stormwater in Paris megacity Robin TREILLES* 1 , Johnny GASPERI 1 , - - PowerPoint PPT Presentation

Macro and microplastics in stormwater in Paris megacity

1Laboratoire Eau, Environnement, Systèmes Urbains (LEESU) 2Direction des Services de l’Environnement et de

l’Assainissement du Val-de-Marne (DSEA)

3Service public de l’assainissement francilien (SIAAP)

*robin.treilles@enpc.fr

µMED International conference on microplastic pollution September 15th/18th 2019 Robin TREILLES*1, Johnny GASPERI1, Mohamed SAAD1, Alain RABIER2, Jérôme BRETON2, Vincent ROCHER3, Sabrina GUERIN3, Bruno TASSIN1

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µMED International conference on microplastic pollution – September 15th/18th 2019

Introduction: plastics in urban waters

Stormwater retention pond

Atmosphere Drinking water

Water reservoir Water treatment

Airborne emissions

Industrial and domestic use

WWTP Domestic wastewater Industrial wastewater

Waste water Sources

Combined sewer

• verflows

* Combined network ** Separative network

Sludge Agricultural fertilizer Environment +++ +++++ +++ ++ ++ Effluents

Stormwater

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µMED International conference on microplastic pollution – September 15th/18th 2019

Introduction: plastics in urban waters

Stormwater retention pond

Atmosphere Drinking water

Water reservoir Water treatment

Airborne emissions

Industrial and domestic use

WWTP Domestic wastewater Industrial wastewater Stormwater

Waste water Sources

Combined sewer

• verflows

* Combined network ** Separative network

Sludge Agricultural fertilizer Environment +++ +++++ +++ ++ ++ Effluents

Plastic fluxes and contribution from stormwater ?

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µMED International conference on microplastic pollution – September 15th/18th 2019

Methods: sampling site

Paris

Marne

Runoff water at the Sucy-en-Brie catchment

• utflow (DSEA Val de Marne)

Macrowaste are collected from two grid refusals (6 and 1 cm) once per month. Microplastics are collected during rain events.

Flowrate (m3/s)

12/03/18

Time

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µMED International conference on microplastic pollution – September 15th/18th 2019

Characteristics of the Sucy-en-Brie catchment

Runoff water at the Sucy-en- Brie catchment outflow 1 km

Catchment Surface (km2) Runoff Coefficient (%) Land use Inhabitants Sucy-en- Brie 2.28 21 Mainly a residential area with large number of multi-

• ccupancy family

houses, limited commercial activities ~ 20 000

Macrowaste (> 1 cm) and microplastics (> 50 µm) in stormwater of Sucy-en-Brie 5

µMED International conference on microplastic pollution – September 15th/18th 2019

Methods: macrowaste in stormwater of Sucy-en-Brie

• 1. Debris from the

runoff water are collected from two grid refusals (GR1 6 cm and GR2 1 cm)

• 2. Samples are

weighted

• 3. Incubation at 40°C

during 10 days

• 4. Debris are sorted

and classified

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µMED International conference on microplastic pollution – September 15th/18th 2019

Methods: microplastics in stormwater of Sucy-en-Brie

Collector Samples Plankton net

• 80-100L of runoff water are collected upstream of the

grid refusals during rain events for microplastic analysis.

• This water is then filtered with a 80 µm net and

microplastics are analyzed.

Flowrate (m3/s) 0.6 0.4 0.2

12/03/18

Time

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µMED International conference on microplastic pollution – September 15th/18th 2019

Methods: microplastics in stormwater of Sucy-en-Brie

Filtration on metal filter Ø=90 mm ; porosity 10 µm < 1 mm > 5 mm 1-5 mm Sieving Particles > 5 mm Particles > 1 mm Particles < 1 mm 1 4 2 Filter after SDS + digestion 3 SDS C = 3.5 g.L-1 T = 40°C t = 24 h 300 rpm H2O2 Digestion C = 30% T = 40°C t = 48 h 300 rpm Filter after density separation Density separation NaI (ρ = 1.65 g.cm-3 ) t = 24 h

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µMED International conference on microplastic pollution – September 15th/18th 2019

Microplastics analyses

Fraction 1-5 mm

Visual analysis Stereomicroscope

→ Identification of potential plastics

Spectroscopy FTIR-ATR

→ Nature of the polymer

Caracterisation

Fraction <1 mm (after treatment)

Stereomicroscope

→ Fragments and fibers are counted → Concentrations are estimated

Microspectroscopy FTIR

25 mm 10 cm 20 cm

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µMED International conference on microplastic pollution – September 15th/18th 2019

Results: macrowaste in stormwater of Sucy-en-Brie

Grid refusal 1 (mesh size = 6 cm)

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µMED International conference on microplastic pollution – September 15th/18th 2019

Results: macrowaste in stormwater of Sucy-en-Brie

Grid refusal 1 (mesh size = 6 cm)

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µMED International conference on microplastic pollution – September 15th/18th 2019

Results: macrowaste in stormwater of Sucy-en-Brie

Grid refusal 2 (mesh size = 1 cm)

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µMED International conference on microplastic pollution – September 15th/18th 2019

Results: macrowaste in stormwater of Sucy-en-Brie

➢ Nine waste categories correspond to more than 95 % of all the macrowaste of Sucy-en-Brie (% number of objects accumulated on grid refusals):

13 GR1 (mesh size = 6 cm) GR2 (mesh size = 1 cm)

µMED International conference on microplastic pollution – September 15th/18th 2019

Results: macrowaste in stormwater of Sucy-en-Brie

➢ Macrowaste fluxes after x days of accumulation on both grid refusals ➢ Plastic waste in stormwater of Sucy-en-Brie ~ 10 to 100 mg/m3 ➢ If applied to Paris megacity population: 12 to 40 tonnes of macrowaste/year in stormwater. ➢ July and august correspond to the strongest values (recreational activities, storms ?)

9 days 28 days 16 days 25 days 28 days 24 days 28 days 44 days 21 days

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20 40 60 80 100 120 140 160

Macrowaste flux (mg/m3) Sampling date Runoff water of Sucy-en-Brie

µMED International conference on microplastic pollution – September 15th/18th 2019

Results: microplastics in stormwater of Sucy-en-Brie

Fragments 1-5 mm (MP/L) Fragments <1 mm (MP/L) Fibres <1 mm (MF/L)

Flowrate (m3/s) Time

1 2 3 4 5

12/03/18

1 2 3 4 5

06/11/18

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µMED International conference on microplastic pollution – September 15th/18th 2019

Results: microplastics in stormwater of Sucy-en-Brie

Fragments 1-5 mm (MP/L) Fragments <1 mm (MP/L) Fibres <1 mm (MF/L)

Flowrate (m3/s) Time

1 2 3 4 5

12/03/18

1 2 3 4 5

06/11/18

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Polyethylene 48% Polystyrene 37% Polypropylene 15% ➢ Characterisation

• n

µFTIR (first results):

µMED International conference on microplastic pollution – September 15th/18th 2019

Conclusion

 For macrowaste in stormwater:

 Nine waste categories correspond to more than 95 % of all the

macrowaste of Sucy-en-Brie.

 Macrowaste flux ~ 10 to 100 mg/m3.

 For microplastics:

 Microplastic concentration ranges between 2 and 5 MP/L  Small decrease is observed over time.  More rain events will be studied.

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µMED International conference on microplastic pollution – September 15th/18th 2019

Thank you for your attention! Any questions??? robin.treilles@enpc.fr

Source : www.leyton.com

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µMED International conference on microplastic pollution – September 15th/18th 2019

Results : microplastics in stormwater of Sucy-en-Brie

0,00 2,00 4,00 6,00

1 2 3 4 5 1 2 3 4 5

Concentration MP/L or MF/L

Rain event 1: 06/11/18 Rain event 2: 12/03/18

Fragments 1-5 mm (MP/L) Fragments <1 mm (MP/L) Fibres <1 mm (MF/L)

Flowrate (m3/s) Time

1 2 3 4 5

12/03/18

1 2 3 4 5

06/11/18

➢ Comparaison with other studies : ➢ Characterisation on µFTIR (fragments, first results) :

Polyethylene 48% Polystyrene 37% Polypropylene 15%

2 – 29 MP/L Grand Paris (Dris et al., 2018) 4,9.10-1 - 22,9 MP/L Danemark (Liu et al., 2019)

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