External Passive Twin grease Traps Chinese Restaurant

Passive twin tank grease trap installed at a Chinese restaurant. The external grease traps are connected to 4 sinks & a wok cooker. The owner of the restaurant did not have the space inside the kitchens and requested the grease trap was installed outside. Because of the high amount of grease being produced by the restaurant we decided to install a twin tank system primary & secondary so any grease residue missed by the first tank would be trapped in the second tank.