Transport and Fate of Microplastic Particles in Wastewater Treatment Plants

Transcription

1 Transport and Fate of Microplastic Particles in Wastewater Treatment Plants Steve A. Carr, Jin Liu*, Arnold G. Tesoro San Jose Creek Water Quality Control Laboratory, Sanitation Districts of Los Angeles County, 1965 South Workman Mill Road, Whittier, CA 90601, USA *Corresponding author Phone: , ext. 3072; fax: ; Appendix A. Supplementary data Figure S1 Selected examples of micro-solids extracted from cosmetic products in the typical size range of μm. Figure S2 (a) Some MPPs ( μm) collected in the surface filtering assembly. (b) White or transparent MPPs ( μm) collected in the sieves at WWTP. (c) MPPs in Figure 3(i) visible with the naked eye. S1

2 Figure S3 (a) Bio-residues collected in the 45 μm sieve at WRP 6 when viewed under high magnification, I: Testate Amoebae, II: filamentous bacteria, III: rotifer. (b) Filamentous bacteria in 45 μm sieve residues at WRP 6. (c) Comparative fabric fibers (lint type taken from domestic washing machines) using similar magnification for (b). Figure S4 Bench-scale gravity filter. S2

3 Figure S5 Effluent filtration using stacked sieves at a WRP. Surface filtering assembly To construct the surface filtering assembly, two 5.5 -wide strips were cut from a 4' roll of 125 μm stainless steel mesh (TWP, Inc., Berkeley, CA 94710, USA). Three 1 -wide polyethylene ring supports were cut from a 6.5 -diameter (¼ inch thick) polyethylene cylinder. The supporting struts were constructed from bamboo rods (¾ -diameter and 8'-long) (Frank s Cane and Rush Supply, Huntington Beach, CA 92647, USA). These poles were light weight and had the structural rigidity required to support the filtering assembly. The ring supports were then attached to the bamboo rods using screws and bolts. This assembly formed a scaffold on which hemi-cylindrical scoop was constructed. The two (5.5 4') stainless steel mesh strips were wrapped around the cylindrical framework and poles. The mesh was securely attached to the circular rings using small nuts and bolts, and to the bamboo poles with copper wire. Both ends of the filter were capped with a combined fitting made of half a diameter plastic disk and half a 6.5 -diameter 125 μm mesh. This hemi-cylindrical filter was then S3

4 joined at each end to an 8' articulated bamboo extension pole using stainless steel bolts. Each arm, in turn, was connected to a ¾ PVC pipe tee through which a horizontal 8.5'-long and ½ - diameter steel crossbar was threaded. The entire assembly was secured to two 10'-long and ¾ - diameter aluminum poles attached to hand rails at the outfall. To regulate buoyancy, support strings and floats were incorporated onto the assembly to facilitate fine adjustments of filter immersion depth (¾ -2 below the effluent surface) and correct for daily flow variations. For the later sampling events, the 8'-length of the skimming assembly was shortened to 4', in order to accommodate the narrower channels. Deployment and recovery of the filtering assembly could be performed in <5 minutes. Figure S6 The 8 -length filtering assembly for skimming the surface of effluent at WRP 2. S4

5 -Expanded View- Figure S6 The 8 -length filtering assembly for skimming the surface of effluent at WRP 2. Figure S7 The 4 -length surface filtering assembly deployed at WRP 3 and 7. FTIR Measurements The FTIR instrument was equipped with a high-throughput single reflection ATR unit (ATR PRO ONE Single-reflection ATR Accessory) using a crystal. MPPs or bio-residues in each sample were washed thoroughly with DI water in a 45-μm sieve pan, then air dried for a period of 24 h at room temperature. MPPs or bio-residues used for the FTIR analysis were taken from each sample and placed on the ATR crystal with a micro spatula. Standard fluorescent polyethylene microbeads (red, μm) from Cospheric were used for the FTIR analysis without further purification. S5

6 T (%) T (%) (a) Fluorescent polyethylene microbeads (red, μm) from Cospheric (b) White mica from the toothpaste S6

7 T (%) T (%) (c) Blue MPPs from the toothpaste (d) Bio-residues collected in the 45 m sieve at WRP S7

8 T (%) T (%) (e) Blue MPPs collected in the sieves at WWTP (f) White MPPs from a facial scrub product Figure S8 FTIR Spectra of (a) fluorescent polyethylene microbeads (red, μm) from Cospheric, (b) white mica from the toothpaste, (c) blue MPPs from the toothpaste, (d) bioresidues collected in the 45-μm sieve at WRP 6, (e) blue MPPs collected in the sieves at WWTP, (f) white MPPs from a facial scrub product. S8