Affiliations: State Key Laboratory of Pollution Control and Resource
Reuses, Tongji University, Shanghai 200092, China | Department of Water and Wastewater Design, Shanghai
Municipal Engineering Design Institute, Shanghai 200092, China
Abstract: The wet air oxidation (WAO) and catalytic WAO (CWAO) of the high
strength emulsifying wastewater containing nonionic surfactants have been
investigated in terms of COD and TOC removal. The WAO and homogeneous CWAO
processes were carried out at the temperature from 433 K to 513 K, with initial
oxygen pressure 1.2 MPa. It was found that homogeneous catalyst copper (Cu
(NO_3)_2) had an fairly good catalytic
activity for the WAO process, and the oxidation was catalyzed when the
temperature was higher than 473 K. Moreover, several heterogeneous catalysts
were proved to be effective for the WAO process. At the temperature 473 K,
after 2 h reaction, WAO process could achieve about 75% COD removal and 66% TOC
removal, while catalysts Cu/Al_2O_3 and
Mn-Ce/Al_2O_3 elevated the COD removal up
to 86%–89% and that of TOC up to 82%. However, complete elimination of
COD and TOC was proved to be difficult even the best non-noble catalyst was
used. Therefore, the effluent from WAO or CWAO process need to be further
disposed. The bioassay proved that the effluent from WAO process was amenable
to the biochemical method.
Keywords: catalyst, catalytic wet air oxidation, emulsifying wastewater, wet air oxidation
