Sharif Digital Repository

The pollution of water resources with heavy metals as a result of industrial activities threatens the lives of all living organisms. Therefore, separation of heavy metals from wastewater before entering our invironment is very important. Various chemical and physical methods such as absorption, chemical precipitation, extraction by solvent and ion exchange can be used to separate heavy metals but each of these methods have their own problems such as imperfect separation of heavy metals, need for expensive facilities and refining systems, high energy consumption and leaving pollutant residuals that need to be separated. On the other hand, the methods mentioned above can not separate heavy... 

Microalgae is a major problem in water resources due to its adverse influence on water treatment process and water quality like color, odor and taste. In addition microalgae removal is an important process in food and pharmacy industry. Electrocoagulation is a potential method for microalgae removal. Another method for microalgae recovery is membrane treatment. This study is focusing on using both methods separately and simultaneously. To achieve this, the removal of Chlorella Vulgaris, a fresh water microalgae, was used in experiments. In first phase the experiments were solely on electrocoagulation and the effect of several parameters including current density, electrocoagulation duration,... 

If wastewater is not properly treated, then the environment and human health can be negatively impacted. These impacts can include harm to fish and wildlife populations, oxygen depletion and contamination of drinking water. In the typical wastewater treatment process, the goal of primary, secondary and tertiary effluent treatment is to reduce or remove organic matter, solids, nutrients, disease-causing organisms and other pollutants from the treated wastewater before it is discharged to a body of water. Biological methods for wastewater treatment are much preferable for being more economical and environmentally friendly. Biological treatment of wastewater using algal-bacterial culture... 

The experimental investigation of biodiesel production stages from microalgae especially biomass production stage was conducted in this thesis. The optimal rate of biomass productivity was determined.
A photobioreactor was designed and constructed to cultivate microalgae C. Vulgaris according to researchers’ works and obtained results in this study. The process parameters were examined and the optimal parameters were obtained according to the necessary tests which were carried out.
According to the results, the optimal condition for growing of microalgae was obtained with aeration of 6 lit/min with 3% CO2, and CO2 injection regime of 45 sec. injection and 3 min. of stoppage. A rapid... 

The experimental investigation of biodiesel production stages from microalgae especially lipid extraction stage was conducted in this thesis. The optimal rate of biomass productivity and optimal method in lipid extraction for biodiesel production was determined.
A photobioreactor was designed and constructed to cultivate microalgae C. Vulgaris according to researchers’ works and obtained results in this study. The process parameters were examined and the optimal parameters were obtained according to the necessary tests which were carried out. Then, several methods of lipid extraction using different solvents such as chloroform, methanol, and n-hexane were investigated and the best... 

In this study, different stages of biodiesel production from microalgae were investigated, specifically the extraction step.Various cultivation methods were also studied among which cultivation under stress was the best. Different carbon sources were also investigated to achieve highest growth. Sodium acetate with complete growth was achieved after 8 days with 6.22% fatty acid recovery. Different mixtures of solvents were compared with Blye and Dier method. Results showed that the mixture of hexane and methanol with crude lipid extraction of 15% and fatty acid recovery of 3.97% were chosen as the solvent mixture of equilibria experiments.Organic solvent composed of hexane (non-polar... 

In this research, experimental study and modeling of biodiesel production process from microalgae has been investigated. First, to have a biomass with suitable lipid content, a novel two-step process based on cultivation under nutrient sufficient followed by cultivation under nitrogen starvation condition has been proposed. Then the effect of using different organic and inorganic carbon sources on this process has been investigated which the results indicated that sodium acetate had a better performance compare to other carbon sources. In the following, the effect of using different light regimes on growth rate, lipid content and fatty acid composition have been investigated. Experimental... 

Nowadays, one of the most basic human problem is how to manage energy resources for sustainable development and how to deal with problems caused by growing energy consumption. Various scenarios are being discussd that the most important of them can be considered research on finding alternative energy sources that are renewable and do not have common pollution. Thus, according to researches carried out until now, using sources such as wind, water, solar biomass, etc. have been proposed. However, due to problems in the development of each of these sources, biomass as the primary option has been introduced. because biomass has several subsidiaries, research shows microalgaes (as a subset) are... 

Microbial Fuel cells (MFCs) can be used to generate bioenergy in the form of electricity by using microorganisms and natural biological processes. The need for a supply of fresh water in many parts of the world has led to the innovation of modifying an MFC into a Microbial Desalination Cell (MDC) that adds the function of desalination to the MFCs existing ability to generate electricity directly from wastewater. The goals of this project were to design and analyze the use of a Microbial Desalination Cell (MDC) for the generation of electricity while simultaneously desalinating saline water and also to evaluate performance of bio-cathode in MFCs and MDCs. The newly designed MDC incorporates...