KR20140004989A - Hybrid thermophilic anaerobic digestion process for the combined treatment of food-waste and pig-manure. - Google Patents

Abstract

The present invention is a composite high temperature anaerobic digestion method of merging the remaining food and livestock waste water, and the high temperature methane fermentation process. The remaining food is crushed and put into an acid digestion tank as a pretreatment step to hydrolyze the treated acid decomposed water and livestock waste water The mixture is adjusted to an appropriate hydrogen ion concentration and introduced into an anaerobic high temperature digestion tank. The biogas generated by fermentation of methane is generated by a cogeneration generator (CHP) and supplied to the transmission transmission line, and the high temperature digestion water is stabilized in a medium temperature digestion tank. As a recycling method;
1) Conventional process consists of one reaction step, but anaerobic digestion reaction consists of two stages of acid fermentation and methane fermentation, so it is divided into one-stage acid digestion tank and two-stage anaerobic high temperature digestion tank. Driving under conditions
2) The methane fermentation reaction temperature has been operated mainly by the medium temperature method (37 degrees C), but by adopting the high efficiency high temperature method (57 degrees C), the methane conversion rate of organic matter is also doubled. The amount is eliminated, the pathogens in the residue and the removal of weed seeds are completely done,
3) Completion of the solids by filtering the stabilized deuterium water by terminating methane fermentation in the mesothermal digestion tank, and the filtrate is safely recycled to the organic method as liquid solution.

Description

Hybrid Thermophilic Anaerobic Digestion Process for the Combined Treatment of Food-waste and Pig-manure.

The technical field of the present invention is a high load high temperature anaerobic digestion, biogas production and cogeneration technology for processing and recycling high concentration organic carbon components and total nitrogen components such as leftover food and livestock wastewater.

Livestock wastewater is considered to be a major cause of eutrophication and green algae of river lakes. Domestic livestock wastewater is 1% of total wastewater, but pollution load based on organic carbon component (BOD) is 15%, which is a source containing high concentrations of organic carbon, phosphorus and nitrogen. The problem of livestock wastewater is pig manure from pig farms of 10 million pigs. Among them, the high concentration effluent discharged from Sluriddon, which is mainly employed in large-scale high-density pig farms, is a malignant organic wastewater. No suitable treatment method has been developed. Wastewater discharged by mixing pig manure and barn wash water is subjected to the first solid-liquid separation to compost solids and to treat only the separation liquid, and the pollution degree is organic carbon (CODcr): 50,000 PPM (PPM), total nitrogen. (TN): 6,000 mph (PPM), about one hundred times that of ordinary sewage.

    Most livestock wastewater treatment plants constructed to prevent water pollution by livestock wastewater adopt the aerobic success method. However, when adopting the aerobic method, as an essential pretreatment, an excessive amount of chemical is administered to coagulate and precipitate high concentrations of fine suspended solids to reduce organic matter concentration, and a lot of power is required for sufficient oxygen transfer for aerobic treatment. The rise is, of course, a concern for secondary pollution due to excessive chemical waste generation.

    The remaining foods have been treated in three main directions: drying, feeding and composting. However, drying has proved to be excessively low in fuel costs and feed efficiency is very low, and compost has failed due to lack of economic efficiency due to low demand for fertilizer due to defects such as high salinity due to Korean food habits. .

          Swine manure emissions are 10 liters / day, approximately 10 times that of humans, and contain high levels of nitrogen and phosphorus. These are nutrients necessary for farming, and when manure is stored and stabilized for about 6 months, it becomes a good liquid fertilizer, and has been used for farming since ancient times. However, due to the high density of pig farming in the world, the livestock wastewater discharged from pig farms not only eutrophizes the surrounding streams, but also the odor and methane gas greenhouse effect caused by long-term storage of pig manure. Was highlighted. Thus, manure is emerging as an environmental problem that is spreading not only in Korea but also in Europe, the United States, and other parts of the world. The interests of environmental authorities and organizations have raised interest in the scale, construction and distribution of hog farms The situation is causing a regulation.

Therefore, the development of a high-efficiency anaerobic method for treating the remaining food and livestock wastewater without removing the fine flotation and producing heat and electricity as the generated gas is an urgent issue required to simultaneously realize environmental conservation and alternative energy development.

  1) Leftovers and livestock wastewater alone cannot activate methane fermentation, because of;

(A) The livestock wastewater has ammonia content, and the activity of methane is lowered due to its toxicity. (B) The remaining foods have high hydrogen ion concentration when directly put into the methaking tank due to low pH PH) inhibits the required methane fermentation activity.

If leftover food and livestock wastewater are mixed and neutralized in advance at an appropriate ratio and put into a high temperature digestion tank with suitable properties, activating methane fermentation can produce biogas with high efficiency.

         1) The remaining foods are crushed and put into an acid digestion tank before being put into the methane fermentation tank to maintain high hydrogen ion concentration (PH) suitable for the acid digestion tank to hydrolyze them with high efficiency.

         2) The methane fermentation temperature adopts the high-efficiency high-temperature method (57 degrees Celsius) instead of the conventional mesophilic method (37 degrees Celsius). Increasing the reaction rate, doubling the conversion rate of organic carbon to methane, disinfecting pathogens in methane fermentation water and removing weed seed completely, terminating methane fermentation and stabilizing liquid fertilizer and compost in the medium-temperature digestion tank Safely use as organic fertilizer.

         3) When the methane fermentation reaction is activated, biogas conversion of organic carbon is improved, biogas production is increased, methane gas content is increased, and the generated biogas is collected by a combined heat power generator (CHP). It converts into electricity or heat, heat meets the heating demand of the high temperature digester, electricity covers the power demand of its wastewater treatment process, and the surplus is sold in conjunction with the transmission prospect.

1) Leftover food and livestock waste water are efficiently combined with the activation of methane fermentation.

2) The methane-validated water sterilized in the high temperature digestion tank is filtered and the solids are composted and the filtrate is recycled into a safe organic liquid fertilizer.

3) The activation of methane fermentation increases the production of biogas, an alternative energy.

   1 is a process chart of the combined high temperature anaerobic digestion method for processing the leftover food and livestock wastewater.

If described in detail by the appendix [Fig. 1];

(1) Remaining foods stored in the leftover food hopper (2) Discharge the remaining foods into the sorting conveyor to sort out the metal cutlery and vinyl, etc., and (3) Crush them into a crusher to grind or grind them. The solution is added to a bath, stirred at 30 ° C. to 40 ° C. for 24 hours, stirred and hydrolyzed under acidic conditions. The carbon dioxide gas produced in the acid cracking tank is discharged, and the acid cracking water is discharged from the livestock wastewater storage tank and (10) mixed with the livestock wastewater separation solution from which the condensate is removed from the solid-liquid separator at an appropriate ratio (5) Put in. (5) In the high temperature digestion tank, the influent is stirred for 10 to 30 days at a hydrogen ion concentration of 6 to 8 and 30 to 80 degrees Celsius and stirred to convert the organic carbon contained into methane-based biogas. The biogas produced is (11) stored in a biogas tank, (12) purified from a gas purifier, and (13) supplied to the CHP as fuel, so that the generated electricity meets the needs of the wastewater treatment process itself. It is fed to the transmission prospective through a two-way power totalizer, and the recovered heat is used to heat the high temperature digester. (6) High temperature digested water is introduced into the medium temperature digestion tank and maintained at 20 to 40 degrees Celsius for 1 to 10 days, after which pathogenic bacteria and weed seeds are removed and gas generation is stabilized, (7) The filtered solids are composted and the filtrate is transferred to the (8) liquid storage tank and recycled as a safe organic fertilizer.

(1) Leftover Food Hopper (8) Liquid Baths
(2) Separation conveyors (9) Livestock wastewater storage tanks
(3) crushers (10) contaminant solid-liquid separators
(4) anaerobic acid digestion tanks (11) biogas storage tanks
(5) Anaerobic High Temperature Digester (12) Biogas Purifier
(6) anaerobic deuterium (13) biogas cogeneration
(7) Filter (14) Agitated Manure

Claims (1)

A method of combining the leftover food and livestock wastewater to produce biogas through a high-temperature methane fermentation process and recycling the digested water to liquid ratio;
A) The remaining food is ground and maintained in a stirred closed acid digestion tank, maintained at 10 to 50 degrees Celsius, and anaerobic hydrolysis treatment is carried out for 1 to 10 days.
B) The livestock wastewater is mixed with 1-10 with respect to the weight of acid-decomposed water 1, and the hydrogen ion concentration (PH) is maintained at 6-8, and maintained at 50-80 degrees Celsius in a high temperature digester for 5-20 days. After high temperature anaerobic methane fermentation, the sterilized high temperature digested water flows into the medium temperature digestion tank,
C) The digested water introduced into the medium temperature digestion tank is maintained at 20 to 40 degrees Celsius for 1 to 10 days and then stabilized.The anaerobic digested water is filtered through a filter to compost solids, and the filtrate is stored and recycled into a safe liquid ratio.
D) The generated biogas is used as fuel for the CHP, the electricity generated from the cogeneration generator is supplied to the self-demand and the transmission prospects, and the recovered heat is used for heating the high temperature digester.
Combined treatment of leftover food and livestock wastewater, characterized by a series of multi-stage processes of anaerobic acid decomposition, high temperature anaerobic methane fermentation, mesophilic anaerobic methane fermentation and cogeneration.

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