Pollution in the Passaic

Investigating the source of invisible but costly contamination in a major NJ river.

Dr. David A. VaccariThat plastic cup floating in the Passaic River is a visible form of pollution, but tiny bacteria in the water could be far more dangerous if found in high enough concentrations, and could cost quite a bit to clean up. The responsibility of determining the source and amount of that pollution falls on Dr. David A. Vaccari, Associate Professor and Director of the Department of Civil, Environmental, and Ocean Engineering at Stevens Institute of Technology. Dr. Vaccari and his team are monitoring key points on the Passaic River for pathogens, in order to determine the sources of these bacteria. “This is big stakes for some people because whoever is responsible will have to take costly measures to fix the problem areas. So a lot of people are paying attention to this,” Dr. Vaccari says.

Dr. Vaccari is Principal Investigator on the project, “Pathogen TMDL Monitoring and FC-EC Relations in the Lower Passaic River. He is aided by co-PI Dr. Richard Hires, Professor Emeritus of Ocean Engineering in the Charles V. Schaefer, Jr. School of Engineering and Science; Dr. Tsan-Liang Su, Research Associate Professor of Environmental Engineering in the Charles V. Schaefer, Jr. School of Engineering and Science; Dr. Sarath Jagupilla, a research engineer at Stevens who graduated the school in 2009 with a degree in Environmental Engineering; and Dr. Robert Miskewitz, Assistant Research Professor at Rutgers University, also a Stevens Ph.D. from 2005.

Modern sewer systems are comprised of two separate sewers: a sanitary sewer that empties in a sewage treatment plant, and a storm sewer that collects from street drains and enters water sources untreated. Sewer systems of the past – the kind found in older communities like Paterson, Hoboken, and New York City, have a single sewer that feeds a sewage treatment plant. Normally this system works fine, but when it rains, the flow is too much for the sewage treatment plant to handle, and the excess flow discharges to the local waterway, a process known as combined sewer overflow (CSO). In the case of Paterson, the sewer discharges into the Passaic River. This leads to undesirable pathogens in the water.

“Federal requirement states that any body of water that does not meet the water body standard designated for that water body should have a governing body determine how much of the pollutant the stream can handle: The Total Maximum Daily Load (TMDL),” Vaccari explains. “We are trying to develop a pathogen TMDL for this stretch of the river to determine the origin of the pathogens as well as how much of the pathogens are coming from the CSOs.”


Vaccari and his team measure levels through the analysis of surrogates that behaves similarly: Escherichia coli, better known as E. coli, and a bacterial group known as fecal coliforms. The levels of these bacteria, which in most forms is harmless to humans, indicates the potential level of the harmful bacteria (i.e. pathogens).

Vaccari and his team are doing a series of six sampling events, four wet weather and two dry, at 16 sampling sites along the Passaic River. The results of the project will reveal where pollution is coming from, so that the sewer system can be analyzed and fixed.

The half-million dollar project is funded by the New Jersey Department of Environmental Protection through a contract with Rutgers NJ EcoComplex via a grant award to Stevens. This includes sampling and testing by Stevens researchers, testing of selected parameters in an outside laboratory, and analysis of data at Stevens.

Environmental Engineering with Dr. Vaccari:
In 2009 Dr. Vaccari published in Scientific American magazine, “Phosphorus: A Looming Crisis,” which addresses and offers a solution for declining levels of this agriculturally significant mineral worldwide, as well as phosphorus-induced algal blooms, which starve fish of oxygen. Dr. Vaccari advocates conservation, suggesting that reducing soil erosion and recycling phosphorus from farm and human waste could help make food production sustainable and prevent algal blooms.

Recently Dr. Vaccari received the Association of Environmental Engineering and Science Professors (AEESP) Award for Outstanding Contribution to Environmental Engineering and Science Education. Learn more on his research profile page.