KR101494177B1 - Food waste leachate preprocessor for improving landfill gas generation rate - Google Patents

Abstract

The present invention relates to a food waste leachate preprocessing apparatus for improving a landfill gas generation amount, the apparatus including a dehydrator that dehydrates food waste in particular for separate discharge of dehydrated cake and food waste leachate; a screen tank that removes the foreign matter contained in the food waste leachate discharged from the dehydrator; a food waste leachate storage tank that stores the food waste leachate passing through the screen tank; a preprocessing tank that has a carrier therein to which an acid fermentation strain is fixed and is supplied with the food waste leachate, fed by a first pump from the food waste leachate storage tank, in a lower portion for hydrolysis so that the an organic material can be discharged upward with the particle size and viscosity decreased; and landfill piping that is disposed in a landfill and injects the food waste leachate preprocessed by the preprocessing tank into the landfill by using a second pump. According to the present invention, the organic acid of the food waste leachate is increased through the preprocessing tank by using the food waste leachate alone, thereby allowing the penetration in the landfill to be smooth. Accordingly, LFG production speed can be reduced and an LFG generation amount can be increased.

Description

TECHNICAL FIELD [0001] The present invention relates to a waste water pre-treatment apparatus for improving the amount of landfill gas generated,

The present invention relates to a waste water treatment apparatus for improving the amount of landfill gas generated, and more particularly, to a waste water treatment apparatus for improving the amount of landfill gas discharged from a landfill (waste water wastewater treatment plant) through a pretreatment tank (biological acid fermentation) The present invention relates to a waste water pre-treatment apparatus for improving the amount of LFG produced by shortening the production rate of LFG by enhancing smooth permeation and improvement of organic amount.

Generally, the main components of landfill gas generated from landfill are methane and carbon dioxide, and a small amount of other minor components are contained. Trace elements in these landfills are harmful to the environment, such as generating odors. Methane and carbon dioxide are greenhouse gases that cause global warming.

Therefore, the landfill gas generated from the landfill should be appropriately treated by a method such as high temperature combustion, but the methane gas, which accounts for about half of the landfill gas, is combustible, so if properly collected and utilized, it can be used as a fuel to replace the fossil fuel The sex is very high.

BACKGROUND ART Conventionally, many technologies for collecting methane gas from landfill gas (LFG), which are naturally occurring in a landfill, are utilized as energy resources.

However, there is no research or technology development for methane gas production, and there is almost no research other than leachate recycling. Especially, since the amount of LFG is rapidly decreased after the introduction of food waste into the landfill site, it is economically and technically limited to use the waste water pretreatment device for improving the LFG generation as energy resources.

Typical anaerobic methanogenic reactions consist of hydrolysis, acidogenesis, and methanogenesis. In the case of solid wastes, the hydrolysis step acts as a rate-limiting step in the overall process. In particular, in the anaerobic methanogenic reaction in the landfill, the rate of hydrolysis is very slow. Therefore, methane gas starts to be produced in at least 6 months after the start of landfilling. Therefore, it takes an additional period of time to produce LFG using a conventional household waste landfill.

Also, as shown in FIG. 1, the production amount of LFG and the methane content tend to decrease with elapse of time in accordance with the decrease of the amount of decomposable organic matter and the change of conditions inside the landfill.

In order to solve such a problem, Korean Patent Registration No. 10-0933237 (biogas production device through a landfill anaerobic combined bioreactor) was filed and registered.

The biogas production unit through the landfill anaerobic bioreactor is operated by stirring the organic wastes such as the industrial waste liquid, the food waste liquid, the livestock wastewater and the leachate, maintaining the reaction temperature at 25 to 45 ° C, A combined fermentation effluent for causing volatile organic compounds such as acetic acid to be generated by hydrolysis by a fermenting microorganism and producing volatile organic compounds and odorous gases generated during acid fermentation; The acid fermentation broth is supplied to the combined acid fermentation broth, and the supplied acid fermentation broth is converted into methane gas together with the household waste already buried through the anaerobic methanogenic reaction. The methane gas and the odor generated by the anaerobic reaction A bioreactor for collecting gas; The combined fermentation effluent and the bioreactor are fed to the bioreactor, and the amount of leachate generated and the amount of generated gas generated in the bioreactor are monitored to reduce the amount of generated leachate and increase the amount of generated gas. An injection quantity adjusting unit for controlling the supply amount of the acid fermentation liquid; The odor gas and the volatile organic compound generated from the combined acid-decomposable enzyme are incinerated, and the odor gas and methane gas generated from the bioreactor are inhaled, dehumidified, filtered, and supplied to the use facility And the other gases are incinerated; And a leachate recirculation unit connected to the merged aerosols and bioreactors to collect leachate generated due to rainwater and reaction products at the bottom of the bioreactor and to supply the collected leachate to the bottle sowing fermentation unit.

However, the conventional biogas production unit using the bioreactor of the landfill anaerobic bioreactor has been improved and used to improve the amount of LFG, but there is a limit in the amount of generated biogas. The technology of injecting organic wastewater without pretreatment of waste landfill showed a slight increase in the amount of generated but the problem of secondary pollution caused by the clogging of the injection well occurred.

Korean Patent No. 10-0933237 Korean Patent Laid-Open No. 10-2007-0047731 Korean Patent No. 10-1201223

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method of reducing the production rate of LFG by increasing the organic acid in the wastewater through the pretreatment tank, And to provide a waste water treatment apparatus for improving the amount of landfill gas generated to increase the amount of generated waste water.

According to an aspect of the present invention,

A dehydrator for dehydrating the food waste and separating the dehydrated cake and the wastewater from the dehydrated cake; A screen tank for removing foreign matter contained in the waste water discharged from the dehydrator; A negative wastewater storage tank for storing negative wastewater passing through the screen tank; A pre-treatment for reducing the particle size and viscosity of the organic material and discharging the wastewater to the upper part by injecting the wastewater discharged from the wastewater storage tank by the first pump, article; And a landfill pipeline which is installed inside the landfill and injects the waste wastewater pretreated from the pre-treatment tank into the landfill by the second pump.

The waste water pretreatment apparatus for improving the buried gas generation amount may further include a pretreatment waste water storage tank installed between the pretreatment tank and the landfill pipe for storing pretreated waste water discharged from the pretreatment tank by the third pump .

Here, the negative wastewater pretreatment apparatus for improving the buried gas generation amount may further include: a COD detector for detecting the COD concentration of the negative wastewater supplied from the negative wastewater storage tank to the pretreatment tank; And a controller for adjusting the operation speed of the first pump according to a predetermined value according to the COD concentration of the waste water detected from the COD detector.

Here, the controller controls the operation speed (L / day) of the first pump by the following equation.

V: pre-treatment tank volume (L), and C: COD concentration (g / L)).

Herein, the waste water in the pretreatment tank stays within 5 days.

Here, the landfill pipe is provided with a plurality of discharge holes on the lower end outer side, and is installed perpendicular to the landfill.

According to the present invention configured as described above, the waste water pre-treatment apparatus for improving the amount of the generated landfill gas can increase the organic acid of the waste wastewater through the pretreatment tank by using the waste water alone, The speed can be shortened and the amount of generated LFG can be increased.

1 is a graph showing the amount of landfill gas production over time in a general landfill.
FIG. 2 is a block diagram showing the construction of a waste water treatment apparatus for improving the buried gas generation amount according to the present invention.
FIG. 3 is a graph showing the rate of methane production according to whether or not the pretreatment tank is applied to the wastewater through the negative wastewater pretreatment apparatus for improving the buried gas generation amount according to the present invention.
FIG. 4 is a graph showing the total organic acid production amount with or without the application of the pretreatment process to the wastewater through the waste wastewater pretreatment apparatus for improving the buried gas generation amount according to the present invention.
FIG. 5 is a graph showing differences in viscosity depending on whether or not the pretreatment process is applied to the wastewater through the negative wastewater pretreatment apparatus for improving the buried gas generation amount according to the present invention.
FIG. 6 is a graph showing the difference in estimated landfill gas generation amount depending on whether or not the negative wastewater pretreatment apparatus for improving the buried gas generation amount according to the present invention is applied.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the construction of a waste water treatment apparatus for improving the buried gas generation amount according to the present invention will be described in detail with reference to the accompanying drawings.

In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and these may be changed according to the intention of the user, the operator, or the like. Therefore, the definition should be based on the contents throughout this specification.

FIG. 2 is a block diagram showing the construction of a waste water treatment apparatus for improving the buried gas generation amount according to the present invention.

2, the waste water pretreatment apparatus 100 for improving the buried gas generation amount according to the present invention includes a dehydrator 110, a screen tank 120, a waste water storage tank 130, a COD detector 140 A pretreatment waste water storage tank 160, a landfill piping 170 and a controller 180. The pretreatment waste water storage tank 160 is connected to the pretreatment /

First, the dehydrator 110 dehydrates the food waste as a normal structure, separates the dehydrated cake and the deionized water, and discharges the dehydrated cake.

The screen tank 120 removes food waste and foreign matter contained in the waste water discharged from the dehydrator 110 by a predetermined amount or more.

In addition, the negative waste water storage tank 130 temporarily stores negative waste water that has passed through the screen tank 120.

The COD detector 140 detects a COD (chemical oxygen demand) concentration of the negative wastewater discharged from the negative wastewater storage tank 130 and transmits the measured value to the controller 180 to be described later.

The preprocessing tank 150 is formed in a cylindrical shape and has a net-shaped carrier 151 therein. The acidic fermentation broth is immobilized on the carrier 151 and the first pump P1 is discharged from the waste water storage tank 130, And the hydrolysis is performed to reduce the particle size and the viscosity of the organic material and to discharge the water to the upper part. In this case, it is preferable that the pre-treatment tank 150 stays within 5 days. Here, it is preferable that the first pump (P1) is applied with an inverter pump whose operation speed is variable under the control of the controller (180).

The pretreatment waste water storage tank 160 stores the pretreated waste water discharged from the pretreatment tank 150 by the third pump P3.

The landfill piping 170 is installed inside the landfill 1 and injects the waste water that has been pretreated from the pretreatment tank 150 into the landfill 1 by the second pump P2. Here, it is preferable that the landfill piping 170 is provided with a plurality of discharge holes 171 on the lower end outer side and is installed perpendicularly to the landfill 1.

The controller 180 adjusts the operation speed of the first pump P1 according to a predetermined value according to the COD concentration of the wastewater detected by the COD detector 140. Here, the controller 180 controls the operation speed (L / day) of the first pump P1 by the following expression (1).

V: pre-treatment tank volume (L), and C: COD concentration (g / L)).

Hereinafter, the operation of the waste water pretreatment apparatus for improving the buried gas generation amount according to the present invention will be described in detail with reference to the accompanying drawings.

First, when the food waste is put into the dehydrator 110, the dehydrator 110 dehydrates the dehydrated cake, separates the dehydrated cake and the wastewater, and discharges them. At this time, the food waste is stored in a separate storage facility installed at a nearby location, or the food waste treatment facility and the landfill are installed at the same place, and the waste water pre-treatment apparatus 100 for improving the buried gas generation amount according to the present invention is installed .

When the waste water is discharged from the dehydrator 110, food waste and foreign substances having a predetermined size or larger are removed through the screen tank 120, and then the waste water is stored in the waste water storage tank 130.

Subsequently, the negative wastewater stored in the negative wastewater storage tank 130 is supplied to the pretreatment tank 150. The controller 180 calculates the first CO concentration by the COD concentration of the negative wastewater detected from the COD detector 140 Adjust the operation speed of the pump (P1).

Meanwhile, since the activated acid fermentation strains are immobilized on the carrier 151, the negative wastewater introduced into the pretreatment tank 150 is screened and hydrolyzed by the immobilized acid fermentation strains to reduce the particle size and viscosity of the wastewater Thereby increasing the amount of landfill gas generated in the landfill.

More specifically, the organic matter having a large molecular weight in the waste water is fixed from the lower part of the pretreatment tank 150 due to the screen function of the carrier 151, and the substances having a relatively small molecular weight are immobilized on the acid fermentation strain And then passes through the hydrolysis treatment.

The organics having a large molecular weight fixed to the lower end of the pretreatment tank 150 by the carrier 151 are subjected to hydrolysis treatment with an activated acid fermentation strain and after the particle size and viscosity of the organic substances are reduced, . As a result, the substances having relatively low molecular weights are discharged relatively earlier than the substances having a large molecular weight after the hydrolysis, and the substances having a high molecular weight relatively remain in the pre-treatment tank 150 for a long time. ) To be discharged to the outside, thereby exhibiting the pre-treatment efficiency of the stable waste water.

Then, the pre-treated negative wastewater is stored in the pre-treatment negative wastewater storage tank 160 and is injected into the landfill 1 through the landfill piping 170. At this time, the time to be injected into the landfill 1 through the landfill piping 170 may be controlled according to the control of the controller 180.

Meanwhile, an experiment of a waste water treatment apparatus for improving the amount of burnt gas generated according to the present invention has shown the following effects.

FIG. 3 is a graph showing the rate of methane production according to whether or not the pretreatment tank is applied to the wastewater through the negative wastewater pretreatment apparatus for improving the buried gas generation amount according to the present invention.

Methane production in the methane production tank was about 7 days after the injection. However, it was confirmed that the methane production started after 1 day from the input of the pretreated waste water into the methane production tank.

This is because the hydrolysis process known as the rate-limiting process in the methane production process is carried out by the pretreatment process, so that the molecular weight of the wastewater is monomolecular such as acetic acid and is easily converted to the substrate availability of methane production strain.

The methane production rate up to 20 days is 0.994㎥ / ㎥-reactor as a result of pre-treated wastewater. As a result, it is 0.597㎥ / ㎥-reactor. It is confirmed that methane production is about 1.6 times higher.

FIG. 4 is a graph showing the total organic acid production amount with or without the application of the pretreatment process to the wastewater through the waste wastewater pretreatment apparatus for improving the buried gas generation amount according to the present invention.

The total organic acid concentration of the pretreated wastewater was 23,175 ± 1,802 mg / L, which was about 2.7 times higher than that of the raw organic wastewater (8,603 ± 506 mg / L).

FIG. 5 is a graph showing differences in viscosity depending on whether or not the pretreatment process is applied to the wastewater through the negative wastewater pretreatment apparatus for improving the buried gas generation amount according to the present invention.

The viscosity refers to the internal friction or resistance generated when the fluid flows. The lower the viscosity, the more smooth operation can be achieved when the waste water is injected into the landfill. The viscosity value of the raw wastewater was 30.6 ± 3.5 cp, whereas the pretreated wastewater (after 7 days of acid fermentation) was 15.6 ± 2.7 cp. This means that pre - treated waste water is applied smoothly to the landfill.

FIG. 6 is a graph showing the difference in estimated landfill gas generation amount depending on whether or not the negative wastewater pretreatment apparatus for improving the buried gas generation amount according to the present invention is applied.

As shown in FIG. 1, the amount of decomposable organic matter is usually reduced, and the amount of organic waste to be produced is reduced. However, since the waste water treatment apparatus according to the present invention is applied, It will be possible to maintain the amount of increase continuously over time.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is to be understood, however, that the invention is not to be limited to the specific forms thereof, which are to be considered as being limited to the specific embodiments, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. .

1: Landfill 110: Dehydrator
120: Screen group 130: Waste water storage tank
140: COD detector 150: Pretreatment tank
160: pretreatment waste water storage tank 170: landfill piping
180: controller

Claims (6)

A dehydrator for dehydrating the food waste and separating the dehydrated cake and the wastewater from the dehydrated cake;
A screen tank for removing foreign matter contained in the waste water discharged from the dehydrator;
A negative wastewater storage tank for storing negative wastewater passing through the screen tank;
And an acid fermentation broth is immobilized on the support, and the wastewater discharged from the wastewater storage tank by the first pump is injected into the lower portion and hydrolyzed to reduce the particle size and viscosity of the organic matter, A preprocessing tank for discharging;
A landfill pipeline installed in the landfill and injecting waste water, which has been pretreated from the pretreatment tank, into the landfill by a second pump;
A pretreatment waste water storage tank installed between the pretreatment tank and the landfill piping to store pretreated waste water discharged from the pretreatment tank by a third pump;
A COD detector for detecting the concentration of COD in the waste water from the waste water storage tank to the pretreatment tank; And
And a controller for controlling the operation speed of the first pump according to a predetermined value according to COD concentration of the waste water detected from the COD detector. delete delete The method according to claim 1,
The controller comprising:
Wherein the operation speed (L / day) of the first pump is controlled by the following equation.

V: pre-treatment tank volume (L), and C: COD concentration (g / L)). The method according to claim 1,
The pre-
And the negative wastewater stays within 5 days. The method according to claim 1,
The landfill piping may comprise:
And a plurality of discharge holes are provided on a lower outer surface of the bottom plate and vertically installed on the landfill.

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