Wastewater overflow due to Florence causes health and environmental concerns

When Hurricane Florence hit the East Coast, it moved slowly, dropping trillions of gallons of water on North Carolina causing massive wastewater overflow in towns like Benson.

According to the Town of Benson's Sept. 18 press release, 300,000 gallons of untreated wastewater were discharged into the Neuse River Basin between Sept. 13 and Sept. 18. The discharge was caused by heavy flooding from Hurricane Florence that infiltrated the town’s wastewater system within 72 hours.

The system is permitted to treat a maximum of 1.9 million gallons of water. During the heaviest rainfall, 4 million gallons of water entered the system. 

The discharge also entered the Neuse River Basin, which contains the town of 3,600.

Bridget Munger, a public information officer at the N.C. Department of Environmental Quality, said that the discharge of organic matter into waterways can have harmful impacts, including fish kills and algal bloom. 

Benson was not the only place in the state to experience discharge. Munger said Southside Wastewater Treatment Plant, located just south of Wilmington, discharged 5.25 million gallons of partially treated water. 

While the volume of discharge is alarming, Munger said the dilution factor from the heavy rainfall helped to reduce the damage. 

“You have such a high volume of rainwater and storm surge coming in that will dilute some of these spills, so the immediate impact will not be as severe,” Munger said. “By no structure of the imagination is that saying it’s not a problem to have a spill, but you do have a factor with a huge amount of rainwater that will dilute some of the harmful impact.” 

Munger said the amount of rainwater may help to prevent significant algal bloom that could pose a threat to the environment and to human health. The harmful algae is a type the DEQ specifically advises civilians to avoid.

Munger said the department has identified hog lagoon overflow as a primary cause of the blooms. Hog lagoons are open-air pits filled with animal manure, which, after decomposition, is converted to fertilizer. North Carolina has a large amount of hog lagoons located in the eastern floodplains, which make them prone to overflow during heavy rainfall. 

Gavin Smith, director of the U.S. Department of Homeland Security's Coastal Resilience Center of Excellence at UNC, said the excessive flooding can lead to a whole host of issues if organic matter enters the waterways.

“When excessive rainwater leads to flooding, the waste can overflow,” Smith said. “In some cases, the surrounding levees can be breached, leading large amounts of animal waste flowing into surrounding creeks and rivers.” 

Towns across North Carolina, like Benson, have seen such overflow due to Hurricane Florence's flooding. According to Munger, precautionary measures by the N.C. General Assembly could prevent future spill.

“Whenever we have an emergency event like this in North Carolina, our elected officials are going to be looking back and seeing what changes, perhaps, they need to make to better protect public health and the environment in our state," Munger said.

What new steps the assembly may take following Florence, however, she is not sure.

@HenryHaney17

city@dailytarheel.com