storage coefficient, however, it is almost constant in confined aquifer. Also, increase of dimensionless transmissivity increases the groundwater head fluctuation in both aquifers. Temporal head fluctuation illustrated that time lag has not significant changes, and is greater for semi-confined aquifer with respected to confined aquifer. Comparison between numerical and analytical solutions showed that there is little difference between.