Many environmentalists fear the practice of sewage blending would become more routine if a new EPA policy is enacted. (Photo by M. Vasquez)
Officials at the Environmental Protection Agency are considering a new policy for sewage treatment plants. Many environmentalists say if the policy is adopted, it will lead to increased water pollution and greater risk to public health. The Great Lakes Radio Consortium’s Mark Brush reports on the debate over sewage blending:
Transcript
Officials at the Environmental Protection Agency are considering a new policy for sewage treatment plants. Many environmentalists say if the policy is adopted, it will lead to increased water pollution and greater risk to public health. The Great Lakes Radio Consortium’s Mark Brush reports on the debate over sewage blending:
(sound of water in sewer)
Some sanitary sewers are tied in with storm sewers. So when there’s a big rainstorm, or when there’s a fast snowmelt, all that water can inundate some sewage treatment plants. To tackle this problem, some treatment plants have adopted a practice known as “blending.” The excess sewage is re-routed around the slower parts of the treatment plant. The dirty water is then mixed with the water that’s been cleaned. It’s sometimes given a shot of chlorine, and then released into creeks, rivers, and lakes.
Kurt Heise oversees the operation of a sewage treatment plant on the Detroit River. He says the practice of blending is necessary in order to keep the plant from being overwhelmed.
“When you have a wet weather event, an extreme wet weather event, if we were to allow all of that combined water in through the normal process the treatment process would be ruined.”
Sewage blending has been around for a long time. To plant operators, it’s a necessary step in handling large amounts of dirty water. But to some people, blending is not seen as a good option. They want the practice to stop.
Instead, they say, cities should invest in their systems to make sure they can fully treat all the water that comes to the plant. Kurt Heise says, if his plant were required to do this, it wouldn’t make sense economically.
“It would almost result in doubling the size of our plant and spending just untold amounts of dollars for an event only happens a few times a year.”
Sewage treatment plant operators say you have to weigh the costs and the benefits before spending hundreds of millions of dollars on expanding the treatment plants. The decision of whether or not to allow blending has been left up to state and local regulators. But recently, the U.S. Environmental Protection Agency has weighed in on the subject. And ever since they suggested new guidelines for allowing blending, environmentalists have been critical of their plan. Mike Shriberg is the Great Lakes advocate for the Public Interest Research Group. It’s an environmental consumer activist organization.
Shriberg says the draft blending policy, the way it’s written now, is too broad. And will allow the practice of blending to become routine.
“Our fear is that when you’ve got a treatment plant that uses blending, they’re never going to upgrade to full treatment sewage. And so if a treatment plant is allowed to blend they’re not going to go up to full treatment capacity they have no incentive to do that anymore. It’s sort of the cheap way out.”
Sewage treatment operators say blending is better than seeing the raw sewage overflow into waterways. And they say it’s better than spending large sums of money to fix a problem that only occurs a few times a year. But critics say the EPA doesn’t have a good handle on how often blending is used, and what kind of health risks are associated with the practice.
Some initial studies have been done on blended sewage and how it might affect public health. Joan Rose is a water microbiologist at Michigan State University. She’s written a report on the health risks associated with blended sewage.
“So what I found was that if people were actually swimming in the water and there was a discharge of a blended sewage upstream, that their risk of getting sick, actually getting sick with a virus or a parasite was about a hundred times greater – when there was a blended discharge as opposed to if the water was fully treated.”
Rose says some of these viruses, such as Hepatitis-A, are highly contagious. At this point, there are no good estimates on how many people get sick from blended sewage each year. It’s never been studied, so the impact of blending on public health is unclear. Ben Grumbles is the Assistant Administrator for water at the EPA. He says the EPA is considering the billions of dollars at stake in expanding the nation’s sewer treatment plants versus the risk to public health.
“What we’re trying to do is to clarify what’s legal and what isn’t legal and to recognize the economic realities that sewage teatment plants face across the country in terms of their infrastructure needs, but foremost and above all what leaves the facility has to meet Clean Water Act permit limits.”
But the Clean Water Act permit limits don’t measure all the viruses, bacteria, and parasites found in blended sewage. And so some environmentalists and scientists say meeting the limits doesn’t necessarily mean protecting public health. Grumbles says officials are still reviewing the tens of thousands of comments they received after releasing the draft blending policy.
He says he doesn’t know what the final rule will look like, or if they’ll issue a rule at all. One thing is likely, if the policy is finalized the way it’s written now, it’s expected that environmental groups will take the EPA to court.
For the Great Lakes Radio Consortium, I’m Mark Brush.
