Okeechobee News: Human waste contributes to nutrient overload

Article Posted on September 12, 2018

OKEECHOBEE — Residuals. Biosolids. Outfall.

Calling human waste by any other name does not make it smell sweeter … or reduce the nutrient load … or lessen the impact on Florida’s environmentally-sensitive waters, of the excrement flushed away by Florida’s 21 million residents and 113 million annual visitors.

Ever wonder what happens to the “waste” after you flush?

Even when the waste is treated to kill pathogens (like fecal coliform bacteria), the phosphorus and nitrogen content contributes to the high nutrient load that winds up in waterways, helping to fuel algal blooms. Also, consider the pharmaceuticals, artificial sweeteners and household chemicals in the waste that wind up in the waterways.

Over the years, the Florida Legislature has passed some restrictions on the disposal of human waste. But such laws usually take a long time to phase in, and it seems no matter how well-meaning the legislation’s original author, someone always manages to add a loophole.

According to the Florida Department of Environmental Protection, biosolids are the solid, semisolid or liquid material produced during the treatment of domestic wastewater. Biosolids are also called “sewage sludge” according to FDEP.

Per FDEP, a wastewater treatment facility can choose from several use or disposal options for biosolids including:

• Landfill;
• Transfer to another facility;
• Land application;
• Distribution and marketing as fertilizer;
• Incineration; or,
• Bioenergy.

According to FDEP, most utilities use the land application, landfill or distribution as fertilizer options.

In 2010, the Florida Department of Environmental Protection (FDEP) formally adopted new rules for the management of wastewater biosolids. The rule includes major revisions to the old management system, most notably requiring permits for land application sites and changing the term “Domestic Wastewater Residuals” to “Biosolids.”

Note: “Treatment” refers to reduction of pathogens. Treatment does not affect the nutrient content.

The permitting deadline for biosolids land applications sites was Jan. 1, 2013.

In addition, the Northern Everglades and Estuaries Protection Plan, passed by the Florida Legislature in 2007, restricting landspreading of biosolids in the Lake Okeechobee watershed by 2013. The use of biosolids is not banned completely, even in sensitive watersheds. The statute states that: “The department (FDEP) may not authorize the disposal of domestic wastewater biosolids within the Lake Okeechobee watershed unless the applicant can affirmatively demonstrate that the phosphorus in the biosolids will not add to phosphorus loadings in Lake Okeechobee or its tributaries. This demonstration shall be based on achieving a net balance between phosphorus imports relative to exports on the permitted application site. Exports shall include only phosphorus removed from the Lake Okeechobee watershed through products generated on the permitted application site. This prohibition does not apply to Class AA biosolids that are marketed and distributed as fertilizer products in accordance with department rule.”

According to the University of Florida Institute of Food and Agricultural Services (IFAS), adding biosolids as a soil amendment can be more efficient and better for the environment than using chemical fertilizers. However, according to studies by Florida Audubon, before the state law changed, landspreading was done on a scale that added hundreds of times the nutrient load required to adequately fertilize the land. The goal of landspreading biosolids was not to improve the soil; the goal was to get rid of the waste in the least expensive way possible.

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