Composition and biodegradability of products of wet air oxidation of polyester

Knowledge of the chemical composition of wet air oxidation (WAO) effluents is essential in determining the effectiveness of the WAO system and in selecting further treatment. WAO with excess O ₂ of cured green architectural polyester (33,77 g L ^-1 total solids) at 300 °C for 80 min gave 97% destruction of volatile solids, with 92% of the remaining total organic carbon (TOC) in the soluble form. Volatile fatty acids (C1-C5 with acetic acid as the major component) and other short organic acids (maleic and glyoxylic) and benzoic acid were also identified, in total comprising 98.5% of the soluble TOC. The polyester sample oxidized under O ₂ limitation (107.01 g L ^-1 total solids) for 4 h at 290 °C showed 84% volatile solids destruction, with 67% of the remaining TOC in the soluble form, and gave a more complex range of organic compounds. Soluble effluent from both WAO processes showed good biodegradability both aerobically and anaerobically.