A LABORATORY SCALE STUDY OF NITRIFICATION USING TRADITIONAL AND MOLECULAR ANALYTICAL TECHNIQUES

Biological removal of contaminants is an integral part of many wastewater treatment plants. Current treatment practices for municipal wastewater utilizing activated sludge are hindered by the lack of microbial population and per cell activity data. Recent advances in molecular biology have yielded unprecedented opportunities for insight into the microbial community structure of activated sludge. Together with traditional microbial analyses, these techniques offer an opportunity to better define treatment performance. An understanding of microbial dynamics during biological treatment could be used to improve process design and control, and to develop more efficient biotreatment strategies. Research documented herein represents an initial attempt to elucidate the speciation and activity of nitrifying bacterial populations using genetic probes. Bench scale activated sludge reactors were operated at various sludge ages under excess dissolved oxygen levels and at 20°C for five months. A number of analytical methods were utilized to evaluate treatment performance and population dynamics. Eventually studies of the nitrifying community structure and population dynamics will be expanded to investigate the effect of a variety of operational parameters including limited dissolved oxygen concentrations and a wide range of process temperatures.