Effect of co-substrate on anaerobic slurry phase bioremediation of TNT-contaminated soil

Abstract

Molasses and starch were used to estimate the effect of co-substrate on anaerobic slurry phase bioremediation of TNT (2,4,6-trinitrotoluene)-contaminated soil. Degradation efficiency of TNT in molasses and starch addition was approximately 97% and 87%, which is 50-60% higher than 38% without co-substrate addition. Molasses and starch addition enhanced TNT degradation. It was proved that the TNT degradation was a mainly biological process from the result of an abiotic control experiment. In case of molasses addition, overall first order degradation rate was 0.0161/ day indicating the most active TNT degradation. The first order degradation rates (k 1 =0.0056 for molasses, k 1 =0.0033/ day for starch) before 60 days were slower than those thereafter (k 2 =0.0237 for molasses, k 2 =0.0136/day for starch). Lower degradation rate in early stage might be due to adaptation of native soil microorganisms.

Statistical factor-screening and optimization in slurry phase bioremediation of 2,4,6-trinitrotoluene contaminated soil

“…This includes supplemental carbon and nitrogen sources [31][32][33][34][35], microorganism [36], pH and temperature [32,36] in aqueous phase as well as slurry concentration, agitation speed [28] and surfactant [29,37] in slurry phase. Nevertheless, a one at a time approach was used to look at the effect of each factor in slurry phase and therefore the possible interactions among the effective factors have not yet been assessed.…”

“…Previous studies have shown that carbon and nitrogen sources are essential for TNT metabolism [31][32][33][34][35] since cultures deficient in these two sources could not grow [31]. Boopathy et al [31] and Kalafut et al [35] have shown that NH 4 Cl can serve as a suitable nitrogen source in aqueous phase.…”

Anaerobic biodegradation of DDT in contaminated soil by biostimulation: laboratory and pilot-scale studies

“…In treatments T4 and T5, 1.5 g of KNO 3 was added as a nitrogen source and electron acceptor. Molasses was applied in the treatments T3 and T4 in single-doses at the start of the experiment (In et al 2008). These experiments were conducted for 30 days and the concentrations of DDT were measured (USEPA SW-846 2007; USEPA SW-846 1996a; USEPA SW-846 1996b) at the beginning and end of each treatment.…”

Sustainable remediation – The application of bioremediated soil for use in the degradation of TNT chips

“…Studies have shown that TNT is susceptible to biotransformation under aerobic and anaerobic conditions (Esteve-Nunez et al, 2001;In et al, 2008). This susceptibility to biological (microbial) degradation can be exploited for decontamination purposes.…”