Protocol for determining bioavailability and biodegradation kinetics of toxic organic soil pollutants to enhance in situ bioremediation

Abstract

A systematic protocol involving three types of soil reactors has been developed to quantify soil bioremediation rates. Measuring biodegradation kinetic rates in soil systems is useful in evaluating the efficacy of bioremediation and in developing accurate cost models to compare bioremediation technology with other physical/chemical treatment methods. The approach presented in this paper involves the use of three types of bioreactor systems: soil slurry, soil wafer, and soil tube reactors. Phenol was used as the test compound. The protocol was developed so that the experimental schemes which were used grew in complexity toward the actual in situ case, but remained simple enough to allow them to be adequately modeled. The data gained for each of the schemes agreed with expectations. Both the rate and extent of biodegradation of phenol were found to decrease with increasing complexity of the soil systems in the experimental schemes. Modeling procedures applied to the three experimental schemes proved useful for determining the biokinetic parameters for the degradation of phenol. Model predictions were found to agree very well with experimental data. A bioavailability index is defined which can be obtained using cumulative oxygen uptake data. The application of this protocol to other chemicals should be feasible with only minor alterations in the methodology presented in this paper.