GRASS VALLEY WASTEWATER TREATMENT PLANT DENITRIFICATION AND UV DISINFECTION FACILITY PROJECT Draft Initial Study and Proposed Negative Declaration PLEASE NOTE - this document was adopted by City Council on August 28, 2007 via Resolution 07- Comments and / or questions regarding the document may be directed to:  Timothy M. Kiser, Director of Public Works / City Engineer City of Grass Valley 125 East Main Street Grass Valley, CA 95945 (530) 274-4351 Telephone (530) 274-4399 Fax timk@cityofgrassvalley.com Copies of the document are also available for public review during regular business hours at the at the Grass Valley City Hall, Department of Community Development, 125 East Main Street, Grass Valley PROJECT DESCRIPTION The City of Grass Valley (City) Public Works Department operates a wastewater treatment plant (WWTP) that provides sewer service to 12,100 residents and 1,700 businesses. The City is proposing to implement improvements to the facility to improve water quality of its effluent discharge to meet new requirements from the Central Valley Regional Water Quality Control Board (RWQCB). The current project consists of the construction of improvements to the biological nitrogen removal process to meet nitrogen discharge limits and the addition of ultraviolet (UV) disinfection facilities for removal of fecal coliform to meet new discharge requirements for cyanide and trihalomethane (THMs) at the WWTP. The project will be constructed within the boundaries of the City's existing WWTP. The proposed project consists of:   Removal/decommissioning of existing chlorine gas disinfection equipment; Installation of UV disinfection facility in an existing chlorine contact basin; Addition of a sodium hypochlorite feed system for the non-potable water system; Installation of launder covers on one of the secondary clarifiers; Installation of covers on the tertiary filters and other yard structures; and Installation of air piping to improve denitrification facilities. The air piping modifications will provide greater process control during periods of low influent flow to the WWTP to improve the ability to meet existing nitrogen limits. With the removal of the chlorine disinfection facilities and the addition of the UV disinfection, the THM and cyanide limits will be met. Public Review Period began on July 17, 2007 and closed August 17, 2007 DOCUMENTS Report Cover and Table of Contents (0.147MB) Proposed Mitigated Negative Declaration (0.078MB) Project Description (0.172MB) Initial Study Environmental Checklist Form (0.248MB) References (0.032MB) Attachment 1: Figures Figure 1: WWTP Project Location (0.743KB) Figure 2: WWTP Project Elements (0.380MB) Figure 3: CNDDB Species in the Project Area (0.686MB) Figure 4: Geologic Units in the Project Area (0.385MB) Figure 5: Soils in the Project Area (0.385MB) Figure 6: Regional Fault Map (0.825MB) Figure 7: 100-Year & 500-Year Flood Hazards within the Project Area (0.40MB) Figure 8: Routes to the Project Area (0.605MB) Attachment 2: Wastewater Treatment Plant Description (0.089MB) Attachment 3: Air Quality Conformity Analysis (0.091MB) Attachment 4: Biological Study (0.928MB) Download entire Project document (7.716MB)