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F E INTERCEPTOR AND CONVENTIONAL SEPTIC TANKAGE terceptor Tanks rceptor tankage has been designed to capture and ultimately reduce the oil, grease r drain influent concentrations originating from the Restaurant. The internal plumbing of the tanks is not the conventional septic tank configuration, but rather conducive to trapping grease due to elongated inlet and outlet tees and a horizontal "S" curve crossover pipe. The exact location of the existing influent pipe along with its slope, depth, and diameter are unknown at this time. However, it is known that the piping from the kitchen extends from near the southern end of the restaurant building,while the human waste piping is near the northern end of the building. Consequently, when the location of these lines are determined, the tankage to be installed will obviously require alignment with this piping. Upon removal of the existing tanks, both influent lines should be inspected and observed for clogging and general conditions. The grease interceptor tanks will consist of three tanks, all two compartments, orientated in series to increase detention time. Since there will be instantaneous peak flows,the first tank will be an H-20 traffic rated 2,000 gallon grease tank. This large volume tank is beneficial in achieving a high degree of oil and grease separation. Two smaller, H-20 traffic rated 1,250 gallon grease tanks will follow this initial 2,000 gallon tank, for additional O+G retention. In the second chamber of the last tank, a Polylok PL-625 Grease Trap Effluent Filter is to be installed. After effluent travels through this filter, it travels through a connection pipe into the side of the second chamber of the 5,000 gallon conventional septic tank, as discussed below. B. Conventional Septic Tanks Influent from the Restaurant's restrooms will gravity flow to an H-20 traffic rated, 5,000 gallon, two compartment conventional septic tank. As stated, the influent line location is unknown and will be determined upon removal of the existing tanks. As with the kitchen influent line,the restroom influent line should be inspected for clogging and general conditions. The hydraulic residence time, or volumetric capacity of the tank, should be approximately equal to 5 times the average daily flow. The total ADF was determined to be 1,360 gpd, with an unknown percentage of the total waste stream influent volume originating from the restrooms. With the kitchen waste stream treatment already accounted for from the grease interceptor tankage and using assumed 50150 flow volumes between the kitchen and restrooms, we find the following: 1,360 gpd 2 = 680 gpd from the restrooms x 5x ADF =3,400 gallons. Although the grease tank effluent will be flowing into the second compartment of the 5,000 gallon tank, it has already been treated by the grease interceptor tankage. Therefore,the 5,000 gallon tank is ample volume to create a residence time of 5x the ADF. When accounting for a typical peaking factor for commercial systems,we still find adequate tank size: 3,400 x 1.5 Peaking Factor= 5,100 gallons. A Polylok PL-250 Effluent Filter is to be installed at the sanitary tee outlet of the 5,000 gallon conventional tank, before the effluent gravity-flows to the first polishing tank. Page 4 of 8 Chesney Consulting