The Sacramento Regional County Sanitation District (District) engaged the private sector for the design, finance, construction, ownership, and 20 year operation and of a Biosolids Recycling Facility (BRF). In early 2005, the BRF began processing solids into heat dried pellets to be beneficially reused. The BRF is located at the Sacramento Regional Wastewater Treatment Plant (SRWTP), which is a 181 MGD regional facility utilizing a primary and secondary pure oxygen biological wastewater treatment process.
Compared to the conventional design-bid-build approach, the design-build-own-operate public/private partnership is delivering measurable benefits to the District in the form of cost savings, schedule efficiency, financing flexibility, technical innovation and a balanced transfer of risk. The addition of the BRF to the other District biosolids management options is providing a diversified and reliable biosolids program.
The Sacramento Regional County Sanitation District (District) has implemented a unique project with the private sector in an innovative application of biosolids management techniques. In order to comply with a regulatory directive, while attempting to achieve a balanced portfolio of biosolids management options that include beneficial reuse, the District has chosen to implement California’s first Design-Build-Own-Operate (DBOO) project for a biosolids application.
Specifically, the District has engaged the private sector for the design, construction, operation and ownership of a Biosolids Recycling Facility (BRF). Compared to the conventional designbid-build approach, the DBOO public-private partnership model is yielding measurable benefits to the District in the form of cost savings, schedule efficiency, financing flexibility, technical innovation and a balanced transfer of risk.
In early 2005, the BRF began processing a minimum of 20 dry tons of biosolids per day, transforming digested solids to a marketable, “beneficial reuse” product. Via a competitive procurement process, the District has contractually engaged a private contractor to finance, design, construct, own and operate the BRF for a period of 20 years. The procurement process involved the development and issuance of multi-stage technical bidding documents that described the BRF requirements in terms of performance standards mandated by the District. Through the issuance of both a Request for Qualifications (RFQ) and a Request for Proposals (RFP), the evaluation process ensured the District selected only the most proven and qualified team for implementation of this project.
The Sacramento County Regional Sanitation District, formed in 1973, provides wastewater conveyance and treatment to businesses and residents in the urbanized areas of Sacramento County, California. The District owns and operates the Sacramento Regional Wastewater Treatment Plant (SRWTP), a 181 million gallon per day (MGD) primary/secondary treatment facility serving more than 250 square miles and over 1.2 million residents. The District continues to grow, with up to 8,000 new customer connections to the system each year.
The SRWTP utilizes a primary/secondary pure oxygen biological wastewater treatment process. Anaerobically digested primary and waste activated sludge is stored for up to five years in facultative sludge lagoons called Solids Storage Basins (SSBs). The biosolids are then “harvested” by District staff and pumped to Dedicated Land Disposal (DLD) units where they are injected below the soil surface to complete the treatment and disposal process. The SRWTP currently produces approximately 27,000 dry tons of anaerobically digested biosolids annually.
The Central Valley Regional Water Quality Control Board (RWQCB) mandated that the District’s use of unlined DLD units posed a threat to groundwater quality in the area. Subsequently, the RWQCB required the District to discontinue use of the unlined DLD units by November of 2001.