Due to the fact that the country's population is growing, the demand for consumer resources is also increasing. And as a result, an increase in resource consumption also increases the amount of household waste.
Garbage dumps annually expand and occupy an increasing area, water bodies are polluted due to wastewater, which carries a lot of infections and dangerous elements for nature. Therefore, recycling household waste, in our time, it should be developed no less than industry, so that the resulting MSW (waste) cannot accumulate and pollute the soil, atmosphere and water.
It is quite a logical fact that without the timely introduction of innovative technologies for recycling waste, the planet will soon turn into a huge dump and become unsuitable for the existence of not only people, but all living beings.
To avoid such a result, scientists in many countries have long been looking for the best ways to deal with waste, thanks to which it would be possible to destroy or recycle solid waste without harm to environment, as well as rid the territorial space of huge volumes of garbage.
To date, the disposal of municipal solid waste is carried out by the following well-known methods that allow you to get rid of garbage:
- Burial or temporary storage of waste at special landfills. Here sorting and unsuitable materials are carried out, covered with earth.
- Composting. Natural decomposition of biological substances, their processing into mineral fertilizers for soil and planting crops.
- Thermal treatment of MSW. This method allows you to burn almost any type of waste, which minimizes their volume as much as possible, and also provides an economic benefit in the form of thermal energy.
- Low and high temperature pyrolysis.
Methods of disposal of solid waste
MSW landfill
Disposal of solid waste by landfill is one of the most common ways today to get rid of garbage. But this method is common only among non-combustible waste, as well as among such substances that can release toxic elements during combustion.
The landfill for solid waste disposal is an unusual landfill, it is equipped with all modern engineering facilities that allow the systems for combating and groundwater to isolate all harmful substances. This also applies to the atmosphere, that is, there are practically no leaks of any chemical and toxic elements, which is main goal, to ensure the safety of the country's ecology.
But there are also disadvantages in such methods, for example, the formation of gas during the decay of garbage. Some are equipped special equipment, for pumping out gas, which, as it should be noted, is subsequently used to generate electricity. And it allows almost autonomous operation of equipment located at landfills. But unfortunately, so far, in Russia, only a small part of all such landfills are equipped with such equipment, while all other waste sites do not have the ability to deal with gas emissions.
But even taking into account the presence of such installations, the ecology remains not protected from the effect of the decomposition of garbage in the soil, and all the secretions in the process of decay and fermentation. Since the buried material will completely disappear only after tens or even hundreds of years. Therefore, despite the relative cheapness of this method of dealing with waste, for the environment, the best option is to completely get rid of garbage, by processing it and using it in the manufacture of any product. In this case, the risk of environmental pollution will be minimized.
MSW composting
Disposal of household waste through composting is a technology that allows, therefore, MSW through natural biological decomposition. The main source of composting is organic substances and materials, this method is applied to them very actively. Composting provides not only the opportunity to get rid of bulk substances that pollute the environment, but also supplies agriculture with fertilizers that are useful for the soil, allowing you to normalize the balance of minerals in the earth and grow various vegetables and crops.
But since this method does not allow the processing of most types of waste, requires a careful sorting process and takes quite a long time, it has not gained popularity in the country and is not developed at the proper level. There is not one in Russia industrial enterprise, which carried out composting in such volumes and made it possible to clean at least one city from organic waste.
- in small farms;
- in garden plots;
- in private houses;
- in agricultural organizations;
- on livestock farms, etc.
However, this method does not require large expenses, although it does not cover all types and classes of waste material, but it allows you to fully get rid of a huge part of the waste produced by the country, which occupies a third of all waste in the country. Establish a centralized process and carry out composting at special sites equipped with all the necessary buildings and structures. To build original plants, for starters, in large cities of the country, for the processing of solid waste and other organic waste. The end product, compost, will be very useful in many ways. agriculture, and, most importantly, its cost will reduce the cost of growing many crops and provide funds for the operation of such plants.
Thermal processing of MSW
With the help of heat treatment, the disposal of household waste allows you to get rid of organic fractions, this method is quite often used in large-scale waste generation. Thermal, represents several processes that together make it possible to get rid of any non-toxic type of waste material or to minimize them as much as possible in volume and mass. Also, heat treatment is carried out to neutralize devices, equipment and other things infected with infectious or epidemiological bacteria that may have the following origin:
- medical institutions;
- laboratories;
- veterinary clinics;
- chemical enterprises;
- oil refining industry;
which in the future, having received an inert state, can be buried in special landfills or placed in temporary storage for further processing and recycling as a raw material.
Important advantages of heat treatment or recycling are modern methods allowing you to get:
- effective decontamination or neutralization of any waste material;
- complete destruction of any microflora and even pathogenic;
- reduction of scrap in volume up to 10 times;
- use the energy potential of organic waste.
Incineration has many advantages over other methods, it is worth highlighting the main ones, these are:
- high level of testing technologies;
- stably produced equipment and long service life;
- high-tech process is automated;
but the main thing is that Lately, factories or organizations involved in waste incineration receive thermal energy or electricity that can be used for autonomous operation of the enterprise. In some cases, the surplus of such energy is diverted to urban stations, which ultimately allows entire areas to be supplied with electricity or heat them.
Plasma processing of MSW
Not as developed as the above methods and ways of getting rid of scrap, but a very promising technological process that allows you to solve everything ecological problems, utilize and ultimately provide energy that is useful and necessary for society.
The plasma processing technology uses a melting point much higher than any slag melting furnace. Thus, the output is a vitrified product, absolutely harmless and, most importantly, does not require further costs for neutralization or special disposal.
Plasma processing is a waste gasification technology, the scheme of this method makes it possible to obtain gas from the biological components of waste. The resulting gas is then used to generate electricity or steam. The main material for plasma processing is MSW in the form of slag or neutralized residues.
The main advantage of high-temperature pyrolysis is the ability to get rid of waste in an environmentally friendly way, at no extra cost:
- for preliminary preparation;
- for sorting;
- for drying, etc.
These qualities allow thermal processing to be rightfully considered the most environmentally and economically beneficial technology for the disposal of solid waste.
All these methods are designed to solve.
Also watch the video - how the waste recycling plant works
The current system for handling them in our country was formed back in Soviet times. The main method by which the disposal of municipal solid waste is currently taking place is landfill. At first glance, it is the cheapest, but in the calculations it is very often forgotten to take into account that, in addition to the costs of maintaining the site, the costs of decommissioning, compensation for damage to nature and irretrievable loss of resources are necessary.
Alternatively, in some metropolitan areas, recycling solid waste occurs by burning them on specialized ones. However, this method has a number of disadvantages, one of which is that the incinerator is also a source of the surrounding area. True, to be fair, it should be noted that there are combustion technologies that minimize the formation of dioxins. In addition, as a result of this method, the amount of waste is reduced tenfold and it is possible to produce heat or electricity, and the resulting slag to be recycled to industry.
Also disposed of through aerobic biothermal composting. Before that, they are sorted. Everything that is formed as a result of consumption can be divided into three main groups. The first is (MSW), which can be processed into useful materials and receive a certain income through their sale, which allows compensating for costs. The second is biodegradable waste, they can be turned into compost, however, the costs associated with this are difficult to compensate. The third is non-recyclable MSW, the disposal of solid waste of this group is carried out in various ways, depending on their specific composition.
Aerobic biothermal composting is currently considered the most promising technology. With the help of it, solid waste is transferred to a harmless state and becomes compost, which is a fertilizer that contains trace elements, phosphorus, nitrogen, and potassium. Such disposal of solid waste allows you to return them back to natural in nature.
The use of mass processing of MSW using the latter method is difficult today for a number of reasons: the imperfection of legislation, the lack of a unified information base for all types of MSW, poor control over compliance with regulations, insufficient funding. If we turn to experience developed countries, then it becomes clear that it is possible to set up properly only if you approach this issue systematically. All processes related to garbage disposal should be set up and debugged. It is necessary to cover everything in a complex, including sources of waste generation (organizations and people), transportation, storage, sorting, processing, final disposal. The public and each individual citizen should be actively involved in solving this problem. And most importantly, we need an effective mechanism for economic stimulation of a rational and careful attitude to what nature has given us.
Waste disposal - here, perhaps, the main problem modern humanity. Every day we produce so much garbage that would be enough for the whole city of the past.
The ecological situation is so acute that scientists are literally screaming about the need to take control of this sphere of human life.
Unfortunately, the current methods of waste disposal are often inefficient and do not result in the expected effect - the cleanliness of the environment.
Nevertheless, according to experts, improvements in this area are observed. At the same time, today, ordinary people are beginning to comprehend the need for sorting and recycling waste so that in the future their descendants do not drown in garbage.
Residents of civilized European countries are accustomed from childhood to sort and throw away garbage exclusively in the places designated for this.
A significant plus of this behavior is the regular processing and recycling of garbage that has already been in use once.
Unfortunately, in our country, such benefits of civilization are just emerging. Waste sorting and its further processing is rather an exception to the rule than the norm.
If you live in a suburban village and it is customary for you to sort your garbage by type and throw it into separate bins, you are a happy person.
You can also organize the recycling of existing garbage with your own hands by putting into use several garbage cans for waste of a different nature.
By organizing the removal of food waste and other garbage, you are helping to prevent an environmental disaster that has been looming for a long time.
Try to start small. On average, one house in a medium-budget cottage village produces a large bag of garbage per day.
All garbage ends up in a landfill, where, at best, it is recycled, and at worst, it is left for further independent decomposition.
Waste disposal methods today
There are several ways to dispose of waste, which are successfully used in Russia.
- Waste disposal.
- Garbage burning.
- Composting.
- Low and high temperature pyrolysis.
Around each of the listed methods there are disputes about its effectiveness, efficiency and speed of work.
The oldest method of getting rid of household and food waste is its burial. It is also the most dangerous and ineffective.
Even food waste buried in a quarry or pit can accumulate a huge amount of decomposition and decay products, which can cause groundwater or air poisoning.
What can we say about solid waste, the disposal of which in other ways leads to the release of toxic gases into the atmosphere. Special landfills are equipped for the disposal of hazardous waste.
They, as people believe, are able to protect against the release of toxic substances into the soil, water and air that can poison all living things within a radius of several kilometers.
However, time proves the inefficiency of this method of disposal and even its danger.
Another recycling method that is not widely used in our country is composting. It is found in private households when disposing of food waste, but is much less commonly used in mass waste processing.
However, composting is effective method processing, resulting in compost that can be used in agriculture.
Compost can be created both from purely food waste and from a stream of unseparated garbage. If you do this processing centrally, you can get good results.
If we talk about the effective reduction of waste, then heat treatment shows itself most effectively. It allows you to neutralize most waste, while reducing their volume at times.
Modern disposal by incineration also involves the use of combustion energy. This trend is spreading more and more, giving new opportunities in the future.
Waste incineration in order to obtain heat and electricity is a method that can turn landfills into an energy source for the operation of central heating systems and various industries.
One step up this method Plasma processing of garbage is worth it - a phenomenon in our country is so rare that it is hard to believe in it.
Plasma recycling is the disposal of waste, which results in gas from organic compounds and slag from solid waste.
When processed in this way, energy can be used for peaceful purposes, which is what happens in more developed countries in this regard.
If the disposal of your own waste is important to you, try to find an organization in your area that sorts and recycles waste.
In this case, the most that is required of you is to independently sort the waste into separate containers and order the waste collection regularly.
Disposal and recycling of household waste is an urgent problem modern world. There are more and more landfills on earth, extensive littering threatens environmental catastrophe. The solution to the problem is the processing of solid waste at specialized waste processing plants. Following the conditions of objective reality, humanity needs to improve the methods of waste disposal in order to achieve the most efficient processing of solid waste at minimal cost.
3 Reasons Why Good Solid Waste Recycling Is Necessary
Waste can be divided into the following kinds:
- Household waste. This group includes human waste. The garbage that is thrown out of residential buildings and office buildings. Plastic products, food leftovers, paper, glass and other items. Many wastes are assigned to IV and V hazard classes.
The issue of plastic waste should be resolved as follows: the garbage is subject to mechanical grinding, followed by chemical treatment with solutions, as a result of such manipulations, a mass is formed from which polymer products can be made again. Paper and food leftovers can turn into compost, rot and benefit the agricultural sector of the economy.
- biological waste. This type of waste is produced by biological species (humans and animals). A large number of such materials are produced by veterinary clinics, hospitals, sanitary and hygienic organizations, catering enterprises and other similar institutions. Biological waste is destroyed by incineration. All materials of organic origin can be disposed of in this way.
- Industrial waste. Such wastes are the result of manufacturing processes. Construction, operation of industrial equipment, installation and finishing works - all this leaves behind a huge amount of wood, paints and varnishes, heat-insulating materials, some of which can also be burned. For example, wood releases energy during combustion, which can also be used for social purposes.
- radioactive waste. It is not uncommon for biomaterials and other wastes to contain radioactive substances that pose a hazard. This group also includes gases and solutions - that is, those wastes that cannot be used in the future. Some of this garbage can be destroyed by burning, but the rest can only be buried.
- Medical waste. This is the garbage of medical institutions, 80% of which is non-hazardous household waste, and the remaining 20% poses a risk to the human body. Like the processing of radioactive waste, the destruction of this type of waste has many restrictions and prohibitions in Russian legislation. The methods of its burning and burial are described in detail. For medical waste, as well as for radioactive waste, special burial grounds are created. Some destroy medical waste like this: they put them in bags and burn them. But many drugs belong to hazard classes I and II, so this disposal method is clearly not for them.
All wastes are classified according to the degree of their danger to the environment. There are four hazard classes in total. The first class is garbage, which poses the most serious threat to the planet and all organisms living on it. If you do not process first class MSW in the manner prescribed by law, the damage to the ecological system may be irreparable. Waste of the first hazard class: mercury, lead salts, plutonium, polonium, etc.
Waste of the second hazard class can also greatly harm the environment. The consequences of such damage will continue to impact for a long time. The planet will recover within 30 years of being polluted by such waste. These include arsenic, selenium, chlorine, phosphates, etc.
After waste of the third class of danger, the ecosystem is able to recover in a decade. Of course, recovery is possible only after the processing of MSW, otherwise the waste will not stop harming the environment. The third class includes zinc, ethyl alcohol, chromium, etc.
The fourth hazard class is low-hazard waste (simazine, sulfates, chlorides). After they are removed from the infected object, the ecosystem needs to recover for three years.
But waste of the fifth class is completely safe.
Consider, why is it necessary correct processing of solid waste:
- Waste pollutes the environment, which is already oversaturated with emissions from factories and vehicle emissions.
- Resources that are extracted from nature or created industrially are seriously limited, so it is advisable to recycle and reuse them.
- It turns out to be cheaper to use recycled raw materials, so the processing of MSW is economically beneficial.
The most common methods of processing MSW
Method 1Waste disposal.
Landfills are created specifically in order to carry out the processing of solid waste on their territory. The flow of garbage enters these areas (up to 95%), and then the organic part decomposes spontaneously. In the polygon zone are formed special conditions for intensive biochemical process of dissociation. The resulting anaerobic environment promotes recycling enhanced by methanogenic microorganisms that form biogas (otherwise called "landfill gas"). What is the disadvantage of such polygons? Landfill gas toxins enter the atmospheric air and spread in the direction of the wind over long distances. And if they are mixed with industrial emissions, then the environment is even more dangerous.
Given the accumulation of microorganisms that enhance the flow of chemical reactions, local fires can occur due to excessive overheating. At the same time, polyaromatic hydrocarbons are released into the environment, causing oncological diseases. Such emissions are thousands of times higher than the permissible concentrations of such substances in the air. Aqueous solutions formed in the air fall out in the form of precipitation, during the evaporation of which, as in the combustion of polymeric substances, dioxins are released. So, through precipitation, harmful chemical elements enter the ground and surface waters.
Since it is impossible to arrange such landfills within the city, plots outside large settlements are allocated for them. If we calculate the cost of allocating territories, their arrangement in accordance with all the rules, transportation costs for transporting garbage to such a landfill for processing solid waste, we get a rather impressive figure. Add to this the air pollution associated with the release of combustion products of motor fuel, the deterioration of suburban roads. The picture is not rosy.
Due to the fact that the qualified arrangement of landfills for the processing of solid waste is associated with high costs, some people prefer to organize unauthorized dumps. In such places of unauthorized storage, there is no sealing, liquid waste directly enters the environment without passing through the neutralization stage, creating a high danger to the population. And these dumps only multiply and grow.
Thus, it is very dangerous to store unrecycled waste at landfills, and therefore this method of disposal should be prohibited at the legislative level. And there are many reasons for this:
- lack of bacteriological and epidemiological safety;
- rapid spread of dangerous human body substances over large areas (penetration into air, water, soil);
- release of dioxins during fire;
- the high cost of land and landfill facilities, as well as the need for subsequent reclamation of the site;
- contradiction to the Fundamentals of State Policy in the Field of Environmental Development Russian Federation for the period up to 2030”.
Method 2Garbage composting.
This method of processing MSW is based on the fact that some of the garbage can be disposed of independently - through biodegradation. So, organic waste is able to be composted. Nowadays there are special technologies composting food waste and unseparated garbage.
Mass composting is not widespread in our country, but is used by that part of the population that has private houses or summer cottages. However, in general, it is possible to organize the process of garbage composting centrally, by allocating special sites for this. The resulting compost can later be successfully used in the agricultural industry.
Method 3Thermal processing of waste (MSW).
Organics can also be easily destroyed thermally. Thermal processing of MSW is a consistent procedure for the effect of heat on waste in order to reduce their mass and volume, as well as neutralization. Such processing of MSW can be accompanied by the production of inert materials and energy carriers.
Advantages of thermal processing:
- Effectiveness in terms of neutralization (destroys pathogenic microflora).
- Significantly reduces the volume of garbage (up to ten times).
- Use of the energy potential of waste of organic origin.
The most common method of thermal processing of MSW is incineration. This easy way there are many advantages:
- It has been tested many times.
- Combustion equipment is available and commercially available, has a long service life.
- Automated process, does not require the involvement of labor resources.
If earlier garbage was simply burned, then modern technologies make it possible to use this process more efficiently, simultaneously extracting the fuel fraction from it. As a result of such techniques, the incineration procedure turns not only into the elimination of garbage, but also into the production of additional energy - electrical or thermal. The most promising this moment is a plasma combustion technology that provides more high temperature burning. As a result, useful energy is released, and the result is a completely harmless vitrified product.
Method 4Plasma recycling of waste (MSW).
Processing of MSW by the plasma method is a process of turning garbage into gas. This gas is subsequently used to generate steam and electricity. Non-pyrolyzable solid waste residues are one of the elements of plasma processing.
The advantage of high-temperature pyrolysis is that this process destroys a wide variety of wastes without any preliminary preparation, without harming the environment. From an economic point of view, this is a very profitable technology, since no additional costs are required for drying, sorting and other procedures for preparing waste for disposal.
The output is slag, which does not harm the environment and can even be reused.
What equipment is used for the processing of solid waste
The industrial world does not stand still, more and more equipment and waste disposal plants are becoming. The most common types of equipment for such enterprises include:
1. Presses.
Without pressing waste, it is impossible to imagine any plant for the disposal and processing of solid waste. After pressing, the waste is more convenient to store and transport. The presses can have different dimensions: from the most gigantic to relatively small ones that can fit in the territory of an ordinary store. In Russia, two types of presses are used:
- Packing presses.
- Briquetting presses.
According to the method of loading the press are:
- Vertical (front loading).
- Horizontal (capable of compressing debris more tightly).
While vertical presses are compact enough, horizontal presses are usually installed only in large factories, since they are difficult to fit in a normal room.
According to the purpose of the press, there are universal (for all types of waste) and specialized (for only one type).
2. Compactors.
Compactors are considered very close to presses. From the name it is clear that they also make the garbage more compressed. Basically, this type of equipment compacts PET bottles, polyethylene films, aluminum cans, as well as paper and cardboard. For shopping malls, this type of equipment is indispensable, because there is always a need for compression a large number garbage.
Waste transportation companies unanimously claim that transportation and storage costs are significantly reduced by compacting waste with compactors. At the same time, it does not matter at all whether this compactor is mobile or stationary.
Fixed and mobile equipment have their pros and cons. If mobile compactors are monoblocks, then stationary compactors contain a press and a replaceable container, which allows you to load much more waste than in a single monoblock. The continuous cycle of work also significantly distinguishes the stationary compactor from other waste equipment. Just have time to change containers.
But the mobile compactor can be used in different places, while it does not need to be mounted and dismantled again every time. This is a hermetically sealed design, which allows it to work even with wet waste.
3. Shredders.
Shredders have a completely different type of work than presses and compactors. They help in the disposal of garbage by crushing it or crushing it. That is why Russian-speaking users call shredders crushers. Not a single solid waste processing plant can do without them. Shredders are designed for grinding:
- glass;
- tree;
- plastics;
- paper;
- rubber;
- metal;
- organic and mixed waste;
- dangerous substances.
Some shredders only handle one type of waste, such as glass. But there are many models that are designed to grind a wide variety of garbage.
4. Containers.
We deal with this type of equipment every day. These are our usual waste containers, which we regularly use. The material from which the containers are made is usually plastic, although sometimes metal is also found. Containers can be used for separate storage of garbage or for mixed waste. Not so long ago, containers were stationary, now more and more often we see containers on wheels. From containers equipped with wheels, it is more convenient to transfer garbage to garbage trucks.
5. Sorting lines.
It is much easier and more efficient to process MSW in sorted form. As we have already said, for different kind garbage has its own ways of disposal, and therefore it is so important to first separate one type of waste from others. To this end, waste sorting lines are now mandatory installed at waste processing plants. Sorting lines are designed to separate municipal solid waste into fractions for the purpose of their subsequent pressing, compaction and transformation into secondary raw materials, which can then be sold. Sorting lines have become an integral part of the waste recycling process.
How a solid waste processing plant is completed
A set of equipment for any plant is selected taking into account its specialization. There are enterprises of a wide profile that carry out the processing of various types of solid waste. But small plants usually deal only with a specific type of waste. It can be construction waste, tires and other rubber products, household waste, etc.
It is safest to invest in functional and powerful equipment that can serve a large area, working without interruptions and breakdowns.
An example of such a complex is the waste incineration mini-plant MPZ-5000 (manufactured by Sifania (Russia)). It is designed to process a huge amount of municipal solid waste, for example, it will perfectly cope with five thousand tons of garbage per year. A mini-factory implies a set of equipment for burning garbage. The example we are considering is suitable for serving a small area with a population of about 25 thousand people. The set of equipment includes not only a waste incinerator, but also units for:
- waste sorting;
- shredding plastic bottles;
- waste paper seals;
- pyrolization of non-decomposable materials.
The cost of the equipment is quite high. Its simplest standard equipment will cost the company ten million rubles.
But this example is suitable for a small scale organization. For larger production, you can purchase a sorting station capable of passing through itself up to ten tons per hour. The productivity of such equipment is much higher than that of a mini-factory. This station is capable of separating 16 types of MSW from a mixed flow. Station maintenance requires at least 40 people. A good option for such equipment is the JSSORT complex. It has impressive dimensions. To install the entire station, you will need an area 40 meters wide and 80 meters long. Such equipment is capable of serving about 15 garbage trucks in one eight-hour working day.
Such a set of equipment will cost three times more than a mini-factory. Its cost is about 30 million rubles. This includes the cost of building a suitable space for the station.
A very profitable option for making money on waste disposal is a plant for processing rubber products (car tires) into small crumbs. After the operation of specialized equipment, only rubber powder remains, crushed into granules, which is perfectly suitable for recycling.
It is in demand in the production of:
- asphalt;
- road speed limiters;
- materials for soundproofing;
- mastic with anti-corrosion properties and other products of the construction industry.
A set of equipment for rubber processing is capable of processing up to three tons of waste per hour. An imported mini-factory of this type costs about 25 million rubles.
It should be noted that all processing enterprises have approximately the same set of constituent parts. The differences are mainly in the degree of their power and the level of process automation. The MSW processing plant includes the following equipment:
- receiving conveyor;
- inclined belt conveyor;
- sorting line;
- press machine for packing;
- pyrolysis plant;
- shredder for plastic;
- glass container.
Sometimes this set is complemented by a receiving shop with magnetic equipment for separating scrap metal.
Consider the scheme of operation of a mini-plant for the processing of solid waste:
- first of all, the waste stream goes through a magnetic receiver to sort the metal;
- the vertical conveyor transports raw materials to the sorting line;
- sorting complexes can be automated and separate waste using optical devices or semi-automated and use manual labor;
- all waste paper is sorted and sent to packaging;
- plastic products enter the grinding device;
- glass waste is sent to a collection container;
- all other waste goes to the receiving hopper, from where it subsequently enters the press for compaction. The further fate of such garbage is burial.
If recyclables are packaged, they can be sold or recycled, depending on which direction is provided by the plant itself. For example, one of the divisions of the enterprise may be a workshop for the production of toilet paper.
The main problems of MSW processing
Problem 1.Lack of funds.
Currently, waste is removed mainly at the expense of the population. But established regulations household waste disposal rates are prohibitively low. So much so that they are not able to compensate even for the transportation of garbage, not to mention its processing and disposal.
Of course, the funds collected from the population are not enough, so the rest of the resources are allocated by the state. But for unknown reasons, the housing and communal services never have the opportunity to develop and modernize the waste disposal system. We still do not have separate collection, as is customary throughout Europe. Yes, and at the material level there is no incentive to sort. If you throw out all the garbage in one container or separate the waste by type, you still pay the same tariff for the processing of solid waste.
Problem 2Secondary importance.
MSW recycling is currently carried out by organizations whose main activity is the provision of various utilities.
Only if specialized enterprises take over the collection and processing of waste, they will be able to carry out planning for more efficient waste collection, improve the equipment used, optimize income and costs for the processing of solid waste.
Problem 3.The absence of responsible persons.
All activities related to the disposal of household waste are dispersed among various departments. A single structure of hierarchy and responsibility in this matter has not been built. In European countries, things are different. There, the issue of household waste management is controlled by the Environmental Protection Agency. In our country, there is a similar authority - the Ministry of Natural Resources, however, the issue of MSW processing has not been transferred to the jurisdiction of this body.
As a result, the existing ministries and departments in varying degrees relate to this area, but shift the responsibility to each other, and the process of issuing bills in this area is delayed due to the lengthy approval procedure.
Problem 4.Concentration in the hands of state bodies.
Government agencies zealously hold on to the recycling of solid waste, although, as we have seen, they do not have enough funds, desire and understanding to organize the process at the proper level. European states show the effectiveness of involving private companies in this issue. In Europe, organizations have long collaborated with municipalities on waste collection and disposal. Perhaps, sometime in the future, our authorities will reach a similar level of cooperation, but for now, landfills are accumulating and continue to poison the environment.
Overseas experience shows that private companies are very enthusiastic about solving this problem, as it is directly related to commercial benefits. So, they are looking for the most efficient and cost-effective ways to process MSW. By building large factories and attracting foreign investment, commercial organizations work with great returns, and the result of their activities is evident.
Problem 5.No community outreach.
The fact that the population practically does not understand the benefits of separate waste collection is a sad flaw in the domestic management of this issue. After all, if citizens are informed about the problems of MSW processing, they may increase their awareness and desire to correct the situation, including on their own. After all, this planet is our home, where we live and plan to inhabit it for a long time to come.
Problem 6.Lack of fixtures.
The abundance of open access data allows many conscious citizens, despite the lack of centralized information, to come to an understanding of the problem of waste disposal. But even if people have a desire to throw garbage into separate containers, they are not given such an opportunity. The only equipment for collecting waste is an ordinary garbage chute. There is only one way out of the situation: weld all existing garbage chutes and establish a waste sorting system.
It is more expedient to design new houses without garbage chutes, since in general this will not only provide the possibility of separate waste collection, but also increase cleanliness in the entrances.
Problem 7.Recycling has not been arranged.
In Russia, there are organizations that are engaged in the processing of solid waste. There are not as many of them as we would like, but even these units often experience problems with the disposal of secondary raw materials. And this is sad, because in fact, the use of scrap allows you to get significant economic benefits.
To motivate the use of recyclable materials in production is again a state task. Moreover, we are talking not only about establishing obligations for enterprises, but also about developing a system of incentives, benefits, incentives that could encourage business representatives to establish markets for the sale of waste and its use.
Thus, in the implementation of public procurement in European countries, benefits are often provided for organizations that manufacture products from recycled materials.
Problem 8.Lack of planning.
In order to prevent the recycling of MSW and the use of recyclable materials from becoming local and episodic phenomena, it is necessary to draw up detailed plans aimed at achieving the desired results. Thus, this plan for the use of waste should cover a long period during which the necessary measures are provided, as well as the timing of their implementation, sources of funding, goals and persons responsible for the implementation of such actions.
All of the above problems actually arise due to the same factor: the task of competent processing of solid waste is not among the priorities at the state level. In addition, we still have not come to realize the most rational use of available resources. Therefore, environmental protection issues have not yet been resolved, and an effective waste disposal system has not been built.
What are the prospects for the processing of solid waste in Russia
In Russia, the idea of rational use of waste has not yet been developed. Recently, this area has received a little more attention. But only the smallest. A number of waste processing enterprises have been created in our country, but their functioning has not yet been put on a grand scale. The process is not adjusted, there is no competent interaction of such organizations with the state. In general, while such companies operate mainly in the central regions of the country - Moscow, St. Petersburg. But ideally, such activities should be carried out everywhere.
The fact is that in large cities there are much more earning opportunities for waste processing enterprises. The waste disposal business is very profitable where there is an abundance of it, and there are sorely lacking areas for storage and slow destruction of waste. Not so on the periphery. Most often, garbage is taken out to lands that are located on the outskirts of cities and towns. This method harms the environment and is also economically unprofitable. While the processing of ordinary household waste is a profitable business, and at this time in the domestic economy, this niche is free.
It should be noted that until the municipalities begin to perceive this problem as an urgent one, it is unlikely that anything will change dramatically. Foreign experience shows that a significant part of waste disposal issues can be solved by a simple action - the installation of containers for separate waste collection. This step will greatly simplify the processing of MSW.
The criticism of this assumption is the judgment about the inertia and laziness of Russians who do not want to sort their waste at home. But public opinion polls do not support this idea. For example, half of Moscow residents are already ready for separate waste collection. And this is without any propaganda and work with the population on the part of those in power. It is easy to guess that, subject to the actions of the state in this direction, a quick and effective transition to modern technologies for waste processing and the use of secondary raw materials is possible in our country.
Expert opinion
Solving the problems of MSW processing with the help of integrated management
L.Ya. Shubov,
Doctor of Technical Sciences, professor, member of the community of Russian experts on environmental management
HE. Borisova,
Candidate of Technical Sciences, Associate Professor of RSUTS
I.G. Doronkin,
Candidate of Technical Sciences, Associate Professor of RSUTS
MSW recycling management consists of the following elements:
- garbage collection;
- export;
- processing (preliminary preparation);
- actual processing;
- disposal;
- burial.
All these components are connected into a single system and are interconnected.
To ensure the solution of the tasks of MSW processing, it is necessary to be guided by modern requirements for resource conservation and environmental management:
- recycling of waste as sources of raw materials and energy;
- reducing the cost of cleaning settlements;
- transition from the method of MSW disposal to industrial utilization;
- ensuring environmental safety.
Changes are not so easy to achieve, because they are associated not only with the establishment of an effective system of garbage collection and processing, but also with the improvement of the sanitary and hygienic state of the city, and this is already a matter of reforming the housing and communal services. At the moment there are a number of tasks, among which are not last place occupy the creation of a market for services and the development of competition in the field of MSW processing. Implementing all these innovations is not easy.
At the moment, there is a serious shortage of specialists in the processing of solid waste. Universities annually issue diplomas to broad-profile environmentalists who do not yet own the technologies for the efficient processing of technogenic raw materials, it is difficult for them to find a solution to the problem with solid waste overnight.
Some foreign organizations are eager for Russian market, offering a way out of the difficult situation with MSW with the help of advanced technologies. But often it is only about burning garbage. A well-thought-out waste disposal system still does not arise. At best, industrial facilities appear chaotically, dealing with only one technology in the complex of measures necessary for the systematic destruction of waste. This is the road to nowhere.
It is impossible to solve the problem of MSW recycling by building waste incineration plants. While one is being built, he is finishing his life cycle another. Therefore, unsystematic construction has already proved its inefficiency. In this direction, one cannot rely on one single method of processing - incineration.
Practice shows that such a policy does not lead to a solution to the problem, but only contributes to increased environmental pollution.
It is necessary to take an example from the European states. Here is what they have achieved so far in terms of MSW management:
- Developed a recycling industry based on separate waste collection with the selection of usable elements.
- We organized and continue to develop a system of specialized sorting facilities, enterprises for thermal and biothermal waste processing.
- Developed a recycling system.
Burning all garbage is simply unacceptable. The waste fraction that has already been freed from both hazardous and resource-valuable components is used for thermal processing. Such production can be called environmentally friendly.
In our country, all MSW processing points are built haphazardly, out of touch with each other. The entire waste stream is sent there without prior sorting. Such actions create the threat of an emergency situation.
If the issue of solid waste is resolved, then the problem of environmental security of the country as a whole will be partially resolved.
There is an urgent need to build a system for processing solid waste for the Moscow region and the cities of the resort area. Until government policy on this issue is normalized, crime and corruption will continue to flourish. That is why the development of a science-based strategy for the processing of MSW is task No. 1.
The strategy for optimizing the integrated management of solid waste is needed, first of all, to create an advanced efficient waste management system and the use of secondary raw materials. The task of such a program is to develop ways to introduce waste into industrial processing, plan a sequence of actions to massively reduce the flow of garbage that is currently being disposed of, reduce environmental risks and waste disposal costs. The strategy should look like a single document with understandable and clear terminology, containing a real model for optimizing the use of waste.
The complex of technical and technological solutions that accompany the processes of waste management from the moment of their formation to the disposal of non-disposable components is the basis for management in the waste management system.
The main methods of waste processing are:
composting,
biodegradation,
incineration.
These methods are especially effective in the processing of MSW.
1. Composting.
Composting is considered a form of processing that targets raw organic waste matter. Composting is a biological method for the disposal of solid waste. Sometimes it is called biothermal method.
The essence of the process is as follows: various, mostly heat-loving microorganisms actively grow and develop in the thickness of the garbage, as a result of which it self-heats up to 60 0 C. At this temperature, pathogenic and pathogenic microorganisms die. The decomposition of solid organic pollutants in household waste continues until a relatively stable material, similar to humus, is obtained.
The mechanism of the main composting reactions is the same as in the decomposition of any organic matter. When composting, more complex compounds decompose and turn into simpler ones.
The cost of composting methods increases with the use of specialized equipment and can reach significant values.
The scheme of work of the waste processing plant is as follows . The completed cycle of MSW neutralization consists of three technological stages:
reception and preliminary preparation of garbage;
actually biothermal process of neutralization and composting;
compost processing.
Waste processing must necessarily be combined with the issuance of products that are safe and epidemiologically.
Waste disposal is provided primarily by the high temperature of aerobic fermentation. During the biothermal process, the majority of pathogenic microorganisms die.
However, the compost obtained as a result of biothermal disposal of MSW at waste processing plants should not be used in agriculture and forestry, because contains impurities of heavy metals, which through herbs, berries, vegetables or milk can harm human health.
2. Biodegradation organic waste
It is generally accepted that biological methods for the decomposition of organic pollutants are considered the most environmentally acceptable and cost-effective.
The technology of waste biodegradation process is different. For example: in bioponds - liquid waste, in bioreactors - liquid, pasty, solid, in biofilters - gaseous. There are other modifications of biotechnology.
Significant disadvantages of aerobic technologies, especially in the treatment of concentrated wastewater, are energy costs for aeration and problems associated with the processing and disposal of a large amount of excess sludge generated (up to 1–1.5 kg of microbial biomass for each kilogram of organic matter removed).
It helps to eliminate these shortcomings anaerobic wastewater treatment by methane digestion. At the same time, no energy is required for aeration, which plays big role in the conditions of the energy crisis, the volume of sediment decreases and, in addition, valuable organic fuel, methane, is formed.
The list of substances biodegradable anaerobically includes organic compounds of various classes: alcohols; aldehydes; aliphatic and aromatic acids.
Sequential multistage destruction of molecules of organic substances is possible due to the unique abilities of certain groups of microorganisms to carry out catabolic process – breaking down complex molecules into simple ones and exist due to the energy of destruction of complex molecules, having no access to either oxygen or other energetically preferable electron acceptors (nitrate, sulfate, sulfur, etc.). Microorganisms use carbon from organic substances for this purpose. Consequently, in the process of reductive fission, complex organic molecules are broken down into methane and carbon dioxide.
3. waste incineration
Municipal solid waste is a heterogeneous mixture in which almost all chemical elements are present in the form of various compounds. The most common elements are carbon, which accounts for about 30% (by mass) and hydrogen 4% (by mass), which are part of organic compounds. The calorific value of waste is largely determined by these elements. In industrialized European regions, the calorific value of MSW is 1900–2400 kcal/kg, and in some cases reaches 3300 kcal/kg, and a further increase in the calorific value of waste is predicted, which will affect the design features of the elements of thermal equipment.
MSW incineration is generally an oxidative process. Therefore, oxidative reactions also prevail in the combustion chamber. The main combustion products of carbon and hydrogen are CO 2 and H 2 O, respectively.
When incinerating, it must be taken into account that MSW contains potentially hazardous elements characterized by high toxicity, high volatility and content, such as various compounds of halogens (fluorine, chlorine, bromine), nitrogen, sulfur, heavy metals (copper, zinc, lead, cadmium , tin, mercury).
There are two main ways of formation of dioxins and furans during the thermal processing of MSW:
primary formation in the process of MSW incineration at a temperature of 300–600 ºС;
secondary formation at the stage of cooling of flue gases containing HCl, copper (and iron) compounds and carbon-containing particles at a temperature of 250–450 ºС (reaction of heterogeneous oxychlorination of carbon particles).
The temperature at which dioxins begin to decompose is –700 ºС, the lower temperature limit for the formation of dioxins is –250–350 ºС.
In order to reduce the content of dioxins and furans to the required standards (0.1 ng / m 3) during combustion at the gas cleaning stage, the so-called primary measures must be implemented, in particular, "two second rule" – the geometry of the furnace must ensure the residence time of the gases is not less than 2 seconds. in the furnace zone with a temperature of at least 850 ºС (at an oxygen concentration of at least 6%).
The desire to achieve the highest possible temperatures during combustion and the creation of any additional afterburning zones does not completely solve the problem of reducing the concentration of dioxins in exhaust gases, since it does not take into account the ability of dioxins in new synthesis with a decrease in temperature.
High temperatures lead to an increase in the yield of volatile components and an increase in emissions of hazardous metals.
Theoretically, there are two ways to suppress the formation of dioxins:
binding of MSW formed during incineration HCl using soda, lime or potassium hydroxide;
conversion of copper and iron ions into an inactive form, for example, the binding of copper into complexes with the help of amines.
Depending on the process temperature, all methods of thermal processing of MSW that have found industrial application or have undergone experimental testing can be divided into two large groups:
processes at temperatures below the melting point of slag;
Processes at temperatures above the melting point of the slag.
Layered MSW combustion is carried out on moving grates (grate and roller) and in rotating drum kilns.
3.1. Layer burning.
Burning on grates.
Everything grates are installed in a furnace, which is a combustion chamber, where waste and blast air are supplied as an oxidizer of organic substances.
Pusher screens with both direct and reverse material supply are a system consisting of movable and fixed grates for moving and mixing waste. Direct feed grates (translational-push grates) have a small angle of inclination (6–12.5 º) and push the material towards the slag discharge (in the direction of material movement). Reverse feed grates (reverse push grates) have a large angle of inclination (typically 21-25º) and push the material (bottom layer of waste) in the opposite direction to slag discharge and waste transfer. In this case, part of the burning waste layer returns to the beginning of the grate, which intensifies the combustion process.
Burning on roll grates.
Layered combustion of MSW on roll grates is widely used in industrial practice. When using furnaces with roller grates, Borrowed from the practice of burning coal, the material is moved using rotating rolls (drums).
The operating experience of plants that implemented layered combustion of MSW in furnaces with roll grates made it possible to identify a number of shortcomings:
unsatisfactory operation and negative environmental impact due to poor stabilization of the combustion process;
often the optimum temperature is not reached;
large yield of underburnt;
poor quality of slag;
significant loss of ferrous metals;
Operational complications when curb stone and large amounts of metal get into the furnace;
the complexity of organizing effective gas cleaning in case of unstable combustion of waste, etc.
The mechanical introduction of European equipment designed for direct combustion of unprepared municipal waste in Russia is unacceptable, since there is practically no waste collection in the cities of the Russian Federation.
Burning in drum kilns.
Rotary drum kilns for burning raw (unprepared) MSW are rarely used. Most often, these furnaces are used for burning special waste, including hospital waste, as well as liquid and pasty industrial waste that has an abrasive effect.
Drum ovens are installed with a slight inclination in the direction of waste movement. Furnace rotation speed from 0.05 to 2 rpm. Waste, air and fuel are supplied from the loading side. Slag and ash are discharged from the opposite end of the kiln. In the first part of the furnace, the waste is dried to a temperature of 400 ºС and then gasified and burned, usually at a temperature of 900–1000 ºС.
In the practice of waste incineration, drum kilns were previously often used as afterburner drums after grates.
The practice of using drum kilns as afterburner drums in waste incineration plants is considered obsolete and this technology is not included in the designs of new plants.
3.2. Burning in a fluidized bed.
Fluidized bed combustion is carried out by creating a two-phase pseudo-homogeneous "solid-gas" system due to the transformation of the waste layer into a "pseudo-liquid" under the action of an ascending gas flow sufficient to maintain solid particles in suspension.
The layer resembles a boiling liquid, and its behavior obeys the laws of hydrostatics.
It is believed that combustion in a fluidized bed in terms of environmental and economic parameters in some cases exceeds traditional layer combustion.
Furnaces for solid waste incineration in a fluidized bed provide the best mode of heat transfer and mixing of the material being processed, and these characteristics are superior to boilers with push grates. In addition, fluidized bed apparatuses do not have moving parts or mechanisms. However, the need to ensure the fluidization mode of the processed material imposes restrictions on its granulometric and morphological composition, as well as on the calorific value. In some cases, the process of combustion in a fluidized bed, especially in a circulating fluidized bed, is more expensive than layered combustion.
The productivity of furnaces for burning solid waste in a fluidized bed ranges from 3 to 25 t/h. The prevailing combustion temperature is 850–920 ºС.
Due to the fact that the temperature of solid waste combustion in a fluidized bed is 50–100 ºС lower than in layer combustion, the possibility of nitrogen oxide formation due to air nitrogen oxidation is significantly reduced, resulting in reduced NO emissions with exhaust gases.
The role of the coolant in fluidized bed systems usually performs fine-grained sand , the particle surface of which creates a large heating surface compared to traditional grate combustion.
After heating the sand with an ignition burner to a temperature of 750–800 ºС, the waste is fed into the fluidized bed, where it mixes with the sand and wears out during movement.
As a result of the good thermal conductivity of the sand, the waste begins to burn quickly and evenly. The heat released at the same time maintains the sand in a hot state, which allows you to work in autogenous mode without supplying additional fuel to maintain the combustion mode.
3.3. Burning at temperatures above the melting point of the slag.
Main disadvantages traditional methods of thermal processing of MSW are a large volume of exhaust gases (5000–6000 m 3 per 1 ton of waste) and the formation of significant amounts of slag (about 25% by weight or less than 10% by volume). In addition, slags have a high content of heavy metals and for this reason are only of limited use, mainly as bulk material in landfills.
To obtain a slag melt directly in the process of thermal processing of MSW, it is necessary to ensure that the temperature in the apparatus is higher than the slag melting temperature (about 1300 º C). This usually requires either the use of oxygen or the supply of additional energy. Replacing part of the blast air with oxygen at the same time reduces the amount of exhaust gases.
The most obvious way to increase the temperature of waste combustion is to reduce the content of the inert component (nitrogen) in the used oxidizer (air), the heating of which consumes a significant part of the released energy.
The second significant advantage of combustion in oxygen is the drastic reduction in the volume of flue gases and, consequently, the reduction in gas cleaning costs. In addition, the reduced concentration of nitrogen in the blast air makes it possible to reduce the amount of nitrogen oxides formed at high temperatures, the purification of which is a serious problem.
In the early 90s, Vanyukov metallurgical furnaces were proposed for the thermal processing of MSW at a temperature of 1350–1400 ºС. Combustion is carried out in a fluidized bed of bubbling slag melt, which is formed from CHPP ash and slag waste loaded into the furnace.
The mechanical transfer of this process for large-scale thermal processing of MSW cannot be carried out due to:
the fact that the efficiency of the Vanyukov furnace is very low due to the high temperature of the exhaust gases (1400–1600 ºС);
the fact that predominantly organic raw materials are processed for processing; MSW consists of 70–80% organic components. When heated, mineral substances pass into a liquid phase, and organic substances into a gaseous one,
lack of large-scale testing of the process in relation to MSW, which does not allow working out: loading and unloading units; automation of the process, taking into account fluctuations in the composition of raw materials, the composition and volume of exhaust gases, etc.; autogeneity of the process in relation to the heat treatment of waste as a heterogeneous mixture of many components that differ in composition, size and calorific value. It should be noted that fluctuations in the composition of MSW are not comparable with fluctuations in the composition of powdered concentrates sent for smelting in the Vanyukov furnace. Careful averaging of fluctuations in the composition of concentrates makes it possible to achieve fluctuations within 0.5%, while the initial MSW is practically not amenable to averaging;
high cost of the process and equipment.
Thus, it is most expedient to use combustion at temperatures above the slag melting temperature for processing not initial MSW, but for neutralizing slags or their enriched fractions formed in the thermal processes of MSW processing at temperatures below the slag melting temperature. The output of slag in these processes is 10–25% of the original MSW, which sharply reduces the required productivity of furnaces and allows periodically involving slag in processing.
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