Removal of pharmaceutical compounds from the liquid phase of anaerobic sludge in a pilot-scale high-rate algae-bacteria pond

Biodegradation of pharmaceutical contaminants in wastewater using microbial consortia: Mechanisms, applications, and challenges

Pharmaceuticals, including non-steroidal anti-inflammatory drugs and antibiotics, have been increasingly detected in wastewater and pose substantial ecological and public health concerns due to their persistence and bioactivity. Conventional treatment processes are often insufficient for their complete removal, highlighting the need for advanced bioremediation strategies. This review critically examines the mechanisms, applications, and challenges of microbial consortia for pharmaceutical biodegradation. It emphasizes their synergistic metabolic pathways, such as cross-feeding, co-metabolism, and enzymatic cascades, that enable efficient degradation of complex contaminants. Recent advancements, such as membrane bioreactors, bioaugmentation with genetically engineered consortia, and integrated systems coupling microbial processes with advanced oxidation processes, are reviewed for their potential to enhance treatment efficacy, scalability, and sustainability. Comparative analysis underscores microbial consortia's superiority over single-strain systems and adsorption techniques in treating complex contaminant mixtures, achieving up to 100 % removal efficiency for specific compounds. Persistent challenges include microbial community instability, the toxicity of transformation products, and regulatory constraints related to genetically modified organisms. Strategic solutions are proposed, such as pilot-scale implementation of tailored consortia, Internet of things (IoT)-enabled real-time monitoring, and circular economy approaches for resource recovery. By addressing these challenges, microbial consortia-based biodegradation emerges as a transformative solution for pharmaceutical wastewater treatment, aligning with global sustainability goals. This review provides actionable insights for optimizing bioremediation frameworks, informing policy, and advancing research in environmental microbiology and wastewater engineering.

Microalgae-based membrane bioreactor for wastewater treatment, biogas production, and sustainable energy: A review

Managing wastewater and using renewable energy sources are challenges in achieving sustainable development goals. This study provides an overview of the factors influencing the performance of algae-based membrane bioreactors (AMBRs) for contaminant removal from wastewater and biogas production. This review highlights that the performance of AMBRs in removing total phosphorus (TP) and nitrogen (N) from wastewater can reach up to 93% and 97%, respectively, depending on parameters such as pH, hydraulic retention time (HRT), and algae concentration. Moreover, the removal of H2S from biogas substantially depends on the type of bioreactor used. Furthermore, algal biomass has proven to be a viable option for biogas production and CO2 sequestration, contributing to carbon neutrality. This review also underscores that microalgae are a valuable feedstock, either alone or in combination with other raw materials, for biogas production. In conclusion, this review outlines that maximizing the performance of bioreactors and the efficiency of microalgae used for biogas production and wastewater treatment requires careful control of parameters, such as HRT, solid retention time, pH, and temperature. Additionally, pH and the carbon-to-nitrogen ratio (C:N) are factors influencing CH4 yield during microalgae anaerobic digestion (AD). Further research is needed to evaluate the operational costs of AMBRs used for wastewater treatment and to compare the biogas yield from different types of bioreactors under similar conditions, including the use of the same feedstock.

Photodegradation of typical psychotropic drugs in the aquatic environment: a critical review

Continuous consumption combined with incomplete removal during wastewater treatment means residues of psychotropic drugs (PDs), including antidepressants, antipsychotics, antiepileptics and illicit drugs, are continuously entering the aquatic environment, where they have the potential to affect non-target organisms. Photochemical transformation is an important aspect to consider when evaluating the environmental persistence of PDs, particularly for those present in sunlit surface waters. This review summarizes the latest research on the photodegradation of typical PDs under environmentally relevant conditions. According to the analysis results, four classes of PDs discussed in this paper are influenced by direct and indirect photolysis. Indirect photodegradation has been more extensively studied for antidepressants and antiepileptics compared to antipsychotics and illicit drugs. Particularly, the photosensitization process of dissolved organic materials (DOM) in natural waters has received significant research attention due to its ubiquity and specificity. The direct photolysis pathway plays a less significant role, but it is still relevant for most PDs discussed in this paper. The photodegradation rates and pathways of PDs are influenced by various water constituents and parameters such as DOM, nitrate and pH value. The contradictory results reported in some studies can be attributed to differences in experimental conditions. Based on this analysis of the existing literature, the review also identifies several key aspects that warrant further research on PD photodegradation. These results and recommendations contribute to a better understanding of the environmental role of water matrixes and provide important new insights into the photochemical fate of PDs in aquatic environments.

Microalgal-based carbon encapsulated iron nanoparticles for the removal of pharmaceutical compounds from wastewater

This study evaluates the effectiveness of microalgal-based carbon-encapsulated iron nanoparticles (ME-nFe) in the removal of pharmaceutical compounds (PhACs) from water solutions and real municipal effluent at a laboratory scale. The investigated PhACs were chosen to represent different classes of synthetic drugs: antibiotics, anti-inflammatory drugs, antihypertensives, antiepileptics, neuroprotectors, and antidepressants. The adsorbent material was produced through hydrothermal carbonization (225 °C for 3 h), using microalgae grown on wastewater as the carbon source. ME-nFe showed heterogeneity in terms of porosity (with both abundance of macro and mesopores), a total pore volume of 0.65 mL g-1, a specific surface area of 117 m2 g-1 and a total iron content of 40%. Laboratory scale adsorption tests (1 g L-1 of nanoparticles with 2 min contact time) showed high removal for the most hydrophobic compounds. Removal efficiencies were high (over 98%) for Irbesartan, Ofloxacin and Diclofenac, promising (over 65-80%) for Clarithromycin, Fluoxetine, Lamotrigine and Metoprolol, but low for Gabapentin-Lactam and Propyphenazone (<20%). Electrostatic interactions between the drugs and the surface of the nanoparticles may account for the observed data, although additional removal mechanisms cannot be ruled out.

Role of microalgae-bacterial consortium in wastewater treatment: A review

In the global effort to reduce CO2 emissions, the concurrent enhancement of pollutant degradation and reductions in fossil fuel consumption are pivotal aspects of microalgae-mediated wastewater treatment. Clarifying the degradation mechanisms of bacteria and microalgae during pollutant treatment, as well as regulatory biolipid production, could enhance process sustainability. The synergistic and inhibitory relationships between microalgae and bacteria are introduced in this paper. The different stimulators that can regulate microalgal biolipid accumulation are also reviewed. Wastewater treatment technologies that utilize microalgae and bacteria in laboratories and open ponds are described to outline their application in treating heavy metal-containing wastewater, animal husbandry wastewater, pharmaceutical wastewater, and textile dye wastewater. Finally, the major requirements to scale up the cascade utilization of biomass and energy recovery are summarized to improve the development of biological wastewater treatment.

Scale-up of microalgal systems for decarbonization and bioproducts: Challenges and opportunities

The threat of global climate change presents a significant challenge for humanity. Microalgae-based carbon capture and utilization (CCU) technology has emerged as a promising solution to this global issue. This review aims to comprehensively evaluate the current advancements in scale-up of microalgae cultivation and its applications, specifically focusing on decarbonization from flue gases, organic wastewater remediation, and biogas upgrading. The study identifies critical challenges that need to be addressed during the scale-up process and evaluates the economic viability of microalgal CCU within the carbon market. Additionally, it analyzes the commercial status of microalgae-derived products and highlights those with high market demand. This review serves as a crucial resource for researchers, industry professionals, and policymakers to develop and implement innovative approaches to enhance the efficiency of microalgae-based CO2 utilization while addressing the challenges associated with the scale-up of microalgae technologies.