Promotion of oil hydrocarbon degradation in fine-grained marsh soils under aerobic and denitrifying conditions

摘要

The goal of the laboratory studies was to prove oil hydrocarbon degradation in fine-grained inarsh soils under denitrifying conditions and to compare it with the degradation under aerobic conditions. In order to accelerate the bioremediation processin soils with redox potentials < + 200 mV (pH 7) the use of different additives and oxidizing agents was tested. Fine-grained soil materials from marsh soils was treated with KNO_3, fertilizers or a mixture of both for the hydrocarhon degradation underanoxic denitrifying conditions as well as the addition of hydrogen peroxide or an oil binder to improve the soil structure to promote aerobic hydrocarbon degradation. During the incubation period, soil respiration (CO_2-production) was measured nearly every day, the content of hydrocarbons as well as the number of microbial hydrocarbon degraders (aerobic, anaerobic), NH_4~+-N, NO_3~--N and total N was measured at the beginlfing of the test and after two and four weeks. There were several indicators forthe hydrocarbon degradation under denitrifying conditions: high denitrification rates, an increase in colonization with denitrifying bacteria, higher respiratory quotients and higher degradation rates compared to the reference. At the end of the test period the oil binder treated soil had the highest degradation rate, but there were severe differences in the degradation rate between the first and second fortnight of all treatments. Our investigation suggests that combined KNO_3 and fertilizer treatmentis the most promising treatment to accelerate biological hydrocarbon degradation in fine-grained inarsh soils and should be tested in the near future in biopiles.