Characteristics of TOC Treatment for Industrial Wastewater Treatment - Characteristics of Industrial Wastewater TOC Treatment Status and TOC Treatment by Ozone and Advanced Oxidation Process -

Abstract

Purpose: As the organic pollutant indicator is changed from CODMn to TOC and the demand for TOC treatment of industrial wastewater increasing, the current situation of TOC treatment of wastewater discharge facilities of each industrial category is analyzed, and it is intended to consider the possibility of residual TOC treatment by ozone and advanced oxidation process. Method: To review the TOC treatment situations of wastewater discharge facilities of each industrial category, the field survey data (46 sites) by Environment Ministry and Korea Environment Corporation were analyzed according to inflow TOC concentrations, direct/indirect discharge type, and main treatment process of wastewater treatment facilities. To review the characteristics of TOC treatment by ozone and advanced oxidation processes, previous studies and the results of field pilot tests conducted by ozone companies were comprehensively analyzed. Results and Conclusions: The TOC treatment level varies depending on the inflow TOC concentrations to each industrial wastewater treatment facility, direct/indirect discharge type depending on the location of the wastewater treatment facilities, and the main treatment process of the wastewater treatment facility. In particular, the TOC removal rate differed by more than 20% depending on the presence or absence of biological treatment. The wastewater treatment facilities that require additional treatment of residual TOC were divided as follows (1) when the facility has biological treatment as main process, increasing unexpected inflow TOC load in treatment facilities or the condition of the biological treatment become worsen. (2) when the facility has phy-chemical treatment as main process, increasing unexpected inflow TOC load. (3) extending the replacement cycle of activated carbon to save maintenance cost. Therefore, for additional TOC treatment, it is necessary to secure the stability of the main process in preparation for load fluctuations and to apply post TOC processing suitable for the characteristics of the main treatment process. The direct oxidation reaction of ozone forms intermediate products such as carbonyl groups and carboxyl groups and hydrogen ablation are difficult to convert to inorganic carbon, and the advance oxidation process decomposes easily by OH radicals through the radical substitution of unsaturated hydrocarbons and aromatic compounds, so the removal rate of TOC by the O3+H2O2 advanced oxidation pilot test was 14.7∼93.5%, higher than that of ozone oxidation. The specific ozone consumption per TOC removal amount (O3/ΔTOC) by O3+H2O2 advanced oxidation is 8.5~22.5mgO3/mgTOC, which is 1/5 of that of ozone oxidation, so the advanced oxidation process is suitable for removing residual TOC of industrial refractory wastewater. In addition, comparing ozone consumptions by ozone & O3+H2O2 advanced oxidation to remove CODMn and TOC, ozone consumption of O3+H2O2 advanced oxidation to remove TOC is 2.7 to 4.3 times compared to that by O3 oxidation to remove CODMn and ozone consumption of ozone oxidation to remove TOC increased by 13.3 to 21 times than that by O3 oxidation to remove CODMn. Therefore, when introducing the TOC additional treatment process the different treatment characteristics of CODMn and TOC should be considered.

Keywords

• total organic carbon (toc)
• o3
• o3+h2o2
• aop
• industrial wastewater treatment