JP4790406B2 - Ozone disinfection equipment - Google Patents

Description

  The present invention relates to an ozone disinfection device for sewer inflow water.

An ozone disinfection device that disinfects a large amount of untreated inflow sewage in a combined sewage treatment plant where rainwater and sewage are combined and treated on the same treatment line has not been put into practical use until now. A system (ozone disinfection device) as shown in FIG. 9 is considered based on technology, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2000-202472), Patent Document 2 (Japanese Patent Laid-Open No. 2004-122105), and the like. .
This ozone disinfection device adopts a constant ozone injection rate control system as in Patent Document 1 that changes the ozone injection rate by changing the ozone concentration of the ozone generator according to the inflow flow rate of the water to be treated. Composed. That is, the ozone disinfection device shown in FIG. 9 collects the ozone generator 1 that generates high-concentration ozone, the raw material gas supply device 2 that supplies air or oxygen as the raw material of ozone to the ozone generator, and the inflow sewage. Ozone is sucked in by using the suction force of the impeller of the pump, and the in-house power generator 4 that supplies electricity to the ozone generator 3, ozone generator, etc. that mixes inflow sewage and ozone using the stirring force of the impeller The ozone decomposing unit (exhaust ozone decomposing unit) 5 that treats ozone (exhaust ozone) that has not been absorbed by the inflowing sewage and returns it to the air. The electric power detected and adjusted to the ozone generator is adjusted and controlled by a power adjusting device such as an inverter.
Thus, according to the ozone injection rate constant control, it is possible to reduce the power cost for generating ozone because the ozone concentration is changed according to the change of the inflow flow rate.

When the main component of the reducing substance in the inflowing sewage is ammonia nitrogen, the ammonia nitrogen is highly reactive with oxygen and ozone, so ozone is consumed by the addition of ozone and it can hardly be used for disinfection. It was thought. For this reason, chlorine disinfection has been performed.
Patent Document 3 (Japanese Patent Application Laid-Open No. 4-66190) discloses that ammonia is introduced by adding alkali bromide without adding chlorine and adding alkali bromide to an ammoniacal nitrogen-containing wastewater in the presence of bromine ions. A wastewater treatment method that can oxidize and remove reducing substances such as nitrogen has been proposed.
That is, the wastewater treatment method proposed in Patent Document 3 adds an appropriate amount of alkali bromide to raw water such as river water, lake water, groundwater, industrial wastewater, and domestic wastewater containing reductive nitrogen such as ammonia, This bromine decomposes all or part of the reducing nitrogen in the raw water.

Patent Document 4 (Japanese Patent Laid-Open No. 7-265585) is a related invention of Patent Document 3, but this ammonia nitrogen-containing wastewater treatment apparatus is preferentially ammonia nitrogen in the reducing substance. As a result, the removal of disinfecting substances is hindered, the disinfection efficiency decreases, and ozone consumption increases compared to the case where no reducing substances are present, resulting in uneconomical problems. It is a solution.
In other words, this ammonia nitrogen-containing wastewater treatment apparatus has a sub-reaction tank installed upstream of the main reaction tank in the treatment of ammonia nitrogen-containing waste water by adding ozone in the presence of bromine ions. The reducing substance in the wastewater is oxidized and removed in advance by ozone (from the main reaction tank) of the exhaust gas, and then ammonia nitrogen is removed in the latter main reaction tank by the same treatment as in Patent Document 3.
In addition, there is Patent Document 5 (Japanese Patent Laid-Open No. 2003-275788) as a system for controlling pH. This system relates to sludge treatment different from sewage treatment.

Japanese Unexamined Patent Publication No. 2000-202472 (FIG. 12) JP 2004-122105 A JP-A-4-66190 Japanese Patent Laid-Open No. 7-265885 JP 2003-275788 A

The above-mentioned ozone disinfection device directly injects ozone into the inflowing sewage when the inflowing sewage contains a large amount of ozone, so a large amount of ozone for ineffective consumption is required, and the ozone injection rate is several tens mg. / L ~ 100mg / L of equipment is required, very large installation space compared to other facilities in the treatment plant, and power equipment equivalent to the total power consumption of the treatment plant is required. Considering the above, there is a problem that installation is difficult even if the treatment effect is recognized.
In particular, depending on the content of the reducing substance, ozone that is about 2 to 3 times the amount of ozone injection required for disinfection may be required, which causes a large-scale apparatus.
The necessity of a large amount of ozone for ineffective consumption can be confirmed in the relationship of the number of coliforms to the ozone injection rate shown in FIG. That is, while ozone reacts with the reducing substance, ozone is ineffectively consumed (unnecessary consumption), and a reduction in the number of coliforms cannot be confirmed. However, when the reaction between ozone and the reducing substance is completed, the reduction in the number of coliforms can be confirmed as shown in FIG.
This invention pays attention to this point, and performs disinfection by setting an ozone injection rate that is below the discharge standard in a state where the reduction of the number of coliforms can be confirmed.
In addition, in the methods for treating wastewater containing reducing nitrogen described in Patent Documents 3 and 4, an appropriate amount of alkali bromide is added to raw water, ozone gas or ozone-containing water is injected into the raw water, and the ozone and bromine are used to produce the raw material. Although it decomposes all or part of the reducing nitrogen in water, it is difficult to remove them comprehensively because the inflowing sewage contains many other reducing substances.
In order to solve the problems of the conventional examples described above and to reduce the volume of the ozone disinfection device, this invention removes the reducing substance that reacts with ozone in advance by an oxidation reaction or the like before injecting ozone, The purpose is to reduce the consumption of ozone.

The ozone disinfection device for sewer inflow water according to the present invention includes an ozone generator for generating ozone for disinfecting inflow wastewater, a raw material gas supply device for supplying air or oxygen as the raw material gas for ozone to the ozone generator, ozone dissolution device for mixing and stirring the inflow sewage and the ozone, the inflow sewage processing the unabsorbed ozone ozonolysis apparatus back into the air, and water content of the inflow sewage reducing substances in the inflow sewage The automatic measuring part of the reducing substance that measures iodine consumption in the assay method in real time and the content of the reducing substance measured by the automatic measuring part of the reducing substance are controlled according to the content of the reducing substance before the ozone injection. comprising a processing device before and a control unit for reducing process the reducing substances in the inflow sewage, the inflow sewage flowing into the pretreatment apparatus, rainwater Untreated inflow sewage in a combined sewage treatment plant where sewage joins and is treated in the same treatment line, and the content of reducing substances in the inflow sewage is measured in real time. And reducing the reducing substance, and reducing E. coli by injecting ozone .

According to the ozone disinfection apparatus for sewer inflow water according to the present invention, the inflow sewage is untreated inflow sewage in a combined sewage treatment plant where rainwater and sewage are combined and treated in the same treatment line. The content of reducing substances in the inside is controlled in real time by measuring iodine consumption, reducing the content of reducing substances before ozone injection, and eliminating the ineffective consumption used for ozone other than disinfection. The ozone disinfection apparatus characterized by the above can be obtained, and by eliminating the ineffective consumption of ozone, the reduction of the number of coliforms can be confirmed simultaneously with the ozone injection, and the effect that the disinfection is immediately implemented can be obtained .

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In addition, the same code | symbol shows the same or an equivalent part between each figure.

Embodiment 1 FIG.
Embodiment 1 according to the present invention is intended for untreated inflow sewage in a combined sewage treatment plant where rainwater and sewage merge and are treated in the same treatment line, and is reduced depending on the inflow time and the environment of the basin. High-speed treatment is possible for inflowing sewage whose content of volatile substances fluctuates, or inflowing sewage in rainy weather that greatly exceeds the normal treatment capacity of the treatment plant.
FIG. 1 is a system flow diagram of an ozone disinfection apparatus provided with a chemical liquid injector in Embodiment 1 of the present invention.
Hereinafter, a first embodiment of the present invention will be described with reference to FIG.
In FIG. 1, 1 is an ozone generator that generates high-concentration ozone with a small amount of gas to obtain a high ozone injection rate, and 2 is a raw material gas supply that supplies air or oxygen, which is a raw material of ozone, to the ozone generator 1 The device 3 collects the inflowing sewage, sucks ozone using the suction force of the impeller of the pump, and mixes the inflowing sewage and ozone using the stirring force of the impeller, An in-house power generation device 5 that supplies electricity to an ozone generator or the like is an ozone decomposing device (exhaust ozone decomposing device) that processes exhaust ozone that has not been absorbed by the inflowing sewage and returns it to the air.
In the inflowing sewage in which the content of the reducing substance greatly fluctuates, A reduces the reducing substance before injecting ozone in response to real-time changes in water quality, and the reducing substance reacts with the ozone. Reducing substance automatic measuring unit that measures the content of reducing substances in the inflowing sewage in real time with a pretreatment device that prevents wasteful consumption of ozone generated and enables disinfection at an appropriate ozone injection rate, and Control based on the content of reducing substances measured by this automatic measuring unit for reducing substances (pretreatment of reducing substances in influent sewage) and control to reduce reducing substances in influent sewage before injecting ozone Part.
6 is a reducing substance automatic measuring device that constitutes a reducing substance automatic measuring unit of this pretreatment device. This reducing substance automatic measuring device is composed of sulfide, iron (II) salt, unstable organic matter, unsaturated. A device installed focusing on the fact that iodine consumption consumed by reducing substances such as organic substances having a bond is a water quality analysis item suitable for measuring the content of ineffective consumption that reacts with ozone. The content of reducing substances is measured in real time by automatically measuring iodine consumption by the water quality test method for influent sewage.
7 and 8 are each apparatus which comprises the control part of a pre-processing apparatus, 7 is for the disinfection whose ozone is the use purpose according to content of the reducing substance measured by the reducing substance automatic measuring apparatus 6. A chemical injection device that injects necessary chemicals (oxidizers other than ozone) to be used promptly. Disinfectants used at sewage treatment plants such as sodium hypochlorite are used for the chemicals. The Reference numeral 8 denotes an injection controller that controls the injection amount of the chemical solution, and controls the measurement value of the reducing substance automatic measuring device 6 so as to be a set target that reduces the ineffective consumption of ozone by using feedback control.

Next, the processing operation by the ozone disinfection apparatus in Embodiment 1 will be described.
In general, when the inflowing sewage contains a large amount of reducing substances, disinfecting with ozone requires a large amount of ozone for ineffective consumption. The necessity of such a large amount of ozone can also be confirmed in the relationship of the number of coliforms to the ozone injection rate shown in FIG. In other words, while ozone reacts with the reducing substance, the consumption of ozone is ineffective and the reduction in the number of coliforms cannot be confirmed, but when the reaction between ozone and the reducing substance ends, the reduction in the number of coliforms can be confirmed. It can be confirmed that wasteful consumption (invalid consumption) of ozone occurred. Therefore, in a situation where the reaction between ozone and the reducing substance is completed and the reduction in the number of coliforms can be confirmed, an ozone injection rate that is lower than the discharge standard is set and sterilization is performed.
In the ozone disinfection apparatus according to the first embodiment, the reducing substance automatic measuring device 6 measures the reducing substance contained in the inflowing sewage in real time, and the chemical solution injection device 7 sets the target value to be a reduction target. Feedback control is performed to inject an oxidant other than ozone, and means for reducing the amount of reducing substances before injecting ozone and eliminating the ineffective consumption of ozone is taken.
In this way, by eliminating the ineffective consumption of ozone, as shown in FIG. 8, the reduction of the number of coliforms can be confirmed simultaneously with the ozone injection, and the effect that the disinfection is immediately implemented can be obtained.
For this reason, the capacity of several tens of mg / L, which is the ozone injection rate for the ineffective consumption of ozone, can be reduced, and the use of equipment that is already familiar to the operator ensures workability, reduces equipment costs, and construction It is possible to reduce costs, reduce installation space, secure space for expansion and new installation, and reduce power consumption.
In addition, since it can cope with real-time changes in water quality, it can be sterilized at an appropriate ozone injection rate, and waste of energy and environmental considerations can be realized due to excessive ozone injection.
When untreated inflow sewage, especially heavy rain, flows in at a time in a combined sewage treatment plant where rainwater and sewage are combined and treated on the same treatment line, it cannot be treated with conventional equipment. In some cases, this ozone disinfecting device can perform disinfection at high speed, and even such a case can be dealt with sufficiently.

Embodiment 2. FIG.
FIG. 2 is a system flow diagram of an ozone disinfection apparatus equipped with a flash apparatus according to Embodiment 2 of the present invention. The description of the same or corresponding parts as those in FIG. 1 is omitted.
A second embodiment of the present invention will be described below with reference to FIG.
In FIG. 2, 11, 12, and 13 are each device that constitutes a control unit of a pretreatment device that adjusts the gas injection amount of the exhaust air according to the content of the reducing substance, and 11 is compressed Blow blower that blows air, 12 is a reaction tower that contacts the blown air and inflowing sewage to oxidize reducing substances in the inflowing sewage, and 13 is a target for reducing the measurement value of the automatic measuring device. This is an air volume controller that controls the air volume so that the set value becomes.
Next, the processing operation will be described.
In the second embodiment, the reductive substance automatic measuring device 6 measures the reductive substance contained in the inflowing sewage in real time, and controls the amount of air flow so as to reach the set value that is the target of decrease ( Adjust the amount of air injected into the inflow sewage according to the measured content of reducing substances, and reduce the reducing substances before injecting ozone. Measures are taken to eliminate The effect similar to the effect shown in Embodiment 1 is acquired by eliminating the ineffective consumption of ozone. In addition, the Blow Blower and Beck Reaction Tower are the same equipment that is often used in activated sludge equipment at sewage treatment plants, so it improves the operability of operators and installs equipment. It becomes possible to reduce the space and the equipment cost.
Further, by injecting oxygen or air into the inflowing sewage, it is possible to oxidize the reducing substance and suppress the ineffective consumption of ozone.
If the blower 11 is shared with the ozone source gas supply device 2, the number of equipment can be reduced, and the installation space of equipment can be reduced and the equipment cost can be reduced.

Embodiment 3 FIG.
FIG. 3 is a system flow diagram of an ozone disinfection apparatus equipped with a gas dissolution pump according to Embodiment 3 of the present invention. The description of the same or corresponding parts as those in FIGS. 1 and 2 is omitted.
Hereinafter, a third embodiment of the present invention will be described with reference to FIG.
In FIG. 3, reference numeral 14 denotes a gas dissolution pump that constitutes a part of the control unit of the pretreatment device together with the blower 11 and the air volume controller 13. The gas dissolution pump collects inflow sewage, and the pump blades By making the inflowing sewage contact with the compressed air blown from the exhaust blower 11 using the suction force of the vehicle, the reducing substance in the inflowing sewage reacts with the exhausted air, and the reducing property is reduced. Substances are reduced.
The processing operation is as follows.
Feedback control that measures the reducing substance contained in the inflowing sewage in real time by the reducing substance automatic measuring device 6 and controls the amount of air flow so that the set value becomes the reduction target (contains the measured reducing substance) Adjusting the amount of gas injected into the inflowing sewage according to the amount), reducing the reducing substances in the inflowing sewage before injecting ozone, and eliminating the ineffective consumption of ozone Has been taken.
By eliminating the ineffective consumption of ozone, the same effects as those shown in the first and second embodiments can be obtained.

Embodiment 4 FIG.
FIG. 4 is a system flow diagram of an ozone disinfection apparatus equipped with an injection gas combined type desorption apparatus according to Embodiment 4 of the present invention. Note that the description of the same or corresponding parts as in FIGS.
In the fourth embodiment, a part of the raw material gas is branched and injected into the inflowing sewage in the reaction tower 12 before the injection of ozone to prevent the reaction between ozone and the reducing substance. It is an ozone disinfection device.
The fourth embodiment of the present invention will be described below with reference to FIG.
In FIG. 4, reference numeral 15 denotes a flow rate adjusting valve that constitutes a part of the control unit of the pretreatment device together with the flash reaction tower 12 and the air volume controller 13, and this flow rate adjusting valve generates ozone from the raw material gas supply device 2. It is installed in a branch passage 21 that branches a part of the raw material gas fed to the apparatus 1, and blown into the injection gas combined type pre-reaction tower 12 by this flow rate adjusting valve. Therefore, the raw material gas supply device 2 also serves as the raw material gas supply device to the ozone generator 1 and the flash reactor 12.
The processing operation is as follows.
The reducing substance contained in the inflowing sewage is measured in real time by the reducing substance automatic measuring device 6 and feedback control is performed to control the flow rate by the flow rate adjustment valve 15 so that the set value becomes the target of reduction. Measures have been taken to reduce the amount of reducing substances before ozone injection and eliminate the ineffective consumption of ozone.
By eliminating the ineffective consumption of ozone, the same effects as those shown in the first to third embodiments can be obtained. In addition, the installation facility can also be used as the raw material gas supply device 2 to save installation space and improve maintenance.
In addition, injection by branching of the injection pipe can reduce the installation space of the equipment and reduce the equipment cost.

Embodiment 5 FIG.
FIG. 5 is a system flow diagram of an ozone disinfection apparatus equipped with an injection gas combined type gas dissolution pump according to Embodiment 5 of the present invention. The description of the same or corresponding parts as those in FIGS.
In the fifth embodiment, a part of the raw material gas is branched and injected into the inflowing sewage in the gas dissolution pump 14 before the injection of ozone, thereby preventing the reaction between ozone and the reducing substance. It is an ozone disinfection device.
Hereinafter, a fifth embodiment of the present invention will be described with reference to FIG.
In FIG. 5, reference numeral 15 denotes a flow rate adjusting valve that constitutes a part of the control unit of the pretreatment device together with the air volume controller 13, and this flow rate adjusting valve is fed from the source gas supply device 2 to the ozone generator 1. It is installed in a branch passage 21 that branches a part of the raw material gas, and the flow rate adjusting valve blows air to the injection gas combined type gas dissolution pump 14. Therefore, the source gas supply device 2 also serves as the source gas supply device to the ozone generator 1 and the gas dissolution pump 14.
The processing operation is as follows.
The reducing substance contained in the inflowing sewage is measured in real time by the reducing substance automatic measuring device 6 and feedback control is performed to control the flow rate by the flow rate adjustment valve 15 so that the set value becomes the target of reduction. Measures have been taken to reduce the amount of reducing substances before ozone injection and eliminate the ineffective consumption of ozone.
By eliminating the ineffective consumption of ozone, the same effects as those shown in the first to fourth embodiments can be obtained.

Embodiment 6 FIG.
FIG. 6 is a system flow diagram of an ozone disinfection device equipped with a pH adjustment device according to Embodiment 6 of the present invention. The description of the same or corresponding parts as those in FIGS. 1 to 5 will be omitted.
Hereinafter, a sixth embodiment of the present invention will be described with reference to FIG.
In FIG. 6, 9 and 10 are each apparatus which comprises the control part of the pre-processing apparatus which adjusts pH according to content of the reducing substance in inflow sewage, 9 is reducing the pH of inflow sewage and ozone. PH adjustment device similar to the acid agent used in the sewage treatment plant such as sulfuric acid for maintaining the disinfection effect of the acid, 10 is an acid agent so that the target value of pH is set according to the measurement value of the automatic measurement device PH controller for controlling the injection amount of
The processing operation is as follows.
The reducing substance contained in the inflowing sewage is measured in real time by the reducing substance automatic measuring device 6, and feedback control is performed by injecting the acid agent by the pH adjusting device 9 so that the pH target set value is obtained, thereby disinfecting ozone. Measures are taken to maintain the effect and eliminate the ineffective consumption of ozone.
The effect similar to the effect shown in Embodiment 1 is acquired by eliminating the ineffective consumption of ozone. In addition, the pH adjuster uses an acid agent such as sulfuric acid that is routinely used as a disinfectant at sewage treatment plants to improve the operability of operators, reduce the installation space of equipment, and reduce equipment costs. Can be achieved.

It is a system flow figure of the ozone disinfection apparatus provided with the chemical | medical solution injection device in Embodiment 1 of this invention. It is a system flow figure of the ozone disinfection apparatus provided with the flash apparatus in Embodiment 2 of this invention. It is a system flow figure of the ozone disinfection apparatus provided with the gas dissolution pump in Embodiment 3 of this invention. It is a system flow figure of the ozone disinfection apparatus provided with the injection gas combined type flashing apparatus in Embodiment 4 of this invention. It is a system flow figure of the ozone disinfection apparatus provided with the injection gas combined type gas dissolution pump in Embodiment 5 of this invention. It is a system flow figure of the ozone disinfection apparatus provided with the pH adjustment apparatus in Embodiment 6 of this invention. It is a graph which shows the disinfection effect by the conventional ozone disinfection. It is a graph which shows the disinfection effect by Embodiment 1-6 of this invention. It is a system block diagram which shows the conventional ozone disinfection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ozone generator 2 Raw material gas supply apparatus 3 Ozone dissolution apparatus 4 Power supply apparatus 5 Exhaust ozone decomposition apparatus 6 Reducing substance automatic measurement apparatus 7 Chemical solution injection apparatus 8 Injection controller 9 PH adjustment apparatus 10 PH controller 11 Blow blower 12 Bake reaction Tower 13 Air flow controller 14 Gas dissolution pump 15 Flow control valve.

Claims (6)

An ozone generator for generating ozone for disinfecting the inflowing sewage, a raw material gas supply device for supplying air or oxygen as the raw material gas for the ozone to the ozone generation device, an ozone dissolving apparatus for stirring and mixing the inflowing sewage and the ozone, Real time by automatically measuring iodine consumption in the water quality test method of the inflowing sewage, the ozone decomposing apparatus that treats ozone not absorbed in the inflowing sewage and returns it to the air, and the content of reducing substances in the inflowing sewage The reductive substance automatic measuring unit that measures the amount of reductive substance and the control of reducing the reductive substance in the inflowing sewage before the injection of ozone, controlled according to the content of the reducing substance measured by the reductive substance automatic measuring unit A pretreatment device having a section ,
The inflow sewage flowing into the pretreatment device is untreated inflow sewage in a combined sewage treatment plant where rainwater and sewage are combined and treated in the same treatment line,
An ozone disinfecting apparatus characterized in that the content of reducing substances in the inflowing sewage is measured in real time, the reducing substances are reduced based on the measurement results, and E. coli is reduced by injected ozone .   The control unit of the pre-treatment device includes a pre-reaction tower that pre-treats the reducing substance in the inflowing sewage with the aerated air before the injection of the ozone to prevent the reaction between ozone and the reducing substance. 2. The gas injection amount of the air that has been injected into the inflowing sewage is adjusted according to the content of the reducing substance measured by the reducing substance automatic measuring unit. Ozone disinfection equipment.   The control unit of the pretreatment device includes a gas dissolution pump that pretreats the reducing substance in the inflowing sewage with the aerated air before injecting the ozone and prevents the reaction between ozone and the reducing substance. 2. The gas injection amount of the exhausted air injected into the inflowing sewage is adjusted according to the content of the reducing substance measured by the reducing substance automatic measuring unit. Ozone disinfection device. The control unit of the pretreatment device branches the raw material gas fed from the raw material gas supply device to the ozone generator and sends it to the flash reaction tower, and the inflow sewage before the injection of ozone. The ozone disinfecting apparatus according to claim 2 , wherein the reducing substance contained therein is pretreated to prevent a reaction between ozone and the reducing substance. The control unit of the pretreatment device branches the raw material gas supplied from the raw material gas supply device to the ozone generator and supplies the branched gas to the gas dissolution pump, and before injecting the ozone, The ozone disinfecting apparatus according to claim 3 , wherein the reducing substance is pretreated to prevent a reaction between ozone and the reducing substance.   The pretreatment device includes a pH adjusting device that lowers the pH of the influent sewage and maintains the ozone disinfection effect, and a pH that controls the pH to be a target set value according to the measurement value of the automatic measurement unit. The ozone disinfection device according to claim 1, further comprising a controller.

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