JPH07275894A - Wastewater treatment - Google Patents

Abstract

PURPOSE:To oxidize, reduce and efficiently remove harmful substances by heating wastewater containing a large amount of organic substances and having high salt concentration to evaporate the wastewater after solid-liquid separation, condensing the vapor to extract fine suspended substances and salts from the condensate, and radiating ozone to the filtered liquid. CONSTITUTION:After solid-liquid separation of wastewater from a water tank 1 into solid matter and a separated liquid by solid-liquid separating apparatuses 3, 7, the separated liquid (filtered liquid) is heated by a preheating apparatus 25 and a heater 26 and then boiled by a steam heating apparatus 28 after the liquid passes an evaporating can 27. Then, the concentrated filtered liquid obtained in the crystallizing can 29 is separated into a filtered liquid and crystalline substances by a cyclone 30 and the crystallized substances are collected by a crystalline substance separating apparatus 31. Meanwhile, the evaporated filtered liquid is gas-liquid separated by a mist separator 32, led to the steam heating apparatus 28, the heater 26, and the preheating apparatus 25 to stepwise lower the temperature, and after the temperature is lowered, the liquid is stored in a relay tank 34. The resultant filtered liquid is introduced into a reaction tower 35, sprayed in superfine particle state, and irradiated with ultraviolet rays 36 to oxidoreduce suspended substances and malodorous substances and remove them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water treatment facility, and relates to a method for treating wastewater containing a large amount of organic substances and having a high salt concentration.

[0002]

2. Description of the Related Art Wastewater containing a large amount of organic substances and having a high salt concentration is human waste and livestock waste and food processing wastewater. Human waste should be treated and disposed of in a public sewage treatment plant along with other wastewater, but returns to fertilizer, ocean dumping,
It is treated in human waste treatment facilities (including household septic tanks) and other methods. Other than this human waste treatment facility (anaerobic or aerobic treatment), there are various hygienic problems, and the inflow to the ocean also causes red tides, which leads to troubles. The human waste treatment by anaerobic digestion method, etc., which is widely practiced in local governments, removes coarse impurities from the introduced human waste with a screen and then keeps it at 30 to 37 ° C in the digestion tank for about 3
Digest for 0 days, adjust the BOD (biochemical oxygen demand) of the desorbed solution to an appropriate dilution, perform aerobic treatment with a spray filter bed, sterilize with chlorine, and then discharge. Methane gas generated at this time is used as fuel, and digested sludge is used as fertilizer. Also,
The present situation is that the treatment process for sewage and various wastewater is also adjusted even if the treatment process is slightly different, and the amount of sludge generated by this treatment continues to increase. -Disposal is extremely difficult and has become an important issue. In the past, part of it was used for landfill and after dehydration and drying as agricultural land improvement and fertilizer, but it is not always the proper method when considering the characteristics of the sludge itself and geographical conditions, etc. Is hard to say.

[0003]

DISCLOSURE OF THE INVENTION The present invention reduces the amount of sludge generated in a wastewater treatment method of wastewater containing a large amount of conventional organic substances and having a high salt concentration, and is simple, safe and economical. And to convert it into a sanitary and harmless end product,
Reduce the huge equipment costs and maintenance costs of conventional wastewater treatment facilities.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to a method for treating wastewater containing a large amount of organic substances.
No. 42, No. 1534061, No. 1594104
No. 1618609, ozone (O ₃ ) and oxygen atoms (O) are reacted with a desorbed liquid (hereinafter, referred to as a filtrate) generated by pretreatment (hereinafter, referred to as solid-liquid separation) and oxidized. It is solved by the process of detoxification and detoxification. In the solid-liquid separation process, it is separated into a solid matter and a filtrate, and the former is made into fuel and incinerated by self-combustion. The exhaust heat boiler is operated by the heat energy of the combustion exhaust gas generated at this time to generate saturated steam, and the latter filtrate is adjusted in pH and then the generated steam is used to condense the vaporized material. , Fine solids (suspended substances and salts) contained in this filtrate
Is separated and taken out as a crystalline substance. The condensed filtrate remaining thereafter is premixed with ozone (O ₃ ), sprayed in the reaction tank in the form of ultrafine particles, and then irradiated with ultraviolet rays,
The suspended matter and odor contained in the filtrate are quickly redox-removed and removed, and the remaining suspended matter and odor are promptly redox-removed by reacting with oxygen atoms (O). In addition, the odorous air generated in the solid-liquid separation process is collected, mixed with ozone, and removed by oxidation reduction to make it harmless, thereby providing an efficient and inexpensive treatment method. The solid-liquid separation treatment method involves adding flocculant in the raw wastewater tank during the solid-liquid separation process, and then quickly forming flocs by aeration, and then using a separator equipped with a special net conveyor in two stages. Since the solid waste and the filtrate can be easily separated by providing the raw wastewater by gravity fall, the load of suspended substances contained in the filtrate can be reduced, and therefore the subsequent treatment can be performed very easily. After the mixture is mixed with ozone, the load of pollutants contained in the filtrate is drastically reduced by irradiating it with ultraviolet rays and rapidly oxidizing and reducing it, and further reacting it with a catalyst and sodium hypochlorite or ozone to obtain oxygen. By generating atoms and rapidly reacting with the filtrate, redox and removing the remaining pollutants, and collecting odorous air generated during the solid-liquid separation process and mixing it with ozone. , Redox and remove.

[0005]

[Operation] Waste liquid that contains a large amount of organic substances and also has a high salt concentration is subjected to solid-liquid separation, then heated and evaporated to vaporize and condense, and fine suspended substances contained in this And salt are extracted, and the filtrate is mixed with ozone and reacted to remove the remaining pollutants by redox.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the processing method of the present invention will be described with reference to FIG. 1 is a system diagram showing the concept of a method for treating wastewater containing a large amount of organic substances and having a high salt concentration. First, raw wastewater a flows into a raw wastewater tank 1, and an air diffusion pipe is provided at the bottom of the tank 1. No. 2 is provided, while the raw wastewater a is moderately stirred by the air b, the flocculant c is appropriately added to form flocs in the tank 1, and No. Special No. 1 provided in the solid-liquid separator 3. 1 Transfer to the net conveyor 4. The conveyor 4
Has a structure (not shown) capable of selecting a special mesh according to the flock formation condition of the raw wastewater a and adjusting the conveyor speed according to the flock formation condition. Here, the solid matter (hereinafter referred to as "sludge") d and the desorbed liquid (hereinafter referred to as "filtrate") e are separated by gravity falling in a natural state. No. 1 after air b was sent to the air diffuser 2 provided at the bottom of the relay tank 5 and the floc was formed by adding the flocculant c while appropriately stirring the sludge d. 2 Special No. provided on the solid-liquid separator 6 2 Transfer to the net conveyor 7. Here, No. 1 The same operation as the solid-liquid separator 3 is repeated to separate the sludge d and the filtrate e. The separated sludge d is transferred to the dehydrator 8 and then is made into sludge having a water content of 70% or less by a powerful demineralization and separated into a filtrate e. The filtrate e generated at the above-mentioned three places is the filtrate storage tank 2
4 and neutralized with the pH adjusting solution k and stored. One sludge d is stored in the sludge storage tank 9 by a carrier (not shown), and a fixed amount cutting machine 10 provided at the bottom of the tank 9
Quantitative carry-out with a fixed quantity feeder 11 with a carrier (not shown)
And is inserted into the swirling fluidized bed incinerator 12 of Japanese Patent No. 1227242. The incinerator 12 uses silica sand as a heat medium in order to enable the self-combustion of the sludge d in advance.
o. 1 A forced air blower 15 blows air b to the air preheater 14 and preheats (300 to 350 ° C.) hot air b ′ while filling the silica sand to a predetermined temperature (550 to 600 ° C.)
A swirling fluidized bed is formed on the
o. 2 The forced air is blown into the incinerator 12 by the forced air blower 16, and the sludge d inserted is instantly dried and burned to reduce the amount of the sludge d. The incombustible material i inserted into the incinerator 12 together with the sludge d is carried out together with a part of silica sand, which is a fluid medium, from a carry-out port provided at the bottom of the apparatus 12 and an incombustible material separator (not shown) and a carrier ( After separation (not shown), the silica sand is successively returned into the device 12. The start-up required for setting the temperature field of the device 12 is performed by burning the oil burner with oil f as fuel. Exhaust gas generated by the self-combustion of the sludge d is attracted to the cooling smoke washing tower 13 via the exhaust gas outlet of the device 12, where there is a risk of pollution such as dust, sulfur oxides and hydrogen chloride in the gas. In order to remove the substance, an alkaline liquid (neutralizing agent) g is sprayed into the tower 13 together with the treated water e ″ ′ to treat pollutants and reduce the gas temperature to about 450 ° C. This exhaust gas , Is attracted to the air preheater 14 via the exhaust gas outlet of the tower 13. Here, the No. 1 forced draft blower 15 sends the air b to the preheater 14 for heat exchange so that each hot air b '. The exhaust gas drops to about 300 ° C. by heat exchange with the air b and is attracted to the electrostatic precipitator 17 through the outlet of the preheater 14 where the dust is collected and the bottom part is collected. The discharge machine provided in Unloaded to. The tower 13 is transported to the ash hopper 19 to the reservoir in the preheater 14 and 該機 respective bottom conveyor 18 collects dust from the 17 unloading the curb to ashes j ash conveyor 20.
The exhaust gas passing through the outlet of the machine 17 is discharged to the waste heat boiler 21.
Is saturated with water vapor h ′ by heat exchange with the water h supplied to the boiler 21 by the thermal energy of the exhaust gas.
No. was generated and the generated steam was used. 1 steam heater 28, No. 1 2 Heat the steam heater 33. The exhaust gas passing through the outlet of the boiler 21 is discharged to the atmosphere through the chimney 23 through the induced air blower 22. Further, the filtrate e stored in the filtrate storage tank 24 is the pH adjusting liquid k.
After adjusting the pH with the preheater 25, the heater 26, the evaporator 27, and the No. It injects to the upper limit setting position of the float switch (not shown) provided in the crystal can 29 via 1 steam heater 28. Next, saturated steam h'generated in the waste heat boiler 21 is injected into the evaporator 27 and the crystal can 29 by opening a steam valve (not shown), and the respective cans 27, 2
The inside of 9 is heated and boiled by the latent heat of the water vapor h '. Eventually, the previously injected filtrate e boils and vaporizes while generating steam. When the switch is operated at the upper limit operation position of the float switch provided in the crystal can 29, the supply of the water vapor h ′ is stopped and all pumps (not shown) for sending filtrate e are continuously activated. Driving starts. The filtrate e in the filtrate storage tank 24 passes through the preheater 25 and is supplied in the opposite direction to the evaporated filtrate e ′ (around 90 ° C.),
Here, heat is exchanged and the temperature is raised to around 70 ° C. On the other hand, the filtrate e ′ was cooled to 40 to 30 ° C. 2 relay tank 34
Stored in. The filtrate e (about 70 ° C.) whose temperature has been raised and a part of the filtrate e in an evaporated state are extracted from the bottom of the evaporator 27 and merged into the filtrate e, which passes through the heater 26 and is the condensed filtrate e after vaporization. It is supplied in the direction opposite to that of '(around 100 ° C.), but in order to maintain the condition just before boiling, it is heated by the vessel 26, supplied to the evaporation can 27, and instantaneously boiled and vaporized, and the filter in the can 27 is evaporated. Liquid e is concentrated. The concentrated filtrate e ″ is
From the bottom of the crystal can 29, the concentrated filtrate e ″, the concentrated filtrate e ″ separated by the cyclone 30 and the concentrated filtrate e ″ separated by the crystal separator 31 are brought together to form No. 1 steam heater 28. It is supplied to the crystal can 29 while maintaining a predetermined temperature of the filtrate e ″ by indirect heating using the water vapor h ′. Here, the concentrated filtrate e ″ in the can 29 further promotes boiling and vaporization, reaches the saturated concentration of the contained components, and begins to crystallize.
The crystal separation water m ′ is supplied to the cyclone 30, and a rotational movement is given to separate the fine particles (crystals) of the crystal separation water m ′ to utilize the centrifugal force of the rotating particles to melt the crystal m. Liquid crystal separation water m'is separated. The former is collected by a crystal substance separator 31 from an outlet provided at the bottom of the cyclone 30 and carried out to the outside from an outlet provided at the bottom of the cyclone 30. The latter is concentrated from the cyclone 30 upper outlet, the crystal separation water m ′ outlet provided in the vessel 31 and the bottom of the crystal can 29 and a part of the crystallized concentrated filtrate e ″ and the evaporator 27. After concentrating the concentrated filtrate e ″, No. It is fed to the can 29 as described above via the 1 steam heater 28. On the other hand, the filtrate e ′ evaporated in the evaporator 27 and the crystal can 29 is separated into steam and water by the mist separator 32. 2 The steam heater 33 indirectly heats the saturated steam h ′ to maintain a predetermined temperature, and the heat exchange is performed by the heater 26 and the preheater 25 as described above, and the condensed filtrate e ′ is cooled to 40 to 30 ° C. No. 2 Stored in the relay tank 34. In order to compensate for the amount of heat to be lost, saturated steam h'generated in the heat generating boiler 21 is appropriately supplied by a set temperature instruction (not shown) to the evaporation can 27 and the crystal can 2.
9 is directly supplied to supplement the amount of heat loss with the latent heat, and the preheater 25, the heater 26, No. 1 steam heater 28 and No. 1 The saturated steam h'is circulated in the 2 steam heater 33, and the above process is automatically continuously operated while maintaining a predetermined temperature. Ozone (O ₃ ) p generated by an ozone generator (not shown) is mixed with the condensed filtrate e ′ and then sprayed in the form of ultrafine particles in the reaction tank 35.
The suspended solids and odors are rapidly removed by redox. Further, in the oxidation catalyst tower 37, hypochlorous acid (NaO
Cl) q or the ozone p is reacted with the catalyst r packed in the tower 37 to generate oxygen atoms o, and the condensed filtrate e ′
The suspended solids and odor are promptly redox-removed by reacting with and stored in the treated water storage tank 38, and then appropriately discharged or provided for reused water. Further, odorous air generated during the solid-liquid separation process is collected and mixed with ozone p to be redox-removed. Although the catalyst r packed in the oxidation catalyst tower 37 is washed with the treated water e ″ ′, the backwash wastewater n used for the washing is sent to the filtrate storage tank 24 for reprocessing.
Further, odorous air generated during the solid-liquid separation process of the treatment method is collected and mixed with ozone p for redox removal.

[0007]

INDUSTRIAL APPLICABILITY The present invention separates solid matter and desorbed liquid into fuel, and uses a swirling fluidized bed incinerator having excellent combustion efficiency for self-combustion and incineration treatment, and does not require any auxiliary fuel from others. Complete combustion processing is possible, and the exhaust heat boiler operates with the heat energy of the exhaust gas generated at this time to generate saturated steam, and the saturated steam heats the desorbed liquid to evaporate and condense the evaporated gas. , The salt is extracted as crystals. In addition, the amount of sludge generated can be drastically reduced, the quality of treated water can be stabilized and harmless, and the natural destruction of treated water can be completely prevented, and it is extremely efficient compared to conventional water treatment methods. The construction cost of the processing equipment can be greatly reduced, the same result can be obtained in terms of running cost, and the labor cost is extremely superior to other processing methods compared to conventional processing methods. .

[Brief description of drawings]

FIG. 1 is a conceptual system diagram showing a wastewater treatment method according to an embodiment of the present invention.

[Explanation of symbols]

1 ... Raw waste water tank, 2 ... Air diffuser, 3 ... No. 1 solid-liquid separator, 4 ... No. 1 Net conveyor 5 ... No. 1 relay tank, 6 ... No. 2 solid-liquid separator, 7 ... No. 2 Net conveyor, 8 ... Dehydrator, 9 ... Sludge storage tank, 10 ... Fixed quantity cutting machine, 11 ... Fixed quantity feeder, 12 ... Swirling fluidized bed type incinerator, 13 ... Cooling and washing tower, 14 ... Air preheater, 15 ... N
o. 1 push fan, 16 ... No. 2 push blower, 17 ...
Electric dust collector, 18 ... Carrier, 19 ... Ash hopper, 20 ... Ash carrier, 21 ... Waste heat boiler, 22 ... Induction blower, 23 ...
Chimney, 24 ... Filtrate storage tank, 25 ... Preheater, 26 ... Heater, 27 ... Evaporator, 28 ... No. 1 steam heater, 2
9 ... Crystal can, 30 ... Cyclone, 31 ... Crystal separator,
32 ... Mist separator, 33 ... No. 2 steam heater, 34 ... No. 2 relay tank, 35 ... reaction tower, 36 ... ultraviolet ray, 37 ... oxidation catalyst tower, 38 ... treated water tank, a ... raw wastewater,
b ... air, b '... hot air, c ... flocculant, d ... sludge, e ... filtrate, e' ... condensed filtrate, e "... concentrated filtrate, e"'... treated water, f ... oil, g ... Alkaline liquid (neutralizer), h ... water,
h '... saturated steam, i ... incombustibles, j ... ash, k ... pH adjusting liquid, m ... crystals, m' ... crystal separation water, n ... backwashing wastewater, o
... oxygen atom, p ... ozone, q ... sodium hypochlorite, r ...
catalyst

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C02F 9/00 Z ZAB 503 C 504 B B01D 53/34 ZAB 53/38 53/74 C01B 13/10 D C02F 1/00 ZAB F 1/04 ZAB D 1/26 ZAB A 1/32 ZAB 1/58 ZAB G 1/76 ZAB Z 1/78 ZAB

Claims (1)

[Claims] 1. A wastewater containing a large amount of organic substances and having a high salt concentration is subjected to a pretreatment (hereinafter referred to as solid-liquid separation) to obtain a solid matter (hereinafter referred to as sludge) and a desorbed liquid (hereinafter referred to as sludge).
It is called filtrate. ), The solid matter (hereinafter referred to as “sludge”) is converted to fuel and incinerated. The heat energy generated by the solid waste is used to operate the exhaust heat boiler to generate saturated steam, which is then desorbed. The separated liquid is heated to evaporate and the vaporized substance is condensed to extract fine solid matter (suspended substance and salt) contained therein as a crystalline substance. After the desorbed liquid (filtrate) is stored in the filtrate storage tank, it is sequentially heated by a preheater and a heater, passes through an evaporator, a steam heater, and is further boiled and vaporized in a crystallization can. The filtrate is separated into a filtrate and a crystal substance by a cyclone, and the crystal substance is collected by a crystal separator. The vaporized filtrate is separated into water and water by a mist separator, and the condensed filtrate is kept at a predetermined temperature with a steam heater and passed through a heater and a preheater to lower the temperature by heat exchange and store the filtrate in a relay tank. To do. The condensed filtrate stored in the relay tank generates oxygen (O ₂ ) from air by an oxygen production device, and ozone (O ₃ ) is generated by this oxygen by an ozone generator, and this ozone is mixed with the condensed filtrate. Ultrafine particles are atomized and sprayed in the reaction vessel above, and the suspended matter and odor are rapidly removed by redox treatment by irradiating with ultraviolet rays. Further, in the oxidation catalyst tower, sodium hypochlorite (NaOCl) or ozone is contact-reacted with the catalyst packed in the tower to generate oxygen atoms (O), and the residual suspension is reacted with the condensed filtrate. Wastewater treatment characterized by rapid redox removal of substances and odors, and redox removal by collecting odorous air generated during solid-liquid separation process and mixing with ozone Method.