New Wastewater Treatment Plant

The City of Ridgecrest (City), located in the eastern portion of Kern County, desires to upgrade its current WWTP on land owned by the United States Department of the Navy (Navy) and would serve both the City of Ridgecrest and NAWS China Lake. As such, the Navy has served as a collaborator with the City in the production of this document. The Navy is also preparing a separate document in accordance with the National Environmental Policy Act. The Ridgecrest New WWTP Modified Project (Project) would be constructed adjacent to the existing WWTP, utilizing very little of the existing facility. The site is located on NAWS China Lake, approximately 3.5 miles northeast of the City center. The City has held an agreement with the Navy for an approximately 352-acre easement to operate a WWTP and 11 facultative treatment ponds on Navy-owned land since 1974, with the most recent modification of the contract on February 7, 1994. Two of these 11 ponds are out of service. In order to accommodate the expansion of the existing WWTP, the City requested, and was granted in 2020, an extension of the existing easement to include an additional 7.67 acres to the west of the existing WWTP. The Project would result in the construction of an upgraded WWTP to meet future residential and commercial growth through approximately 2050, repair existing treatment pond infrastructure, and improve the quality of the wastewater treated at the facility. Existing Conditions The existing WWTP has a permitted capacity of 3.6 million gallons per day (mgd), with a daily maximum discharge of 3.6 mgd. While the facility is rated for a maximum capacity of 3.6 mgd, the facility is aging and is not expected to be able to accommodate flows that would meet its permitted capacity. In 1993 daily flow reached approximately 3.3 mgd; however, due to a decrease in population and implementation of water conservation in conformance with California and local policy, daily flow levels (as of 2020) have declined to approximately 2.2 mgd. Additionally, in 2019 several earthquakes occurred which affected the area, causing damage to the distribution system of the 11 facultative treatment ponds located at the NAWS site. Under current operations, treated water is percolated into the underlying aquifer through the treatment ponds located at the NAWS site and the former City WWTP site, located approximately 3.25 miles southeast of the Project site. Additionally, recycled water that has undergone primary and secondary treatment is used for irrigation at the China Lake Golf Course, approximately one-quarter mile southeast of the Project site. The Navy disinfects the effluent before it is used for irrigation purposes. Under the City’s contract with the Navy to operate the WWTP, the Navy is allotted 525 acre-feet per year (AFY) of treated water, which is further treated within a sand filter prior to disinfection by the Navy and then used for irrigation purposes on the golf course. Previous Analysis and Approval A previous version of this Project was analyzed in an EIR that was certified by the City Council on July 6, 2016 (SCH No. 2015061095). The previous EIR analyzed two alternatives for the expansion of the City of Ridgecrest wastewater treatment plant (WWTP), from which the current Project differs. Alternative 1 proposed to demolish the existing WWTP and construct a new, upgraded facility on the same site, as described in Section 2.1.6, and also proposed the City to construct several new treatment ponds where the four percolation ponds currently exist in the southeastern portion of the City. Alternative 2 proposed the expansion of the treatment ponds at the NAWS China Lake site, the construction of an expanded gravity main pipeline, and the construction of a new WWTP south of the four existing percolation ponds in the southeastern portion of the City, along with several new treatment ponds at this site. Both of these alternatives proposed treatment ponds to be located within San Bernardino County, across the street from the nonoperational City WWTP. Project Scope Change Following certification of the EIR, the City and Navy continued to discuss the Project and eventually came to an agreement that the scope of the Project should change, deciding to upgrade the WWTP to be constructed adjacent to the existing facility. This would necessitate the removal of most of the existing facility. The upgrade and ultimate expansion of the existing facility would require the development of approximately 7.67 acres of land to the west of the current facility. This land has been added to the existing easement between the Navy and the City for construction of the improved WWTP. The Certified EIR analyzed a 3.6-mgd (average daily flow) wastewater facility, while the fully completed Project would construct a facility that can process up to 5.4 mgd (average daily flow). This was not previously analyzed in the Certified EIR. This Addendum analyzed processing up to 5.4-mgd but did not analyze disposal of this amount. Upon full buildout of the facility, it would only be able to dispose of up to 3.6 mgd (as this is what will be requested in the Report of Waste Discharge for the new plant). This Addendum only analyzes disposal of up to 3.6 mgd. Additionally, the proposed Project includes the future construction of pond 12. This pond is within the existing easement between the Navy and the City but was also not analyzed in the Certified EIR. The improvements would result in the construction of a new facility that would utilize primary clarifiers, extended aeration with activated sludge (oxidation ditches), secondary clarifiers to treat the wastewater, along with anaerobic digesters and cogeneration facilities to utilize the resulting biogas from the anaerobic digesters for power production. Further, the Project includes repairs to the existing infrastructure of the 11 treatment ponds that were damaged by earthquakes in 2019. While three other alternatives were presented in the EIR (not provided or discussed in this document), the current Project has been deemed the most appropriate and includes considerations such as cost, usability, maintenance, and lifespan of the equipment. Removed Project Components The proposed Project no longer includes the following components: • Construction of several new treatment ponds where the four percolation ponds currently exist in the southeastern portion of the City. • Irrigation of approximately 30 acres of alfalfa located 3.25 miles southeast of the Project site, at the former City WWTP. • The construction of an expanded gravity main pipeline. • The construction of a new WWTP south of the four existing percolation ponds in the southeastern portion of the City, along with several new treatment ponds at this site. No construction will take place in San Bernardino County. All construction will now take place on the NAWS site through an easement that the Navy has granted to the City.