Climate-Friendly Wastewater Solutions

Navigating the Wastewater-Energy-Climate Nexus

Power required for urban water and wastewater management is significant. (Watts per person)

Adapted from Carns, K. (2007) and Daigger, G. D. (2008).

Water Treatment, 4.5

Water Distribution, 8

Wastewater Management, 5

Thermal energy present in wastewater is a potential energy resource that is untapped.

Wastewater is inherently warm: 15.6°C in U.S. (Metcalf & Eddy, 2003)

Heat Exchanger

Cold Tap Water, 6.1°C (Lewisburg, PA, 2/3/09, 6:00pm)

Collection System To hot water heater

75 gal/day at 9°C Δt, 30% efficiency = 18 W/person

Microbial fuel cells tap into the energy wasted in the electron transport chain of microbes.

Limited by hydrolysis of particulate material and efficiency of using the liberated electrons (20%)

O2 CO2

Wasted Energy J.S. Guest ‘05, S. Naha, J. Sole, N.G. Love, I.K. Puri, M.W. Ellis, Virginia Tech,

Photo Courtesy of J. S. Guest

Source separation of urine overcomes some of the obstacles of water reclamation and reuse.

~80% of N, ~ 50% PMajority of pharmaceuticals,

hormones, etc.

(Larsen & Gujer, 1996, Henze and Ledin, 2001)

Nutrient recovery, fertilizer Residential non-potable reuse

Decentralized or on-site treatment

A cautionary tale: We must evaluate consequences of progress.

N2 N2O NO NO2- NO3

-

NH3 NH2OH N2O NO NO2-

300X GWP of CO2

Year

1990 1995 2000 2005

N2O

Em

issi

ons,

mill

ion

met

ric to

ns,

in C

O2

equi

vale

nts

4.0

4.5

5.0

5.5

6.0

Energy Information Administration, U. S. DOE, Report#:DOE/EIA-0573(2005), Emissions of Greenhouse Gases in the United States, 2005

Gilmore, Smets, Terada ,Garland, Lackner, and Love (in preparation).

NH3, 30%

NO2-, 51%

NO3-, 9%

N2O, 10%

Kevin Sullivan, Eagle Eye Inspections, Inc., Washington, Mo., http://www.thisoldhouse.com/toh/photos/ 0,,1614615_1349263,00.html

Image credits:– Wastewater treatment plant – Peppers Ferry Regional Wastewater

Treatment Facility, Radford, VA, photo by K. Gilmore– Power Substation - http://www.sgceng.com/content.php?

sectionID=262&mode=– Sky-scape (public domain)

http://commons.wikimedia.org/wiki/File:Field,_corn,_Liechtenstein,_Mountains,_Alps,_Vaduz,_sky,_clouds,_landscape.jpg

– Microbial Fuel Cell – photo courtesy of J. S. Guest, Univ. of Michigan.– Urine separating toilet – http://www.novaquatis.eawag.ch/index_EN– Plywood septic tank – Kevin Sullivan, Eagle Eye Inspections, Inc.,

Washington, Mo., http://www.thisoldhouse.com/toh/photos/ 0,,1614615_1349263,00.html

Peter Stryker, Associate Professor of Mechanical Engineering—“Energy Consciousness and Conservation”

Tom DiStefano, Associate Professor of Civil and Environmental Engineering—“Renewable Energy from Waste Materials”

Carl Kirby, Associate Professor of Geology—“Geothermal Energy”

Kevin Gilmore, Visiting Assistant Professor of Civil and Environmental Engineering—“Climate-Friendly Wastewater Solutions”

Questions for the panel