Sharif Digital Repository

The best method for stabilizing sludge is anaerobic digestion, In addition to reducing the amount of volatile solids; it produces biogas, which can be considered as a sustainable energy source for wastewater treatment plants. However, the most important factor limiting the process of digestion is the sludge hydrolysis, the best way to increase the speed of hydrolysis is to pre-treatment the sludge before entering the digester; One of the most effective pretreatment methods is pre-treatment by ozone gas, This gas, which is highly unstable, quickly reacts with the wall of the bacterial cell and oxidizes it due to its high oxidizing properties And accelerates the process of sludge hydrolysis.... 

In parallel to the growing of population in Tehran metropolitan, air pollution in this city has become to a major problem. From which high concentration of pollutants have adverse effects on public health, accurate estimating and forecasting of concentrations for several days ahead, can provide the possibility to implement the management measures to reduce hazard and risks. Among the air pollution models, application of statistic models based on neural network in comparison to the traditional deterministic models are easier and less costly. In most studies, static models use a classical single MLP to predict one step ahead. For this purpose ANN models are required to estimate next value of... 

Every year, air pollution is causing immense harm to humans and the environment. To cause Air pollution, several factors are involved. Among these are the sources of emissions such as factories, power plants and Cars, meteorological factors such as temperature and wind speed and geographical conditions such as altitude, postal and looming around the area, land slope and soil type region. The aim of this study is to identify factors that affect the ozone concentration in Tehran, which could help identifying other secondary pollutants. For this purpose, a combination tailored to the geography of Tehran using CMAQ-WRF-SMOKE-made programs. This model includes four intervals each of which lasting... 

In this thesis the hourly concentration of different gaseous air pollutants in Tehran is modeled using Land Use Regression (LUR) and Artificial Neural Network, separately. Both models are provided with the same set of input data; the first step is to find these data. Since traffic affects air pollution, information about traffic conditions is one of the main inputs in air pollution modeling. Therefore, to obtain traffic information, in this thesis, first a novel method is developed to extract and analyze Google Maps traffic data. In this method, image processing is used along with the Geographic Information System (GIS) to count the number of pixels of different traffic colors for each road... 

In this study, leaching of Sarcheshmeh Reverberatory Furnace Dust was investigated in the H2SO4-O3 media. Response surface methodology based on central composite face-centered design (RSM-CCF), was applied to optimize the operating parameters. The optimum conditions to obtain the main goal of maximum copper and minimum iron dissolution from dust were identified to be temperature of 30˚C, leaching time of 3hr, initial pH of 0.5, pulp density of 20% and ozone flow rate of 1g/h. The copper and iron concentrations of leaching solution were found to be 27.11 and 0.89983 g/L under the optimum conditions, respectively. The results showed that selective copper extraction from the dust could be... 

Membrane bioreactors (MBRs) are a combination of activated sludg and mebrane technology. MBRs have been widely used as an advanced process for urban and industrial wastewater-treatment in recent years. Membrane fouling is the main issue that limits their performance and therefor, many studies have concentrated on testing different ways to mitigate the fouling. Ozonation process, that has been proved to reduce the MBR fouling, is studied in this project. Ozonation can provide the conditions for flocculation and therefor improves mixed-liqure properties. Ozon at two concentrations, 0.2 and 0.9 mg/lit was tested. Although results show little change in COD (chemical oxygen demand), but membrane...