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July 2, 2009 <br /> Project Number 19.09 <br /> FOR: Mr. Eric Jenssen <br /> Vice President, Engineering <br /> Trinchero Family Estates Wines <br /> Post Office Box 248 <br /> St,Helena, California 94574-0248 <br /> PROJECT: Trinchero Family Estates Winery <br /> 18667 Jacob Brack Road <br /> Lodi, California 95242 <br /> SUBJECT: Septic Tank Investigation <br /> INTRODUCTION <br /> Chesney Consulting has been requested by Eric Jenssen to provide information'on new septic tanks <br /> to be installed at the Trinchero Winery fac' ily. These new tanks may be installed for the following <br /> four locations: the Crush Office Buildin , the Dry Goods Storage Buildint, the Guard/Scale HOaSL'- <br /> Buildings,and Office Trailcr Buildings/Presently, wastewater influent(blackwater and graywater) <br /> flows tinder gravity from these buildings into concrete tank lift stations with comminutor(grinder) <br /> pumps. This effluent is then dispersed through a mound disposal system. <br /> The ultimate objective is to prevent organic particulate matter from being discharged into the soil <br /> environment. By installing new septic tanks ahead of the lift stations to retain solids,only clarified <br /> effluent would be pumped to the centralized disposal location. Conversely, if influent from the four <br /> locations is pumped by the existing lift stations, solid material must then be retained by a single, <br /> large septic tank before dispersal. Influent pumped by a grinder pump does not readily separate into <br /> sludge, scum and clear zones if the influent contains a high volume of solids material. However, if <br /> there is a comparatively low volume of solids, a long distance from the inlet to the outlet creating a <br /> longer detention time within the tank, and if filters are used at the outlet of the new tank(s) installed, <br /> particulate matter can be retained and managed by the filtration system. <br /> Because of the expense involved of installing four separate tanks (approx. 2.5x the cost vs. <br /> installing a single large tank),consideration is given in this report to installing one single, large <br /> septic tank to receive the pumped influent frons the four locations. This large tank would retain the <br /> pumped influent solids through the two methods referenced above: sufficient detention time <br /> (hydraulic residence time within the tank) and passive filtration. The clarified effluent would then <br /> be pumped to a new disposal area via a Filtered lift station. <br /> Page 1 of 7 <br /> P. O. Box 3794 • 9'urt'ock, Cil 95381 • Office (209) 668-1403 • Fax (209) 668-2598 <br />