The classification of garbage refers to the division of garbage into a number of categories with different attributes according to their different components, attributes, utilization value and impact on the environment, and according to the requirements of different disposal methods.
Domestic waste can be divided into four categories: recyclable waste, food waste, hazardous waste and other waste. Currently, the main methods of waste disposal are comprehensive utilization, sanitary landfill, incineration and composting.
Recyclable waste includes paper, metal, plastic, glass, etc. Recycling through comprehensive treatment can reduce pollution and save resources. Such as each recycled 1 ton of waste paper can make good paper 850 kilograms, saving 300 kilograms of wood, than the same amount of production to reduce pollution by 74%; each recycled 1 ton of plastic beverage bottles can be obtained 0.7 tons of secondary raw materials; each recycled 1 ton of scrap iron and steel can be refined 0.9 tons of steel, smelted with ore to save 47% of the cost of reducing air pollution by 75%, reducing 97% of the water pollution and solid waste.
Kitchen waste, including leftovers, bones, vegetable roots and leaves and other food waste, composted by biotechnology in situ treatment, each ton can produce 0.3 tons of organic fertilizer.
Hazardous waste includes waste batteries, waste fluorescent tubes, waste silver thermometers, expired medicines, etc., which require special safe treatment.
Other garbage includes masonry ceramics, slag, toilet paper and other waste that is difficult to recycle in addition to the above categories of garbage, and the adoption of sanitary landfill can effectively reduce the pollution of groundwater, surface water, soil and air.
Medical waste classification.
After the use of disposable medical devices, whether or not to cut the needle, whether or not contaminated by the patient's body fluids, blood, excreta, are medical waste, should be managed as medical waste.
After the use of a variety of glass (disposable plastic) infusion bottles (bags), not contaminated by the patient's blood, body fluids, excreta, does not belong to the medical waste, do not have to be managed in accordance with the management of medical waste, but this type of waste recycling can not be used for the original purpose for other purposes should be in line with the principle of not endangering human health.
1. Landfill treatment
Landfill is a large number of effective ways to eliminate municipal waste, but also all the waste treatment process residuals of the final treatment method, at present, China is generally used in direct landfill method.
The so-called direct landfill method is to fill the garbage into the pit that has been prepared to cover the compaction, so that it undergoes biological, physical and chemical changes, decomposition of organic matter, to achieve the purpose of reduction and harmlessness.
2. Incineration
The incineration method is to put the garbage in a high-temperature furnace, so that the combustible components are fully oxidized in a method that produces heat for power generation and heating. The waste-to-energy system jointly developed by Westinghouse and O'Connor has been successful. The system's incinerator in the combustion of garbage can be up to 7% humidity of the garbage into a dry solid for incineration, incineration efficiency of more than 95%, at the same time, the incinerator surface of the high temperature of the heat can be converted into steam, which can be used for heating, air-conditioning equipment and steam turbine power generation, etc.
3. Composting
To pile up the garbage into a pile of domestic garbage, heat preservation to 70 ° C for storage, fermentation, the microbial decomposition ability of the garbage. With the ability of microbial decomposition in the garbage, the organic matter is decomposed into inorganic nutrients. After composting, the household garbage becomes hygienic and odorless humus. Both the solution to the garbage outlet, but also to achieve the purpose of re-resourcing, but the amount of domestic waste compost, low nutrient content, long-term use of easy to cause soil compaction and groundwater quality deterioration, so the scale of compost is not easy to be too large.