The clean-water industry decades ago came up with “biosolids” as a term for the digested wastewater solids used for various beneficial purposes.
Sadly, the change has not fully taken hold among members of the public or, perhaps more significantly, among journalists. We still see reporters using terms like “sewage fertilizer” or “sludge fertilizer.”
In an August 31 article about PFAS in biosolids, the New York Times told how “farmers across America have been encouraged by the federal government to spread municipal sewage on millions of acres … as fertilizer.” That characterization (emphasis added) is beyond unfortunate — it borders on slander against the industry.
I found the entire article grossly misleading and highly offensive to clean-water professionals; I strongly suggest you read it (nytimes.com/2024/08/31/climate/pfas-fertilizer-sludge-farm.html?searchResultPosition=4).
About Euphemisms
I tend to think reporters use such terms not to sensationalize, but out of ignorance or, to put it more charitably, misunderstanding. Journalists and, to a lesser extent, the general public are resistant to euphemisms, and to the uninitiated the term “biosolids” seems to qualify.
A euphemism of course is a word designed to make something bad look better. Think “alternative facts” instead of “lies.” Or “enhanced interrogation” instead of “torture.” Or “let go” instead of “fired.”
But “biosolids” is not a euphemism for “sludge” — because the two are not the same. The sludge has been converted through anaerobic digestion and other processes into something very different. This is what journalists and their audiences need to understand, and it falls to clean-water professionals to help them see the distinction.
One simple and effective way I’ve heard for explaining the difference came from a longtime clean-water professional whose name I wish I could recall. He said that in a way, sewage is to biosolids as wood is to ashes. It’s not a perfect analogy, but it conveys the idea that a raw material has been fundamentally changed by a physical process.
How They Say It
That basic idea doesn’t come across clearly in industry definitions of biosolids. The U.S. EPA says, “During wastewater treatment, the liquids are separated from the solids. Those solids are then treated physically and chemically to produce a semisolid, nutrient-rich product known as biosolids. The terms ‘biosolids’ and ‘sewage sludge’ are often used interchangeably.” (The last sentence happens to be true, and that is precisely the communication problem.)
Biosolids management company Synagro says, “Biosolids is the final product created through multiple processes and scientifically advanced treatment of sewage sludge.” (This is rather technical and still includes the ugly term that “biosolids” was supposed to replace.)
The Pennsylvania Department of Environmental Protection says “Biosolids are nutrient-rich organic materials derived from wastewater solids (sewage sludge and residential septage) that have been stabilized, meet specific processing and quality criteria and are suitable for land application. The term, biosolids, comes from the most common method of its production: the biological processing of wastewater solids.” (The last sentence with the italics is creative, but the degree of difference between sewage and biosolids still doesn’t come through explicitly.)
The Australia and New Zealand Biosolids Partnership says, “Sewage sludge is the solids that are collected from the wastewater treatment process but which have not undergone further treatment. Sludge normally contains up to around 3% solids. Sewage sludge is regarded as having become biosolids once it has undergone further treatment to reduce disease-causing pathogens and volatile organic matter significantly, producing a stabilized product suitable for beneficial use.” (This gets at some specific differences, but the repetition of “sewage sludge” clouds the description, which is also rather technical.)
The Washington State Department of Ecology says, “Wastewater from homes and businesses flows to wastewater treatment plants where it undergoes a complex treatment process. Part of the treatment process grows microorganisms that help clean the water. The solid particles that settle out in the first treatment processes continue along for more treatment. The resulting treated solids become ‘biosolids,’ after meeting federal and state standards.” (This is overly technical and still insufficiently clear about the transformation.)
Is There a Better Way?
If all those definitions fall short, then what would a good explanation look like? How about something like this:
“Biosolids are made by converting the solids collected in wastewater treatment into something highly beneficial. Burn wood in a campfire and it turns to ashes, not at all like the original material. In a similar way, treatment turns wastewater solids into a very different product. Odors and harmful microorganisms are largely destroyed, yet valuable nutrients remain. Biosolids have been used safely for decades to fertilize farm crops and landscapes. They are often dried and turned into pellets that can be used even on residential lawns and gardens.”
How about you? Can you suggest a better way to describe biosolids to a news reporter or a resident of your community? I welcome your ideas — send them to me at editor@tpomag.com.
