Sammanfattning

Drinking water treatment residuals (DWTRs) generated during drinking water treatment have been proposed for use in lake restoration as a solid-phase sorbent to inactivate phosphorus (P) in lake sediment. However, treatments that minimize leaching of nitrogen (N) and optimize P sorption capacity may be necessary prior to use. This study assessed seven different treatment methods, including washing and heat treatments at different temperatures and with and without oxygen limitation, among two DWTRs from Thailand. Results showed that oxygen-limited heat treatment at 600 degrees C substantially reduced N leaching (<0.2 mg/kg TKN) while also improving P sorption capacity (increase of 18-32% compared to untreated DWTR) to a maximum of 45.7 mg P/kg. Washing with deionized water reduced N leaching if a sufficient volume was used but did not improve P sorption. Heating at 200 degrees C with or without the presence of oxygen did not improve N leaching or P sorption. Regression of P sorption parameters from a two-surface Langmuir isotherm against physio-chemical properties indicated that oxalate-extractable (i.e., amorphous) aluminum and iron were significantly associated with total P sorption capacity (R-2 = 0.94), but micropores and oxalate-extractable P modulated the P sorption from high-affinity to low-affinity mechanisms. In conclusion, this study confirmed the importance of amorphous aluminum in DWTRs for inactivating P, and the results suggest that high-temperature treatment under oxygen-limited conditions may be the most reliable way to optimize DWTRs for environmental remediation applications.

Nyckelord

adsorption; alum sludge; binding efficiency; biochar; coagulant; eutrophication; oxidation; pyrolysis

Publicerad i

Water
2021, Volym: 13, nummer: 18, artikelnummer: 2465

SLU författare

• Huser, Brian

  • Institutionen för vatten och miljö, Sveriges lantbruksuniversitet
    

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UKÄ forskningsämne

Vattenbehandling


Publikationens identifierare

DOI: https://doi.org/10.3390/w13182465

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/113670