CN-122010310-A - Sewage denitrification and dephosphorization treatment method and system

CN122010310ACN 122010310 ACN122010310 ACN 122010310ACN-122010310-A

Abstract

The application relates to the technical field of sewage treatment, and discloses a sewage denitrification and dephosphorization treatment method based on preposed MABR carbon source diversion, which aims at the difficult problem of carbon source competition in the sewage treatment process with low carbon nitrogen ratio, and the membrane aeration biological membrane reaction unit is arranged behind an anaerobic section and is controlled to operate in a micro-oxygen range of 0.3-0.7 mg/L, and meanwhile, the ratio of nitrate nitrogen to phosphate concentration of effluent is stabilized to be 3.0-5.0, so that the membrane aeration biological membrane reaction unit becomes a carbon source intelligent diverter. In the unit, the residual organic matters are preferentially used for pre-denitrification, and the internal carbon source in the phosphorus accumulating bacteria is completely protected and is specially used for subsequent efficient phosphorus absorption and endogenous denitrification. The application realizes the transformation from 'carbon source competition and intra-bacterial circulation' to 'carbon source pre-diversion according to functions', does not depend on special strains, and has the outstanding advantages of high efficiency, strong stability, low energy consumption and good impact resistance.

Inventors

LIU MENGMENG
CHEN YASONG
SUN WAN
PENG MENGWEN
WANG ZHIYONG
Nie Zhonglin
WANG ZILIN

Assignees

中国长江三峡集团有限公司

Dates

Publication Date: 20260512
Application Date: 20260210

Claims (10)

1. The sewage denitrification and dephosphorization treatment method is characterized by comprising the following steps: S1, anaerobic phosphorus release and carbon storage, namely mixing sewage and phosphorus accumulating bacteria under anaerobic conditions, wherein the dissolved oxygen under the anaerobic conditions is less than or equal to 0.2mg/L; S2, introducing the effluent from the step S1 into a membrane aeration biological membrane reactor, and regulating and controlling the membrane aeration biological membrane reactor to run so as to simultaneously meet the following conditions: The dissolved oxygen of the main body solution in the membrane aeration biological membrane reactor is maintained in a micro-oxygen environment of 0.3 mg/L to 0.7 mg/L; the N/P ratio in the effluent of the membrane aeration biological membrane reactor is stabilized at 3.0 to 5.0; s3, aerobic phosphorus absorption, namely treating the effluent of the step S2 under an aerobic condition; s4, anoxic endogenous denitrification, namely treating the effluent from the step S3 under anoxic conditions.
2. The process according to claim 1, wherein in step S2, the dissolved oxygen level of the bulk solution in the membrane-aerated biofilm reactor and the water-out N/P ratio of the membrane-aerated biofilm reactor are regulated by adjusting the gas pressure inside the membrane module of the membrane-aerated biofilm reactor.
3. The process of claim 2, further comprising the intelligent control step of: according to the ammonia nitrogen and COD concentration of the inlet water of the membrane aeration biological membrane reactor, determining a basic set value of the air pressure in the membrane through feedforward calculation; According to the N/P ratio of the effluent of the membrane aeration biological membrane reactor, comparing the N/P ratio with a target N/P ratio, and determining the adjustment amount of the air pressure in the membrane through feedback calculation; And integrating the basic set value with the adjustment quantity to obtain a final intra-membrane air pressure set value, and controlling the membrane aeration biological membrane reactor to operate according to the set value.
4. The method according to claim 1, wherein in the step S2, the residual biodegradable organic matters in the sewage which are not absorbed by the phosphorus accumulating bacteria in the step S1 stage occupy 30% to 70% of the chemical oxygen demand of the effluent of the step S1.
5. The method according to claim 1, wherein the phosphorus accumulating bacteria in the step S1 and/or the step S3 comprise aerobic phosphorus accumulating bacteria, and the microorganism performing the denitrification function in the step S2 comprises heterotrophic denitrifying bacteria.
6. The treatment method according to claim 1, wherein the treatment method for denitrification and dephosphorization of sewage further comprises refluxing the precipitated effluent after anoxic treatment, and the precipitated sludge to the anaerobic phosphorus release carbon storage stage of step S1.
7. A sewage denitrification and dephosphorization system for carrying out the method of any one of claims 1 to 6, comprising, in order in the sewage flow direction: The anaerobic reaction unit is used for mixing sewage to be treated with activated sludge containing phosphorus accumulating bacteria; The membrane aeration biological membrane reaction unit is internally provided with a membrane component, a gas pressure adjustable gas supply device communicated with the membrane component, a dissolved oxygen monitoring instrument for monitoring dissolved oxygen in the unit and an online water quality analysis instrument for monitoring nitrate nitrogen and phosphate concentration of effluent; The water inlet end of the aerobic reaction unit is connected with the water outlet end of the membrane aeration biological membrane reaction unit; And the water inlet end of the anoxic reaction unit is connected with the water outlet end of the aerobic reaction unit.
8. The system of claim 7, further comprising a precipitation unit, the water inlet end of the precipitation unit being connected to the water outlet end of the anoxic reaction unit, and a sludge return unit connecting the sludge area of the precipitation unit to the inlet of the anaerobic reaction unit; And/or the system further comprises an intelligent control unit, wherein the intelligent control unit is in signal connection with the gas pressure adjustable gas supply device, the dissolved oxygen monitoring instrument and the online water quality analysis instrument.
9. The system of claim 8, wherein the intelligent control unit comprises: Receiving the nitrate nitrogen concentration and phosphate concentration data of the outlet water monitored by the online water quality analysis instrument, and calculating the concentration ratio of the current nitrate nitrogen to the phosphate; comparing the current ratio with a preset target ratio range; and generating a control instruction according to the comparison result, and sending the control instruction to the gas pressure adjustable gas supply device so as to adjust the internal gas pressure of the membrane assembly.
10. The system of claim 9, wherein the intelligent control unit further comprises: Receiving ammonia nitrogen concentration and chemical oxygen demand concentration monitoring data of the effluent of the anaerobic reaction unit or the influent of the membrane aeration biological membrane reaction unit; determining a basic set value of the air pressure in the membrane through a pre-stored feedforward calculation model according to the ammonia nitrogen concentration and the chemical oxygen demand concentration; and on the basis of the basic set value, carrying out feedback adjustment by combining the comparison result of the current ratio and the target ratio to obtain a final intra-membrane air pressure set value.

Description

Sewage denitrification and dephosphorization treatment method and system Technical Field The application relates to the technical field of sewage treatment, in particular to a sewage denitrification and dephosphorization treatment method and a sewage denitrification and dephosphorization treatment system, which are particularly suitable for treating urban domestic sewage and industrial wastewater with low carbon nitrogen ratio and realize efficient, stable and low-carbon removal of nitrogen and phosphorus nutrients. Background With the increasingly strict quality standards of water environment, the focus of sewage treatment has been turned to deep removal of nitrogen and phosphorus nutrients. When the traditional biological denitrification and dephosphorization process (such as A 2/O and variants thereof) is used for treating sewage with low carbon nitrogen ratio (COD/TN <5, commonly referred to as BOD 5/TN < 4), the fundamental contradiction is faced that limited biodegradable organic matters (carbon sources) in the sewage must meet the requirements of heterotrophic denitrification and phosphorus accumulating bacteria (PAOs) anaerobic phosphorus release/synthesis of an internal carbon source (PHA) at the same time, and the two requirements form a strong competition. In order to ensure the denitrification effect, external carbon sources such as sodium acetate, methanol and the like are often required to be added, so that the operation cost and the carbon emission are obviously increased, the sludge yield is increased, and the system regulation is complicated. In order to solve the carbon source dilemma, the industry develops a technical route taking denitrification dephosphorization as a core. For example, the prior art discloses a short-process nitrogen and phosphorus removal system and method for sewage with low carbon nitrogen ratio, the technology uses denitrifying phosphorus accumulating bacteria (DPAOs) as an active carbon source carrier, a carbon source is stored in a PHA form in a bacterial body in an anaerobic section, denitrification and phosphorus absorption are synchronously completed in a subsequent anoxic section, and finally, advanced nitrogen removal is performed through MABR. The technology represents an important research direction at present, but the efficient and stable operation of the technology is highly dependent on the enrichment and metabolic activity of DPAOs which is a special functional flora, while DPAOs has low abundance in a natural system and conventional activated sludge, long enrichment culture period and extremely sensitive to environmental factors such as dissolved oxygen, nitrate concentration and the like, so that the process is slow to start, the requirement on long-term operation stability is high, and potential risks exist in engineering popularization. The Membrane Aeration Biofilm Reactor (MABR) technology is attracting attention because of its bubble-free aeration (oxygen mass transfer efficiency > 80%) and the realization of Synchronous Nitrification and Denitrification (SND). However, in the prior art, MABR is mostly simply "built into" traditional process flows, for example as an aerobic unit to enhance nitrification, or as a unit to provide an anoxic/micro-aerobic environment. Particularly when MABR is placed at the end of the process or as a bulk reactor, its function is defined as "advanced treatment unit" or "special flora reaction unit", failing to reconstruct the carbon source flow direction and microbial metabolic pathways from the system level, its technical potential in terms of source regulation of carbon source distribution has not been effectively exploited. In summary, the current technical route for solving the denitrification and dephosphorization of the sewage with the low carbon-nitrogen ratio mainly follows two modes, namely a carbon source space competition mode represented by the traditional A 2/O and a carbon source bacteria internal circulation mode. The former has inherent contradiction of carbon source distribution, and the latter is subject to engineering application bottlenecks of special strains. Therefore, there is an urgent need in the art for a novel denitrification and dephosphorization method and system that can jump out of the above mode, not rely on the difficult cultivation of special strains, and can fully exploit the technical potential of MABR, so as to realize efficient, stable, energy-saving and easy engineering management treatment for sewage with low carbon nitrogen ratio. Disclosure of Invention Aiming at the problems of strong competition of carbon sources, excessive dependence on special and unstable denitrifying phosphorus accumulating bacteria (DPAOs), single MABR function positioning, insufficient system stability and the like in the prior art, the application aims to provide a sewage denitrification and dephosphorization method and system based on prepositive MABR carbon source diversion. The application changes