Anaerobik çıkış atıksuyunda mikroyosunun çoğaltılması

The reduction of petroleum resources together with monetary and environmental concerns, drive us to find the new alternative and sustainable energy sources. Therefore, microalgae have received an increasing attention more than ten years. However, the results of the projects were not promising to consider the microalgae as an alternative solution. To make this process commercially feasible, new approaches and methodologies are necessary. Coupling microalgae growth for valuable biomass production and wastewater treatment can be one of the sustainable solutions in terms of not only for alternative energy production, but also for the environmental protection. Anaerobic digestion effluent contains high amounts of nitrogen and phosphorus, which are essential for microalgal growth. This study consists of two parts. In first part, growth of microalgae in different dilution rates of anaerobic digestion effluent is investigated. All dilutions were made with tap water and reactors were run in contionous illumunation with constant light intensity.Cell densities reached 0.625 g/L as dry weight in 20% diluted reactors and lowest dilution rate of considerable microalgal growth is found to be 40% diluted reactors with cell density reaching up to 0.530 g/L as dry weight. In second part, growth in lowest appropriate dilution rate (40%) was investigated with phosphorus addition, due to phosphorus limitation of cells in first part of series. Phosphorus concentrations were adjusted to 0.5, 1, 2 and 4 times of phosphorus concentration of BG-11. Growth of microalgae with phosphorus addition was more efficient than in first part of experiment with cell density reaching up to 0.881 g/L in reactors, which have same concentration of phosphorus with BG-11 medium. No pH adjustment was made and buffer solution was added to cultures, therefore there was a dramatic decline in pH values, in second part of the experiments, pH of reactors dropped to 4-5 at the end of experiments. Lower growth efficiency comparing to cultures grown in BG-11 medium is attributed to decline of pH due to lack of buffer capacity, acclimation problems of BG-11 grown cells to wastewater lower photosynthetic efficiency due to color of wastewater and competition with other microorganisms due to non-sterile conditions.