Filter structure of sand filter for sewage treatment

Abstract

The utility model provides a filter structure of a sand filter for sewage treatment, which comprises the sand filter, a plurality of rows of sand filter devices are arranged in the sand filter, an overflow weir is arranged between two adjacent sand filter devices in each row, and autotrophic denitrification filler is filled in the sand filter devices; a water inlet pipe is arranged in the water inlet tank, and the end part of the water inlet pipe is communicated with the first sand filtering device in each column. The sewage treatment efficiency and quality are improved, the operation cost is also reduced, and a more economical, environment-friendly and sustainable solution is provided for urban sewage treatment plants.

Description

Technical Field

[0001] The utility model relates to the field of sewage treatment, in particular to a filtering structure of a sand filter tank for sewage treatment. Background Art

[0002] The domestic sewage treatment process of urban sewage treatment plants mainly includes primary treatment, secondary treatment, tertiary treatment and other process links. Among them, primary treatment mainly uses physical methods to remove large floating objects, suspended solids, gravel, stones, etc. in sewage. Secondary treatment mainly uses biological treatment methods to remove organic matter in sewage (such as COD, BOD, TP, TN, NH3-N, etc.). Tertiary treatment is also called deep treatment. In the deep treatment process, it mainly uses physical and chemical methods to further remove fine suspended particles and some soluble pollutants in sewage. Sometimes it is also necessary to use specific biological treatment processes to remove nitrogen and phosphorus in sewage to prevent eutrophication of water bodies. Among them, sand filter is a common treatment unit in the tertiary treatment process. Sand filter mainly plays the role of denitrification and removal of suspended solids (SS) in the tertiary sewage treatment process. The operation of sand filter directly affects whether the effluent water quality of urban sewage treatment plants can meet the standards.

[0003] The existing sand filter is mainly composed of a filter (which can be made of carbon steel, stainless steel, fiberglass or reinforced concrete), a water distributor, a sand guide hopper, a sand washer, an air lift pump, etc. The raw water enters the filter through the water inlet pipe, is evenly distributed through the water distributor at the bottom, and then flows upward in the reverse direction to the filter bed. The water flows from bottom to top through the activated sand filter bed. The pollutants in the water are intercepted by the filter bed and the water quality is purified. The sand particles containing pollutants are lifted to the top of the sand washer by the action of the air compressor. The pollutants on the sand surface are separated by the turbulent flow of the water. The cleaned sand particles are returned to the sand bed by gravity, and the generated sewage is discharged from the sewage outlet of the filter. This cycle is repeated to continuously purify domestic sewage.

[0004] In some areas, there are often high requirements for total nitrogen in the effluent from treated domestic sewage. Traditional activated sand filters, in actual operation, experience frequent backwashing, making biofilm formation difficult. Denitrification filters are also commonly reported to experience large fluctuations in total nitrogen (TN) removal rates. Furthermore, sand washers are demanding to operate and are prone to sand leakage, resulting in a high risk of effluent meeting standards and high operating costs. Therefore, it is necessary to modify traditional sand filters to address the existing issues of unstable denitrification performance and high operating costs caused by severe sand leakage. Utility Model Content

[0005] The main purpose of the utility model is to provide a filtering structure of a sand filter tank for sewage treatment, so as to solve the problems in the above-mentioned background technology.

[0006] In order to solve the above technical problems, the technical solution adopted by the utility model is as follows: comprising a sand filter tank, wherein a plurality of rows of sand filter devices are provided in the sand filter tank, an overflow weir is provided between two adjacent sand filter devices in each row, and the sand filter devices are filled with autotrophic denitrification fillers;

[0007] The upper part of the sand filter is provided with an inlet pool, the lower part is provided with an outlet pool, the inlet pool is provided with an inlet pipe, and the end of the inlet pipe is connected to the first sand filter device in each row.

[0008] Preferably, the end of the water inlet pipe is a bell mouth, and a water inlet pump and a water inlet hose are provided on the water inlet pipe, and the sewage in the water inlet pool is passed into the bell mouth of the end of the water inlet pipe through the water inlet pump and the water inlet hose.

[0009] Preferably, a flow meter is provided on the water inlet hose, and the flow meter is linked with the water inlet pump to control the water inlet volume.

[0010] Preferably, a water storage tank is provided on one side of the top of the overflow weir, and the water storage tank is connected to the water inlet of the next sand filter device.

[0011] Preferably, the autotrophic denitrification filler is a composite active biological carrier or a sulfur autotrophic denitrification biological filler.

[0012] Preferably, the liquid levels in the multiple sand filter devices in each row are lowered sequentially to form an overflow liquid level difference.

[0013] The utility model provides a filtration structure of a sand filter tank for sewage treatment, which has the following beneficial effects:

[0014] 1. Continuous operation: The sand filter does not need to be shut down for backwashing, which improves the filtration efficiency.

[0015] 2. Low energy consumption: The sand filter is filled with autotrophic denitrification filler, which does not require shutdown for backwashing. It replaces the sand lifting and washing conditions of the traditional sand filter, saves electricity and reduces energy consumption.

[0016] 3. Strong resistance to shock load: It can withstand high concentration SS influent water for a long time, and the effluent water quality is stable.

[0017] 4. Easy maintenance: simple backwashing method, low backwashing frequency, automatic control, easy and convenient operation and maintenance.

[0018] 5. It has diversified functions and meets the demand for extreme denitrification. It can control the nitrate nitrogen in the effluent below 1 mg / L and can achieve the simultaneous removal of TN, TP and SS.

[0019] 6. Green and environmentally friendly: The autotrophic denitrification filler filled in the sand filter uses inorganic compounds as electron donors to reduce nitrate nitrogen in the water to N2. It does not require external addition of organic carbon sources, saves carbon source addition, does not cause an increase in COD, reduces carbon emissions, is green and environmentally friendly, has a low sludge production rate, and reduces sludge disposal costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0021] Figure 1 This is a top view of the overall structure of the utility model;

[0022] Figure 2 This utility model Figure 1 A partial enlarged view of

[0023] Figure 3 This utility model Figure 1 AA partial cross-sectional view in;

[0024] In the figure: sand filter 1; sand filter device 2; overflow weir 3; water inlet pool 4; water inlet pipe 5; water outlet pool 6; water storage tank 7; autotrophic denitrification filler 8. DETAILED DESCRIPTION

[0025] like Figures 1-3 As shown, a filtration structure of a sand filter tank for sewage treatment includes a sand filter tank 1, wherein a plurality of rows of sand filter devices 2 are provided in the sand filter tank 1, an overflow weir 3 is provided between two adjacent sand filter devices 2 in each row, and the sand filter devices 2 are filled with autotrophic denitrification fillers 8;

[0026] The sand filter 1 is provided with an inlet pool 4 at the top and an outlet pool 6 at the bottom. An inlet pipe 5 is provided in the inlet pool 4, and the end of the inlet pipe 5 is connected to the first sand filter device 2 in each column. In this example, the original active sand filler in the traditional sand filter is removed and replaced with an autotrophic denitrification filler 8. An overflow weir 3 is installed between the two adjacent sand filter devices 2 in each column of the sand filter 1 to separate them. The sewage is filtered multiple times through multiple sand filter devices 2 in sequence to ensure the water filtration quality. The plane size of each sand filter device 2 is 4.90×2.35m, the filtration method is upward flow, and the effective filtration area is 11m 2 , the filtered water volume is 5.5~56m 3 / h, denitrification capacity is 5~15mg / L, and the amount of autotrophic denitrification filler is 20~30t.

[0027] The sand filter tank 1 is the main structure of the entire system, which is used to accommodate and treat the sewage to be filtered. There are multiple columns of sand filter devices 2 inside the sand filter tank 1. The sand filter device 2 in each column is responsible for a filtration stage. These devices are filled with autotrophic denitrification fillers 8. The overflow weir 3 is a structure arranged between adjacent sand filter devices in each column. The purpose is to control the direction and speed of the water flow and ensure that the sewage can flow evenly through each sand filter device. The water inlet tank 4 is located at the upper part of the sand filter tank and is used to receive the sewage to be treated. The water inlet pipe 5 transports sewage from the outside to the water inlet tank, and its end is connected to the first sand filter device in each column, which can ensure that the sewage can be evenly distributed to each treatment column. The water outlet tank 6 is located at the bottom of the sand filter tank to collect the treated clean water.

[0028] Preferably, the end of the water inlet pipe 5 is a bell mouth, and a water inlet pump and a water inlet hose are provided on the water inlet pipe 5. The water inlet pump and the water inlet hose are used to pass the sewage in the water inlet pool 4 into the bell mouth at the end of the water inlet pipe 5. The water inlet pump can control the flow rate of the sewage, and the sewage is passed through the water inlet pipe 5 into the first sand filter device 2 for filtration.

[0029] The end of the water inlet pipe 5 is designed to be trumpet-shaped, which helps to expand the water inlet area and enable the sewage to be more evenly distributed into the first sand filter device 2, thereby improving the filtration effect. The water inlet pump is a device installed on the water inlet pipe 5 and is used to control and regulate the flow of sewage entering the sand filter system. By adjusting the operating state of the water inlet pump, the amount of sewage entering the sand filter tank can be controlled, which is very important for maintaining the stable operation of the system. The water inlet hose is used to connect the water source to the water inlet pump and the water inlet pipe 5, providing a flexible connection method for easy maintenance and adjustment. By adjusting the water inlet pump, the flow of sewage entering the sand filter tank can be controlled as needed. This is very critical for maintaining the hydraulic retention time and pressure distribution within the sand filter tank, which in turn affects the filtration effect. The sewage is guided to the first sand filter device 2 through the water inlet pipe 5, where physical filtration and biological treatment begin. The presence of autotrophic denitrification filler 8 helps denitrification occur during the filtration process, thereby reducing the nitrate content in the water.

[0030] Preferably, a flow meter is provided on the water inlet hose, and the flow meter is linked with the water inlet pump to control the water inlet amount. The flow meter is used to monitor the flow of sewage and is linked with the water inlet pump to control the power of the water inlet pump in real time through the flow rate feedback from the flow meter.

[0031] A flow meter installed on the inlet hose accurately measures the flow of wastewater entering the sand filter. This is a crucial monitoring tool, providing real-time visibility into the volume of water flowing into the system. A linkage control mechanism exists between the flow meter and the inlet pump. This means the flow meter not only monitors flow but also sends signals to the inlet pump based on actual flow changes, allowing it to adjust its operating status. This real-time feedback from the flow meter enables the system to adjust the power of the inlet pump in real time. If the flow rate is detected to be below the set point, the system may increase the power of the inlet pump to increase flow; conversely, if the flow rate is too high, the pump power is reduced.

[0032] Preferably, a water storage tank 7 is provided on one side of the top of the overflow weir 3, and the water storage tank 7 is connected to the water inlet of the next sand filter device 2. The filtered clean water overflows through the overflow weir 3 and enters the water storage tank 7. The bottom of the water storage tank 7 is connected to the water inlet of the next sand filter device 2 through the water inlet pipe, so that the clean water can be further filtered to ensure its filtration quality.

[0033] In addition to controlling the direction and speed of the water flow, the overflow weir 3 also serves to guide the filtered clean water to the next treatment step. The water storage tank 7 is designed on one side of the top of the overflow weir to collect the cleaner water filtered after passing through the overflow weir. This water storage tank serves as a temporary storage and transition functional area. The bottom of the water storage tank 7 is connected to the water inlet of the next sand filter device 2 through a pipe. The purpose of this design is to allow the water that has been preliminarily filtered to enter the next sand filter device again for further treatment. Through this design of multiple filtration, the water will undergo multiple filtrations between each sand filter device to ensure that the quality of the final water meets the requirements. This multiple filtration mechanism can significantly improve the overall efficiency and effectiveness of water treatment.

[0034] Preferably, the autotrophic denitrification filler 8 is a composite active biological carrier or a sulfur autotrophic denitrification biological carrier. Composite active biological carriers are typically composed of multiple components and are designed to provide a large surface area for microbial attachment and growth. Composite active biological carriers can support the growth of a variety of microorganisms, not just denitrifying bacteria, but also other microbial communities beneficial to wastewater treatment. These carriers are typically porous, providing a favorable habitat for microorganisms.

[0035] Sulfur-autotrophic denitrifying biofill is specifically designed to support the growth of sulfur-autotrophic denitrifying bacteria. Sulfur-autotrophic denitrification refers to the ability of certain microorganisms to utilize sulfide or other inorganic sulfur compounds as electron donors to carry out denitrification in the absence of an organic carbon source. This filler typically contains sulfur or substances that promote sulfur cycling, creating favorable living conditions for denitrifying bacteria.

[0036] Preferably, the liquid levels in the multiple sand filters 2 in each row are lowered sequentially, forming an overflow level difference. This allows water to flow through the multiple sand filters 2 sequentially for filtration. This improves denitrification efficiency, thereby reducing the nitrate content in the effluent. This reduces the need for external carbon sources and lowers operating costs, thereby improving the overall performance of the sewage treatment plant and enhancing effluent quality.

[0037] The liquid level in each sand filter 2 decreases sequentially. This means that the liquid level in the first row of sand filters is highest, and as the water flows through each filter, the liquid level gradually decreases. When water overflows from one sand filter to the next, the different liquid levels naturally determine the direction of the water flow. Water at higher levels automatically flows to lower levels, ensuring that the water passes through all sand filters in the predetermined order. In this way, wastewater flows through multiple sand filters in sequence, with each filter performing a filter operation. This step-by-step filtration method ensures that impurities in the water are removed in stages, thereby improving the overall filtration effect. Because the water undergoes multiple filtration cycles, each filter helps remove particles of different sizes and types, this method significantly improves the purity of the effluent.

[0038] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention shall be the technical solutions set forth in the claims, including equivalent alternatives to the technical features of the technical solutions set forth in the claims. Equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A filter structure of a sand filter for sewage treatment, characterized by: The invention comprises a sand filter (1), wherein a plurality of columns of sand filter devices (2) are provided in the sand filter (1), an overflow weir (3) is provided between two adjacent sand filter devices (2) in each column, and the sand filter devices (2) are filled with autotrophic denitrification fillers (8); The sand filter (1) is provided with a water inlet pool (4) at the top and a water outlet pool (6) at the bottom. A water inlet pipe (5) is provided in the water inlet pool (4), and the end of the water inlet pipe (5) is connected to the first sand filter device (2) in each column.

2. The filter structure of a sand filter tank for sewage treatment according to claim 1, characterized in that: The end of the water inlet pipe (5) is a bell mouth. A water inlet pump and a water inlet hose are provided on the water inlet pipe (5). The sewage in the water inlet pool (4) is passed into the bell mouth at the end of the water inlet pipe (5) through the water inlet pump and the water inlet hose.

3. The filter structure of a sand filter for sewage treatment according to claim 2, characterized in that: A flow meter is provided on the water inlet hose, and the flow meter is linked with the water inlet pump to control the water inlet volume.

4. The filter structure of a sand filter for sewage treatment according to claim 1, characterized in that: A water storage tank (7) is provided on one side of the top of the overflow weir (3), and the water storage tank (7) is connected to the water inlet of the next sand filter device (2).

5. The filter structure of a sand filter for sewage treatment according to claim 1, characterized in that: The autotrophic denitrification filler (8) is a composite active biological carrier and a sulfur autotrophic denitrification biological filler.

6. The filter structure of a sand filter for sewage treatment according to claim 1, characterized in that: The liquid levels in the multiple sand filter devices (2) in each column are lowered in sequence, forming an overflow liquid level difference.

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