Effluent organic matter removal during advanced wastewater treatment process: O3-BAC and AC/O3-BAC

The performance of O₃-BAC and AC/O₃-BAC processes was investigated for treating effluent organic matter (EfOM) from biologically treated sewage effluent (BTSE). It was found that DOC removal efficiency was 40% during steady stage of operation, with an ozone dose of 2.5~3.5mg/L and contacting time of 24min. DOC removal was mainly happened in the activated carbon filtration step, while the decrease of SUVA, which represents the aromaticity of organic materials, was accomplished primarily in the oxidation step. Comparing with O₃-BAC, AC/O₃-BAC decreased the effluent DOC and increased the aromaticity of effluent. Coagulation, sedimentation and sand filtration can remove a fraction of large molecular weight (MW) organic materials and only slightly decreased the DOC. Oxidation decreased the content of protein and tannin, and consequently influenced the constitution of dissolve organic matter. It was found that organic materials with MW in the range of 100Da-2000Da can be effectively removed after O₃ or AC/O₃ oxidation. This fractions as well as little MW organic materials that were generated during oxidation processes can be further removed by biological activated carbon (BAC) filter. Soluble microbial products were the main constitute of BAC effluent.