Purification Effect of Bioremediation for Petroleum-contaminated Kunigami-maji Soil

Abstract

Biostimulation of a petroleum-contaminated soil is a remediation technique that stimulates indigenous microorganisms capable of degrading pollutants aided with the addition of phosphorus, nitrogen compounds, and oxygen. This study was conducted to evaluate the purification effect of bioremediation for petroleum-contaminated Kunigami-maji soil in the northern part of Okinawa Island. The soil remediation tests in our laboratory showed that the concentration of petroleum hydrocarbons decreased in the primary reaction and removal rate constants varied depending on the conditions of soil water contents and supply of nutrients and oxygen. It was concluded that the addition of nutrients and aeration of the soil were effective in enhancing purification when the gravimetric water content is adjusted to less than 23%. Furthermore, water content was the most important factor among influential factors as evident from multivariate analysis of soil remediation test data.