Environmental Effect of Co-Firing and Magnetic Field on Wood Pellets Combustion

Abstract

Trinitrotoluene (TNT), a commonly used explosive for military and industrial applications, can cause serious environmental pollution. 28-day laboratory pot experiment was carried out applying bioaugmentation using laboratory selected bacterial strains as inoculum, biostimulation with molasses and cabbage leaf extract, and phytoremediation using rye and blue fenugreek to study the effect of these treatments on TNT removal and changes in soil microbial community responsible for contaminant degradation. Chemical analyses revealed significant decreases in TNT concentrations, including reduction of some of the TNT to its amino derivates during the 28-day tests. The combination of bioaugmentation-biostimulation approach coupled with rye cultivation had the most profound effect on TNT degradation. Although plants enhanced the total microbial community abundance, blue fenugreek cultivation did not significantly affect the TNT degradation rate. The results from molecular analyses suggested the survival and elevation of the introduced bacterial strains throughout the experiment. Reference to this paper should be made as follows: Nõ lvak, H.; Truu, J.; Limane, B.; Truu, M.; Cepurnieks, G.; Bartkevičs, V.; Juhanson, J.; Muter, O. 2013. Microbial community changes in TNT spiked soil bioremediation trial using biostimulation, phytoremediation and bioaugmentation, Journal of Environmental Engineering and Landscape Management 21(3): 153Á162. http://dx.abstract. The aim of the recent research is to provide stable, controllable and effective wood pellets combustion with minimum emissions. Two possibilities were chosen, investigated and analysed: wood pellets co-firing with propanebutane mixture and the use of a permanent magnet. The special pilot device was constructed in the laboratory of Heat and Mass Transfer in Institute of Physics. Two types of experiments were conducted: combustion with propane-butane supply (0.9 kW up to 1.27 kW) of wood pellets with different moisture content (W = 8%, 15%, 20% and 25%); combustion of wood pellets with applied magnetic field by using the permanent magnet, an propane-butane supply also was used. The main conclusion of the research is that co-firing and magnetic field can be used as an instrument to provide more effective burnout of volatiles and cleaner heat production.