Environmental impact analysis of different treatment methods for food waste

Food waste mainly refers to some food residues and processing waste generated during food processing and eating activities. Its components mainly include rice and flour food residues, vegetables, animal and vegetable oils, meat and bone, etc. They are household waste generated by residents in the process of daily consumption, characterized by extremely easy decay and deterioration, malodorous odor, and easy transmission of bacteria and viruses. With the continuous development of the catering industry, kitchen waste has accounted for a large proportion of domestic waste. In 2020, the output of domestic waste in large and medium-sized cities in China was 2.35 × 108 tons and is still growing at a rate of 8% to 10% per year. Among them, food waste accounts for about 30% of the total urban domestic waste. Food waste has a dual impact due to its high water content, salt content, organic matter content, and trace element content. They are polluting and harmful, but also have high utilization value.
At present, although garbage treatment stations of a certain scale have been built in various regions, the capacity of treatment still cannot meet the actual demand for garbage treatment, and the absorption capacity of food and kitchen waste in various regions still needs to be continuously improved. There are many ways to deal with kitchen waste, such as sanitary landfill, incineration and composting technology. The method of sanitary landfilling mainly refers to filling garbage into low-lying areas and treating garbage by paving and compacting. Compared to the other two treatment methods, this treatment method and technology is the simplest and mature, with relatively low investment and operating costs, and is suitable for the treatment of all kitchen waste. Incineration refers to the pretreatment of food waste followed by furnace heat treatment, in which pathogens such as viruses, bacteria, parasitic eggs, etc. are completely eliminated. After incineration, the heat generated can also be converted into thermal energy for power generation. The third is composting technology, which utilizes the decomposition action of microorganisms in nature, through continuous aerobic fermentation in a closed fermentation tank for about 7 days, and processes organic solid waste into bio-organic fertilizer that can be used for crops after microbial fermentation, deodorization, and ripening. This method is not only suitable for poultry manure such as chicken manure, cow manure, pig manure, sheep manure, but also suitable for the treatment of kitchen waste, with low investment and simple process.
The three different treatment methods can also cause varying degrees of negative harm. Sanitary landfilling first creates an impermeable layer between waste and soil, which does not ensure the isolation of harmful substances in waste from the soil. It is still possible to infiltrate harmful substances into soil and groundwater, causing pollution. Secondly, this landfill method will occupy a large amount of land and is not suitable for long-term use. Finally, landfill waste may produce harmful gases that threaten the environment and people's health. The incineration method can generate a large amount of harmful gases, such as hydrogen sulfide, sulfur dioxide, chlorinated dibenzo dioxins, chlorinated dibenzo furan, and other toxic gases, which pose a threat to the ecological environment and people's health. The third composting technology is currently the most perfect way to treat food and kitchen waste, neither generating harmful gases nor harming people's health. The decomposition and fermentation of organic manure fermentation tanks will produce a large amount of organic manure, which is suitable for agricultural use. However, this method also has certain drawbacks, namely, chemical substances such as plastic and glass bottles in kitchen waste cannot be effectively decomposed.
Today, with the rapid development of science and technology, we should seek more efficient treatment methods that are compatible with the social environment and economic benefits. The general public, government departments, and enterprises should take a long-term development perspective to demand more suitable food and kitchen waste treatment models. Currently, high-temperature aerobic fermentation tank is a good choice