KR101887331B1 - Reverse osmosis concentrated water treatment system using excess sludge generated in bioreactor - Google Patents

Abstract

Disclosed is a reverse osmosis concentrated water treatment system which reduces maintenance costs such as drug costs and power costs and simplifies the size of a structure while making a treatment facility more stable, by removing the chemical oxygen demand (NBDCOD) and refractory nitrogen which cannot be biodegraded from concentrated water generated during reverse osmosis by using excess sludge. The concentrated water is generated during reverse osmosis when the reuse of water is performed through applying a membrane and a reverse osmosis device for processing treated wastewater treated biologically in a wastewater treatment facility and securing the stable water quality regardless of water temperature.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reverse osmosis concentrated water treatment system using an excess sludge generated in a biological reactor,

The present invention relates to a reverse osmosis concentrated water treatment system, and more particularly, to a reverse osmosis concentrated water treatment system using excess sludge produced in a biological reactor.

The reverse osmosis membrane (R / O-MBR) process is a simple treatment system, but it requires additional equipment to operate and maintain it, which causes increase in facility cost and increase in maintenance cost. In addition, the concentrated water generated from the reverse osmosis (R / O) facility has a high pollutant load and can not be discharged to the outside of the system without being treated. When the water is circulated to the sewage treatment facility, It causes problems.

In particular, when the reverse osmosis membrane process is applied to a large scale wastewater treatment facility, the amount of concentrated water is increased and a lot of facilities are needed to treat the wastewater.

Korean Patent Laid-Open Publication No. 2015-0085990 discloses an MBR unit including an anaerobic tank, a stabilization tank, an anoxic tank, an oxic tank and an immersion tank; An RO membrane module configured at the downstream end of the MBR unit, for separating the dissolved organic matter in the treated water treated by the MBR unit and discharging the concentrated water containing the dissolved organic matter; And an ozone reaction tank connected to the concentrated water discharge side of the RO membrane module and containing concentrated water and injecting ozone by the concentrated water. However, in the treatment of concentrated water using excess sludge Is not described.

In the present invention, when treated water biologically treated in a wastewater treatment facility is treated with a membrane and reverse osmosis treatment device to ensure stable water quality regardless of water temperature, water can be reused, By using sludge, it is possible to reduce the maintenance cost such as the chemical cost and power ratio by eliminating the biodegradable chemical oxygen demand (NBDCOD) and the refractory nitrogen, and also the treatment facility is stabilized and the reverse osmosis concentrated water treatment System.

In order to solve the above problems, the present invention is a reverse osmosis concentrated water treatment system for a large scale wastewater treatment facility using a membrane unit and a reverse osmosis module, wherein the excess sludge of the bioreactor and the concentrated water discharged from the reverse osmosis module are stored Sludge reservoir; A carbon source supply facility for supplying an organic carbon source to the sludge storage tank; An activated carbon admixture tank in which concentrated water uniformly mixed with excess sludge and carbon source flows in the sludge storage tank; An activated carbon supply facility for supplying powder activated carbon to the activated carbon admixture tank; An agglomeration tank for supplying a flocculant to the sludge mixed with the activated carbon admixture; A sedimentation tank for subjecting the concentrated water obtained through the coagulation and mixing tank to solid-liquid separation and supplying a supernatant water to the flow rate regulator; And a sludge dewater for supplying the water of the settling tank to the flow rate adjusting tank and discharging the remaining sludge to the dewatering cake. The present invention also provides a reverse osmosis concentrated water treatment system using the excess sludge.

The membrane unit may further include a bioreactor into which the waste water and wastewater are introduced from the flow rate adjusting tank and the contaminants are decomposed by the microorganisms, a membrane filtration tank that separates the treated water and the solids from the bioreactor, And a membrane treatment water tank provided with a membrane treatment water supply pump for supplying the reverse osmosis module to the reverse osmosis module.

The reverse osmosis module may include a reverse osmosis feed pump configured to be disposed downstream of the membrane unit, the reverse osmosis feed pump supplying the treated water passing through the membrane unit to the reverse osmosis module; A reverse osmosis filter for separating concentrated water containing dissolved organic matter, ionic material and particulate matter from the treated water supplied from the reverse osmosis feed pump; A reverse osmosis pressure pump located at a front end of the reverse osmosis filter and passing concentrated water through the reverse osmosis filter at a high pressure; And a treatment water supply tank located at a front end of the reverse osmosis feed pump, a carbon filter positioned at a rear end of the bag filter, a microfilter disposed at a rear end of the carbon filter, and a sodium hypochlorite (NaOCl) And a pretreatment unit including a reducing agent, a hardening substance being removed from the front end of the micro filter, and a sodium hydroxide (NaOH) being introduced at a front end of the reverse osmosis pressure pump. And a reverse osmosis concentrated water treatment system using the same.

In the present invention, when treated water biologically treated in a wastewater treatment facility is treated with a membrane and reverse osmosis treatment device to ensure stable water quality regardless of water temperature, water can be reused, By using sludge, it is possible to reduce the maintenance cost such as the chemical cost and power ratio by eliminating the biodegradable chemical oxygen demand (NBDCOD) and the refractory nitrogen, and also the treatment facility is stabilized and the reverse osmosis concentrated water treatment System can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an overall process diagram of a wastewater treatment facility including a concentrated water treatment system according to an embodiment of the present invention; Fig.
2 is a process diagram of a membrane unit according to an embodiment of the present invention,
3 is a process diagram of a reverse osmosis module according to one embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to denote the same parts throughout the specification, and the details of the present invention will be described with reference to the drawings. Also, throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements, unless specifically stated otherwise.

1 is an overall process diagram of a wastewater treatment facility including a concentrated water treatment system 100 according to one embodiment of the present invention.

1, the present invention is a reverse osmosis concentrated water treatment system 100 for a large scale wastewater treatment facility to which a membrane unit 200 and a reverse osmosis module 300 are applied, wherein the excess sludge of the bioreactor 210, A sludge storage tank (110) for storing the concentrated water discharged from the reverse osmosis module (300); A carbon source supply facility 111 for supplying an organic carbon source to the sludge storage tank 110; An activated carbon admixture tank 120 in which concentrated water homogeneously mixed with excess sludge and carbon source flows in the sludge storage tank 110; An activated carbon supply facility 121 for supplying powdered activated carbon to the activated carbon admixture tank 120; A coagulation admixture tank 130 for supplying coagulant to the mixed sludge passed through the activated carbon admixture tank 120; A sedimentation tank (140) for solid-liquid separation of the concentrated water mixed through the coagulation and mixing tank (130) and supplying the supernatant water to the flow rate regulator; And a sludge dewatering unit (150) for supplying the representative water of the settling tank (140) to the flow rate adjusting tank and discharging the remaining sludge to the dewatering cake.

2 is a process diagram of a membrane unit 200 according to an embodiment of the present invention.

2, the membrane unit 200 according to the present invention includes a biological treatment process used in MBR (Membrane Bio-Reactor) process and a structure for a solids separation process using a separation membrane. Therefore, the membrane unit 200 includes a bioreactor 210 in which waste water and wastewater are introduced from the flow rate adjusting tank and the contaminants are decomposed by microorganisms, a membrane filtration tank 220 separating the treated water and the solids from the bioreactor 210, And a membrane treatment water tank 230 having a membrane treatment water supply pump 231 for storing treatment water separated from the membrane filtration tank 220 and supplying the treated water to the reverse osmosis module 300.

The bioreactor 210 refers to a site where a biological treatment process such as a single bioreactor, an AO process, and an AO process proceeds, and does not limit the reaction by a specific microorganism. In the case of the AO process and the A2O process, the surplus sludge can be discharged from the sedimentation basin. The excess sludge is discharged out of the system to remove the phosphorus. Therefore, an excess sludge pump 211 may be installed in the bioreactor 210 and the secondary settler 212.

On the other hand, in the settling basin, the activated sludge can be returned to maintain the bioreactor concentration.

The membrane filtration tank 220 is subjected to solid-liquid separation with sludge-containing solid matter and treated water through a submerged flat membrane 221. Accordingly, the membrane filtration tank 220 may include a membrane treatment water suction pump 222 for conveying the treated water having passed through the immersion type flat membrane 221 to the membrane treatment water tank 230.

The membrane treatment water tank 230 is a structure for storing the treated water passing through the bioreactor 210 and the membrane filtration tank 220. The membrane treatment tank 230 minimizes changes in water quality and quantity of treated water, Can be smoothly performed. Therefore, the membrane treatment water supply pump 231 for supplying the stored treatment water to the reverse osmosis module 300 may be provided.

The reverse osmosis module 300 passes the treated water passing through the membrane unit 200 through a reverse osmosis filter 320 using a high-pressure pump to remove TN, TP, chromogenic materials and other ionic materials And concentrated water containing dissolved organic matter, ionic substances and particulate matter.

The reverse osmosis module 300 may include a reverse osmosis feed pump 310, a reverse osmosis filter 320, a reverse osmosis pressurization pump 330, and a preprocessor 340.

3 is a process diagram of a reverse osmosis module 300 according to an embodiment of the present invention.

3, the reverse osmosis module 300 is disposed at a downstream end of the membrane unit 200 and includes a reverse osmosis supply unit 300 for supplying treated water having passed through the membrane unit 200 to the reverse osmosis module 300, A reverse osmosis filter 320 for separating concentrated water containing dissolved organic matter, ionic substances and particulate matter from the treated water supplied from the reverse osmosis feed pump 310; A reverse osmosis pressurization pump 330 positioned at a front end of the reverse osmosis feed pump 310 and passing concentrated water through the reverse osmosis filter 320 at a high pressure, a bag filter 341 located at a front end of the reverse osmosis feed pump 310, A tank 342, a carbon filter 343 located at the rear end of the bag filter 341, a microfilter 344 located at the rear end of the carbon filter 343, and a sodium hypochlorite (NaOCl ), A reducing agent is introduced into the micro filter 344, and a hard substance Removed, it may include a pre-processing unit 340 comprising a drug input system 345 to inject a sodium hydroxide (NaOH) in the reverse osmosis pressure pump 330, the front end.

The reverse osmosis feed pump 310 serves as a backwash pump that uniformly feeds the treated water passing through the membrane unit 200 to the carbon filter and removes impurities from the carbon filter 343 do.

The reverse osmosis filter 320 is provided with a reverse osmosis membrane to separate the reused water and the concentrated water. The reverse osmosis pressurization pump 330 located at the upstream end of the reverse osmosis filter 320 is operated at a high pressure of 10 kg / Treated water having passed through the pretreatment unit 340 is separated and separated into concentrated water containing reused water, dissolved organic matter, ionic substances and particulate matter, from which TN, TP, chromogenic substances and other ionic substances have been removed do. The reused water can be discharged through post treatment such as putting sterilizing chemicals in the discharged water tank, adjusting the pH, or supplied to each use place.

In addition, the reverse osmosis pressurization pump 330 is automatically stopped according to the set values of the pressure switches installed at the front and rear ends to prevent damage due to idling of the pump and damage due to abnormal high-pressure operation in the reverse osmosis membrane, Through the measurement sensor provided at the front and rear ends of the two-way filter 320, all the data such as the pressure rise, the flow rate decrease, and the operation time are accumulated and analyzed, so that the operation can be stably and efficiently controlled.

The pretreatment unit 340 removes contaminants before the process water passes through the reverse osmosis filter 320 to reduce the load of the reverse osmosis filter 320. The pretreatment unit includes a bag filter 341, 342, a carbon filter 343, a microfilter 344, and a drug injection system 345. [

The bag filter 341 is located at the front end of the reverse osmosis feed pump 310 and removes solids contained in the treated water passing through the membrane unit 200 by using a filter cloth to be stored in the treated water supply tank 342 do. The treated water supply tank 342 can minimize the variation in the quantity of water supplied to the reverse osmosis module 300 and maintain it constantly, and is connected to the reverse osmosis supply pump 310.

The carbon filter 343 removes the organic matter, chromaticity, and ion components contained in the treated water to reduce the load on the post-treatment facility, removes components that cause biofouling, (320).

The microfilter 344 removes particulate matter of 5 microns or more to allow the reverse osmosis filter 320 to operate stably.

The chemical injection system 345 includes a sodium hypochlorite (NaOCl) dosing system for removing microorganisms and bacteria contained in the treated water by chemicals at the front end of the carbon filter 343, a reverse osmosis An SBS dosing system for injecting a reducing agent to prevent damage to the membrane, and an anti-scintillation dosing system (an antiscalant system) for controlling the scale fouling (adherence) of the reverse osmosis membrane by controlling the hard substances contained in the treated water at the front end of the micro- (NaOH) dosing system which suppresses scale fouling (adherence) of the reverse osmosis membrane by adjusting the pH of the treated water at the front end of the reverse osmosis pressurization pump 330.

The dosing amount is automatically controlled by a measurement sensor provided at the rear end of the carbon filter 343 and the micro filter 344, And may be configured to be automatically controlled by a PLC or a PC depending on whether or not the storage tank level sensor and the operation system are operated.

On the other hand, when the concentrated water is circulated to the flow rate adjusting tank of the sewage elevation treatment facility to treat the biodegradable chemical oxygen demand (NBDCOD) and the refractory nitrogen contained in the concentrated water excluded from the reverse osmosis module 300, The concentration of the reverse osmosis concentrated water can not be coagulated by sedimentation or flocculation treatment at a low suspended solids concentration (SS) concentration. Therefore, the present invention can be applied to the case where the excess sludge of the bioreactor is used, NBDCOD and refractory nitrogen.

Therefore, the sludge storage tank 110 stores the excess sludge of the bioreactor 210 and the concentrated water of the reverse osmosis module 300 together. The surplus sludge is transferred to the sludge storage tank 110 under the bioreactor 210 and an excess sludge pump installed in the sedimentation tank.

The carbon source supply facility 111 supplies an organic carbon source to the sludge storage tank 110 to homogenize the carbon source to cause denitrification of the excess sludge to remove the degradable nitrogen. The organic carbon source for the denitrification oxidation can be first put into the sludge storage tank 110 to perform the denitrification and the NBDCOD and the powder activated carbon for removing the refractory nitrogen may be added and reacted in order to maximize the reduction of the drug cost and the treatment efficiency. It is also possible to control the quality of treated water by continuous injection.

The activated carbon supply facility 121 mixes the powdered activated carbon with water and feeds the activated sludge into the activated carbon admixture tank 120 through which the excess sludge from the sludge storage tank 110 flows. Thus, a storage tank for storing the powdered activated carbon and a storage tank agitator for mixing the powdered activated carbon with the water may be included. In the activated carbon admixture tank 120, the powdered activated carbon and the concentrated water mixed with the excess sludge are mixed and reacted to remove NBDCOD and refractory nitrogen.

The COD removed by the adsorption action of the granular activated carbon is 40 ~ 236 kg · COD / kg. In the case of the powdered activated carbon, the COD removal efficiency is further increased because the specific surface area is much larger than that of the granular activated carbon. The following chemical formula 1 is a biological denitrification reaction formula, and the following chemical formula 2 represents a COD required for biological denitrification.

[Chemical Formula 1]

(2)

The coagulation admixture tank 130 is provided with a flocculant supply facility 131 and a flocculant (polymer) is added to the mixed sludge (excess sludge + concentrated water + activated carbon) reacted in the activated carbon admixture tank 120 to remove sludge flocs Thereby improving sedimentation. The sedimentation tank (140) separates the reacted sludge floc from the coagulation admixture tank (130) by solid-liquid separation and separates the supernatant water and the sludge. The sludge dewatering unit 150 discharges the dewatering cake in which the sludge in the settling tank is concentrated and dehydrated.

In this way, when physically and biochemically treating the concentrated water using the excess sludge generated in the biological treatment process, there is no need for separate medicine for coagulation, thereby reducing maintenance expenses such as drug cost and power cost, The size of the frame and structure can be simplified.

The preferred embodiments of the present invention have been described in detail with reference to the drawings. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Accordingly, the scope of the present invention is defined by the appended claims rather than the description of the invention, and all changes or modifications derived from the meaning, scope and equivalence of the claims are deemed to be included in the scope of the present invention. .

100: concentrated water treatment system 110: sludge storage tank
111: Carbon source supply facility 120: Activated carbon admixture tank
121: Activated carbon supply facility 130: Coagulation admixture tank
131: coagulant supply facility 140: settling tank
150: Sludge dehydrator
200: Membrane unit 210: Bioreactor
211: surplus sludge pump 212: secondary sedimentation tank
220: membrane filtration tank 221: immersed flat membrane
222: membrane treatment water suction pump 230: membrane treatment tank
231: membrane treated water supply pump
300: Reverse osmosis module 310: Reverse osmosis feed pump
320: Reverse osmosis filter 330: Reverse osmosis pressure pump
340: Pretreatment unit 341: Bag filter
342: treated water supply tank 343: carbon filter
344: Microfilter 345: Drug injection system

Claims (3)

As a reverse osmosis concentrated water treatment system for a large scale wastewater treatment facility using a membrane unit and a reverse osmosis module,
A sludge storage tank for storing the excess sludge of the bioreactor and the concentrated water discharged from the reverse osmosis module;
A carbon source supply facility for supplying an organic carbon source to the sludge storage tank;
An activated carbon admixture tank in which concentrated water uniformly mixed with excess sludge and carbon source flows in the sludge storage tank;
An activated carbon supply facility for supplying powder activated carbon to the activated carbon admixture tank;
An agglomeration tank for supplying a flocculant to the sludge mixed with the activated carbon admixture;
A sedimentation tank for subjecting the concentrated water obtained through the coagulation and mixing tank to solid-liquid separation and supplying the supernatant water to the flow rate regulator; And
And a sludge dewater for supplying the water of the settling tank to the flow rate adjusting tank and discharging the remaining sludge to the dewatering cake. The method according to claim 1,
Wherein the membrane unit comprises: a biological reaction tank in which lower and wastewater flows from a flow rate control tank and decomposes contaminants by microorganisms; a membrane filtration tank that separates treated water and solids from the bioreactor; And a membrane treatment water tank provided with a membrane treatment water supply pump supplied to the reverse osmosis module. The method according to claim 1,
Wherein the reverse osmosis module is disposed at a downstream end of the membrane unit, and the reverse osmosis feed pump supplies the treated water passing through the membrane unit to the reverse osmosis module;
A reverse osmosis filter for separating concentrated water containing dissolved organic matter, ionic material and particulate matter from the treated water supplied from the reverse osmosis feed pump;
A reverse osmosis pressure pump located at a front end of the reverse osmosis filter and passing concentrated water through the reverse osmosis filter at a high pressure; And
A bag filter disposed at a front end of the reverse osmosis feed pump, a treated water supply tank,
A carbon filter disposed at a rear end of the bag filter,
A micro filter disposed at the downstream end of the carbon filter,
A pretreatment step of adding a sodium hypochlorite (NaOCl) and a reducing agent at the front end of the carbon filter, removing a hard substance at a front end of the micro filter, and injecting sodium hydroxide (NaOH) at the front end of the reverse osmosis pressure pump part;
And a reverse osmosis condensed water treatment system using excess sludge.

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