1, food waste: this is the general term for the residual waste produced by eating various foods. Its main characteristics are fast biodegradation, strong corrosiveness and disgusting pungent smell. The requirement of kitchen waste treatment is not high, mainly to solve the problem of treatment speed.
2. Ordinary garbage: This is the general term for people's daily garbage. Including discarded wood products, paper products, plastics, rubber, textiles, leather products, discarded broken glass and metal products and dust. Ordinary garbage is the main object of urban garbage recycling.
3. harmful waste: Garbage that has instantaneous, short-term or long-term harm to human beings, animals and plants is called harmful waste. Including dry batteries, fluorescent tubes, thermometers and other chemical and biological dangerous goods, flammable and explosive goods, waste containing radioactive substances. Generally, this kind of garbage can't be mixed with ordinary garbage, so it should be removed separately.
For a long time, the main methods of garbage disposal are incineration, landfill and composting. Details are as follows:
content
Sanitary garbage dump
Be lit
compost
operational safety
Ok, pay attention to fire prevention.
okay
okay
engineering reliability
reliable
reliable
Reliable and rich in domestic experience.
Cover an area
big
small
medium
Selected location
Considering the terrain and geological conditions, it is difficult to prevent surface water and groundwater pollution, and it is generally far away from urban areas and has a long transportation distance.
It's easy, it can be close to urban buildings, and the traffic distance is close.
Easy, only need to avoid densely populated areas, the influence radius of odor is less than 200m, and the transportation distance is moderate.
Applicable conditions
Inorganic matter > 60%
Water content; 0.5 tons/day
The low calorific value of garbage is more than 3300kJ/kg without adding auxiliary fuel.
From the point of view of harmlessness, the biodegradable organic matter in garbage is ≥ 10%, and from the point of view of fertilizer efficiency, it should be >: 40%.
Final disposal
not have
Only the residue needs landfill treatment, accounting for 10% of the initial amount.
Non-compost should be buried, accounting for 20~25% of the initial amount.
Product markets
Recoverable biogas for power generation.
Can generate heat energy or electric energy.
It is difficult to establish a stable composting market.
construction investment
reduce
High-ranking, higher-ranking, more important
appropriate
Resource recovery
There are no examples of field separation and recovery, but it is possible.
The pretreatment process can recover some raw materials, but it depends on the proportion of available materials in the garbage.
Tongzuo
content
Sanitary garbage dump
Be lit
compost
surface water pollution
It is possible, but measures can be taken to reduce the possibility.
There is no treatment plant, and the possibility of surface water pollution is less than that of landfill.
It is similar to sanitary landfill in non-composting landfill.
underground water pollution
It is possible that although seepage control measures can be taken, leakage will still occur.
There are no pollutants such as organic matter in the ash, so it is only necessary to take measures such as solidification to prevent pollution when landfill.
Heavy metals may pollute groundwater through compost products.
atmospheric pollution
Yes, but it can be controlled by covering compaction and other measures.
It can be controlled, but measures should be taken to control trace toxic substances such as dioxins.
There is a slight smell, and the pollution index is unlikely.
soil contamination
Only in landfills.
not have
It is necessary to control the content of heavy metals in compost products.
Batteries are widely used in our daily life. Batteries are divided into mercury batteries (button cell), alkaline batteries (ordinary batteries) and manganese batteries (array batteries), which generally contain mercury and manganese harmful to human body to varying degrees, and 95% of the substances in waste batteries can be recycled, especially heavy metals. Therefore, discarding or burning waste batteries will not only cause serious environmental problems, but also waste resources. Ordinary dry batteries are cylindrical, and the outer cylinder is made of zinc, which is the negative electrode of the battery; The carbon rod in the center of the cylinder is the anode; The steel cylinder contains manganese dioxide, chloride hinge and zinc chloride. The following are two ways to recycle materials from waste dry batteries:
1, extracting ammonium chloride
Dissolve the black substance in the battery in water, filter, evaporate part of the filtrate in an evaporating dish to obtain a white solid, then heat, sublimate and collect the purified ammonium chloride.
2, preparing zinc particles
Cut the zinc sheet on the zinc tube into pieces, put it in a crucible, and strongly heat it (the melting point of zinc is 4 19 degrees Celsius). After melting, carefully pour the zinc liquid into cold water to obtain zinc particles. This method can be used to prepare zinc particles in laboratory.
In the past, people always thought that garbage was wasteful and useless, which was a one-sided view. In fact, garbage is a kind of resource, an economical and renewable resource in line with sustainable development, but in the existing treatment methods, landfill can undoubtedly not recycle garbage resources; Incineration is still at a low level of resource recovery; Only comprehensive utilization and management can maximize the recycling of garbage resources. The first step of comprehensive utilization of garbage is classified collection. Classified collection refers to the collection of different types of garbage according to different requirements of garbage disposal or recycling. Classified collection is generally carried out by setting containers of different shapes and colors or specifying specific garbage collectors. This will surely become the main method of garbage collection in the future. According to the experience of some areas, the classified collection of garbage can be based on a residential area. Set up three kinds of trash cans with different colors in the community. One color dustbin contains food waste, one color dustbin contains ordinary waste and another color dustbin contains dangerous waste. Due to the perishable nature of kitchen waste, garbage removal should be more frequent and faster, and it is more suitable to take half a day or a day as a unit; The removal frequency of ordinary garbage and hazardous garbage can be determined according to their respective output, and the output of hazardous garbage is small, so it is recommended to clean it every 2 ~ 4 days. Garbage sorting and transportation to the disposal site can generally be carried out by special departments (or communities with relatively complete conditions). After inspection, these institutions send food waste, ordinary waste and hazardous waste to different treatment sites for final treatment. Among them, kitchen waste can be treated by fermentation and other methods to produce gas and fertilizer. In ordinary garbage, paper and wood are renewable paper products; Glass and metal can be melted to make new products; Plastics and rubber can also be melted and put into reproduction. In addition, 1 ton waste glass can produce 20,000 beer bottles or window glass equivalent to the area of a basketball court after being treated by mechanized technology; After recycling, waste plastics can be turned into crude oil, from which diesel and gasoline can be extracted. About 65% ~ 70% of the total municipal solid waste can be eaten by biochemical technology and special machines. Using the principle of microbial fermentation, garbage can be turned into granular or powdery fertilizer or feed within 24 hours, which can be used for public green space or flower cultivation in citizens' families. Hazardous waste is specially treated to remove its toxicity. This is the development of comprehensive utilization of garbage disposal methods.
Through this study and research, we not only understand the treatment and utilization of domestic garbage, but also accurately treat the garbage made by individuals, so as to turn garbage into treasure as much as possible. We must firmly believe that one day, we will walk out of the "besieged city" of garbage.
Attachment 1:
Campus garbage disposal should implement a classified recycling system, and the specific operation methods are as follows:
(1) Each class will set up a small garbage dump in the class, and the garbage will be classified according to paper, plastic and metal (such as cans). ), batteries, and other five categories of classified collections. Because there is a lot of paper and plastic, it can be cleaned once a day. In addition, considering the harm of batteries to the environment, students are advised to recycle waste batteries in a unified way.
② The school has set up several large trash cans to recycle the garbage of each class, and set up more small trash cans on campus. The school is responsible for contacting the social recycling unit and sending out the recycled garbage in time.
(3) Schools should establish a grading system to encourage classes with good garbage collection. The recovered income can also be returned to each class for use.
Attachment 2:
Students' suggestions on campus white garbage disposal;
(1) Schools should educate students to enhance their awareness of environmental protection and publicize the dangers of white pollution.
(2) Students should not throw rubbish at will, and tell people who throw rubbish everywhere the importance of environmental protection.
(3) The school will classify, recycle and centrally treat the garbage.
(4) Add trash cans and put them in places with serious white pollution (such as the entrance of a canteen).
(5) Design an environmental protection sign and hang it in an eye-catching place.
(6) Try to reduce the use of plastic bags to package items, and put an end to the use of disposable foamed lunch boxes (disposable lunch boxes used in school canteens are prohibited by the state, but they are still in use).
(7) Call on the whole society to enhance environmental awareness.
(8) Schools should not burn garbage.