Future water management of cities

Research based decision support for urban water system development

Martin Rygaard (mryg@env.dtu.dk)

With help from Sarah, Brudler, Berit Godskesen, Karsten Arnbjerg-Nielsen, Erik Arvin, Linda L. Fang, Borja V. Perez, Benedek Plosz, Anders Damgaard

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EXAMPLE 1Decision support – Technology Development

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ObjectivesScenarios for

implementationof a novelressource recovery

technology

Assess the environmental impact of the

scenarios

Use Life Cycle Assessment as a support tool for the TRENS

developers

1

23

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The scenarios: Implementing TRENS

A Conventional watewater treatment

BAgricultural reuse:Irrigation & Fertilization

90%

10%

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The scenarios: Implementing TRENS

A Conventional watewater treatment

BAgricultural reuse:Irrigation & Fertilization

10 km

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LCA – Method in brief

• Functional unit: 1m3 of influent wastewater

• Life cycle inventory: operating reports for existing processes, databases for infrastructure and modeling of sludge and algal processes (ASM-2d and ASM-A)

• Impact assessment: International Reference Life Cycle Data System (ILCD 2011)

• Uncertainty analysisContribution analysis

Pertubation analysis(sensitivity ratios)

Uncertainty assessment

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LCA – Method in brief

• Functional unit: 1m3 of influent wastewater

• Life cycle inventory: operating reports for existing processes, databases for infrastructure and modeling of sludge and algal processes (ASM-2d and ASM-A)

• Impact assessment: International Reference Life Cycle Data System (ILCD 2011)

• Uncertainty analysisContribution analysis

Pertubation analysis(sensitivity ratios)

Uncertainty assessment

J Clavreul et al., 2014 Env. Mod. Software

EASETECH

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Included processes

Processes

A, B WWTP Construction

A, B WWTP Operation

A, B Discharge to sea

A, B Waste incineration

A, B Emissions to air

A, B Biogas combustion

A, B Combustion in flare

B TRENS

B Pipeline

B Fertilizer substitution

B Use-on-land

BAgricultural reuse:Irrigation & Fertilization

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Results

Scenario A: Without TRENS

Scenario B: With TRENS sidestream irrigation & fertigation

Marine Eutrophication

Human/Eco Toxicity

1 PE

x kg

coal/p/y

L. L. Fang et al. in revision for Water Research

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BAgricultural reuse:Irrigation & Fertilization

Process contributions scenario B

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EXAMPLE 2Decision support – Climate adaptation

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Cloudburst Management Plan for Nørrebro

“Green“ stormwater management:

• Decouple rain water from sewer

• Discharge of water via new flow routes – on the surface

• Represent asset in themselves

Transformation of roads, parks

and public areas

Sourc

e:

Konkre

tisering a

f Skybru

dspla

n N

ørr

ebro

(H

OFO

R, Københavns K

om

mune &

Ram

bøll 2

013)

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Results for the “green“ and “grey“ scenario

0

2000

4000

6000

8000

10000

12000

14000

PE /

2.6

km

2

"Green"scenario

"Grey"scenario

Slide: Sarah Brudler

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EXAMPLE 3Decision support – Softening in Copenhagen

Drinking water softening will save households approx 80 SGD/person/yr

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(Godskesen et al. J.Env.Man. 2012)

-30%

-60%

Change in hardness levels

Assessing impacts of softening

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1.0

1.5

1.5

2.0

2.0

2.0

2.5

2.5

2.5

3.0

3.0

3.5

3.5

4.0

4.5

Calcium (mg/l)

0 20 40 60 80 100 120 140

Flu

oride (

mg/l)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

63.25

53.8311.0

25.0

33.018.005.1exp

SDMF

CaF

Unit: DMF-S

Softening AB

CD

E

A: Typical Danish groundwaterB: Softened groundwaterC: Typical desalinated and remineralized waterD: RainwaterE: Danish groundwater (high fluoride content)

Relation based on Danish water quality data: (Ca: 31.4-162.3 mg/l; F: 0.06-1.61 mg/l)

(Based on Bruvo et al., J. Dental Res., 2008)

Advice for the Danish Health Inspectors

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EXAMPLE 4Decision support – Alternative water ressources

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0

0.5

1

1.5

2

Groundwater based supply Desalination

En

vir

on

men

tal im

pact

(m

PET/

m3

)

DK Energy mix 2012

DK Energy mix target 2020

A shift towards treatment intensive water supply

(Rygaard et al., Sci.Tot.Env., 2014)

Environmental evaluation of scenarios for future water systems

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Future sustainable

watersystems

Economy

Health riskEnvironmental

impact

Freshwaterimpacts

Concrete / PE pipe production

Concrete production

TruckExcavation &

disposal of soil

Truck

Cleaning

Cleaning

ExcavationTreatment/ recycling

TreatmentExcavationExcavation &

disposal of soil

Grass seed / tree seedling

productionTruck

Mowing & disposal of

grass / cuttingsCompostingExcavationSowing / planting

Clay / gravel production

Truck LandfillingExcavationExcavation

Gravel / cobblestone production

Truck Cleaning LandfillingExcavationExcavation &

disposal of soil

Landfilling / composting /

treatmentExcavation

Excavation Landfilling

Pipes

Channels

Planted areas

Drainage

Paved areas

Decommissioning of park areas

Lowering of park areas

Manufacturing Transport Construction MaintenanceDe-

commissioningDisposal

(Brudler, 2015)