Thesis subject

Marcelle van der Waals

Marcelle van der Waals


1. Deltares

2. Molecular Ecology, Laboratory of Microbiology, Wageningen University



PhD candidate



2011, BS Earth Sciences, Utrecht University, Utrecht

2013, MS Environmental Hydrogeology, Utrecht University, Utrecht

2013-present, PhD student, Microbiology, Wageningen University





The increased use of renewable resources due to a foreseen scarcity of fossil fuels can potentially change the contaminants in soils and groundwater as a consequence of for example spills/leakage of biofuel storage tanks. Contamination of groundwater will often result in depletion of oxygen by aerobic microorganisms using easily degradable substrates. It is therefore important to determine and enhance degradation under anaerobic conditions.



The overall research goal of this project is to investigate the potential of bioaugmentation of microbial communities anaerobically degrading ‘potential’ contaminants of the future. Part of this research goal is to obtain knowledge about degradation (e.g. involved pathways, microorganisms) of biobased contaminants. Selected contaminants include benzene, methyl- and ethyl tert-butyl ether (MtBE/EtBE), tert-butyl alcohol (TBA) and biodiesel. Benzene is not considered as a bio-based contaminant but is a possible risk determining compound in mixtures with biofuels. We look at the influence of benzene on degradation of biobased contaminants.



In this study, microbial communities sampled from different locations in the Netherlands will be used as inoculum for laboratory experiments. Anaerobic biodegradation of benzene, MtBE/EtBE, TBA and biodiesel, and bioaugmentation with the microbial communities degrading these contaminants will be studied using microcosm cultures, continuous cultures, soil column studies, and field studies. In Fig. 1 the steps of the bioaugmentation procedure are shown. For MtBE/EtBE, TBA and biodiesel enrichment cultures will be obtained and for benzene mass is cultivated using a continuous biofilm system.

Fig. 1 Steps involved in the process of bioaugmentation