TY - JOUR
T1 - The occurrence and fate of microplastics in a mesophilic anaerobic digester receiving sewage sludge, grease, and fatty slurries
AU - Chand, Rupa
AU - Rasmussen, Lasse Abraham
AU - Tumlin, Susanne
AU - Vollertsen, Jes
PY - 2021/7/30
Y1 - 2021/7/30
N2 - The mesophilic digester of a wastewater treatment plant serving 790,000 inhabitants was analyzed for incoming and outgoing microplastics (MPs). The annual MP load on the digester was 7326 kg y−1and 1.20 × 1014Ny−1,while the digested sludge contained 4885 kg y−1and 0.85 × 1014Ny−1. The corresponding mean reduction of approximately 30% was though within the variability of the analyzed samples, and size distributions and polymer composition before and after the digester could similarly neither confirm nor deny if MPs were lost in the digester. The load on the digester corresponded to a per capita load of 0.025 g capita−1day−1or 4.14 × 105Ncapita−1day−1. In terms of MP numbers, the values were high compared to most previous studies, which most likely was due to differences in analytical methods, where the present study applied FPA-μFTIRhyperspectral imaging with automatized MP recognition in the size range 10–500μm and ATR-FTIR on all particles in the range 500–5000μm. The polymer composition was quite diverse, with 15 identified polymer types, of which polyethylene and polyester were the most common in the sludge, while the variation in composition was larger in the grease that came from the plant's grease trap and the fatty slurries which came from grease traps in the drainage area. The load on the digester was finally used to demonstrate how especially the determined mass loads can be used to set upper boundaries for specific sources, for example human excretion.
AB - The mesophilic digester of a wastewater treatment plant serving 790,000 inhabitants was analyzed for incoming and outgoing microplastics (MPs). The annual MP load on the digester was 7326 kg y−1and 1.20 × 1014Ny−1,while the digested sludge contained 4885 kg y−1and 0.85 × 1014Ny−1. The corresponding mean reduction of approximately 30% was though within the variability of the analyzed samples, and size distributions and polymer composition before and after the digester could similarly neither confirm nor deny if MPs were lost in the digester. The load on the digester corresponded to a per capita load of 0.025 g capita−1day−1or 4.14 × 105Ncapita−1day−1. In terms of MP numbers, the values were high compared to most previous studies, which most likely was due to differences in analytical methods, where the present study applied FPA-μFTIRhyperspectral imaging with automatized MP recognition in the size range 10–500μm and ATR-FTIR on all particles in the range 500–5000μm. The polymer composition was quite diverse, with 15 identified polymer types, of which polyethylene and polyester were the most common in the sludge, while the variation in composition was larger in the grease that came from the plant's grease trap and the fatty slurries which came from grease traps in the drainage area. The load on the digester was finally used to demonstrate how especially the determined mass loads can be used to set upper boundaries for specific sources, for example human excretion.
KW - Digestion
KW - Fatty slurries
KW - Grease
KW - MP
KW - Sludge
KW - Wastewater treatment plant sludge
KW - Digestion
KW - Fatty slurries
KW - Grease
KW - MP
KW - Sludge
KW - Wastewater treatment plant sludge
UR - https://www.sciencedirect.com/science/article/pii/S0048969721043606?via%3Dihub
UR - http://www.scopus.com/inward/record.url?scp=85111535691&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2021.149287
DO - 10.1016/j.scitotenv.2021.149287
M3 - Journal article
SN - 0048-9697
VL - 798
JO - Science of the Total Environment
JF - Science of the Total Environment
IS - 1 December 2021
M1 - 149287
ER -