X Международная студенческая научная конференция Студенческий научный форум - 2018

In our world, recourse consumption is increasing consistently by virtue of population size growth. This consumption is attended by the increasing of the amount of wastes. Human life and activity lead to refuse dumps.

And it is logical that there is a strong probability of turning our planet into a giant dump unless we do not apply new methods of recycling. And it is no wonder that scientists are constantly inventing and adopting new methods of waste recycling. . But what methods are being used nowadays?

Landfill. It includes:

Waste classification or sorting;

Filling earth (dirt fill).

Waste sorting involves fraction separation of household wastes (or solid domestic waste). That includes the process of recovery of the most valuable recyclable materials and their further decreasing (reduction) using shredding (grinding) and screen separation.

In general, solid waste separation goes before its further utilization. As this procedure is very important, nowadays almost every refuse dump has its own waste disposal and recycling plant. This particular kind of plant gets fractions of different materials such as metal, glass, paper, plastic, etc. for the purpose of its further separate recycling.

Domestic waste landfill is considered to be the most popular way of waste reclamation and utilization. The method is applied to noncombustible refuse and to kind of refuse that emit toxic gases under combustion (in the process of combustion).

Domestic waste landfill is not a usual normal dump. Modern landfills for reclamation are complex engineer constructions, tooled up with anti-groundwater and air-pollution systems.

The main disadvantage of traditional landfill is even using numerous cleaning systems and filters this way of utilization is not able to get rid of some negative breakdown effects such as decay, rotting or fermentation that contaminate, pollute air and water. That is why domestic waste landfill although is cheaper in comparison with other methods of utilizations not preferable; ecologists recommend recycling, thereby minimizing risks of environmental pollution.

Sanitary landfill is approach to decontamination, neutralization is inextricably connected with landfillgas (biogas) recouping and its further using as clean, pollution-fee fuel. In this case domestic waste is covered with a layer of soil approximately 0.6-0.8 meters. Existing of organic components in refuse masses and pores lays the ground work for microbiology processes development. As a result, biogas is produced. Therefore, dumps are the biggest systems of biogas production.

Natural methods of breakdown include:

Composting. It is a recycling technology based on waste natural deterioration. For that reason composting is widely spread in organic waste recycling. It is normally used by people in their houses or garden plots. Final,or end product of this process is compost, that can be used agriculture. However, for realization, for implementation of this technological scheme initial waste should be cleaned off from large objects, metals, ceramic, plastic, glass and rubber, as compost must not contain such materials.

Thermal utilization includes:

Incineration (burning)

Low-temperature pyrolysis (torrefaction);

High-temperature pyrolysis .

From all this great variety of methods incineration is the most popular one.

As mentioned before, Solid domestic waste burning is considered to be a widespread method of waste utilization that has been used for more than a hundred years. Burning provides significant decrease of waste amount and mass, allows us to receive some extra energy resources within the utilization process. These resources can be used for power production. Obviously, this method has lots of advantages, but it has some disadvantages as well.

One minus is that harmful substances are being emitted during the burning process and some valuable, essential organic components that we may find in waste are being destroyed.

Nowadays usage of plasma technologies is considered to be the most promising method. Thanks to these technologies the temperature that is higher that the temperature of slag (ash) melting is provided, and as a result, we have harmless vitrified products and useful energy.

Plasma recycling

It is the process of waste conversion, gasification. In its Technological scheme gas production is supposed. We receive this gas from biological component and use it for steam and power generation. Solid waste in form of elements that cannot be pyrolysed or ash constitutes part of the plasma process.

Apparent advantage of High-temperature pyrolysis is that this methodology gives an opportunity to eco-friendly and technically simple waste recycling and utilization without any advance preparation ,e.g. drying or sorting. And needless to say that usage of this methodology is way more profitable than usage of obsolete, old-fashioned methods. Furthermore, slag or ash that is produced with help of this technology is absolutely harmless and can be used afterwards for different purposes.

Recycling of waste into fuel.

There is some domestic waste that forms mixture, blend of organic substances that have different origin. It is nothing else but high-caloric fuel which energy is highly competitive with one of brown or wood coal. To confirm these words, we should refer to experience of West European counties where the utilization problem is being solved successfully in recent years.

For instance, in Copenhagen (the capital of Denmark), approximately 30% of heat for district heating supply system is gotten thanks to thermal waste utilization.

Considering household waste a renewable energy source, we take people’s economic concern into account. Considering steady increase of energy tariffs, domestic waste as a type of alternative fuel is getting more relevant.

Getting power from rubbish, we are at the same time solving the household waste utilization problem and receiving cheap, almost free thermal, heat energy. This energy can be used for communal heating resources supplement. And use of waste utilization modern technologies in process of solving waste utilization problem makes possible landfill negative effects on environment decrease.

From waste we can get not only energy, but fuel as well. Fuel made from common rubbish may be divided in:

Gaseous;

Solid;

Liquid.

Now we are going to talk about methods of producing these substances in more detail.

We can get gaseous fuel from organic waste materials. In developed countries where biogas technologies are developed quite well, with a help of gas produced from edible and plant by products or waste whole estates are heated.

However, we have to mention that gaseous fuel stands transportation, undergoes transportation badly. That is why this type of fuel is generally used in situ to produce heat and electrical energy.

Solid fuel extracted from domestic waste is a high-caloric fraction made from domestic rubbish. This type of fuel is widely used as a cheap substitute for fossil fuels.

One of the main advantages of solid fuel from domestic waste are its constant heating,calorific value and its standard form. All this makes management and control over incineration process far more easier, because with this fuel high-quality incineration is provided.. What’s more, this process almost is no-waste. That is why there is no surprise that waste utilization by producing solid waste and its further incineration (instead of traditional domestic waste incineration) nowadays is considered one of the most efficient methods of recycling.

People learned how to produce liquid fuel not long ago, but the result surpassed, exceeded all the scientists’ expectations, because at the end of the process they got synthetic diesel fuel oil that can be used in internal-combustion engine.

Home-recycling

Composting as a waste utilization method

Organic waste is completely rotten in one-two years and turns into gererous,fertile nonorganic humus that is rich with minerals and is considered to be a good fertilizer for most of the plants . Moreover, gardeners notices that compost helps to grow better to such vegetables as marrow, pumpkin and squash. Therefore its possible to combine the useful with the pleasant and plant these vegetables on a compost heap or pile in order not to waste soil.

Composting is non-waste , provided that it is used properly because you kill two birds with one stone: first of all, it gives you an opportunity to keep your house and garden in order , utilizing garbage. Secondly, you can recycle waste into a high-quality fertilizer for free.

Bioreactor (fermenting box)for waste utilizing

As treatment facilities for home waste recycling simplest biogas units can be used . Advantage of using such units is that besides just simple solid waste recycling with this unit you can get energy that may be used for different purposes: for warming it up, for organization of gas supply system, electrical and heating energy generation.

Benefits from biogas units are the following:

Energetic. Utilizing household waste with this method, we receive power and heating from the biogas produced.

Economic. Thanks to biogas unit you save money on waste utilization

Boigas unit can be used as autonomic source of energy in some distant regions. It is not a secret that even nowadays a lot of houses in distant regions of Russia are heated with firewood. And installation of such biogas station would be a great solution for residents of these regions.

In this paper different methodics of waste recycling and methods of its conversion into fuel were systemized. To sum up, we would like to point up that profound studies of waste utilization and of environment preservation aspects guide future engineers to scientific and technological progress acceleration ,while solving environment-oriented problems in our cities and towns.

List of used literature:

1. Kuznetsov V.L. Krapinska N. M., Yudina L. F. Environmental problems of solid waste. Collection. Liquidation. Disposal: Training manual.-М.:IPC MIKHiS, 2005.

2. Bobovich B. B. Processing of industrial waste. Textbook for high schools. — М.: "SP Intermet INZHINIRING ", 1999.

3. Shubov L. Y., Stavrovsky M. E., D. Chigirev D.V. Technology waste (Technological processes in the service): textbook.-GOYVPO «МGSU».-М., 2006.

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