JPS6320197B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a biological treatment section that biologically treats organic wastewater by fluidizing carrier particles to which biofilms are attached in an aeration tank, and a biological treatment section that biologically treats organic wastewater by fluidizing carrier particles to which biofilms are attached in an aeration tank, and a biological treatment section that biologically treats organic wastewater by fluidizing carrier particles to which biofilms are attached in an aeration tank. The present invention relates to a fluidized bed wastewater treatment device that has an integral structure with a solid-liquid separation section that separates water and treated water.

Continuously flowing wastewater is brought into contact with carrier particles such as sand, activated carbon, granular plastic, etc. in a fluid state, and impurities such as organic matter and ammonia nitrogen in the wastewater are biologically treated, and sludge etc. are separated from the carrier particles. A fluidized bed sewage treatment device that purifies wastewater by separating solid matter from solid to liquid is already known from Japanese Patent Application Laid-open No. 53-46156, etc. The system uses gravity to separate solids such as sludge and treated water in a gravity-type sedimentation tank installed separately from the biological treatment equipment, so in order to improve the quality of the treated water, There is a problem that a long residence time is required, resulting in a large installation area and a large amount of equipment cost.In addition, the method shown in Figure 2 of the above publication is a system in which the wastewater after biological treatment is placed around the outer periphery of the fluidized bed. Since solid-liquid separation is performed by forming a sludge layer and trapping sludge in an upflow sedimentation tank, it exhibits superior solid-liquid separation performance compared to the above-mentioned device that separates solid-liquid using gravity. However, since the height and position of the sludge layer that is formed fluctuates due to changes in the quality of inflowing wastewater and changes in the amount of load, when extracting sludge from a predetermined position,
It is difficult to extract sludge at a specified concentration, and it is diluted by the treated water that accompanies the extracted sludge, which reduces the concentration of the extracted sludge and also causes biofilm to adhere to the bottom of the upflow settling tank. The carrier particles deposited and block the passage between the upward flow path and the downward flow path,
Stable treatment was no longer possible, and if sludge was not drawn out properly, the sludge layer would rise and the sludge would be entrained in the treated water, deteriorating the quality of the treated water.

The present invention was completed with the aim of providing a fluidized bed wastewater treatment device that solves the above-mentioned problems.
Hereinafter, the present invention will be explained in detail with reference to the illustrated embodiments.

Reference numeral 1 denotes a tank body whose upper part is formed into an enlarged diameter part 1a and whose lower part is formed into a funnel shape to improve the flow of carrier particles. An inner cylinder 2 is provided in the tank body 1 so that there is a required distance between its lower end opening and the tank bottom, and the upper end is located at a lower position than the upper end of the tank body 1. A cylindrical partition wall 3 surrounding the upper part is provided so that its upper end is located at a higher position than the upper end of the tank body 1. Furthermore, a slanted wall 4 surrounding the outside of the partition wall 3 and expanding upward is provided with its lower end extending upwardly. It is provided so as to be connected to the lower end of the diameter portion 1a. The partition wall 3 has a length such that its lower end is located near the bottom of the inclined wall 4. An upward flow settling section 11 is formed between the inclined wall 4 and the partition wall 3, the cross-sectional area of which gradually increases upward. Furthermore, a sludge storage section 12 having a sludge discharge port 6 at the bottom is formed between the inclined wall 4 and the enlarged diameter section 1a of the tank body 1 on the outside thereof. The tank body 1 is provided with an overflow receiving part 13 in its upper part to receive the effluent from the overflow port 5 located at a higher position than the upper end of the inclined wall 4, and a part in its lower part to send waste water to the lower part of the inner cylinder 2. Piping is provided in which an inlet 7 and a gas inlet 8 are located, and in this way, wastewater is introduced into the tank body 1 through the wastewater inlet 7, and aeration is carried out through the gas inlet 8, so that the inner cylinder is heated. 2, and a downward flow path 10 formed between the partition wall 3 or the tank body 1 and the inner cylinder 2, and the upward flow settling section 11. , a solid-liquid separation section B consisting of a sludge storage section 12 and an overflow receiving section 13 is formed. Incidentally, the inclined wall 4 has a gap with the partition wall 3 facing upward in order to improve the sludge trapping efficiency by reducing the flow velocity of wastewater flowing upward in the upflow settling section 11 to 1 to 5 m/Hr or less. Therefore, the upper end of the inclined wall 4 is located below the upper end of the tank body 1 so that the trapped sludge, which has grown in size, falls into the sludge storage section 12 by gravity. Although the position of the upper end of the inclined wall 4 may be fixed, the inclined wall 4 is designed to prevent the height of the sludge layer from changing due to changes in the quality of inflowing wastewater or the amount of load, thereby preventing the quality of treated water from deteriorating. It is preferable to adjust the height of the sludge layer by providing a slide gate 14 or the like on the entire circumference or a part thereof so that the height of the upper end surface of the sludge layer can be changed.
Furthermore, sludge is concentrated by gravity in the sludge storage section 12 formed between the inclined wall 4 and the tank body 1, but if the retention time is increased, the sludge concentration increases, but at the same time the risk of sludge rot increases. Therefore, it is necessary to adjust the number of sludge withdrawals or the volume of the sludge storage section 12. For this reason, it is preferable to divide the sludge storage section 12 into several sections by partitions 15 around the partition wall as necessary, and if it is divided in this way, the slope should be It is preferable to provide a slide gate 14 or the like on the wall 4 to adjust the height of the sludge layer in each chamber. In addition, carrier particles such as sand, activated carbon, or granular plastic are usually placed inside the tank body 1 and the inner cylinder 2, and waste water and gas such as air or oxygenated gas are introduced from the lower part of the inner cylinder 2 for aeration. In order to enhance the sludge capture function in the upflow settling section 11 and the sludge concentration function in the sludge storage section 12, chemical injection is performed to add an inorganic or organic flocculant, etc. A separate device may be provided.

With this structure, carrier particles such as sand, activated carbon, granular plastic, etc. are introduced into the tank body 1 and the inner cylinder 2, and wastewater is introduced from the wastewater inlet 7 located at the bottom of the inner cylinder 2. After the wastewater in the inner cylinder 2 reaches a predetermined water level, if gas is introduced from the gas inlet 8 and aeration is started, an upward flow will occur due to the air lift effect of the introduced gas, so this speed can be reduced. When the carrier particles are maintained at a sedimentation velocity of the carrier particles or higher, the carrier particles to which the biofilm is attached are entrained in the upward flow and ascend the upward flow path 9 in the inner cylinder 2 while coming into intense contact with waste water and gas. The waste water and carrier particles that have reached the upper end of the inner cylinder 2 are turned back here, descend through the downward flow path 10 between the inner cylinder 2 and the partition wall 3, or between the inner cylinder 2 and the tank body 1, and flow down the tank body. The downward flow that has reached the bottom of the flow path 1 turns back and becomes an upward flow again and ascends through the upward flow path 9. While circulating between the wastewater, impurities such as organic matter and ammonia nitrogen in the wastewater are taken up by the biofilm attached to the carrier particles, and some are oxidized and decomposed, while the other part is converted into sludge. This converted sludge will eventually peel off from the carrier particles, but
Since the specific gravity is lighter than the carrier particles, the exfoliated sludge is accompanied by wastewater and passes through the space between the partition wall 3 and the inclined wall 4 at a low speed and rises, forming an upward flow settling section 11 between the partition wall 3 and the inclined wall 4. When the sludge is efficiently captured and the interface of the captured sludge rises and reaches the upper end of the inclined wall 4, this sludge automatically flows out into the sludge storage section 12, and the sludge stored in the sludge storage section 12 When the sludge is concentrated to a required concentration by gravity, the sludge discharge port 6 at the bottom is opened and the concentrated sludge is discharged from the sludge discharge port 6. On the other hand, wastewater from which sludge has been removed in the upward flow settling section 11 after being subjected to biological treatment is passed through the overflow port 5 located at a higher position than the upper end of the inclined wall 4 provided at the upper end of the tank body 1 as treated water. leak. In addition, if the upper end position of the inclined wall 4 can be changed as in the above embodiment, the change in the quality of wastewater can be prevented even if the position of the sludge layer formed in the upward flow settling section 11 changes due to load changes. By adjusting the upper end position of the inclined wall 4, the concentration and amount of sludge drawn can be adjusted, and if the sludge storage section 12 is divided as appropriate, the sludge concentration can be adjusted by changing the residence time.

As is clear from the description of the above embodiments, the present invention provides a fluidized bed wastewater treatment apparatus in which an inner cylinder, a partition wall, and an inclined wall are provided in the tank body to form a biological treatment section and a solid-liquid separation section into an integral structure. After the sludge is captured and removed from the wastewater treated in the solid-liquid separation section in the upflow settling section, whose cross-sectional area gradually increases as it goes upwards, the sludge is transferred to the top of the inclined wall without any operations such as transfer. The sludge is allowed to fall into the sludge storage area, where it is concentrated by gravity and then discharged. This reduces the installation area of the treatment facility, reducing equipment costs, and the drawn sludge has a higher concentration and is more homogenized. In addition, it has various advantages such as being able to improve and stabilize the quality of treated water, and as a solution to the problems of conventional fluidized bed wastewater treatment equipment, it will greatly contribute to the development of industry. be.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention, and FIG. 2 is a plan view of the same. 1: tank body, 2: inner cylinder, 3: partition wall, 4: inclined wall,
5: Overflow port, 6: Sludge discharge port, 7: Wastewater inlet,
8: Gas inlet, 12: Sludge storage section.

Claims (1)

[Claims] 1. An inner cylinder 2 and a partition wall 3 that surrounds the upper part of the inner cylinder 2 and whose lower end is located near the lower part of the slope wall 4 are provided in a tank body 1 to which an upwardly expanding inclined wall 4 is connected to the upper end. Between the partition wall 3 and the inclined wall 4, there is an upward flow settling section 11 whose cross-sectional area gradually increases as it goes upward.
At the same time, a waste water inlet 7 and a gas inlet 8 are located below the inner cylinder 2, and an enlarged diameter part 1a is provided on the outside of the inclined wall 4. A sludge storage section 12 is formed to receive the sludge flowing out from the upflow settling section, and
A fluidized bed type wastewater treatment apparatus characterized in that an overflow port 5 is provided at a higher position than the upper end of the inclined wall 4 in the upper part of the enlarged diameter part 1a.