The winery and olive process wastewater system utilizes initial screening provided by screened baskets and strainers installed on the trench and floor drains within the facility. Screen opening sizes will be on the order of ¼-inch for exterior drains, to catch leaves, stems, etc. and 1/8-inch for interior drains, to catch pulp. A gravity collection system was designed such that all piping has a minimum slope of 2% or ¼-inch per foot. The olive processing facility only is equipped with a two-compartment grease trap prior to entering the process wastewater treatment system. A motorized solids removal screen removes the large solids from the system and as a result, reduces the organic biological loading on and the accumulation of solids in the treatment system. Solids from the screening operation will be treated as pomace
The process wastewater pump sump and holding tank are designed to handle one days flow and are equipped with a duplex pump sump capable of pumping all of the anticipated process wastewater flow with one duty and one standby pump that can alternate functions. The duty pump would be used for all but the most extreme flow conditions. The second (standby) pump would be activated during peak hour events or similar events of infrequent occurrence and short duration. Storage in the pump sump would provide an additional factor of safety. A PVC force main to the treatment system will be sized to be adequate for the peak flow rates anticipated from the pump station. The pumps convey the process wastewater to the treatment system.
Pretreatment and pH neutralization will be achieved though the filtration of oyster shells to reduce the acidity of the winery and olive process wastewater. The oyster shells will be contained in a chamber located in the process wastewater pump sump. The pH adjustment provides a more favorable environment for the growth of aerobic bacteria in the treatment system and will reduce the chance for emission of hydrogen sulfide odors that can occur in an acidic environment. The pH of the system shall be monitored for a year, as required by the San Francisco Bay Regional Water Quality Control Board, especially through one harvest season.
An in-line measurement device is installed to measure flows from the process wastewater pump station to the treatment system. Additional flow measuring devices are installed to measure flows from the holding pond to the land disposal system. A filter will screen secondary effluent prior to vineyard irrigation.
Biological stabilization will occur in the mechanically aerated facultative-aerobic pond. Surface mechanical aerators for the aeration ponds have been sized to satisfy biochemical oxygen demand as well as oxygen dispersion requirements. This pond system is large enough to provide a normal residence time of 140 days at average day peak harvest month flow conditions. This residence time is greater than the 90 to 120 days detention time recommended for these types of systems. For ultimate process wastewater / rainfall inputs and evaporation / irrigation outputs the pond water balance is based on the maximum average monthly rainfall from the previous 10 years. The total volume of the pond system is approximately 0.209 MG in addition to 2 ft minimum freeboard.
