Alcohol-containing wastewater pretreatment system

Abstract

The utility model discloses an alcohol-containing wastewater pretreatment system which comprises an aeration sedimentation tank, a produced water outlet of the aeration sedimentation tank is communicated with a low-temperature wet oxidation reactor, a produced water outlet of the low-temperature wet oxidation reactor is communicated with a chemical sedimentation tank, and a produced water outlet of the chemical sedimentation tank is communicated with an ammonia nitrogen stripping tower. A produced water outlet of the ammonia nitrogen stripping tower is communicated with an AO biochemical reaction system, and a biochemical sludge outlet of the AO biochemical reaction system is communicated with a sludge inlet of the aeration sedimentation tank. Through the aeration sedimentation tank, the low-temperature wet oxidation reactor, the chemical sedimentation tank and the ammonia nitrogen stripping tower which are communicated in sequence, substances such as suspended solids, sulfur-containing impurities and nitrogen-containing organic impurities and part of organic matters in the alcohol-containing wastewater are removed, the influence of the substances on microorganisms is eliminated, normal and effective operation of an AO biochemical reaction system is ensured, and the treatment effect of the AO biochemical reaction system is improved. The alcohol-containing wastewater treatment efficiency and quality are improved.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology, specifically to a pretreatment system for alcohol-containing wastewater. Background Technology

[0002] Alcohol-containing wastewater refers to wastewater containing alcoholic chemicals (such as ethanol and isopropanol) generated during the production, processing, use, or other industrial processes. During the production and use of alcohols, due to impurities in various raw materials, reaction byproducts, and solvent residues, alcohol-containing wastewater contains a wide variety of pollutants. These include sulfur-containing impurities such as thiourea, thiols, isothiocyanates, and thiocyanate, as well as nitrogen-containing organic impurities such as amines and nitrogen-containing aromatic compounds. These impurities directly interfere with the metabolic processes of microorganisms in the biochemical system, reducing their ability to degrade organic matter and even leading to microbial death. Therefore, alcohol-containing wastewater needs to undergo pretreatment using various methods before entering the biochemical unit to eliminate the impact of these substances on microorganisms. Utility Model Content

[0003] The purpose of this invention is to provide a pretreatment system for alcohol-containing wastewater, which can effectively treat impurities in alcohol-containing wastewater and ensure the normal and effective operation of biochemical treatment.

[0004] This utility model is implemented by the following technical solution:

[0005] An alcohol-containing wastewater pretreatment system includes an aerated settling tank with a wastewater inlet and a sludge inlet. The alcohol-containing wastewater first enters the aerated settling tank, where pre-aeration increases dissolved oxygen, strips volatile pollutants, and initially oxidizes and reduces substances. The biochemical sludge degrades some organic matter and ammonia nitrogen, and adsorbs suspended solids (SS) from the wastewater. After pre-aeration, the mixed water settles, and the permeate enters the next treatment unit. The permeate outlet of the aerated settling tank is connected to a low-temperature wet oxidation reactor, which oxidizes toxic substances such as sulfides and thiocyanate in the wastewater, while further oxidizing organic matter. The product water outlet of the chemical reactor is connected to a chemical precipitation tank. After the wastewater reacts with the chemical agent, the sulfate substances in it are removed and precipitated. The product water outlet of the chemical precipitation tank is connected to an ammonia nitrogen stripping tower to remove ammonia nitrogen from the wastewater. The product water outlet of the ammonia nitrogen stripping tower is connected to an AO biochemical reaction system. After the aforementioned pretreatment steps, sulfur-containing impurities, nitrogen-containing organic impurities and other substances in the alcohol-containing wastewater are basically removed, solving the problems in the background technology. The product water enters the AO biochemical reaction system for further removal of COD, ammonia nitrogen and nitrate. The biochemical product water then enters the subsequent water treatment process to complete wastewater treatment and recycling.

[0006] Furthermore, the sludge outlet of the AO biochemical reaction system is connected to the sludge inlet of the aerated settling tank, and the sludge after AO biochemical treatment can be directly returned to the aerated settling tank for reuse; the aerated settling tank is provided with a sludge outlet, and the supernatant after settling is used as permeate to enter the low-temperature wet oxidation reactor for treatment, and the sludge is discharged for solid waste treatment.

[0007] Furthermore, the low-temperature wet oxidation reactor is equipped with a pressure gauge and a thermometer; the oxidant inlet of the low-temperature wet oxidation reactor is connected to a hydrogen peroxide storage tank. Under certain temperature and pressure, the wastewater is oxidized and catalytically degraded to remove sulfate substances in the reactor, and most of the chromogenic groups can be degraded and oxidized to reduce COD, resulting in a significant organic matter degradation effect.

[0008] Furthermore, a pH meter is installed in the chemical precipitation tank; the chemical inlet of the chemical precipitation tank is connected to a calcium hydroxide storage tank, SO4 2- + Ca(OH)2→CaSO4↓+ 2OH - It can remove sulfate ions from wastewater and is Cl-free. - The solution is introduced and the pH is adjusted to alkaline to facilitate subsequent ammonia nitrogen stripping. The precipitate is mainly composed of calcium sulfate, which can be discharged, treated, and recycled for reuse.

[0009] Furthermore, a pH meter is installed inside the ammonia nitrogen stripping tower. In the preliminary treatment, under the high temperature and high pressure environment of wet oxidation, ammonia nitrogen is first oxidized to nitrogen oxides, which then undergo the following reaction in this reaction system: NO x +H2O→NH3+O2, so the final product water has less nitrate ions; at the same time, the organic nitrogen in the alcohol-containing wastewater undergoes the following reaction: R-NH2+O2→NH3+CO2, which leads to a further increase in ammonia nitrogen. High ammonia nitrogen will inhibit the activity of nitrifying bacteria enzymes. Therefore, the ammonia nitrogen stripping tower is set up to control the pH at 10~12. Free ammonia nitrogen is stripped by air stripping, and the discharged ammonia gas is treated by an ammonia gas treatment device.

[0010] Beneficial effects:

[0011] This invention provides a pretreatment system for alcohol-containing wastewater. By setting up an aeration sedimentation tank, a low-temperature wet oxidation reactor, a chemical precipitation tank, and an ammonia nitrogen stripping tower connected in sequence, it removes suspended solids, sulfur-containing impurities, nitrogen-containing organic impurities, and some organic matter from the alcohol-containing wastewater, eliminates the impact of the above substances on microorganisms, ensures the normal and effective operation of the AO biochemical reaction system, and improves the treatment efficiency and quality of alcohol-containing wastewater. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of an alcohol-containing wastewater pretreatment system in one of the embodiments.

[0014] The attached diagram is described below:

[0015] 1. Aerated settling tank; 2. Low-temperature wet oxidation reactor; 21. Hydrogen peroxide storage tank; 3. Chemical precipitation tank; 31. Calcium hydroxide storage tank; 4. Ammonia nitrogen stripping tower; 5. AO biochemical reaction system. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "inner", "outer", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Example

[0018] An alcohol-containing wastewater pretreatment system, such as Figure 1 As shown, it includes an aerated sedimentation tank 1, a low-temperature wet oxidation reactor 2, a chemical precipitation tank 3, an ammonia nitrogen stripping tower 4, and an AO biochemical reaction system 5.

[0019] The aeration settling tank 1 may include an aeration tank and a settling tank connected in sequence. The aeration tank is equipped with a wastewater inlet and a sludge inlet. Flow meters and solenoid valves may be installed on the pipelines supplying wastewater and sludge to facilitate proportional control of their entry. After aeration, the mixed water enters the settling tank for sedimentation. A sludge outlet is located at the bottom of the aeration settling tank 1. The product water outlet of the aeration settling tank 1 is connected to a low-temperature wet oxidation reactor 2. The low-temperature wet oxidation reactor 2 is equipped with a pressure gauge and a thermometer. The oxidant inlet of the low-temperature wet oxidation reactor 2 is connected to a hydrogen peroxide storage tank 21. The product water outlet of the low-temperature wet oxidation reactor 2 is connected to a chemical precipitation tank 3. A pH meter is installed in the chemical precipitation tank 3. The chemical agent inlet of the chemical precipitation tank 3 is connected to a calcium hydroxide storage tank 31. The product water outlet of the chemical precipitation tank 3 is connected to an ammonia nitrogen stripping tower 4. A pH meter is installed in the ammonia nitrogen stripping tower 4. The product water outlet of the ammonia nitrogen stripping tower 4 is connected to an AO biochemical reaction system 5. The sludge outlet of the AO biochemical reaction system 5 is connected to the sludge inlet of the aerated settling tank 1; the AO biochemical reaction system 5 may include a bar screen well, equalization tank, sedimentation tank, A-level biological treatment tank (anaerobic tank), O-level biological treatment tank (biological contact oxidation tank), sedimentation tank, disinfection tank, and sludge tank connected in sequence.

[0020] In operation, new sludge or sludge from the AO biochemical reaction system 5 is introduced into the aeration settling tank 1. Alcohol-containing wastewater is then introduced into the aeration settling tank 1 according to the set ratio. After 24 hours of pre-aeration with continuous stirring, dissolved oxygen is increased, volatile pollutants (such as thiols and some amines) are stripped, and preliminary oxidation and reduction of substances are achieved. The biochemical sludge can degrade some organic matter and ammonia nitrogen, and adsorb suspended solids (SS) in the wastewater. After pre-aeration, the mixed water settles, the sludge is discharged for solid waste treatment, and the permeate enters the low-temperature wet oxidation reactor 2. In the low-temperature wet oxidation reactor 2, the pressure is set to 1 MPa and the temperature to 150℃. After 1 hour of reaction, toxic substances such as sulfides and thiocyanate in the wastewater are oxidized, while organic matter is further oxidized. The permeate after oxidation enters the chemical precipitation tank 3. In the chemical precipitation tank 3, the wastewater reacts with calcium hydroxide, producing SO42-. 2- + Ca(OH)₂→CaSO₄↓+2OH⁻ - After the reaction, sulfate ions in the wastewater are removed and precipitated, and the pH is adjusted to alkaline, which is beneficial for subsequent ammonia nitrogen stripping. The precipitate formed after the chemical reaction and precipitation is mainly calcium sulfate, which can be treated and recycled. The permeate enters ammonia nitrogen stripping tower 4. In the preceding low-temperature wet oxidation process, actual experiments showed that ammonia nitrogen is first oxidized to nitrogen oxides, and nitrogen oxides further undergo the following reaction under this reaction system: NO xThe reaction R-NH2 + O2 → NH3 + O2 results in a lower nitrate ion concentration in the final product water. Simultaneously, organic nitrogen in the alcohol-containing wastewater undergoes the following reaction: R-NH2 + O2 → NH3 + CO2, leading to a further increase in ammonia nitrogen. High ammonia nitrogen levels inhibit nitrifying bacteria enzyme activity. Therefore, an ammonia nitrogen stripping tower 4 is installed to treat the wastewater, controlling the pH at 10-12. Free ammonia nitrogen is removed from the wastewater through air stripping. The product water after ammonia nitrogen stripping enters the AO biological reaction system 5. After the aforementioned pretreatment steps, sulfur-containing impurities and nitrogen-containing organic impurities in the alcohol-containing wastewater are largely removed, solving the problems mentioned in the background technology. The product water in the AO biological reaction system 5 can further remove COD, ammonia nitrogen, and nitrate. The sludge is returned to the aerated settling tank 1 for reuse, and the product water is then used in subsequent water treatment processes to complete the wastewater treatment.

[0021] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A pretreatment system for alcohol-containing wastewater, characterized in that, It includes an aerated settling tank, which is equipped with a wastewater inlet and a sludge inlet; the product water outlet of the aerated settling tank is connected to a low-temperature wet oxidation reactor, the product water outlet of the low-temperature wet oxidation reactor is connected to a chemical precipitation tank, the product water outlet of the chemical precipitation tank is connected to an ammonia nitrogen stripping tower, and the product water outlet of the ammonia nitrogen stripping tower is connected to an AO biochemical reaction system.

2. The alcohol-containing wastewater pretreatment system according to claim 1, characterized in that, The sludge outlet of the AO biochemical reaction system is connected to the sludge inlet of the aerated settling tank; a sludge outlet is provided at the bottom of the aerated settling tank.

3. The alcohol-containing wastewater pretreatment system according to claim 1, characterized in that, The low-temperature wet oxidation reactor is equipped with a pressure gauge and a thermometer; the oxidant inlet of the low-temperature wet oxidation reactor is connected to a hydrogen peroxide storage tank.

4. The alcohol-containing wastewater pretreatment system according to claim 1, characterized in that, The chemical precipitation tank is equipped with a pH meter; the chemical inlet of the chemical precipitation tank is connected to a calcium hydroxide storage tank.

5. The alcohol-containing wastewater pretreatment system according to claim 1, characterized in that, A pH meter is installed inside the ammonia stripping tower.

Images