Biotransformation of acetaminophen by a bacterial consortium isolated from wastewater treatment plant and household compost: metabolite profiling and kinetic insights.

Diclofenac (DCF) belongs to the class of nonsteroidal anti-inflammatory drugs, which is one of the most consumed by population and detected in raw sewage. Several studies have reported variable removal rates by biodegradation of diclofenac in wastewater treatment plants (WWTPs). This study deals with the evaluation of the biodegradation of DCF by a bacterial consortium (obtained from pure cultures of Enterobacter hormaechei D15 and Enterobacter cloacea D16), which were isolated from household compost and Algerian WWTP, respectively, as sole carbon source and by co-metabolism, using glucose as carbon source. A 98% removal rate of DCF was observed when it is used as the sole carbon source, whilst only 44% of DCF was removed in co-metabolic conditions. Two metabolites were identified using ultra-high-performance liquid chromatography coupled to electrospray injection tandem mass spectrometry analysis (UHPLC-ESI-MS/MS); one of them was identified as 4'-hydroxy-DCF, and the second metabolite was suspected to be a nitro derivative of DCF, according to comparison with the literature. Biodegradation of DCF by this bacterial consortium generates relatively safe final by-products.

Background: The presence of pharmaceuticals at low concentrations (ng to μg) in the environment has become a hot spot for researchers in the past decades due to the unknown environmental impact and the possible damages they might have to the plantae and fauna present in the aquatic systems, as well as to the other living organisms. Objectives: The aim of the present investigation was to develop a bacterial consortium isolated from different origins to evaluate the ability of such a consortium to remove a mixture of pharmaceuticals in the batch system at lab scale, as well as assessment of its resistance to the other micropollutants present in the environment. Material and Methods: Using a closed bottle test, biodegradation of the mixed pharmaceuticals including Diclofenac (DCF), Ibuprofen (IBU), and Sulfamethoxazole (SMX) (at a concentration of 3 mg.L-1 of each drug) by the bacterial consortium was investigated. The test was carried out under metabolic (pharmaceutical was used as the sole source of carbon) and co-metabolic condition (in the presence of glucose). Finally, the ability of the bacterial consortium to resist other micropollutants like antibiotics and heavy metals was investigated. Results: Under the metabolic condition, the mixed bacteria (i.e., consortium) were able to metabolize 23.08% and 9.12% of IBU, and DCF at a concentration of 3 mg.L-1 of each drug, respectively. Whereas, in co-metabolic conditions, IBU was eliminated totally, in addition, 56% of the total concentration of DCF was removed, as well. In both metabolic and cometabolic conditions, removal of SMX was not observed. The selected bacteria were able to resist to most of the applied antibiotics and the used heavy metals, except mercury, where only one strain (S4) was resistant to the later heavy metal. Conclusion: Results suggest that the developed consortium might be an excellent candidate for the application in the bioremediation process for treating ecosystems contaminated with the pharmaceutical.

Characterization of metoprolol biodegradation and its transformation products generated in activated sludge batch experiments and in full scale WWTPs

Transformation products of clindamycin in moving bed biofilm reactor (MBBR)

Occurrence and environmental impact of pharmaceutical residues from conventional and natural wastewater treatment plants in Gran Canaria (Spain)

Constructed wetlands (CW) are man-made systems that mimic the natural wetlands. They can be used for various purposes, including wastewater treatment, stormwater management, and carbon sequestration. Wetlands naturally absorb and store carbon from the atmosphere, and CW can replicate this process by using plants and microorganisms to remove and store carbon from the water. Conventional wastewater treatment plants (WWTP) use more energy and contribute to carbon emissions, so many industries are looking for ways to reduce greenhouse gas (GHG) emissions. While CW have been widely used for municipal and sewage treatment, their use as an alternative or supplement to industrial wastewater treatment, particularly in the oil and gas and petrochemical industries, is limited. However, CW have the potential to promote carbon sequestration and have a lower cost of capital and operating expenses compared to conventional WWTP, while also emitting lower GHG emissions. A case study is presented for two types of system in which one is actual operating conventional WWTP in Malaysia design and operate at 60m3/d and a hybrid CW of equivalent treatment capability and capacity. The case study found that GHG emissions from a conventional WWTP were approximately 3.75 times higher than the hybrid CW system with the same treatment capacity. For a small capacity WWTP at 60m3 per day, converting the treatment system from conventional WWTP to CW will reduce approximately 45.7t CO2 eq per year based on Life Cycle Assessment (LCA) calculation. The conventional WWTP consumed much higher power especially from the air blower compared to CW where limited number of equipment is required. The additional carbon sink for CW from carbon sequestration from plant, soil decomposition and sediment has not been quantified in the LCA calculation. Hence, it is expected the actual CO2 eq emission for CW is much lesser than the conventional WWTP. With all the benefit identified and the proven success case in several places, the adoption of CW as an industrial WWTP should be widely promoted as the replacement of conventional WWTP for sustainable future.

Constructed wetlands (CW) are man-made systems that mimic the natural wetlands. They can be used for various purposes, including wastewater treatment, stormwater management, and carbon sequestration. Wetlands naturally absorb and store carbon from the atmosphere, and CW can replicate this process by using plants and microorganisms to remove and store carbon from the water. Conventional wastewater treatment plants (WWTP) use more energy and contribute to carbon emissions, so many industries are looking for ways to reduce greenhouse gas (GHG) emissions. While CW have been widely used for municipal and sewage treatment, their use as an alternative or supplement to industrial wastewater treatment, particularly in the oil and gas and petrochemical industries, is limited. However, CW have the potential to promote carbon sequestration and have a lower cost of capital and operating expenses compared to conventional WWTP, while also emitting lower GHG emissions. A case study is presented for two types of system in which one is actual operating conventional WWTP in Malaysia design and operate at 60m3/d and a hybrid CW of equivalent treatment capability and capacity. The case study found that GHG emissions from a conventional WWTP were approximately 3.75 times higher than the hybrid CW system with the same treatment capacity. For a small capacity WWTP at 60m3 per day, converting the treatment system from conventional WWTP to CW will reduce approximately 45.7t CO2 eq per year based on Life Cycle Assessment (LCA) calculation. The conventional WWTP consumed much higher power especially from the air blower compared to CW where limited number of equipment is required. The additional carbon sink for CW from carbon sequestration from plant, soil decomposition and sediment has not been quantified in the LCA calculation. Hence, it is expected the actual CO2 eq emission for CW is much lesser than the conventional WWTP. With all the benefit identified and the proven success case in several places, the adoption of CW as an industrial WWTP should be widely promoted as the replacement of conventional WWTP for sustainable future.

Wastewaters are considered as hotspot for multidrug resistant bacteria and genes, especially for extended spectrum beta lactamase producing Escherichia coli (ESBL-EC), which pose significant public health concern. Conventional wastewater treatment plants (WWTPs) are not designed to remove such resistant bacteria before discharge. This study, therefore, aimed to evaluate and compare the performance of two municipal WWTPs in eliminating ESBL-EC in Hatay province, Türkiye. The isolates were further characterized by antimicrobial susceptibility testing, pulsed-field gel electrophoresis (PFGE) and resistance gene analysis. A total of 24 wastewater samples [influent (n = 12) and effluent (n = 12)] were collected from both conventional and advanced biological WWTP. A total of 66 ESBL-EC were isolated and confirmed as ESBL producer. The abundance of ESBL-EC was significantly more prevalent in the influent water samples (mean 3.86 ± 0.11 log cfu/ml), when compared to the effluent wastewater samples (mean 2.20 ± 0.27 log cfu/ml). According to the PFGE results (cut-off > 85%), 16 isolates were clonally related, whereas 49 isolates were singletons and one isolate could not be evaluated. Besides beta-lactam antibiotics, the isolates were highly resistant to tetracycline (63.63%) and fluoroquinolones (43.93%). The blaCTX-M gene was the most frequently detected gene in the isolates (86.36%), among which the blaCTX-M-15 type (86.36%) was the most frequently detected. At least two disinfectant resistance genes were also detected in each of the isolates. Even though both WWTP were found to be effective in reducing ESBL-EC counts, not well enough to complete elimination, showing the potential public health risk.

Biodegradation of linear alkylbenzene sulfonate by a two-member facultative anaerobic bacterial consortium

Microplastic abundance and removal via an ultrafiltration system coupled to a conventional municipal wastewater treatment plant in Thailand

Aerobic and anaerobic formation and biodegradation of guanyl urea and other transformation products of metformin

Sulfamethoxazole(SMX) passes through conventional wastewater treatmentplants (WWTPs) mainly unaltered. Under anoxic conditions sulfate-reducingbacteria can transform SMX but the fate of the transformation products(TPs) and their prevalence in WWTPs remain unknown. Here, we reportthe anaerobic formation and aerobic degradation of SMX TPs. SMX biotransformationwas observed in nitrate- and sulfate-reducing enrichment cultures.We identified 10 SMX TPs predominantly showing alterations in theheterocyclic and N4-arylamine moieties.Abiotic oxic incubation of sulfate-reducing culture filtrates ledto further degradation of the major anaerobic SMX TPs. Upon reinoculationunder oxic conditions, all anaerobically formed TPs, including thesecondary TPs, were degraded. In samples collected at different stagesof a full-scale municipal WWTP, anaerobically formed SMX TPs weredetected at high concentrations in the primary clarifier and digestedsludge units, where anoxic conditions were prevalent. Contrarily,their concentrations were lower in oxic zones like the biologicaltreatment and final effluent. Our results suggest that anaerobicallyformed TPs were eliminated in the aerobic treatment stages, consistentwith our observations in batch biotransformation experiments. Moregenerally, our findings highlight the significance of varying redoxstates determining the fate of SMX and its TPs in engineered environments.

UV and (V)UV irradiation of sitagliptin in ultrapure water and WWTP effluent: Kinetics, transformation products and degradation pathway

This work evaluates the theoretical availability of energy and the sludge production in a wastewater treatment plant (WWTP) that associates UASB reactors and submerged aerated biofilters (BF). A comparison among the behaviour of a pilot plant operating under constant hydraulic load (trial 1) and under hourly variation of hydraulic load, with sludge recirculation from the BF to the UASB (trial 2), was carried out. The results show that it is possible to suppress complementary units of thickening and digestion, once the sludge in the bottom of the UASB reaches concentrations of 4,5% TS and 50 to 70% (VS/TS). A comparison of the biogas availability in a WWTP with primary settlers and anaerobic digesters is accomplished. The biogas production in a UASB + BF WWTP is larger than double that produced on the conventional WWTP. The UASB reactor acts on the total COD present in the wastewater (soluble COD + suspended COD), which does not happen in a conventional WWTP (only the suspended COD retained in the primary settler and in the biological sludge is converted to methane). The sludge production, the energy requirement for aeration and the necessary volume for the reactors of the two kinds of WWTP are appraised.

Investigating the transformation products (TPs) of organic micropollutants in aquatic environments is crucial for understanding their fate, evaluating ecological and human health risks, and developing effective mitigation strategies to protect water quality. Thus, it is essential to establish an efficient workflow with low technical complexity for high-throughput TP identification. In this study, high resolution mass spectrometry (HRMS), stable isotope-labeled compounds, and similarity analysis were combined to develop an advanced computational approach for investigating the phototransformation processes of ciprofloxacin. A total of 68 tentatively ciprofloxacin-related TPs were extracted through isotope labeling experiments and formula filtering. Furthermore, structural elucidation of 42 TPs was achieved by combining HRMS/MS fragments and stable isotope labeling results, revealing that piperazinyl and cyclopropyl moieties are the key reaction sites of ciprofloxacin under solar irradiation. A novel similarity analysis workflow was developed to map the phototransformation pathways, establishing 80 parent-TP pairings. Dealkylation, oxygen addition, decarboxylation, and defluorination were found to be the dominant phototransformation reaction types of ciprofloxacin. The study highlights the complexity of ciprofloxacin phototransformation and provides a robust computational framework for elucidating the degradation pathways of organic contaminants. The developed methodology can be extended to study other emerging contaminants, supporting the design of more effective water treatment strategies and comprehensive risk assessments.