Vegetable tannery wastewaters contain high concentrations of organics and other chemicals that inhibit the activity of microorganisms during biological oxidations, so biorefractory organics that are not removed by biological treatment must be eliminated by a tertiary or advanced wastewater treatment. In this paper, the applicability of electrochemical oxidation as a tertiary treatment of a vegetable tannery wastewater was investigated by performing galvanostatic electrolysis using lead dioxide (Ti/PbO2) and mixed titanium and ruthenium oxide (Ti/TiRuO2) as anodes under different experimental conditions. The experimental results showed that both the electrodes performed complete mineralization of the wastewater. In particular, the oxidation took place on the PbO2 anode by direct electron transfer and indirect oxidation mediated by active chlorine, while it occurred on the Ti/TiRuO2 anode only by indirect oxidation. Furthermore, the Ti/PbO2 gave a somewhat higher oxidation rate than that observed for the Ti/TiRuO2 anode. Although the Ti/TiRuO2 required almost the same energy consumption for complete COD removal, it was more stable and did not release toxic ions, so it was the best candidate for industrial applications. With the Ti/TiRuO2 anode, the rate of tannery wastewater oxidation increased with the current density, pH, and temperature of the solution. These results strongly indicate that electrochemical methods can be applied effectively as a final treatment of vegetable tannery wastewater allowing the complete removal of COD, tannin, and ammonium and decolorization.

Electrochemical Oxidation as a Final Treatment of Synthetic Tannery Wastewater

PANIZZA, MARCO;CERISOLA, GIACOMO
2004-01-01

Abstract

Vegetable tannery wastewaters contain high concentrations of organics and other chemicals that inhibit the activity of microorganisms during biological oxidations, so biorefractory organics that are not removed by biological treatment must be eliminated by a tertiary or advanced wastewater treatment. In this paper, the applicability of electrochemical oxidation as a tertiary treatment of a vegetable tannery wastewater was investigated by performing galvanostatic electrolysis using lead dioxide (Ti/PbO2) and mixed titanium and ruthenium oxide (Ti/TiRuO2) as anodes under different experimental conditions. The experimental results showed that both the electrodes performed complete mineralization of the wastewater. In particular, the oxidation took place on the PbO2 anode by direct electron transfer and indirect oxidation mediated by active chlorine, while it occurred on the Ti/TiRuO2 anode only by indirect oxidation. Furthermore, the Ti/PbO2 gave a somewhat higher oxidation rate than that observed for the Ti/TiRuO2 anode. Although the Ti/TiRuO2 required almost the same energy consumption for complete COD removal, it was more stable and did not release toxic ions, so it was the best candidate for industrial applications. With the Ti/TiRuO2 anode, the rate of tannery wastewater oxidation increased with the current density, pH, and temperature of the solution. These results strongly indicate that electrochemical methods can be applied effectively as a final treatment of vegetable tannery wastewater allowing the complete removal of COD, tannin, and ammonium and decolorization.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11567/215304
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 256
  • ???jsp.display-item.citation.isi??? ND
social impact