the "production" process of waste oil and the collection of "hogwash fat" \ x1d \ x1d \ In most cities, people often see such a scene: a farmer-like man is riding a small truck full of swill, slowly moving forward on the street, dripping swill and a continuous stink of swill make pedestrians on the road. And these disgusting garbage may have been piled up 1 hours ago to prevent waste oil from flowing into a restaurant where food and beverage services are accumulated. The farmer comes here by bike after dinner every day, and then collects the swill and carries it away. In the kitchens of these restaurants, when the manhole cover of waste water is opened, you will see some sticky brown things floating inside, which are a mixture of grease, detergent and rice residue after washing dishes. People call these waste oils "gutter oil". And the farmer's purpose here is to collect these waste oils. He took out the gutter oil bit by bit with a big spoon, and then mixed it into a black iron bucket filled with swill and carried it away. According to a person in charge of Beijing Environmental Protection Bureau, there are about 51,111 hotels, restaurants and canteens in Beijing alone, and 51% of the more than 1,611 tons of swill and 1,21 tons of gutter oil produced every day will be fished away by private individuals. At dinner time, such swill trucks will be parked in front of most restaurants. These swill will be transported to a residential area in the suburbs. Swill and waste oil are mixed in a big pot, and there is a burning flame at the bottom of the pot. The farmer scraped off the floating grease with a big spoon and poured it into another container next to it. The oil extracted by them will be specially purchased, processed and then resold. According to insiders, there are thousands of "oil refining" farmers in Beijing alone. \x1d\ Processing Process of Black Oil \x1d\\x1d\ Near the Old Palace in Daxing District, Beijing, there is a private black oil distribution center that is considered to be the largest in Beijing. There are hundreds of huge oil drums in a 611-square-meter courtyard, which are filled with waste oil and hogwash fat purchased from various places. According to the boss, his family has been doing this business since his grandfather's generation, and it has been more than 31 years now. Just waste oil, he can send out forty or fifty tons a day. His family is the largest number of people doing this business in Beijing. Among those dirty and worn-out oil drums, there is a clear and transparent liquid that looks like edible salad oil, which is a "refined oil" that they "carefully processed" and prepared to sell to the grain and oil market for human consumption. This "refined oil" can't smell any peculiar smell. It is hard to imagine that this clear and odorless liquid actually comes from those dirty sewers. \x1d\ entered the courtyard on the residential road behind the hot pot in Cuizhu Mountain City, Dalian Development Zone, only to see the surrounding weeds and chaos. Several German shepherd dogs in the courtyard kept barking when they saw strangers coming. This is the processing workshop. There, the reporter witnessed the whole process of processing and refining "refined oil". The first step is decolorization. They pour a lot of hogwash fat and waste oil into the filter, and then add a kind of "white clay" to produce a chemical reaction, and the original maroon liquid becomes clear and transparent in a blink of an eye. In this step, according to them, the acid value of oil (acid value is an indicator to measure the quality of oil products, and the lower the acid value, the better the oil) will be greatly reduced. After such "treatment", the oil can easily escape the inspection of the health department; The second step is washing with water. They pour the decolored oil into a large pool, then keep stirring, remove impurities and decolorize it further. The last step is vacuum, that is, put the oil in a vacuum tank and heat it to remove the odor. \x1d\ According to this boss, in his workshop, there are always two sets of such processing equipment, which he has spent several years developing, so it is convenient and easy to use. They keep processing like this every day, and every night someone will come here to pull oil. It has been selling well for more than ten years. \x1d\ Waste cooking oil is processed into a "chain" \x1d\ According to insiders, the processing of "waste cooking oil" has now formed a "one-stop" chain, and many people enjoy it from acquisition to processing to sales. This industry of refining oil from food waste is a profiteering industry. \x1d\ According to a person who collects swill, they can produce 1 barrels (about 181 kilograms) of hogwash fat or waste oil every three days on average, and the average price of each barrel is 581 to 611 yuan. Then, according to this calculation, they can earn 6,111 yuan a month. With such huge profits, how can those unscrupulous traders not "flock"? \x1d\ and for the kind of oil dealer who integrates production and sales, the profit is extremely rich. According to the boss of Daxing District mentioned earlier, the waste oil they bought is 3,411 yuan per ton, and the processed "refined oil" can be sold for 5,111 yuan per ton. After removing various costs, the net profit is about 1111 yuan per ton. \x1d\ It is also known that those who collect oil from oil dealers will blend about 1/3 of salad oil and 1/3 of palm oil into the oil after transporting the oil back, in order to better hide people's eyes and ears and get away with it. In this way, these mixtures are put into small bottles, which will flow to people's tables with those "authentic oils".