For Vintners Inn
Santa Rosa, California

In 1983, we performed the engineering analysis and design of a large "mound" wastewater disposal system for a 45-unit wine country inn and restaurant near Santa Rosa (12,500 gpd capacity). The unique design required detailed analysis of groundwater hydraulics and potential nitrate impacts. In 2000, Questa completed the engineering work for additions to the project, including additional lodging, restaurant expansion, and conference facilities. This required replacing the original mound system with a small onsite wastewater treatment plant, storage pond, and subsurface drip irrigation-disposal system. The new system was designed for a capacity of 32,000 gpd and includes a pressure sewer collection system, septic tank and equalization tank for primary treatment, an aerobic treatment unit (FAST system), chlorine disinfection, and winter storage pond, followed by seasonal re-use of the treated water for subsurface drip irrigation of 65 acres of vineyards. The new facilities operate under permits issued by the North Coast Regional Water Quality Control Board and Sonoma County Permit and Resource Management Department. The system was put in service in 2003 and produces an advanced secondary-quality effluent, with BOD, total suspended solids, and total nitrogen levels all below 10 mg/L.