Treatment system and method for food oily wastewater

Abstract

The invention relates to a food oily wastewater treatment system and method.The system comprises a production wastewater collection pipeline and a domestic wastewater collection pipeline, the production wastewater is connected to a rotary drum grillage machine through a pipeline, a water outlet of the rotary drum grillage machine is connected with a water collection lifting pool, and the domestic wastewater is connected to a three-grid septic tank through a pipeline; the water outlet end of the three-grid septic tank is provided with an artificial grid which is connected with the water collection lifting tank and enters the treatment system together with the production wastewater. The front-end process flow is shortened, the residence time and the decomposition opportunity of sludge or residues in sewage are reduced, so that the investment of a subsequent biochemical unit is indirectly reduced, the treatment pressure of the subsequent unit is also relieved, the ABR anaerobic tank with higher inclusiveness is selected as the biochemical treatment unit, the operation and maintenance pressure of enterprises is reduced, and the production cost is reduced. Meanwhile, the multi-stage AO tank is arranged, so that the device is more suitable for high-TN treatment brought by meat food processing, the operation is more stable, and the cost is saved.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and in particular relates to a system and method for treating food oily wastewater. Background Art

[0002] With the development of the country and the improvement of people's pace of life, various pre-processed foods have entered our lives, such as the products produced by Huang Shang Huang, Juewei, Jinzi and other companies. In the processing of various meat or plant foods, oily wastewater is often discharged. According to the process method recommended by the "Technical Specifications for Slaughter and Meat Processing Wastewater Treatment Engineering" HJ20042010, most of these wastewater treatment needs can be met, but for enterprises with diverse products and cyclical production changes, the system impact is relatively large. The water quality is high in oil and salt, and the PH product fluctuates greatly, and TN and TP also fluctuate, causing troubles to operators and enterprises. Summary of the invention

[0003] The purpose of the present invention is to solve the above-mentioned problems. The present application proposes a system and method for treating food oily wastewater, which is suitable for production wastewater and domestic sewage. The set drum screen machine, horizontal flow oil separator, accident regulating tank, dissolved air flotation device, etc. enhance the front-end pretreatment, minimize the decomposition of pollutants and the entry of oil into the system, reduce investment, and adopt ABR process to facilitate personnel management. The improved multi-stage AO biochemical pool effectively realizes enhanced denitrification, thereby ensuring the phosphorus release and removal effect, and ensuring stable operation.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a treatment system for food oily wastewater, comprising production wastewater and domestic sewage, wherein the production wastewater is connected to a rotary drum screen machine via a pipeline, the outlet of the rotary drum screen machine is connected to a water collection and lifting tank, the water collection and lifting tank is connected to a horizontal flow oil separator through a water pump, the water outlet end of the horizontal flow oil separator is connected to an accident regulating tank, the water outlet end of the accident regulating tank is connected to a dissolved air flotation device through a water pump, the dissolved air flotation device is connected to a slag tank and an ABR anaerobic tank respectively, the ABR anaerobic tank is connected to a primary anoxic tank in a primary AO tank, the primary anoxic tank is connected to a primary aerobic tank, the water outlet end of the primary aerobic tank is connected to a secondary anoxic tank of a secondary AO tank, the secondary anoxic tank is connected to a secondary aerobic tank, the water outlet end of the secondary aerobic tank is connected to a secondary sedimentation tank, and the secondary sedimentation tank is connected to a flocculation sedimentation tank; The domestic sewage is connected to a three-compartment septic tank via a pipeline. An artificial grid is provided at the outlet of the three-compartment septic tank and connected to a water collection and lifting tank, and enters the treatment system together with the production wastewater.

[0005] Furthermore, the rotary drum screen machine, the horizontal flow oil separator and the dissolved air flotation device are also connected to the slag pool respectively.

[0006] Furthermore: demulsifier and coagulant for adjusting pH are added into the dissolved air flotation device.

[0007] Furthermore: the outlet end of the slag pool is connected to a sludge disposal unit for centralized removal of the sludge.

[0008] Furthermore: the flocculation sedimentation tank, the secondary sedimentation tank, and the ABR anaerobic tank are also connected to the sludge tank through water pumps respectively, and the sludge tank is connected to the sludge disposal unit.

[0009] Furthermore: the secondary aerobic tank is connected to the primary anoxic tank to form a nitrification liquid return system; the secondary sedimentation tank is connected to the rear end of the ABR anaerobic tank to form a sludge return system.

[0010] Preferred: A method for a food oily wastewater treatment system, comprising the following steps: S1. Collect the production wastewater and transport it to the rotary drum screen machine through pipelines to shorten the residence time of the residue in the water, and then send the wastewater to the horizontal flow grease trap; S2. The horizontal flow oil separator can achieve sedimentation at the bottom of the tank and oil removal on the surface of the tank. The sediment at the bottom of the tank is discharged into the slag tank, and the sewage is discharged into the accident regulating tank; S3. The outlet pipe of the accident regulating tank is connected to the dissolved air flotation device, and demulsifier and coagulant are added to enhance the oil removal and pretreatment effect at the front end. The treated water is discharged to the ABR anaerobic tank, and the residue is discharged to the slag tank; S4. The ABR anaerobic tank is equipped with an internal reflow system. The water treated in the ABR anaerobic tank is discharged into the AO tank, and the sludge is discharged into the sludge tank. The AO tank is equipped with two levels. The secondary aerobic tank is connected to the primary anoxic tank to form a nitrification liquid reflow system. The nitrification liquid reflow ratio is controlled at 200-400%, ensuring the denitrification demand. S5. After denitrification in the secondary aerobic tank, the wastewater is discharged into the secondary sedimentation tank, which is connected to the rear end of the ABR for sludge return. The sludge return ratio is controlled at 50-100%, which can reduce the impact of nitrate and dissolved oxygen on the ABR anaerobic tank. S6. The sewage after treatment in the secondary sedimentation tank is discharged into the flocculation sedimentation tank, the sludge settles at the bottom, the supernatant is discharged after reaching the standard through the pasteurization metering tank, and the sludge is discharged into the sludge tank through the water pump; S7. Transport the sludge in the sludge pool to the sludge treatment device for centralized removal; S8. The domestic sewage is discharged into a three-compartment septic tank through a pipeline. The outlet of the septic tank is connected to a water collection and extraction tank, and flows together with the production wastewater into a horizontal flow grease trap for subsequent treatment.

[0011] Compared with the prior art, the present invention has the following beneficial effects: The present invention arranges a drum screen machine, a water collection and lifting tank, a horizontal flow oil separator, an emergency regulating tank, a dissolved air flotation device and other pretreatment units with shorter processes and more targetedness at the front end of the treatment system, which reduces the residence time and decomposition chance of sludge or residue in the sewage, thereby indirectly reducing the investment in subsequent biochemical units and alleviating the treatment pressure of subsequent units.

[0012] The biochemical treatment unit uses a more inclusive ABR anaerobic tank, which reduces the company's operation and maintenance pressure. At the same time, a multi-stage AO tank is set up, which is more suitable for the high TN treatment brought about by meat food processing and is more stable.

[0013] The sludge treatment device and the dissolved air flotation device for adding medicine are centrally arranged to facilitate operation management and environmental sanitation control; the system of the present invention is more convenient to manage as a whole, more stable in operation, saves investment, and has guaranteed water output. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only for more clearly illustrating the embodiments of the present invention or the technical solutions in the prior art. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 It is a framework principle diagram of the overall structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0016] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments. However, the embodiments are only intended to illustrate the present invention and not to limit the present invention.

[0017] like Figure 1 A treatment system for food oily wastewater shown includes collection pipes for production wastewater and domestic sewage, the production wastewater is connected to a rotary drum screen machine via a pipe, the outlet of the rotary drum screen machine is connected to a water collection and lifting tank, the domestic sewage is connected to a three-compartment septic tank via a pipe, the outlet end of the three-compartment septic tank is provided with an artificial screen connected to the water collection and lifting tank, and enters the treatment system together with the production wastewater, the water collection and lifting tank is connected to a horizontal flow oil separator tank that is more suitable for the drainage characteristics of the enterprise, the outlet water of the horizontal flow oil separator tank is connected to an accident regulating tank, and then the outlet water enters the biochemical unit after being treated by a dissolved air flotation device and dosing simultaneously; The outlet of the dissolved air flotation device is connected to an ABR anaerobic tank with a higher fault tolerance rate. The sludge in the ABR anaerobic tank is discharged into the sludge tank through a water pump. The outlet of the ABR anaerobic tank is connected to a multi-stage AO tank to improve the denitrification efficiency. The first-level AO tank includes a first-level anoxic tank and a first-level aerobic tank. The second-level AO tank includes a second-level anoxic tank and a second-level aerobic tank. The second-level aerobic tank is connected to the first-level anoxic tank to form a nitrification liquid reflux state to ensure the denitrification demand. The nitrification liquid reflux ratio is controlled at 200~ 400%, the outlet end of the AO tank is connected to the secondary sedimentation tank, the secondary sedimentation tank is connected to the rear end of the ABR to form a sludge return system, the sludge return ratio is controlled at 50-100%, part of the sludge in the secondary sedimentation tank is returned to the ABR anaerobic tank through a water pump, and part of it is discharged into the sludge tank. The secondary sedimentation tank is connected to the flocculation sedimentation tank, and the supernatant of the flocculation sedimentation tank is discharged after meeting the standards, and the precipitated sludge is discharged into the sludge tank through a water pump. After the sludge tank is connected to the sludge treatment device, the sludge treatment device centrally removes the sludge.

[0018] The rotary drum screen machine, the horizontal flow oil separator, and the dissolved air flotation device are also connected to the slag pool and discharge the sludge in the slag pool into the slag pool. After the slag pool is connected to the sludge treatment device, the sludge treatment device centrally removes the sludge.

[0019] Preferably: the first anoxic tank and the second anoxic tank are each provided with a stirring device, and the first aerobic tank and the second aerobic tank are each provided with an aeration device for increasing dissolved oxygen.

[0020] Preferably: the system is also provided with an online dissolved oxygen monitoring device for monitoring the dissolved oxygen content in the ABR anaerobic tank, the first-level anoxic tank, the second-level anoxic tank, the first-level aerobic tank, and the second-level aerobic tank. The dissolved oxygen in the ABR anaerobic tank during operation is controlled to be less than 0.2 mg / L, and the pH value is controlled at 6.5-7; the dissolved oxygen in the first-level anoxic tank and the second-level anoxic tank is controlled to be 0.2-0.5 mg / L, and the pH is controlled at 7.5; the dissolved oxygen in the first-level aerobic tank and the second-level aerobic tank is controlled to be 3±1 mg / L, and the pH is controlled at 7.

[0021] Preferably: the system is also equipped with a dosing device, and the added carbon source can be industrial white sugar or waste white sugar in the production process; sodium carbonate is preferably used for pH adjustment, and alkalinity is supplemented while adjusting the acidity and alkali; the aeration fan adopts a variable frequency configuration; the nitrification liquid reflux pump adopts variable frequency control; and the whole adopts PLC automatic control management.

[0022] A method for a food oily wastewater treatment system, comprising the following steps: S1. After the production wastewater is collected and discharged to the drum screen machine through pipelines, the residence time of the residue in the water is reduced, thereby avoiding the decomposition of particulate matter and the increase of pollution load. After that, the wastewater flows into the water collection and lifting pool; S2. Wastewater in the water collection and lifting pool flows to the horizontal flow oil separator through a water pump. Compared with the traditional sand settling tank plus a small oil separator, the horizontal flow oil separator is more suitable for enterprise drainage, and can achieve sand settling at the bottom of the pool and oil removal on the pool surface. At the same time, a mechanical oil scraper can be used to greatly improve the operation efficiency and reduce personnel costs; the sediment is discharged into the slag pool, and the sewage is discharged into the accident regulating pool. The accident regulating pool can effectively cope with the impact of periodic production drainage. At the same time, the accident regulating pool reserves accident drainage pool capacity, reducing unnecessary civil engineering and water pump investment, and is more practical; S3. The outlet pipe of the accident regulating tank is connected to the dissolved air flotation device. Demulsifiers and coagulants are added to enhance the oil removal and pretreatment effect at the front end, and the COD removal is about 70%, which directly reduces the subsequent unit tank capacity and investment. The outlet end is changed to a water collection tank, which can not only meet the requirements of flotation inspection and repair water, but also can be used for acid-base adjustment; the water treated by the dissolved air flotation device is discharged to the ABR anaerobic tank, and the residue is discharged to the slag tank; S4. The ABR anaerobic tank is equipped with an internal reflow system. The water treated in the ABR anaerobic tank is discharged into the AO tank, and the sludge is discharged into the sludge tank. The AO tank is equipped with two levels. The secondary aerobic tank is connected to the primary anoxic tank to form a nitrification liquid reflow system. The nitrification liquid reflow ratio is controlled at 200-400%, ensuring the denitrification demand. S5. After denitrification in the secondary aerobic tank, the wastewater is discharged into the secondary sedimentation tank, which is connected to the rear end of the ABR for sludge return. The sludge return ratio is controlled at 50-100%, which can reduce the impact of nitrate and dissolved oxygen on the ABR anaerobic tank. S6. The sewage after treatment in the secondary sedimentation tank is discharged into the flocculation sedimentation tank, the sludge settles at the bottom, the supernatant is discharged after reaching the standard through the pasteurization metering tank, and the sludge is discharged into the sludge tank through the water pump; S7. Transport the sludge in the sludge pool to the sludge treatment device for centralized removal; S8. The domestic sewage is discharged into a three-compartment septic tank through a pipeline. The outlet of the septic tank is connected to a water collection and extraction tank, and flows together with the production wastewater into a horizontal flow grease trap for subsequent treatment. Example

[0023] This system was first used in the production wastewater treatment renovation projects of Juewei Food Factories across the country, such as Shanghai A Miao Food, Changsha Arei Food, Guizhou A Le Food, Fuzhou A Sheng Food, etc. Their original processes mostly used small grease traps, and the oil-water separation effect was poor. At the same time, in order to reduce the cost of external transportation, the factory accumulated oil residues and refluxed the filtrate, which eventually led to the fermentation and decomposition of meat and plant residues, doubling of TN, release of lignin from plants, and increased salt content in the water, which eventually led to the collapse of the system.

[0024] The present invention solves the root problem of the system in a more targeted manner on the basis of the existing process. A process unit with a shorter process and more targeted is selected from the pretreatment unit. The rotary drum screen machine, water collection and lifting tank, horizontal flow oil separator, accident regulating tank, and dissolved air flotation device directly reduce the residence time of pollution and the chance of decomposition. The horizontal flow oil separator reserves the capacity of the accident drainage tank, which reduces unnecessary civil engineering and water pump investment, thereby indirectly reducing the investment in subsequent biochemical units and alleviating the processing pressure of subsequent units. The biochemical treatment unit selects a more inclusive process, namely the ABR anaerobic tank, which reduces the pressure of enterprise operation and maintenance. At the same time, the multi-stage AO is more suitable for the high TN treatment brought by meat food processing, and is therefore more stable; management is more convenient, operation is more stable, investment is more economical, and water output is guaranteed.

[0025] The contents not described in detail in the present invention are all prior art.

[0026] The above description is only a preferred embodiment of the present invention, and is not limited to the description in the specification and implementation. Therefore, any equivalent changes or modifications made according to the structure, features and principles described in the scope of the present invention should be included in the scope of the present invention.

Claims

1. A system for treating oily food wastewater, including production wastewater and domestic sewage, characterized in that: The production wastewater is connected to the rotary drum screen machine through a pipeline, the outlet of the rotary drum screen machine is connected to the water collection and lifting tank, the water collection and lifting tank is connected to the horizontal flow oil separator through a water pump, the water outlet end of the horizontal flow oil separator is connected to the accident regulating tank, the water outlet end of the accident regulating tank is connected to the dissolved air flotation device through a water pump, the dissolved air flotation device is connected to the slag tank and the ABR anaerobic tank respectively, the ABR anaerobic tank is connected to the primary anoxic tank in the primary AO tank, the primary anoxic tank is connected to the primary aerobic tank, the water outlet end of the primary aerobic tank is connected to the secondary anoxic tank of the secondary AO tank, the secondary anoxic tank is connected to the secondary aerobic tank, the water outlet end of the secondary aerobic tank is connected to the secondary sedimentation tank, and the secondary sedimentation tank is connected to the flocculation sedimentation tank; The domestic sewage is connected to a three-compartment septic tank via a pipeline. An artificial grid is provided at the outlet of the three-compartment septic tank and connected to a water collection and lifting tank, and enters the treatment system together with the production wastewater.

2. A system for treating food oily wastewater according to claim 1, characterized in that: The rotary drum screen machine, the horizontal flow oil separator and the dissolved air flotation device are also connected to the slag pool respectively.

3. A system for treating food oily wastewater according to claim 1, characterized in that: Demulsifier and coagulant for adjusting pH are added into the dissolved air flotation device.

4. A system for treating food oily wastewater according to claim 1, characterized in that: The outlet end of the slag pool is connected to a sludge disposal unit for centralized removal of sludge.

5. The system for treating food oily wastewater according to claim 1, characterized in that: The flocculation sedimentation tank, the secondary sedimentation tank, and the ABR anaerobic tank are also connected to the sludge tank through water pumps, and the sludge tank is connected to the sludge disposal unit.

6. A system for treating food oily wastewater according to claim 1, characterized in that: The secondary aerobic tank is connected to the primary anoxic tank to form a nitrification liquid return system; the secondary sedimentation tank is connected to the rear end of the ABR anaerobic tank to form a sludge return system.

7. The method for treating food oily wastewater according to claim 1, characterized in that: The following steps are involved: S1. Collect the production wastewater and transport it to the drum screen machine through pipelines to shorten the residence time of the residue in the water. Then the wastewater flows into the water collection and lifting pool; S2. Wastewater in the water collection and lifting tank flows to the horizontal flow oil separator through a water pump, the sediment settles to the bottom and is discharged into the slag tank, and the sewage is discharged to the accident regulating tank; S3. The outlet pipe of the accident regulating tank is connected to the dissolved air flotation device, and demulsifier and coagulant are added to enhance the oil removal and pretreatment effect at the front end. The treated water is discharged to the ABR anaerobic tank, and the residue is discharged to the slag tank; S4. The ABR anaerobic tank is equipped with an internal reflow system. The water treated in the ABR anaerobic tank is discharged into the AO tank, and the sludge is discharged into the sludge tank. The AO tank is equipped with two levels. The secondary aerobic tank is connected to the primary anoxic tank to form a nitrification liquid reflow system. The nitrification liquid reflow ratio is controlled at 200-400%, ensuring the denitrification demand. S5. After denitrification in the secondary aerobic tank, the wastewater is discharged into the secondary sedimentation tank, which is connected to the rear end of the ABR for sludge return. The sludge return ratio is controlled at 50-100%, which can reduce the impact of nitrate and dissolved oxygen on the ABR anaerobic tank. S6. The sewage after treatment in the secondary sedimentation tank is discharged into the flocculation sedimentation tank, the sludge settles at the bottom, the supernatant is discharged after reaching the standard through the pasteurization metering tank, and the sludge is discharged into the sludge tank through the water pump; S7. Transport the sludge in the sludge pool to the sludge treatment device for centralized removal; S8. The domestic sewage is discharged into a three-compartment septic tank through a pipeline. The outlet of the septic tank is connected to a water collection and extraction tank, and flows together with the production wastewater into a horizontal flow grease trap for subsequent treatment.

Images