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Current urban systems are mostly linearExcessive water volumes are withdrawn from mostly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