Browsing by Author "Suppula, Veera"

The change in land use creates pressure for the remediation of polluted land areas. In Finland, the most common remediation method is soil replacement, which is a reliable, but expensive and emission-rich method. Alternative, more environmentally friendly methods are constantly being developed. In this thesis, the effect of a fractional mixture of organic matter on the degradation of petroleum hydrocarbons (> C10-C40) and polyaromatic hydrocarbons (PAHs) in soil was studied in pilot-scale experiments. Petroleum hydrocarbons and PAHs are common pollutants, and they are released into the environment as continuous emissions and from accidents. Due to their low volatility and high hydrophobicity, these pollutants degrade slowly in the environment and can be harmful to organisms. Soil organic matter has been found to promote the microbiological and chemical transformation of the pollutants in question, despite its ability to also prevent transformation by retaining the compounds by sorption. The effect of a fractional mixture of organic matter called OrgRemed® on the degradation of hydrocarbons and PAHs was studied for 6 months with two different mixture concentrations (1.25 % and 2.5 %) and the results were compared to natural attenuation and biostimulation with inorganic nutrients. The mixture enhanced the degradation of petroleum hydrocarbons, with a 2.5 % concentration resulting in the fastest degradation. With the fractional mixture, the total petroleum hydrocarbon concentration decreased 67-73 % in 4 months, while in biostimulation and natural attenuation 73 % and 37 % decrease was observed in 6 months, respectively. Petroleum hydrocarbon concentrations did not decrease further after 4 months with fractional mixture. The concentrations of PAHs in soil were low (11±4,9 mg/kg) and no degradation was detected. The results of petroleum hydrocarbon study are promising, but further research of residual concentrations, existing microbiota, and the effects of the mixture on PAHs degradation is needed.