Research Vision
Research Interests
​Microorganisms play essential roles in remediation strategies to remove anthropogenic contaminants. However, contaminants containing oxidized functional groups, such as carbonyl, halogens, sulfonyl, cyano, and nitro groups, are less prone to microbial-catalyzed oxidation, requiring an anaerobic step to activate the molecule for further transformation. Sequential or concurrent anaerobic-aerobic systems have been successfully implemented to treat chloroethenes, azo dyes, explosives, and pesticides. However, each of these contaminants has a unique degradation route and is metabolized by different enzymes, forming distinct transformation products. This research project aims to enrich microorganisms able to perform the reduction of the parent contaminant and the oxidation of the transformation products using soil, sludge, and sediments as inoculum. Molecular biology tools will be used to identify genes related to the transformation of the contaminants. Strategies to enhance their degradation rate will be investigated, such as the use of co-substrates, redox mediators, and vitamins. Bioreactors will be designed to promote high-rate removal of these contaminants. An integrated approach will be used to evaluate strategies for the bioremediation of contaminated sites combining engineering design, molecular ecology, and ecotoxicology. The toxic effects of transformation products on different organisms will be considered to determine safe degradation pathways.
Anaerobic-aerobic biological processes to treat contaminants containing oxidized functional groups
​I plan to pursue in-depth investigations into the fate of emerging contaminants in natural environments and their interactions with microorganisms and soil and sediment components. I expect my research to advance the use of biological processes for the remediation of contaminated sites and to increase the efficiency and sustainability of wastewater treatment processes, to provide information to regulatory agencies and institutions responsible for risk assessment of toxic chemicals, and to shed light on mechanisms leading to the accumulation or attenuation of contaminants in different environmental matrices.
Assessment of emerging contaminant toxicity to key microorganisms in wastewater treatment processes
​Conventional wastewater treatment plants (WWTPs) rely on a combination of physical, chemical, and biological processes for the removal of organic matter, nutrients, pollutants, and pathogens. As the diversity of contaminants released in wastewater increases, the potential toxic effects of these contaminants on microorganisms participating in organics and nutrient removal in biological reactors in WWTPs must be investigated. This project aims to conduct a broad assessment of the toxic effects of emerging contaminants on microbial communities found in biological reactors, such as heterotrophic and nitrifying bacteria in activated sludge, methanogens and denitrifying bacteria in anaerobic sludge, and anammox biomass. Experiments will be performed to assess the role of biomass immobilization and extracellular polymeric substances production on the attenuation of inhibitory effects caused by emerging contaminants. In addition, the use of chelators and metals as micronutrients will be assessed to enhance microbial activity in biological reactors. The results of this study will guide decisions regarding the operation of biological reactors in WWTPs and help increase the efficiency of biological processes.
Microplastics interactions with emerging contaminants and their degradation products
​Plastics are versatile polymeric materials with diverse applications. Annually, large amounts of plastic end up entering aquatic environments due to inappropriate solid waste disposal. Recent studies show that plastics can act as vectors of organic contaminants through sorption processes. Small plastic particles can adsorb significant amounts of hydrophobic contaminants, leading to the accumulation and transport of these compounds in the aquatic environment and, eventually, exposing organisms to the toxic effects of these contaminants through the ingestion of contaminated plastics. This project aims to investigate the interactions between plastic and organic contaminants in bench-scale experiments, mesocosms, and surface water bodies. The occurrence of micro and nanoplastics and sorbed organic contaminants will also be investigated in reclaimed water. This study will help to understand the impact of pollution caused by different types of plastics on the retention and accumulation of emerging contaminants in aquatic environments.​
