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F' - Uti Sap-21 -98 05 : 15P I I CytoCulture Report on Batch Inoculation and Gallery Installation 3 iLACCO Site, Mountain View,CA for Noreal Waste systems, Inc. December 19, 1995 After approximately three hours of pumping (estimate 30,000 gallons of water discharged to the sanitary sewer), Ramcon, under the direction of CytoCulture, utilized the extend-a-hoe to excavate an infiltration gallery trench approximately 25 feet in length along the south wall The trench was cut approximately 2 feet below the floor of the excavation A small amount of gravel was spread in the trench before the horizontal piping was lowered into the trench and covered with gravel The lowest point of the gallery trench was excavated at th', south east corner. allowing the vertical well user to extend to approximately 12 feet below grade Construction of the extraction gallery proceeded in a similar fashion, except to install the extraction riser at a lower depth than the infiltration riser to improve the hydraulic connection with the sand layer and the aquifer Due to the amount of rainwater that had been standing in the excavation, the side walls were very unstable and sidewall cave-ins were a reoccurring problem The extraction gallery vertical riser and horizontal piping was installed at approximately 12 5 feet below grade for approximately 40' along the north wall Backfilling of the gallery was accomplished in the same manner as the infiltration gallery The extraction well riser was positioned in the northwest corner of the excavation diagonally across and down-gradient from the infiltration trench well riser in the southeast corner of the ex cavation • This positioning of the infiltration and extraction risers should optimize future recovery and reinfiltration of groundwater parallel to the prevailing groundwater gradient at the si e An "As Built" drawing for the interim extraction/infiltration piping layout for the excavation areas has been included (Figure 3) to provide plan and sectional views of the installation This installation is likely to serve as the future infiltration gallery for the proposed ground water bioremediation system under consideration by Fugro West, Inc and CytoCulture Batch Culture Inoculation The batch culture of hydrocarbon-degrading bacteria was adjusted to 6 8 before proceeding with the batch inoculation of the excavation Utilizing a single submersible pump aild 1 5' hose, the inoculum was dispersed over the excavation according to the Work Plan Approximately 50% was sprayed over the excavation and the remaining half was directed along the south wall of the excavation over the newly installed infiltration piping sy,tem The addition of the inoculum through the infiltration system allowed for the cultures to be placed directly in the area along the south wall, favoring the southeast corner where higher concentrations of petroleum hydrocarbons had been reported The water was introduced into the excavation at an average rate of 12 gallons per minute Sampling and Analysis . Prior to the addition of the batch culture to the excavation pit, CytoCulture collected a grab sample of the excavation water from the southeast corner after the infiltration gallery was