A Case for the Safety and Sustainability of Class B Biosolids Land Application – Results of Microconstituent and Pathogen Research in Gainesville, FL

T he city of Gainesville, doing business as Gainesville Regional Utilities (GRU), owns and operates two water reclamation facilities that serve over 160,000 customers within Gainesville and the unincorporated area of Alachua County. As part of the water reclamation process, biosolids are generated andhave been beneficially recycled through sustainable land application practices for over 27 years at Whistling Pines Ranch (WPR), a 1,100-acre farmwest of the city of Archer in the southwest part of the county (see Figure 1, page 6). The biosolids replace or supplement inorganic fertilizer used to grow a variety of forage and row crops, and they also act as a soil amendment to the typically sandy soils at the site. GRU’s biosolids land application program is permitted by the U.S. Environmental Protection Agency (EPA) and the Florida Department of Environmental Protection (FDEP) through Section 503 of Title 40 Code of Federal Regulations andChapter 62-640,FloridaAdministrative Code (F.A.C.). The biosolids program has been recognized for its exemplary performance, and GRU was awarded the EPA’s Most Outstanding Biosolids Operation in the Southeast United States in 2004. Also, the Kanapaha Water ReclamationFacilitywas awarded theFDEP2009Plant Operations Excellence Award, which included a section on biosolids program operations. In addition to biosolids treatment for its two water reclamation facilities, GRU provides biosolids treatment and recycling services to the University of Florida and the communities of Hawthorne, High Springs, and Waldo. In order to ensure the long-term capabilities of providing these services, the Gainesville City Commission approved the purchase of a portion of WPR with the condition of obtaining necessary permits. As a result of changes in land use regulations, GRU requested a special exception to the county’s Unified Land Development Code to continue the beneficial use of biosolids. As a condition of the special exception application process, GRU evaluated the potential exposure tomicroconstituents in biosolids applied atWPR.Microconstituents, as termed in this article, include a number of trace organic compounds of interest.Among them are those identified as “endocrine disruptors,” pharmaceuticals, or personal care products. The work to sample and evaluate microconstituents was termed Phase 1 and was developed in conjunction with the Alachua County Environmental Protection Department and the FloridaDepartment of Health (FDOH)/Alachua County. Phase 1 sampling and analysis for microconstituents was performed on the biosolids, biosolids and soil mixture, and groundwater. Phase 2 of the study evaluated exposure pathways fromWPR with regard to pathogens and was developed in conjunction with the County Environmental ProtectionDepartment. Phase 2 consisted of sampling and analysis of (1) bioaerosols for pathogens, (2) transmission of soil metals and radionuclides to groundwater, and (3) vectors (flies, mosquitoes, etc.). Figure 1 is an aerial photograph of the farm with fielddelineation.Local stakeholders typically live in areas to the west of theWPR property. The EPA has established strict rules for the treatment of biosolids, sampling, analysis, and disposal in 40 CFR Part 503 (http://yosemite.epa.gov/r10/water.nsf/ NPDES+Permits/Sewage+S825/$FILE/503032007.pdf). Guidance documents have been added to simplify and aid in the compliance with the rule (EPA/625/R-92/013). The guidance documents outline methodologies for the appropriate analysis and testing of biosolids to ensure that adequate treatment has been performed. The EPA is a significant proponent of the beneficial use of biosolids and has designed the current standards exclusively to maintain the significant benefits offered by biosolids reuse, while continuing its commitment to protecting public and environmental health. The 40 CFR Part 503 rule was based on the results of extensive research, sampling, and analysis, as well as multiple extensive risk assessment studies. In these studies, the traditional risk assessment framework was modified in order to include state-of-the-art technology to evaluate the possible negative health impacts of land-applied biosolids. Research is ongoing, but to date no conclusive evidence has been provided that indicates the 503 rule fails to protect public health as it is currently written and enforced. Subpart D of the 503 rule outlines the specific requirements for the reduction of pathogens within biosolids, as well as their attractiveness to vectors that may harbor additional pathogens. Essentially the EPA essentially named two classes of biosolids: Class A biosolids are not considered to pose a risk to the general public Paul B. Davis, P.E. , is a water/wastewater engineer with Gainesville Regional Utilities (GRU); Ronald G. Herget, P.E. , is GRU’s director of water and wastewater engineering; Richard H. Hutton, P.E. , is a supervising utility engineer with GRU. George Lukasik, Ph.D, is executive director of BCS Laboratories in Gainesville. Patricia V. Cline, Ph.D, is a senior scientist with the engineering firm CH2M Hill in Gainesville; Timothy M. Ptak, P.E. , is a client service manager in the firm’s Gainesville office; Jason Mau, P.E. , is a senior project engineer in the firm’s Gainesville office. Allan H. Biddlecomb, P.G. , is a senior hydrogeologist with the engineering/architectural/scientific firm Jones Edmunds & Associates in Gainesville. Reprinted with permission from Proceedings of the Residuals and Biosolids 2010 Specialty Conference, May 23-26, 2010, Savannah, Georgia, Copyright © 2010 Water Environment Federation: Alexandria, Virginia. This article was presented as a technical paper at the 2010 Florida Water Resources Conference in May.