KR20050048548A - Waste water tretment process from food waste filtrates - Google Patents

Abstract

The present invention is a method for treating food waste, which is separated from the filtrate generated from the food waste before drying and incineration treatment into solids and water using decanta, and treated by the biological treatment and separation membrane method to discharge the treated filtrate. Conventional food waste disposal methods include landfilling, incineration, and composting, but these methods have secondary environmental pollution problems due to leachate, economical cost of disposal, and reliable separate collection. It is under development. In the present invention, in the drying and incineration process, the filtrate discharged from food waste by gravity sedimentation in the dehydrator and storage tank is separated into solids and treatment liquid using decanta, and the treatment liquid generated in this process is a biological treatment process. After entering the membrane process. In the membrane process, odors, chromatic salts, inorganic and organic contaminants are removed and discharged to below environmental standards.

In the membrane process, it is divided into treated water and concentrated water, and the ratio of treated water and concentrated water is separated into 9 (production water): 1 (concentrated water) in the primary ultrafiltration membrane and 4 (production water) in the secondary reverse osmosis membrane. ): 1 (concentrated water). The treated water is discharged and the solids from the concentrate and decanta are sent to the dryer for drying.

In the present invention, as described above, the filtrate generated from the food waste before drying and incineration is separated into solids using decanter, and the treated filtrate is treated using biological treatment and separation membrane and is generated from the concentrated water and decanta generated from the separation membrane. Solid content is a method characterized by being sent to a dryer and dried. In particular, by installing a diatomaceous earth precoat filter in front of the separation membrane process is characterized by extending the life of the membrane.

Description

Waste water tretment process from food waste filtrates including biological treatment and membrane process

Conventional food waste treatment technologies include landfilling, incineration, composting and feed, and ocean dumping. Landfilling is currently suspended from bringing food waste into landfills due to secondary environmental pollution from leachate. Incineration method is very economical because the food waste calorific value is low and there is a lot of moisture is required for the auxiliary combustion device. Composting methods can be handled on the premise that thorough segregation should be carried out. For this reason, only food waste from large catering establishments and large restaurants is processed. Fodder treatment techniques have only been implemented in part because of excessive salt content and nutrient balances in livestock feed, odors in harvesting and transport, and work evasion of harvesting personnel. In the case of dumping at sea, dumping of food waste collected by the local government is carried out on the sea designated by the government. This is not possible due to the backlash of the international community and environmental groups.

As mentioned above, there are problems in each treatment technology, and the problems caused by the above technologies are difficult to fundamentally solve, so the government focuses on reducing the amount of food waste, but there is no significant decrease.

In the present invention, in the process of drying and incineration of food waste, the filtrate generated by gravity sedimentation during the extraction and storage process is subjected to secondary solid-liquid separation using decanta, and in the next step by biological treatment by microorganisms Alcohol and volatile organic substances that are difficult to process in the membrane process are decomposed and transferred to the membrane process. The filtrate introduced into the membrane process through the biological treatment process is subjected to the first ultrafiltration membrane treatment and the second reverse osmosis membrane treatment, and the contaminants are discharged after being treated below the environmental standard value. In each membrane process, the filtrate is separated into treated and concentrated water. The separator is separated into treated water that passes through the microstructure of the membrane surface and concentrated water that cannot pass through the membrane surface. In the present invention, the ratio of the treated water and the concentrated water in the primary ultrafiltration membrane is divided into 9: 1, and the ratio of the treated water and the concentrated water in the secondary reverse osmosis membrane is divided into 4: 1. The concentrated water from the first ultrafiltration membrane process and the second reverse osmosis membrane process and the solids from the decanter are sent to a dryer for drying.

In the specific process, the filtrate separated from the food waste is sent to decanta, which is subjected to ultra-high centrifugal motion, to separate the solids contained in the filtrate and sent to the biological treatment process. Solids generated in this process are transferred to a dryer and dried. In the biological treatment process, anaerobic and aerobic tanks are used to decompose alcohol and volatile organic substances which are difficult to remove from the membrane by anaerobic and aerobic microorganisms. The filtrate, which has undergone biological treatment, is introduced into the first ultrafiltration membrane process. In the first ultrafiltration membrane process, organic pollutants and solids having high molecular weight are removed, and the treated water flows into the second reverse osmosis membrane.

The ultrafiltration membrane module used in the present invention uses a tubular module. Tubular module has the characteristics of small flow rate but durability and less clogging than general module.

Leachate flowed into the reverse osmosis membrane completely removes odor, color and salt, and more than 97% of inorganic and organic pollutants are removed. The treated water after the reverse osmosis membrane has no color and odor, and produces clean treated water which is almost free of inorganic and organic pollutants. Table 1 shows the water quality of the treated water generated in each process . The water thus produced is discharged and the concentrated water is sent to a food waste dryer for disposal.

Table 1

BOD (ppm) COD (ppm) Salinity (%) SS (ppm) Number of filtrate 35,000 47,000 1.6 54,200 Decanter Treated Water 8,500 91,000 1.5 7,300 Biological treatment water 2,350 4,380 1.32 1,250 Ultrafiltration Membrane Treatment 1,250 1,670 1.3 15 Reverse Osmosis Membrane Treatment Water 68 83 0.01 0

1: sump tank

2: decanta

3: pressurization

4: anaerobic tank

5: aeration tank

6: settling tank

7: settling water flow adjusting tank

8 diatomaceous earth precoat filter

9: 1st ultrafiltration membrane

10: Belt press

11: Ultrafiltration membrane treated water flow adjusting tank

12: secondary reverse osmosis membrane

13: micro filter

14: Rootsbrower

15: ultrafiltration membrane supply pump

16: reverse osmosis membrane supply pump

17: reverse osmosis membrane pressure pump

18: Belt press chemical storage tank

19: belt press chemical supply pump

20: sedimentation tank sludge transfer pump

21: Decanta Chemical Storage Tank

22: Decanta chemical supply pump

In the configuration of the present invention, the filtrate separated from the food waste is stored in the first collecting tank. The filtrate is transferred to Decanta No. 2 by a feed pump installed inside the sump. In Decanta No. 2, the coagulant stored in No. 21 is supplied by the No. 22 pump, and the solid content contained in the filtrate is agglomerated by the coagulant, and then discharged into filtrate and solids by centrifugal force. The separated solid is transferred to the dryer for processing. The filtrate is transferred to a pressurization tank three times. In pressurized tank 3, compressed air is blown to remove bubbles and solids that could not be removed from the decanter. The removed solids are transferred to water tank 1 and the filtrate is transferred to anoxic tank 4. In anoxic tank 4, high concentrations of organic matter are decomposed by aerobic microorganisms. The treated filtrate is transferred to aeration tank 5. In the aeration tank 5, a high concentration of organic matter which is not degraded by aerobic microorganisms is decomposed by aerobic microorganisms. The treated filtrate is transferred to settling tank six. In No. 6 sedimentation tank, the solids of filtrate treated by anaerobic aerobic microorganism are separated by gravity sedimentation, and the sedimented sludge is transferred to No. 10 belt press by the No. 20 sludge transfer pump. In belt press 10, the coagulant stored in the reservoir 18 is supplied by the 19th chemical transfer pump, and the sludge aggregated by the coagulant is discharged to the outside, and the treated filtrate is sent to the sump. The supernatant treated filtrate separated from the settling tank 6 is sent to the seventh adjusting tank. The No. 7 flow adjustment tank promotes the flow of the filtrate supplied by the No. 15 ultrafiltration membrane feed pump. The filtrate supplied by No. 15 ultrafiltration membrane feed pump is introduced into No. 8 diatomaceous earth precoat filter. In the diatomite precoat filter No. 8, diatomaceous earth is coated on the filter element to remove fine solids and fatty components contained in the filtrate. The treated filtrate is transferred to ultrafiltration membrane 9 times. Ultrafiltration membrane 9 removes ultra-fine particulate matter and high molecular weight organic matter. After treatment, the concentrated water is sent to a dryer for drying. The treated water is sent to No. 11 reverse osmosis flow control tank. The 11 reverse osmosis flow regulating tank adjusts the flow rate supplied by the 16 reverse osmosis feed pump. The treatment filtrate supplied by the No. 16 reverse osmosis feed pump is transferred to No. 13 microfilter. Microfilter 13 removes solids that can enter the outside. The treated filtrate is transferred to reverse osmosis membrane 12 by means of a pressure pump 17. Pressurized pump 17 maintains the pressure beyond the osmotic pressure necessary for the reverse osmosis membrane. Reverse osmosis membrane 12 removes more than 97% of low molecular weight organic and inorganic materials, salts, colors and odors. The treated water thus removed is discharged through the discharge tank because it is treated at or below the environmental discharge standard. The concentrated water separated at 12 reverse osmosis is sent to a dryer for drying.

The effect of the present invention is continuous by removing the solids by using decanta, a high speed centrifugal separator, which is the biggest problem generated in the food waste treatment method by currently used dry and incineration treatment, and then performing biological treatment and membrane treatment. A stable water quality can be obtained. In addition, in the case of a general membrane facility, there is a difficulty in secondary treatment of concentrated water, but in the present invention, the concentrated water is dried by using a dryer to reduce food waste, thereby solving the problem of generating concentrated water, which is a cloud point of the membrane.

In the case of the membrane, the membrane module was used without the use of flat membrane or hollow fiber, which significantly reduced the blockage of membrane caused by high concentration of organic substances such as protein, fat and carbohydrate in food waste. In addition, by installing diatomaceous earth precoat filter in front of the membrane process, the pollution load to be received in the primary ultrafiltration membrane was reduced to extend the life of the ultrafiltration membrane.

1 is a view showing a treatment process and a treatment apparatus of the present invention.

Claims (3)

Separation of food wastes using decanta to separate solids and treatment filtrates to treat wastewater by biological treatment and membrane treatment. The method of claim 1, wherein the solids generated in the decanter and the concentrated water generated in the separator using a dryer. The method of claim 1, wherein a diatomaceous earth precoat filter is installed at the front end of the separation membrane process to extend the life of the ultrafiltration membrane.