Fenton's pre-treatment of mature landfill leachate.
The aim of this study was to check the effectiveness of the Fenton's reagent (Fe2+ + H2O2 + H+) for the pre-treatment of a municipal landfill leachate with the objective of improving its overall biodegradability, evaluated in terms of BOD5/COD ratio, up to a value compatible with biological treatment. The leachate came from a municipal sanitary landfill located in southern Italy and the average values of its main parameters were: pH=8.2; COD=10,540 mgl(-1); BOD5=2,300 mgl(-1); TOC=3,900 mgl(-1); NH4-N=5210 mgl(-1); conductivity=45,350 microScm(-1); alkalinity=21,470 mgl(-1) CaCO3. The effect of initial pH value on the pre-treatment effectiveness was evaluated by titrating the amount of acidic by-products formed. The extent of leachate oxidation was monitored and controlled by both pH and redox potential measurements. The best operational conditions for achieving the desired goal (i.e., BOD5/COD> or =0.5) resulted: Fe2+=275 mgl(-1); H2O2=3,300 mgl(-1); initial pH=3; reaction time=2 h. At the end of the Fenton's pre-treatment, in order to permit a subsequent biological treatment, residual ferric ions were removed increasing the pH up to 8.5 by adding 3 gl(-1) of Ca(OH)2 and 3 mgl(-1) of a cationic polyelectrolyte, the latter as an aid to coagulation. This final step also resulted in a further modest removal of residual COD due to co-precipitation phenomena.
Lopez
Antonio
A
Consiglio Nazionale delle Ricerche, Istituto di Ricerca Sulle Acque, Reparto di Chimica e Tecnologia delle Acque, Via Francesco De Blasio, 5, 70123 Bari, Italy. an.lopez@area.ba.cnr.it
Pagano
Michele
M
Volpe
Angela
A
Di Pinto
Appio Claudio
AC
D006861:Hydrogen Peroxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D007558:Italy; D007700:Kinetics; D010100:Oxygen / Q000737:chemistry; D012037:Refuse Disposal; D014873:Water Pollutants / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
C045076:Fenton's reagent; D014873:Water Pollutants; D006861:Hydrogen Peroxide; D007501:Iron; D010100:Oxygen