Nitrifying Community Structure and Nitrification Stability under Extreme Environments

Biological nitrogen removal (BNR) is the most environmental friendly and economic method for protecting natural water bodies and drinking water sources from nitrogen contaminant pollution. Especially when reuse of wastewater is of important in the 21th century, many Taiwan industrial wastewaters with a low C/N ratio require nitrogen removal before they can be reused. In this three-year proposal, we plan to evaluate the correlation between nitrification feasibility, inorganic carbon limitation, and microbial ecology of ammonia-oxidizing microorganisms, under extreme environments such as wastewaters with a low C/N ratio. Through integrated knowledge and application of molecular methods for understanding microbial community dynamics of ammonia-oxidizing microorganisms, information of environmental and operational variables, and systematic analysis using statistical methods, the nitrification stability can finally be understood, predicted, and controlled. Another goal of this project is to inaugurate a network of bioreactor observatories at wastewater treatment plants around the globe. Originally initiated by Dr. Craig Criddle, Professor of Civil and Environmental Engineering at the Stanford University, now there are more than 10 laboratories from USA, UK, South Korea, Singapore, Hong Kong, China, Thailand, Puerto Rico, and Taiwan joining this international collaboration to elaborate on the application of modern molecular tools to understand microbial community dynamics over time and to relate changes in dynamics to geographic and operational variables. The current target of this international collaboration is to study the correlation between nitrification stability, environmental and operational variables, and microbial ecology of ammonia-oxidizing microorganisms. With information collected from wastewater treatment plants located at different countries, we anticipate to establish a platform for a global network of bioreactor observatories that can improve operational strategies for nitrification stability at wastewater treatment plants.