KR19980034060A - Two stage anaerobic fermentation method of organic waste liquid - Google Patents

Abstract

The present invention relates to a two-step anaerobic fermentation method used in the treatment of organic waste liquids, such as manure, and a fermentation tank used therein. In the two-step anaerobic fermentation method of the present invention, two-step anaerobic fermentation of the organic waste liquid consisting of fermenting organic waste liquid in the first fermentation tank to produce organic acid, and then transferring the organic waste liquid having undergone the organic acid fermentation step to the second fermentation tank to ferment methane production. The method of claim 2, wherein the transfer of the organic waste liquid from the first fermentation tank to the second fermentation tank is carried out through the sludge layer formed at the bottom of the second fermentation tank to the sludge layer formed at the bottom of the first fermentation tank. Consists of steps. And, the second stage anaerobic fermentation tank according to the present invention and the fermentation tank for fermenting the manure; A diaphragm installed in the fermentation tank so as to separate and form an organic acid producing fermentation portion and a methane producing fermentation portion, and having a sludge distribution port for distributing sludge at a lower portion thereof; A sludge collection unit for collecting sludge on the bottom of the methane-producing fermentation unit of the fermentation tank; Sludge discharge port for discharging the sludge of the sludge collection unit to the outside.

Description

Two stage anaerobic fermentation method of organic waste liquid

The present invention relates to an anaerobic fermentation method used to treat organic waste liquids, such as manure of livestock, and a fermentation tank used therein. More specifically, a two-stage anaerobic fermentation method in which acid-producing fermentation and methane-producing fermentation are performed separately and a fermentation tank used therein It is about.

In general, anaerobic fermentation is a wastewater treatment method in which organic waste liquids such as livestock manure, urban sewage, agricultural and marine products, food by-products and their wastewater are decomposed and treated by microorganisms under anaerobic conditions. It is a wastewater treatment method that produces fermentation gas by fermenting organic matter in fermentation tank and decomposing organic matter.

This general anaerobic fermentation process can be basically divided into two stages: organic acid production fermentation step and methane production fermentation step.Because the physiological characteristics and nutritional composition of microorganisms acting in each step are different, the same fermentation step is not separated. In the first stage anaerobic fermentation method performed in fermentation tank, it is impossible to adjust each stage to the optimum state, but even though the structure of fermentation tank used is simple, treatment efficiency is low and concentration of discharged water (BOD, COD, total solids, nitrogen, etc.) It is high, and subsequent processing is difficult. In addition, the two-stage anaerobic fermentation method and fermenter used for separating organic acid-produced fermentation step and methane-produced fermentation step have been developed to improve these shortcomings, but it is difficult to operate and it is not stable because it is sensitive to load and generation of influent wastewater. In addition, it is not practically used because of its low efficiency.

The present invention has been made to solve the problems of the prior art as described above, the object of the present invention is the simple two-phase anaerobic fermentation of the waste water treatment efficiency to maintain a stable fermentation in spite of the change of the influent wastewater is simple to carry out It provides a method and a fermenter used for the same.

Other objects, advantages and novelties of the present invention will be readily apparent from the following description.

1 is a longitudinal sectional view of a two-stage anaerobic fermentation tank according to the present invention.

Figure 2 is a cross-sectional view of the two-stage anaerobic fermentation tank according to the present invention.

Figure 3 is a diagram showing the change in the sludge layer height after mixing the pig manure in the acid production tank of the two-stage anaerobic fermentation tank according to the present invention.

Figure 4 is a diagram showing the process of using the process including the two-step anaerobic fermentation method of the present invention to the manure from the pig barn to finally withdrawal or discharge or composting.

In order to achieve the above object, according to the present invention, the organic waste liquid in the first fermentation tank organic waste production fermentation, and then the organic waste liquid passed through the organic acid production fermentation step to the second fermentation tank organic waste liquid consisting of methane production fermentation A two-step anaerobic fermentation method is provided. At this time, the transfer of the organic waste liquid from the first fermentation tank to the second fermentation tank is made through the sludge layer formed in the lower portion of the second fermentation tank from the sludge layer formed in the lower portion of the first fermentation tank.

As described above, the two-step anaerobic fermentation is performed by separating the organic acid-producing fermentation step and the methane-producing fermentation step in order to maximize the characteristics of the anaerobic microorganism as described above. That is, the first fermentation tank in which the organic acid-produced fermentation occurs mainly adjusts the pH of the fermenter to the optimum pH6.3-6.8 of the acid-producing group so that the acid-producing bacteria inhabit. This pH control is to increase the load rate of the first fermentation acid production tank to increase the amount of organic matter that can be decomposed by acid-producing bacteria can be active in the production of organic acids can be kept low pH. On the other hand, in the second fermentation tank in which methane-producing fermentation takes place, the pH of the fermenter is adjusted to be close to the optimum pH7.3-7.5 of methane-producing bacteria so that methane-producing bacteria inhabit. Such pH adjustment is possible by lowering the load rate of the second fermentation tank which is a methane production tank. This pH control is also achieved by simultaneously controlling the hydraulic retention time in each fermenter of the organic waste liquor.

It is preferable that the ratio of the hydraulic residence time of the organic waste liquid in the acid production and the methane production tank is about 4:11.

However, the ratio can be changed depending on various factors such as the concentration of organic matter in the waste liquid to be added. For example, the higher the concentration of organic matter in the waste to be treated, the longer the hydraulic retention time in the acid production tank, the higher the hydraulic retention time in the acid production tank, and the less Increase. In addition, when the amount of carbon is relatively lower than that of nitrogen, the hydraulic retention time is increased in the acid production tank. The sum of the hydraulic retention times in the acid and methane production tanks should be approximately 15 days, but longer if the concentration of organic matter in the waste liquid is higher and shorter if it is low.

The adjustment of the hydraulic residence time as described above can be easily known to those of ordinary skill in the art.

In the present invention, the agitation of the waste liquid is important in the two-step anaerobic presentation method of the organic waste liquid. Acid-producing bacteria in the acid-producing tank decompose organic materials to produce substances such as volatile fatty acids. When the organic matter is abundant, acid production is promoted and acidity is easily lowered below the optimum pH, thereby lowering the vitality of the acid-producing bacteria. In this case, if the agitation is performed, acid diffusion (dilution) generated around the acid-producing bacteria occurs, thereby increasing the pH of the strain.In addition, when the nutrient source (organic matter) is consumed and the nutrient source is insufficient, a nutrient source is placed around the microorganism. There is also the effect of supply. It also has the effect of preventing the sludge from hardening. Therefore, it is necessary to stir the waste liquid in the acid production tank, and not only the supernatant but also the sludge layer may be stirred. However, the agitation in the acid production bath is sufficient to be performed intermittently short for the above purpose. This also helps save energy. On the other hand, the waste liquid in the methane production tank is divided into supernatant and bud (sludge layer). Methane-producing bacteria inhabit this sludge layer and methane is produced most actively in this sludge layer. Therefore, when this sludge layer is destroyed, the living base of methane producing bacteria is similar to that of the methane producing bacterium. In other words, if the sludge layer is destroyed, the decomposition rate of organic matter is reduced. In addition, methane-producing bacteria are very long, with generation times of three days to one week, so that frequent stirring results in the outflow of microorganisms. Therefore, in the methane production tank, it is preferable to avoid stirring as much as possible so as not to destroy the sludge layer.

However, slight agitation can increase the decomposition efficiency. That is, by stirring and removing methane, which is an inhibitor of methane-producing bacteria, the vitality of the microorganisms can be increased, and nutrient sources can be supplied around the microorganisms by stirring. In addition, in the two-step anaerobic fermentation method, the first fermentation tank and the second fermentation tank may be operated continuously.

According to the two-step anaerobic fermentation method of the present invention, the waste liquid which has undergone the organic acid-producing fermentation step in the first fermentation tank is transferred to the sludge layer formed in the lower portion of the second fermentation tank via the sludge layer formed in the lower portion of the first fermentation tank. The reason for supplying the waste liquor from the first fermentation tank to the sludge layer formed in the lower portion of the second fermentation tank is that almost all of the methane production regulations of the second fermentation tank are inhabited. This is to allow sufficient fermentation to decompose the organic acid as high as possible. In addition, the acid production tank may be stirred not only the supernatant but also the sludge layer, and thus, a sufficiently mixed waste solution may be supplied to the sludge layer formed at the bottom of the methane production tank, but as described above, stirring in the acid production tank is intermittently 2-3 minutes. It is enough to carry out this, and this helps to save energy. In the acid production tank, the agitation is minimized to the required range, and the sludge layer is formed so that the waste liquid after the organic acid-generating fermentation step passes through the sludge layer to generate methane. It is desirable to be transferred to the sludge layer of the bath. In the methane production tank, the supernatant is discharged out of the fermentation tank. The two-stage anaerobic fermentation method is a major advantage of maintaining the stability of the high anaerobic fermentation regardless of the load and properties of the influent wastewater, and has the advantage of increasing the treatment efficiency (BOD, nitrogen), and shorten the treatment period, etc. .

In addition, the slurry accumulated in the lower portion of the second fermentation tank is discharged out as needed. The organic waste liquid includes livestock manure, servings, municipal sewage, agricultural and marine products, food processing by-products and wastewater thereof. The organic waste liquid is advantageously livestock manure.

According to the present invention, the waste liquid subjected to the two-step anaerobic fermentation fixation may be precipitated in a settling tank, divided into a supernatant and a slurry, and then returned to the first fermentation tank. The anaerobic fermentation waste liquid, which has been subjected to the conventional anaerobic fermentation process, is a high-soil waste liquid having a BOD of about 6000 ppm. This concentration is well above the 3000 ppm BOD, the economic upper limit of aerobic fermentation, a subsequent process of purification. For this reason, wastewater after anaerobic fermentation requires dilution. However, the present invention is a process requiring no dilution water. In other words, the waste liquid after the methane production fermentation step of the two-step anaerobic fermentation process of the present invention is much lower BOD than the waste liquid after the first stage anaerobic fermentation, but still contains a considerable amount of solids to increase the BOD in the waste liquid. Therefore, by separating the solids by sedimentation, the solid sludge is added to the first fermentation tank, which is an advantageous fermentation tank, thereby reducing the BOD of the anaerobic fermentation liquor and reducing the load of the aerobic fermentation, thereby making it unnecessary to add water and dilute it. As a result, anaerobic sludge reduction is effective.

In addition, even in the properties of the organic acid fermentation tank to increase the acidity of the organic acid fermentation tank to maintain a low acidity to an appropriate acidity to increase the activity of acid-producing microorganisms can obtain a high decomposition efficiency. In addition, this process allows the liquid material with a low load in the wastewater to have a short hydraulic retention time, while the solids increase the residence time to improve the treatment efficiency of the wastewater.

The two-stage anaerobic fermentation process may further include other processes before and after the process and may be used for organic anaerobic treatment. For example, the organic waste liquid that has undergone the two-step anaerobic fermentation process may be aerobic fermented in another fermenter. At this time, a portion of the supernatant of the organic acid fermentation tank may be supplied to the aerobic fermentation tank to improve the ratio of carbon and nitrogen in aerobic fermentation. In general, the effluent from the anaerobic fermentation has a high BOD and has a disadvantage in that the decomposition of the carbon source is high but the decomposition of nitrogen is hardly achieved during the anaerobic fermentation decomposition process, which is the same in the two-stage anaerobic fermentation of the present invention.

Such waste liquid is a factor that hinders the efficiency of aerobic fermentation, which is a subsequent process. That is, the concentration of nitrogen is high, but relatively lacking a carbon source that can be processed by microorganisms. However, the supernatant of acid-produced fermentation during the two-stage anaerobic fermentation contains a lot of carbon sources that are easily decomposed, which can reduce the shortage of carbon sources compared to nitrogen when mixed with the anaerobic fermentation waste liquid. It can be maximized. In addition, by transferring a portion of the supernatant of the acid-producing fermentation tank to the aerobic fermentation tank, it is possible to reduce the size of the facilities of anaerobic and aerobic fermentation tank, to reduce the fermentation time of anaerobic fermentation, to simplify the process of aerobic fermentation, and to reduce the loading rate of aerobic fermentation. In addition, the acid-produced fermentation is pH 6.3-6.5 and the concentration of the effluent from the methane-produced fermentation step is pH 7.3-7.5, so mixing them can be close to the optimum pH 7 of aerobic fermentation.

On the other hand, a method of improving the aerobic fermentation efficiency by adding a part of the original waste liquid to the anaerobic fermentation waste liquid, which is a conventional method, is also added with the decomposable carbohydrates and solids in the waste waste. Although the ratio was improved, the load was greatly increased, causing the efficiency of aerobic fermentation to decrease.

In the embodiment of the present invention as described above, the supernatant of the organic acid-producing fermentation tank transported from the aerobic fermentation tank has a relationship of 1: 4-1: 8 in volume ratio with respect to the organic waste liquid which has undergone the methane production fermentation step introduced into the aerobic fermentation tank. It is preferable in the balance between nitrogen and nitrogen.

According to still another aspect of the present invention, there is provided a fermentation tank for fermenting manure; A diaphragm installed in the fermentation tank so as to separate and form an organic acid producing fermentation portion and a methane producing fermentation portion, and having a sludge distribution port for distributing sludge at a lower portion thereof; A sludge collection unit for collecting sludge on the bottom of the methane-producing fermentation unit of the fermentation tank; It relates to a two-stage anaerobic fermentation tank comprising a sludge discharge port for discharging the sludge of the sludge collection unit to the outside.

Hereinafter, with reference to the accompanying drawings for the purpose of illustrating a two-step anaerobic fermentation tank of the present invention.

1 is a longitudinal sectional view of a two-stage anaerobic fermentation tank of the present invention. As shown in Figure 1, the anaerobic fermentation tank according to the present invention and the fermentation tank (1) for fermenting the manure; A diaphragm 9 installed in the fermentation tank so as to separate and form the organic acid producing and fermenting portion 3 and the methane producing fermentation portion 5 and having a sludge distribution port 7 for distributing sludge in the lower portion; A sludge collection unit 11 for collecting sludge at the bottom of the methane-producing fermentation unit of the fermentation tank; It consists of a two-stage anaerobic fermentation tank having a sludge outlet 13 for discharging the sludge of the sludge collection unit to the outside.

Two-stage anaerobic fermentation tank of the present invention can be made of a variety of materials, such as concrete, iron, FRP, scale can also be produced in a variety of sizes and treatment capacity. In addition, it can be made in various forms, such as a cube, a cylinder.

The diaphragm serves to distinguish between the organic acid producing fermentation portion and the methane producing fermentation portion, and also determines the ratio of the hydraulic retention time of the organic acid generating fermentation portion and the methane producing fermentation portion. The pH of the waste liquid from the organic acid producing fermentation and the methane producing fermentation is greatly influenced by the hydraulic retention time, and the success or failure of the two-stage anaerobic fermentation is influenced.

The sludge is slanted to the sludge collecting unit 11 installed on the bottom of the methane producing fermentation unit 5 on the bottom of the fermentation tank 1 so as to slide smoothly.

The diaphragm is provided with a gas flow section 15 for gas flow between the organic acid generating fermentation section 3 and the methane generating fermentation section 5 in addition to the sludge distribution port 7 formed at the bottom.

In addition, a boiler using methane gas generated during anaerobic fermentation is installed outside to maintain the temperature inside the fermentation tank, and a heating pipe or heating panel is installed inside the fermentation tank as a hot water circulation heating device.

In addition, an acid pipe is installed where the sludge layer in the lower part of the fermenter is formed in order to mix the contents, and the contents are mixed by circulating the fermentation gas in the upper part of the fermenter by a blower and brought into the lower tube.

In addition, a waste liquid inlet (17) for injecting waste liquid to the organic acid-producing fermentation side and a supernatant outlet (19) for discharging the supernatant of the methane-producing fermentation is installed at the methane-producing fermentation side, and anaerobic at the upper part of the fermentation tank. A gas outlet 21 for discharging the gas produced during fermentation is provided. Fermentation gas is supplied to the methane boiler and blower from this gas outlet.

The two-stage anaerobic fermentation tank of the present invention can be operated by intermittent inflow and continuous combustion inflow, etc., depending on the type of inflow waste, and the outflow of waste liquid after anaerobic fermentation can also be made simultaneously with the inflow of waste.

As can be seen from the above, the two-stage anaerobic fermentation tank of the present invention is extremely simple in structure and divides the compartments according to the characteristics of a general box-shaped, cylindrical, etc. structure and forms a tunnel under the partition to make up the part of the contents. As a structure that allows the movement, the organic acid producing fermentation step and the methane producing fermentation step can be easily separated and operated to maximize the treatment efficiency.

The present invention will be described in more detail with reference to the following Examples. However, the present invention is not limited to the following examples.

EXAMPLE

Example 1-a

This example was performed to compare two stage anaerobic fermentation and conventional one stage anaerobic fermentation. Pig manure was treated using a two-stage anaerobic fermentation tank consisting of a polyethylene container (actual fermentation capacity) with a capacity of 1 ton of the structure as shown in FIGS. 1 and 2. The characteristics of the used manure are shown in Table 1. The volume ratio of the acid production tank and the methane production tank was 4:11. The operating conditions were that the residence time of the liquid substance was 15 days, the hydraulic residence time in the acid production tank was 4 days, and the hydraulic residence time in the methane production tank was 11 days. Pig manure was divided into 8 groups of 53.3L per day in acid production tank. And, the supernatant was discharged from the methane production tank 45L per day, which is about 85% of the pig manure input. The remainder was released as steam, methane and sludge. The temperature of the fermenter was maintained at 39 ° C. of mesophilic fermentation.

Mixing (stirring) of pig manure in the acid production tank and the methane production tank was performed by circulating methane gas produced during anaerobic fermentation using acid pipes installed inside the fermentation tank, and both the acid production tank and the methane production tank were intermittently sludge solidified. It was over a short time of 2-3 minutes only. After stirring the separation of the supernatant and sludge layer, ie the solids took 20-30 minutes. The sludge was discharged out of the methane production tank.

Conventional one-stage anaerobic fermentation experiments used fermenters of the same size and structure as the two-stage anaerobic fermentation, but did not install only diaphragms. The residence time was 15 days. Other conditions were the same as the two stage anaerobic fermentation. The results are shown in Table 2. The results in Table 2 were obtained about 30 days after operation by fermentation.

Example 1-b

This example was performed to determine the optimal residence time in the acid production tank and the methane production tank during two-stage anaerobic fermentation. Two-stage anaerobic fermentation was used by connecting two vessels of 8L capacity acrylic container (6L actual fermentation capacity) up and down. The upper one was used as an acid-producing fermenter and the lower one was used as a methane-producing fermenter. The operating conditions were the total residence time of the liquid material 15 days, and the ratio of the residence time in the acid-producing fermentation tank and the methane fermentation tank was as shown in Table 3. Therefore, the case where the input time and the flow rate in each fermenter are 4 days in the acid-producing fermentation tank and 11 days in the methane-producing fermenter will be explained as follows.

Acid production tank: Dosage 1.5L / day (6L / 4 days), outflow: Approximately 1.5L day, methane production tank: Dosage 0.552 / day (6L / 11 days), outflow about 0.552 (day) More than the input from the production tank, the rest was discarded. The effluent of the acid production tank was introduced into the sludge layer of the methane production tank and the supernatant was discharged as treated water from the mesan production tank. The temperature of the fermenter was maintained at 39 ° C. of the temperature zone fermentation in the external tank basic formula. As a supplementary device, methane gas from the fermentation tank was stored in a gas collection tank to measure the amount of gas generated. An acid engine was installed inside the anaerobic fermentation tank to circulate the methane gas and the inside was stirred. Stirring was performed intermittently over a short period of 2-3 minutes in both the acid and methane production tanks. It was the same as used in Example 1-a used.

Conventional one-step anaerobic fermentation was carried out using an acrylic container (actual fermentation volume 6L) 11 having a volume of 8L. The residence time was 15 days. Other conditions were the same as in the second stage anaerobic fermentation. The results are shown in Table 3. The results in Table 3 were obtained about 30 days after fermenter operation.

Example 2

This embodiment relates to aerobic fermentation using the supernatant of the acid production tank of the two-step anaerobic fermentation tank.

Pig manure was treated using a two-stage anaerobic fermentation tank consisting of a polyethylene container (actual fermentation capacity) with a capacity of 1 ton of the structure as shown in FIGS. 1 and 2. The characteristics of the used manure are shown in Table 4. The volume ratio of the acid production tank and the methane production tank was 4:11. The operating conditions were that the residence time of the liquid substance was 15 days, the hydraulic residence time in the acid production tank was 4 days, and the hydraulic residence time in the methane production tank was 11 days. Swine manure was divided into a total of 53.3 L per day into an acid production tank, and about 45 L of supernatant was discharged from methane production per day. Some of the supernatant discharged was added to the aerobic fermentation tank along with the supernatant extracted from the acid production tank, and the input amount was 40L per day, which was divided into 8 cycles. In the acid production tank, the supernatant was transferred to the aerobic fermentation tank in a total of 13.3L per day. The characteristics of the supernatant, sludge and mixtures of the acid production baths are shown in Table 5. 3 shows the change of sludge mixing and mixing of the contents of the acid production tank. The temperature of the anaerobic fermentation tank was maintained at 39 ° C. Pig manure in the acid production tank and the methane production tank was mixed (stirred) by circulating methane gas produced during anaerobic fermentation using acid pipes installed inside the fermentation tank, and both the acid production tank and the methane production tank were intermittently sludge solidified. It was not enough. After stirring the separation of the supernatant and sludge layer, ie the solids took 20-30 minutes. The sludge was discharged out of the methane production tank over a short period of 2-3 minutes.

Conventional one-stage anaerobic fermentation experiments used fermenters of the same size and structure as the two-stage anaerobic fermentation, but did not install only diaphragms. The residence time was 15 days. Other conditions were the same as the two stage anaerobic fermentation.

The aerobic fermentation tank was operated in a bottom aeration manner using an 80L acrylic container. The aeration was continued and the air at 20 ° C. was aerated in an amount of 1 L per minute per liter of fermenter work. At this time, the residence time of the liquid substance (HRT) was 1 day and operated at room temperature (20 ℃). Under the same conditions as above, the fermentation conditions of anaerobic and aerobic were operated for 3 months in the present invention and conventional manner. The results are shown in Table 6.

Example 3

This embodiment relates to the sludge obtained by precipitating the effluent after the two-step anaerobic fermentation to be returned to the acid production tank for reuse.

Pig manure was treated using a two-stage anaerobic fermentation tank with a polyethylene container (actual fermentation capacity) of 1 ton capacity with the structure as shown in FIGS. 1 and 2. The characteristics of the used manure are shown in Table 1. The volume ratio of the acid production tank and the methane production tank was 4:11. The operating conditions were that the residence time of the liquid substance was 15 days, the hydraulic residence time in the acid production tank was 4 days, and the hydraulic residence time in the methane production tank was 11 days. Pig manure was divided into 8 groups of 53.3L / day into the acid production tank. And, the supernatant was discharged from the methane production tank 45L per day, which is about 85% of the pig manure input. The remainder was released as steam, methane and sludge. The temperature of the fermenter was maintained at 39 ° C. of mesophilic fermentation.

Mixing (stirring) of pig manure in the acid production tank and the methane production tank was performed by circulating methane gas produced during anaerobic fermentation using acid pipes installed inside the fermentation tank, and both the acid production tank and the methane production tank were intermittently sludge solidified. A short time of 2-3 minutes was carried out so as not to. After stirring it took 20-30 days for separation of the supernatant and sludge layer, ie the solids settling. The sludge was discharged out of the methane production tank over a short period of 2-3 minutes.

The supernatant discharged from the methane production tank was precipitated in the sedimentation tank to obtain sludge, and 5.3 L, corresponding to about 10% of the manure that was put into the acid production tank per day, was returned to the acid production tank once. Table 7 shows the results of treating pig manure by operating the fermenter for three months in the same way as above.

Example 4

This embodiment is an example showing the whole process until the pig manure discharged from the barn through the two-stage anaerobic fermentation process of the present invention until it is finally reused as recycled water or used as discharge or compost. 4 shows a flow chart of the process. The configuration of the process is described in more detail as follows.

(1) separator

Device for sorting coarse particles

(2) Anaerobic two-stage fermentation tank (acid-producing fermentation tank, methane production tank) stage 1: structure shown in Figure 1, Figure 2

Acid-producing fermenters: retention time (HRT) 4 days

Methane-generating fermenters: 11 days load rate (HRT)

-Warmer: The hot water circulation system (generated methane gas) is burned to obtain hot water and internal fermenter gas and hot water circulation method.

-Contents Mixer: Mix the contents by blowing the gas circulation system (pumped methane gas into the acid pipe installed in the lower part of the fermenter)

Methane gas storage device

-Desulfurization device: A device for removing hydrogen sulfide contained in methane

(3) anaerobic fermentation tank waste liquid sedimentation tank-2

-Primary sedimentation tank: Load rate (HRT) -0.15 days

Secondary settling tank: Load rate (HRT)-0.5 days

(4) 2 aerobic fermentation tanks

First fermentation: HRT-1 day

2nd aerobic fermentation: load rate (HRT) -2 days

(5) aerobic waste liquid sedimentation tank

Load rate (HRT) 1 day

(6) filtration tank

-Filtration tank: 1 day load rate (HRT)

(7) Other equipment: feeding device, conveying device, discharge device

The treatment process system of this example was manufactured on a pilot scale and automated to use in experiments. The structure of this system is the same as the above technique, and the size of the anaerobic fermentation tank (Acidogenic fermenter + Methanogenic fermenter, volume ratio Acoodogenic stage: Methanoge-nic stage = 4:11) is 800L. And other devices were fabricated and used at scale. The components of pig sludge used in this experiment are shown in Table 8, and the conditions of the experimental process are shown in Table 9. The experiment was conducted for 6 months. Table 10 shows the treatment efficiency of this process.

As can be seen from the above, the two-stage anaerobic fermentation tank of the present invention is extremely simple in structure and easy to operate, and the two-stage anaerobic fermentation of the present invention using such a fermentation tank is also easy to carry out, as well as the load and properties of the influent wastewater. Regardless, it maintains high fermentation stability and has excellent treatment efficiency.

Claims (25)

In the first step of fermentation of organic waste liquid in the first fermentation tank, the organic acid produced in the fermentation step, the organic waste liquid passed through the organic acid production fermentation step to the second fermentation tank methane production fermentation method comprising the step of anaerobic fermentation of organic waste liquid in the first fermentation tank, The transfer of the organic waste liquid to the second fermentation tank is a two-stage anaerobic fermentation method of organic waste liquid, characterized in that the sludge layer formed in the lower portion of the first fermentation tank through the sludge layer formed in the lower portion of the second fermentation tank. The method of claim 1, The first fermentation tank and the second fermentation tank is a two-step anaerobic fermentation method of organic waste liquid, characterized in that the operation is continuous. The method of claim 1, The second step anaerobic fermentation method of the organic waste liquid, characterized in that the slurry accumulated in the bottom in the second fermentation tank is discharged out. The method of claim 1, The ratio of the hydraulic retention time in the first and second fermentation tanks of the organic waste liquid is approximately 4:11. The method of claim 1, A two-step anaerobic fermentation method of organic waste liquid, characterized in that the sludge obtained by precipitating the organic waste liquid passed through the methane production fermentation step is returned to the first fermentation tank. The method according to any one of claims 1 to 5, The organic waste solution is a two-step anaerobic fermentation method of organic waste liquid, characterized in that the manure. The method of claim 6, Said manure is a human anaerobic two-step anaerobic fermentation method, characterized in that the human. The method of claim 6, The manure is a two-step anaerobic fermentation method of organic waste, characterized in that the livestock. The method of claim 8, The livestock manure is a two-step anaerobic fermentation method of organic waste, characterized in that the pig. Organic waste liquid is produced and fermented to the first fermentation tank, and the organic waste liquid which has undergone the organic acid production fermentation step is then transferred from the second fermentation tank formed at the bottom of the second fermentation tank to the methane production in the sludge layer formed at the bottom of the first fermentation tank. Consisting of the fermentation, the transfer of the organic waste liquid from the first fermentation tank to the second fermentation tank comprises a two-step anaerobic fermentation process consisting of the portion of the sludge layer of the first fermentation tank is formed. Anaerobic treatment method of organic waste liquid, characterized in that. The method of claim 10, The anaerobic treatment method of organic waste liquid characterized in that the slurry accumulated at the bottom in the second fermentation tank is discharged out. The method of claim 10, Anaerobic treatment method of organic waste liquid, characterized in that further comprising the step of aerobic fermentation of the organic waste liquid subjected to the two-stage anaerobic fermentation process in a third fermentation tank. The method of claim 11, A part of the supernatant of the first fermentation tank is supplied to the third fermentation tank. The method of claim 12, The supernatant of the third fermentation tank transferred to the third fermentation tank has a relationship of 1: 4-1: 8 in volume ratio with respect to the organic waste liquid which has undergone the two-step anaerobic fermentation process flowing into the third fermentation tank. Anaerobic treatment. The method according to claim 12, wherein The sum of the hydraulic retention times in the first and second fermentation tanks of the organic waste liquid is approximately 15 days, and the ratio is approximately 4:11. The method of claim 15, The organic waste solution is anaerobic treatment method of organic waste liquid, characterized in that the manure. The method of claim 16, The manure is anaerobic treatment method of an organic waste liquid, characterized in that the human. The method of claim 16, The manure is anaerobic treatment method of organic waste liquid, characterized in that the animal. The method of claim 18, The livestock manure is anaerobic treatment method of organic waste liquid, characterized in that the pig. A fermentation tank for fermenting manure; A diaphragm installed in the fermentation tank so as to separate and form an organic acid producing fermentation portion and a methane producing fermentation portion, and having a sludge distribution port for distributing sludge at a lower portion thereof; A sludge collection unit for collecting sludge on the bottom of the methane-producing fermentation unit of the fermentation tank; A two-stage anaerobic fermentation tank having a sludge outlet for discharging the sludge of the sludge collection unit to the outside. The method of claim 20, A two-stage anaerobic fermentation tank, characterized in that the bottom of the fermentation tank is inclined so as to be transported by sludge to the sludge collection unit. The method of claim 20, The diaphragm is a two-stage anaerobic fermentation tank characterized in that the gas distribution port for gas distribution between the organic acid generating fermentation unit and the methane production fermentation unit is installed at the top. The method of claim 20, A two-stage anaerobic fermentation tank, characterized in that the heating device is installed inside the fermenter to temperature the contents. The method of claim 23, wherein The heating device is a two-stage anaerobic fermentation tank, characterized in that the hot water circulation pipe or panel. The method of claim 20, The second stage anaerobic fermentation tank, characterized in that the diffuser is installed in the lower part of the fermentation tank for mixing the contents.