Method for performing biological denitrification of wastewater by using residual sludge and biological denitrification system for implementing same

Abstract

The invention discloses a method for performing biological denitrification on wastewater by using residual sludge and a biological denitrification system for implementing the method. The method comprises the steps of (1) performing sequencing batch internal circulation A / O biological denitrification on the wastewater to be treated, and taking the residual sludge discharged after denitrification; (2) performing ultrasonic treatment on the residual sludge to obtain a sludge mixed solution; (3) performing anaerobic fermentation on the sludge mixed solution to obtain fermentation broth, and refluxing the fermentation froth to the wastewater to be treated; and (4) repeating the steps (1)-(3). A filling material is added in an aerobic tank to improve the degradation efficiency of functional microbes to pollutants; tubificidae are loaded on the filling material to prey active sludge so as to realize effective reduction of the residual sludge; and the discharged residual sludge is further treated to obtain fermentation broth serving as a carbon source, so that an additional carbon source does not need to be added, the problem of insufficient denitrification carbon source is solved, and secondary reduction of the residual sludge is realized.

Description

technical field [0001] The invention belongs to the technical field of excess sludge treatment, and in particular relates to a method for biological denitrification of wastewater by utilizing excess sludge and a biological denitrification system for implementing the method. Background technique [0002] Generally, urban sewage can only remove about 25-30℅ of BOD by sedimentation method 5 , Colloids and dissolved organic matter in sewage cannot be removed by precipitation methods, and chemical methods are not suitable for use because of the high cost of chemicals and the poor effect of chemical coagulation to remove dissolved organic matter. Using biological treatment (activated sludge process) is the most economical and effective option to remove organic matter in wastewater. [0003] Nitrogen in wastewater generally exists in four forms: organic nitrogen, ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen. In the common sequencing batch internal circulation A / O biol...

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Problems solved by technology

[0007] Unfortunately, the study found that after water earthworms were introduced into the sewage treatment system, although the reduction of sludge discharge was achieved, the denitrification effect of the system declined.

Ratsak et al. in the Netherlands conducted a research on water earthworm sludge reduction technology with different processes, and found that water earthworms have the effect of sludge reduction in aerobic ponds, but due to the metabolism of water earthworms, a large amount of nitrate is released, making The nitrogen index of the treated water is basically not up to the standard

[0008] However, in order to meet the emission standards of TN, we are faced with the problem of insufficient raw water carbon sources.

Moreover, after being predated by water worms, the remaining sludge has been reduced in volume and quality, and it is difficult to use it again in sewage treatment

Whether it is processing excess sludge or adding external carbon sources will increase the operating costs of sewage treatment plants

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