RU38756U1 - DEVICE FOR BIOLOGICAL SEWAGE TREATMENT - Google Patents

Abstract

The utility model relates to environmental protection and can be used in utilities and other industries for new construction and reconstruction of existing treatment facilities. Wastewater is fed into a bioreactor containing anaerobic and aerobic zones, together with a mixture of suspended activated sludge and freely floating nozzles for attaching activated sludge microorganisms to their surface. A controlled air is introduced into the bioreactor to produce anaerobic and aerobic zones with a dissimilar oxygen concentration medium. In the anaerobic zone, the sludge mixture is brought into circulation by mechanical or pneumatic action. In the aerobic zone, the mixture is divided into two streams, one of which is returned to mixing with the source wastewater. Another stream is sent to a sludge separator for preliminary clarification to obtain a compacted activated sludge returned to the aerobic zone, and a mixture of excess sludge and biologically treated wastewater. The reservoir is divided by longitudinal and transverse partitions with the formation of an aerobic zone with an aeration system and anaerobic zone. Partitions in the anaerobic zone form a closed labyrinth. At the end of the corridors of the labyrinth, guiding partitions of an arcuate shape are installed. The aerobic zone occupies from 1/2 to 3/4 of the volume of the tank, preferably from 2/3 to 3/4 of the volume. The utility model allows to increase the degree of wastewater treatment from suspended solids, as well as from organic compounds, ammonium compounds and phosphorus. Excluded conditions for increasing the concentration of metabolic products.

Description

The utility model relates to environmental protection and can be used in utilities and other industries for new construction and reconstruction of existing treatment facilities.

A device for biological wastewater treatment, disclosed in the certificate for utility model RU No. 404 U, MPK7 C 02 F 3/02, 05/16/1995, which is taken as a prototype of the proposed device, containing a tank with a water supply and drainage trays, divided by partitions into two and more longitudinal corridors equipped with an aeration system and which are cleaning steps. The tank is divided by a transverse partition with the formation of a transverse corridor serving as a regenerator-compactor of recirculated activated sludge. All corridors are divided by inclined, not reaching the bottom partitions, equipped with windows with flow-visors and forming aeration and sludge zones in the corridors. A bubbler is installed under the partitions, the aeration zones of the cleaning steps are equipped with fixed and floating nozzles for attaching microflora, and the sludge separation zones are equipped with thin-layer modules. Longitudinal vertical partitions are provided with windows for partially cleansed and clarified wastewater to enter the next stage of purification, the transverse partition is equipped with sludge discharge windows located above the water level in the treatment steps, the sludge separation zone of the regenerator-seal is equipped with a sludge collection tray and airlift for pumping compacted sludge to the water supply the tray, and the aeration zones of the cleaning steps are equipped with an airlift for pumping sludge mixture into the regenerator-compactor.

The disadvantages of this device are: the lack of the ability to maintain activated sludge and freely floating self-generating

suspended nozzles and active mass transfer, as well as the susceptibility of filters to clogging during the accidental interruption of air supply to the aeration system.

The objective of the utility model is to increase the degree of wastewater treatment from suspended solids, as well as from organic compounds, ammonium compounds and phosphorus. The solution to this problem provides a technical result, which consists in eliminating the conditions for increasing the concentration of metabolic products, as well as achieving a concentration of activated sludge in the aerated liquid of more than 12 g / l and increasing its age over 18 days.

The specified technical result is ensured due to the fact that in the biological wastewater treatment device containing a reservoir with water supply and drainage trays loaded with freely floating nozzles, separated by partitions with the formation of an aerobic zone with an aeration system, a means for hydraulically protecting the filters from clogging, a sludge separator equipped with a partition that does not reach the bottom of the tank with windows and stream-visors, in contrast to the prototype, an anaerobic zone formed by the moles located to receive the corridors forming a closed channel, the device is equipped with a means for mechanical or pneumatic impact on the passing stream of treated wastewater with a mixture of suspended activated sludge and freely floating nozzles to ensure their circulation through the closed channel (labyrinth), while at the end of the corridors it is desirable for the labyrinth to install guiding partitions having an arched shape. The aerobic zone occupies from 1/2 to 3/4 of the volume of the tank, preferably from 2/3 to 3/4 of the volume. The aeration system is installed under the baffle plate. The device is equipped with a means for hydraulic protection of the filters from clogging, made in the form of a riser, the water level in which is higher than the water level in the tank. Means for mechanical or

pneumatic effects on the passing stream are installed in the anaerobic zone.

Figure 1 shows a device for deep biological wastewater treatment, plan view. Figure 2 is a section through 1-1 in figure 1. Figure 3 - the proposed device, a top view. Figure 4 (a-g) - various embodiments of the device.

A device for deep biological wastewater treatment includes a tank 1 with a water supply tray 2 and a water discharge tray 3. The tank 1 is loaded with self-generating self-generating nozzles 4 for attaching activated sludge microorganisms, has an anaerobic zone 5 and aerobic zone 6. In the anaerobic zone 5, the reservoir is divided by longitudinal partitions 7 into corridors 8 of various widths with the possibility of fluid circulation through a closed channel (labyrinth). The anaerobic zone 5 is equipped with pneumatic or mechanical pulsators 9. The extreme longitudinal partitions 7 are connected by a transverse partition 10, forming a U-shaped corridor, which houses at least two corridors 8. In the gaps between the partitions, flow guiding arc partitions are installed 11. The desilter 15 is formed of an inclined, non the septum 16 reaching the bottom is provided with windows 17 with jet guards. The aerobic zone 6 is located in the corridor adjacent to the sludge separator 15 and is equipped with an aeration system 12 installed under the sludge separator wall, a means 13 in the form of a riser, the water level in which is above the water level in the tank, to hydraulically protect the filters 14 from clogging.

This device can serve as a unified element for the reconstruction of existing aeration tanks for the implementation of the proposed method.

Figure 4 (a-d) schematically shows embodiments of a device with a different number of corridors forming a closed labyrinth.

The device operates as follows.

The source wastewater is fed into the tank 1 through the feed tray 2 and mixed with a sludge mixture in which the concentration of activated sludge in the dry matter is at least 2.5 g / l, and freely floating self-generating nozzles 4 for attaching activated sludge microorganisms to their surface and the mixture is brought into circulation in a closed labyrinth with a speed of at least 0.15 m / s under the influence of a pneumatic or mechanical pulsator 9 installed in the anaerobic zone 5. In the aerobic zone 6, which takes from 1/2 to 3/4 of the volume of the reservoir, the sludge mixture is divided into two streams, one of which is returned to mixing with the source wastewater in the anaerobic zone 5, and the other is sent to the sludge separator 15, where preliminary clarification is performed to obtain compacted activated sludge with free-floating nozzles and a mixture of excess sludge and biologically purified wastewater, which, after final clarification, is discharged through the drainage tray 3. Sealed activated sludge with self-generating self-generating nozzles 4 through the windows 17 with flow-directing and peaks under the influence of the rising water-air flow at the boundary, not reaching to the bottom of the partition 16, is recycled to the aerobic zone 6 and is mixed with the circulating flow to continue movement.

The guide walls installed at the beginning and at the end of the corridors 8, which have an arc-shaped shape, reduce the pressure loss of the flow and ensure its smooth rotation.

When the air supply to the aeration system 12 is stopped, clean water fills it from the inside, located in the riser of the hydraulic protection device 13, thereby preventing the penetration of the silt mixture through the filters 14.

In one of the preferred embodiments of the utility model, 2/3 to 3/4 of the reservoir volume is allocated for the aerobic zone.

The concentration of dissolved oxygen in the anaerobic zone is not higher than 0.4 mg / L, and the aerobic zone varies from 0.5 mg / L at the border with the aerobic zone to 4.2 mg / L in the middle and up to 5 mg / L at the end.

Freely floating nozzles are self-generating and are particles of polymer that protect the biofilm from abrasion.

The advantage of the proposed utility model is that it allows repeatedly changing the environment of attached and freely floating microorganisms in one technological tank with a period of stay in these environments for any technologically necessary time (from several minutes to several hours) depending on the quality and quantity of contaminants . The alternate stay of the treated water in the aerobic and anaerobic zones, the use of free-floating nozzles for attaching activated sludge microorganisms to their surface allows the conditions to increase the concentration of metabolic products to be eliminated, in addition, the separation and return of suspended activated sludge and free-floating nozzles ensures the concentration of activated sludge in the aerated liquid more than 12 g / l and an increase in his age over 18 days.

Thanks to the proposed utility model, zones are formed in the reservoir in which the medium is heterogeneous in terms of dissolved oxygen.

Moreover, in the aerobic stage, nitrification mainly occurs using dissolved oxygen and chemically bound in the form of nitrate formed after nitrification of ammonium compounds.

In the anaerobic stage, an oxygen-depleted medium formed far from the aeration zone, denitrification mainly occurs using chemically bound oxygen and the biological removal of phosphorus.

The proposed utility model allows this process to be carried out in one technological tank in conjunction with the removal of organic contaminants. At the same time, there is no need to return biologically treated wastewater to the cycle, the amount of which in most cases is many times greater than the amount of wastewater treated in the classical scheme.

Compared with the known, the proposed utility model is characterized by the stability of the processes with special simplicity and lower costs.

An environment with heterogeneous conditions required for individual processes to occur is created, according to a utility model, simultaneously in one technological vessel by circulating contents at a speed of at least 0.15 m / s in the anaerobic stage.

Example. Source wastewater with the composition of pollution:

chemical oxygen demand (COD) 570 mg / l, biological oxygen consumption (BOD ₅ ) - 200 mg / l, NH ₄ - 31 mg / l, PO ₄ - 15.3 mg / l, NO ₂ - 0.02 mg / l, MO ₃ - 1.53 mg / l is subjected to treatment under the conditions of the known and proposed method with an aeration time of 7 hours.

The table shows the comparative results of the known and proposed devices.

Table Indicator Known device Suggested device COD, mg / l 45 31 BOD ₃ , mg / l 6 3 NH ₄ , MG / L 3 5.3 NO ₂ , mg / l 0.014 0.017 NO ₃ , mg / l 5.1 4.3 Power consumption for

unit of organic pollutants removed, kWh 3.5 1.2

As can be seen from the table, the indicator of energy consumption per unit removed organic pollution in the proposed device is more than 2 times lower than the same indicator of the known device.

Claims (6)

1. A device for biological wastewater treatment, containing a reservoir separated by at least one partition to form an aerobic zone with an aeration system, and a sludge separator, characterized in that at least one partition is located with receiving corridors forming a closed channel , part of which adjacent to the sludge separator, forms an aerobic zone, and the rest forms an anaerobic zone, and the device is equipped with a means for influencing the passing stream of treated wastewater with a mixture of suspended active of sludge and floating freely baits for their circulation along the closed channel. 2. The device according to claim 1, characterized in that at the end of the corridors of the closed channel guide baffles having an arcuate shape are installed. 3. The device according to claim 1, characterized in that the aerobic zone occupies from 1/2 to 3/4 of the volume of the tank, preferably from 2/3 to 3/4 of the volume. 4. The device according to claim 1, characterized in that the aeration system is installed under the sludge separator wall. 5. The device according to claim 1, characterized in that it is equipped with a means for hydraulic protection, made in the form of a riser, the water level in which is above the water level in the tank. 6. The device according to claim 1, characterized in that the means for mechanical or pneumatic impact on the passing stream is installed in the anaerobic zone.