Solar-powered autonomous underwater vehicles (SAUVs) may help detect chemical and biological trends. Photo by Sanderson/Blidberg.

As part of RiverNet, Sanderson has worked with a team of researchers to develop the first solar-powered autonomous underwater vehicle (SAUV). The water-monitoring robot will be used to detect chemical and biological trends in various water bodies to guide the management and improvement of water quality. Sanderson is collaborating on the National Science Foundation (NSF)-funded project with the Autonomous Undersea Systems Institute, Technology Systems Inc., and Falmouth Scientific Inc., and LDEO.

There are four fully functioning SAUVs that can network with one another to get a fair assessment of a water body as a whole in measuring how it changes over space and time.

Because SAUVs are powered by solar energy, they can be deployed for long-term projects. Autonomous underwater vehicles (AUVs) equipped with similar sensors are currently used for water monitoring, but must be taken out of the water frequently to recharge the batteries.

Key technologies used to build the 370-pound SAUVs include integrated sensor microsystems, pervasive and distributed computing, wireless communications, and sensor mobility with robotics. The underwater vehicles have captured the attention of the U.S. Navy, which will evaluate their use for coastal surveillance applications.

Last year, Sanderson and his colleagues deployed two of the SAUVs at the DFWI into Lake George to determine communication, interaction, and maneuvering capabilities in testing dissolved oxygen levels, one of the most important indicators of water quality for aquatic life.

“The field tests provided us an excellent opportunity to further our research and technology development of SAUVs. Once fully realized, this technology will allow better monitoring of complex environmental systems, including in the Hudson River,” says Sanderson, who, among his many roles during his 20 years at Rensselaer, has served as vice president of research and ECSE chair.

Following the Flow
Studying the various aspects of contaminants in the Hudson River and surrounding waters in New York and New Jersey has been the lifework of Richard Bopp for nearly three decades.

“A love of chemistry and fishing, much of it on Hudson Basin streams and reservoirs, led naturally to a career in water research,” says Bopp, who was raised in Glendale (Queens, N.Y.).

The Rensselaer geochemist specializes in the analysis of dated sediment cores to determine the sources and distribution of contaminants, such as PCBs (polychlorinated biphenyls), pesticides, dioxins, mercury, and other trace metals. By collecting and analyzing sediment samples, researchers learn about the behavior of pollutants, such as how they persist, how they break down, and how they are transported and deposited in rivers, lakes, and reservoirs.

Bopp’s expertise has been widely used to help develop policy for major contaminant issues relating to the transport and fate of PCBs in the Hudson, the effects of wastewater discharge to New York Harbor, and the impacts of offshore disposal of sewage sludge and dredged material.

As a graduate student at Columbia University in the 1970s, he was the first to trace the downstream transport of PCB-contaminated sediments from the Upper Hudson to New York Harbor.

Suspected carcinogens, PCBs are chlorinated compounds that were used as electrical insulating fluids in capacitors and transformers. Although the manufacturing of PCBs was banned in the U.S. in 1977, the spread of the contaminants throughout the Hudson River and its food chain has created one of the most extensive hazardous waste problems in the nation.

Over the past several years, Bopp has collaborated with EES professor Jun Abrajano to study the sources and history of deposition of another pollutant, called PAHs (polycyclic aromatic hydrocarbons), in sediments from the Hudson and St. Lawrence rivers, and Central Park Lake in New York City. Previously, Abrajano had done pioneering work on PAH sources in Lake Erie and several Arctic lakes.

PAHs are compounds formed during the incomplete burning of coal, oil and gas, and garbage. Toxic to fish and other animals, the chemicals enter water from runoff and through discharges from industrial and wastewater treatment plants.

Using molecular traces and a powerful technique, called compound-specific isotope analysis that he helped develop, Abrajano has found that, overall, PAHs in the Hudson River have generally decreased over the past 50 years.

“The decrease is likely the result of a combination of improved technology, such as catalytic converters and more efficient combustion, that vastly reduced PAH emissions from vehicles as well as tighter regulations on water discharges to the Hudson,” says Abrajano, a biogeochemist.

Abrajano’s isotope analysis technique also measures how effectively pollutants are being degraded by microorganisms and other environmental factors. The technique has been used to provide answers to previously unanswered questions about what happens to pollutants in the environment. For example, his isotopic measurements have been used to distinguish volatilization, biodegradation, and bioaccumulation of PAHs and other contaminants.

Other researchers, such as Marianne Nyman, are using different methods to study water pollution. Nyman, assistant professor of environmental and energy engineering, simulates severe storms in her laboratory to determine the path of hydrophobic contaminants, chemicals that do not easily dissolve in water. Her research could lead to methods to more accurately model and predict the transport and fate of certain pollutants from lake sediment.

		Lake George is one of New York state’s most popular tourist spots, stretching 32 miles long and three miles wide. Photo by Trish Galvin.

“The idea was to compare the two halves to understand firsthand how human development impacts a large water body from the start,” Clesceri says. “If we can understand how that happens, maybe we’d have a better shot at reversing the trend.”

The NSF-funded study included the lake, the shore around it, the area that drained into it, and the atmospheric input, such as rainfall. Multidisciplinary and multi-institutional, it was among the first in the country to combine engineering and ecological disciplines to incorporate a new concept in ecology studies — mathematical modeling of whole landscape systems.

“Today, people understand when you say, ‘We’re going to model an ecosystem.’ But, back then, they would say you can’t model an ecosystem, it’s too diverse. But, in fact, this was the first start to do this in a very big way,” Clesceri says.

To continue his research efforts, Clesceri set up a small laboratory on the lake that would eventually grow into what is now the DFWI. As its first director, Clesceri headed the Institute for 12 years.

Clesceri’s study also provided a foundation for an initiative he established as program director of NSF’s Division of Bioengineering and Environmental Systems, where he served for four years, from 2000 to 2004.

Called CLEANER (Collaborative Large-Scale Engineering Analysis Network for Environmental Research), the initiative provides a central infrastructure for the formulation of engineering and policy options to restore and protect environmental resources, including water sources. It supports collaborations among engineers, natural and social scientists, educators, policy makers, industry, non-governmental organizations, and the public. A main component of CLEANER is a virtual repository of data and information technology that researchers can tap into and share for engineering modeling and analysis.