Treatment of crystallized-fruit wastewater by UV-A LED photo-Fenton and coagulation-flocculation

Chemosphere. 2016 Feb:145:351-9. doi: 10.1016/j.chemosphere.2015.11.092. Epub 2015 Dec 12.

Abstract

This work reports the treatment of crystallized-fruit effluents, characterized by a very low biodegradability (BOD5/COD <0.19), through the application of a UV-A LED photo-Fenton process. Firstly, a Box-Behnken design of Response Surface Methodology was applied to achieve the optimal conditions for the UV-A LED photo-Fenton process, trying to maximize the efficiency by saving chemicals and time. Under the optimal conditions ([H2O2] = 5459 mg/L; [Fe(3+)] = 286 mg/L; time >180 min), a COD removal of 45, 64 and 74% was achieved after 360 min, using an irradiance of 23, 70 and 85 W/m(2) respectively. Then a combination of UV-A LED photo-Fenton with coagulation-flocculation-decantation attained a higher COD removal (80%), as well as almost total removal of turbidity (99%) and total suspended solids (95%). Subsequent biodegradability of treated effluents increased, allowing the application of a biological treatment step after the photochemical/CFD with 85 W/m(2).

Keywords: Biodegradability; Coagulation/flocculation; Crystallized-fruit wastewater; Photo-Fenton; UV-A LED.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteria / metabolism
  • Crystallization
  • Flocculation
  • Fruit*
  • Hydrogen Peroxide / chemistry*
  • Iron / chemistry*
  • Light*
  • Oxidation-Reduction
  • Waste Disposal, Fluid / methods
  • Wastewater / chemistry
  • Water Pollutants, Chemical / chemistry*
  • Water Pollutants, Chemical / radiation effects*

Substances

  • Waste Water
  • Water Pollutants, Chemical
  • Hydrogen Peroxide
  • Iron