Efficiency analysis of the electrocoagulation and electroflotation treatment of poultry slaughterhouse wastewater using aluminum and graphite anodes

Environ Sci Pollut Res Int. 2018 Jul;25(20):19790-19800. doi: 10.1007/s11356-018-2184-y. Epub 2018 May 8.

Abstract

The application of electrocoagulation (EC) and electroflotation (EF) was investigated for the treatment of poultry slaughterhouse wastewater in a bench scale unit cell electrolyzer with different EC-to-EF ratios at current densities of 3, 9, and 15 mA cm-2. The EC-to-EF ratio was controlled by current reversal using aluminum and graphite electrodes. The electrochemical treatment showed satisfactory removal efficiencies for Al coagulant loads greater than 51.8 mg L-1. The 4/5 EC to EF ratio (69.1 mg L-1 Al and 32.2 NmL L-1 additional EF gas) and 3/5 (51.8 mg L-1 Al/64 NmL L-1 additional EF gas) presented the best results for the removal of COD (76-85%), color (93-99%), and turbidity (95-99%), with the additional benefit of reducing the electrode consumption and sludge disposal costs proportionally to the EC-to-EF ratio. The effects of the EC-to-EF ratio and the current density on efficiency of the electrochemical treatment for the removal of COD, apparent color, turbidity, TSS, TSD, and NH3-N were discussed in the light of the physicochemical and electrochemical processes underlying the removal mechanism for each parameter. In particular, the blow-off mechanism seems to play an important role in the NH3-N removal, whereas indirect electrooxidation mechanism accounts for a fraction of the soluble COD removal for the electrodes configuration used in the treatment.

Keywords: Electrochemical treatment; Electrocoagulation; Electroflotation; Poultry slaughterhouse; Removal mechanism; Wastewater.

MeSH terms

  • Abattoirs*
  • Aluminum / chemistry*
  • Animals
  • Electrocoagulation / methods
  • Electrodes
  • Graphite / chemistry*
  • Poultry
  • Waste Disposal, Fluid / methods*
  • Waste Water / chemistry*
  • Water Purification / methods

Substances

  • Waste Water
  • Graphite
  • Aluminum