Benchmarking sustainability in tissue manufacturing: Evaluating bleaching and effluent treatment practices

The production of tissue article from recovered fibers is associated with significant environmental challenges arising from both raw material quality and the intensity of treatment processes. In contrast to many studies in the literature that focus primarily on compliance with emission limit values or the analysis of single parameters, this study proposes a benchmarking approach based on normalized performance indicators referenced to unit production (kg ADt^-1, kg t^-1) and encompassing the entire upstream-downstream chain. The analytical framework developed integrates key environmental indicators-water and energy consumption, emissions to water (chemical oxygen demand, adsorbable organic halogens), and sludge generation-thereby enabling a comprehensive, system-oriented assessment consistent with the Best Available Techniques Reference Document (BAT/BREF) framework and CEPI recommendations. The analysis of four case studies demonstrates that the investigated plants operate within CEPI reference ranges; however, the dispersion of key performance indicators reveals considerable scope for further optimization. The results indicate that upstream factors, including bleaching intensity and recovered fiber quality, exert a stronger influence on total pollutant loads and sludge generation than effluent concentrations alone. Downstream treatment processes achieve comparable pollutant removal efficiencies; however, the associated environmental costs, in terms of energy and chemical consumption, are strongly dependent on wastewater characteristic. The findings also confirm the presence of cross-media effects, whereby reductions in emissions to water may lead to increased sludge production or higher energy demand, thereby underscoring the need for integrated, system-level optimization.