Microbially-Mediated Decontamination of CBRN Agents on Land and Infrastructure Using Biocementation

摘要

Physical, and chemical decontamination of CBRN-polluted land and infrastructure must be carried out following the military actions, industrial accidents, or terrorist attacks. This can be done by adsorption, chelation, ion exchange, degradation, or immobilization of CBRN agents and due to the coating or clogging of upper layer of soil or debris material. Biotechnological decontamination of land and infrastructure, as well as dust and leaching control of soil and demolition debris is an innovative approach, which is more acceptable in some cases than any other methods of decontamination due to its environmental safety, lower cost, and deep penetration of decontamination solution in soil. Dispersion of CBRN agents in environment with dust or leachate from the soil or debris surfaces can be decreased using such bioprocesses as microbially mediated ion exchange, adsorption, aggregation, chelation, precipitation, clogging of the pores, biocementation, biocoating, bioimmobilization, biochemical oxidation and degradation. Major processes of decontamination are as follows: (1) biocementation/biocoating of surface due to formation of calcium carbonate activated by enzyme urease hydrolyzing urea; (2) immobilization of CBRN agents due to formation of calcium carbonate during aerobic microbial degradation of calcium formate or acetate; (3) enzymatic or microbially-mediated formation of calcium phosphate biocement. Experiments with biocementation showed that more than 95% of chemical or bacteriological pollutants can be fixed in upper soil layer and do not dispersed in environment with dust or surface water flow. These technologies are feasible in the field conditions. However, a problem of this technology is brittleness of biocement, which can be solved using nanostructure composition of biocement with elastic nanocomponent modeling natural bone or other organic biominerals.