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Demonstration of Large-Scale Wastewater Ozonation at the Wastewater Treatment Plant Aachen-Soers, Germany


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According to the EU-Water Framework Directive, a "good ecological status" for waterbodies in Europe is required. 

One main premise to achieve this goal is the re-establishment of natural watercourses in order for aquatic organisms to settle. Furthermore, hydraulic stress, especially runoff from fortified areas, has to be reduced. 

Another aspect is the discharge of wastewater treatment plants (WWTPs). In the last years, the cleansing process at WWTPs has improved greatly. However, the elimination of many substances, mainly of anthropogenic origin, ist still insufficient. These substances are suspected to have an impact on the receiving water's biocenosis already at trace levels. One popular example is the presence of endocrine disruptors in waterbodies seeming to have an impact on feminisation of fish population. 

Ongoing improvements in detection methods for chemical substances illustrate the pollution of wastewater and surface waters with substances originating from households, industries and agriculture at nano range concentrations. Effects of micropollutants on the aquatic environment is subject of current research projects. One main task is the investigation of connections between the presence of micropollutants in waterbodies and their actual influence on aquatic organisms.

The elimination of micropollutants is an important element of the water sector; respective measures at a legal level can be expected. 

Ozonation and activated carbon as granulate or powder are the most common procedures for the elimination of micropollutants. However, since the substances differ strongly in their chemical properties, none of those processes is able to eliminate all substances fully. An often discussed aspect of advanced treatment steps are the associated costs. 

The Eifel-Rur Waterboard is building a large-scale ozonation plant with the purpose of evaluating its impact on the water biocenosis. The aim is to investigate whether a reduction of micropollutants can actually support the goal of "a good ecological status" in waterbodies. Therefore, a receiving water highly influenced by wastewater, the river Wurm, is subject of research within the project "DemO3AC". The Wurm consists of up to 70 % treated wastewater during dry weather periods. An extensive monitoring of both Aachen-Soers WWTP and the river Wurm is conducted before and after the implementation of ozonation. Analyses are conducted for micropollutants, microorganisms (total cell counts), antibiotic resistances, biotests and ecotoxicity as well as wastewater-related parameters.

Additionally, an optimisation of the process of ozonation on the basis of i. a. investigations conducted at the pilot-scale plant is subject of this project with the purpose of contributing to the design of large-scale ozonation plants.  

The project is funded by the Ministry for Climate Protection, Environment, Agriculture, Conservation and Consumer Protection of the State of North Rhine-Westphalia, Germany.