A mud membrane symbiotic water treatment system

Abstract

The present invention discloses a mud-film symbiotic water treatment system, including a CASS pool and a modular biomass filler membrane frame placed in the CASS pool; the modular biomass filler membrane frame is formed by splicing a plurality of groups of biomass filler membrane frame modules, and each group of biomass filler membrane frame modules is composed of a plurality of biomass filler membrane frame single blocks; wherein, the biomass filler membrane frame modules located in the biological selection area are all laid flat on the bottom surface of the pool body along the length direction; the biomass filler membrane frame modules located in the main reaction area are also laid flat on the bottom surface of the pool body along the length direction, but near the decanter, the biomass filler membrane frame modules are stacked in the height direction to the height of the liquid level to form a permeable wall. The present invention achieves the purpose of mud-film symbiosis by adding modular biomass fillers in the activated sludge system, and promotes the activated sludge and biofilm to jointly treat sewage. Compared with the prior art, the present invention not only does not need to add additional facilities, but also the effluent water quality can reach the quasi-fourth category water standard.

Description

Technical Field

[0001] The invention belongs to the field of municipal sewage treatment, and in particular relates to a mud-membrane symbiotic water treatment system. Background Art

[0002] Nowadays, in sewage treatment plant improvement projects, the IFAS process is mostly used. This process is based on the principle of increasing the amount of microorganisms by using mud membrane symbiosis to improve the pollutant removal rate, and currently uses suspended fillers as carriers for microorganisms. This process has the following two major defects during operation:

[0003] 1. The aeration system needs to be re-planned to meet certain hydraulic conditions and keep the suspended filler in a uniform and fluidized state;

[0004] 2. At the outlet of the biochemical pool, an anti-blocking system needs to be designed. Currently, the anti-blocking system consists of a grille and an aeration pipe. However, during operation, the grille will be covered with film, resulting in blockage of the grille holes.

[0005] The common point of the above two defects is that both require the modification of the aeration system and increase the power consumption. In addition, the current water plant effluent index is required to meet the standard of surface water level Class IV water, so there is a need for a water treatment process that can meet this standard without adding other treatment units. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention proposes a sludge-film symbiotic water treatment system, which forms a process for jointly treating sewage by activated sludge and biofilm. Not only is the design cost relatively low and the construction period relatively short, but it also contributes to the removal of SS, total nitrogen and total phosphorus, and can reduce the dosage of chemicals.

[0007] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0008] A sludge-membrane symbiotic water treatment system, which treats municipal sewage, is composed of a CASS pool (Cyclic-Activated-Sludge-System) and a modular biomass filler membrane frame designed in the CASS pool;

[0009] The CASS tank comprises a tank body, which is divided into a biological selection zone at the front and a main reaction zone at the rear by a retaining wall in the length direction; the bottom of the retaining wall is not connected to the bottom surface of the tank body, forming a water outlet; an inlet pipe for connecting municipal sewage is arranged above the biological selection zone; an aeration system is arranged at the bottom of the main reaction zone along the length direction, a decanter is arranged at the rear of the main reaction zone, and the water outlet of the decanter is connected to the water outlet pipe arranged at the rear end of the tank body; the bottom of the main reaction zone is connected to the bottom of the biological selection zone through a mixed liquid mixing pipe;

[0010] The modular biomass filler membrane frame includes several groups of biomass filler membrane frame modules spliced ​​together, and the number of the biomass filler membrane frame modules that need to be put in can be calculated according to the level of sewage improvement; wherein, the biomass filler membrane frame modules located in the biological selection area are all laid flat on the bottom surface of the biological selection area along the length direction; the biomass filler membrane frame modules located in the front and middle of the main reaction area are laid flat on the bottom surface of the front and middle of the main reaction area along the length direction; the biomass filler membrane frame modules located close to the decanter are stacked in the height direction to the liquid level to form a permeable wall;

[0011] Each group of the biomass filler membrane frame modules is composed of several biomass filler membrane frame blocks, and the biomass filler membrane frame blocks are made of new materials with high specific surface area, high film-hanging performance, carbon source and strong adsorption performance. Each of the biomass filler membrane frame blocks includes a rectangular main body structure, and end face protrusions and end face grooves are respectively arranged on the front and rear end faces of the main body structure, and the sizes of the end face protrusions and the end face grooves correspond to each other. Several side face protrusions are respectively arranged at equal distances on the left and right side faces of the main body structure, and a side face groove is formed between two adjacent side face protrusions on the same side, and the sizes of the side face protrusions and the side face grooves correspond to each other. Several large and small circular holes are opened on the upper and lower planes of the main body structure.

[0012] The present invention achieves the purpose of sludge-film symbiosis by adding modular biomass fillers with high specific surface area, high biofilm performance, carbon source and strong adsorption performance in the activated sludge system, forming a process for treating sewage together with activated sludge and biofilm.

[0013] The system features of the mud-film symbiotic water treatment system of the present invention are as follows:

[0014] 1. The influent is the municipal sewage after passing through the grit chamber;

[0015] 2. The system hydraulic retention time of the CASS pool is 10 hours, of which the hydraulic retention time of the biological selection zone is 2 hours and the hydraulic retention time of the main reaction zone is 8 hours;

[0016] 3. The sludge concentration of the CASS pool is 3500 mg / L;

[0017] 4. In the CASS pool, the volume of each group of the biomass filler membrane frame module is 6.3L, and the dimensions of length×width×height are 330mm×330mm×350mm. In the biomass filler membrane frame module, the volume of each biomass filler membrane frame is 0.7L, and the dimensions of length×width×thickness are 330mm×150mm×35mm;

[0018] 5. The filling rate of each group of biomass filler membrane frame modules is 3%-5%.

[0019] The system operation conditions of the mud-film symbiotic water treatment system of the present invention are as follows:

[0020] The system operation cycle is designed to be 6 hours (1 hour of water inlet period, 3 hours of aeration period, 1 hour of static sedimentation period and 1 hour of decanting period) or 4 hours (1 hour of water inlet period, 2 hours of aeration period, 0.5 hour of static sedimentation period and 0.5 hour of decanting period);

[0021] During the water inflow period: the main reaction zone returns sludge to the biological selection zone, the sludge return rate is 100%, and the sewage mainly undergoes denitrification reaction in the main reaction zone to remove total nitrogen and BOD5;

[0022] During the aeration period: after the water intake is completed, turn on the blower to maintain the dissolved oxygen concentration at 2-3 mg / L; this stage is to comprehensively remove ammonia nitrogen, total nitrogen, BOD5 and total phosphorus;

[0023] During the quiet period: This stage mainly removes SS;

[0024] During the decanting period: while achieving the drainage function, SS is better retained, so that the SS in the effluent can reach a level less than 10mg / L.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. The existing mud-film symbiotic system uses suspended fillers, while the present invention uses modular biomass fillers with high specific surface area, high biofilm performance, carbon source and strong adsorption performance. The removal rate of total nitrogen and total phosphorus in the existing technology is almost zero, while the present invention can improve the total nitrogen removal capacity by 20%, and the total nitrogen in the effluent can reach the level of 10 mg / L, and can improve the total phosphorus removal capacity by 30%, and the effluent SS value can reach the level of less than 5 mg / L, and the effluent water quality meets the quasi-fourth category water standard.

[0027] 2. After the CASS pool is combined with the biomass filler, the design size and design parameters of the system are changed compared with the single CASS pool. However, compared with the prior art that requires the installation of an aeration system and an anti-blocking system, the present invention does not require improvement of the aeration system or the design of an anti-blocking system. At the same time, the hydraulic retention time of the present invention can be shortened to 10 hours, which is 23% lower than the general design value. To put it another way, the pool capacity is reduced by 23% compared with the general CASS pool, thereby reducing both the design cost and the construction period.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. The specific implementation of the present invention is given in detail by the following embodiments and their accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0030] Figure 1 It is a schematic diagram of the overall structure of the mud-membrane symbiotic water treatment system of the present invention.

[0031] Figure 2 It is a structural schematic diagram of a single biomass filler membrane frame of the mud-membrane symbiotic water treatment system of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0033] See also Figure 1 As shown, a sludge-membrane symbiotic water treatment system, which treats municipal sewage, is composed of a CASS pool (Cyclic-Activated-Sludge-System) and a modular biomass filler membrane frame designed in the CASS pool;

[0034] The CASS tank comprises a tank body, which is divided into a biological selection zone (1) located at the front and a main reaction zone (2) located at the rear by a retaining wall (3) in the length direction; the bottom of the retaining wall (3) is not connected to the bottom surface of the tank body, forming a water outlet; an inlet pipe (4) for connecting to municipal sewage is arranged above the biological selection zone (1); an aeration system (5) is arranged at the bottom of the main reaction zone (2) along the length direction, and a decanter (6) is arranged at the rear of the main reaction zone (2), and the water outlet of the decanter (6) is connected to the water outlet pipe (7) arranged at the rear end of the tank body; the bottom of the main reaction zone (2) is connected to the bottom of the biological selection zone (1) through a mixed liquid mixing pipe (8);

[0035] The modular biomass filler membrane frame comprises a plurality of groups of biomass filler membrane frame modules (9) spliced ​​together, and the number of the biomass filler membrane frame modules that need to be deployed can be calculated according to the level of sewage improvement; wherein the biomass filler membrane frame modules (9) located in the biological selection area (1) are all laid flat on the bottom surface of the biological selection area (1) along the length direction; the biomass filler membrane frame modules (9) located in the front and middle parts of the main reaction area (2) are laid flat on the bottom surface of the front and middle parts of the main reaction area (2) along the length direction; the biomass filler membrane frame modules (9) located close to the decanter (6) are stacked in the height direction to the height of the liquid level to form a permeable wall;

[0036] See also Figure 2 As shown, each group of the biomass filler membrane frame modules (9) is composed of a plurality of biomass filler membrane frame blocks (10), and the biomass filler membrane frame blocks (10) are made of a new material with a high specific surface area, high film-forming performance, containing a carbon source, and having strong adsorption performance. Each of the biomass filler membrane frame blocks (10) includes a rectangular main structure (101), and the front and rear end faces of the main structure (101) are respectively provided with end face protrusions (102) and end face grooves (103), and the end faces The size of the face protrusion (102) corresponds to that of the end face groove (103); a plurality of side face protrusions (104) are equidistantly arranged on the left and right side faces of the main structure (101); a side groove (105) is formed between two adjacent side face protrusions (104) on the same side; and the size of the side face protrusion (104) corresponds to that of the side groove (105); and a plurality of through-going large circular holes (106) and small circular holes (107) are opened on the upper and lower planes of the main structure (101).

[0037] The system features of the mud-film symbiotic water treatment system of the present invention are as follows:

[0038] 1. The influent is the municipal sewage after passing through the grit chamber;

[0039] 2. The hydraulic retention time of the CASS pool is 10 hours, wherein the hydraulic retention time of the biological selection zone (1) is 2 hours, and the hydraulic retention time of the main reaction zone (2) is 8 hours;

[0040] 3. The sludge concentration of the CASS pool is 3500 mg / L;

[0041] 4. In the CASS pool, the volume of each group of the biomass filler membrane frame module (9) is 6.3 L, and the dimensions of length × width × height are 330 mm × 330 mm × 350 mm. In the biomass filler membrane frame module (9), the volume of each biomass filler membrane frame single block (10) is 0.7 L, and the dimensions of length × width × thickness are 330 mm × 150 mm × 35 mm.

[0042] 5. The filling rate of each group of biomass filler membrane frame modules (9) is 3%-5%.

[0043] The system operation conditions of the mud-film symbiotic water treatment system of the present invention are as follows:

[0044] The system operation cycle is designed to be 6 hours (1 hour of water inlet period, 3 hours of aeration period, 1 hour of static sedimentation period and 1 hour of decanting period) or 4 hours (1 hour of water inlet period, 2 hours of aeration period, 0.5 hour of static sedimentation period and 0.5 hour of decanting period);

[0045] During the water inflow period: the main reaction zone (2) returns sludge to the biological selection zone (1), the sludge return rate is 100%, and the sewage mainly undergoes denitrification reaction in the main reaction zone to remove total nitrogen and BOD5;

[0046] During the aeration period: after the water intake is completed, turn on the blower to maintain the dissolved oxygen concentration at 2-3 mg / L; this stage is to comprehensively remove ammonia nitrogen, total nitrogen, BOD5 and total phosphorus;

[0047] During the quiet period: This stage mainly removes SS;

[0048] During the decanting period: while achieving the drainage function, SS is better retained, so that the SS in the effluent can reach a level less than 10mg / L.

[0049] The following is a specific example to verify the operating effect of the mud membrane symbiotic water treatment system of the present invention:

[0050] The influent is the effluent from a sedimentation tank of a sewage treatment plant, and the influent indicators are COD=400 mg / L, BOD=5155 mg / L, SS=230 mg / L, ammonia nitrogen=40 mg / L, total nitrogen=53 mg / L, and total phosphorus=8 mg / L.

[0051] The operation cycle is 6 hours, and the process is: 1 hour water intake - 3 hours aeration - 1 hour static sedimentation - 1 hour decanting.

[0052] The modular biomass filler membrane frames are laid flat along the length direction in the front and middle of the CASS pool, and are stacked along the height direction 10 cm away from the decanter to form a permeable wall.

[0053] After 6 months of operation,

[0054] The effluent quality of the system can be stabilized at: COD≤40mg / L, BOD5≤10mg / L, SS≤10mg / L, ammonia nitrogen≤2mg / L, total nitrogen≤10mg / L, total phosphorus≤4mg / L. The effluent quality basically reaches the surface quasi-class IV water standard (except total nitrogen and total phosphorus).

[0055] At present, the effluent quality of the CASS pool of the water plant is COD≤50mg / L, BOD5≤10mg / L, SS≤20mg / L, ammonia nitrogen≤5mg / L, total nitrogen≤15mg / L, and total phosphorus≤6mg / L. It can be seen that compared with the effluent of the CASS pool of the water plant, the removal rate of total nitrogen in the system of the present invention is increased by 10%, and the removal rate of total phosphorus is increased by 30%. The effluent SS has reached the discharge standard of GB18918-2002 Level A.

[0056] Based on the above analysis, the advantages of this system are summarized as follows: 1. The effluent from the system of the present invention can meet the standard of Class IV surface water; 2. The contribution to the removal of total nitrogen can reduce the amount of carbon source added to the water plant; 3. The contribution to the removal of total phosphorus can reduce the amount of phosphorus removal agents added to the water plant (for a water plant with a capacity of 10,000 tons / day, the amount of ferrous sulfate can be reduced to 134kg / d, and the amount of aluminum chloride can be reduced to 62kg / d); 4. The pool capacity is 23% less than that of a general water plant CASS pool.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A mud-film symbiotic water treatment system, Features: It consists of a CASS tank and a modular biomass filler membrane frame designed in the CASS tank; The CASS tank comprises a tank body, which is divided into a biological selection zone (1) located at the front and a main reaction zone (2) located at the rear by a retaining wall (3) in the length direction; the bottom of the retaining wall (3) is not connected to the bottom surface of the tank body, forming a water outlet; an inlet pipe (4) for connecting to municipal sewage is arranged above the biological selection zone (1); an aeration system (5) is arranged at the bottom of the main reaction zone (2) along the length direction, and a decanter (6) is arranged at the rear of the main reaction zone (2), and the water outlet of the decanter (6) is connected to the water outlet pipe (7) arranged at the rear end of the tank body; the bottom of the main reaction zone (2) is connected to the bottom of the biological selection zone (1) through a mixed liquid mixing pipe (8); The modular biomass filler membrane frame comprises a plurality of groups of biomass filler membrane frame modules (9) spliced ​​together; wherein the biomass filler membrane frame modules (9) located in the biological selection area (1) are all laid flat on the bottom surface of the biological selection area (1) along the length direction; the biomass filler membrane frame modules (9) located in the front and middle parts of the main reaction area (2) are laid flat on the bottom surface of the front and middle parts of the main reaction area (2) along the length direction; the biomass filler membrane frame modules (9) located close to the decanter (6) are stacked in the height direction to the height of the liquid level to form a permeable wall; Each group of the biomass filler membrane frame modules (9) is composed of a plurality of biomass filler membrane frame blocks (10) having a high specific surface area, high film-forming performance, containing a carbon source, and having strong adsorption performance. Each of the biomass filler membrane frame blocks (10) comprises a rectangular main structure (101). The main structure (101) has end face protrusions (102) and end face grooves (103) respectively disposed on the front and rear end faces. The end face protrusions (102) and the end face grooves are connected to each other. (103), a plurality of side convex blocks (104) are equidistantly arranged on the left and right sides of the main structure (101), a side groove (105) is formed between two adjacent side convex blocks (104) on the same side, and the sizes of the side convex blocks (104) and the side grooves (105) correspond to each other, and a plurality of through-going large circular holes (106) and small circular holes (107) are opened on the upper and lower planes of the main structure (101); The volume of each biomass filler membrane frame (10) is 0.7 L, and the dimensions of length×width×thickness are 330 mm×150 mm×35 mm; the volume of each group of biomass filler membrane frame modules (9) is 6.3 L, and the dimensions of length×width×height are 330 mm×330 mm×350 mm; The system hydraulic retention time of the CASS pool is 10 hours, wherein the hydraulic retention time of the biological selection zone (1) is 2 hours, and the hydraulic retention time of the main reaction zone (2) is 8 hours.

2. The mud-membrane symbiotic water treatment system according to claim 1, Features: The sludge concentration of the CASS pool is 3500 mg / L.

3. The mud-membrane symbiotic water treatment system according to claim 1, Features: The filling rate of each group of biomass filler membrane frame modules (9) is 3%-5%.

4. The mud-membrane symbiotic water treatment system according to claim 1, Features: The system operation cycle is designed to be 6 hours, including 1 hour of water inlet period, 3 hours of aeration period, 1 hour of settling period and 1 hour of decanting period.

5. The mud-membrane symbiotic water treatment system according to claim 1, Features: The system operation cycle is designed to be 4 hours, including 1 hour of water inlet period, 2 hours of aeration period, 0.5 hours of settling period and 0.5 hours of decanting period.

6. The mud-membrane symbiotic water treatment system according to claim 4 or 5, Features: During the water inflow period, the return flow rate of the sludge from the main reaction zone (2) to the biological selection zone (1) is 100%.

7. The mud-membrane symbiotic water treatment system according to claim 4 or 5, Features: During the aeration period, the dissolved oxygen concentration was maintained at 2-3 mg / L.

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