DEGRADATION EFFICIENCY AND MECHANISM OF PIGGERY DIGESTATE BY OZONE AERATED INTERNAL FERRIC-CARBON MICRO-ELECTROLYSIS REACTOR

摘要

Ozone aerated internal micro-electrolysis (OIME) with a newly designed Fe-C particles filler was applied to treat the piggery digestate wastewater. The average COD, NH3-N and pH of the piggery di-gestate wastewater are 2000?2500 mg/L, 400?800 mg/L and around 8. The OIME process exhibited excellent COD (75.71%) and TOC (62.37%) removal efficiencies under the conditions: pH = 8, air flow rate = 60 L/h. Meanwhile, this process was effective to enhance biodegradability of the piggery digestate wastewater. The results showed that OIME process could be operated in wide pH range, while the optimum pH for piggery digestate wastewater was around 8.0. It was found that ozonation, Fe2+/Fe3+ catalyzed ozonation, the redox reactions of electro-reduction and electro-oxidation were the most important mechanisms in OIME process. The catalytic effect of Fe2+/Fe3+ would induce mutual conversion between dissolved Fe2+ and Fe3+, and then decrease the dissolution rate of zero valent iron (ZVI). The OIME process exhibited excellent removal efficiency under both natural and alkaline conditions, manifesting that the OIME process is one promising technology applied for piggery digestate wastewater and other refractory wastewater treatment.