Bioaugmentation as a strategy to reduce the uncertainty of biological nutrient removal in granular sludge systems

点击翻译按钮获取中文摘要

This research program will address a major problem related to wastewater treatment: how to reduce the uncertainty of biological nutrient removal. The approach to the research will combine mathematical modelling and experimental testing of an innovative strategy for bioprocess engineering. The removal of nutrients (nitrogen and phosphorus) plays a major role in the overall cost of wastewater treatment. Biological nutrient removal (BNR) is the most economically and environmentally sustainable state-of-the-art technology. However, a degree of uncertainty is still related to BNR design and operation. The selection and the separation from the liquid of the microbial consortia operating biodegradation and nutrient removal are the main problems to be faced. The selection of phosphorus accumulating bacteria (PAO) is a very effective strategy for a sustainable removal and recovery of phosphorus. Moreover, the recent development and application of granular sludge technologies represents a promising approach to improve solid-liquid separation and to reduce the size of the plants especially in cold climate regions. Both solutions are not always suitable, depending on the context, with actual technologies. Granular sludge formation presents some critical aspects related to granules formation and stability and the selection of PAO strictly depend on the competition with glycogen accumulating bacteria. Due to the high flow rates of wastewater, it is too expensive to control some important parameters of wastewater (such as the composition, pH and temperature) for process control. Thus, it is important to find alternative strategies to drive the selection in the plant ecosystem. My team and I propose an innovative approach, based on the selection of the desired microbial community in a controlled side stream reactor, to be used as continuous inoculum for mainstream reactors (bioaugmentation). This will facilitate the design and operation of wastewater treatment plants for biological nutrient removal and will offer an insight in to new aspects of environmental bioprocess engineering. The results of the research will have a potential impact and future application in environmental technologies other than BNR.