Effect-directed analysis and NTS for the evaluation of drinking water production processes

Schematic structure of the KOLa System (continuous ozonation with slow sand filtration) (left); Effect-related investigation of spiked drinking water from Karlsruhe according to different enrichment methods (right) (Image: TZW und ZV Landeswasserversorgung /L. Betz)

The WBA-NTS-ProTrink project is intended to further develop the approach developed in a previous project of using effect-ditected analysis in combination with chemical analyses to assess organic micropollutants.

Given the large number of often unknown organic micropollutants, the process evaluation in drinking water production can no longer be carried out using target analysis alone. Therefore, innovative approaches such as the combination of effect-directed analysis (EDA) and non-target screening (NTS) are needed to systematically investigate and evaluate the behavior of trace substances in drinking water production. of trace substances in drinking water production.

The following sub-goals are targeted:

  • Relevant treatment steps in drinking water production are to be characterized by WBA and in parallel by means of NTS, and a combined WBA-NTS assessment index is to be derived. This should also be validated under extreme conditions such as heavy rainfall or drought.
  • For typical treatment steps in drinking water production such as bank filtration, disinfection, etc., an "effect index" will be developed that ranks the processes according to their performance in removing effects. This is to be related to results of an NTS process description.
  • Data evaluation is to be further standardized with the incorporation of Toxic equivalent concentrations (TEQs).
  • Since an optimization of treatment processes during the operation of waterworks cannot fully realized, it is necessary to have a test plant for the reproduction of different treatment processes and their combinations available. Therefore, with the help of a laboratory plant, particularly relevant process parameters for different treatment processes and their combinations are to be identified and optimized. 
  • Within the framework of a feasibility study, it will be examined whether an extension of the test end points with relevance to human toxicology is possible. For this reason, it will be investigated whether in vitro bioassays based on human cell lines, which better reflect the cellular metabolism of humans, can be integrated into the existing EDA concept.
  • Since the results of EDA and NTS differ substantially from those of target analysis (effect for a particular test endpoint vs. concentration), the project will develop a standardized form for the interpretation and communication of EDA results.

To characterize individual treatment steps, TZW will operate a laboratory-scale treatment plant with a modular design that can be adapted to the various treatment stages of real waterworks, e.g. ozonation followed by activated carbon filtration, chlorination or UV disinfection. This makes it possible to identify processes and parameters relevant for process optimization with regard to maximum reduction of effects or substance concentration.