JP3973294B2 - Shell Methane Fermentation Processing Equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shellfish methane fermentation treatment apparatus, and more particularly to a biological treatment apparatus capable of treating a large amount of shellfish in a manner harmonized with the environment.
The shellfish methane fermentation treatment apparatus of the present invention is discarded from shellfish removed from seawater used for cooling equipment and processes in thermal power plants, nuclear power plants, chemical plants, etc., and from fishery-related food factories, etc. It can be used effectively for the treatment of shellfish.
[0002]
[Prior art]
For example, in a thermal power plant, many power generation problems occur due to a lack of cooling water caused by breeding and dropping of shellfish algae in the waterway. Shells grown and killed in the intake channel accumulate in the intake pump room, or a large amount of grown shells fall and adhere to the screen to block it, reducing the amount of water due to abnormal increase in pump power and decrease in pump capacity Has been experienced.
[0003]
There are many mussels, oysters, barnacles, etc. that adhere to them, and as a countermeasure, they are scraped off by human power and then discarded. For disposal, incineration or landfill treatment is used, and it is difficult to separate the shell from the shellfish, so that it is treated as it is.
[0004]
[Problems to be solved by the invention]
Shellfish algae treatment is substantially shellfish treatment, and conventional shellfish treatment methods have the following problems.
[0005]
A. In the case of incineration of shellfish (a) Since shellfish contains more than 80% of water, a large amount of fuel is required for incineration, and the running cost is high.
(B) Since a large amount of fuel is burned, a large amount of carbon dioxide, which causes global warming, is emitted. In addition, when the shell is burned without separation, the calcium carbonate component of the shell is decomposed, and a large amount of carbon dioxide immobilized therein is discharged.
(C) Contaminants such as dioxins may be generated.
[0006]
B. In the case of landfill treatment of shellfish (d) Since the organic matter was altered, there were problems with odor and hygiene.
(E) It is difficult to secure landfill.
(F) The landfill is insufficient to support and it is difficult to use the site afterwards.
[0007]
Accordingly, an object of the present invention is to provide a shellfish methane fermentation treatment apparatus that decomposes shellfish and collects shells as calcium carbonate material.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present inventor has focused on the following points, and has obtained knowledge that these points of interest are effective processing elements for shellfish processing.
(1) If shellfish can be automatically separated into shells and shellfish, only shells can be recovered for useful purposes.
(2) If the sorted shellfish is made into a paste that is substantially free of solids, it can be decomposed to the extent that it can be discharged into sewage by methane-fermenting bacteria, and problems associated with conventional incineration and landfilling The point can be solved.
(3) If biogas such as methane produced as a by-product in the process of decomposition by methane fermentation is recovered as fuel, the cost of the shell processing process can be reduced.
In order to confirm the above points, the following experiment was conducted.
[0009]
[Experiment 1] Automation of separation of shell and shell meat A high-pressure separator 2 having a pressurizing chamber 2a and a gap 2b in a cylinder 2c as shown in FIG. 2 was prepared. That is, the upper piston 2d and the lower piston 2e are provided in a cylinder 2c having an inner diameter of 150 mm, and the space inside the cylinder 2c between the pistons 2d and 2e is used as a pressure chamber 2a for shell crushing. Both pistons 2d, 2e were connected to the hydraulic unit 2g, and the upper and lower pistons 2d, 2e were moved and pressurized to the pressurizing chamber 2a. A 0.7 mm gap 2b was provided between the piston and the inner peripheral surface of the cylinder 2c in order to paste shellfish.
[0010]
A 50 kg mussel was put into the pressurizing chamber 2a, and a pressure of 250 kg / cm ² was applied by the hydraulic unit 2g. As a result, 34 kg of shellfish paste was obtained and 16 kg of finely crushed shells were obtained. Almost no shell-like material was found in the shellfish paste. Slight organic matter (shells and seaweeds) was mixed in the ground shell.
[0011]
[Experiment 2] 3 kg of shell and 15 liters of water obtained in Shell Cleaning Experiment 1 are placed in a washing tank 3a with a stirrer having a capacity of 50 liters, and in this case caustic soda (NaOH) so that it becomes 0.01 N (specified concentration) After adding the alkaline aqueous solution Z, the mixture was stirred and washed for 1 hour. Table 1 shows the weight of the shell after washing. The addition of the alkaline aqueous solution Z dissolves the protein and promotes the peeling of organic matter such as shells from the shell, and further increases the alkalinity in the bioreactor 4 described below, thereby interfering with foreign substances. This is to increase the size and to stabilize methane fermentation. However, in the present invention, the addition of the alkaline aqueous solution Z is not an essential requirement.
[0012]
The washing experiment was performed three times. On average, about 8% by weight of organic matter was adhered to the shells immediately after the separation in Experiment 1. However, no adhesion of organic matter was observed on the shell after washing in Experiment 2 at any time.
[0013]
[Table 1]
First washing experiment Weight before washing 15.2kg Weight after washing 14.3kg
Second washing experiment Weight before washing 15.0kg Weight after washing 13.5kg
3rd washing experiment Weight before washing 15.0kg Weight after washing 14.0kg
[0014]
[Experiment 3] Separation of shell and attached organic matter 30 kg of crushed shell obtained by the method of Experiment 1 and 60 kg of water are placed in a washing tank 3 a with a stirrer as shown in FIG. The slurry (solid-liquid mixture) obtained by adding caustic soda (NaOH) and stirring for 1 hour is sent to the solid-liquid separator 3b consisting of a liquid cyclone as shown in the figure, and the solid (shell) and liquid (adhesive organic matter are removed). Containing washing water). The hydrocyclone used in this experiment was a standard hydrocyclone with a cylindrical part diameter of 15 cm. The slurry flow rate was 6 liters / minute, and the ratio (Qo / Qf) between the upstream flow rate (Qo) and the downstream flow rate (Qf) of the cyclone was 5. The experimental results are shown in Table 2. The true specific gravity of the washed shell was 1.4.
[0015]
[Table 2]
Downstream of cyclone: shells and small amount of water Total 46 kg (no solid organic matter observed) Upstream of cyclone: Water containing solid organic matter 44 kg (no shell observed)
[0016]
[Experiment 4] Decomposition experiment 1 of mussel paste such as shellfish paste Diluted mussel shell paste with the same amount of water was used as the raw waste liquid, and the methane fermentation experiment was conducted using bioreactor 4 in FIG. I did it. 3 and 4, as the bioreactor 4, a fixed bed type in which a filter bed 4a composed of four glass fiber carriers 4b having a diameter of 30 mm and a length of 600 mm is packed in a reaction tank having an effective volume of 3 liters. I used one. As microorganisms on the carrier 4b, sludge containing high-temperature methanogens active at 55 ° C. was used. After putting 3 liters of sludge with VSS (organic solid content concentration, generally indicating microbial concentration) into 8,000 mg / liter into the bioreactor 4 and heating to 55 ° C, the raw waste solution is gradually added to the bioreactor. 4
[0017]
The raw liquid C0Dcr (chemical oxygen demand) was 30,000-40,000 mg / liter, and its B0D (biological oxygen demand) was 25,000-35,000 mg / liter. In 30 days after the start, because C0D volume load fermentation state becomes the 16kgC0D / m ³ days has stabilized, and the operation as it is for 60 days. The treated water quality was 4,000 to 6,000 mg / liter for C0Dcr and 3,000 to 4,000 mg / liter for B0D. The average removal rate over 60 days was 85% for C0Dcr and 88% for B0D.
[0018]
Biogas was generated on average 20 liters per liter of raw waste liquid, and the average composition of methane in biogas was 71%.
[0019]
The present invention has been completed based on the knowledge obtained in the above experiments.
[0020]
Referring to the embodiment shown in FIGS. 1 and 2, a shellfish methane fermentation treatment apparatus 1 according to the present invention includes a pressurized chamber 2a for pulverizing shells and a gap 2b for forming shellfish paste connected to the pressurized chamber 2a. high pressure fractionation unit 2 having a pressurizing means (hydraulic unit 2g of FIG. 2), and the remaining shellfish flesh solution R the cleaning water W remaining shellfish meat dropped wash the cleaning water W on the grinding shell L from the high pressure sorter 2 A shell washing tank 3a with a stirrer, a solid-liquid separator 3b for separating the crushed shell from the remaining shellfish solution R, and a vibrating sieve 3d for washing the separated crushed shell with washing water W, and separating the solid and liquid A crushed shell washing unit 3 that uses part of the remaining shellfish solution R from the apparatus 3b and washing water W from the vibrating sieve 3d by returning it to the shell washing tank 3a , and a shellfish paste P from the high-pressure separator 2; A biological reaction tank 4 for subjecting the remaining portion of the remaining shellfish solution R from the solid-liquid separator 3b to methane fermentation treatment It is prepared.
[0021]
Preferably, the high-pressure separator 2 includes a pair of pistons 2d and 2e, and a cylinder 2c and a cylinder 2c that define the pressurizing chamber 2a between the pistons 2d and 2e at a predetermined pressurizing position. A recess 2f on the periphery of the piston 2e that forms the gap 2b for pasting between the inner peripheral surface, a pressurizing means 2g for driving the pistons 2d and 2e, and a recess 2f of the piston 2e at a predetermined pressurizing position shellfish meat outlet 2h of the site through the wall into the opening on the cylinder 2c peripheral wall, and crushed shells which open through the wall into an intermediate portion of a predetermined payout position of both pistons 2d, 2e in the cylinder 2c on the peripheral wall Discharge port 2i is provided.
[0022]
More preferably, Ru adding an alkali aqueous solution Z so that the cleaning water W of the shells wash tank 3a 0.01 ~ 0.05 N (normal concentration).
[0023]
DETAILED DESCRIPTION OF THE INVENTION
The operation of the methane fermentation treatment apparatus for shellfish according to the present invention will be described with reference to the embodiment of FIGS.
The shellfish to be treated is put into the washing hopper 15, sprayed with clean water C from above to wash the shellfish, and the washing wastewater Y is allowed to flow into the drainage channel. The washed shellfish is sent to the high-pressure separator 2 by a screw conveyor.
[0024]
In the embodiment of the high-pressure separator 2 shown in FIG. 2, the pressurizing position of the pressurizing chamber 2a in the cylinder 2c when the shell is crushed is predetermined as shown by the solid line position, and the crushed shell L is sent out. The payout position is determined in advance as indicated by the dotted line position. Shells from the washing hopper 15 are filled into the high-pressure separator 2 through the shell inlet 2k that opens toward the pressurizing chamber 2a at the pressurizing position.
[0025]
When a sufficiently large pressure is applied to the pressurizing chamber 2a from the hydraulic unit 2g through the upper piston 2d and the lower piston 2e, the non-fluid shell is crushed in the pressure chamber 2a by the pressure from both pistons 2d and 2e. And crushed shell L. Only the shellfish with fluidity becomes shellfish paste P and flows into the minute gap 2b and is discharged from the outlet 2h.
[0026]
Thereafter, the pressurization chamber 2a is moved to the discharge position by the movement of the upper piston 2d and the lower piston 2e, and the crushed shell L is discharged through the discharge port 2i opened to the pressurization chamber 2a at this position. In the illustrated example, a delivery piston 2j is provided at a portion on the cylinder 2c facing the delivery port 2i, and the delivery piston 2j delivers the crushed shell L from the cylinder 2c to the delivery port 2i. In this way, the shell and the shell meat are separated and sent separately to the discharge port 2i and the outlet 2h, respectively.
[0027]
The compression in the pressurizing chamber 2a is performed at a pressure of 200 to 250 kg / cm ² by, for example, the hydraulic unit 2g. In the case of the illustrated example, the minute gap 2b, which is the clearance between the cylinder 2c and the lower piston 2e, is 1 mm or less as a reference, and is variable according to the specification of the separation state. The diameter of the cylinder 2c is determined by the amount of shells to be separated, and the separation treatment amount increases as the diameter increases.
[0028]
Since the separated crushed shell L is attached with a small amount of remaining organic matter such as shellfish and seaweed, the crushed shell L from the dispensing port 2i is washed with water by the washing unit 3. As shown in FIG. 1, the washing unit 3 includes a shell washing tank 3a for washing the remaining shellfish on the crushed shell L into the remaining shellfish solution R, and a solid-liquid separator for recovering solids from the remaining shellfish solution R. and 3b, provided with vibrating screen 3d washing the separated milled shells with wash water W. Put the crushed shell L and the wash water W from the separator discharge port 2i into the washing tank 3a , stir with a stirrer etc., and wash off the organic matter such as the remaining shellfish on the crushed shell L to the new wash water W first. The water is made into the remaining shellfish solution R. Preferably, an alkaline aqueous solution Z such as caustic soda (NaOH ) is added to the washing water W ( residual shell meat solution R ) so as to have a concentration of 0.01 to 0.05 N so as to improve the washing efficiency and the subsequent stabilization of methane fermentation. . The longer the cleaning time, the better, but one hour is sufficient.
[0029]
The residual shellfish solution R containing the crushed shell L after washing is added to the solid-liquid separator 3b to separate and collect the crushed shell L of the solid content. An example of the solid-liquid separator 3b is a liquid cyclone. Since the crushed shell L discharged from the solid-liquid separator 3b as a solid content is accompanied by a small amount of organic-containing washing water, the organic matter is completely removed from the crushed shell L by pouring it through a vibrating sieve 3d while pouring fresh washing water W. To remove. Since the crushed shell L recovered in this way is made of calcium carbonate, it can be used as a soil neutralizer or the like. The water dropped from the sieve 3d , that is, the water accompanying the crushed shell L from the solid-liquid separation device 3b and the washing water newly injected by the sieve 3d are returned to the washing tank 3a by the washing water pump 3e and used for washing the shell. Further, as shown in FIG. 1, solid-liquid solids return a portion of the remaining shellfish flesh solution R after separation into the wash tank 3a in the separation device 3b, washing tank 3a and the solid-liquid separation device 3b by pulverizing shells circulation pump 3c Circulate between.
[0030]
Of the shellfish paste P discharged from the outlet 2h of the high-pressure separator 2 and the remaining shellfish solution R from which the crushed shell L was separated by the solid-liquid separation device 3b of the washing unit 3, other than the part returned to the washing tank 3a Both the remaining part and the remaining part are poured into the methane fermentation tank 4 as slurry S. There are many kinds of biological fermenters 4 also called bioreactors. For example, a cylindrical filter 4b illustrated in FIGS. 3 and 4 is regularly packed vertically to form a fixed filter bed 4a. The carrier 4b carries methane fermentation bacteria, and efficiently decomposes organic substances in the shellfish paste P and the remaining shellfish solution R. The slurry S is preferably circulated in the methane fermentation tank 4 upward or downward by, for example, a slurry circulation pump 8 in order to disperse the solid content and to make the fermentation temperature uniform. However, the biological reaction tank 4 used in the present invention is not limited to the one using the fixed filter bed 4a and the cylindrical carrier 4b.
[0031]
The inventor has experimentally found that the organic matter concentration of the treated water after the methane fermentation is such that it can be reduced to a regulation value or less for sewage by a conventional secondary treatment, for example, a secondary treatment of activated sludge. It was. In the embodiment of FIG. 1, an immersion film 10 is used as the secondary treatment.
[0032]
Therefore, the treated water of the shellfish methane fermentation treatment apparatus according to the present invention can be discharged into sewage or river after secondary treatment with conventional activated sludge and the like.
[0033]
In short, according to the present invention, more than 80% of organic matter is decomposed into biogas by shellfish and attached seaweeds by anaerobic microorganisms typified by methanogens. The remaining organic matter is also decomposed by the aerobic microorganisms of the activated sludge. Since shells and shellfish are separated prior to biological treatment, the bioreactor is not blocked by shells and stable fermentation is achieved. It can be used effectively because it also cleans shells. That is, the present invention decomposes shellfish and enables recovery of shellfish as calcium carbonate.
[0034]
Therefore, “the provision of a methane fermentation treatment apparatus for shellfish that decomposes shellfish and collects shellfish as a calcium carbonate material” that is an object of the present invention can be achieved.
[0035]
【Example】
In the embodiment of the present invention shown in FIG. 1, in the shell washing unit 3, a part of the remaining shellfish solution R after the solid content is separated by the solid-liquid separation device 3b is sent to the grinder 5 and the remainder is washed tank 3a. Then, the crushed shell L is circulated between the washing tank 3a and the solid-liquid separator 3b by the crushed shell circulation pump 3c to thoroughly clean the crushed shell L.
[0037]
Since the residual shellfish solution R after separating the crushed shell L as a solid content in the solid-liquid separator 3b also contains particles that are not suitable for decomposition in the biological reaction tank 4, these particles are preferably used to promote fermentation. Is pulverized by a pulverizer 5. Although finer pulverization is better, it is preferably 100 microns or less. An example of the pulverizer 5 for this purpose is a stone mill type. The slurry S from the pulverizer 5 is sent to the slurry tank 6 and sufficiently mixed with the shellfish paste P from the high-pressure separator 2.
[0038]
The slurry S once stored in the slurry tank 6 is put into the biological reaction tank 4 by the slurry supply pump 7 and subjected to organic matter decomposition treatment by methane fermentation. The biological reaction tank 4 used in the present invention is sufficient if it decomposes the organic matter in the shellfish paste P as the organic matter in the slurry S and the remaining shellfish solution R by methane fermentation. Preferably, a fixed bed type in which a cylindrical carrier 4b shown in FIG. 4 is regularly packed in the vertical direction is used. The carrier 4b shown in the figure is obtained by supporting a hollow cylinder 4e on a frame 4g. Preferably, the hollow cylinder 4e is formed by a porous peripheral wall 4f made of glass fiber or carbon fiber. The carrier 4b is used by supporting a high-temperature methanogen that ferments at 50 to 60 ° C. to efficiently treat the slurry S. The fermented liquor, that is, the slurry S, is preferably circulated in the biological reaction tank 4 upward or downward by the slurry circulation pump 8 in order to disperse the solid content and make the fermentation temperature uniform.
[0039]
The waste liquid after the decomposition treatment by methane fermentation is treated to a level equal to or lower than the regulation value for sewage by a conventional secondary treatment such as an aerobic treatment by activated sludge or a submerged membrane treatment, and discharged as sewage or rivers as treated water E.
[0040]
Biogas generated during methane fermentation in the biological reaction tank 4 can be used as a heat source for the hot water boiler, and the obtained hot water can be used for heating the biological reaction tank 4 or general hot water supply. Since biogas contains a small amount of hydrogen sulfide, it is desulfurized with a desulfurizer 13 made of iron oxide or the like for preventing corrosion and ensuring safety. When used as fuel for a boiler or the like, it is convenient for fuel control or the like to temporarily store biogas in a small water-sealed gas holder 14.
[0041]
【The invention's effect】
As described above, the shellfish methane fermentation treatment apparatus according to the present invention has the following remarkable effects because the shellfish is decomposed by methane fermentation after separating the shell into shells and shellfish.
[0042]
(I) Shellfish can be processed at low running cost because shellfish is processed by energy-saving and resource-saving biological treatment using methane fermentation.
(B) Since it is a non-combustion type, carbon dioxide does not increase and there is no generation of pollutants such as dioxins.
(C) Since the shellfish is completely separated from the shell, the shell after separation can be used as a soil conditioner or a cement extender.
(D) Since high-temperature methane fermentation can be used, a highly efficient and small shell processing apparatus can be provided.
(E) It is possible to recover methane gas generated as a by-product as fuel, to use resources and reduce the cost of the shell processing apparatus.
[Brief description of the drawings]
FIG. 1 is an explanatory view of an embodiment of the device of the present invention.
FIG. 2 is an explanatory diagram of an embodiment of a high-pressure separator used in the present invention.
FIG. 3 is a diagram showing a configuration of a biological reaction tank used in the present invention.
FIG. 4 is an explanatory view of a microorganism carrier in the reaction tank of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Shell methane fermentation processing apparatus 2 ... High pressure sorter 2a ... Pressurization room
2b ... Gap 2c ... Cylinder
2d ... Upper piston 2e ... Lower piston
2f… Recess 2g… Hydraulic unit
2h… Outlet 2i… Discharge outlet
2j ... Dispensing piston 2k ... Shell inlet 3 ... Shell cleaning unit 3a ... Cleaning tank
3b… Solid-liquid separator 3c… Crushing shell circulation pump
3d ... Vibrating sieve 3e ... Washing water pump 4 ... Biological reaction tank 4a ... Filter bed
4b ... carrier 4e ... hollow cylinder
4f ... Porous peripheral wall 4g ... Frame 5 ... Crusher 6 ... Slurry tank 7 ... Slurry supply pump 8 ... Slurry circulation pump 9 ... Secondary treatment tank 10 ... Immersion membrane
11… Aeration blower 12… Processed water pump
13… Desulfurizer 14… Gas holder
15 ... Washing hopper C ... Washing water E ... Treated water G ... Biogas L ... Crushed shell P ... Shellfish paste R ... Residual shellfish solution W ... Washing water Y ... Washing drainage Z ... Alkaline aqueous solution

Claims (5)

A high-pressure separator having a pressurizing chamber for crushing shells, a gap for forming shellfish paste connected to the pressurizing chamber, and pressurizing means ;
A shell washing tank with a stirrer that uses the washing water to wash away residual shellfish on the ground shell from the high-pressure separator into the washing water, and a solid-liquid separation to separate the ground shell from the residual shellfish solution An apparatus and a vibrating sieve for washing the separated crushed shell with washing water, and returning a part of the remaining shellfish solution from the solid-liquid separator and the washing water from the vibrating sieve to the shell washing tank. A shell methane fermentation treatment apparatus comprising a bioreactor for methane fermentation of a crushed shell washing unit to be used , and a shellfish paste from a high-pressure separator and a remaining portion of a remaining shellfish solution from a solid-liquid separator. 2. The processing apparatus according to claim 1, wherein the high-pressure separator has a pair of pistons therein, a cylinder defining a pressurizing chamber between predetermined pressurizing positions of both pistons, and an inner peripheral surface of the cylinder. A recess on the peripheral edge of the piston that forms the gap for pasting, a pressurizing means for driving the piston, and a portion on the peripheral wall of the cylinder that faces the concave portion on the peripheral edge of the piston at the predetermined pressure position. A shellfish methane fermentation treatment apparatus comprising a shell outlet that opens and a discharge port for a crushed shell that opens through the peripheral wall at an intermediate portion of a predetermined discharge position of both pistons on the cylinder peripheral wall. The processing apparatus of Claim 1 or 2 WHEREIN: The methane fermentation processing apparatus of the shellfish which adds alkaline aqueous solution so that it may become 0.01-0.05N (normal density | concentration) to the washing water of the said shell washing tank. The processing apparatus according to any one of claims 1 to 3, further comprising a pulverizer for finely pulverizing a solid content in the remaining shellfish solution after separation of the crushed shell, and the shellfish paste and the finely pulverized powder from the high-pressure separator. A methane fermentation treatment apparatus for shellfish obtained by subjecting the remaining shellfish solution to methane fermentation treatment in the biological reaction tank. In any of the processing apparatus of claims 1 4, methane fermentation treatment apparatus of shellfish comprising providing a gas holder for biogas produced in the biological reactor as a by-product.

Images