Catalan Water Research Institute research and innovation for the sustainable use of water


01/06/2020 - 31/12/2023

Analysis of antibiotic resistance and micropollutants biotransformation: bioRGO-enhanced anaerobic MBR and elucidation of degradation products

New anaerobic wastewater treatment technologies, such as the Anaerobic Membrane Bioreactor (AnMBR), offer several advantages over aerobic log systems, including energy savings, biogas production, resource recovery , a lower log production and the ability to degrade persistent pollutants to aerobic degradation. However, anaerobic processes suffer from long initiation times, low removal rates, and susceptibility to disruptions caused by organic overload, which are a consequence of slow electron transfer between fermenting bacteria and methanogens. The addition of non-biological conductive materials such as granulated activated carbon (GAC) are known to accelerate methanogenesis through the attachment of bacteria to the surface of the GAC, which is used for electron exchange .

In this project, we will investigate the enhancement of anaerobic degradation of persistent pollutants in the presence of biologically reduced graphene oxide (bioRGO). The addition of bioRGO improves the direct transfer of electrons thanks to the gelation and secretion of redox-active species by the microorganisms. The addition of bioRGO to the anaerobic community will be investigated using batch-scale biochemical methanogenic potential (BMP) tests and in a pilot-scale anaerobic membrane bioreactor (AnMBR). The bioRGO is expected to stimulate flocculation of anaerobic sludges and thereby reduce membrane fouling.

The main objectives of the ANTARES project are:

i) understand, design and apply bioRGO-enhanced AnMBR for wastewater treatment, with a primary focus on the removal of organic micropollutants and antibiotic resistance genes,

ii) demonstrate improved long-term performance of bioRGO-enhanced AnMBR in terms of reduced membrane fouling and biogas production,

iii) develop and implement high-resolution mass spectrometry methods for the analysis of antibiotics and pharmaceuticals at trace concentrations (pg-ng/L) in wastewater and sludge, and

iv) identify transformation products of target organic pollutants in different aerobic, anaerobic and anoxic treatment processes, and help establish a relationship with the enzymes and key microbial populations involved.

We will seek to demonstrate the multifunctional role of bioRGO, which acts as a redox mediator, electron transfer enhancer, adsorbent and microbial gelator. The knowledge generated about the transformation pathways of relevant antibiotics and pharmaceuticals will allow the routine analysis of their main degradation products in wastewater and clarify the impact of specific operating conditions in different aerobic wastewater treatment technologies, anoxic and anaerobic.