Getting the Lead out of Newark's Drinking Water
As Newark races to replace thousands of lead-based pipes that feed drinking water into homes, the city faces another urgent challenge: stopping the heavy metal from leaching into the water supply while the massive remediation effort is underway.
And that’s where NJIT’s environmental engineers come in. To mitigate exposure over the life of the project, which is expected to take up to 30 months, a research team is working with the city to develop and test chemical methods to prevent lead-shedding corrosion in as many as 18,000 service lines that stretch from the water main located under streets into dwellings.
“As environmental engineers widely acknowledge, our understanding of the complexities around pipe corrosion and the release of metals continues to evolve. And so must our treatments,” said Taha Marhaba, chairman of NJIT’s Department of Civil and Environmental Engineering and a specialist in analytical techniques for pollution detection. “Our team of faculty and students is developing a more precise, real-time picture of Newark’s water system, in which variable water quality conditions affect the release of lead, and optimizing treatments for this dynamic environment.”
Lead in pipes can become soluble and transportable if oxidized by flowing water, particularly in aging infrastructure that dates back to the middle of the 20th century and earlier in some cities, including Newark. For 25 years, corrosion-prevention in the city’s largest service area, which draws water from reservoirs in the Pequannock River system, consisted of injecting a chemical, silicate, into the water supply. It formed a protective layer of material over the interior surface of the pipe to prevent lead from mobilizing. But testing determined that silicate was no longer effective.
Using X-ray diffraction analysis, the NJIT team assessed the composition of the corrosion in a service line and found that in addition to elemental lead, lead oxides were the compounds most present in the pipe scales. Scanning electron microscopy revealed iron, aluminum, silicon, magnesium and calcium deposits.
“With the introduction of new sources of water, conditions changed. Water quality, including pH, temperature, and organic and inorganic material in runoff, among other factors, plays a big role in the effectiveness of anti-corrosives,” said Lucia Rodriguez-Freire, an assistant professor of environmental engineering who studies the transformation of contaminants and their migration pathways.
With a team of graduate students, Rodriguez-Freire launched a study this past summer of excavated service lines to determine the effectiveness of a new corrosion-control chemical with an affinity for metal surfaces, orthophosphate, which was introduced into the water system last May. While widely used as a corrosion inhibitor in other water systems, where it has successfully stabilized lead, its introduction is not in and of itself an optimal solution, the researchers say.
“Because every water system is different, we have to take other factors into account, such as chemicals in the water, varying seasonal temperatures and weather conditions that can increase runoff,” noted Rodriguez-Freire, “Surface water quality is complex and dynamic. As we continue with our research, we are gaining a better understanding of how seasonal changes, for example, can affect water composition and quality.”
“Ultimately, we will try to pinpoint the best treatment strategies as water conditions change. Specifically, we can study how environmental factors such as pH and temperature affect lead-leaching kinetics under variable doses of orthophosphate in water,” added Wen Zhang, another member of the team, who develops water treatment technologies such as chemically reactive membrane filtration to combat existing and emerging contaminants. The NJIT team is working with the city’s consultant, engineering and construction firm CDM Smith, on the pipe analysis.
The team is setting up a lab on campus to continue testing for the presence of lead in excavated pipes and to determine how well orthophosphate is building up in the service lines to block corrosion, an electrochemical process. Team members, including engineering graduate students Boran Wang (below, seated) and Maedeh Soleimanifar, traveled last fall for training at the EPA’s Office for Research and Development in Cincinnati, which is currently the only lab in the country to perform these tests.
The engineers also will determine whether the chemicals should be injected at different points in the distribution system other than at the water treatment plant. “We need to optimize treatment distribution as well,” Marhaba noted.
Following training and certification by inspection professionals, NJIT undergraduate and graduate students will evaluate pipe replacements to make sure they are being done correctly.
“We have a strong interest and involvement in lead-mitigating programs in our city, Newark,” said Moshe Kam, the Dean of NJIT’s Newark College of Engineering. “At the same time, we use this city-wide effort to educate the next generation of engineers. Graduate and undergraduate students from the College would experience through this project the critical societal impact of engineering; the strong connection between theoretical studies and lab experiments on one hand, and real-life challenges in the urban environment on the other; and the responsibility that engineers owe to the welfare and health of their communities. This experience is likely to serve our engineers-in-training for many years of their future professional careers.”
Lead in drinking water is associated with serious health effects in people, especially children, causing damage to the central and peripheral nervous system, learning disabilities, shorter stature, impaired hearing and impaired formation and function of blood cells, the team noted. The EPA’s goal is to eliminate it from drinking water entirely.
“As an older, urban community, Newark has outdated lead service lines, and we look forward to modernizing our infrastructure and reducing risk for Newark’s families,” Newark Mayor Ras Baraka said this past March, in announcing the city’s pipe replacement program. Locations throughout Newark were prioritized based on the level of risk and the presence of at-risk populations, such as children, while the city is endeavoring to minimize disruption to the existing water system and people living and working in the affected neighborhoods.
NJIT’s civil engineers work on a range of infrastructure projects with the city, from intelligent transportation systems, to dam monitoring and assessment, to water systems.
"We view these efforts as an opportunity for NJIT to contribute to the city’s redevelopment,” Kam added. “By embedding such initiatives that support Newark in our education and research mission, we affirm NJIT’s commitment to improving the environment in our local community."