Constant-water level CAST wastewater treatment method and system

Abstract

The invention discloses a constant water level CAST wastewater treatment method, which comprises the following steps: A. according to the preset water inflow and water intake time, the wastewater is controlled to enter a CAST pond, and operations of sedimentation and drainage are performed at the same time; B. the wastewater is subjected to aeration by properly adjusting the aeration rate; and according to the acquired dissolved oxygen and oxidation-reduction potential information, the aeration time is controlled; and C. according to the preset sedimentation time, the wastewater is subjected to sedimentation; and after the sedimentation, the step A starts. The invention also discloses a constant water level CAST wastewater treatment system. The invention integrates a multiple water intakeoperating mode and an automatic control system, fully utilizes organic carbon sources in original wastewater, maximally saves additional carbon source quantity and saves energy under the condition ofensuring the quality of the discharged water; moreover, the method also has the advantages of simple process, low operational cost, homogenized water quality, flexible operational management, good shockproof load, small occupied area, difficult sludge bulking and the like.

Description

technical field [0001] The invention relates to the technical field of sewage treatment, in particular to a constant water level CAST sewage treatment method and system. Background technique [0002] CAST (Cyclic Activated Sludge Technology, circulating activated sludge process) is a combination of conventional SBR (Sequencing Batch Reactor, sequencing batch activated sludge process) and ICEAS (Intermittent Cyclic Extended Aeration System, intermittent cycle delayed aeration activated sludge process) ) developed on the basis of technology. With the improvement of nitrogen and phosphorus removal requirements, the conventional SBR process and ICEAS process are difficult to meet the requirements. At the same time, the complete mixed flow state is not good for preventing sludge bulking and also affects the reliability of operation, so the CAST process was developed. [0003] The CAST reaction pool is divided into a selection zone and a main reaction zone. The operation of the r...

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Problems solved by technology

[0011] In the course of realizing the present invention, the inventor finds that there are at least the following problems in the prior art: (1) the traditional CAST process single tank is intermittent water inflow and intermittent water outflow, After decanting, there is a height difference ΔH between the water outlet level and the water inflow level, generally 1-2m. Due to the existence of this variable water head, the lifting height in the previous stage increases

(2) Although the traditional CAST process has good controllability and good denitrification effect, it has the disadvantages of cumbersome operation and high automation requirements, and the traditional CAST process needs to add carbon source in the denitrification process

In order to achieve the purpose of deep denitrification, the operating cost needs to be increased

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