Method for monitoring biological treatment oxygen uptake rate of sewage and controlling aeration quantity

Abstract

The invention relates to a method for monitoring the biological treatment oxygen uptake rate of sewage and controlling the aeration quantity. The method comprises the following steps: determining the oxygen transfer coefficient KLa(d<-1>) of aeration oxygenation and the saturated dissolved oxygen concentration mg / L under different air flow q, temperature and preset sludge concentration conditions, finding relation of the oxygen transfer coefficient KLa to the air supply amount q and the temperature T, fitting the dissolved oxygen change curve within a period of time under the preset oxygen transfer coefficient KLa(d<-1>) and dissolved oxygen concentration conditions in order to find the oxygen uptake rate within the period of time, utilizing the oxygen uptake rate of a last period of time as the possible oxygen uptake rate of a next period of time, finding the lowest aeration quantity q of the next period time for reaching the preset dissolved oxygen concentration, applying the above found air quantity q into a reactor within a following period of time, determining the dissolved oxygen change curve of the following period of time, and finding the oxygen uptake rate within the following period of time. The method overcomes the defects of large equipment investment, complex construction, low test frequency and the like existing in the prior art. The method enables OUR (oxygen uptake rate) to be continuously monitored only through using a dissolved oxygen probe without an extra auxiliary reactor, an extra dissolved oxygen probe or a sewage transmission device.

Description

technical field [0001] The invention belongs to a process monitoring and control technology of sewage biological treatment, in particular to a method for monitoring oxygen absorption rate and controlling aeration amount of sewage biological treatment. Background technique [0002] The method of sewage biological treatment is also called activated sludge method. Since the invention of activated sludge method in the early 20th century, it has been the main method of domestic sewage treatment in all countries in the world. It uses active microorganisms to oxidize organic matter and ammonia nitrogen in sewage under the condition of providing dissolved oxygen to achieve the purpose of removal. The supply of dissolved oxygen is usually accomplished by blower aeration. Aeration is the main energy consumption in the sewage treatment process, usually accounting for more than 50% of the energy consumption in the sewage biological treatment process. Therefore, on the premise of ensur...

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Problems solved by technology

The intermittent method is to record the value of dissolved oxygen (DO) in the sewage treatment reactor within a certain period of time after the aeration is stopped, and divide the two to obtain OUR. This method has a low measurement frequency and cannot be used as a continuous method. The online monitoring method, and the measured value is generally small; the continuous method is to install a small secondary reactor (or other glass container) next to the main reactor, and the activated sludge mixture is continuously input from the main reactor into the secondary reactor. , and then back to the main reactor, and simultaneously measure the dissolved oxygen concentration in the main and auxiliary reactors. The ratio of the concentration difference and the residence time (HRT) of the auxiliary reactor is OUR. Dissolved oxygen probes are installed in the reactors, and sewage reflux equipment is required, the structure is complex, and equipment investment is increased. Moreover, this method measures the OUR in the secondary reactor and cannot fully reflect the OUR in the main reactor.

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