Removal of bacterial pathogens and antibiotic resistance bacteria by anaerobic sludge digestion with thermal hydrolysis pre-treatment and alkaline stabilization post-treatment.

Autor: Cuetero-Martínez Y; Subdirección de Hidráulica y Ambiental, Instituto de Ingeniería, Universidad Nacional Autónoma de México, 04510 CDMX, Mexico; Doctorado en Ciencias Bioquímicas, Universidad Nacional Autónoma de México, 04510 CDMX, Mexico., Flores-Ramírez A; Subdirección de Hidráulica y Ambiental, Instituto de Ingeniería, Universidad Nacional Autónoma de México, 04510 CDMX, Mexico., De Los Cobos-Vasconcelos D; Subdirección de Hidráulica y Ambiental, Instituto de Ingeniería, Universidad Nacional Autónoma de México, 04510 CDMX, Mexico., Aguirre-Garrido JF; Departamento de Ciencias Ambientales, Universidad Autónoma Metropolitana - Unidad Lerma, 52005 Lerma de Villada, Edo. Mex, Mexico., López-Vidal Y; Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, 04510 CDMX, Mexico., Noyola A; Subdirección de Hidráulica y Ambiental, Instituto de Ingeniería, Universidad Nacional Autónoma de México, 04510 CDMX, Mexico. Electronic address: noyola@pumas.ii.unam.mx.
Jazyk: angličtina
Zdroj: Chemosphere [Chemosphere] 2023 Feb; Vol. 313, pp. 137383. Date of Electronic Publication: 2022 Nov 24.
DOI: 10.1016/j.chemosphere.2022.137383
Abstrakt: Primary sludge (PS) is associated with public health and environmental risks, so regulations focus on reducing the pathogenic and heavy metal contents of the treated material (biosolids), intended for soil amendments and land reclamation. The regulations set limits for Escherichia coli (or fecal coliforms), Salmonella spp., helminth eggs and enterovirus. However, the potential risk due to antibiotic resistant bacteria (ARB) and other human potential pathogenic bacteria (HPB) are not considered. In this work, three sludge treatment processes, having in common an anaerobic digestion step, were applied to assess the removal of regulated bacteria (fecal coliforms, Salmonella spp), ARB and HPB. The treatment arrangements, fed with PS from a full-scale wastewater treatment plant were: 1) Mesophilic anaerobic digestion followed by alkaline stabilization post-treatment (MAD-CaO); 2) Thermophilic anaerobic digestion (TAD) and, 3) Pre-treatment (mild thermo-hydrolysis) followed by TAD (PT-TAD). The results address the identification, quantification (colony forming units) and taxonomic characterization of ARB resistant to β-lactams and vancomycin, as well as the taxonomic characterization of HPB by sequencing with PacBio. In addition, quantification based on culture media of fecal coliforms and Salmonella spp. is presented. The capabilities and limitations of microbiological and metataxonomomic analyses based on PacBio sequencing are discussed, emphasizing that they complement each other. Genus Aeromonas, Acinetobacter, Citrobacter, Enterobacter, Escherichia, Klebsiella, Ochrobactrum, Pseudomonas and Raoultella, among others, were found in the PS, which are of clinical or environmental importance, being either HPB, HPB-ARB, or non-pathogenic ARB with the potentiality of horizontal gene transfer. Based on the analysis of fecal coliforms and Salmonella spp., the three processes produced class A (highest) biosolids, suitable for unrestricted agriculture applications. Mild thermo-hydrolisis was effective in decreasing ARB cultivability, but it reappeared after the following TAD. O. intermedium (HPB-ARB) was enriched in MAD and TAD while Laribacter hongkongensis (HPB) did persist after the applied treatments.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2022 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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