JP3353123B2 - Wastewater purification treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for purifying sewage. Specifically, the present invention relates to a method and an apparatus for purifying sewage by effectively using natural shells.

[0002]

2. Description of the Related Art Biological purification treatment of wastewater is widely performed, and a representative example thereof is an activated sludge method. Purification treatment of sewage by the activated sludge method is generally performed through a treatment process as shown in FIG. 1, and after removing sand having a large specific gravity contained in the sewage in a sand basin 1 as necessary, First, suspended substances (suspended substances) in sewage are removed by sedimentation basin 2 (hereinafter, sedimentation basin and sedimentation apparatus are collectively referred to as “sedimentation apparatus”), and then aeration tank (aerobic biological treatment apparatus) The wastewater is treated with activated sludge under aerobic conditions while being aerated in step 3 to adsorb and oxidize polluting components such as organic substances in the wastewater. The supernatant is separated into a solid substance such as activated sludge and a supernatant liquid, and the supernatant liquid discharged from the final sedimentation device 5 is treated by the coagulation treatment device 7 through the discharge passage 6 and discharged from the discharge passage 8. .

[0003] In the biological purification treatment as described above, it is important that the growth and activity of organisms that purify water are maintained well. Therefore, nitrogen, phosphorus, and the like, which are nutrients of the organisms, are important. The required amount must be contained in the sewage,
When nitrogen or phosphorus in sewage is insufficient, it is supplied from outside. In the case of a biological purification treatment such as the activated sludge method, the pollutants such as organic substances in the sewage are reduced by adsorption, oxidative decomposition, digestion by organisms, etc. Is purified, and at the same time, nitrogen and phosphorus in the wastewater are digested and reduced as nutrients of living organisms. However, in the water discharged from aeration tanks, final sedimentation basins, coagulation treatment equipment, etc., a considerable amount of phosphorus is not completely removed in the form of phosphate etc., and remains in rivers and lakes. If released into rivers and rivers, it may lead to nutrient enrichment in rivers, lakes, lakes and the sea, causing abnormal occurrence of plankton and other creatures, and possibly causing destruction of nature.

[0004] Therefore, after a biological purification treatment under aerobic conditions, solid waste such as activated sludge is precipitated and separated in a final sedimentation basin, and the discharged water (supernatant water) contains slaked lime, bansulfate, organic polymer and the like. It is common practice to add coagulants to remove phosphates and other components (heavy metals, trace oils, slightly residual organic substances, etc.) into insoluble agglomerates, remove them by agglomeration, and then discharge them to rivers, etc. Have been done.

[0005] However, in the case of such a conventional method in which a flocculant such as slaked lime, bansulfate, or an organic polymer is added to the water discharged from the final sedimentation basin, phosphates and the like contained in the discharged water are rapidly flocculated. It is convenient to be able to precipitate and separate the flocculant, but since a large amount of the flocculant is supplied, a large amount of the flocculant tends to remain in the treated water, and the flocculant is constantly Since it is necessary to supply, management and operation thereof are troublesome and costly. In particular, when an organic polymer is used as a coagulant, there is a problem that the cost is high and the cost is high.

On the other hand, in shellfish farms and processing plants, a large amount of shells remain after the shells are taken out, but the shells are flame-retardant and extremely hard, and are difficult to be decomposed or chemically decomposed by microorganisms. Therefore, treatment by combustion, compression, decay, chemical decomposition, and the like is difficult, and if left as it is or discarded, its peculiar odor gives off a bad smell to the surroundings, and its handling has been troublesome. From this point, attempts have been made to effectively use shells for water purification, but in that case, the purpose is to use shells as attachment members for the inhabitation and propagation of water purification organisms, It has not been actively used to remove phosphorus and the like in sewage.

[0007]

The present inventor has accumulated many years of research on sewage treatment, preservation and improvement of the natural environment, and beautification, and has a track record of putting many technologies to practical use for that purpose. Investigations have been repeated with the aim of developing a method that can easily and inexpensively remove contaminants such as phosphorus contained in effluent discharged after biological sewage treatment, which are conventionally difficult to remove. As a result, it was found that if the above-mentioned shells, which had been difficult to handle in the past, were used as a purifying material, especially after being heated and fired, contaminants such as phosphorus in water could be removed, and the shell could be effectively used. Completed the invention.

[0008] That is, the present invention is a method for purifying sewage, wherein the sewage that has been biologically purified under aerobic conditions is further treated using shells that have been heated and fired.

Further, the present invention relates to a sewage purification treatment apparatus provided with an aerobic biological treatment apparatus and, if necessary, a sedimentation apparatus and / or a flocculation treatment apparatus, wherein the treatment water is discharged from the biological treatment apparatus. A heat-fired shell is disposed in at least one of a channel, an interior of a sedimentation apparatus, a drainage path of treated water from a sedimentation apparatus, an interior of a coagulation treatment apparatus, and a discharge path of treated water from a coagulation treatment apparatus. Wastewater purification treatment device.

In the present invention, the type of sewage to be treated is not particularly limited, and examples thereof include various types of industrial effluent, office effluent, domestic effluent, marsh lake, river, pond, sea and the like. The contents of the sewage are not particularly limited.

As a method of biologically purifying sewage under aerobic conditions, an activated sludge method is widely known. The method is not limited, and any of conventionally known aerobic biological purification treatment methods can be adopted. In addition to the activated sludge method, for example, an aeration-type oxidation pond method (aeration-type lagoon method), a biofilm method,
A trickling filter method, a biological stabilization pond method, a rotating plate method, a contact aeration method, or the like may be employed. At that time, the shape of the biological treatment device,
The structure, scale, auxiliary facilities, and the like are not particularly limited, and may be any. Among the biological purification treatment methods described above, the activated sludge method is preferable. In this case, the activated sludge method includes, for example, a standard activated sludge method, a complete mixing method, a dispensing method, an oxidation ditch method, and pure oxygen. Method, ultra deep aeration method, or the like.

The conditions for the biological purification treatment are not particularly limited, and it is preferable to select optimal conditions as appropriate according to the type of sewage, the purification treatment method, the scale and structure of the apparatus, and the like.
The sewage can be directly introduced into the biological treatment apparatus as described above, or if necessary, a sand basin and / or a first sedimentation basin (first sedimentation apparatus) can be provided upstream of the aerobic biological treatment apparatus. Then, they may be processed by those devices and then introduced into a biological processing device. Further, in the case of sewage, for example, concentrated wastewater such as molasses wastewater during alcohol fermentation or yeast production, human wastewater, etc., an anaerobic biological treatment device is provided upstream of the aerobic biological treatment device. Alternatively, the wastewater may be biologically treated under anaerobic conditions in advance to reduce the pollutant concentration (BOD or COD), and then biologically purified under aerobic conditions.

[0013] Then, the sewage treated under the aerobic condition in the biological treatment apparatus is preferably guided to a settling apparatus to remove activated sludge and other solids contained therein, and to remove the same.
Further, if necessary, the treated water is discharged after the coagulation treatment by the coagulation treatment device. However, in the present invention, the discharge passage from the biological treatment device, the inside of the sedimentation device, the discharge passage from the sedimentation device, the coagulation treatment device And a shell (hereinafter, referred to as “baked shell”) that is heated and baked is disposed in at least one portion of the inside of the container and at least one of the discharge paths from the coagulation treatment apparatus.

The location of the baked shells will be described with reference to FIG. 1. The discharge path 4 from the biological treatment apparatus 3, the inside of the final sedimentation apparatus 5, the discharge path 6 from the sedimentation apparatus 5, the coagulation treatment apparatus 7 The fired shells are arranged in the inside and at least one of the discharge paths 8 from the coagulation treatment device 7 to remove contaminants such as phosphate contained in water.

In this case, it is desirable to dispose the burned shell in at least one of the discharge path 6 from the sedimentation device 5 and the inside of the coagulation treatment device 7 so that phosphates and the like can be more effectively removed. Of fired shells in the discharge path 4 from the chemical treatment device 3, the inside of the sedimentation device 5, the discharge passage 6 from the sedimentation device 5 and the inside of the coagulation treatment device 7, or the discharge passage 4 or the sedimentation device 5 may be arranged only on one side.

The shell in this case may be any of seawater, freshwater, or a shell of shellfish that inhabits a mixed area of seawater and freshwater, such as scallops, oysters, pearl oysters, clams, clams, clams, green goats, and crows Shells such as shellfish, turtle shells, and millet shells can be mentioned, and those that can be obtained in large quantities and regularly at shellfish farms and processing plants are preferable.
Further, only one kind of shell may be used, or two or more kinds may be used.

The shell used in the present invention is 500
It is necessary to heat and bake at a high temperature of at least 1000C, preferably at least 1000C. By using a baked shell, contaminants such as phosphorus in wastewater can be removed very effectively. Although the mechanism has not been fully elucidated, heating and baking the shell at a high temperature increases the ability of calcium ions to be released from the shell, and the calcium ions released into water combine with phosphate ions. Insoluble calcium phosphate
Alternatively, it is presumed that the phosphate ion adsorbing ability of the shell is enhanced, and phosphate ions in water are adsorbed and removed.

The calcined shells may be whole, not crushed or crushed;
It is preferable to use one crushed to about 40 mm, particularly about 5 mm to 30 mm. At this time, the pulverization may be performed at any stage before or after the calcination, but the calcination after the pulverization is preferable. The fired shell used in the present invention is
The baking treatment also removes and removes organic components such as proteins remaining on the shell, which is the cause of the propagation of putrefactive bacteria and the generation of odors, as well as the removal of carbon and moisture. There is no unpleasant odor, and the quality is stable and good.

At this time, the baked shells may be placed in the above-mentioned places in the form of separated granules by spraying or the like, or a bag made of a water-permeable net or cloth, plastic having a hole, metal, wood, or the like. A permeable container composed of such as, a basket or the like may be filled with a baked shell and placed at the above-mentioned location, or the baked shell may be solidified to an appropriate size with a binder or the like and placed at the above-mentioned location. Good. From the viewpoint of ease of handling, easy placement in a predetermined place, easy removal from the place, and the like, it is convenient to fill and use bags, baskets, and other containers. In arranging the baked shells, it is necessary to adjust the arrangement position, the amount of use, and the like so that the original processing of the apparatus, the flow of water, and the like are not significantly hindered.

Although not particularly limited, an example of the arrangement of the baked shells will be specifically exemplified with reference to the drawings. When the baked shells A are arranged in the discharge paths 4, 6, 8, etc., the arrangement in FIG. a)
As shown in FIG. 2B, the entire discharge path may be filled and disposed, or as shown in FIG. 2B, may be disposed only below the discharge path.

When the baked shell is disposed inside the settling device 5 or the coagulation treatment device 7, for example, as shown in FIG. 3A, the baked shell A is located slightly above the bottom of the device.
It is convenient to arrange so as not to mix with the sediment deposited on the bottom of the apparatus. In the case of using a fired shell A having a large particle size, for example, as shown in FIG. 3B, a fired shell having holes or the like near the bottom of the sedimentation device 5 or the treatment device 7 through which sediment can pass is provided. A perforated plate (shelf plate) 9 on which the shell A is placed may be provided, and the fired shell A may be arranged there.

In the present invention, the baking shells arranged in the discharge path 4, the sedimentation apparatus 5, the discharge path 6, the coagulation processing apparatus 7 and / or the discharge path 7, and the fired Unshelled shells may be placed, in which case the unfired shells will serve as habitats for living organisms having a water purification function, and can promote the growth, proliferation and habitation of the living organisms, and can be handled conventionally. The increased use of shells, which have been a problem, has contributed to their effective use.

Further, in the present invention, when the water discharged from the sedimentation apparatus is subjected to the coagulation treatment using the above-mentioned coagulant such as bansulfate, slaked lime and organic polymer by the coagulation treatment apparatus, the fired shells are used. By doing so, it is also possible to reduce the amount of these coagulants used.

[0024]

According to the present invention, a shell which has been regarded as one of the sources of pollution is effectively used as unnecessary waste, and contaminants such as phosphorus in sewage are easily and inexpensively removed. Or it can be reduced. The baked shell used in the present invention does not generate an odor or the like, and is derived from a natural product, so that it is highly safe and has good handleability. Further, in the case of the present invention, it is possible to reduce the use amount of the coagulant such as bansulfate, slaked lime and organic polymer which have been conventionally used, or to avoid the use thereof. Contribute.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a typical flow sheet of a biological purification treatment of sewage.

FIG. 2 is a view showing an example in which fired shells are arranged in a discharge path in the present invention.

FIG. 3 is a view showing an example in which a fired shell is disposed inside a precipitation apparatus or a coagulation treatment apparatus in the present invention.

[Explanation of symbols]

 A Fired shells 1 Sedimentation basin 2 First sedimentation basin (First sedimentation device) 3 Biological treatment device 4 Drainage channel 5 Sedimentation device 6 Drainage channel 7 Aggregation treatment device 8 Drainage channel 9 Eye plate (shelf plate)

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C02F 1/28 C02F 1/58 C02F 3/28-3/34 B01D 15/00-15/08 B01D 39/00-41 / 04 B01J 20/00-20/34

Claims (3)

(57) [Claims] 1. A method for purifying sewage, which comprises subjecting sewage that has been biologically purified under aerobic conditions to heat and calcined shells. 2. The sewage is treated under aerobic conditions by a biological treatment device, and then guided to a sedimentation device as needed to remove sediment, and a coagulation treatment is optionally performed by a coagulation treatment device. Then, in a method for purifying sewage comprising discharging treated water, a discharge path of treated water from the biological treatment apparatus, an inside of the settling apparatus, a discharge path of treated water from the settling apparatus,
A method for purifying sewage, comprising disposing heated and fired shells in at least one of the inside of the coagulation treatment apparatus and the discharge path of treated water from the coagulation treatment apparatus. 3. A sewage purification treatment device equipped with an aerobic biological treatment device and, if necessary, a sedimentation device and / or a coagulation treatment device, wherein a discharge path of treated water from the biological treatment device, Wastewater characterized by disposing a heated and fired shell in at least one of the inside of the apparatus, the passage of treated water from the sedimentation unit, the inside of the coagulation unit and the passage of treated water from the coagulation unit. Purification equipment.