Fate and removal of emerging contaminants in anaerobic fluidized membrane bioreactor filled with thermoplastic gel as biofilm support

Enhanced detection of pesticides: evaluating monocarbamoylcarboxylic acids modified with amines for glyphosate and dicamba sensitivity

In this work a series of monocarbamoylcarboxylic acids (MCCAs) N-functionalized with different amines were evaluated to detect the pesticides glyphosate (Gly) and dicamba (Dic). The MCCAs have molar absorptivity coefficients (ε) three orders of magnitude higher than pesticides facilitating the measurements under UV-Vis spectroscopy. These compounds have the isolectric point (IEP) in the range of pH 3.04-4.82 and beyond are negative charged. The absorption properties of the compounds are pH-dependent due to the protonation and deprotonation of their molecules, the adsorption band shifts to a longer wavelength as the pH increases and in some ligands a hyperchromic effect is observed. The titration of MCCAs with a pesticide generates a change in the adsorption band and the sensitivity of the response is also pH-dependent. The sensitivity of MCCAs towards pesticides decreased at pH 5.0 and increased at pH 7.0 and 9.0 which is clearly influenced by the acid-base equilibriums in water. The response was more sensitive towards dicamba than with glyphosate, exhibiting linear concentration intervals up to 100 µM with 1a at pH 4 and 85 µM in compounds 2b and 2c at pH 7.0. The 1H NMR analysis in DMSO‑d6 of compounds 2a and 2c in presence of glyphosate and dicamba showed changes in the hydrogen signals indicating the interaction of these MCCAs with the pesticides in specific sites of their molecules. These MCCAs, proved to be promising molecular platforms for the optical detection of glyphosate and dicamba due to their pH-adjustable sensitivity and their ability to show significant electrostatic interactions, enabling pesticide detection over a wide concentration range.

Anaerobic removal of contaminants of emerging concern in municipal wastewater: Eco-toxicological risk evaluation and strategic selection of optimal treatment

In the last decades, the interest for anaerobic process as a mainstream treatment of municipal wastewater increased due to the development of high-rate anaerobic bioreactors able to achieve removal kinetics comparable to the aerobic ones. Moreover, they have the additional advantages of energy production, nutrient recovery and reduced excess sludge yield, which are interesting features in the frame of sustainability wastewater treatment goals. These appealing factors increased the research demand to evaluate the potential of the anaerobic removal for contaminants of emerging concern (CECs) in municipal wastewater. However, despite the growing interest for the subject, literature is still fragmentary and reviews are mainly focused on specific technologies and target compounds or groups of compounds. We propose this review with the main objectives of presenting the state of knowledge, the performances of anaerobic systems for CECs' removal and, more important, to give the reader guidelines for optimal treatment selection. In the first part, a general overview of the investigated technologies at different scale, with a special focus on the recently proposed enhancements, is presented. Collected data are analysed to select the target CECs and the analysis results employed to define the optimal technological solution for their removal. A first novelty element of the paper is the original procedure for contaminant selection consisting of a risk assessment tool for CECs, based on their frequency of detection, concentration and potential for biosorption in wastewater treatment plants. Data of selected target CECs are combined with compound and technology performance data to implement a flowchart tool to evaluate the optimal treatment strategy, which constitute another, even more important, novelty element of this study.

Recent Advances in the Biocatalytic Mitigation of Emerging Pollutants: A Comprehensive Review

The issue of environmental pollution has been worsened by the emergence of new contaminants whose morphology is yet to be fully understood. Several techniques have been adopted to mitigate the pollution effects of these emerging contaminants, and bioremediation involving plants, microbes, or enzymes has stood out as a cost-effective and eco-friendly approach. Enzyme-mediated bioremediation is a very promising technology as it exhibits better pollutant degradation activity and generates less waste. However, this technology is subject to challenges like temperature, pH, and storage stability, in addition to recycling difficulty as it is arduous to isolate them from the reaction media. To address these challenges, the immobilization of enzymes has been successfully applied to ameliorate the activity, stability, and reusability of enzymes. Although this has significantly increased the uses of enzymes over a wide range of environmental conditions and facilitated the use of smaller bioreactors thereby saving cost, it still comes with additional costs for carriers and immobilization. Additionally, the existing immobilization methods have their individual limitations. This review provides state-of-the-art information to readers focusing on bioremediation using enzymes. Different parameters such as: the sustainability of biocatalysts, the ecotoxicological evaluation of transformation contaminants, and enzyme groups used were reviewed. The efficacy of free and immobilized enzymes, materials and methods for immobilization, bioreactors used, challenges to large-scale implementation, and future research needs were thoroughly discussed.