Environmental occurrence, risk, and removal strategies of pyrazolones: A critical review.

Pyrazolones, widely used as analgesic and anti-inflammatory pharmaceuticals, have become a significant concern because of their persistence and widespread presence in engineered (e.g., wastewater treatment plants) and natural environments. Thus, the urgent task is to ensure the effective and cost-efficient removal of pyrazolones. Advanced oxidation processes are the most commonly used removal method. Furthermore, the biodegradation of pyrazolones has been exploited using microbial communities or pure strains; however, screening for efficient degrading bacteria and clarifying the biodegradation mechanisms required further research. In this critical review, we overview the environmental occurrence of pyrazolones, their potential ecological health risks, and their corresponding removal techniques (e.g., O3 oxidation, photocatalysis, and Fenton-like process). We also emphasize the prospects for the risk and contamination control of pyrazolones in various environments using physicochemical-biochemical coupling technology. Collectively, the environmental occurrence of pyrazolones poses significant public health concerns, necessitating heightened attention and the implementation of effective methods to minimize their environmental risks.

Automated machine learning-based models for predicting and evaluating antibiotic removal in constructed wetlands.

Machine learning models can improve antibiotic removal performance in constructed wetlands (CWs) by optimizing the operation process. However, robust modeling approaches for revealing the complex biochemical treatment process of antibiotics in CWs are still lacking. In this study, two automated machine learning (AutoML) models achieved good performance with different sizes of the training dataset (mean absolute error = 9.94-13.68, coefficient of determination = 0.780-0.877), demonstrating the ability to predict antibiotic removal performance without human intervention. Explainable analysis results (the variable importance and Shapley additive explanations) revealed that the variable substrate type was more influential than the variables of influent wastewater quality and plant type. This study proposed a potential approach to comprehensively understanding the complex effects of key operational variables on antibiotic removal, which serve as a reference for optimizing operational adjustments in the CW process.

Te-induced fabrication of Pt3PdTe0.2 alloy nanocages by the self-diffusion of Pd atoms with unique MOR electrocatalytic performance.

The key to the application of direct methanol fuel cells is to improve the activity and durability of Pt-based catalysts. Based on the upshift of the d-band centre and exposure to more Pt active sites, Pt3PdTe0.2 catalysts with significantly enhanced electrocatalytic performance for the methanol oxidation reaction (MOR) were designed in this study. A series of different Pt3PdTex (x = 0.2, 0.35, and 0.4) alloy nanocages with hollow and hierarchical structures were synthesized using cubic Pd nanoparticles as sacrificial templates and PtCl62- and TeO32- metal precursors as oxidative etching agents. The Pd nanocubes were oxidized into an ionic complex, which was further co-reduced with Pt and Te precursors by reducing agents to form the hollow Pt3PdTex alloy nanocages with a face-centred cubic lattice. The sizes of the nanocages were around 30-40 nm, which were larger than the Pd templates (18 nm) and the thicknesses of the walls were 7-9 nm. The Pt3PdTe0.2 alloy nanocages exhibited the highest catalytic activities and stabilities toward the MOR after electrochemical activation in sulfuric acid solution. CO-stripping tests suggested the enhanced CO-tolerant ability due to the doping of Te. The specific activity of Pt3PdTe0.2 for the MOR reached 2.71 mA cm-2 in acidic conditions, which was higher than those of Pd@Pt core-shell and PtPd1.5 alloy nanoparticles and commercial Pt/C. A DMFC with Pt3PdTe0.2 as the anodic catalyst output a higher power density by 2.6 times than that of commercial Pt/C, demonstrating its practicable application in clean energy conversions. Density functional theory (DFT) confirmed that the alloyed Te atoms altered the electron distributions of Pt3PdTe0.2, which could lower the Gibbs free energy of the rate-determining methanol dehydrogenation step and greatly improve the MOR catalytic activity and durability.

Carbon source recovery from waste sludge reduces greenhouse gas emissions in a pilot-scale industrial wastewater treatment plant.

Carbon cycle regulation and greenhouse gas (GHG) emission abatement within wastewater treatment plants (WWTPs) can theoretically improve sustainability. Currently, however, large amounts of external carbon sources used for deep nitrogen removal and waste sludge disposal aggravate the carbon footprint of most WWTPs. In this pilot-scale study, considerable carbon was preliminarily recovered from primary sludge (PS) through short-term (five days) acidogenic fermentation and subsequently utilized on-site for denitrification in a wool processing industrial WWTP. The recovered sludge-derived carbon sources were excellent electron donors that could be used as additional carbon supplements for commercial glucose to enhance denitrification. Additionally, improvements in carbon and nitrogen flow further contributed to GHG emission abatement. Overall, a 9.1% reduction in sludge volatile solids was achieved from carbon recovery, which offset 57.4% of external carbon sources, and the indirect GHG emissions of the target industrial WWTP were reduced by 8.05%. This study demonstrates that optimizing the allocation of carbon mass flow within a WWTP has numerous benefits.

Efficient biodegradation of acetoacetanilide in hypersaline wastewater with a synthetic halotolerant bacterial consortium.

The high concentrations of salt and refractory toxic organics in industrial wastewater seriously restrict biological treatment efficiency and functional stability. However, how to construct a salt-tolerant biocatalytic community and realize the decarbonization coupled with detoxification toward green bio-enhanced treatment, has yet to be well elucidated. Here, acetoacetanilide (AAA), an important intermediate for many dyes and medicine synthesis, was used as the model amide pollutant to elucidate the directional enrichment of halotolerant degradative communities and the corresponding bacterial interaction mechanism. Combining microbial community composition and molecular ecological network analyses as well as the biodegradation efficiencies of AAA and its hydrolysis product aniline (AN) of pure strains, the core degradative bacteria were identified during the hypersaline AAA degradation process. A synthetic bacterial consortium composed of Paenarthrobacter, Rhizobium, Rhodococcus, Delftia and Nitratireductor was constructed based on the top-down strategy to treat AAA wastewater with different water quality characteristics. The synthetic halotolerant consortium showed promising treatment ability toward the simulated AAA wastewater (AAA 100-500 mg/L, 1-5% salinity) and actual AAA mother liquor. Additionally, the comprehensive toxicity of AAA mother liquor significantly reduced after biological treatment. This study provides a green biological approach for the treatment of hypersaline and high concentration of organics wastewater.

Performance and bacterial community analysis of a two-stage A/O-MBBR system with multiple chambers for biological nitrogen removal.

A two-stage anoxic/oxic (A/O)-moving bed biofilm reactor (MBBR) system with multiple chambers was established for municipal wastewater treatment. At the total hydraulic retention time (HRT) of 11.2 h and nitrate recycling ratio of 1, the removal efficiencies reached 83.8%, 82.5%, and 77.8% for soluble chemical oxygen demand (SCOD), 98.0%, 97.5%, and 94.9% for ammonia nitrogen (NH4+-N), and 91.8%, 92.0%, and 87.7% for total inorganic nitrogen (TIN) in summer, autumn and winter, respectively. Biofilms with functional bacterial populations were formed in the pre-anoxic reactors, the pre-oxic reactors, the post-anoxic reactors and the post-oxic reactors of the two-stage A/O-MBBR system. The highest nitrification potential was found in the last oxic reactor of the first A/O-MBBR subsystem with the highest relative abundances of the functional genes including [EC:1.14.99.39] and [EC:1.7.2.6]). The highest denitrification potential was found in the post-anoxic reactors with the highest relative abundances of the functional genes including [EC:1.7.2.1], [EC:1.7.2.5] and [EC:1.7.2.4]. This work constructed an efficient municipal biological nitrogen removal technology to achieve high effluent nitrogen standards in winter, and investigated its working mechanism to provide a basis for its design and optimization.