JPS5824394A - Deodorizing method - Google Patents

Abstract

PURPOSE:To deodrize malodorous gases efficiently with a simple device and easy operations by introducing said gases into a front stage wherein pH is >=7.1, then introducing the same into an aerobic rear stage wherein pH is <=6.9, thereby deodorizing the gases. CONSTITUTION:Waste water 1 is run together with the return sludge 2 from a settling tank 9 into a deodorizing section 4 in a bilogically treating tank 3 where pH is maintained at >=7.1. The mixed liq. in the section 4 is flowed into an aerating part 8 where the BOD, NH3, etc. in the waste water 1 are biologically oxidized and decomposed by the aeration of the air 11 from a blower B3. The malodorous gases 7 wherein the malodorous components such as ammonia, amines and the like which are not removed in the section 4 and are easily absorbable in acidic liq. remain are introduced into the 2nd deodorizing section 4' in the rear stage of the section 8 where pH is reduced, and the above-described malodorous components are removed by absorption, and oxidative decomposition.

Description

[Detailed Description of the Invention] This BA relates to a method for deodorizing foul-smelling gas through a biological treatment process. Conventionally, deodorizing methods for foul-smelling gas include acupuncture, acupuncture, alkaline agents, water extraction, and activated carbon. Various methods have been used, such as the ridge method using heavy oil as fuel, and the nine-combustion method using heavy oil as fuel, but all of them have the problem of requiring a large amount of deodorization costs.

It is an object of the present invention to solve the problems of the conventional methods and to provide a method that can deodorize easily and manually. In the method of deodorizing, the malodorous gas f: is introduced into the first step where the pn is 7.1 or more, and then further introduced into the aerobic second step where the pH is 6.9 or less for deodorization. An embodiment of the present invention, which is a method, will be described with reference to the drawings. In FIG. 1, wastewater 1 is treated with biological treatment 4! ! It flows into the ill deodorizing part number in 3. In this case, it is essential to maintain the U pn of 7.1 or higher within deodorization %4, and if the pn of the inflow liquid (return sludge - combined wastewater) to the deodorization s4 is less than 7.1, an alkaline agent ( After injecting liquid (NaOH, etc.) to adjust the pH level to 1, the gas and liquid come into contact with the foul-smelling gas from Blower B to remove foul-smelling components and gases with good water solubility that are absorbed by alkaline liquids, such as NZS, capron, and mercaptan. The mixed liquid in the deodorizing section 4 that absorbs the water then flows into the aeration section IK,
BOD in the said malodorous components and wastewater 1 by aeration of air 110 from blower Bs.

NH, etc. are biologically oxidized and decomposed. In addition, when the malodorous gas 6 is anoxic, the deodorizing section 41 becomes anaerobic, so that only the absorption of the pre-fouling odor components is performed, and when the 11t gas is entrained, the oxidative decomposition of Fi also proceeds at the same time.

Therefore, the reaction formula for the oxidative decomposition (nitrification reaction) of NHB in the aeration section is as follows: NH4" + 20
2 →2H◆+ Not + a2゜Hydrogen ion (H+
) is generated, which causes the pH of the mixed solution to decrease. As the concentration of H+ increases in the nitrification reaction, the pH in R11 decreases significantly after the aeration section 8, and the NH3 in the wastewater 1 increases.
1111! Depending on the situation, the pH will drop to about 5.0. In addition, since HaB is also oxidized by H2BOaK by the sulfur oxide, the mixed liquid is acidified.0 Ammonia, amines, etc. that were not absorbed and removed in the deodorizing section 4 are not absorbed by the alkaline liquid, but are absorbed by the all liquid. Malodorous gas with residual malodorous components 'I u p
It flows into the second deodorizing section 4' downstream of the aeration section 8 where the H content has decreased, and the malodorous components are absorbed and oxidized and decomposed.

The thus treated well-mixed liquid flows into the ore sedimentation hinoki, where it is stored separately, separated water 10 Fi is discharged, and returned to the deodorizing section 4 as settled sludge 8.

In addition, the deodorizing unit 11s4 should be provided with a cover plate for a 3m pipe so that the foul-smelling gas 7 above it does not leak into the atmosphere.
It is preferable to use a blower blower B2 to blow the malodorous gas 7 into the deodorizing section 4'.

Next, the nitrification removal volume I &amp;
In other words, wastewater l flows into the denitrification headquarters 12 under anaerobic conditions together with returned sludge z1 circulating H1 nitrification liquid 11', and NO2 and/or u in these flowing human liquids are NOs is converted to N2 by denitrification 1 as shown in the following equation.
As it is reductively decomposed into gas, hydroxide ions (on'''') are generated and the pH increases. As is clear from the above equation, a companion reducing agent is required to reduce the generated oxygen during the denitrification reaction. If there is a KBOD component in the wastewater 1, it can be used, and if there is a KBOD component in the wastewater 1, it can be used, and alcohol such as methanol or ethanol can be added separately as a reducing agent 1s to make up for the shortage. The reaction formula when methanol is used is shown below.

2NO, + 5CH, OH-+N,? +20H+9
1.0 Therefore, by the denitrification reaction, n OD, No
, de1iix where (NO2) was removed and the pH increased.
The liquid flows into part A 4 and absorbs a part of the malodorous components in the malodorous gas s. In this case, when the malodorous gas 6 is anoxic, it may be fed directly to the denitrification headquarters 13, and the anaerobic conditions will not be disturbed, but the odor gas will be accompanied by oxygen. Therefore, it is not preferable to use the deodorizing section 1 also as the derooming wood section 13 because the salt removal operation becomes troublesome.

Since the denitrification liquid FipH has increased throughout the above process, the addition of the alkaline agent to the deodorizing section 4 can be omitted or the amount added can be reduced. Thereafter, in the same manner as in the first hook, deodorization of the malodorous gas and oxidative decomposition of pollution-causing substances and absorbed malodorous components in the mixed liquid are carried out (the nitrification reaction proceeds in II gas s8), but the malodorous gas siL dissolved Oxygen in the nine-fold gas that comes into contact with the denitrifying liquid without M12m migrates into the liquid and the oxygen am of the malodorous gas 1 decreases, so the amount of dissolved oxygen in the mixed liquid U at the deodorizing section 4m end 0 is extremely small. become. Therefore, even if the circulating nitrification i[11' is returned to the denitrification headquarters 12, the anaerobic conditions will not be substantially disturbed.

In addition, although the outline of the equipment shown in Fig. 4 and 2 is shown in Fig. 4, the malodorous gas 7 is used for circulation of nitrification liquid by air lift (return of circulating nitrification liquid 11' to section 12). If #i' is used, the circulation pump can be omitted.

In this case, the above-mentioned salt mountain will not harm the minor conditions of the parent headquarters 12. Furthermore, Figure 3 shows the flow direction of the broken cord opening, and Figure 4 shows the flow direction of the 141ri diffuser pipe.

The pot of the present invention uses microorganisms to change the pH of the treated solution and utilizes the decomposition action of 11 compounds.Biological treatment methods that can apply such action include the above-mentioned activated sludge method, Biological treatment methods other than the nitrification and de-M bulking method can also be applied. Possible methods include the biofilm method, the rotating disk method (using activated carbon, sand, etc.), and the sprinkled P bed method. In addition, in these biological mill processes, it is preferable to provide a pH gradient along the flow direction of the treatment solution, and for this purpose, the treatment solution is put in a plug flow state9, and multiple steps are directly combined for treatment. Yes.

Next, examples of the present invention will be described.
As! A deodorizing treatment experiment was conducted using the apparatus shown in 5-. The capacity of Biological Kairi Hinoki 3 is 25 tons, and the first (-ki) Tsukuda 31 to the fifth (serious) cypress 3s are separated by partition plates with narrow water holes. C section is formed and the first sleeve 3. and fifth bucket 3. is used as a deodorizing section, and these 24I! A rounded board was installed to prevent IKU smelly gas from leaking into the atmosphere.

The wastewater 1 is stored in a storage tank 1', and air 11\tI! water 1
By heating the air inside the room, foul-smelling gas 6 is generated and wastewater is
Provided to the top of the first bucket 81 by the welfare pump lie! l, Sudden A gas ◆μ Blower B1 F) 1 & i I & $ s The internal liquid was aerated. The liquid II'i in the I & 1 tank 1 is allowed to flow through in order from the 2nd tank to the 4th NSn, and an alkaline agent (NaOH) is added to the 1st m8t, and an acid (Hct) is added to the 1st m8t.
) 17 were added to perform pIilJ adjustment.

In addition, it is Ot showing the cock for the 5', 15.16 and 17'ti pumps, a, b and C younger sister of Kame 51.
The amount of sedimentation im9 is 8 tons, and the settled sludge is 1 hinoki and 31 hinoki.
The MLSS of O biological treatment tank 3 was 72 as sludge returned to
The amount of air supplied to 00 Misaki 7t, Daiichi Rin 3, and 115411 was fixed at 5t7-, and the pH of these two tanks was set at three levels to examine the pH and deodorizing effect rA9#. The results are shown in the table below. From this table, the pH of Xie Lun 35 and No. It can be seen that effective deodorizing treatment can be performed by adjusting the temperature.

pH and deodorizing effect Hata a, a! 1 working inlet b = 1st cypress outlet C: 5th cypress outlet As stated above, according to the present invention, the deodorizing process can be performed accurately with simple operation and a simple device, and the amount of drug waste is small. Therefore, benefits such as being extremely energy-saving and economical can be obtained.

[Brief explanation of the drawing]

Rattan 1 - and 2nd Strain The system M Minggang showing each embodiment of the present invention, the 3rd garden is within the general plane of the device embodying the example in Figure 2,
4 Illustrations 3 A cross section taken along the line I-I in Figure 51 - A system description of the apparatus used in the present invention. Nagi Riko, 4.4'-Deodorizing Department, Sumi-Alkaline Agent, @,
? -...Odor gas, 8--Negative part, 9--Sedimentation, 10-Separated water, 11-! 2 ki, 1 m'・
- circulating nitrification liquid, [) - theory ffl bulk, if - reducing agent,
14-・Air diffuser, 11tel・, 1?
'-...Pump, 17-・Steel SB1~1ls-Prower-0 Patent developer: Ebara Infilco Co., Ltd. agent, patent attorney: Goyama Go - same: 11) Minoru

Claims (1)

[Scope of Claims] 1. In a method for making odor gases m odor by a biological treatment process of organic wastewater, the malodorous gases are introduced into a preliminary stage IiK having a pH of 7.1 or more, and then further having a pH of 6.9 or less. Deodorizing method by introducing into a pneumatic downstream stage @ t-Characterized deodorizing method 02, method 03 according to Scope 1a of the above-mentioned biological treatment step, in which the biological treatment step is based on nitrification and denitrification main stream
, Patent claim 0111i, wherein the first step is a denitrification main step
4. The method according to claim 81, wherein the biological treatment step is based on an activated sludge method or a biofilm method. Claim 11m1m1. The all liquid is separated from outside air. Method O described in Section 3, Section 3 or Section 4 of 6, @$1 Biological record processing step 6, which is carried out by bringing the physical liquid into a flow state or by combining multiple steps in series. The method according to claim 1, 2, 3, 4 or 5 of the claims 0