Integrated sewage treatment process

Abstract

The invention provides an integrated sewage treatment process. The device comprises an ABFT tank, a clarification tank, an ozone contact water supply tank, an ozone contact tank and a biological activated carbon filter tank, wherein the ABFT tank is communicated with the clarification tank, the clarification tank is communicated with the ozone contact water supply tank, the ozone contact water supply tank is communicated with the ozone contact tank, and the ozone contact tank is communicated with the biological activated carbon filter tank. Integrated equipment is adopted, manufacturing is easy, overhauling is convenient, and the occupied area is greatly saved. The equipment disclosed by the invention is suitable for sewage treatment engineering with relatively poor biodegradability, especially for advanced treatment of circulating water and sewage, and meanwhile, indexes such as total phosphorus and SS (suspended solids) of effluent of the equipment are controlled to meet corresponding emission standards.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of sewage treatment, in particular, to an integrated sewage treatment process. BACKGROUND

[0002] With the increasing attention of the state to environmental protection, the water quality requirements of the power plant effluent in various regions are also increasing. As the main component of the power plant effluent, the discharge standard of circulating water is becoming more and more stringent. In some areas, the main biochemical indicators in the sewage are required to be improved from the first A standard of the Discharge Standard of Pollutants in Urban Sewage Treatment Plant (COD≤50mg / L, NH3-N≤5mg / L) to the IV standard of the Environmental Quality Standard for Surface Water (COD≤30mg / L, NH3-N≤ 1.5mg / L).

[0003] As a major water user in the thermal power industry, circulating cooling water is generally supplemented by effluent (reclaimed water) from a sewage treatment plant or surface water. After concentration by the cooling system, the biodegradability of the refractory organic matter in the sewage is poor, and the traditional biochemical treatment method cannot meet the environmental protection discharge requirements of COD and ammonia nitrogen in the sewage.

[0004] Aerobic biological fluidized bed (ABFT) is a new sewage treatment technology for removing ammonia nitrogen in recent years, which is a double biological reactor that combines the advantages of traditional activated sludge method and biofilm method. In ABFT, 10% to 25% of the effective volume of the pool is added to the high-efficiency microbial carrier, which enhances the biological load by loading specific denitrifying bacteria to ensure the high-efficiency and stable treatment effect of ABFT. During operation, each carrier has anaerobic, anoxic and aerobic functional zones from inside to outside, which forms numerous nitrification-denitrification reactors and effectively guarantees the denitrification effect. Compared with the traditional activated sludge method, ABFT process saves the secondary sedimentation tank and other equipment, and has a relatively simple process and small land occupation. Meanwhile, ABFT process also has the advantages of no backwash, no sludge bulking, no sludge return, strong impact load resistance, and significant engineering economy. SUMMARY

[0005] Therefore, the present application aims to provide an integrated sewage treatment process which can quickly and efficiently treat circulating water sewage.

[0006] To solve the above technical problems, the technical scheme of the present application is as follows: an integrated sewage treatment process, comprising an ABFT pool, a clarifier, an ozone contact water supply pool, an ozone contact pool and a biological activated carbon filter pool; wherein the ABFT pool is in communication with the clarifier, the clarifier is in communication with the ozone contact water supply pool, the ozone contact water supply pool is in communication with the ozone contact pool, and the ozone contact pool is in communication with the biological activated carbon filter pool.

[0007] The further improvement of the present application is that the ABFT pool is provided with an ABFT water inlet on one side, and an ABFT air inlet is formed on the top of the ABFT pool, and a water outlet channel is arranged between the ABFT pool and the clarification tank; the ozone contact tank is provided with an ozone contact tank air inlet and an ozone contact tank air outlet; and the biological activated carbon filter tank is provided with a biological activated carbon filter tank air inlet and a filter tank aeration fan connecting port.

[0008] The further improvement of the present application is that the clarification tank is provided with a conical flow guide cylinder which is communicated with the water outlet channel.

[0009] The further improvement of the present application is that the sidewall of the water outlet channel is provided with a central water inlet pipe which is communicated with the conical flow guide cylinder.

[0010] The further improvement of the present application is that the central water inlet pipe is provided with a pipe mixer.

[0011] The further improvement of the present application is that a plurality of layers of porous fillers are arranged in the ABFT pool, and a grid plate is arranged on the top and bottom of each layer of the porous fillers.

[0012] The further improvement of the present application is that the ABFT pool is provided with an aeration pipe at the bottom, and the ABFT pool is connected with a water inlet pipe, and the water inlet pipe is provided with a pipe mixer.

[0013] The further improvement of the present application is that the clarification tank is provided with a mud scraping device and a conical mud bucket at the bottom, the bottom of the mud bucket is provided with a blowdown port, the inside of the clarification tank is provided with a slanted plate area, and the upper part of the clarification tank is provided with a water collecting tank.

[0014] The further improvement of the present application is that the ozone contact water tank is arranged below the ozone contact tank, and the ozone contact water tank is provided with a water supply pump.

[0015] The further improvement of the present application is that the ozone contact tank is provided with an aeration disc uniformly installed at the bottom, the ozone contact tank is closed, the ozone contact tank is provided with an air outlet at the top, the air outlet is connected with an ozone tail gas destroyer, and the biological activated carbon filter tank is provided with a filter layer and a supporting layer.

[0016] The technical effects of the present application mainly include the following aspects: This invention enables rapid and efficient treatment of circulating wastewater, allowing the effluent from the clarifier to enter the ozone contact tank. This ensures that the suspended solids (SS) in the ozone contact tank are not excessively high, guaranteeing the effectiveness of ozone oxidation. The ozone-treated effluent, with its higher oxygen content, then enters the biological activated carbon filter, meeting the dissolved oxygen requirements of the tanks. This integrated device is simple to manufacture, easy to maintain, and significantly saves floor space. The equipment is suitable for wastewater treatment projects with poor biodegradability, particularly for the advanced treatment of circulating wastewater, while simultaneously controlling effluent total phosphorus and SS levels to meet relevant emission standards. This equipment is simple, efficient, easy to automate, and operates stably. It can also be combined with other circulating wastewater reuse processes to achieve comprehensive treatment of circulating wastewater. This invention targets the treatment of circulating wastewater from thermal power plants with poor biodegradability. After treatment, the wastewater can meet the Class IV standard of the "Surface Water Environmental Quality Standard" (COD≤30mg / L, NH3-N≤1.5mg / L). The integrated equipment used in this invention is easy to construct. Due to the ozone contact water supply tank, ozone contact tank and biological activated carbon filter, it can realize a clarification-decarbonization combined process, which is suitable for new construction and renovation projects.

[0017] Furthermore, this invention can make full use of the internal elevation differences of the system and adopt gravity flow in many places, which reduces energy consumption and also reduces the installation cost of mechanical equipment such as water pumps.

[0018] Furthermore, the ozone contact oxidation in this invention employs microporous aeration, which greatly increases the contact area between the water and ozone, resulting in a significant improvement in the oxidation effect. Attached Figure Description

[0019] Figure 1 A plan view of an integrated device for degrading biochemical indicators of wastewater from thermal power plants; Figure 2 Elevation view of an integrated device for degrading biochemical indicators of wastewater from thermal power plant circulating water.

[0020] Attached reference numerals: a-ABFT inlet; b-ABFT air inlet; c-clarifier inlet; d-ozone contact water supply tank outlet; e-ozone contact tank inlet; f-ozone contact tank air inlet; g-ozone contact tank exhaust outlet; h-ozone contact tank outlet; i-biological activated carbon filter inlet; j-biological activated carbon filter air inlet; k-biological activated carbon filter outlet; l-filter aeration blower connection port; m-ozone contact water supply tank inlet; n-clarifier outlet; 1-ABFT tank; 2-outlet channel; 3-conical guide tube; 4-collection trough; 5-ozone contact water supply tank; 6-feed pump; 7-ozone contact tank; 8-biological activated carbon filter; 9-aeration pipe; 10-inclined plate area; 11-aeration disc; 12-filter layer. Detailed Implementation

[0021] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, so that the technical solution of the present invention can be more easily understood and mastered.

[0022] See Figure 1 and Figure 2 This invention discloses an integrated device for degrading biochemical indicators of circulating wastewater from thermal power plants, comprising an ABFT (Aerated Biological Fluidized Bed) tank 1, a clarifier, an ozone contact feedwater tank 5, an ozone contact tank 7, and a biological activated carbon filter 8. The ABFT tank 1 is connected to the clarifier, the clarifier is connected to the ozone contact feedwater tank 7, the ozone contact feedwater tank 5 is connected to the ozone contact tank 7, and the ozone contact tank 7 is connected to the biological activated carbon filter 8. An ABFT inlet a is provided on one side of the ABFT tank 1, an ABFT air inlet b is provided at the top of the ABFT tank 1, an outlet channel 2 is provided between the ABFT tank 1 and the clarifier, a conical guide tube 3 connected to the outlet channel 2 is provided on one side of the clarifier, and a water collection trough 4 is provided at the top of the clarifier.

[0023] The ozone contact tank 7 is equipped with an ozone contact tank inlet f and an ozone contact tank exhaust outlet g.

[0024] The biological activated carbon filter 8 is equipped with a biological activated carbon filter inlet j. The biological activated carbon filter 8 is also equipped with a filter aeration blower connection port i. The effluent from ABFT tank 1 flows by gravity through the inlet c of the clarifier to the clarifier. The effluent from the clarifier flows by gravity through the clarifier outlet n to the inlet m of the ozone contact water supply tank. It then enters the ozone contact water supply tank 5 through the inlet m, and is pumped to the ozone contact water supply tank 7 through the outlet d and the water supply pump 6. The effluent from the ozone contact water supply tank 7 through the inlet e, and flows by gravity through the outlet h of the ozone contact water supply tank to the inlet i of the biological activated carbon filter. It then enters the biological activated carbon filter 8 through the inlet i, and is finally discharged through the outlet k of the biological activated carbon filter.

[0025] The ABFT tank 1 uses an S-shaped inlet. The porous packing material inside the tank can be configured in two or more layers depending on the tank height, with each layer spaced 2-3 meters apart. A grid plate is laid at the bottom of each layer to support the packing material, and the top of the last layer is also covered with a grid plate to prevent the packing material from overflowing with the water flow. ABFT tank 1 is configured with two groups based on the influent volume; the two groups can operate simultaneously or independently. An aeration pipe 9, specifically a perforated aeration pipe, is installed at the bottom of ABFT tank 1. The perforated aeration pipe provides uniform upward intermittent aeration, ensuring the dissolved oxygen level in the water remains at 3-4 mg / L. A pipe mixer is installed on the influent pipe of ABFT tank 1 to add a carbon source, providing the necessary carbon for the growth and metabolism of microorganisms in the tank. The dosage is adjusted according to the influent water quality and volume to maintain a carbon-to-nitrogen ratio close to 4:1. After a period of operation, as the biofilm thickness increases and the outer biofilm ages, increasing the internal resistance of the ABFT tank, the aeration time can be appropriately extended to blow off the aged biofilm, allowing it to enter the clarification tank and be discharged through its sludge outlet.

[0026] The effluent from ABFT tank 1 overflows into effluent channel 2, which is connected to the clarifier. A central inlet pipe is welded to the side wall of effluent channel 2, connecting to a conical guide tube 3. A pipe mixer is installed on the central inlet pipe for adding flocculants or coagulants. The bottom of the clarifier is equipped with a sludge scraper and a conical sludge hopper, with a drain outlet at the bottom of the sludge hopper. An inclined plate zone 10 is located inside the clarifier, and a water collection trough is located at the top. Two clarifiers are configured based on the incoming water quality and quantity.

[0027] The effluent from the clarifier flows by gravity into the ozone contact feedwater tank 5. The ozone contact feedwater tank 5 and the ozone contact tank 7 are arranged in an upper and lower structure, with the ozone contact feedwater tank 5 located below the ozone contact tank 7. An ozone contact feedwater pump is installed between them to lift the water to be treated from the ozone contact feedwater tank 5 into the ozone contact tank 7. Microporous aeration discs 11 are evenly installed at the bottom of the ozone contact tank 7 for microporous aeration. The ozone contact tank 7 is fully sealed, with an outlet at the top connected to an ozone tail gas destroyer. The ozone tail gas destroyer is used to reduce unconsumed ozone into oxygen and release it into the atmosphere.

[0028] The required ozone amount in the ozone contact tank 7 is in a ratio of (2-3):1 to the TOC mass in the circulating water discharge, and the ozone oxidation reaction time is 40-60 min.

[0029] The biological activated carbon filter 8 is configured with two or more groups according to the influent flow rate, with a main pipe for water intake, and operates in an upward continuous flow mode with a filtration rate of 6-10 m / h and an empty bed retention time of 4-5 h. The biological activated carbon filter 8 contains a filter layer 12 and a support layer, with a filter layer to support layer volume ratio of (6-8):1. The support layer consists of a pebble layer and a coarse sand pad, with pebble particle size of 10-20 mm and coarse sand particle size of 5-10 mm; the filter layer uses activated carbon with a particle size of 3-5 mm.

[0030] The biological activated carbon filter 8 uses bottom-mounted main pipe aeration. Aeration parameters are adjusted according to the incoming water quality, with blower operating parameters changed accordingly. Intermittent aeration maintains the dissolved oxygen level in the water at 5-6 mg / L. To ensure uniform aeration, a steel filter plate is used to seal the bottom of the filter 1-1.2m away. The filter plate has evenly spaced filter holes, each fitted with a long-handled filter head and a filter cap. Both the filter layer and the support layer described above are filled onto the filter plate.

[0031] The effluent from the biological activated carbon filter 8 flows into the effluent channel through the side wall water passage, and is discharged from the integrated equipment through the water outlet at the bottom of the effluent channel. The water passage is sealed with a stainless steel screen with a 2mm aperture.

[0032] After the biological activated carbon filter has been running for a period of time, when the operating resistance increases, the filter needs to be backwashed. Backwashing mainly involves air washing, air-water mixed washing, and rinsing. The backwashing steps are programmed into a sequential control program, and the specific backwashing parameters can be adjusted. The filter backwash inlet and the main inlet water use the same inlet.

[0033] The following are embodiments of processing using the equipment of the present invention.

[0034] The wastewater discharge volume of a certain factory's circulating water system is approximately 2 × 100 t / h. The main water quality indicators are shown in Table 1. Table 1. Main water quality indicators of wastewater from a certain factory's circulating water discharge.

[0035] The circulating water wastewater treatment system adopts this invention—an integrated device for degrading biochemical indicators of circulating water wastewater from thermal power plants, specifically as follows: Figure 1 As shown in Figure 2: ABFT consists of two groups, each group divided into two compartments, each compartment measuring 4.5m × 3m × 6m. Each compartment is filled with two layers of porous packing material, spaced 2m apart. The water flow is S-shaped, with a hydraulic retention time of 3 hours. Carbon source 3 uses a 20% sodium acetate trihydrate solution. There are two clarifiers, each with a treatment capacity of 100 m³ / h, using 10% polyaluminum chloride as the coagulant. The ozone contact feed tank measures 6m × 5m × 3m. The ozone contact pool measures 6m × 4m × 3m and is located above the ozone contact feed tank, with an ozone contact oxidation time of 40 minutes. There are three biological activated carbon filters, each measuring 6m × 6m × 6m, with a total effective volume of 216 m³ and an empty bed retention time of 4 hours. The filling heights of pebbles, coarse sand, and activated carbon are 0.2m, 0.1m, and 2.2m, respectively.

[0036] After commissioning and trial operation, the stable effluent quality of the project meets the Class IV standard of the "Surface Water Environmental Quality Standard". The main control indicators are COD≤30mg / L and ammonia nitrogen≤1.5mg / L. The effluent quality indicators are shown in Table 2.

[0037] Table 2 Main water quality indicators of system effluent

[0038] The equipment proposed in this invention for degrading the biochemical indicators of wastewater from thermal power plants has the following advantages: 1. This invention enables rapid and efficient treatment of power plant circulating water discharge, with tight and reasonable connections between each process. The effluent from the clarifier enters the ozone contact tank, ensuring that the suspended solids (SS) in the ozone contact tank are not excessively high, thus guaranteeing the effectiveness of ozone oxidation. The ozone-treated effluent, with its higher oxygen content, enters the biological activated carbon filter, meeting the dissolved oxygen requirements of the filter and reducing the operating time and frequency of the filter's aeration blowers, thereby saving energy.

[0039] 2. The present invention uses an integrated steel device, which is simple to manufacture, easy to maintain, and greatly saves floor space.

[0040] 3. This invention can make full use of the internal elevation difference of the system and adopt gravity flow in many places, which reduces energy consumption and reduces the installation cost of mechanical equipment such as water pumps.

[0041] 4. In this invention, the carbon source required by the ABFT unit can be added according to the quality of the incoming water, and the appropriate carbon-nitrogen ratio can be adjusted at any time, solving the problem of seasonal fluctuations in the quality of the circulating water discharge and incoming water. When the incoming water quality shows a high carbon and low nitrogen phenomenon, there is no need to add carbon source; on the contrary, additional carbon source needs to be added.

[0042] 5. In this invention, ozone contact oxidation uses microporous aeration, which greatly increases the contact area between the water and ozone, thus significantly improving the oxidation effect.

[0043] 6. The biological activated carbon filter in this invention uses activated carbon filter media with a large specific surface area, which not only has a good adsorption effect on pollutants in water, but also provides a better living environment for microorganisms in the water due to its porous characteristics. This allows the organic matter adsorbed in the activated carbon particles to be absorbed and utilized by microorganisms growing in the activated carbon channels, forming a natural adsorption-desorption process, which greatly extends the service life of activated carbon.

[0044] 7. The equipment in this invention is suitable for wastewater treatment projects with poor biodegradability, especially for the deep treatment of circulating water discharge. The method simultaneously controls the total phosphorus and SS indicators in the system effluent to meet the corresponding discharge standards.

[0045] 8. The equipment of this invention is simple and efficient, easy to automate, and operates stably. It can be combined with other circulating water wastewater reuse processes to achieve comprehensive treatment of circulating water wastewater. The equipment is welded from carbon steel with a rubber-lined inner wall for corrosion protection, offering advantages such as small footprint, simple manufacturing, and low initial investment. Simultaneously, this equipment can efficiently and stably treat circulating water wastewater with poor biodegradability, producing high-quality effluent, rapid start-up, high automation, low maintenance costs, and minimal impact from changes in hydraulic and water quality loads. After treatment, the circulating water wastewater meets high discharge standards and subsequent reuse requirements, resulting in significant environmental and economic benefits.

[0046] Of course, the above are just typical examples of the present invention. In addition, the present invention may have many other specific embodiments. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed by the present invention.

Claims

1. An integrated wastewater treatment process, characterized in that, It includes an ABFT tank (1), a clarifier, an ozone contact water supply tank (5), an ozone contact tank (7), and a biological activated carbon filter (8); wherein, the ABFT tank (1) is connected to the clarifier, the clarifier is connected to the ozone contact water supply tank (5), the ozone contact water supply tank (5) is connected to the ozone contact tank (7), and the ozone contact tank (7) is connected to the biological activated carbon filter (8).

2. The integrated wastewater treatment process according to claim 1, characterized in that, An ABFT inlet (a) is provided on one side of the ABFT tank (1), an ABFT air inlet (b) is provided on the top of the ABFT tank (1), and an outlet channel (2) is provided between the ABFT tank (1) and the clarification tank; an ozone contact tank inlet (f) and an ozone contact tank exhaust outlet (g) are provided on the ozone contact tank (7); and a biological activated carbon filter inlet (j) and a filter aeration blower connection port (i) are provided on the biological activated carbon filter (8).

3. The integrated wastewater treatment process according to claim 2, characterized in that, A conical guide tube (3) connected to the outlet channel (2) is installed on one side of the clarification tank.

4. The integrated wastewater treatment process according to claim 3, characterized in that, The side wall of the outlet channel (2) is equipped with a central inlet pipe that is connected to the conical guide tube (3).

5. The integrated wastewater treatment process according to claim 4, characterized in that, A pipe mixer is installed on the central water inlet pipe.

6. The integrated wastewater treatment process according to claim 1, characterized in that, The ABFT tank (1) is equipped with several layers of porous packing material, and each layer of porous packing material is equipped with a grid plate at the top and bottom.

7. The integrated wastewater treatment process according to claim 1, characterized in that, An aeration pipe (9) is installed at the bottom of the ABFT tank (1); the ABFT tank (1) is connected to the inlet pipe, and a pipe mixer is installed on the inlet pipe.

8. The integrated wastewater treatment process according to claim 1, characterized in that, The bottom of the clarifier is equipped with a sludge scraping device and a conical sludge bucket. The bottom of the sludge bucket is equipped with a sewage outlet. The interior of the clarifier is equipped with an inclined plate area (10), and the upper part of the clarifier is equipped with a water collection trough (4).

9. The integrated wastewater treatment process according to claim 1, characterized in that, The ozone contact water supply tank (5) is located below the ozone contact tank (7), and a water supply pump (6) is installed between the ozone contact water supply tank (5) and the ozone contact tank (7).

10. The integrated wastewater treatment process according to claim 1, characterized in that, The bottom of the ozone contact tank (7) is uniformly equipped with aeration discs (11); the ozone contact tank (7) is closed, and the top of the ozone contact tank (7) is equipped with an air outlet, and the outlet is connected to an ozone tail gas destroyer; the biological activated carbon filter (8) is equipped with a filter layer (12) and a support layer.

Images