An aeration control system and method based on an oxygen consumption rate measuring instrument

Abstract

The invention discloses an aeration control system. The system comprises a data acquisition unit, a PLC (programmable logic controller) control unit and an aeration unit, wherein the data acquisition unit comprises an OUR (oxygen uptake rate) tester and a DO (dissolved oxygen) tester, and the aeration unit comprises an air blower, a micropore aeration head and a flowmeter. The invention further provides an aeration control method adopting the aeration control system. System automatic control software calculates the aeration quantity required to be supplied in combination with the OUR value and DO value automatically acquired by an online tester as well as the OTE value calculated according to the OUR value and the aeration quantity by inputting an automatic control algorithm, a signal is output to change the flow of air blowing, the DO is stabilized at the set value, the deviation doesn't exceed 0.5 mg / L, dynamic balance of supply and demand of oxygen is realized, the problem of poorer effluent quality due to insufficient oxygen supply can be solved completely, besides, energy waste caused by excessive aeration can also be reduced, and the function of evaluating the performance of the aeration system is realized.

Description

technical field [0001] The invention relates to the field of sewage treatment, in particular to an aeration control system and an aeration control method based on an oxygen consumption rate measuring instrument. Background technique [0002] In the current stage of my country's industrial development and energy utilization, energy conservation and emission reduction is still a very important issue. Currently. The energy efficiency of my country's urban sewage treatment is still at a relatively low stage, and the high energy consumption per ton of water is still relatively high; as we all know, the sewage treatment industry is a high energy-consuming industry. In 2012, the total power consumption of my country's sewage treatment industry was as high as 12.5 billion kWh, and the unit power consumption was 0.29 kWh / m 3 , if the electricity price is 0.7 yuan / kWh, the total electricity fee will be nearly 9 billion yuan, and at this stage, there are still a large number of sewag...

AI Technical Summary

Problems solved by technology

[0004] At present, the most common method of aeration control in China is still a relatively extensive manual debugging method. The aeration volume is usually determined according to the operator's experience. If the effluent water quality does not undergo long-term and obvious fluctuations, the aeration volume will not be adjusted Real-time adjustment; once the operating conditions change, the adjustment of the aeration volume is still only adjusted up and down according to experience, resulting in insufficient or over-aeration problems, and even the aeration system of some treatment plants is under normal load for a long time Running under the state, not only does not guarantee the quality of the effluent water, but also causes a lot of waste of energy consumption

Moreover, most of the control strategies do not involve the mass transfer efficiency of oxygen, and the relationship between the aeration rate and the conversion rate cannot be accurately grasped, resulting in inaccurate control of the aeration rate.

[0005] DO (dissolved oxygen) control method is when the feedback DO value is greater than the set value, close the valve opening and reduce the blast volume; if the feedback DO value is less than the set value, it will increase the air volume to increase the DO value, which causes The problem is that the data fluctuates a lot

For systems that use ORP (oxidation-reduction potential) and pH for aeration control, since there is no direct linear relationship between ORP and pH and aeration volume, and the ORP value is seriously delayed in a short period of time, it is very difficult in the nitrification-denitrification process. Difficult to determine accurately, not widely used in practical applications

The basic principle of aeration control using water quality indicators as feed-forward is to calculate the amount of oxygen that needs to be provided through the concentration of pollutants. However, most of the sewage water quality indicators rely on experimental measurements, and the measurement time takes hours or even days. This has an impact on real-time control. not big

Online water quality testing instruments also have a delay of several hours, are expensive, and have not yet been fully popularized

[0006] Intermittent aeration makes the aerobic pond alternate between aeration and non-aeration by repeatedly starting and stopping the blower, which is simple and practical, but the control performance is unstable. The blower is generally at the maximum load, and the energy consumption is high, and will reduce Fan life

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