PAPER making! g! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ® Volume 12, Number 1, 2026
processes (AOPs) are promising for the advanced treatment of secondary effluent from pulp and paper wastewater (SEPP). However, chloride ion (Cl - ) in such matrices readily promotes chlorine species formation during oxidation. Current engineering practice remains largely removal-focused, often neglecting associated ecological risks. To address this gap, a multidimensional evaluation framework was established to compare four representative AOPs applied to a single SEPP matrix. Fenton, ozonation and catalytic ozonation exhibited stronger oxidative capacity towards organic pollutants, whereas electrochemical oxidation (EO) achieved superior removal of total nitrogen and ammonia nitrogen. Distinct reaction mechanisms led to markedly different chlorine species formation: under the tested conditions, active inorganic chlorine species (AICS) in EO effluent reached 168mg-Cl/L, two orders of magnitude higher than those in ozonation and catalytic ozonation. EO yielded the highest concentrations and greatest diversity of chlorinated organic products (COPs). Acute toxicity, assessed before and after oxidants quenching, consistently followed EO > Fenton > ozonation > catalytic ozonation. Free chlorine was identified as the primary contributor to AICS-related toxicity, while dichloroacetic acid dominated the overall toxicity attributable to COPs. Comprehensive evaluation identified catalytic ozonation as achieving a more favorable balance between removal efficiency and toxicity under the tested SEPP matrix and engineering-relevant operating conditions. These findings emphasize the necessity of reconciling removal objectives with the mitigation of chlorine species generation in AOPs implementation and provide comparative and scenario-specific quantitative insights to inform the selection of AOPs for SEPP treatment. “Evaluation of the detoxification effect and toxicity mechanism of Fenton process for pulping wastewater treatment”, Fei Di, Donghui Han, Jinquan Wan, Guang Wang, Yan Wang, Journal of Water Process Engineering , Vol.70, Feb. 2025, 107041. Fenton process, an advanced treatment technology, has been extensively applied to optimize the discharge quality of pulping wastewater. However, the regulation of wastewater toxicity is still in its infancy, with underlying toxicity mechanism remain unclear. This study systematically evaluated the detoxification performance of Fenton process through acute and chronic toxicity tests. Toxic pollutants were traced by a combination of toxicity identification evaluation (TIE) and non-targeted screening, while the toxicological priority index (ToxPi) was employed to elucidate the toxicity mechanism. Although Fenton process reduced the pollution load, it increased the toxicity unit (TU) toward luminescent bacteria and Daphnia magna from 2.76 and 0.33 to 5.12 and 0.84, respectively, and induced irreversible oxidative damage to organisms. TIE analysis revealed a significant reduction in acute toxicity (56.99%) following the shielding of organic pollutants. Non-target screening detected newly pollutants (e.g., Trihexyl phosphate) and elevated peaks of existing pollutants. ToxPi identified Trihexyl phosphate, Dihexyl phthalate, and Dinonyl phthalate as priority toxic pollutant. These findings suggest that the transformation and generation of toxic organic pollutants suppress the detoxification efficiency of Fenton process. In conclusion, the present study highlights the limitation of Fenton process for toxicity control, provides comprehensive insights into the toxicity mechanism, and offers valuable guidance for optimizing wastewater treatment and discharge regulation. WOOD PANEL “The effect of structural characteristics on the properties of oriented strand board”, Wanzhao Li, Cheng Yang, Pingping Hong, Tao Chen, Changtong Mei & Junfeng Wang, European Journal of Wood and Wood Products , Vol.84, article number 31, (2026). Oriented strand board (OSB) is an important engineered wood product. The physical and mechanical properties of OSB can be adjusted by optimizing its structural characteristics to fulfill the different application fields. Eight types of boards were produced in the lab in terms
Technical Abstracts
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