Flow cytometry as a tool for the rapid enumeration of 1-µm microplastics spiked in wastewater and activated sludge after coagulation-flocculation-sedimentation.
Chemosphere
; 359: 142328, 2024 Jul.
Article
de En
| MEDLINE
| ID: mdl-38740336
ABSTRACT
Considering the limited literature and the difficulty of quantifying 1-µm micro-nanoplastics (1-µm MNP) in complex aqueous matrices such as wastewater and sludge, the removal rate of these very small particles in wastewater treatment plants (WWTP) represents a major challenge. In this study, coagulation-flocculation-sedimentation (CFS) with aluminum salts was investigated to evaluate the removal of 1-µm MNPs spiked in tap water, raw wastewater, pre-settled wastewater, and activated sludge. Quantification of 1-µm MNP was performed using the high-throughput flow cytometry (FCM) analysis which takes only a few minutes and produces results with high accuracy and reproducibly. The results indicated that the 1-µm MNPs were highly stable in pure water and unable to settle rapidly. In raw wastewater, sedimentation without coagulants removed less than 4% of 1-µm MNP. Conversely, CFS treatment showed a significant improvement in the removal of 1-µm MNP from wastewater. At dosages of 0.3-3 mg Al3+/L, the removal of MNPs in wastewater reached 30% and no flocs were observed, while floc formation was visible with increased dosages of 3-12 mg Al3+/L, obtaining MNP removal greater than 90%. CFS in activated sludge with a solids content of 5800 mg MLSS/L registered the highest removal efficiency (95-99%) even for dosages of 0.3-60 mg Al3+/L and pH dropping to 5. However, activated sludge showed extremely high removal efficiency of MNPs (97.3 ± 0.9%) even without coagulants. The large, dense flocs that constitute activated sludge appear particularly efficient in capturing 1-µm MNPs during the sedimentation process even in the absence of coagulants.
Mots clés
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Eaux d'égout
/
Polluants chimiques de l'eau
/
Élimination des déchets liquides
/
Eaux usées
/
Floculation
/
Cytométrie en flux
/
Microplastiques
Langue:
En
Journal:
Chemosphere
Année:
2024
Type de document:
Article
Pays de publication:
Royaume-Uni