May 2013, Vol. 5, No.25

Vying for water security

news

Approaches for securing sustainable supply  

Amid intensifying regional droughts, higher population forecasts, and rising concerns associated with climate change and dry future conditions, governments and municipalities are hurrying to establish long-term water security for growing communities and populations. They are locking in water rights, initiating sustainable water-saving solutions, and building alternative water supply projects that make use of available sources. Additionally, market-based strategies and incentive mechanisms for protecting water resources offer additional tools for preserving water quality and managing water supplies. 

Watershed investment approaches  

Globally, the number of programs that involve investments in
watershed services —including payments for ecosystem services, water funds,
reciprocal agreements for water, and benefit-sharing arrangements — has
steadily increased since tracking began in 2008, according to a recent report
by Ecosystem Marketplace, an online source for news, data, and analytics on
markets and payments for ecosystem services. The 2012 State
of Watershed Payments
report found 205 active programs around the
world valued at $8.17 billion that include these types of projects and schemes.

The uptrend in water market investments has continued to
expand and attract more attention as a key strategy for water security despite
the economic downturn, said Jan Cassin, water initiative director at Forest
Trends (Washington D.C.), an international nonprofit organization that oversees
Ecosystem Marketplace. “We are seeing a global movement in implementing these
types of payment structures for watershed services, which can include efforts
toward maintaining supply, improving water quality, and protecting against
flooding,” she said.

The mechanisms for
investments for watershed services can be broad, including bilateral payments
from users to suppliers or actual water markets where rights are purchased to
keep water in streams, according to Cassin. “Other methods don’t involve cash
transactions but are really more reciprocal agreements between upstream and
downstream communities,” she said. “A common example would include an urban
downstream community providing technical assistance, training, or even
materials to a rural upstream community for helping them better manage the land
for improving water quality.”

Compared to the past, when most strategies for water security
included technological or traditional engineering methods, the mechanisms today
increasingly involve more natural-ecosystem approaches, Cassin said. “Natural
infrastructure solutions are frequently more cost-effective and provide
additional benefits beyond the pure water security target,” she said.

The report notes that in the U.S., there exists strong
interest and growing adoption in source water protection strategies, including
drinking water protection initiatives and government-led programs to protect
watersheds.

"The cities of Denver and
Santa Fe [N.M.] are working with the U.S. Forest Service and private landowners as part of programs that invest in
watershed management as a strategy for ensuring long-term supplies of clean
water,” Cassin said. “Both cities are taking approaches toward protecting their
watersheds by ensuring that the forests are managed in a way for improving forest health to decrease potential damage that could
occur to water supplies from wildfires and the resulting increase in sediment
entering streams and reservoirs.” 


Pursuing groundwater rights  

In water-stressed central
Texas, long-term water security is being viewed with increasingly heightened
importance, especially considering the severity of recent droughts that have
plagued the state. This, combined with expected significant growth, is
prompting several cities and agencies in the region to pursue water rights that
are needed for serving fast-growing communities. But with surface waters
dwindling and the rights to those supplies mostly taken, groundwater has
emerged as a preferred option for supplying future needs.

One entity targeting groundwater as a future supply source
includes the Hays Caldwell Public Utility Agency (HCPUA) in San Marcos, Texas.
HCPUA was formed for the purpose of resolving the long-term water needs of the
cities of Kyle, San Marcos, and Buda, Texas, as well as the Canyon Regional
Water Authority. HCPUA recently secured permits for transporting up to 12.7
million m3 (10,300 ac-ft) of water per year from the Carrizo–Wilcox
aquifer in Caldwell County, located approximately 64 km (40 mi) east of
Interstate 35.

"Since immediate groundwater systems were already permitted,
HCPUA had to go searching for outside sources that could be used for providing
long-term supply,” said Graham Moore, HCPUA acting general manager. “The
prospect of drought is a significant concern, but the real driver behind this
effort is to find a water supply that supports the explosive growth that is
occurring on the I-35 corridor between San Antonio and Austin [Texas].”

In leasing land in Caldwell County for the rights to
underground supplies, HCPUA encountered several obstacles. “We had to find a
financial incentive for landowners who were hesitant to agree,” Moore said.
“Additionally, the land we leased had to be contiguous, which posed its own
unique set of challenges.”

With multiple public and private entities vying for aquifer
rights and other restrictions limiting the amount of water available, the
environment in central Texas has become very competitive for securing permits
to long-term groundwater supplies, according to Moore. In the Gonzalez County
Underground Water Conservation District, where HCPUA is now permitted, a total
of five different public and private groups now have secured aquifer rights,
with all anticipated to export groundwater out of the county. “This scenario is
being replicated in other areas of the Carrizo–Wilcox aquifer,” Moore said.

 

A multipronged strategy  

In nearby San Antonio, the
solution for achieving long-term water security involves a mix of different
innovative, technological, and water-conserving approaches. In contrast to
other agencies in Texas competing for coveted supplies, a large component to
the strategy set forth by the San Antonio Water System (SAWS) was to
intentionally go after water that nobody else wanted.

This reasoning is what led to the $154 million
reverse-osmosis brackish groundwater desalination project, currently being
built by SAWS. The first phase of the project, scheduled for completion in
2016, will produce roughly 38,000 m3/d (10 mgd).

“Most of the competition for water sources is focused on
freshwater supplies located in shallower aquifers,” said Kelley Neumann, senior
vice president of strategic resources at SAWS. “We decided to drill deeper and
access the brackish water located in a deep aquifer positioned below another
aquifer that nobody else was using. The water that we found is not too brackish
as to be problematic to treat.”

As another adaptive
strategy, SAWS uses aquifer storage and recovery, a scheme set in response to
pumping restrictions from the Edwards Aquifer, the city’s primary freshwater
supply. “During drought cycles, we can lose approximately 40% of our rights to
this source,” Neumann said. “However, the Edwards Aquifer is an artesian system
that can recharge very rapidly. When the water table is high enough, we take
water from this aquifer and pump it south 17 miles [27 km], where it is
injected into the Carrizo Aquifer, which has very little movement and is
adequate for storage.”

SAWS maintains approximately 111 million m3
(90,000 ac-ft) of stored water in the Carrizo Aquifer — nearly a third the
amount of water used by the city in a year — which can be used for
supplementing the city’s potable water system during routine drought periods.

As another strategy for water security, SAWS treats effluent
for nonpotable water reuse in the city. High-quality recycled water is used for
landscape watering, golf course irrigation, and in cooling towers for local
industries. Additionally, a local Toyota plant uses the recycled water in its
manufacturing process. “We initiated the recycled-water system because it
represents water we wouldn’t have to fight over,” Neumann said.

Demand management, another significant element of SAWS’
long-term water security plan, involves a programmatic effort toward water
conservation, greater water efficiency, and the use of drought-tolerant plants
and grasses.

Jeff Gunderson, WE&T 


 

Heating up college life

A Nebraska college campus will use wastewater to heat its buildings in a more cost-effective, environmentally friendly way

Using heat recovered from treated wastewater to warm
one or multiple facilities isn’t a new development. Several innovative
municipalities and utilities have employed this technique. For example, in
December 2010, the town of Avon, Colo., in coordination with the Eagle River
Water and Sanitation District (Vail, Colo.), completed installation of a
heat-recovery system fueled by heat drawn from wastewater effluent before the
effluent is discharged to the nearby Eagle River. The system provides heat to a
few town- and district-owned buildings and all the swimming pools at the local
community center. But sometime next year, the University of Nebraska—Lincoln
may become one of the first U.S. college campuses to use this technique to help
supply heat to its conference office, labs, and greenhouse space. The new
heating system is being built on the university’s 195,000-m2
(2.1-million-ft2) Innovation Campus.

“This system, as opposed to a traditional
heating/cooling system, is a little cheaper,” said Dan Duncan, executive
director of Innovation Campus. “A lot of it is that you aren’t using building
space for boilers and chillers.”

Duncan said the university came up with the idea to
use this type of heating system, rather than a boiler/chiller system, on its
new public–private research campus because the campus is on the old state
fairgrounds, which is adjacent to a Lincoln water resource recovery facility
that processes 57,000 L/min (15,000 gal/min) of 16°C (60°F) water.

The university plans to run the wastewater through heat exchangers and
build the system with redundancy so that if one pipe fails, the entire system
doesn’t shut down, Duncan said. Before starting the project, the engineers
consulted U.S. Air Force engineers who had built similar heat-recovery systems
using wastewater.

So far, the biggest obstacle with the Innovation Campus project is
making the option realistically affordable by securing adequate funding. Duncan
said that engineering specs showed the university could heat 140,000 m2
(1.5 million ft2) with the heat-recovery system.

“We wanted to provide energy at the same Btu rate that people of
Nebraska would pay for other energy costs,” Duncan said, but they discovered
that 56,000 m2 (600,000 ft2) was the break-even point. To
offset the costs, the university is working with a private developer who found
qualified energy conservation bonds to help with funding, he said.

According to the Database of State Incentives for
Renewables and Efficiency website, the type of projects that can qualify for
these bonds is “fairly broad and contains elements relating to energy
efficiency capital expenditures in public buildings that reduce energy
consumption by at least 20%; green community programs (including loans and
grants to implement such programs); renewable energy production; various
research and development applications; mass commuting facilities that reduce
energy consumption; several types of energy-related demonstration projects; and
public energy efficiency education campaigns.”

No one in Nebraska had used these credits/bonds that
were made available through federal legislation, Duncan explained. So, the
Nebraska governor agreed to move $15.6 million of bonding authority to the City
of Lincoln, which would issue the bonds. The campus developer would then buy
the bonds. By doing this, the university could bring in an additional 33,000 m2
(350,000 ft2) to the heating system, and the energy rates would
still be affordable.

The first building on campus will be on-line in or before Jan. 1, Duncan
said. Most of the construction is starting this spring.

“We are feverishly engineering and designing. … The piping needs to go
in at the same time as the utilities before the roads can go in,” Duncan said.

— LaShell Stratton-Childers, WE&T 


 


Treatment system cleans acid mine drainage with minimal cost, effort in South
America

U.S.-based researchers are
in Bolivia testing a passive treatment system as an inexpensive way to treat
acid mine drainage in a poor, arid country that depends on local water for crop
irrigation.

The project, conducted by a team from the University of
Oklahoma (OU; Norman) Center for Restoration of Ecosystems and Watersheds
(CREW), began 6 years ago in the city of Potosi in the rural highlands of
Bolivia, according to Robert Nairn, CREW director.

The passive treatment
system captures contaminated water from the mines and consists of several
clay-lined ponds in which different constituents are removed or settled out.

One mountain alone in the region annually discharges through
its water an estimated 146 Mg (161 ton) of zinc, 142 Mg (157 ton) of iron, and
more than 1.8 Mg (2 ton) of arsenic, in addition to dozens of other toxic
minerals, including cadmium and lead, according to the OU Water Technologies
for Emerging Regions Center.

 

Passive system requires little oversight 

Treated water travels through the system by gravity,
requiring little electricity. And because the system is powered by the sun,
wind, and gravity, it requires minimal labor and only has to be checked about
once every 3 months, Nairn said.

The amount of water treated varies, Nairn said. “Given the
variable seasonal nature of water flows in this climate, ‘capacity’ is a tough
question,” he said. “It varies greatly from zero to hundreds of gallons
per minute.”

Two oxic limestone drains treat acidic water draining from
two historically polluted lakes, according to Nairn. An anoxic limestone drain
essentially consists of a previously open mine portal filled with limestone and
is plumbed to retain water at a given elevation. The anoxic limestone
drain discharges into an oxidation pond for metal oxidation, hydrolysis, and
settling.

Effluents from both oxic limestone drains and the anoxic
limestone drain and oxidation pond flow into Laguna Santa Catalina, an
irrigation water source in the nearby agricultural valley.

Nairn said his team recently finished Phase 1 of the Bolivia
treatment system, during which the team built the system to capture acid mine
drainage from abandoned mines. In Phase 2, which is about to begin, Nairn said his
team will work with the Bolivian government and mining company owner to look at
a “suite of ideas” for addressing mine-portal discharge and tailings-pile
leachate sources.

 

Initial results promising 

So far, Nairn said his team has preliminary data on pH and
alkalinity. The pH levels increased from 3 in influent to 6.5 in the final
pond, and alkalinity increased from zero to 100 mg/L calcium carbonate
equivalent.

“Our data set for the Bolivian system is quite limited, as we
rely on our partners for data collection,” Nairn said. The work in Bolivia is
conducted in concert with multiple partners, including Saint Francis University
(Loreto, Pa.), Rotary International (Evanston, Ill.), Engineers in Action
(Tulsa, Okla.), and Universidad Autonoma Tomas Frias (Potosi, Bolivia), among
others.

“We need more data, and
we’re working on convincing the Bolivian government that monitoring is
important” in Phase 2, Nairn said.

Similar passive systems have shown decreases in all
constituents. The Bolivian system is similar to one used at the Tar Creek
Superfund site in Oklahoma, part of the historic Tri-State Mining District of
Oklahoma, Kansas, and Missouri. Nairn and his team designed the Tar Creek
system to treat abandoned ferruginous mine waters.

“There are actually probably several hundred passive
treatment systems in the U.S.,” Nairn said. “We are by no means the only
research team examining these technologies.”

Final effluent waters at Tar
Creek had a pH greater than 7 and contained less than 1 mg/L total iron and
less than 0.1 mg/L total zinc, with concentrations of cadmium, lead, and
arsenic below detectable limits. Significant quantities of lead and zinc were
produced from the Tri-State Mining District
from the 1890s through the 1960s.

Nairn said his team is using the passive treatment system to
understand the magnitude, extent, and rates of multiple processes in order to
optimize performance and provide ancillary benefits.

“We’re ‘opening the black box’ in these systems by examining
specific microbiological and biogeochemical mechanisms,” Nairn said. “Depending
on the unit process, we are focusing on geochemical dissolution, metal
oxidation, metal hydrolysis, sorption, precipitation, sedimentation,
coprecipitation, vegetative uptake, fermentation, bacterial sulfate reduction,
and oxygenation.”

 

Construction costs kept low  

The passive treatment system in Bolivia, which cost $75,000
to build, was funded by a Rotary International grant, Nairn said. This cost
covered only the materials and their transportation; construction was completed
by volunteers from various international student groups and local
organizations, Nairn said.

In comparison, the Tar Creek Superfund site system cost $1.2
million for a 10-cell parallel treatment train, Nairn said. Other sites in the
U.S. that use the system cost about $100,000 to $250,000 to design.

“Each design is site-specific, so we have a significant range
of costs to build a passive treatment system,” Nairn explained.

The primary differences
between the Tar Creek and the Potosi projects are the extreme geographical
conditions, Nairn said. Instead of Oklahoma flatlands, the team is working in a
desert at elevations of 4900 m (16,000 ft), which poses numerous challenges.

“We have attempted to transfer these technologies to [a] mountainous,
high-desert region where water is an even more precious resource and where poor
quality water used for irrigation has direct human health impacts,” Nairn said.

Nairn said his work brought him to Bolivia for those reasons.
“Bolivia is one of the poorest countries in the Western Hemisphere and has a
long and storied mining history, so it provided a good match for my interests,”
he said.

— Cathy Chang, WE&T 


 

 

More utilities embracing public–private partnerships

Innovative arrangements can help utilities reduce risks and leverage expertise from the private sector

Last year, the U.S.
Environmental Protection Agency (EPA) released a study detailing that $330
billion is needed during the next 2 decades to fund critical water and sewer
upgrades across the U.S. But despite the significant and increasing need,
constrained federal and municipal budgets continue to limit funding
opportunities for projects. This dilemma is pushing an increasing number of
utilities toward public–private partnerships, which can provide immediate
upfront capital and a longer-term financing mechanism for getting projects off
the ground and built.

Chris Crockett, deputy commissioner of planning and
environmental services at the Philadelphia Water Department (PWD), said the
water and wastewater industry is currently in a “perfect storm” of aging
infrastructure, greater regulatory requirements, and shrinking or flat-lining
revenues. “Since the public is not open to rate increases, utilities are forced
to become more innovative in their financing approaches,” he said. “This is
triggering a growing trend among utilities toward [public–private partnership]
structures as a means for achieving their capital needs.”

More than 30 states have passed legislation that paves the
way for future arrangements, including design–build, design-–build–operate, and
design–build–operate–finance, as well as operations, maintenance, and
management partnerships.

By benefiting from the efficiencies of the private sector,
these partnerships can enable utilities to deliver their capital programs in a
more cost-effective way, according to Crockett. “Private enterprises can share
resources and spread costs over many clients, allowing for a higher degree of
optimization as compared to the municipal model, which requires dedicated
investments,” he said.

Municipalities also can benefit from the technological
expertise that is available from the private sector, said Michael Deane,
executive director of the National Association of Water Companies (Washington
D.C.).

“Instead of procuring the skills in-house, it can make more
sense for utilities to reach out to a private partner that specializes in
designing, building, and operating a particularly difficult part of a new
system, whether it involves biogas generation, sludge management, or advanced
water treatment,” Deane said. “The private sector is more aligned for
risk-taking, which, in effect, drives innovation and expertise.”

Although utilities traditionally have tended to resist these
arrangements because of concerns associated with privatization of assets and
potentially losing control of critical infrastructure and facilities, Crockett
said today’s partnerships can be structured in many ways so that communities
retain ownership.

An example is PWD’s arrangement with Ameresco (Framingham,
Mass.) to design, build, and maintain a new $47.5 million biogas project that
will generate enough electricity and thermal energy to supply 15% of PWD’s
annual energy usage over a 16-year contract.

“We have a shared maintenance agreement … that will allow
staff to operate the facility, but maintenance of specialized equipment will be
initially conducted by our private partner,” Crockett said.

Crockett said that in structuring these arrangements,
utilities should develop an effective political strategy and strong business
teams that can identify risks and mitigate them through the deal. “[These] are
complex arrangements that take utilities outside of their normal procedure and
controls,” he said. “From our experience in developing the biogas facility
agreement, the biggest challenge was in regards to the legal, political, and
administrative hurdles. It took a significant amount of effort from broad
resources in the organization to complete it in time.”

 

Risk transfer 

Another major driver for
public–private partnerships is the ability of municipalities to transfer risks
associated with new, capital-intensive projects. Such is the case with the
large, recently approved $1 billion seawater desalination project in Carlsbad,
Calif., which is expected to produce up to 189,000 m3/d (50 mgd) of
water by 2016. The project is a design–build–operate–finance contract between
the San Diego County Water Authority and developer Poseidon Resources Corp.
(Stamford, Conn.) in which the water authority will act as the sole purchaser
of water, buying up to 69 million m3 (56,000 ac-ft) of water
annually.

“The project is
technology-dependent, and as an agency, we have no experience with
desalination,” said Ken Weinberg, director of water resources at the San Diego
County Water Authority. “With this arrangement, we are insulated from the
technological, development, and operating risks associated with an undertaking
of this level.”

The project will be financed through private equity and
private activity bonds, as well as governmental purpose bonds for financing a
16-km (10-mi) water delivery pipeline that will travel from the plant to the
water authority’s aqueduct. Under the agreement, the water authority will pay
only for water, and at a price that can only be adjusted for inflation and
certain predefined circumstances.

"We are paying a slightly higher rate for financing than if
we built the project ourselves, but [we] will not have to shoulder the burden
of handling the engineering and construction procurement delivery or the risk related to the technology not working as
advertised,” Weinberg said. “Altogether, that was more risk than we were
willing to accept. It came down to balancing the price for desalination water
with the affordability of our water rates, and optimizing the risk–cost
equation.”

 

A sustainable approach 

Public–private partnerships also are being used for long-term
water and wastewater services management. In Rialto, Calif., a public–private
concession agreement was recently formed between Rialto Water Services and
Veolia Water North America (Chicago) for the purposes of strengthening the
city’s financial position and improving infrastructure services during the next
30 years. The contract would provide approximately $300 million in revenues for
Veolia.

“The City of Rialto
has been faced with the need to invest in its aging water and wastewater
infrastructure, but because of a difficult financial environment has been
unable to pursue a program for improving its facilities,” said Shilen Patel,
director of business development at Veolia Water. “This partnership allows the
city to leverage the needed expertise for upgrading its systems and improving
the efficiency and reliability of its water and wastewater services, ensuring
future economic growth.”

The financing model includes $35 million in upfront capital
and $41 million in funding for future water and wastewater improvements. Under
the terms of the concession agreement, Veolia Water will assume operational
responsibility of the water and wastewater systems, but the city will retain
public ownership, control, and authority over rate-setting.

Jeff Gunderson, WE&T 

 

©2013 Water Environment Federation. All rights reserved.