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Accept the 2025 Annual Biosolids Land Application Report from the Department of Resource Management
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Published Notice Required? Yes ___ No _X _
Public Hearing Required? Yes ___ No _X _
DEPARTMENTAL RECOMMENDATION:
The Department of Resource Management recommends that the Board of Supervisors accept the 2025 Annual Biosolids Land Application Report.
SUMMARY:
Solano County Code, Chapter 25, requires that a report be submitted annually to the Board of Supervisors presenting the results of the past season’s activities on the land application of Class B biosolids in Solano County. The report must also include an update on the generator’s progress toward utilizing alternative technologies for the reuse of biosolids other than land application or landfilling. The report documenting the results of the 2024 season for the land application of biosolids in Solano County is provided as Attachment A.
FINANCIAL IMPACT:
The cost of managing and overseeing the biosolids land application program is typically recovered through fees collected for site registration and land spreading charged to the applicant. Costs for biosolids material sampling and sample analysis are also charged to the applicant. A per-acre surcharge for research, charged to the applicant, is used for conducting research activity to improve understanding of potential impacts, if any, of the land application of biosolids. However, biosolids class B land application has not occurred in Solano County during the past year.
The costs associated with preparing this agenda item are nominal and absorbed by the Department’s FY2025/26 Working Budget.
DISCUSSION:
Solano County is one of the few California counties that regulate the land application of biosolids onto agricultural land as a soil amendment. Since 1997, Department of Resource Management (DRM) staff have implemented the local biosolids land application program by enforcing Solano County Code (SCC) Chapter 25 which incorporates the requirements contained in CFR 50, Part 503 of the federal standards. SCC Chapter 25 was amended between 1998-2012 to include various requirements such as public notification for land-spreading activity, wet weather restrictions on biosolids land application and spreading, prohibition on the application of biosolids within primary and secondary marsh areas, and expansion of soil and ground water testing related to biosolids land application. These amendments to SCC Chapter 25 have provided additional public health and environmental protections regarding the use of biosolids. This program is recognized nationally, and is focused on increased public participation, research partnership and proactive enforcement of standards.
During the 2024 biosolids land application season, there was no land application of Class B biosolids as a soil amendment in Solano County. This cessation in land application is attributed to the acquisition of properties utilized for biosolids land application by Flannery & Associates. Flannery & Associates have curtailed the land application of class B biosolids on properties they own and have indicated their properties will not be available for class B biosolids land application at this time.
Several odor complaints were received in July and August 2024 and were attributed to the class A biosolids fertilizer land application operations conducted by Lystek. These complaints occurred in the area of eastern, unincorporated Vacaville. Staff continue to explore mitigation measures for Lystek, to prevent reoccurrence of odor nuisance issues associated with the use of Lystegro fertilizer. Since all of the odor complaints received were related to the land-spreading of Lystegro, staff are exploring options to identify potential mitigations, including possible revisions to SCC Chapter 25.
The report also references the 2024 Bay Area Clean Water Agencies (BACWA) annual report (Attachment B) that provides an update on the generator’s progress toward utilizing alternative technologies for the reuse of biosolids other than land application or landfilling and the outcome of the stakeholder meeting held on March 6, 2025.
ALTERNATIVES:
The Board of Supervisors may choose not to receive the 2024 Biosolids Land Application Report. This is not recommended as the report is provided in accordance with Solano County Code and details the activity of the Department relative to the land application of biosolids in 2024.
OTHER AGENCY INVOLVEMENT:
In obtaining information for this report, the Department consulted with County Counsel, County Administrator’s Office, County Agricultural Department, UC Cooperative Extension, US Environmental Protection Agency, the San Francisco Bay Area and Central Valley Regional Water Quality Control Boards, Synagro LLC, Lystek International Inc., and the Biosolids Stakeholder Group (included representation from interested constituents from the Rio Vista and Suisun areas of Solano County), East Bay Municipal Utilities District, Fairfield-Suisun Sewer District, Union Sanitary District and the City and County of San Francisco Public Utilities Commission. Information contained in the 2024 Annual Biosolids Land Application Report is distributed to participants in the Biosolids Stakeholder Group.
CAO RECOMMENDATION:
APPROVE DEPARTMENTAL RECOMMENDATION