Modeling of Landfarming for Remediation of Contaminated Soils and Sediments

摘要

With bioremediation using landfarming, a large part of biodegradable contaminants in soils and sediments are biodegraded rapidly, but a residual concentration remains. This residual concentration is shown to be degraded slowly, and a portion degrades very slowly. Treatment on a passive landfarm, where input of labor and energy are restricted as much as possible, gives sufficient results. In passive landfarms three potentially limiting factors can be identified: (1) availability of appropriate microorganisms, (2) supply of oxygen for the biodegradation process, and (3) bioavailability of the pollutants to the microorganisms. Degradation of PAHs and mineral oil can be described using a multicompartment model, in which three degradable fractions are distinguished: (1) rapidly, (2) slowly, and (3) very slowly degradable. Using this model filled with data from long-term field experiments (started in 1990), it can be predicted whether years or decades will be necessary to clean the soil or sediment to a point at which it is fully reusable. Less time is necessary if risks are considered.