JPS5935679B2 - Advanced treatment method for organic wastewater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an advanced treatment method for organic wastewater such as urban sewage and industrial wastewater.

Currently, for the treatment of organic wastewater such as urban sewage and industrial wastewater,
High-grade treatment using biological treatment methods, mainly activated sludge methods, is widely practiced.

B due to this high-grade treatment, 0. D removal rate is 90-95%.

That is, the removal limit for B, O, and D is 15 to 20 ppm.

On the other hand, the minimum standard for river living environment (Type E) is B.
,0. D 10ppm or less is required.

Furthermore, when river water is used as raw water for water supply (class 3), the secondary treated sewage water discharged into the river is B, 0.
．． D 3ppm or less is now required.

However, the current high-grade secondary treated water is 8.0. Since D is 15 to 20 ppm as described above, environmental standards cannot be achieved depending on the amount of water discharged into the river.

Therefore, in order to achieve environmental standards and prevent eutrophication through advanced treatment of organic wastewater, so-called tertiary treatment is required.

This tertiary processing consists of B, 0. In addition to D and SS, the main targets are nitrogen salts, phosphates, and detergents (A, B, and S).

Tertiary treatments include coagulation, precipitation, filtration, and adsorption with activated carbon, but these methods are not practical from an economical point of view unless they are reused as industrial water.

The present invention has been made in view of these points, and the water to be treated is gravity-filtered using a gravity-type filtration device, and a part of the filtrate water is circulated and aerated with an aeration device. Dissolved oxygen is supplied to the treated water, the surface of the r-vortex layer is stirred, and foam is separated, and the chemical is directly injected into the aeration section to cause a flocculation reaction.

That is, the present invention provides B in secondary treatment water, 0. D.
In addition to SS, NH3-N, phosphates and detergents (A, B,
By using biological methods as the main method and accompanying physical and chemical methods to remove S), the retention effect and biological oxidation effect, which are the outstanding characteristics of the slow stream vortex shape, using a gravity type filtration device can be achieved. By making use of the 1, which results in B.
O6D 3ppm or less, SSlppm or less, NH3-
No, 5 ppm or less, phosphate pQ,' 1-5
ppm or less, and detergent (A, B, S) 1.5
It provides something that can perform advanced processing of less than ppm.

An embodiment of the present invention will be described with reference to the drawings.

Reference numeral 1 denotes a storage tank for raw water, and an aeration tank 4 is connected to this storage tank 1 via a channel 3 having a pump 2. A sedimentation tank 5 is connected to this aeration tank 4.
A storage tank 7 for secondary treated water is connected to the sedimentation tank 5 via a channel 6.

A filtration device 10 is connected to this storage tank 7 via a channel 9 having a pump 8.

This filtration device 10 is composed of a first filtration tank 11 and a second filtration tank 12, and these 10th filtration tank 11
In the lower part of the second swamp tank 12, there are swamp vortex layers 13 and 14 formed of swamp material made of crushed stone of coarse grain size or crushed stone of artificial lightweight aggregate mesalite, and these swamp vortex layers 13, 1
A filter basin 15° 16 is formed above the filter 4.

In this case, the diameter of the crushed stones of the filtration material in the first filtration layer 13 of the first filtration tank 11 is made larger than the diameter of the crushed stones of the filtration material in the vortex layer 14 of the second filtration tank 12.

Furthermore, aeration devices 17 and 1B are provided in the filter basins 15 and 16 of the filtration tank LL12.

These aeration devices 17 and 18 are provided with gas diffusers 19 and 2 made of a diffuser tube or the like above the stream vortex layers 13 and 14.
A blower 22 is connected to these gas diffusers 19 and 20 via an air pipe 21.

Further, circulation devices 23 and 24 are provided in the overflow tanks 11 and 12.

These circulation devices 23, 24 have a flow path 27 with a pump 25, 26 between the lower and upper parts of the filtration tanks 11, 12,
28 to form a connection.

Further, lids 29, 30 are provided on the tops of the overflow tanks 11 and 12, and a foam separating and removing device 3L32 consisting of a trough is provided at the top of these lids 29, 30, and these foam separating and removing devices 31. 32 through a flow path 33 to a foam storage tank 34
Connect.

Further, a drug injection device 3 is provided above the tenth overflow tank 11.
6 will be provided.

This drug injection device 36 connects a supply pipe 39 having a pump 38 from a drug reservoir 37 to the upper part of the first overflow tank 11 .

Then, the flow path 9 from the storage tank γ is connected to the upper part of the tenth overflow tank 11, and the flow path 40 is connected between the lower part of the first overflow tank 11 and the upper part of the second overflow tank 12. Furthermore, a storage tank 42 for tertiary treated water is connected from the lower part of the second sewage tank 12 via a flow path 41, and a flow path 43 for discharge is connected to this storage tank 42.

Note that the lower parts of the overflow tanks 11 and 12 are connected to the storage tank 42 through a flow path 45 having a pump 44, and furthermore, water collection troughs 46 and 47 are provided at the upper parts of the overflow tanks 11 and 12. A cleaning water storage tank 49 is connected to the water collection troughs 46 and 47 of this through a flow path 48, and this storage tank 49 is connected to a pump 50.
The aeration tank 4 is connected to the aeration tank 4 through a flow path 51 having a flow path 51 .

In such an apparatus, raw water is guided from a storage tank 1 by a pump 2 to an aeration tank 4 via a flow path 3, where it is oxidized, and also subjected to a sedimentation treatment in a sedimentation tank 5 for secondary treatment.

Then, this secondary treated water is guided to a storage tank 7 via a flow path 6.

Next, the secondary treated water flows into the first filtration tank 11 of the filtration device 10 from the upper part through the flow path 9 by the pump 8, flows out from the lower part through the swamp vortex layer 13, and further flows into the flow path 40.
It flows from the upper part of the second swamp tank 12 through the swamp vortex layer 1.
Let it flow out from the bottom through 4.

At this time, an aeration device 17.18 is used for the inflow water.
The air pipe 21 is connected by the blower 22 from the air diffusers 19 and 20.
Aeration is performed by the air supplied through the vortex layer 13, 14, which supplies dissolved oxygen to the secondary treated water and circulating filtrate water, aggregation reaction of the injected drug, and vortex layers 13, 14.
Performs surface stirring and foaming actions.

When this secondary treated water sufficiently contains dissolved oxygen, it passes through the stream vortex layers 13 and 14, activated sludge particles retained throughout the stream vortex layers 13 and 14, and the stream vortex layer 13
．． Oxygen is supplied to the biofilm formed in the 14 chamber, which is made up of aerobic microorganisms, and purification is carried out by making the most effective use of the oxidation, adsorption, and purification effects of the aerobic microorganisms.

In addition, the filtered water is circulated from the lower part of the filtration tanks 11 and 12 to the circulation device 2.
3,240 pumps 25, 26 flow into the filtration basins 15, 160 aeration section through the flow channels 2γ, 28 and perform high-speed circulation contact filtration of the filtration layers 13, 14.
A decrease in dissolved oxygen in the stream vortex layers 13 and 14 is prevented, and a high concentration of dissolved oxygen is maintained.

In addition, detergent (A,
B, S), and other foamable substances are foamed, and the foamed liquid is collected by the lids 29 and 30 of the filtration tanks 11 and 12, and a foam separation and removal device consisting of a trough provided at the top is formed. 31 and 32 are led to a storage tank 34 via a flow path 33.

Then, the pump 38 is pumped from the drug tank 37 of the drug injection device 36.
A drug such as sulfuric acid is first supplied through the supply pipe 39.
It is directly injected into the aeration section of the filtration pond 15 of the filtration tank 11 to remove phosphates (PO4'-) and other substances that can be removed with chemicals.

In this way, the pretreated secondary treated water is filtered through the stream swirl layers 13 and 14 of the tenth stream filter tank 11 and the second stream filter tank 12, and is subjected to tertiary treatment.

Then, this tertiary treated water is passed through a flow path 41 to a storage tank 42.
guided by.

Then, the tertiary treated water is discharged through the flow path 43.

In addition, when cleaning the p-vortex layers 13 and 140, the tertiary treated water is pumped from the storage tank 42 through the flow path 45 to the filtration tank 1L.
12, the cleaning wastewater flows back to the upper trough 46,
47 and guided to a storage tank 49 via a flow path 48,
The water is returned to the aeration tank 4 from the pump 50 via the channel 51.

Note that the artificial lightweight aggregate Mesalite is excellent as a filter material that forms the stream vortex layer in the stream filter tank.

This material is made from shale calcined at 1000 degrees Celsius, and because it contains stone with many pores, it is hard and light.
Moreover, it is an artificial lightweight aggregate that has low water absorption and is chemically stable.

For example, this is crushed and finely granulated and used as a filter material of the first stream swirl layer with an average diameter of LOmm±2, and as a filter material of the second stream swirl layer with an average diameter of LOmm±2.

Therefore, it is lightweight (specific gravity 1.7), heat-resistant, easy to clean, and requires only a small amount of potash cleaning water.

In addition, because it is porous, it easily adsorbs and captures activated sludge particles and other fine suspended substances, and has high strength, so there is less damage due to wear and tear, and it can be used semi-permanently, and is inexpensive and economical. be.

In addition, since deep sewage is performed using sewage material with coarse particle size, the increase in head loss is extremely small, and therefore sewage continues for a long time (except for backwashing for 5 minutes once a week). No driving operation required.

Next, an experimental example of the present invention will be shown.

For the experiment, a filtration device with the structure shown in the figure was used, and the filtration tank had a height of 200 cm, an inner diameter of 4 cr, and a cross-sectional area of 12.56 cm.
The cylindrical shape of CrA is formed, and the sawa vortex layer is made by crushing and finely granulating the artificial lightweight aggregate mesalite, and the first tank has an average diameter of 10 m7IL.
±2, and the average diameter in the second tank! A vortex layer consisting of a 5mm±2 sieve material was formed to have a thickness of 100α.

In addition, p filtration speed 50m/D, filtration pond aeration 20
0 m/D, and the circulation rate of the sewage water was 300 m/D.The sample raw water used was secondary treated water obtained by treating organic sewage from urban sewage and synthetic sewage using the activated sludge method. there was.

Experimental Example 1 (Addition of 1100 pp of sulfuric acid band) Experimental Example 2 The effects of r-filter aeration and r-peroxide circulation on the removal of NH3-N were examined.

In each experiment, the residence time of the stream vortex layer through the first tank and the second tank was 3 hours.

Experiment/l'6'll Filter pond without aeration.

Experiment/162; Perform f' over-pond aeration and drain thoroughly.

Experiment 43; 2p filter aeration and swamp water are circulated and swamped.

According to this Experimental Example 1, the illegally treated water is of extremely high quality, with B.0. D 3ppm or less, NH3-No
, 5 ppm or less, plus detergents (A, B, S)
Under 1.5 ppm Jl, phosphoric acid PO4' 1.5 pp
It was confirmed that high-quality treated water of less than m.

In addition, in the removal of ONH3-N in Experimental Example 2, when the retention time in the stream vortex layer was kept constant at 3 hours in each experiment, if the filter basin aeration in Experiment 1 was not performed and the stream was filtered,
The removal of NH3-N was 41.1% when 15.5% Tearly was used and the Sawagaike aeration of Experiment 42 was carried out, and the removal of NH3-N was 41.1%. It was confirmed that the method of aeration and circulating and r-filtering water promotes a high degree of nitrification, with 98.8% of NH3-H being removed.

According to the present invention, by aerating the water to be treated in the filtration pond above the gravity type filtration device, detergents (A, B,
Combined with foam separation, soluble non-biodegradable substances such as S) can be discharged outside the tank, making it possible to remove 90% or more.

In addition, by aerating the water to be treated in the sewage basin above the gravity sewage tank, sufficient dissolved oxygen is supplied, which allows aerobic microorganisms to grow in the presence of dissolved oxygen. Biological oxidation and assimilation of organic foam water by aerobic microorganisms is also performed, and B, O, and D can be removed.

Moreover, the aeration above Sawagaru Pond agitates the liquid level above the Sawa vortex layer, prevents suspended solids from accumulating in the upper part of the Sawa vortex layer, and makes it easier for suspended solids to enter the lower part of the Sawa vortex layer.
Therefore, it is possible to effectively utilize the entire filtration layer, and it is also possible to significantly extend the swell duration time.

In addition, NH3-N is stabilized by being oxidized sequentially from N02-N to N03-N, and the rate of this oxidation is largely determined by temperature, dissolved oxygen, and contact time. For example, stoichiometrically, 1 kg of NH3-N Oxidation requires 4.6 kg of oxygen, and if the dissolved oxygen in the swamp layer falls below 1 ppm, the process will not proceed, but the deoxidized water is pumped or airlifted to the aeration section of the swamp pond and then to the swamp vortex layer. By passing through high-speed circulation contact with B, the biological bodies in the r vortex layer are supplied with oxygen and the number of contacts is increased.
0. D. In addition to removing SS, nitrification is promoted, and N
It can remove H3-N and exhibits advanced purification function.

Furthermore, by directly injecting a specified chemical into the aeration section of the water to be treated, for example, phosphates can be reliably removed using aluminum sulfate or other agents that make phosphoric acid insoluble. Remove against.

By injecting chemicals according to the substance, the water to be treated can be aerated and the specified substances can be reliably removed.It can also be used for both purposes without the need for a separate sedimentation device just for this purpose, allowing efficient treatment of organic sewage. is possible.

Therefore, B, O, D, SS, NH in organic wastewater
3-N, phosphoric acid, detergents, etc. can be effectively purified and removed by only a single filtration operation, such as B, 0.
D 3ppm or less, SSlppm or less, NH3-NO
, 5 ppm or less, phosphoric acid POj 1.5 ppm or less,
In addition, it is possible to obtain extremely highly stable treated water with detergents (A, B, S) of 1.5 ppm or less and potassium stability.

[Brief explanation of the drawing]

The figure is a process diagram showing an embodiment of the present invention. 10...Gravity flow device, 11,12...Song 1
Supertank, 13, 14...Sawa vortex layer, 15, 16...
Karasawa Toike, 17, 18...Air lag device, 23゜24...Circulation device, 29,30...
... Lid body, 31°32 ... Foam separator, 3
6... Drug injection device.

Claims (1)

[Claims] 1. The water to be treated is subjected to gravity filtration in a gravity filtration device equipped with a vortex layer, and the water to be treated is aerated in a filtration pond above the r vortex layer, and the water is filtrated in the filtration device described above. In addition to circulating a part of the water, the foam generated from the water to be treated is separated and removed in the upper part of the filtration device, and furthermore, certain substances are removed from the water to be treated in the filtration pond of the vortex layer. An advanced treatment method for organic sewage characterized by injecting a chemical that