Optimal control method and control system for aeration and push flow process in oxidation ditch

Abstract

The invention relates to an optimization control method of an oxidation ditch aeration and plug flow process and a control system thereof. The method is characterized by according to technology operation state monitoring data and aiming at oxygenation and plug flow, using different feedforward-feedback control strategy and calculating an aeration energy input value and a plug flow energy input value needed in a current condition; according to current aeration equipment and plug flow equipment conditions, calculating aeration energy of the aeration equipment and plug flow energy of the plug flow equipment and comparing with a preset energy value respectively; if the current energy input values satisfy a requirement, continuously executing a current scheme; if the current energy input values do not satisfy the requirement, entering into a next step; when marshalling operation needs to be adjusted, according to a rule of ''changing a rotating speed w firstly, then changing an immersion depth h and finally changing an opening number N'', generating a marshalling scheme and calculating whether the plug flow energy and the aeration energy in the new marshalling scheme satisfy the requirement; when the plug flow energy and the aeration energy satisfy the requirement, executing the new marshalling scheme; and if any one of the plug flow energy and the aeration energy does not satisfy the requirement, regenerating the marshalling scheme and repeating an energy calculating and comparison process in the step.

Description

technical field [0001] The invention relates to an optimized control method and a control system for an urban sewage treatment process, in particular to an optimized control method and a control system for an oxidation ditch aeration and plug flow process applied in the technical field of urban sewage treatment. Background technique [0002] my country has built nearly 5,000 urban sewage treatment plants, and the oxidation ditch process accounts for a relatively high proportion. Oxidation ditch technology has a long history and is widely used because of its simple construction and operation, denitrification and phosphorus removal functions, strong complete mixing and buffering capacity, and a wide range of adaptability to influent characteristics and scales. However, the energy consumption of the oxidation ditch process is higher than that of the traditional activated sludge process. This is because external energy must be input to maintain the rapid circulation and flow of...

AI Technical Summary

Problems solved by technology

Due to the complex technology of adjusting the position of the inverted umbrella, it is generally seldom adjusted in real time for a long time during operation

[0004] At present, the adjustment and control methods of the oxidation ditch are not mature enough, mainly because the equipment adjustment methods are very different, and the coordinated adjustment of aeration and plug flow equipment is difficult

On the one hand, the adjustment methods of equipment such as aeration discs, flow boosters, and inverted umbrellas are very different, which makes it difficult to quantify and analyze the performance of equipment. The control system must be developed locally according to the characteristics of the equipment.

On the other hand, there are many factors that affect equipment push flow and aeration, and it is difficult to clearly identify them

In the prior art, Computational Fluid Dynamics (CFD) is mainly used to simulate and analyze the associated effects of aeration and push flow, which is costly and time-consuming, and lacks practical evaluation methods in engineering

In addition to the diversity of equipment, the control strategy of oxidation ditch aeration equipment is also not practical enough. For example, the patent document with the publication number CN1966426A proposes to control the frequency conversion blower with dissolved oxygen, but oxidation ditch is rarely used in practice. Blast aeration equipment, the dissolved oxygen concentration mainly indicates the aerobic-anoxic zone, which is difficult to control stably

The patent document with the publication number CN203683313U proposes to use dissolved oxygen to control the grouping of rotating discs and frequency conversion, etc., but the distribution of dissolved oxygen in the oxidation ditch is closely related to the state of the aeration equipment, and there is no state of dissolved oxygen balance. The reading of a dissolved oxygen meter at a certain point is mainly It depends on whether the upstream adjacent aeration equipment is in operation, so it is difficult to guide the adjustment of the operation status of the entire ditch in actual work

The above unfavorable conditions limit the optimal control of oxidation ditch aeration and plug flow process, so it is urgent to establish new understanding methods and equipment

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