Effect of various chemical oxidation agents on soil microbial communities

Chemical oxidations by hydrogen peroxide and/or persulfate represent promising pretreatment step foregoing bioremediation for removal of hydrophobic contaminants. The feasibility of hydrogen peroxide-based and sodium persulfate-based oxidation treatments on the real contaminated soil collected from petroleum lagoon deposit were evaluated. The results showed poor insignificant degradation of pollutants (expressed as C10-C40 concentration) in hydrogen peroxide variants (avg. of 9% ± 30% decrease) in comparison to persulfate treatment variants (avg. of 55% ± 13% decrease). In accordance, microbial community activity indicators showed substantial inhibition of viability only by persulfate, base and Fe3+ activated variants. The highest contaminant removal efficiency was achieved by Fe3+ activated persulfate system (78% ± 3%). Persulfate was thus demonstrated as a promising chemical oxidant for degradation of petroleum contaminants, however activation mechanism and initial dosage of the oxidant should by chosen carefully in respect to the soil microorganisms.