Increasing the biodegradability of rocket fuel polluted groundwater by means of chemical oxidation processes

Highly toxic residues of rocket fuel have been detected in the groundwater of an abandoned military missile base in north-west Estonia. The growth of indigenous rocket fuel- degrading bacteria in the polluted groundwater is strongly inhibited by a high concentration of pollutants in the groundwater. Two chemical oxidation processes, ozonation and catalytic wet oxidation (CWO), were studied for the treatment of such groundwater. The ozonation experiments were carried out in a wetted-wall column and the CWO experiments were conducted in an autoclave in the presence of granulated activated carbon. The ozone-water contact column operated at laboratory temperature whilst in CWO the operational variables ranged as follows: temperature from 413 to 446 K, oxygen pressure from 0.4 to 1 MPa. Both processes degraded the primary rocket fuel pollutant (dimethylanilines) and increased biodegradability. The solution remaining after ozonation and CWO contained mainly organic acids. Despite the formation of refractory compounds, the residual water can be treated in bioprocesses without complications b ecause organic acids are easily biodegradable.