Microsoft word - a8.doc

New European demands as a challenge to develop new
technologies for the removal of micropollutants in
wastewater
Environmental Technology University of Dortmund Emil-Figge-Str. 70 D-44221 Dortmund Phone: +49 231 755 2322 Fax: Abstract
With the European Water Framework Directive (EU-WRRL) [1], which came into force on the 22nd Dec. 2000, the transfrontier water policy in Europe began. The federal water act in Germany (WHG) was changed accordingly on the 25th June 2002. With this the water resources policy started and the way for European river basin management was levelled out. The essential aim of the guidelines is to obtain an effective ecological water management with high standards. This means for surface waters to reach a good chemical and a good ecological condition within 15 years after the guideline was brought into force. Attachment X of the EU-WRRL contains a list with prioritized and prioritized dangerous water pollutants. Based on common European right binding agreements should be worked out to restrict the entry of water pollutants and detectable Prioritized Pollutants are persistent, toxic and have bio-accumulative characteristics. For these pollutants the discharge, the emissions and the losses into surface water are to be decreased step by step. There is also a quest that a common agreement is found for quality specifications and emission restrictions. In contrast the prioritized dangerous pollutants bare additional long-term risks due to irreversible accumulation of biological-active organic-synthetic substances in organisms and environmental systems. The intention is to end or gradually reduce the discharges, emissions and losses within the next 20 years after approbation of the European parliament and council [2]. Next to the already named pollutant in the attachment X of the EU-WRRL there are other water relevant substances. Because of the amount that is released into the aquatic environment and the finally not determined capability of polluting surface waters the current discussions are still carrying on. The main emitters of water pollutants (see Fig 1) are the municipal wastewater treatment plants and the stormwater flow as well as the diffuse resources and WWTP outflow
dischrage system
WWTP outflow 2
discharge system
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Generally there are different methods to remove water pollutants such as organic and inorganic particles including soluble matter. The different techniques are based on mechanical, chemical, biological and physical methods. In detail the sedimentation, filtration, precipitation and flocculation are mentioned as well as membrane-filtration (mikro-, nano- and ultra-filtration, reverse-osmoses), adsorption with activated carbon and chemical-oxidative processes (see Fig 2). For environmental compliance these methods can also be combined. Whereas most of these methods only separate the harmful substances from the water, the oxidative process causes degradation of the micro-pollutants. These are removed out of the water by conversion, so that no other treatment is needed. The modern municipal wastewater treatment plants are designed to eliminate carbon, nitrogen and phosphate by means of biological and chemical treatment. The customary process engineering is an aeration system that is in some cases connected with a supplementing filtration plant. Fig 2 – further technologies for the removal of water-impurities [3] In one of the research projects, which have been promoted by the office of environment and nature conservancy, agriculture and consumerism (German abbr.: MUNLV), a definite elimination of pollutants was noticeable in the different processing steps on a wastewater treatment plant. On the other hand other pollutants pass through the plant without being eliminated in an appreciable The total productivities of two big wastewater treatment plants have been balanced as well as the elimination paths of the different treatments have been investigated. In an accompanied experimental research on a semi-technical plant the influence of various operating parameters was determined. The focus of the examination was the sludge age, the concentration of the solid matter, the usage of coagulant to eliminate phosphate and the applied bio-membrane reactors. Only by varying the operating parameters, a satisfying degradation for the most of the trace-elements could not be guarantied. Therefore it seems that the wastewater treatment plant needs to be upgraded with a still to be determined tail-end- technology for the proceeding wastewater treatment. This middle-term economical solution is preferable to a deeper restructuring of the already existing configuration of the plants. Possible alternative for the advanced wastewater treatment can either be oxidation or adsorptive procedures. Acknowledgement
This study was part of the NRW-Project “Untersuchungen zum Eintrag und zur Elimination von gefährlichen Stoffen in kommunalen Kläranlagen”, which was financially supported by the ministry for the environment and nature conservation, agriculture and consumer protection of Nordrhein-Westfalen, Germany. References
[1] Richtlinie 2000/60/EG des Europäischen Parlaments und des Rates zur Schaffung eines Ordnungsrahmens für Maßnahmen der Gemeinschaft im Bereich der Abwasserpolitik, 2000 [2] www.wrrl-info.de/docs/VeltwischWRRL.pdf Untersuchungen zur oxidativen Eliminierung organischer Wasserschadstoffe, Dissertation, Fraunhofer Institut für Umwelt-, Sicherheits- und Energietechnik UMSICHT, Oberhausen, 1998

Source: http://www.envirowater.de/Programme/A8.pdf