Climate-Friendly Wastewater Solutions
Navigating the Wastewater-Energy-Climate Nexus
Power required for urban water and wastewater
management is significant. (Watts per person)
Wastewater
Management, 5
Water
Treatment, 4.5
Water
Distribution, 8
Adapted from Carns, K. (2007) and Daigger, G. D. (2008).
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)
Cold Tap Water, 6.1°C
(Lewisburg, PA, 2/3/09, 6:00pm)
Heat Exchanger
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.
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
Limited by hydrolysis of particulate material and efficiency of
using the liberated electrons (20%)
Source separation of urine overcomes some of
the obstacles of water reclamation and reuse.
~80% of N, ~ 50% P
Majority of pharmaceuticals,
hormones, etc.
(Larsen & Gujer, 1996,
Henze and Ledin, 2001)
Nutrient recovery, fertilizer
Decentralized or
on-site treatment
Residential nonpotable reuse
nia
n
on)
rophic
cation
NH3
NO2 -
NH2 OH
A cautionary tale: We Nmust Nevaluate
O
NO consequences
NO
NO
of progress.
-
2
2
2
NO2 -
n
ion)
phic
cation
NH3
rophic
bic
cation
a
NH2 OH
N2
NH3
N2 H4
NH2 OH
N2O
NO
NO2 -
N2O
NO
NO2
-
300XNO
GWP of CO
NO2 2
N2
-
3
NO3 -
NO3
-
NO3
-
b
N 2 O Emissions, million metric tons,
in CO 2 equivalents
n
phic
cation
bic
a
b
n
6.0
NH3
NH2 OH
N2O
NO
NO2 -
NO3-, 9%
5.5
5.0
N2O, 10%
NH3
N2 H4
NH2 OH
N2
NO
NO2
-
NH3, 30%
NO3
-
4.5
NO2-, 51%
4.0
1990
1995
2000
2005
Year
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).
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
Questions for the panel
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”