After a four-alarm fire at the North River Wastewater Treatment Plant sent gallon after gallon of raw sewage into the Hudson River, some experts suggested Friday that city facilities could use an upgrade. NY1’s Michael Herzenberg filed the following report.

The Hudson River didn't look appealing Friday. In certain areas, it smelled even worse.

About 200 million gallons of raw sewage have been dumped into the river after a fire Wednesday forced the shutdown of the North River Wastewater Treatment Plant.

Greg O'Mullan, an assistant professor at City University working with the nonprofit environmental advocate Riverkeeper, spent Thursday and Friday testing the water around New York City.

“The levels of sewage indicators are many, many times, in some cases hundreds of times, the EPA guidelines,” said O’Mullan.

The assistant professor is worried about the water quality and sewage treatment system.

Columbia University Professor Kartik Chandran has worked with the city on its sewage treatment infrastructure for years and said that it needs improvements.

"The sewage system of New York City is overburdened,” said Chandran. “Very simply, we have way too many people."

He added that some plants are just plain old.

The city's 14 wastewater treatment plants were built from 1903 to 1987. They clean a maximum of 1,805 million gallons of sewage per day.

The North River plant had five hours of storage capacity before the sewage dump into the river became necessary.

Professor Chandran said building more storage isn't practical.

"On one side is the river, and the other side is real estate," said Chandran.

The Department of Environmental Protection has been pumping some of the North River's untreated sewage to another plant, but Caswell Holloway, the DEP commissioner, said that's not a solution, either.

"It’s really a pretty minimal amount,” said Holloway. “That's just a function of the way the city is laid out geographically. It's very difficult to do."

In a news conference Friday, the commissioner said there would be an investigation into what went wrong at the plant and what could be done to the system to save the city from dumping in the river in the future.

Environmental activists are counting on it. Professor Chandran said the city needs more capacity, and the Natural Resources Defense Council wants more plant life to naturally filter out toxins from the water because dumps like this occur every time a significant rain overburdens the system.