Dissolved oxygen control device of Orbal oxidation ditch biological denitrification process and its method

Abstract

The invention relates to dissolved oxygen controlling device in the Orbal oxidation ditch denitrifying technology as well as the method, which belongs to the activated sludge process intellectually control domain. The traditional constant aerating way in present technologies has poor denitrifying effects and it's a waste of energy. The data signal output interface connects the process controller, the outer ditch aerate meta-frequency controller is installed in the process controller, it is connected to the outer, center and inner ditch meta-frequency air blower through the outlet end of the process controller; the meta-frequency air blower is connected to the outer, center and inner ditch aerating end. The incipient dissolved oxygen value is settled by the active sludge reaction kinetics; the process controller is controlled by the computer, the aerate volume of the air blower is controlled by the meta-frequency controller of the three ditches; when the water quality changes, the aerate volume is regulated according to the conditions and settled regulations of the dissolved oxygen in all the ditches. The nitrogen removal rate is 80% or higher in the invention while the energy consumption can be decreased by 30% or more.

Description

technical field [0001] The technical field to which the invention belongs is the field of intelligent control of activated sludge method sewage biological treatment system. Background technique [0002] Problems Existing in Orbal Oxidation Ditch System and Its Denitrification Operation [0003] 1. The Orbal oxidation ditch system is a multi-ditch (usually three ditch) single-sludge delayed aeration activated sludge system. Sewage and return sludge enter the system from the outer ditch, flow through the middle ditch and inner ditch in turn, and then enter the secondary settling tank. Each channel is a relatively independent complete mixing system in which the mixed liquid circulates continuously. In a typical three-channel system, the dissolved oxygen (DO) in the outer channel, middle channel and inner channel is generally controlled between 0-0.5 mg / l, 0.5-1.5 mg / l and 2-5 mg / l. This stepped distribution of dissolved oxygen is beneficial to save aeration energy consumptio...

AI Technical Summary

Problems solved by technology

Due to the lack of effective control and management methods, the concentration of total nitrogen in the effluent of many sewage plants is too high, and the energy-saving advantages and denitrification functions of the oxidation ditch process have not been brought into play, and even the normal organic matter degradation and nitrification functions cannot be exerted.

At present, although many domestic sewage treatment plants have installed online monitoring instruments such as dissolved oxygen (DO) meters, oxidation-reduction potential (ORP) meters and pH meters, but in the actual operation process, due to lack of management experience and professional knowledge, they have to Still using the traditional method of constant aeration

The operation mode of constant aeration rate is difficult to adapt to the change of water quality and water volume, and adjust the aeration rate according to the reaction process, which will cause a lot of waste of energy consumption, and lead to unsatisfactory denitrification effect and unstable system operation

Insufficient or excessive oxygen in the aeration tank will lead to the deterioration of the living environment of the sludge, resulting in a decline in the treatment effect and unstable operation of the system: when the oxygen is insufficient, on the one hand, the filamentous bacteria in the aeration tank will reproduce in large numbers, and eventually produce Sludge bulking; on the other hand, a decrease in effluent quality due to reduced growth rates of other bacteria

However, when the oxygen is excessive (that is, excessive aeration), it will cause the suspension of the suspended solids to deteriorate due to the destruction of the activated sludge flocs, and at the same time make the aeration energy consumption too high

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