Characteristics of dissolved organic matter in two alternative water sources: A comparative study between reclaimed water and stormwater

Reclaimed water and stormwater are two important alternative water sources to mitigate water resource shortage. They can be reused by discharging into drinking water sources. Due to different sources, characteristics of dissolved organic matter (DOM, a precursor of disinfection by-products, DBPs) present in reclaimed water and stormwater would be different. This study selected reclaimed water to compare with stormwater (including both stormwater runoff and rain-water) by investigating their DOM characteristics, including concentrations, aromaticity, molecular weight, hydropho-bicity/hydrophilicity, composition and DBPs formation potential. The results showed that reclaimed water had higher dissolved organic carbon (DOC) concentrations (6.02-10.8 mg/L) than stormwater (3.62-5.48 mg/L) while SUVA254 values of stormwater runoff (1.92-2.53 L/(mg-C & BULL;m)) were higher than reclaimed water (1.11-1.24 L/(mg-C & BULL;m)). Addi-tionally, reclaimed water is more hydrophobic while stormwater runoff and rainwater are more hydrophilic. Although all water types included the highest fraction of DOM with molecular weight < 1 kDa (43.0 %-77.5 %), reclaimed water primarily contained soluble microbial products (SMPs)-like and humic acid-like substances while stormwater runoff pri-marily contained humic acid-like DOM. In terms of DBPs, reclaimed water showed relatively higher formation potential than stormwater runoff while rainwater had the lowest DBPs formation potential. These results can contribute to effec-tive water resource management. Particularly, when reclaimed water or/and stormwater are discharged into drinking water sources, these outcomes can help on efficient drinking water treatment.

Automated summary

Reclaimed water and stormwater are important alternative water sources for mitigating water resource shortage. They have different characteristics of dissolved organic matter (DOM), with reclaimed water having higher DOC concentrations and more hydrophobic properties. Reclaimed water primarily contains SMPs-like and humic acid-like substances, while stormwater runoff primarily contains humic acid-like DOM. Reclaimed water has relatively higher formation potential of disinfection by-products (DBPs), while rainwater has the lowest formation potential.