Intelligent crystallization and granulation treatment method and system for sewage and wastewater

Abstract

The application discloses a kind of intelligentization sewage crystallization granulation processing method and system, the system includes the pretreatment unit, crystallization granulation device and granule discharge recovery device sequentially connected along the direction of water inlet;Pretreatment unit is equipped with pretreatment pool, and inlet and outlet are equipped on pretreatment pool, and water quality intelligent analysis device is installed at inlet, and outlet is connected with crystallization granulation device by pipeline, anode electrode stick and cathode electrode stick are installed in pretreatment pool, and power supply for anode electrode stick and cathode electrode stick is equipped outside pretreatment pool, and power supply is connected with anode electrode stick and cathode electrode stick by circuit.The method disclosed by the application carries out water quality monitoring at water inlet and outlet, and the process of back end is matched according to water quality, and the method is intelligently operated, and easy to operate;By setting crystallization granulation device, product recovery is convenient, by setting granule discharge recovery device, it has the functions of draining, air drying and subpackaging, and product collection is convenient.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of water treatment, and particularly relates to an intelligent crystallization and granulation treatment method and system for sewage. BACKGROUND

[0002] Excessive hardness in water can have a serious impact on people's production and life. WHO believes that when the total hardness in water is higher than 100 mg / L, the buffering capacity of the water is at a low level, at which time the water is more corrosive to the water pipeline, and when the total hardness in water is higher than 200 mg / L, scaling problems will occur in water storage devices and water distribution pipe networks. When the hardness in human drinking water is too high, it will have an adverse effect on the body. Short-term drinking of high-hardness water can cause symptoms such as intestinal function disorder and diarrhea. And long-term drinking of high-hardness water can cause excessive calcium content in the human body, which has a negative impact on body growth and development.

[0003] In industrial production, high-hardness water can cause many problems such as scaling in the production system. The water consumption of cooling industrial production equipment accounts for 80% of the total water consumption in industrial production. These cooling systems are mostly open-loop circulating cooling systems, that is, the circulating cooling water is in long-term contact with air. In the process of cooling, various inorganic ions and organic substances in the water are continuously enriched and concentrated to form a water body with high salt content. The ions in the water, such as Ca 2+ , Mg 2+ , Fe 2+ , Mn 2+ , As 3 + and F - , especially Ca 2+ and Mg 2+ , will also increase a lot. Scaling on the surface of the production system will have a serious impact on the heat transfer performance and uniformity of the system, and in severe cases, it may cause production accidents. In order to ensure the normal operation of the production system, it is necessary to continuously replace and supplement fresh circulating water during operation, and to discharge part of the wastewater with high salt content, so as to reduce or remove the hardness ions in the water and avoid scaling.

[0004] With the continuous improvement of energy saving and emission reduction requirements, in order to increase the number of times of circulating cooling water and reduce the amount of water supplement and wastewater discharge, it is necessary to soften the circulating cooling water and improve the reuse rate of sewage. Therefore, reducing the hardness of sewage in the industrial production process is of great significance for saving water resources.

[0005] In the existing crystallization granulation treatment methods, such as a method for treating circulating sewage of a power plant by using an electrochemical crystallization granulation device (CN11675354A), a chemical crystallization granulation circulating fluidized bed treatment device (CN105502692B), and a full-automatic chemical crystallization circulating granulation fluidized bed water treatment system (CN108467135A), there are many problems such as complex and difficult-to-control process, automatic but not intelligent, lack of online monitoring, difficulty in coping with complex and variable water quality, difficulty in cleaning the crystallization granulation device, and inconvenience in collecting the granular products. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a reasonable and intelligent wastewater crystallization granulation treatment method and system to overcome the shortcomings of the prior art. The method and system can not only consider the influence of variable water quality but also intelligently analyze the influent and effluent. The crystallization granulation device can be automatically cleaned, and the generated particles can be automatically recycled. The method and system can ensure that the water quality meets the standards, and the solid waste is recycled, while being convenient and safe.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] An intelligent wastewater crystallization granulation treatment method and system, characterized in that the method comprises the following steps: first, monitoring the water quality of wastewater; if the water quality is poor, the wastewater is pretreated; if the water quality is normal, the wastewater is subjected to crystallization granulation by adding seed crystals, sodium hydroxide, and sodium carbonate to make the calcium ions and magnesium ions in the water fully react with the reagents. In the flowing process, calcium carbonate continuously grows on the surface of the seed crystals to realize chemical cyclic crystallization granulation. Finally, mature particles are obtained. The mature particles and water are subjected to solid-liquid separation, and PAC and PAM are added according to the water quality. After the flocculation in the water, the water is discharged. The treated water is subjected to effluent water quality monitoring and is successfully discharged. If the water quality does not meet the standards, the wastewater is pretreated again.

[0009] The technical problem to be solved by the present application can also be realized by the following technical solutions: the water quality monitoring content includes COD and hardness, and the hardness includes calcium-containing hardness and magnesium-containing hardness.

[0010] The technical problem to be solved by the present application can also be realized by the following technical solutions: the seed crystals are selected from one or more of quartz sand, garnet, calcium carbonate, aragonite, and calcite.

[0011] A system for realizing the above-mentioned intelligent wastewater crystallization granulation treatment method, characterized in that the system comprises a pretreatment unit, a crystallization granulation device, and a particle discharge and recovery device connected in sequence along the direction of the influent.

[0012] The pre-treatment unit is provided with a pre-treatment tank, a water inlet and a water outlet are arranged on the pre-treatment tank, a water quality intelligent analysis device is installed at the water inlet, the water outlet is connected with the crystallization and granulation device through a pipeline, an anode electrode rod and a cathode electrode rod are installed in the pre-treatment tank, a power supply for supplying power to the anode electrode rod and the cathode electrode rod is arranged outside the pre-treatment tank, the power supply is connected with the anode electrode rod and the cathode electrode rod through a circuit, and a switch is installed on the circuit.

[0013] The crystallization and granulation device comprises a support and a crystallization and granulation tank, the crystallization and granulation tank is installed on the support through a vibration assembly, a water inlet is arranged at the top of the crystallization and granulation tank, a drain pipe and a particle pipeline are arranged at the bottom of the crystallization and granulation tank, a gas distribution assembly is installed in the crystallization and granulation tank, and a vibrator is installed on the side wall of the crystallization and granulation tank.

[0014] The particle discharge and recovery device comprises a particle recovery box and a liquid storage bin arranged below the particle recovery box, the particle recovery box and the liquid storage bin are both open at the top and bottom, a draining net is installed between the particle recovery box and the liquid storage bin, a particle inlet connected with the particle pipeline of the crystallization and granulation tank is arranged above the particle recovery box, a particle outlet is arranged on the particle recovery box close to the draining net, an inclined flow guide groove is installed at the particle outlet, a receiving hopper is connected with the discharge end of the flow guide groove, a water outlet is arranged on the liquid storage bin, a water quality intelligent analysis device is installed at the water outlet, an air outlet is arranged at the top of the particle recovery box, and a blower is installed at the air outlet.

[0015] The technical problem solved by the application can also be solved by the following technical scheme, the drain pipe of the crystallization and granulation tank is connected with a solid-liquid separation device, the solid-liquid separation device comprises a solid-liquid separation cylinder, a water inlet pipeline and a water outlet pipeline connected with the crystallization and granulation tank are arranged on the solid-liquid separation cylinder, the water outlet pipeline is connected with a reflux pipeline connected with the pre-treatment tank through a three-way joint, a secondary medicament adding device is installed on the solid-liquid separation cylinder, and a stirrer is installed in the solid-liquid separation cylinder.

[0016] The technical problem solved by the application can also be solved by the following technical scheme, a tower grate for accelerating drying particles is installed at the center of the draining net.

[0017] The technical problem solved by the application can also be solved by the following technical scheme, the primary medicament adding device and the secondary medicament adding device both comprise a medicament storage tank and a medicament adding pipeline, the medicament storage tank is communicated with the solid-liquid separation cylinder through the medicament adding pipeline, and a medicament adding pump is installed on the medicament adding pipeline.

[0018] The technical problem to be solved by the present application can also be realized by the following technical scheme, the seed adding device comprises a seed storage tank and a seed adding pump, and the seed storage tank and the seed adding pump are connected through a seed conveying pipe.

[0019] The technical problem to be solved by the present application can also be realized by the following technical scheme, the air distribution assembly comprises a gas conveying main pipe and a plurality of air distribution branch pipes, the air distribution branch pipes are uniformly distributed at the bottom of the crystallization granulation tank, the air distribution branch pipes are communicated with the air blower through the gas conveying main pipe, and a plurality of air outlets are arranged on the pipe wall of the air distribution branch pipes.

[0020] The technical problem to be solved by the present application can also be realized by the following technical scheme, the drain pipe of the crystallization granulation tank is connected with the upper water inlet of the pretreatment pool through a tee joint, and a one-way valve is installed on the pipeline connected with the upper water inlet of the pretreatment pool, so that the water can be conveniently treated again.

[0021] Compared with the prior art, the present application has the following technical effects:

[0022] Firstly, the method of the present application monitors the water quality at the water inlet and outlet, and can match the process of the rear end according to the water quality, so as to realize intelligent operation and simple operation, and especially some work prone to safety hazards such as cleaning of the device cylinder into a limited space can be realized intelligently.

[0023] Secondly, by arranging the vibration assembly on the crystallization granulation tank, the crystallization granulation device has the functions of vibration, addition of scale remover and the like, so as to facilitate the improvement of product recovery efficiency.

[0024] Thirdly, by arranging the draining net, the tower grate and the air blower, the particle discharge and recovery device has the functions of draining, air blowing and drying and sub-packaging, so as to accelerate the drying speed of the particles. BRIEF DESCRIPTION OF DRAWINGS

[0025] Fig. 1 The structural principle diagram of the intelligent sewage crystallization granulation treatment system of the present application is shown in the figure.

[0026] Fig. 2 The structural diagram of the crystallization granulation device is shown in the figure.

[0027] Fig. 3 The structural diagram of the particle discharge and recovery device is shown in the figure.

[0028] In the figure: 1 - intelligent water quality analysis device, 2 - pretreatment unit, 3 - crystallization granulation device, 4 - seed adding device, 5 - solid-liquid separation device, 6 - intelligent water quality analysis device, 7 - particle discharge recovery device, 8 - support, 9 - crystallization granulation tank, 10 - vibration seat, 11 - fixed seat, 12 - positioning rod, 13 - spring, 14 - particle recovery box, 15 - particle inlet, 16 - air blower, 17 - tower grate, 18 - flow guide groove, 19 - receiving hopper, 20 - liquid storage bin, 21 - draining net. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments.

[0030] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0031] Reference Figs. 1-3 An intelligent sewage crystallization granulation treatment method, which comprises the following steps: first, monitoring the water quality of sewage, wherein the water quality monitoring content includes COD and hardness, the hardness includes calcium-containing hardness and magnesium-containing hardness; if the water quality is poor and does not pass the detection, pretreatment is performed; if the water quality is normal and passes the detection, crystallization granulation is performed; by adding seeds, sodium hydroxide and sodium carbonate, the calcium ions and magnesium ions in the water fully react with the reagents, and the calcium carbonate continuously grows on the surface of the seeds in the flow process, realizing chemical circulation crystallization granulation, and finally obtaining mature particles; the mature particles and water are subjected to solid-liquid separation, and PAC and PAM are added according to the water quality; the water is discharged after the flocculation of the water; the treated water is successfully discharged after water quality monitoring; and if the water quality does not meet the standard, the above pretreatment is switched to re-treatment.

[0032] The seeds are selected from one or more of quartz sand, garnet, calcium carbonate, aragonite or calcite.

[0033] A system for realizing the above-mentioned intelligent sewage crystallization granulation treatment method, which comprises a pretreatment unit 2, a crystallization granulation device 3 and a particle discharge recovery device 7 connected in sequence along the water inlet direction.

[0034] The pre-treatment unit 2 is provided with a pre-treatment tank, which is provided with a water inlet and a water outlet, the water inlet is provided with an intelligent water quality analysis device 1, the water outlet is connected with the crystallization granulation device 3 through a pipeline, the pre-treatment tank is provided with an anode electrode rod and a cathode electrode rod, and the pre-treatment tank is provided with a power supply for supplying power to the anode electrode rod and the cathode electrode rod, the power supply is connected with the anode electrode rod and the cathode electrode rod through a circuit, and a switch is installed on the circuit.

[0035] The crystallization granulation device 3 comprises a support 8 and a crystallization granulation tank 9, the crystallization granulation tank 9 is installed on the support through a vibration assembly, the top of the crystallization granulation tank 9 is provided with a water inlet, the bottom of the crystallization granulation tank 9 is provided with a drain pipe and a particle pipeline, the crystallization granulation tank 9 is provided with a gas distribution assembly, and the sidewall of the crystallization granulation tank 9 is provided with a vibrator; the vibration assembly comprises a fixed seat 11 installed on the support and a vibration seat 10 installed on the outer wall of the crystallization granulation tank 9, the vibration seat 10 is provided with a positioning rod 12 penetrating downward through the fixed seat 11, and a vibration spring is sleeved on the positioning rod 11 between the vibration seat 11 and the fixed seat 10; the crystallization granulation tank 9 is further connected with a first medicament adding device and a seed adding device 4.

[0036] The particle discharge and recovery device comprises a particle recovery box 14 and a liquid storage bin 20 arranged below the particle recovery box 14, the particle recovery box 14 and the liquid storage bin 20 are provided with a dewatering net 21, the particle recovery box 14 above the dewatering net 21 is provided with a particle inlet 15 connected with the particle pipeline of the crystallization granulation tank 9, the particle recovery box 14 close to the dewatering net 21 is provided with a particle outlet, the particle outlet is provided with an inclined flow guide groove 18, the outlet end of the flow guide groove 18 is connected with a receiving hopper 19, the liquid storage bin 20 is connected with a drain outlet, the drain outlet is provided with an intelligent water quality analysis device 6, the top of the particle recovery box 14 is provided with an air outlet, the air outlet is provided with a blower 16, a tower grate 17 for accelerating drying particles is arranged in the center of the dewatering net 21, and corresponding power devices such as water pumps and material pumps can be arranged on the above-mentioned pipelines or channels according to the use requirements, so that water or particles can smoothly enter the next process.

[0037] The drain pipe of the crystallization granulation tank 9 is connected with a solid-liquid separation device, the solid-liquid separation device 5 comprises a solid-liquid separation cylinder, the solid-liquid separation cylinder is provided with a water inlet pipeline and a water outlet pipeline connected with the crystallization granulation tank, the water outlet pipeline is connected with a backflow pipeline connected with the pre-treatment tank through a three-way joint, the solid-liquid separation cylinder is provided with a second medicament adding device, and the solid-liquid separation cylinder is provided with a stirrer.

[0038] The first medicament adding device and the second medicament adding device both comprise a medicament storage tank and a medicament adding pipeline, the medicament storage tank is communicated with the solid-liquid separation cylinder through the medicament adding pipeline, and the medicament adding pipeline is provided with an adding pump.

[0039] The seed crystal feeding device 4 includes a seed crystal storage tank and a seed crystal feeding pump, and the seed crystal storage tank and the seed crystal feeding pump are connected by a seed crystal delivery pipe.

[0040] The gas distribution assembly includes a main gas supply pipe and several branch gas distribution pipes. The branch gas distribution pipes are evenly distributed at the bottom of the crystallization granulation tank. The branch gas distribution pipes are connected to the blower through the main gas supply pipe. Several gas outlet holes are provided on the pipe wall of the branch gas distribution pipes.

[0041] The drain pipe of the crystallization granulation tank is connected to the water inlet of the pretreatment tank via a tee. A one-way valve is installed on the pipe connected to the water inlet of the pretreatment tank to facilitate the retreatment of unqualified water.

[0042] The specific working process of the method and system described in this invention is as follows:

[0043] Wastewater enters the system described in this application. An intelligent water quality analysis device is installed at the inlet. Based on the system's monitoring data, if the water quality is poor and will affect subsequent treatment, the wastewater enters the pretreatment unit. If the water quality is normal, it enters the crystallization and granulation device. Seed crystals are added to the crystallization and granulation device through a seed crystal addition device. At the same time, sodium hydroxide and sodium carbonate are added to the crystallization and granulation device through a dosing system. In this system, calcium and magnesium ions in the water react fully with the reagents. During the flow process, calcium carbonate continuously grows on the surface of the seed crystals, realizing chemical cycle crystallization and granulation. Finally, the mature granules are discharged from the granule discharge and recovery device. The water then enters the solid-liquid separation device, and PAC and PAM are added according to the water quality. After the flocs in the water settle, they are discharged from the bottom of the device. The treated water is discharged smoothly from the system after passing through the effluent water quality monitoring device. If the water quality does not meet the standards, it can be switched to the inlet system for further treatment.

[0044] (1) Intelligent water quality analysis device: Wastewater is monitored online at the inlet of the device. The monitoring content includes COD and hardness (including calcium hardness and magnesium hardness). The monitoring results are automatically fed back to the back-end unit.

[0045] (2) Pretreatment unit (optional): According to the data monitoring results of the water quality analysis system, when the COD is high, the water quality intelligent analysis system determines that if the increase in COD can affect the downstream crystallization and granulation, it is necessary to switch to the electrode pretreatment unit. COD can be decomposed by electrode discharge to reduce the impact of COD on subsequent crystallization and granulation.

[0046] (3) The crystallization granulation device: the wastewater enters the crystallization granulation device from the lower end with high upward flow rate through the water distribution assembly, and the ions in the water continuously grow on the surface of the crystal seeds during the flow process to realize chemical circulation crystallization granulation; since the device is easy to scale in the crystallization granulation process, it needs to be cleaned manually regularly, but frequent manual cleaning not only has high cost, but also increases the safety risk of frequent access to the manhole. The crystallization granulation device has the functions of oscillation, rotation, addition of descaling agent, etc., and can be basically cleaned through the above structure, so that the frequency of manual cleaning is reduced;

[0047] (4) The crystal seed adding device: the crystal seed material is quartz sand or garnet or calcium carbonate or aragonite or calcite;

[0048] (5) The solid-liquid separation device: the precipitates or suspended matters such as magnesium hydroxide formed in the water are separated from the water to optimize the turbidity and SS of the water;

[0049] (6) The effluent water quality monitoring device: the effluent water passes through the effluent online monitoring system, and once it is found that the key water quality index exceeds the limit value, the water inlet unit can be switched to further treatment;

[0050] (7) The particle discharge and recovery device: a draining, air drying and sub-packaging system is arranged at the product outlet of the crystallization granulation device, and whether the system or part of the functions in the system is used can be selected according to the drying requirement of the product.

[0051] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. An intelligent method for treating wastewater through crystallization and granulation, characterized in that, The method involves first monitoring the water quality of the wastewater. If the water quality is poor and fails the test, pretreatment is performed. If the water quality is normal and passes the test, crystallization granulation is carried out. By adding seed crystals, sodium hydroxide, and sodium carbonate, the calcium and magnesium ions in the water react fully with the reagents. During the flow process, calcium carbonate continuously grows on the surface of the seed crystals, achieving chemical cycle crystallization granulation, and finally obtaining mature granules. The mature granules and water are then separated into solid and liquid components. PAC and PAM are added according to the water quality. The flocs in the water are discharged after sedimentation. The treated water is discharged smoothly after effluent water quality monitoring. If the water quality does not meet the standards, the process is switched back to the above pretreatment and re-treated. The method employs a system comprising a pretreatment unit, a crystallization granulation device, and a particle discharge recovery device connected sequentially along the water inlet direction. The pretreatment unit is equipped with a pretreatment tank, which has an inlet and an outlet. An intelligent water quality analysis device is installed at the inlet, and the outlet is connected to the crystallization and granulation device through a pipe. An anode electrode rod and a cathode electrode rod are installed inside the pretreatment tank. A power supply for the anode electrode rod and cathode electrode rod is provided outside the pretreatment tank. The power supply is connected to the anode electrode rod and cathode electrode rod through a circuit, and a switch is installed on the circuit. The crystallization granulation device includes a support frame and a crystallization granulation tank. The crystallization granulation tank is mounted on the support frame via a vibration assembly. The top of the crystallization granulation tank has an inlet connected to the outlet of the pretreatment tank. The bottom of the crystallization granulation tank has a drain pipe and a particle pipeline. An air distribution assembly is installed inside the crystallization granulation tank, and a vibrator is installed on the side wall of the crystallization granulation tank. The particle discharge and recovery device includes a particle recovery box with openings at both the top and bottom, and a storage tank located below the particle recovery box. A drain screen is installed between the particle recovery box and the storage tank. The particle recovery box above the drain screen has a particle inlet connected to the particle pipeline on the crystallization granulation tank. The particle recovery box near the drain screen has a particle outlet. An inclined guide channel is installed at the particle outlet, and a receiving hopper is connected to the discharge end of the guide channel. A drain outlet is connected to the storage tank for drainage. The outlet is equipped with an intelligent water quality analysis device, and the top of the particle recovery box is equipped with an exhaust vent, at which a blower is installed.

2. The intelligent wastewater crystallization and granulation treatment method according to claim 1, characterized in that, The water quality monitoring includes COD and hardness, with hardness including calcium-containing hardness and magnesium-containing hardness.

3. The intelligent wastewater crystallization and granulation treatment method according to claim 1, characterized in that, The seed crystals are selected from one or more of the following: quartz sand, garnet, calcium carbonate, aragonite, or calcite.

4. The intelligent wastewater crystallization and granulation treatment method according to claim 1, characterized in that, The vibration assembly includes a fixed seat mounted on a bracket and a vibration seat mounted on the outer wall of the crystallization granulation tank. The vibration seat is provided with a positioning rod that passes downward through the fixed seat. A vibration spring is sleeved on the positioning rod between the vibration seat and the fixed seat. The crystallization granulation tank is also connected to a primary reagent dosing device and a seed crystal dosing device.

5. The intelligent wastewater crystallization and granulation treatment method according to claim 4, characterized in that, The drain pipe of the crystallization granulation tank is connected to a solid-liquid separation device. The solid-liquid separation device includes a solid-liquid separation cylinder. The solid-liquid separation cylinder is equipped with an inlet pipe and an outlet pipe connected to the crystallization granulation tank. The outlet pipe is connected to a return pipe connected to the pretreatment tank via a tee. A secondary reagent dosing device is installed on the solid-liquid separation cylinder. A stirrer is installed inside the solid-liquid separation cylinder.

6. The intelligent wastewater crystallization and granulation treatment method according to claim 5, characterized in that, Both the primary and secondary reagent dosing devices include a reagent storage tank and a reagent dosing pipeline. The reagent storage tank is connected to the solid-liquid separation cylinder through the reagent dosing pipeline, and a dosing pump is installed on the reagent dosing pipeline. The seed crystal addition device includes a seed crystal storage tank and a seed crystal addition pump, and the seed crystal storage tank and the seed crystal addition pump are connected by a seed crystal delivery pipe.

7. The intelligent wastewater crystallization and granulation treatment method according to claim 1, characterized in that, A grate for accelerating the drying of particles is installed at the center of the drain net.

8. The intelligent wastewater crystallization and granulation treatment method according to claim 1, characterized in that, The gas distribution assembly includes a main gas supply pipe and several branch gas distribution pipes. The branch gas distribution pipes are evenly distributed at the bottom of the crystallization granulation tank. The branch gas distribution pipes are connected to the blower through the main gas supply pipe. Several gas outlet holes are provided on the pipe wall of the branch gas distribution pipes.

9. The intelligent wastewater crystallization and granulation treatment method according to claim 1, characterized in that, The drain pipe of the crystallization granulation tank is connected to the water inlet of the pretreatment tank via a tee, and a one-way valve is installed on the pipe connected to the water inlet of the pretreatment tank via the tee.

Images