JP3439576B2 - River purification method and purification device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for purifying a river polluted with organic substances, and relates to a new technique capable of purifying river water at a significantly higher speed than ever before.

[0002]

2. Description of the Related Art Domestic sewage (kitchen drain, bath drain, etc.) flows into rivers that run through municipalities where sewers and combined septic tanks have not spread, and is contaminated with organic substances. The pollution level is getting worse with the increase of the population, and there are many cases where rivers are sewage. Such polluted rivers are not only unpleasant, but also adversely affect many living organisms in the river and contaminate drinking water if there is a water supply source downstream.

Therefore, various attempts have been made recently to directly purify rivers, but no definitive technique has been developed yet. A typical conventional technique is the “catalyst contact purification method”. This technology fills a large amount of crushed stone with a large particle size (several centimeters) into a river channel (branching from the main stream of a river) and slowly flows down the river water horizontally for 4 to 5 hours. is there. However, since it takes a long time to clean up, a large amount of crushed stones and a large installation area were required, and it was difficult to apply it except to small rivers with a small amount of water. Moreover, the removal of sludge trapped in the crushed stone filling part was troublesome. Various fillers such as a honeycomb tube and a bundle of fibers bundled in place of crushed stone have been studied, but they have the same drawbacks as the gravel contact oxidation method.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a new technique that can be effectively purified in a polluted river in a significantly shorter time (about 10 minutes) than before, and is also easy to remove sludge.

[0005]

The above-mentioned objects have been achieved by the following inventions. That is, (1) the water in the river or water channel is passed through a packed bed of floating filler having a specific gravity of 0.85 or more and less than 1 which is disposed by being submerged in the water across the river or water channel, and turbidity in the water And / or organic substances are removed, and the amount of water and / or air supplied to the packed bed is increased to wash the packed bed, and the washing wastewater is guided to the outside of the system of the river or water channel to perform solid-liquid separation. After that, the separated liquid is returned to the river or waterway. (2) 1) a first weir that crosses a river or a waterway, and 2) an upstream side of the first weir, which is arranged across the river or a waterway in parallel with the first weir, and has an opening below 3) The second weir and 3) The specific gravity of the sunken and deployed weir is 0.85 or more 1
And less than 4) a packed bed of floating filler and 4) a cleaning drainage pipe provided with opening / closing means opening at the height of the water surface of the second weir and the top end of the packed bed, and 5) arranged outside the system of the river or waterway. 6. A river purification device comprising: a solid-liquid separation device communicating with the washing / drainage pipe; and 6) a pipe for discharging separated water from the solid-liquid separation device to the river or a waterway.

(3) The river purifier according to the above (2), characterized in that an aeration means for introducing air is provided below the packed bed. (4) The river purifier according to the above (2), wherein the second weir has a gate that is openably and closably provided in the lower opening. (5) The river purifier according to the above (4), wherein the gate is divided into a plurality of pieces in the transverse direction and provided so as to be opened and closed individually. (6) The river purification device according to (5), wherein the packed bed is divided into a plurality of parts corresponding to the gates and water is passed only from the corresponding gates. (7) The river purification device according to (2) above, wherein the solid-liquid separation device is a precipitation device. (8) The method for purifying a river according to (1) above, wherein the amount of air blown from the aeration means is increased when the packed bed is washed. (9) When washing the packed bed of the river purification apparatus described in (5) above, some gates are closed and the remaining gates are opened,
The method for purifying a river according to (1) above, wherein the amount of water flow and / or the position of water flow to the packed bed is changed.

In order to carry out the river purification method described in (9) more effectively, it does not prevent the fixed and / or movable structure (baffle, water control, etc.) from being provided below the filling tank. Further, in the case of the purifying apparatus described in (6) above, since the divided filling tanks are treated individually, it goes without saying that the number of wash water distribution pipes installed in the second weir is also required. That is.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the principle of operation of a river purification method and a purification apparatus according to the present invention. Floating particles (plastic granules such as polypropylene and polyethylene, open-cell urethane foam granules, etc.) whose particle size is smaller than that of conventional crushed stones and whose specific surface area is large and whose specific gravity is close to 1 are separated by river walls or river beds through partition walls. It is filled in the water channel provided in, and the river water is allowed to flow upward in the packed bed by a natural flow-down method (no pump is used). A member such as a net is provided above the packed bed to prevent the floating filter medium from flowing out.

Since a large amount of microorganisms are attached to the floating particles having a large specific surface area, the organic matter (BOD) in the river is purified not only by capturing SS but also at a high speed. Because the flow resistance of the floating particle packed bed increases due to the capture of river turbidity and the growth of microorganisms, a large amount of air is intermittently supplied from the bottom of the packed bed 10 times.
The floating particles are disturbed and flowed in for about a minute. As a result, the suspended matter that has been captured by the floating particles is peeled off. The water containing the exfoliated suspended matter is discharged from the cleaning drainage pipe to the outside of the river channel. After a while, the turbid mass of the cleaning drainage decreases, so close the valve of the cleaning drainage pipe to stop the draining of the cleaning drainage.
The washing wastewater flows into the settling tank, and the sludge removed from the filter medium settles. The settling tank is usually installed on the riverside land.

It is important that the specific gravity of the floating solid is 0.85 or more. If the specific gravity is less than this value, the buoyancy is too large, and even if the cleaning air is supplied, the filter medium remains floating and does not flow, so that the floating filter medium cannot be washed. The particle size of the floating particles is preferably 10 mm or less (preferably 2 to 4 mm) to increase the specific surface area and increase the amount of adhering microorganisms. The upward flow velocity in the packed bed of the river can be set to a considerably high flow velocity of about 100 to 150 m / d. The height of the floating packed bed is not more than the depth of the river and is usually about 1 to 2 m. Therefore, the residence time of the packed bed is about 10 minutes, and purification can be performed in a significantly shorter time than in the past. The amount of air diffused for microbial respiration is BO
D inflow load (kg / d), aeration oxygen absorption efficiency (8%
Degree) to determine. The BOD of the river is 10
When the amount is less than mg / l, it can be purified by the dissolved oxygen in the river itself, and aeration for microbial respiration is not always necessary.

The air supply amount for cleaning the filter medium is such that the linear air velocity of the packed bed is 1 m / min or more. With this air linear velocity, the floating filter medium flows sufficiently and effective filter medium cleaning can be performed. The partition wall of the floating packed bed, that is, the weir is preferably made of a concrete with a large weight so as not to be washed away by the water flow in a normal river, but the underwater structure of the present invention is formed as an integral type or a split type unit, It may be installed in a small waterway. If the floating filter medium packed bed is divided into a plurality of units and the filter medium cleaning is performed at different times for each unit, the cleaning drainage amount can be reduced. In this way, the amount of cleaning waste water is stabilized, and interruption of the purification process is avoided as much as possible.
When cleaning, if the gate operation is properly performed, the pressure of the river water itself can be used without power. As a sedimentation tank for cleaning wastewater treatment, a tank filled with a filter medium having a large porosity (for example, a hollow cylindrical filter medium) is preferable to a simple sedimentation tank because the sedimentation effect is excellent.

[0012]

EXAMPLES The effects of the present invention will be described in more detail below with reference to examples.

Example Simulating a polluted river, activated polluted treated water (BOD)
The test of the present invention was carried out for 10 to 15 mg / l and SS8 to 11 mg / l) as shown in FIG. The test conditions are shown below. Floating filter type: Polyethylene granular material Floating filter particle size: 2-3 mm Floating filter specific gravity: 0.95 Filter medium filling height: 1.5 m Raw water flow rate: 2 l / min Raw water upward velocity: 200 m / d Filter washing air Flow rate: 1.5 m / min Packed bed retention time: 10.8 min Filter media cleaning frequency: Once a day Filter media cleaning time: 20 min As a result of conducting a one-year water flow test under the above conditions, treatment was carried out throughout the year Water BOD3-5 mg / l, treated water SS1.2-
It was 2.6 mg / l, and good treated water was obtained, thus demonstrating the effect of the present invention on a polluted river. The filter medium washing wastewater was supplied at a horizontal flow velocity of 50 m / d to a contact cross-flow sedimentation tank filled with a polypropylene hollow cylindrical filter material having a particle diameter of 25 mm, and the sedimentation tank outflow water quality was BOD 4-5 mg / l, SS.
The amount was 2.5 to 3.2 mg / l, which was sufficiently purified.

[0014]

According to the present invention, since the packed bed can be easily washed, SS and BOD in river water can be treated efficiently and continuously, and the unitization makes it easy to install the purification device. Becomes

[Brief description of drawings]

FIG. 1 is a diagram showing the principle of operation of a river purification method and a purification apparatus according to the present invention.

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Claims (5)

(57) [Claims] 1. Water suspended in a river or waterway is passed through a packed bed of a floating filler having a specific gravity of 0.85 or more and less than 1 which is disposed by being submerged in the water across the river or waterway, and the suspended matter in the water is passed through. And / or organic substances are removed, and the amount of water and / or air supplied to the packed bed is increased to wash the packed bed, and the washing wastewater is guided to the outside of the system of the river or water channel to perform solid-liquid separation. After that, the separated liquid is returned to the river or waterway. 2. A first weir that crosses a river or a waterway. 2) An upstream side of the first weir is arranged transversely to the river or waterway parallel to the first weir, and an opening is formed below. The second weir provided, 3) The specific gravity of the submerged and deployed weir is 0.8.
5 or more but less than 1 packed bed of floating filler, 4) Washing water distribution pipe equipped with opening / closing means opening at the height of the water surface of the second weir and the top of the packed bed, 5) Outside the system of the river or waterway And a pipe for discharging the separated water from the solid-liquid separation device to the river or the waterway, and a purification device for a river. 3. The second weir has a gate that is openably and closably provided in a lower opening portion, and the gate is divided into a plurality of parts in a transverse direction and individually opened and closably provided. The river purification device according to claim 2. 4. The second weir has a gate openably and closably provided in a lower opening, and the filling layer is divided into a plurality of portions corresponding to the gate, and water is passed only from the corresponding gate. The river purification device according to claim 3, wherein 5. When cleaning the packed bed of the river purification apparatus according to claim 3, some of the gates are closed and the remaining gates are opened to change the water flow amount and / or the water flow position to the packed bed. The method for purifying a river according to claim 1, characterized in that.