The stability of drinking water treatment residue with ozone treatment

The best management of drinking water treatment residue (DWTR) in environmental remediation should be based on comprehensively understanding the effectiveness and risk of DWTR. In this study, the variation in physicochemical properties, metal lability, and adsorption capability of DWTR under oxidizing condition were investigated. The oxidizing condition was set up using ozone treatment, and the laboratory incubation test were performed within 50 d in association with thermogravimetry, Fourier Transform Infrared Spectrometry, specific surface area and porosity analyzer, fractionation, and P adsorption test. The results showed that ozone treatment had limited effect on the properties of organic matter, the lability of Al, Cu, and Fe, the P adsorption capability, and the distributions of the adsorbed P in DWTR, but the treatment increased N₂ sorption/desorption, specific surface area, total pore volume of DWTR and led to the transformation of Mn from acid-soluble to reducible fractions. These findings demonstrated that DWTR generally kept stable under oxidizing environment; even oxidizing environment may induce a tendency of increasing the adsorption capability and decreasing the environmental risk of DWTR. Accordingly, the effectiveness and safety of DWTR can be maintained under natural aerobic environment, and DWTR is a reliable adsorbent that could be recycled in environmental remediation.