Integrated fluorescence and biodegradability indicators for predicting disinfection by-product formation potential and guiding treatment optimization in resource-limited settings

The study demonstrated the effectiveness of integrating biodegradability assessment, fluorescence spectroscopy, optical indices, and bulk organic carbon metrices in evaluating and predicting disinfection byproduct formation potential (DBPFP) in chlorinated surface waters. Results indicated a natural organic matter (NOM) pool rich in conjugated and aromatic structures exhibited by a (dissolved organic carbon) DOC concentration of 2.87 mg/L and elevated UV254 absorbance of 0.226 cm−1 and specific UV absorbance (SUVA) value of 7.86 L/mg m−1. Elevated levels of trichloromethane (TCM) (54.48 μg/L) among the trihalomethanes (THMs) complement the bulk parameters results, given that electron-rich aromatic groups influence the formation of TCM via electrophilic substitution during chlorination. Furthermore, the study demonstrated that even modest DOC levels can result in significant DBP formation if the precursor is sufficiently aromatic, this was further demonstrated by elevated SUVA values which is a measure of reactivity per unit carbon. The fluorescent peak intensities delivered further granularity. High intensities for Peak T and Peak B (0.382 RU and 0.468 RU, respectively), corresponding to tryptophan-like and tyrosine-like fluorophores indicated a strong contribution from low molecular weight proteinaceous NOM, typically linked to microbial activity. The study proposed a dual strategy for effective DBP control by: (1) reducing aromatic, humic-like constituents through adsorption or enhanced coagulation, and (2) reducing biodegradable fractions of low molecular weight via advanced oxidation or biological filtration. Combined, the multi-dimensional approach enables an adaptable and targeted approach to addressing emerging and regulated DBP species in raw waters.