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°C–420°C and the pressure range of 11–25 MPa. The results showed that after pretreatment with Ca(OH) 2 for ions removal, around 385 mg/L remained which inhibited the oxidation activity by reducing the concentration of hydroxyl radicals (•OH). Since the wastewater compounds were mainly cyclic organic materials, higher O 2 contents (stoichiometric ratio over 2.5) and temperatures (over 380°C) are favorable for TOC removal. With O 2 SR = 2.5 and T = 420°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. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 975–981, 2016