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The Environment Report
Tue January 8, 2013
New Michigan law widens uses for treated sewage product
A new law in Michigan will make it easier for sewage treatment plants to sell or give away their leftovers.
All the water we use in our houses and businesses goes down a municipal drain and ends up in a wastewater treatment plant. It's processed and decontaminated and eventually becomes something called a biosolid.
Some of it then goes into landfills, and some is used as agricultural fertilizer.
A law signed last week will allow Michigan's sewage treatment plant to sell or give away what's called "exceptional quality," or EQ biosolids.
Mike Person with the Michigan Department of Environmental Quality says other states have allowed this for years. In fact, Michigan's been buying a product called Milorganite that's been generated and bagged by the city of Milwaukee.
"It's often used on golf courses and things of that nature. It's pelletized and what it does is provide a nice, slow-release form of organic nitrogen," said Person.
The new Michigan regulations eliminate a layer of bureaucracy. It means these biosolids could be used in public parks, athletic fields, cemeteries, plant nurseries, and on your lawn and garden.
Person says that's an environmentally smart thing to do rather than putting biosolids in landfills or incinerating them.
In order for these biosolids to be given or sold to the public, they have to meet certain criteria.
Dawn Reinhold, an assistant professor in biosystems and agricultural engineering at Michigan State University, says pathogens like E. coli, salmonella and viruses have to be eliminated, and so do harmful metals.
Reinhold says she's researching another aspect of biosolids: What happens to all those personal care products when they get into the water system?
"When you use things like antimicrobial soaps, and you're washing your hands, that antimicrobial chemical is actually going down the drain, ending up in your wastewater treatment plant," said Reinhold. "A lot of that chemical actually ends up on the biosolids."
Reinhold's studies looked what would happen if you were to eat only fruits and vegetables grown in a garden amended with biosolids. She says the health risks would be a thousand to 10,000 times less than from using things like antimicrobial soap in the first place.
But there's one area that still needs work. Reinhold says all those pharmaceuticals Americans use also end up in those treatment plants.
"And so we're starting to understand what is occurring with these chemicals, but as far as being able to completely 100 percent answer that there's no risk from pharmaceuticals in these biosolids, we're not there yet," said Reinhold.
So Reinhold says using biosolids for landscaping limits your exposure to pharmaceuticals to just about nil.
And if you're not comfortable using biosolids in your veggie garden? Go organic.