JP2015123402A - Waste treatment method, waste treatment apparatus for executing the method, fired pellets manufactured by the method or the apparatus, and bottom sediment improving method using the fired pellets - Google Patents

Abstract

PROBLEM TO BE SOLVED: To treat inorganic waste, such as dredged sludge, and organic waste, such as sewage sludge as at low cost as possible.SOLUTION: Organic waste abundantly containing organic substance is combined with inorganic waste, such as dredged sludge at a predetermined ratio, combined sludge obtained by the mixture and combination is pelletized and formed into sludge pellets of an approximately spherical shape, the sludge pellets are filled into a sludge pellets firing furnace, the sludge pellets filled in the sludge pellets firing furnace are allowed to spontaneously burn from below to above, and valuable fired pellets which are harmless by the spontaneous burning is obtained.

Description

  The present invention relates to a waste treatment method for obtaining calcined pellets using inorganic waste and organic waste as raw materials, a waste treatment apparatus for carrying out this method, this method or the calcined pellets produced by this apparatus, and this calcined product The present invention relates to a method for improving bottom sediment using pellets.

  In recent years, in water areas such as lakes, rivers, canals, harbors, and coasts, especially in those areas where water does not flow in and out, the concentration of pollutants is high due to the inflow of domestic wastewater, and the eutrophication of water quality is remarkable. Plankton is generated in large quantities, and a large amount of these dead bodies are also generated. Therefore, the bottom of these water areas is covered with sludge made of pollutants and dead bodies of plankton.

  These sludges that cover the bottom of the water are rich in organic matter, which decomposes in an oxygen-deficient state, generates odors and harmful substances, drowns aquatic organisms, and reduces the yield of farmed fish. Also, in lakes and rivers, this sludge covers the surface of the sandy bottom, deprives the habitat of shellfish and other shellfish that inhabit the sandy land, and drastically reduces their catch.

  Therefore, conventionally, in order to improve such a situation, measures have been taken to remove the sludge from the bottom of the water. However, there is a problem that the area of the bottom of the water such as lakes, rivers, canals, harbors, and coasts is large, the amount of sludge to be dredged is enormous, and it takes a lot of money to drown the sludge on the bottom.

  In addition, sludge removed by dripping contains abundant organic matter, and if it is deposited on land as it is, it will rot and generate odors and harmful substances, so it must be solidified or incinerated. Since the amount of sludge removed in this way was very large, there was also a problem that a huge cost was required for the solidification treatment and incineration treatment.

  As dredging is so expensive, a method may be used in which the bottom of the bottom is covered with clean sand and the bottom of the bottom is covered with clean sand. This method has the advantage that the bottom of the water can be easily made into sand at a relatively low cost, and the catch of shellfish such as swordfish can be increased at a low cost.

  However, in order to spread clean sand on the bottom of the water, it is necessary to obtain good quality sand. However, in addition to the problem of depletion of sand resources, the acquisition of good quality sand has the problem of destroying the environment of the sand collection site. In recent years, it has been very difficult.

  In addition, even if sand is covered with sludge, sludge is still present under the sand, which decomposes in anoxic conditions, causing harmful substances and odors to leak into the water for a long time. In addition, there is a problem that even if the fine sand is overlaid on the sludge, the sand may sink into the sludge, which is not a fundamental solution.

  In addition, when clean sand is covered on sludge, sand is further laminated on sludge, so the bottom of the water becomes shallow, reducing the storage capacity of the lake as a reservoir, and hindering navigation of the ship. Or destroy the aquatic ecological environment.

  So far, the problem of sludge on the sea floor has been explained, but construction sludge, sedimentary sediment, bentonite mud, coagulated sediment sludge, sand washed sludge, concrete sludge, incinerated ash, dust collection dust, foundry sand, The treatment of inorganic wastes such as slag, glass scraps, debris, dust and slag is also a problem.

Japanese Patent No. 4608658 JP 2005-185905 A Japanese Patent Laid-Open No. 2005-030074

  The problem to be solved by the present invention is that the above-described inorganic waste cannot be treated at low cost.

  In the present invention, in order to treat inorganic waste at low cost, organic waste rich in organic matter is mixed with the inorganic waste at a predetermined ratio, and mixed sludge obtained by this mixing is produced. The sludge pellets are formed into a substantially spherical sludge pellet, filled in the sludge pellet firing furnace, and the sludge pellet filled in the sludge pellet firing furnace is self-combusted from below to above, The most important feature is to obtain valuable calcined pellets detoxified by.

  Here, inorganic waste means construction sludge, sedimentary sediment, bentonite mud, coagulated sediment sludge, sand washed sludge, concrete sludge, clean water sludge, incineration ash, dust collection dust, foundry waste sand, slag, glass scrap, Debris, dust, slag, etc. Organic waste refers to activated sludge, digested sludge, sewage sludge, paper sludge, food waste, fermented residue, animal manure, or compost of these.

  In the present invention, organic waste rich in organic matter is mixed with inorganic waste at a predetermined ratio to form mixed sludge, and the mixed sludge is formed into sludge pellets. When ignited, the sludge pellets are self-combusted to become calcined pellets. Therefore, it is possible to obtain harmless valuable calcined pellets at low cost without using fuel separately from mixed sludge as a raw material. There is.

  And since the present invention can obtain harmless valuable calcined pellets at low cost without using fuel separately from inorganic waste, the calcined pellets are returned to the seabed. By this, there is an advantage that the water bottom can be returned to an environment convenient for inhabiting shellfish such as swordfish at low cost.

FIG. 1 is an explanatory view of an example of a waste treatment apparatus according to the present invention. FIG. 2 is an explanatory view of a calcined pellet forming apparatus constituting a part of an example of the waste treatment apparatus according to the present invention. FIG. 3 is a process diagram showing each process of the waste treatment method according to the present invention.

  The present invention has achieved the object of treating inorganic waste such as sludge covering the water and sea bottom at the lowest possible cost without damaging the environment.

  FIG. 1 is an explanatory view of an example of a waste treatment apparatus according to the present invention, and FIG. 2 is an explanatory view of a calcined pellet forming apparatus that constitutes a part of an example of a waste treatment apparatus according to the present invention. In these drawings, 10 is a sludge mixing device for mixing sludge and sewage sludge to obtain mixed sludge, and 12 is a granulation for forming the mixed sludge obtained by the sludge mixing device 10 to obtain a substantially spherical sludge pellet. An apparatus 14 is a sludge pellet firing furnace for firing the sludge pellets obtained by the granulating apparatus 12 to obtain fired pellets.

  As the sludge mixing device 10, a disturbance device such as a concrete mixer can be used. The granulating device 12 is a device that divides a lump of mixed sludge into small lumps and rolls the mixed sludge of this small lump into a substantially spherical sludge pellet, which rotates an inclined tub-like container and the container It consists of a drive device. Next to the granulating device 12, a sludge pellet charging device 16 for conveying and charging the sludge pellets formed by the granulating device 12 into the sludge pellet firing furnace 14 is installed.

  The sludge pellet firing furnace 14 is formed of a vertically long and hollow structure formed of a refractory material, and an opening 18 is provided at the top. In addition, a temperature sensor 20 is attached to the inside of the sludge pellet firing furnace 14 at a predetermined interval in the vertical direction so that the temperature in the sludge pellet firing furnace 14 can be detected at every predetermined height. Below the sludge pellet firing furnace 14, air holes 22 are formed penetrating from the side toward the inside so that external air can flow into the sludge pellet firing furnace 14 through the air holes 22.

  The air hole 22 may be connected to a blower opening (not shown) so that air can be forcibly fed into the sludge pellet firing furnace 14. In addition, an ignition device (burner) (not shown) may be provided below the sludge pellet firing furnace 14 for igniting the lower part of the sludge pellets filled in the sludge pellet firing furnace 14. Further, the sludge pellet firing furnace 14 may be provided with a pyrolysis furnace (not shown) for thermally decomposing harmful gas contained in the waste gas discharged from the sludge pellet firing furnace 14. Further, the sludge pellet firing furnace 14 may be provided with a dust collector (not shown) for collecting fine particles contained in the waste gas discharged from the sludge pellet firing furnace 14. Further, an after burner may be provided to extinguish the exhaust gas.

  A screw feeder device 24 is horizontally provided immediately below the sludge pellet firing furnace 14. In the upper part of the screw feeder device 24, an opening is formed at a portion corresponding to the lower part of the sludge pellet firing furnace 14, and the opening communicates with the lower part of the sludge pellet firing furnace 14. A spiral screw feeder 26 is coaxially provided inside the screw feeder device 24, and the screw feeder 26 is coaxially connected to a motor 28. An opening for discharging the fired pellets is provided on the tip side of the screw feeder device 24, and a fired pellet storage 30 for storing the fired pellets is provided below the opening of the screw feeder device 24.

  Next, a method of forming calcined pellets using sludge on the water seabed and sewage sludge at the sewage treatment plant will be described with reference to the process diagram shown in FIG.

  First, sludge on the bottom of the water, such as the bottom of the lake, the canal, or the bottom of the sea, is dredged by a dredger to deposit dredged sludge on the shore. After a certain period of time has passed, the accumulated soot and sludge escapes the water and seawater contained in it to some extent due to gravity, and the salt that may cause dioxin generation during combustion is demineralized by rain, It evaporates due to wind and solar heat. In addition, it may be performed chemically or mechanically in place of rain or sun-desalting or drying due to outdoor weather.

  Next, after depositing soot sludge, when a certain period of time has passed and it is judged that the soot sludge has been dried appropriately, this soot sludge is put into the sludge mixing device 10 and further the sewage sludge is turned into sludge. Add to the weight ratio and mix the sludge and sewage sludge. Here, sewage sludge is organic sludge discharged from a sewage treatment plant, and a preferable mixing ratio of dredged sludge and sewage sludge is 10: 1 to 10: 5, particularly 10: 2 to 10: 3.

  Next, the mixed sludge is put into the rotating granulator 12. The mixed sludge put in the granulator 12 is divided into small sludge masses in the granulator 12 and rolls on the granulator 12. The sludge lump that has been split into small sludge lumps is gradually formed into a spherical shape while rolling on the granulator 12 to become sludge pellets.

  Next, the substantially spherical sludge pellets formed by the granulating device 12 are conveyed onto the upper opening 18 of the sludge pellet firing furnace 14 by using the sludge pellet charging device 16, and the sludge pellets are fired from here. It is put into the furnace 14. The sludge pellets are filled and deposited so that the sludge pellets fill the inside of the sludge pellet firing furnace 14 to the top.

  After the sludge pellets are filled and deposited in the sludge pellet firing furnace 14, the bottom sludge pellets of the sludge pellet firing furnace 14 are heated by an ignition device (burner) to ignite and blow the sludge pellets. Since the sludge pellets are rich in organic matter, the sludge pellets start to burn from the bottom to the top of the sludge pellet firing furnace 14. The sludge pellets generate heat by self-combustion, dry the sludge pellets immediately above, and the top sludge pellets start self-combustion following the sludge pellets that started self-combustion, and the combustion sequentially proceeds upward. The sludge pellets that have been self-combusted are baked into baked pellets.

  Next, the screw feeder device 24 is moved, the calcined pellets are discharged from the lower part of the sludge pellet calcining furnace 14, transported to the calcined pellet storage 30, and put into the calcined pellet storage 30. The fired pellets are stored in the fired pellet storage 30. If necessary, the fired pellets are sprayed on the drowned water seabed, and the fired pellets are spread on the water seabed to regenerate the water seabed into an environment where shellfish such as swordfish are likely to live.

  In addition, when the waste gas discharged | emitted from the sludge pellet baking furnace 14 contains a harmful gas, a waste gas is guide | induced to a thermal decomposition furnace and the harmful gas in a waste gas is decomposed | disassembled with high heat | fever and detoxified. When the waste gas discharged from the sludge pellet firing furnace 14 contains fine particles, the waste gas is guided to a dust collector, and the fine particles contained in the waste gas are collected and removed.

  Further, in the above embodiment, the case where the inorganic waste is sludge on the water bottom and the organic waste is the sewage sludge of the sewage treatment plant, but the construction sludge, sedimentary sediment, bentonite mud, Coagulated sediment sludge, sand washed sludge, concrete sludge, clean water sludge, incinerated ash, dust collection dust, foundry waste sand, slag, glass scrap, debris, dust, mineral waste, etc., activated sludge as organic waste, Digested sludge, papermaking sludge, food waste, fermented residue, animal manure, or composted materials thereof are used to make sludge pellets, and the same calcined pellets can be obtained by burning this sludge pallet.

  In the above embodiment, organic waste is mixed with inorganic waste, and the mixed waste is granulated to obtain sludge pellets. The sludge pellets may be obtained by combining and forming the inorganic waste and the organic waste in a granular form so as to be wrapped in a sludge.

  Further, in the above embodiment, the screw feeder device is moved to discharge the calcined pellets from the lower part of the sludge pellet calcining furnace, but the calcined pellets are ejected from the lower part of the sludge pellet calcining furnace using a rotary valve. Also good.

  In the above embodiment, the waste gas is guided to the pyrolysis furnace, and the harmful gas in the waste gas is decomposed with high heat to make it harmless. However, the harmful gas in the waste gas is decomposed and made harmless using a photocatalyst. May be. Alternatively, the waste gas may be passed through water to dissolve and remove the harmful gas in the waste gas, and the harmful gas component dissolved in the water may be decomposed by microorganisms.

  The present invention is not limited to sludge detoxification treatment, but by adjusting the mixing ratio of inorganic waste and organic waste, artificial gravel and artificial aggregate that can be used for purposes other than sediment improvement It can also be applied to manufacturing.

DESCRIPTION OF SYMBOLS 10 Sludge mixing apparatus 12 Granulation apparatus 14 Sludge pellet baking furnace 16 Sludge pellet injection apparatus 18 Opening part 20 Temperature sensor 22 Air hole 24 Screw feeder apparatus 26 Screw feeder 28 Motor 30 Baking pellet storage

Claims (18)

  A granulation step of granulating coal sludge formed by combining organic waste with inorganic waste at a predetermined ratio to obtain a substantially spherical sludge pellet; and burning the sludge pellet in a sludge pellet combustion furnace A sludge pellet firing step for obtaining a calcined pellet; and a calcined pellet discharge step for discharging the calcined pellet from a lower portion of the sludge pellet combustion furnace, wherein the sludge pellet combustion step is filled with the sludge pellet combustion furnace. A waste treatment method, wherein the pellets are self-combusted from the lower part to the upper part of the sludge pellet combustion furnace to obtain calcined pellets.   The inorganic waste is dredged sludge, construction sludge, sedimentary sediment, bentonite mud, coagulated sediment sludge, sand washed sludge, concrete sludge, clean water sludge, incineration ash, dust collection dust, foundry waste sand, slag, glass scrap, The waste disposal method according to claim 1, wherein the waste disposal method is debris, dust, or mineral waste.   The waste according to claim 1 or 2, wherein the organic waste is sewage sludge, activated sludge, digested sludge, paper sludge, food waste, fermentation waste, animal dung, or compost of these. Material processing method.   The inorganic waste is sewage sludge, the organic waste is sewage sludge, and the mixing ratio of the sewage sludge and the sewage sludge is in the range of 10: 1 to 10: 5 by weight. The waste treatment method according to claim 1.   The inorganic waste is sewage sludge, the organic waste is sewage sludge, and the mixing ratio of the sewage sludge and the sewage sludge is in the range of 10: 2 to 10: 3 by weight. The waste treatment method according to claim 1.   The waste according to claim 1, further comprising a pyrolysis step in which the waste gas generated in the sludge pellet combustion step is heated at a high temperature to thermally decompose the harmful gas contained in the waste gas. Material processing method.   A granulating device for granulating coal sludge formed by combining organic waste with inorganic waste at a predetermined ratio to obtain a substantially spherical sludge pellet, and burning the sludge pellet obtained by the granulating device A sludge pellet combustion furnace, and a calcined pellet discharge device for discharging the calcined pellets formed after the sludge pellets are burned from the sludge pellet calcining furnace, the sludge pellet combustion furnace having the filled sludge pellets at the bottom A waste treatment apparatus characterized in that it is self-burning from the top to the top.   The inorganic waste is dredged sludge, construction sludge, sedimentary sediment, bentonite mud, coagulated sediment sludge, sand washed sludge, concrete sludge, clean water sludge, incineration ash, dust collection dust, foundry waste sand, slag, glass scrap, The waste treatment apparatus according to claim 7, wherein the waste treatment apparatus is debris, dust, or mineral waste.   The waste according to claim 7 or 8, wherein the organic waste is sewage sludge, activated sludge, digested sludge, paper sludge, food waste, fermentation waste, animal dung, or compost of these. Material processing equipment.   The waste treatment apparatus according to claim 7, further comprising a sludge pellet charging device for charging the sludge pellets into the sludge pellet combustion furnace.   The waste treatment apparatus according to claim 7, further comprising a blower that sends air into the sludge pellet combustion furnace.   The waste treatment apparatus according to claim 7, further comprising an ignition device that ignites a sludge pellet in the sludge pellet combustion furnace.   The waste treatment apparatus according to claim 7, further comprising a pyrolysis furnace that thermally decomposes harmful gas contained in waste gas discharged from the sludge pellet combustion furnace.   The waste treatment apparatus according to claim 7, further comprising a dust collector that collects the fine particles contained in the waste gas discharged from the sludge pellet combustion furnace.   The inorganic waste is sewage sludge, the organic waste is sewage sludge, and the coalescence ratio of the sewage sludge and the sewage sludge is in the range of 10: 1 to 10: 5 by weight. The waste disposal apparatus according to claim 8.   The inorganic waste is waste sludge, the organic waste is sewage sludge, and the coalescence ratio of the waste sludge and the sewage sludge is in the range of 10: 2 to 10: 3 by weight. The waste disposal apparatus according to claim 8.   A fired pellet produced by the method according to any one of claims 1 to 7, or produced by the apparatus according to any one of claims 8 to 16.   A method for improving sediment quality, characterized in that the fired pellets according to claim 17 are sprayed on the drowned water sea bottom to regenerate the water sea bottom.

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