Effect of pine bark on the biotransformation of trinitrotoluene and on the bacterial community structure in a batch experiment

Abstract

Pine bark, a low-cost industrial residue, has been suggested as a promising substitute for granular activated carbon in the on-site treatment of water contaminated with 2,4,6-trinitrotoluene (TNT). However, the complex organic structure and indigenous microbial community of pine bark have thus far not been thoroughly described in the context of TNT-contaminated water treatment. This two-week batch study examined the removal efficiency ofTNT from water by (1) adsorption on pine bark and (2) simultaneous adsorption on pine bark and biotransformation by specialized TNT-biotransforming microbial inocula. The bacterial community composition of experimental batches, inocula and pine bark, was profiled by Illumina sequencing of the V6 region of the 16S rRNA gene. The results revealed that the inocula and experimental batches were dominated by phylotypes belonging to the Enterobacteriaceae family and that the tested inocula had good potential for TNT biotransformation. The type of applied inocula had the most profound effect on the TNT-transforming bacterial community structure in the experimental batches. The indigenous microbial community of pine bark harboured phylotypes that also have a potential to degrade TNT. Altogether, the combination of a specialized inoculum and pine bark proved to be the most efficient treatment option for TNT-contaminated water.

Biotransformation of pink water TNT on the surface of a low-cost adsorbent pine bark

“…1). The biotransformation pathway is described in greater detail elsewhere (Chusova et al 2014). The respective mass balance calculations are presented in Supplementary Table 2.…”

“…The results of a previous study by Chusova et al (2014) indicated that in addition to its adsorptive capacity, pine bark also harbors bacterial groups capable of survival and growth in the presence of TNT water solution. TNTladen pine bark, contrary to activated carbon, can either be composted on-site or co-digested with other, more easily degradable substrates for methane production.…”

Application of FT-IR Spectroscopy for Investigation of Pink Water Remediation by Pine Bark

“…The first culture, subsequently referred to as In1, co-metabolised TNT (0.4 mM), while the second culture, referred to as In2, co-metabolised the previously described TNT-contaminated industrial sludge mixed with water (1.5 -2.0% v/v). The cultures were transferred weekly into fresh mineral salt medium M9* [8] containing glucose and TNT in the case of In1 and glucose and sludge particles in the case of In2.…”

“…This adsorbent has also been studied for the removal of organic pollutants such as PAHs [4], bisphenol [5], estradiol (E2) [6] and lindane [7] from contaminated water. Chusova et al [8] showed that pine bark can effectively remove TNT from pink water, a wastewater generated during the process of demilitarization of explosives at army ammunition plants.…”

“…Our previous research [8] showed that biotransformation of TNT in the presence of pine bark has potential as a possible substitute for conventional granular activated carbon treatment of pink water. However, additional research is needed to evaluate the economic feasibility of pine bark for the treatment of pink water, its affinity toward compounds other than TNT constituents and the necessity of pine bark pre-treatment to enable higher treatment efficiency and safety.…”