Journal of Environmental Engineering Technology ›› 2011, Vol. 1 ›› Issue (4): 353-358.doi: 10.3969/j.issn.1674-991X.2011.04.060

• Special Issue:National Major Science and Technology Program for Water Pollution Control & Treatment • Previous Articles     Next Articles

Synergetic Treatment of Landfill Leachate in the Photoelectrochemical Process with Activated Carbon Fiber as Cathode

XIAO Shu-hu,SONG Yong-hui,XIAO Hong-kang,ZHANG Guo-fang   

  1. Department of Urban Water Environmental Research, Chinese Research Academy of Environmental Sciences
  • Received:2011-03-25 Revised:2011-05-04 Online:2011-07-20 Published:2011-07-11
  • Contact: XIAO Shu-hu E-mail:xiaoshuhu@126.com

Abstract: Photoelectrochemical treatment of landfill leachate with activated carbon fiber (ACF) cathode and RuO2/Ti anode was carried out. Firstly, the treatment efficiencies were compared among electro-oxidation, electro-oxidation/electro-Fenton and  photoelectrochemical processes. Then the effects of initial pH and current intensity were studied in details. Simultaneously, the variations of organic speciation and biodegradability were investigated. The results showed that the degradation efficiency and rate were by far higher than the sum of electro-oxidation and electro-oxidation/electro-Fenton, thus the hybrid photoelectrochemical process presented a good synergetic effect. The formations of hydroxyl and chlorine radicals, which were disassociated from H2O2 and active chlorine by UV and Fe2+, were proposed to be the main mechanism. Current density was the control factor and the degradation rate of TOC increased gradually with current density. Under the conditions of initial pH value of 2.0~5.1, current intensity of 15.0 mA/cm2, and Fe2+ addition of 1 mmol/L, the removals of TOC reached about 80% within 300 min and the first-order kinetic constants ranged between 6.1×10-3 ~ 6.6×10-3 min-1. UV-Vis and gel permeation chromatography (GPC) spectra showed that the biorefractory humic and fulvic substances could be transformed into small molecules or even be mineralized, which resulted in the increase of biodegradability and the BOD5/COD reached about 0.42.

Key words: Photoelectrochemical process, activated carbon fiber, landfill leachate, synergetic effect, biodegradability