Lakeland City Commissioners recently voted to spend $120,000 on a six-month study to see if it’s worth constructing a composting facility with the idea of turning the waste into something far more profitable.
The board voted unanimously to hire Tampa-based GeoSyntech Consultants to perform the six-month study into whether it’s worth building a $20 million composting plant to turn human waste into valuable fertilizer.
“The analysis will include a cost-benefit evaluation, taking into account initial set-up costs,” Assistant City Attorney Alex Landback said.
The facility would combine human waste — or biosolids — with yard waste, creating a nutrient-rich soil mix.
Lakeland produces about 230 tons of biosolids each month. Some of it is already used for low-grade fertilizer.
“Our process for processing the biosolids meets all required regulations before this is ever put into the composting process,” City Attorney Palmer Davis said.
The problem with biosolids is that most municipal treatment facilities are not able to remove the many chemicals found in sewage. The four main categories of potential pollutants – nutrients, pathogens, toxic organics, and heavy metals – behave differently and cannot all be managed by any single kind of treatment. The goal of “safe management” of such a complex toxic mixture cannot be met at a reasonable cost.
Still, the rest, and tons of it, has to be hauled to the local landfill at taxpayer expense.
The idea is to waste less waste by making the poop profitable, all without creating too much of a stink in the surrounding community.
“With it being right there so close to our neighborhood I’m just really concerned about worse smells if possible and longer amounts at times. Especially longer,” neighbor Michael Wingate said.
The study will also look at how much of an odor the process might generate.
Per the first requirement of CWA section 405(d) which requires EPA to establish requirements and management practices for the use and disposal of sewage sludge (biosolids), EPA issued the regulations found in 40 CFR Part 503.
40 CFR Part 503, Standards for the Use or Disposal of Sewage Sludge, regulates sewage sludge that is applied to land, fired in a sewage sludge incinerator or placed on a surface disposal site. It includes pollutant limits, requirements for pathogen and vector attraction reduction, management practices, monitoring, recordkeeping, and reporting among other requirements. 40 CFR Part 503 applies to any person or treatment works that prepares sewage sludge, applies sewage sludge to the land, fires sewage sludge in an incinerator, and the owners and operators of surface disposal sites.
Biosolids Uses
Each year publicly owned treatment works (POTWs) are required to summarize their management practices and provide pollutant monitoring data in Biosolids Annual Reports. These reports are submitted to the permitting authority, either the EPA or state environmental agency. Currently, the EPA receives reports from the 41 states where EPA is the permitting authority and implements the federal Biosolids Program. There are nine states ((Arizona, Idaho, Michigan, Ohio, Oklahoma, South Dakota, Texas, Utah, and Wisconsin) that are authorized through the National Pollutant Discharge Elimination System (NPDES) Program to be the permitting authority for biosolids. EPA will transition to electronic reporting for the remaining authorized states as part of Phase 2 implementation of the NPDES eRule by December 2025. For more information on authorization visit the link: NPDES State Program Authorization Information.
Annual Biosolids Reports are required to be submitted by larger POTWs that land apply, incinerate, or dispose of their sewage sludge via surface disposal. The EPA collects annual biosolids reports from roughly 2,500 larger facilities in the U.S.
Annual reports are collected from Publicly Owned Treatment Works (POTWs) that:
- serve 10,000 people or more;
- are Major POTWs (POTWs with a design flow rate greater than or equal to one million gallons per day);
- are Class 1 management facilities (POTWs with an approved pretreatment program or facilities that have been classified as such by the EPA or state); or
- are otherwise required to report by EPA or permitting authority.
Based on the reports from the facilities that meet the applicability requirements in states where EPA is the permitting authority, the EPA estimates for 2022:
- Managed: ~3.76 million dry metric tons (dmt) of sewage sludge
- Land applied: ~2.12 million dmt
- Applied to agricultural land: ~1.17 million dmt
- Applied to reclamation areas: ~39,000 dmt
- Other (e.g., home garden, landscaping, golf course etc.): ~906,000 tons
- Incinerated: ~600,000 dmt
- Landfilled: ~1 million dmt
- Disposed of in a municipal solid waste landfill (MSW): ~895,000 dmt
- Surfaced disposed of in a monofill: ~111,000 dmt
- Other management practices (examples include deep well injection and storage): ~40,000 dmt
The EPA does not receive data from smaller facilities or those that use or dispose of their sewage sludge using alternate management practices (like landfilling) except for voluntarily submitted information. The EPA believes these smaller treatment facilities tend to landfill sewage sludge, store solids in lagoons, or transport untreated solids to larger wastewater treatment plants. Because the EPA does not receive data from states that are authorized to implement the biosolids program or from smaller facilities, there is no definitive source that reports the amount of biosolids produced annually in the United States. The EPA tries to ensure the information presented here is as accurate as possible; however, the data in biosolids annual reports may contain errors as submitted by the POTWs.
Types of biosolids land application:
Agriculture
40 CFR Part 503.14 requires that biosolids must be applied to land at the appropriate agronomic rate which is the sludge application rate designed to provide the amount of nitrogen needed by the crop or vegetation grown on the land. Agronomic rate is dependent on crop type, geographic location, and soil characteristics. Assistance in designing the agronomic rate should be obtained from a knowledgeable person, such as the local extension agent or the soil testing department at the Land Grant University in each state.
Reclamation Sites
Biosolids have been used successfully to establish sustainable vegetation, reduce the bioavailability of toxic substances often found in soils, control soil erosion, and regenerate soil layers at sites that have damaged soils. Soil regeneration is very important for reclaiming sites with little or no topsoil.
Forestry
Biosolids have been found to promote rapid timber growth, allowing quicker and more efficient harvest of an important natural resource.
Lawns and Home Gardens
Biosolids that meet the most stringent pollutant, pathogen and vector attraction reduction requirements may be purchased by the public from hardware stores, home and garden centers or their local wastewater treatment plant. For more information on where to purchase biosolids in your area, contact your local utility or state environmental agency.
Assessing Pollutants Found in Biosolids
Assessing the potential risk of pollutants found in biosolids is the top priority of EPA’s Biosolids Program. EPA identifies pollutants found in biosolids through open literature reviews and sewage sludge surveys in order to assess their potential risk to public health and the environment. More than 700 pollutants have been found to occur in biosolids (in at least one instance) since EPA began tracking their occurrence in 1993 when 40 CFR Part 503 was promulgated. Not all of the approximately 700 pollutants that have been found in biosolids will be present in every wastewater treatment facility. Pollutants found in biosolids will vary depending upon inputs to individual wastewater treatment facilities over time. The presence of a pollutant in biosolids alone does not mean that the biosolids pose harm to human health and the environment.
Rolf Halden is a professor at Arizona State University, member of the adjunct faculty at Johns Hopkins, and an expert on the environmental impacts of industrial chemicals. His lab recently used treated sewage sludge to identify and prioritize persistent bioaccumulative chemicals The study found that chemicals contributed between 0.04% – 0.15% of the total dry mass of biosolids produced in the USA annually, which is equivalent to 2,866 – 8,708 tons of chemicals. The top individual chemicals found included:
- Brominated fire retardants
- DecaBDE
- pentaBDE
- 1,2-bis(2,4,6 tribromophenoxy
- ethane
- Surfactants
- Nonylphenol (NP) and their ethoxylates (NPEOs) – both used in textile processing
- Antimicrobials
- Triclosan and triclocarban
- Antibiotics
- Azithromycin
- Ciprofloxacin
- ofloxacin