On the need for waste recycling

It is known that the life function of man is associated with the production of decomposition products, food and industrial waste (1.5 liters per day). Some of this waste must be treated in the right way, otherwise it can cause serious environmental damage. In addition, the period of degradation of many materials is more than a hundred years. The heavy pollution of the planet and the unsolved garbage problem have led to global changes - the destruction of the environment for living organisms. Garbage disposal, especially in large cities, has become a big problem of our time. None of the developed or developing countries can boast of having a well-established waste recycling system. Nowadays, only up to 70% of waste gets a second existence through recycling, and what do you have to do with the remaining 30%? Incineration or landfilling is not a rational option, which further exacerbates the already tense situation.

The global trend to recycle as much as possible causes manufacturers of machinery and equipment to build specialized mini-plants that have many advantages over landfill:

- up to 95% of waste is recycled;

- they take up little space;

- the constructions are mobile - this makes it possible to place the plant near landfills and large enterprises;

- quick payback - you can get a net profit in the first two years of operation of a mini-plant;

- Environmental friendliness-Recycling does not pollute the environment and does not cause toxic emissions to the atmosphere or nearby water bodies;

- Minimum number of employees involved in the action.

Morphology of waste

Approximate composition of municipal solid waste in the city. The morphological composition varies from country to country and from region to region!

Components of municipal waste in percent by weight:

• Food waste 30 - 38%
• Paper and cardboard 25 - 32%
• Plastics 7-15%
• Glass 5 - 8%
• Ferrous metals 3 - 6%
• Non-ferrous metals (aluminum cans, etc.) 0,5 - 1,5%
• Textiles 4 - 7%
• Wood 2 - 5%
• Bones 1 - 2%
• Leather and rubber 2 - 5%
• Stones, rubble 0,5 - 2%
• Hazardous waste (batteries, accumulators, solvent containers, picture tubes, mercury lamps, etc.) 0,5 - 1,5%
• Other 8-12%
• Construction waste 3,5 - 5%

Waste classification

Methods for defining hazard classes

• Calculation method;
• experimental method.

Calculation method.

The hazard class of waste is determined using the calculation method, if the amount of the disposed product and its qualitative composition are known. The hazard class is determined according to the concentration of the harmful component in the waste. This is carried out by specialists in an accredited waste management laboratory using qualitative and quantitative chemical analyses. For this purpose, the following properties are investigated:

• Water solubility;
• Persistence;
• Ways of entry into the body.

The main stages of the investigation are:

1. Study of the composition of waste materials. Determination of the harmful components of individual waste elements in the last technological cycle.
2. Chemical analysis and calculations.
3. The data obtained are compared with the table to determine the degree of threat to the environment.
4. Waste materials are assigned to a category.

Experimental method

Classification of waste is carried out according to the experimental method, when it is not possible to determine the quantities and components of waste. This method is used to confirm the calculation method.

Table of waste hazard classes:

1. Maximum degree of threat. There is no recovery period. The natural balance is completely destroyed.
2. high grade. Severe pollution of nature, the restoration will take 30 years.
3. moderate degree. After eliminating the dangerous effects, ecology will return to its original form in 10 years.
4. low degree of threat. After eliminating the threatening factor, the previous state returns after 3 years.
5. minimum degree of threat or no threat. No impairment of the natural balance.

SHW and SMW decryption

These abbreviations refer to the following points: SHW - solid household waste produced by private individuals in their households; SMW - solid municipal waste is solid waste produced by legal entities and natural persons. This is a more modern concept that has replaced the term SHW in documents.

Hazard classes of municipal waste

The waste produced by people, enterprises is divided into five classes depending on the degree of environmental damage. There are four dangerous groups and a fifth, which is relatively safe.

Waste hazard classes are:

1. 1st class-the degree of damage is very high, after contact with it, nature is not restored, the ecological system is destroyed. Mercury-containing objects, medical thermometers, galvanic elements, lamps (fluorescent), pressure gauges and other devices.
2. 2nd class-the degree of danger is high. These are wastes, after the impact of which the environment will regenerate only in at least 30 years. Accumulator batteries, used automotive parts, hazardous chemicals such as sulfuric acid, lead, arsenic, styrene and other harmful compounds.
3. class-Medium degree of hazard. Hazardous waste, relatively hazardous to the environment. The effects are short-term and equalize within 10 years. Acetone, paints, petroleum products, metal products, lead, building materials, household appliances, waste oil (oils, filters). Oils are divided into:
   • Motor oils;
   • Industrial oils.
4. class-Low degree of impact. Slightly dangerous items that cause minor damage. Nature recovers within 3 years. Construction waste, asphalt breakage, well cleaning waste, road waste, contents of cesspools, putty, bricks, building hardware, crushed stone, bitumen, old furniture, road waste, broken glass, sawdust, manure, chalk, bronze dust, cast iron dust, etc.This type of miller most often appears after construction work or when keeping animals or birds.
5. grade-the degree of danger is very low. Wastes that do not pose a threat to nature. The impact on human health and the environment is minimal. Food waste, paper, cardboard, eggshells, wood chips, sawdust, chips, paper, ash, ceramics, gypsum waste, abrasives, scale, cement, plastic containers, metal scrap, cable, electrical tape, polyethylene film, iron barrels, etc

Types of recycled waste

• solid municipal waste;
• Tailings-non-recyclable waste from waste treatment plants;
• Long-life sludges from sewage treatment plants, sludges from sewage treatment plants;
• oily residues, sludges, acid tar sands, etc.;
• Waste from poultry farms, including dead poultry, melange;
• Various chemical components of organic origin;
• Medical waste, pharmaceutical waste;
• Waste from the manufacture of particle board, sawdust, bark and chips from wood processing;
• Waste from the textile industry, rubber;

Operation of a waste incineration plant using the example of municipal waste

The principle of operation of the plant is based on filter combustion in the superadiabatic regime, which is achieved by the formation of a countercurrent "combustible oxidizer", the use of the generated static electric discharges (effect of the "cold" plasma at the temperature above 2000С), as well as the decomposition of the moisture contained in municipal waste into hydrogen and oxygen. This plant requires for thermal neutralization, no use of natural gas, diesel fuel or other energy sources. At the same time, the energy costs for the operation of the plant are ten times lower than the energy produced. This system consumes, for example, only 0.5-1.0 kWh of electricity, when connected to heat consumers it generates heat energy, with additional equipment with a steam-gas generator it generates electricity.

The advantage of this plant is that no prior treatment (crushing, drying, sorting) of municipal waste is required, and the amount of ash residues is 1-3% of the weight of recycled municipal organic waste.

In addition, the ash residue belongs to hazard class 5 and can be used as a filling in road construction or buried without environmental requirements. Without additional treatment, pollutant emissions into the atmosphere are within ecological limits. Compared to existing technologies for the thermal neutralization of municipal waste, including pyrolysis plants, which require additional energy resources for the conversion of municipal waste into gaseous, solid and liquid fractions, which then still need to be processed and transported to the consumer, "cold plasma" has a number of obvious advantages. However, the use of pyrolysis products is associated with significant environmental problems, and in the preparation of the pyrolysis process, the solid municipal waste must be dried and crushed beforehand.

The plant is available in a modular design with a capacity of 5 to 60 m3 of solid waste per day. The plant is assembled in standard 20-foot mobile containers that can be transported by any means of transport and designed as an extension of the number of modules to the required productivity.

The principle of operation of an incinerator

The basic principle of the technology is based on the destruction of the charged raw material by spontaneously occurring electrical discharges in the reactor chamber, which create a flame cloud with a temperature in the destruction zone of over 2000C. Micro-explosions occur, which cause immediate decomposition of the raw materials, releasing free carbon, hydrogen and oxygen. The commercial product here is the thermal energy and inorganic residues (in the treatment of sewage sludge, up to 30% of sand is allowed.

The cold plasma reactor uses a two-chamber furnace. Superadiabatic combustion and filtration combustion are used to ensure up to 99% recovery of organic raw materials. Solid municipal waste with a moisture content of up to 80% is accepted for disposal. The main feature of combustion is the filtration of the gas, which not only participates in the chemical reaction, but also acts as a coolant, forming a thermal structure with combustion waves of two temperatures.

The plasma is characterized by high efficiency, safety and the absence of secondary contamination. Plasma recycling plants offer the advantages of high operating efficiency, low processing costs, investment savings and easy operation. The basic principle is to break down waste molecules into elementary components, and then combine these elements into harmless compounds.

Advantages of technology

• This technology does not require pretreatment of the waste;
• This technology allows the planning of technological complexes without capacity limitation;
• The disposal takes place with the plasma process directly in the waste mass at the junction of the heterogeneous materials without additional costs for the electrical energy for plasma generation;
• Feces and industrial effluents can be used as oxidizing agents;
• The environmentally friendly disposal of solid municipal waste is guaranteed. The CO2 content in the flue gases is less than 2 %, all other harmful gases are either absent or do not exceed the maximum permissible concentration. In addition, the flue gases contain up to 20% oxygen;
• The stable disposal of all carbon-containing waste with a moisture content of up to 80% is ensured;
• No emissions into the atmosphere exceeding the maximum permissible concentration;
• Relative simplicity of construction of the complex;
• Short deadlines for the construction of the complex, the installation of equipment and its installation;
• Low cost of the complex in comparison with analog products;
• Low operating costs;