JP2000176497A - Method of removing organic matter in sludge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of removing organic matter in sludge which method excels in effect and forms no environmental pollution. SOLUTION: This method is provided with: a physical filtration process where water in the upper part only is diverted without extracting sludge on the bottom of the water and is passed through a filter bed having pore diameter of 1-100 μm to filter out organic suspended particles in this water; an aerating treatment and final filtration process where water that has undergone the physical filtration is subjected to aeration treatment by an aerator and is returned to the main flow and if necessary, after it is aerated, it is filtered again; and a backwashing treatment process where when the filter bed used in the physical filtration process is clogged to some extent, the water flow direction is reversed to wash out the organic suspended particles stuck on the filter bed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing organic matter in a wastewater, and more particularly to a method for removing organic matter in a wastewater by changing a biota in water to indirectly dilute and release organic matter contained in underwater soil. .

[0002]

2. Description of the Related Art Rivers, storage dams, lakes and ponds are used for
After a certain amount of time, eutrophication occurs, causing algae and plankton to propagate, most of which accumulate in the bottom in considerable sediment. The sediment is a mixture of inorganic matter and decaying organic matter such as sand and soil. It is roughly composed of an upper aqueous layer, a suspended oxide layer rich in elemental and air, and a concentrated non-flowable reduced layer below. And divided into

A river containing a mixture of these organic and inorganic substances,
The soil at the bottom of reservoirs, ponds, and aquaculture ponds is generally called a "hedro". Once such a skull accumulates in a reservoir, river, etc., it gradually becomes irrespective of water flow, water storage, or water quality itself. Problems emerge, for example, the quality of the water is polluted due to reduced runoff and storage. Until now, dredging and chemical treatments have been adopted to eliminate the "hello".

[0004] This dredging method directly removes the sludge, and can remove a considerable amount of sludge from the water bottom. However, the scale of the work is large and the cost is high, but the efficiency is not good. On the other hand, the chemical treatment method uses chemicals such as direct oxidants, such as chlorine,
It melts ozone, etc. into the mud and requires less construction equipment than the dredging method, but may destroy natural ecology and cause secondary environmental pollution.

[0005]

DISCLOSURE OF THE INVENTION In view of the above-mentioned problems in the conventional method of treating a sludge, an object of the present invention is to provide a method of removing organic substances in a sludge which is excellent in effect and does not form environmental pollution. And

[0006]

Means for Solving the Problems In order to achieve the above object, the present inventors have made it possible to increase the gradient of the concentration of organic matter in water without giving an opportunity to constantly remove organic matter and the like from water and settle to the bottom of the water. We focused on the point that can be made.

That is, according to the method for removing organic matter in a jellyfish of the present invention, only the upper water is diverted without extracting the jellyfish at the bottom of the water, and is passed through a filtration layer having a pore diameter of 1 to 100 μm. The step of performing physical filtration for removing the suspended particles by filtration, and returning the water that has passed through the physical filtration to the main stream by aeration with an aeration apparatus,
If necessary, the filtration process is performed again after the aeration process and the final filtration process.If the filtration layer used in the physical filtration process is clogged to some extent, the direction of the water flow is reversed and the filtration layer is attached to the filtration layer. Backwashing step of washing off the suspended organic particles.

[0008] In the present invention, it is more preferable that the oil and fat contained in the water is first adhered and filtered by an oil filter cotton before the water is filtered in the physical filtration step.

The present invention having the above-mentioned structure, by removing organic suspended particles in water by a physical filtration method, changes the biota of the lower skull and at the same time self-cleans the organic matter in the shirodo. By the conversion action, the organic substance is oxidized and decomposed from the reduced layer in the soil and dissolved in the water, and when the reduced layer releases the organic substance, the thickness of the soil is reduced, so that rivers, water marshes, water storage dams, etc. The organic matter contained in the bottom soil can be eliminated, and the water holding capacity can be relatively improved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be specifically described based on embodiments, but the present invention is not limited to these examples. As shown in FIG. 1, a relatively preferred embodiment of the present invention regulates water quality of reservoir dams, rivers, lakes and aquaculture ponds, and can remove their organic matter, and mainly includes the following steps.

(1) Physical filtration: Only the upper water is separated without extracting the bottom of the water bottom, and the separated water is subjected to a pore diameter of 1 to 100.
The suspended matter such as animal suspensions, plant suspensions, and organic suspended particles in the water is removed by filtration through a μm filtration layer to change the biota in the water. If the biota in this water changes, for example, the concentration will deviate from the equilibrium state, and the organic matter in the bottom of the bottom will be oxidatively decomposed and released into the water, and the organic matter in the bottom will gradually dissolve into the water. The water is converted or vaporized to form suspended particles, which are removed by filtration. As a result, almost only the inorganic sludge portion remains in the heddle, and the density increases and the volume decreases, whereby the flow rate of the river and the storage capacity of the storage dam can be improved.

(2) Aeration treatment and terminal filtration: The water that has passed through the above-mentioned physical filtration is aerated by an aeration equipment, and the content of air and oxygen in the water liquid is increased and returned to the water. Is recycled to filtration and aeration. Alternatively, filtration may be performed again to bring the water quality to a predetermined standard value.

(3) Backwashing treatment: After a certain period of the filtration layer used in the above step (1) has passed, a coarse animal suspension, a plant suspension, and an organic suspension attached to the filtration layer by the backwashing method. Organic silt such as suspended particles is washed away. These organic silt are filtered and dried to make a silt cake and used as fuel or directly incinerated in a closed incinerator.

On the other hand, with respect to the slime containing oils and fats, the oils and fats contained in the water solution are first adhered and filtered with oil filtration cotton before the water is physically filtered in the step (1). be able to.

FIG. 2 is an apparatus layout diagram of an embodiment when the method of the present invention is applied to river purification processing. (1) Build a weir: Build a weir 2 upstream of river 1
The river 1 is divided by the weir 2 into a water storage section 3 on the upstream side and a purified water section 4 downstream of the water storage section 3. The average flow rate of the river 1 is 240 tons / hour.

(2) Constructing a sewage area and an experimental area: A steel plate is used to surround a sewage area 5 and an experimental area 6 adjacent to the sewage area 5 and incompatible with each other at a location near the weir 2 at the river 1. One side of the sewage section 5 has a sewage inlet 6a communicating with the water storage section 4, and one side of the experimental section 6 has an overflow port 6a communicating with the purification section 4;
A number of pumps 7, 8 are installed in the experimental area 6.

(3) Construction of sewage treatment ponds and installation of each equipment: In this embodiment, five sewage treatment ponds 9, 10, 11, 12, and 13 each having a storage capacity of 20 tons are constructed. Among them, sewage treatment ponds 10, 11, 12, and 13 are provided on one side of the experimental area 6 at appropriate intervals along the flow of the river 1, and the equipment and facilities are disposed at appropriate intervals between the sewage treatment ponds 9, 10. , A silt dewatering device 15 for separating silt, an incinerator 16, and an ashes collection zone 17.

In the above, the sewage treatment pond 9 is used to introduce partial sewage in the sewage zone 5 and the experimental zone 6, and the sewage in the sewage zone 5 is supplied by the pumps 7 at a flow rate of 300 tons / hour. 9 and the water solution in the experimental area 6 is also injected by the pump 8 at a flow rate of 60 tons / hour. That is, an amount of 360 tons of water per hour comes into the sewage treatment basin 9 from the sewage area 5 and the experimental area 6 so that the sludge in the sewage area 5 and the experimental area 6 does not enter the sewage treatment basin 9. In order to control, the suction ports of the pumps 7 and 8 in the sewage area 5 and the experiment area 6 are wrapped with a stainless steel net basket and floated on the water surface. Only the surface water in the area 6 is extracted, and the sludge at the bottom is not extracted.

The sewage treatment pond 9 is provided with an oil filter cotton for removing the water. The oil filter cotton is not shown in the figure. While the incoming water liquid passes through the sewage treatment pond 9, most of the fats and oils contained therein are absorbed by the oil filtration cotton. Other contaminants, such as animal suspensions, plant suspensions, and organic suspended particles, which still contained therein, flowed into the filtration device 14 together with the water amount of 360 tons / hour, and were provided in the filtration device 14. By using a filtration layer (not shown) having a pore size of 1 to 100 μm, suspended matter such as animal suspended matter, plant suspended matter, and organic suspended particles flowing in from the sewage treatment pond 9 is removed by filtration.

The water that has passed through the filtration device 14 flows into the sewage treatment pond 10 at a flow rate of 360 tons / hour after the suspended matter contained therein has already been filtered out by the filtration device 14. In addition to having the aeration function, the sewage treatment pond 10 can more completely remove fats and oils that cannot be completely removed in the above steps. The water flowing from the filtration device 14 is subjected to aeration and degreasing treatment in the sewage treatment pond 10, and then flows into the sewage treatment pond 11 at a flow rate of 360 tons per hour. The sewage treatment pond 11 is mainly used as a buffer section for temporarily holding treated water, and a part of the water is discharged for 2 hours per hour.
At a flow rate of 40 tons, the water is merged into the water purification section 4 of the river 1, and the other part of the water is circulated to the experimental area 6 at a flow rate of 1200 tons per hour.

The water flow in the river 1 flows into the water storage section 3 upstream of the weir 2
Is an untreated water section, which contains impurities such as oils and fats, animal suspensions, plant suspensions, and organic suspended particles, and most of the water in the water purification section 3 downstream of the weir 2 is already described above. It is clean without any contaminants. That is, the water purification section 3
Most of the water has already been filtered and removed, and the concentration is extremely out of equilibrium. This promotes the decomposition of organic matter in the bottom of the water purification section 3 and allows it to be released into the water. And the water biota approaches the state of balance.

When the decomposition of organic substances in the slime is progressing, the present invention has another aeration step for promoting the activation of microorganisms which dissolve in water and cannot be removed by filtration.
It is possible to further promote the decomposition efficiency of the sludge. Also,
While the purifying water purifying section 4 continues the decomposition and release action as described above, the organic sludge portion gradually decreases, the bottom soil thickness of the entire riverbed becomes thinner, and the relative The amount of drainage increases.

The reason why a part of the water in the sewage treatment pond 11 is caused to flow into the water purification section 3 at an amount of 240 tons per hour is that the water flow rate of 240 tons / hour is caused by the water flow flowing into the sewage area 5 of the storage section 3. This is because it corresponds to speed. With such a design, the flow of the river is not interfered and the flow is not stagnated. On the other hand, the other water in the sewage treatment pond 11 is 1
At a flow rate of 20 tons / hour, it flows into the experimental zone 6, which is used not only to store the water that has already been purified, but also to observe the improvement of the river 1 water quality.

The above description relates to the fact that after the river 1 has been treated by the method of the present invention, the water quality has been relatively improved and the water has been circulated to the water purification section 4.
Although a large amount of silt accumulates on the filtration device 14 and reduces the filtration effect, the sewage treatment pond 12 temporarily holds the water discharged from the sewage treatment pond 11, so that the sewage treatment The water in the pond 12 can be introduced into the filtration device 14 and used for backwashing. Then, the sludge adhering to the filtration layer inside the filtration device 14 such as animal suspensions, plant suspensions, and organic suspended particles is backwashed into the sewage treatment pond 13 which is not connected to any pond. The sludge dewatering machine 15 dewaters the sludge cake to produce a sludge cake, which is sent to an incinerator 16 for incineration.

It should be noted that the main components of the organic substance of the shell are nitrogen and carbon, and the nitrogen and carbon perform a conversion action when microorganisms in the shell are decomposing the organic substance. It is also a necessary consumable energy element. Fig. 3 relates to the conversion of nitrogen compounds in the slime, which can release ammonia and nitrate groups during the conversion process, and the ammonia and nitrate groups are nutrients for the survival of algae. It is the main food required for the survival of the fish, and the spatula can interpret ammonia and nitrate groups, but the ammonia and nitrate groups are mainly obtained from organic suspended particles in water.

That is, under the condition that the ecology is in an almost equilibrium state, it is impossible to interpret ammonia and nitrate groups from soil. However, the water that has undergone the above-mentioned treatment step is already relatively low in fats and oils and contains almost no organic suspended particles such as animal suspensions and plant suspensions. Since the main source is removed and the biota in the water purification section 4 deviates from the equilibrium state, an action toward the equilibrium state is effected, and ammonia and nitrate groups are gradually interpreted from the middle of the slime. With the help of the aeration step during the decomposition process, the microorganisms in the water are activated and oxidative decomposition is promoted, and the water exhibits aerobic bacterial dominant ecology, and the reduced layer at the bottom gradually decomposes. The organic suspension particles are released to provide a source of algae survival and bring the biota in the water purification section 4 closer to equilibrium.

As can be seen from the above description, the present invention mainly removes the organic suspended particles in the aqueous liquid of the wastewater by a physical filtration method, destroys the biological flora of the wastewater, and at the same time converts the wastewater contained in the wastewater itself. By the action, the organic matter is decomposed from the reduced layer in the soil and released into water, and when the reduced layer releases the organic matter, the thickness of the soil gradually decreases, thereby increasing the drainage of the river and tidying the river. The effect can be obtained.

The river treated according to the present invention is
Since the organic matter in the soil is gradually interpreted and the rate of increase in the thickness of the entire hedder layer becomes extremely slow, the construction interval for large-scale dredging work is effectively prolonged, and the bottom sediment removed by dredging is effectively removed. Since most of the mud is inorganic, it can be advantageously recovered and used as a building fill soil.

The present invention can be used not only as a means of improving river water quality, but also for purifying the water quality of ponds and lakes. In order to more clearly support the purification effect of the present invention,
A control test was performed on two ponds having an area of 293.4 tsubo and a water depth of 120 cm, and as shown in FIGS. 4 and 5, one of the ponds (hereinafter referred to as a processing example, the curve of which is represented by (a)). The water in the pond is circulated and filtered for one hour by the purification method of the present invention every day, and the water in the other pond (hereinafter referred to as a control, the curve of which is represented by (b)) is replaced at least once a week. An extraction test was performed once a week for each of the pH value and NH4 -N concentration in both ponds as parameters, and the measured pH value is plotted against time in the curve diagram of FIG. From FIG.
It can be seen that the treatment example of the present invention can make the pH value in the pond more neutral than the control example of water purification using a simple water exchange method. The NH4 -N of the processing example of FIG.
As can be seen from the curve against the N concentration and time, it can be seen that the treatment example has a lower NH4 -N concentration than the control example. That is, as shown in FIG. 4 and FIG. 5, when the water quality of the pond is purified by the present invention, the effect is more excellent than the conventional method of changing water, and therefore greatly contributes to the stability of the water and the growth of the culture. can do.

[0030]

As described above, according to the present invention, water and fat, organic suspended particles such as animal suspensions and plant suspensions in a water solution of a shellfish are removed by a physical filtration method to remove water. At the same time as changing the biota, the organic substances in the sludge are released into the water without interruption, and only the inorganic portion remains from the release of the organic substances in the soil, reducing the thickness of the sludge, thereby reducing the thickness of rivers and reservoir dams. Organic matter can be removed to increase the water capacity.

[Brief description of the drawings]

FIG. 1 is a flow sheet of a relatively preferred embodiment of the present invention.

FIG. 2 is a schematic layout diagram of an apparatus in which the method of the present invention is applied to river processing.

FIG. 3 is a schematic diagram of a conversion process of a nitrogen compound in a stove.

FIG. 4 is a graph showing the relationship between pH value and time when water is treated in the present invention and another control example.

FIG. 5 is a graph showing the relationship between NH 4 —N concentration and time when water is tidyed in the present invention and another control example.

[Explanation of symbols]

 1 ... river, 2 ... weir, 3 ... water storage section, 4 ... water purification section, 5 ... sewage inlet, 6 ... experimental area, 6 ... overflow port, 7, 8 ... pump, 9, 10, 11, 12, 13 , 14 ... Sewage treatment pond, 15 ... Sludge dewatering machine, 16 ... Incinerator, 17 ... Ashaku collection zone.

Claims (2)

[Claims] 1. A physical filtration step in which only the upper water is diverted without extracting the bottom of the water bottom, and the organic suspension particles in the water are removed by filtration through a filtration layer having a pore size of 1 to 100 μm; The water after the physical filtration is aerated by an aeration equipment and returned to the main stream, and if necessary, the aeration treatment and the final filtration step of filtering again after the aeration treatment are used in the physical filtration step. A step of reversing the direction of water flow when the filter layer is clogged to a certain extent to wash out the suspended organic particles attached to the filter layer. 2. The removal of organic matter in a stove according to claim 1, wherein the oil and fat contained in the water is adhered and filtered by an oil filter cotton before filtering the water in the physical filtration step. Method.