This Diploma Thesis deals with the problems of applied pesticides and their active components. Pesticides are used as an agent for pest control or as a plant protectant in application areas ranging from horticulture in glass houses to the cultivation of fields in agriculture. In the year 2009, approximately 220 chemically active components as well as 33 organisms and their active components were in circulation as plant protectant in Austria. These active components and organisms are contained in 588 authorized plant protectants in Austria of which 3532 tonnes were sold in 2009. The concentrated input of pesticides on fields should assure a high crop harvest, but leads to them being introduced into various ecological material cycles. Pesticides can be found in the atmosphere, soil, groundwater as well as biosphere and exhibiting different retention times. Austria has a regulation for drinking water (BGBl. II Nr. 304/2001) with a limit value from 0,1 µg/l for every pesticide used and the corresponding metabolites formed, as well as for degradation and reaction products. The introduction of pesticides within agriculture in a community in the south of Styria has lead to increased levels for the parameters Desethylatrazine and 2,6-Dichlorbenzamid in a well which is used for drinking water. These two parameters are derivatives of herbicides that were used for plant protection. In this Diploma Thesis, possible treatment processes for drinking water are described, such as UV-disinfection, activated carbon filter, processes with membranes, processes which use ozone and finally anodic oxidation. At the spring of the concerned community, the process of anodic oxidation with diamond electrodes was used for the degradation of Desethylatrazine and 2,6-Dichlorbenzamid. Different experimental series were performed in the period July 2010 to February 2011 to reduce the parameters Desethylatrazine and 2,6-Dichlorbenzamid to below the required limit value of 0,1 µg/l. All adjustments of the experimental setups are explained and a detailed evaluation of the results is given in table and graphic form. Different laboratories analyzed the samples of the experimental series and the results were compared. This comparison includes the conventional use of gas chromatography with coupled mass spectrometry (GC-MS).