According to different sources, kitchen waste is mainly divided into catering waste and kitchen waste. The former is produced by leftovers in restaurants and canteens, and has the characteristics of large quantity, relatively concentrated quantity and wide distribution. The latter mainly refers to the leftovers discarded by residents in their daily cooking, which come from thousands of households, with a huge amount but relatively scattered, and the overall output exceeds that of food waste.
One minute it's delicious food, and the next minute it's garbage. Due to food culture and eating habits, kitchen waste has become a unique phenomenon in China. The table garbage in China is amazing, and a huge amount of kitchen garbage is produced every day. According to the statistics of relevant departments, the daily kitchen waste (including waste cooking oil) is about1800-2,200 tons, which fluctuates with different seasons. The proportion of kitchen waste in the physical group of domestic waste is generally about 50%. According to the terminal treatment capacity of domestic waste in 20 15 years10.8 million tons, if all kitchen waste can be effectively separated from dry and wet, the theoretical output of kitchen waste will reach 0.9 million tons. Therefore, in order to classify domestic waste, it is very important to classify kitchen waste. Therefore, it is particularly important to separate the dry and wet parts of households (that is, other garbage with low moisture content and kitchen waste with high moisture content).
Types of kitchen waste:
waste sorting
First, the garbage formed in the process of food processing, mainly the stems and leaves cut by vegetables, soil entrained by vegetables, fish scales, head and foot feathers of poultry, etc. The rest is handled by the kitchen. This kind of garbage does not contain leftovers and grease trap garbage, so it contains less oil and has low economic value. Generally, no one collects this garbage alone, and this garbage is mostly used for composting to produce organic fertilizer.
Second, leftovers, commonly known as swill. This kind of garbage is mainly leftover food and soup, and the oil extracted from it is called swill oil. This kind of oil is basically neutral in nature, and its acid value is not high, so it is easy to enter edible oil. This kind of pig that grew up eating swill is called garbage pig.
The third is grease trap garbage. This kind of garbage is mainly a small amount of food, some grease and detergent left on the tableware in the washing process of restaurants and restaurants. With the washing water entering the grease trap, grease substances float on the water surface, forming grease trap garbage. The grease content of garbage in grease trap is relatively high, generally 20%-80%. With the different hotel grades, the oil content varies greatly. The oil extracted from the grease trap is called "gutter oil", which has high freezing point and high acid value.
Hazards of unclassified kitchen waste;
Because kitchen waste is easy to rot and deteriorate, it will produce unacceptable bad feelings, such as irritating smell. However, the kitchen waste produced by catering industry contains a lot of leftover soup and spoiled water, which is easy to leak during collection and transportation and affects the urban environment. Direct landfill treatment of kitchen waste will cause serious pollution to groundwater.
According to the estimation of experts from the Ministry of Agriculture, kitchen waste contains a lot of nutrients, and the main components are oil and protein. It can be processed into high-energy protein feed instead of corn, fish meal and soybean meal, and is also a suitable raw material for producing biodiesel.
Experts explained that according to the dry matter content, 50 million tons of kitchen waste is equivalent to 5 million tons of high-quality feed, and the energy contained is equivalent to the energy output of 6.5438 million mu of cultivated land every year, and the protein contained is equivalent to the protein output of 20 million mu of soybeans every year. In other words, if all the kitchen waste produced in China in one year is used, it is equivalent to saving about 6.5438+million mu of cultivated land.