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The removal of nitroaromatics from polluted water is difficult due to their high stability to conventional treatment methods. This paper presents a method for the destruction of 1,3-dinitrobenzene and 2,4-dinitrotoluene in aqueous solutions. The compounds are shown to be stable to reaction with ozone, even under ultrasonic activation. The use of ultrasound enhances the rate of electrochemical reduction but the overall rate of reaction is still slow. However, the simultaneous application of ultrasound and ozonation to the electrochemical reaction allows virtually complete destruction of the compounds in short times. The effect is attributed to the ultrasonic enhancement of the electrochemical process giving intermediates that are susceptible to ozone oxidation. While further analytical work is needed to deduce the exact contributions of the various possible degradation mechanisms, the work demonstrates the synergies that can be gained by using combined techniques for the destruction of these difficult compounds.

In the present paper, the kinetics of the water extraction of bitumen from tar sand and crude oil or residual fuel oil from model contaminated soils under the effect of ultrasound is studied. The influence of process temperature, ultrasound power, the nature, and properties of the components of heterogeneous mixtures being separated, and the concentration of added alkaline reagents on the rate and degree of oil recovery is investigated. A functional form of the dependencies of separation efficiency on the mean size of solid particles and the temperature of a working medium is found. Optimum concentrations of reagents in the process solution are determined. It is shown that the spent solution of sodium silicate can be multiply used for separation, its reuse even speeding up the yield of oil in the initial period. Taking into account obtained results, a multipurpose pilot plant with a flow-type reactor for ultrasonic extraction of petroleum and its products from contaminated soils was manufactured and tested. During tests, the purification of sandy soil contaminated with residual fuel oil was carried out which verified the results of laboratory studies.

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