Cavitational decontamination of unsymmetrical dimethylhydrazine waste water

• A chemical oxidant free method for decontamination of UDMH waste water is proposed.
• The method is based on induction of an advanced oxidation reaction by cavitation.
• The effects of operating parameters was investigated with the aim of optimization.
• UDMH degradation of 97.8% is obtained at the optimum conditions.
• No NDMA or any other toxic by-product was observed in the decontaminated samples.

An advanced oxidation process based on using a combination of hydrodynamic cavitation, and acoustic cavitation has been investigated for decontamination of unsymmetrical dimethylhydrazine (UDMH) waste water. The effect of various operating parameters such as velocity, inlet pressure, temperature, and pH on the extent of UDMH conversion has been studied with the aim of maximizing the extent of decontamination. It has been observed that an optimum pressure and operating temperature in a moderately acidic medium are more favorable for a rapid removal of UDMH. No toxic byproduct was observed in the decontaminated samples, although the oxidation process eliminated up to 97% of UDMH. A synergistic effect has been obtained by a hybrid method of acoustic and hydrodynamic cavitation. The total and per pass, synergistic effect achieves 16% and 68%, respectively. Due to a high optimization potential, this hybrid method can be visualized as a new step in wastewater treatment facilities involving UDMH or other refractory toxic materials.