Optimization control apparatus for denitrification carbon source addition in AO process

Abstract

The invention provides an optimization control apparatus for denitrification carbon source addition in the AO process. The apparatus comprises an A pool, an O pool, a first pipeline, a second pipeline, a third pipeline, an agitator, a water inlet flowmeter, a water inlet COD analyzer, a water inlet ammonia nitrogen analyzer, a dissolved oxygen instrument, a first nitric acid nitrogen sensor and determinator, a second nitric acid nitrogen sensor and determinator, a frequency conversion internal reflux pump, a central control system, a carbon source addition flowmeter, a frequency conversion carbon source addition pump and a carbon source box. The problems of poor denitrification stability, low efficiency and feedback delay existing in a traditional biological A/O denitrification technologyare solved, and the problems existing at present that the control precision is insufficient, the carbon source waste is easily caused, the production cost is increased, and the water output which is stably up to the standard is difficult to be ensured are also solved.

Description

technical field [0001] The invention relates to the field of sewage treatment, in particular to an optimization control device for adding a denitrification carbon source in an AO process. Background technique [0002] In recent years, with the release of the "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (Draft for Comment), cities around the world have issued local standards one after another, stipulating stricter discharge limits for various pollution indicators of urban sewage plants. The main contradiction of sewage treatment has gradually changed from the removal of organic pollutants to the removal of nitrogen and phosphorus pollutants. All sewage plants must be equipped with necessary treatment facilities to further improve the denitrification capacity of sewage treatment plants and improve the removal efficiency of TN. [0003] The biological denitrification process is mainly divided into two parts, that is, the conversion of ammonia nitrogen into ...

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Problems solved by technology

If the nitrate concentration in the raw water is low, this kind of control method may cause excessive dosing of carbon sources, resulting in excessive concentration of organic matter in the effluent water and waste of carbon sources; if the concentration of nitrate in the raw water is high, it may cause Insufficient dosage, resulting in too high concentration of nitrate in the effluent and excessive total nitrogen (TN) in the effluent

The second control method is based on the influent flow rate and the concentration of ammonia nitrogen. The calculated theoretical addition value will be quite different from the engineering practice, which will lead to inappropriate carbon source addition and a greater risk of exceeding the standard. In the end, PLC parameters can only be manually corrected, which is difficult to manage and often has the risk of exceeding the standard

The third control method is improved compared with the simple second control method. If the phenomenon of exceeding the standard occurs, the nitrate nitrogen parameter of the effluent can be fed back, and then the carbon source can be corrected. However, when the effluent exceeds the standard, it is difficult to immediately correct the PLC The control system is corrected. After modifying the dosing amount, it needs to be delayed at least after the residence time of the sewage in the biochemical tank.

[0006] The above three control methods only control the carbon source dosing based on the nitrogen index of the influent and effluent water, but ignore the characteristics of the A / O process. The characteristic is that the nitrifying liquid is returned to the front denitrification through the internal return pump. Reaction pool, its denitrification reaction conditions and removal efficiency are greatly affected by internal reflux

Relative to the influent flow rate, if the internal return flow rate is too low, the denitrification potential in the anoxic zone will not be fully utilized, and the upper limit of the removal rate will drop. At the same time, the primary carbon source in the influent water will flow to the aerobic zone, increasing the oxygen consumption of the system; If the flow rate is too high, on the one hand, it will increase the cost of backflow, and at the same time, it will cause a large amount of dissolved oxygen in the aerobic zone to enter the anoxic zone, thereby destroying the denitrification environment. Therefore, a control system that can solve the above problems is urgently needed

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