Assessing and minimizing the leakage of powdered activated carbon from wastewater treatment processes for micropollutant removal

To prevent the emission of potentially harmful anthropogenic micropollutants into rivers and lakes, an increasing number of wastewater treatment plants is currently being equipped with advanced water treatment processes. When applying micropollutant adsorption onto powdered activated carbon (PAC), an efficient separation of PAC particles is crucial to prevent PAC leakage into the receiving water body. In this thesis, the separation of PAC in advanced wastewater treatment processes is studied. In the frame of a detailed literature research, the state of the art in solids separation in PAC processes is determined and practical recommendations are made. As a basis for further studies, a thermogravimetric method for sensitive and quantitative detection of low PAC concentrations in wastewater samples is developed. By successively heating solid samples under nitrogen and oxygen atmospheres, it allows for the quantification of PAC in mixed solid samples. Using this method, the PAC separation in a large-scale deep bed filter is examined. The focus is on the dynamic behavior of solids retention, headloss and micropollutant separation efficiency in the course of a filtration cycle. The experiments show a very good solids retention and it is found that PAC in particular is separated more efficiently than other solids. To minimize the load of PAC particles sized