KR101273088B1 - Treatment system of food waste leachate - Google Patents

Abstract

PURPOSE: A treatment system for food waste leachate is provided to recycle waste and reduce secondary environmental problems by minimizing the generating amount of sludge. CONSTITUTION: A treatment system for food waste leachate includes a solid-liquid separator(20), a neutralizing unit(40), a thermally fusing unit(70), a boiler(80), a heat exchanger(60), a coagulation reactor(90), a pressurization floating bath(100), and an anaerobic digestion bath(120). The thermally fusing unit applies heat to neutralized water in order to thermally fuse sludge under the pH 6-7, the pressure of 18-22kg/cm^2, and the temperature of 180-220 deg. C. The boiler supplies a heat medium at 200-250 deg. C in order to supply heat required for the thermally fusing unit. The heat exchanger cools water from the thermally fusing unit. The coagulation reactor coagulates water from the heat exchanger. The pressurization floating bath floats and removes a coagulant containing oil parts. The anaerobic digestion bath methane-ferments water from the pressurization floating bath. [Reference numerals] (10) Effluent remain storage bath; (100) Pressurization floating bath; (110) Storage bath; (120) Anaerobic digestion bath; (130) Gas storage; (140) Excessive gas application device; (20) Solid-liquid separator; (30) Pulverizer; (40) Neutralizing unit; (50) Mixing unit; (60) Heat exchanger; (70) Thermally fusing unit; (80) Boiler; (90) Coagulation reactor; (AA) Rear part processing

Description

Treatment System of Food Waste Leachate

The present invention relates to a food waste desorption filtrate treatment system, and more particularly, to effectively remove oil and solids in the food waste desorption filtrate, and to minimize the amount of sludge while reducing the amount of chemical input, significantly reducing the operating cost and energy consumption. In addition, the present invention relates to a food waste desorption filtrate treatment system that can help to solve the energy shortage in the summer season by recycling and energyizing wastes and reducing secondary environmental pollution problems.

The desorption filtrate discharged during food waste dehydration is composed of water, suspended solids and oil. The oil is stably present in the aqueous layer in an emulsion state, and the suspended solids are dispersed in fine particles, so it is difficult to separate the oil and suspended solids from the desorption liquid in a conventional manner.

To date, various methods of treating food waste are known as follows.

First, it can be buried directly in the ground, but it is forbidden due to bad smell and groundwater pollution.

Secondly, sterilization at high temperature can be used as feed for animals, but this method is bad in odor, low in nutrient value as feed, low in demand, and low in metropolitan area due to high fuel cost and condensate treatment.

The third method is composting by mixing food waste with a deodorant, and this method is not only bad smell, but also the problem of poor housing due to salt and oil, salt accumulation of farmland, lack of spray farmland, etc. Low effectiveness at

Fourth, dehydration sludge is incinerated by solid-liquid separation, and delying filtrate is introduced into sewage treatment plant. This treatment method should solve the odor problem, increase the incinerator and sewage treatment plant, review the total phosphorus (TP) and total nitrogen (TN) treatment methods of the sewage treatment plant, and invest in additional facilities in the long term. do.

Next, the dehydration sludge is composted by solid-liquid separation and the desorption filtrate is treated separately. In the composting of dehydrated sludge, most of the salinity and oil are drained into the desorption filtrate, which can solve the problem of salt accumulation and process erosion, and the amount of dewatered sludge is reduced to 20-40%. It can reduce the number of complaints or odors. It is also very economical because it recycles waste. However, in the treatment of the tallying filtrate, it has been possible to dispose of it as marine dumping, but the prohibition of the dumping of the ocean is decided in the future, so the treatment is urgent.

If you look at the water quality of the food waste stripping filtrate, total solids (TS) concentration of 80,000 to 150,000 mg / ℓ, CODcr concentration of 100,000 to 250,000 mg / ℓ, BOD concentration of 50,000 to 100,000 mg / ℓ, total nitrogen ( TN) concentration is 2,000 ~ 4,000 mg / ℓ, salt concentration is 8,000 ~ 10,000 mg / ℓ, total phosphorus (TP) concentration is 600 ~ 800 mg / ℓ, oil concentration is 0.5 ~ 1.50,000 mg / ℓ. . In addition, acid fermentation occurs during the collection process is characterized by a very low pH concentration of 3.0 ~ 4.0. Since 500 to 2000 times the concentration of sewage is high, if the concentration is not reduced and neutralized in the pretreatment process, the treatment cost and the area are increased, and the treatment efficiency is lowered.

In addition, the food waste desorption filtrate contains a high concentration of solids, so it must be separated and dehydrated, but it does not react well with chemicals, and there is a lot of sludge generated by aggregation.

The sludge generated in such a large amount is composted without landfill due to groundwater contamination problems, or transferred to an incinerator for incineration. However, the sludge has high salinity, high water content, and high concentrations of animal and vegetable fats and oils, causing many problems in composting and incineration.

Therefore, it is urgently required to reduce the amount of sludge generated in the process of food waste removal filtrate in terms of economics or environmental protection.

The present invention has been made to solve the problems of the prior art as described above, the purpose is to effectively remove the oil and solids in the food waste desorption filtrate, to minimize the amount of sludge, while reducing the amount of chemical input, operating costs In addition to significantly reducing energy consumption, it is also to provide a food waste removal filtrate treatment system that can help to solve the energy shortage in the summer season by recycling and energyizing wastes and reducing secondary environmental pollution.

The technical problem of the present invention as described above is achieved by the following means.

(1) a heat solubilizing apparatus for solubilizing sludge by applying heat to the food waste detachment filtrate; A boiler for supplying heat required for the heat solubilizing device; A heat exchanger for exchanging heat between the high temperature treated water discharged from the heat solubilizer and the low temperature treated water flowing into the heat solubilizer; A pressurized floatation tank for floating and removing the aggregates containing oil to solids of the heat-solubilized treated water in the heat solubilization device; And an anaerobic digestion tank for methane fermenting the treated water discharged from the pressurized floatation tank.

(2) The method according to claim 1,

High-volume decontamination of the tally filtrate; And a neutralizing device for neutralizing the treated water separated by the solid-liquid separator.

(3) The method according to claim 1,

Thermal solubilization apparatus is a food waste desorption filtrate treatment system characterized in that the thermal solubilization at a pH of the neutral region.

(4) The method according to 1,

Thermal solubilizer is a food waste desorption filtrate treatment system, characterized in that the thermal solubilization at pH 6-7.

(5) The method according to claim 1,

Thermal solubilizer is a food waste desorption filtrate treatment system characterized in that the thermal solubilization is performed at a pressure of 18 ~ 22 kg / ㎠, temperature 180 ~ 200 ℃.

(6) The method according to 1,

The temperature of the heat medium supplied from the boiler is a food waste desorption filtrate treatment system, characterized in that 200 ~ 250 ℃.

(7) The method according to 1,

A food waste desorption filtrate treatment system, characterized in that a coagulation reaction tank is further installed between the thermal solubilizer and the pressure flotation tank to add an inorganic coagulant, a caustic soda, and a polymer.

(8) The method according to 1,

Food waste desorption filtrate treatment system, characterized in that the air pressure of 3 ~ 5 kg / ㎠ injecting the pressure flotation tank.

(9) The method according to 1,

Food waste desorption filtrate processing system, characterized in that the pulverizer is further installed to grind particles larger than 0.1mm in the solid-liquid separator.

According to the present invention as described above, not only effectively remove the oil and solids in the food waste desorption filtrate, but also reduce the amount of chemical input while reducing the amount of sludge, significantly reducing the operating cost and energy consumption, and also to waste resources Reduce secondary pollution problems.

1 is a block diagram of a food waste desorption filtrate treatment system according to the present invention.
2 is a block diagram of a heat solubilizer according to an embodiment of the present invention.
3 is a block diagram of an agglomeration reaction tank according to an embodiment of the present invention.

The present invention provides a heat solubilizing apparatus for solubilizing sludge by applying heat to a food waste detachment filtrate; A boiler for supplying heat required for the heat solubilizing device; A heat exchanger for exchanging heat between the high temperature treated water discharged from the heat solubilizer and the low temperature treated water flowing into the heat solubilizer; A pressurized floatation tank for floating and removing the aggregates containing oil to solids of the heat-solubilized treated water in the heat solubilization device; And an anaerobic digestion tank for methane fermenting the treated water discharged from the pressurized floatation tank.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the food waste removal filtrate treatment system according to the present invention.

1 is a block diagram of a food waste removal filtrate treatment system according to the present invention.

As shown in Figure 1, the desorption filtrate treatment system according to the present invention, the desorption filtrate storage tank 10, solid-liquid separator 20, grinder 30, neutralizing device 40, mixing device 50, heat exchanger 60, the heat solubilizer 70, the boiler 80, the coagulation reaction tank 90, the pressure flotation tank 100, the storage tank 110, and the anaerobic digestion tank 120.

The collected food waste is first separated into solids and a stripping filtrate, and then the stripping filtrate is transferred to the storage tank 10 and stored.

The desorption filtrate stored in the storage tank 10 is transferred to the solid-liquid separator 20 to separate solid matter (fine contaminants) of a predetermined size, for example, φ = 1 mm or more.

The solid-liquid separator 20 preferably consists of a cylindrical inner cylinder and an outer cylinder which prevents the filtered filtrate from scattering. Inside the inner cylinder is provided with a scraper for discharging the separated impurities, the inner cylinder is rotated at 200rpm, the scraper at 220rpm, and discharges the impurities by the rotation difference. The body of the inner cylinder is decorated with a perforated net of φ = 1 mm or less or a wedge wire of a gap of 1 mm or less.

Solid content separated from the solid-liquid separator 20 is preferably sent to the grinder 30 to be pulverized to less than φ = 1mm and then transported to the storage tank (10).

The grinder 30 is equipped with a propeller blade in the body that prevents the scattering of crushed contaminants, the rotational speed of the blade is adjusted to 1200 ~ 3600rpm according to the type of contaminants.

The treated water separated from the solid-liquid separator 20 (hereinafter, the wastewater discharged through each constituent step will be referred to as treated water) is usually neutralized with an acidic solution having a pH in the range of 3 to 5. It is sent to and neutralized.

The neutralizer 40 is installed in the reactor of the rectangular cylinder form of 90 ~ 120rpm stirrer, the input pump and the neutralizer storage tank for inputting the neutralizing agent is installed. Preferably, the pH of the treated water discharged from the neutralization device 40 is adjusted to a range of 6 to 7, and the treatment efficiency of the firstly desorption filtrate supplied within the range is increased to 50%. To this end, the neutralization device 40 may be equipped with a pH meter (not shown) for detecting and adjusting the amount of neutralizing agent.

The treated water discharged from the neutralizing device 40 is introduced into the mixing device 50 to induce complete mixing, thereby increasing the solubilization efficiency of the thermal solubilizing device 70 at the rear end.

The mixing device 50 is installed in the reactor in the form of a square cylinder 90 ~ 120rpm stirrer. In the present invention, the mixing device 50 may be omitted in some cases, and the neutralization device 40 may be directly connected to the heat exchanger 60.

The treated water discharged from the mixing device 50 flows into the heat exchanger 60. The heat exchanger 60 performs a non-contact heat exchange between the high temperature treated water discharged from the heat solubilizer 70 and the low temperature treated water flowing into the heat exchanger.

A flow meter and a pressure gauge are installed at the inlet of the treated water in the heat exchanger 60 to control the flow rate and the pressure, and a pressure gauge and an automatic valve are installed at the discharge part of the heat-treated cooled treated water (thermal solubilized water). .

The treated water, which is preliminarily heated in the heat exchanger 60, is introduced into the heat solubilizer 70 so that a thermal hydrolysis reaction can be effectively performed even though a relatively small heat source is supplied from the boiler 80.

 To this end, the boiler 80 is a heat medium boiler, which is composed of a body, a burner, a circulation pump, a heat medium expansion tank, a heat oil shut-off automatic valve, a communication, a storage tank for heating material, and a control system. Preferably the burner of the boiler 80 uses a combined burner that can use the biogas and propane gas produced in the system of the present invention. Thermal medium supply temperature is 200 ~ 250 ℃, the automatic valve is operated according to the temperature of the heat solubilization device, the supply pressure is preferably set to 1 ~ 3kg / ㎠.

As illustrated in FIG. 2, the heat solubilizer 70 includes an inner tube 71, an outer tube 72, and a swirl flow guide unit 73.

 The inner tube 71 has a treatment water inlet 71a at one end and a treatment water outlet 71b at the other end. The inner tube 71 is the treated water is introduced through the treated water inlet 71a, the treated water is thermally hydrolyzed and discharged to the outside through the treated water outlet 71b, the treated water of the treated water can be thermally hydrolyzed It serves to provide a reaction space.

 The exterior 72 is formed with an inlet 72a through which a heat medium supplied from a boiler 80 is input at one end thereof, and a heat medium is introduced therein, and is introduced through a heat medium outlet 72b formed at one side of the other end. The heat medium is discharged to the outside and refluxed to the boiler 80 for circulation.

Here, the appearance 72 serves to promote thermal hydrolysis of the treated water by promoting the flow of the treated water by heating the treated water introduced into the inner tube 71 by heating the inner tube 71 by the heat medium introduced therein. do.

The swirl flow guide portion 73 is configured to include a support 73a installed in the inner tube 71 and a swirl flow guide blade 73b spirally formed on the outer circumferential surface of the support 73a. By 73b, the inner space of the inner tube 71 is partitioned into a plurality of spaces, thereby serving to rotate the treated water. The swirl flow guide blade (73b) serves to guide the direction of movement of the treated water so that the treated water flowing into the inner tube (71) can pivot.

Due to the structure as described above, the heat exchange efficiency between the treated water and the heat medium, that is, the heat transfer efficiency transferred from the heat medium to the treated water is very large, so that the stirring of the treated water is performed smoothly without a separate stirring facility, and the reactant such as the treated water. Precipitation or deposition can be prevented and the reaction efficiency can be improved.

Preferably, the heat solubilizer 70 performs heat solubilization at a pressure of 18 ~ 22 kg / ㎠, temperature 180 ~ 200 ℃, for this purpose the temperature of the heat medium supplied from the boiler 80 is 200 ~ 250 ℃ It is good. Under such conditions, solubilization of solids is perfectly performed with only a relatively small heat source without additionally adding a reaction catalyst and an oxidant into the heat solubilizer 70.

To this end, the heat solubilizer 70 may be further equipped with a sensor for sensing the flow rate, temperature, pressure, automatic valve for pressure regulation, and control means for controlling them.

The treated water discharged from the heat solubilizer 70 is supplied to the coagulation reaction tank 90 via the heat exchanger 60. The flocculation reactor 90 is preferably equipped with a stirring means (not shown) and a pH meter (not shown) for sensing and adjusting the flocculant amount to assist the flocculation reaction.

The agglomeration reaction vessel 90 is for agglomeration of various particles including oil, fine solids, and the like contained in the treated water. For this purpose, an inorganic coagulant, caustic soda, and a polymer are introduced as needed through the coagulant inlet. At this time, the amount of flocculant can be detected and controlled using a pH meter (not shown).

In the present invention, the agglomeration reaction vessel 90 is preferably in the form of a pipe reactor as shown in FIG. 3, by stacking pipes 90a in multiple stages, such as the discharge aperture of a feed pump (not shown) in front, and stirring efficiency and It can increase the space utilization.

At this time, the multi-stage pipe (90a) is stacked up and the pipes of the upper and lower ends are connected to the elbow (90b) consisting of both ends (90b ₁ , 90b ₂ ) of the upper and lower pipes, then the front end 91 is the inlet pump, the rear end 92 is pressurized Connect with the floating tank (100). In this case, preferably, an inlet (not shown) is installed at the front of the reactor so that the organic coagulant may be added. The length of the pipe reactor is preferably installed so that the residence time is 25 ~ 60sec.

As such, when implementing the coagulation reaction tank 90 in a multi-stage pipe, a separate stirrer is not required, thereby reducing equipment and operating costs, and a general coagulation reaction requires a neutralizer input device and an inorganic coagulant input device. In (90), it is possible to exhibit high solid-liquid separation efficiency in the pressurization tank 100 at the rear stage even without these devices due to the characteristics of the process.

Oil in the aggregate formed in the agglomeration reaction vessel 90 contains a large amount of fat component is light weight because the precipitation is not well made solid separation is not easy, in the present invention, the pressure flotation tank (100) in the rear end of the agglomeration reaction tank (90) Install).

Pressurized floatation tank (100) to remove the remaining suspended solids to remove the obstructive elements of the anaerobic digestion tank 120 of the rear end, and improve the extinguishing efficiency. Pressurized floatation tank 100 is installed in the rectangular rectangular cylinder of the upper scraper to remove the scum to discharge the suspended solids to the rear end of the pressurized flotation. A high pressure pressurization pump is installed at the bottom of the rear end of the pressurized floatation tank 100 to continuously circulate the treated water to the front end through a pipe reactor type distribution device, and the high pressure air in the middle of the rear end of the pressure pump and the distribution device (preferably 3 kg / ㎠ or more) is injected using a compressor or the like to increase the floating efficiency. In the embodiment of the present invention, the linear speed of the scraper is 1 ~ 3m / min, the pressure of the pressure pump is 3 ~ 5 kg / ㎠, the circulation rate of the pressure pump is operated at 50 to 100% of the inflow flow rate, It is recommended to operate the area load at 4 ~ 5㎥ / ㎡ ㅇ hr.

The treated water discharged from the pressurized floatation tank 100 is in a state in which solid content including oil is almost removed, and is once stored in the storage tank 110 and then transferred to the anaerobic digestion tank 120 at the rear end.

The anaerobic digester 120 removes organic matter present in the treated water using methane fermentation. Methane fermentation bacteria are cultured in the anaerobic digester 120, the organic matter in the treated water is decomposed by these bacteria, the methane gas produced at this time is discharged to the outside.

The anaerobic digester 120 is installed in the bottom of the barrel in the form of a square column inlet distribution device is installed in the upper GSS device for gas-liquid separation. At this time, the inflow water is introduced using a distribution device at the bottom, and a return pump may be installed to increase the activity of anaerobic microorganisms. The upper GSS unit installs rectangular GAS-HOLDER to prevent methane gas from scattering and install WAIR to discharge treated water.

Preferably, the methane gas discharged from the anaerobic digestion tank 120 is stored in the gas storage tank 130 to procure the energy required by the process itself, and the remaining gas (approximately 50 to 60%) is a variety of surplus gas utilization equipment. Through 140 to generate electricity, or to use as a gas for fuel.

The gas storage tank 130 allows the methane gas generated in the dome form to be used according to the purpose of use through dehumidification, desulfurization, and storage. The methane gas collected in the anaerobic digester 120 is temporarily stored in the gas storage tank 130 through a dehumidification apparatus and a desulfurization apparatus and then transferred to a compression storage furnace using a gas compressor to be used according to the purpose of use. At this time, some of the gas is used as a fuel of the heat medium boiler 80 of the heat solubilization device, and the remaining surplus gas may be installed in a generator to produce electricity or may be sold to a gas company by installing a purifier. Preferably, the dome-type and compressed storage tanks are installed at a size of HRT = 6-8 hr, and a generator or methane gas purifier is installed at a capacity of 1-2 hrs of output.

The treated water discharged from the anaerobic digester 120 is treated by a post-treatment step of the subsequent process. In describing the apparatus of the present invention as described above, a pump may be mounted as many as necessary in a necessary place for the transfer of the treated water between the apparatuses, and this configuration is obvious to those skilled in the art, and detailed description thereof will be omitted.

When the system according to the present invention is used as described above, the oxidation and hydrolysis efficiency is high without maximizing heat exchange efficiency, so that the fine solids (cold matter) and sludge contained in the food waste desorption filtrate are not deposited in the heat solubilizing device constituting the system. In addition to effectively removing the oil and solids in the treated water finally discharged, the organic matter in the treated water can be completely removed by anaerobic fermentation.

Hereinafter, the present invention will be described in more detail with reference to the following examples and comparative examples. However, this is to facilitate an easier understanding of the present invention, and is not intended to limit the present invention through these.

Example 1

Oil and solids in 20 tons of treated water finally discharged as a result of treating food waste using the system shown in FIG. 1 (see the operating conditions in Tables 1 to 2 below) are initially desorption filtrate (desorption discharged from the solid-liquid separator). In addition to the effective removal of up to 75% compared to the filtrate, organic matter in the treated water was completely removed by methane gas by anaerobic fermentation (Table 3).

Heat exchanger operating condition Inflow temperature
(℃) Discharge temperature
(℃) Inlet pressure
(kg / ㎠) Outflow pressure
(kg / ㎠) Residence time
(min) Tally Filtrate 3 to 20 120-132 22 21 30 to 40 Heat-soluble water 180-200 45-55 20 19 40-60

The pressure change is due to the pressure loss due to the passage length.

Thermal solubilizer operating condition Inflow temperature
(℃) Discharge temperature
(℃) Inlet pressure
(kg / ㎠) Outflow pressure
(kg / ㎠) Residence time
(min) Heat solubilizer 120-132 180-200 21 20 90-120

Processing result Oil Solids Organic matter Initial Tally Filtrate 100 100 100 Final treatment 0 25 20

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. It can be understood that

10: Tali Filtrate Storage Tank
20: solid-liquid separator
30: grinder
40: neutralizing device
50: mixer
60: heat exchanger
70: heat solubilizer
80: boiler
90: flocculation reactor
100: pressurization
110: reservoir
120: anaerobic digester
130: gas reservoir
140: surplus gas equipment

Claims (9)

Solid-liquid separator for solid-liquid separation of food waste stripping filtrate; A neutralizing device for neutralizing the treated water separated by the solid-liquid separator; A heat solubilizer for heat solubilizing the sludge at a pH of 6 to 7, a pressure of 18 to 22 kg / cm 2, and a temperature of 180 to 200 ° C. by applying heat to the neutralized treated water; Boiler for supplying a heat medium of 200 ~ 250 ℃ to supply the heat required for the heat solubilization device; A heat exchanger for cooling the treated water discharged from the heat solubilizer; An agglomeration reaction tank for coagulating the treated water cooled in the heat exchanger; A pressurized floatation tank for introducing air of a pressure of 3 to 5 kg / cm 2 to float and remove flocculates including the oil of the treated water flocculated by the flocculation reaction tank; And an anaerobic digestion tank for methane fermenting the treated water discharged from the pressurized floatation tank. delete delete delete delete delete delete delete The method of claim 1,
Food waste desorption filtrate processing system, characterized in that the pulverizer is further installed to grind particles larger than 0.1mm in the solid-liquid separator.

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