JPS58109193A - Biological teratment for waste water - Google Patents

Abstract

PURPOSE:To perform nitrification of N compds. and removal of phosphates simultaneously and to permit efficient and stable maintenance and control of operations by bringing the waste water added with Ca agents and controlled of pH and BOD amts. into contact with specific solid particles under aerobic conditions. CONSTITUTION:Waste water, Ca agents and alkali agents are put into a treating tank 1 through pipes 6, 7, 8, and pH is controlled to 7-9.5 with a pH controller 13. The waste water ascends in an inside cylinder 2 together with solid particles 4 by the effect of the air through a pipe 3, and circulating flow in an arrow direction is formed. The particles 4 are, for example, ores, bone black, etc. on which microbial membranes and hydroxyapatite can be formed. The feed rate for the waste water is controlled automatically in such a way that the volume loading quantity of BOD by a BOD detector 14 attains <=1.5kg-BOD/m<2>.day. Then the N compds. in the waste water are oxidized down to nitrate N; at the same time, phosphates react with Ca and sticking of microorganisms thereon is eliminated at all or the phosphates are removed by growing crystals of hydroxyapatite on the surfaces of a part of the particles 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention #4 relates to a method for biological treatment of wastewater containing annealing elements, i1 compounds such as organic a nitrogen compounds, and phosphates, and in detail, surface #Cl1k By interposing solid particles with biofilm formation in the treatment tank, nitrogen compounds can be nitrified and phosphates can be removed in the treatment tank, thereby purifying wastewater efficiently (and economically). h% for one side*.

Generally, biological treatment methods are employed to purify wastewater containing nitrogen compounds and phosphorus. That is, phosphates are decomposed and removed by -11 of phosphoric acid oxidative decomposing microorganisms (hereinafter simply referred to as "phosphoric acid decomposers") under aerobic conditions. On the other hand, nitrogen compounds are oxidized to nitrate nitrogen (nitrification) under aerobic conditions by so-called nitrifying bacteria; The snow is introduced into a so-called de-squeeze, where it is removed by denitrifying bacteria under anaerobic conditions. In that case, since there are differences in the optimal growth conditions for the chloride salts and nitrifying bacteria, the oxidation tank C is used to remove the chloride salts, and the oxidation tank C is used to nitrate the chloride compounds. below"
It is normal for each tank to be installed independently from the nitrification tank.
Also, suspended sludge is usually used as a microbial source.

However, it is not economical to provide independent treatment steps that perform the same action of oxidation treatment by microorganisms (this is because the sludge concentration in each treatment layer s#c also increases beyond a certain level). On the other hand, in the case of the so-called activated sludge method using suspended sludge, the processing speed is extremely slow, the processing time is long, and large-capacity equipment is required, and the so-called bulking phenomenon occurs, causing the sludge to be processed. There are often cases where it is difficult to maintain and manage stable operation, such as leakage from the tank and a sudden drop in treatment efficiency.

The present invention has been made in view of these circumstances, and its purpose is to provide a wastewater treatment method that solves all of the above problems and enables efficient and stable operation management. Toh to try to provide.

However, the constitution of the present invention that achieves the above object is that the electrolyte compound in the wastewater is introduced into the treatment tank.

A method for simultaneous nitrification and phosphorus removal, in which solid particles capable of forming microbial films and hydroxyapatite on their surfaces are brought into contact with wastewater under aerobic conditions, while
Introducing the VV agent into the wastewater with IHIt & KN water O
Adjust the pH to 7-9Sa'C#ll and reduce the BOD in the treatment tank.
The key point is that the amount of wastewater introduced 17R4/& should be adjusted so that the amount of BOD in the wastewater is adjusted so that the volumetric negative amount is less than 1.6kll-BoD4rky.

The solid particles used in the present invention are particles on which microorganisms can grow and can produce hydroxyliapatite.
! The terminal velocity in the wastewater to be treated is 6 to 1100 m.
/hr and &, A (particle size: ao, oJs~1.O
m) may be used.1 For example, phosphate rock, azure, sand, etc.
Anthracite, activated carbon, coke.

Examples include granulated blast furnace slag, etc., and it is preferable that it has a v-value and is resistant to abrasion and crushing, and the amount of solid particles added is about 20 to 8 G (20 to 8 g) of the reaction area volume in the treatment tank. preferable. In other words, if the amount added is too small (20
If less than 1G) KF! , most of the solid particles have a microbial film attached to their surface, and the surface of the particle free of microorganisms is small, resulting in very little room for EFW growth. 9. This is because the dephosphorization ability is inhibited.On the other hand, if the amount added is too large (more than 1104), the friction between the solid particles will cause
This is due to the fact that the microbial film does not accumulate and the nitrification ability is inhibited.

In addition, the pH of the wastewater to be treated in 154 of the present invention was specified as 7 to 9.5 because, as is clear from the examples described later, on the acidic side, the phosphoric acid implant removal efficiency and nitrification rate of solid particles are both affected. On the other hand, at pH 9, fi or higher, the nitrification reaction is affected.

Calcium agents to be added to the wastewater to be treated include calcane force A/V um, hydroxide cuff 1/F um, etc., and the amount of addition is expected to be #i treatment SO kakin. Theoretical quantity C
Ca/PO4(eA/Jf:)=1.117) or more. In the case of using hydration oxidation power klVtsufu, JIc#i,
It is economical because the use of alkali agents for adjusting the pH of wastewater to be treated can be reduced.

Lol! In the military'let@, the 0BOD volume load in the tank is set to less than 1.6 kg-BOD-aay to maintain the system's phosphorus capacity at a high level. That is, B.O.
By suppressing the D volume load to 1.6 kg-BOD/m'・day or less, excessive growth of ROD oxidizing soda can be suppressed, and the aye degrading bacteria can be sufficiently attached to the particle surface. A room for growth and generation of hydroxyabatai F is ensured so as not to reduce the dephosphorization efficiency.

Hereinafter, the configuration and effects of the present invention will be explained in detail based on the drawings of the embodiments.

Figure 811 is an example of the equipment for sewing the present invention.
This is a WJKsP in which 1 is a treatment tank, 2 is an inner cylinder, and 8#i is a treatment tank that treats wastewater while suspending solid particles by airlift action caused by static electricity blowing.
Empty g & supply piping, 4 is solid particles, 6 is solid particle settling volume 11 (hereinafter simply referred to as "separation chamber")... % 6 is waste water supply piping s'# iCa agent supply piping, 8 is The alkali agent supply pipe 1G is a circulation pipe.

The treatment tank IP3 is filled with an apparent volume of solid particles 461 having an aerobic microbial film attached and grown on its surface, and an aerobic atmosphere is created by blowing air into the tank from the bottom. A separation wi5 is provided on the upper outer periphery of the treatment tank 1 so that the upper part of the treatment tank 1 and its bottom Its communicate with each other. The treated water after separation is led to a destaticizing tank (not shown in the figure) outside the system, while a part of the water is circulated to the upper part of the treatment tank 1 via piping 10. In the figure, a partition plate 11 is provided inside the separation chamber to enhance the effect of separating the solid particles 4 from settling. Further, as a means for stirring the solid particles 4 of the treatment tank IP9KFi and the waste water with air, the inner cylinder 2 and the above-mentioned air supply piping 8 are provided. Needless to say, oxygen can be supplied instead of air.

When treating wastewater using the equipment shown in Figure 1, Wc
Ifi, first, the wastewater containing MIg compounds and phosphates is passed through the pipe 6 by the wastewater supply pump 12 to the treatment tank lK.
Send. The feeding amount is set to be sufficient for the solid particles 4 in the treatment tank 1 to form a fluidized tank.

′i′)! Inject the K Ca agent into the coral tank 1 with 71 ha of piping, and the alkali agent into the treatment tank 1, and add alkali to adjust the pH to 7 to 9.6. .

The wastewater sent into the treatment tank 1 is passed through air piping 8 within the cypress 1.
Due to the air lift effect of the supplied air, a fluid circulation flow is formed which moves upwards inside the inner cylinder 2 together with the solid particles 4 and descends around the outer circumference of the inner cylinder 2. Also, the amount of wastewater sent is
The BOD volume load calculated based on the value determined by the BOD detector 14 is normally flc 1.6 kg-BCDA.
It is automatically adjusted so that If-da is 7 or less. During this time, the gg compounds in the wastewater are absorbed by the microbial film that has grown on the surface of the solid particles, resulting in nitrate nitrogen (NO3) as shown in the reaction formula below.
-N) is oxidized in the trench.

NH4 + 10 gog → NO3 - + NgO + 2H + At the same time, all the phosphorus in the wastewater reacts with <Ca as shown in the reaction formula below, and the following reaction formula is applied to the surface of solid particles to which microorganisms are not attached or are attached only partially. 1 as shown in 1. - removed by growing crystals of Doroki V apatite). .

50a”+jlPO4+OH- to a6(PO4)3-O
The above-mentioned treatment has been applied to the wastewater (treated water) #'i separation*6, and some of it is returned to piping 6 via piping 16, thereby returning to the biological treatment circulation system. is formed,
The other part is temporarily sent from the overflow part 16 to a destaticizing tank (not shown) through piping 9.

In addition, Figure 1g2 shows another example of the device, which is a fixed bed type processing tank filled with solid particles.
1B#i Air supply pipe, 14 is backwash water supply pipe, 1
5 is backwash water discharge pipe% 16 is waste water supply pipe, 17t
JCa agent supply piping, 18 is alkali agent supply piping%1
9 is a pipe for discharging treated water. Since the eel tank shown in this figure adopts a method in which the solid particles are kept stationary in a certain part (the lower side of the processing tank 1), it goes without saying that a separation chamber 6 is provided as shown in Fig. 1. , compared to the device shown in Figure 1, the basic structure fd! is based on the difference in the contact method between wastewater and solid particles. There is a big difference. That is, in the installation of the first LN, an interior 182 and a separation chamber 6 are provided, whereas in the apparatus shown in FIG. However, there are other incidental structures for piping systems and measurement control systems! There's nothing clever about it.

Therefore, when treating wastewater using the device shown in Figure 111, the same operations as the wastewater treatment operation using the device shown in Figure 1 described above can be performed, but the head loss of filling w112 is caused by long-term operation. If the amount of water increases and the smooth passage of wastewater becomes obstructed, the supply of wastewater is stopped, and backwash water is sent to the bottom of the treatment tank 11 from the pipe 14* to clean the inside of the filling chamber 12. By backflowing] the clogging between solid particles is removed, and this backwash water is sent to the upper part of the treatment tank 11 through the general public pipe 1.
It should be discharged from 6.

The biological treatment method for wastewater related to Kippatsu 111 is as described above! The point is that the oxidation of carbon oxides and the oxidative decomposition reaction of phosphorus wood, which are carried out by microorganisms attached to the surface of solid particles in the treatment tank, can be controlled with simple operations. Since nitrification and removal of phosphates can be carried out simultaneously in the same treatment chamber, the removal of the above-mentioned amount of waste water can be carried out stably, efficiently and quickly over a long period of time. Furthermore, all the solid particles filled in the treatment tank remain in the tank and are effectively used for biological reactions, which is economical.

If the method of detoxification is used effectively, each 11j11 water detoxification process can be carried out more effectively, and the following 2.80
Examples based on drawings! explain.

Figure 8 shows a flowchart (V-) for detoxifying raw wastewater with a low BOD concentration, such as secondary treated sewage water. After the nitrification and dephosphorization are carried out simultaneously by blowing and the addition of KCa agent and alkali agent, methanol is added in denitrification tank B and reduced with ``or2 gas [1]. The excess methanol that does not participate in the de-11ff reaction is complexed and decomposed in the re-aeration tank C, and the wastewater here is subjected to an initial decomposition process. *For the denitrification tank B and the re-aeration WIC in the case of ζO, biological treatment methods including the biofilm method and the sludge method may be adopted.

Also, Figure 4 shows the flow V when treating primary sewage treatment water, waste physical site leachate, and each apple desorbed liquid from the sludge treatment process.
- 4, the raw wastewater is blown with air in the preliminary aeration tank AQ to remove most of the BOD components, and then sent to the apparatus A for implementing the method of the present invention. As shown in the figure, the processing of the aircraft was carried out in the equipment fA at the JI＊eO building.
Djll load! , 5 kft-EDDl&.71 ay or less can be omitted.

I! As shown in Figure 6, the preliminary aeration tank AQ is
A preliminary denitrification tank BQ is installed in front of the device A, and the nitrification liquid from the device A is circulated, and the BOD components in the raw wastewater are effectively used to carry out preliminary denitrification.〉Amount of methanol added in the denitrification tank B can be saved. Also spare #1. m tank B
H1 by effectively using the free 9 UI# space in □
l! It is also possible to reduce the amount of cleaning agent A/'j1 used in a.

In this case as well, the BODJIL load suppression operation in device A is the same as the suppression operation. Preliminary aeration tank AQ and preliminary denitrification tank B
For both methods, the biofilm method, which does not require sludge return, is preferable, and it is possible to use any type of biofilm tSO, such as the rotating disk method or intermediate oxidation method.

Examples of the present invention will be shown below.

C Example 1) After carrying out a treatment experiment under the following conditions using the apparatus shown in FIG. 1, the water quality measurement results of the treated water were as shown in Table 1, with a total of 6 and 9 results.

- Experimental conditions Treatment tank shape: square with a side length of 86 m and a depth of 1 Jm
, volume 10/.

Solid particles: Contact pre-treatment with phosphorus #Mombo solution!
l slag (particle size 0.1-0.2 swφ) was used, and the amount added was 21 (particle concentration 20 tatami).

Uses synthetic wastewater equivalent to raw water and secondary sewage treated water (components: Beptone, NH4C/, KH2PO4, NaC/*M
g804. NaHCO3), BOD+ = 15 ppm.

NH3-N-20ppm, PO4-P =8J pp
n.

M alkalinity W10011pm (as CaC03),
(NOx-N)+(NO3-N)<0.21)I
> 111 water increase fIA = 25°C pH in the tank: 9 Ca addition amount: IQOppm (added CaC7gf# liquid) retention Ill: 8G min (Ig wastewater state amount 20/
/hrNH3-N negative 11r: 1 kg-N113-N
/m'-da7BOD negative stomach: 0.7kg-BOD/
vd-d&7 Result 11!1 Table As is obvious, ]PO4- in the raw wastewater
Immediately after the start of water flow, P is removed at Kt below Q, Rppm, while the nitrification reaction progresses and NH3-N (No fertilizer + N0
3) Even after being oxidized to -N, the po4-P removal ability does not change; in particular, the removal of KPO4-P and NH
It was confirmed that the nitrification of 3-N was carried out stably. (5jjE Example) Using the equipment shown in Figure 2, the water quality measurement results of the treated water were as follows: The information was as shown in Table 2.

Experimental conditions: Shape of treatment tank: Cylindrical type with inner diameter of 10G-, height of 1t, 8m.
.

Filling chamber height: 1.26 mn Filler: Granulated blast furnace slag (particle size l~6.7 tm) was subjected to contact pretreatment in the same manner as in Example 1.
The amount added is 10/.

Raw water flit: 800 //lay, LV=R
8 m/lay, 5 V-1,261/hr The treated water temperature, tank pH, and amount of Ca added were all the same conditions as in Example 1. @NH3-N load 0.6kg/rr
/-day ・BOD load 0.2-0.6 kg7y
d' It was stuffy, and I passed water through it 1 [11 times a day] and backwashed it. In measuring the water quality of the treated water, 9 treated water, which had completely progressed to nitrification and reached a steady M@, was targeted.

As shown in Table 2, NH3-N and PO4-P in the raw wastewater were efficiently removed, and NH3-N and PO4-P in the raw wastewater were removed well (by the filtration action of the filling chamber described above). It was confirmed that

(Example 8) Based on the flowchart of wastewater detoxification treatment shown in Fig. 8, the following procedure is carried out. Continuous wastewater treatment experiments were conducted, and the results of water quality measurement of the obtained treated water are shown in Table 8.

The same 4 solid particles as in Example 1 were used for #C in the apparatus A and the apparatus 1A. Denitrification tank 1 is bird-shaped with a side length of 1705W, water depth of 170SNW, and volume of 6TOII.
This is an anaerobic treatment tank with t. In addition, in the denitrification tank BK, 0.761 of sand with a particle size of 0.2 to G and a wφ was added as solid particles (
The sand was suspended and suspended by a mechanical stirring means using a rotary machine. The re-aeration tank C has the same structure as the device 1A, is rectangular with a side of 50 cm, has a water depth of 1600 w, a volume of 41 cm, and has a solid particle size of 0.2 to 0.8 s11.
Add 0.8/φ sand (particle concentration OTo>shi).

Secondary treated sewage water is used as raw wastewater, and each of the above [A]
, The 4t & coral conditions in B and C were set like a queen, and the water temperature in both I/C treatments was adjusted to 5°C.

Apparatus 1A pH: 8.6, Ca*7Jljk: 100
ppm (100 ppm solution added), residence time 280 minutes,
NH3-N*load; l kg-NH3-N/m's d
ay, BOD load: Q, 4-0.8kg BOD/
7F/”+la7 Glaring Mouse Toumachi Meno vyt=Additional 1k: II O Rabbit 1 fl *Residence time: 16 minutes Re-aeration tank C Residence time: 16 minutes If the water quality measurement of treated water fails, after the start of operation. The target was Kusho Rumi, who became a regular cane a after one month.

Result 1st I! ! l! As is clear, the total length of 1 m (T-N) in the treated water is 1)]911 or less], I! <po4
-P2O, 1NO, II pp! ltonashi, raw wastewater O
It was confirmed that more than 961 of the II bulky gold compound phosphorous compounds were effectively removed, and that the removal of undocumented materials was effectively carried out.

[Brief explanation of the drawing]

Figure 11!1 is an explanatory diagram of one embodiment of an apparatus for carrying out the present invention, Figure 2 is an explanatory diagram of another embodiment, and Figures 1 to 6 illustrate nine different types of wastewater treatment using the method of the present invention. Flow F-) are shown respectively. 1... Treatment tank 2... Inner cylinder 8... Air supply pipe 4... Solid particles 6... Raw wastewater supply pipe
7... Piping for C& agent supply 8... Piping for alkali V agent supply 18-IHIlB meter 14-B OD detection meter A...
・Example equipment 'III B--Denitrification tank C--Reareration tank outlet Kobe Steel, Ltd.

Claims (1)

[Claims] (1) A method that simultaneously nitrates nitrogen compounds and removes phosphates from wastewater introduced into a treatment tank, in which solid particles capable of growing biofilm and hydroxyapatite on their surfaces are grown under aerobic conditions. At the same time, a calcium agent was added to the introduced wastewater, and the wastewater was brought into contact with the wastewater (from 7 to
9.5, and the BOD volume load in the treatment tank is 1
, b) A biological treatment method for wastewater, characterized in that the amount of wastewater introduced or the amount of BOD in the wastewater is adjusted so that the amount becomes less than "It"""/d-681.