Analysis of Effluent Characteristics of Bio-treated Pulping Wastewater (BTPW) during Ozonation

The effluent of a pulp mill was subjected to a biological treatment followed by ozonation to study the potential biodegradability improvement of recalcitrant compounds. Characteristics of the bio-treated pulp wastewater (BTPW) before and after the ozonation process were analysed by Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, gel permeation chromatography, and gas chromatography, which detected the variations in the organic compounds in the effluents. Results showed that the ozonation treatment has the potential to turn some refractory compounds into biodegradable compounds and therefore increase the biodegradability of the BTPW. The increased biodegradability was accomplished because ozonation affects the structure of the refractory compounds and degrades the macromolecular organic matter into micromolecular organic matter. Furthermore, it is proposed that the degradation of macromolecular organic matter happens fast and therefore there are structural changes, since smaller molecules are formed. Then, these smaller molecules degrade over a longer period.