2. Degradation of personal care products in wastewater treatment plants
Which bacteria are responsible ? How can we increase their activity ?
There is a growing concern about both the ecological and toxicological
effects of pharmaceuticals and personal care products (PPCP) present in
our waterways. Even if these pollutants are present in minute amounts
there is a worry that a mixture of many different synthetic compounds
might have synergistic effect. The major source of PPCP is human use and
household waste. Generally, wastewater treatment plants (WWTP) are
equipped to handle organic matter and nutrients, but not necessarily
PCPPs. The result is that they are released into in our lakes and
oceans. One such substance is Diclofenac (DCF), a commonly used
non-steroidal anti-inflammatory drug. Due to the relative poor
degradation in in WWTPs diclofenac has been found in WWTP effluents and
receiving rivers and it has recently been added to the watch list of
substances (EU 2013).
The degradation potential and the degradation pathways of diclofenac are still uncertain and there are widely varying results from different systems. This might be because the conditions for degradation are not optimal in the wastewater treatment plants and/or that the microorganisms (Bacteria or Archaea) are simply not present/active.
In WWTPs, microorganisms are the main drivers for nutrient and organic matter degradation. Several studies have suggested that there is a “core microbial community “ present in WWTP even in different geographic locations and different operational setups. However recent next generation sequencing (NGS) techniques have revealed a great diversity of microorganisms in WWTPs, with some “rare” species not being a part of this “core microbial community”. One unanswered question is whether diclofenac degrading bacteria is part of the “core” species or not. The high variability in degradation from different studies may suggest they are not.
The overall objective is to find ways to increase degradation of PCPPs in WWTPs, thus decreasing the efflux of these compounds to the environment. We use diclofenac as a model compound.
To do this our
goals are to identify the microorganisms / microbial population that
best degrade diclofenac. One would then be able to
1) assess the potential for degradation based upon the microbial population
2) find possible was of stimulating the growth /activity of the degrading microorganisms / microbial population.