SK6212001A3 - Multi-stage biological waste water purification method with interrupted operation and device for carrying out this method - Google Patents

Abstract

The method is carried out in a device formed at least two pre-purification reactors, a purification reactor and an internal air recirculation circuit connected to at least one source of pressurized air. his the essence is that depending on the time chosen the intervals or the amount of flowing water according to pre-set parameters in each of the pre-cleaning reactor controlled self-contained cleaning process from aeration of purified water and selected combination cleaning phases formed by stirring the purified water and sludge settling, while providing pre-pumping pre-treated water to the purification reactor when in the purification reactor At the same time, a complex purification process formed by the reactor takes place agitation and aeration of purified water and settling sludge, while purging cleaned water, recirculating the sludge back to each or one of the pre-purification reactors and with occasional pumping excess sludge outside the device when starting or terminating the individual stages of the purification processes in pre-purification reactors or in a purification reactor is initiated on the basis of level variation evaluation in a cleaning reactor using float switches.

Description

Method of multi-stage biological waste water treatment with intermittent operation and apparatus for carrying out this method

Technical field

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for the multi-stage biological treatment of waste water with intermittent operation using an activated sludge activation system in a laying operation,

sewage from small local residential buildings or restaurants and hotel operations.

BACKGROUND OF THE INVENTION

Methods and devices for biological treatment of waste water are known, for example according to CZ PAT 285144 or WO 99/55628, which solve a purification process taking place with a continuous inflow of purified water. In this process, a phase of the purification process takes place in each zone of the plant, from coarse pre-treatment through activation in the oxide and anoxide zones to separation and settling of impurities as the entire volume of purified water is gradually pumped from zone to zone. The disadvantage of these waste water treatment plants is their relatively high energy and economic demands of operation, when the demands are placed on operation and maintenance in terms of monitoring of floating impurities and concentration of activated sludge, which has to be pumped out if exceeded permitted concentration, otherwise into the outflow of purified water.

Further, there are known solutions for biological treatment of waste water with a discontinuous flow of purified water, for example according to the patents CZ 282411, WO 96/16908 and CZ 284697, in which the activation level is interrupted after reaching the maximum level in the activation tank or process and the excess sludge and purified water are drained from the activation tank. This method of intermittent cleaning in two separate functional tanks has

The disadvantage is that, in the case of the contaminated waste water inlets, it is very soon to be pumped incompletely into the activation tank during the short-term activation process and can therefore also be discharged. A major problem with these devices is also the fact that contaminated water, which entered the pump interior during the activation phase of the purification, also reaches the drain during the first stages of pumping the purified water. Since the excess sludge is pumped out only a few times a year, the accumulation of this sludge in the system causes a drop in oxygen levels and backwater contamination, in particular by phosphorus. A further disadvantage of these solutions is that the devices are equipped with multiple electronic controls, such as solenoid valves and complicated interconnected control processors, which increases the likelihood of malfunction and shutdown of the plant.

There are also known solutions of wastewater treatment with discontinuous flow according to CZ PAT 287852 or CZ UV 4800 in a pair of separate reactors, where according to the filling and emptying of individual reactors, individual phases of activation are continuously shortened or extended. The disadvantage of these solutions is that when the cleaning process is carried out in a single reactor, sludge is formed, the properties of which are adapted to a particular type of polluted waste water. After the reactor is drained and after the introduction of new contaminated water of other properties, the sludge must be adapted for a certain time, thus deteriorating the purification process parameters. After the purified water is discharged, a large concentration of sludge remains in the reactor to which new waste water is gradually admitted, resulting in an unevenness in the biological parameters of the purification process. A further disadvantage of these solutions is the unevenness and impact rate of the effluent from the plant.

It is also known to design a wastewater treatment plant with operation in part discontinuous and part continuous according to CZ UV 9904, whose disadvantage is the high structural complexity of the device and its control and control elements.

SUMMARY OF THE INVENTION

The above-mentioned deficiencies are largely eliminated by the multi-stage method

- 3 intermittent biological treatment of wastewater in a plant consisting of at least two pre-treatment reactors, a purification reactor and an internal air recirculation circuit connected to at least one compressed air source, which, depending on the time intervals or amount of effluent flowed, pre-set parameters in each of the pre-treatment reactors controlled by a separate purification process consisting of aeration of the purified water and a selected combination of purification phases consisting of mixing the purified water and settling sludge while ensuring pre-pumping of pre-purified water into the purification reactor. mixing and aeration of purified water and settling of sludge while ensuring pumping of purified water, recirculation of return sludge back to each or any of predčisťovacích reactors and occasionally pumping excess sludge out of the device when the commencement or completion of the various stages of purification processes in predčisťovacích reactors or reactor cleaning is initiated by evaluating fluctuations in blood purification reactor using float switches.

It is a further object of the invention that upon stopping the waste water flow to the plant, pressurized air is fed intermittently to the main aerators of the pretreatment reactors and the purification reactor, by adjusting the different timing levels, thereby mixing or aerating the water without draining the purified water.

It is also an object of the invention that when the level in the activation reactor is raised above the maximum level, the supply of pressurized air from the source to the purification reactor or to all reactors is stopped first and after a certain period of time necessary to ensure the settling phase. at the end of which the operation of the device is switched back to the normal mode, in which all the cleaning phases are carried out successively.

The design of the apparatus for carrying out the process according to the invention is that the interconnected pre-treatment reactors are completely separated from the purification reactor with which the last of the pre-treatment reactors is connected by the first control reactor.

- a 4 mammoth pump connected to the first air float valve, wherein a coarse dirt trap is located at the waste water inlet of the first pre-treatment reactor, the activation reactor being equipped with a second pilot mammoth pump for evacuating pure water connected to the second float valve a return sludge pump connected to each of the pre-treatment reactors and a mammoth pump of excess sludge.

It is a further object of the invention that a mammoth excess sludge pump is led through an aerobic excess sludge stabilizer to a sludge tank which is connected to one of the pretreatment reactors to allow the sludge water to flow back into the purification process and that the apparatus comprises a purification stage into which the other a control mammoth pump and which is equipped with a clean water outlet and a second mammoth pump of the return sludge leading to the first pretreatment reactor.

It is also an object of the invention that all of the mammoth pumps and aerators of the purification stage reactors and the excess sludge stabilizer are connected to the source of compressed air via a first control element or a second control element.

It is advantageous here that the main reactor aerators, the first air float armature and the first mammoth return sludge pump are connected to one branch of the ciculation air circuit coming from the first regulating element, and the auxiliary aerators of the pre-purification reactors are connected to the second branch through the second float. the second control mammoth pump and the second mammoth return sludge pump; and secondly the second auxiliary aerator of the excess sludge stabilizer, wherein the second regulating element, which is connected in parallel to the second branch of the first regulating element, is connected with the mammoth sludge pump and the auxiliary aerator of the purification stage.

In an optimum embodiment, the purification reactor is provided with a first through hole for passing the activated sludge foam into the last pre-treatment reactor, and the post-cleaning stage is equipped with a second through opening for passing the activated sludge foam into the first pre-treatment reactor, wherein

- 5 cleaning stage is equipped with disinfectant dispenser.

According to the invention, a new and higher effect is achieved in that the purification process combines the effects of continuous and discontinuous wastewater flow through the purification device. The purification process takes place automatically and evenly in each of the series reactors connected separately with continuous recirculation of the sludge between the individual reactors. The decomposition of the purification process into stages, where in each of the reactors a certain kind of bacteria dominates the purification, results in a complex purification effect with obtaining water of high purity quality. The device for carrying out the method according to the invention is relatively simple in construction, it is equipped with a small number of simple operating elements, which simplify operation and maintenance as well as reduce the possibility of failure and interruption of the plant operation. The device also allows economical and energy-efficient operation with automatic control of the choice of cleaning modes according to the amount of waste contaminated water inflow.

BRIEF DESCRIPTION OF THE DRAWINGS

A particular example of the construction of the device according to the invention is schematically shown in the accompanying drawings, in which FIG. 1 shows, in principle, a block diagram of the apparatus showing the interconnection of the individual components of the apparatus by means of an internal circulation circuit, FIG. 2 shows a plan view of the device, FIG. 3 shows a vertical section of the device of FIG. 2 in the line A-A of FIG. 4 shows a vertical section through the device of FIG. 2 in the plane B-B and in FIG. 5 an alternative block diagram of the plant for large waste water treatment plants.

DETAILED DESCRIPTION OF THE INVENTION

The multi-stage wastewater treatment plant consists of two interconnected pre-treatment reactors 2, a purification reactor 3 and a post-purification stage 4, for example a settling tank, which are arranged in a common cylindrical casing 5, as shown in FIG. Pre-purification reactors 2

6 are completely separated from the purification reactor 3 when the first pre-purification reactor 21 is connected to the waste water inlet 6 and is equipped with a coarse dirt trap 1 and a second pre-purification reactor 22 is connected to the purification reactor 3 by a first pilot mammoth pump 7 connected to the first air float armature

The purification reactor 3 is connected to the degassing space 41 of the purification stage 4 by a second control mammoth pump 9 connected to a second air float armature 10, and is equipped with a mammoth pump 11 of excess sludge, which is led through the aerobic stabilizer 12 of excess sludge 13 above the second pretreatment reactor 22. The purification reactor 3 is also provided with a first mammoth return sludge pump 14 which opens into both pretreatment reactors 2 through a first discharge opening 18 for passing the activated sludge foam into the second pretreatment reactor 22 and the first float switch 35 and second float switch. 36 to allow the operation modes of the device to be switched to economy or extreme. The purification stage 4 is provided with a purified water outlet 15, a disinfectant dispenser 16, a second mammoth return sludge pump 17 which opens into a first pre-treatment reactor 21 and a second through-opening 19 for sludge activation of the activated sludge, also into the first pre-treatment reactor 21.

All components 2, 3 and 4 are connected to a common compressed air source 31, such as a compressor, to which the air float fittings 8 and 10 are connected, as well as all the mammoth pumps 7, 7, 14, 17 wherein a first control element 32, for example a three-way solenoid valve, for controlling the flow of purified water and a second control element 33, for example a one-way solenoid valve, for controlling excess sludge evacuation is connected to the air circulation circuit. Main aerators 301 of the pre-purification reactors 2 and the purification reactor 3 are connected in series to the first manifold 321 from the normally open normally-open control element 32 and simultaneously the first pilot mammoth pump 7 and the mammoth return sludge pump 14 are connected via the first air float armature 8. Auxiliary aerators 302 of the pretreatment reactors 2 are connected in series to the second manifold branch 322 of the normally closed normally closed control element 32, and secondly through the second air float armature 10 the second control mammoth pump 9

7 with a second mammoth sludge pump 17 and on the other hand an aerobic excess sludge stabilizer 12 equipped with a second auxiliary aerator 304. The second regulating element 33, connected in parallel to the second air distribution branch 322, is connected in parallel with the first auxiliary aerator 303 and the purification stage 4. pump 11 of excess sludge. The entire device is provided with a control device (not shown), for example a computer, which is connected to a power source.

In the purification process, the contaminated waste water flows through the inlet 6 through the coarse dirt trap 1 to the first pre-treatment reactor 21, where the first return sludge pump 14 also feeds the first part of the return sludge from the purification reactor 3. The partially purified waste water flows into the second pre-treatment reactor 22 in which further purification phases take place, when the return sludge as well as the second part of the return sludge from the purification reactor 3 are also fed into it via the first mammoth pump 14. Further, the purified water is pumped by the first pilot mammoth pump 7 to purification reactor 3 for further purification phases. At the same time, the first control mammoth pump 7 creates a first accumulation space for a possible waste water inflow from both pre-treatment reactors 2. From the cleaning reactor 3, after a certain period of time necessary for settling, for example 20-30 minutes, purified water is pumped by the second control mammoth pump 9 into the degassing space 41 of the purification stage 4, wherein the second control mammoth pump 9 creates a second storage space for the waste water inflow from the pre-treatment reactors 2. In the purification stage 4 fine sludge particles are deposited on its walls which are entrained by the auxiliary aerator 303 and subsequently The second mammoth pump 17 returns the sludge pumped back to the first pre-treatment reactor 21. The purified water then flows from the upper zone of the purification stage 4 through the outlet 15 out of the treatment plant to a recipient (not shown) as needed. disinfectants are automatically added from the dispenser 16 thereto. The partially stabilized excess sludge is discharged in the automatic mode from the purification reactor 3 by means of a mammoth pump 11 of excess sludge via a stabilizer 12 into the sludge bed 13, which can also be realized in the form of a drainage collecting bag.

- 8 If the waste water does not enter the plant within the specified time, the controller will switch it to a power saving mode that ensures that the activated sludge is kept in good condition without the need for a long-term wastewater inflow, significantly reducing power consumption to operate the plant.

The individual cleaning phases of the intermittent plant inspection, where the mixing, aeration and possibly settling phases are carried out in the pre-treatment reactors 2, and the cleaning reactor 3 of the mixing, aeration, settling, clear water and excess sludge pumping phases can be described based on of compressed air and the first control element 32 and the second control element 33 connected thereto by means of the following table:

Phase number 1 2 3 4 5 Source 31 interrupt, on turned on turned off turned on turned on element 32 turned off turned off turned off turned on turned on element 33 turned off turned off turned off turned off turned on

Phase # 1 - mix:

This cleaning phase takes place in the intermittent supply of air from the compressed air source 31 with the first control element 32 open, when this air is fed to the main aerators 301 of the pre-purification reactors 2 and the purification reactor 3 and simultaneously through the first air float armature 8 to the first pilot mammoth pump 7 and to the first mammoth pump 14 of the return sludge. The second mammoth pump 9 is disconnected so that no sludge water is pumped from the activation reactor 3.

- 9 Phase no. 2 - aeration:

This cleaning phase proceeds in the same way as the previous phase except that compressed air is continuously supplied from the source 31.

Phase # 3 - settling:

Settling occurs when the compressed air supply from the source 31 is interrupted when all the aerators 301, 302 and 303 and all the mammoth pumps 7, 9, 11 are present. 14 and 17 not working.

Phase # 4 - pumping of purified water:

This cleaning phase takes place when the first control element 32 is switched to the second position, when the secondary aerators 302 in both pre-treatment reactors 2 are actuated, and at the same time the second control mammoth pump 9 and the second mammoth pump are switched on via the second air float armature. The purified water then flows through the effluent 15 from the purification stage 4. After the level of the inactivation reactor 3 has fallen below the specified minimum, the second air float valve 10 closes the air supply to the second control mammoth pump 9 and thereby. pumping of purified water is immediately stopped, but due to the setting of the parameters of the control automat the operation of other functional elements finishes to the end of the selected time interval.

Phase # 5 - pumping off excess sludge:

This phase begins at the same time as purging the purified water with occasional switching on of the second control element 33, depending on its setting in the control machine.

- 10 Power saving mode:

If the level in the purification reactor 3 drops below the minimum set value, the first float switch 35 is switched on and only the aeration and settling alternately takes place in the apparatus for a certain period of time, depending on the setting of the controller. The previously described economical cleaning phases no. 2 and no. 3 or phase no. 1. Setting the time intervals for the power saving mode can be carried out in several levels according to the time of non-leakage of the new waste water, for example from 1 hour to 24 hours, and hence the power saving mode can take place in several levels.

Operation of the device in the case of a surge inflow of waste water:

In a sewage inflow, when the second control mammoth pump 9 is not able to drain the water from the purification reactor 3, the control reactor raises the level above the maximum level set for the second float switch 36, which immediately ensures the device is switched to extreme operation. In this mode, the compressed air source 31 is switched off first, and all of the reactors 41, 22 and 3 run the previously described deposition phase and after some time the previously described purge water pumping phase also begins. Upon completion of this, when the level drops ensure that the second float switch 36 is switched over, the controller automatically switches the machine to normal mode, in which all phases indicated in Tables 1 to 5 are run sequentially.

The described embodiment is not the only possible solution according to the invention, since in the case of a plant for higher volumes of purified water, more than two pre-treatment reactors 2 can be used and the device need not be arranged in a common housing 5. The purification stage 4 does not have to be a settling tank but As a filter, the device need not be equipped with either a disinfectant dispenser 16 or an aerobic stabilizer 12 of excess sludge. In a different configuration of reactors 2 and 3, the aerators 301, 302 and 303 as well as the mammoth pumps 7 need not be 9,11,14 and 17.

11 may be connected to a single common compressed air source 31 or, in large installations, the main and sub aerators 301 and 302 may be connected to the compressed air source 31 separately via the third regulating element 34, as shown in FIG. 5. In order to prevent clogging of the coarse dirt trap 1, it may also be equipped with another auxiliary aerator (not shown).

Industrial usability

The intermittent multi-stage biological wastewater treatment method and apparatus for carrying out the method according to the invention can be used in wastewater treatment plant projects and constructions, especially for sewage from 2 to 1000 connected residents from residential buildings, hotels, boarding houses, restaurants, gas stations stations and smaller industrial enterprises.

Claims (10)

PATENT CLAIMS 1. Method of multi-stage biological waste water treatment with intermittent operation in a plant comprising at least two pre-treatment reactors, a purification reactor and an internal air recirculation circuit connected to at least one compressed air source, characterized in that depending on selected time intervals or amount of effluent according to pre-set parameters in each pre-treatment reactor there is a controlled separate cleaning process consisting of aeration of purified water and a selected combination of cleaning phases consisting of mixing of purified water and settling of sludge while ensuring pre-pumping of pre-treated water into the cleaning reactor. process consisting of mixing and aerating purified water and settling of sludge while ensuring pumping of purified water, recirculation Return sludge to each or any of the pretreatment reactors and occasionally pumping off the excess sludge when the start or end of individual stages of the purification processes in the pretreatment reactors or in the purification reactor is initiated by evaluating the level fluctuations in the purification reactor by float switches. . 2. The method of multi-stage biological waste water treatment according to claim 1, characterized in that, when the waste water flow to the plant is stopped, pressurized air is supplied intermittently to the main aerators of the pretreatment reactors and the purification reactor by adjusting the different timing levels. mixing or aerating the water without draining the purified water. 3. The method of multi-stage biological sewage treatment according to claim 1, characterized in that when the level in the activation reactor is raised above the maximum level, the supply of pressurized air from the source to the purification reactor or to all reactors is stopped first and after a certain time interval. - 13 necessary to ensure that the settling phase is carried out, the phase of pumping purified water from the purification reactor begins, after which the operation of the plant is again switched to the normal mode, in which all purification phases are carried out in succession. and 4. Intermittent biological wastewater treatment plant with intermittent activated sludge activation system comprising at least two pre-treatment reactors and a purge reactor connected in series and an internal compressed air circulation circuit with aerators located in all reactors, characterized in that the interconnected pre-treatment reactors (2) are completely separated from the cleaning reactor (3) with which the last of the pre-treatment reactors (22) is connected by a first pilot mammoth pump (7) connected to the first air float armature (8) when at the inlet (6) In the first pre-treatment reactor (21) a coarse dirt trap (1) is placed, the activation reactor (3) being equipped with a second control mammoth pump (9) for pumping clean water connected to the second float control valve (10) and the first me a mutant return sludge pump (14) into each of the pretreatment reactors (2) and a mammoth pump (11) of excess sludge. Apparatus according to claim 4, characterized in that the mammoth excess sludge pump (11) is led through an aerobic excess sludge tabulator (12) to a sludge tank (13), which is connected to one of the pre-treatment reactors (2) to allow drainage sludge water back into the purification process. Apparatus according to claim 4 and 5, characterized in that it comprises a purification stage (4) into which a second control mammoth pump (9) is provided and which is equipped with a clean water outlet (15) and a second mammoth pump (17) of a return sludge. into a first pre-treatment reactor (21). Apparatus according to claims 4 to 6, characterized in that all the mammoth pumps (7, 9, 11, 14, 17) and the aerators (301, 302, 303, 304) of the reactors (2, 3) of the post-purification stage (7). 4) and the excess sludge stabilizer (12) are - 14 with a compressed air source (31) connected via a first control element (32) or a second control element (33). Apparatus according to claim 7, characterized in that the main aerators (301) of the reactors (2, 3), the first air float armature (8) and the first mammoth are connected to one branch of the circulation air circuit coming from the first control element (32). the return sludge pump (14) and the second branch are connected to the auxiliary aerators (302) of the pre-cleaning reactors (2), second to the float control valve (10), the second control mammoth pump (9) and the second mammoth return sludge pump (17); secondly, a second auxiliary aerator (304) of the excess sludge stabilizer (12), the mammoth pump (11) of the excess sludge being connected to the second regulating element (33) in parallel connected to the second branch of the first regulating element (32) and the auxiliary aerator (33) 303) the finishing stage (4). Apparatus according to claims 4 to 8, characterized in that the cleaning reactor (3) is provided with a first through hole (18) for passing the activated sludge foam into the last pre-treatment reactor (22) and the post-cleaning stage (4) is provided with a second through hole (19) for passing the activated sludge foam into the first pretreatment reactor (21). Device according to claims 4 to 9, characterized in that the cleaning stage (4) is equipped with a disinfectant dispenser (16).