1 slop oil gutter oil pretreatment a basic understanding of slop oil, also known as driving oil, for the regional differences in designation. Swill oil refers to short-term catering waste, a variety of leftovers in a mixture of oil, similar to the state of the rural traditional pig preparation of slop. Swill oil varies depending on the length of time, the amount of leftovers, the amount of non-nutritive impurities such as plastic and chopsticks, as well as the length of time and the degree of corruption. Fresher slop oil, such as food frying waste oil, waste hot pot oil, fresh leftovers contained in the oil itself still has a normal oil flavor. With the prolongation of time, a variety of dirt mixed and corruption to destroy the quality of waste oil, so that slop oil gradually deteriorate, dirty and smelly. The gutter oil refers to the oil recovered from the catering back row waste gutter grease trap, itself has been seriously deteriorated, has completely lost the quality of slop, full of bad smell, but after treatment can still recover the oil containing oil mixture, is the quality of serious bad waste oil and grease