Characterization of dissolved organic matter in wastewater using liquid chromatography-high resolution mass spectrometry
- Autores: Yaroslav Verkh
- Directores de la Tesis: Mira Petrovic (dir. tes.)
- Lectura: En la Universitat de Girona ( España ) en 2019
- Idioma: español
- Tribunal Calificador de la Tesis: Antoni Ginebreda Martí (presid.), Wolfgang Gernjak (secret.), Nikolaos Thomaidis (voc.)
- Programa de doctorado: Programa de Doctorado en Ciencia y Tecnología del Agua por la Universidad de Girona
- Materias:
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- Resumen
Individual hazardous chemicals and substance mixtures with synergistic toxicity ef-fects occur in the dissolved organic matter (DOM) of wastewater and negatively im-pact human health. Yet a large number of chemicals and their treatment by-products in wastewater makes the tracking of individual compounds nearly impossible and de-mands new analytical strategies.
The thesis describes the development and evaluation of non-targeted and suspect anal-ysis methods aimed at the transformation of DOM and micro-contaminants of interest during wastewater treatment using liquid chromatography-high-resolution mass spec-trometry (LC-HRMS) data.
On one hand, a non-targeted method to track transformations of DOM in a multiphase wastewater treatment using LC-HRMS data was developed. LC-MS signals were ex-tracted, aligned, and had their isotopologues clustered and elemental composition pre-dicted using open license software MZmine 2 in a way that conceptually prioritized the detection of anthropogenic compounds. After, unreliable signals were removed using own methodology in R computing environment. This data analysis revealed that the secondary treatment removed 67% detected DOM signals, while 24% new signals appeared relatively to the influent DOM. The number of large molecules (> 450 Da) decreased and the number of unsaturated molecular features of the effluent organic matter (OM) increased. Van Krevelen plots revealed the distribution of unsaturation and heteroatoms.
The non-targeted methodology was applied to quadrupole-time of flight (QTOF) and LTQ-Orbitrap HRMS data to test the influence of instrumental setup on analytical conclusions. The Orbitrap setup showed a higher amount of detected molecular fea-tures and a higher rate of molecular formula assignment for the detected molecular features. The QTOF setup uncovered a subset of high molecular weight features due to the stronger stability of resolving power in the QTOF setup at higher m/z.
On the other hand, this thesis approached the transformation of chemicals in wastewater DOM by analyzing micro-contaminants and their confirmed, as well as tentative, transformation products (TPs) to supplement the developed non-targeted analysis. The suspect screening of micro-contaminants, using Thermo Exact Finder software and an own post-processing pipeline in R, yielded 11 pharmaceuticals and their TPs in a multistage WWT using own detection and data processing method. Hereby, secondary treatment was efficient in removing chemicals, while the removal in tertiary treatment was less consistent. Additionally, the screening method was ap-plied to a novel granular bio-activated carbon-ultrafiltration (BAC-UF) system. The analysis of 11 pharmaceuticals and their TPs in four time series showed that BAC had led to a high removal of chemicals in the first months of the reactor runtime, while the efficiency dropped in the latter months due to BAC filter saturation.
