The saying "one man's trash is another's treasure" may not better fit a situation than the biosolids recycling process, which is used to convert broken down sewage sludge into a useful type of fertilizer. However, the public, as well as state and federal regulators overseeing the process, should be mindful that despite advances in modern science, there still is no philosopher's stone remedy for converting garbage into gold.
Referred to as biosolids, and commonly marketed as "organic fertilizer" under branded names like Milorganite, which has been available to the general public for decades, biosolids fertilizers are made from sludge formed during the wastewater treatment process. In other words, human waste and all the other sewage taken out of water at wastewater treatment plants.
While the ability to recycle those sludges has been known for many years, the practice of applying treated biosolids to thousands of acres of farmland in Michigan is a more recent trend. And, although there is value to farmers and wastewater treatment plants in recycling biosolids, we believe additional research and controls are needed at the state and federal level before turning a blind eye to the potential dangers such material poses to human health and the environment.
In Michigan, about 85,000 tons of biosolids fertilizer is applied to some 18,000 acres of farmland, with about 32,000 tons of that used for growing crops for human food consumption. Most, if not all, of the biosolids used on crops for human consumption comes from the Great Lakes Water Authority's (formerly the Detroit Water and Sewerage Department) wastewater treatment facility on Jefferson Avenue in Detroit. The remaining biosolids generated in Michigan aren't considered safe enough to be used for growing crops that people will eat.
While federal law restricts lower grade biosolids from being used for people, the Michigan Department of Environmental Quality's Biosolids Program, which is responsible for enforcing the federal regulations, has just five full-time employees working to monitor biosolids applicators. A 2003 audit of the program found operational deficiencies in it. Further, the case in the early 2000s of potentially tainted pickles that were grown with biosolids unapproved for such uses – discovered by the DEQ only after being alerted by a neighbor – illustrates that additional resources are needed to ensure regulations are being followed.
Contaminants that may be found in biosolids range from cancer-causing PCBs, and PAHs, heavy metals, pharmaceutical products and other chemicals. Regulations provide that measures are taken to destroy disease-causing pathogens, as well as about a dozen other contaminants. However, the Environmental Protection Agency (EPA), by its own admission, has said it is in the process of evaluating more than 135 potential contaminants in biosolids.
The impact on human health of eating food grown in biosolids, whether within federal regulations or not, is relatively unknown. While some research has been done on the matter, there seems to be no conclusive findings on the longterm impact of foods grown with biosolids.
Because of the degree of uncertainty, we believe consumers should have the ability to know whether food they are purchasing was produced with the use of biosolids. However, that ability is mostly non-existent, outside of foods labeled as "certified organic," which prohibits the use of biosolids in their production.
At least one retailer, Whole Foods, has taken efforts to provide their customers with additional knowledge about produce with its "Responsibly Grown" rating system that prohibits the use of biosolids on land within three years prior to harvest. We feel it is imperative for all foods grown using biosolids to include additional label information, similar to labeling for genetically modified foods (GMOs).
Lastly, we believe additional oversight may be needed to protect the environment where biosolids are applied. Fertilizers, in general, have been fingered as a contributor to toxic algae blooms in Lake Erie, as well as a potential contaminant to groundwater. Additional steps are warranted to ensure biosolids applied to fields remain on those fields, rather than finding their way into local waterways.
Overall, much of the recent focus on sewage sludge has been to improve its perception by the public. Referring to it as "biosolids," or branding efforts to present it in a more favorable light may improve the image to some degree, but at some point, it's the equivalent of putting lipstick on a pig. Instead, those in the industry should provide meaningful steps to provide the public and environment protection.