Bioremediation of TNT Contaminated Soil by Composting with Municipal Solid Wastes

In recent years, a number of biological processes have been used for bioremediation of TNT contaminated soils. The goal of this research was to select the proper formulation of the compost materials based on mechanically sorted organic fraction of municipal solid wastes (MSW) that can provide the proper balance of carbon and nitrogen and the best conditions to promote biological activity in the compost and to reach the highest TNT removal. Seven factors, including TNT contaminated soil (%w/w), trace element solution (%v/w), chicken manure (%w/w), TNT concentration (mg/Kg), microbial suspension (%v/w) of isolated and selected microorganisms from TNT contaminated sites, cow manure (%w/w), and composting condition (aerobic and anaerobic) were considered using Taguchi statistical methods. L8 and L9 orthogonal arrays and analysis of variance (ANOVA) were applied to assess the most significant factors affecting the TNT removal. The optimum conditions to maximize TNT removal were aerobic condition, 35% (w/w) TNT contaminated soil, 5% (w/w) cow manure, 5% (v/w) microbial suspension and 50000 (mg/Kg) TNT concentration. In optimum conditions, TNT removal of 99.99% was obtained within 15 days, which is a relatively short time when compared with previous studies. The very high organic contents (over 70%) of municipal solid wastes in Iran provide ample raw materials for production of compost to treat contaminated soils.