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Winter 2015
NCRWA.COM29
feature
When DCWater hired its energy chief several years ago, the first thing he
did was conduct an energy audit of all the facilities. He then assembled a
list of projects to reduce overall energy use. These ranged from replacing
light fixtures and installing variable control pumps to reduce energy waste
to more innovative long-ranging plans. One of the first major projects he
spearheaded was a $90 million upgrade to the aerobic treatment facility
at the Blue Plains AdvancedWastewater Treatment Plant, which included
installation of fine bubble diffusers in each of the massive treatment
chambers. The new diffusers produce billions of tiny bubbles that rise
from the floor of the aeration chamber to transfer oxygen into the water to
break down waste. “We discovered that it takes much less energy—and
less cost—to push little bubbles than big bubbles,” Hawkins said.
DC Water also built an anaerobic digester system at Blue Plains to
generate renewable electricity for the plant, and is currently considering
covering the plant in solar panels to generate additional power for the
plant and to sell back to the grid. PEPCO has been involved throughout
this process, Hawkins said, noting that the energy services division
designed and built the current power plant and is operating it on a 15-
year renewable contract.
Start Small
While DC Water may be a leader in tracking and managing its water-
energy nexus, it is also one of the biggest water utilities in the country—
with enough resources and expertise on staff to reasonably implement
massive multi-million-dollar projects. But it is the exception. More than
80 percent of water and wastewater utilities across the country have
fewer than 3,300 customers, Warnock said. These organizations don’t
have the expertise or resources on staff to implement energy tracking
and savings programs, and their operators are generally so focused on
day-to-day operations that it can be difficult for them to think about
analyzing energy usage or implementing energy savings programs—
despite the benefits it could bring to their budgets.
But it is possible to have a big impact on energy use with limited
resources. East Bay Municipal Utility District is a good example. The
San Francisco wastewater utility serves 650,000 customers and was
the first wastewater treatment plant in North America to produce more
renewable energy onsite than it needed to run its facility, thanks to the
construction of an anaerobic digester and installation of an energy-
efficient gas. These innovations save EBMUD approximately $3
million per year in power use alone.
And in New Jersey, the Camden County Municipal Utility Authority
covered its sewage treatment facility in 7,200 250-watt photovoltaic
panels that now produce 2.2 million kilowatt-hours of electricity per year,
which has helped the facility significantly lower its electricity usage.
For those utilities that aren’t quite ready to take their operations off the
grid, there are easier and less expensive places to start. An energy audit
is the best first step in identifying energy efficiency opportunities and
to identify low hanging fruit projects, like updating lighting systems
or implementing more efficient energy management processes. These
smaller initiatives require little time or money and can deliver quick
wins that help build support for bigger, more capital-intensive energy
efficiency projects down the line.
One Way to Manage the Water-Energy Nexus
At a time when the electric grid and water systems are both getting
smarter, the opportunity now exists to significantly optimize the water-
energy nexus for those systems.
This requires collecting accurate data about what is happening at
meters and along both electric and water distribution systems, and then
maintaining and using this data to analyze the best way to reduce cost
and energy usage.
“The most effective way to control the water-energy nexus is to gather
the data necessary for good analytics through a single, unified network
that allows collection of water, electric, and gas data into a single head-
end system, where it can be analyzed to identify where the utility is
wasting resources,” said Todd Stocker, director of water and gas
markets for Aclara.
Aclara specializes in smart infrastructure for utilities. The company
recently introduced the Synergize™ RF network, a single system
for reading water, gas and electric meters as well as other devices on
distribution networks.
About the Author: Sarah Fister Gale is a freelance journalist based
in Chicago, Ill. Over the last 15 years, she has researched and
written dozens of articles on water management trends, wastewater
treatment systems and the impact of water scarcity on businesses and
municipalities around the world.
Article Credit: Water World Magazine