Energy saving biological sewage treating method of low soluble oxygen filament bacteria sludge expansion

A technology for biological sewage treatment and sludge bulking

Active Publication Date: 2005-03-02
SDIC XINKAI WATER ENVIRONMENT INVESTMENT CO LTD
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  • Application Information

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Problems solved by technology

In addition, many sewage treatment plants have adopted a conservative approach when designing, and the res

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  • Energy saving biological sewage treating method of low soluble oxygen filament bacteria sludge expansion
  • Energy saving biological sewage treating method of low soluble oxygen filament bacteria sludge expansion

Examples

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Embodiment 1

[0043] The actual domestic sewage in a residential area is used as raw water (pH=7.2~7.8, COD=160~655mg / L). The selected improved A / O process reactor has an effective volume of 66L, the MLSS in the reaction tank is about 3000mg / L, and the reaction temperature is between 20 and 23°C. The sludge reflux ratio is 85-105%, and the residence time in the secondary settling tank is more than 2.5 hours. Reduce DO concentration from 2.0mg / L to 0.4-0.8mg / L. Filamentous bacteria sludge bulking occurs. The COD removal rate is basically not affected, and remains at about 90%. The removal rate of SS is improved, and SS cannot be detected in the effluent. TN removal rate increased from 30-45% to 55-75%. It can save 15-18% of the aeration oxygen supply.

Embodiment 2

[0045] An urban sewage treatment plant in Beijing adopts the oxidation ditch process, and currently treats 170,000 m3 of water 3 / d. Its main process parameters: sludge age of 16 days; reflux ratio of 100-120%; sludge concentration of 4000-6000mg / L; oxidation ditch hydraulic retention time of about 16.8 hours. The design residence time of the secondary sedimentation tank of the sewage treatment plant is 3.4h, the actual operating water volume has not reached the design water volume so far, and the actual residence time of the secondary sedimentation tank is about 4.0h. The aeration rate will be low, and when DO is reduced to 0.3-0.8 mg / L, filamentous bacteria sludge bulking will occur. The quality of the treated effluent remains good. COD, BOD 5 , SS and ammonia nitrogen removal rates are still maintained above 90%.

Embodiment 3

[0047] An urban sewage treatment plant in Chongqing adopts the improved oxidation ditch (A / O process) process, and the current treated water volume is 7000m 3 / d. The sludge age is 10-15 days; the sludge concentration is about 5000mg / L; the total nominal residence time of the oxidation ditch is about 21.2 hours; the reflux ratio is about 100%. The design stop time of the secondary sedimentation tank is 5.2 hours, and the actual stop time is about 7.5 hours. After adopting low dissolved oxygen operation, the dissolved oxygen concentration in the oxidation ditch is reduced from the original 2.0 mg / L to below 1.0 mg / L, mostly between 0.5 and 0.8 mg / L. SVI rose from 70mL / g to above 110mL / g. The daily power consumption of the aeration equipment is reduced by about 20% compared with the original one. The effluent COD, BOD, and TP concentrations remained at the original level. The removal rate of TN is significantly improved, and the concentration of TN in the effluent is reduced...

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Abstract

The present invention belongs to the field of biological sewage treating technology. The present invention features that the biological sewage treating process includes the following steps: aeration of sewage in aeration tank with mixed active sludge liquid and dissolved oxygen concentration of 0.4-0.8 mg/L; deposition in secondary settling tank for water-sludge separation, overflowing supernatant, returning partial sludge to the aeration tank in the reflux ratio of 85-105 %, and exhausting other sludge; and stagnating active sludge in the secondary settling tank for not less than 2.5 hr while active sludge concentration is 800-3000 mg/L, or less than 4 hr while active sludge concentration is 3000-7000 mg/L. The present invention utilizes filamentous bacteria to raise sewage treating efficiency.

Description

technical field [0001] The invention relates to an efficient and energy-saving sewage biological treatment method, which is suitable for treating domestic sewage and industrial waste water. Background technique [0002] Sewage biological treatment is a treatment process that uses mixed cultured microorganisms to remove organic matter. This is a process close to natural purification. During the operation, bacteria and filamentous bacteria grow together to form a microbial ecosystem. There is a dynamic balance relationship between the two types of microorganisms in time and space. In the activated sludge floc, filamentous bacteria form the skeleton of the sludge floc, and other bacteria and micellar bacteria attach to it to form a larger and stronger sludge floc. Filamentous bacteria play a great role in ensuring the strength of sludge flocs. If there is a lack of sufficient filamentous bacteria, the strength of sludge flocs will decrease, and at the same time, the shear resi...

Claims

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Application Information

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IPC IPC(8): C02F3/12C02F3/34C02F11/02
CPCY02W10/10Y02W10/20
Inventor 彭永臻陈滢王淑莹
Owner SDIC XINKAI WATER ENVIRONMENT INVESTMENT CO LTD
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