resource recovery-based sustainable water systems

Date: February 10, 2017

Resource Recovery-based

Sustainable Water Systems

- the City of Tomorrow

Xin (Cissy) Ma

Office of Research and Development

National Risk Management Research Laboratory

New concepts

• Fit for purpose

• Source separation and resource recovery

– Nutrient recovery

– Energy recovery

• Decentralization

1

New concepts

• Fit for purpose



– Energy recovery


2

3

Water Demand and Water Use

Fit for Purpose

• Dual water supply systems

• Non-potable water source “Clean water”

– water reuse from treated greywater and rainwater

Alternative unit processes for non-potable water treatment

• Membrane bioreactors

• Wetland treatment

• Green infrastructure

4

AeMBR and AnMBR Energy Demand Comparison for High Density

Urban Land Use (MJ/Year)

Cashman, S., Mosley, J., Ma, X., Garland, J., Cashdollar, J., Bless D. (2016) Life Cycle Assessment and Cost Analysis of Water and

Wastewater Treatment Options for Sustainability: Influence of Scale on Membrane Bioreactor Systems. EPA 600 R-16 243.

Combined Sewer System vs Green Infrastructure

6

U.S. EPA. Protecting Water Quality from Urban Runoff; http://www.epa.gov/npdes/pubs/nps_urban-facts_final.pdf, 2003.

The role of ecosystem services in urban water systems

New concepts

• Fit for purpose



– Energy recovery


7

Mixed Wastewater vs Source Separation

• There is no such thing as waste, only wasted resources.

• Wastewater composition

8

Urine0

5

10

15

20

25

30

35

40

45

N P K Ca Mg Na Cl S CODtotal

12

13

0.2 0.2

4

7

1

12

1.4 0.7 0.5 0.5 0.2 0.1 0 0.1

41

g/p

.d

Urine

Feces

Stichting Toegepast Onderzoek Waterbeheer (STOWA) (2002). Separate urine collection and treatment:

Options for sustainable wastewater systems and mineral recovery, STOWA.

Urine Separating Toilet

9

Domestic Greywater Production

10

Stichting Toegepast Onderzoek Waterbeheer (STOWA) (2002). Separate urine collection and treatment:

Options for sustainable wastewater systems and mineral recovery, STOWA.

Crisis of Future Fertilizer Supply

• P rock depletion: 50-100 years

11

12

Crisis of Future Fertilizer Supply

• Consume 3-5% of the world’s natural gas production

• 500 million tons of fertilizer per year supporting 40% of the worlds’s population

• Nitrogen fixation - Haber Bosch Process

Fritz Haber1918 Nobel Prize

Professor who

Demonstrated

feasibility

Carl Bosch1931 Nobel Prize

Engineer who

scaled up process

• Smil, V., Enriching the Earth: Fritz Haber, Carl Bosch, and the Transformation of World Food Production The MIT Press Cambridge, MA, 2004.

• Fryzuk, M. D. Nature 427, p 498, 5 Feb 2004

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Urine as a Nutrient Source

• Source separate the flows to maximize recovery

• Struvite crystalization

Mg2+ + NH4+ + PO4

3- = MgNH4PO4·6H2O

Magnesium Ammonium Phosphate

Feces as an Energy Source

• Energy contents in wastewater influent is much greater than energy used at the wastewater plant

• Co-digest with organic waste – increase revenue and reduce landfill

Energy (kWh/m3)

Maximum

potential from

Organic Oxidation

BOD5 54 220 0.85

Organics (COD) 102.6 500

Total solids 54 720

Refractory 180

Particulate 80 0.44

Soluble 100 0.36

Biodegradable 320

Particulate 175 0.56

Soluble 145 0.57

Total 2.78

Wastewater

Constituent

Typical contribution

(g/ca/day)

Typical Concentrations

(mg/L)

Modified from McCarty, P. L., et al. (2011). "Domestic Wastewater Treatment as a Net Energy Producer–Can This be Achieved?"

Environmental Science & Technology 45(17): 7100-7106.

Energy Recovery Technology

• Microbial Fuel Cell

• Anaerobic digestion – Combined heat and power

15

biogas Electricity

Heat

New concepts

• Fit for purpose



– Energy recovery


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Current Urban Water Systems - Cincinnati

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Water Systems for the City of Tomorrow

18 Ma, X., Xue, X., Gonzalez-Mejia, A., Garland, J., and Cashdollar, J. (2015). "Sustainable Water Systems for the City of Tomorrow —

A Conceptual Framework." Sustainability 7(9): 12071

Water Systems for the City of Tomorrow

19 Ma, X., Xue, X., Gonzalez-Mejia, A., Garland, J., and Cashdollar, J. (2015). "Sustainable Water Systems for the City of Tomorrow —

A Conceptual Framework." Sustainability 7(9): 12071

System Analysis Applications: Community-Based Case Study

• Bath, New York

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Bath Project Background & Goals

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• A plant upgrade is required to meet permitted effluent

nutrient standards

• Assess comparative environmental impacts of legacy

and upgraded treatment plants

• Quantify the environmental effect of anaerobic

digestion + composting

• Life cycle cost assessment of upgraded treatment plant

System Diagram

23

Legacy system

24

Upgraded system

Anaerobic Digestion –Feedstock Scenarios

• 3 feedstock scenarios analyzed to determine variation in

environmental and cost performance (300,000 gal tanks)

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Waste TypeBase

(gal/day)Medium (gal/day) High (gal/day)

Primary Sludge 17,654 17,654 17,654

Waste Activated Sludge 75,557 75,557 75,557

Septic Waste 14,000 14,000 14,000

Slaughterhouse Waste - 1,000 4,000

Cheese Waste - 2,000 3,000

Winery Waste - 1,000 1,000

Portable Toilet Waste 2,000 2,000 2,000

Loading (lb VS/1000 ft3/day) 130 158 205

MC3BM3

MC3 So this is different feed size, right?Ma, Cissy, 10/17/2016

BM3 refers to 3 feedstock quantity scenarios.Ben Morelli, 10/26/2016

Anaerobic Digestion Operational

Scenarios

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Parameter Name

Low Yield Base Yield High Yield

UnitsValue Value Value

Percent Volatile Solids Reduction 40 50 60 %

Biogas Yield

Base 12.0 15.0 24.5 ft3/lb VS destroyed

Medium 13.8 18.5 25.1 ft3/lb VS destroyed

High 15.7 22.2 27.3 ft3/lb VS destroyed

Methane Content of Biogas 55 60 65 % w/w

Biogas Heat Content (MJ/ft3) 0.59 0.64 0.68 MJ/ft3

Electrical Efficiency 33 36 40 %

Thermal Efficiency 46 51 56 %

Reactor Heat Loss Northern US Northern US Southern US n.a.

Anaerobic Digestion –Performance Scenarios

MC1BM6

MC1 How about the different levels of emission (compost, etc.)? Since emission is an important parameter influencing GHP.Ma, Cissy, 10/17/2016

BM6 Added a slide (next in presentation)Ben Morelli, 10/26/2016

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Compost EmissionScenarios

Emission Scenario

Emission Species Element

Loss of Incoming Element to GHGs Units

Low CH4 C 0.11% incoming C lost as CH4

Low N2O N 0.34% incoming N lost as N2O

Base CH4 C 0.48% incoming C lost as CH4

Base N2O N 2.68% incoming N lost as N2O

High CH4 C 1.70% incoming C lost as CH4

High N2O N 4.65% incoming N lost as N2O

Eutrophication ImpactsBase Results

• The estimated impact of nutrients (N and P) on waterways

is expected to be reduced by ~46% as a result of the

planned upgrades.

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0.0236

0.0128

-0.005

0.000

0.005

0.010

0.015

0.020

0.025

Legacy Upgraded

kg N eq/m

3wastewater treated

Electricity Natural Gas ChemicalsUnit Process Emissions Effluent Release TransportLandfill Composting Land ApplicationAvoided Products Infrastructure DieselTotal

Eutrophication Impacts -

Scenario Effects

• Eutrophication impacts are relatively insensitive to anaerobic

digestion feedstocks assuming side-stream nutrient removal.

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0%

20%

40%

60%

80%

100%

120%

Pe

rce

nt

of

Leg

acy

Sys

tem

Scenario Names: Feedstock-Anaerobic Digestion Scenario

Global Warming ImpactsBase Results

• Global warming potential increases by ~50% due to

composting, process emissions, and increased electricity

use for the upgraded system.

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0.894 1.35

-0.5

0.0

0.5

1.0

1.5

Legacy Upgraded

kg C

O2

eq

/m3

wa

ste

wa

ter

tre

ate

d

Preliminary/Primary Biological TreatmentFacilities Sludge Handling and TreatmentSludge Disposal Effluent ReleaseTotal

Global Warming –Scenario Effects

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0%

50%

100%

150%

200%

250%

300%

350%

Pe

rce

nt

of

Leg

acy

Sys

tem

Scenario Names: Feedstock-AD ScenarioLow Emissions Base Emissions High EmissionsComposting Scenarios

Cumulative Energy Demand (CED)

Base Results

• CED increases by 22 percent for the upgraded system,

mainly due to electricity use.

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8.71 10.6

-2.0

0.0

2.0

4.0

6.0

8.0

10.0

12.0

Legacy Upgraded

MJ/

m3

wa

ste

wa

ter

tre

ate

d

Preliminary/Primary Biological Treatment

Facilities Sludge Handling and Treatment

Sludge Disposal Effluent Release

Cumulative Energy Demand (CED)

Base Results

• Results displayed by process category

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8.7110.6

-5.0

-3.0

-1.0

1.0

3.0

5.0

7.0

9.0

11.0

13.0

15.0

Legacy UpgradedMJ/m

3wastewater treated

Electricity Natural Gas ChemicalsUnit Process Emissions Effluent Release TransportLandfill Composting Land ApplicationAvoided Products Infrastructure DieselTotal

CED – Scenario Effects

-100%

-50%

0%

50%

100%

150%

Pe

rce

nt

of

Lega

cy S

yste

m

Scenario Names: Feedstock-AD ScenarioLow Emissions Base Emissions High Emissions

Compost Scenarios34

Initial energy burden of nutrient

removal

� Initial energy burden of nutrient removal can be

reduced or reversed by anaerobic digestion.

Cost AnalysisUpgraded System

35

$29

$34

$46

$28

$33

$46

$26

$32

$44

$25

$31

$44

$23

$30

$42

$20

$28

$40

-$10

$0

$10

$20

$30

$40

$50

Low

Cost

Base

Cost

High

Cost

Low

Cost

Base

Cost

High

Cost

Low

Cost

Base

Cost

High

Cost

Low

Cost

Base

Cost

High

Cost

Low

Cost

Base

Cost

High

Cost

Low

Cost

Base

Cost

High

Cost

Mil

lio

n D

oll

ars

Construction ($) Operation ($/yr) Maintenance ($/yr) Material ($/yr) Chemical ($/yr) Energy ($/yr) Total NPV

AD and Compost Payback

• Difficult to achieve with low acceptance of high strength

organic waste.

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Scenario (Feedstock Scenario-Anaerobic Digester Scenario)

Low Cost Scenario Base Cost Scenario High Cost Scenario

Anaerobic Digester

Composting Facility

Anaerobic Digester

Composting Facility

Anaerobic Digester

Composting Facility

Base Feed-Low AD None None None None None None

Base Feed-Base AD None None None None None None

Base Feed-High AD 72 None None None None None

Medium Feed-Low AD None 39 None None None None

Medium Feed-Base AD 271 82 None None None None

Medium Feed-High AD 32 440 177 None None None

High Feed-Low AD 219 11 None None None None

High Feed-Base AD 40 13 251 None None None

High Feed-High AD 16 18 41 None 45 None

Take Home Messages

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• Management of composting and AD facilities are key to maximizing environmental performance.

• Addition of supplemental high strength organic waste benefits the majority of environmental impact categories and cost.

• Environmental benefits of AD are much easier to achieve than unit payback at this small scale.

• Electricity use is a key contributor to environmental impact, indicating the potential benefit of investing in energy efficiency.

Next Steps

• Energy recovery – increase AD size and acceptance of more

high strength organic waste, including their current treatment

processes

• Nutrient management – nutrient removal vs nutrient recovery

• Broader system analysis – environmental impacts (e.g., energy

and nutrient) in the watershed

• Constructed wetland – water reuse

• Revenue analysis – LCC on whether RRH can bring steady

revenue for utility to offset the investment cost

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resource recovery-based sustainable water systems

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