Period
June 2013 to Oktober 2015
Description
A whole zoo of organic compounds which differ in their chemical, physical and biological characteristics can be found in water. These compounds either are geogenic and/or anthropogenic. The natural occurring substances are present as a result of chemical and microbiological degradation of plant material and from dissolution of soil-derived material. The term natural organic matter (NOM) or humic substances (HS) is used to describe this complex mixture of organic substances originating from natural sources, and they are present in all water bodies. Their concentrations lay in the mg/L-range (determined as mg/L DOC; dissolved organic carbon). In the drinking water ordinance the parameter TOC (total organic carbon) is listed as an indicator parameter.
Since several years many raw waters (rivers, lakes, groundwater, reservoir water) used for drinking water show a steady increase in the TOC (DOC) concentration. Although NOM is essentially not toxic, increasing TOC or DOC concentration might lead to problems in the treatment process during flocculation, adsorption, oxidation and disinfection steps. As a result, problems with increasing regrowth potential, increasing disinfection by-products formation, increased solubility of heavy metals due to complexation with organic matter could arise. In addition, the color, taste and odor of the water may be negatively affected.
The parameters TOC and/or DOC can be analyzed with high precision. However, a further characterization of the properties of the organic matter is not given. This holds also for the data produced by spectroscopic methods working in the UV and visible range.
For an advanced characterization of the quality of the organic matter, liquid chromatographic separation can be used in combination with online DOC-, UV- and fluorescence detection. Especially size-exclusion has turned out to be useful for an assessment of the dissolved organic matter (DOM) and its behavior in water treatment processes.
The project aims for the advanced characterization of different raw waters used for drinking water production, and the characterization of the changes in the DOC quality during the different treatment steps.
