This project belongs to the fields of organic solid waste (straw, livestock and poultry manure, kitchen waste treatment) and circular economy.
In recent years, organic waste such as kitchen waste, livestock and poultry manure, and straw from agricultural production have become major sources of pollution that threaten my country's environmental security. Illegal use of kitchen waste to raise pigs and burn straw has been repeatedly prohibited. It not only wastes resources, affects the safety of the food chain, pollutes the environment, but also poses a fire hazard and seriously threatens transportation safety. Smoke produced by straw burning is very harmful to the environment. Data show that straw incineration will cause rapid air pollution in a short period of time, and the three pollution indices of sulfur dioxide, nitrogen dioxide and inhalable particulate matter in the atmosphere will reach high peaks. The concentration of sulfur dioxide is twice higher than usual, and the concentration of nitrogen dioxide is three times higher than usual. The proportion of inhalable particulate matter PM2.5 in PM10 reaches more than 90%, seriously affecting people's health.
Secondly, organic solid waste such as kitchen waste, livestock and poultry manure, and straw has become one of the sources of pollution to the human living environment with the development of catering and the rapid development of intensive livestock and poultry farms, and has attracted close attention from people. The amount of kitchen waste, livestock and poultry manure, and straw produced in my country is six times that of industrial solid waste. Among them, kitchen waste and livestock and poultry manure contain a large amount of organic pollutants. If it is landfilled without treatment, it will directly enter the water body, which will aggravate the eutrophication of rivers, causing environmental problems such as stench, which will cause serious environmental pollution and environmental remediation pressure.
In view of this, it is very important to scientifically deal with organic waste resources.
At present, the main treatment of kitchen waste at home and abroad is landfill and incineration; the main method for treating straw and livestock and poultry manure is high-temperature composting and fermentation, and the burning problem of rural straw cannot be contained; but there is not much research on technical and economic feasibility. Kitchen waste and livestock and poultry manure contain a large number of pathogenic bacteria, such as Escherichia coli, Salmonella, and Escherichia coli, and pathogenic microorganisms can easily reproduce in large numbers and rapidly. If not handled properly, the pathogenic bacteria are very likely to survive in organic fertilizers, causing secondary pollution to the soil and water environment and causing the spread of diseases.
Returning crop straw to the field has high requirements on operating mechanical performance and high operating costs. Not deep plowing after returning straw to the field is unfavorable to the growth of the next crop. For the above reasons, the utilization of straw resources has been in the exploratory stage.
This project adopts internationally advanced subcritical hydrolysis technology as a technical solution, and has researched and invented the industrial equipment technology of "Subcritical Water Treatment of Urban and Rural Organic Solid Waste and Production Organic Fertilizer and Equipment (referred to as HPS Technology)" as a means to carry out resource research and production of organic fertilizers based on straw, kitchen waste, livestock and poultry manure, combined with the tail product of crop straw treated by HPS technology, can achieve zero pollution, zero emission, resource and harmlessness of waste and wastewater. Efficient, economical, green and environmentally friendly, in line with Shanghai and the country's policies and guidance. It is characterized in that the critical temperature of water TC=374.2℃ and the critical pressure is PC=22.1MPa. When the temperature and pressure of the system exceed the critical point, it is called supercritical water (SCW). When the temperature of the system is between 150 and 370℃ and the pressure is between 0.4 and 22.1MPa, it is called near-critical water (NCW). Subcritical hydrolysis reactions utilize water in a high temperature and high pressure environment. According to the principle of subcritical hydrolysis reactions, molecules of organic matter such as starch and protein can be quickly decomposed into small molecule nutrients such as glucose and amino acids that can be quickly absorbed by animals and plants; in addition, subcritical water can also decompose environmental pollutants and make them harmless. Since the subcritical hydrolysis reaction does not rely on chemicals such as organic solvents, but uses water as a solvent, it can be said to be mild and safe to the environment.