Method for extracting microbial amino acid by sludge acid hydrolysis

Abstract

The invention relates to a method for extracting microbial amino acid by sludge acid hydrolysis. The method comprises the following steps: 1) taking residual sludge discharged from a secondary sedimentation tank of a municipal wastewater treatment plant as raw materials, wherein the moisture content of the residual sludge is between 70% and 95%; 2) putting the residual sludge of which the moisture content is regulated into a steam heating and stirring device, using steam to heat the sludge to 70-85 DEG C, and breaking the floc structure of the residual sludge to enable the residual sludge to be under a flowable state; 3) adding concentrated hydrochloric acid into the sludge under the flowable state, and fully stirring to regulate the pH (Potential of Hydrogen) of the sludge to 0.5-2; 4) putting the sludge of which the pH is regulated into a hydrolysis device, heating to 105-121 DEG C, and keeping the temperature for hydrolysis for 0.5-4 hours; 5) carrying out solid-liquid separation on a mixture which finishes hot acid hydrolysis to independently obtain filtrate and filter slags, and removing insoluble residues, wherein the filtrate contains natural compound amino acid; 6) concentrating or drying the filtrate to obtain microbial amino acid concentrated liquor or powder.

Description

[0001] [technical field] [0002] The invention relates to the field of sewage sludge treatment, in particular to an extraction method for extracting microbial amino acids by acid hydrolysis of sludge. [0003] [Background technique] [0004] With the increase of the sewage treatment rate and the deepening of the treatment degree, the sludge output of the sewage plant is increasing year by year, which causes great harm to the water source, the atmosphere, the land and human health, mainly in the following aspects: (1) The impact on the water source Hazards: During the unmeasured stacking and landfilling of sludge, a large amount of acidic, alkaline, toxic substances and heavy metals in sludge are produced, which flow into surface water sources after rain and penetrate below the surface, causing black and odorous underground water and deteriorating water quality. At present, 60% of the rivers in the country have been polluted by ammonia nitrogen, volatile phenol, and permanganat...

AI Technical Summary

Problems solved by technology

[0004] With the increase of the sewage treatment rate and the deepening of the treatment degree, the sludge output of the sewage plant is increasing year by year, which causes great harm to the water source, the atmosphere, the land and human health, mainly in the following aspects: (1) The impact on the water source Hazards: During the unmeasured stacking and landfilling of sludge, a large amount of acidic, alkaline, toxic substances and heavy metals in sludge are produced, which flow into surface water sources and penetrate below the surface after rain, causing black and odorous underground water and deteriorating water quality

At present, 60% of the rivers in the country have been polluted by ammonia nitrogen, volatile phenol, and permanganate, and the fluoride has seriously exceeded the standard. Coupled with the inflow and infiltration of sludge and wastewater, the water body has lost its self-purification function, affecting the reproduction of aquatic organisms and the utilization of water resources.

(2) Pollution to the atmospheric environment: due to incineration or long-term stacking, the discharged sludge releases a large amount of odor, dioxin, sulfur dioxide and other toxic gases, and dust and fine particle suspension migrate with the wind, resulting in sulfur dioxide in the air and suspended particulate matter exceeded the standard, acid rain and dusty weather occurred frequently

(3) Harm to the land: land erosion, sludge production of about 18 million tons per year, organic matter, heavy metals, pathogenic bacteria and other harmful substances are left in the soil, and hard-to-degrade substances seriously corrode the land and pollute groundwater sources

(4) Harm to human health: Sludge incineration, landfill, and stacking release a large amount of dust, dioxin, sulfur dioxide and other toxic gases, which pose a carcinogenic risk to the human body

The problems in the above-mentioned process are as follows: (1), continuously feeding steam for stirring, destroys the uniformity of the material in the hydrolysis process, cannot guarantee the balance of water in the hydrolysis process, and affects the hydrolysis effect; (2), the material after hydrolysis is directly used The residual pressure is used for filtration. As the filtration progresses, the pressure in the kettle gradually decreases, so that the solid-liquid separation cannot be completed; (3), before the hydrolyzed material enters the filtration equipment, there is no cooling device, and the material relies on natural cooling, which cannot guarantee the hydrolysis reaction. (4) Filtration immediately after the completion of hydrolysis will cause damage to the filtration equipment due to the high temperature of the material, and the solid-liquid separation cannot be completed

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