KR100949149B1 - Food Degreasing Solution - Google Patents

Abstract

PURPOSE: A processing method of food waste leachate is provided to maximize separation efficiency of solids and oil recovery rates by installing a floating tank for oil separation and a floating separation tank for solid-liquid separation. CONSTITUTION: A processing method of food waste leachate includes the following: separating oil included in food waste leachate which is pre-processed with microbubbles dissolved in pressurized and pressed water; storing separated oil; separating the oil and water by heating the stored oil in an oil storage tank(50); adjusting pH of the food waste on which oil is removed; producing floc by rapidly and slowly coagulating the food waste leachate; separating the produced floc; and circulating the processed water on each step.

Description

Food Desorption Method {omitted}

The present invention relates to a food desorption solution for treating 'food desorption liquid', which is a high concentration of organic waste liquid discharged from the 'remaining food resource recycling process', and more specifically, a wound for separation of oil and water for separating oil contained in the food desorption liquid. The present invention relates to a food desorption liquid treatment apparatus and method for maximizing oil recovery and solids separation efficiency by separately separating a separation tank and a floating separation tank for separation of solids for separating organic solids.

In general, 'food desorption liquid' refers to a high concentration of organic waste liquid discharged from the remaining food recycling process. Food desorption liquids contain more than 85% water, contain easily decaying organic matter, and are malignant waste fluids with a solids content (SS) of more than 100,000 ppm.

Food desorption liquids are not very different from the characteristics of food waste and vary greatly depending on the characteristics of the collection area, the characteristics of the foods eaten and the local food culture, but in general, they contain a lot of salts in consideration of the dietary habits of Korea. BOD, COD, SS, TN, TP, etc. were found to be very high, especially high organic acid concentration and low pH.

Food desorption liquids are prohibited from landfilling. Local governments also ban direct landfilling of food waste. Currently, food desorption liquids are disposed of at sea or under sewage treatment at 92% water content. However, dumping at sea is expected to be totally banned in 2013 under the London Convention, and there are concerns that complaints may arise due to the adverse effects of the treatment facilities and odors when the wastewater is treated at high concentrations.

Accordingly, in recent years, the amount of organic matter is minimized before the food desorption solution is immediately discarded or brought into the sewage treatment plant, and biogas is produced using an anaerobic digestion process or the food desorption solution is introduced into the sewage treatment plant.

Figure 1 shows an example of a conventional food leaving solution. As shown, the conventional food desorption liquid treatment apparatus is composed of a primary drum screen, a sedimentation tank, and a floating separation tank (1), a flocculation reaction tank (2) and a secondary drum screen tank (3) sequentially.

Therefore, the food desorption liquid is removed from the large coarse coarse matter, heavy sediment and oil through the primary drum screen, sedimentation tank and flotation tank (1). And the secondary drum screen (3) finally separates the solid aggregated in the reaction agglomeration tank (2).

And the oil separated in the floating separation tank (1) is stored in the oil storage tank (5), the sludge treated in the secondary drum screen (3) is introduced into the composting process through a dehydrator, the solid-liquid separated treatment water is discharged tank Discharged via In other words, the processed food desorption water, which has reduced the pollution concentration through the oil recovery and the solids removal process, flows into the sewage treatment plant and is linked.

In this way, the conventional food desorption liquid treatment apparatus is to separate the oil together with the solids in one floating separation tank (1). And the oil separated from the flotation tank (1) is stored in the oil storage tank (4). In addition, the reaction agglomeration tank 2 is installed in front of the secondary drum screen 3 to perform solid-liquid separation in the secondary drum screen 3.

However, the food desorption solution flowing into the flotation tank 1 contains a large amount of solids (SS), and thus it is not easy to recover the water. In other words, microbubbles should be attached to the surface of the oil attached to the SS or emulsified to float on the surface of the water, but the separation of the oil with high SS content does not occur easily because the microbubbles are not easily generated and the oil is not easily separated from the solids. not.

In addition, the separated oil forms a layer on the surface of water, but the conventional flotation tank 1 has a problem of degrading the quality of oil recovered by mixing the water layer and the oil layer during oil recovery by skimmer operation.

In addition, when the flocculant is administered to the food desorption liquid having a large amount of oil, a large floc is hardly formed because the oil surrounds the fine solid. Therefore, as in the prior art, when a flocculant is added to a food desorption liquid in which oil is not completely separated and solid-liquid separation is carried out through the second drum screen 3 after the flocculation reaction, the flocculation efficiency is less than 1 mm when the drum screen flows in an unsuitable state. SS is discharged into the treated water has a problem that the treated water quality is poor and the sludge properties are also poor.

Thus, the conventional food desorption liquid treatment apparatus has a low sludge generation efficiency due to low liquid-liquid separation efficiency and poor treatment water quality, and the sludge property contains a lot of water. In addition, a sufficient flocculation reaction facility and a solid-liquid separation facility are required to process the food desorption solution generated in a day, but the conventional treatment apparatus has a low basic capacity and a short residence time, thereby reducing treatment efficiency. For example, in the conventional flocculation tank, the residence time of each tank is only about 5 minutes. On the contrary, it is inevitable to expand the processing equipment in order to make the residence time sufficient, but in this case, additional investment cost is required.

In addition, the secondary drum screen (3) has a high water content of the sludge generated by the inflow of a large amount of food desorption solution in which the aggregation reaction is not properly performed. In addition, due to the excessive content of oil and organic matter in the final treated water, the sewage treatment plant linked treatment adversely affects the stable operation of the sewage treatment plant.

As described above, since the conventional food desorption solution processing apparatus has a limitation in processing food desorption liquids containing a high concentration of organic matter, oil and organic acids, the development of a new food desorption solution processing system is urgently required.

The present invention is to solve the problems of the prior art, the main object of the present invention is to improve the treatment efficiency of the food desorption solution to improve the quality of the treated water, to reduce the water content of the sludge generated, and to improve the efficiency of oil recovery It is to provide an apparatus and method for treating food desorption liquid.

Another object of the present invention is to separate and install the flotation separation tank for oil and water separation to separate the oil contained in the food desorption liquid, and the solids separation separation tank for separating the organic solids, and in the flotation separation tank for solid-liquid separation Part of the discharged treated water is pressurized with high pressure air to generate pressurized water in which microbubbles are dissolved, and it is circulated and supplied to the solid-liquid separation flotation and the oil-water separation flotation tank to dilute the concentration of the desorbent in the flotation separation tank for oil-water separation. And, to maximize the separation of oil, the flocculant is injected into the desorbent from which the oil is removed, and the flocculation reaction to provide a food desorption liquid treatment apparatus and method that can maximize the solid-liquid separation efficiency by solid-liquid separation in the flotation separation tank for solid-liquid separation. .

Another object of the present invention is to effectively remove the solids and oil of the remaining food difficult to separate through the sieving and flotation separation process to maximize the oil recovery rate and minimize the effect on the operation of the sewage treatment plant during sewage treatment associated with It is an object to provide an apparatus and method.

In order to achieve the above object of the present invention, the food desorption liquid treatment apparatus according to the present invention, the flotation separation tank for oil and water separation for separating the oil contained in the pretreated food desorption liquid using micro-bubbles dissolved in the pressurized water; A reaction agglomeration tank for administering a flocculant to the food desorption liquid from which oil has been removed through the flotation tank for oil and water separation, and forming a floc through rapid and slow stirring; And a flotation separation tank for solid-liquid separation separating the flocks generated in the reaction agglomeration tank by using microbubbles dissolved in the pressurized water.

In addition, the food desorption liquid treatment apparatus according to the present invention, by pressurizing a portion of the treated water discharged from the flotation separation tank for solid-liquid separation with high-pressure air to produce a pressurized treated water in which fine bubbles are dissolved, this separation separation for solid-liquid separation It characterized in that it further comprises a pressurized water circulating device for circulating to the tank and floating separation tank for oil and water separation.

In addition, the food desorption liquid treatment apparatus according to the present invention, the oil storage tank for storing the oil separated in the flotation tank for oil-water separation is further installed, to separate the oil and water by heating the oil stored in the oil storage tank to a constant temperature Further oil refinery is installed.

In addition, the reaction coagulation tank is characterized in that it further comprises a pH adjusting tank for injecting an alkali adjuvant before injecting the flocculant.

In addition, a secondary drum screen for solid-liquid separation of the solids separated in the solid-liquid separation float separation tank for solid-liquid separation is connected.

Thus, the present invention is installed by separating the flotation separation tank for oil-water separation and the flotation separation tank for solid-liquid separation to separate the solids, and maximizes the flocculation reaction by injecting the flocculant into the desorption liquid sufficiently removed oil Solid-liquid separation in the solid-liquid separation tank is performed well, and some of the treated water discharged from the solid-liquid separation tank is pressurized with high-pressure air to generate pressurized water in which fine bubbles are dissolved, and the solid-liquid separation is performed. It is characterized in that the separation of the oil from the flotation tank for oil and water separation by circulating supply to the flotation tank for oil separation and flotation for oil water separation.

As described above, according to the food desorption liquid treatment apparatus of the present invention, by installing a flotation separation tank for oil and water separation in addition to the flotation separation tank for solid-liquid separation to maximize the efficiency of the oil and water separation to improve the efficiency of flocculation flocculation reaction and solid-liquid separation The treatment water quality is improved.

The present invention not only improves the efficiency of solid-liquid separation by increasing the oil recovery rate in the flotation tank for oil and water separation, but also reduces the burden of the oil reforming tank for oil and water separation, and reduces the pollutant load discharged to the sewage treatment plant by improving the treated water quality. Thus, the operation of the sewage treatment plant is stabilized.

With reference to the accompanying drawings will be described in detail with respect to food desorption liquid treatment apparatus according to the present invention.

First, Figure 2 is a schematic configuration showing a coupling structure of the main part of the food desorption liquid treatment apparatus according to the present invention, Figure 3 is a combination of the flotation reaction tank and flotation reaction tank and flotation separation tank for solid-liquid separation shown in Figure 2 Figure 4 is a schematic diagram showing the structure, Figure 4 is a schematic diagram showing the overall structure of the food desorption liquid treatment apparatus according to the present invention.

As shown, the food desorption liquid treatment apparatus according to the present invention is provided with a floating separation tank 10 for oil / water separation for separating the oil contained in the pretreated food desorption liquid by using micro bubbles dissolved in the pressurized water. . And the oil separated in the oil separation tank 10 for separation of oil is sent to the oil storage tank 50, the oil of the oil storage tank 50 is heated to a constant temperature in the oil improvement tank 80 to separate the oil and water. .

At the rear end of the flotation separation tank 10 for oil and water separation, a flocculation reaction tank 20 is formed to add flocculant to the food desorption solution from which oil is removed and to form a floc. The floc formed in the flocculation reaction tank 20 is transferred to the flotation separation tank 30 for solid-liquid separation installed at the rear thereof, and the solid-liquid separation is performed first.

And the sludge separated from the solid-liquid separation flotation tank 30 is sent to the drum screen 40, the solid-liquid separation is made second, some of the treated water separated from the solid-liquid separation flotation separation tank 30 is treated water It is sent to the discharge tank or the sewage treatment plant through the discharge pipe 34.

At this time, some of the treated water separated from the solid-liquid separation flotation separation tank 30 is pressurized by high-pressure air to form a solid-liquid separation separation tank 30 and flotation separation for oil-water separation in the form of pressurized water in which fine bubbles are dissolved. It is circulated and supplied to the tank 10, and the pressurized water supplies fine bubbles to the flotation separation tank 10 for oil and water separation and the flotation separation tank 30 for solid-liquid separation.

Referring to Figure 3, the solid-liquid separation treatment water circulation discharge pipe 62 is installed at the lower end of the solid-liquid separation flotation tank 30, the solid-liquid separation treatment water circulation discharge pipe 62 is a high-pressure air in the treated water A pressure pump 61 for injecting is installed. The first pressurized water circulation pipe 64 is installed between the pressure pump 61 and the floating separation tank 30 for solid-liquid separation, and between the pressure pump 61 and the floating separation tank 10 for oil-water separation. 2 pressurized water circulation pipe (63) is installed.

Therefore, the pressurized water circulated to the lower portion of the oil separation separator 10 for separation of oil and oil through the second pressurized water circulation pipe 64 lowers the concentration of the desorption liquid of the oil separation separator 10 for oil and oil separation, and oil and solids ( SS) Generates microbubbles to facilitate separation.

Hereinafter, a specific configuration will be described together with a process for treating food desorption liquid according to the present invention.

In general, the food desorption solution of the food waste recycling facility is very good compared to the general food desorption solution due to the inflow of a large amount of water during the process. Therefore, SS 30,000 ~ 50,000 desorption solution is generated by removing large coarse coarse matter and heavy specific sediment through primary drum screen, sedimentation tank.

However, a large amount of oil still remains in the pretreated stripping solution. These oils have to be removed first for wastewater treatment because they cause problems such as obstructing contact between microorganisms and air during microbial treatment, and causing problems such as degradation of coagulation efficiency.

To this end, in the food desorption liquid treatment apparatus according to the present invention, the pretreated food desorption liquid is introduced into the lower portion of the flotation separation tank 10 for oil / water separation through the desorption liquid injection tube 12. A portion of the treated water discharged from the solid-liquid separation floatation tank 30 is pressurized with high-pressure air to flow into the lower portion of the flotation separation tank 10 for oil-water separation in the form of pressurized water in which fine bubbles are dissolved. Therefore, the pressurized water in which the microbubbles are dissolved dilutes the high concentration of the desorption liquid of the flotation tank 10 for oil / water separation and generates microbubbles. That is, since the treated water discharged from the solid-liquid separation flotation separation tank 30 has little solids (SS), a portion of the treated water is in the form of pressurized treatment water in which microbubbles are dissolved, and the lower portion of the flotation separation tank for oil-water separation. It is possible to lower the food desorption liquid flowing into the SS 30,000 ~ 50,000 to SS 20,000 ~ 30,000 level, and facilitate the oil and water separation.

Subsequently, the fine bubbles floating in the lower portion of the oil separation separator 10 float the oil contained in the food desorption solution upward. The scraper 16 removes oil from the water surface. At this time, in order to remove only oil without mixing with the water layer, an underwater septum 15 is installed in the floating separation tank 10 for oil / water separation to minimize the flow of the water surface and effectively separate the oil. The oil separated in the flotation separation tank 10 for oil and water separation is discharged into the oil storage tank 50 and the food desorption liquid from which the oil is removed is supplied to the flocculation reaction tank 20.

The flocculation tank 20 adds a flocculant to remove the high concentration of organic pollution load. The flocculation reaction tank 20 is installed between the flotation separation tank 10 for oil and water separation and the flotation separation tank 30 for solid-liquid separation. Therefore, it is possible to maximize the flocculation efficiency by administering a flocculant to the food desorption liquid from which oil is removed.

Preferably, the coagulation reaction tank 20 is composed of a pH adjusting tank 24, a rapid coagulation tank 25, a slow coagulation tank 26, each tank is provided with a stirring device (23). In general, food desorption liquids exhibit low pH due to high concentrations of organic acids. Therefore, it is necessary to calibrate to the appropriate pH for the optimum coagulation efficiency, for this purpose, an alkali adjuvant is injected into the pH adjustment tank (24). For the treatment of food desorption solution, the pH is adjusted to 7 ~ 8 and given sufficient stirring time due to the nature of the food desorption solution with high viscosity, the alkali adjuvant is sufficiently mixed without excessive use of the alkali adjuvant.

Once the pH is corrected, flocculant is administered to increase floc size through rapid (25) and slow (26) agitation. If the reaction fails for a proper time, the amount of chemical use is increased and the appropriate floc is not formed. Therefore, each bath has a reaction time of 15 to 20 minutes depending on the characteristics of the food stripper having a high organic acid and high SS content.

Subsequently, flocs formed in the flocculation reaction tank 20 flow into the flotation separation tank 30 for solid-liquid separation, thereby performing solid-liquid separation. The flotation separation tank 30 for solid-liquid separation separates the floc in the desorption liquid using the pressure flotation separation tank 31. That is, since the fine solids in the food desorption liquid are difficult to be solid-liquid separated in the drum screen 40, the organic solids concentration can be significantly lowered by first removing the fine solids.

Preferably, the flocculant having a flocculant is introduced into the lower portion of the flotation separation tank 30 for solid-liquid separation through the stripping liquid inlet tube 32. The pressurized water in which the microbubbles pressurized by the pressure pump 61 are dissolved is introduced into the lower portion of the flotation separation tank 30 for solid-liquid separation. Therefore, in the flotation separation tank 30 for solid-liquid separation, fine bubbles dissolved in the pressurized water flowing from the pressure pump 61 are combined with SS in the water to generate a sludge layer on the top. Floated sludge is designed to maintain sufficient floating residence time and floating pressure to minimize the water content of sludge generated. By removing the sludge layer with the scraper 36 in the upper part of the floating separation tank, SS drops to 3,000 to 10,000 ppm, and accordingly, BOD and COD also drop largely, thereby reducing organic pollutant load.

And the supernatant separated from the solid-liquid separation flotation tank 30 is sewage-linked to remove residual organic contaminants, and the solids separated by the scraper 36 is solid-liquid separated through the drum screen 40 and dehydrator Reduce the moisture content

In addition, the oil stored in the oil storage tank 50 is separated from the oil and water in the oil improvement tank (80). Preferably, the oil fractionation tank 80 lowers the viscosity by heating a highly viscous oil using a heater and then separates the oil and water by using a difference in specific gravity between water and oil.

As such, the present invention effectively removes the solids and oil of the remaining foods that are difficult to separate through the sieving and flotation separation process to maximize the oil recovery rate and minimize the influence on the operation of the sewage treatment plant during sewage treatment.

1 is a schematic configuration diagram of an example of a food leaving solution treatment apparatus according to the prior art,

Figure 2 is a schematic block diagram showing a coupling structure of the main part of the food desorption liquid treatment apparatus according to the present invention,

3 is a block diagram showing a coupling structure of the flotation reaction tank and flocculation reaction tank and flotation separation tank for solid-liquid separation shown in Figure 2,

Figure 4 is a schematic diagram showing the overall structure of the food leaving solution treatment apparatus according to the present invention.

**** Description of the symbols for the main parts of the drawings ****

10: floating separation tank for oil and water separation 20: flocculation reaction tank

30: floating separation tank for solid-liquid separation 40: drum screen

50: oil storage tank 60: treated water circulator

61 pressure pump 80 oil fractionation tank

Claims (8)

delete delete delete delete In the food desorption liquid treatment method for treating pretreated food desorption liquid, Floating water separation step of separating the oil contained in the pre-treated food desorption liquid using the micro-bubbles dissolved in the pressurized water; An oil storage step of storing the oil separated in the floating water separation step; An oil improvement step for separating oil and water by heating the oil stored in the oil storage step to a constant temperature; A pH adjustment step of adjusting pH by injecting an alkali adjuvant into the food desorption liquid from which oil is removed in the oil and water separation step; A reaction coagulation step including a coagulation agent to the pH-adjusted food desorption solution and including a rapid coagulation step and a slow coagulation step to form a floc by rapid and slow stirring; A solid-liquid flotation separation step of separating solids from the flocs generated in the reaction agglomeration step using micro-bubbles dissolved in pressurized water; A pressurized water circulating step of pressurizing a portion of the treated water separated in the solid-liquid flotation separation step to generate pressurized water in which microbubbles are dissolved and circulating it into the flowing water separation phase and the solid-liquid flotation separation step Food removal solution treatment method characterized in that it comprises a delete delete delete

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