WO2003042110A1

WO2003042110A1 - Method of reusing food factory process water

Info

Publication number: WO2003042110A1
Application number: PCT/JP2002/010489
Authority: WO
Inventors: Masahiro Kawabata; Akifumi Obu
Original assignee: Organo Corporation
Priority date: 2001-11-14
Filing date: 2002-10-09
Publication date: 2003-05-22
Also published as: JP2005137949A

Abstract

In a food-related manufacturing factory, of the discharge process water discharged from the manufacturing process, the low-polluted discharge process water is collected. The collected discharge process water is sterilized by film-treatment or disinfection, and the sterilized water is reused as process water. The discharge process water in a food-related factory can be safely collected and reused, to reduce the process water consumption.

Description

Specification

Food factory process water reuse method

[Technical field]

The present invention relates to a method for reusing discharge process water discharged from a manufacturing process of a food-related factory.

[Background technology]

Conventionally, in food-related factories, a large amount of process water has been used in the washing process of raw materials such as vegetables and the manufacturing process such as the washing bottle process, but the discharged process water has not been reused. In other words, conventionally, the process water used in the manufacturing process of food-related factories was all tap water (巿 water), industrial water, or water with some treatment. This is because process water used once in the manufacturing process is considered to be wastewater, and recycling this wastewater back to the manufacturing process was not good for sanitation, even though there was no technical problem. is there.

Therefore, as shown in Fig. 3, the discharge water from the manufacturing process in conventional food-related factories is generally discharged to sewage or drainage treatment and discharged to rivers and other rivers.

FIG. 3 is a flowchart showing an example of a bottle washing process in a beverage manufacturing factory. As shown in Fig. 3, in the bottle washing process, tap water 31 was used as the process water, and the first pre-cleaning process 32, the second pre-cleaning process 33, the warm water cleaning process 34, and the finish cleaning process 35 were performed. It becomes. The wastewater 36 to 39 discharged from each washing process 32 to 35 is discharged to sewage 40. In recent years, the demand for water has become tighter due to the increase in water usage in each industry and water consumption caused by climate change, and the demands of local governments and others for factories and others to reduce water usage have increased. In addition, water charges and sewerage charges when draining wastewater from factories are increasing, and increasing costs at factories is becoming a problem.

[Disclosure of the Invention]

The present invention is intended to safely collect and reuse discharged process water in food-related factories, The aim is to reduce the amount of used.

The present inventors have conducted intensive studies, separated the water system discharged from the manufacturing process water, collected the water while determining its origin, that is, before mixing with the discharged water from other systems, and collecting the water. However, the present inventors have found that the above-mentioned problems can be solved by selecting system water containing as little impurities as possible as the water to be recovered and performing the recovery treatment, and have completed the present invention.

First, in the present invention, in a food-related manufacturing plant, low-contamination discharge process water of discharge process water discharged from a manufacturing process is collected and sterilized, and the sterilized water is reused as process water. It is characterized by doing.

Further, it is preferable that the low-contamination discharge process water is a discharge process water of TOC1Omg / 1 or less.

Further, it is preferable that the sterilization treatment is a membrane treatment.

Further, it is preferable that the sterilization treatment is a membrane treatment and a sterilization treatment. Further, it is preferable that the sterilization treatment is an oxidizing agent injection method.

Further, it is preferable that the film treatment is an MF treatment.

[Brief description of drawings]

FIG. 1 is a flowchart showing one embodiment of the method of the present invention.

FIG. 2 is a flowchart showing one embodiment of the sterilization process of the method of the present invention.

Figure 3 is a flow chart of the process water used in a conventional food-related factory.

[Best Mode for Carrying Out the Invention]

The production process in a food factory, which is the object of the present invention, is not particularly limited as long as it is a production process using process water.For example, a container production process in a beverage production plant, a vegetable production process in a food production plant, etc. Examples include the washing process of raw materials such as fruits, and the washing process of equipment such as piping and blending tanks.

The present invention is characterized by recovering relatively low-contamination water from the discharge process water discharged from the manufacturing process of a food factory, and reusing it in another process. Low-contamination water is used as the discharge process water for yield collection. Is less than 10 mg / l, preferably 5 mg / l or less. In addition, discharge process water with T〇C exceeding 1 O mg / l is not preferable because microorganisms can easily propagate. The sterilization treatment may be performed to such an extent that it can be used as process water in a process that does not require much cleanliness (a process other than the finish washing process). For example, the sterilization treatment may be performed at a cleanliness level of tap water.

The collected low-contamination discharge process water may be sterilized by a known method in food production. The sterilization treatment may be performed by, for example, a combination of a membrane treatment, a membrane treatment, and a sterilization treatment.

The membrane treatment in the present invention is not particularly limited as long as it is an apertured membrane capable of removing bacteria. For example, MF (microfiltration) membrane treatment, UF (ultrafiltration) membrane treatment or R 0 (reverse osmosis) And the like.

Of these membranes, the MF membrane has the largest aperture but has a high water flow rate, so the equipment can be reduced in size, so that the processing cost can be reduced.

The sterilization treatment in the present invention is not particularly limited, and examples thereof include a UV (ultraviolet) sterilization method, a hot water sterilization method, and an oxidizing agent sterilizing method using an oxidizing agent. As the oxidizing agent in the oxidizing sterilization method, for example, sodium hypochlorite, ozone, hydrogen peroxide and the like can be mentioned.

Of these sterilizing methods, the oxidizing agent sterilizing method using an oxidizing agent is preferable from the viewpoint of overall health and safety because the effect is maintained as long as the oxidizing agent remains.

By combining membrane treatment and sterilization treatment, the safety of treated water can be maintained by combining sterilization treatment even if bacteria pass through due to trouble in membrane treatment.

One embodiment of the present invention is shown in the flowchart of FIG.

As shown in Fig. 1, in the finish washing step (bottle washing step) 5, the bottle to be washed is washed using water 1 as the process water. The wastewater 10 from this washing step 5 is treated in the wastewater recovery equipment 11, and the treated water, collected water 12, is sent to the first preliminary washing step 2, the second preliminary washing step 3, and the hot water washing step 4. Supplied and used here as process water. Then, the drainage water 6, 7, 8 from the first pre-cleaning step 2, the second pre-cleaning step 3, and the hot water cleaning step 4 is discharged 9 into the sewage. Although illustration is omitted, in the initial stage of the first pre-cleaning step 2, the second pre-cleaning step 3, and the hot water cleaning step 4, a cleaning operation is performed using hot water.

In the finish washing step 5, water 1 is used. The wastewater 10 discharged from the finish cleaning process is low-pollutant wastewater. The low-contamination wastewater 10 flows into the wastewater recovery facility 11 and is sterilized by membrane treatment or membrane treatment + sterilization treatment. The recovered water sterilized by the wastewater recovery equipment 1 1 is reused as process water for the first pre-cleaning step 2, the second pre-cleaning step 3 and the hot water cleaning step 4, which do not require much cleanliness. The wastewater 6 to 8 discharged from the first pre-cleaning step 2, the second pre-cleaning step 3 and the hot water cleaning step 4 are discharged into sewage 9.

One embodiment of the wastewater recovery equipment 11 for sterilizing the water in the discharge process is shown in the flow diagram of FIG.

The discharge process water to be recovered is first stored in the recovered raw water tank 13. The recovered raw water in the recovered raw water tank 13 is supplied to the heat exchanger 16 by the recovered raw water pump 14, and the recovered raw water is supplied to the recovered raw water from the sodium hypochlorite storage tank 15 at the previous stage. One dose is injected. Therefore, the recovered raw water into which the sodium hypochlorite has been injected is supplied to the heat exchanger 16. The recovered raw water whose temperature has been adjusted to the heat exchanger 16 is sent to the MF membrane module 18.

The water in the constant temperature water tank 17 is circulated to the heat exchanger 16 for adjusting the temperature of the recovered raw water. In an unsteady state, heated steam can be blown into this circulation line to sterilize the system with hot water.

Here, sodium hypochlorite functions as a disinfectant, and disinfects the recovered raw water. The treated water filtered by the MF membrane module 18 is temporarily stored in the treated water tank 19, and the treated water in the treated water tank 19 is manufactured via the treated water pump 20. Sent to the process and reused.

The example shown in Fig. 2 is an example in which the injection point of sodium hypochlorite is placed first (before the heat exchanger 16). It is possible to inject the fungicide at a later stage, but the advantage of placing the injection point first is that the entire recovery system can be sterilized. On the other hand, the disadvantages are that corrosion-resistant materials must be used for the entire recovery system, and a large amount of injection is required in order to maintain the sterilization effect until the final point, compared to the latter injection. Is necessary. The purpose of the heat exchanger 16 is to regulate the temperature of the drainage process water and to perform hot water sterilization that may be performed irregularly.

In the flow of FIG. 2, an external pressure type hollow fiber type is used as the MF membrane module 18. For this reason, when performing regular cleaning, stop the inflow of raw water and backwash by introducing high-pressure air into the hollow fibers through the air storage tank 22 with the compressor 21 to remove the water from the membrane surface. The trapped particulate components are removed and taken out of the system as washing wastewater. In addition, there are various types of MF membranes such as a flat membrane type and a tubular type, but basically any type of membrane may be used to achieve the object of the present invention.

"Concrete example"

At the food manufacturing plant, as shown in the flow chart in Fig. 1, the discharge water in the finish cleaning process was sterilized and reused in the first pre-cleaning process, the second pre-cleaning process, and the hot water cleaning process. As the treatment, a wastewater recovery facility 11 as shown in Fig. 2 was used, and an example in which sodium hypochlorite was added to perform MF membrane treatment, and an example in which only MF membrane treatment was performed. The amount of sodium hypochlorite added was 5 mg / l. The MF film used had a pore size of 0.2 μm.

The quality of the recovered raw water and the treated water after sterilization was analyzed, and the results are shown in Table 1. "table 1"

Use of MF membrane to obtain very clear treated water It can be seen that the treated water can be reused as process water.

In addition, in the results shown in Table 1, the case of only the MF membrane treatment shows a viable cell count of 2.3 cells / ml, but in principle, the number of MF membranes having a pore size of 0.2 im is It is unlikely that m live bacteria will pass through. This is thought to be due to bacteria contaminated from outside during sampling and analysis operations.

As described above, according to the present invention, it has become possible to safely collect and reuse discharged process water in a food-related factory, thereby reducing the amount of process water used.

Claims

The scope of the claims

1. In a food-related manufacturing plant,

A method for recycling water in a food factory process, comprising collecting and sterilizing low-contamination discharge process water from discharge process water discharged from a manufacturing process, and reusing the sterilized water as process water.

2. The method according to claim 1, wherein

A method for reusing water in a food factory process, wherein the low-contamination discharge process water is a discharge process water of TOC1Omg / 1 or less.

3. The method according to claim 1, wherein

The method for reusing water in a food factory process, wherein the sterilization treatment is a membrane treatment.

4. The method of claim 1, wherein:

A water recycling method for a food factory process, wherein the sterilization treatment is a membrane treatment and a sterilization treatment.

5. The method of claim 4, wherein:

A method for reusing water in a food factory process, wherein the sterilization treatment is an oxidizing agent injection method.

6. The method of claim 4, wherein:

A method for reusing water in a food factory process, wherein the membrane treatment is MF membrane treatment, UF membrane treatment or RO membrane treatment.

7. The method of claim 1, wherein:

The low-contamination discharge process water is waste water from a finish cleaning process of performing final cleaning of the bottle by using water in the bottle washing process, and the sterilized water is a waste water of the bottle performed prior to the final cleaning. A food factory process characterized by being used in a pre-cleaning process.