Oxidation ditch denitrification nitrogen removal control system

Abstract

The invention discloses an oxidation ditch denitrification nitrogen removal control system which is characterized in that a partition wall is additionally arranged at the position where a front denitrification area is communicated with an aerobic area to block water flow, and the front denitrification area is communicated with the aerobic area through a pre-buried flow guide pipe at the bottom ofa pool; a water inlet pipeline is led into the front denitrification area, a carbon source adding device is further arranged beside the water inlet pipeline, a water outlet pipeline is led out from awater outlet of the oxidation ditch located in the aerobic area, and a propeller pump is additionally arranged on the partition wall; and three factors of dissolved oxygen DO, nitrate concentration and carbon source concentration of the oxidation ditch are adjusted through four closed loops so as to facilitate linkage control. According to the oxidation ditch nitrogen removal control system, the denitrification nitrogen removal treatment effect can be effectively guaranteed under the condition of sufficient carbon sources by controlling the dissolved oxygen of the internal reflux mixed liquidand the reflux quantity of the internal reflux mixed liquid in the oxidation ditch.

Description

technical field [0001] The invention belongs to the technical field of sewage treatment and relates to an oxidation ditch denitrification and denitrification control system. Background technique [0002] The Carrousel 2000 oxidation ditch adds a horizontal partition wall to the traditional Carrousel oxidation ditch, which separates the unique pre-denitrification zone, making it not only has the characteristics of an oxidation ditch, but also has a typical A The characteristics of the / O process, and its special hydraulic design makes it have the characteristics of high cross-sectional flow and circulating flow, which is as high as 30 to 50 times the influent flow, and the influent from entering to leaving the system, on average, must be in The closed flow line circulates dozens of times, making it a fully mixed circulating flow system with high operational stability and impact load bearing capacity; and the return of the mixed liquid is completely automatic through the water...

AI Technical Summary

Problems solved by technology

However, the adoption of a fixed-speed inverted umbrella surface aerator close to the inner backflow door makes the inner backflow mixed liquid produce higher dissolved oxygen DO, and the mixed liquid backflow "carries" dissolved oxygen DO into the pre-denitrification zone, which will not only consume a large amount of dissolved oxygen in the sewage Part of the carbon source, and the anoxic environment of the denitrification reaction is destroyed, resulting in a decrease in the removal rate of total nitrogen TN and poor denitrification effect

Therefore, there is a contradiction between the nitrification and denitrification process for the difference in the concentration requirements of dissolved oxygen DO and organic matter

[0006] 2) The reflux mixture in the Carrousel 2000 oxidation ditch adjusts the size of the internal reflux flow by adjusting the opening angle of the internal reflux door. There is a large control range, and the internal reflux flow cannot be precisely controlled, which directly affects the removal rate of total nitrogen. This is because the size of the internal return flow directly determines the amount of nitrate concentration entering the pre-denitrification zone

[0007] 3) Since the concentration of organic pollutants in my country's urban sewage is not high, the available carbon source is low, and the lack of carbon source also seriously restricts the biological denitrification efficiency of the Carrousel 2000 oxidation ditch. It is necessary to add a certain proportion of carbon source for denitrification. nitrogen process

[0009] According to the data in the project, the Carrousel 2000 oxidation ditch adopts the CARCon system to control the operation status and oxygenation of the surface aerator, among which the dissolved oxygen DO content is the main control parameter, and the oxidation-reduction potential ORP and influent water flow are the auxiliary parameters. Second-level adjustment of parameters; through the adjustment of dissolved oxygen DO, flow rate, oxidation-reduction potential ORP and other parameters, combined with the adjustment of the return flow in the mixed liquid to obtain the best total nitrogen TN removal rate; but in fact, although the CARCon system is different from the traditional Compared with the control based only on the DO concentration, the ORP and the inner reflux gate are added to form a closed-loop control. The opening angle of the inner reflux gate is determined by the detection value of the ORP to control the internal reflux of the mixed liquid. However, there is an internal The return flow cannot be precisely controlled. Second, there are too many factors affecting the ORP, among which dissolved oxygen DO, pH, sludge concentration MLSS, hydraulic retention time HRT, and reflux ratio are all critical or sensitive to the ORP. Influencing factors, so that the oxidation-reduction potential ORP only plays a rough indicator role, and cannot effectively guarantee the effect of denitrification treatment

[0010] As my country's sewage treatment has stricter requirements on nitrogen and phosphorus, in order to ensure that the total nitrogen reaches the standard, many sewage treatment plants have added external carbon sources, but the current carbon source dosage mainly depends on experience or manipulation The system is complex, there are too many setting parameters, the calculation method is not simple enough, and the practicability is not strong

[0011] At present, most of the Carrousel 2000 oxidation ditches in operation do not carry out chain control of the denitrification system according to the three factors of dissolved oxygen DO, nitrate concentration and carbon source concentration; therefore, seeking a Carrousel 2000 oxidation ditch based on the above The three-factor denitrification control system, which strengthens the denitrification effect, has important practical significance for the design of the Carrousel 2000 oxidation ditch and the current increasingly stringent total nitrogen emission indicators

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