JPH03207493A - Contact material packed deep shaft - Google Patents

Abstract

PURPOSE:To allow an excellent biological treatment and miniaturization by packing contact materials into a riser and decreasing the sectional area ratio of a downcomer with respect to the total sectional area so as to compose a deep shaft. CONSTITUTION:Air is blown from a riser air diffusing pipe 4 of the deep shaft which is decreased in the sectional area ratio of the downcomer 7 with respect to the total area to, for example, 10%. After a circulating flow a is generated by an air lift effect, air for aeration is blown from a down air diffusion pipe 5. Since the contact materials 8 are packed in the riser 6, the excellent biological treatment is possible and the miniaturization of 30% as compared with the conventional deep shaft is possible. The peeling of the biofilms fixed to the contact materials 8 is prevented by decreasing the sectional area ratio of the downcomer 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a contact material-filled Davenyaft in which the riser is filled with a contact material.

[Prior Art] The conventional deep shaft is a type of activated sludge method using floating sludge, and is capable of highly efficient treatment of highly concentrated wastewater. On the other hand, with the contact aeration method that immobilizes microorganisms,
It has the advantage of stable processing performance because various types of microorganisms are attached to it. Therefore, it is thought that by combining the two, it will be possible to achieve excellent biological treatment that combines the high efficiency of the deep shaft with the stability of the contact aeration method.

[Problems to be Solved by the Invention] However, simply filling the riser of a conventional deep shaft with a contact material causes the biofilm immobilized on the contact material to deteriorate due to the high flow velocity in the contact material section. Peeling occurs. On the other hand, when the flow rate is reduced, sediments such as sand and stones are deposited at the bottom of the deep shaft.

Therefore, the present invention provides a contact material-filled deep shaft that reduces the upward flow velocity to an extent that does not cause detachment of the biofilm, and solves the problem of discharge of sediment by intermittent reverse circulation operation of the deep shaft. The purpose is to

[Means for Solving the Problems] In order to achieve the above object, the contact material-filled deep shaft according to the present invention is provided by filling the riser of the deep shaft with a contact material and reducing the cross-sectional area of the downcomer over the entire cross-sectional area. The area ratio is reduced to reduce the upward flow velocity in the contact material portion. In other words, the riser cross-sectional area ratio is increased to reduce the upward flow velocity.

[Function] In deep shaft operation, the descending flow velocity V, in the downcomer needs to be accompanied by air bubbles, so the minimum yD-1. 2 m/sec, and the rising flow rate VR in the riser is set to a minimum VR - 0.0 m/sec due to the necessity of discharging sediment. 7m/se
It is defined as e.

Now, the downcomer cross-sectional area ratio is the general cross-sectional area ratio (1/2
~1/3), for example, by making it 1/10, the rising flow velocity V R -0 - 13 m/se
However, at such a small upward flow rate, the biofilm adhered to the contact material filled in the riser will not be peeled off. Furthermore, by filling the contact material, in addition to the highly efficient processing function of a normal deep shaft, the processing is stabilized by the organisms immobilized on the contact material.

If the ascending flow velocity is reduced as described above, sediment such as sand accumulates at the bottom of the deep shaft and cannot be discharged, but in such a case, the deep shaft is operated intermittently in reverse circulation. Then, the upward flow velocity in the downcomer easily becomes 0.7 m/see or more, and the precipitate ascends the downcomer and is discharged. Note that this reverse circulation operation may be performed for about 2 to 3 hours at night when the load is low.

[Example] Fig. 1 is a block diagram of a deep shaft according to the present invention, and Fig. 2 is a cross-sectional view thereof. In the figure, 1 is an outer cylinder of the deep shaft, 2 is an inner cylinder, 3 is a head tank, 4 is a riser diffuser pipe for generating circulation flow, 5 is a down diffuser pipe for blowing aeration air, 6 is a riser, 7 is a downcomer, and 8 is a contact material filled in the riser 6.

The contact material 8 does not necessarily need to be filled over the entire length of the riser 6, and may be filled only in the upper portion. and,
The ratio of the cross-sectional area of the downcomer 7 to the total cross-sectional area is made small, for example, 10%.

The deep shaft configured as described above is normally operated to treat wastewater. This is similar to the operation of a conventional deep shaft, in which air is blown from the riser diffuser pipe 4, and due to the air lift effect, the circulation flow a shown by the solid arrow in the figure
is generated, and then aeration air is blown in from the down aeration pipe 5. In this case, the descending flow velocity (2) is set to VD-1.2 m/see because it is necessary to entrain air bubbles. Since water circulates through the contact material 8 filled in the riser 6, it has both the functions of a deep shaft and a contact material method. Moreover, since the cross-sectional area SR of the riser 6 is formed larger than that of the conventional one, the rising flow rate VR
is small enough. Assuming that the cross-sectional area ratio of the downcomer 7 is 10% as described above, vR-0.1 is 3 m/see, and therefore, the biofilm adhered to the contact material 8 does not peel off. On the other hand, because the upward flow velocity is so slow, sand and the like accumulate at the bottom of the deep shaft. Therefore, in order to remove such precipitates, reverse circulation b (circulation in the direction of the dashed arrow) is performed intermittently. For this reverse circulation, it is sufficient to stop blowing air from the riser diffuser pipe 4 and blow air only from the down diffuser pipe 5. Since the upward flow velocity in the downcomer 7 easily becomes 0.7 m/see or more, the sediment ascends the downcomer 7 and is discharged. However, in this case, oxygen supply is likely to be insufficient, so reverse circulation operation is performed for about 2 to 3 hours at night when the load is low.

[Effects of the Invention] As described above, according to the present invention, since the riser is filled with contact material, the high efficiency of the conventional deep shaft,
Excellent biological treatment is possible with the combination of stability and stability provided by the contact material. Therefore, it is possible to reduce the size by 30% compared to the conventional deep shaft. Furthermore, by reducing the downcomer cross-sectional area ratio, the biofilm adhered to the contact material does not peel off. In addition, removal of sediment at the bottom of the deep shaft can be handled by intermittent reverse circulation operation.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a deep shaft according to the present invention, and FIG. 2 is a cross-sectional view of FIG. 1. 1...Outer cylinder 2...Inner cylinder 3...Head tank 4...Riser diffuser pipe 5...Down diffuser pipe 6...Riser 7...Downcomer 8...Contact material

Claims (1)

[Claims] In a deep shaft having a downcomer and a riser, the riser is filled with a contact material, and the ratio of the cross-sectional area of the downcomer to the total cross-sectional area is reduced so as to reduce the upward flow velocity in the contact material portion. A deep shaft filled with contact material.