TREATMENT OF GASEOUS VOLATILE ORGANIC COMPOUNDS IN ACTIVATED SLUDGE SYSTEM

摘要

An activated sludge aeration tank (W x L x H = 40 x 40 x 300 cm) with a set of 2 mm orifice air spargers was utilized to treat gas-borne volatile organic compounds (VOCs, toluene, p-xylene, and dichloromethane) in air streams. Effects of liquid depth, aeration intensity (G/A), overall mass transfer coefficient of oxygen in clean water (K_La_(O_2)) dimensionless Henry's law coefficient of the tested VOC (H), and the influent gaseous VOC concentration (C_0) on the efficiency of the VOC removal were examined and compared with a literature-cited model. Results show that the measured VOC removal efficiencies and those predicted by the model were comparable at a G/A of 3.75-11.25 m~3 m~(-2) h~(-1) and C_0 of around 1-6 mg L~(-1). Experimental data also indicate that the reactor with K_La_(O_2)= 5-15 h~(-1) could achieve > 85% removal of VOCs with H = 0.24-0.25 at an aerated liquid depth of 1 m, and > 95% removal of dichloromethane with H = 0.13 at a liquid depth of 1 m.