Synchronous degradation process and device for COD (Chemical Oxygen Demand) and N (Nitrogen) of high concentration wastewater in same pool

Abstract

The invention relates to a synchronous degradation process and device for COD (Chemical Oxygen Demand) and N (Nitrogen) of high concentration wastewater in a same pool. Two aerating devices are arranged at the bottom of a biochemical pool which is divided into a first cell aerating area and a second cell aerating area with different dissolved oxygen control by a functional separating wall. Wastewater and a return liquid are mixed and aerated at the water inlet of the first cell aerating area, the mixed liquid at the tail end of the first cell aerating area flows into the second cell aerating area and is aerated, and degradation of COD and N is carried out in the first and second cell aerating areas. A part of mixed liquid at the tail end of the second cell aerating area returns to the water inlet of the first cell aerating area while the other part flows into a cement separating device. Cleaned water after cement separation is discharged. The dissolved oxygen control range of the first cell aerating area is 0.1-0.5mg / L, the dissolved oxygen control range of the second cell aerating area according to property of wastewater is 0.1-1.8mg / L. The invention has the benefits that the COD removal efficiency of the biological synchronous denitrification process is improved, synchronous degradation of COD and N in the same pool is realized, and the process can be applied to domestic wastewater treatment. Therefore, the invention is more applied to high concentration industrial wastewater treatment with COD and N.

Description

technical field [0001] The invention relates to a waste water treatment process and device, mainly a high-concentration waste water COD and N synchronous degradation process and device in the same pool. Background technique [0002] The organic matter in wastewater consists of elements such as C, N, and P. Among them, C is the main component of COD, and N includes ammonia nitrogen and total nitrogen. The key problem of water pollution is the pollution of COD and ammonia nitrogen. Therefore, organic wastewater treatment must remove COD and N. [0003] COD degradation is mainly the oxidation reaction of microorganisms in an aerobic environment. The enzymes of microorganisms and the oxygen in wastewater cooperate to oxidize C into CO 2 . The degradation process of N is firstly that organic nitrogen is ammoniated into inorganic nitrogen in aerobic or anoxic environment, then nitrification reaction occurs in aerobic environment, and then reduction reaction occurs in anoxic envir...

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Problems solved by technology

[0006] First, the range of "low dissolved oxygen" in the aeration area set by the process is relatively narrow (value 0.1~0.5mg / L), the total amount of oxygen supply is insufficient, the oxidation of high-concentration COD is not sufficient, and the degradation efficiency of COD is low, so it needs to be extended The biochemical residence time or increase the capacity of the biochemical pool will lead to a decline in the economics of the project;

[0007] The second is that the control of low dissolved oxygen is not stable enough. Since the biochemical pool is aerated with low dissolved oxygen, the aeration volume is small, and the conventional strip aeration method results in uneven aeration. The mud is easy to sink to the bottom, resulting in poor three-phase mass transfer effect of "wastewater oxygen sludge" and a decrease in COD degradation efficiency;

[0008] The third is that the reflux ratio setting of the mixed solution only considers the dilution of COD to improve the water inlet conditions, and does not comprehensively consider the B / C ratio, C / N ratio and toxicity in combination with the wastewater properties. Excessive reflux ratios lead to increased energy consumption. If the reflux ratio is too small, the high-concentration wastewater will inhibit microorganisms, and the COD degradation efficiency will decrease;

[0009] Fourth, the sludge concentration set by the process is high, and the separation of mud and water is difficult. When the MLSS is greater than 7500mg / L, the method of clarification with inclined tubes and inclined plates is used, and the phenomenon of mud in the effluent is serious, and the COD standard is not stable.

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