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Sustainable decentralized water systemsPart B: Technical solutions

International Conference

Smart Urban Regeneration & Smart City DevelopmentMarch 8, 2019Seoul, Korea

Prof. Jan Hoinkis & Edgardo KurzCenter of Applied Research (CAR)

Karlsruhe University of Applied Sciences

Outline

1. Challenges

2. Concept of decentralized urban water reuse

3. Membrane technology

4. Previous projects

5. Towards project implementation

02.03.2019 1

02.03.2019 2

1. Motivation

„Water quantity and quality is the biggest

environmental issue that we face in the21st century“

Christie Whitman / U.S. Environmental Protection Agency

Source: meerkat21.files.wordpress.com

02.03.2019 3

Source: Population Action International https://pai.org/

South Korea is regarded as water stressed country

1. Motivation

▪ Fast-growing population and increasing urbanization in Asia ▪ Growing demand for water▪ Water stress on existing water sources in South Korea ▪ Quality degradation (primary source: river basins around 90%)

Challenges in South Korea

▪ Extensive pollution of fresh water sources

▪ Marginal renewable freshwater resources per person

▪ Abundant but unevenly distributed rainfall

▪ Risks associated with climate change

Source: http://blogs.worldbank.org/ Source: https://arad.co.il

82.5% of population live in urban areas

4

1. Motivation

Solutions

• Water saving practices

• Use of alternative water sources, e.g. seawater

• Rainwater harvesting

• Efficient water treatment and reuse

• Use of renewable energies to drive the treatment processes

12 Mörk desalin® | Puy | 23.04.2012 |

Project in Zanzibar

Grand Opening of the first Mörk desalin® installation

Source: www.moerkwater.com

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1. Motivation

Membrane technology can significantly contribute!

Solutions

• Water saving practices

• Use of alternative water sources, e.g. seawater

• Rainwater harvesting

• Efficient water treatment and reuse

• Use of renewable energies to drive the treatment processes

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2. Concept for decentralized water reuse

Source separation of household wastewater

Kitchen

waste

Treatment

C-reductionDisinfectionNutrients recoveryElim. micropollutantsStabilization

C-reductionDisinfectionP-eliminationStabilization

✓ Optimized treatment process✓ Easier resource recovery✓ Facilitate water reuse strategies

Source: Larsen et al. Urban

Planet 2017, (352) 6288

7

2. Concept for decentralized water reuse

Concept 1

Kitchen

waste

8

Forwardosmosis

Grey-water

AnaerobicMBR

Black-water

Reverseosmosis

UV

Biogas

Renewableenergy

Nutrientreuse

Drinkingwater

Rainwaterinfiltration

2. Concept for decentralized water reuse

Concept 2

3. Membrane technology

Basic principle of membrane technology

9

£ 1mm

Particle

Bacteria

Permeate

Viruse

Ion Feed Concentrate

2

- -

+ +

▪ Mechanical separation of gaseous or liquid streams

▪ Separation process purely physical → membrane functions as barrier

▪ Feed stream separated in permeate and concentrate fractions

Overview of pressure-driven membrane processes

10-4 10-3 10-2 10-1 1 10 100

Particle / Molecule Size [mm]

Pressure difference

[bar]

1

10

100

Nano-

filtration

Reverse

osmosis

Microfiltration

Filtration

Ultrafiltration

Bacteria Viruses

Pigments

Emulsions

Cells

Salt ions

Sugar

Proteins

10

3. Membrane technology

Typical technical membrane units

RO modules

FO modulesSource: www.blue-tec.nl

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3. Membrane technology

Feed

Drivingforce:Membrane:NF,RO:Dp Dense,hydrophilicMD:DT Porous,hydrophobicED:DE Ionexchange

Concentrate

Membranemodule

PermeatePermeateReconcentration

unitTreatedwater

Drivingforce:Membrane:FO:Dc Dense,hydrophilic

4

Forward Osmosis (FO)

Draw solution (salt solution)

RO

3. Membrane technology

Advantages

▪ Lower energy consumption

▪ Low fouling propensity with upfront FO

▪ Combination process can be used for brine

concentration

Challenges

▪ Membrane cost (→ Capital cost)

▪ Second treatment needed (→ Capital/operating cost)

FO desalination plant at Al Khaluf, Oman

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3. Membrane technology

Comparison of FO Technology vs. conventional reversed osmosis

An MBR is a combination of a bioreactor and membrane technology (microfiltration

0.1-0.5 mm, ultrafiltration 0.05-0.1 mm)

Membranes are submerged in bioreactor

Effluent

Bioreactor and membranes are separate

Feed

Air/Biogas

Bioreactor

Feed

Effluent

Air/Biogas

Bioreactor

Aerobic or anaerobic14

3. Membrane technology

Membrane bioreactor (MBR)

Source: www.hitachi-pt.com/mbr/mbr_outline.html 15

3. Membrane technology

Comparison of MBR Technology vs. Conventional Bioreactors

Advantages

▪ High efficiency in degradation of organic compounds

▪ No clarifier needed

▪ Treated water free of turbidity and negligible

germ level → Reuse!

Challenges

▪ Membrane cost (→ Capital cost)

▪ Aeration cost (→ Operating cost)

Typical commercial submerged MBR modules

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www.kubota.com

3. Membrane technology

4. Previous projects

LIWATECLaundry Innovative Wastewater

Recycling Technology

www.liwatec.de

University of Applied Sciences Karlsruhe, GermanyPanten, Textilservice Klingelmeyer, Darmstadt, Germany

EU Life Environment

17

LIWATEC – Motivation

• High costs of freshwater and for wastewater discharge

• More stringent discharge limits for wastewater

(e.g. heavy metals, organic matter)

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4. Previous projects

LIWATEC – Wastewater reuse concept

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4. Previous projects

LIWATEC – MBR from pilot to large scale unit

Lab-scale Small-scale Industrial scale

Volume 0.1 m3 5 m3 125 m3

Membrane area 0.5 m2 28 m2 480 m2

Capacity 0.2 m3/d 10 m3/d 150-200 m3/d

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4. Previous projects

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5. Towards project implementation

Forwardosmosis

Grey-water

AnaerobicMBR

Black-water

Reverseosmosis

UV

Biogas

Renewableenergy

Nutrientreuse

Drinkingwater

Rainwaterinfiltration

1. Forward osmosis (FO) technology

2. Anaerobic MBR (AnMBR)

3. Sustainable energy supply →

Biogas/CHP + TEG & PV

4. Disinfection (UV)

5. Rainwater harvesting (rooftop of apartment blocks)

6. Groundwater management (e.g. rainwater infiltration)

7. Irrigation water for gardening

Holistic project implementation

Integration of management strategies and adequate technologies for thecharacteristic water streams to maximize the water reuse potential:

Thank you for your attention!

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02.03.2019 23

Source: Choi et al. Water 2017, 9, 717

1. Motivation

▪ Urban population increase promoted by industrialization and urbanization▪ Growing demand for water▪ Water stress on existing water sources in South Korea ▪ Quality degradation (primary source: river basins around 90%)

Population growth Water demand increase