Article

Pretreatment of stabilized leachate using ozone/persulfate oxidation process

Chemical Engineering Journal (Impact Factor: 3.47). 01/2013; 221. DOI: 10.1016/j.cej.2013.02.038

ABSTRACT A combination of ozonation and persulfate ðO3=S2O2� 8 Þ was used to treat stabilized landfill leachate. COD,
color, and NH3–N, ozone and persulfate doses, pH and reaction time were evaluated to define the optimum
operational conditions. The results indicated that under optimum operation conditions (i.e.
210 min of ozonation, a COD=S2O2� 8 ratio (1 g/7 g), and pH 10), the best removal values of COD, color,
and NH3–N were 72%, 93%, and 55%, respectively. The biodegradability (BOD5/COD ratio) has improved
from 0.05 to 0.29. The ozone consumption for COD removal was 0.76 kg O3/kg COD. The results obtained
by employing the combined use of persulfate and ozone were compared with those by employing ozone
only and persulfate only. The results achieved with the combined use of persulfate and ozone were compared
with those obtained with ozone only and persulfate only. The combined method (i.e., O3=S2O2� 8 )
achieved higher removal efficiencies for COD, color, and NH3–N compared with other studied applications.
Additionally, the combined of ozone/persulfate method proved to be more efficient than the combined
use of ozone/Fenton in advanced oxidation processes in the treatment of the same studied leachate.

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    ABSTRACT: The effluents of some pulp and paper processes are potentially pollutant, because of their large volume and their refractory nature. Biological processes generally are not capable to remove these compounds. Advanced Oxidation Processes (AOP) are characterized by the capability of exploiting the high reactivity of HO • radicals. AOP can produce a total mineralization, transforming recalcitrant compounds into inorganic substances (CO 2 and H 2 O 2), or partial mineralization, transforming them into more biodegradable substances. The high reactivity and low selectivity of these radicals are useful attributes that that make these processes in promising technologies. Due to the differences between pulping processes, the effluents from the various processes and operations of such industries also differ from each other, so that some oxidative processes should be combined to improve the removal efficiency. For the effective oxidation of refractory organic compounds, hydroxyl radicals should be generated continuously in situ due to its chemical instability. Generation of HO • is commonly accelerated by combining oxidizing agents. Among these treatments, UV radiation plus hydrogen peroxide (UV/H 2 O 2), Fenton's reagent (H 2 O 2 /Fe +2), photo-Fenton (UV/H 2 O 2 /Fe +2), and ozone in different combinations (O 3 /UV; O 3 /H 2 O 2) are considered to be effective for the oxidation of effluents from pulp and paper industries.
    American Journal of Environmental Engineering. 05/2014;

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May 29, 2014