Abstract
Activated sludge is a common wastewater treatment technology that uses diverse consortia ofmicroorganisms to transform or remove regulated compounds such a phosphorus and ammonia.
Activated sludge facilities are designed around bacterial metabolisms that are induced through
changes in environment. These metabolisms are vital to the physiochemical reactions that allow
wastewater treatment plants to meet their permit limits, however they are rarely measured directly.
Instead, wastewater engineers, operators, and scientists rely on process models and more indirect
measurements of metabolic activity. While these conventional metrics are sufficient for most needs,
the increasing complexity of wastewater treatment plants and stricter effluent permit limits have
created a demand for more sophisticated tools such as metabolomics.
Metabolomics is the study of the small molecules which serve as substrates, intermediates, and
products in metabolisms. Metabolomic methods allow for the detection of hundreds of compounds in
one analysis, making the tool an appealing alternative to the more widely used transcriptomics, which
requires specific target genes and primers. Metabolomics is widely applied in fields such medicine,
nutrition, and agriculture, but has had limited application to the field of wastewater treatment so far.
Research at the University of Idaho is focused on using metabolomics to better characterize and
describe nutrient removal in activated sludge processes, with the ultimate aim of generating new
knowledge on process operation and control. This thesis evaluates the application of both
metabolomics and conventional metrics to a variety of activated sludge process configurations,
including benchtop batch reactors and full-scale wastewater treatment plants. Metabolomics data was
used for method improvement, metabolome fingerprinting, comparison of process configurations, and
analysis of a xenobiotic rich waste stream. This assortment of applications provided insight into what
role metabolomics may play in understanding activated sludge metabolisms moving forward.