An epoxy chloropropane wastewater treatment device and treatment method

Abstract

The present invention discloses an epoxy chloropropane wastewater treatment device and a treatment method, belonging to the technical field of water treatment. The epoxy chloropropane wastewater treatment device includes a preparation tank and a biological tank, and further includes: an alkali solution addition combined tank connected in series between the preparation tank and the biological tank. The alkali solution addition combined tank includes a plurality of monomer tanks and corresponding storage tanks. The plurality of monomer tanks are connected in series through overflow ports, and a solid collector is connected through the bottom of the monomer tank. Through the setting of the alkali solution addition combined tank and the reaction tank, when adding the alkali solution, the series-connected monomer tanks can add the alkali solution in batches to gradually adjust the wastewater to the required pH value. In the alkali hydrolysis stage, a circulating water path is formed between the downstream monomer tank and the reaction tank, and the wastewater can timely supplement the alkali solution during the circulating flow to ensure the stability of the pH value. In addition, through the vertical arrangement of the circulating flow and the heater, the stability of the temperature and the rationality of the pH value can improve the alkali hydrolysis efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment, and particularly relates to an epoxy chloropropane wastewater treatment device and a treatment method. Background Art

[0002] During the production process of pharmaceutical enterprises, a kind of wastewater containing epoxy chloropropane will be discharged. When the concentration in the wastewater is greater than 55 mg / L, it will have an inhibitory effect on biochemical bacteria. If the concentration is not controlled, it will affect the stable operation of the biochemical system. Therefore, this kind of wastewater needs to be subjected to corresponding pretreatment to destroy its molecular structure before entering the biochemical system.

[0003] However, during pretreatment, conventional adsorption methods, membrane separation methods, and ion exchange methods have high treatment costs because of the high cost of consumables and the need for regular replacement and maintenance. The distillation method and advanced oxidation method require high-energy-consuming equipment such as long-term high-temperature heating or ozone generators, resulting in high pretreatment energy consumption. However, if epoxy chloropropane is not separated, the wastewater contains a large amount of chlorinated organic compounds, with poor biodegradability and great harm to the environment after discharge. In view of this, an epoxy chloropropane wastewater treatment device and a treatment method are provided. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the above-mentioned disadvantages of the prior art and provide an epoxy chloropropane wastewater treatment device and a treatment method.

[0005] The technical solution adopted to solve the above technical problem is as follows:

[0006] An epoxy chloropropane wastewater treatment device includes a preparation tank and a biological tank, and further includes: an alkali solution addition combined tank connected in series between the preparation tank and the biological tank. The alkali solution addition combined tank includes a plurality of monomer tanks and corresponding storage tanks. The plurality of monomer tanks are connected in series through overflow ports, and a solid collector is connected through the bottom of the monomer tank.

[0007] A reaction tank connected in series between the alkali solution addition combined tank and the biological tank. A circulating water path is formed between the downstream monomer tank and the reaction tank through a reflux pipe and a water inlet pipe, and the reaction tank is communicated with the biological tank through a water outlet pipe.

[0008] A heater located in the reaction tank. The heater includes a vertically arranged electric heating plate, and a corrugated plate one and a corrugated plate two that can slide horizontally along the extending direction of the electric heating plate. The corrugated plate one and the corrugated plate two are connected through a limiting member. The vertical side wall of the electric heating plate has a wavy side surface, and a contact surface one and a contact surface two are provided at the positions corresponding to the wavy side surface of the corrugated plate one and the corrugated plate two.

[0009] Design of the lye addition combined pool. When adding lye, multiple monomer pools are connected in series to add lye in batches. With a pH sensor, the wastewater can be gradually adjusted to the required pH value, preventing uneven mixing caused by adding a large amount of lye in a short time. The continuous addition in small amounts and multiple times ensures high-precision adjustment. During the alkali hydrolysis reaction process, the wastewater circulates between the downstream monomer pool and the reaction pool, timely replenishing the consumed lye to ensure the stability of the pH value. Additionally, through the vertical arrangement of the circulation flow and the heater, the wastewater can be fully mixed and evenly heated, reducing the time required for alkali hydrolysis. The corrugated plate 1 and the corrugated plate 2 slide reciprocally left and right along the heater. The corrugated plate 1 and the corrugated plate 2 are made of good heat conductors, which can increase the effective contact area between the heater and the wastewater through the corrugated plate 1 and the corrugated plate 2, and use the sliding of the corrugated plate 1 and the corrugated plate 2 to clean the solid impurities on the surface of the heater, ensuring the heating efficiency. At the same time, in the corrugated structure, when the wave crests are superposed and the wave troughs are superposed, intermittent water passing gaps will appear and disappear between the corrugated plate 1 and the corrugated plate 2 and the heater. Combined with the flow of the wastewater, intermittent jets are generated at the heater, assisting in solid cleaning and increasing the flow mixing efficiency between the upper and lower layers of the wastewater, further improving the alkali hydrolysis efficiency. Epichlorohydrin in the wastewater after alkali hydrolysis is decomposed, preventing it from entering the biological pool with the wastewater and affecting the survival of microorganisms and the decomposition of organic matter.

[0010] Furthermore, the preparation pool is connected to the upstream monomer pool through a liquid supply pipe, the storage tank is connected to the monomer pool through an addition pipe, a cavity is formed by enclosing the guide member 1, the monomer pool, and the guide member 2. The water outlet of the return pipe, the water outlet of the liquid supply pipe, and the water outlet of the addition pipe are arranged close to the top surface of the guide member 1. A stirrer is installed inside the monomer pool.

[0011] Through the above technical solution, to improve the mixing efficiency, the guide member 1 adopts an elastic membrane structure to eliminate the dead corner area under the liquid supply pipe and the addition pipe. The incoming high-concentration wastewater and lye quickly enter the middle of the monomer pool under the guidance of the guide member 1. When the stirrer works, the guide member 1 will collapse due to the impact of the wastewater due to the existence of the cavity, and when it rebounds, it will push the liquid above the guide member 1 close to the stirrer, enabling the continuously incoming high-concentration wastewater and lye to be quickly added to the stirring and mixing.

[0012] Furthermore, the monomer pool adopts a rectangular structure. A guide member 1 is installed at the corner of the monomer pool opposite to the solid collector. A guide member 2 is installed between the guide member 1 and the inner wall of the bottom end of the monomer pool. The guide member 2 has an inclined top surface, and the lowest point of the inclined top surface of the guide member 2 is located at the solid collector.

[0013] Through the above technical solution, the inclined design of the first guide member and the second guide member will guide the generated solid impurities to the position of the solid collector. The inner corner of the monomer pool at the position of the solid collector is not provided with the first guide member, and a slow-flow range can be reserved at the solid collector so that the solid impurities can settle more effectively and be collected by the solid collector, and quickly discharged from the monomer pool to avoid continuous accumulation.

[0014] Further, the solid collector includes a housing. The housing is provided with a communication port at the vertical side wall inside the monomer pool. A plurality of vertical plates are installed in the communication port of the housing. A screw blade is installed between the housing and the vertical plates. The inner wall of the housing corresponding to the screw blade is provided with a semi-circular arc groove, and the vertical plate corresponding to the screw blade is provided with a semi-circular arc surface. The housing is provided with a mesh plate directly above the screw blade.

[0015] Through the above technical solution, a specific solid collector is disclosed. The communication port is directly opposite to the lowest position of the second guide member, so that solid impurities can enter the housing more conveniently. When the screw blade does not rotate, the wastewater entering the housing will flow out of the housing upward through the mesh plate. The screw blade acts as a baffle, and the solid impurities settle in the semi-circular arc groove under the friction and blockage of the vertical plate and the screw blade. When the screw blade rotates, the spiral structure of the screw blade can be used to discharge the collected solid impurities from the outlet at the right end. The vertical plate plays a limiting role to prevent the screw blade from disengaging from the semi-circular arc groove and ensure the stable rotation of the screw blade.

[0016] Further, a storage tank is provided between the reflux pipe and the middle monomer pool. A three-way valve is installed at the conduction position of the reflux pipe and the water outlet pipe. The water outlet pipe is connected to a neutralization tank through the three-way valve. The neutralization tank is located upstream of the biological tank.

[0017] Through the above technical solution, to ensure the pH value control during the alkali hydrolysis process, at this time, other monomer pools stop working, and the preparation pool also stops inputting new wastewater. The most downstream monomer pool and the reaction pool form an integral body, and the reflux pipe and the water outlet pipe form a water flow circuit between them, so that the wastewater in the reaction pool flows back into the monomer pool, entraining the alkali solution into the reaction pool for rapid alkali solution supplementation. It can also make the wastewater in the reaction pool be disturbed and mixed by circulating flow, shortening the time required for alkali hydrolysis, and can also flow through the heater position alternately for heating to ensure the stable heat of the wastewater.

[0018] Further, the reaction pool includes a bottom shell. An inclined enclosure is provided at the opening position at the top of the bottom shell. A vertical enclosure is provided at the opening position at the top of the inclined enclosure. The bottom shell, the inclined enclosure and the vertical enclosure enclose a cavity with an upward opening. A slag discharge pipe is installed at the bottom of the bottom shell. The outlet of the solid collector and the outlet of the slag discharge pipe are connected to a collection tank through a pipeline. The collection tank is connected to a solid-liquid separator through a pipeline.

[0019] Through the above technical solution, a specific configuration of a reaction tank is disclosed. The bottom shell is wider at the top and narrower at the bottom, which is convenient for concentrating the generated solid impurities and discharging them from the reaction tank uniformly through the slag discharge pipe, avoiding the turbidity or even viscosity caused by the alkali hydrolysis of wastewater. The wastewater containing a large amount of solid impurities is temporarily stored in the collection tank and separated into solid and liquid by a solid-liquid separator, which is convenient for the separate treatment of solid impurities. A heater is installed at the position of the inclined enclosure. The liquid flowing downward at the heater is guided by the inclined surface and quickly contacts the wastewater entering through the water inlet pipe. The vertical enclosure increases the height of the mouth edge to ensure that the heater is completely immersed in the wastewater.

[0020] Further, the heater includes a top frame fixed to the top of the reaction tank. A relay frame is slidably installed below the top frame, and a bottom frame is fixedly installed below the relay frame. The relay frame is connected to the top frame by an actuating member. The first corrugated plate and the second corrugated plate are installed between the relay frame and the bottom frame by a limiting member.

[0021] Through the above technical solution, the sliding mode of the heater is disclosed. The top frame is a fixed member directly fixed to the top of the vertical enclosure. The relay frame is slidably connected to the top frame through a guide rail. The first corrugated plate and the second corrugated plate are suspended on the front and rear sides of the electric heating plate. The actuating member is fixed to the top frame as a power source and can drive the relay frame to slide left and right, thereby driving the first corrugated plate and the second corrugated plate to slide left and right. The limiting member is located at the edges of the top and bottom ends of the first corrugated plate and the second corrugated plate. With the support of the bottom frame, the installation stability of the first corrugated plate and the second corrugated plate is ensured.

[0022] Further, the limiting member includes a central axis vertically arranged. A swing frame is rotatably installed outside the central axis. A side axis is rotatably installed through the end of the swing frame. Reinforcing rods are installed at the ends of the first corrugated plate and the second corrugated plate, and the top and bottom ends of the reinforcing rods are respectively fixedly connected to the ends of the side axis.

[0023] Through the above technical solution, to adapt to the wavy side surface of the electric heating plate, the first corrugated plate and the second corrugated plate are also designed to be corrugated and connected by a swing frame. The central axis is located above the electric heating plate and installed on it. The first corrugated plate and the second corrugated plate are strengthened at the edges by the reinforcing rods to avoid deformation. And when the first corrugated plate and the second corrugated plate move left and right, the swing frame rotates, so that the wavy side surface, the first contact surface and the second contact surface are always parallel and in contact. The lower ends of the wavy side surface, the first contact surface and the second contact surface all incline to the left, which is consistent with the inclination angle of the inclined enclosure, ensuring that when the water passing gap is squeezed out, an inclined downward jet can be generated, and reducing the turbulence can ensure the jet velocity, improving the mixing efficiency and the heat dissipation range.

[0024] Further, a tension spring is installed between the swing frame and the central axis. The two ends of the tension spring are respectively installed with a first end rod and a second end rod. The central axis is located directly above the electric heating plate. The two first end rods are symmetrically arranged on both sides of the electric heating plate. The two second end rods are respectively installed near the side axis on the top surface of the swing frame. The two tension springs are respectively installed between the first end rod and the second end rod on different sides of the electric heating plate.

[0025] Through the above technical solution, to ensure that the first corrugated plate and the second corrugated plate are always in close contact, the tension spring is stretched and installed between the first end rod and the second end rod. During the left and right movement of the first corrugated plate and the second corrugated plate, when the wave crests of the first contact surface and the second contact surface contact the wave crest of the wavy side surface, the tension spring is further stretched to adapt to the displacement generated by the mutual separation of the first corrugated plate and the second corrugated plate. When the wave troughs of the first contact surface and the second contact surface contact the wave trough of the wavy side surface, the tension spring rebounds and shortens to adapt to the displacement generated by the mutual approach of the first corrugated plate and the second corrugated plate. The elasticity of the tension spring is used to adapt to the distance change between the first corrugated plate and the second corrugated plate, and an elastic initial pressure can be applied to the electric heating plate to ensure the cleaning effect of scraping.

[0026] A method for treating epichlorohydrin wastewater comprises the following steps:

[0027] The wastewater containing epichlorohydrin is introduced into two preparation ponds for storage. The wastewater in the two preparation ponds is respectively introduced into the monomer pond at the uppermost stream in the lye addition combined pond through two liquid supply pipes, and then flows through a plurality of serially connected monomer ponds in sequence through the overflow ports;

[0028] During the process of the wastewater flowing through the monomer pond, the lye in the liquid storage tank is quantitatively added into the monomer pond by a metering pump and mixed with the wastewater. The first guiding member reduces the flow dead zone below the water outlet of the liquid supply pipe and the water outlet of the adding pipe, increases the flow velocity at the liquid inlet position, and rotates the liquid in the monomer pond through a stirrer. The first guiding member itself adopts an elastic conjunctival structure and will reciprocally deform under the impact of the intermittent water flow generated by the stirrer, pushing the newly entered high-concentration wastewater and lye in the monomer pond towards the stirrer, and quickly mixing with the mixed liquid in the monomer pond, so that the pH value of the wastewater in the downstream monomer pond is adjusted to the range required for the alkaline hydrolysis of epichlorohydrin;

[0029] During the pH value adjustment process, the first guiding member is not installed at the place where the solid collector is installed in the monomer pond, forming a right-angle included angle to reduce the flow velocity of the wastewater here. Part of the solid products generated by the alkaline hydrolysis of epichlorohydrin sink and are centrally collected by the solid collector, and are transported to the collection tank to wait for centralized treatment by the solid-liquid separator, preventing accumulation in the monomer pond and causing a reduction in capacity;

[0030] The wastewater enters the reaction tank and is heated for alkaline hydrolysis through a heater. Part of the upper clear liquid flows into the temporary storage tank through the water outlet pipe, is transported to the monomer pond at the lowermost stream to add lye and then flows back to the reaction tank to ensure that the pH value is stable in the optimal range during the alkaline hydrolysis process;

[0031] The moving part drives the corrugated plate 1 and the corrugated plate 2 to reciprocate along the electric heating plate. When the wave crests of the contact surface 1 and the contact surface 2 contact the wave crests of the wavy side surface, a water passing gap is formed between the corrugated plate 1, the corrugated plate 2 and the electric heating plate. The wastewater on the upper layer flows into the water passing gap and is wrapped and heated. When the wave troughs of the contact surface 1 and the contact surface 2 contact the wave troughs of the wavy side surface, the limiting part can make the water passing gap between the corrugated plate 1, the corrugated plate 2 and the electric heating plate squeeze and disappear, squeeze and eject the wastewater in the up and down directions, form a jet flow and mix with the wastewater far from the electric heating plate, and use the ejected wastewater for heat diffusion to ensure the consistency of heat in the reaction tank and the uniform mixing of wastewater. The limiting part makes the corrugated plate 1 and the corrugated plate 2 always contact the electric heating plate. The heating area is increased through the corrugated plate 1 and the corrugated plate 2. The corrugated plate 1 and the corrugated plate 2 reciprocate, and can scrape the wavy side surface to clean the solid on the surface of the electric heating plate. The solid products on the lower layer will also be led out by the slag discharge pipe;

[0032] After sufficient alkali hydrolysis, the wastewater is introduced into the neutralization tank, the pH value is adjusted by adding acid solution, and then introduced into the biological tank to avoid the influence of epichlorohydrin and alkali solution on the survival of microorganisms in the biological tank.

[0033] The beneficial effects of the present invention are as follows:

[0034] Through the setting of the alkali solution adding combined tank and the reaction tank in the present invention, when adding alkali solution, the series-connected monomer tanks can add alkali solution in batches, gradually adjust the wastewater to the required pH value. In the alkali hydrolysis stage, a circulating water path is formed between the monomer tank downstream and the reaction tank. The wastewater can be supplemented with alkali solution in time during the circulating flow to ensure the stability of the pH value. The vertical arrangement of the heater can also be combined with the circulating flow to make the wastewater fully mixed and uniformly heated. The stability of the temperature and the rationality of the pH value improve the alkali hydrolysis efficiency;

[0035] Through the design of the heater in the present invention, during the alkali hydrolysis reaction process, the electric heating plate provides heat. The corrugated plate 1 and the corrugated plate 2 are always in contact with the heater. The solid impurities on the surface of the heater are cleaned by the sliding of the corrugated plate 1 and the corrugated plate 2, preventing poor heat conduction and being more energy-saving. In the corrugated structure, when the wave crests are superposed and the wave troughs are superposed, a water passing gap that appears and disappears intermittently can be generated on the vertical side wall of the heater, generating intermittent jet flows at the heater, assisting in solid cleaning and increasing the flow mixing efficiency between the upper and lower layers of wastewater, so that the wastewater on the lower layer can also be stably heated, further improving the alkali hydrolysis efficiency. Description of the Drawings

[0036] Figure 1 is the first perspective structure diagram of the present invention;

[0037] Figure 2 is the second perspective structure diagram of the present invention;

[0038] Figure 3 It is a schematic structural diagram of the lye addition combined pool of the present invention;

[0039] Figure 4 It is a schematic structural diagram of the monomer pool in the lye addition combined pool of the present invention;

[0040] Figure 5 It is a cutting schematic diagram of the monomer pool in the lye addition combined pool of the present invention;

[0041] Figure 6 It is a schematic structural diagram of the solid collector in the lye addition combined pool of the present invention;

[0042] Figure 7 It is a sectional view of the reaction pool of the present invention;

[0043] Figure 8 It is a schematic structural diagram of the heater of the present invention;

[0044] Figure 9 It is a schematic diagram of the partial structure of the heater of the present invention;

[0045] Figure 10 It is a partial cutting schematic diagram of the heater of the present invention.

[0046] Reference numerals: 1, preparation pool; 11, liquid supply pipe; 2, lye addition combined pool; 21, monomer pool; 211, overflow port; 22, liquid storage tank; 23, temporary storage tank; 24, addition pipe; 25, stirrer; 26, return pipe; 27, solid collector; 271, housing; 272, communication port; 273, auger blade; 274, semi-circular groove; 275, vertical plate; 276, mesh plate; 277, semi-circular surface; 28, guide member 1; 281, cavity; 29, guide member 2; 3, reaction pool; 31, vertical enclosure; 32, water inlet pipe; 33, bottom shell; 34, cavity; 35, slag discharge pipe; 36, inclined enclosure; 37, water outlet pipe; 4, biological pool; 5, solid-liquid separator; 6, neutralization pool; 7, collection tank; 8, heater; 81, top frame; 82, relay frame; 83, actuating member; 84, corrugated plate 1; 841, contact surface 1; 85, electric heating plate; 851, wavy side surface; 852, water passing gap; 86, corrugated plate 2; 861, contact surface 2; 87, limiting member; 871, tension spring; 872, end rod 1; 873, end rod 2; 874, central axis; 875, side axis; 876, swing frame; 88, strengthening rod; 89, bottom frame. Detailed implementation manners

[0047] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0048] As Figure 1 - Figure 10 shown, this embodiment provides an epichlorohydrin wastewater treatment device, including a preparation tank 1 and a biological tank 4. For the biological treatment of epichlorohydrin wastewater, it is necessary to remove epichlorohydrin first. The actual problem solved by this solution is how to separate and treat epichlorohydrin in a more energy-saving and efficient manner to avoid affecting the normal operation of the biological tank 4.

[0049] Specifically, it includes an alkali solution addition combined tank 2 connected in series between the preparation tank 1 and the biological tank 4 and a reaction tank 3 with a heater 8. By means of alkali hydrolysis, the hardly biodegradable epichlorohydrin can be alkali-hydrolyzed into organic substances containing hydroxyl groups, removing halogen elements and generating solid impurities (such as chloride salts: sodium chloride, potassium chloride; organic solid impurities: organic polymers or oligomers generated during the alkali hydrolysis process, organic by-products such as alcohols and ethers that may be generated during the alkali hydrolysis process; metal hydroxides: if the wastewater contains metal ions such as iron and aluminum, they may react with the alkali to form corresponding metal hydroxide precipitates), reducing the toxicity of the wastewater. During operation, referring to Figure 3 , the alkali solution addition combined tank 2 includes multiple monomer tanks 21 and corresponding storage tanks 22. At least four monomer tanks 21 are used. The multiple monomer tanks 21 are connected in series through overflow ports 211. When adding alkali solution, the alkali solution can be added in batches by connecting multiple monomer tanks 21 in series. With a pH sensor, the wastewater can be gradually adjusted to the required pH value (the pH value is measured by the pH sensor), preventing uneven mixing caused by adding a large amount of alkali solution in a short time. The continuous addition in small amounts and multiple times ensures high adjustment accuracy, saves the dosage of alkali solution while ensuring a reasonable pH value. During the alkali hydrolysis stage, regarding the reaction tank 3, referring to Figure 2 and Figure 7 , a circulating water path is formed between the downstream monomer tank 21 and the reaction tank 3 through a reflux pipe 26 and a water inlet pipe 32. The reaction tank 3 is connected to the biological tank 4 through a water outlet pipe 37. The wastewater in the most downstream monomer tank 21 will circulate through. The wastewater circulates between the downstream monomer tank 21 and the reaction tank 3, timely replenishing the consumed alkali solution to ensure the stability of the pH value. It can also be combined with the vertical arrangement of the heater 8 through circulating flow to fully mix and evenly heat the wastewater. The stability of the temperature and the reasonableness of the pH value reduce the time required for alkali hydrolysis;

[0050] During the pH value adjustment and the circulating alkali hydrolysis process, solid impurities will be carried into the monomer tank 21. The bottom of the monomer tank 21 is connected through a solid collector 27 to timely collect and discharge the solid impurities from the monomer tank 21, avoiding problems such as reduced capacity and pipeline blockage caused by accumulation;

[0051] To further ensure the high efficiency and energy saving of alkali hydrolysis, a specific configuration of the heater 8 is disclosed. Referring to Figure 7and Figure 8 , a heater 8 located in the reaction tank 3. The heater 8 includes a vertically arranged electric heating plate 85. During the alkali hydrolysis reaction, a corrugated plate 84 and a corrugated plate 86 that can slide horizontally along the extending direction of the electric heating plate 85. The corrugated plate 84 and the corrugated plate 86 are connected by a limiting member 87. The limiting member 87 makes the corrugated plate 84 and the corrugated plate 86 always in contact with the heater 8. By using the sliding of the corrugated plate 84 and the corrugated plate 86, the solid impurities on the surface of the heater 8 are cleaned, ensuring the heating efficiency, reducing the energy waste caused by poor energy conduction, and being more energy-saving. At the same time, referring to Figure 9 and Figure 10 , the vertical side wall of the electric heating plate 85 has a wavy side surface 851. The corrugated plate 84 and the corrugated plate 86 are provided with a contact surface 841 and a contact surface 861 corresponding to the position of the wavy side surface 851. In the corrugated structure, when the wave crests are superposed and the wave troughs are superposed, intermittent water passing gaps 852 that appear and disappear between the corrugated plate 84 and the corrugated plate 86 and the heater 8 can be generated. Cooperating with the flow of the wastewater, intermittent jets are generated at the heater 8, assisting in solid cleaning and increasing the flow mixing efficiency between the upper and lower layers of the wastewater, so that the wastewater in the lower layer can also be stably heated, further improving the alkali hydrolysis efficiency. And the corrugated plate 84 and the corrugated plate 86 are made of good heat conductors, which can increase the effective contact area between the heater 8 and the wastewater through the corrugated plate 84 and the corrugated plate 86, and the epichlorohydrin in the alkali-hydrolyzed wastewater is decomposed, avoiding affecting the survival of microorganisms and the decomposition of organic matter when input into the biological tank 4 with the wastewater.

[0052] In a further embodiment, to improve the mixing efficiency, referring to Figure 4 and Figure 5 , the preparation tank 1 is connected to the upstream monomer tank 21 through a liquid supply pipe 11 for the entry of the wastewater to be treated. The storage tank 22 is connected to the monomer tank 21 through an addition pipe 24 to introduce a high-concentration alkali solution. A cavity 281 is formed by enclosing between the guiding member 28, the monomer tank 21 and the guiding member 29. The water outlet of the return pipe 26, the water outlet of the liquid supply pipe 11 and the water outlet of the addition pipe 24 are arranged close to the top surface of the guiding member 28. And the guiding member 28 adopts an elastic membrane structure to eliminate the dead corner area below the liquid supply pipe 11 and the addition pipe 24. The incoming high-concentration wastewater and alkali solution quickly enter the middle of the monomer tank 21 under the guidance of the guiding member 28. A stirrer 25 is arranged in the monomer tank 21. When the stirrer 25 works, the guiding member 28 will collapse due to the impact of the wastewater because of the existence of the cavity 281, and when it rebounds, it will push the liquid above the guiding member 28 close to the stirrer 25, so that the continuously incoming high-concentration wastewater and alkali solution are quickly added to the stirring and mixing.

[0053] In a further embodiment, referring to Figure 5, the monomer tank 21 adopts a rectangular structure. A first guide member 28 is built in at the corner of the monomer tank 21 opposite to the solid collector 27. The first guide member 28 is not installed at the inner corner of the monomer tank 21 where the solid collector 27 is located, so that a slow-flow range can be reserved at the solid collector 27 to enable more effective sedimentation of solid impurities and be collected by the solid collector 27. Among them, a second guide member 29 is installed between the first guide member 28 and the inner wall of the bottom end of the monomer tank 21. The second guide member 29 has an inclined top surface, and the lowest point of the inclined top surface of the second guide member 29 is located at the solid collector 27. The inclined designs of the first guide member 28 and the second guide member 29 will guide the generated solid impurities to the position of the solid collector 27, centrally collect the entrained and newly generated solid impurities, and quickly discharge them from the monomer tank 21 to avoid continuous accumulation.

[0054] In a further embodiment, a specific solid collector 27 is disclosed. Referring to Figure 5 and Figure 6 , the solid collector 27 includes a housing 271. A communication port 272 is provided on the vertical side wall of the housing 271 inside the monomer tank 21. The communication port 272 faces the lowest point of the second guide member 29, so that solid impurities can enter the housing 271 more conveniently. A plurality of vertical plates 275 are installed in the communication port 272 of the housing 271. A screw blade 273 is installed between the housing 271 and the vertical plates 275. A semi-circular arc groove 274 is provided on the inner wall of the housing 271 corresponding to the screw blade 273. A semi-circular arc surface 277 is provided on the vertical plate 275 corresponding to the screw blade 273. A mesh plate 276 is provided above the screw blade 273 on the housing 271. When adjusting the pH value, when the screw blade 273 does not rotate, the wastewater entering the housing 271 will flow upward from the mesh plate 276 and out of the housing 271. The screw blade 273 acts as a baffle. The solid impurities settle in the semi-circular arc groove 274 under the friction and blockage of the vertical plate 275 and the screw blade 273. When the solid impurities need to be discharged, the screw blade 273 rotates, and the collected solid impurities can be discharged from the outlet at the right end by using the spiral structure of the screw blade 273. The vertical plate 275 plays a limiting role to prevent the screw blade 273 from slipping out of the semi-circular arc groove 274 and ensure the stable rotation of the screw blade 273.

[0055] In a further embodiment, to ensure the pH value control during the alkali hydrolysis process, at this time, other monomer tanks 21 stop working, and the preparation tank 1 also stops inputting new wastewater. Referring to Figure 3, a temporary storage tank 23 is provided between the reflux pipe 26 and the middle monomer pool 21. A three-way valve is installed at the connection between the reflux pipe 26 and the water outlet pipe 37, integrating the most downstream monomer pool 21 and the reaction pool 3. The reflux pipe 26 and the water outlet pipe 37 form a water passing loop therebetween, enabling the wastewater in the reaction pool 3 to flow back into the monomer pool 21, carrying the lye into the reaction pool 3 for rapid lye supplementation. It can alternately flow through the position of the heater 8 for heating to ensure the stable heat of the wastewater. It can also make the wastewater in the reaction pool 3 be disturbed and mixed through cyclic flow, shortening the time required for alkali hydrolysis. At the same time, referring to Figure 2 , the water outlet pipe 37 is connected to a neutralization tank 6 through a three-way valve. After the alkali hydrolysis ends, the wastewater is introduced into the neutralization tank 6 and neutralized by adding acid solution. The neutralization tank 6 is located upstream of the biological tank 4 to ensure that the wastewater entering the biological tank 4 is neutral.

[0056] In a further embodiment, a specific configuration of the reaction pool 3 is disclosed. Referring to Figure 7 , the reaction pool 3 includes a bottom shell 33, which is wider at the top and narrower at the bottom, facilitating the concentration of the generated solid impurities and uniformly discharging them from the reaction pool 3 through the slag discharge pipe 35, avoiding the turbidity or even viscosity caused by the alkali hydrolysis of the wastewater. Among them, a slag discharge pipe 35 is installed at the bottom of the bottom shell 33. Referring to Figure 1 , the outlets of the solid collector 27 and the slag discharge pipe 35 are connected to a collection tank 7 through a pipeline. The collection tank 7 is connected to a solid-liquid separator 5 through a pipeline. The wastewater containing a large amount of solid impurities is temporarily stored in the collection tank 7 and undergoes solid-liquid separation through the solid-liquid separator 5, facilitating the separate treatment of the solid impurities. And, referring to Figure 7 , an inclined enclosure 36 is provided at the opening position at the top of the bottom shell 33, and a vertical enclosure 31 is provided at the opening position at the top of the inclined enclosure 36. The bottom shell 33, the inclined enclosure 36 and the vertical enclosure 31 enclose a cavity 34 with an upward opening. The heater 8 is installed at the position of the inclined enclosure 36. The liquid flowing downward at the heater 8 will be guided by the inclined surface and flow left and downward, quickly contacting the wastewater entering through the water inlet pipe 32. The vertical enclosure 31 increases the height of the mouth edge to ensure that the heater 8 is completely immersed in the wastewater.

[0057] In a further embodiment, the sliding mode of the heater 8 is disclosed. Referring to Figure 8, the heater 8 includes a top frame 81 which is fixed to the top of the reaction tank 3. The top frame 81 is a fixing member and is directly fixed to the top of the vertical enclosure 31. A relay frame 82 is slidably installed below the top frame 81. The relay frame 82 is slidably connected to the top frame 81 through a guide rail. The first corrugated plate 84 and the second corrugated plate 86 are suspended on the front and rear sides of the electric heating plate 85. A bottom frame 89 is fixedly installed below the relay frame 82. The first corrugated plate 84 and the second corrugated plate 86 are installed between the relay frame 82 and the bottom frame 89 through a limiting member 87. The limiting member 87 is located at the edges of the top and bottom ends of the first corrugated plate 84 and the second corrugated plate 86. With the support of the bottom frame 89, the installation stability of the first corrugated plate 84 and the second corrugated plate 86 is ensured. The relay frame 82 is connected to the top frame 81 through an actuating member 83. Among them, the actuating member 83 is fixed to the top frame 81 as a power source and can drive the relay frame 82 to slide left and right, and then drive the first corrugated plate 84 and the second corrugated plate 86 to slide left and right. Specifically, the actuating member 83 can be an electric hoist connected with a steel cable. The end of the steel cable is fixed to the relay frame 82. By taking in and releasing the steel cable, horizontal startup can be realized. The actuating member 83 can also adopt a combination of a motor, a motor wheel and a pulling rope. The middle part of the cable is wound around the outside of the motor wheel, and the two ends are respectively fixed to the left and right side walls of the relay frame 82. When the motor works to drive the motor wheel to rotate forward and backward, the relay frame 82 can be driven to slide left and right by winding the cable. The actuating member 83 can also adopt other structures that can realize horizontal reciprocating drive, which will not be elaborated here.

[0058] In a further embodiment, to adapt to the wavy side surface 851 of the electric heating plate 85, refer to Figure 9 , the limiting member 87 includes a central shaft 874 which is vertically arranged. A swing frame 876 is rotatably installed outside the central shaft 874. The first corrugated plate 84 and the second corrugated plate 86 are also designed in a corrugated shape and are connected through the swing frame 876. The central shaft 874 is located above the electric heating plate 85. A side shaft 875 is rotatably installed through the end of the swing frame 876. Reinforcing rods 88 are installed at the ends of the first corrugated plate 84 and the second corrugated plate 86. The top and bottom ends of the reinforcing rods 88 are respectively fixedly connected to the ends of the side shaft 875. The first corrugated plate 84 and the second corrugated plate 86 are strengthened at the edges through the reinforcing rods 88 to avoid deformation. Refer to Figure 10 , when the first corrugated plate 84 and the second corrugated plate 86 move left and right, the swing frame 876 rotates, so that the wavy side surface 851, the first contact surface 841 and the second contact surface 861 are always parallel and in contact. The wavy side surface 851, the first contact surface 841 and the second contact surface 861 are all inclined to the left at the lower end, which is consistent with the inclination angle of the inclined enclosure 36. It is ensured that when the water passing gap 852 is squeezed and disappears, an inclined downward jet flow can be generated, and the reduction of turbulence can ensure the jet flow speed, improve the mixing efficiency and the heat dissipation range.

[0059] In a further embodiment, to ensure that the first corrugated plate 84 and the second corrugated plate 86 are always in close contact, refer to Figure 10, a tension spring 871 is installed between the swing frame 876 and the central shaft 874. The two ends of the tension spring 871 are respectively installed with a first end rod 872 and a second end rod 873. The tension spring 871 is stretched and installed between the first end rod 872 and the second end rod 873. The central shaft 874 is located directly above the electric heating plate 85. The two first end rods 872 are symmetrically arranged on both sides of the electric heating plate 85. The two second end rods 873 are respectively installed near the side shaft 875 on the top surface of the swing frame 876. The two tension springs 871 are respectively installed between the first end rod 872 and the second end rod 873 on different sides of the electric heating plate 85. Among them, during the left and right movement of the first corrugated plate 84 and the second corrugated plate 86, when the wave crests of the first contact surface 841 and the second contact surface 861 contact the wave crest of the wavy side surface 851, the tension spring 871 is further stretched to adapt to the displacement generated by the mutual separation of the first corrugated plate 84 and the second corrugated plate 86. When the wave troughs of the first contact surface 841 and the second contact surface 861 contact the wave trough of the wavy side surface 851, the tension spring 871 rebounds and shortens to adapt to the displacement generated by the mutual approach of the first corrugated plate 84 and the second corrugated plate 86. The elasticity of the tension spring 871 is used to adapt to the change in the distance between the first corrugated plate 84 and the second corrugated plate 86, and an elastic initial pressure can be applied to the electric heating plate 85 to ensure the cleaning effect of scraping.

[0060] A method for treating epichlorohydrin wastewater comprises the following steps:

[0061] The wastewater containing epichlorohydrin is introduced into two preparation tanks 1 for storage. The wastewater in the two preparation tanks 1 is respectively introduced into the monomer tank 21 at the uppermost reaches in the alkali solution addition combined tank 2 through two liquid supply pipes 11, and then flows through a plurality of serially connected monomer tanks 21 in sequence through the overflow port 211;

[0062] During the process of the wastewater flowing through the monomer tank 21, the alkali solution in the liquid storage tank 22 is quantitatively added into the monomer tank 21 by a metering pump and mixed with the wastewater. The first guiding member 28 reduces the flow dead zone below the water outlet of the liquid supply pipe 11 and the water outlet of the addition pipe 24, increases the flow velocity at the liquid inlet position, and rotates the liquid in the monomer tank 21 through the stirrer 25. The first guiding member 28 itself adopts an elastic conjunctival structure and will reciprocally deform under the impact of the intermittent water flow generated by the stirrer 25, and squeezes and pushes the newly introduced high-concentration wastewater and alkali solution in the monomer tank 21 towards the stirrer 25, and quickly mixes with the mixed liquid in the monomer tank 21, so that the pH value of the wastewater in the downstream monomer tank 21 is adjusted to the range required for the alkali hydrolysis of epichlorohydrin;

[0063] During the pH value adjustment process, no guide piece 1 (28) is installed at the solid collector 27 in the monomer pool 21, forming two right - angle angles, which reduces the flow rate of the wastewater here. Part of the solid products generated by the alkaline hydrolysis of epichlorohydrin sink. When flowing through the stationary auger blade 273, the liquid rises while the solid is frictionally decelerated and settled, and is centrally collected by the solid collector 27. Then it is pushed to the right by the rotation of the auger blade 273 and finally transported to the collection tank 7 to wait for centralized treatment by the solid - liquid separator 5, preventing accumulation in the monomer pool 21 and causing a reduction in capacity;

[0064] The wastewater enters the reaction tank 3 and is heated and alkali - hydrolyzed by the heater 8. Part of the supernatant liquid flows into the temporary storage tank 23 from the water outlet pipe 37, and then alkali liquor is added in the monomer pool 21 at the most downstream and flows back into the reaction tank 3. With the consumption of the alkali liquor, timely replenishment is carried out to ensure that the pH value during the alkali - hydrolysis process is stable within the optimal range, and it can make the wastewater flow horizontally, ensuring that the wastewater flows into contact with the heater 8, improving the heating uniformity, and ensuring the stability of the reaction temperature;

[0065] The actuating part 83 drives the corrugated plate 1 (84) and the corrugated plate 2 (86) to slide reciprocally along the electric heating plate 85. When the peaks of the contact surface 1 (841) and the peaks of the contact surface 2 (861) contact the peaks of the wavy side surface 851, a water - passing gap 852 is formed between the corrugated plate 1 (84), the corrugated plate 2 (86) and the electric heating plate 85. The upper - layer wastewater flows into the water - passing gap 852 and is wrapped and heated by the corrugated plate 1 (84), the corrugated plate 2 (86) and the electric heating plate 85. When the troughs of the contact surface 1 (841) and the troughs of the contact surface 2 (861) contact the troughs of the wavy side surface 851, the limiting part 87 can make the water - passing gap 852 between the corrugated plate 1 (84), the corrugated plate 2 (86) and the electric heating plate 85 squeeze and disappear, squeezing and spraying the wastewater in the up - and - down directions to form a jet flow and mix with the wastewater far from the electric heating plate 85, and using the sprayed wastewater for heat diffusion, making the wastewater flow up and down, thereby ensuring the temperature stability of the wastewater at different depths, preventing the lower - layer wastewater from having a lower temperature due to being far from the heater 8, ensuring the consistency of the heat in the reaction tank 3 and the uniform mixing of the wastewater, thereby improving the alkali - hydrolysis efficiency, shortening the alkali - hydrolysis time. The elastic compensation of the limiting part 87 makes the corrugated plate 1 (84) and the corrugated plate 2 (86) always contact the electric heating plate 85. The corrugated plate 1 (84) and the corrugated plate 2 (86) are made of heat - conductive materials, which can greatly increase the effective heating area of the wastewater. Because the corrugated plate 1 (84) and the corrugated plate 2 (86) slide reciprocally, they can scrape the wavy side surface 851 to clean the surface of the electric heating plate 85 of solids, avoiding the reduction of the thermal efficiency caused by the accumulation of solids on the surface of the electric heating plate 85. The lower - layer solid products will also be led out by the slag discharge pipe 35;

[0066] After the epichlorohydrin is fully alkali-hydrolyzed, the wastewater is introduced into the neutralization tank 6, and the pH value is adjusted by adding acid solution. During the process, it is monitored by a pH sensor to avoid the pH value being lower than 7, ensuring the neutrality of the wastewater, and then introduced into the biological tank 4 for the treatment of other organic wastes by microorganisms, avoiding the influence of epichlorohydrin and alkali solution on the survival of microorganisms in the biological tank 4.

[0067] The above is only the preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.

Claims

1. An epichlorohydrin wastewater treatment device, comprising a preparation tank (1) and a biological tank (4), characterized in that: Also includes: an alkali solution addition combined pool (2) connected in series between the preparation pool (1) and the biological pool (4), the alkali solution addition combined pool (2) comprising a plurality of monomer pools (21) and a corresponding number of liquid storage tanks (22), the plurality of monomer pools (21) being connected in series via an overflow port (211), and a solid collector (27) being connected through the bottom of the monomer pool (21); A reaction pool (3) is connected in series between the alkali solution addition combined pool (2) and the biological pool (4); the monomer pool (21) at the downstream forms a circulating water path with the reaction pool (3) through a reflux pipe (26) and a water inlet pipe (32); and the reaction pool (3) and the biological pool (4) are connected through a water outlet pipe (37); A heater (8) is located in the reaction tank (3), the heater (8) comprising a vertically arranged electric heating plate (85), and a corrugated plate 1 (84) and a corrugated plate 2 (86) capable of horizontally sliding along the extension direction of the electric heating plate (85), the corrugated plate 1 (84) and the corrugated plate 2 (86) being connected via a stopper (87), the vertical side wall of the electric heating plate (85) having a wavy side surface (851), and the corrugated plate 1 (84) and the corrugated plate 2 (86) having a contact surface 1 (841) and a contact surface 2 (861) at positions corresponding to the wavy side surface (851).

2. The epichlorohydrin wastewater treatment device according to claim 1, characterized in that: The preparation tank (1) is connected to the upstream monomer tank (21) through a liquid supply pipe (11), the liquid storage tank (22) is connected to the monomer tank (21) through an addition pipe (24), a cavity (281) is formed between the guide member 1 (28), the monomer tank (21) and the guide member 2 (29), the water outlet of the reflux pipe (26), the water outlet of the liquid supply pipe (11) and the water outlet of the addition pipe (24) are arranged close to the top surface of the guide member 1 (28), and the monomer tank (21) is provided with a built-in agitator (25).

3. The epichlorohydrin wastewater treatment device according to claim 2, characterized in that: The monomer pool (21) adopts a rectangular structure, the guide member 1 (28) is located at the corner of the monomer pool (21) opposite to the solid collector (27), the guide member 2 (29) is installed between the guide member 1 (28) and the inner wall of the bottom end of the monomer pool (21), the guide member 2 (29) has an inclined top surface, and the solid collector (27) is installed at the lowest point of the inclined top surface of the guide member 2 (29).

4. The epichlorohydrin wastewater treatment device according to claim 3, characterized in that: The solid collector (27) comprises a shell (271), wherein the shell (271) is provided with a communication port (272) at a vertical side wall located on the inner side of the monomer tank (21), wherein a plurality of vertical plates (275) are installed in the shell (271) in the communication port (272), wherein an auger blade (273) is installed between the shell (271) and the vertical plates (275), wherein a semi-circular arc groove (274) is provided on the inner wall of the shell (271) corresponding to the auger blade (273), wherein a semi-circular arc surface (277) is provided on the vertical plates (275) corresponding to the auger blade (273), and wherein a mesh plate (276) is provided on the shell (271) directly above the auger blade (273).

5. The epichlorohydrin wastewater treatment device according to claim 4, characterized in that: A temporary storage tank (23) is provided between the reflux pipe (26) and the middle monomer pool (21), a three-way valve is installed at the connection point between the reflux pipe (26) and the outlet pipe (37), the outlet pipe (37) is connected to the neutralization pool (6) through the three-way valve, and the neutralization pool (6) is located upstream of the biological pool (4).

6. The epichlorohydrin wastewater treatment device according to claim 5, characterized in that: The reaction tank (3) comprises a bottom shell (33), the top opening position of the bottom shell (33) is provided with an oblique enclosure (36), the top opening position of the oblique enclosure (36) is provided with a vertical enclosure (31), the bottom shell (33), the oblique enclosure (36) and the vertical enclosure (31) are arranged to form a cavity (34) opening upward, a slag discharge pipe (35) is installed at the bottom of the bottom shell (33), the outlet of the solid collector (27) and the outlet of the slag discharge pipe (35) are connected to a collection tank (7) through a pipeline, and the collection tank (7) is connected to a solid-liquid separator (5) through a pipeline.

7. The epichlorohydrin wastewater treatment device according to claim 1, characterized in that: The heater (8) comprises a top frame (81), wherein the top frame (81) is fixed on the top of the reaction pool (3), a relay frame (82) is slidably mounted below the top frame (81), a bottom frame (89) is fixedly mounted below the relay frame (82), the relay frame (82) and the top frame (81) are connected via an actuating member (83), and the corrugated plate 1 (84) and the corrugated plate 2 (86) are mounted between the relay frame (82) and the bottom frame (89) via a limiting member (87).

8. The epichlorohydrin wastewater treatment device according to claim 7, characterized in that: The limiting member (87) includes a central axis (874) which is vertically arranged. A swing frame (876) is rotatably mounted on the outer side of the central axis (874). A side axis (875) is rotatably mounted through the end of the swing frame (876). Reinforcing rods (88) are mounted on the ends of the corrugated plate 1 (84) and the corrugated plate 2 (86). The top and bottom ends of the reinforcing rods (88) are respectively fixedly connected to the ends of the side axis (875).

9. The epichlorohydrin wastewater treatment device according to claim 8, characterized in that: The invention comprises a swing frame (876), a tension spring (871) is installed between the swing frame (876) and the central axis (874), an end rod 1 (872) and an end rod 2 (873) are installed at both ends of the tension spring (871), the central axis (874) is located directly above the electric heating plate (85), the two end rods 1 (872) are symmetrically arranged on both sides of the electric heating plate (85), the two end rods 2 (873) are installed on the top surface of the swing frame (876) close to the side axis (875), and the two tension springs (871) are installed between the end rod 1 (872) and the end rod 2 (873) located on different sides of the electric heating plate (85).

10. A method for treating epichlorohydrin wastewater, according to the epichlorohydrin wastewater treatment device according to claim 6, characterized in that: The wastewater containing epichlorohydrin is introduced into two preparation tanks (1) for storage. The wastewater in the two preparation tanks (1) is respectively introduced into the upstreammost monomer tank (21) in the alkali solution addition combination tank (2) through two liquid supply pipes (11), and then flows through the overflow port (211) in sequence through the plurality of monomer tanks (21) connected in series. When the wastewater flows through the monomer pool (21), the alkali solution in the liquid storage tank (22) is quantitatively added into the monomer pool (21) by the metering pump to mix with the wastewater. The guide member 1 (28) reduces the dead zone of the flow below the outlet of the liquid supply pipe (11) and the outlet of the addition pipe (24). The guide member 1 (28) itself adopts an elastic conjunctival structure and is reciprocally deformed by the impact of the intermittent water flow generated by the stirrer (25), so that the newly high-concentration wastewater and alkali solution entering the monomer pool (21) are squeezed and pushed toward the stirrer (25), so that the pH value of the wastewater in the downstream monomer pool (21) is adjusted to the range required for the alkaline hydrolysis of epichlorohydrin. During the pH value adjustment process, the guide member 1 (28) is not installed at the location where the solid collector (27) is installed in the monomer pool (21), so that the solid products generated by the alkaline hydrolysis of epichlorohydrin sink and are collected by the solid collector (27) and transported to the collection tank (7) to be processed by the solid-liquid separator (5); The wastewater enters the reaction tank (3), is heated and alkaline hydrolyzed by the heater (8), and part of the upper clear liquid flows into the temporary storage tank (23) from the outlet pipe (37), is transported to the monomer tank (21) at the most downstream, and then alkaline liquid is added and flows back to the reaction tank (3), so as to ensure that the pH value is stable in the optimal range during the alkaline hydrolysis process; The action member (83) drives the corrugated plate 1 (84) and the corrugated plate 2 (86) to slide back and forth along the electric heating plate (85), forming an intermittent water gap (852) between the corrugated plate 1 (84) and the corrugated plate 2 (86) and the electric heating plate (85), squeezing and spraying the wastewater in the upward and downward directions to form a jet flow that mixes with the wastewater away from the electric heating plate (85). The limiting member (87) makes the corrugated plate 1 (84) and the corrugated plate 2 (86) always contact the electric heating plate (85), thereby increasing the heating area and scraping the wavy side surface (851) to clean the solid on the surface of the electric heating plate (85); After sufficient alkaline hydrolysis, the wastewater is introduced into a neutralization tank (6), and the pH value is adjusted by adding acid, and then introduced into a biological tank (4) to prevent epichlorohydrin and alkaline solution from affecting the survival of microorganisms in the biological tank (4).

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