JP5147930B2 - Waste milk processing apparatus and method - Google Patents

Description

  The present invention relates to a waste milk processing apparatus and method that performs waste sewage treatment in a milking facility together with disposal of waste milk.

In a milking facility (milking parlor), washing water from a milking machine (milk transport pipeline, milker, bulk tank) becomes discharged sewage.
In addition, washing water for excreta discharged from the milking platform is also discharged wastewater.
In addition to these waste sewage, there is a problem of disposal of waste milk. Waste milk is said to be difficult to clean because it is high fat and contains vaccines.
Patent Document 1 proposes a wastewater treatment agent mainly composed of oyster shells.
Patent Document 2 proposes a method for purifying parlor wastewater using a dried microbial cell to which lipid is attached, a metal compound composed of a water-soluble metal salt / metal oxide, and a polymer flocculant.

JP 2006-297301 A JP 2010-240582 A

With the full enforcement (November 2004) of the Livestock Excretion Act (Act on the Optimization of the Management of Livestock Excretion and Promotion of Utilization), the need for appropriate disposal of waste milk has increased.
An object of this invention is to provide the processing apparatus and method which process waste milk appropriately.

  The processing apparatus and method of the present invention have the following four main features. First, the upflow anaerobic sludge blanket (UASB) is incorporated. Second, a contact aeration tank that uses oyster shells as a contact material is provided. Third, a rocking floor aeration tank is provided that uses a string-like contact material as a contact material and aeration. Fourth, a contact aeration method using carbon fiber is adopted in the latter half of the treatment process.

  A waste milk processing apparatus according to the present invention is a waste milk processing apparatus for processing waste milk produced in a milking facility so as to reach a discharge standard, and is provided with a first sedimentation separation tank that inputs waste milk and performs precipitation separation processing. The precipitation separation tank is subjected to precipitation separation treatment in the first precipitation separation tank, and the treated water that has flowed out is added, and then the precipitation separation tank second tank that performs the precipitation separation treatment again, the precipitation separation tank second tank, and the precipitation separation tank first The sludge concentration storage tank first tank which concentrates sludge by the treatment of one tank, and sucks and removes the rising slum and the concentrated sludge with a slurry pump, the first sludge concentration storage tank, and the precipitation separation tank The UASB tank which processed the water which passed through the process of the 1st tank and the said precipitation separation tank 2nd tank using the upflow anaerobic sludge filter bed method and UASB (Upflow Anaerobic Sludge Blanket), and passed through the process of this UASB tank Anaerobic floor tank for anaerobic treatment of water And a second sludge concentration storage tank for concentrating excess sludge generated by the treatment with the anaerobic filter bed tank, and water after the treatment with the anaerobic filter bed tank, and aerated using oyster shell as a contact material Oyster shell contact aeration tank first tank and swing floor aeration tank first tank that uses a string-like contact material as a contact material for the water that has been treated by the oyster shell contact aeration tank first tank A carbon fiber aeration tank that performs contact aeration using carbon fiber on water that has undergone the treatment in the first aeration tank aeration tank, and water that has undergone the treatment in the carbon fiber aeration tank. An aeration screen for depositing sludge and advancing the supernatant; an aeration screen for feeding water transferred from the advection / precipitation tank together with other waste water in the milking facility; and the aeration screen A flow rate adjusting tank for adjusting the flow rate of water charged into The oyster shell contact aeration tank second tank for aeration by contacting the oyster shell with water through the volume adjustment tank, and the string-like contact material for the water processed by the second oyster shell contact aeration tank A second oscillating bed aeration tank that is used as a contact material and aerated while oscillating it; a settling tank that performs a precipitation separation process on the water that has been treated by the second oscillating bed aeration tank; A third sludge concentration storage tank for concentrating excess sludge generated in the settling tank, a disinfection tank for performing a treatment for killing pathogenic microorganisms on the supernatant separated in the settling tank, and the disinfection tank And a discharge tank for storing the water sterilized in (1), and processing the waste milk until the discharge standard is reached.

  A waste milk processing method according to the present invention is a waste milk processing method for processing waste milk generated in a milking facility so as to reach a discharge standard, and throws the waste milk into a first tank for precipitation separation so as to perform precipitation separation. A first precipitation separation step, a second precipitation separation step in which the precipitation separation process is performed in the first precipitation separation step, and the treated water that has flowed out is added and the precipitate separation process is performed again; the second precipitation separation step; A first sludge concentration and storage step for concentrating sludge by the treatment of one precipitation separation step and sucking and removing the floating slum and the concentrated sludge with a slurry pump, the first sludge concentration and storage step, and the first precipitation The UASB step of treating the water that has undergone the treatment of the separation step and the second precipitation separation step using an upflow anaerobic sludge filter bed method / UASB (Upflow Anaerobic Sludge Blanket) An anaerobic filter bed step that performs anaerobic treatment on the water that has undergone the process of the UASB step, a second sludge concentration storage step that concentrates excess sludge generated by the treatment in the anaerobic filter bed step, and the anaerobic filter bed The first oyster shell contact aeration step in which water treated through the step is introduced and aerated using oyster shell as a contact material, and the string-like contact with the water processed by the first oyster shell contact aeration step A swing floor aeration step that uses a material as a contact material and aeration, and a carbon fiber aeration step that applies contact aeration using carbon fiber to the water that has undergone the treatment by the first swing floor aeration step. In addition, the water subjected to the carbon fiber aeration step is allowed to precipitate sludge and advection / sedimentation step for advancing the supernatant, and the water advected from the advection / sedimentation step is subjected to milking. In addition to the other drainage in the above, the aeration type screen introduction step to be introduced, the flow rate adjustment step for adjusting the flow rate of the water introduced in the aeration type screen introduction step, and the water that has passed through the flow rate adjustment step, A second oyster shell contact aeration step that aerates in contact with the shell, and a second swing that aerates the water that has been treated by the second oyster shell contact aeration step using a string contact material as a contact material A bed aeration step, a precipitation step for subjecting the water subjected to the treatment by the second rocking bed aeration step to a precipitation separation process, and a third sludge concentration storage step for concentrating excess sludge generated in the precipitation step. A sterilization step for killing pathogenic microorganisms with respect to the supernatant separated in the precipitation step, and a discharge step for storing the water sterilized in the sterilization step. And a flop, which comprises treating until the waste milk effluent standard.

Since this invention is comprised as mentioned above, it has the following effect.
1 Since useful microorganisms are used, milk fat and nitrogen compounds are also degraded.
2 Since the microorganisms are limited according to the role of each water tank, the facility can be downsized.
3 Since it works efficiently, there is little production of excess sludge.
4. Because it can use microorganisms that work actively even in cold winter areas like Hokkaido, it can be used for dairy farming in Hokkaido.
5. It is possible to treat waste milk, which is said to be difficult to clean because of its high fat and vaccine.

It is a conceptual diagram which shows the structure of the first half part of a waste milk processing apparatus. It is a notch figure which shows the structure of the second half part (waste water treatment apparatus) of a waste milk processing apparatus. It is nine photographs which show the appearance of the first half part of a waste milk processing apparatus. It is a photograph of an oyster shell used in the present invention. It is a photograph of the carbon fiber used for a carbon fiber aeration tank. It is a figure which shows the procedure of the process in the latter half part (drainage processing apparatus) of a waste milk processing apparatus. It is a transparency comparison photograph of each part in the latter half part (waste water treatment apparatus) of a waste milk processing apparatus. It is a line graph which shows the measurement result of BOD (Biochemical Oxygen Demand: biochemical oxygen demand) from 971 days after starting installation of an apparatus. It is a line graph which shows the measurement result of the transparency until 971 days after starting installation of an apparatus. Measurement results of COD (Chemical Oxygen Demand) from the installation of the waste milk processing equipment to more than 110 days are shown in the first sedimentation separation tank, the second precipitation separation tank, and the UASB tank. It is a line graph shown about. COD (Chemical Oxygen Demand) measurement results from the installation of the waste milk processing equipment up to more than 110 days are used for the first oyster shell contact aeration tank, rocking bed aeration tank It is a line graph shown about a 1st tank, a carbon fiber aeration tank, and an advection / sedimentation tank. The waste milk treatment apparatus of the present invention is charged with 120 liters of waste milk every day and operated for 118 days. It is a table | surface shown about a tank, a sedimentation separation tank 2nd tank, a UASB tank, an anaerobic filter bed tank, an oyster shell contact aeration tank 1st tank, a rocking bed aeration tank 1st tank, and a carbon fiber aeration tank.

Hereinafter, embodiments of the waste milk processing apparatus of the present invention will be described with reference to the drawings.
FIG. 1 is a conceptual diagram showing the configuration of the first half of a waste milk processing apparatus. The waste milk processing apparatus of the present invention is roughly divided into two parts, a first half part and a second half part. The first half is a device that exclusively processes waste milk, and this alone may not lead to the release standard. The latter half is a device that treats wastewater generated in milking facilities. The water that has been treated in the first half will surely reach the discharge standard after being treated in the second half.

  The sedimentation tank 1st tank 10 of FIG. 1 is a part which throws away waste milk first. The waste milk that has been introduced decays, ferments and becomes acidic over time. And it separates and settles by gravity. The supernatant of the first sedimentation tank 10 is further separated and settled by the second sedimentation tank 2. The sludge concentration storage tank 12 is a tank that concentrates and stores the sludge precipitated in the two precipitation separation tanks described above. Concentrated sludge and floating scum (such as fat) are assembled using a slurry pump and transported to a composting plant to help make compost.

Next, the water processed through the precipitation separation tank first tank 10, the precipitation separation tank second layer 11, and the sludge concentration storage tank 12 is caused to flow from the bottom of the reaction tank of the UASB tank 13. The UASB tank 13 uses an upflow anaerobic sludge filter bed method / UASB (Upflow Anaerobic Sludge Blanket), and a biologically formed sludge bed is formed in the reaction tank. The microorganisms necessary for this reaction tank are equipped with microorganisms that become seeds when the UASB tank is installed. This UASB method may be a known one. The water introduced into the UASB tank 13 passes through the sludge bed and flows upward. This sludge bed holds anaerobic bacteria (bacteria that dislike oxygen), and biologically decomposes organic substances into final products containing methane (CH ₄ ) and carbon dioxide (CO ₂ ) (anaerobic) Sexual digestion). The UASB method is characterized in that sludge can be granulated to retain a high concentration of organisms.

  In the UASB tank 13, the free gas and the gas released from the sludge are collected in a gas collection lid (not shown) installed at the top of the reaction tank. The liquid containing residual solids and biological particles is separated into solid and liquid in the sedimentation basin. The separated solid matter settles, passes through the baffle plate, and returns to the surface of the sludge bed.

  The water that has undergone the treatment of the UASB tank 13 is then purified by the anaerobic filter bed tank 20. A reaction tank filled with a solid filter medium is used. Anaerobic bacteria are grown and held on the surface of the solid filter medium. The wastewater is purified by flowing upward while in contact with the filter medium.

  Thereafter, sludge is stored in the second sludge concentration storage tank, and the treated water is in contact with the oyster shell in the first oyster shell contact aeration tank 22 while aerobic microorganisms (bacteria and mold are present).・ Oxygen necessary for the activity of protozoa is sent by an aeration device (blowing air into the tank with a blower) and purified by aerobic bacteria. As the oyster shell, the shell after removing the contents of the shell as shown in FIG. 4 (a) can be used together with a net and installed in a bowl shape as shown in FIG. 4 (b). FIG. 4 (c) shows a state in which the cocoon-shaped oyster shells collected in such a manner are deposited.

The water that has passed through the first oyster shell contact aeration tank 22 is aerated in the first swing tank aeration tank 23 to feed air, thereby activating the activity of microorganisms while shaking the string-like contact material. And purified. Here, as the string-like contact material, “string-like contact material PV-45 for biofilm treatment” sold by TBR Corporation of Toyokawa City, Aichi Prefecture can be used. This string-like contact material is obtained by processing a large fiber of polyvinylidene chloride into a long string shape by processing into a mall shape, a specific surface area of 1.4 m ² / m, and a porosity of 99% or more, A wide variety of microorganisms can live at the same time. A large number of PVC pipes are arranged in parallel at an interval of 10 centimeters on the upper part of the first swinging tank aeration tank 23 (the same applies to the second swinging tank aeration tank described later). . And the upper end of a string-like contact material is fixed to each of the PVC pipes at intervals of 10 centimeters, and the lower end hangs down so as to reach the bottom of the swinging aeration tank. The air discharged from the aeration pump is made from the vicinity of the bottom of the swing floor aeration tank. Due to the aeration, the string-like contact material swings and comes into contact with the wastewater to be treated. Aerobic bacteria grow on the surface layer of the string-like contact material, and anaerobic bacteria are generated in the center. These bacteria are generated and stored by continuing to operate the apparatus as an exhaust milk treatment apparatus. Anaerobic bacteria generated at the center of the string-like contact material ingest aging excrement of aerobic bacteria, and a well-balanced food chain occurs. Therefore, excess sludge is reduced. In addition, since higher organisms can be grown, dephosphorization by algae, rotifers, and daphnia can be achieved. Furthermore, since nitric acid bacteria grow and digestion of ammonia nitrogen is promoted, denitrification by denitrifying bacteria can be performed. Since there is no need for return sludge, almost no maintenance is required, and uniform and stable treatment can be performed.

  The carbon fiber aeration tank 30 is obtained by bundling carbon fibers like hair (FIG. 5 (a)), dipping in a tank (FIG. 5 (b)), and aeration to remove pollutants and microorganisms in the water. It adheres (FIG. 5C). The contact aeration method using carbon fiber was developed with the cooperation of Prof. Akira Kojima of Gunma National College of Technology.

  The water in which the carbon fiber has been purified by the aeration tank 30 passes through the advection / sedimentation tank 31 and is transferred to the latter half of the apparatus (drainage treatment apparatus) shown in FIG. The advection / sedimentation tank 31 is a tank that performs solid-liquid separation by gravity so that only the supernatant is transferred to the next step.

  Each tank shown in FIG. 1 can be made of, for example, FRP (fiber reinforced plastic). FRP silos can also be used. If strength is particularly required, RC construction (reinforced concrete construction) is used. FIG. 3 is nine photographs showing the appearance of the first half of the waste milk processing apparatus. 3 (a) shows the first tank of the sedimentation separation tank, FIG. 3 (b) shows the second tank of the precipitation separation tank, FIG. 3 (c) shows the sludge concentration storage tank, and FIG. 3 (d) shows the UASB. 3 (e) shows an anaerobic filter bed tank, FIG. 3 (f) shows an oyster shell contact aeration tank, FIG. 3 (g) shows a rocking bed aeration tank, FIG. ) Shows a carbon fiber aeration tank, and FIG. 3I shows a precipitation tank.

  FIG. 2 is a cutaway view showing the configuration of the latter half portion (drainage treatment apparatus) of the waste milk treatment apparatus. This device shown in FIG. 2 is a wastewater treatment device already sold by the applicant, and has a track record of purifying wastewater (excluding waste milk) generated in a milking facility to a discharge standard.

  The apparatus of FIG. 2 includes a screen 40, a flow rate adjustment tank 41, a sludge concentration storage tank third tank 45, an oyster shell contact aeration tank second tank 50, a rocking floor aeration tank second tank 60, a precipitation tank. 70, the disinfection tank 80, and the discharge tank 90 are comprised integrally. Air is blown into the tank that needs aeration by an aeration device (blower 35). The splash type screen 40 is provided with a screen for the purpose of separating and removing large impurities. In order to prevent clogging of the screen, the screen is constantly aerated. The flow rate adjusting tank 41 is a tank for preventing the sewage from flowing into the subsequent processing tank at a time and sending it by a fixed amount.

  The sludge concentration storage tank third tank 45 is a tank having the same functions as the sludge concentration storage tank first tank 12 and the sludge concentration storage tank second tank 21 of FIG. The oyster shell contact aeration tank second tank 50 is a tank having the same function as the oyster shell contact aeration tank first tank 22 of FIG. The swing bed aeration tank second tank 60 is the same tank as the swing bed aeration tank first tank of FIG. The sedimentation tank 70 is a tank having the same function as the advection / sedimentation tank 31 of FIG.

  The sterilization tank 80 is a tank that performs sterilization immediately before discharge. For example, disinfection using sodium hypochlorite is performed. The discharge tank 90 is a tank in which treated water to be discharged is stored.

  FIG. 6 is a diagram illustrating a processing procedure in the latter half of the waste milk processing apparatus (drainage processing apparatus). The processing proceeds approximately in the order of the tanks shown in FIG. The sludge stored in the settling tank 70 is returned to the sludge concentration storage tank third tank 45. A part of the sludge in the sludge concentration storage tank third tank 45 is returned to the flow rate adjustment tank 41.

  FIG. 7 is a perspective comparison photograph of each part in the latter half part (waste water treatment apparatus) of the waste milk treatment apparatus. 7 (a) shows the flow rate adjustment tank 41, FIG. 7 (b) shows the sludge concentration storage tank third tank 45, and FIG. 7 (c) shows the oyster shell contact aeration tank second tank 50, FIG. 7 (d). ) Is a swing bed aeration tank second tank 60, and FIG. 7 (e) is one in which the treated water of the settling tank 70 is put in a transparent cup and taken from the side. It can be seen that the water is transparent as the processing by this apparatus proceeds.

  FIG. 8 is a line graph showing measurement results of BOD (Biochemical Oxygen Demand) from 971 days after the installation of the apparatus of FIG. 2 is started. The horizontal axis represents the number of days, and the vertical axis represents the BOD value. 120 mg / l is the discharge standard and is indicated by a horizontal line. The BOD value is not stable by the 72nd day after the installation of the apparatus is started. This is because it took time to adjust until the microorganisms settled. After the 90th day, the release standard has been cleared. Around 940 days, a waste milk processing unit was added. After that, it can be seen that the value of BOD is further improved.

  FIG. 9 is a line graph showing the measurement results of the transparency until 971 days after the installation of the apparatus of FIG. 2 is started. After 276 days, the transparency is 20 centimeters or less and is stable.

  FIG. 10 shows the results of COD (Chemical Oxygen Demand) measurement from the installation of the waste milk processing apparatus of FIG. 1 to over 110 days. It is a line graph shown about a tank 2nd tank and a UASB tank. Initially, it takes time for the microorganisms to settle. It can be seen that the effect of purification has appeared since the 10th day, and that the effect has increased as the number of days increases.

  FIG. 11 shows the results of measuring COD (Chemical Oxygen Demand) from the installation of the waste milk treatment apparatus of FIG. 1 to over 110 days. It is a line graph shown about a rocking | floating floor aeration tank 1st tank, a carbon fiber aeration tank, and an advection / sedimentation tank. The effect appears after the 18th, and a remarkable effect can be seen around the 100th day.

  FIG. 12 shows the results of BOD and COD measured under the witness of the National Institute for Research and Development after 120 liters of waste milk is put into the waste milk processing apparatus of FIG. 1 every day and operated for 118 days. Separation tank first tank, precipitation separation tank second tank, UASB tank, anaerobic filter bed tank, oyster shell contact aeration tank first tank, rocking bed aeration tank first tank, carbon fiber aeration tank is there. After 118 days of operation, the BOD is 1 and the COD is 20, indicating that we are one step closer to the discharge standard. This numerical value is the result of only the first half part (FIG. 1) of the waste milk processing apparatus of the present invention, and after that, purification is performed to the standard where there is no problem of discharge by performing the purification process of the waste water treatment apparatus of FIG. Is possible.

  It can be used in milking facilities. It can also be used when it is necessary to dispose of excess milk in a dairy processing plant.

10 Precipitation separation tank 1st tank 11 Precipitation separation tank 2nd tank 12 Sludge concentration storage tank 1st tank 13 UASB tank 20 Anaerobic filter bed tank 21 Sludge concentration storage tank 2nd tank 22 Oyster shell contact aeration tank 1st tank 23 Moving bed aeration tank 1st tank 30 Carbon fiber aeration tank 31 Advection / sedimentation tank 35 Blower (aeration apparatus)
40 Aeration screen 41 Flow control tank 45 Sludge concentration storage tank 3rd tank 50 Oyster shell contact aeration tank 2nd tank 60 Oscillating floor aeration tank 2nd tank 70 Precipitation tank 80 Disinfection tank 90 Discharge tank

Claims (2)

A waste milk processing device for processing waste milk generated in a milking facility so as to reach a discharge standard,
First settling tank for adding waste milk and subjecting to settling process,
Precipitation separation treatment is performed in the first precipitation separation tank, the treated water that has flowed out is added, and the second precipitation separation tank in which the precipitation separation treatment is performed again,
The sludge concentration storage tank first tank that concentrates sludge by the treatment of the second precipitation separation tank and the first precipitation separation tank and sucks and removes the slum that floats and the concentrated sludge by a slurry pump,
The water that has passed through the treatment of the first tank of the sludge concentration storage tank, the first tank of the precipitation separation tank, and the second tank of the precipitation separation tank is subjected to an upward flow anaerobic sludge filter bed method / UASB (Upflow Anaerobic Sludge Blanket). A UASB tank to be processed;
An anaerobic filter bed tank that performs anaerobic treatment on the water subjected to the treatment of the UASB tank;
A second tank for concentration and storage of sludge for concentrating excess sludge generated by the treatment by the anaerobic filter bed tank;
A oyster shell contact aeration tank first tank that is charged with water that has been treated by the anaerobic filter bed tank and aerated using oyster shell as a contact material;
A rocking bed aeration tank first tank that uses a string-like contact material to aerate the water that has been treated by the oyster shell contact aeration tank first tank,
A carbon fiber aeration tank that performs contact aeration using carbon fiber on the water that has undergone the treatment in the first aeration floor aeration tank;
An advection / sedimentation tank that precipitates sludge and advects the supernatant to the water that has undergone the treatment of the carbon fiber aeration tank;
An aeration type screen for introducing water transferred from the advection / sedimentation tank together with other drainage in the milking facility;
A flow rate adjusting tank for adjusting the flow rate of water charged into the aerated screen;
Oyster shell contact aeration tank second tank for aeration by contacting with the oyster shell against water that has passed through the flow rate adjustment tank,
A swing-bed aeration tank second tank that uses a string-like contact material for the water that has been treated by the oyster shell contact aeration tank second tank,
A sedimentation tank that performs a precipitation separation process on the water that has undergone the treatment in the second aeration bed aeration tank;
A third sludge concentration storage tank for concentrating excess sludge generated in the settling tank;
A disinfection tank for performing a treatment for killing pathogenic microorganisms on the supernatant separated in the settling tank;
A waste milk processing apparatus comprising: a discharge tank for storing water disinfected in the disinfection tank, and processing the waste milk up to a discharge standard. A waste milk processing method for processing waste milk generated in a milking facility so as to reach a discharge standard,
A first precipitation separation step in which waste milk is introduced into the first precipitation separation tank and subjected to precipitation separation;
In the first precipitation separation step, a precipitation separation process is performed, and the second precipitation separation step in which the treated water that has flowed out is added and the precipitate separation process is performed again;
A first sludge concentration and storage step of concentrating sludge by the treatment of the second precipitation separation step and the first precipitation separation step, and sucking and removing the slum that floats and the concentrated sludge by a slurry pump;
UASB which processes the water which passed through the process of this 1st sludge concentration storage step, said 1st precipitation separation step, and said 2nd precipitation separation step using an upflow anaerobic sludge filter bed method and UASB (Upflow Anaerobic Sludge Blanket) Steps,
An anaerobic filter bed step for performing anaerobic treatment on the water subjected to the treatment of the UASB step;
A second sludge concentration storage step for concentrating excess sludge generated by the treatment by the anaerobic filter bed step;
A first oyster shell contact aeration step in which water subjected to the treatment by the anaerobic filter bed step is introduced and aerated using oyster shell as a contact material;
A first rocking floor aeration step for aeration using a string-like contact material to the water that has undergone the treatment by the first oyster shell contact aeration step;
A carbon fiber aeration step for performing contact aeration using carbon fiber on the water that has undergone the treatment by the first swing bed aeration step;
An advection / sedimentation step for precipitating sludge and advancing the supernatant for water that has undergone the carbon fiber aeration step;
An aeration type screen charging step for charging water transferred from the advection / sedimentation step together with other drainage in the milking facility;
A flow rate adjusting step for adjusting the flow rate of the water charged in the aeration type screen charging step;
A second oyster shell contact aeration step in which the water that has undergone the flow rate adjustment step is aerated in contact with the oyster shell;
A second rocking bed aeration step for aeration using a string-like contact material to the water that has undergone the treatment by the second oyster shell contact aeration step;
A precipitation step for subjecting the water subjected to the treatment by the second rocking bed aeration step to a precipitation separation treatment;
A third sludge concentration storage step for concentrating excess sludge generated in the precipitation step;
A disinfection step of performing a treatment to kill pathogenic microorganisms on the supernatant separated in the precipitation step;
And a discharge step for storing the water disinfected in the disinfection step, wherein the waste milk is processed until the discharge standard is reached.