By Ashley Soebroto
Boston University Statehouse Program
BOSTON — As sewage overflows become more frequent in Massachusetts, advocates and lawmakers are pushing to reduce the number of combined sewer systems to avoid run-off sewage polluting bodies of water.
Legislation on Beacon Hill would require the Massachusetts Water Resources Authority — which provides water and sewer services to 60 Greater Boston communities — to adopt regulations that aim to reduce the impact of combined sewer overflows, or CSOs, on public waterways.
“Pretty much every time it rains, combined sewer overflows do occur,” said Katharine Lange, policy director at the Massachusetts River Alliance, in an interview. “It doesn’t have to be a big standout event — if you’re out and there’s a smell, it’s sewage pollution.”
Some Massachusetts communities have combined sewer systems — those that transport sewage and urban run-off together to a sewage treatment plant or disposal site. And depending how much it rains, this can cause those systems to reach their full capacity, or even overflow.
To prevent sewage backups into homes and streets, relief points are built into wastewater systems to discharge the sewage-rain mixture into the nearest body of water.
Lange said dumping sewage into bodies of water is permitted by state law in cases where sewage systems become overwhelmed.
“It’s important to note that this is not an error,” she said. “These systems were designed to discharge like this so that you avoid backing up people’s homes and overwhelming treatment plans. But as a result, we’ve designed ourselves a new pollution problem.”
A bill on Beacon Hill would require the MRWA to no longer have combined sewage overflows (CSOs) by 2035 caused by “25-year, 24-hour storm event or smaller storm event.” In other words, “for all our regular everyday rains, CSOs shouldn’t be happening,” according to Lange.
Combined sewer overflows and climate change
Most modern systems carry rainwater and sewage from homes and businesses separately. But older combined systems carry both together, reducing the sewer system’s capacity. Intense rain can overwhelm those systems, resulting in an overflow.
According to a Dartmouth College report in May, researchers predict the Northeast will see 52% more storms that drop at least 1.5 inches of rain by the end of the century. These incidents can have negative impacts on water quality, aquatic life and public health for those who use rivers and other bodies of water for recreational activities.
“As you can imagine, contamination leads to eye and skin irritations, and E. coli,” Lange said. “There’s even evidence in the pandemic that it could spread COVID.”
She added that CSOs occur more frequently in urban environmental justice areas with low-income and historically marginalized populations.
Sanitary sewer overflows
While most MetroWest communities do not have combined sewer systems, there’s a similar issue that bodies of water in the area face: sanitary sewer overflows, or SSOs.
Alison Field-Juma, executive director of OARS Inc. — which advocates for the Assabet, Sudbury and Concord Rivers — explained that SSOs are discharges of sewage into waterways.
Like the MWRA, municipal treatment plants have received permits from the Environmental Protection Agency and the state’s Department of Environmental Protection to discharge sewage into waterways, albeit at low concentrations.
However, Field-Juma said waterways such as the Assabet River contain various pollutants from wastewater, despite the discharge having been treated and cleaned.
“A lot of the flow of the Assabet River is actually flow from the wastewater treatment plants because wastewater is produced all the time,” she said. “Doesn’t matter whether it’s winter or summer, there’s always flow coming out of those plants.”
While it can have major negative repercussions for the environment and public health, Field-Juma pointed to another area of concern: nutrition pollution.
According to the National Oceanic and Atmospheric Association, bodies of water can be polluted by excess nutrients, such as nitrogen or phosphorus, which stimulate algae growth. The algae can block light needed for plants and cause low oxygen levels in the water, harming aquatic animals.
Solutions for CSOs and SSOs
Lange said one solution is adding green infrastructure projects such as parks, street trees, green roofs and permeable pavement. These structures would absorb stormwater when it lands on the ground to reduce the amount that enters combined sewer systems.
Field-Juma said upper level municipalities should continue to invest in wastewater treatment plant technologies, as well as ensure that filtered wastewater is discharged into the ground instead of being dumped straight into bodies of water.
“What we want is for that wastewater to be treated and discharged into the ground,” Field-Juma said. “When it’s treated and discharged into the ground, it then can still get filtered and slowly make its way over to water bodies in a much more healthy way.”
Field-Juma added that municipalities need to have stringent wastewater discharge permits and standards for sewage treatment plants. And Lange said advocates can comment on permits that sewer operators receive to legally discharge sewage into waterways.
“Those permits are renewed sometime and come up for comment,” Lange said. “There is an opportunity to comment through the permit process to say, ‘Hey, you guys should really reduce your sewage discharge.’”
She added that sewage overflows are not a new issue, but as climate change worsens and exacerbates this problem, sewage operators need to start planning and taking action.
“These (sewage systems) were built a century ago and at that time, we weren’t thinking about climate change,” Lange said. “What we’re experiencing now is far beyond what was envisioned these systems could handle, and that’s only going to change and get more extreme as climate change progresses.”
This story originally appeared in the MetroWest Daily News.