Characterization and Differentiation of Wastewater Effluent Organic Matter (EfOM) Versus Drinking Water Natural Organic Matter (NOM): Implications for Indirect Potable Reuse
A major objective of this research was to investigate the characteristic differences/similarities between wastewater effluent organic matter (EfOM) and drinking water natural organic matter (NOM) derived from diverse water sources using multiple analytical and statistical techniques. Parallel factor analysis (PARAFAC), a three-dimensional statistical modeling technique, was applied to a dataset of excitation-emission matrix (EEM) of fluorescing organic matter components in order to identify organic matter fluorophores characteristic of EfOM versus NOM. Identified fluorophores were used to elucidate characteristic features of bulk organic matter as well as treatability of EfOM(-impacted waters) by conventional drinking water treatment processes. Results show that EfOM exhibits increased fractions of microbial-originated organic components of a hydrophilic nature. Size exclusion chromatographic (SEC) characteristics of EfOM and NOM reveal that EfOM is a mixture of various organic components which have different molecular weight distributions and light-absorbing properties. Incorporation of traditional NOM characterization results with multivariate statistical analyses shows that a hydrophilic fraction is a key discriminator of EfOM that differentiates it from NOM, and thus, the organic properties of any water source influenced by wastewater may be shifted to a more hydrophilic nature.The evaluation of wastewater impacts on existing drinking water treatment plant in terms of treatability of an organic matter was also an aim of this study. Lab-scale simulations of the coagulation process suggest EfOM has potentially negative impacts on drinking water treatment efficiency due to changed organic properties of source waters. Consequently, adoption of a biodegradation process such as soil aquifer treatment (SAT) or river bank filtration (RBF) is proposed as a strategic management
