Treatment device for wastewater from a sludge alkaline thermal hydrolysis process

Abstract

The utility model relates to sewage treatment technical field especially a kind of processing device of sludge alkaline hydrolysis process waste water, it can waste water non-compliance, land is nervous and the problem of low resource utilization, it includes the MVR evaporation condensate film processing unit of connecting MVR evaporation equipment, the plate frame cleaning water processing unit of connecting sludge dewatering equipment and comprehensive pool unit, MVR evaporation condensate film processing unit includes cooling tower, plate heat exchanger, MVR condensate regulating pool and reverse osmosis membrane separation system connected in turn, reverse osmosis membrane separation system connects scale inhibitor dosing device and non-oxidizing bactericide dosing device, plate frame cleaning water processing unit includes water collecting pool, primary sedimentation tank, plate frame cleaning water regulating pool, three-stage reaction tank, efficient sedimentation tank and sludge concentration tank connected in turn, sludge concentration tank is also connected primary sedimentation tank and plate frame cleaning water regulating pool, three-stage reaction tank connects PAC dosing device, PAM dosing device and sodium carbonate dosing device.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology, and in particular to a treatment device for wastewater generated by alkaline hot water hydrolysis of sludge, which is applicable to the treatment of production wastewater in municipal sludge treatment plants. Background Technology

[0002] The sludge alkaline hot water hydrolysis process consists of sludge hot water hydrolysis + plate and frame filter press + MVR evaporation and concentration process. Municipal sludge is subjected to alkaline hot water hydrolysis and then filtered. The sludge residue from the filter press is transported off-site, while the filtrate is entered into the MVR equipment for evaporation, and the concentrated liquid becomes a resource-based product. The alkaline hot water hydrolysis process for sludge generates two typical types of wastewater: one is MVR evaporation condensate, which has high COD (approximately 2000 mg / L), high NH3-N (approximately 167 mg / L), low calcium and magnesium ion concentration, low salinity, low SS, and few impurities. In actual operation, the quality of the evaporation condensate differs significantly from the design values ​​and fluctuates considerably. The other type is plate and frame filter press cleaning water. The alkaline hot water hydrolysis process for sludge uses a plate and frame filter press to dewater the hydrolyzed sludge. The filter cloth of the filter press needs to be cleaned regularly, and the cleaning water has high COD (approximately 2000 mg / L), high SS content (approximately 1800 mg / L), and high calcium ion content (approximately 497 mg / L), with complex composition. In actual operation, the volume of plate and frame filter press cleaning water is large, limiting the production load.

[0003] The existing processing system has many shortcomings: Wastewater quality fluctuates greatly, and traditional treatment processes are unable to achieve stable compliance with municipal sewer standards. Most sludge treatment plants face land shortages, and traditional biological processes require large land areas and are difficult to construct, making them unsuitable for renovation projects. At the same time, there is a lack of effective resource reuse designs, resulting in water waste. Summary of the Invention

[0004] To address the aforementioned technical problems, this utility model provides a wastewater treatment device for sludge alkaline hot water hydrolysis processes, which can solve the problems of wastewater failing to meet standards, limited land use, and low resource utilization.

[0005] The technical solution is as follows: a treatment device for wastewater generated by sludge alkaline hot water hydrolysis process, characterized in that it includes an MVR evaporation condensate membrane treatment unit connected to an MVR evaporation device, a plate and frame cleaning water treatment unit connected to a sludge dewatering device, and a comprehensive water tank unit. The MVR evaporation condensate membrane treatment unit includes a cooling tower, a plate heat exchanger, an MVR condensate conditioning tank, and a reverse osmosis membrane separation system connected in sequence. The reverse osmosis membrane separation system is connected to an antiscalant dosing device and a non-oxidizing bactericide dosing device. The plate and frame cleaning water treatment unit includes a collection tank, a primary sedimentation tank, a plate and frame cleaning water conditioning tank, a tertiary reaction tank, a high-efficiency sedimentation tank, and a sludge thickening tank connected in sequence. The sludge thickening tank is also connected to the primary sedimentation tank and the plate and frame cleaning water conditioning tank. The tertiary reaction tank is connected to a PAC dosing device, a PAM dosing device, and a sodium carbonate dosing device.

[0006] A further feature is that the integrated water tank unit includes a PB return tank, a product water tank, and a concentrate tank; the reverse osmosis membrane separation system connects the product water tank and the concentrate tank; the high-efficiency sedimentation tank is connected to the product water tank through the PB return tank; the concentrate tank is used to collect the concentrate produced by the reverse osmosis membrane separation system and reuse it in the lime slurry preparation process; the product water tank is used to collect the treated MVR evaporation condensate and plate and frame cleaning water, which are mixed with other low-concentration direct discharge wastewater in the workshop and discharged in compliance with standards.

[0007] By adopting this utility model, a differentiated treatment approach is used, matching specific processes to different wastewater characteristics. The MVR condensate uses a reverse osmosis membrane separation system to accurately remove dissolved pollutants, while the plate and frame filter press cleaning water uses a sedimentation system to efficiently remove suspended pollutants and calcium ions. The process is highly targeted, with high wastewater treatment efficiency and guaranteed treatment quality. The structure is compact and saves floor space. Furthermore, the concentrated water from the reverse osmosis membrane separation system can be reused for lime slurry preparation, and the settled sludge from the sludge thickening tank enters the plate and frame filter press sludge feed tank for treatment. The concentrated sludge can be returned to the plate and frame filter press system, reducing water waste and sludge disposal costs, and improving resource utilization. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the system of this utility model; Figure 2 These are the water quality indicators for the effluent after treatment by the system of this utility model. Detailed Implementation

[0009] See Figure 1As shown, a wastewater treatment device for sludge alkaline hot water hydrolysis process includes an MVR evaporation condensate membrane treatment unit connected to MVR evaporation equipment 1, a plate and frame cleaning water treatment unit connected to sludge dewatering equipment 2, and a comprehensive water tank unit. The MVR evaporation condensate membrane treatment unit includes a cooling tower 3, a plate heat exchanger 4, an MVR condensate equalization tank 5, and a reverse osmosis membrane separation system 6 connected in sequence. The reverse osmosis membrane separation system 6 is connected to an antiscalant dosing device 7 and a non-oxidizing bactericide dosing device 8. The reverse osmosis membrane separation system 6 uses antifouling membrane modules, and the system recovery rate is ≥75%, with a COD of 100%. The removal rate is ≥90%, and the NH3-N removal rate is ≥85%. The plate and frame cleaning water treatment unit includes a collection tank 9, a primary sedimentation tank 10, a plate and frame cleaning water equalization tank 11, a tertiary reaction tank 12, a high-efficiency sedimentation tank 13, and a sludge thickening tank 14 connected in sequence. The sludge thickening tank 14 is also connected to the primary sedimentation tank 10 and the plate and frame cleaning water equalization tank 11. The primary sedimentation tank 10 and the high-efficiency sedimentation tank 13 discharge sludge to the sludge thickening tank 14. The sludge supernatant in the sludge thickening tank 14 is sent to the plate and frame cleaning water equalization tank 11 to achieve reasonable sludge disposal. The tertiary reaction tank 12 is connected to a PAC dosing device, a PAM dosing device, and a sodium carbonate dosing device. After coagulation and sedimentation, the COD removal rate of the plate and frame cleaning water treatment unit can reach 50%, and the ammonia nitrogen basically meets the discharge standards after sedimentation.

[0010] The integrated water tank unit includes a PB return tank 15, a product water tank 16, and a concentrate tank 17. The reverse osmosis membrane separation system 6 connects the product water tank 16 and the concentrate tank 17. The high-efficiency sedimentation tank 13 is connected to the product water tank 16 through the PB return tank 18, and acid is introduced into the PB return tank 18. The concentrate tank 17 is used to collect the concentrate produced by the reverse osmosis membrane separation system and reuse it in the lime slurry preparation process. The product water tank 16 is used to collect the treated MVR evaporation condensate and plate and frame cleaning water, which are mixed with other low-concentration direct discharge wastewater in the workshop and discharged after meeting the standards.

[0011] The MVR evaporative condensate membrane treatment unit adopts a "cooling system + RO system" treatment process. First, the MVR evaporative condensate is cooled to 25°C through a cooling tower and plate heat exchanger to avoid high temperature damage to the membrane module. Then, it enters the reverse osmosis membrane separation system. This membrane module adopts an anti-fouling design and can efficiently remove pollutants such as COD and NH3-N, with a wastewater recovery rate of ≥75%. The supporting chemical dosing system adds scale inhibitors, reducing agents, and bactericides to ensure the stable operation of the membrane system.

[0012] The plate and frame filter press cleaning water treatment unit adopts a "primary sedimentation + chemical dosing high-efficiency sedimentation" treatment process. The plate and frame filter press cleaning water first enters the primary sedimentation tank for gravity sedimentation to remove a large amount of suspended sludge; then it enters the high-efficiency sedimentation tank, where PAC, PAM and sodium carbonate are added to achieve deep removal of SS, calcium ions and COD; the settled sludge finally enters the sludge thickening tank, and the thickened sludge is returned to the plate and frame filter press system to achieve proper sludge disposal.

[0013] The equalization tank is used to buffer fluctuations in water quality and quantity, ensuring the stable operation of subsequent treatment units; The system described in this application has been applied to the first phase of the company's sludge project's wastewater upgrading and renovation project. The project site is located within the Taiyuan Circular Economy Environmental Sanitation Industry Demonstration Base. The treatment capacity is 600 m³ / d of MVR evaporation condensate and 160 m³ / d of plate and frame cleaning water. The device is integrated into the existing solid fertilizer workshop, and the cooling tower is located in the green space north of the workshop.

[0014] Water quality data during the commissioning and operation of this device are as follows: Figure 2 As shown.

[0015] The above commissioning and operation data show that the device has stable treatment effect and strong shock resistance in actual operation. After treatment by the RO system, the COD and ammonia nitrogen removal rates of the MVR evaporation condensate both exceed the design requirements; the plate and frame cleaning water is treated by the sedimentation unit, and the suspended solids are thoroughly removed, effectively mitigating the risk of scaling. The final mixed effluent from the two treated wastewater streams consistently exceeds the Class A limits of the "Water Quality Standard for Wastewater Discharge into Urban Sewerage Systems" (GB / T 31962-2015), achieving stable compliance with discharge standards.

[0016] This application, through modular design, not only achieves stable and compliant wastewater treatment, but also makes full use of existing facilities, reducing engineering investment and operating costs, and has good practicality and promotional value.

Claims

1. A treatment device for wastewater generated from an alkaline hot water hydrolysis process of sludge, characterized in that, It includes an MVR evaporation condensate membrane treatment unit connected to an MVR evaporation device, a plate and frame cleaning water treatment unit connected to a sludge dewatering device, and a comprehensive water tank unit. The MVR evaporation condensate membrane treatment unit includes a cooling tower, a plate heat exchanger, an MVR condensate equalization tank, and a reverse osmosis membrane separation system connected in sequence. The reverse osmosis membrane separation system is connected to an antiscalant dosing device and a non-oxidizing bactericide dosing device. The plate and frame cleaning water treatment unit includes a collection tank, a primary sedimentation tank, a plate and frame cleaning water equalization tank, a tertiary reaction tank, a high-efficiency sedimentation tank, and a sludge thickening tank connected in sequence. The sludge thickening tank is also connected to the primary sedimentation tank and the plate and frame cleaning water equalization tank. The tertiary reaction tank is connected to a PAC dosing device, a PAM dosing device, and a sodium carbonate dosing device.

2. The treatment device for wastewater generated by the alkaline hot water hydrolysis process of sludge according to claim 1, characterized in that, The integrated water tank unit includes a PB return tank, a product water tank, and a concentrate tank. The reverse osmosis membrane separation system connects the product water tank and the concentrate tank. The high-efficiency sedimentation tank is connected to the product water tank through the PB return tank. The concentrate tank is used to collect the concentrate produced by the reverse osmosis membrane separation system and reuse it in the lime slurry preparation process; the product water tank is used to collect the treated MVR evaporation condensate and plate and frame cleaning water, which are mixed with other low-concentration direct discharge wastewater in the workshop and discharged in compliance with standards.

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