JP2006297336A - Waste water treating method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waste water treating method and apparatus capable of uniformly maintaining the BOD concentration, pH and chloride concentration, etc., of waste water to be treated to be introduced from a concentration adjustment tub installed on the upstream side of an aerating tank to the aerator and performing efficient activated sludge treatment at all times without generating the impairment of activated sludge inside the aerating tank. <P>SOLUTION: The two concentration adjustment tubs 2a and 2b are installed in parallel on the upstream side of the aerating tank 3. While the waste water to be treated is made to flow in, stored, aerated and agitated in one concentration adjustment tub, concentration adjusted waste water is introduced to the aerating tank in the other concentration adjustment tub. By alternately performing that, the inflow of the waste water to be treated and the introduction to the aerating tank of the concentration adjusted waste water are not simultaneously performed in a single concentration adjustment tub. As a result, there is no risk of temporarily introducing the concentration unadjusted waste water to which the concentration adjustment is not performed in the concentration adjustment tub to the aerator, the uniformly concentration adjusted waste water is introduced to the aerating tank at all times, and the effective activated sludge treatment in the aerator is performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a wastewater treatment method capable of effectively performing activated sludge treatment by making the organic matter concentration, pH, chlorine concentration, etc. of treated wastewater uniform when treating wastewater by aerobic treatment using activated sludge. The present invention relates to a wastewater treatment apparatus.

  The activated sludge method has been widely used as a method for purifying sewage such as sewage, factory effluent, and livestock effluent. This activated sludge method is a method in which wastewater to be treated is introduced into an aeration tank, and contaminants mainly composed of organic substances in non-treated wastewater by aerobic microorganisms (activated sludge) are oxidatively decomposed and purified while aeration is performed.

  In the purification treatment by such activated sludge method, it is important to maintain the organic substance concentration, pH, chlorine concentration, etc. in the treated wastewater uniformly in order to keep the activated sludge treatment capacity in the aeration tank good. . For example, the BOD concentration of the wastewater to be treated introduced into the aeration tank is ideally 500 mg / L or less, and when wastewater with a BOD concentration higher than this is introduced, the activated sludge becomes a nap and further died. In some cases, functional sludge may be impaired.

  Therefore, instead of directly introducing the treated wastewater into the aeration tank, the wastewater is temporarily stored in the adjustment tank provided on the upstream side of the aeration tank, and the concentration of the pollutant is made uniform to some extent, and then introduced into the aeration tank ( For example, Patent Document 1), a method of introducing an air into an aeration tank after introducing organic substance into an adjustment tank to reduce the molecular weight of an organic substance and reducing the concentration of pollutants (Patent Document 2) have been proposed.

  An example of the processing apparatus which installed the adjustment tank which once stores the to-be-processed wastewater in the upstream of an aeration tank is shown in FIG. The treated wastewater from various wastewater generation sites sequentially flows into the raw water tank 10, and the inflowed treated wastewater is immediately pumped by the pump P1 to the concentration adjusting tank 20, where it is stored for a certain period of time, and the organic matter concentration, pH, chlorine Concentration-adjusted wastewater with uniform concentration. The concentration-adjusted waste water is continuously pumped from the concentration adjustment tank 20 to the aeration tank 30 by the pump P2, while the flow rate is adjusted. Here, air bubbles blown into the aeration tank 30 from the diffuser pipe 31 connected to the aeration blower B1. Then, the wastewater whose concentration has been adjusted is aerated and stirred together with the activated sludge to perform the activated sludge treatment, and the pollutants in the wastewater are removed. The treated wastewater from which the pollutants have been removed is filtered by the membrane unit 40 and separated into activated sludge (excess sludge) and treated wastewater. Bubbles are blown to the membrane unit 40 from the diffuser pipe 32 connected to the aeration blower B2, thereby preventing the activated sludge from adhering to the membrane. The separated treated waste water is extracted from the aeration tank 30 by the pump P3 and discharged.

JP-A-8-257582 JP 2004-202381 A

  However, even when the concentration adjustment tank 20 for storing the treated wastewater is installed upstream of the aeration tank 30 as shown in FIG. 2, the inflow of the wastewater into the concentration adjustment tank 20 and the outflow from the adjustment tank 20 to the aeration tank 30 As a result, the drainage is not sufficiently retained in the concentration adjustment tank 20 and there is a risk that the concentration adjustment tank 20 will flow out to the aeration tank 30 before the concentration adjustment has been performed. If wastewater whose concentration has not been adjusted in the adjustment tank 20 is temporarily introduced into the aeration tank 30, the activated sludge in the aeration tank 30 has a functional failure, and effective purification treatment cannot be performed. There may be situations where the facility must be shut down. Therefore, it is necessary to install a large-capacity adjustment tank 20 that can store the wastewater generated until the function of the activated sludge is restored.

  Therefore, the present invention uniformly maintains the organic matter concentration, pH, chlorine concentration, etc. of the wastewater to be treated introduced from the adjustment tank installed upstream of the aeration tank into the aeration tank, thereby preventing the functional sludge from functioning in the aeration tank. The purpose of the present invention was to provide an improved wastewater purification method and wastewater purification device that can always perform an efficient activated sludge treatment without causing them, and that does not require the installation of a large-capacity adjustment tank. Is.

That is, in the wastewater treatment method of the present invention, the pollutant concentration in the wastewater to be treated is obtained by flowing and storing the wastewater to be treated into any one of at least two concentration adjustment tanks arranged in parallel and aeration and stirring for a certain time. After the pH is made uniform, this concentration-adjusted wastewater is introduced into the aeration tank to perform activated sludge treatment, and the wastewater to be treated flows into and is stored in another one of the concentration-adjustment tanks and aerated for a certain period of time. The process A and the process include the process B in which the pollutant concentration and pH of the wastewater to be treated are made uniform by stirring, and then the activated water is treated by introducing the concentration-adjusted wastewater into the aeration tank. By alternately switching B, inflow of treated wastewater into any of the concentration adjustment tanks and introduction of concentration adjusted wastewater from any of the concentration adjustment tanks into the aeration tank can be performed continuously. As It is an octopus and features.
In the present specification, the term “contaminant concentration” is used as a generic term for the concentrations of organic substances, SS, n-Hex, N, P, Cl and the like contained in waste water.
In such a method of the present invention, if necessary, neutralization and / or chlorine removal can be performed by introducing a pH adjusting agent and / or a chlorine reducing agent into the wastewater to be treated in the concentration adjusting tank.

Furthermore, the waste water treatment apparatus of the present invention is a concentration adjusting tank with aeration and stirring means arranged in parallel for inflow and storage of treated waste water,
An aeration tank that performs activated sludge treatment by introducing a concentration-adjusted wastewater whose concentration and pH are made uniform in the concentration-adjusting tank, and inflow and storage of treated wastewater into any one of the concentration-adjusting tanks To alternately switch between introduction of the concentration-adjusted wastewater into the aeration tank and inflow, storage, and introduction of the concentration-adjusted wastewater into the aeration tank. Switching means.
In such an apparatus of the present invention, if necessary, the concentration adjusting tank can be provided with a pH adjusting agent charging means and / or a chlorine reducing agent charging means.

  According to the method and apparatus of the present invention, while the inflow, storage, and aeration and agitation of the wastewater to be treated are performed in one of the at least two concentration adjustment tanks, the concentration adjusted wastewater is discharged in another one of the concentration adjustment tanks. Therefore, the inflow of the treated wastewater and the introduction of the concentration-adjusted wastewater into the aeration tank are not performed simultaneously in one concentration adjustment tank. As a result, there is no risk that unconcentrated wastewater whose concentration has not been adjusted in the concentration adjustment tank will be temporarily introduced into the aeration tank, and wastewater whose concentration is constantly adjusted is introduced into the aeration tank. In addition, effective activated sludge treatment can be performed in the aeration tank.

  Furthermore, since treated wastewater with a uniform pollutant concentration and pH can be treated in an aeration tank, wastewater treated with high BOD concentration, strong acid, strong alkali, or high chlorine concentration can be temporarily introduced into the aeration tank. The risk of causing the activated sludge functional failure is reduced, and there is no need to install a large-capacity concentration adjusting tank for storing the wastewater generated until the function of the activated sludge is restored.

  In the following, the present invention will be described by taking as an example the treatment of equipment wastewater used for milking in dairy farming and the treatment of parlor wastewater containing waste milk. Milking equipment includes pipeline millers and bulk coolers. Pipeline milkers are a series of devices for collecting milk that is milked by a milker that is attached to a cow's breast and pumping it to a bulk cooler by means of a pump. It is a device that cools and stores raw milk until it comes to collection. The washing wastewater of these devices contains strong acid detergents, strong alkaline detergents, sterilized chlorine, and equipment residual milk, which causes environmental pollution. Waste milk means colostrum produced after childbirth or milk after mastitis treatment, which can be shipped without being shipped. The BOD concentration of colostrum is 120,000 mg / L, and the BOD concentration of milk is 78. Since it is very high at 1,000,000 mg / L, it is impossible to purify it alone.

In particular, when treating the parlor waste water, it is necessary to make the concentration uniform by temporarily storing and mixing the washing waste water having a low BOD concentration and the waste milk having a high BOD concentration in a concentration adjusting tank. However, when a single concentration adjustment tank as shown in FIG. 2 is used, there is a risk that the inflow of the wastewater to be treated into the concentration adjustment tank and the outflow to the aeration tank occur at the same time. As a result, treated wastewater containing a large amount of strong acid, strong alkali and high chlorine concentration washing wastewater or treated wastewater containing a large amount of waste milk temporarily flows into the aeration tank, and the function of activated sludge in the aeration tank. Risk of injury. In addition, it takes one to two weeks until the function of activated sludge is restored, and a large-capacity concentration adjusting tank is required to store the parlor drainage generated during that period. For example, in a 50-dairy dairy farm, about 2m ³ of parlor wastewater is generated per day, and about 28m ³ of parlor wastewater is discharged in 2 weeks. A tank for storing such a large volume of wastewater is installed. This is difficult in terms of cost.

  Therefore, in the present invention, as shown in the embodiment of FIG. 1, two concentration adjusting tanks are installed in parallel on the upstream side of the aeration tank, and one concentration adjusting tank and the other concentration adjusting tank are alternately changed. By operating in such a manner, there is no danger that the inflow of the wastewater to be treated into the concentration adjustment tank and the outflow to the aeration tank may occur simultaneously when a single concentration adjustment tank is used.

  That is, in the wastewater treatment apparatus of the present invention shown in the schematic explanatory diagram of FIG. 1, two concentration adjusting tanks 2a and 2b for inflowing and storing treated wastewater are arranged in parallel, and the concentration of pollutants and pH in the concentration adjusting tank are set. An aeration tank 3 for introducing activated sludge treatment by introducing a concentration-adjusted wastewater that has been made uniform is placed into the aeration tank 3 for inflow and storage of treated wastewater into one concentration-adjusted tank 2a and concentration-adjusted wastewater. And pumps P1 to P4 as switching means for alternately switching inflow of the treated wastewater into the other concentration adjustment tank 2b, storage, and introduction of the concentration-adjusted wastewater into the aeration tank 3 Yes. Each of the concentration adjustment tanks 2a and 2b includes an aeration blower B1, an aeration tube 5 connected to the aeration blower B1, and an aeration blower B2 and an aeration tube 6 connected to the aeration blower B1, respectively.

  With reference to FIG. 1, the Example of the waste water treatment method of this invention is described below. Parlor wastewater consisting of various treated wastewater such as pipeline milker washing wastewater, bulk cooler washing wastewater, waste milk, and washing machine wastewater is allowed to flow into the raw water tank in the order of discharge. In this embodiment, the concentration adjusting tanks 2a and 2b are operated alternately by changing one day.

[Driving on the first day]
Various treated wastewaters that flow into the raw water tank on the first day are pumped to the concentration adjusting tank 2a by the pump P1 immediately after the inflow, and the treated wastewater for one day is stored here. During this time, the pump P3 that pumps the wastewater from the concentration adjustment tank 2a to the aeration tank 3 is stopped. Table 1 summarizes the discharge date and time, drainage type, discharge order, and discharge amount of various treated wastewater. In addition, in the Example in Table 1, the various to-be-processed waste_water | drain discharged | emitted on the evening of the previous day and the morning of the day is made into the to-be-processed waste water for one day.

  When the various treated wastewater for the first day of the first day is stored in the concentration adjustment tank 2a, the operation of the pump P1 is stopped, and the various treated wastewaters that continuously flow into the raw water tank 1 on the second day. The pump P2 is operated so that the pressure can be pumped to the concentration adjusting tank 2b. In the concentration adjustment tank 2a, the stored treated wastewater for one day is aerated and agitated by bubbles blown into the concentration adjustment tank 2a from the diffuser pipe 5 connected to the aeration blower B1, and during this time the pump P3 is in a stopped state. Therefore, the treated wastewater does not flow out from the concentration adjusting tank 2a to the aeration tank 3, and the various treated wastewater is effectively mixed uniformly in the concentration adjusting tank 2a, and pH, BOD, COD, SS, n -Hex, TN, TP, Cl, etc. can be used as a drainage adjusted in concentration (“total drainage” in Table 1) having a predetermined value.

  In the state where the pump P3 is stopped and the wastewater from the concentration adjustment tank 2a is not pumped to the aeration tank 3, the pump P4 is operated, and the concentration-adjusted wastewater for the previous day mixed uniformly in the concentration adjustment tank 2b. The activated sludge is processed by being pumped to the aeration tank 3.

  The concentration-adjusted waste water for one day (first day) uniformly mixed is continuously pumped from the concentration adjustment tank 2a to the aeration tank 3 while the flow rate is adjusted by starting the operation of the pump P3. An amount of wastewater corresponding to the day (first day) is treated with activated sludge in the aeration tank 3 for one day and extracted. The activated sludge treatment in the aeration tank 3 is the same as that described with reference to FIG. That is, the concentration-adjusted waste water pumped to the aeration tank 3 is aerated together with waste water and activated sludge that are always present in the aeration tank 3 by bubbles blown into the aeration tank 3 from the diffuser pipe 7 connected to the aeration blower B3. The activated sludge is agitated and the pollutants in the waste water are decomposed and removed. The treated wastewater from which the pollutant has been decomposed and removed is filtered by the membrane unit 4 and separated into activated sludge (excess sludge) and treated wastewater. Bubbles are blown onto the membrane unit 4 from the diffuser tube 8 connected to the aeration blower B4 to prevent the activated sludge from adhering to the membrane. The separated treated waste water is extracted from the aeration tank 3 by the pump P5 and discharged.

[Driving on the second day]
The pump P1 is stopped when the pump P1 is completely pumped from the raw water tank 1 to the concentration adjustment tank 2a for all the treated wastewater for the first day of the first day, and then the pump P2 is operated. Immediately after the various treated wastewater flowing into the raw water tank 1 flows into the concentration water tank 2, it is pumped to the concentration adjusting tank 2 b. During this time, the pump P4 that pumps waste water from the concentration adjustment tank 2b to the aeration tank 3 is stopped. When various treated wastewater for the first day of the second day is stored in the concentration adjustment tank 2b, the operation of the pump P2 is stopped, and various treated wastewater flowing into the raw water tank 1 on the third day The pump P1 is operated so that it can be pumped to the concentration adjusting tank 2a. In the concentration adjustment tank 2b, the stored treated wastewater for one day is aerated and agitated by bubbles blown into the concentration adjustment tank 2b from the air diffuser 6 connected to the aeration blower B2, and during this time, the pump P4 is stopped. Therefore, the treated wastewater does not flow from the concentration adjusting tank 2b to the aeration tank 3, and the various treated wastewater is effectively and uniformly mixed in the concentration adjusting tank 2b, so that the concentration adjusted wastewater can be obtained. . Concentration-adjusted wastewater obtained on the first day of pH, BOD, COD, SS, n-Hex, TN, TP, Cl, etc. It can be set to a value substantially similar to the value in ("General drainage" in Table 1).

  Uniformly mixed one day (second day) concentration adjusted waste water is continuously pumped from the concentration adjusting tank 2b to the aeration tank 3 while the flow rate is adjusted by starting the operation of the pump P4. An amount of waste water corresponding to the daily amount is treated with activated sludge in the aeration tank 3 for one day and extracted. The activated sludge treatment in the aeration tank 3 is performed in the same manner as the treatment on the first day.

  As described in detail above, in the embodiment shown in FIG. 1, the pump P1 and the pump P4 are operated in the operation on the first day and the pumps P2 and P3 are stopped, and the pump in the operation on the second day. P2 and pump P3 are operated, and pump P1 and pump P4 are stopped. Thus, in the concentration adjustment tank 2a and the concentration adjustment tank 2b, “inflow of treated water, aeration agitation” and “introduction of concentration-adjusted wastewater into the aeration tank” are alternately performed every day, There is no danger that “inflow of treated water, aeration and agitation” and “introduction of concentration-adjusted wastewater into the aeration tank” may be performed at the same time in a single concentration adjustment tank. However, the inflow of the water to be treated into one of the two concentration adjustment tanks and the introduction of the concentration-adjusted waste water from either of the two concentration adjustment tanks into the aeration tank are continuously performed.

  In the embodiment of the purification treatment of the above-described parlor wastewater, the pH, BOD, COD, SS, n-Hex, TN, TP, Although the value of Cl and the like could be adjusted to a value capable of treating activated sludge, the pH adjusting agent introduction pipes 2c and 2e and the chlorine reducing agent introduction pipes 2d and 2f provided in the respective concentration adjustment tanks 2a and 2b were adjusted as necessary. A pH adjusting agent and / or a chlorine reducing agent can be added to adjust the pH of the waste water and / or remove chlorine.

  In the embodiment of FIG. 1, two concentration adjustment tanks are arranged in parallel and operated alternately every day. However, the amount of wastewater treatment, the capacity of the concentration adjustment tank, the aeration stirring time in the concentration adjustment tank, etc. Depending on the processing conditions, three or more concentration adjusting tanks may be installed in parallel and alternately operated one by one.

  Furthermore, although the above-mentioned Example gave and demonstrated the example of processing of livestock wastewater such as parlor wastewater, the present invention is not limited to the treatment of livestock wastewater, but various treated wastewater such as sewage, human waste, and various factory wastewaters. It can be applied to activated sludge treatment.

It is a conceptual explanatory view showing one example of the waste water treatment equipment by the present invention. It is a conceptual explanatory drawing which shows an example of the conventional waste water treatment equipment.

Explanation of symbols

1: Raw water tank 2a, 2b: Concentration adjustment tank 2c, 2e: pH adjuster charging pipe 2d, 2f: Chlorine reducing agent charging pipe 3: Aeration tank 4: Membrane units P1-P5: Pump B1-B4: Aeration pump

Claims (4)

  After the treated wastewater flows into one of at least two concentration adjustment tanks arranged in parallel and stored and aerated and stirred for a certain period of time, the pollutant concentration and pH of the treated wastewater are made uniform, and then this concentration adjustment is performed. Process wastewater by introducing activated wastewater into the aeration tank and subjecting the treated wastewater to another one of the concentration-adjusting tanks, storing and aeration and agitation for a certain period of time to contaminate the wastewater to be treated After making the concentration and pH uniform, the waste water having the adjusted concentration is introduced into the aeration tank and subjected to activated sludge treatment, and the step A and the step B are alternately performed, Wastewater treatment characterized in that inflow of treated wastewater into any of the concentration adjustment tanks and introduction of concentration adjusted wastewater from any of the concentration adjustment tanks into the aeration tank can be performed continuously Method.   The wastewater treatment method according to claim 1, wherein pH adjustment and / or chlorine removal is performed by introducing a pH adjuster and / or a chlorine reducing agent into the wastewater to be treated in the concentration adjustment tank. A concentration adjusting tank with aeration and stirring means arranged in parallel for inflow and storage of treated wastewater;
An aeration tank that performs activated sludge treatment by introducing a concentration-adjusted wastewater whose concentration and pH are made uniform in the concentration-adjusting tank, and inflow and storage of treated wastewater into any one of the concentration-adjusting tanks To alternately switch between introduction of the concentration-adjusted wastewater into the aeration tank and inflow, storage, and introduction of the concentration-adjusted wastewater into the aeration tank. The waste water treatment apparatus characterized by having a switching means.   4. The waste water treatment apparatus according to claim 3, wherein the concentration adjusting tank includes a pH adjusting agent charging unit and / or a chlorine reducing agent charging unit.

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