Electrochemical oxidation of leachate pretreated in an upflow anaerobic sludge blanket reactor

Environ Technol. 2001 Apr;22(4):373-81. doi: 10.1080/09593332208618266.

Abstract

This study was conducted to develop a two-stage process for the treatment of Hong Kong leachate. The leachate, containing 4750 mg l-1 of chemical oxygen demand (COD) and 1310 mg l-1 of ammoniacal nitrogen (NH3-N), was first treated in a UASB (upflow anaerobic sludge blanket) reactor at 37 degrees C. The process removed on average 66.1% of COD with 6.1 days of hydraulic retention time (HRT), corresponding to an organic loading rate of 0.78 g-COD (l.day)-1. The UASB effluent, which had an average pH of 8.9, COD of 1610 mg l-1 and NH3-N of 1480 mg l-1, was then further treated by electrochemical oxidation in a batch reactor with recirculation. With the addition of 2000 mg l-1 of chloride (in the form of sodium chloride) and at a current density of 32.3 mA cm-2, 87% of COD and 100% of NH3-N were removed from the UASB effluent in six hours. The energy consumption was < 55 kWh kg-COD-1. The final effluent contained no residual NH3-N and only 209 mg l-1 of COD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Electrochemistry
  • Oxidation-Reduction
  • Oxygen / chemistry
  • Refuse Disposal / methods*
  • Sewage / chemistry*
  • Water Pollution / prevention & control

Substances

  • Sewage
  • Oxygen