Collecting River Litter in Watersheds: a blueprint

Gijsbert Tweehuysen / Yvon WolthuisWaste free Waters / ISI

June 2013

The overall picture

Litter is an emission!

“managed”residue (landfill)

Ecological impacts:Exhaustion of resources and

Emissions (gasses, liquids and solids)

neededgoods

recovered/recycled

waste

collectedwaste

consumption/use

addedproduct

post-usewaste

fulfilledneeds

unfulfilledneeds

resources

Circular economy: cost/profit driven

Litter is an emission of inert solids

• Litter-emissions are different from “known/familiar” chemical or gaseous emissions.

• Litter is an emerging global ecological problem and there is no adequate legal framework to deal with it.

• Detection/sampling requires a different scale– Detection of chemicals in water: microgrammes per liter– Detection of solids in water: grammes per 1000 m3

• Hardly any methods for detection and no standards for emissions of (non-toxic or inert) solids in water.

• Plastics dominate litter emissions• Plastics behave different in water compared to minerals

Litter can be emitted from every stage of the present and future (circular) economy

• Pre-production materials (pellets)• Lost products/parts (broken car parts)• Post-use products (littered beverage pack)• Collected products (hygiene products from

wwt-plants)• Recycled products (scrap)• Landfilled products (picked by birds)

• The (circular) economic system leaks!

Lighter solids will be transported by water

• Results Meuse sampling (Mosa Pura):– Plastics are dominant– Large and small fragments– Floating, suspended and sinking– Hydraulic/meteorological conditions are relevant– Multiple sources– Broad range of materials– Contaminated and mixed– Mixed with organic/natural materials

Found concentration of items/km2

in upper part of the water column (0 – 70 cm)

Items per km2 (surface and suspension together)

0

10.000

20.000

30.000

40.000

50.000

60.000

70.000

80.000

1 2 3 4 5

totaal

flex

rigid

Suggests a relationship with throughput (298, 125, 0, 113, 113 m3/s)

totalflexible

rigid

80.000

70.000

60.000

50.000

40.000

30.000

20.000

10.000

0

Items larger and smaller than 25 mm

Number of items caught

0

100

200

300

400

500

600

surface suspension

Large and small

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

surface suspension

Majority of items (± 75%) are “small” macroplastics (between 3,2 mm and 25 mm)

> 25 mm (large)< 25 mm rigid< 25 mm flex

surface suspension surface suspension

600

500

400

300

200

100

0

100%

0%

90%80%70%60%50%40%30%20%10%

Surface vs. Suspension

Surface

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1 2 3 4 5

Suspension

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1 2 3 4 5

More rigidson the surface

More flexiblesin suspension

rigidflexible

100%

0%

90%80%70%60%50%40%30%20%10%

100%

0%

90%80%70%60%50%40%30%20%10%

Items surface vs. suspensionper km2

0

10.000

20.000

30.000

40.000

50.000

60.000

70.000

Surface per km2 Suspension per km2/m3

totaal

flex

rigid

More items on surface,most rigids

Less items in suspension,most flexibles

totalflexible

rigid

70.000

60.000

50.000

40.000

30.000

20.000

10.000

0surface suspension

Number of items transportedtowards the sea

Number of items per hour

0

5.000

10.000

15.000

20.000

25.000

30.000

35.000

1 2 3 4 5

• Average: 15.127 items/hr– Flexible: 6.079 items– Rigid: 9.049 items

• Maximum: 30.387 items/hr– Flexible: 8.417 items– Rigid: 21.970 items

• Conditions:– Water velocity: ± 3 km/hr– Width river: 150 m– Only top 70 cm

totalflexible

rigid

10.000

35.000

30.000

25.000

20.000

15.000

5.000

0

From source to sink

The most promising approach for river litter is aimed at it’s sources

River litter sources:1. Fly-tipping and illegal dumping in the flood

plain2. Run-off from streets and roadsides in the

catchment area3. Sewage overflows to rivers and tributaries4. Industrial spills (pellets and scrap)

Ultimate destinations

• Sinks:– Land (waste in remote places on land)– River bottom and sediment (empty Meuse

bottom)– Beaches (remote beaches)– Sea bottom (deep sea pictures)

In the meantime:

• Physical effects (e.g. on biota)– Microplastics (< 1 mm): plankton and mussels– Mesoplastics (< 5 mm): smaller fish and birds (Fulmars)– Small macroplastics (< 25 mm): larger fish and birds

(Albatrosses)– Large macroplastics (>25 mm): bigger fish and marine

mammals (whales)

• Toxicological effects (delivering POP’s into food chain)• Impacting ecosystems on seafloor• Impacting recreational, agricultural, economic value of

floodplains and beaches• Endangering use of waters (entangled boat screws and

blocked cooling systems)

Catch litter before it’s gone.

• At sea litter is too dispersed to catch!

• The river is the last interception place• Catch closer to the source is better• Catch emissions at emission points is best• Catch diffuse emissions (fly-litter) in tributaries• Prevent emission is ultimate

• Refrain from using “uncatchables” (< 1 mm)(microbeads in cosmetics)

Characteristics of river litter

Characteristics of river litter

To catch river litter, these characteristics are relevant:

• Size• Material• Surface to Volume ratio (s/v ratio)• Buoyancy

Characteristics of river litter

• Size:

– Micro < 1 mm• Not visible with naked eye

– Meso from 1- 5 mm (“new” category)• Cannot be “picked”

– Macro-small from 5 - 25 mm• Difficult to pick, • small products or fragments from original products

– Macro-large > 25 mm• Very visible, can be picked

Characteristics of river litter

• Material:

– Non-plastics:• Metal• Glass• Paper/board• Ceramic• Natural materials and textile fibers

– Plastics:• PE (LD, LLD, HD), PP, EVA (sw < 1)• PET, PC, PA, ABS, PUR, PS, PVC, rubbers (sw > 1)

– Combinations• PE insulated electrical wire

Characteristics of river litter

• Shape: surface to volume ratio (s/v-ratio)

– High: • Extruded film and foil; thin walled, flexible plastics

– Plastic bags and wrappers

– Average: • Thicker extruded/thermoformed products and films

– PS coffeecups, foodtrays• Thin walled injection moulded products

– buttercups

– Low: • Most rigid injection moulded or thick extruded products

– Plastic pellets, bottle caps– PP or PVC pipes or fragments– Cotton butt sticks

Characteristics of river litter

• Buoyancy

– High:• Closed hollow products (PET bottle)• Closed-cell foams (EPS, PUR-foam, PE-foam)• Most lighter plastics (sw < 1) with low s/v ratio

– PE, PP

– Neutral:• Contaminated products (sand filled PE bag)• Most plastics with high s/v ratio

– Low: • Most heavier plastics (sw > 1) with low s/v ratio

– PET, PS, PA, PUR, PVC, PC

Some consequences:

• Size determines collection tools and equipment

• Material determines the actual or potential toxicity of littered products and revalorisation options

• Shape determines the behaviour of litter in moving water and whether litter is deposited on banks or in vegetation

• Buoyancy determines the place of litter in calm waters

Approach towards a solution of the river litter problem:

Before litter gets in the water:

• Stop using products, e.g …– microplastics in cosmetics (Beat the Microbeads)– Shopping bags (Ban the Bag)– EPS foam in packaging

• Prevent emissions, e.g …– Leak-proof waste management systems– Anti-littering programs (education at schools)– Technical solutions at water treatment plants (membrane

filtration)– Emission controlled landfill sites (birds, wind)

• Clean-up campaigns, e.g …– Nederland Schoon– Schone Maas Limburg– My Beach

When litter is in the water:

• On surface:– Deflection booms– Floating litter trapsBut: obstructing river navigation

• In water column:– Fences and screens– Nets But: problematic for fish migration and water passage

• On bottom:– Dredging in calm watersBut: Different “business”

Catch what, where and how.

SW: specific weightS/V ratio: surface/volume ratio

Floating:High buoyancy

orSW < 1 g/m2 and

small s/v ratio

< 1 mmmicroplastics

1 - 5 mmmesoplastics

5 - 25 mmmacroplastics

> 25 mmmacroplastics

Sinking:Low buoyancy

orSW > 1 g/m2 and

small s/v ratio

Suspended:Neutral buoyancy

orSW ≈ 1 g/m2 and

high s/v ratio

Prevent use orcatch at

treatmentplant

Prevent use orcatch at

treatmentplant

Catch atemission

point

Catch at surfacein tributaries

or non-navigatedrivers

Catch at surfacein tributaries

or non-navigatedrivers

Prevent use orcatch at

treatmentplant

Catch at surface(sw < 1) in

shallow water orclean up

before enteringwater

Catch at surface(sw < 1) in

shallow water orclean up

before enteringwater

Catch atemission

point

Catch atemission

point

Recoverfrom dredged

sediment

Clean up beforefragmentationand entering

water and recoverfrom dredged

sediment

Conclusions and suggested approach

Prevent emissions is ultimate

• Circular economy should be leak-proof• Develop “anti-littering” campaigns and attitude

• Facilitate any waste management system that prevents emissions, also financially

Catch microplastics(< 1 mm)

• Stop using microplastics when possible• Filter at source (e.g. washing machines)• Filtration at waste water treatment plant

• It is practically impossible to catch microplastics in surface water

Catch mesoplastics(1-5 mm)

• Catch at emission point • Focus on waste water treatment plants• Stop using products that fall apart easily (e.g. EPS)

• Support Clean Sweep initiatives (pre-production pellets)

Catch small macroplastics(5-25 mm)

• Catch rigid floating fraction in tributaries (sw < 1, s/v low)

• Catch flexible floating fraction (sw < 1, s/v high) in tributaries with little turbulence and limited depth

• Catch flexible sinking fraction (sw > 1, s/v is high) in tributaries with some turbulence and limited depth

• Clean up large sinking fraction before it get fragmented and small fragments can reach the waters

Catch large macroplastics(> 25 mm)

• Catch rigid floating fraction (sw < 1, s/v small) on surface in rivers or tributaries

• Collect flexible suspended fraction (s/v high) in tributaries with little turbulence and limited depth, but preferably before entering the water

• Collect sinking flexibles and rigids before entering the water and before they get fragmented

Measures:

Measures which can be taken immediately:

1. Increase public awareness on litter problem2. Strengthen anti-litter behavior3. Develop/expand clean up programs4. Improve performance of water treatment plants:

Focus on micro and meso plastics5. Install floating litter traps preferably in (shallow) tributaries6. Install multiple floating litter traps in rivers (in outside bend)7. Remove sinking litter from sediment by dredging in slow

streaming water

8. Install monitoring program to determine effectiveness of all measures

Floating Litter Traps

litter traps in different situations

Bandalong litter traps

Destination of collected litter

Recovery options

• Litter is dominated by plastics• Plastics are manufactured from oil• Litter can replace “virgin” materials, through

– Material recycling– Chemical recycling (Pyrolysis)– Energy recycling

• Necessary technologies are available

But, limitations for recovery are :

• Many different polymer types in the collected litter • Probably degraded by UV-light • Contaminated with organic matter

But:• Prevention of river litter flowing to the

oceans should be the first objective!Therefore:• Catching litter should have higher priority

than high value recovery!

Mosa Pura: a clean Meuse in 2020

Why not? Let’s go for it!

Information:

Waste Free Waters

• Ir. Gijsbert Tweehuysen

• Mob: +31 (0) 653693382• E-mail: wastefreewaters@hotmail.com• Twitter: @wastefreewaters• Blog: www.wastefreewaters.wordpress.com