JP4942400B2 - Wastewater treatment method and equipment - Google Patents

Description

The present invention is, for example, relates Bei wastewater wastewater processing method and set of wastewater discharged from aquaculture centers.

  The current situation is that the wastewater discharged from the cultivation fisheries center etc. is discharged into the neighboring ocean without any special treatment. Wastewater discharged from cultivation fisheries centers, etc. has low concentrations of BOD (biochemical oxygen demand), COD (chemical oxygen demand), pollutants, etc., almost colorless low-concentration wastewater, BOD and pollutants There are high-concentration wastewater that is colored and colored. The high-concentration wastewater is mixed and diluted with the low-concentration wastewater and discharged into the ocean.

  Specifically, rotifers that serve as food for larvae that are indispensable for seedling production of marine fish are cultured at the center. The rotifer culture water is discharged as a high-concentration wastewater after being mixed and diluted with low-concentration wastewater. In addition to the rotifer culture, various marine fish are seeded in the aquarium, and a large amount of seawater is supplied to the aquarium and discharged as low-concentration general wastewater. This general wastewater has a lower concentration of BOD, COD, pollutants and the like than the rotifer wastewater.

In general, a device that employs a coagulation sedimentation and flotation separation method is known as a contaminant removal device (see, for example, Patent Document 1).
JP 2005-177681 A

  The cultivation and fishery center requires treatment with low-concentration wastewater and high-concentration wastewater, and a large amount of low-concentration wastewater is discharged compared to high-concentration wastewater. There is a problem of increasing the scale.

  In the case of high-concentration wastewater (such as rotifer wastewater), since it is mixed and diluted with low-concentration wastewater and discharged into the ocean, colored wastewater may flow into the ocean if the proportion is high. From the viewpoint of environmental protection, wastewater treatment at the Cultivation and Fishery Center is an important issue.

  This invention makes it a subject that the processing method according to each waste_water | drain property of a low concentration treated wastewater and a high concentration treated wastewater can be selected.

The present invention has been made in the waste water treatment method and its equipment, waste water treatment method of the present invention, the waste water from the treated waste water generated by the seed production of marine fish, the substance to be removed including contaminants floating The treated waste water that has been removed by the filtering means and removed the substance to be removed is discharged, the substance to be removed is stored in the adjustment tank, and the treatment waste water discharged from the rotifer culture tank is stored in the adjustment tank. Then, after separating the substance to be removed in the adjustment tank with a separation device, the treated waste water from which the substance to be removed has been removed is discharged, and the substance to be removed separated by the separation device is scraped off with the removal device, The substance to be removed supplied from the removing device is stored in the sludge storage tank, the sludge in the sludge storage tank is supplied to the dewatering means, and the water generated when the sludge is separated by the dewatering means is returned to the sludge storage tank. There is.

Treated wastewater generated by seed production of marine fish is discharged after removal in waste water for filtration means substances to be removed. Substances to be removed remaining on the discharge water for filtration means this is stored in the adjustment tank. On the other hand, the wastewater to be treated discharged from the rotifer culture tank is also stored in the adjustment tank. And the to- be-removed substance of the filtration means for drainage is isolate | separated with a separation apparatus with the to-be-removed substance of the wastewater to be processed discharged | emitted from a rotifer culture tank . Moreover, the wastewater to be treated discharged from the rotifer culture tank is discharged as treated wastewater from which the substance to be removed has been removed.
Therefore, the processing method according to each drainage property of the to-be-processed waste_water | drain generate | occur | produced by the seedling production of marine fish and the to- be-processed waste_water | drain discharged | emitted from a rotifer culture tank can be selected. In addition, the treated sludge can be reliably collected, and the waste water discharged from the sludge treatment apparatus can be reprocessed.

Wastewater treatment equipment of the present invention, the raw wastewater generated by seed production of marine fish, and discharge the water for filtration means you remove substances to be removed including contaminants floating, is removed prior Sharing, ABS water for filtration unit An adjustment tank in which the substance to be removed is stored, a pipe into which the treated wastewater discharged from the rotifer culture tank flows into the adjustment tank, a separation device for separating the substance to be removed in the adjustment tank, and the separation a removal device scraping the substances to be removed which is separated in the apparatus, the removing device and the sludge processing device for processing the substance to be removed, which is supplied is provided from the pre-processing processed by Sharing, ABS water for filtration means already drained Is discharged, and the treated wastewater treated by the separation device is discharged, the sludge treatment device includes a sludge storage tank in which a substance to be removed is stored, and sludge in the sludge storage tank through a sludge pump. The dehydration means supplied and before The moisture generated during the separation of the sludge dewatering means is in the fact that a pipe for returning the sludge storage tank. The waste water treatment facility of the present invention can easily carry out the waste water treatment method.

In the wastewater treatment facility comprises a water tank that seawater seedling production the stored and marine fish, raw wastewater that is discharged from the water tank is supplied to the exhaust for water filtration unit, before Sharing, ABS water for filtration unit the filtered-be-removed substance, so as to shift to the adjusting tank, preferably backwash pump is provided for supplying the drainage filtering means filtering seawater or tap water.

In the wastewater treatment facility, the separation device is an electrolytic flotation separation device, and the adjustment tank is provided with a concentration sensor for detecting the concentration of a substance to be removed in the adjustment tank. A control device is provided for controlling the amount of current supplied to the electrolytic levitation separator based on the information. In such a case, an electric current according to the amount of the substance to be removed in the adjustment tank can be supplied to the electrolytic levitation separator, and an efficient operation is possible.

In the wastewater treatment facility, a tank for mixing and aggregating a flocculant with the wastewater to be treated supplied from the adjustment tank is provided, and the separation device removes a substance to be removed in the wastewater to be treated supplied from the tank. It consists of an electrolytic levitation separation device that floats and separates, and the adjustment tank is provided with a concentration sensor for detecting the concentration of the substance to be removed in the adjustment tank, and an electrolytic method based on the information of the concentration sensor A control device for controlling the amount of current supplied to the levitation separator is provided .

In the wastewater treatment facility, since the wastewater to be treated as the liquid to be electrolyzed is seawater, the sterilizing effect of the discharged seawater can be expected by sodium hypochlorite generated by electrolysis. In addition, seawater has more minerals, ions, and impurities than seawater, and has high electrical conductivity and easily flows electricity, so that the electrolytic levitation separator can be operated with less power.

In the wastewater treatment facility, the treated wastewater discharged from the separation device is mixed with the treated wastewater discharged from the wastewater filtering means and discharged .

  In the present invention, a treatment method can be selected in accordance with the drainage properties of the low concentration treated wastewater and the high concentration treated wastewater. Therefore, it is most suitable for facilities such as a cultivation fishery center that uses a large amount of seawater and releases it, for example.

  Embodiments of the present invention will be described with reference to the drawings. In the present embodiment, for example, a wastewater treatment facility that treats high-concentration treated wastewater generated by rotifer culture and low-concentration treated wastewater generated by seed production of various marine fish, for example, in a cultivation fishery center. To do.

  FIG. 1 is a diagram schematically illustrating a wastewater treatment facility according to the present embodiment. As shown in the figure, the wastewater treatment facility 1 is mainly composed of a low concentration wastewater treatment facility 2 and a high concentration wastewater treatment facility 3.

Low concentration wastewater treatment facility 2 includes a filtration device 5 comprises a water tank 6a, a 6b, and a drum filter 7 as waste water for filtration means. The filtration device 5 filters the inflowing seawater with sand and supplies the filtered seawater to the water tanks 6a and 6b. The aquariums 6a and 6b, for example, produce seeds of various marine fish, and exemplify a case where a plurality of fish are arranged. The water tank may be a single body.

  The water tanks 6a, 6b and the drum filter 7 are connected via pipes 9a, 9b, and the general waste water as the low-concentration treated waste water (treated seawater) discharged from the water tanks 6a, 6b is supplied to each drum. It is supplied to the filter 7. The general waste water has a COD of about 10 mg / liter, and pollutants (substances to be removed) such as marine fish dung, bait, and garbage are mixed as suspended matter (SS).

  A pair (two) of drum filters 7 are provided for each of the water tanks 6a and 6b, and one of them can be used alternatively. The drum filter 7 includes a filter (not shown) that removes SS from the general waste water, and the low-concentration general waste water from which SS has been removed by this filter is discharged to the ocean via the discharge pipes 10 and 11. . The general waste water from which SS has been removed has a low concentration of COD and BOD, and is almost colorless.

  The filtration device 5 is provided with a backwash water storage tank 12, and SS attached to sand obtained by filtering seawater is stored in the backwash water storage tank 12 together with seawater in the existing filtration tank 12 a by a pump 13. Is done. The backwash pump 14a provided in the backwash water storage tank 12 and the pipe 9a are connected by a branch pipe 14, and the water stored in the backwash water storage tank 12 flows through the branch pipe 14 and the pipe 9a. It flows into the drum filter 7.

  The high-concentration wastewater treatment facility 3 includes an adjustment tank 15, a reaction tank 16, a coagulation tank 17, a pH adjuster tank 18, a first coagulant tank 19, and a second coagulant tank (polymer flocculant tank) 20. And an electrolytic levitation separation device 21 as a separation device, an SS removal device 22, and a sludge treatment device 23.

  The adjustment tank 15 is connected to the drum filter 7 via pipes 25a and 25b. Specifically, the drum filter 7 on the water tank 6a side is connected to the pipe 25a, and the drum filter 7 on the water tank 6b side is connected to the pipe 25b.

  The drum filter 7 is connected to a storage tank 27 in which filtered water such as filtered seawater or clean water is stored, and a pipe 28 in which a backwash pump 29 is interposed. The backwash pump 29 supplies the filtered seawater in the storage tank 27 to the drum filter 7 as appropriate. The filtered seawater flows in the opposite direction to the filter filtration of the drum filter 7 to remove SS adhering to the filter, and this SS flows into the adjustment tank 15 through the pipes 25a and 25b and is stored. It is like that.

  The wastewater to be treated (rotifer culture wastewater) containing high-concentration floating pollutant discharged from the rotifer culture tank 30 for cultivating the rotifer flows through the pipe 31 and is stored in the adjustment tank 15. The rotifer culture wastewater has a higher concentration of COD, contaminants, etc. than the general wastewater, and is discharged from the rotifer culture tank 30 in a colored state. A drainage transfer pump 32 is installed in the adjustment tank 15, and the drainage transfer pump 32 supplies the high-concentration treated wastewater in the adjustment tank 15 to the reaction tank 16 via the pipe 33.

  A propeller 35 that is rotated by a motor is provided in the reaction tank 16. Further, for example, polyaluminum chloride (PAC) is injected into the reaction tank 16 from the first flocculant tank 19, and a pH adjuster such as sodium hydroxide is injected from the pH adjuster tank 18. The wastewater to be treated stirred by the propeller 35 becomes neutral, and the fine SS is agglomerated to a core size.

  The wastewater to be treated in which the SS aggregated in the reaction tank 16 is mixed is transferred to the aggregation tank 17. A polymer flocculant is injected into the flocculant tank 17 from the second flocculant tank 20. The wastewater to be treated in the coagulation tank 17 is agitated by a propeller 36 that is rotated by a motor. Note that the rotation speed of the propeller 36 in the aggregation tank 17 is set to be slower than the rotation speed of the propeller 35 in the reaction tank 16. Thus, by setting the rotation speed of the propeller 35 in the reaction tank 16 faster, the flocculant and the pH adjuster are rapidly stirred, and by setting the rotation speed of the propeller 36 in the aggregation tank 17 slower, the SS Can be grown to a predetermined size.

  The electrolytic levitation separation device 21 is mainly composed of an electrolytic levitation tank 40 whose diameter is expanded upward, and an electrode 41 provided at the lower part of the electrolytic levitation tank 40. The wastewater to be treated in the aggregation tank 17 is supplied to the lower part of the electrolytic levitation tank 40 through a pipe 43. The electrode 41 electrolyzes the wastewater to be treated and generates fine gas composed of bubbles of oxygen gas and hydrogen gas.

  The amount of current supplied to the electrode 41 is controlled by the control device 44. That is, the adjustment tank 15 is provided with a concentration sensor 37 such as a concentration meter that detects the SS concentration contained in the wastewater to be treated in the tank. The control device 44 controls the amount of current supplied to the electrode 41 based on information from the concentration sensor 37. Since the amount of gas generated is proportional to the current density supplied to the electrode 41, for example, when the SS concentration of the adjustment tank 15 is high, the control device 44 increases the current supply amount to the electrode 41, and conversely SS. When the concentration is low, the amount of current supplied to the electrode 41 is decreased.

  The SS removing device 22 is arranged in the upper part of the electrolytic levitation tank 40, and automatically collects flocs (SS attached to the gas) that have been levitated together with fine gas and removes SS. For example, the flock is scraped off. A device having a rotating endless body. The treated waste water from which SS has been removed passes through the water level adjustment pipe 45 and is discharged through the discharge pipe 46. The discharge pipe 46 is connected to the discharge pipe 10 of the low-concentration waste water treatment facility 2, and the treated waste water flowing through the discharge pipe 46 is mixed with a large amount of treated waste water flowing through the discharge pipe 10 and discharged. It has come to be.

  The sludge treatment device 23 performs sludge treatment on the SS separated and recovered by the SS removal device 22, and includes a sludge storage tank 47 for storing sludge discharged from the SS removal device 22 and a centrifuge 50. . The sludge storage tank 47 is connected to a centrifuge 50 as a dehydrating means by a pipe 48 in which a sludge pump 49 is interposed. The centrifuge 50 dehydrates the sludge stored in the sludge storage tank 47 and removes moisture from the sludge. Sludge whose volume has been reduced is treated as industrial waste.

  The centrifugal separator 50 is connected to a return pipe 51 that returns moisture to the sludge storage tank 47. The sludge pump 49 is connected to a return pipe 52 that returns the stored liquid in the sludge storage tank 47 to the adjustment tank 15. 55 and 56 are switching valves. For the dewatering of sludge, an ordinary dehydrator or the like can be used in addition to the centrifugal separation, and it is not particularly limited.

  Next, a wastewater treatment method in the wastewater treatment facility having the above configuration will be described with reference to FIG.

  First, the low concentration waste water treatment method will be described. A large amount of seawater flows into the filtration device 5, and after being filtered by the filtration device 5, is supplied to the respective water tanks 6 a and 6 b. The low-concentration general waste water discharged from the water tanks 6a and 6b is supplied to the drum filter 7 through the pipes 9a and 9b. When the general waste water passes through the drum filter 7, SS in the general waste water adheres to the filter and SS is removed. The general waste water that has passed through the drum filter 7 is discharged into the ocean through the discharge pipes 10 and 11 as almost colorless treated waste water.

  Since each water tank 6a, 6b is provided with a pair of drum filters 7, even when one drum filter 7 is used, the other unused drum filter 7 can be washed. Even if one drum filter 7 breaks down, the other drum filter 7 can continue the waste water treatment. That is, the filtered seawater in the storage tank 27 is supplied to the other drum filter 7 to remove SS adhering to the filter. The filtered seawater or clean water flows through the pipes 25 a and 25 b together with the removed SS and is stored in the adjustment tank 15.

  Moreover, the pollutant etc. which adhered to the filtration apparatus 5 can also be removed by making the seawater which flows into the filtration apparatus 5 flow into the backwash water storage tank 12 with the pump 13. FIG. The seawater stored in the backwash water storage tank 12 flows through the branch pipe 14 and the pipe 9a by the backwash pump 14a, and is discharged after being filtered by the drum filter 7. In addition, it is the same as that of the said general waste water that the pollutant etc. which adhered to this drum filter 7 are supplied to the adjustment tank 15.

  Next, the high concentration waste water treatment method will be described. The rotifer drainage discharged from the rotifer culture tank 30 flows through the pipe 31 and is stored in the adjustment tank 15. The wastewater transfer pump 32 supplies seawater to be treated, which is wastewater to be treated at a high concentration in the adjustment tank 15, to the reaction tank 16 via the pipe 33. In the reaction tank 16 and the coagulation tank 17, SS of the wastewater to be treated is aggregated, flows through the pipe 43, and is supplied to the lower part of the electrolytic levitation tank 40. The amount of current supplied to the electrode 41 is controlled by the control device 44, and the treated wastewater is electrolyzed to generate a fine gas composed of oxygen gas and hydrogen gas bubbles. SS becomes a flock and rises with bubbles.

  Then, the SS that has surfaced is recovered and removed by the SS removing device 22. The treated waste water from which SS has been removed passes through the water level adjustment pipe 45 and is discharged through the discharge pipe 46. Such treated wastewater is almost colorless and low-concentration wastewater, but it is agglomerated if the temperature of the treated wastewater is high as in summer or if SS is left in the electrolytic levitation tank 40 for a long period of time. There is a risk that the BOD component and the COD component are decomposed from the SS and dissolved into the wastewater to be treated. In such a case, the concentration of the treated wastewater becomes high, but the treated wastewater flowing through the discharge pipe 46 is mixed and diluted with a large amount of treated wastewater having a low concentration flowing through the discharge pipe 10 and discharged.

  The SS recovered by the SS removing device 22 is transferred to the sludge treatment device 23. SS is stored as sludge in the sludge storage tank 47, and the sludge in the sludge storage tank 47 is dehydrated by the centrifuge 50. The dewatered sludge is discarded as industrial waste. On the other hand, the water discharged from the centrifuge 50 is returned to the sludge storage tank 47. The stored effluent in the sludge storage tank 47 flows into the adjustment tank 15 via the return pipe 52 by the sludge pump 49.

  As described above, the wastewater treatment facility of the present embodiment can remove SS components in the low-concentration wastewater treatment facility 2 and the high-concentration wastewater treatment facility 3 according to the amount of wastewater to be treated. As a result, a large amount of general wastewater is treated in large quantities by passing through the drum filter 7, and the rotifer culture wastewater is treated with the electrolytic levitation separator 21 and the like together with SS removed from the general wastewater. With the treatment method and the high-concentration wastewater treatment method, each wastewater can be treated at the same time, BOD, COD, nitrogen, phosphorus, etc. caused by SS can be removed, and the environmental load of the discharged water can be reduced.

  The electrolytic levitation system with electrolytic levitation separator suitable for high-concentration wastewater treatment is expected to have a bactericidal effect on the discharged seawater due to sodium hypochlorite generated by electrolysis because the liquid to be electrolyzed is seawater. . In addition, seawater has more minerals, ions, and impurities than seawater, and has high electrical conductivity and easily flows electricity, so that the electrolytic levitation separator can be operated with less power. In addition, it is also possible to sterilize the processed waste water which flows through the discharge pipes 10 and 11 of the low concentration waste water treatment facility 2 with a sterilizer.

  Separation devices are not limited to those of electrolytic levitation method, but levitation method has a smaller installation area of equipment and can be unitized compared to agglomeration method, minimizing civil engineering work. it can. In particular, the Cultivation and Fishery Center is close to the sea, so there are advantages to having less civil engineering work. Moreover, since the treated wastewater flowing through the discharge pipe 46 is mixed and diluted with a large amount of treated wastewater having a low concentration flowing through the discharge pipe 10, the seawater around the discharge can be prevented from being contaminated, and the clean discharge vicinity. There is also an advantage that seawater can be used.

  The present invention is not limited to the embodiment described above. For example, as shown in phantom lines in FIG. 1, the second flocculant tank 20 and the electrolytic levitation tank 40 are connected by a pipe 53, and the flocculant in the second flocculant tank 20 is directly supplied to the electrolytic levitation tank 40. You may make it do. In such a case, there is an advantage that the flocculant is agitated by bubbles generated by electrolysis of seawater to be treated at a high concentration, and the agglomeration tank 17 is not required.

It is the schematic of the waste water treatment facility which shows one embodiment which concerns on this invention.

Explanation of symbols

1 wastewater treatment facility 2 low concentration wastewater treatment facility 3 high-concentration wastewater treatment facility 5 filtration device 6a, 6b water tub 7 drum filter (waste water for filtration means)
9 Pipe 10 Drain pipe 11 Drain pipe 12 Backwash water storage tank 14a Backwash pump 15 Adjustment tank 16 Reaction tank (tank)
17 Coagulation tank 21 Electrolytic floating separator (separator)
22 SS removal device (removal device)
23 Sludge treatment device 29 Backwash pump 30 Rotifer culture tank 31 Piping 37 Concentration sensor 44 Control device 46 Discharge pipe 47 Sludge storage tank 49 Sludge pump 50 Dehydration means (centrifugal separator)
52 Return piping (Piping)

Claims (6)

From the treated wastewater generated by the production of seedlings of marine fish, the to-be-removed material containing floating pollutants is removed by a filtering means for drainage, and the treated wastewater from which the to-be-removed material has been removed is discharged, and the to-be-removed material is Stored in the adjustment tank,
In the adjustment tank, the treated wastewater discharged from the rotifer culture tank is stored,
After separating the substance to be removed in the adjustment tank with a separator, the treated waste water from which the substance to be removed has been removed is discharged, and the substance to be removed separated by the separator is scraped with the remover,
The substance to be removed supplied from the removal device is stored in a sludge storage tank,
Supplying the sludge in the sludge storage tank to the dewatering means;
A wastewater treatment method characterized by returning water generated when the sludge is separated by the dewatering means to the sludge storage tank. Drainage filtering means for removing substances to be removed, including floating pollutants, from the wastewater to be treated generated by seed production of marine fish;
A regulating tank in which the substance to be removed removed by the drainage filtering means is stored;
A pipe into which the treated wastewater discharged from the rotifer culture tank flows into the adjustment tank,
A separation device for separating the substance to be removed in the adjustment tank ;
A removal device for scraping off a substance to be removed separated by the separation device;
A sludge treatment device for treating the material to be removed supplied from the removal device, and
The treated wastewater treated by the drainage filtering means is discharged, and the treated wastewater treated by the separator is discharged,
The sludge treatment apparatus includes a sludge storage tank in which a substance to be removed is stored, a dewatering means in which the sludge in the sludge storage tank is supplied via a sludge pump, and moisture generated when the sludge is separated by the dewatering means. A wastewater treatment facility comprising a pipe for returning the wastewater to the sludge storage tank.   The wastewater treatment facility according to claim 2, further comprising a water tank for storing seawater and producing seedlings of marine fish, and treated wastewater discharged from the water tank is supplied to the drainage filtering means, A wastewater treatment facility comprising a backwash pump for supplying filtered seawater or clean water to the drainage filtration means so that the substance to be removed filtered by the filtration means is transferred to the adjustment tank. The wastewater treatment facility according to claim 2 or 3 , wherein the separation device comprises an electrolytic levitation separation device, and the adjustment tank includes a concentration sensor for detecting a concentration of a substance to be removed in the adjustment tank. And a controller for controlling the amount of current supplied to the electrolytic levitation separator based on the information of the concentration sensor. The wastewater treatment facility according to claim 2 or 3 , wherein a tank for mixing and stirring the coagulant in the wastewater to be treated supplied from the adjustment tank is provided, and the separator is a wastewater treatment apparatus supplied from the tank. It consists of an electrolytic levitation separator that floats and separates the substance to be removed in the treated wastewater, and the adjustment tank is provided with a concentration sensor for detecting the concentration of the substance to be removed in the adjustment tank, and the concentration A wastewater treatment facility characterized in that a control device is provided for controlling the amount of current supplied to the electrolytic levitation separator based on sensor information. The wastewater treatment facility according to claim 2 or 3 , wherein the treated wastewater discharged from the separator is mixed with the treated wastewater discharged from the wastewater filtering means and discharged. Wastewater treatment facility.

Images