Organic wastewater treatment by using superheated and near-critical water oxidation
ZHAO Guangming1, LIU Yucun1, CHAI Tao1, WANG Hongwei1, TIAN Jiangxia2
1. School of Chemical and Environmental Engineering, North University of China, Taiyuan 030051, China;
2. Shanxi Tianhegaoqing Technology Co., Ltd., Taiyuan 030051, China
Abstract:In this paper, the feasibility of waste water oxidation treatment in superheated near-critical region of water is studied through experiments. Five kinds of typical industrial organic wastewater which are difficult to biodegrade are chosen for purification experiments. They are coking wastewater, penicillin wastewater, papermaking wastewater, acrylonitrile wastewater and TNT wastewater, respectively. The temperature of the experiment is 420-530℃ and the pressure 21-26 MPa. The results show that at a constant pressure the CODcr removal ratios of the five kinds of wastewater are increasing rapidly with temperature increase,whereas at a constant temperature the CODcr removal ratios are only slightly increased as the pressure increases. Additionally, the differences of CODcr removal rates and purification rate of water in the outlet of the system at different pressures are gradually reduced as the temperature increases. Under conditions of temperature at 520-530℃ and pressure at 21 MPa, the purified CODcr values of the five typical kinds of wastewater are less than 200 mg/L, even less than 100 mg/L. Through a technological and economic analysis, it is pointed out that considering the engineering practice, the superheated and near-critical water oxidation is more suitable for industrial organic wastewater treatment, instead of the supercritical water oxidation technology.
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