Rainwater collecting, recycling and purifying system and method for chemical production workshop

Abstract

The invention discloses a rainwater collecting, recycling and purifying system for a chemical production workshop, and relates to the technical field of industrial water resource recycling. The system comprises a rainwater collection tank, a sedimentation tank, a quartz sand filter unit, an activated carbon filter unit, an ultrafiltration membrane separation unit and a disinfection water tank which are connected in sequence, and a matched sludge treatment unit and an intelligent control unit. Rainwater is firstly subjected to sedimentation pretreatment after being collected, and then suspended solids, organic matters and microorganisms are removed step by step through a four-stage series purification process; sludge is treated by the frame-plate filter press, and clear liquid flows back to the system; and the controller automatically adjusts operation parameters of each unit based on multi-point water quality monitoring data, so that intelligent regulation and control and safety protection are realized. The problems that the chemical rainwater purification depth is insufficient and the intelligent level is low are solved, safe recycling of rainwater resources is achieved, the effluent COD removal rate reaches 82%, the turbidity removal rate reaches 97%, and the production cost and the environmental load are effectively reduced.

Description

Technical Field

[0001] This invention belongs to the field of industrial water resource recycling technology, and in particular relates to a rainwater collection, reuse and purification system and method for chemical production workshops. Background Technology

[0002] Chemical production processes consume enormous amounts of water. Traditional production workshops rely primarily on fresh water, leading to over-exploitation and waste of water resources and placing high water costs on enterprises. Furthermore, rainwater generated during rainfall in chemical production workshops is often discharged directly without treatment. This rainwater may carry impurities such as dust, oil, and chemical pollutants; direct discharge not only wastes precious water resources but may also pollute the surrounding aquatic environment.

[0003] Existing technologies include some devices specifically designed for rainwater harvesting in chemical plants, but these devices primarily focus on the initial switching, collection, and simple separation of rainwater. Regarding rainwater harvesting and reuse, patent CN117266310A proposes a rainwater recycling device for production workshops, mainly targeting photovoltaic workshops. It achieves rainwater reuse through self-cleaning filters and ultraviolet disinfection units, but lacks deep purification capabilities for complex chemical components and has insufficient intelligent monitoring mechanisms. Patent CN203834561U provides an integrated rainwater harvesting and utilization system, combining a strip-shaped rainwater collection tank with an integrated treatment device. It incorporates processes such as flocculation, sedimentation, filtration, and disinfection, making it suitable for scenarios with limited land. However, its treatment process still relies mainly on conventional physicochemical methods and does not involve deep treatment technologies such as membrane separation, limiting its ability to remove dissolved organic matter and special pollutants that may be present in chemical rainwater.

[0004] In summary, existing rainwater harvesting and reuse systems generally suffer from problems such as limited purification processes, insufficient advanced treatment, low levels of intelligence, and poor adaptability to complex pollutants. They are particularly ill-suited to meeting the high standards for recycled water quality required by chemical production workshops. Therefore, there is an urgent need to develop a rainwater harvesting and reuse purification system suitable for chemical production workshops to achieve safe and efficient reuse of rainwater resources, reduce water costs for enterprises, and mitigate environmental impact. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a rainwater collection and reuse purification system for a chemical production workshop, comprising: a rainwater collection module, including a rainwater collection tank (1) for collecting rainwater from the chemical production workshop; a pretreatment module, including a settling tank (2) for pretreating the rainwater by settling to remove suspended solids; a sludge treatment module, including a sludge tank (3) connected to the sludge outlet of the settling tank (2), and a frame plate filter press (4) connected to the sludge outlet of the sludge tank (3); and a multi-stage deep purification module connected to the sludge outlet of the settling tank (2). The water-end connection includes a quartz sand filtration unit (5), an activated carbon filtration unit (6), an ultrafiltration membrane separation unit (7), and a disinfection unit (8) connected in series. The control and monitoring module includes a controller (9), multiple liquid level sensors, and a water quality monitor. The signal output terminals of the water quality monitor and the liquid level sensors are communicatively connected to the signal input terminals of the controller (9), and the control signal output terminals of the controller (9) are communicatively connected to the drive actuators of the quartz sand filtration unit (5), the activated carbon filtration unit (6), and the ultrafiltration membrane separation unit (7).

[0006] Preferably, the water quality monitoring instrument is installed at least at the outlets of the rainwater collection tank (1), the sedimentation tank (2), the quartz sand filtration unit (5), the activated carbon filtration unit (6), and the disinfection unit (8).

[0007] Preferably, the clear liquid separated by the frame plate filter press (4) is returned to the rainwater collection tank (1) or the sedimentation tank (2).

[0008] Preferably, the water outlet of the disinfection unit (8) is transported to the cooling system, rinsing system or process water point of the chemical production workshop through an independent pipeline network.

[0009] Preferably, the rainwater collection tank (1) is provided with a first rainwater diversion device on the water inlet channel, and the control terminal of the first rainwater diversion device is communicatively connected to the controller (9).

[0010] Preferably, the molecular weight cutoff of the ultrafiltration membrane separation unit (7) is 10 to 100 kDa.

[0011] Preferably, the system is further provided with a first flow meter for monitoring the amount of rainwater collected and a second flow meter for monitoring the amount of rainwater reused after purification, and the signal output terminals of the first flow meter and the second flow meter are communicatively connected to the controller (9).

[0012] The present invention also provides a method for using the above-mentioned rainwater collection and reuse purification system in a chemical workshop. The method includes: a data acquisition step: acquiring water quality data from multiple monitoring points in the system in real time; and a dynamic control step: based on the water quality data, dynamically adjusting the operating parameters of at least one of the quartz sand filtration unit (5), activated carbon filtration unit (6), and ultrafiltration membrane separation unit (7) through a controller (9).

[0013] Preferably, the dynamic control step includes: adjusting the backwashing cycle and intensity based on the turbidity data at the outlet of the quartz sand filter unit (5); predicting and indicating the replacement cycle of activated carbon based on the chemical oxygen demand data at the outlet of the activated carbon filter unit (6); and dynamically adjusting the backwashing frequency and intensity based on the inlet water pressure or product water flow rate data of the ultrafiltration membrane separation unit (7).

[0014] Preferably, the system further includes anomaly monitoring and safety handling steps: continuously comparing the water quality data with preset safety thresholds; when the water quality data at any monitoring point exceeds its corresponding safety threshold, automatically executing at least one of the following safety response operations:

[0015] a) Increase the backwashing intensity of the ultrafiltration membrane separation unit (7) or trigger its chemical cleaning procedure;

[0016] b) Stop supplying water to subsequent purification units and start the internal circulation flushing process of the system;

[0017] c) Lock the final outlet valve to prevent the output of substandard water and trigger an alarm signal for specific pollution indicators.

[0018] Preferably, the system further includes an efficiency assessment step: collecting the total amount of rainwater collected by a first flow meter (F1) and collecting the total amount of purified water reused by a second flow meter (F2); and calculating the water resource reuse rate of the system based on the total amount collected and the total amount of water reused.

[0019] The present invention has the following beneficial effects:

[0020] (1) Deep purification and high water quality stability: The system effectively removes suspended solids, organic matter, microorganisms and other harmful substances from rainwater through a multi-level collaborative deep purification process. The treated water quality can stably meet the standards for reuse in chemical production, ensuring the safety and reliability of the reuse process.

[0021] (2) Intelligent operation and strong system adaptability: Based on the intelligent monitoring and feedback mechanism of the whole process, the system can sense water quality changes in real time and automatically adjust the operating status, effectively cope with water quality fluctuations, improve treatment efficiency and stability, reduce the need for manual intervention, and ensure long-term reliable operation of the system.

[0022] (3) High resource utilization rate and significant comprehensive benefits: While realizing the reuse of rainwater resources, the system effectively treats and recycles the sludge generated during the treatment process, forming a collaborative governance model of water and sludge, significantly improving water resource utilization efficiency, reducing external emissions, and having both good economic and environmental benefits. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a rainwater collection, reuse, and purification system in a chemical production workshop, which is a specific embodiment of the present invention.

[0024] Explanation of reference numerals in the attached diagram: 1. Rainwater collection tank; 2. Sedimentation tank; 3. Sludge tank; 4. Frame plate filter press; 5. Quartz sand filtration unit; 6. Activated carbon filtration unit; 7. Ultrafiltration membrane separation unit; 8. Disinfection unit; 9. Controller; F1. First flow meter; F2. Second flow meter; G1, G2, G3. Rainwater pipe; G4. Sludge pipe; G5. Sludge discharge port; G6. Clear liquid pipe; G7. Clear water pipe; B1. High-pressure pump; B2. Sludge pump; J1, J2, J3, J4, J5. Water quality monitoring instrument; X. Signal transmission route. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings. This embodiment is implemented based on the technical solution of the present invention, and provides detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0026] This invention provides a rainwater collection, reuse, and purification system for a chemical production workshop, such as... Figure 1 As shown, the system mainly includes a rainwater collection tank 1, a sedimentation tank 2, a sludge tank 3, a frame plate filter press 4, a quartz sand filtration unit 5, an activated carbon filtration unit 6, an ultrafiltration membrane 7, a disinfection water tank 8, and a controller 9.

[0027] Rainwater collection tank 1 receives rainwater from the roof and ground of the chemical production workshop via inlet G1 and corresponding rainwater pipes. A flow meter F1 is installed on the inlet pipe of rainwater collection tank 1 to monitor the amount of rainwater flowing into the system in real time. An initial rainwater diversion device is installed at the inlet end of rainwater collection tank 1, which is communicatively connected to controller 9. When the initial rainwater flows through, if the water quality monitor installed in the pipeline detects that the pollutant concentration exceeds a set threshold, controller 9 will activate the diversion device to perform the diversion action, switching the initial rainwater with higher pollution concentration to the sewage network to ensure the water quality of subsequently collected rainwater.

[0028] Sedimentation tank 2 is connected to rainwater collection tank 1 via inlet G2. Its main function is to remove heavier suspended particles from rainwater using the principle of gravity sedimentation. The sludge generated during sedimentation is transported to sludge tank 3 for temporary storage via sludge pipe G4. The sludge in sludge tank 3 then enters frame plate filter press 4 for solid-liquid separation. The separated sludge is discharged from the system through sludge outlet G5 for centralized disposal; while the separated clear liquid is returned to rainwater collection tank 1 or sedimentation tank 2 via clear liquid pipe G6, achieving resource recycling.

[0029] The supernatant, after sedimentation pretreatment, is pumped by high-pressure pump B1 and enters the subsequent multi-stage deep purification process via inlet G3. This process first passes through a quartz sand filter unit 5 to further remove fine suspended solids; then the water flows into an activated carbon filter unit 6, where the activated carbon adsorbs organic matter and odor substances; subsequently, the water flows through an ultrafiltration membrane 7, which effectively traps microorganisms and large organic molecules; finally, the water flows into a disinfection tank 8 for disinfection to kill any remaining bacteria and viruses. The purified water is then transported through a clean water pipe G7 to various reuse points in the chemical production workshop, such as cooling or flushing systems. A flow meter F2 is installed on the reused water pipeline to accurately monitor the amount of purified rainwater reused.

[0030] The intelligent control and monitoring of the system are managed by controller 9. Controller 9 is connected via signal transmission line X to multiple level sensors located in rainwater collection tank 1, sedimentation tank 2, sludge tank 3, and disinfection tank 8, enabling it to automatically control the start and stop of high-pressure pump B1 and sludge pump B2 based on the level information of each tank. In addition, the system is equipped with water quality monitoring instruments at several key nodes, including water quality monitor J1 in rainwater collection tank 1, water quality monitor J2 in sedimentation tank 2, water quality monitor J3 at the outlet of quartz sand filter unit 5, water quality monitor J4 at the outlet of activated carbon filter unit 6, and water quality monitor J5 in disinfection unit 8. These water quality monitors are used to detect key indicators such as chemical oxygen demand (COD), turbidity, and microbial content of water samples in real time.

[0031] Controller 9 receives data from various water quality monitors and dynamically adjusts the operating parameters of relevant purification equipment accordingly, forming an intelligent adaptive control mechanism. Specifically, controller 9 dynamically adjusts the filtration cycle of the quartz sand filter unit 5 based on the turbidity data from water quality monitor J3; it determines the activated carbon adsorption saturation level based on the COD data from water quality monitor J4, thereby adjusting the activated carbon replacement frequency; and it dynamically adjusts the backwashing intensity of the ultrafiltration membrane 7 based on the operating pressure difference or specific water quality indicators. When the reading of any water quality monitor exceeds the preset safety threshold, controller 9 immediately activates the graded safety interlock mechanism. For example, when a serious abnormality in the influent water quality of ultrafiltration membrane 7 is detected, controller 9 may perform one or more of the following operations: a) immediately increase the backwashing intensity of ultrafiltration membrane 7 or trigger its chemical cleaning program; b) stop the influent to activated carbon filter unit 6 or ultrafiltration membrane 7, and simultaneously start the bypass return pipeline of quartz sand filter unit 5 to allow the water to circulate and flush within the system until the water quality returns to normal; c) lock the outlet valve of disinfection tank 8 to completely prevent unqualified water from entering the reuse network, and issue an audible and visual alarm for specific pollution indicators. Monitoring data from flow meters F1 and F2 are also fed back to controller 9 in real time for statistical analysis and efficiency management of system water resource utilization.

[0032] Example

[0033] This embodiment is for a site with an area of ​​8000m² 2 The chemical production workshop is equipped with a standard rainwater collection, reuse, and purification system. Rainwater collection tank 1 is a reinforced concrete structure with a volume of 200 m³. 3 Its inlet G1 connects to the rainwater pipe network of the workshop roof and ground, and is equipped with an initial rainwater diversion device based on electric valves and water quality signals. Sedimentation tank 2 is a rectangular reinforced concrete tank with an effective volume of 150m³. 3 Quartz sand filtration unit 5 uses a pressure-type rapid filter, with quartz sand of a specific particle size as the filter media. Activated carbon filtration unit 6 uses a granular activated carbon filter tank filled with coconut shell activated carbon. Ultrafiltration membrane 7 uses a hollow fiber membrane module, with polyvinylidene fluoride as the membrane material and a molecular weight cutoff of 10,000 Da. Disinfection tank 8 uses a combined ultraviolet light and sodium hypochlorite disinfection method.

[0034] High-pressure pump B1 is a centrifugal pump with specific flow rate and head, while sludge pump B2 is a screw pump. Controller 9 uses a programmable logic controller. The level sensor is a submersible level transmitter. Water quality monitors J1 to J5 are all multi-parameter online detectors capable of detecting COD, turbidity, and microbial content.

[0035] During system operation, controller 9 automatically controls the start and stop of the water pump based on the liquid level and dynamically adjusts the operation of each unit based on real-time water quality data. Practice shows that when J3 detects an abnormal increase in turbidity, the controller not only extends the filtration cycle of the quartz sand filter unit 5 but also enhances its backwashing intensity; when J4 detects a persistently high COD level, the system will issue an early warning to replace the activated carbon. If J5 detects that the final effluent exceeds the standard, the controller will quickly execute the aforementioned safety interlock procedure.

[0036] Based on the monitoring data from the first and second flow meters, controller 9 uses the following calculation formula to determine the rainwater reuse rate of the system:

[0037] Rainwater reuse rate (%) = (Cumulative flow rate of the second flow meter during the monitoring period / Cumulative flow rate of the first flow meter during the monitoring period) × 100%

[0038] The monitoring period can be a daily, monthly, or yearly statistical cycle. The controller has an internal data storage unit that continuously records the total amount of rainwater collected by the first flow meter and the total amount of purified and reused water monitored by the second flow meter.

[0039] After six months of continuous operational testing, the system collected 3200m³ of rainwater during 30 rainfall events. 3 2880m³ was reused after purification treatment. 3 The reuse rate reaches 90%. The purified effluent quality indicators are: average COD 35±8 mg / L (removal rate 82%), average turbidity 5±2 NTU (removal rate 97%), and average microbial content 50±30 CFU / mL (removal rate 99.95%). All indicators are superior to the requirements of the "Design Code for Industrial Circulating Cooling Water Treatment" (GB / T50050-2017). Compared with using fresh water, the company saves approximately 120,000 yuan in water costs annually (based on an industrial water price of 4 yuan / m³). 3 (Calculation). The system's intelligent control response time is less than 30 seconds, the accuracy rate of water quality anomaly identification is 98%, and the success rate of equipment fault early warning is 95%, effectively ensuring the continuity of chemical production. After treatment, the sludge volume is reduced by 70%, and the moisture content is reduced from 95% to 60%, facilitating subsequent disposal. The entire system has a high degree of automation, requiring only one operator to conduct inspections twice a week, significantly reducing labor costs.

[0040] The above description is a preferred embodiment of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A rainwater collection, reuse, and purification system for a chemical production workshop, characterized in that, include: Rainwater harvesting module, including rainwater harvesting tank (1), for collecting rainwater from chemical production workshop; The pretreatment module includes a settling tank (2) for pre-treating rainwater by settling to remove suspended solids; The sludge treatment module includes a sludge tank (3) connected to the sludge outlet of the settling tank (2), and a frame plate filter press (4) connected to the sludge outlet of the sludge tank (3). The multi-stage deep purification module is connected to the outlet of the sedimentation tank (2) and includes a quartz sand filtration unit (5), an activated carbon filtration unit (6), an ultrafiltration membrane separation unit (7) and a disinfection unit (8) connected in series. The control and monitoring module includes a controller (9), multiple liquid level sensors and a water quality monitor; the signal output terminals of the water quality monitor and the liquid level sensors are communicatively connected to the signal input terminal of the controller (9), and the control signal output terminal of the controller (9) is communicatively connected to the drive execution components of the quartz sand filtration unit (5), the activated carbon filtration unit (6) and the ultrafiltration membrane separation unit (7).

2. The rainwater harvesting and reuse purification system according to claim 1, characterized in that, The water quality monitoring instrument is installed at least at the outlets of the rainwater collection tank (1), sedimentation tank (2), quartz sand filtration unit (5), activated carbon filtration unit (6), and disinfection unit (8).

3. The rainwater harvesting and reuse purification system according to claim 1, characterized in that, The clear liquid separated by the frame plate filter press (4) is returned to the rainwater collection tank (1) or sedimentation tank (2).

4. The rainwater harvesting and reuse purification system according to claim 1, characterized in that, The water outlet of the disinfection unit (8) is transported to the cooling system, rinsing system or process water point of the chemical production workshop through an independent pipeline network.

5. The rainwater harvesting and reuse purification system according to claim 1, characterized in that, The rainwater collection tank (1) is equipped with a first rainwater diversion device on its inlet channel, and the control terminal of the first rainwater diversion device is communicatively connected to the controller (9).

6. The rainwater harvesting and reuse purification system according to claim 1, characterized in that, The ultrafiltration membrane separation unit (7) has a molecular weight cutoff of 10 to 100 kDa.

7. The rainwater harvesting and reuse purification system according to claim 1, characterized in that, The system is also equipped with a first flow meter for monitoring the amount of rainwater collected and a second flow meter for monitoring the amount of rainwater reused after purification. The signal output terminals of the first flow meter and the second flow meter are communicatively connected to the controller (9).

8. A method for using the rainwater collection, reuse, and purification system for a chemical workshop as described in any one of claims 1 to 7, characterized in that, The method includes: Data acquisition steps: Real-time acquisition of water quality data from multiple monitoring points in the system; Dynamic control steps: Based on the water quality data, the operating parameters of at least one of the quartz sand filtration unit (5), activated carbon filtration unit (6) and ultrafiltration membrane separation unit (7) are dynamically adjusted by the controller (9).

9. The method according to claim 8, characterized in that, The dynamic control steps include: Adjust the backwashing cycle and intensity based on the turbidity data at the outlet of the quartz sand filter unit (5); Based on the chemical oxygen demand data at the outlet of the activated carbon filter unit (6), the replacement cycle of the activated carbon is predicted and indicated. The frequency and intensity of backwashing are dynamically adjusted based on the inlet pressure or product water flow rate data of the ultrafiltration membrane separation unit (7).

10. The method according to claim 8, characterized in that, It also includes anomaly monitoring and security handling procedures: The water quality data is continuously compared with a preset safety threshold. When the water quality data at any monitoring point exceeds its corresponding safety threshold, at least one of the following safety response actions will be automatically executed: a) Increase the backwashing intensity of the ultrafiltration membrane separation unit (7) or trigger its chemical cleaning procedure; b) Stop supplying water to subsequent purification units and start the internal circulation flushing process of the system; c) Lock the final outlet valve to prevent the output of substandard water and trigger an alarm signal for specific pollution indicators.

11. The method according to claim 8, characterized in that, It also includes an efficiency assessment step: collecting the total amount of rainwater collected by the first flow meter (F1) and collecting the total amount of purified water reused by the second flow meter (F2); and calculating the water resource reuse rate of the system based on the total amount collected and the total amount of water reused.

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