JPS6034886B2 - Wastewater treatment method - Google Patents

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 layer 2.

In this step, air is blown into the sediment to make it easier to sink, and to float, which is then transferred to the next first sedimentation tank 3.
The garbage that floats on the surface of the pond is scraped up and removed by a machine, and the sludge that has settled is scraped from the bottom of the pond and pumped out. The wastewater that has passed through the sedimentation tank 3 is sent to the aeration layer 4, where it is mixed with air and muddy water containing microorganisms.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. Final settling tank 5
The wastewater discharged from the water 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 go through a sludge treatment device 7, such as a thickening tank, a digestion tank, a pseudo 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 treatment process described above, biochemical treatment is carried out in the sedimentation step, which separates water-soluble substances from wastewater in an insoluble form, that is, solids, among pollutants represented by BoD and COD. Coagulation and sedimentation tanks are generally used to separate floc-like solids produced by the action of bacteria from wastewater.

However, since the volume of this sedimentation tank occupies a considerable portion of the wastewater treatment process, it has the disadvantage that it requires a huge amount of land as a treatment facility. The present invention reduces the volume of the flocculation pond to 50% or less by incorporating a furnace filtration device equipped with a moving bed type furnace layer into this wastewater treatment process, thereby reducing the overall height of the wastewater treatment facility. This is an attempt to make the world a better place.

Fig. 2 shows the wastewater treatment method according to the present invention.Those that precipitate are easily settled in the preliminary aeration layer 2 through the sand removal device 1, and those that are floating are made easy to float. The process up to the feeding is completely the same as the conventional example shown in FIG.

First, the overflow from the settling tank 3 is sent to the aeration tank 4, where it is mixed with sewage containing microorganisms and air, and in a state where it is easy to settle, it is subjected to precipitation treatment in the final settling tank 5a. Ru.

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, a lachrymal filtration device 9, which takes up relatively little installation space, is installed next. As a result, the sludge is collected through a filtration system, and the wastewater is then passed through a sterilizer 6 to be purified water. The furnace filtration device 9 uses a combustible furnace material such as pulverized coal, moves lachrymal material by a rotary feeder 10 provided at the bottom of the furnace tank, and is a so-called continuous furnace in which the part through which wastewater passes is always allowed to pass through the furnace. Operable mobile bed disease equipment is used.

As shown in the figure, this filtration device 9 is provided with partition plates at the upper and lower parts of the filtration tank so as to divide the filtration layer into two into the raw water side and the treated water side. A rotary feeder 10 for discharging the furnace material is provided at the lower part of the reactor layer on the treated water side. Therefore, the rotary feeder 10 on the raw water side
By operating at high speed according to the degree of contamination, the reactor overlayer on the raw water side can be moved quickly.

The scope of application of this treatment method is that the quality of the overflow water in the aeration tank is 2000 to 3000 ppm in terms of BoD and COD, and S
When S (solid matter) is around 2000 to 3000 ppm, experiments show that when the volume of the coagulation and sedimentation tank is compressed to the normally required volume i'4, the quality of the overflow water at the outlet of the coagulation and sedimentation tank is BoD. , CODI less than 000ppm, SSIo
o0 ppm or less, and if the water quality is at this level, it is possible to continuously treat it with a moving bed type furnace. Further, if this moving bed type furnace filtration device is installed vertically as necessary, even more sufficient furnace filtration efficiency can be obtained. The capacity of the filtration device is smaller than that of the coagulation and sedimentation tank.

If the volume of the coagulation and sedimentation tank can be halved, even after subtracting the newly added moving bed furnace, the area required for the equipment can be reduced overall, and the investment amount for these wastewater treatment equipment can be reduced. It can be reduced. At the same time, running costs can also be significantly reduced. The moving bed furnace uses combustible materials such as activated carbon, rock plastic, and coal shoulders as its furnace material.

Therefore, it is useful for the effective use of rattan, and the suspended solids in the wastewater that are adsorbed and collected by the furnace material are dried together with the furnace material and finally used effectively as fuel. Since the raw water side reactor layer can be moved quickly, the raw water side sick material and the treated water side reactor material can be used effectively.

In addition, the most suitable particle size of the furnace material should be selected from 0.1 to 1 inch depending on the type of furnace material, waste water quality, discharge standards, etc., but moving bed furnaces Since a filtration device is used, the filtration layer can be adjusted to obtain excellent filtration performance by combining furnace materials with different particle sizes or different types of furnace layers on the raw water side and the treated water side. -Also, since a moving bed type furnace is used, there is no need for a cleaning process for the furnace materials, the processing capacity is greater than that of a fixed bed type furnace, and continuous and stable furnace performance can be obtained. In addition, by reducing the volume of the coagulation sedimentation tank,
Since a moving bed type furnace was used instead, the amount of activated sludge settling in the final settling tank was reduced, and the amount of surplus sludge excluding the amount returned to the aeration tank via piping 8 was extremely small. Therefore, the sludge treatment equipment can also be downsized.

[Brief explanation of drawings]

FIG. 1 shows a conventionally known wastewater treatment device. FIG. 2 shows an example of an apparatus for carrying out the wastewater treatment method according to the present invention. In the figure, 1... Next sand and dust removal device,
2...Preliminary moat tank, 3...First sedimentation tank, 4...
...Aeration tank, 5...Final sedimentation tank, 5a...
... final settling tank (of the present invention), 6 ... sterilization device, 7 ... sludge treatment device, 8 ..., . ．． Piping, 9.
... Furnace filtration device, 10 ... Rotary feeder. Figure 1 Figure 2

Claims (1)

[Claims] 1 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 water-type coagulation sedimentation tank is provided, followed by a filter formed of combustible filter media. Two layered filter beds are installed on the raw water side and the treated water side.
A wastewater treatment method characterized in that the wastewater is separated and filtered using a moving bed type filtration device having a rotary leaf feeder at the bottom of each.