A dry powder medicament direct injection type sewage treatment device

Abstract

The utility model discloses a kind of dry powder medicament direct injection type sewage treatment devices belonging to industrial sewage treatment technical field, including pry dress box, dosing pry dress box and PLC control cabinet, sludge dewatering unit is equipped in upper pry dress box, air floatation unit is equipped in lower pry dress box, ton bag feeding station is equipped in dosing pry dress box;Sludge dewatering unit includes efficient flocculation mixing device, string screw sludge dewatering machine, vacuum feeding machine and screw conveyor, air floatation unit includes dissolved air tank, efficient dissolved air floatation tank, air compressor, dreg tank and clean water tank.The utility model discloses a kind of dry powder medicament direct injection type sewage treatment devices, structure design is reasonable, not only simplify process link, reduce energy consumption and maintenance amount, equipment floor area is also significantly reduced, promote space utilization, realized the organic combination of dry powder medicament direct addition and automatic intelligent control, make dosing process more efficient, stable and energy saving, entire system realizes from dosing, reaction, dewatering to the whole process automation of purification, significantly reduce operating cost and artificial intensity.

Description

Technical Field

[0001] This utility model belongs to the field of industrial wastewater treatment technology, and mainly relates to a wastewater treatment device for direct dosing of dry powder reagents. Background Technology

[0002] Currently, coagulation and flocculation are the most common and widely used physicochemical treatment methods in wastewater treatment. Conventional treatment typically employs a combination of polyaluminum chloride (PAC) and polyacrylamide (PAM) to achieve preliminary purification of wastewater through coagulation and sedimentation of suspended solids, emulsified oil, and organic pollutants. However, when dealing with complex water qualities such as oilfield produced water, desalination wastewater, and chemical wastewater that are high in oil content, high in salinity, and highly volatile, traditional processes have significant shortcomings. First, the reagents need to be dissolved and diluted before they can be added and used. It also requires the configuration of a dissolving tank, a stirring device and a storage tank, which results in a large system size, complex structure and large footprint, which is not conducive to equipment integration and skid-mounted layout. At the same time, the dissolving process consumes a lot of water and is cumbersome to operate, which violates the concept of energy and water conservation. Secondly, in conventional wastewater flocculation treatment, the chemicals used must first undergo a maturation process, that is, the chemicals must be fully dissolved in water at a certain ratio before they can be added to the wastewater through a metering pump for mixing and reaction. This process not only consumes a large amount of water and electricity, but also has relatively cumbersome operation steps; Third, traditional dosing methods mostly use fixed-ratio metering pumps for dosing, which have a low degree of automation and cannot automatically adjust the dosing amount according to real-time water quality fluctuations. This can easily lead to waste of chemicals or insufficient dosing, affecting treatment stability and effluent quality. Fourth, conventional flocculants have limited adaptability. Under conditions of high salt, high oil, or complex organic matter, the floc structure is loose, the settling performance is poor, the dewatering performance is poor, and the sludge is easily broken and lost, leading to an increase in the dewatering load. Fifth, the overall system has poor skid-mounted integration, making it difficult to meet the needs of rapid deployment and flexible operation in oilfield well sites, mobile stations, or space-constrained locations.

[0003] To address the aforementioned shortcomings, those skilled in the art have developed a dry powder agent for wastewater treatment, as described in Chinese Patent Publication No. CN116239733A, entitled "A Flocculation Complex for Wastewater Treatment and Its Preparation Method." This agent has advantages such as not relying on water for dissolving the agent and being able to be directly added as a dry powder. Therefore, this application has developed an integrated wastewater treatment device that can automatically control the dosage based on real-time water quality, in order to achieve a highly efficient, energy-saving, automated, and modular integrated wastewater treatment solution.

[0004] Furthermore, the existing wastewater treatment process employs an air flotation-scum-dewatering process. However, this process has several drawbacks. When the suspended solids concentration in the wastewater is high (SS > 3000 mg / L), direct entry into the air flotation unit leads to reduced collision and encapsulation efficiency between bubbles and particles. The resulting scum layer is also excessively concentrated and loosely structured, affecting not only the flotation separation effect but also causing short-circuiting and foam accumulation within the flotation tank. Under high load operation, the equipment requires frequent scum removal, resulting in poor operational stability and significant fluctuations in treated water quality. Simultaneously, the scum produced by air flotation has a high water content and large sludge volume, increasing the load on subsequent dewatering equipment and requiring increased reagent dosage and dewatering energy consumption. Overall, this process reduces the separation efficiency of air flotation and increases the difficulty of sludge dewatering, hindering the continuous and stable operation of the system and the consistent achievement of effluent standards. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings of the prior art and provide a wastewater treatment device for direct dosing of dry powder reagents.

[0006] This utility model discloses a direct-injection wastewater treatment device for dry powder chemicals, suitable for treating wastewater with dry powder chemicals. It comprises two vertically fixed skid-mounted housings, a dosing skid-mounted housing on one side of the lower skid-mounted housing, and a PLC control cabinet. A sludge dewatering unit is located in the upper skid-mounted housing, and an air flotation unit is located in the lower skid-mounted housing. A ton-bag feeding station is located within the dosing skid-mounted housing. The sludge dewatering unit includes a high-efficiency flocculation mixing device, a screw conveyor sludge dewatering machine, a vacuum feeder, and a screw conveyor. The air flotation unit includes a dissolved air tank, a high-efficiency dissolved air flotation tank, an air compressor, a scum tank, and a clear water tank. The outlet of the ton-bag feeding station is connected to the inlet of the vacuum feeder via a pipeline. The outlet of the vacuum feeder is connected to the inlet of the screw conveyor. The outlet of the screw conveyor is located above the dry powder inlet above the inlet of the high-efficiency flocculation mixing device. The wastewater inlet of the coagulation mixing device is connected to the feed pipe a, and the outlet is connected to the feed inlet of the screw sludge dewatering machine via a pipe. A sludge screw conveyor is installed at the outlet of the screw sludge dewatering machine. The filtrate outlet of the screw sludge dewatering machine is connected to the liquid inlet of the high-efficiency dissolved air flotation tank via pipe b. The air outlet of the air compressor is connected to the air inlet of the dissolved air tank via a pipe. The dissolved air water outlet of the dissolved air tank is connected to the dissolved air water inlet of the high-efficiency dissolved air flotation tank via a pipe. The slag outlet A of the high-efficiency dissolved air flotation tank is connected to the feed inlet of the slag box via a pipe, and the liquid outlet B is connected to the liquid inlet of the clear water tank via a pipe. The sewage outlet of the slag box is connected to the slag inlet of the high-efficiency flocculation mixing device via pipe c. Two water outlets are provided at the bottom of the clear water tank. One water outlet is connected to the water inlet of the dissolved air tank via pipe d, and the other water outlet is connected to the external discharge pipeline e.

[0007] As a further improvement of this utility model, the high-efficiency flocculation mixing device includes a rectangular box body with multiple support legs at the bottom. Vertically upward partitions I and vertically downward partitions II are fixedly spaced on the bottom and top plates of the box body, dividing the interior of the box body into multiple processing chambers. A variable frequency reducer is installed above each processing chamber. The output shaft of each variable frequency reducer passes through the box body and is placed inside it, with a rotating rod fixed at its end. The lower end of each rotating rod is rotatably connected to the bottom plate of the box body. A stirring blade is provided on the outer wall of each rotating rod. The box body has a dry powder inlet above the feed end, one or more exhaust outlets on the top plate of the box body, a sewage inlet and a scum inlet on the side wall of the feed end of the box body, and a discharge outlet on the side wall of the discharge end; a cyclone premixer is provided on the inner wall of the box body at the sewage inlet and is connected to the sewage inlet. The upper inlet of the cyclone premixer corresponds to the lower outlet of the dry powder inlet. The sewage pumped out by the raw material pump forms a strong vortex turbulence in the cyclone premixer. The dry powder agent comes into contact with the sewage and quickly dissolves together, flowing out from the bottom of the cyclone premixer with stirring.

[0008] As a further improvement of this utility model, the partition I and partition II divide the box body into three processing chambers from the feeding end to the discharging end. The speed of the first-stage variable frequency reducer in the three processing chambers is 80-120 rpm, the speed of the second-stage variable frequency reducer is 60-80 rpm, and the speed of the third-stage variable frequency reducer is 40-60 rpm. A manhole is provided at the upper end of each of the three processing chambers, and a cover is provided on each of the three manholes.

[0009] As a further improvement of this utility model, the upper end of the partition I is left with a gap from the top plate of the box, and the bottom end of the partition II is left with a gap from the bottom plate of the box, so that the sewage flows in a serpentine manner in the box, and the combination time of the sewage and the dry powder agent is 10 to 20 minutes.

[0010] As a further improvement of this utility model, the cyclone premixer is composed of a spiral blade fixed inside a shell. The shell is composed of a conical cylinder fixed at the lower end of a cylindrical cylinder. One end of the sewage inlet is connected to the upper side wall of the cylindrical cylinder and is positioned above the spiral blade. A mixed liquid outlet is provided at the bottom end of the conical cylinder.

[0011] As a further improvement of this utility model, the device also includes an exhaust gas purification device, wherein the exhaust gas outlets of the high-efficiency flocculation mixing device, the screw conveyor sludge dewatering machine, the high-efficiency dissolved air flotation tank, the scum box and the clear water tank are respectively connected to the air inlet of the exhaust gas purification device through pipelines.

[0012] As a further improvement of this utility model, an electric two-way valve, a raw material pump, an electromagnetic flowmeter I, a pH transmitter I, and an online turbidity meter III are provided on the feed pipeline a; an online turbidity meter I is provided on the pipeline b; a scum pump is provided on the pipeline c; a dissolved air pump is provided on the pipeline d; and a clean water export pump, a pH transmitter II, an online turbidity meter II, and an electromagnetic flowmeter II are provided on the pipeline e.

[0013] As a further improvement of this utility model, the PLC control cabinet is electrically connected to the electric two-way valve, the raw material pump, the electromagnetic flowmeter I, the pH transmitter I, the online turbidity meter III, the online turbidity meter I, the scum pump, the dissolved air pump, the clean water export pump, the pH transmitter II, the online turbidity meter II, and the electromagnetic flowmeter II, respectively.

[0014] This utility model discloses a direct-dosing wastewater treatment device using dry powder reagents. It features a rational structural design, employing a double-layered, stacked skid-mounted design. Gravity-driven flow allows for natural connection between filtrate and flotation, while high-level sludge discharge optimizes sludge cake collection. This simplifies the process, reduces energy consumption and maintenance, significantly decreases equipment footprint, and improves space utilization. Through direct dry powder dosing technology, pH sensor-based feedback control, and a modular skid-mounted structure, it organically combines direct dry powder reagent dosing with automated intelligent control, making the dosing process more efficient, stable, and energy-saving. The overall equipment volume is reduced by more than 40%, and the reagent dosing accuracy is improved to ±5%. The system operates without the need for dissolving the reagent in water, saving thousands of tons of water annually. The resulting flocs are dense and settle quickly, increasing the clarity of the filtrate by 30% after dewatering, and maintaining an effluent compliance rate of over 95%. The entire system achieves full automation from dosing, reaction, dewatering to purification, significantly reducing operating costs and labor intensity, making it worthy of widespread application. Attached Figure Description

[0015] Figure 1 This is a process flow diagram of the present invention; Figure 2 This is a cross-sectional view of the high-efficiency flocculation mixing device of this utility model; Figure 3 This is a top view of the high-efficiency flocculation mixing device of this utility model; Figure 4 This is a diagram showing the layout of the experimental setup at the site. Detailed Implementation

[0016] This utility model discloses a direct-dosing wastewater treatment device for dry powder reagents, which is suitable for treating wastewater with dry powder reagents. It consists of two skid-mounted boxes fixed at opposite ends, a dosing skid-mounted box on one side of the lower skid-mounted box, and a PLC control cabinet. Specifically, the lower skid-mounted box and the dosing skid-mounted box are arranged side by side, and an upper skid-mounted box is fixed on the lower skid-mounted box and the dosing skid-mounted box.

[0017] The upper skid-mounted housing houses a sludge dewatering unit, which includes a high-efficiency flocculation mixing device 4, a screw conveyor 5, a vacuum feeder 2, and a screw conveyor 3. The lower skid-mounted housing houses an air flotation unit, which includes a dissolved air tank 6, a high-efficiency dissolved air flotation tank 7, an air compressor 8, a scum tank 9, and a clear water tank 10. The entire equipment adopts a "double-layer stacked skid-mounted design," with the screw conveyor sludge dewatering unit on the upper layer and the air flotation unit on the lower layer. This compact structure and rational functional integration offer significant technological and operational advantages. This arrangement allows the filtrate from the upper dewatering unit to flow directly into the lower air flotation unit by gravity, eliminating the need for a high-lift volumetric pump. This avoids increased energy consumption and the problem of floc shearing damage during filtrate transport, thus ensuring floc integrity and improving air flotation separation efficiency and effluent stability. Simultaneously, the high-level arrangement of the dewatering unit facilitates the direct collection of sludge cake into vehicles or ton bags, making operation convenient and efficient.

[0018] The dosing skid-mounted box is equipped with a ton bag feeding station 1. The outlet of the ton bag feeding station 1 is connected to the inlet of the vacuum feeder 2 through a pipeline. The outlet of the vacuum feeder 2 is connected to the inlet of the screw conveyor 3. The outlet of the screw conveyor 3 is located at the dry powder inlet 24 above the feed end of the high-efficiency flocculation mixing device 4. After the dry powder agent is sucked into the hopper by the vacuum feeder 2, it is quantitatively transported to the flocculation mixing device by the screw conveyor 3. The dosage is precisely controlled by the screw variable frequency motor 41 of the screw conveyor 3. A weight sensor 42 is installed at the bottom of the hopper of the vacuum feeder 2 to ensure that the agent and the sewage react fully in the high-efficiency mixing zone to form uniform flocs.

[0019] The wastewater inlet 11 of the high-efficiency flocculation mixing device 4 is connected to the feed pipe a, and the outlet 12 is connected to the feed inlet of the screw sludge dewatering machine 5 through a pipe. The feed pipe a is equipped with an electric two-way valve 28, a raw material pump 29, an electromagnetic flowmeter I 30, a pH transmitter I 31, and an online turbidity meter III 43. The sludge screw conveyor 13 is provided at the outlet of the screw sludge dewatering machine 5. The filtrate outlet of the screw sludge dewatering machine 5 is connected to the liquid inlet of the high-efficiency dissolved air flotation tank 7 through a pipe b, and an online turbidity meter I 32 is provided on the pipe b.

[0020] The air outlet of the air compressor 8 is connected to the air inlet of the dissolved air tank 6 via a pipeline. The dissolved air water outlet of the dissolved air tank 6 is connected to the dissolved air water inlet of the high-efficiency dissolved air flotation tank 7 via a pipeline. In the high-efficiency dissolved air flotation tank 7, the filtrate comes into contact with the air-water mixture (dissolved air water) from the dissolved air tank 6. The dissolved air water is drawn from the clear water tank by the dissolved air pump, pressurized and mixed with air in the dissolved air tank to form a high-concentration air-water mixture, which is then introduced into the bottom of the flotation tank through the dissolved air water pipeline, causing the fine suspended matter in the water to be lifted by the air bubbles to form a scum layer; the upper part of the high-efficiency dissolved air flotation tank 7... The device is equipped with a scum scraping mechanism. The scum from the high-efficiency dissolved air flotation tank 7 is collected by the scum scraping mechanism and flows by gravity from the scum outlet A into the scum tank 9 through the scum scraping trough. The clean water flows into the clean water tank 10 through the liquid outlet B. The sewage outlet of the scum tank 9 is connected to the scum inlet 14 of the high-efficiency flocculation mixing device 4 through a pipeline c, and a scum pump 33 is installed on the pipeline c. After the scum in the scum tank 9 is homogenized by the agitator, it is pumped back to the scum inlet 14 of the high-efficiency flocculation mixing device 4 through the scum pump 33 from the discharge outlet of the scum tank 9, realizing scum return and circulation treatment.

[0021] The lower part of the clear water tank 10 is provided with two water outlets. One water outlet is connected to the water inlet of the dissolved air tank 6 through pipe d, and the other water outlet is connected to the external discharge pipeline e. A dissolved air pump 34 is provided on the pipe d, and a clear water external discharge pump 35, a pH transmitter II 36, an online turbidity meter II 37, and an electromagnetic flow meter II 38 are provided on the external discharge pipeline e.

[0022] The PLC control cabinet is electrically connected to the electric two-way valve 28, raw material pump 29, electromagnetic flowmeter I 30, pH transmitter I 31, online turbidity meter III 43, online turbidity meter I 32, scum pump 33, dissolved air pump 34, clean water export pump 35, pH transmitter II 36, online turbidity meter II 37, and electromagnetic flowmeter II 38, respectively.

[0023] The high-efficiency flocculation mixing device 4 includes a rectangular box 15. Multiple support legs 16 are provided at the bottom of the box 15. Vertically upward partitions I 17 and vertically downward partitions II 18 are fixed at intervals on the bottom and top plates of the box 15. A gap is left between the upper end of partition I 17 and the top plate of the box 15, and a gap is left between the bottom end of partition II 18 and the bottom plate of the box 15. Both ends of partitions I 17 and II 18 are flush with the front and rear side walls of the box 15. The fixed partitions I 17 and II 18 cause the wastewater to flow in a serpentine pattern within the tank 15, ensuring that the wastewater and dry powder reagent combine within 10-20 minutes. The partitions I 17 and II 18 divide the interior of the tank 15 into three processing chambers from the inlet to the outlet. Above each of the three processing chambers is a primary variable frequency drive 19, a secondary variable frequency drive 20, and a tertiary variable frequency drive 21, respectively. The primary variable frequency drive 19 operates at a speed of 100... The speed of the two-stage variable frequency reducer 20 is 70 rpm, and the speed of the three-stage variable frequency reducer 21 is 50 rpm. The output shaft of each variable frequency reducer passes through the housing 15 and is placed inside it, with a rotating rod 22 fixed at its end. The lower end of each rotating rod 22 is rotatably connected to the bottom plate of the housing 15. A stirring blade 23 is provided on the outer wall of each rotating rod 22. A dry powder inlet 24 is provided above the feed end of the housing 15. One or more exhaust gas outlets 25 are provided on the top plate of the housing 15. A sewage inlet 11 and a scum inlet 14 are provided on the side wall of the feed end of the housing 15, and an outlet 12 is provided on the side wall of the discharge end. A cyclone premixer 39 is installed on the inner wall of the housing 15 at location 11 and is connected to the sewage inlet 11. The upper inlet of the cyclone premixer 39 corresponds to the lower outlet of the dry powder feed inlet 24. The sewage pumped by the raw material pump 29 forms a strong vortex turbulence in the cyclone premixer 39. The dry powder agent dissolves rapidly after contacting the sewage and flows out from the bottom of the cyclone premixer 39 with stirring. This effectively prevents the sewage that has just come into contact with the agent from entering the second chamber, so that every drop of water can complete a serpentine flow and meet the flocculation mixing time requirements. Manholes 40 are provided at the upper ends of the three treatment chambers, and each of the three manholes 40 is equipped with a cover. This device allows the compounded dry powder agent to be directly mixed with sewage without prior maturation. The dry powder agent and sewage react fully in the high-efficiency flocculation mixing device after extended stirring time to complete the flocculation process, achieving rapid dispersion and efficient mixing of the agent.

[0024] The cyclone premixer 39 is constructed by fixing helical blades to the inner wall of a shell. The shell is constructed by fixing a conical cylinder to the lower end of a cylindrical cylinder. One end of the sewage inlet 11 is connected to the upper side wall of the cylindrical cylinder and is positioned above the helical blades. A mixed liquid outlet is provided at the bottom end of the conical cylinder.

[0025] The device also includes an exhaust gas purification device 27, wherein the exhaust gas outlets of the high-efficiency flocculation mixing device 4, the screw sludge dewatering machine 5, the high-efficiency dissolved air flotation tank 7, the scum box 9 and the clear water tank 10 are respectively connected to the air inlet of the exhaust gas purification device 27 through pipelines.

[0026] A method for treating wastewater using a direct-injection wastewater treatment device with dry powder reagents is achieved through the following steps: (1) Determine the dosage of dry powder agent to be added based on the composition of the wastewater; (2) The wastewater is fed into the cyclone premixer 39 through the feed pipe a from the wastewater inlet 11, so that the wastewater forms a strong vortex turbulence in the cyclone premixer 39. At the same time, an appropriate amount of dry powder agent is added into the cyclone premixer 39 using the dosing skid box. The dry powder agent dissolves quickly after contacting the wastewater and flows out from the bottom of the cyclone premixer 39 with stirring. The frequency converter of each treatment chamber starts to work, so that the agent and the wastewater react fully to form a uniform flocculent liquid. (3) The outlet of the high-efficiency flocculation mixing device 4 is higher than the inlet of the screw sludge dewatering machine 5, and the flocculated liquid is sent into the screw sludge dewatering machine 5 by its own gravity for solid-liquid separation. (4) The mixed flocculant flows from the outlet 12 of the high-efficiency flocculation mixing device 4 into the inlet of the screw sludge dewatering machine 5 through the pipeline. Solid-liquid separation is completed in the dewatering machine. The sludge cake formed by dewatering is transported to the external sludge storage area through the sludge screw conveyor 13 from the sludge outlet of the screw sludge dewatering machine 5. Since the sludge screw conveyor is arranged on the second floor, it is convenient for various sludge receiving methods at the bottom, and it is convenient for vehicle-mounted sludge receiving and ton bag sludge receiving. The filtrate in the screw sludge dewatering machine 5 is sent into the high-efficiency dissolved air flotation tank 7 in the lower skid box by its own gravity through the pipeline b. This can effectively prevent the flocs from being destroyed before entering the flotation device. The scum in the water can be separated without secondary dosing, so that the filtrate and the dissolved air water in the high-efficiency dissolved air flotation tank 7 can be fully contacted, and the fine suspended matter can be lifted by the air bubbles to form a scum layer. (5) The scum on the upper layer of the high-efficiency dissolved air flotation tank 7 is collected into the scum collection tank by rotating scraper, and then flows into the scum box 9 by gravity. The clear water at the bottom layer flows out into the clear water tank 10 through the principle of communicating vessels. (6) Part of the water in the clear water tank 10 can be pumped back into the dissolved air tank 6 for recycling, and the other part of the clear water is discharged through the external drain pipe for subsequent processes or discharge in compliance with standards; (7) After the scum in the scum box 9 is homogenized by the agitator, it is transported back to the high-efficiency flocculation mixing device 4 by the scum pump 33 to realize the scum return and circulation treatment.

[0027] This invention discloses a method for wastewater treatment using a direct-injection dry powder wastewater treatment device. The design employs a combined process of "flocculation-dewatering-flotation": first, high-efficiency flocculation fully aggregates suspended particles into larger flocs; then, a sludge dewatering process separates high-solids-content sludge cake; and finally, the filtrate from dewatering enters the flotation unit for deep purification. This design effectively reduces the suspended solids load in the flotation water, alleviates the operating pressure on the flotation equipment, and improves the overall wastewater treatment capacity and the stability of the effluent quality, ensuring that the treatment effect meets standards.

[0028] This utility model discloses a direct-dosing wastewater treatment device using dry powder reagents. During operation, it uses an initial pilot-scale ratio as a baseline and online monitoring data as a correction basis. Automatic control is achieved through an explosion-proof PLC control cabinet. All monitoring data, control logic, and equipment status are processed through this cabinet. The control cabinet is equipped with a touchscreen that displays: inlet pH, inlet suspended solids concentration, outlet pH, outlet suspended solids concentration values ​​and trends, current screw conveyor frequency, dosing amount, and other operating parameters. It also provides alarms for abnormal conditions (such as sensor failure or exceeding limits) and supports manual / automatic mode switching for easy on-site debugging and emergency operation. The specific process is as follows: Before the system is put into operation, the dosing ratio of the target wastewater is first determined through small-scale experiments. Based on different water quality types (such as oily wastewater, electro-desalination wastewater, chemical wastewater, etc.), the optimal coagulation and flocculation effect and the corresponding sensor detection value range are determined by gradually adjusting the dosage of dry powder compound agent. The correspondence between water quality parameters (such as turbidity and pH value) and the dosage is established to provide a data foundation for subsequent automated control. During formal operation, a high-precision weight sensor is installed at the bottom of the hopper of the vacuum feeder 2 to detect the instantaneous conveying volume of the dry powder compound agent in real time and transmit the weight change signal to the PLC control cabinet. The PLC control cabinet calculates the actual dosage of the agent based on the weight change per unit time and compares it with the preset small-scale dosing model or water quality feedback model. Based on the comparison result, the frequency converter output frequency of the dry powder screw conveyor 3 is automatically adjusted to accurately control the screw feeding speed and realize dynamic closed-loop control of the dosage. When the front-end water quality monitoring sensors (such as turbidity, pH, etc.) detect fluctuations in the influent water quality or flow rate, the PLC control cabinet will automatically correct the current dosing rate according to the changes in water quality parameters, so that the dry powder dosage is matched with the sewage load, thereby realizing real-time dynamic adjustment of the sewage treatment process and improving the system's response sensitivity and effluent stability. In addition, the weight sensor also performs material level monitoring and replenishment control functions. When the weight sensor detects that the weight of the material in the hopper is lower than the set lower limit, the PLC controller will automatically start the vacuum feeder 2 to replenish the material, sucking the agent from the ton bag station into the hopper. When the weight in the hopper returns to the set upper limit, the PLC control cabinet immediately stops the feeder and returns to the normal dosing detection mode. During the feeding phase, due to the rapid feeding speed and unstable material flow, the system temporarily suspends real-time dosage calculations to avoid data errors. After feeding is completed, the system automatically re-collects the weight baseline value and resumes real-time monitoring and closed-loop control of the drug delivery rate, ensuring the entire process is continuous, stable, and accurate. Through the above-mentioned automated control logic, the addition of dry powder compound agents has achieved a fully automatic operation mode of "self-monitoring - self-adjustment - self-replenishment", which not only ensures the accuracy of dosing but also avoids human operation errors.

[0029] In operation, wastewater is first pumped from feed pipe a into cyclone premixer 39 via raw material pump 29, creating a strong vortex turbulence within the premixer. At this time, the online turbidity meter III 43 on feed pipe a monitors the impurity content of the wastewater in real time, and the pH transmitter I 31 monitors the pH value. The monitoring results are then fed back to the PLC control cabinet, which automatically calculates the required dosage based on a preset algorithm and adjusts the frequency converter of screw conveyor 3 to control the dosing rate of the dry powder compound agent, achieving real-time matching between the dosage and water quality fluctuations. The dry powder agent dissolves rapidly with the wastewater in the cyclone premixer 39, and flows out from the bottom of the premixer 39 into the high-efficiency flocculation mixing device 4 with stirring. The frequency converters in each treatment chamber begin operation, ensuring the agent and wastewater react fully to form a uniform flocculant. The stirring system operates in three stages: the first stage has a stirring speed of 80–120 km / h. The primary stirring speed is 100 rpm, preferably 100 rpm, for initial dispersion of the reagent; the secondary stirring speed is 60-80 rpm, preferably 70 rpm, to promote the formation and collision of micro-flocculations; the tertiary stirring speed is 40-60 rpm, preferably 50 rpm, to maintain the growth and stability of the flocs and form large flocs; the residence time of the liquid in the high-efficiency flocculation mixing device 4 is controlled at 10-20 minutes to ensure sufficient reaction and the formation of dense and stable flocs. The start and stop of the raw material pump 29 is automatically controlled by a single-flange level gauge installed in the housing 15, thereby maintaining a constant liquid level in the high-efficiency flocculation mixing device 4, ensuring stable reaction conditions and consistent treatment results.At this point, the flocculant then flows by gravity from outlet 12 into the screw conveyor sludge dewatering machine 5 for solid-liquid separation. During solid-liquid separation, the screw speed is generally 2-8. At rpm, the sludge moisture content is stabilized at 75%–60%. The sludge cake formed by dewatering by the screw conveyor 5 is transported to the external sludge storage area via the screw conveyor 13. The filtrate in the screw conveyor 5 is sent by gravity through pipeline b into the high-efficiency dissolved air flotation tank 7 in the lower skid-mounted box. This effectively prevents the flocs from being destroyed before entering the flotation device, and the scum in the water can be separated without secondary chemical addition. At this time, the online turbidity meter I32 on pipeline b will monitor the impurity content of the filtrate in real time and feed the monitoring results back to the PLC control cabinet. The filtrate entering the high-efficiency dissolved air flotation tank 7 is in full contact with the dissolved air water in the tank. The dissolved air pressure in the flotation tank is maintained at 0.35–0.45 MPa, the dissolved air water reflux ratio is controlled at 20%–30%, and the residence time of the treated liquid in the flotation tank is 10–15 minutes. In this stage, residual suspended solids, emulsified oil, and fine particles in the water are fully separated and floated to the surface (removal rate can reach over 90%), causing the fine suspended solids in the filtrate to be lifted by air bubbles to form a scum layer. The scum is collected into the scum collection tank by the rotating scraping mechanism in the high-efficiency dissolved air flotation tank 7, and then flows into the scum box 9 by gravity. The clear water at the bottom flows out into the clear water tank 10 through the principle of communicating vessels. Part of the water in the clear water tank 10 is pumped back into the dissolved air tank 6 by the dissolved air pump 34 for recycling, and the other part of the clear water is pumped out by the clear water export pump 35 and discharged from the discharge pipeline e. At this time, the pH transmitter II 36 and the online turbidity meter II 37 on the discharge pipeline e will monitor the pH value and impurity content of the discharged clear water in real time and feed back the monitoring results to the PLC control cabinet for use in subsequent processes or to achieve standard discharge.

[0030] During operation, when pH transmitter I31 detects fluctuations in the wastewater's pH value (such as a sudden increase / decrease in wastewater pH), it indicates a change in the wastewater's acidity or alkalinity, which may affect the reagent reaction efficiency. The PLC control cabinet will combine the monitoring results from pH transmitter II36 and pH transmitter I31 to calculate the required adjustment frequency, ensuring the outlet clean water's pH value returns to the target value. When the online turbidity meter III43 on feed pipeline a detects fluctuations in the wastewater's impurity content (such as a sudden increase / decrease in suspended solids), it indicates a change in the initial impurity content of the wastewater. The PLC control cabinet will... Based on the monitoring results of online turbidity meter Ⅲ43 and online turbidity meter Ⅱ37, determine whether the dosage needs to be adjusted (e.g., if the inlet suspended solids increase, the dosage may need to be increased in advance to cope with the increase in impurities); when online turbidity meter Ⅱ37 detects that the suspended solids concentration in the discharged clean water exceeds the standard, it indicates that the dosage of the reagent is insufficient, and the PLC control cabinet will directly increase the frequency of screw conveyor 3 to increase the dosage until the suspended solids concentration in the discharged clean water drops to the standard range; if the pH and suspended solids of the inlet wastewater are stable and the pH and suspended solids of the outlet clean water meet the standards, then maintain the current frequency operation.

[0031] The effects of this utility model will be illustrated below with examples from field experiments; Experiment location: Longfeng Oil Refinery, Daqing City Experimental protocol: such as Figure 4 As shown.

[0032] ① The desalination wastewater enters the high-efficiency flocculation mixing device 4 through the raw material pump 29, and dry powder agents are added online at the same time. After the desalination wastewater undergoes three-stage stirring and flocculation in the high-efficiency flocculation mixing device 4, the scum enters the screw sludge dewatering machine 5 through the screw pump. ② The scum is dewatered by the screw conveyor sludge dewatering machine 5, and the dewatered sludge cake is bagged. The resulting filtrate enters the high-efficiency dissolved air flotation tank 7 by gravity flow. ③ The scum generated after separation by the high-efficiency dissolved air flotation tank 7 is pumped into the high-efficiency flocculation mixing device 4, and the separated clear water is discharged after meeting the standards.

[0033] The dry powder reagent test calibration was conducted from 10:00 on May 12 to 10:00 on May 19, during which a total of 3,829 tons of wastewater were treated. , ,

[0034] Table 2 shows the various indicators of the water before and after treatment. As can be seen from the table, after the dry powder test, all the indicators of the effluent from the electro-desalination wastewater are within the specified range. The best COD removal rate is 97.48%, the oil removal rate is 89.46%, and the best suspended solids removal rate is over 99%.

[0035] The electrostatic desalination wastewater treatment unit used conventional flocculation process (PAC+PAM) from 7:00 on April 23 to 7:00 on April 30, during which time a total of 2,332 tons of wastewater were treated. ; .

[0036] in conclusion: To address the problems of low flocculation efficiency, poor reagent adaptability, difficulty in automation integration, and poor cake dewatering performance in conventional flocculation processes (PAC+PAM) during electrostatic precipitation wastewater treatment, this paper verifies the application effect of a novel dry powder reagent through systematic experiments. The results show that it is superior to conventional reagents in multiple dimensions, as summarized below: 1. Validation of flocculation effect and applicability Experiments show that the dry powder agent exhibits significant flocculation ability in electro-desalination wastewater. The resulting flocs are dense, settle rapidly, and produce effluent clarity significantly superior to the traditional PAC+PAM system. It demonstrates good adaptability to different wastewater types (such as raw water with significant differences in oil content, solids content, and COD), indicating its broad applicability in flocculation performance. 2. Processing stability and automation adaptability assessment Experimental results show that the dry powder reagent can maintain stable treatment capacity even under fluctuating raw water quality, with minimal fluctuations in effluent quality and strong resistance to shock loads. Furthermore, the reagent has good storage and transport properties, making it easy to integrate efficiently with automatic dosing systems, which is beneficial for the construction of skid-mounted, unattended intelligent water treatment systems. 3. Comparison of reagent consumption, water consumption, and operating costs Experimental results show that compared with the traditional PAC+PAM combination, dry powder reagents have a lower unit treatment cost in practical applications, and eliminate the need for multi-step dissolution and preparation processes, effectively reducing water consumption and operational steps. In terms of overall operating costs, dry powder reagents are more economical and are particularly suitable for continuous operation scenarios in large-scale electrostatic desalination plants. ; 4. Comparison of moisture content in mud cakes after floc dehydration Analysis of the moisture content of the sludge cake after floc dewatering revealed that the sludge cake treated with dry powder agents had a denser structure and a generally lower moisture content than the traditional PAC+PAM system, exhibiting better dewatering performance. This characteristic helps reduce the cost of subsequent sludge treatment and disposal, improving the overall system's economic efficiency and environmental friendliness.

[0037] In summary, dry powder reagents demonstrate significantly superior performance compared to traditional reagent combinations in electrostatic desalination wastewater treatment, not only in terms of flocculation effect, operational stability, and compatibility with automated systems, but also in their significantly improved treatment capacity. Furthermore, dry powder reagents offer multiple advantages, including low operating costs and excellent sludge treatment, showcasing promising prospects and engineering application value.

Claims

1. A direct-dosing wastewater treatment device using dry powder reagents, characterized in that... A device suitable for treating wastewater with dry powder reagents comprises two fixed skid-mounted boxes, a dosing skid-mounted box on one side of the lower skid-mounted box, and a PLC controller. A sludge dewatering unit is located in the upper skid-mounted box, and an air flotation unit is located in the lower skid-mounted box. A ton bag feeding station (1) is located in the dosing skid-mounted box. The sludge dewatering unit includes a high-efficiency flocculation mixing device (4), a screw conveyor sludge dewatering machine (5), a vacuum feeder (2), and a screw conveyor (3). The air flotation unit includes… Dissolved air tank (6), high-efficiency dissolved air flotation tank (7), air compressor (8), scum box (9), and clear water tank (10); the outlet of the ton bag feeding station (1) is connected to the inlet of the vacuum feeder (2) through a pipeline, the outlet of the vacuum feeder (2) is connected to the inlet of the screw conveyor (3), the outlet of the screw conveyor (3) is located at the dry powder inlet (24) above the feed end of the high-efficiency flocculation mixing device (4), and the sewage inlet (11) of the high-efficiency flocculation mixing device (4) is connected to the dry powder inlet (24) above the feed end of the high-efficiency flocculation mixing device (4). The feed pipe (a) is connected to the discharge port (12) and the feed port of the screw sludge dewatering machine (5) through a pipe. A sludge screw conveyor (13) is provided at the discharge port of the screw sludge dewatering machine (5). The filtrate outlet of the screw sludge dewatering machine (5) is connected to the liquid inlet of the high-efficiency dissolved air flotation tank (7) through a pipe (b). The air outlet of the air compressor (8) is connected to the air inlet of the dissolved air tank (6) through a pipe. The dissolved air water outlet of the dissolved air tank (6) is connected to the dissolved air water inlet of the high-efficiency dissolved air flotation tank (7) through a pipe. The pipelines are connected, and the slag outlet A of the high-efficiency dissolved air flotation tank (7) is connected to the feed inlet of the slag box (9) through a pipeline, and the liquid outlet B is connected to the liquid inlet of the clear water tank (10) through a pipeline. The sewage outlet of the slag box (9) is connected to the slag inlet (14) of the high-efficiency flocculation mixing device (4) through a pipeline c. Two water outlets are provided at the bottom of the clear water tank (10), one of which is connected to the water inlet of the dissolved air tank (6) through a pipeline d, and the other water outlet is connected to the external discharge pipeline e.

2. The wastewater treatment device for direct dosing of dry powder reagents according to claim 1, characterized in that... The high-efficiency flocculation mixing device (4) includes a rectangular box (15). Multiple support legs (16) are provided at the bottom of the box (15). Vertically upward partitions I (17) and vertically downward partitions II (18) are fixed at intervals on the bottom and top plates of the box (15), dividing the interior of the box (15) into multiple processing chambers. A variable frequency reducer is provided above each processing chamber. The output shaft of each variable frequency reducer passes through the box (15) and is placed inside it, with a rotating rod (22) fixed at its end. The lower end of each rotating rod (22) is rotatably connected to the bottom plate of the box (15). A stirring blade (23) is provided on the outer wall of each rotating rod (22). At the feed end of the box (15)... The box is provided with a dry powder inlet (24), and one or more exhaust gas outlets (25) are provided on the top plate of the box (15). A sewage inlet (11) and a scum inlet (14) are provided on the side wall of the feed end of the box (15), and a discharge outlet (12) is provided on the side wall of the discharge end. A cyclone premixer (39) is provided on the inner wall of the box (15) at the sewage inlet (11) and is connected to the sewage inlet (11). The upper inlet of the cyclone premixer (39) corresponds to the lower outlet of the dry powder inlet (24). The sewage pumped out by the raw material pump (29) forms a strong vortex in the cyclone premixer (39). The dry powder agent dissolves quickly after contacting the sewage and flows out from the bottom of the cyclone premixer (39) with stirring.

3. A direct-dosing wastewater treatment device for dry powder reagents according to claim 2, characterized in that... Partition I (17) and partition II (18) divide the box (15) into three processing chambers from the feed end to the discharge end. The speed of the first-stage variable frequency reducer (19) in the three processing chambers is 80-120 rpm, the speed of the second-stage variable frequency reducer (20) is 60-80 rpm, and the speed of the third-stage variable frequency reducer (21) is 40-60 rpm. Each of the three processing chambers is provided with a manhole (40) at the top, and each of the three manholes (40) is provided with a cover.

4. A direct-dosing wastewater treatment device for dry powder reagents according to claim 2, characterized in that... The upper end of the partition I (17) is separated from the top plate of the box (15), and the lower end of the partition II (18) is separated from the bottom plate of the box (15), so that the sewage flows in a serpentine manner in the box (15) and the combination time of the sewage and the dry powder agent is 10 to 20 minutes.

5. A direct-dosing wastewater treatment device for dry powder reagents according to claim 2, characterized in that... The cyclone premixer (39) is constructed by fixing a spiral blade inside a shell. The shell is constructed by fixing a conical cylinder to the lower end of a cylindrical cylinder. One end of the sewage inlet (11) is connected to the upper side wall of the cylindrical cylinder and is positioned above the spiral blade. A mixed liquid outlet is provided at the bottom end of the conical cylinder.

6. A direct-dosing wastewater treatment device for dry powder reagents according to claim 1, characterized in that... It also includes an exhaust gas purification device (27), wherein the exhaust gas outlets of the high-efficiency flocculation mixing device (4), the screw sludge dewatering machine (5), the high-efficiency dissolved air flotation tank (7), the scum box (9) and the clear water tank (10) are respectively connected to the air inlet of the exhaust gas purification device (27) through pipelines.

7. A direct-injection wastewater treatment device for dry powder reagents according to claim 1, characterized in that an electric two-way valve (28), a raw material pump (29), an electromagnetic flowmeter I (30), a pH transmitter I (31), and an online turbidity meter III (43) are provided on the feed pipeline a; an online turbidity meter I (32) is provided on the pipeline b; a scum pump (33) is provided on the pipeline c; a dissolved air pump (34) is provided on the pipeline d; and a clean water export pump (35), a pH transmitter II (36), an online turbidity meter II (37), and an electromagnetic flowmeter II (38) are provided on the discharge pipeline e.

8. A direct-dosing wastewater treatment device for dry powder reagents according to claim 6, characterized in that... The PLC controller is electrically connected to the electric two-way valve (28), the raw material pump (29), the electromagnetic flowmeter I (30), the pH transmitter I (31), the online turbidity meter III (43), the online turbidity meter I (32), the scum pump (33), the dissolved air pump (34), the clean water export pump (35), the pH transmitter II (36), the online turbidity meter II (37), and the electromagnetic flowmeter II (38).

Images