JP5358495B2 - Waste water management device and waste water management method - Google Patents

Description

  The present invention relates to a wastewater management apparatus and a wastewater management method for measuring the COD (chemical oxygen demand) of wastewater and managing the possibility of discharge to the outside.

  For example, in power plants, general wastewater used in power generation facilities, domestic wastewater used in toilets and kitchens, NS decomposition tanks that treat nitrogen compounds, sulfur compounds, etc., and pH adjustment tanks that adjust pH The COD adsorption tower that reduces COD is used to discharge it into rivers and the sea. In addition, COD of wastewater that is allowed to be discharged and total nitrogen, total phosphorus, etc. contained in wastewater are regulated or stipulated by agreements, etc., so COD etc. of wastewater after treatment is measured and COD is regulated When the value is larger than the value, the discharge of the waste water is stopped (for example, see Patent Document 1). That is, in the case of COD, for example, the UV absorbance of waste water is measured by a UV meter, and the load amount calculator calculates the COD based on the measurement signal from the UV meter and the output signal from the flow meter. When the calculated COD is larger than the regulation value, the discharge valve is closed to stop the discharge of the waste water.

JP 2009-165911 A

  As described above, conventionally, only the upper limit of the COD is monitored, and the discharge of the waste water is stopped only when the COD is larger than the upper limit (regulation value). That is, even if an extremely low value was measured as COD, the discharge of waste water was not stopped. By the way, when a failure of the UV meter or the load amount calculator or a measurement failure due to an adhering matter (measurement abnormality) occurs, an extremely low value (zero value) may be measured as COD. However, in the conventional wastewater management, even if an extremely low value is measured as the COD, the wastewater continues to be discharged because the COD is below the regulation value. For this reason, even if there is drainage in which the actual OCD is larger than the regulation value, such as during a failure of the UV meter or the load amount calculator, the measured value is less than the regulation value, so that the drainage is larger than the regulation value. The present inventor has come to think that there is a risk of being discharged.

  Accordingly, an object of the present invention is to provide a drainage management apparatus and a drainage management method capable of more reliably preventing discharge of drainage having a COD larger than a regulation value to the outside.

In order to achieve the above object, the invention according to claim 1 is directed to a waste water after processing a general waste water used in a power generation facility in a power plant by a general waste water treatment device, and a life from a toilet or a kitchen in the power plant. The wastewater that has been treated with the domestic wastewater treatment device is mixed and stored in the wastewater mixing tank, and the discharge of the wastewater from the wastewater mixing tank is managed, and the wastewater treated by the general wastewater treatment device wherein a common waste water treatment can be a wastewater management system reflux apparatus, a measuring means for measuring the chemical oxygen demand of the waste water of the waste water mixture bath, based on the measurement values by the measuring means, the drainage mix Determining means for determining whether or not the drainage in the tank can be discharged to the outside, and the determination means includes a first comparator for comparing and determining whether or not the measured value is equal to or greater than a predetermined upper limit value. , The measured value is predetermined And whether the comparison determines the second comparator or is below limit value, the measurement value and a third comparator comparing determines higher or not than a predetermined value, the measurement value is given When it is determined that the discharge from the waste water mixing tank is not possible when the value is equal to or higher than the upper limit and equal to or lower than the predetermined lower limit, and the measured value is compared and determined to be higher than the predetermined value by the third comparator to be determined to require an alarm, it is wastewater management apparatus according to claim. Here, the chemical oxygen demand (COD) includes biodegradable organic matter (BOD).

  According to this invention, when the COD of the wastewater is measured by the measuring means and the measured value is equal to or greater than the predetermined upper limit value, that is, when the COD is larger than the regulation value (or its management value), the wastewater is discharged by the determining means. It is determined that it is not possible to discharge to the outside. In addition, when the measurement value by the measurement unit is equal to or less than the predetermined lower limit value, that is, when it is estimated that the measurement is abnormal by the measurement unit, the determination unit determines that the discharge of the waste water is impossible.

Invention according to claim 2, in wastewater management apparatus according to claim 1, wherein the predetermined lower limit value, based on past chemical oxygen demand of the waste water, the possibility of abnormal measurement by the measuring means It is set to the value estimated that there exists.

The invention according to claim 3 is a domestic wastewater treatment device for treating wastewater after treatment of general wastewater used in power generation equipment at a power plant with a general waste water treatment device and living waste water from a toilet or kitchen at the power plant. The treated waste water is mixed and stored in the waste water mixing tank, and the waste water from the waste water mixing tank is discharged and the waste water treated by the general waste water treatment apparatus is returned to the general waste water treatment apparatus. A wastewater management method that is possible, the chemical oxygen demand of wastewater in the wastewater mixing tank is measured by a measuring means, and based on the measured value by the measuring means , the outside of the wastewater in the wastewater mixing tank The determination means determines whether or not discharge is possible, and the determination means compares a first comparator for determining whether or not the measured value is equal to or higher than a predetermined upper limit value, and the measured value is equal to or lower than a predetermined lower limit value. Whether or not A second comparator determines compare the measured value and a third comparator comparing determines whether higher than a predetermined value, if the measurement value is equal to or larger than a predetermined upper limit value and a predetermined lower limit If the value below the drainage the discharge from the mixing tank is determined impossible, if the measured value in said third comparator is compared determined to be higher than the predetermined value, it determines to require an alarm, It is the wastewater management method characterized by this.

According to the first and third aspects of the invention, not only when the COD of the wastewater is larger than the regulation value, but also when the measured value is equal to or lower than the predetermined lower limit and is estimated to be abnormal, It is determined that discharge is not possible. For this reason, even if the measurement means malfunction or measurement failure occurs and the measured value is smaller than the regulated value, the wastewater whose actual OCD is larger than the regulated value is discharged during that time. Can be avoided. In this way, it is possible to more reliably prevent the discharge of waste water having a COD larger than the regulation value to the outside.

According to the first aspect of the present invention, since it is determined that an alarm is required , it is possible to notify a manager or the like of a measurement abnormality by the alarm and promote a prompt and appropriate response.

According to the second aspect of the present invention, the predetermined lower limit value is set to a value estimated that there is a possibility of measurement abnormality based on the past COD of the drainage. For example, by setting the upper limit of a value that could not be a past actual COD value as a predetermined lower limit, the predetermined lower limit becomes an appropriate value as a value for detecting and monitoring a measurement abnormality. As a result, it becomes possible to more reliably prevent the discharge of waste water having a COD larger than the regulation value to the outside.

1 is a schematic block diagram showing a wastewater management apparatus according to an embodiment of the present invention. It is a block diagram which shows the peripheral installation by which the waste_water | drain management apparatus of FIG. 1 is arrange | positioned.

  The present invention will be described below based on the illustrated embodiments.

  FIG. 1 is a schematic block diagram showing a wastewater management apparatus 1 according to an embodiment of the present invention. This wastewater management device 1 is a device that measures the COD (chemical oxygen demand) of wastewater and manages whether or not it can be discharged to the outside, and mainly includes a measuring device (measuring means) 2 and a determination device (determination) Means) 3. Here, an explanation will be given taking as an example that the wastewater to be managed is wastewater in a power plant.

  The measuring device 2 is a device that measures the COD of waste water, and includes a UV meter 21 and a load amount calculator 22. The UV meter 21 is a meter that measures the ultraviolet absorbance of the waste water, and the load calculator 22 is a measurement signal from the UV meter 21 and an output signal from a flow meter (not shown) that measures the flow rate of the waste water. Is a calculator that calculates (converts) COD based on the above. Here, instead of the UV meter 21, a COD meter that measures the amount (COD) of a substance that is easily oxidized in waste water consumes an oxidizing agent may be provided.

  The determiner 3 is a circuit / algorithm that determines whether or not the drainage can be discharged to the outside based on the measurement value of the measuring device 2. That is, comparators (Monitor Switches) 31 to 33 are provided. In the first comparator 31, whether or not the measured value is “COD abnormally high”, specifically, 13.5 mg / l (predetermined upper limit). Value) or more. Further, in the second comparator 32, it is compared and determined whether or not the measured value is “COD abnormally low”, specifically, whether or not it is 0.4 mg / l (predetermined lower limit value) or less. . Further, the third comparator 33 compares and determines whether or not the measured value is “COD high”, specifically, whether or not it is 12.0 mg / l or more.

  When the first comparator 31 compares and determines “COD abnormally high”, it is determined that the discharge of the wastewater to the outside is impossible (discharge stop), and the second comparator 32 determines “COD abnormally low”. If it is compared and determined, it is determined that the discharge of the wastewater to the outside is impossible, and it is determined that an alarm is required. Further, when the third comparator 33 compares and determines “COD high”, it is determined that an alarm is required.

  Here, the threshold values 13.5 mg / l and 12.0 mg / l are set as follows. That is, when the maximum COD (regulated value) of the wastewater allowed to be discharged to the outside is 15.0 mg / l, 13.5 mg / l, which is 90% of the maximum COD, is considered in view of safety (safety factor). If l is the upper limit value (regulatory control value), and if it is equal to or greater than this upper limit value, it is set as “undischargeable”. Further, 12.0 mg / l, which is 80% of the maximum COD, is set as an alarm value.

  Furthermore, the predetermined lower limit value of 0.4 mg / l is set to a value that is estimated to be possibly measured abnormally by the measuring device 2 based on the past COD of the drainage. That is, the COD actual measurement value of drainage in a past period (for example, one month) is totaled to grasp the distribution state of COD. Then, a value that is impossible as an actual COD, a suspicious value, or a value with a very low measurement frequency is set as a value that is estimated to have a possibility of measurement abnormality. For example, according to the past COD distribution state, when the measured value of COD is almost 0.5 mg / l or more, the upper limit of the value estimated to be possibly abnormal measurement is set to 0.4 mg / l, This value is set as a predetermined lower limit value. As such a setting method, a statistical method such as 3 sigma or 6 sigma may be used, and when a measurement abnormality needs to be discovered early, a predetermined lower limit value is set according to the purpose. It may be set larger.

  Further, the determination device 3 is connected to the checking SW 4, and when the checking SW 4 is turned on, the determination device 3 determines “discharging stop” and “alarm required”. Furthermore, the drainage management device 1 is configured to transmit an open / close signal, an alarm signal, and the like to valves 110, 111, an alarm device 108, and the like, which will be described later, based on the determination result by the determiner 3.

  Such a waste water management apparatus 1 is disposed in a waste water treatment system as shown in FIG. 2, for example. In this wastewater treatment system, the general wastewater used in the power generation facility is sent to the general water receiving tank 101, and the wastewater in the general water receiving tank 101 is drained by the general wastewater treatment apparatus 102. Similarly, domestic wastewater from a toilet or a kitchen is sent to the living water receiving tank 103, and the wastewater in the living water receiving tank 103 is drained by the domestic wastewater treatment apparatus 104. Here, the waste water treatment devices 102 and 104 are treatment devices according to the type of waste water, the purpose of treatment, and the like, for example, an NS decomposition tank for treating nitrogen compounds, sulfur compounds, etc., a pH adjusting tank for adjusting pH. , A sedimentation tank that settles and removes heavy metals, and a filter that removes fine substances.

  Next, the wastewater treated by the general wastewater treatment device 102 can be returned to the general wastewater treatment device 102 via the first valve 110 by the first pump 106 and mixed with the wastewater via the second valve 111. It is sent to the tank 105. Similarly, the wastewater treated by the domestic wastewater treatment device 104 is sent to the wastewater mixing tank 105 by the second pump 107. Further, the waste water from the waste water mixing tank 105 is discharged to the outside such as a river or the sea.

  The waste water mixing tank 105, the valves 110 and 111, and the second pump 107 are connected to the waste water management apparatus 1, and the COD of the waste water in the waste water mixing tank 105 is measured by the measuring device 2, and the valves 110 and 111 are also measured. A control signal is sent from the drainage management device 1 to the second pump 107. Further, an alarm device 108 is connected to the drainage management device 1, and an alarm signal is sent from the drainage management device 1 to the alarm device 108. Here, the valves 110 and 111 and the second pump 107 have a function of opening and closing based on the received control signal, and the alarm device 108 generates an alarm sound based on the received alarm signal while generating an alarm sound. It has a function to blink.

  Next, the operation of the wastewater management apparatus 1 having such a configuration and the wastewater management method according to the embodiment of the present invention will be described.

  First, in normal times, the pumps 106 and 107 are operated, the first valve 110 is closed, and the second valve 111 is opened. In this state, the general wastewater used in the power generation facility is drained by the general wastewater treatment device 102 via the general water receiving tank 101 and stored in the wastewater mixing tank 105, and from a toilet or a kitchen. The domestic wastewater is drained by the domestic wastewater treatment device 104 via the living water receiving tank 103 and stored in the drainage mixing tank 105. And the waste_water | drain in the waste_water | drain mixing tank 105 is discharged outside. In such a state, the COD of the wastewater in the wastewater mixing tank 105 is periodically measured (for example, every hour) by the measuring device 2 of the wastewater management device 1, and the wastewater is discharged to the outside based on the measured value. Whether or not discharge is possible is determined by the determiner 3.

  For example, when the measured value is 12.0 mg / l or more and less than 13.5 mg / l, it is determined that an alarm is required as “COD high”. Then, an alarm signal for issuing an alarm is transmitted from the drainage management device 1 to the alarm device 108, and an alarm sound is generated in response to the alarm signal. Subsequently, when the measured value is 13.5 mg / l or more, it is determined that the discharge of the wastewater to the outside is impossible as “COD abnormally high”. Then, the drainage management device 1 transmits a stop command to the second pump 107, a valve opening command to the first valve 110, and a valve closing command opening / closing signal to the second valve 111. Thereby, the inflow of the waste water from the waste water treatment apparatuses 102 and 104 to the waste water mixing tank 105 is stopped, and the discharge of the waste water is stopped.

  On the other hand, when the measured value is 0.4 mg / l or less, it is determined that “COD abnormality is low” and the discharge of the wastewater to the outside is impossible and an alarm is required. Then, the drainage management device 1 transmits a stop command to the second pump 107, a valve opening command to the first valve 110, and a valve closing command opening / closing signal to the second valve 111. Thereby, the inflow of the waste water from the waste water treatment apparatuses 102 and 104 to the waste water mixing tank 105 is stopped, and the discharge of the waste water is stopped. At the same time, an alarm signal is transmitted from the drainage management device 1 to the alarm device 108, and an alarm sound is emitted from the alarm device 108. In addition, when checking the equipment, by turning on SW4 during the check, it is determined by the determiner 3 that “discharge stop” and “alarm required”, and the discharge of the drainage to the outside is stopped, and the alarm device An alarm sound or the like is emitted from 108.

  As described above, according to the wastewater management apparatus 1 and the wastewater management method, not only when the COD of the wastewater is equal to or higher than the predetermined upper limit value, but the measured value is equal to or lower than the predetermined lower limit value, and it is estimated that the measurement is abnormal. Even in this case, it is determined by the determiner 3 that the discharge of the waste water is impossible. For this reason, even if it is a case where a failure of the measuring apparatus 2 or a measurement failure occurs, a situation in which wastewater whose OCD is larger than the regulation value (15.0 mg / l) is discharged in the meantime is avoided. Can do. In this way, it is possible to more reliably prevent the discharge of waste water having a COD larger than the regulation value to the outside.

  Moreover, since the predetermined lower limit value is set to a value that is estimated to have a measurement abnormality based on the past COD of the waste water, the predetermined lower limit value is used as a value for detecting and monitoring the measurement abnormality. Is optimized. As a result, it becomes possible to more reliably prevent the discharge of waste water having a COD larger than the regulation value to the outside. In addition, if the measured value of COD is less than or equal to the predetermined lower limit value and is estimated to be abnormal, an alarm is issued, so the administrator is notified of the abnormal measurement by the alarm and promotes prompt and appropriate response. It becomes possible to do.

  Although the embodiment of the present invention has been described above, the specific configuration is not limited to the above embodiment, and even if there is a design change or the like without departing from the gist of the present invention, Included in the invention. For example, in the above embodiment, the wastewater management device 1 is integrally provided with the measuring device 2 and the determination device 3, but the determination device is a control device that controls the valves 110, 111, the second pump 107, and the like. 3, the measurement value may be transmitted from the measurement device 2 to the control device, and the determination unit 3 may determine the measurement value. Further, although the alarm device 108 generates an alarm sound, it may be notified to an administrator at a remote location.

1 Wastewater management device 2 Measuring device (measuring means)
21 UV meter 22 Load calculator 3 Judgment device (judgment means)
31-33 comparator

Claims (3)

Mixing the wastewater after processing the general wastewater used in the power generation facilities at the power plant with the general wastewater treatment device and the wastewater after treating the domestic wastewater from the toilet and kitchen at the power plant with the domestic wastewater treatment device A wastewater management apparatus that stores the wastewater in the wastewater mixing tank and discharges the wastewater from the wastewater mixing tank, and the wastewater treated by the general wastewater treatment apparatus can be returned to the general wastewater treatment apparatus. ,
Measuring means for measuring the chemical oxygen demand of the wastewater in the wastewater mixing tank ;
A determination unit that determines whether or not the drainage of the wastewater in the wastewater mixing tank is allowed to be discharged to the outside based on a measurement value by the measurement unit;
The determination means compares and determines whether or not the measured value is equal to or greater than a predetermined upper limit value and a first comparator that determines whether or not the measured value is equal to or smaller than a predetermined lower limit value. A comparator and a third comparator for determining whether or not the measured value is higher than a predetermined value, and when the measured value is not less than a predetermined upper limit value and not more than a predetermined lower limit value, waste water wherein the waste water of the effluent from the mixing tank is determined impossible, if the said measured value with a third comparator comparing determined to be higher than the predetermined value, determines to require an alarm, characterized in that Management device. Claims wherein the predetermined lower limit value, on the basis of the past chemical oxygen demand of the waste water, the is set to a value which is estimated that there is a possibility of measurement abnormality by measuring means, characterized in that wastewater management device according to 1. Mixing the wastewater after processing the general wastewater used in the power generation facilities at the power plant with the general wastewater treatment device and the wastewater after treating the domestic wastewater from the toilet and kitchen at the power plant with the domestic wastewater treatment device A wastewater management method in which the wastewater from the wastewater mixing tank is discharged and managed, and the wastewater treated by the general wastewater treatment device can be returned to the general wastewater treatment device. ,
Measure the chemical oxygen demand of the wastewater in the wastewater mixing tank by measuring means,
Based on the measurement value by the measurement means , the determination means determines whether or not the waste water in the waste water mixing tank can be discharged to the outside,
The determination means compares and determines whether or not the measured value is equal to or greater than a predetermined upper limit value and a first comparator that determines whether or not the measured value is equal to or smaller than a predetermined lower limit value. A comparator and a third comparator for determining whether or not the measured value is higher than a predetermined value, and when the measured value is not less than a predetermined upper limit value and not more than a predetermined lower limit value, waste water wherein the waste water of the effluent from the mixing tank is determined impossible, if the said measured value with a third comparator comparing determined to be higher than the predetermined value, determines to require an alarm, characterized in that Management method.

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