Microplastic ic poll llution and wastewater treatment: State of - - PowerPoint PPT Presentation

Microplastic ic poll llution and wastewater treatment:

State of knowledge and future dir irections

Tom Stanton BSc, MRes Email: thomas.stanton@nottingham

• What are microplastics?
• Microplastics and the wastewater treatment process (1)
• Microplastics and the wastewater treatment process (2)
• Identification of Microplastics
• What am I doing?

Overview

Microplastic Particles:

• Particles of synthetic plastic material no

greater than 5 mm in their largest dimension.

• Synthetic textile fibres (Napper and Thompson, 2016).

500 µm 1 mm

What is a microplastic?

Figure 1: An illustration of the fate of microplastic particles of different densities during the wastewater treatment process Microplastics that are dense enough to settle are periodically removed from settling tanks along with other settled solids Microplastics that float are scraped from the surface of settling tanks before being mixed with the settled solids Microplastics that remain in suspension may escape further treatment filters, such as those used in tertiary treatment plants, contaminating WWTP effluent and being introduced directly to a WWTP’s receiving waters.

Influent WWTP facility Outflows and

• utputs

Emission to receiving waters Emission to Land

Figure 1: An illustration of the fate of microplastic particles of different densities during the wastewater treatment process Microplastics that are dense enough to settle are periodically removed from settling tanks along with other settled solids Microplastics that float are scraped from the surface of settling tanks before being mixed with the settled solids Microplastics that remain in suspension may escape further treatment filters, such as those used in tertiary treatment plants, contaminating WWTP effluent and being introduced directly to a WWTP’s receiving waters.

Influent WWTP facility Outflows and

• utputs

Emission to Land

Microplastics and the wastewater treatment process (1)

Study Microplastic removal from wastewater (%) Treatment level Murphy et al. (2016) 98.4 Secondary Mintenig et

• al. (2017)

97 Tertiary Talvitie et al. (2017) 97 Tertiary Study Dominant size range Liquid fraction Murphy et al. (2016) 598 µm (±89)* Mintenig et al. (2017) 50-100 µm (59%) Talvitie et al. (2017) 20-100 µm (70%) * Dominant size range not expressed. Data presented is instead the mean particle size. Study Dominant polymer Liquid fraction Particles (%) Fibres (%) Murphy et al. (2016) Polyester 81.5 18.5 Mintenig et al. (2017) Polyethylene N/A N/A Talvitie et al. (2017) Polyethylene >70 <30

Microplastics and the wastewater treatment process (1)

Microplastics and the wastewater treatment process (2)

Figure 1: An illustration of the fate of microplastic particles of different densities during the wastewater treatment process Microplastics that are dense enough to settle are periodically removed from settling tanks along with other settled solids Microplastics that float are scraped from the surface of settling tanks before being mixed with the settled solids Microplastics that remain in suspension may escape further treatment filters, such as those used in tertiary treatment plants, contaminating WWTP effluent and being introduced directly to a WWTP’s receiving waters.

Influent WWTP facility Outflows and

• utputs

Emission to receiving waters Emission to Land

WWTP facility

~80% Reused ~20% Disposed of ~18% Incineration ~79% Agriculture <2% ‘Other’ <1% Landfill and ‘other’

Microplastics and the wastewater treatment process (2)

DEFRA (2012)

What don’t we know? Study Dominant size range Liquid fraction Solid Fraction Murphy et al. (2016) 598 µm (±89)* 1342 µm (±519)* Mintenig et al. (2017) 50-100 µm (59%) N/A Talvitie et al. (2017) 20-100 µm (70%) N/A * Dominant size range not expressed. Data presented is instead the mean particle size Study Liquid fraction Solid fraction Dominant polymer Particles (%) Fibres (%) Dominant polymer Particles (%) Fibres (%) Murphy et al. (2016) PES 81.5 18.5 PES N/A N/A Mintenig et al. (2017) PE N/A N/A N/A N/A N/A Talvitie et al. (2017) PE >70 <30 N/A N/A N/A

Microplastics and the wastewater treatment process (2)

Why should we care?

Surface runoff

Microplastics and the wastewater treatment process (2)

Ingestion and bioaccumulation

Why should we care?

Microplastics and the wastewater treatment process (2)

Transportation

Lwanga et al. (2017) Maaß et al. (2017)

Why should we care?

Microplastics and the wastewater treatment process (2)

Identification of Microplastics FTIR Spectroscopy

IR source IR detector Crystal Sample IR source IR detector Sample IR source IR detector Sample

ATR-FTIR spectroscopy (a) Reflectance and (b) transmittance FTIR spectroscopy (a) (b) Illustrations from Wang (2012)

Identification of Microplastics FTIR Spectroscopy

FPA-FTIR spectroscopy Tagg et al. (2015)

What am I doing?

Reflectance FTIR microscopy and microplastic analysis

PerkinElmer Inc. (2015)

What am I doing?

Microplastics in soils

Rillig et al. (2017)

What am I doing?

Microplastics in the atmosphere

Dris et al. (2016) Dris et al. (2015) Dris et al. (2017)

What am I doing?

0.25 mm 0.04 mm 0.06 mm 0.06 mm 0.08 mm

Microplastics in the atmosphere

(a) (b) (c) (d) (e) Reflectance FTIR spectra of five brightly coloured particles observed

• n filter papers from the vacuum filtration of atmospheric deposition

collected across the University of Nottingham’s UK campuses. The red bands correspond to the wave ranges used by Löder et al. (2015) in their identification

• f

microplastic particles using FPA-FTIR spectroscopy.

What am I doing?

Microplastics in the atmosphere

What can be done?

What can be done?

1)

Can the WWT industry monitor microplastic pollution alongside chemical pollutants?

2)

Do different tertiary treatment methods influence effluent microplastic loads?

3)

Can microplastics be removed from biosolids, and how can they then be disposed of?

Thank you! Any questions?

Email: thomas.stanton@nottingham.ac.uk

Please ask for a list of references