Restaurant grease is brought into Mendota for processing by Mahoney Environmental. Raw material is emptied out of the trucks into the bulk pit. In the bulk pit, it is heated up to a temperature that lets the liquid drain through a screen in the bottom of the pit. This temperature will not exceed 190 degrees, and is monitored by a probe connected to a chart recorder. While the grease is heating, an auger is run to convey any solid material out. The soild material is then separated with plastic, glass, and metal going to the trash. The fat and bone is then put in the scrap pit for processing in rendering. The liquid is pumped to a roto-strainer where solids smaller than 3/8" are separated, Here glass and gravel are taken out and sent to the trash. The liquid is sent to a settling tank and small particles of fat are sent to the scrap pit. Once the grease is in the settling tank, it is heated up to 212 degrees and let set for 24 hours. This process allows the material to separate into three layers: water, emulsion, and grease. The water is drained off of the bottom and sent to the waste-water operation to be processed. The emulsion, which is water, grease, and solids that won't separate by gravity is sent to the evaporator for processing. The finished grease is checked for acid and solids, and then sent to storage for shipment. All of the emulsion is put into tanks and blended with a percentage of grease to act as a carrier. Once a batch has been made, it is run through the evaporator. In the evaporator, the emulsion is recirculated and heated. There is a 21" vacuum applied to the system, which allows water to flash at a lower temperature. Once the discharge temperature reaches 190 degrees, the water is flashed off in vapor form. The vapors are sent to an air condenser where fans are used to cool the vapors, changing them back into the water, which is sent to waste water for processing. Non-condensables are sent to the boilers to be incinerated. The grease and solids are then sent to the centrifuge where they are separated. The solids are sent to rendering for processing, while the grease is sent to storage. The grease being discharged from the centrifuge is periodically checked for solids. Finished grease is also brought in from outside of the plant. This grease is sent straight to storage. When the grease is in storage, acids are checked and grease is blended together to make the finished product. A sample of the batch is then taken and sent to a lab where it is tested for pesticides, insecticides, and PCB.