JPS58166914A - Treatment of waste water - Google Patents

Abstract

PURPOSE:To decrease the volume of a flocculating and settling basin and to reduce the size of waste water treatment facilities by incorporating a filter device provided with a moving bed type filter machine in waste water treatment stages. CONSTITUTION:Waste water is supplied through a dust removing device 1 using grit into a preliminary aeration tank 2, where the materials that settle are made easier to settle and the materials that suspend are made easier to suspend. The aerated water is fed into a settling basin 3. The overflow liquid from the basin 3 is fed to an aeration tank 4, where the sludge contg. microorganisms and air are mixed therewith under stirring and the water in the state vulnerable to settling is subjected to settling in a final settling basin 5a. The size of the basin 5a is made smaller by about 50% as compared to the prior art. A filter device 9 requiring relatively small installation volume is placed, and the sludge is filtered and recovered with said device, whereafter the waste water is sterilized with a sterilizer 6 to clean water. A moving bed type filter machine which uses combustible filter media such as pulverized coal and in which the filter media are moved by the lower part of the filter tank is used for the device 9.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wastewater treatment method for purifying industrial wastewater, sewage, human waste, and the like.

In conventional wastewater treatment, as shown in FIG. 1, first, sand, dust, etc. are removed by a sand settling and dust removal device 1, and then the wastewater is sent to a preliminary aeration tank 2. Air is blown in and agitated to make things that sink easier to sink and things that float easier to float, and then sent to the first sedimentation tank 3, where debris floating on the water surface is scraped up and removed by a machine. The settled sludge is scraped up at the bottom of the pond and pumped out.

The wastewater that has passed through the sedimentation tank 3 is sent to the aeration tank 4, where it is mixed with muddy water containing microorganisms and air and stirred.The microorganisms feed on the organic matter in the sewage, take dissolved oxygen from the water, multiply, and settle. and is precipitated in the final settling tank 5. The wastewater discharged from the final settling tank 5 is sterilized from bacteria such as E. coli in a sterilizer 6, and is then reused as purified water or discharged into the river.

On the other hand, the sludge settled in the first settling tank and the activated sludge settled in the final settling tank are sent to a sludge treatment device, such as a thickening tank, a digestion tank, a flocculating tank, a dryer, etc., and are then landfilled or incinerated. A part of the activated sludge is returned to the aeration tank 4 via the pipe 8, and only the surplus is sent to the sludge treatment device 7.

Now, in the processing process as shown above, BoD, CoD
In the sedimentation process, which separates substances from insoluble forms, i.e., solids, from the wastewater, a coagulation sedimentation tank is generally used to apply biochemical treatment and separate floc-like solids generated by the action of bacteria from the wastewater. It is being However, since the volume of this sedimentation tank is the main part of the wastewater treatment process,
Huge amount of land for processing equipment? There was an inconvenience.

The present invention incorporates a filtration device equipped with a moving bed type p-filter into this wastewater treatment process, thereby reducing the capacity of the coagulation sedimentation tank to 50% or less, thereby reducing the overall size of wastewater treatment facilities. It's what I'm trying to figure out.

Fig. 2 shows the wastewater treatment method according to the present invention, in which the wastewater that enters the preliminary aeration tank 2 via the sand settling and dust removal device 1 is easily settled, and the floating waste is made easy to float and is first transferred to the settling tank 3. The process up to the feeding is completely the same as the conventional example shown in FIG.

First, the overflow from the sedimentation tank 3 is sent to the aeration tank 4, where it is mixed with muddy water containing microorganisms and air, stirred, and in a state where it becomes easier to settle, it is subjected to sedimentation treatment in the final sedimentation tank 5a. .

The size of this final settling tank 5a is reduced by about 50% compared to the first case. It is natural that the sludge recovery rate in the wastewater in this sedimentation tank decreases as the sediment decreases, but in the present invention, next to this is a filtration device 9 that takes up a relatively small installation volume. As a result, the sludge is filtered and recovered, and then the waste water is passed through the sterilizer 6 to be purified water.

The filtration device 9 uses combustible furnace material such as pulverized coal, moves the filtration material by a rotary feeder 10, etc. provided at the bottom of the filtration tank, and is capable of so-called continuous operation in which the portion through which wastewater passes can always be filtered. A moving bed filtration machine is used.

The scope of application of this treatment method is that the quality of the overflow water from the aeration tank is BoD, -CoD, 2,000 to 3,000p.
pm, 2,000-3,000 p at 88 (solid material)
pm, experiments have shown that when the volume of the coagulation and sedimentation tank is compressed to 1/4 of the normally required volume, the quality of the overflow water at the outlet of the coagulation and sedimentation tank is BoD, CoD 1,000.
ppm or less, SS l, 000 ppm or less,
If the water quality is at this level, it is possible to treat it continuously using a moving bed type filtration device. Further, by vertically installing this movable bed-type off-shore passing device as necessary, a more sufficient p-overmovement rate can be obtained.

The volume of the filtration device is much smaller than that of the coagulation sedimentation tank. If the volume of the coagulation and sedimentation basin can be halved, even after subtracting the newly added moving bed filtration equipment, the area required for the equipment can be reduced overall, reducing the investment amount for these wastewater treatment equipment. can. At the same time, running costs can also be significantly reduced.

The movable bed type filtration equipment uses combustible materials such as activated carbon, mausoleum plastic, limestone layer, etc. Therefore, it is useful for the effective use of waste materials, and the suspended solids in the wastewater that are adsorbed and collected by this material are dried together with the P material and finally used effectively as fuel.

The particle size of the furnace material should be 0.1-io++ ms depending on the type of furnace material, waste water quality, discharge standards, etc., and the most appropriate one should be selected and used. Therefore, it is possible to adjust the p-filtration layer to obtain excellent filtration performance by combining furnace materials with different particle sizes or different types of p-materials on the raw water side and the treated water side. Furthermore, since a moving bed type filtering device is used, there is no need for a cleaning process for the furnace material, the processing capacity is greater than that of a fixed bed type filtering device, and continuous and stable filtration performance can be obtained.

Furthermore, by reducing the volume of the coagulation sedimentation tank and replacing it with a moving bed type filtration device, the amount of activated sludge that settles in the final sedimentation tank is reduced, and the amount returned to the aeration tank via 8 tons of piping is reduced. Since the amount of excess sludge removed is extremely small, the sludge treatment equipment can also be downsized.

[Brief explanation of the drawing]

FIG. 1 shows a conventionally known wastewater treatment device. FIG. 2 shows an example of a device for carrying out the wastewater treatment method according to the present invention. In the figure, 1 sand and dust removal device 2 preliminary aeration tank 3 first settling tank 4 aeration tank 5 final settling tank 5a (of the present invention) final settling tank 6 sterilization device I sludge treatment device 8 piping
9 Filtration device 10 Rotary feeder or above

Claims (1)

[Claims] In a method of solid-liquid separation of pollutants present in treated water after physical treatment and biochemical treatment using a coagulation sedimentation tank, a small coagulation sedimentation tank is installed, followed by a combustible filter. A wastewater treatment method characterized in that filtration is carried out using a moving bed type filtration device having a layered filtration bed.