WO2009119961A1

WO2009119961A1 - System for controlling advanced wastewater treatment apparatus with two-stage reactor

Info

Publication number: WO2009119961A1
Application number: PCT/KR2008/007322
Authority: WO
Inventors: Jin Hwan Oh; Tae Kyun Kim; Seung Kap Jang
Original assignee: Sam Chang Enterprise Co., Ltd
Priority date: 2008-03-26
Filing date: 2008-12-11
Publication date: 2009-10-01
Also published as: KR20090102377A; KR100935916B1

Abstract

A system for controlling an advanced wastewater treatment apparatus with a two-stage reactor to maximize an efficiency of nutrient removal by using an automated control unit, as well as reducing work loading and operation expense is disclosed. The system includes the steps of measuring an inflow rate and water quality of sewage flowing through a pretreatment unit including a grit remover and an initial precipitation reactor by using a plurality of measuring sensors 50, subjecting the sewage to aeration and agitation by selecting any one of a first reactor 10 and a second reactor 20, in which a time of an anoxic, semi-anaerobic, anaerobic and aerobic process is controlled in accordance with a measured value of the measuring sensors 50 or connecting the first and second reactors 10 and 20 in parallel, discharging treated water drained from any one of the first reactor 10 and the second reactor 20 to a final precipitation reactor 30, and returning surplus sludge or water treated by the final precipitation reactor 30 to the first reactor 10 or the second reactor 20.

Description

SYSTEM FOR CONTROLLING ADVANCED WASTEWATER TREATMENT APPARATUS WITH TWO-STAGE REACTOR

Technical Field

[1] The present invention relates to a system for controlling an advanced wastewater treatment apparatus which removes nutrients contained in sewage or wastewater, and more particularly, to a system for controlling an advanced wastewater treatment apparatus with a two-stage reactor which can maximize an efficiency of nutrient removal by using an automated control unit, as well as reducing work loading and operation expenses. Background Art

[2] Various contaminants contained in sewage or wastewater are generally treated by an activated sludge method. Due to increase in environmental regulations, an advanced wastewater treatment method capable of removing heavy metals and various nutrients, such as nitrogen or phosphor, contained in the sewage or wastewater is recently developed.

[3] The advanced wastewater treatment method has evolved from a manned control system which is directly monitored and controlled by an operator to an automated control system using a computer-assisted control unit because of the development of information processing technology or factory automation.

[4] As shown in FIG. 1, the control system includes a step of supplying sewage containing nutrients into a reactor 100, a step of performing agitation and aeration of the sewage stored in the reactor by an operator, and a step of discharging the sewage treated by the reactor to a precipitation reactor through a carrier duct.

[5] In this instance, the sludge 300 stored in the precipitation reactor 200 is carried to a supply line of the reactor 100 through a return duct 400.

[6] After the nutrients containing nitrogen and phosphor are removed from the sewage supplied to the reactor 100 by using an agitator and aerator which are operated by an operator, the sewage is discharged to the precipitation reactor 200.

[7] Since the conventional control system performs the agitation and aeration process on the sewage stored in the reactor 100 in accordance with judgment of the operator, it is not suitable for inflow rate of the sewage and environmental conditions such as weather or time. Therefore, there are problems that the conventional control system is suffered from a human loss or power loss and the effectiveness of monitoring and control operation is deteriorated.

[8] In addition, in case the control system removes the nutrients such as nitrogen and phosphor at one time, a multiple-stage biological reactor including an anaerobic reactor, an anoxic reactor and an aerobic reactor should be sequentially operated. Therefore, since an exclusive area of the treatment apparatus is increased, an installation cost is increased, and operation or maintenance expenses are thus increased. Disclosure of Invention Technical Problem

[9] Accordingly, the present invention is directed to a system for controlling an advanced wastewater treatment apparatus that substantially obviates one or more problems due to limitations and disadvantages of the related art.

[10] One object of the present invention is to provide a system for controlling an advanced wastewater treatment apparatus with a two-stage reactor to maximize an efficiency of nutrient removal by using an automated control unit, as well as reducing work loading and operation expense. Technical Solution

[11] In order to accomplish these objects, there is provided a system for controlling an advanced wastewater treatment apparatus with a two-stage reactor, comprising the steps of: measuring an inflow rate and water quality of sewage flowing through a pre- treatment unit including a grit remover and an initial precipitation reactor by using a plurality of measuring sensors; subjecting the sewage to aeration and agitation by selecting any one of a first reactor and a second reactor, in which a time of an anoxic, semi-anaerobic, anaerobic and aerobic process is controlled in accordance with a measured value of the measuring sensors or connecting the first and second reactors in parallel; discharging treated water drained from any one of the first reactor and the second reactor to a final precipitation reactor; and returning surplus sludge or water treated by the final precipitation reactor 30 to the first reactor or the second reactor.

[12]

Advantageous Effects

[13] According to the system for controlling the advanced wastewater treatment apparatus with the two-stage reactor, since the treatment process of the advanced wastewater treatment apparatus is automatically controlled, water quality can be constantly maintained, irrespective of inflow rate of the sewage and environmental conditions such as weather or time.

[14] In addition, since the control system removes the nutrients such as nitrogen and phosphor at one time, an exclusive area of the treatment apparatus can be reduced, and installation costs or maintenance expenses are thus decreased. Brief Description of the Drawings

[15] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:

[16] FIG. 1 is a block diagram depicting a conventional system for controlling the advanced wastewater treatment apparatus;

[17] FIG. 2 is a view depicting the first process of a system for controlling the advanced wastewater treatment apparatus according to the present invention;

[18] FIG. 3 is a view depicting the second process of a system for controlling the advanced wastewater treatment apparatus according to the present invention;

[19] FIG. 4 is a view depicting the third process of a system for controlling the advanced wastewater treatment apparatus according to the present invention; and

[20] FIG. 5 is a flowchart depicting a system for controlling the advanced wastewater treatment apparatus according to the present invention. Best Mode for Carrying Out the Invention

[21] A preferred embodiment according to the present invention will now be explained with reference to the accompanying drawings.

[22] FIGs. 2 to 4 are views depicting the first to third processes of a system for controlling the advanced wastewater treatment apparatus according to the present invention.

[23] The system includes the steps of measuring an inflow rate and water quality of sewage flowing through a pretreatment unit including a grit remover and an initial precipitation reactor by using a measuring senor 50; subjecting the sewage to aeration and agitation by selecting any one of a first reactor 10 and a second reactor 20, in which a time of an anoxic, semi-anaerobic, anaerobic andaerobic process is controlled in accordance with a measured value of the measuring sensor 50 or connecting the first and second reactors 10 and 20 in parallel; discharging treated water drained from any one of the first reactor 10 and the second reactor 20 to a final precipitation reactor 30; and returning surplus sludge or water treated by the final precipitation reactor 30 to the first reactor 10 or the second reactor 20.

[24] The first reactor 10 and the second reactor 20 are installed in the advanced wastewater treatment apparatus according to the present invention, in which a control process of the first and second reactors 10 and 20 is automated to reduce operation steps and expenses needed for the control process.

[25] The system of the present invention further includes a first process of simultaneously operating the first reactor 10 and the second reactor 20 when the inflow rate of the sewage is more than a set value, and a second process of selectively operating any one of the first reactor 10 and the second reactor 20 when the inflow rate of the sewage is less than a set value. [26] The measuring step is to measure the inflow rate and water quality of the sewage flowing through the pretreatment unit including the grit remover and the initial precipitation reactor by using a plurality of measuring sensors 50. An aeration process, an agitation process and a chemical input process are carried out in accordance with the measured values of the measuring sensors 50.

[27] The treatment step is to treat the sewage pretreated at the measuring step, and is divided into a first step of continuously treating the sewage by connecting the first reactor with the second reactor in parallel, a second process of continuously treating the sewage by connecting the first reactor with the second reactor, and a third process of treating the sewage by selecting any one of the first and second reactors.

[28] The discharging step is to discharge the water treated by any one of the first reactor

10 and the second reactor 20 to the final precipitation reactor 30, and the carrying step is to carry the surplus sludge and the water treated by the final precipitation reactor 30 to the first reactor 10 or the second reactor 20.

[29] In case of the first process, if the first reactor 10 performs the anoxic, semi-anaerobic, anaerobic and aerobic process, the second reactor 20 performs precipitation and discharge of overlying water. If the second reactor 20 performs the anoxic, semi- anaerobic, anaerobic and aerobic process, the first reactor 10 performs the anoxic, semi-anaerobic, anaerobic and aerobic process after inflow of raw water.

[30] In case of the second process, the first reactor 10 or the second reactor 20 performs the anoxic, semi-anaerobic, anaerobic and aerobic process to carry out the advanced treatment process of nitrogen or phosphor. Also, in case of the third process, the raw water is supplied to any one of the first and second reactors to perform the anoxic, semi-anaerobic, anaerobic and aerobic process.

[31] In this instance, the description of the aeration and agitation reactors installed in the first and second reactors 10 and 20 will be omitted herein.

[32] The plurality of measuring sensors 50 are installed in the passage of the inflow water, the sensors including an inflow rate detecting sensor, an ORP (Oxidation-Reduction Potential) sensor for measuring quality of the inflow water, a hydrogen ion concentration sensor, an oxygen sensor, a temperature sensor, and an MLSS (Mixed Liquor Suspended Solid) sensor. The first and second reactors 10 and 20 are separately operated, or are connected in parallel to each other, in accordance with a signal of the measuring sensors 50.

[33] The system of the present invention sets the inflow rate of the sewage as 3Q. If the inflow rate is more than 3Q, the first and second reactors 10 and 20 are simultaneously operated. If the inflow rate is less than 3Q, the first and second reactors 10 and 20 are selectively operated. In particular, the inflow rate of the sewage can be adjusted in accordance with seasonal or time factor. [34] It is preferable that the measuring sensors 50 are set to measure the quality of sewage until the sewage reaches proper water quality, so that the system is operated to perform the agitation and aeration process by adjusting the operation time and speed. In particular, information measured by the measuring sensors 50 is stored in a database to compare with measurement of the water quality at a next cycle.

[35] The reason why the inflow rate of the sewage is set as 3Q is that the operation time and performance of the system are adjusted in accordance with a sewage volume which is varied depending upon a time factor, such as morning and night, and a weather time, such as summer and winter.

[36] The first reactor 10 changes an oxygen supply time of an intermittent aeration reactor with an anaerobic, anoxic and aerobic state and a carrying volume of the sludge between the first reactor and the second reactor in accordance with ammonium nitrogen of the sewage supplied from the initial precipitation reactor.

[37] The first reactor 10 may be operated in a semi- anaerobic state by using agitation and aeration under an anoxic state, and may be monitored by the controller receiving the signal outputted from the measuring sensors 50.

[38] The operating time and intensity of the agitation and aeration in the first reactor 10 may be adjusted by the signal of the controller, and the first reactor 10 may adjust the water quality by using the sewage returned from the second reactor 20 or the final precipitation reactor 30.

[39] Preferably, a coupling 13 with a flowmeter is provided between the first reactor 10 and the second reactor 20 to convey a proper volume of the sludge returned by a pump. Also, a return duct 11 may be installed between the final precipitation reactor 30 and the first reactor 10 to carry the surplus sludge from the final precipitation reactor 30.

[40] Also, another return duct 11 may be installed between the final precipitation reactor

30 and the second reactor 20 to carry the surplus sludge from the final precipitation reactor 30.

[41] Also, a return duct 12 may be installed between the first reactor 10 and the second reactor 20 to carry the sewage nitrified by the second reactor.

[42] As the controller employs the database, the agitation process of the first reactor may be performed if a measured value of the hydrogen ion concentration sensor is more than a reference value or the measured value of the temperature sensor is less than a reference value.

[43] Also, the aeration process of the first reactor may be performed if a measured value of the ORP sensor is less than a reference value or the measured value of the temperature sensor is less than a reference value.

[44] The second reactor 20 is operated in the aerobic and semi-aerobic state, and includes a controller receiving a signal outputted from the measuring sensors 50, so that the second reactor 20 can be monitored.

[45] The agitation process of the second reactor 20 may be performed if the measured value (pH) of the hydrogen ion concentration sensor is more than a reference value or the measured value of the temperature sensor is less than a reference value. Also, the aeration process of the second reactor may be performed if the measured value of the ORP sensor is less than a reference value or the measured value of the temperature sensor is less than a reference value.

[46] The final precipitation reactor 30 finally treats the sewage discharged from the first reactor 10 or the second reactor 20. In case of the first process, the final precipitation reactor 30 temporarily stores the water intermittently supplied from the first reactor 10 or the second reactor 20. In case of the second process, the final precipitation reactor 30 finally treats the water continuously supplied from the first reactor 10 or the second reactor 20. In case of the third process, the raw water supplied from the influent state is discharged through the initial precipitation reactor, the first reactor 10, the second reactor 20, the final precipitation reactor 30, and the phosphor removing filter 40.

[47] The final precipitation reactor 30 treats the water treated by the first reactor 10 or the second reactor 20, and then discharges it through the first reactor 10 or the second reactor 20.

[48] The phosphor removing filter 40 is installed on a rear end of the advanced wastewater treatment apparatus to remove the phosphor by filtration and absorption. Preferably, the phosphor removing filter 40 is made of a material having a filtration and absorption function to filter SS components and absorb the phosphor.

[49] In this instance, it is preferable that the phosphor removing filter 40 consists of a pre- filtering material of a synthetic resin made of fiber or polyurethane to filter the SS component contained in the discharged water, and a main filtering material of a hy- drotacite- or zirconium-based absorption agent to absorb the phosphoric component.

[50] Preferably, a valve 47 such as a gate valve or motored valve is installed in the discharge duct of the final precipitation reactor 30. The valve is driven in accordance with the signal of a phosphor concentration sensor 45 to detect concentration of the phosphor contained in the discharged water.

[51] With the advanced wastewater treatment apparatus according to the present invention, the phosphor concentration sensor 45 for detecting the concentration of phosphor contained in the discharged water is mounted in the discharge duct of the final precipitation reactor 30, and monitors T-N and T-P in real time. If the removal of T-P is temporarily unstable, the valve 47 is immediately opened, so that the discharged water of the final precipitation reactor 30 is turned to the phosphor removing filter 40 to constantly maintain the quality of the discharged water at the highest level.

[52] The control of the first process according to the present invention will now be described with reference to FIG. 4.

[53] When the advanced wastewater treatment apparatus according to the present invention is operated, as shown in FIG. 4, the quality and inflow rate of the sewage supplied from the pretreatment process are continuously monitored by the measuring sensors 50.

[54] If the measured value of the ORP sensor is less than a reference value, the aeration process is performed. If the measured value of the ORP sensor is more than a reference value, it proceeds to a next step.

[55] In this instance, if the measured value of the inflow rate detecting sensor is more than a reference value, it proceeds to the first process or the third process. If the measured value of the inflow rate detecting sensor is less than a reference value, it proceeds to the second process.

[56] In particular, when the second process is performed, the first reactor 10 or the second reactor 20 is selected by the controller.

[57] Then, if the measured value of the hydrogen ion concentration sensor is less than a reference value, it proceeds to a chemical treating process, such as methanol. If the measured value of the hydrogen ion concentration sensor is more than a reference value, it proceeds to a next step.

[58] In this instance, the sewage is returned from the second reactor 20 to the inflow duct of the first reactor 10, otherwise the surplus sludge is carried from the final precipitation reactor 30 to the inflow duct of the first reactor 10.

[59] Then, if the measured value of the hydrogen ion concentration sensor is more than a reference value, the agitation process is performed. If the measured value of the hydrogen ion concentration sensor is less than a reference value, it proceeds to a next step.

[60] More specifically, the water quality of the sewage supplied from the pretreatment process is satisfied to the set values of the ORP sensor and the hydrogen ion concentration sensor, the inflow water is supplied to and retreated by the first reactor 10.

[61] Then, if the measured value of the MLSS sensor is more than a reference value, the sewage is discharged to the final precipitation reactor 30. If the measured value of the MLSS sensor is less than a reference value, the sewage is discharged to the second reactor 20.

[62] In case of the discharged water stored in the second reactor 20, only the precipitate and the overlying water are discharged from the second reactor 20 to the final precipitation reactor 30, which will be not described herein.

[63] The water discharged from the final precipitation reactor 30 is continuously measured by the phosphor concentration sensor 45. If the measured value of the phosphor concentration sensor 45 is more than a reference value, the drain duct of the final precipitation reactor 30 is opened.

[64] If a content of the phosphor contained in the discharged water of the final precipitation reactor 30 is more than a reference value, the discharged water flows through the phosphor removing filter 40 to maintain the water quality of the discharged water at the highest level.

[65] If the second process is performed in accordance with the measured value of the inflow rate detecting sensor, the anoxic, semi-anaerobic, anaerobic and aerobic process is continuously performed by any one of the first reactor 10 and the second reactor 20.

[66] Also, since the third process is performed in cooperation with the first reactor and the second reactor, the anoxic, semi- anaerobic, anaerobic and aerobic process of the first and second reactors, the final precipitation and discharge of the phosphor removing filter are continuously performed.

[67] As a result of performing the first process by using the advanced wastewater treatment apparatus, at least 70 to 80% of nitrogen or phosphor is removed from the sewage, and most of nutrients are removed from the sewage, thereby using the discharged water as swimmable water.

[68] The forgoing embodiment is merely exemplary and is not to be construed as limiting the present invention. The present teachings can be readily applied to other types of apparatus. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art.

[69]

Claims

[1] A system for controlling an advanced wastewater treatment apparatus with a two-stage reactor, comprising the steps of: measuring an inflow rate and water quality of sewage flowing through a pre- treatment unit including a grit remover and an initial precipitation reactor by using a plurality of measuring sensors 50; subjecting the sewage to aeration and agitation by selecting any one of a first reactor 10 and a second reactor 20, in which a time of an anoxic, semi-anaerobic, anaerobic and aerobic process is controlled in accordance with a measured value of the measuring sensors 50 or connecting the first and second reactors 10 and 20 in parallel; discharging treated water drained from any one of the first reactor 10 and the second reactor 20 to a final precipitation reactor 30; and returning surplus sludge or water treated by the final precipitation reactor 30 to the first reactor 10 or the second reactor 20.

[2] The system as claimed in claim 1, wherein a set value of the inflow rate of the sewage is 3 Q in the measuring step.

[3] The system as claimed in claim 1, wherein in the measuring step, an aeration process, an agitation process and a chemical input process are carried out in accordance with the measured values of the measuring sensors 50.

[4] The system as claimed in claim 1, wherein the measuring sensors 50 include an inflow rate detecting sensor, an ORP (Oxidation-Reduction Potential) sensor for measuring quality of inflow water, a hydrogen ion concentration sensor, an oxygen sensor, a temperature sensor, and an MLSS (Mixed Liquor Suspended Solid) sensor, which are mounted in an inflow duct of the first reactor 10.

[5] The system as claimed in claim 1, wherein the first reactor 10 and the second reactor 20 are connected to each other by a coupling 13 which is opened if a measured value of the hydrogen ion concentration sensor is less than a reference number.

[6] The system as claimed in claim 1, wherein the first reactor 10 and the final precipitation reactor 30 are connected to each other by a return duct 11, through which the surplus sludge is returned to the first reactor 10 from the final precipitation reactor 30.

[7] The system as claimed in claim 1, wherein the second reactor 20 and the final precipitation reactor 30 are connected to each other by a return duct 11, through which the surplus sludge is returned to the second reactor 20 from the final precipitation reactor 30.

[8] The system as claimed in claim 1 or 4, wherein an agitation process of the first reactor 10 is performed if a measured value of the hydrogen ion concentration sensor is more than a reference value or a measured value of the temperature sensor is less than a reference value.

[9] The system as claimed in claim 1 or 4, wherein an aeration process of the first reactor 10 is performed if a measured value of the ORP sensor is less than a reference value or a measured value of the temperature sensor is less than a reference value.

[10] The system as claimed in claim 1 or 4, wherein an agitation process of the second reactor 20 is performed if a measured value of the hydrogen ion concentration sensor is more than a reference value or a measured value of the temperature sensor is less than a reference value.

[11] A system for controlling an advanced wastewater treatment apparatus with a two-stage reactor, comprising the steps of: measuring an inflow rate and water quality of sewage flowing through a pre- treatment unit including a grit remover and an initial precipitation reactor by using a plurality of measuring sensors 50; subjecting the sewage to aeration and agitation by connecting a first reactor 10 and a second reactor 20 in series, in which a time of an anoxic, semi-anaerobic, anaerobic and aerobic process is controlled in accordance with a measured value of the measuring sensors 50; discharging treated water drained from any one of the first reactor 10 and the second reactor 20 to a final precipitation reactor 30; and returning surplus sludge or water treated by the final precipitation reactor 30 to the first reactor 10 or the second reactor 20.

[12] The system as claimed in claim 11, wherein an aeration of the first and second reactors 10 and 20 is performed in accordance with a measured value of an oxygen sensor among the measuring sensors 50.

[13] The system as claimed in claim 11, wherein the final precipitation reactor 30 is provided in a discharge duct thereof with a phosphor removing filter 40 for filtering a phosphor component contained in the sewage.

[14] .The system as claimed in claim 11, wherein the final precipitation reactor 30 is provided in a discharge duct thereof with a phosphor concentration sensor 45 for detecting concentration of phosphor contained in the sewage to open or close the discharge duct.

[15] The system as claimed in claim 11 or 14, wherein the final precipitation reactor

30 is provided in the discharge duct thereof with a valve 47 which is operated in accordance with a signal of the phosphor concentration sensor 45. [16] The system as claimed in claim 11, wherein the first reactor 10 and the second reactor 20 are connected to each other by a return duct 12 for returning the sewage nitrified by the second reactor 20 or the final precipitation reactor 30.