Risk assessment of Landfills and their Impact of Surface Waters

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Risk assessment of Landfills and their Impact of Surface Waters

Skov Nielsen, Sanne; Tuxen, Nina; Roost, Sandra; Pedersen, John; Bjerg, Poul Løgstrup; Sonne, Anne Thobo; Korsgaard, Trine; Pedersen, Jørn K.; Broch, Helle; Ulstrup, Alice; Larson, Helle; Rud Larsen, Henrik; Olsen, Claes ; Bondgård, Morten; Aabling, Jens

Publication date:

2015

Document Version

Peer reviewed version

Link back to DTU Orbit

Citation (APA):

Skov Nielsen, S., Tuxen, N., Roost, S., Pedersen, J., Bjerg, P. L., Sonne, A. T., ... Aabling, J. (2015). Risk assessment of Landfills and their Impact of Surface Waters [Sound/Visual production (digital)]. 13th International UFZ-Deltares Conference on Sustainable Use and Management of Soil, Sediment and Water Resources, Copenhagen, Denmark, 09/06/2015

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Risk assessment of Landfills and

their Impact of Surface Waters

Sanne Skov Nielsen, Nina Tuxen, Sandra Roost, John Pedersen, Orbicon

Poul L. Bjerg, Anne T. Sonne, DTU Environment, Technical University of Denmark

Trine Korsgaard, Jørn K. Pedersen, Helle Broch, Alice Ulstrup, Region of Southern Denmark Helle Larson, Henrik Rud Larsen, Claes Olsen, Morten Bondgaard, Central Denmark Region Jens Aabling, Danish Environmental Protection Agency

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Background: Municipal Landfills

Assumption:

Old landfills are more likely than other contaminated sites to

impact surface waters, particularly streams

22. juni 2015 2

300 m

2

_{– 590,000 m}

2

_{, typically 25,000 m}

2

Gravelpits or stream banks

60-70 years old

NH

₄+

Cl

-

Fe

2+

K

+

Ca

2+

COD

• Household waste: Food, plastics,

glass, paint, furniture, paper

• Waste water sludge

Heavy metals _Organic _chemicals

• Chemical waste: Solvents,

gasoline, pesticide containers,

batteries

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22. juni 2015 3

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Concept for Risk Assessment

Tier 0

Automatic GIS Screening

Tier 1

Improved screening

Tier 2

Initial investigation

Tier 3

Field investigations

Tier 4

Total impact

Input Data

Flux measurements Discharge zones Data from other impacts

Surface water samples Conceptual model

2 case studies

for field

investigations

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Tier 2:

Conceptual Model + Initial Sampling

Tier 0

Automatic GIS Screening

Tier 1

Improved screening

Tier 2

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Tier 2: Excisting data for conceptual model

• Source

– Historical records, aereal photos,

old maps ect.

– Previous investigations: Wells,

contaminants, concentrations

– Geometry and site

• Transport

– Groundwater and geology

– Drain pipes

– Surface run off

– All part of conceptual model

• Receptor

– Size of stream

– Flow: discharge, temporal pattern

Thomsen et al., 2012

Source

Transport

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• Models describe leachate transfer pathway(s)

• Contaminant transport depends on

– Shallow hydrogeology – Distance to surface water – Water table in waste? – Configuration of waste – Drain pipes

Inspired by:

Guide for contaminant investigations on landfills (AVJ) GOI-typologies from Danish EPA

Mågevej Landfill

Lilleskovvej Landfill

Grindsted + Vejen Landfills

Conceptual Models for Landfills

No surface water risk

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N

Tier 2: Conceptual models - Typologies

Lille Skovvej Landfill

Mågevej Landfill

Clay

Sand

Wetland

Landfill Type E

_{Landfill Type F}

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• Why sample groundwater,

when you can sample

surface water?

– Ground water sampling: Wells,

pumps, risk of wrong

placement, dry well …

– Surface water sampling

equiptment: Rubber boots

• Critical points:

– Mixing in stream water

– Several plumes or discharge

points

– Good conceptual model helps

finding sampling point

Tier 2: Initial sampling

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Ammonium and Dissolved Iron in Streams

0.00 0.10 0.20 0.30 0.40 0.50 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 K oncen tr ati on (mg /L ) Afstand (m)

Opløst jern Ammonium-N

0.01 0.10 1.00 10.00 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 K on ce n tr at ion (mg /L ) Afstand (m)

Opløst jern Ammonium-N

Lille Skovvej Landfill

Mågevej Landfill

Distance along stream (m) Distance along stream (m)

Diss. Fe Diss. Fe Con cen tr at ion (mg /L) Con cen tr at ion (mg /L)

Ammonium level in stream exceeds EQS

before landfill

Iron is possibly complexed

EQS

Ammonium level in stream ≈ EQS before

landfill

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22. juni 2015 11

Tier 3: Further investigations

Tier 0

Automatic GIS Screening

Tier 1

Improved screening

Tier 2

Initial investigation

Tier 3

Field investigations

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N

Tier 3: Field Investigations

Lille Skovvej Landfill

Mågevej Landfill

Q

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0.E+00 1.E-06 2.E-06 3.E-06 4.E-06 8 9 10 11 12 13 0 200 400 600 800 1000 1200 qz (m/ s) T20 (° C) Afstand (m) T20 qz (T_bed) A B C

Figur 1: Den målte temperatur i 20 cm’s dybde (T20) i bundsedimentet sammenholdt med de beregnede

grundvandsflux, qz, hvor grundvandstemperaturen er sat til 9 °C (TL), langs Vegen Å på den undersøgte strækning. T20

er vist med blåt og qz med rødt. Placeringen af de 3 betydende grundvandsindsivningszoner, hvor qz oversteg 3*10-6

m/s, er nummereret 1- Grundvandsindsivning, q svarende 3. 3*10-6_{m/s på qz-aksen er fremhævet med en grøn linje.}

0 200 400 600 800 1000 0 200 400 600 800 1000 1200 EC ( µS/ cm) Afstand (m) 12/8/2013 13/8/2013 285 290 295 300 305 310 0 200 400 600 800 1000 1200 EC ( µS /cm ) Afstand (m) 1/7/2013 0 200 400 600 800 1000 0 200 400 600 800 1000 1200 EC ( µS/ cm) Afstand (m) 12/8/2013 13/8/2013

Calc. GW discharge

Electrical Conductivity

Tier 3: Discharge of Groundwater?

Temperature

Calculated GW discharge

Temperature

Electrical Conductivity

Lille Skovvej Landfill

Mågevej Landfill

Distance along stream (m) Distance along stream (m)

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Tier 3: Results from investigations

• Temperature measurements: No direct hydrogeologic contact

• Electrical conductivity shows clear leachate impact but with temporal variability

• Leachate (Fe, Ammonium, NVOC), heavy metals (Cd, As, Ba) and xenobiotics above surface water criteria way downstream landfill

• Most important pathway was drainage pipes, not groundwater

Lille Skovvej Landfill

Mågevej Landfill

• Temperature and EC measurements: 3 discharge zones

• Discharge from sides of stream, not stream bottom

• Heavy metals and xenobiotics below

detection limits in surface water and stream bottom

• Leachate (Fe, Ammonium, NVOC), above surface water criteria

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Tier 4: Total impact on water body

Tier 0

Automatic GIS Screening

Tier 1

Improved screening

Tier 2

Initial investigation

Tier 3

Field investigations

Tier 4

Total impact

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Tier 4: Total Impact on Water Bodies

• Chemical status: EQS

• Ecological status not

considered so far. No direct

measurements on ecology

• Consider the impact from

other sources

Compounds Other sources

Salts and chloride Fertilizers

Roads (de-icing)

”Clean” municipal waste water Nitrate, NVOC,

ammonium

Agriculture Aquaculture

Dissolved iron Anaerobic groundwater

Ochre formed by drainage Xenobiotics and heavy

metals

Waste water (municipal and industrial)

Road run-off

Contaminated sites?

Pesticides Other point sources

Washing stations Agriculture

Mågevej Landfill:

Insignificant impact

Unknown sources of ammonium and iron

upstream of landfill

Lille Skovvej Landfill:

Significant impact

Not only lechate, but also xenobiotics, Ba,

Cd and As

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Conclusions

• Old landfills are important contamination sources

which may deteriorate the chemical status of surface

water bodies, mainly small streams

• Landfills are important contributors on a local scale

but not on catchment scale

• Contaminants of concern are ammonium, NVOC,

heavy metals and xenobiotics

• The tiered approach for risk assessment was a useful

tool developed for improved understanding of a

complex contaminant transport system

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