Removal of nitrogen and pharmaceutical compounds in a biofilm system

Abstract

As global wastewater generation reaches an estimated 380 billion cubic meters annually, the primary challenge for sanitation infrastructure has shifted from volumetric management to the mitigation of chemical matrices, specifically pharmaceutical active compounds (PhACs). Conventional treatment systems often fail to sequester theses recalcitrant pollutants, which propagate antimicrobial resistance and threaten aquatics ecosystems. This thesis investigates the synergistic potential of an anaerobic ammonium oxidation (anammox) consortium cultivated within a moving bed biofilm reactor (MBBR) for the simultaneous removal of nitrogenous compounds and five target PhACs – marbofloxacin, ofloxacin, enrofloxacin, sulfamethoxazole and carbamazepine. The experimental results demonstrated that the MBBR system successfully decoupled biomass retention from hydraulic retention time (HRT), allowing for the enrichment of slow-growing anammox bacteria on K1-shaped biofilm carriers. The system achieved nitrogen removals, maintaining stability despite fluctuations in total nitrogen loading. Batch kinetic studies revealed that while nitrogen removal followed a first order model (R2 up to 0.8299), PhAC attenuation was highly compound specific. The findings from this project suggest that, while anammox-mediated systems are highly efficient for energy-neutral nitrogen removal, the attenuation of PhACs relies on maintenance of diverse and stratified microbial community. This research provides a fundamental framework for designing next-generation wastewater infrastructure capable of addressing both nutrient and emerging micropollutants in a single-stage process.