Method and device for low-temperature drying of residual activated sludge from sewage treatment

Abstract

The invention discloses a method and device for low-temperature drying of residual activated sludge from sewage treatment. The device comprises sludge freezing equipment, a sludge maintenance chamber, a sludge unfreezing and primary dehydrating device, sludge dehydrating equipment and a sludge airing device; and the residual activated sludge, which is obtained after primary dehydrating treatment is conducted, of a sewage treatment plant is treated by the sludge freezing equipment, the sludge maintenance chamber, the sludge unfreezing and primary dehydrating device, the sludge dehydrating equipment and the sludge airing device sequentially to obtain sludge subjected to low-temperature drying. According to the method and device for low-temperature drying of the residual activated sludge from sewage treatment, through cooperation of the sludge unfreezing and primary dehydrating device, the sludge dehydrating equipment and the sludge airing device, the sludge is continuously dehydrated and aired, a sludge drying cycle is shortened, and a drying effect is obvious. All drying processes are conducted under conditions of normal temperature and temperature lower than the normal temperature, and volatile gas which is generated due to secondary fermentation of microorganisms in the sludge is reduced, so that pollution is reduced. According to the method and device for low-temperature drying of the residual activated sludge from sewage treatment, the sludge is directly frozen, no other chemical agents need to be added, the drying cost is reduced, and meanwhile, the biology characteristics of the sludge remain unchanged, so that a foundation is laid for resource utilization of the sludge.

Description

technical field [0001] The invention belongs to the technical field of sludge treatment, and in particular relates to a low-temperature drying method and device for residual activated sludge in sewage treatment. Background technique [0002] A large amount of excess activated sludge is produced in the process of sewage treatment, and the investment and operation costs of excess activated sludge are relatively high, which brings a heavy burden to sewage treatment. The forms of the existing sewage treatment residual activated sludge drying process: mechanical dehydration, sludge drying or mechanical dehydration + sludge drying; the main technical measures adopted are: (1) Mechanical dehydration stage: the remaining activated sludge needs to be dehydrated first Quenching and tempering, mainly by adding PAC, PAM, lime and other measures to improve the dehydration performance of the sludge, and then using mechanical dehydration equipment for dehydration, the disadvantage is that ...

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Problems solved by technology

The forms of the existing sewage treatment residual activated sludge drying process: mechanical dehydration, sludge drying or mechanical dehydration + sludge drying; the main technical measures adopted are: (1) Mechanical dehydration stage: the remaining activated sludge needs to be dehydrated first Quenching and tempering, mainly by adding PAC, PAM, lime and other measures to improve the dehydration performance of the sludge, and then using mechanical dehydration equipment for dehydration, the disadvantage is that the moisture content of the sludge can only be reduced to about 60%, and at the same time, adding lime Finally, the pH value of the mud cake is strongly alkaline; (2) sludge drying stage: the existing technology uses artificial heat sources to make the remaining activated sludge dry and dehydrate by directly or indirectly heating up and evaporating the water in it. The temperature is above 100°C, and its disadvantages are: high energy consumption, changing the biological characteristics of sludge, and producing a large amount of toxic and harmful gases in the process

[0003] CN105461182A discloses a biological sludge reduction method, which integrates aeration, ultrasonic treatment, hydrolysis, anaerobic fermentation, conditioning, concentration, refrigeration treatment, thawing, and vacuuming technologies, and can reduce sludge Chemical treatment, but this technology has the disadvantages of long reduction period, high cost, inconvenient operation, need to add additional chemicals, and high pH of sludge after reduction

CN102815848A and CN102815848B disclose a high-efficiency drying process for excess sludge. This method integrates anaerobic fermentation, vacuum preloading and freeze-drying technologies, and can effectively dry sludge. However, this technology has a drying cycle Disadvantages of length, high cost, need to add additional chemicals, inconvenient operation, and ineffective drying effect

CN105330111A discloses a method for drying surplus sludge, which improves the existing surplus sludge treatment, but this method has the disadvantages of long drying period, high cost and inconspicuous drying effect

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