High-temperature micro-aerobic-anaerobic digestion device and method for organic sludge

Abstract

The invention discloses an organic sludge high-temperature microaerobic-anaerobic digestion device and method. The method is characterized in that firstly organic sludge is subjected to high-temperature microaerobic digestion, after the high-temperature microaerobic digestion is ended, the digested sludge enters a pH value adjusting tank from a discharge port through a pipeline, alkali liquor is put in the pH value adjusting tank so as to adjust the pH value of the material in the tank, and the sludge remains for 3-5 hours in the tank so as to release dissolved oxygen in the sludge; then the sludge is fed into an anaerobic fermentation reactor by using a pump and remains for 6-20 days, thus the anaerobic digestion process is completed. The method has the beneficial effects that the first half of the organic sludge digestion process is a self-heating type high-temperature microaerobic digestion process rather than a self-heating type high-temperature aerobic digestion process; the amount of air supplied in the self-heating type high-temperature microaerobic digestion process is limited, and VFA (volatile fatty acids) are easily generated under an oxygen limiting condition and easily generate methane under an anaerobic condition, therefore, the further digestion of the sludge in the second half of the anaerobic digestion process is facilitated so as to generate methane, the aeration rate can also be reduced, and the energy consumption is reduced.

Description

technical field [0001] The invention relates to the field of solid waste treatment, in particular to a high-temperature micro-aerobic-anaerobic digestion device and method for organic sludge. Background technique [0002] With the development of social economy and urbanization in our country, the amount of urban sewage is constantly increasing. It is predicted that in 2010 my country's urban sewage discharge will reach 44 billion m 3 / d; will reach 53.6 billion m in 2020 3 / d. Although my country's sewage treatment capacity and treatment rate are not high at present, urban sewage treatment plants discharge about 300,000 tons of dry sludge every year, and it is also growing at a rate of 10% per year. [2] . my country's existing sewage treatment plants have the phenomenon of heavy water and light mud. A large part of the sludge has not been stabilized and harmless treated, and the sludge treatment facilities have not been effectively operated. The sludge has not been prope...

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Problems solved by technology

[0006] The high-temperature micro-aerobic stage of the preparation process has the problem of difficult oxygenation. In actual operation, under the high temperature condition of 55°C to 70°C, the dissolved oxygen concentration is very low, and the oxygen mass transfer efficiency of the semi-solid material is low, and the oxygenation is very difficult. Therefore, it is difficult for this method to reach the aerobic state according to the content disclosed in the text. If the aerobic condition cannot be reached, the first stage cannot release enough heat, and the organic solids are easy to anaerobic acidification, and the pH value of the sludge flowing out from the first stage is relatively low. low, leading to the inability to produce biogas in the second stage anaerobic digestion process, and the anaerobic digestion residence time is long; in addition, according to the content currently disclosed in this method, it is difficult to control the temperature of mesophilic anaerobic digestion to the target temperature, because the heat exchanger recovers The waste heat is low (that is, the temperature difference between 55°C ~ 70°C and 35°C ~ 40°C is very small), and it is difficult to achieve the heat preservation effect; due to the long residence time and large volume of the anaerobic pool, the heat preservation effect is achieved through the heat exchanger in winter just lower

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