Removal of organic matters in pesticide wastewater by supercritical water oxidation

摘要

Supercritical water oxidation (SCWO) is an alternative to effectively dispose many varieties of organic wastewaters. In this article, a high concentration pesticide wastewater with very complicated components was handled hy SCWO in a batch experimental plant at 25 MPa, 410-580 °C within the oxidant coefficient of 1.1-4.0 and the residence time of 1.0-10.0 min. The results show that reaction temperature, oxidant coefficient, residence time can improve XCOD (removal efficients of chemical oxygen demand) of reactor effluent. X_(COD) reaches up to 99.89% at 550 °C, 25 MPa with the oxidant coefficient of 3.0 and the residence time of 5.0 min, and the corresponding COD concentration is 73 mg/L. Residence time indicates a relatively more important influence on COD, at higher reaction temperatures and OCs. Furthermore, possible reaction pathways for SCWO of organic matters in the pesticide wastewater were also proposed primarily.