Removal, biodegradability, detoxification, and risk assessment of direct and indirect reclaimed water contaminated with 4-chloroaniline using ozonation and electro-peroxone processes

Information from the abstract

Direct and indirect water reuse have been proposed as a sustainable strategy to mitigate the global water scarcity crisis. Presence of emerging contaminants, such as 4-chloroaniline (4-CA) in reclaimed water raises concerns. In this study, ozonation (OZ) and electro-peroxone (EP) processes were investigated for removal of 4-CA and dissolved organic matter (DOM) with emphasis on the change in disinfection byproduct formation potential (DBPs FP), cytotoxicity, and health risk. We found that OZ and the EP substantially removed 4-CA, while 30.75–39.19% of DOM was mineralized, and biodegradability of 4-CA-contaminated water was enhanced by EP. Fluorescence excitation–emission matrix spectroscopy confirmed that 4-CA was largely oxidized. The concentrations of trihalomethanes (2.60–291.30 µg/L) and haloacetonitriles (0.23–18.58 µg/L) in the treated 4-CA-contaminated water remained below drinking water guideline values. Statistically, 4-CA had less influence on DBPs FP than DOM. However, cytotoxicity assays in HepG2 cells revealed that residual 4-CA concentration, DBPs FP and background water characteristics likely impacted toxicity. For assessment of health risks, 4-CA posed both non-carcinogenic (HQ) and carcinogenic (CR) risks whereas both OZ and EP markedly reduced these risks. However, the OZ and EP conditions tested did not achieve the target carcinogenic risk level, highlighting the need for further process optimization before reuse.

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Related topics: Advanced oxidation water treatment · Water Treatment and Disinfection · Environmental remediation with nanomaterials