JPS607995A - Aeration tank in filthy water treating process using activated sludge - Google Patents

Abstract

PURPOSE:To secure aggregation of microorganism in an aeration tank and to stabilize purifying function by arranging proportion of the amt. of introduced org. material to the amt. of microorganism in the tank to freely adjustable condition and enabling charge and discharge of aeration unit to the tank smoothly performable and holding contact materials always at below the water level in the tank. CONSTITUTION:An aeration tank 2 having a manhole 12 with a lid at the top and an air-dispersing device 1 in the inside is communicated to a settling tank 9 through a communicating pipe 13. The water levels of the both tanks 2, 9 are regulated to be same level by an overflow trough 14 provided in the settling tank 9. The tank is constituted so as to enable charge and discharge of units 3 through the manhole 12 freely and to hold contact materials 3a at below the level of the treated water WL in the tank 2. By increasing or decreasing the number of the unit 3 to be charged to the tank 2, the proportion of the amt. of org. material to be introduced to the amt. of microorganism is adjustable optionally.

Description

[Detailed Description of the Invention] Kippatsu 81-] is used in the aeration tank used in the activated sludge type sewage treatment method, which is most often adopted in industrial wastewater treatment and domestic wastewater treatment.

In recent years, closed water bodies such as small rivers, lakes, and inner bays have become eutrophic due to the influx of organic substances and nutrients, causing various damage to fisheries and water supplies.

Domestic wastewater has a high contribution rate to the inflow load of these organic matter and nutrients, and of this, malicious discharge water due to insufficient maintenance of small human waste septic tanks accounts for a particularly large proportion.

Although the activated sludge method described above has excellent purification ability and is said to be maintenance-dependent, in order to stabilize its function, it is necessary to It is necessary to properly manage the solid-liquid content and the amount of returned sludge, but in reality, it is difficult to have a dedicated manager on site, especially for small-scale sludge, and the sludge has been left unattended for a long time. There are many cases where this happens. Therefore, there is a large disparity between the maximum and minimum sewage inflow load, especially in tourist areas such as inns, resorts, stadiums, amusement parks, and various gathering places. may occur, and the treated water may be discharged as residue without satisfying discharge 41 to quasi-value.

Unfortunately, in the case of combined purification treatment of gray water and collected urine, the amount of inflow, quality of inflow water, structure of the treatment facility, etc. are uniquely determined by the Architectural Certification Law, and in many cases they do not match the actual situation. . For example, if the influent BOD concentration is -200
mg/l, if, water input SS degree is 2jOmg/
In the case where h is defined as l, the inflow water BOD y3 degrees with 'U<fi''A is /θO~/j0mg/l.

There are cases where the SS concentration in the inflow water is /jθ~2θθmg/l, and the inflow amount is also determined by a more controversial topic than the actual one.
As a result, the actual inflow BOD load (CBOD concentration x inflow concentration) is usually about ⅓ to η of the design value.

The same applies to water in factories, where it is possible to reduce production volume, the number of workers, or minimize the amount of water used in the production process.

As described above, when the inflow BOD load decreases beyond a certain level compared to the design end, that is, when the processing equipment volume b1 such as the aeration tank increases above a certain level relative to the inflow BOD load,
The following problems occur when the load (i.e., inflow BOL) decreases below the metering range:
Biological treatment cannot be handled under the same operating conditions,
Activated sludge floc! The purifying function of these bodies is significantly reduced due to outflow and a decrease in activity. Especially for a long time! ! ] In the aeration type aerated sludge method, when the organic matter inflow Lk decreases to less than half, the F/R1 ratio (4 inflowing substances/microorganisms involved in purification) falls below the allowable range of 8, and the microbial population in the tank decreases. It is no longer possible to maintain this, and the MLSS concentration (an index representing biomass) gradually decreases to 9. the result,
The purification capacity deteriorates to the extent that the treated water exceeds the discharge standard value, and as long as the inflow conditions remain the same, this condition will not recover naturally and will continue to worsen.

Possible countermeasures against the reduction in purification ability due to such a reduction in inflow BOD load include the following. This will be explained with reference to the schematic configuration of the processing flow shown in FIG.

1 = (), P, m adjustment 4 + 1i Transfer the water from 41 to the air tank (6) via the pump (6) to reduce the amount of raw water inflow, that is, the inflow BOL) load. Accordingly, reduce the number of Zhao's burdens to avoid being attacked by Xiaojie.

(b) Reduce the air supply to the 14% air tank (5) via the air diffuser +11 consisting of the blower (7) and the air diffuser pipe (8) to reduce dissolved oxygen in the air (5). +i'rl I(
jJ.

(c) Reduce the amount of sludge returned from the sedimentation tank (9) to the air flow tank (5), increase the residence time in the sedimentation tank (9) to improve the solid-liquid content, and improve activated sludge Prevent spills.

2) Pour the highly active seed sludge from the Karasou Riba into the aeration tank (5) 1.

i; I-, 1jjl The microorganism population in the tank is fixed and maintained in the tank.

In Figure 1, ^('tt) is the final processing,
1) Upper tank.

”Among the countermeasures mentioned above, are a) to (c) simple modifications to the equipment? -1 (Although it can be dealt with, it cannot be taken as a drastic measure considering the inadequate and inappropriate maintenance as mentioned above, or), because it is simply adding seed sludge. Even if it is effective in the short term, it will suddenly return to its original state after a certain period of time, so this alone will not be a viable countermeasure like (a) to (c).

The government believes that these are the best countermeasures from a long-term perspective. It is possible to remodel the building, but in the former case, water must be drained from the aeration facility during the remodeling period, and sewage treatment cannot be performed during that period.Also, if the tank is made of synthetic resin such as FRP, it may be necessary to fix the contact material. However, in the latter case, there are problems with the installation space of the 1-disk drive device and the problem of the empty space above the water surface.
There are many cases where modification is difficult or impossible due to the problem of insufficient il height, etc., and it is also possible to add a contact aeration tank or rotating contact tank next to the settling tank as a countermeasure similar to mountain →. However, in this case, it is economically disadvantageous compared to remodeling the aeration tank itself, since the construction cost is high and the energy input to the existing aeration tank is wasted.

In view of the above circumstances, it is an object of the present invention to make it possible to easily implement the above-mentioned countermeasures Cj-, l while deepening the continuous treatment state by modifying the existing aeration tank itself.

Kibatsu L was developed to achieve the above purpose! Characteristics of the aeration tank in the activated sludge sewage treatment method related to IJ, t? ,7
The structure is configured such that the contact material is held below the water surface when the tank with the air diffuser installed can be freely moved in and out of the tank (organic matter inflow amount/Ken Seishosha). The present invention is configured to be adjustable by increasing or decreasing the number of input units, and the effects of the present invention having such a characteristic configuration are as follows.

If the inflow BOD load fluctuates for any reason or is expected to increase, the number of inputs of the unit may be increased or decreased while maintaining the aeration operation or even the operation status of the entire treatment facility. Not only can an existing aeration tank itself be easily converted into a contact aeration tank with a simple work, but also the contact area and material of the unit can be arbitrarily and easily changed as necessary. can do. Therefore, inflow BOD
The variation in purification function due to load fluctuation is o'j4
This can be suppressed as much as possible by simple and economical means such as moving the unit in and out of the air tank itself, ensuring the microbial population in the tank and stabilizing the purification function regardless of fluctuations in the inflow BOD load. With Tsubu.

Examples of the present invention will be described in detail below based on the drawings.

One mixed air tank (5) in the activated sludge sewage treatment method shown in Figure 1, which shows the overall treatment flow, is generally constructed as follows.

r (As shown in Fig. 52 and Fig. 3, a tank (2) with a lid opening manhole 1I21 at the top and an air diffuser 1 or fi+ inside is connected to a sedimentation tank (9) via a communication pipe 031. ), and +14!/M provided in this sedimentation tank (9) as well)
The water level in both tanks (21, (9) is regulated to the same level by rough (141).
In Figure J2, (3) is 4 through the entire length of the manhole.
'+1 (A unit that is suddenly constructed in such a way that it can be put in and taken out freely in 21, and in the put state, the contact material (3a) can be held below the treated water surface (WL) of tank (2) l11,
As shown in Figures 4 and 5, this is a plastic support frame (3A) that is constructed of a rectangular or cylindrical shape that can be disassembled by combining a plurality of strips, and a floating bag (3B) is attached to the top of the plastic support frame (3A).
A contact material (3a) made of reticulated cylindrical polyethylene and having a specific surface area of 30 to 10 θm"7m and a specific gravity of 03 to 0.0m" is fixedly held at the bottom of the support frame (3A), and its Ir
A void (3C) is formed in the contact material (3a) so that the sewage flows evenly in contact with the contact material (3a), and the Fm of the support frame (3A) is
In addition, the ratio Ji is adjusted by 1 of the number of pieces collected in the attack.
J) is attached. A unit like this (
3) The 17M ratio in Sodium Sodium (2) can be adjusted by increasing or decreasing the number of injected into the tank (2).

In addition, the unit (3) introduced in 4t'H21 is 4j
If the position is fixed inside the '1i21, maintenance is easy, but even if the position is not fixed and it is simply floated, the 1st offensive air unit is activated by one swirling flow of the treated water accompanying the ventilation from (1). Position iii of (3) is immobile in the pose and position shown in FIG.

Next, a previous example conducted by the present inventor will be shown.

Test conditions Long-term 1'IIL aeration type combined septic tank treatment shown in the flow sheet of Figure 1 {h1/θms A3 g', i5 air 11''I capacity R10m'' Units shown in Figures 4 and 5, 20 units Specific gravity of contact material (76.7m%)
0.7 to 1 hole /, m3 with a filling rate of 74% or more, maintenance-free for about 2 months!Nl!
i + g t, then 4 (the results of qualitative analysis are shown in Table 11).

TABLE I

Since water content F was 0%, amount of biological sludge = sludge adhering to contact material = 10, suspended sludge = 3.
7 bags + 7. Results: The amount of biological sludge in the tank increased by approximately 2J%, which increased the purifier capacity and it can be assumed that the escape water BOD satisfied the design value.

[Brief explanation of the drawing]

Figure 1 is a treatment flow sheet, Figure 2 is a vertical front view of the aeration tank, Figure 3 is a vertical side view of the aeration tank, Figure 4 is an enlarged front view of the main parts, and Figure 5 is a plan view of Figure 4. It is a diagram. +1)...Diffuser ff, +21...
・4'+'W, (3)...unit, (3a)・
...Contact material, (3A) - Support frame (3B)...
・・Swim bladder (3C)・・Void part, (3D)・・・
...Zhong. 40 3D Fig. 5

Claims (1)

[Claims] (F/yI ratio in tank (2) equipped with O diffuser fl+ (
The amount of organic matter inflow/the amount of microorganisms) is calculated as follows: li (2) A float (3F3) is fixedly held on the upper part of the unit (3) or the support frame (3A), and the aeration tank is configured to be adjustable. A contact 4';4' (3a) is fixedly held at the lower part of the support frame (3A), a gap (3c) is formed therebetween, and a specific gravity adjusting weight (3D) is provided at the lower end of the support frame (3A). 1. A green air tank in the activated sludge sewage treatment method according to claim 0.