Kitchen waste is a kind of domestic waste formed in the process of living consumption, mainly from restaurants, canteens, street snack shops and other places.Because its transportation is not convenient, and as a waste filling is easy to breed flies, resulting in serious environmental pollution, therefore, the scientific treatment of food waste has become the fundamental way of urban management and construction.The followings are current main processing way about kitchen waste.
1.Pulverization and direct discharge
Crushing and direct discharge treatment is the main method for European and American countries to deal with a small amount of scattered kitchen waste, which is directly broken and crushed at the point of occurrence of kitchen waste, and then used hydraulic erosion to discharge it into the municipal sewage network of the city, which is combined with urban sewage into the urban sewage treatment plant for centralized treatment. Crushing method for the treatment of a small amount of scattered food waste such as household kitchen waste, have the advantage such as cheap, technology handy, can reduce the moisture content of city rubbish, reduce collect quantity, To improve the heat output of municipal solid waste.
Landfill is the main way of harmless disposal of domestic waste in most countries. As kitchen waste contains a large number of biodegradable components, the stability time is short, which is conducive to the restoration and use of the landfill site, and the operation is simple, so it is widely used. As the understanding of the exploitability of kitchen waste is more and more extensive, no matter in Europe and America, Japan or China, the landfill rate of kitchen waste is showing a declining trend, and even many countries have banned kitchen waste into the landfill.
The fertilizer treatment methods of kitchen waste mainly include aerobic compost and anaerobic digestion. Aerobic composting is a process in which organic solids are decomposed into soluble organic substances by extracellular enzymes secreted by aerobic microorganisms under aerobic conditions, and then infiltrated into cells to realize the whole composting process through microbial metabolism. At the same time, by the aerobic composting lead some similar methods, such as worm compost is a new technology developed in recent years, the use of earthworms swallowed a large number of kitchen waste, and mixed with soil, through the role of the mechanical polishing gizzard and intestinal biological chemistry itself or other organic matter can be converted to biological nutrients are available. The anaerobic digestion treatment of kitchen waste refers to the decomposition of organic waste by microorganisms under specific anaerobic conditions, in which carbon, hydrogen and oxygen are converted into methane and carbon dioxide, and elements such as nitrogen, phosphorus and potassium are retained in the residue and converted into a form that can be easily absorbed and utilized by passive plants.
Current feed market potential is huge. As a result of kitchen waste as raw materials, the price is low, the supply is huge, the product is rich in nutrition, the profit range is large, with strong market competitiveness.There are two ways to feed :(1) biological treatment of feed. The principle is to add the cultivated bacteria into the sealed storage of kitchen waste, and the bacteria will be propagated and killed to make the feed. (2) high temperature disinfection feed. The principle is to use high temperature disinfection, kill the virus, after grinding into feed, can be used for livestock. The more mature feed processing method of kitchen waste is the comprehensive utilization of pelleting technology, extrusion and drying technology. The concentration of bacteria in the extruded feed was much lower than that in other samples. Due to the rising temperature during extrusion, a single screw dry extrusion process can greatly reduce the concentration of potential pathogens. At present, some manufacturers have developed supporting technical equipment and put it into operation.
Energy treatment of kitchen waste is in rapid arisen in last few years,it mainly includes incineration, thermal decomposition and fermentation to produce hydrogen.Incineration method and treatment of kitchen waste has high efficiency, and ultimately resulting residue is about 5% which is easy to be disposed, incineration is done in a special incinerator, the heat energy can be converted to steam or electricity, so as to realize the recycling of energy, but the moisture content of eat hutch garbage is high, low calorific value, burning need to add the auxiliary fuel, resulting in the problem of large investment, and tail gas treatment is also a problem. Pyrolysis is the process of pyrolysis of waste at high temperature, which converts the energy contained in waste into gas, oil and carbon and then USES them. Pyrolysis has broad application prospects, but the technology has not reached the practical stage and is rarely used at present. As a kind of high quality clean energy, hydrogen is widely considered as the most potential alternative energy, and many scholars have done research on it. More and more attention will be paid to the energy treatment of kitchen waste.