RU2837926C1 - Method for thermal recycling of sewage sludge in “к-туо” process complex - Google Patents

Abstract

FIELD: performing operations.

SUBSTANCE: invention relates to processing of multicomponent sediments of biological treatment of municipal and industrial waste water: wastes from grids or other filtering equipment, wet sediment, flotation sludge, fat- and oil-containing components from special-purpose settling tanks, excess active sludge, as well as carbon-containing (organic) wastes of industrial enterprises with moisture content of less than 80%. Implementation of the claimed invention is determined by a logical sequence of stages of treatment of sludge and carbon-containing (organic) waste water, including stages of dehydration, drying and burning, taking into account the formation of the best conditions for thermal action on waste water sludge, and achieving optimum temperature effects with the possibility of combustion thermal energy recuperation in a rotary incinerator for heating diathermic oil, which is a heat carrier of the drying process in a blade dryer. Stability of implementation of technological process and reliability of production of single-fraction treated sediment in form of ash of 4 or 5 hazard class are achieved. Emissions into atmosphere of gaseous combustion products do not contain concentration of components exceeding MPC.

EFFECT: use of the proposed method provides an improvement in the environmental situation in the territory occupied by the waste water treatment plants, and in the territories adjacent to the waste water treatment plant, as a result of the method implementation, an environmentally safe product is obtained, which can be used in road construction, in municipal services, as well as in agriculture for alkalization of acidic soils.

6 cl, 6 dwg, 3 tbl

Description

The invention relates to the field of processing multi-component sediments of biological treatment of municipal and industrial wastewater, including screen waste or other filter-type equipment, raw sediment, flotation sludge, fat and oil-containing components from special-purpose settling tanks that are not advisable to reuse, excess activated sludge, as well as carbon-containing (organic) waste from industrial enterprises with a humidity of less than 80%. When implementing the proposed technology, a dehydrated and environmentally non-toxic single-phase product is formed, which is advisable to use for landscaping with elements of landscape improvement, in road construction and agriculture. The resulting product is also intended for storage in a solid state (both in briquettes and in bulk) with subsequent disposal with 100% safety for the natural environment.

Since the disposal of wastewater sludge is one of the most important tasks in reducing the level of anthropogenic impact on the environment, the number of proposed methods for their processing is increasing. At the same time, methods are proposed both with the use of various additives, reagents, and without them.

A method for the comprehensive processing of man-made sludge is known (see Russian patent for invention No. 2057725 C1, authors: Esin A. V., Anufrieva S. I., Malikov V. A., Dvoskin G. I. et al.), the invention relates to the comprehensive processing of man-made solid waste, in particular bottom sediments of rivers and reservoirs, galvanic sludge, sludge of excess activated sludge from biological treatment facilities and other products. The method includes separating sediment into fractions with subsequent separate processing of each fraction and obtaining useful recyclable products, wherein after dehydration and separation of the sand component of the sediment, using a drum screen or hydrocyclone, the sludge component is divided into fractions in a ratio depending on the content of organic and inorganic substances, wherein from one fraction, by pyrolysis of the sediment and activation of the obtained solid residue with a mixture of flue gases and water vapor, a sorbent is obtained, from another fraction after treatment with sulfuric acid an iron-aluminum coagulant is obtained, and the third fraction of plant waste is used as a substrate for cultivating fungi or microorganisms at a relative air humidity of 90% and a temperature of 17°C to form fruiting bodies.

The disadvantage of this method for implementing the claimed method is the presence of a separate production site for processing three different types of sediments, including bottom sediments. The patent does not reflect in detail the scheme for separating sludge sediments into fractions, while it is obvious that each of the fractions will contain impurities of other fractions. Pyrolysis of sediments involves the formation of a liquid pyrolysis sediment, which in turn requires disposal. This scheme seems difficult to implement, especially in terms of cultivating fungi and microorganisms without the specified technology for their use. Thus, the multi-stage nature and complexity of the implementation of processes and obtaining various products without recommended use reduces the reliability of the process and its feasibility for solving the problem.

A method for the comprehensive processing of wastewater sludge is known (see Russian Federation Patent No. 270 8595 C1, authors: Khripach N. P., Kamnev E. G., Zhegulin S. N.), which involves processing a mixture of raw sludge and excess activated sludge, including pre-dewatered sludge containing heavy metals, with a decrease in humidity from 98-99% to 80% or less, including on sludge maps. A binding inorganic mineral additive (or a binding inorganic mineral agent) is added to the dewatered sludge, fed into a crusher-mixer for mixing, then fed for granulation and then to the stage of natural drying in an aerated room. After the stage of natural drying, the granules are subjected to heat treatment by firing in an activator without air access. The processing temperature is determined by the clay firing temperature, which is no higher than 200-300 ° C.

The disadvantage of the method under consideration for implementing the proposed method is the multi-stage nature of the successive drying processes, including on open sludge beds, the introduction of significant quantities of various ingredients of mineral origin, the use of roasting without air access at the final stage, essentially pyrolysis, in which the by-product is not only gas, but also liquid pyrolysis waste, the processing of which is not expected. Also, a method for cleaning gas emissions is not provided. Thus, the multi-stage drying processes, especially on sludge beds, and then during aeration in the room will require significant air exchange with the processes of processing the air of the room in order to prevent the spread of foul odors. The use of firing at the specified temperature, especially for granules of 10 mm in size, does not guarantee, as practice shows, complete sintering of the material and, therefore, there remains the possibility of its incomplete disinfection; all of this reduces the reliability of the process of disinfecting sludge sediments, while the disposal of other types of sediments formed at wastewater treatment facilities is not considered, therefore, this method is not advisable to use to solve the stated problem.

A method is known for obtaining products of thermal destruction of sludge sediment from municipal wastewater (see Russian Federation Patent No. 2776712 C1, authors M. I. Veprintseva) which includes preliminary placement of sludge sediment in the cavity of a storage bin, displacement of ambient air oxygen from the locations of the sludge sediment by means of supplied heated flue gases, its transportation for thermal destruction, followed by separation of the thermal destruction products into a gaseous mixture and a solid fraction. In this case, the sediment is heated in stages, first heated by flue gases to 50-80°C when it is fed into the cavity, then to 310-340°C by transferring thermal energy to it as a result of rotation of the horizontal spreading disk and by means of heat transfer from steel elements of the screw conveyor heated to 310-340°C, which is formed to carry out thermal destruction by increasing the temperature in the chamber wall to 800-810°C.

The disadvantage of the specified method, which prevents the implementation of the claimed method, is the need to use sludge sediment of municipal wastewater with a humidity of 8-20% and with particle sizes of 0.2-0.4 mm., step-by-step heating of the sediment to the specified temperatures requires strict control of the flue gas temperature. Also, the use of this method is limited to the processing of sludge sediments and does not provide for the neutralization and / or disposal of waste from grates, raw sediments, as well as emulsifying products - fats, oil products, etc. The temperature conditions and methods of moving sludge sediment specified in the method are not suitable for all types of wastewater sludge declared for neutralization by the proposed method.

A method for processing and recycling household and industrial waste with the production of thermal energy and marketable products and a set of technical means for eco-production for its implementation are known (see Russian Federation Patent No. 2828716 C1, authors Gorshkov A.S., Efimov O.I., Samokhin M.A., Gerasimov O.A., Bondarenko N.V.), which proposes processing and rendering harmless household and industrial waste from urban infrastructure for processing and recycling food and solid combustible components of household and industrial waste with the production of thermal energy and marketable products and contains a bunker unit, a household and industrial waste sorting unit, an incineration plant, a food waste storage unit, a feed mixture and fertilizer preparation unit. In this case, the incineration plant contains a combustion unit, a smoke purification unit, a water treatment and heat recycling unit and an ash recycling unit. The specificity of this method is the utilization of combustible materials, which do not include food waste, unlike wastewater sludge, which includes this waste, therefore, the preparation of wastewater sludge and household waste is different, and the temperature effects are different. Flue gases will also contain various impurities and, therefore, the proposed method cannot be applied in the declared form to solve the tasks set.

The objective of the proposed invention is to develop a unified method for thermal utilization of wastewater sludge in the K-TUO technological complex, including all types of sludge generated in the process of biological treatment of municipal and industrial wastewater: screenings or other filter-type equipment, raw sludge, flotation sludge, fat and oil-containing components from special-purpose settling tanks, excess activated sludge, as well as carbon-containing (organic) waste from industrial enterprises with a humidity of less than 80%, while simultaneously achieving stability in the implementation of the technological process and the reliability of obtaining a single-fraction processed sludge in the form of ash of hazard class 4 or 5, as well as emissions into the atmosphere of gaseous combustion products containing component concentrations not exceeding the MAC in the atmosphere, as well as a reduction in fuel energy consumption due to heat recirculation, which will improve the environmental situation in the territory occupied by wastewater treatment facilities and in the territories adjacent to the wastewater treatment facilities, also as a result of implementing the method They obtain an environmentally friendly product that can be used in road construction, in urban management, and also in agriculture for alkalizing acidic soils.

The technical result of the claimed invention is a sequence of implementation of stages of processing sludge and carbon-containing (organic) wastewater, taking into account the formation of the best conditions for thermal impact on wastewater sludge, and the achievement of optimal temperature effects with the possibility of recovering thermal energy and reducing fuel consumption.

The technical result is achieved by the fact that first the components of the sewage sludge undergo special preparation, the screen waste is crushed, then dehydrated, the activated sludge is dehydrated, dehydration is carried out using mechanical equipment to a humidity of 85% to 72%, the use of mechanical equipment for dehydration allows to speed up the process, as well as reduce emissions of volatile foul-smelling substances into the atmosphere, then the dehydrated sewage sludge is sent to a dehydrated sludge receiving bin equipped with a ventilation system and screw conveyors installed at the bottom of the bin for mixing the sludge. Mixing (stirring) the sludge prevents fermentation processes, facilitates further transportation and feeding into the receiving funnel of the dosing screw pump installed directly under the bin and designed to transport portions of dehydrated sludge to the paddle drying unit. The design of this type of dryer is quite simple. The main elements of the drying unit are a rigid body with an integrated frame, two counter-rotating hollow shafts with special wedge-shaped blades separating the sludge into separate fractions that come into contact with a hot gas medium with a temperature of at least 105°C, and a cover. Blade dryers are manufactured in a wide range of capacities and have proven themselves well in sludge drying practice. The specifics of the internal structure of the blade dryer allow to reduce its dimensions, which is important since, as a rule, the area of the land plot used by treatment facilities is limited. The sludge is heated by heat transfer from the coolant through a metal barrier. Diathermic oil is used as a coolant, which has increased resistance to aging, is distinguished by high temperature stability and allows to obtain higher temperatures of the working medium at low pressures, which significantly reduces production costs for maintaining the temperature of the diathermic oil and increases the efficiency of the system as a whole. Diathermic oil is prepared by heating it to 200-250°C depending on the operating conditions of the technology in two options. The first option involves heating the diathermic oil in a thermal oil boiler house, this option is used when starting the K-TUO technological complex into operation, or in periods when the recovered heat from sludge combustion is insufficient for the sludge drying process (as practical studies have shown, such a situation is extremely rare). The main units of the thermal oil boiler house are a boiler consisting of 2 cylindrical coils following one another, which are located in one combustion chamber and a circulation pump that supplies the heated coolant to the blade dryer unit and the purge air heat exchanger. According to the second option, diathermic oil is heated during the continuous operation of the technological complex, due to the recovery of thermal energy from the combustion unit. The proposed scheme for preparing diathermic oil during the operation of the K-TUO technological complex allows for a significant reduction in fuel costs, since the thermal energy of combustion of wastewater sludge, as shown by the pilot experiment, is carried out at a temperature of 650°C to 850°C and allows maintaining the temperature of the diathermic oil sufficient for drying the sludge in a paddle dryer. Drying of the sludge in a paddle dryer is carried out to a humidity of 10% to 30%. During the drying of the sludge, evaporations are formed consisting of evaporated moisture, heated purge air and a dust fraction of the dried sludge. To remove fumes, heated air is supplied into the body of the paddle dryer, the fumes move into the discharge channel through the outlet opening located in the middle of the cover arranged on the body of the paddle dryer, and are first sent to dry gas cleaning in the mechanical cleaning unit - inertial cyclones, in which mechanical impurities are deposited from the fumes, and then the fumes are sent for cleaning to the gas washer (Venturi scrubber), in which condensation of the fumes and wet cleaning from small dust fractions occur. The scrubber uses process water circulating in a closed circuit and fed by a pump to the sprayers, contaminated water after the gas scrubber is sent to sewage treatment facilities or for burning in a rotary incinerator, in a liquid waste collection unit, purified vapors are removed from the scrubber through a special fan, which also serves to create a small vacuum in the paddle dryer system, which ensures that the vapors cannot bypass the gas cleaning facilities. The dried sediment is removed from the paddle dryer through an opening arranged at the end of the paddle dryer, while pouring through a special barrier at the end of the paddle dryer, the dried sediment can be molded into granules measuring 0.5 by 0.5 cm, the size of the granules is optimal and is determined during the research. If the granule size is higher than the specified one, then, during their combustion, the sediment may not be completely ashing, which is manifested by the presence of a sediment in the center of the granules that is morphologically similar to the dried one. Then, the dried granulated or loose sewage sludge is sent to a screw conveyor for transportation to the incineration unit, to a rotary incinerator, which consists of two chambers: a combustion chamber and an exhaust gas afterburning chamber. First, the dried sewage sludge is fed to the loading module, then dosed, using a screw feed system, it is sent to the sludge loading unit, from which the dried granulated or loose sewage sludge is sent to a screw conveyor for transportation to the combustion chamber of the rotary incinerator, which is a rotating drum, while the temperature in the combustion chamber should be maintained from 550 ° C to 800 ° C, when the temperature reaches 650 ° C, the burners are automatically switched off. Ash is discharged from the ash bin using a screw conveyor and sent to the cooler, from which the ash is transported by a screw conveyor. During combustion, the sediment moves to the discharge ash bin, while the ash is discharged from the ash bin using a screw conveyor and sent to the cooler, the operating principle of which is based on the conductive method of transferring thermal energy, cooling liquid, in this case circulating technical water is used. From the cooler, the ash is transported by a screw conveyor to the big-bag loading unit. Exhaust gases formed during the combustion of wastewater sludge under the action of vacuum enter the exhaust gas afterburning chamber, equipped with its own burner device, where they are at least two seconds at a temperature of 850 to 950 ° C. The temperature difference in the combustion chamber and in the gas afterburning chamber should be about 200°C, which is dictated by the design features of the rotary incinerator. When the temperature in the gas afterburning chamber reaches more than 9000C, the burners of the gas afterburning chamber are automatically switched off. Maintaining the temperature in the combustion chamber above 700-800°C is technologically and economically impractical, since the temperature difference between the combustion chamber of the rotary incinerator and the exhaust gas afterburning chamber should be about 200°C, therefore, an increase in the temperature in the combustion chamber will entail an increase in the temperature in the afterburning chamber. The significant thing in the proposed method is that after artificial ignition of the sediment in the combustion chamber, combustion of the sediment occurs further without additional heat from external sources, due to the high heat capacity of the sediment.

After the gas afterburning chamber, the hot gases are directed through a heat exchanger, where the diathermic oil used as a heat carrier for the paddle dryer is heated. To implement the process of heating the diathermic oil, it circulates in a closed circuit: the recuperator of the rotary incinerator - the paddle dryer - the recuperator of the rotary incinerator. The cooled gases after the heat exchange equipment enter the dry-type gas cleaning unit (GPU) through a system of chimneys, represented by cyclone filters, a sorbent injection system, bag (fabric) filters and carbon adsorbers, after which the purified flue gases are directed through a smoke exhauster into a chimney for dispersion in the atmosphere. After the above-described stages of gas cleaning, the exhaust gases into the atmosphere are safe for humans and the environment in their composition.

The achievement of technical results is also affected by the fact that if there are fats in wastewater in concentrations that are impractical for implementing the technology for producing technical fat or if it is necessary to increase the heat capacity of wastewater sludge, the fats are first separated from wastewater in a flotation unit as flotation sludge with a moisture content of 96-97%. The flotation sludge is sent to the accumulator-averaging tank, to which other fat streams from production processes are also sent. In the accumulator-averaging tank, the concentration of the fat mass from the accumulator-averaging tank is averaged, the fat mass enters the macerator, where coarse impurities are crushed, and from the macerator, the homogeneous fat mass enters through the receiving tank into the liquid waste receiving unit of the rotary incinerator.

Also, the achievement of technical results is affected by the fact that if there are petroleum products in waste water, in concentrations that are inappropriate for the implementation of oil recovery technology or if it is necessary to increase the heat capacity of waste water sludge, they are separated in an oil trap, then the oil sludge is sent to a raw material tank equipped with a heating system, circulation and submersible mixers to prevent sedimentation of suspended matter and caking of sediment, then, according to patent No. 2 8276, the moisture content of the oil sludge is reduced, then it is fed through a receiving tank to the liquid waste receiving unit of the rotary incinerator.

The achievement of technical results is also affected by the fact that if an industrial enterprise has petroleum products as production waste, they are sent to a raw material tank equipped with a heating and circulation system and fed through a receiving tank to a fuel supply unit in the exhaust gas afterburning chamber of a rotary incinerator, which will save fuel to maintain the temperature in the exhaust gas afterburning chamber.

The achievement of technical results is also affected by the fact that, if the wastewater treatment system includes primary settling tanks, acidifiers and other structures designed to separate raw sludge, the raw sludge is combined with excess sludge for joint dehydration and then for joint disposal according to the claimed method.

The achievement of technical results is also affected by the fact that if an industrial enterprise has carbon-containing (organic) waste with a humidity of less than 80%, the said waste is fed directly into the receiving unit of the combustion chamber of a rotary incinerator.

Taking into account the above with the disclosed cause-and-effect relationship between the set of features of the claimed invention and the technical results achieved, it can be stated that the task set as the basis for creating a method for thermal utilization of wastewater sludge in the K-TUO technological complex has been fully solved, since the use of the invention, due to the logically justified sequence of processing stages, makes it possible to ensure the greening of the operation of industrial and municipal wastewater treatment plants by reducing the anthropogenic load on untreated sludge and reducing fuel consumption during the thermal treatment of sludge and industrial waste, which will improve the environmental situation in the territory occupied by wastewater treatment facilities and in the territories adjacent to wastewater treatment facilities, as well as obtaining a product used in urban and road construction, as well as in agriculture.

Fig. 1 shows the process flow diagram for implementing the method of thermal utilization of wastewater sludge in the K-TUO technological complex.

Legend:

1. Receiving tank for excess activated sludge;

2. Excess activated sludge dewatering shop;

3. Receiving container for waste from screens and/or other filtering equipment;

4. Waste crushing and dewatering shop;

5. Bunker for receiving dewatered sludge and waste;

6. Screw dosing pump;

7. Paddle drying plant;

8. Thermal oil boiler;

9. Unit for mechanical cleaning of fumes from the paddle dryer;

10. Gas scrubber (Venturi scrubber);

11. Sewage treatment plants;

12. Fan;

13. Molding apparatus;

14. Screw conveyor for feeding granules from the molding apparatus to the loading unit of the combustion chamber of the rotary incinerator

15. Rotary incinerator;

16. Ash bin;

17. Screw conveyor for hot ash;

18. Cooler;

19. Screw conveyor for transporting cooled products into big bags;

20. Big bag;

21. Gas afterburning chamber;

22. Heat exchange equipment for heating diathermic oil;

23. Chimney system;

24. Dry type gas cleaning unit (GPU);

25. Chimney.

The implementation of the invention is presented in one of the possible variants of its use.

The method is carried out as follows.

Excess activated sludge from the biological treatment facilities for municipal or industrial wastewater is sent to the excess activated sludge receiving tank (1) and then fed to the excess activated sludge dewatering shop (2). Screen waste and/or other filtering equipment is sent to the screen waste receiving tank and/or other filtering equipment (3) and then fed to the waste crushing and dewatering shop (4). Dewatered activated sludge and waste with a moisture content of 72 to 85% are combined in the dewatered sludge receiving bin (5) and fed into the receiving funnel of the dosing screw pump (6) and transported to the vane drying unit (7), in which the sludge is directly dried at a temperature of at least 105°C. The required temperature is created by heat transfer from the heat carrier - diathermic oil heated to 200 - 250°C, which is heated in the thermal boiler room (8) when the technological process is started, and during operation of the technological process is heated in heat exchange equipment (22), the evaporation formed during the drying process from the vane dryer is discharged into the mechanical evaporation cleaning unit (9), and then into the gas washer (Venturi scrubber) (10). The scrubber uses process water circulating in a closed circuit, contaminated water after The gas scrubber (10) is sent to the wastewater treatment plant (11) or to the rotary incinerator through the liquid waste receiving unit (15). The purified vapors leave the scrubber through the fan (12), which serves to create a slight vacuum in the dryer system. The dried sediment with an ash content of 10-30% is fed to the molding unit (13) to form granules of an optimal size for further use of 0.5x0.5 cm. From the molding unit, the granules are sent to the screw conveyor (14), transported to the loading module and sent to the loading unit of the combustion chamber of the rotary incinerator (15). Combustion is carried out at a temperature of 550 ° C to 800 ° C. Then, during the combustion process, the granules are moved to the ash discharge bin (16), the ash is discharged from the ash bin (16) using a hot ash screw conveyor (17) and sent to the cooler (18), from the cooler (18) the cooled ash is transported by a screw conveyor (19) to the big bag loading unit (20). The exhaust gases formed during the combustion of wastewater sludge under the action of vacuum enter the gas afterburning chamber and are burned at a temperature of 850 to 950°C (21). After the afterburning chamber (21), the hot gases are directed through heat exchange equipment (22), in which the diathermic oil is heated to 220 - 250°C, which after heating is directed into a paddle dryer (7), the cooled gases after the heat exchange equipment (22) are directed through a system of chimneys (23) into a dry-type gas cleaning unit (GPU) (24), after which the purified flue gases are directed through a smoke exhauster into a chimney (25) for dispersion in the atmosphere.

Results of the pilot tests

To explain the implementation of the method and prove the solution to the set tasks, we provide an example of the implementation of the declared method of thermal utilization of wastewater sludge in the K-TUO technological complex.

The mixture of excess activated sludge and raw sediment from the primary settling tanks of the Adler municipal wastewater treatment facilities was studied. After dewatering, the moisture content of the sediment was 78%. The dewatered sediment was dried in a paddle dryer. The appearance of the dried sediment formed in the form of granules is shown in Fig. 2. The physical characteristics of the sediment are presented in Table 1. Table 2 shows the elemental composition of the waste.

Table 1 - Physical characteristics of the dried sediment

№p/p Name of the indicator being determined Units of measurement Measurement result 1 Humidity % 10.21 2 Ash content % 19.0 -21.1

Table 2 - Calculated elemental composition of the dried sediment

Name of waste WITH, % H, % O, % N, % S, % Cl, % W, % A, % Q,
kcal/kg Cp, J/(kg×°
WITH) Activated sludge, humidity 20% 29,154 3,665 21,383 0.353 0.088 0,040 20,000 25,357 2585 2,400

Where, C, H, O, N, S, Cl, W, A - the content of carbon, hydrogen, oxygen, nitrogen, sulfur, chlorine in the waste, the moisture content and ash content of the waste;

Q - lower calorific value of waste mixture, kcal/k.

The dried sludge granules were sent for studying the efficiency of combustion processes to the production site of ECO-SPECTRUM LLC in Krasnodar, where a pilot rotary incinerator was installed (Fig. 3).

Fig. 4 shows a diagram of a rotary incinerator installed on an automatic combustion temperature display and control unit. This figure shows the moment in time at which the combustion and afterburning temperature was reached with the burners switched off, due to the released combustion heat.

Fig. 5 shows the combustion process in the internal chamber of a rotary incinerator.

According to the research results, it was established that during the combustion of the sediment, an increase in temperature was observed in the combustion chamber from 500°C to 800°C, and in the gas afterburning chamber from 763°C to 913°C.

At the outlet of the flue gas pipe before the gas cleaning system, the flue gases were poorly visualized, which indicates the optimal degree of loading into the combustion chamber of the rotary incinerator in the amount of 6 kg every 4 hours. With an increase in the amount of loaded sediment, the color of the flue gases changed to a darker color, which made it possible to visually indicate the loading limit of the combustible material into the rotary incinerator.

The appearance of the resulting ash sediment is shown in Fig. 6.

Table 3 presents data on the ash residue analysis.

Table 3 - Ash residue analysis data

№p/p Name
the determined indicator Units of measurement Measurement result 1 Humidity % - 2 Ash content (when burned)
granules 10 mm long) % 96.0 3 pH of aqueous extract pH units 10.2 4 Toxicity index without dilution 99.6 (highly toxic) 5 Toxicity index at 10 times dilution 0 6 Phosphorus oxide (P2O5) % Water-soluble extract 0.003
Acid extract 11.6 7 Aluminum % Water-based extract -
Acid extract -8.1 8 Chlorides % Water-soluble extract 0.0012
Acid extract - 9 Sulfates % Water-soluble extract 0.0590
Acid extract - 10 Sulfur % Water-soluble extract 0.78
Acid extract - 11 Nitrates % Water-soluble extract 0.0071
Acid extract - 12 Potassium % Water-soluble extract 0.070
Acid extract - 13 Sodium % Water-soluble extract 0.718
Acid extract 14 Magnesium % Water-soluble extract 0.067
Acid extract - 15 Calcium % Water-soluble extract 0.304
Acid extract - 16 Manganese % Water-soluble extract 0.000052
Acid eff. -0.03 17 Copper % Water-soluble extract 0.0000009
Acid extract -0.02 18 Nickel % Water-soluble extract 0.000005
Acid extract - 0.02 19 Total iron % Water-soluble extract 0.00005
Acid eff. -0.46 20 Insoluble sediment % Water-based extract -
Acid eff. - 54.87

Analysis of the results in Table 3 indicates the presence of microbiological toxicity due to the high pH value, which allows the ash residue to be added to alkalize acidic soils, used in road construction and landscape correction.

The analysis of the physical ash residue allowed us to establish that when burning large granules 1.0 cm or more in length, fragments of granules containing underburnt sediment were observed in the residue, while with granules 5 mm or less in length, such an effect was not observed. In this connection, it is recommended to form granules no longer than 0.5 cm and no more than 0.5 cm in diameter when forming the sediment. It is also possible to burn the sediment in a loose, non-granulated form.

Claims (6)

1. A method for thermal utilization of wastewater sludge in the K-TUO technological complex, characterized by the fact that first the components of the wastewater sludge are prepared, namely the screen waste is crushed, then dehydrated, the activated sludge is dehydrated, dehydration is carried out using mechanical equipment to a humidity of 72% to 85%, then the dehydrated sewage sludge is sent to a dewatered sludge receiving bin equipped with a ventilation system and screw conveyors installed at the bottom of the bin for mixing the sludge and feeding it into the receiving funnel of a dosing screw pump installed directly under the bin and designed to transport portions of dewatered sludge to a paddle drying unit equipped with two hollow shafts rotating in opposite directions and equipped with special wedge-shaped blades that separate the sludge into separate fractions that come into contact with a hot gas medium having a temperature of at least 105°C, the medium is heated by heat transfer from the coolant through a metal barrier, diathermic oil with a temperature of 200-250°C is used as a coolant, which is prepared depending on the operating conditions of the technology according to two options, the first option involves heating the diathermic oil in a thermal oil boiler house, this option is used when starting the K-TUO technological complex into operation or during periods when the recovered heat from the combustion of the sludge is insufficient for the sludge drying process, according to the second option, the diathermic oil is heated during the continuous operation of the technological complex due to the recovery of thermal energy from the combustion unit, the sludge is dried to a humidity of 10% to 30%, during the drying of the sludge, evaporation is formed consisting of evaporated moisture, heated purge air and the dust fraction of the dried sludge, heated air is supplied into the body of the paddle dryer to remove evaporation, the evaporation moves into the discharge channel through the outlet, and is directed first to dry gas cleaning in the mechanical cleaning unit - inertial cyclones, in which the sedimentation of mechanical impurities from the vapors occurs, and then the vapors are sent for cleaning to the gas scrubber, in which condensation of vapors and wet cleaning from small fractions of dust occur, the scrubber uses industrial water circulating in a closed circuit and fed by a pump to the sprayers, contaminated water after the gas scrubber is sent to sewage treatment facilities or for burning in a rotary incinerator, purified vapors are removed from the scrubber through a special fan, which also serves to create the necessary vacuum in the paddle dryer system, the dried sediment is removed from the paddle dryer through an opening arranged at the end of the paddle dryer, while pouring through a special barrier at the end of the paddle dryer, the dried sediment can be molded into granules measuring 0.5 by 0.5 cm, then the dried granular or loose sewage sludge is sent to a screw conveyor for transportation to the incineration unit, to a rotary incinerator, which consists of two chambers: a combustion chamber and an exhaust gas afterburning chamber, first the dried sewage sludge is fed to the loading module, then dosed using a screw feed system it is sent to the sludge loading unit, from which the dried granular or loose sewage sludge is sent to a screw conveyor for transportation to the combustion chamber of the rotary incinerator, which is a rotating drum, during combustion the sludge moves from the inlet to the outlet of the combustion chamber to the ash bin, while the temperature in the combustion chamber should be maintained from 550 to 800 ° C, when the temperature reaches 650 ° C the burners are automatically switched off, the ash is unloaded from the ash bin using a screw conveyor and sent to the cooler, from which the ash is screw conveyor transports to the big bag loading unit, exhaust gases generated during the incineration of wastewater sludge under the action of the vacuum created by the fan enter the exhaust gas afterburning chamber equipped with its own burner device, where they remain for at least two seconds at a temperature of 800 to 950 °C, when the temperature in the gas afterburning chamber reaches more than 900 °C, the burners of the gas afterburning chamber automatically turn off, after the gas afterburning chamber, the hot gases are directed through a heat exchanger, in which diathermic oil is heated, the cooled gases after the heat exchange equipment enter through a chimney system into a dry-type gas cleaning unit, represented by cyclone filters, a sorbent injection system, bag filters and carbon adsorbers, after which the purified flue gases are directed through a smoke exhauster into a chimney for dispersion in the atmosphere. 2. The method according to item 1, characterized in that, if there are fats in the waste water, the fats are first separated from the waste water in a flotation tank as flotation sludge with a moisture content of 96-97%, which is sent to a storage-averaging tank, to which other fat streams from the production processes of the fat mass are also sent, from the storage-averaging tank the fat mass enters a macerator, in which coarse impurities are crushed, from the macerator the homogeneous fat mass enters through a receiving tank into the liquid waste receiving unit of the rotary incinerator. 3. The method according to item 1, characterized in that if there are petroleum products in the waste water, they are separated in an oil trap, then the oil sludge is sent to a raw material tank equipped with a heating system, circulation and submersible mixers to prevent sedimentation of suspended substances and caking of sediment, then the moisture content of the oil sludge is reduced, then it is fed through a receiving tank to the liquid waste receiving unit of the rotary incinerator. 4. The method according to paragraph 1, characterized in that, if there are petroleum products as production waste at an industrial enterprise, they are sent to a raw material tank equipped with a heating and circulation system and fed through a receiving tank to a fuel supply unit in the exhaust gas afterburning chamber of a rotary incinerator, which will save fuel to maintain the temperature in the exhaust gas afterburning chamber. 5. The method according to item 1, characterized in that if the wastewater treatment system includes primary settling tanks, acidifiers and structures designed to separate raw sludge, the raw sludge is combined with excess sludge for joint dewatering and then for joint disposal according to the claimed method. 6. The method according to paragraph 1, characterized in that if an industrial enterprise has carbon-containing waste with a moisture content of less than 80%, said waste is fed directly into the receiving unit of the combustion chamber of a rotary incinerator.