Optimal control method for water inlet flow, unit load and residence time in sewage treatment process

Abstract

The invention relates to an optimal control method for water inlet flow, unit load and residence time in the sewage treatment process. The method comprises the following steps of: determining water inlet flow and water inlet chemical oxygen demand under optimized working conditions in a sewage treatment plant; calculating a water inlet flow set value under the current working condition on the basis of the selected optimized working conditions; establishing a water inlet flow set value control loop, correcting the water inlet flow set value under the current working condition, and thus obtaining a corrected water inlet flow set value; and establishing a water inlet flow set value control loop of which the water inlet flow is changed along with the set value on the basis of the corrected water inlet flow set value. The water inlet flow, unit load and residence time are optimally controlled, so that the treatment capacity and the influence of effluent stability indexes, water inlet loads and hydraulic retention time on the effluent quality are comprehensively considered, and the stability of effluent quality indexes of a sewage treatment system and the treatment capacity of the sewage treatment system are improved; and therefore, the profits of sewage treatment enterprises are improved.

Description

technical field [0001] The invention relates to a sewage treatment optimization technology, in particular to an optimization control method for residence time such as inflow flow unit load and the like in the sewage treatment process. Background technique [0002] How to improve the effluent stability of the sewage treatment system on the premise of ensuring the treatment capacity of the sewage treatment plant is an important problem that needs to be solved. [0003] At present, there are mainly three common control methods for inflow flow: [0004] One is that there is no control over the flow rate, that is, how much sewage comes in within the design range, and the influent flow rate of the sewage treatment plant is not artificially changed. This is a method of sacrificing the stability of the effluent water for the sake of treatment capacity. At present, many BOT (Build-Operate -Transfer, construction-operate-transfer) operators all adopt this method for the pure pursuit ...

AI Technical Summary

Problems solved by technology

This control method is simple to implement, but when the incoming water COD (Chemical Oxygen Demanded, biochemical oxygen demand) fluctuates, the incoming water load also fluctuates accordingly, so the stability of the outgoing water quality is poor

[0006] The third is the fixed value control of the influent load, that is, the control (influent flow × influent chemical oxygen demand concentration) is constant. This method takes into account both the treatment capacity and the stability of the effluent, but the actual application does not consider the load residence time, so the stability of the effluent poor

The disadvantage of this control method is that when the COD of the incoming water changes, the flow of the incoming water will also change, and the hydraulic retention time will also change. In this way, the processing time of the same incoming water load will change, which will inevitably lead to the instability of the effluent water quality.

The above three common influent flow control methods all have the disadvantage of unstable effluent quality.

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