Sub/supercritical water oxidation of high concentration wastewater from tall oil rosin production base

The sub/supercritical water oxidation (SCWO) of wastewater with high concentrations of pollutants from tall oil rosin production base was studied under the temperature range of 320 degrees C-420 degrees C and the pressure range of 11-25 MPa. The results showed that after pretreatment with Ca(OH)(2) for SO42- ions removal, around 385 mg/L SO42- remained which inhibited the oxidation activity by reducing the concentration of hydroxyl radicals (center dot OH). Since the wastewater compounds were mainly cyclic organic materials, higher O-2 contents (stoichiometric ratio over 2.5) and temperatures (over 380 degrees C) are favorable for TOC removal. With O-2 SR=2.5 and T=420 degrees C, the TOC removal reached almost 100% (99.89%) in 30 min. A global kinetic model for TOC removal during SCWO treatment was built during the research. The kinetic data acquired through the model were fitted to a power-law function, and the data correlated well with the experimental data. (c) 2016 American Institute of Chemical Engineers Environ Prog, 35: 975-981, 2016