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.
Das Projekt "Development of economic concepts for concentrate utilisation when using membrane technology for process water/effluent treatment in paper mills" wird vom Umweltbundesamt gefördert und von Papiertechnische Stiftung München durchgeführt. The project aims at developing concepts for utilising and treating concentrates that meet environmental compatibility (meeting local and national environmental guidelines) and economical boundary conditions (limited budget of overall water treatment concept). In this context four different concentrate treatment steps are already checked or currently being checked: 1. biological treatment (aerobic and anaerobic conditions) - successfully completed, 2. ozonation (treating persistent COD compounds) - successfully completed, 3. actiflo (sand supported flocculation and flotation) - currently checked, 4. electro flotation - currently checked. Background / Problem area: Internal process water treatment is of major interest, as the loads of organic and inorganic compounds have a considerable impact on process stability and paper quality. To meet the requirements of different water consumers, membrane technology is a powerful alternative for process water treatment. However, since it is merely a separation process, it produces concentrates that have to be utilised or at worst disposed of. There is currently no application for treating or utilising accrued concentrates when using ultra filtration to obtain super clear filtrates or when using nano filtration for advanced effluent treatment. Promoting this promising membrane technology in the paper industry presupposes economically and ecologically meaningful concepts for concentrate utilisation. Objective / Research results: The project aims at developing concepts for utilising and treating concentrates that meet environmental compatibility and economical boundary conditions. Four different concentrate treatment steps have been checked: biological treatment (aerobic and anaerobic conditions) - ozonation (treating persistent COD compounds) - micro sand supported flocculation and precipitation -electro flotation. Additional process combinations based on two or three internal treatment steps have been checked. Based on the results, new ways of utilising the concentrates are considered. Different possibilities of concentrate treatment were investigated, but also options of the potentially reuse of pre-treated concentrates in the papermaking process. The results show that the micro sand supported clarification and the electro flotation is suited for reducing turbidity and the concentration of particulate matter (up to 90 percent). By electro flotation a decolouration of 50 percent was achieved however the specific costs are higher compared to the flocculation/precipitation costs. The ozonation should only be used after a biological stage. After these combined treatment steps decolouration o up to 90percentwas achieved and persistent COD was reduced as well. The concentrates could in most cases also be treated in an existing biological stage. To avoid concentration peaks in the contaminant loads, the feed of the concentrates to the biological stage should be preferable very consistent. usw.
Das Projekt "Determination of optimum operational parameters to avoid degenerated sludge microbiota in lowload aeration plants" wird vom Umweltbundesamt gefördert und von Papiertechnische Stiftung München durchgeführt. Background situation/Problem area: Approx. 96 percent of all effluents from the papermaking process are biologically treated either directly or indirectly. When existing biological waste water treatment plants are cleaned up or new ones built, they are usually equipped with multi plestages and designed to be rather spacious. The 2ndclarification step normally carries a low to very low load (BOD sludge load BTS smaller than 0,1kg/kgd). Many plant managers are forced to carry out nitrification and denitrification in the 2nd clarifying stage in order to eliminate nitrogen compounds in the light of the ever more stringent legal requirements relating to phosphorus and nitrogen. Although there are only few plant managers who are forced to carry out denitrification at the moment, the trend is clearly on the rise. Such conditions more and more frequently result in operating failures resulting in sludge degeneration leading to poor sludge settling conditions and in serious cases resulting in a violation of the legal requirements in biological waste water treatment plants in particular with multi-stage high-load/lowload plants. The importance of these problems is demonstrated by the most recent results of the PTS-VDP 'Water and Waste' inquiry, in which the most important problems in the biological treatment processes were polled. Many of the works reported malfunctions due to floating or bulking sludge, foam formation and problems in meeting discharging target values. In future, high-load/low-load plants will have to be employed to a greater extent in order to fulfil mandated requirements. The expected problems make it necessary to determine target values for the optimised operation of low-load aeration plants. Research objectives/Research results: The objective of this research project is to improve the clarification performance and ensure the stable operation of the2nd stage of low-load aeration plants. Guidelines and target values should therefore be worked out for the optimised operation of the 2nd clarifying stage of low-load aeration plants, especially for the parameters BTS, tTS, BR and O2, as wellas for the nutrient supply and elimination. Operational studies of 6 waste water treatment plants in recovered paper processing paper mills are to be conducted. Until now 4 anaerobic/aerobic activated sludge plants and 3 PSB/aerobic activated sludge plants have been investigated. Operational data of the treatment plants were evaluated over a period of minimum 3 months and additional investigations of sludge and water samples were executed. Influences of operating parameters such as sludge volume load, sludge volume index, and others on floc morphology and the quantity of filamentous bacteria were detected by the digital processing of microscopic images. All plants report at least occasional problems due to bad settling conditions of the activated sludge. usw.