CLOSING THE WATER CYCLE, RECOVERING

ENERGY AND RESOURCES IN THE CITIES OF THE FUTURE

Vladimir NovotnyPartner AquaNova LLC, Gloucester, MA

Professor Emeritus Marquette University, Milwaukee, WI Northeastern University,

Boston, MA2012 Kappe Lecture

American Academy of Environmental Engineers and Scientists

© Vladimir Novotny

Cities of the Future – Utopia or Unavoidable Reality

“Urbanites now outnumber their rural cousins – and that’s surprisingly good news for the environment”

“The average New Yorker uses far less water and produces less than 50 per cent of the green-house emissions of the average US citizen” Barley 2010, New Scientist 2785, 32-37

Model of Tianjin Ecocity, China

COF – an international movement towards urban water, energy and resources sustainability

However, there is an urgent need for this and future generations to change

the paradigm of how water, energy and resources are managed in urban

areas.

Population increases and migrationCurrent and future effects of climatic change

Increasing imperviousness of watersheds, more polluted runoff

Excessive use of energyUnbalanced hydrology by groundwater infiltration into sewers

Excessive use of waterCompeting uses of resources

Under Current (4th) Paradigm Urban sustainability is compromised by

Urban Metabolism

A Linear

needs to be

changed to

B Cyclic or Hybrid

Current urban systems are mostly linearExcessive water volumes are withdrawn from mostly

distant surface and groundwater sources Inside the community water is used only once and wastefully

Drinking water used in landscape irrigation for growing grass Only about 5 % of treated potable water is used for drinking

and cooking Great losses of water by leaks and evapotranspiration

Water is transferred underground to distant large wastewater treatment plants The WWTPs use excessively energy, emit carbon dioxide and

often methane which are green house gases The WWTPs remove but rarely recover nutrients for reuse Effluent dominated receiving water bodies after discharge Water short water bodies in the cities

Reduced or no base flow. Streams converted to (combined) sewers or concrete lined

channels with no natural low flow. Excessive energy use and GHG emissions

Courtesy Philadelphia Water Department

Cities must adapt to the impact of global climatic changeHeat-temperature and global climatic changes

Urban heat islandsDisaster risks in urban areas are already severe

and will be more deadly if nothing is doneDroughtFlooding

More frequent and intense catastrophic rainstorms (20 – 50 cm rainfalls) and tidal surges Expected sea level increase (Venice, New Orleans,

Tampa, Galveston, The Netherlands, Bangladesh) Inadequate subsurface urban drainage infrastructureLarge parts of some cities are or will become

inhabitable (Mumbai, Bangkok, New Orleans)

Credit Chicago Tribune and USA Today From IPCC 2011 report

Macroscale (Giant) Footprints of Sustainability

A “footprint” is a quantitative measure showing the appropriation of natural resources by human beings Ecological - a measure of the use of bio-

productive space (e.g., hectares (acres) of productive land needed to support life in the cities, including assimilation of pollution)

Water - measures the total water use on site and also virtual water (usually expressed per capita)

Carbon - is a measure of the impact that human activities have on the environment in terms of the amount of GHG emissions measured in units of carbon dioxide per capita

Imb

ala

nce

Ecological footprintYear World

PopulationAvailable productive land

Ha/person Ac/person

1995 < 6 billion 1.5 3.6

2040 >9 billion <1 2Current ecological footprint

Countries with 1 ha/person or less

Most cities in undeveloped countries

Countries with 2-3 ha/person Japan and Republic of Korea (democratic)

Countries with 3-4 ha/person Austria, Belgium, United Kingdom, Denmark, France, Germany, Netherlands, Switzerland

Countries with 4-5 ha/person Australia, Canada and USA

If the cities in the currently rapidly developing countries (China, India, Brazil) try to reach the same resource use as that in developed countries, conflicts may ensue

Urban water use in some countries

VIRTUAL WATERl/cap-day

Food 1928 Electricity 53-73

liter/kgBeef 15,500 Corn 900Milk 1,000

1 gallon=3.78 liters1 kg = 2.2 lbs

Difference between total on site and domestic uses

In Nairobi (Kenya) and other megalopoli of the developing world urban water use is < 50 liter/capita-day

One Month Supply of Water for Typical Florida Family

45 m3 (12,000 gallon) tank

Weight = 45 tonsCost of water is about

$40-70/month2/3 of cost is to

transport the waterMajor use of expensive

energy (1-2 kWatt/m3)Much of this potable

water is used for landscape irrigation

Picture credit Professor James Heaney, University of Florida

GHG (carbon) Emission by Cities

Top ten countries in the CO2 emissions in tons/person-year in 20081

Qatar Kuwait UAE Aruba Bahrain Luxembourg Australia USA Saudi Arabia

Canada

49 30.1 25 21.7 21.4 21.5 18.6 18.8 16.6 16.3

Selected world cities total emissions of CO2 equivalent in tons/person-year2

Washington DC

Glasgow UK

Toronto CA

Shanghai, China

New York City Beijing China

London UK

TokyoJapan

Seoul Korea

Barcelona Spain

19.7 8.4 8.2 8.1 7.1 6.9 6.2 4.8 3.8 3.4

Selected US cities domestic emissions of CO2 equivalent in tons/person-year3

San Diego CA San Francisco

BostonMA

Portland OR

ChicagoIL

Tampa FL

Atlanta GA Tulsa OK

Austin TX Memphis TN

7.2 4.5 8.7 8.9 9.3 9.3 10.4 9.9 12.6 11.06

1World Bank (2012); 2 Dodman (2009) ; 3Gleaser and Kahn (2008) 2,3 Values include transportation (private and public), heating, and electricity

GHG = Green House Gases (CO2, methane, nitrogen oxides and other gases)

6 citiesEcocities

LID potential

Total energy footprint of citiesPopulation density matters

Qingdao

The Fifth ParadigmGOAL:

WATER CENTRIC SUSTAINABLE AND RESILIENT COMMUNITIES

Three E’s of Sustainability1. ECONOMY Create jobs, income and tax base2. ECOLOGY Protect, restore and build city’ s natural assets and

eliminate pollution 3. EQUITY All residents have an access to economic

opportunities and are not exposed to environmental harms

J. Fitzgerald – Emerald Cities

Vision of the Cities of the FutureThe 5th (Sustainable) ParadigmAn ecocity is a city or a part thereof that balances social, economic and environmental factors (triple bottom line) to achieve sustainable development. A sustainable city or ecocity is a city designed with consideration of environmental impact, inhabited by people dedicated to minimization of required inputs of energy, water and food, and waste output of heat, air pollution - CO2, methane, and water pollution. Ideally, a sustainable city powers itself with renewable sources of energy, creates the smallest possible ecological footprint, and produces the lowest quantity of pollution possible. It also uses land efficiently; composts used materials, recycles or converts waste-to-energy. If such practices are adapted, overall contribution of the city to climate change will be none or minimal below the resiliency threshold. Urban (green) infrastructure, resilient and hydrologically and ecologically functioning landscape, and water resources will constitute one system.

Adapted from R. Register UC-Berkeley Currently 200 Chinese urban developments claim to be ecocity (USA Today)

Definition/Vision of an Ecocity:

4 R

s, 3

Ss

and 2

Ts Reduce, Reclaim, Reuse and Restore - 4

Rs1. Reduce - Water and energy conservation2. Reclaim

1. Treat for safe discharge into environment – TMDL2. Reclaim energy (heat), nutrients

3. Reuse after additional treatment4. 4th R – Restore water bodies as a resource

Separate, Sequester and Store- 3 Ss1. Separate Blue, White, Gray, Yellow, and Black Water2. Sequester GHGs and remove/detoxify toxics3. Store reclaimed water on the surface and/or underground

Toilet to Tap – 2 Ts (is it needed?)o Reclamation with or without 3S for potable reuse

Closing the Cycle

COF Criteria Based on World Wildlife Fund’ One Planet LivingWATER – Reduce water demand by 50% from the

national (state) averageWater conservation (more efficient water fixtures), xeriscape) Using additional sources (stormwater, desalination)

SOLID WASTE – No solid waste to landfillReclamation and reuse

ENERGY – Carbon neutralityMinimization or elimination use of fossil fuelsRenewable energy sourcesPassive energy savings (Energy STAR)Water conservation (reduction of pumping energy, CO2

emissionsEnergy and resource recovery from water, used water

and solidsSUSTAINABLE TRANSPORTATION HEALTHY LIFE AND HAPPINES

Source Steve Moddemeyer

Nested semi-autonomousBuildings

Energy efficient, water saving

Neighborhoods Surface drainage Water reuse (irrigation,

toilets, etc.) Cities

Resource recovery Water Energy Nutrients

Resilient water centric

sustainable ecocity

Renewable Energy

1.4. MW Voltaics array in Sonoma CountyWind turbines in Dongtan

Household voltaicsPassive energy sources

Xeriscape – use of native plants (or not thirsty grasses)With native

plants there is almost no irrigation water use

Aesthetically pleasing

Flagstaff (AZ) landscape

Prairie grass and native flower landscape

Urban Best Management Practices with LID Concepts are an Integral Part of the COFs

Green Roofs

Save energy and store water

Rain gardens

Infiltrate and treat runoff

Porous pavement

Infiltrate, store and treat runoff

Ponds and wetlands

Store, treat and infiltrate runoff

Courtesy City of Seattle

Courtesy of AquaTex Sci. Consulting

Urban Water Body Restoration and Daylighting are Important

Lincoln Creek in Milwaukee Dayligthted Zhuan River in Beijing Kallong River in Singapore

Courtesy CDM

Courtesy PUB Singapore

Courtesy Beijing Hydraulic Research Institute

After

Before

After

Photos V. Novotny

Water centric (LID) drainage in ecocities’ 1st order streams

Solar Panels

Zhiangjiawo, PRC. Credit Herbert Dreiseitl ,Hammarby Sjöstad Credit Malena Karlsson

Dockside Greens, Credit AquaTex Sci.

Consult.Berlin, Landseberger Tor. Credit Jack Ahern, U.Mass

Water reclamation plant

Courtesy AquaTex, Victoria, BC

Dockside Greens Ecocity, Victoria, BC

Urban streams need base flow Water reclamation plants providing clean effluent for

ecological flow does not have to be far from the city

Base flow can also be provided byo Groundwater inflowso Sump pumps in basementso Upstream streamso Cooling watero Condensate from ACo Stored urban runoff in ponds o Irrigation return flow

None of the above should enter underground sanitary sewers

If water is needed for local reuse, sewers can also be a

sourcePackage and small high efficiency treatment units can be installed to provide locally water for:• Ecological flow of

restored streams• Toilet flushing• Landscape irrigation• Street flushing

Adapted from Asano et al. (2007)

Idea: Concentrate used water for centralized resource recovery

ATERR – Generic anaerobic treatment and energy recovery reactor

PS – primary settler MF microfiltration UV ultraviolet ST storage RO reverse osmosis NF nanofiltration

Double loop (black and gray) separation – Water Machine

Heat recovery

Reclaimed water could be used In applications currently using high quality water

supplies toilet flushing landscape and agricultural irrigation street and car washing pavement cooling to reduce heat island effect

For protecting aquatic ecosystems by providing ecological base flows

For recharging groundwater to enhance available water and/or preventing subsidence of historic buildings built on wood piles;

As cooling waterAs a source of potable water in areas and times of

severe water shortages

Fit for Reuse

Restored stream

Distributed water management and resources recovery

To aquifer

Grey water

Brownwater

Urine

Solid waste

Integrated Resource Recovery Facility = Water/Energy Machine

Surface Water

Ground Water

Rain Water

Energy

Heat E

n.en

ergy Potable

WaterReclaimed non-potable

QualityA,B,C

Hygienized Sludge

Nutrients

Electr

ic En

.

G,R,FX-S Credit Kala Vairavamoorthy

Characteristics of integrated resource recovery facility (IRRF)o More concentrated influent (COD > 1000 mg/L

desirable)o Urine may be separated in clusters (contains 50%

of P and >75% N) in 1% of flow – may be attractive in megalopoli of developing countries – Accra, Ghana)

o Inflow and input contains sludge and other solids (shredded food and other organic solids). Other organic biodegradable solid waste may be trucked in (co-digestion)

Because of high COD, conventional aerobic (energy demanding) activated sludge treatment is not feasible and should be replaced by anaerobic processeso Conventional sludge digester requires large

detention and high concentrations of solids and COD and need a lot of energy

o Use Upflow Anaerobic Sludge Blanket (UASB) reactor

Energy from used water and sludge

Heat recovered by heat pumps

PyrolysisBiogas from anaerobic

processesDigesterUpflow anaerobic sludge

blanket reactorHydrogen fuel cellMicrobial fuel cell

Types of gasBiogas 1Household

waste

Biogas 2Agrifood industry

Natural gas

Composition

60% CH4

33 % CO2

1% N2

0% O2

6% H2O

68% CH4

26 % CO2

1% N2

0% O2

5 % H2O

97.0% CH42.2% CO2

0.4% N2

0.4 % other

Energy content kWh/m3 6.1 7.5 11.3

Energy use in the urban water cycle

Water end consumersCalifornia Germany

kWh/m3 kWh/cap.yr

kWh/m3

kWh/cap.yr

Water Supply, conveyance

0.00-1.06

00-106 0.12-1.13

5-50

Treatment 0.03-4.23

3-423

Distribution 0.18-0.32

18-32 1.26

Heat used by consumer in household for heating water for baths, kitchen, laundry

~11 ~2000 ~21 ~9502

Used water collection and treatment 0.29-

1.2229-122 0.39-

0.8332-75

Total average energy use (without heating)

365

1 Meda et al., Chapter 2 in Lazarova et al (2012) Water Energy Interactions in Water Reuse, IWA Publishing, London2 Energy for water heating per capita/(municipal water consumption)

There is not enough energy in used water

alone ENERGY POTENTIAL - Daily production per capita

COD per capita unit load (including in-sink grinders) 110 gminus COD in the effluent (5%) 105 g

Methane produced 0.4 L/g of COD removed 43 L of CH4

Methane energy 9.2 W-hr/L of CH4 0.4 kW-hr

TOTAL ENERGY POTENTIAL 146 kW-hr/year

TOTAL AVEGAGE ENERGY USE RELATED TO MUNICIPAL WATER USE (WITHOUT HEATING) 365 kW-hr/capita-year

PE

RC

EN

T O

F T

OTA

L M

SW

To: co-digestion,Include also manure, glycols & other biodegradable wastes

To: pyrolysis or recycle

To: recycle

12.4

13.913.4

28.5

8.49.0

4.6 3.4

US EPA : wwwepa.gov/osw/nonhaz/municipal/pubs/msw_2010_rev_factsheet.pdf

Total MSW 225x106 Tons/yr = 2 kg/cap-day

6.4

INTEGRATING SOLID WASTE INTO TOTAL RESOURCE RECOVERY

CODIGESTION Typical biodegradable

solid (food and yard) recoverable waste production in the US is about 0.5 kg/cap-day that can be codigested with the sludge

Codigestates: Food waste, organic deicing fluids, yard waste, oil and hydraulic fluids, meat production waste, yeast, algae produced by CO2 and nutrients from wastewater and many others

Solar and wind energy can be implemented in IRRF and in clusters to provide more energy for heating the reactors and buildings and (in the future) to enhance fermentation and steam methane/carbon monoxide reforming to hydrogen

Waste(PS and/or WAS)

Co-digestates

Biogas

PS-Primary SludgeWAS-Waste Activated Sludge

Credit Dan Zitomer

DRY ORGANIC SOLIDS BIOMASS

Yard vegetation waste Wood Construction lumber waste Agricultural waste solids Dried waste sludge

GR

IND

ING

DR

YIN

G

PY

RO

LYS

ISG

AS

IFIC

AT

ION

R

EA

CT

OR

CH

AR

S

EP

AR

AT

ION

C

YC

LO

NE

BIOCHAR

CO

OL

ING

SYNGASCO + H2

BIO-OIL

TO CLEANING AND

REFORMING

HEAT FOR PYROLYSIS

HEAT FOR DRYING

HE

AT

RE

CO

VE

RY

PYROLYSIS

Examples of new technologies

Microbial fuel cell

Converts organic biomass directly into electricity (from Rabaey and Verstraete, 2005)

Bioelectrochemically Assisted Microbial Reactor (BEAMR)

Converts organic biomass directly into hydrogen by adding small electricity to the reactor (from Liu, Grot and Logan, 2005)

95 % energy recovery from produced acetate

Kim et al. (2011) EST 45:576-581

Upflow Anaerobic Sludge Blanket (UASB) Reactor

BIOGASCH4 + CO2

EFFLUENT

EXCESS SOLIDS TWO STEP

ANAEROBIC FLUIDIZED BED REACTOR WITH MEMBRANE

Contains powdered activated

carbon

BASED ON LETINGA

UASB Reactor• 0.4 L CH4/g

COD removed

• 9.2 kW-hr/m3 of methane

Reverse osmosis

Microfiltration, courtesy Siemens UV radiation

It could be energy demanding

Hydrogen Fuel Cells Convert Biogas to Energy More Efficiently and Cleanly Than Combustion

Installed in Glashusett in Hammarby Sjöstad

O2 from airH2

Water

Steam CO-CH4 Reforming

Heat

CH4, CO2

CO + H2

CO2 S

Electricity

Overall efficiencyHydrogen to electricity 65%With heat recovery 85%

Heat recovery from used water What is the heat or cooling energy equivalent of the energy extracted by the heat pump from a volume V =1 m3 of used water with the temperature differential between incoming and leaving water ΔT = 12 oC. Coefficient of performance of the heat pump varies between 2 – 5. The specific heat of water is Cp = 4.2 J/(g oC). Mass of 1 m3 of water is

ρ=1000 kg/m3 = 106 g/m3. Energy extracted from 1 m3 of water is thenEac = V ρ ΔT Cp = 1[m3] x 106 [g/m3] x 12 [oC] x 4.2 [J/ g oC] = 50.4 x

106 J = 50.4 MJ = 50.4 MJ/(3.6 MJ/kW-hr) = 13.95 kW-hr

If COP = 4 then the energy applied to extract the heat (cooling) from 1 m3 corresponding to the 12 oC temperature change will become

Eap = Eac /COP = 13.95 kW-hr/4 = 3.48 kW-hr.

And the net energy gain is ΔE = Eac - Eap = 13.95 – 3.48 = 10.47 kW-

hr/m3

Picture source James Barnard

Struvite – Ammonium magnesium phosphate

• Adding magnesium hydroxide increases pH and precipitates ammonium and phosphorus as struvite

• pH can be adjusted by sequestering CO2 produced in the treatment process or energy production

Credit Kurita Industries

Upflow fluidized bed reactor

Growing algae fed by nutrients from used water and produced CO2

yields more energy and bio-fuel and sequesters carbon

Biofuel can be used in diesel engines without modifications

Micro-algae offers best prospects

While crops yield 0.5 to 1.5 m3/ha-year, algae can yield 50 to 200m3/ha-year

Algae sequester CO2

Algal Farm – Source ENERGY RANT Source James Barnard, Clark’s lecture

Developing Integrated Resource Recovery Facility - The Water

MachineA. Energy from Concentrated Used

Water recovered by anaerobic treatment

B. Energy from Co-digestion of Sludge and Other High Concentration Liquid Organic Waste and Food Solids

C. Energy from Pyrolysis of Organic Solids (waste wood, wood chips, cardboard, etc.)

D. Heat recovery from effluent and biogas conversion to energy

E. Nutrient recovery

What is Possible 2020 - 2025 ??

2012-2020

DRYING

CH4+CO2

CO+H2

HEATBIOFUELCHAR

MgO

Air

TF

MF UV

PS(Optional)

DIGESTER

UASBR

Pyrolysis

Belt FilterStruvite

Thickener

Condensate

EF

FL

UE

NT

TO

R

EU

SE

CO2

Gas Storage

CO2

Electricity

Engine Generator

METHANE/SYNGAS BASED IRRF

BIOFUEL

Input A

Input B

Input C

Acid to adjust pH

CH4

CO2

2050 or even before ??2038

O2 from air

H2

Water

H2 Fuel cell

HeatSteam

CH4, CO2

CO + H2

CO2

H+

DRYING

S-M-CO-R

HEATBIOFUELCHAR

H2

CO2

MgO

Air

TF

MF UV

PS(Optional)

BEAMRUASBR

Pyrolysis

Belt Filter

UFBR

Struvite

Thickener

Condensate

EF

FL

UE

NT

TO

RE

US

E

HYDROGEN BASED IRRF

CO+H2

CH4

CO2 for pH adjustment and sequestering

Input A

Input B

Input C

H+

HE

AT

EX

TR

EA

CT

ION

H+

H+

SYNGAS

CO2

BEAMR

CH4

UASB-R

DRYING

H2

PYROLYSIS

GAS STORAGEH2 or

CH4

ENERGY FLOW IN IRRF

HEAT

ELECTRICITY

BIOFUEL

BIOGAS

HEAT

PHOTOVOLTAIC

SOLAR HEAT

CHAR

$ FOR EXCESS ENERGY PRODUCTS

$

SMR H2 Cell

HE

AT

PU

MP

EFFLUENT

ELECTRICITY

Dockside Greens, BC (courtesy P. Lucey) Hammarby Sjöstad (courtesy Malena Karlsson)

Masdar (UAE). Courtesy Foster and Associates Qingdao Ecoblocks, courtesy Prof. H. Fraker UC-B

Concepts and technologies are

available and “shovel” ready

ConclusionsUS has one of the highest per capita urban energy

footprintLow density urban centersHigh automobile useGreat reliance on fossil fuel (primarily coal) power

productionAdopting and adapting the ecocity guidelines are

significantly increasing production from renewable carbon free sourcesWater conservation is effectiveBiogas conversion to electricity or hydrogen with carbon

sequestering is effectiveWind turbines on each blockLarge inclusion of solar powerLimiting automobile use, hybrids and electric pug-ins are

very effective Heat recovery from used waterMore efficient appliances and heating (e.g., heat pumps)

The goal of net zero carbon footprint is achievable by 2030 even in the US

Retrofit to the future Begin with satellite water/energy recovery cluster plants

and implement efficiently on-site reuseDevelop resilient and pleasing landscape drainage for

clean water flows Combined sewers will become obsolete and current

sewers oversized. Fit new plastic pipes into sewers and lease the excess space to phone, electricity and cable companies

Implement solar and wind energy in clusters and in private homes – connect to smart energy grid

Focus on development of efficient public transportationConvert existing regional WWTP into IRRF accepting both

concentrated sewage and organic solids and sell the products and energy

The existing capacity is far greater than that needed in the future for the same number of people

http://www.wiley.com/WileyCDA/WileyTitle/productCd-0470476087.htmlhttp://www.AquaNovaLLC.com

Acknowledgment:

Jack Ahern, University of Massachusetts

CDM – Smith (Paul Brown)

CH2M-Hill (Glen Daigger, Masdar team)

IWA COF Steering Committee

Atelier Herbert Dreiseitl

W. Patrick Lucey, AquaTex Scientific Consulting

PUB Singapore + many others