Das Projekt "Reducing the AOX concentration in the effluents of directly and indirectly discharging paper mills to comply with statutory AOX limits" wird vom Umweltbundesamt gefördert und von Papiertechnische Stiftung München durchgeführt. Initial situation/Problem area: Default Paragraph Font; Updated measures for AOX reduction suitable for all relevant paper grades in Germany are to be developed to comply with current and future AOX limits. As the final result, a simulation model will be created which enables paper mills to forecast the impact of individual measures on the AOX load of their effluents. Objectives/Research results: The new minimum requirements for the discharge of paper mill effluents define much more stringent limits, especially concerning the parameter AOX. Compared to former regulations, the specific load limits were lowered by 90 percent down to only 10 g/t for all paper grades. The most important AOX sources in paper mill effluents are: certain biocides, chlorine, chlorine dioxide for fresh or circuit water treatment, fibrous raw materials, wet strength agents based on epichlorohydrin and odour reducing compounds splitting off halogens. Due to the developments in the past decade the as-is shares of the different AOX sources have to be investigated to define actual and future measures for further AOX reduction in the effluents. Furthermore many highly loaded biological stages (anaerobic systems, moving bed biofilm reactors) have been installed in the meantime. Their potential of AOX degradation has not been investigated yet. The conventional AOX reduction by flocculation/precipitation is no longer to date or enforceable, due to economical (treatment costs of up to 2 Euro/t paper) and ecological reasons (salinisation). Especially indirectly discharging paper mills are facing severe 'AOX problems' in some cases due to the treatment of municipal effluents and are forced to minimise AOX already in their incoming flows. Application/Economic benefits: Updated measures for AOX reduction suitable for all relevant paper grades in Germany are to be developed to comply with current and future AOX limits. As the final result, a simulation model will be created which enables paper mills to forecast the impact of individual measures on the AOX load of their effluents. Anwendung/Wirtschaftliche Bedeutung: SME can save only a comparatively small amount of between 0.25 and 0.80 Euro/t on their waste water tax because this tax amounts to maximally 10 percent of their overall fees. The greater benefit of the expected results is the resulting avoidance of conventional techniques for advanced AOX elimination. Those can cause costs of up to 2 Euro/t, at higher effluent amounts even up to 5 Euro/t. Above all, the integrated approach to reducing AOX in effluents shall help to avoid these additional expenses and to safely comply with actual as well as future AOX limits.