Sharif Digital Repository

In this study biological denitrification method by moving bed biofilm reactor is investigated. The main advantage of MBBR reactor is due to their capacity for high removal rates and low operational problems such as clogging. Two MBBRs in series with 3 liter volume each, were designed in experimental set up and used in this research. Nitrification reactor worked under aerobic conditions and denitrification reactor operated under anaerobic conditions. Methanol was used as carbon source in the reactors throughout the study. Fifty percent of each reactor volume was occupied with KMT1 packing. To finding the optimum nitrate loading rate, the concentration of ammonium and nitrate were changed from... 

Underground water is one of major resources of drinking water in Iran and thus, its quality (in terms of absence of pollutants) is a matter of great importance. The main goal of this research was to investigate the pollution concentration in underground water and soil in two regions: Dasht-e-naz in Sari and the fields near Sarkhoun gas refinery. The second goal was to determine the source and measure the distribution of the pollutants (in case of presence) and determine potential risks caused by them. The first step was to perform experimental tests in the two regions. In Sari's Dasht-e-naz region, a number of wells were chosen for sampling according to the direction of underground water... 

Within the past few years, soil and groundwater resources contamination by petroleum-based products has become of great concern in the environmental engineering literature as a serious environmental problem throughout the world. Amongst petroleum hydrocarbons, groundwater contamination by Non-Aqueous Phase Liquids (NAPLs) is one of the most important environmental problems. In order to effectively remediate contaminated sites, knowledge of the distribution of the NAPLs is essential. The success of the remedial design will be dependent on the ability to predict the subsurface distribution of the NAPLs. Release of these compounds from spills and leaky underground storage tanks into subsurface... 

Groundwater beneath the cities is becoming an important and valuable resource. Conjunctive use of surface and groundwater is likely to become increasingly more common as urban population grows by time. Therefore, one important requirement for urban water management planning is forecasting the groundwater level fluctuations. Unfortunately less experience and information is available to evaluate the fluctuations of groundwater level in urban environment compare to the natural systems, also different processes (sources) are involved in an urban water cycle, which all together make it more complicated to study. Similar to many other megacities, there is a serious lack of hydrogeological and... 

Ground water is one of major resources of drinking water in Iran and thus, its quality (in terms of absence of pollutants) is a matter of great importance. The main goal of this research was to investigate the pollution concentration in the Ground water and soil in the fields near South Pars Gas Complex Co. (SPGC). The second goal was to determined the source and measure the distribution of the pollutants (in case of presence) and determine potential risks caused by them. The first step was to perform experimental tests in the two regions. In SPGC region, a number of wells were chosen for sampling according to the direction of Ground water movement. All samples were taken using two EPA... 

Pump and treat is one of the oldest and mostly used methods in remediation of groundwater. Although this method has been criticized recently, it is still widely be used. The systems typically use one or more extraction and injection wells to hydraulically control the contamination plume. The purpose of studying a pump and treat system is to determine the appropriate location and discharge for the wells in the way that the contamination could be pumped out. In this study after reviewing some existing solutions for delineation the capture zone of single well a method to delineate the capture zone for arbitrary located wells is presented. This method can delineate a three dimensional capture... 

Incline in the population and civilization, development of agriculture, and expansion of industries, in addition to limitations on surface and groundwater resources necessitate the existence of correct and efficient planning of management and utilization of water resources. Prediction of behavioral models of changes in water resources systems, influenced by utilizing strategies, absolutely helps stakeholders for conservative development of these resources. System dynamics is an object oriented method that is based on system's feedback. Not only it gives real description of complex systems, but also it provides the ability to influence effectively in development of the model for the user. The... 

Petroleum based products are the major sources of energy for industry and daily life, With the development of social economy, the demands of the oil have increased dramatically. Petroleum hydrocarbons can cause environmental pollution during various stages of production, transportation, refining and use. Releases of petroleum products(e.g., gasoline, diesel, fuel oil) from aboveground and underground storage tanks or transport pipelines are the major causes of the environment pollution.The major constituents of petroleum hydrocarbons are biodegradable. Many soil microorganisms transform oil hydrocarbons into nontoxic compounds or mineralize them to inorganic compounds. In situ... 

Using a combination of groundwater and surface water, is defined as each project planned by combining these two sources which, in most cases, will achieve greater benefits than the non-integrated. The benefit is a set of privileges that technically, economically and environmentally justify the project. One of the prevalent and effective problems of fertile and flat plains of Khuzestan province, especially the Evan plain, is lack of proper drainage of agricultural land downstream of dams and irrigation networks which are covered by. In this plain also, according to statistics from Piezometers, the groundwater level is rising. At the first, the aim of this study is to study the current... 

In present research in-situ groundwater remediation by permeable reactive barriers is considered and the main goal is to find the optimal dimension of reactive walls and also to find the most efficient reactive media. Here, computer simulation is done via MODFLOW. Different barrier lengths, widths, depths and distances between trenches have been considered and contaminant removal percentage calculated in all situations. Based on the research achievements increasing the barrier length has led to reduction of contaminant removal percentage because flow gradient and flow density decrease by length increase. As the results show, contaminant removal percentage increases by width increase because... 

One of the subjects that have been title for many research proposals in recent years is application of Nano Zero Valent Iron (NZVI) particles in contaminant removal from groundwater sources. Despite many studies being done, field application of this particles in a practical scale is not widespread yet which is due to many challenges like rapid settlement of particles or their unclear behavior through field application. The main purpose of this thesis in the first place is to find a practical and productive method for stabilization of particles and enhancement of their transport properties. To reach this goal, application of a natural polymer like starch has been studied as a solution. To... 

Groundwater resources are considered as important resources of fresh water specifically in arid and semi-arid regions like Iran. Urmia Lake (UL) basin is one of these regions where groundwater resources play an important role in supplying water and due to inappropriate water resources management during the last two decades it has faced serious problems, like declination of water level in UL. Groundwater and surface water form an integrated system in the UL basin and have a mutual effect on each other. Hence, any improvement in exploitation of aquifers in that region could benefit UL water demand management. Appropriate water resources management in Miandoab plain which transfer almost 50... 

Groundwater resources in arid and semi-arid regions, which the most parts of them have not had enough surface water, is of great importance. Due to the paramount importance of these vital resources, many scholars have conducted various studies on groundwater contamination and, especially, on nitrate as the best indicator of groundwater contamination because of its ability to transport, its low absorption, and its durability in water. In this study, using qualitative methods, groundwater contamination of Mashhad aquifer was evaluated, and then in order to obtain better adjustment with urban areas, these methods were modified which resulted in better correlation with measured nitrat. Based on... 

In recent years, the reductive dehalogenation of the chlorinated hydrocarbons using nanoscale zerovalent iron (nZVI) represents a promising approach for underground remediation. Regarding commercialization of this technique, instability and unknown nature of nZVI particle are still challenging tasks that should be considered.
In the current work, Nanoscale zero-valent iron (nZVI) and palladized iron (Pd/Fe) bimetallic particles were synthesized and employed to react with chlorinated compound (PCE) in water to investigate its degradation behaviors. The results show that the reactant ratio, stabilizer amount and temperature are the main parameters with the considerable effect on PCE... 

The level of water at Lake Urmia has decreased dramatically in the last two decades. Lake-Urmia basin is one of the regions in which most of the consumption of water is based on groundwater resources. The annual withdrawal of groundwater in the Urmia Plain is about 468 MCM which is the highest rate of water extraction throughout the basin. In this research, interaction between surface and groundwater flow is simulated using MODFLOW and remote-sensing. METRIC algorithm is used for estimating the amount of recharge to groundwater. The model is calibrated in 24 months of 2008 and 2009. The results show that the main input to the aquifer is the return flow of agricultural lands and the main... 

Deformation and Settlement of the ground surface and stability of large underground space is the main concern in the excavation under urban area. In order to control settlement and increase stability, it is necessary to use pre-Supporting system prior to excavation. Concrete Arc Pre-supporting System (CAPS) is one of the most useful pre-supporting methods which is used in exchange station of line 3 and 4 of Mashhad subway. Line 3 and 4 are parallel in Shohada square and the groundwater level is above the whole station structure. To analyze deformation of the ground due to excavation stages, the station was modeled in 2D and 3D by Abaqus. In this study, to estimate ground Deformation, we need... 

In this paper we seek to find the contribution of groundwater in irrigation agriculture in Iran. We use nationwide panel data of agricultural production in the period of 1993-2013. The results show us differences in productivity of agricultural outputs due to availability of groundwater. Panel data allows us to control regional factors like soil fertility affecting the productivity. We are looking for the main contributors to groundwater usage. Population growth in demand side and groundwater availability in supply side seem to be the most important factors  

The goal of this research is to investigate the phenomenon of saltwater up-coning into pumping wells in fractured porous media. For this aim, two series of regular orthogonal fracture networks and different vertical and horizontal fracture apertures are simulated using an axisymmetric (2D vertical cross-section) model with a sharp interface approach. The effect of changing the pumping rate and the hydraulic conductivity has been examined to recognize other effective characteristics of the aquifer and pumping well on the saltwater up-coning. These simulations have been performed in COMSOL Multiphysics. The results indicate that the saltwater extent under the pumping well can be affected... 

Land subsidence is one of the consequences of groundwater withdrawal. This phenomenon can cause cracks in the surrounding structures, balance out the foundation of bridge piers, damage to roads, pipelines, etc. The main goal of this study is to provide a coupled flow-deformation model capable of simulation of land subsidence associated with groundwater extraction in unsaturated isotropic and true anisotropic aquifer systems, using the element-free Galerkin (EFG) method. Using this model and based on the geological features of an aquifer, we can easily forecast the hydraulic head change and land subsidence in different places and times during groundwater pumping. According to the current... 

Global climate change and anthropogenic impacts lead to alterations in the water cycle, water resource availability and the frequency and intensity of floods and droughts. As a result, developing effective techniques such as hydrological modeling is essential to monitor and predict water storage changes. However, inaccuracies and uncertainties in different aspects of modeling, due to simplification of meteorological physical processes, data limitations and inaccurate climate forcing data limit the reliability of hydrological models. Assimilation of new observations constrains the dynamics of the model based on uncertainties associated with model and data, which can introduce missing water...