an effective means of conserving our
limited high-quality freshwater supplies,
while helping to meet the ever-growing
demands for water.” With water rates
rising more than 9 percent annually
across the nation, reducing dependence
on municipal water service is becoming
highly attractive and financially viable in
many parts of the country.
Reducing dependence on
municipal water service is
becoming highly attractive and
financially viable.
On Campus in Chapel Hill
Within the U.S. district energy seg-
ment, the University of North Carolina
at Chapel Hill (UNC) started developing
its comprehensive integrated water rec-
lamation and reuse program seven years
ago. Cooperating with Orange Water and
Sewer Authority (OWASA), UNC brought
reclaimed water to campus for use in
its central utility plant, as irrigation of
athletic fields and for toilet flushing. To
date, UNC has replaced more than 30
percent of its total water use with recy-
cled water, reducing risks and expenses.
In 2011, UNC completed the first
full summer with all chiller plant cooling
towers operating on reclaimed water. Five
of these chillers represent 25 percent of
the university’s total water consumption,
using more than 200 million gal of water
per year. Ray Dubose, director of energy
services, states, “Our use of reclaimed
water, especially with the hot weather,
is setting records. Any reclaimed water
usage reduces the amount of potable
water usage and extends the potable
water available in storage in OWASA’s
reservoirs.”
Prior to final design and construc-
tion of its water reclamation and reuse
distribution system, UNC conducted
more than five years of extensive feasi-
bility studies, including pilot-scale and
microbiological studies to determine
potential impacts. Studies documenting
the performance of the system in reduc-
ing microbiological contaminants and
negligible health risks were done by a
team of students and staff led by Mark
Sobsey, Ph.D., a distinguished professor
of environmental sciences and engineer-
ing. Their published work validates that
reclaimed water can be safely used in
a variety of functions and applications
without substantial risk.
Decentralized Water
Reclamation
As many municipalities have done in
the past, UNC implemented a centralized
water reclamation system, which distributes large volumes of nonpotable water to
bulk users in the community. Although it
benefits the entire community, this model
requires extensive distribution infrastructure construction, long project implementation timelines, substantial capital and
a healthy relationship with the municipal
treatment provider. While UNC has paved
the way with its reclaimed water program
in many respects, it is difficult to apply
this model everywhere.
More often than not, water reclamation is limited by the municipality’s inability to implement a reclaimed water project. In the end, UNC was able to develop
its program because the university has
a close relationship with the municipal
water utility, which contributed substantial funding for the $11 million project.
Today, however, a new approach
exists that makes water reclamation
more accessible to the end user. This
approach, known as decentralized water
reclamation or on-site water reuse, is
considered to be a more financially and
environmentally sustainable approach to
water reclamation and reuse.
Courtesy Organica-Sustainable Water.
The interior of a typical BlueHouse water treatment facility has the look and feel of a botanical garden
enclosed within a greenhouse.
Decentralized water reclamation
or on-site water reuse is a
new, more financially and
environmentally sustainable
approach to water management.
The U.S. Department of Energy is
one of many organizations that has identified the need to look at decentralized
water reclamation, stating that “
heightened concerns about water supply avail-
