Application of conventional biological treatment (aerobic and anaerobic) to industrial landfill leachate is usually limited by the presence of toxic contaminants (heavy metals) and recalcitrant (biopersistent) organics (polyphenols, pharmaceuticals, cosmetics as well as other chemicals), thus hindering viable conditions for biomass proliferation in biological reactors, with related difficulties in meeting maximum allowable concentrations for discharge imposed by the applied regulations. Fe2+-H2O2-H+ mixture (Fenton's reagent) may be used as a pre-treatment of industrial landfill leachate for preliminary abatement of the organic load and to improve biodegradability in terms of BOD/COD ratio to figures higher than 0.4 to favour biological oxidation in conventional wastewater treatment plants. Leachate from Groftaglie (S.E. Italy) industrial landfill (pH 8.6; COD=11.000 mg/L; BOD5=2.400 mg/L; NH4-N=2.900mg/L; conductivity=60.000 mu S/cm) was tested at laboratory scale in different operative conditions, i.e., initial pH, Fe2+/H2O2 concentrations and ratio, reaction time. Oxidation reaction was monitored by equilibrium pH and residual COD and BOD5 concentrations. Best operative conditions were obtained at pH 3, Fe2+=700 mg/L, H2O2=9,900 mg/L (H2O2/Fe(2+)ratio similar to 13 w/w), reaction time=2h. Following the oxidation reaction, solution pH was neutralized by the addition of Ca(OH)(2) or NaOH (120 meq/L) for further removal of target parameters by precipitation/sorption phenomena. A technical/economical evaluation of potential process schemes for oxidative pretreatment of industrial landfill leachate is also given in the paper.
|Titolo:||Advanced oxidation as a pre-treatment of industrial landfill leachate|
|Data di pubblicazione:||2005|
|Nome del convegno:||9th International Conference on Environmental Science and Technology|
|Appare nelle tipologie:||4.1 Contributo in Atti di convegno|