Solid household waste is goods and consumer goods (including their fragments) that have lost their original properties and were thrown away by their owner. Along with solid industrial waste, they pose a great threat to the environment and must be recycled.
Household waste not only worsens the environmental situation, but is also a source of additional costs associated with its collection and disposal. As cities grow, these costs increase. To solve problems with MSW in the world, various technologies for their processing have been developed. The most environmentally friendly and technologically advanced solution is the separation of municipal solid waste and their subsequent use as secondary raw materials.
The problem of municipal solid waste
The accumulation of municipal solid waste is a dangerous problem. Pollution of territories with various types of garbage is widespread almost everywhere. A huge amount of it is scattered over the earth's surface in the form of fragments or clusters (dumps). Waste also enters the waters of the Worldocean.
A significant proportion of MSW are products of oil and gas chemistry. They are stable polymeric compounds with a long half-life. The most environmentally harmful of them is polyvinyl chloride (PVC), which is associated with a high content of chlorine in its composition. Construction waste, compared to polymers, poses a significantly lower threat to the environment.
Environmental risks associated with MSW
The impact of municipal solid waste on the biosphere is diverse, large-scale and in almost all cases negative. The options for the impact of MSW on the environment are as follows:
- Contamination of the earth's surface with household waste. Cellophane bags and other types of household waste are an obstacle to plant growth, contributing to a decrease in biological productivity, the rate of soil formation. Household waste in water bodies, oceans and seas can affect the processes of evaporation from the surface of the water.
- Pollution of the environment by the decay products of MSW. This is the most serious of the environmental problems associated with household waste. When polymers break down, toxic compounds are released that poison the soil and groundwater. No less harmful are the products of their combustion. Many landfills constantly smoke, polluting the air, especially in densely populated areas. The most hazardous and MSW-specific combustion product is dioxin, which is released during the combustion of PVC products. It is considered the most toxic chemical compound known to science. Fortunately, volumesthe release of dioxin from combustion is not large enough to cause poisoning, however, its contribution to the overall pollution is quite significant.
In addition to polymer degradation and combustion products, various household chemicals, heavy metals, asbestos from slates, hydrocarbons and many other substances also contribute to the overall pollution. The consequences can be dire:
- Death of animals and fish. Studies have shown that birds and fish can ingest small plastic objects, sometimes resulting in their death as a result of the accumulation of this debris in the digestive system. Animals that feed on landfills are also at risk, because there is a high probability of poisoning.
- Deterioration of the hygienic situation. Garbage heaps often become a breeding ground for pathogens that can be carried to other areas by rodents living there.
- Loss of aesthetic appeal of the area. Being among household garbage is not for everyone. Unsightly appearance, smells, the risk of catching an infection, pollution of water in springs - all this can significantly spoil your outdoor recreation.
- Climate impact. Plastic films and glass block the thermal radiation coming from the earth, causing a local greenhouse effect and an increase in the temperature of the earth's surface. Large accumulations of garbage are a fairly powerful source of methane, which, entering the atmosphere, enhances the greenhouse effect.
- Withdrawal of land. Landfills cause a reduction in free space that could be used forconstruction, creation of squares or parks. This problem is quite relevant, especially near large and medium-sized cities.
Classification of municipal solid waste
There is no unified system for classifying municipal solid waste. Initially, MSW is a single common mass. However, municipal solid waste is a very different chemical composition and physical properties components. The most widespread among MSW are: metal, plastic, glass, wood, paper and cardboard. In many countries, waste classification is the basis for separate disposal and recycling. In Russia, they are still thrown out in one mass and then stored at landfills.
Household waste disposal
MSW disposal involves the use of various methods. The most common methods currently used to dispose of municipal solid waste are:
- Mechanical processing.
- Burial of municipal solid waste at landfills (landfills).
- Waste incineration.
- Complex recycling.
- Use of biotechnology.
Removal of municipal solid waste to landfills is the traditional and most environmentally harmful way to "dispose" of MSW. In our country, he still occupies a leading position.
In order to reduce the volume of waste in landfills, they are often set on fire, which leads to the spread of hazardous substances over large areas and deteriorationair quality. The products emitted during the burning of landfills have a strongly pronounced unpleasant odor and are harmful to he alth. The size of landfills in our country is constantly increasing.
Recycling
At the moment, there are several methods of disposal. The main ways that help to recycle municipal solid waste are:
Mechanical processing is a set of technological operations for grinding, pressing, briquetting. All this leads to compaction and a reduction in the volume of garbage up to 10 times, which makes it more convenient to transport and store it. However, such methods only simplify the problem of disposal, but do not solve it completely
- Integrated waste processing involves the creation of waste sorting and waste processing enterprises. At the first stage, the waste is distributed depending on the type of material (glass, plastic, metal, etc.), and then sent for processing to the appropriate workshops. This method of disposal allows you to get rid of most of the MSW and get secondary raw materials.
- Biological processing methods make it possible to remove from the waste the most accessible for the decomposition of microorganisms organic part, which is converted into the so-called biohumus. For this, a cultured strain of the red California worm is used.
Briquetting
Briquetting should be carried out after the extraction of more valuable components. The remaining debris is mechanicallycompacted and packaged. Formed briquettes are more convenient in storage, transportation and disposal.
Composting
Composting is a biological method of processing, in which solid waste is disposed of by creating so-called compost heaps. Depending on the level of technology development, the period of compost formation is from 2-10 weeks to 1-3 years.
Recycling waste
The best-preserved items are recovered, restored to good condition and reused. This practice also operates in some Russian cities. Glass, iron, aluminum and other metals are melted down and can be reused. Much of the paper waste can also be recycled.
Recycling of plastic from household waste is not carried out in Russia, as it is considered unprofitable. Moreover, our country has large oil and gas deposits, which provide better raw materials.
Solid waste incineration
Incineration of solid waste allows you to get rid of large volumes of garbage, but it also has serious disadvantages. When plastic burns, harmful substances enter the air, the most toxic of which is dioxin.
For this reason, developed countries are now phasing out this method of waste disposal. An additional source of pollution during centralized incineration of MSW is the emission of soot, ash and the formation of unburned fragments, which can account for a third of the initial volume of household waste. All of them have morehigh hazard class than the original MSW, and therefore require more stringent storage and disposal conditions.
In order for waste incineration to bring as many benefits as possible, attempts are being made in Western countries to use it as a source for electricity and heat. This reduces the need for fossil species. An example of such successful cooperation is the waste incineration plant in Vienna. They use modern technologies, thanks to which the burning process becomes safer.
Household waste collection in RF
In Russia, the removal of solid waste from urban areas is regulated by article 13 of the law on "production and consumption waste." Standard metal containers (garbage bins) are used to collect household waste. This practice has been operating since Soviet times.
Usually a trash can is placed in the space between residential buildings. Currently, attempts are being made to organize separate waste collection, which is provided for in accordance with Article 13 of the above law. The division is made into the following categories: plastic packaging, textiles, paper, glass, metal, organic plant waste. However, at the moment, such separation of garbage has not received mass introduction into everyday practice.
Removal of municipal solid waste
For the transportation of solid waste, special vehicles are used - garbage trucks. They differ in the following ways:
- by application: machines used in residential areas and transportation,designed to work with large waste (large-sized waste);
- by body volume;
- by loading method;
- like mechanical debris compaction;
- by the nature of MSW unloading.
The purpose of transportation is the removal of municipal solid waste to landfills. In large cities, garbage disposal is complicated by the long distance that the car must regularly cover.
Collection and temporary storage of waste
In our country, the collection of municipal solid waste is the most costly stage of their disposal. The long distances that a garbage truck has to travel in a large city and the huge amount of garbage generated make it necessary to take measures to rationally plan the collection system. For the same reason, it is necessary to increase the tariff for garbage collection for legal entities. A large amount of additional waste is associated with the operation of commercial outlets, and funds for the removal of such waste are often not enough.
One of the possible solutions is the creation of intermediate storage stations for solid waste, from where bulky waste can be transported to the disposal site using various vehicles, including trains.
Ways to sort household waste
When sorting waste, certain fractions are isolated from the total mass, which can be sent for recycling. To do this, use the following methods:
- Magneticseparation. It is based on the use of powerful magnets that attract ferrous alloys. The recovery factor is about 90% of the total mass of metal in the waste.
- Electrodynamic separation. It is used to remove aluminum, bronze, brass. The recovery rate exceeds 80%.
- Aerodynamic separation is used to remove polymers and paper from the total mass of waste. This method consists in creating a powerful air flow, as a result of which lighter fractions are separated from heavy ones.
- Ballistic separation is based on a sharp change in the speed and direction of the site with waste, which allows you to separate the elastic components from the more viscous. This method can be used to remove glass and some other debris.
Despite the constant improvement of disposal methods, the amount of waste is increasing by 3% every year.
