Thesis defence S. van Felz: sludge

09 December 2019 12:30 - Location: Aula, TU Delft - By: webredactie

Structural Extracellular Polymeric Substances from Aerobic Granular Sludge. Promotor 1: M.C.M. van Loosdrecht (TNW).

Biofilms are ubiquitous in hydrated environments and are an important factor in wastewater treatment and clinical applications having both positive and negative effects. They are microbial aggregates of microorganisms and surrounding extracellular polymeric substances (EPS). A novel, promising biological wastewater treatment process is the aerobic granular sludge process. In which, the microorganism form spherically shaped biofilms.

Being a novel process, little is known about the EPS composition of aerobic granular sludge. One subset of the total EPS is structural EPS. Structural EPS are involved in the integrity and stability of the sludge and have been identified as a very interesting compound. They have the ability to form ionic hydrogels, can be used a coating material to make surfaces water-repellent, and show flame-retardant properties when mixed with nanoclay platelets. An in-depth analysis of the structural EPS does not only help to better understand the matrix composition of aerobic granular sludge, but also enables an industrial application of structural EPS, promoting resource recovery from wastewater.

This study illustrates shortcomings in current biofilm EPS analysis with the examples of EPS extraction and colorimetric EPS characterization. By this encouraging the development and implementation of new analytic methods and approaches to improve future EPS analysis. New insights in the EPS of aerobic granular sludge were given in terms of chemical composition and physical properties. Structural EPS were shown to be much more complex than previously anticipated. This study helped for a better understanding of aerobic granular sludge and biofilms in general.

More information?

For access to theses by the PhD students you can have a look in TU Delft Repository, the digital storage of publications of TU Delft. Theses will be available within a few weeks after the actual thesis defence.