CN114426375A

Movatterモバイル変換

Info

Publication number: CN114426375A
Application number: CN202111573042.0A
Authority: CN
Inventors: 刘坚; 刘守龙; 丁黎玲; 何晶
Original assignee: Shenzhen Yuepeng Environmental Protection Technology Co Ltd
Current assignee: Shenzhen Yuepeng Environmental Protection Technology Co Ltd
Priority date: 2021-12-21
Filing date: 2021-12-21
Publication date: 2022-05-03

Abstract

The invention discloses a food production wastewater treatment method, which comprises the steps of firstly collecting wastewater, and then removing solid particles and oil substances in the wastewater through pretreatment so as to reduce the treatment difficulty of subsequent wastewater; the wastewater enters the comprehensive regulating tank for homogeneous and uniform regulation after physicochemical pretreatment, and then is subjected to subsequent treatment by adopting a process of 'two-stage anaerobic treatment, contact oxidation and flocculation precipitation', and the method has the following advantages: the process system can better deal with the characteristics of large water quality and large water quantity fluctuation of the food production wastewater, and solves the problem that the common wastewater treatment process is not influenced by impact according to the discharge rule and the production cycle characteristics of the production wastewater. The system does not need to add medicine and treat sludge, the process has strong pertinence, simple operation, low operation cost about 90 percent compared with the traditional physicochemical process, greatly reduced alkali liquor cost, no sludge, small occupied area and convenient management.

Description

Food production wastewater treatment method

Technical Field

The invention relates to the technical field of wastewater treatment, in particular to a food production wastewater treatment method.

Background

1. In some food production processes, peeling, cleaning, cooking, stir-frying and other processes of raw materials are involved, and in the production processes, some production wastewater is generated, wherein the cleaning and cooking processes are main processes for discharging wastewater. The wastewater mainly contains high organic matters, oily wastewater and the like discharged in cleaning and cooking processes.

2. At present, the treatment method of food production wastewater mainly comprises a physical method, a chemical method, a biological method and the like, and most of the methods are combined for use. Because the food processing production process, especially some bean product processing products are generally solid products after processing, the liquid part generated in the processing process is generally discharged as the initial wastewater in the cleaning and cooking processes, so that the organic matters and protein substances in the wastewater are very high, and in addition, some food additives are added in the subsequent forming process for frying, coloring and the like, the production wastewater generated in the process of cleaning equipment contains a large amount of substances such as oil and the like, so that the food wastewater is generally high in oil content, high in COD (chemical oxygen demand) and high in suspended matters, therefore, a large amount of medicaments are required to be added in the process of treating the wastewater, meanwhile, as COD in the wastewater is higher, the amount of sludge generated in the subsequent biochemical reaction process is larger, the treatment cost is high, the investment cost is high, the occupied area is wide, and the like, and the effluent is difficult to meet the discharge standard.

3. The biodegradability of food wastewater is generally good, and the COD concentration is high, so a large amount of biochemical sludge is generated in the subsequent biochemical treatment process, on one hand, mechanical dewatering equipment is required to be added for solid-liquid separation of the biochemical sludge, on the other hand, the dewatered mud cake is required to be subjected to subsequent treatment, the equipment investment cost of engineering is increased, and on the other hand, the operation cost of the whole treatment system is also increased.

The invention patent with application number 201310514965.8 discloses a method for treating high-fat food processing wastewater. The method mainly comprises the following processes: the grid → the water collecting tank → the ABR reactor → the UBF reaction tank → the combined air flotation tank → the A/O reaction tank → the sedimentation tank → the coagulation reaction tank → the filter cloth filter tank → the contact tank → the discharge; sedimentation tank sludge → sludge concentration tank → mechanical dehydration. The treatment process mainly has the following problems: firstly, a combined air-flotation oil removal device is arranged at the rear end of an ABR and UBF reaction system, the treated wastewater belongs to high-grease food wastewater, and oil substances enter an ABR reactor and a UBF reactor and are easy to scale in the system, so that the system runs fast; secondly, a large amount of chemical agents are required to be added in the wastewater treatment process, so that the labor cost and the agent cost in the wastewater treatment process are increased, the operation process is long, and the treatment cost is high; therefore, the process is suitable for cleaning wastewater in the production process, and the requirement of standard discharge of effluent when the system impact load is large is difficult to meet.

The invention patent with application number CN201510649976.6 discloses a food industry sewage treatment system and a method, the method mainly adopts the method of pretreatment, biochemical treatment and filtration treatment to treat the waste water, and the main steps comprise: (1) the wastewater enters a water collecting tank to be collected and then enters a hydraulic screen through a lifting pump, and larger suspended particle solid matters in the wastewater are removed through the hydraulic screen; (2) introducing the pretreated effluent into a biochemical contact oxidation tank for aeration reaction; (3) precipitating and separating the effluent after the biochemical reaction; the treatment method can be used for treating a certain type of automobile production wastewater to a certain extent, but the treatment of all types of automobile production wastewater is difficult to realize, and an anaerobic system is lacked in the whole biochemical treatment system, so that organic matters in the wastewater are difficult to meet the requirement of standard discharge, and the drainage of the automobile industry is irregular, the water quality fluctuation is large, and the system impact load is easy to cause.

Disclosure of Invention

The invention aims to provide a food production wastewater treatment method to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a treatment method of food production wastewater, firstly, collecting the wastewater, and then removing solid particles and oil substances in the wastewater through pretreatment to reduce the treatment difficulty of subsequent wastewater; after the physicochemical pretreatment, the wastewater enters a comprehensive regulating tank for homogeneous and uniform regulation, and then the subsequent treatment is carried out on the wastewater by adopting a process of 'two-stage anaerobic treatment, contact oxidation and flocculation precipitation'.

A food production wastewater treatment process is characterized in that: the method comprises the following steps:

s1: food production wastewater is collected by a pipeline and then enters a wastewater treatment system for pretreatment; the pretreatment system comprises a deslagging system and an oil separation system, wherein the deslagging system adopts a fine grid, larger suspended matters in the wastewater are removed through the fine grid, then the wastewater enters a drum-type grid cylinder to further remove fine particles in the wastewater, effluent enters an oil separation tank, oil substances in the wastewater are removed through the oil separation tank, and the effluent enters an adjusting tank to be homogenized and uniformly adjusted;

s2: after the wastewater is homogenized and uniformly regulated, the wastewater is lifted to an anaerobic system through a lift pump, the anaerobic system adopts a two-stage ascending anaerobic sludge bed, COD in the wastewater is removed mainly through the action of anaerobic microorganisms through hydrolysis, acidification and methanation processes, and meanwhile, organic matters which are difficult to degrade are decomposed into organic matters which are easy to degrade, so that the biodegradability of the wastewater is further improved;

s3: after the wastewater is treated by a two-stage ascending anaerobic sludge bed, the effluent automatically flows into a contact oxidation tank.

S4: in a contact oxidation pond, aerobic microorganisms are attached to and grow on biological fillers under the aerobic aeration condition, organic matters in wastewater are further decomposed into water and carbon dioxide through metabolism by using domesticated aerobic bacteria, the aerobic bacteria propagate, part of the aerobic bacteria enter a sedimentation tank along with effluent to be discharged as residual sludge, part of the aerobic bacteria flow back to the front end of the contact oxidation pond, and supernatant liquid obtained after solid-liquid separation in the sedimentation tank enters an intermediate tank for further treatment;

s5: in the middle pond, squeeze into the charcoal sand filter with waste water through filtering the water pump, filter the less suspended particles thing in the waste water on the one hand, on the other hand further handles the pollutant in the waste water through adsorption. The filtered effluent enters a discharge channel and is discharged out after reaching the standard;

s6: sludge in the sedimentation tank is discharged into a front-end anaerobic treatment system through a pump, and is degraded and consumed through the anaerobic treatment system;

as a preferred embodiment of the present invention, in step S1, the wastewater is pretreated, the pretreatment includes deslagging and oil removal, wherein the deslagging section employs a fine grid and a drum grid to remove larger suspended solid particles and fine scum materials, respectively; in the oil removal section, an oil separation tank is adopted to remove oil and fat substances in the wastewater.

As a preferable scheme of the invention, in the step S1, the wastewater is pretreated, chemical agents do not need to be added in the pretreatment process, and a drug adding system does not need to be arranged in the whole treatment system.

As a preferable scheme of the invention, in the step S2, a two-stage UASB reaction system is adopted, the ascending flow velocity in the reaction system is controlled to be 0.8-1 m/S, the temperature of the system is controlled to be 30 ℃, the reflux ratio in the system is 2:1, the residence time of a first-stage UASB anaerobic system is 72 hours, the residence time of a second-stage UASB anaerobic system is 48 hours, and the water distribution form of the first-stage and second-stage anaerobic systems adopts a pulse type water distributor for water distribution.

In a preferred embodiment of the present invention, in step S3, the concentration of dissolved oxygen in the contact oxidation reaction tank is controlled to be 2 mg/L.

In a preferred embodiment of the present invention, in step S4, the contact oxidation reaction tank has a residence time of 6 hours.

In a preferred embodiment of the present invention, in step S5, the volume ratio of the activated carbon to the silica sand is 2:1, and the particle size is 5 to 10 mm.

In a preferred embodiment of the present invention, in step S6, a part of the excess sludge in the sedimentation tank is pumped into a primary UASB treatment system at the front end of the system by a sludge discharge pump, and the whole sludge system does not generate sludge and does not need to be provided with a sludge treatment system.

Compared with the prior art, the invention has the beneficial effects that:

1) the process system can better deal with the characteristics of large water quality and large water quantity fluctuation of the food production wastewater, and solves the problem that the common wastewater treatment process is not influenced by impact according to the discharge rule and the production cycle characteristics of the production wastewater.

2) The treatment process adopts a treatment form combining pretreatment and a biochemical method, wherein the pretreatment mainly removes solid suspended matters and oil substances in the wastewater, and then the wastewater enters a biochemical treatment system after being homogenized and uniformly regulated, so that each pollution factor is further reduced to reach the standard of discharge.

3) The biochemical system adopts a two-stage UASB + contact oxidation treatment process, and the treatment load is high; the BOD removal rate is high (90-95 percent); the operation is stable, the structure is simple, and the volume required by the high volume load rate (8-10 kgCOD/m3.d) is greatly reduced.

4) The external reflux system is additionally arranged, alkalinity can be supplemented by reflux water during the operation of the anaerobic reactor, and the cost of the alkali liquor can be greatly reduced.

5) And residual sludge generated by the sedimentation tank is discharged to an anaerobic treatment system of the system for treatment, and then internal consumption is carried out, so that no sludge is generated.

6) The floor area is small, and the management is convenient.

Drawings

FIG. 1 is a schematic view of a food production wastewater treatment process according to the present invention;

FIG. 2 is a flow chart of a food production wastewater treatment method according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and all other embodiments obtained by a person of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the protection scope of the present invention.

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Several embodiments of the invention are presented in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1-2, the present invention provides a technical solution: a treatment method of food production wastewater, firstly, collecting the wastewater, and then removing solid particles and oil substances in the wastewater through pretreatment to reduce the treatment difficulty of subsequent wastewater; after the physicochemical pretreatment, the wastewater enters a comprehensive regulating tank for homogeneous and uniform regulation, and then the subsequent treatment is carried out on the wastewater by adopting a process of 'two-stage anaerobic treatment, contact oxidation and flocculation precipitation'.

In an embodiment, referring to fig. 2, a process for treating wastewater from food production is characterized in that: the method comprises the following steps:

s5: in the middle pond, squeeze into the charcoal sand filter with waste water through filtering the water pump, filter the less suspended particles thing in the waste water on the one hand, on the other hand further handles the pollutant in the waste water through adsorption. The filtered effluent enters a discharge channel and is discharged after reaching the standard;

in step S1, the wastewater is pretreated, the pretreatment comprises slag removal and oil removal processes, wherein a fine grid and a rotary drum grid are adopted in the slag removal process to remove larger suspended solid particles and fine scum substances respectively; in the oil removal section, an oil separation tank is adopted to remove oil and fat substances in the wastewater.

In the step S1, the wastewater is pretreated, chemical agents do not need to be added in the pretreatment process, and a medicine adding system does not need to be arranged in the whole treatment system.

In the step S2, a two-stage UASB reaction system is adopted, the ascending flow velocity in the reaction system is controlled to be 0.8-1 m/S, the temperature of the system is controlled to be 30 ℃, the reflux ratio in the system is 2:1, the residence time of a first-stage UASB anaerobic system is 72 hours, the residence time of a second-stage UASB anaerobic system is 48 hours, and water distribution of the first-stage and second-stage UASB anaerobic systems is carried out by adopting a pulse type water distributor.

In step S3, the concentration of dissolved oxygen in the contact oxidation reaction tank is controlled to be 2 mg/L.

In step S4, the residence time of the contact oxidation reaction tank is 6 h.

In step S5, the volume ratio of the activated carbon to the quartz sand is 2:1, and the particle size is 5-10 mm.

In step S6, part of the residual sludge in the sedimentation tank is pumped into a primary UASB treatment system at the front end of the system through a sludge discharge pump, and the whole sludge system does not generate sludge and does not need a sludge treatment system.

In the embodiment, as shown in fig. 1, food wastewater enters a water collecting well after being collected by a pipeline, a fine grid is arranged in the water collecting well, larger solid particles in the wastewater are treated by the fine grid, fine suspended matters in the wastewater are removed by effluent water treated by the fine grid through a drum type grid, the effluent water enters an oil separation tank, oil substances in the wastewater are removed by oil separation in the oil separation tank, the effluent water enters an adjusting tank for homogenizing and uniform adjustment, and the adjusted effluent water is lifted to a two-stage UASB system through a lifting pump for anaerobic treatment. After the wastewater enters a UASB system, COD in the wastewater is removed mainly through the action of anaerobic microorganisms through the processes of hydrolysis, acidification and methanation, and the effluent enters a contact oxidation tank; in the contact oxidation pond, under the aerobic condition of aeration, aerobic microorganisms are attached to and grow on biological fillers, organic matters in the wastewater are further decomposed into water and carbon dioxide through metabolism by using domesticated aerobic bacteria, the aerobic bacteria propagate, part of the aerobic bacteria enter a sedimentation tank along with effluent to be discharged as residual sludge, a small part of the aerobic bacteria flows back to the front end of the contact oxidation pond, supernatant liquid obtained after solid-liquid separation of the sedimentation tank enters an intermediate tank to be further treated, the wastewater is pumped into a carbon sand filter through a filter water pump after being temporarily stored in the intermediate tank, on one hand, small suspended particulate matters in the wastewater are filtered, and on the other hand, pollutants in the wastewater are further treated through adsorption. The filtered effluent enters a discharge channel to be discharged after reaching the standard.

And the sludge in the sedimentation tank is discharged into the primary anaerobic treatment system through a sludge discharge pump, and is degraded and consumed through the anaerobic treatment system.

Description of the principle:

1. principle of UASB reaction system (upflow anaerobic sludge blanket):

the UASB consists of a sludge reaction area, a gas-liquid-solid three-phase separator (including a sedimentation area) and a gas chamber. A large amount of anaerobic sludge is reserved in the bottom reaction zone, and sludge with good settling property and coagulation property forms a sludge layer at the lower part. The wastewater flows into the anaerobic sludge bed from the bottom of the anaerobic sludge bed to be mixed and contacted with sludge in the sludge layer, and microorganisms in the sludge decompose organic matters in the wastewater to convert the organic matters into methane. The biogas is continuously discharged in the form of micro bubbles, the micro bubbles are continuously combined in the ascending process to gradually form larger bubbles, sludge with thinner sludge concentration is formed at the upper part of a sludge bed due to the stirring of the biogas and rises together with water to enter a three-phase separator, when the biogas touches a reflecting plate at the lower part of the separator, the biogas is folded around the reflecting plate, then the biogas passes through a water layer to enter a gas chamber and is concentrated in the gas chamber and is guided out by a guide pipe, a solid-liquid mixed liquid enters a settling zone of the three-phase separator through reflection, the sludge in the sewage is flocculated, particles are gradually increased, and the sludge is settled under the action of gravity. The sludge deposited on the inclined wall slides back to the anaerobic reaction zone along the inclined wall, so that a large amount of sludge is accumulated in the reaction zone, treated effluent separated from the sludge overflows from the upper part of an overflow weir of the deposition zone, and then a sludge bed is discharged.

The anaerobic reaction process can be divided into four relatively independent and inseparable steps: hydrolysis stage, acidification stage, hydrogen production and acetic acid production stage and methane production stage.

The first group of microorganisms, the acidifying bacteria, performs the first two steps of the anaerobic digestion process, hydrolysis and acidification. They hydrolyze polymers such as proteins, fats and carbohydrates into small molecules that can enter the cell interior by extracellular enzymes, where they are oxidatively degraded to form carbon dioxide (CO2), hydrogen (H2) and the main product, Volatile Fatty Acids (VFA).

The second group of microorganisms, hydrogen-producing acetogenic bacteria, convert the above products into acetate, hydrogen and carbon dioxide during the acidification process.

The third group of microorganisms are methanogens, which convert acetate or hydrogen and carbon dioxide to methane.

Example 1, the food products such as cakes and the like are produced by a food company Limited in Tansha city, and mainly generate food production wastewater in the production process, wherein the wastewater contains COD, BOD5, SS and a small amount of oil-containing substances, and the amount of wastewater generated per day is 1000m 3/d. The water quality of various waste water is shown in the following table:

the food wastewater treatment adopts the process flows of pretreatment, UASB (upflow anaerobic sludge blanket), contact oxidation and charcoal sand filtration, after large solid particles in the wastewater are removed by a fine grid, the effluent enters a drum grid to further remove small suspended matters in the wastewater, then enters an oil separation tank, and enters an adjusting tank after oil substances in the wastewater are removed in the oil separation tank. And (4) the pretreated effluent enters an adjusting tank for homogenizing and uniform adjustment. The water outlet after adjustment is lifted to a two-stage UASB reactor, the UASB carries out water distribution through a pulse water distributor, wherein the reaction residence time of the first-stage UASB is 72h, the residence time of the second-stage UASB is 48h, the pH value is controlled between 6.8 and 7.3, the rising speed is controlled at 1m/s, and the internal circulation ratio is 2: 1. and (2) adopting a mechanical aeration oxidation mode in the contact oxidation tank, controlling the gas-water ratio to be 15-20: 1, controlling the dissolved oxygen to be about 2.0mg/L, and filtering the effluent carbon sand after reaction (V active carbon: V quartz sand is 2: 1). The effluent after the treatment of the system has COD cr of 85mg/L, BOD of 16mg/L, oils of 2mg/L, SS of 10mg/L and pH value of about 6.8, and reaches the first grade discharge standard in the Table 4 of Integrated wastewater discharge Standard (GB 8978-1996).

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A treatment method of food production wastewater is characterized by comprising the following steps: firstly, collecting waste water, and then removing solid particles and oil substances in the waste water through pretreatment so as to reduce the treatment difficulty of subsequent waste water; after the physicochemical pretreatment, the wastewater enters a comprehensive regulating tank for homogeneous and uniform regulation, and then the subsequent treatment is carried out on the wastewater by adopting a process of 'two-stage anaerobic treatment, contact oxidation and flocculation precipitation'.

2. A food production wastewater treatment process is characterized in that: the method comprises the following steps:

s1: food production wastewater is collected by a pipeline and enters a wastewater treatment system for pretreatment; the pretreatment system comprises a deslagging system and an oil separation system, wherein the deslagging system adopts a fine grid, larger suspended matters in the wastewater are removed through the fine grid, then the wastewater enters a drum-type grid cylinder to further remove fine particles in the wastewater, effluent enters an oil separation tank, oil substances in the wastewater are removed through the oil separation tank, and the effluent enters an adjusting tank to be homogenized and uniformly adjusted;

s6: and (4) discharging the sludge in the sedimentation tank into a front-end anaerobic treatment system through a pump, and performing degradation consumption through the anaerobic treatment system.

3. The wastewater treatment process of claim 2, wherein: in step S1, the wastewater is pretreated, the pretreatment comprises slag removal and oil removal processes, wherein a fine grid and a rotary drum grid are adopted in the slag removal process to remove larger suspended solid particles and fine scum substances respectively; in the oil removal section, an oil separation tank is adopted to remove oil and fat substances in the wastewater.

4. The wastewater treatment process of claim 2, wherein: in the step S1, the wastewater is pretreated, chemical agents do not need to be added in the pretreatment process, and a medicine adding system does not need to be arranged in the whole treatment system.

5. The food production wastewater treatment process according to claim 2, wherein: in the step S2, a two-stage UASB reaction system is adopted, the ascending flow velocity in the reaction system is controlled to be 0.8-1 m/S, the temperature of the system is controlled to be 30 ℃, the reflux ratio in the system is 2:1, the residence time of a first-stage UASB anaerobic system is 72 hours, the residence time of a second-stage UASB anaerobic system is 48 hours, and water distribution of the first-stage and second-stage UASB anaerobic systems is carried out by adopting a pulse type water distributor.

6. The food production wastewater treatment process according to claim 2, wherein: in step S3, the concentration of dissolved oxygen in the contact oxidation reaction tank is controlled to be 2 mg/L.

7. The food production wastewater treatment process according to claim 2, wherein: in step S4, the residence time of the contact oxidation reaction tank is 6 h.

8. The food production wastewater treatment process according to claim 2, wherein: in step S5, the volume ratio of the activated carbon to the quartz sand is 2:1, and the particle size is 5-10 mm.

9. The food production wastewater treatment process according to claim 2, wherein: in step S6, part of the residual sludge in the sedimentation tank is pumped into a primary UASB treatment system at the front end of the system through a sludge discharge pump, and the whole sludge system does not generate sludge and does not need a sludge treatment system.