JPS61220795A - Treatment of high-concentration organic waste water - Google Patents

Abstract

PURPOSE:To treat waste water efficiently by adding iron sulfate, a high molecular flocculant and a porous inorg. additive to high-concn. org. waste water, rapidly flocculating the solid components in the org. waste water and treating the BOD source remaining in water in a modification vessel, etc. CONSTITUTION:Iron sulfate, a high molecular flocculant and a porous inorg. additive consisting essentially of 50-56% CaO, 20-30% SiO2, 7-10% Al2O3 and 4-10% SO3 are added to high-concn. org. waste water and mixed. The generated org. material-contg. flocs are separated and the obtained filtrate is brought into contact with putrefying bacteria and facultative anaerobes in a modification vessel under anaerobic conditions. Then the water is treated with facultative anaerobes in a bacterium effect vessel while blowing in air and then treated with aerobes in a group of aeration vessels under aerobic conditions. Consequently, solid components in org. waste water are rapidly flocculated, the BOD source remaining in water is treated in the modification vessel, the bacterium effect vessel and a group of the aeration vessels and the waste water is efficiently treated at low cost by small equipment without using any dilution water or with a small amt. of dilution water.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for efficiently and inexpensively treating highly concentrated organic wastewater, especially organic sludge. One method for treating highly concentrated organic wastewater such as organic sludge is to digest it in an anaerobic digestion tank heated to 30 to 35°C for 20 to 25 days.

The supernatant liquid and the digested sludge are separated, the supernatant liquid and the dehydrated filtrate of the sludge are combined, water is added to this, diluted 10 to 25 times, and the mixture is purified by activated sludge treatment or the watering hearth method. Good friend.

In addition, as another treatment method for highly concentrated organic wastewater, the wastewater is diluted with water 5 to 15 times and subjected to one, two or even three stages of aerobic digestion.

As a result of increasing the amount of wastewater by using a large amount of diluted water to reach a manageable concentration during treatment, large treatment facilities are required, which increases construction costs, requires a large installation area, and requires a large amount of wastewater. There were drawbacks such as the need for water and high operating costs.

Next, the second aerobic digestion treatment method has the same disadvantages as the anaerobic treatment method, since it requires a large amount of dilution water in addition to the disadvantage of producing a large amount of excess sludge noise.

[Means for solving problems]

In view of the current situation, the present invention has been developed to add undiluted iron sulfate, Ca050-56%, and SiO220-56% to highly concentrated organic wastewater.
A porous inorganic additive mainly composed of 30%, Al2O, 7-10%, and 8034-10% is mixed with a polymer flocculant, the resulting organic substance-containing aggregate is separated, and the F solution is sent to a denaturing tank. After bringing putrefactive bacteria and facultative anaerobic bacteria into contact with each other under anaerobic conditions, they were treated with facultative anaerobic bacteria while blowing air from the soil into the bacteria-effect tank. , and then treated with aerobic bacteria under aerobic conditions in an aeration tank group.

[Effect]

Since the present invention has the above configuration, in addition to iron sulfate and a polymer flocculant, Cab, AltosS, etc. are added to highly concentrated organic wastewater.
By adding a porous inorganic additive that is the main component to Os', the solid components in the organic wastewater are quickly coagulated, and the BOD source dissolved in large amounts in the organic wastewater is adsorbed by the additive. In addition, the BOD source remaining in the water is efficiently aerated through the denaturation tank and bacteria effect tank, which is efficient and requires no dilution water or only a small amount of dilution water, making it possible to use small equipment. [Embodiments] The present invention will be described in detail below with reference to illustrated embodiments.

In the figure, 1 is the highly concentrated organic wastewater to be treated,
This is wastewater containing a high concentration of BOD sources such as digested sludge, septic tank sludge, human waste, activated sludge, raw sewage sludge, etc., and is particularly sticky and has high alkalinity.
This is wastewater containing OD sources.

The organic wastewater 1 is stored in advance in a storage tank 2 in the form of only one type or a mixture of 12 or more types, and then is continuously supplied into the screen 4 by a liquid feeding pump 3.

This screen 4 has a diameter of about 5 in the organic wastewater 1.
A movable type (rotary type) that removes coarse particles 5 exceeding mf, for example, applying appropriate pressure to remove water and gold in coarse particles.
A fine screen is preferred. In this way, the organic wastewater from which coarse substances have been removed passes through the F liquid pipe 6 and is stored in the receiving tank 7.

Next, a fixed amount of organic wastewater is supplied from the receiving tank 7 to a coagulation mixing tank 9 by a pump 8. In the flocculation mixing tank 9, iron sulfate such as ferrous sulfate is first added, and then additives and polymer flocculants are added. Iron sulfate has a
It is desirable to set it to 15 inches. Addition of iron sulfate typically lowers the pH to about 5.5-6.5. Inorganic additives include CaO50-56%-310220-30%, AlzO
It is an inorganic substance whose main component is 7 to 10% and 8034 to 10%. Furthermore, Mg01~5%, F12031~
It is desirable to contain 5%. The polymer flocculant is preferably a cationic polymer, such as aniline resin hydrochloride, polythiourea hydrochloride, polyethyleneimine, polyvinylpyridine copolymer salt, polyacrylamide, and the like. It is desirable that the amount of the inorganic additive added is 10 to 30% based on the solid content of the wastewater, and the amount of the polymer flocculant is 0.05 to 0.5% based on the solid content of the wastewater.

The coagulation-mixing tank 9 is equipped with a stirring device, and in this tank, waste water is mixed with a coagulant, etc., and flocs having a diameter of about 3 to 4 mists are formed.

Next, the wastewater in which flocs have grown is supplied to a filter 11 using a pump 10t, where it is filtered and solids are removed. As the filtration machine, a pressurized belt press type filtration machine is preferable, but in addition, a filtration machine, a pressure filtration machine, a screw press, etc. can be used.

As mentioned above, besides iron sulfate, polymer flocculant.

Since the inorganic additive is used, the growth of flocs is promoted, and a large amount of organic components in the wastewater are adsorbed by the flocs, reducing the BOD source concentration in the filtrate by approximately y2 times. In addition, the wastewater filtration efficiency is extremely excellent, with 9.S.
It can be filtered at a high speed of S/m'-h.

Next, the filtrate from the filter 11 is directly introduced into the denaturing tank 13 without being diluted through the filtrate pipe 12't-. Putrefactive bacteria and facultative anaerobic bacteria are supplied to the inlet of the denaturation tank 13, and some of the treated water from the bacteria effect tank 14, which will be described later, is fed to the inlet of the denaturation tank 13 as it is or to the culture tank. It is supplied as a culture solution obtained through this process. Since air is not supplied within the denaturation tank 13, the wastewater is in an anaerobic state, and putrefactive bacteria are preferentially propagating therein. The inflowing wastewater contains various harmful bacteria and harmful substances that inhibit the function of facultative anaerobic bacteria active in the bacteria effect tank 14, which will be described later. It weakens, disappears, or decomposes in the presence of putrefactive bacteria and facultative anaerobes. Note that there is no need to adjust the pH within the denaturation tank 13.

In this manner, the number of facultative anaerobic bacteria in the wastewater is multiplied to about 4×10 5 to 6 cells/go in the presence of putrefactive bacteria. The spoilage bacteria that are mainly active in the denaturation tank 13 include Bacillus saptillus, Ptylus mesentericus, Bacillus mycoides, and Bacillus cielus. In addition, decomposition of the BOD source in the wastewater starts in this denaturation tank 13,
This facilitates decomposition in the bacterial effect tank 14, which will be described later.

The wastewater that has passed through the denaturation tank 13 is continuously introduced and air is supplied thereto. The wastewater changes from an anaerobic state to a facultative anaerobic state due to the oxygen in the supplied air, and the number of putrefying bacteria decreases.
Instead, the number of facultative anaerobes increases to about 5 x 10 cells/rnl. Phosphate helps propagation and activation of facultative anaerobic bacteria, and must be added if a toxic level of BOD is required and this amount is not present in the reeds or wastewater. In this way, as various facultative anaerobes propagate, the BOD source that serves as their nutritional source is decomposed by the various facultative anaerobes. In addition, if the pH is lower than 7.5, BO
This is not preferable because not only the removal rate of D is decreased, but also the removal rate of nitrogen and phosphorus is decreased, and a large amount of odor is generated.

It is desirable that the bacterial effect tank 14 be divided into at least two chambers by a porous partition plate or an iron partition plate disposed to allow waste water to flow therethrough. The BOD source in the wastewater 1 is decomposed by facultative anaerobic bacteria from a high-molecular state to a low-molecular state one after another by facultative anaerobic bacteria while continuously moving within the bacterial effect tank 14. Each facultative anaerobe is different; for example, facultative anaerobes that are involved in the decomposition of starch and proteins include bacteria of the genus Acetobacter and genus Micrococcus, but they are also involved in the decomposition of starch and protein, such as saccharides. Bacteria of the genus Streptococcus and genus Staphylococcus are used to decompose amino alcohol and amino alcohol, respectively. For example, the number of starch-degrading bacteria (such as Acetobacter) in the bacterial effect tank 14 is relatively small when it just enters the bacterial effect tank 14, but it gradually increases and reaches a peak, but as the starch decreases, On the other hand, saccharide-degrading bacteria (such as Streptococcus genus) gradually increase as the sugar content increases, and then decrease as the sugar content decreases.

As described above, the number of bacterial cells increases as nutrients increase, but the reproduction of bacterial cells often lags behind the increase in nutrients.

Therefore, a part of the wastewater in the vicinity where the number of starch-degrading bacteria is the largest is returned to the inlet of the bacteria-effect tank 14 to increase the number of starch-degrading bacteria at the inlet of the bacteria-effect tank 14. It is desirable to return some of the wastewater in the vicinity to the sugar production area. In this case, the point where the return water of the starch-degrading bacteria is taken out and the point where the return water of the saccharide-degrading bacteria is returned are close to each other, so that the flow of wastewater between the two locations is not significantly impeded in order to avoid a large amount of mixing between the two. It is desirable to provide a partition bt of approximately the same degree. The return water takeout position and return position are B in the wastewater.
BOD varies depending on the type of OD source, and wastewater has various BOD
When the source is included, it is desirable to use the average position.

The amount of oxygen supplied to the bacterial effect tank 14 is suppressed to an amount that is far below the amount of oxygen required by facultative anaerobic bacteria, and is preferably 5 to 10 Nm''/9 BOD/day in terms of air amount. In this way, because the amount of oxygen supplied is small, the oxygen demand of facultative anaerobes is 1.500 to 15.000■02
Although this shows a large value of /g bacterial cells/hr, the amount of oxygen supplied is only about 1,720 to 1/40 of the amount of oxygen required. Therefore, facultative anaerobes must also decompose oxygen-containing substances in wastewater to obtain oxygen;
In addition to nitrite ions, sulfate ions, and sulfite ions, it can also easily decompose phenol, cresol, melanin, carotene, lignin, etc., which were conventionally difficult to treat. After phenol etc. are removed from the wastewater, activated sludge treatment (aeration treatment) becomes easy.

The above oxygen demand (■0□/9 bacterial cells/hr) represents the amount of dissolved oxygen (1R9) that can be consumed by bacterial cells II in one hour. )
The amount of oxygen required at the time is 5 to 25 to 02/g·hr, whereas the amount of oxygen required by the bacteria in the bacteria effect tank 14 is a very large value as described above.

As the facultative anaerobic bacteria active in the bacteria effect tank 14, various types of bacteria such as the following are used, which decompose carbohydrates such as starch, oils and fats, proteins, lignin, sugars, amino acids, and others.

Clostridium (Clostridium peringus, Clostridium chaboai), Acetobacter,
Micrococcus spp., Streptococcus spp. (Rateitsukus streptococcii, Streptodeurans, Streptococciis), Staphylococcus spp. (Staphylococcus albus, Staphylococcus auras,
Staphylococcus citrius), Candida spp. (Candida tropicalius, Candida paracrusei), Basillasiaceae (Hacilius), Eumaisietes variants (Myxomycietes, Basidomycetes,
Desulfovibrio (Lilyraceae), Lactobacilius (Remibacterium, Cyclobacterium),
Pseudomonas elaginosa, Pseudomatorii, Niebacterium (Butylbacterium), Arthrobacterium
, Corynebacterium Scheer's family (Corynebacterium, Bacillus cellulosus, Pacilius thermophiliculus, Peptococcus spp., Shigella deicenteriae, Heptolobactilia) The above bacteria are just examples, and other bacteria can also be used. It is also possible to do so.

In this way, the highly concentrated BOD source is decomposed in the bacterium effect tank 14 without being diluted, and not only the BOD is reduced to 35 to 70 inches, but also nitrogen, phosphorus, and sulfur are decomposed.
Nitrogen content is reduced by 40-70%, phosphorus content is reduced by 80-90%, and sulfur content is reduced by 10-20%.

Next, the treated water treated in the bacteria effect tank 14 is transferred to the treated water pipe 1s.
It is introduced into the aeration tank group 17 after t. This consists of an aeration tank and a settling tank. If necessary, an aeration tank and a settling tank can be added.

The wastewater 1 has already passed through the denaturation tank 13 and the bacteria effect tank 14t, and the BOD source has been reduced to a low molecular weight, and it also contains phenol, melanin, and other substances that make activated sludge treatment difficult in the aeration tank.
Carotene, lignin, etc. have already been decomposed,
Furthermore, the organic matter in the BOD source is used for bacterial growth, and the bacterial cells are immediately digested by protozoa in the activated sludge, resulting in a mixed liquid BOD of 5 to 25 times that of the conventional activated sludge method. Even if the concentration is 4.000 to 7.800 ppm, processing can be performed at a sufficiently high speed. Note that if the wastewater from the bacteria effect tank 14 is still highly concentrated, it may be necessary to dilute it with returned treated water, etc., but the amount of dilution water can be significantly reduced, and the conventional activated sludge method 115 The following is fine. Therefore, the aeration tank and settling tank need to be smaller than those used in the conventional activated sludge method. In particular, in the aeration tank, Lv
Negative load 1.5 to 10, 9BOD/rlL3·day, LS load o, s to 1. Since it is okgnoD/JcgMLSS・day, the size of the aeration tank can be reduced to 115 to 1/20 compared to the conventional activated sludge method. Also,
The amount of air blown into the aeration tank is 10 to 25 Nm3/icg.
BOD・day, which is 115 to 1/day compared to the conventional activated sludge method.
7 and LJ), the air blowing energy can be significantly reduced. In addition, the amount of sludge produced was reduced to 0.805~0.29S S
/kfi B OD, which is 1/kfi of the conventional activated sludge method.
Since it is about 3 to 1/8, the running cost of dewatering is extremely low.

The MLSS mixed liquid treated in the aeration tank group 17 is transferred to the settling tank 18.
The supernatant water is sent to the treated water tank and discharged, and the MLSS water is returned to the aeration tank group 17 by the pump 19. Note that a part of the treated water in the treated water tank 20 is introduced into the aeration tank group 17 as needed, and the treated water from the bacteria effect tank 14 can be diluted according to changes in its concentration.

Specific example Human waste (BOD13.OOOppm) as high concentration wastewater
, SS 40.000ppm, C0D 4,500ppm
)'ir, and according to the process shown in Fig.
．． Screen 4. The mixture was introduced into a flocculation mixing tank 9 via a receiving tank 7.

In the coagulation mixing tank 9, add 15 to 16 g of 15% ferrous sulfate solution to the solid components of the wastewater and mix well.p:E(
6,5)・Furthermore, 2.0 to 35 g of additives with the composition shown in the table below and 0.1 g of polymer flocculant were added and mixed (pH 7.2
].

Next, filtration was performed at a high speed of 10w7m using a 0.35m wide belt press W filter. The filtration rate of the filtrate was 0.5 to 1.1 m''/m'·h, the thickness of the dehydrated sludge was 5 to 611 N1, and the water content of the dehydrated sludge was 62%. Filtration speed is 15-35kg5S
/rF? - No clogging of the door material occurred even after filtration. The BOD of the ν liquid was reduced to 6,400 ppm, the SS was reduced to 250 to 350 ppm, and the nitrogen content was removed by 30% and the phosphorus content by 60%. Because the moisture content of dehydrated sludge is low,
The amount of water needed to wash the equipment was small.

Next, the p liquid is passed through the denaturation tank 13 and the bacterial effect tank 14 to
OD't" was lowered to 2,300 to 4,500 ppm, and BOD treatment was performed in the next aeration tank group 17 by blowing a small amount of air at a processing capacity of 1.8 to 3/c9 BOD/m"-day. In conventional BσD processing, the Lv capacity load is 0.6 to 1.
．． 0 is given and set as a standard value of 9BOD/m"day, but in nature it has a capacity more than three times higher, 1.
8-3. SV
I is high at 60-100cr-7g, does not produce filamentous fungi, and Ls negative load conventionally weighs 0.05-0.2kg
BOD/#MLSS-day SS solids BOD load is 0
．． I was able to achieve this in 5 to 1 #BOD/#・MLSS・day.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, in addition to iron sulfate and a polymer flocculant, CaO+ is added to highly concentrated organic wastewater.
By adding a porous inorganic additive containing Altos I SOs as a main component, solid components in organic wastewater can be rapidly coagulated, making it possible to separate solid components at high speed and without clogging, Furthermore, the BOD source dissolved in a large amount in the organic wastewater is adsorbed by the additive, and the BOD source remaining in the water is replaced by easy-to-post-process bacterial cells in the subsequent denaturation tank and sterilization tank, and is then subjected to aeration treatment. It is possible to process efficiently and inexpensively with small equipment by not using dilution water at all or using only a small amount of dilution water.

[Brief explanation of drawings]

The drawings are process explanatory diagrams showing one embodiment of the present invention. Organic wastewater 2: Storage tank 3: Liquid pump 4 Niclean 5: Large items 6, 12: F liquid pipe 72 receiving tank 8.10.19: Bomb 9: Coagulation mixing tank 11 Nite filtration machine 13: Denaturation tank 14 Two-bacterial effect tank 15: Return pipe 16 Two treated water pipes 17: Aeration tank group 18 Two settling tanks 202 treatment tank

Claims (1)

[Claims] Iron sulfate, polymer flocculant, and CaO 5 in highly concentrated organic wastewater
0-56%, SiO_2 20-30%, Al_2O_
3 7-10% and SO_3 4-10% as main components are mixed with a porous inorganic additive, and the resulting organic matter-containing aggregates are separated. The resulting filtrate is treated with putrefactive bacteria and facultative anaerobic substances in a denaturation tank. After contacting with anaerobic bacteria under anaerobic conditions, it is treated with facultative anaerobic bacteria while blowing air in a bacteria effect tank, and then treated with aerobic bacteria under aerobic conditions in an aeration tank group. A method for treating highly concentrated organic wastewater.