JPH0669553B2 - Sewage purification method and equipment - 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 equipment for purifying a large amount of contaminated water such as polluted inner bays, closed sea areas, lakes and marshes. More specifically, it fixes microorganisms inside or on one side of a stone embankment. A corridor with polluted water inside or a polluted water purification facility equipped with a catalytic oxidation unit filled with a liquefiable contact carrier and having a biological purification function by internal or external aeration. The present invention relates to a method for treating polluted water by installing the same inside and passing the polluted water through the facility, and a purification facility.

[0002]

2. Description of the Related Art As a method for biologically purifying organic substances and inorganic substances in sewage and factory wastewater, the activated sludge method, sprinkling filter method, rotating disk method, etc. have been well known. These methods are water treatment technologies that artificially create the environmental conditions necessary for the growth of microorganisms, make the most of the ability of microorganisms to decompose organic substances, and purify sewage.

However, such a water treatment facility includes a pretreatment process and a sludge treatment process, and requires a vast amount of land and construction cost, so that a large amount of wastewater such as polluted inner bays, closed sea areas, lakes and marshes is treated. It is an inefficient system to do.

Therefore, the following purification system has been devised with the aim of positively utilizing the self-cleaning action by the attached organisms near the breakwaters and revetments.

In this system, natural stones or porous artificial stones 1 are piled up in the sea as shown in FIG. 2 to form a permeable dam body, and when polluted seawater permeates this dam body many times. By the attached organisms such as barnacles and oysters attached to the levee body, organic substances in seawater are taken up by the organisms to be purified.

[0006]

DISCLOSURE OF THE INVENTION The present invention is a new purification system in which the idea of the catalytic oxidation method used as water treatment equipment is introduced into the above-mentioned permeable levee body. The problem is to purify the polluted inner bay and closed water area.

[0007]

Means for Solving the Problems The present invention is to achieve the above-mentioned object, and a catalytic oxidation facility capable of maintaining a high concentration of a microorganism decomposing an organic substance is incorporated into a permeable levee to realize a natural It makes the most of the food chain.

That is, a catalytic oxidization section filled with a contact carrier capable of immobilizing microorganisms was provided inside or on one side of a masonry embankment constructed with split stone, etc., and a biological purification function was provided by internal or external aeration. A levee having a water-permeable purification facility is installed in a polluted water area or a passage into which polluted water is drawn, and the polluted water is treated by passing the polluted water from one end to the facility.

That is, the purpose of the permeation type purification method proposed by the inventors is to play a central role in removing organic matters, particularly in the permeation type embankment in which natural stones or porous artificial stones that have been conventionally devised are piled up in the sea. The purpose of this is to provide a catalytic oxidation part for keeping the microorganisms having the above-mentioned concentration at a high concentration, and to improve the purification level and the purification efficiency by the activity of the high concentration microorganisms.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on an embodiment with a dam body having the embodiment purification equipment shown in FIG. In the figure, 1 is a masonry embankment, 2 is a contact carrier, 3 is a contact oxidation part, 4 is a sludge accumulation part, 5 is an underwater agitation diffuser, and 6 is a boardwalk.

Of these levees, the catalytic oxidation part plays an important role in decomposing / removing organic substances, and is constituted by a contact carrier capable of adhering / holding a high concentration of microorganisms decomposing organic substances. As the contact carrier, those used for treating sewage and industrial wastewater are usually used. For example, a honeycomb tube, gravel, a net, a plastic carrier, or the like is appropriately used.

The inventors have found that, among these carriers, the string-shaped carrier is particularly excellent.

In general, it is preferable that the contact carrier has a large specific surface area so that microorganisms can be maintained at a high concentration. Further, since the method of the present invention constructs a dam body in seawater or water having high biological productivity, it is preferable not to provide a mechanical article such as a backflow device and pipes. For example, when an air diffuser for supplying air and a diffuser are installed in the sea, barnacles or the like adhere to the air diffuser and the diffuser during periods of high biological production, causing problems such as clogging and clogging of the air diffuser and diffuser. Therefore, it is preferable that the carrier used also has a large porosity and does not require backwashing of the catalytic oxidation part. A particularly preferable string-shaped carrier is a string-shaped contact material having a large number of delicate and tough radial ring-shaped carriers, and has a large track record in septic tanks and wastewater treatment facilities. This carrier is characterized by a large specific surface area and a high porosity.

The inventors have conducted comparative experiments using gravel, a plastic carrier, a string-shaped carrier and the like, and confirmed the superiority of the string-shaped carrier.

In this comparative experiment, the string-shaped carrier was
Many protozoa and metazoans, which are rarely seen in other carriers, were found, and it was confirmed that the biota were diverse. It is conventionally known that the more diverse the biota, the better the quality of treated water and the smaller the amount of generated sludge. Further, as shown in Table 1 as a result of carrying out with the equipment of FIG. 1, the COD removal rate and the SS removal rate during the experiment period were highest in the cord-shaped carrier.

[0016]

[Table 1]

Also, the amount of sludge generated was small, and there was no concern about clogging. The sludge separated from the carrier is slightly deposited on the lower part, but can be easily removed. If this string-shaped carrier is used, the backwashing system is not necessary because the sludge does not collect, but in order to treat the sludge that is separated from the carrier and slightly accumulates on the bottom, the sludge is dredged under the contact oxidation part. It is preferable to provide a space that can be used. At that time, as a method for dredging and removing sludge, a sludge dredging robot having a real volume for dredging and removing sludge such as a sedimentation pond can be used.
This contact oxidation part is installed inside or on one side of the masonry embankment constructed with split stone. Further, this catalytic oxidation unit can be installed on either the inflow side or the outflow side of the wastewater. Of course, there are not as many contact carriers as masonry embankments,
Microorganisms adhere to it, and under the sunlight, animals and phytoplankton, shellfish, and seaweed adhere, and on top of that, polychaetes and crustaceans also inhabit, forming a wide food chain. It is being removed. Also, this food chain is a much larger food chain than bacteria-protozoa-metazoa as seen in the catalytic oxidation part, and the amount of sludge generated is considerably small.

Further, the masonry embankment is also characterized in that it has a high complementarity with SS. When it is installed on the inflow side, it is used as a pretreatment for removing the coarse suspended matter flowing into the catalytic oxidation part.
Further, when it is installed on the outflow side, it has a function of accelerating the floating sludge separated from the contact carrier of the contact oxidation part.

The amount of oxygen required for the organisms living in these levee bodies can be supplied by the amount of dissolved oxygen dissolved in water, or by breaking waves occurring on the entire levee body. However, when polluted water passes through the bank, much oxygen is used for the respiration of living organisms, and oxygen is insufficient at the contact oxidation part. Therefore, it is necessary to forcibly aerate the catalytic oxidation part and supply oxygen.

As means for forced aeration, there are internal aeration and external aeration outside the levee body, but external aeration is preferable from the viewpoint of maintenance.

For example, if an aerator is hung from the upper part of the dam body to the outer lower part of the dam body so that it can be easily lifted to the upper part, there are few problems in terms of maintenance.

It is also possible to install several levee bodies having the purification equipment of the present invention in series and carry out continuous treatment of several stages. At that time, the sewage flowing into the bank installed in the latter stage is
It is desirable that there is not much gradient of concentration of pollutants or temperature gradient in the vertical direction. Therefore, the device for external aeration is not a normal diffuser type, but a submersible agitating and diffusing device capable of simultaneously performing forced agitation is preferable.

Usually, in the summer sea, the sea surface is warmed,
A thermocline is formed, and the generation of phytoplankton also causes a thermocline in the pollutant concentration. Therefore, the pollutant concentration of the wastewater flowing into the bank is not uniform in the vertical direction, which is not preferable in treating the wastewater. Therefore, when external aeration can be performed at the same time as underwater agitation, the sewage can be made to have a uniform concentration in the vertical direction, and stable treatment can be expected.

When a dam body having the purification equipment of the present invention is installed in a polluted water area, it is possible to create a good flow so that the water in and between the dam bodies or the dam body treated water is not delayed or accumulated. is necessary. At that time, the difference in tidal level and the tidal current
You can also use coastal currents and offshore currents.

Alternatively, it is also an effective means to cause the flow of water in the levee body by drawing out the water on the outlet side of the levee body with a pump or the like.

When the pump is used, it is possible to operate intermittently. That is, the pump may be stopped when the flow naturally forms due to the inflow of rainwater in the winter or when it is raining when the water in the water area is relatively clarified. The only power source of the equipment is the aeration device, which is a factor of power cost. This power cost can be sufficiently reduced by controlling the aeration amount.

For example, ORP (oxidation-reduction potential) or DO (dissolved oxygen concentration) on the side of the catalytic oxidation part or on the side of the bank body
It is also possible to control the aeration amount by measuring and controlling this value. In addition, the upper part of the main bank can be used as a promenade, etc. If it is installed in a water area, it can create a beautiful landscape as a facility in a natural park.

[0028]

The effects of the present invention include the following excellent effects.

First, the purification level and the purification efficiency are improved. Conventionally known permeable levees do not take into account the high concentration of microorganisms that play a central role in removing organic matter, and focus on the formation of a large food chain including higher organisms. It was However, since the levee having the permeation type purification facility of the present invention is provided with the contact oxidation part capable of retaining the microorganisms at a high concentration inside, the microorganisms function well in removing organic substances and the purification level is improved. It is also effective in improving the purification efficiency.

Secondly, it is possible to prevent anaerobicization of sludge accumulated in the embankment having a permeation type purification facility. Conventionally known permeable levees are natural stones or porous artificial stones piled up in the sea, but the prevention of anaerobic sludge generated inside is not particularly considered. However, since the inside of the embankment having the permeation type purification equipment of the present invention is the catalytic oxidation part having a large porosity, the sludge generated therein is not anaerobicized.

Thirdly, the upper part can be utilized as a promenade, etc., and can be fully utilized as a beautiful landscape such as a natural park.
Also, due to the large food chain that can be formed inside the levees with the permeation type purification equipment, the generation of sludge is extremely low.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embankment having a permeation type purification facility having a catalytic oxidation unit inside, which is an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a transparent levee conventionally devised.

[Explanation of symbols]

 1 ... Stone embankment 2 ... Contact carrier 3 ... Contact oxidation part 4 ... Sludge accumulation part 5 ... Underwater agitation diffuser 6 ... Promenade

Claims (8)

[Claims] 1. A catalytic oxidization unit filled with a contact carrier capable of immobilizing microorganisms is provided inside or on one side of a masonry embankment constructed of split stone, etc., and further an aeration device is provided inside or outside. A facility for purifying permeable sewage that has a biological purification function. 2. The equipment according to claim 1 is installed in a polluted water area or in a passage into which polluted water is drawn, and the polluted water is passed through the equipment from one end or both ends,
A method for purifying polluted water, which comprises treating polluted water. 3. The wastewater purification facility according to claim 1, wherein a string-shaped carrier is used as the contact carrier. 4. The wastewater purification facility according to claim 1, wherein a space where the sludge can be dredged and removed is provided at a lower portion of the catalytic oxidation unit. 5. The facility for purifying sewage according to claim 1, wherein a space for human activity such as a boardwalk is provided above the embankment. 6. The sewage purification facility according to claim 1, wherein an underwater agitating and diffusing device is used as a means for external aeration. 7. When the equipment according to claim 1 is installed in a polluted water area, the water on the outlet side of the equipment is intermittently or continuously drawn out by a pump or the like, so that the water flow into the equipment. The method for purifying sewage according to claim 2, characterized in that it is caused. 8. The method for purifying sewage according to claim 2, wherein the amount of aeration is controlled by detecting ORP or DO on the outlet side of the equipment of claim 1 or on the outlet side of the contact aeration unit.