Dissolved Organic Matter Dosing To Enhance In Situ Micropollutants Biodegradation In Drinking Water Aquifers

Almost two thirds of the drinking water in the Netherlands comes from groundwater. Recent studies have detected micropollutants such as pesticides and pharmaceuticals in Dutch groundwater, sometimes in concentrations close to or above the permitted level (0.1 µg/L for a single micropollutant).

Biodegradation of micropollutants can occur naturally in the environment and it can be influenced by the presence of dissolved organic matter (DOM). In groundwater, DOM is present at low concentrations and is very recalcitrant, which
leads to low rates of this natural attenuation. However, previous research indicates that amendment with a labile DOM source can enhance the biodegradation of micropollutants.

Hence, the aim of this research is to study the effect of DOM dosing in order to develop an in situ micropollutants bioremediation technology in groundwater.

Technological challenge

When developing an in situ micropollutants technology some challenges need to be overcome. The low concentrations of micropollutants (µg/L range or lower) can be hamper to biodegrade and DOM can be preferentially degraded over micropollutants. Furthermore, for micropollutants degradation to occur, favorable environmental conditions are required but groundwater conditions (e.g. low microorganism density, anaerobic environment and low temperature) do not support biological activity. Finally, the in situ treatment should not affect the quality of groundwater as it is used for drinking water production.

Research goals

This project is divided in 4 phases:

Phase 1 – Screening for biomass sources capable of degrading micropollutants and assess the effect of different DOM sources on micropollutant biodegradation

Phase 2 – Understand the kinetics and mechanisms of degradation at conditions mimicking the aquifer (column experiments)

Phase 3 – Develop a groundwater transport model that includes the biological degradation processes

Phase 4 – Perform a field demonstration of the developed in situ micropollutants bioremediation technology

Micropollutant attenuation in groundwater: A – Natural attenuation; B – DOM amended attenuation
Micropollutant attenuation in groundwater: A – Natural attenuation; B – DOM amended attenuation