RU2533801C1 - Device for anaerobic and aerobic treatment of concentrated organic liquids - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: device consists of a vertical sealed housing. In the housing there is a cavity with an anaerobic zone provided with means of gas-dynamic stirring, and a cavity with an aerobic zone provided with gas means of gas-dynamic stirring and aeration, one above the other separated by a horizontal partition. The workspace of the zones is filled with the immobilising and is equipped with pipes for input and output of liquid and discharge of gaseous products with the ability to recycle them. The immobilising cap is made in the form of a combination of hollow vertical rods filled with low-boiling liquid. The outer surface of each of the rods at least in the anaerobic zone is provided with finning.

EFFECT: increasing cleaning efficiency with the possibility of adjusting the degree of removal of contaminants in the anaerobic and aerobic zones depending on the type of liquid, energy security of manufacturing and requirements to depth of cleaning.

2 dwg

Description

The proposed device relates to the field of environmental technology, mainly facilities for the preparation for disposal of bedded manure, litter on farms, livestock, poultry complexes, facilities for the treatment of sediments and other wastes of mechanobiological treatment of household water and industrial wastewater close to them.

In particular, the device can be used in the treatment of centrifuges, supernatants, and filtrates formed by mechanical separation into fractions of bedless manure, litter, sludge and sludge from sewage treatment plants, as well as for the direct treatment of wastewater from the agricultural processing industry.

Known devices for a similar purpose. According to German patent No. 3228782, class CO2F 11/04, a combined apparatus for anaerobic and aerobic treatment of concentrated substrates, is a monoblock design with a coaxial anaerobic zone (outside) and an aerobic aerated zone (inside). The initial concentrated water is subjected to sequential aerobic and anaerobic treatment to obtain biogas and purified stable fluid - an effluent suitable for subsequent deep purification before discharge into the reservoir and / or reuse.

The combination of two processes in one housing significantly reduces capital costs, allows you to effectively use the thermal potential of the aerobic process to maintain the required temperature regime of the anaerobic process.

The main disadvantage of this device is the insignificant retention time of biomass, which leads to its partial premature removal and thereby reduce the specific productivity of the apparatus. Another disadvantage is the presence of a significant radial gradient of the biomass temperature in the anaerobic zone, which leads to a deterioration in the conditions of the heat-sensitive anaerobic process and, as a result, leads to a decrease in the biogas yield and an increase in the load on the aerobic degree, which in turn leads to an increase in energy consumption or a decrease in the quality of treatment .

To a certain extent, these shortcomings were eliminated in A.S. No. 1301790, class CO2F 3/00. In order to increase the length of time the biomass stays in the aerobic and anaerobic zones, coaxial type apparatus provides means for implementing multi-directional biomass movement along a spiral path; while the conditions of internal and external heat and mass transfer are somewhat improved. However, the impossibility of achieving a significant age and concentration of biomass, eliminating the uneven heating of the anaerobic zone does not allow to achieve high processing speeds of the initial substrate.

A common disadvantage of the considered analogues is the impossibility of operating the devices in anaerobic-aerobic processing of substrates.

The closest in technical essence to the proposed invention is a device according to British patent No. 2276617, class. CO2F 3/00.

The prototype device is a vertically oriented apparatus, divided by a horizontal partition into anaerobic and aerobic zones. Each of the zones has outlet nozzles for gases, as well as nozzles for supplying the source and discharge of the treated fluid. The inner cavities of the zones are filled with means of immobilization with anaerobic and aerobic microflora, according to the patent, these means can be granular material, in the pore space of which the gas-liquid flow is moving. Mixing in the anaerobic zone is carried out by biogas. Mixing in the aerobic zone is carried out by an aerating agent - air, oxygen-containing gas, oxygen. At an oxygen concentration of 0.5-5.0 mg / l, a contact time of 5 to 30 minutes and a flow rate in the aerobic zone of 2 to 30 times and a residence time in the anaerobic zone of 8-48 hours, the mass transfer system is “liquid - biomass ( biofilm) - gaseous metabolic products ”is carried out over the entire volume of the apparatus with a fairly high uniformity and speed, which can significantly reduce the volume of the apparatus and carry out its operation in flow mode. Another advantage of the prototype in comparison with analog devices is compactness, relative simplicity of design, the ability to maneuver liquid and gas flows, as well as the creation of multi-body (from 2 to 30) units based on a unified aerobic-anaerobic module. The device can operate both anaerobic-aerobic and aerobic-anaerobic modes. The size range indicated in the patent has a height of 2-30 m and a diameter of 1-20 m.

The main disadvantage of the prototype device are:

- insufficient uniformity (uniformity) of the temperature field in the anaerobic zone, which can cause a decrease in the intensity of anaerobic fermentation during temperature fluctuations of the original liquid and / or environment;

- the need for special design solutions for loading and unloading immobilizing material (unloading hatches, hydraulic locks), the duration and complexity of these procedures.

The task of the invention is to remedy these disadvantages.

By introducing a unified structural element - a two-phase thermosiphon, the necessary temperature stability of the anaerobic process is achieved. In this case, the biological heat generated during the introduction of the conjugated aerobic process is useful. The main problem that arises during the operation of surface heat-exchange elements, namely, pollution of the heat exchange surface by organic deposits, is eliminated in this case due to the effect of surface bioregeneration due to the metabolic activity of the corresponding groups of bacteria using organic pollution as food. The required surface of heat and mass transfer is achieved by introducing longitudinal finning with characteristics determined by operational (critical speed) and structural (manufacturing technology) limitations.

The actual specific surface immobilization may be 50-100 m ² / m ³ or more. The layout solution in the form of a single assembly of thermosiphons with a dividing wall allows for quick installation of the structure, as well as its removal from the device.

, при этом возможен выход температуры процесса из «эффективного» диапазона и, как следствие, снижение выхода биогаза и степени очистки потока. В то же время, в аэробной зоне прототипа температура возрастает на значение $$\Delta {Т}_{аэ}^{био}пр$$

за счет выделения биологического тепла, при этом тепловая энергия бесполезно теряется с эффлюентом. При использовании заявляемого технического решения, за счет подведения тепловой энергии изотермическим тепловодом выходная температура потока в анаэробной зоне возрастает на величину $$\Delta {Т}_{ан}^{вых}пр$$

, соответственно, температура на выходе из аэробной зоны снижается на $$\Delta {Т}_{ан}^{вых}пр$$

. Таким образом, снижаются бесполезные потери в окружающую среду, повышаются степень очистки потока и и выход товарного биогаза.The figure 2 presents the temperature course of the working medium (processed fluid, substrate) along the heat and mass transfer surface of the device for anaerobic-aerobic treatment of concentrated organic liquids. In the absence of isothermal ducts in the unheated space of the anaerobic zone due to heat removal to the environment, the temperature decreases by $$\Delta T_{\mathrm{but}n}^{P\mathrm{about}t}PR$$

At the same time, the process temperature may leave the “effective” range and, as a consequence, decrease the biogas yield and the degree of stream purification. At the same time, in the aerobic zone of the prototype, the temperature increases by a value $$\Delta T_{\mathrm{but}\mathrm{uh}}^{b\mathrm{and}\mathrm{about}}PR$$

due to the release of biological heat, while thermal energy is uselessly lost with the effluent. When using the claimed technical solution, due to the supply of thermal energy by an isothermal heat sink, the output temperature of the flow in the anaerobic zone increases by $$\Delta T_{\mathrm{but}n}^{\mathrm{at}sx}PR$$

accordingly, the temperature at the exit from the aerobic zone decreases by $$\Delta T_{\mathrm{but}n}^{\mathrm{at}sx}PR$$

. Thus, useless losses to the environment are reduced, the degree of purification of the stream and the yield of commercial biogas are increased.

The operability of the structures “heat transfer surface - immobilizing surface” is confirmed by a number of works. So, in the study “The performance of a heat exchanger type anaerobic biofilm reactor” by Escalera CR, Uchida S. Water Science technology, V.24, No. 5, it was found that at the wall temperature of the heat exchanger - anaerobic bioreactor 25-37 ° C and at a temperature of the feed stream of 5-15 ° C, the efficiency of removing organic contaminants is 70-98%.

The technical result is achieved by the fact that the device for anaerobic and aerobic treatment of concentrated organic liquids consists of a vertical casing, in which cavities separated by a horizontal partition are placed with an anaerobic zone equipped with gas-dynamic mixing means, an aerobic zone equipped with gas-dynamic mixing and aeration tools. The working space of the zones is filled with an immobilizing nozzle and equipped with nozzles for introducing and discharging liquid and venting gaseous products with the possibility of their recirculation. The immobilizing nozzle is made in the form of a set of bare vertical rods filled with boiling liquid, and the outer surface of the rods, at least in the anaerobic zone, is equipped with fins.

The basic structural and technological scheme of the device for anaerobic and aerobic treatment of concentrated organic liquids is presented in figure 1. The apparatus consists of a vertical sealed housing 1, equipped with a cover 2 and a partition 3. The partition 3 divides the housing 1 into anaerobic 4 and aerobic 5 zones. The anaerobic zone 4 is equipped with nozzles 6 and 7 for supplying and discharging liquid and a nozzle 8 for biogas removal. The aerobic zone 5 is equipped with pipes 9 and 10 for supplying and discharging fluid and a pipe 11 for discharging gaseous metabolic products. Vertically oriented heat and mass transfer elements are placed inside the aerobic and anaerobic zones - thermosyphons 12, combined by means of a partition 3 and fastening elements into a single easily removable assembly 13. Each thermosyphon, at least in anaerobic zone 4, is equipped with outer ribs 14 of a vertical type. A low-boiling liquid, for example freon, is provided inside the sealed cavity of the thermosiphon 12, which, when condensed by evaporation, forms a film 15. In turn, a biofilm is formed on the surface of the ribs 14 and thermosiphon tubes 12, which, when entering into biodynamic exchange with the medium being cleaned, absorbs organic and mineral components, oxygen (in the aerobic zone) and releases metabolic products into it - biogas (in the anaerobic zone), carbon dioxide (in the aerobic zone), excess biomass. Part of the active microflora is located in free space and also takes an active part in mass transfer processes. The aerobic zone 5 is equipped with aeration means 17. It is contemplated to maneuver the fluid streams through the distributor 18. If necessary, the apparatus is equipped with additional means of preliminary processing of the substrate, for example, aerobic, anoxide or anaerobic hydrolysis reactors 19, mechanical thickeners 20. The anaerobic unit is equipped with a gas storage 21 and a compressor 22. The aerobic unit is equipped with a blower 23. Biogas for mixing is fed into the gas distribution device 24. Outdoor ited apparatus is provided with a thermal insulation 25.

In anaerobic-aerobic mode, the device operates as follows. The initial wastewater generated after processing the substrate, for example, bedding manure, in the hydrolysis reactor 19 and the mechanical thickener 20 enters the anaerobic zone 4 of the sealed housing 1 through the pipe 6 and interacts with the biofilm located on the surface of the ribs 14 and the thermosyphon 12 body. As a result of biochemical reactions, the liquid is purified from organic contaminants, the main part of which (up to 90%) goes into biogas discharged through pipe 8 and a biofilm (not more than 3%), which, upon reaching certain age is torn away from the surface, taken out from the purified liquid and is separated by gravitational means. The fluid flow is distributed along the surface of the assembly 13 in such a way as to ensure uniform contact of the fluid with the biofilm. Biogas accumulates in the upper part of the apparatus under cover 2. When processing the substrate with a moisture content of less than 99%, biogas is supplied to the anaerobic zone 4 through the gas distribution device 24 by the compressor 22 from the gas storage 21. A partially purified liquid or an additional stream of the initial waste liquid is sent to the aerobic zone 5 of building 1 , separated by a partition 3 from the anaerobic zone 4, through a switchgear 18 and a pipe 9. Processing is carried out with activated sludge and partially aerobic biofilm. The bulk of the contaminants passes into aerobic biomass, which is partially carried out with the purified liquid into the gravity separation apparatus of a known design (not shown in the diagram). Aerobic conditions are created by means of aeration 17, for example, a filter plate of a known type. Gaseous metabolic products are discharged through pipe 11.

Thermal energy released during aerobic biochemical reactions is transmitted through the surface of the thermosyphon 12 to a low-boiling liquid, which, under the action of gravity, flows from the upper (condensation) zone of the apparatus in the form of a film 15. As a result of heat supply, the liquid boils, the formed vapors with low density enter the condensation zone, where heat is transferred to anaerobic biomass (biofilm) 16. Condensate formed during heat and mass transfer flows into the lower (evaporation) zone, and then the process is repeated. The distribution device 18 provides for the recirculation of aerobic and anaerobic flows, as well as, if necessary, transferring the operating mode of the device from anaerobic-aerobic to aerobic-anaerobic mode.

The proposed device allows you to process liquids (centrifuges, filtrates, non-precipitating liquids) with a high concentration of organic pollutants (up to 5-60 g / l COD) and a cleaning efficiency (COD) of more than 90%, moreover, the degree of contamination removal in anaerobic and aerobic zones can be adjusted depending on the type of liquid, energy supply of production and requirements for the depth of cleaning.

During maintenance, the lid 2 of the apparatus is removed and the assembly 13 can be removed from the housings 1 by means of known lifting means.

Claims (1)

 A device for anaerobic and aerobic treatment of concentrated organic liquids, consisting of a vertical sealed enclosure, in which cavities separated by a horizontal partition are provided with an anaerobic zone equipped with gas-dynamic mixing means, an aerobic zone equipped with gas-dynamic mixing and aeration tools, and the working space of the zones is filled with an immobilizing nozzle and equipped with nozzles for input and output of liquid and removal of gaseous products with the possibility of their re circulation, characterized in that the immobilizing nozzle is made in the form of a set of hollow vertical rods filled with boiling liquid, and the outer surface of the rods, at least in the anaerobic zone, is equipped with finning.

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