阅读说明：本技术 一种利用混凝剂促进厌氧氨氧化菌快速颗粒化的方法 (Method for promoting rapid granulation of anaerobic ammonium oxidation bacteria by using coagulant ) 是由 宫徽 许恩惠 刁思圆 戴晓虎 顾国维 于 2021-09-30 设计创作，主要内容包括：一种利用混凝剂促进厌氧氨氧化菌快速颗粒化的方法,通过在颗粒化形成阶段和成熟阶段采用适合的混凝剂投加量,控制颗粒化不同阶段微生物聚集体胞外聚合物的蛋白比浓度和Zata电位值可以实现快速颗粒化。本发明能够快速实现厌氧氨氧化菌的颗粒化,增强厌氧氨氧化菌沉降性能,不易流失,增强厌氧氨氧化菌抗冲击、抗毒害能力,提高厌氧氨氧化工艺稳定性,增加厌氧氨氧化菌种生物量,负荷高,占地少,投资成本低；且节约了大量时间,流程简单实用,无二次污染。(A method for promoting quick granulation of anaerobic ammonium oxidation bacteria by using a coagulant is characterized in that proper coagulant adding amount is adopted in granulation forming stage and maturation stage, and the protein specific concentration and the Zata potential value of microorganism aggregate extracellular polymers in different granulation stages are controlled to realize quick granulation. The anaerobic ammonium oxidation bacteria granulation method can rapidly realize the granulation of the anaerobic ammonium oxidation bacteria, enhance the sedimentation performance of the anaerobic ammonium oxidation bacteria, is not easy to run off, enhance the impact resistance and the toxicity resistance of the anaerobic ammonium oxidation bacteria, improve the stability of the anaerobic ammonium oxidation process, increase the biomass of the anaerobic ammonium oxidation bacteria, and has the advantages of high load, small occupied area and low investment cost; and saves a large amount of time, and the flow is simple and practical, and has no secondary pollution.)

1. A method for promoting rapid granulation of anaerobic ammonium oxidation bacteria by using a coagulant is characterized by comprising the following steps:

the first step is as follows: the biological pond is operated in a sequencing batch mode, and the operation process comprises water feeding, stirring, standing and water discharging;

preparing 30g PAC/L aqueous solution, determining the specific concentration of extracellular polymeric substance protein of the microbial aggregate at the moment to be 20mg/g MLVSS, determining the Zata potential value to be-21 mV, and determining the ratio of the volume of 30g PAC/L coagulant to the volume of the pool volume to be 1: adding 80-100 of the adding amount into a biological pond to promote the secretion of extracellular proteins, gradually increasing the specific concentration of the extracellular polymeric proteins to 80mg/gMLVSS, and increasing the Zata potential value to-15 mV to ensure that microorganisms can form aggregates;

when the sedimentation time of the biological pond is shortened to 10min, the water begins to be drained, and the drainage ratio is 40-60%;

the hydraulic shear rate of the biological pond is improved by 10s^-1；

After elutriation and selection actions of sedimentation selective pressure and hydraulic shearing selective pressure, a large amount of extracellular proteins are secreted by the intercepted microorganisms to reduce the electronegativity of the microorganisms, and the microorganisms are flocculated again under the action of PAC to form a microorganism aggregate with the PAC as a framework, meanwhile, a flocculation phenomenon similar to 'net catching rolling sweeping' appears around an aggregate inner core due to a large amount of added PAC, and the newly formed microorganism aggregate gradually becomes compact under the scouring action of hydraulic shearing force and is compressed to be spherical under the adhesion action of PAC to form an aggregate which is obviously observed in a fine particle state by naked eyes;

the second step is as follows: after forming visible particles, the volume ratio of 30gPAC/L coagulant to the tank volume of 1: adding the 120-140 adding amount into a biological pond, and maintaining the specific concentration of the extracellular polymeric protein of the microbial aggregate at 140mg/gMLVSS and the potential value of Zata at-10 mV; PAC flocculation, sedimentation selective pressure and hydraulic shearing selective pressure are simultaneously used; the concentration limit of the influent substrate is set to stabilize the granular sludge to be more than 0.45mm in particle size, so that the mature granular sludge is obtained.

Technical Field

The invention belongs to the technical field of water treatment.

Background

In recent years, a novel denitrification technique by anammox has attracted much attention as an economical, efficient and environmentally friendly technique for denitrification treatment. The traditional biological denitrification technology has the limitations of large aeration energy consumption, insufficient carbon source, large alkalinity consumption, complex flow, poor ammonia nitrogen impact load resistance and the like. Compared with the traditional biological denitrification technology, the anaerobic ammonia oxidation biological denitrification technology has the advantages of small occupied area and high nitrogen load, and can save 62.5 percent of oxygen, 50 percent of alkalinity and 100 percent of carbon source. Due to the unique advantage in the aspect of economy, the biological denitrification device becomes a hot point of domestic and foreign research in recent years, and is the leading edge of the development of the biological denitrification technology of sewage in the future. However, the anaerobic ammonium oxidation bacteria have long multiplication time and long starting time and are easily influenced by various adverse factors to cause activity reduction, so that the method still has the main problem of restricting the wide application of the technology at present.

The forming mechanism of the granular sludge is mainly due to the external selective pressure effect, such as the short settling time, the high hydraulic shearing and the like, so that the microorganisms secrete more extracellular polymers with flocculation and adhesion effects, the microbial cells are mutually and tightly aggregated and arranged, the floc sludge structure is promoted to be more compact, and the floc sludge gradually becomes a regular spherical granular aggregate under the action of air-water combined flushing. The granular sludge is a spherical aggregate with higher density, is usually regarded as a special biological membrane, has the characteristics of biological compactness, high relative density, high settling speed and the like, and can keep higher sludge concentration and volume load in a reactor. And the granular sludge can bear the impact of pollutants and toxic substances with higher concentration, and the granular sludge has many advantages, so that if the anaerobic ammonia oxidizing bacteria are cultured into the granular sludge, the impact resistance of the anaerobic ammonia oxidizing bacteria can be greatly improved, and the volume load can be further improved. However, the granular sludge is formed for a long time, the proliferation rate of the anammox bacteria is slow, and how to promote the rapid granulation of the anammox bacteria becomes important, and the method for promoting the rapid granulation of the anammox bacteria by using the coagulant solves the problem.

Disclosure of Invention

The invention aims to promote anaerobic ammonium oxidation bacteria to rapidly granulate into granular sludge by using a coagulant.

In order to achieve the purpose, the technical scheme provided by the invention is as follows:

a method for promoting rapid granulation of anaerobic ammonium oxidation bacteria by using a coagulant specifically comprises the following steps:

the first step is as follows: the biological pond is operated in a sequencing batch mode, and the operation process comprises water feeding, stirring, standing and water discharging;

preparing 30g PAC/L aqueous solution, determining the specific concentration of extracellular polymeric substance protein of the microbial aggregate at the moment to be 20mg/g MLVSS, determining the Zata potential value to be-21 mV, and determining the ratio of the volume of 30g PAC/L coagulant to the volume of the pool volume to be 1: adding 80-100 of the adding amount into a biological pond to promote the secretion of extracellular proteins, gradually increasing the specific concentration of the extracellular polymeric proteins to 80mg/gMLVSS, and increasing the Zata potential value to-15 mV to ensure that microorganisms can form aggregates;

when the sedimentation time of the biological pond is shortened to 10min, the water begins to be drained, and the drainage ratio is 40-60%;

the hydraulic shear rate of the biological pond is improved by 10s^-1；

After elutriation and selection actions of sedimentation selective pressure and hydraulic shearing selective pressure, a large amount of extracellular proteins are secreted by the intercepted microorganisms to reduce the electronegativity of the microorganisms, and the microorganisms are flocculated again under the action of PAC to form a microorganism aggregate with the PAC as a framework, meanwhile, a flocculation phenomenon similar to 'net catching rolling sweeping' appears around an aggregate inner core due to a large amount of added PAC, and the newly formed microorganism aggregate gradually becomes compact under the scouring action of hydraulic shearing force and is compressed to be spherical under the adhesion action of PAC to form an aggregate which is obviously observed in a fine particle state by naked eyes;

the second step is as follows: after forming visible particles, the volume ratio of 30gPAC/L coagulant to the tank volume of 1: adding the 120-140 adding amount into a biological pond, and maintaining the specific concentration of the extracellular polymeric protein of the microbial aggregate at 140mg/gMLVSS and the potential value of Zata at-10 mV; PAC flocculation, sedimentation selective pressure and hydraulic shearing selective pressure are simultaneously used; the concentration limit of the influent substrate is set to stabilize the granular sludge to be more than 0.45mm in particle size, so that the mature granular sludge is obtained.

Compared with the prior art, the invention has the following characteristics and beneficial effects:

1. can quickly realize granulation of the anaerobic ammonium oxidation bacteria, enhances the sedimentation performance of the anaerobic ammonium oxidation bacteria and is not easy to run off. The impact resistance and the poison resistance of the anammox bacteria are enhanced, and the stability of the anammox process is improved. The increase of the biomass of the anaerobic ammonium oxidation strain has high load, less land occupation and low investment cost.

2. The anaerobic ammonia oxidation bacteria can secrete extracellular protein to form granulated sludge for at least 3-6 months, the rapid granulation of the anaerobic ammonia oxidation bacteria is realized by adding the coagulant, the macroscopic, dense and good-settling-property granulated sludge can be formed in 2 weeks-1 month, and a large amount of time is saved.

3. The coagulant is cheap, simple and easy to obtain, and the cost of the granulation starting process is low.

4. The method is practical, simple in process, free of secondary pollution and simple, convenient and reliable in operation of the granulation starting process.

Drawings

FIG. 1 shows the mechanism of the granulation of anammox bacteria by self-secreted extracellular proteins

FIG. 2 is a mechanism of coagulant promoting rapid granulation of anammox

FIG. 3 is a photograph of anammox fine particle sludge

FIG. 4 is a photograph of anammox matured granular sludge

Detailed Description

A method for promoting rapid granulation of anaerobic ammonium oxidation bacteria by using a coagulant specifically comprises the following steps:

the first step is that the operation mode of the biological pond is sequential batch operation, and the operation process comprises water feeding, stirring, standing and water discharging. The technology for promoting the rapid granulation of the anaerobic ammonia oxidation by the coagulant is characterized in that the rapid granulation is realized by adopting proper coagulant adding amount at different granulation stages and controlling the protein specific concentration and the Zata potential value of the microbial aggregate extracellular polymeric substance at different granulation stages. The addition of the coagulant promotes the secretion speed of extracellular protein, and the coagulant contains extracellular protein, such as microbial coagulant and the like, and the increase of the extracellular protein enhances the coagulability of the microbes, so that the microbes are aggregated and adhered. On the other hand, the coagulant and the extracellular protein can increase the Zata potential, according to the DLVO theory, the Zeta potential is one of the decisive factors for determining whether effective collision can occur between particles to cause mutual aggregation, generally, the surfaces of microorganisms have a large amount of negative charges, cells are difficult to aggregate to form larger aggregates due to the action of electrostatic repulsion, and the positively charged extracellular protein can reduce the surface charges of the microorganisms, so that the microorganisms can aggregate to each other.

A common coagulant, such as polyaluminium chloride (PAC), is purchased from the market to prepare 30gPAC/L aqueous solution, the specific concentration of extracellular polymeric protein of the microbial aggregate is measured to be 20mg/gMLVSS, the Zata potential value is measured to be-21 mV, and the volume ratio of the 30gPAC/L coagulant to the pool volume is 1: adding 80-100 of coagulant PAC into the biological pond to promote the secretion of extracellular protein, gradually increasing the specific concentration of extracellular polymer protein to about 80mg/gMLVSS, and the PAC has positive charge to offset the negative charge on the surface of the microorganism, and increasing the Zata potential value to about-15 mV to enable the microorganism to form an aggregate.

Meanwhile, the biological pond starts to discharge water when the sedimentation time is shortened to 10min, the drainage ratio is 40-60%, the sedimentation selective pressure effect is improved, microorganisms secrete more extracellular proteins to reduce the surface charge Zeta potential of the microorganisms in order to resist the sedimentation selective pressure, and the added coagulant promotes the microorganisms to secrete the extracellular proteins so as to play a role in reducing the Zeta potential. When the Zeta potential is reduced, the small microbial aggregates can be effectively collided and flocculated to form larger aggregates. The microorganism morphology can be changed gradually, the microorganism is flocculated and adhered to be larger by small aggregates, and simultaneously, some inactivated floc can not be precipitated and discharged along with the discharged water.

Although the microbial aggregate forms larger floc under the action of extracellular polymer and can resist precipitation selective pressure, the structure of the aggregate is still loose and not compact enough, and the hydraulic shear rate of the biological tank is improved by 10s^-1In order to resist the scouring of the hydraulic shearing force in the reactor, the adhesion effect of the coagulant can gather and strain loose microorganism aggregates to gradually form compact microorganism aggregates similar to spheres.

After elutriation and selection actions of the sedimentation selective pressure and the hydraulic shearing selective pressure, a large amount of extracellular proteins are secreted by the entrapped microorganisms to reduce the electronegativity of the microorganisms, the microorganisms are flocculated again under the action of PAC to form a PAC skeleton microbial aggregate, meanwhile, a flocculation phenomenon similar to net catching and sweeping appears around the inner core of the aggregate by adding a large amount of PAC, the newly formed microbial aggregate is gradually compacted and compressed to be spherical under the scouring action of hydraulic shearing force by virtue of the adhesion action of PAC, and the obvious fine particle state aggregate can be observed by naked eyes within about 2 weeks, and the mean particle size of the anaerobic ammonia oxidation particles is 0.15mm (see figure 3 in example 1).

The second step is that after visible particles are formed, the volume ratio of the cell volume to the volume of the coagulant is 30gPAC/L per day according to the following ratio of 1: the addition amount of 120-140-fold sand is added into the biological pond, the specific concentration of extracellular polymeric protein of the microbial aggregate is maintained to be about 140mg/gMLVSS, the Zata potential value is about-10 mV, the microorganisms are continuously propagated and increased due to the continuous addition of the water inlet substrate, and meanwhile, under the multiple actions of PAC flocculation, precipitation selective pressure and hydraulic shearing selective pressure, the particle size is gradually increased, the sphericity coefficient of the particle form is gradually improved, the particles are more and more compact, and the sedimentation performance is better and better. Finally, the granular sludge is stabilized in a particle size form of more than 0.45mm due to the inlet water substrate concentration limit value, and becomes mature granular sludge (see figure 4 in example 1 for an effect graph).

The traditional granulated sludge culture mode only depends on the coagulation effect of extracellular protein secreted by microorganisms to form granules, and generally needs more than 3-6 months. In contrast, the method for promoting granulation by controlling the specific concentration of the extracellular polymeric protein of the microbial aggregate and the Zata potential value at different stages by using the exogenous coagulant can effectively shorten the time required by the granulation process and control the time within 2 weeks to 1 month.

The following further describes the embodiment of the present invention with reference to fig. 1, fig. 2, fig. 3 and fig. 4.

A certain sludge treatment plant adopts a two-stage nitrosation-anaerobic ammonia oxidation process to treat sludge biogas slurry, one nitrosation tank is matched with twoThe anaerobic ammonia oxidation tank and the nitrosation biological tank have the volume of 1100m³The anaerobic ammonium oxidation biological tank A (called an anaerobic A tank for short) has a tank capacity of 400m³The tank capacity of an anaerobic ammonia oxidation biological tank B (called an anaerobic tank B for short) is 400m³The operation modes are all sequencing batch operation. In order to improve the process throughput and enhance the operation stability of the anaerobic ammonia oxidation process, anaerobic ammonia oxidation bacteria need to be cultured into granular bacteria.

And taking the anaerobic ammonia A tank as a blank group, and observing the granulation effect without adding a coagulant. And the anaerobic ammonia B tank is used as an experimental group, and polyaluminium chloride (PAC) is added to promote the rapid granulation of the anaerobic ammonia oxidizing bacteria and accelerate the granulation process of the anaerobic ammonia oxidizing bacteria. Polyaluminum chloride pale yellow powder with 30% (M/M) of effective aluminum content is purchased from the market and prepared into 30gPAC/L aqueous solution.

Example 1

The specific concentration of the microbial aggregate extracellular polymeric proteins in the anaerobic A tank at the initial granulation stage is 21mg/gMLVSS, the Zata potential value is-20 mV, the settling time of the anaerobic A tank is shortened to 10min, and the hydraulic shear rate is maintained at 10s^-1After adjusting the settling time and the hydraulic shear rate, the light dispersion is elutriated out of the reactor under the action of the settling selective pressure and the hydraulic shear selective pressure, and the heavier anammox bacteria are selectively trapped. After elutriation and selection actions of precipitation selective pressure and hydraulic shearing selective pressure, the intercepted anaerobic ammonia oxidizing bacteria secrete a large amount of extracellular proteins so as to reduce the electronegativity of the anaerobic ammonia oxidizing bacteria, the specific concentration of the extracellular polymeric proteins of the anaerobic A pool microbial aggregate is increased to 42mg/gMLVSS, and the Zata potential value is increased to-17 mV. On day 96, visually, distinct aggregates in the fine particle state (see FIG. 3) were observed, with a mean particle size of 0.15 mm.

And (3) after the anaerobic A pool forms visible particles, continuing to operate, wherein the specific concentration of the extracellular polymeric protein of the microbial aggregate in the anaerobic A pool is increased to 85mg/gMLVSS, and the Zata potential value is increased to-13 mV. Because the matrix of intaking constantly adds for anaerobic ammonium oxidation fungus breeds more constantly, and under the multiple effect of sediment selective pressure, hydraulic shear selective pressure simultaneously, granule particle diameter grow gradually, and granule form sphericity coefficient improves gradually, and the granule is more and more closely knit, and settling properties is more and more good. After 168 days of stable operation, the average particle size of the granular sludge is 0.45mm, and the mature granular sludge is formed (as shown in figure 4).

Example 2

The specific concentration of the microbial aggregate extracellular polymeric protein in the anaerobic B tank at the initial granulation stage is 20mg/gMLVSS, the Zata potential value is-21 mV, and the volume ratio of the anaerobic B tank to the tank volume is 1: 80 addition amount is 5m³Adding a coagulant into an anaerobic B tank, similarly shortening the settling time to 10min, and maintaining the hydraulic shear rate at 10s^-1. After the coagulant is added into the anaerobic tank B, the flocs in the biological tank are immediately disintegrated, the phenomenon similar to colloid destabilization is obvious, the original floc structure is broken, and smaller dispersoids are presented. After adjusting the settling time and the hydraulic shear rate, the light dispersion is elutriated out of the reactor under the action of the settling selective pressure and the hydraulic shear selective pressure, and the heavier anammox bacteria are selectively trapped. After elutriation and selection actions of precipitation selective pressure and hydraulic shearing selective pressure, the intercepted anaerobic ammonium oxidation bacteria secrete a large amount of extracellular proteins so as to reduce the electronegativity of the anaerobic ammonium oxidation bacteria. The specific concentration of the anaerobic B pool microbial aggregate extracellular polymeric protein is increased to 83mg/gMLVSS, the Zata potential value is increased to-14 mV, and the anaerobic ammonia oxidizing bacteria aggregate with PAC as a framework is formed by re-flocculation under the action of PAC. At the same time, the large amount of PAC added caused flocculation around the aggregate cores similar to "net-roll sweeping". The newly-appeared viscous floc can intercept and adhere more anammox bacteria, and the newly-formed anammox bacteria aggregate gradually becomes compact and is compressed into a sphere under the action of hydraulic shear force and the adhesion of PAC. On day 15, visible aggregates in the form of fine particles were observed with the naked eye, with an average particle size of up to 0.15mm (for an effect picture see fig. 3 in example 1).

After visible particles are formed in the anaerobic B tank, the specific concentration of extracellular polymeric protein of the microbial aggregate is maintained to be 140mg/gMLVSS, the Zata potential is-10 mV, and the volume ratio of the tank volume to the tank volume is 1: 120 adding amount is added into the biological pond, and as the water inlet substrate is continuously added, the anaerobic ammonium oxidation bacteria are continuously propagated and increased, and simultaneously under the multiple actions of PAC flocculation, sedimentation selective pressure and hydraulic shearing selective pressure. The particle size of the particles is gradually increased, the sphericity coefficient of the particle morphology is gradually improved, the particles are more and more compact, and the sedimentation performance is more and more good. After 32 days of stable operation, the average particle size of the granular sludge reaches 0.45mm, and the granular sludge becomes mature granular sludge (see figure 4 in example 1).

Comparative analysis

Comparison of example 1 with example 2 shows that:

in the granulation forming stage, the anaerobic B tank is arranged according to the volume ratio of 30gPAC/L coagulant to 1: 80, the specific concentration of extracellular polymeric protein of the microbial aggregate in the anaerobic B tank is increased to 83mg/gMLVSS, the Zata potential value is increased to-14 mV, obvious aggregates in a fine particle state can be observed by naked eyes after 15 days, the average particle size of particles reaches 0.15mm, the aggregate in the anaerobic A tank reaches 96 days, and the process of forming granular bacteria is greatly accelerated by adding the coagulant. In the granulation and maturation stage, the anaerobic tank B is characterized in that the volume ratio of 30gPAC/L coagulant to the tank volume is 1: the addition amount of 120 is increased, the specific concentration of the extracellular polymeric protein of the microbial aggregate in the anaerobic B tank is increased to 140mg/gMLVSS, the Zata potential is increased to-10 mV, the average particle size of the granular sludge reaches 0.45mm only in 32 days to become mature granular sludge, and the average particle size of the granular sludge reaches 168 days to reach the anaerobic A tank, so that the addition of the coagulant greatly accelerates the maturation process of granular bacteria. The embodiment shows that the protein specific concentration and the Zata potential value of the microbial aggregate extracellular polymeric substance can be controlled to realize rapid granulation by adopting the proper coagulant adding amount in different granulation stages.