CN106830300A - It is a kind of to nurse one's health the method that returned sludge rapidly promotes aerobic sludge granulation by adding iron ion - Google Patents

Abstract

A kind of to nurse one's health the method that returned sludge rapidly promotes aerobic sludge granulation by adding iron ion, methods described comprises the following steps：1) take using the reactor of Sewage Treatment for Activated Sludge, reactor is normally running；2) excess sludge of discharge is collected, by 10 500mg (Fe³⁺The content addition iron ion of)/g (MLSS), it is 50% 70% to dry in the shade to moisture content, prepares target sludge；3) using step 2) in prepared target sludge put into former reactor as returned sludge and normally run；4) repeat step 3) and step 4), until aerobic sludge basic granulesization and stable operation in reactor.The present invention is using discarded excess sludge; as returned sludge Returning reactor after adding iron ion, desiccation conditioning; it is artificial to create biofeedback mechanism, using iron chelate, micropopulation sense effect and cell signaling molecule, provide the granulating that nuclei of condensation etc. collectively promote aerobic sludge.

Description

A rapid promotion of aerobic sludge granulation by conditioning return sludge by adding iron ions Methods

technical field

The invention belongs to the field of sludge treatment, and relates to a method for rapidly promoting aerobic sludge granulation by adding iron ions to condition return sludge.

technical background

Compared with ordinary activated sludge, aerobic granular sludge technology has good settling performance, high sludge concentration, and can withstand high organic load, load shock and toxic substances, etc., and it is becoming a hot research and report from all walks of life. Generally speaking, the formation of aerobic granular sludge is a complex process involving physical, chemical and biological effects. The mainstream view describes this process as a phenomenon of biological aggregation formed by microbial self-agglomeration under certain hydrodynamic conditions. . Scholars at home and abroad have proposed various aerobic granular sludge formation mechanisms based on their own experimental research based on different reactors, experimental methods, and research purposes. At present, the mainstream mechanism of aerobic granular sludge formation mainly includes extracellular polymer hypothesis, self-aggregation principle, filamentous bacteria hypothesis and condensation nucleus mechanism. The latest research shows that the signal exchange between microorganisms also plays an important role in the process of aerobic sludge granulation.

The mechanism of condensation nuclei is that the formation of aerobic granular sludge must first have a condensation nuclei to provide a place for the aggregation and growth of microorganisms, such as suspended particles, inoculated anaerobic or aerobic granular sludge, and biofilm formed on the reactor wall , larger filamentous bacteria, etc. Small inorganic particles in water will have a small amount of positive charge under the action of hydraulic shear force, and will absorb a certain amount of bacteria and other negatively charged microorganisms: Small organic particles in water will secrete extracellular polymerization under the action of hydraulic shear force It can improve the hydrophobicity of the cell surface, reduce the Gibbs free energy of the cell surface, and provide favorable conditions for the interaction and adhesion between cells. Control a certain settling time, settling depth and other working conditions in the reactor to create a certain selective pressure, and keep the larger particles in the reactor, so that the condensation nuclei and the microorganisms adhering to it have sufficient time and nutrients to grow. And further adhere to more microorganisms to form irregular sludge particles, that is, embryonic particle sludge. Embryo granular sludge gradually forms aerobic granular sludge with regular shape and vertical three-dimensional structure under the action of hydraulic shear force. When the particle reaches a certain size, the particle size stops due to the limitation of oxygen mass transfer and matrix mass transfer. Growth, the aerobic granular sludge formed at this time is mature aerobic granular sludge. As an indispensable trace element for microbial growth, iron ions have been shown to promote aerobic sludge granulation. Iron ions can form unique chelates to attract microorganisms to attach and fix. Existing studies have promoted aerobic sludge granulation by adding activated carbon, diatomite, magnetic powder, micropowder, etc. as condensation nuclei inside the reactor, but the overall effect of adding activated carbon, diatomaceous earth, magnetic powder, micropowder, etc. It is not very ideal, and it is not conducive to mass addition and cost control in engineering applications. It is a technical measure adopted by many sewage treatment processes to return part of the excess sludge to the reactor as return sludge, but there are few reports on the promotion of aerobic sludge granulation by conditioning the return sludge outside the reactor. At the same time, studies have shown that aerobic sludge will produce a detailed group-sensing effect during granulation, and related cell signaling molecules play an important role in it. The group-sensing effect can accelerate the synthesis of sludge extracellular polymers and improve the ability of microorganisms to adhere to the surface , signal molecules can promote the secretion of extracellular polymers by microorganisms and affect the formation of biofilms, such as the increase of c-di-GMP signal molecules can promote the formation of aerobic granular sludge.

Contents of the invention

In order to overcome the current problems of long period of aerobic granular sludge cultivation, easy instability, lack of biofeedback mechanism, etc., the present invention provides a simple, economical and efficient way to quickly promote aerobic sludge granulation by adding iron ions to condition the return sludge. method of transformation.

In order to solve the aforementioned problems, the following technical solutions are provided:

A method for rapidly promoting aerobic sludge granulation by adding iron ions to condition return sludge, comprising the following steps:

1) Take the reactor that utilizes activated sludge to treat sewage, and the reactor is in normal operation;

2) Collect the discharged excess sludge, add iron ions according to the content of 10-500mg(Fe ³⁺ )/g(MLSS), dry in the shade until the water content is 50%-70%, and prepare the target sludge;

3) put the target sludge prepared in step 2) into the original reactor as return sludge and operate normally;

4) Step 3) and step 4) are repeated until the aerobic sludge in the reactor is basically granulated and operates stably.

The technical idea of the present invention is: the present invention combines the microbial swarm sensing effect and cell signal molecular science, and uses the lighter excess sludge selected to be discharged from the reactor as the return sludge after conditioning and treatment means such as adding iron ions and proper drying. The sludge is returned to the reactor to form a biofeedback mechanism that promotes the aggregation and granulation of the microorganisms in the reactor; the external addition of iron ions is used to stimulate the microorganisms to release a large amount of extracellular polymers as binders, so that the processed Sludge has the characteristics of a large number of lumps or flocs and other biological aggregates. After returning to the reactor, a large number of fine particles are formed due to external forces such as hydraulic power and aeration. The mechanism of condensation nuclei is used to provide a certain degree of coagulation for the granulation of aerobic sludge. Nucleate and accelerate the formation of aerobic granular sludge; at the same time, use iron ions to generate positively charged chelates, actively adsorb negatively charged microorganisms, strengthen the formation of biopolymers, and promote the formation of aerobic granular sludge; The remaining sludge comes from the reactor, and the microorganisms are from the same source without foreign organisms, and will not cause biological invasion to the microorganisms in the reactor. The sludge dried in the shade to a moisture content of 50%-70% can maintain microbial activity to form biofeedback, and can also form condensation nuclei by self-coagulation or agglomeration under the action of iron elements, ensuring the realization of the aforementioned mechanism. At the same time, the remaining sludge will be treated as resources to obtain certain economic benefits.

The beneficial effects of the present invention are mainly reflected in:

(1) Using the microbial quorum sensing effect and cell signaling molecules, artificially create a biofeedback mechanism to promote the accumulation and granulation of aerobic sludge.

(2) Use iron ions to condition the excess sludge, stimulate it to produce a large amount of extracellular polymers, etc. as binders, strengthen the agglomeration of excess sludge into lumps or blocks, and produce a large amount of sludge under the action of external force after being thrown back into the reactor. Fine particles that provide condensation nuclei for the formation of aerobic granular sludge.

(3) Use iron ions to generate positively charged chelates, actively adsorb negatively charged microorganisms, strengthen the formation of biopolymers, and promote the formation of aerobic granular sludge.

(4) No exogenous organisms are added, which will not cause biological invasion and affect the drastic changes of the bacterial species in the reactor.

(5) Recycling of waste, using excess sludge for resource treatment, reducing the amount of sludge produced.

(6) Greatly shorten the cultivation time of aerobic granular sludge.

(7) The operation is simple, only iron ions need to be added and properly dried, the process is simple, iron ions are relatively common and easy to obtain, the method has strong operability, low cost, and easy engineering application.

(8) Compared with ordinary activated sludge, aerobic granular sludge prepared by induction has the advantages of compactness, high treatment efficiency, good settling performance, and strong impact load resistance.

detailed description

The present invention will be further described below in conjunction with specific examples, but the protection scope of the present invention is not limited thereto.

Example 1

A method for rapidly promoting aerobic sludge granulation by adding iron ions to condition return sludge, comprising the following steps:

1) Take the reactor in normal operation, the influent COD concentration is 500mg/L, the NH ₄ ⁺ -N concentration is 25mg/L, and the TP concentration is 5mg/L; the reactor adopts the SBR method, and the main operating parameters are set to stand The time is 1h, the aeration time is 3h; the amount of activated sludge in the reactor is 3000mg/L.

2) Collect the discharged excess sludge, add ferric chloride according to the content of 500 mg (Fe ³⁺ )/g (MLSS), and dry in the shade until the water content is 50%, to prepare the target sludge.

3) The target sludge prepared in step 3) was put into the original reactor as return sludge and operated normally. Under the action of hydraulic force, a large amount of blocky or agglomerated sludge of different sizes appeared in the reactor.

5) Repeat step 3) and step 4) once a day. After 4 days of operation, the granulation in the reactor reaches 92%, the SVI of the granular sludge is less than 43ml/g, and the settling performance is good.

The granular sludge formed by using the excess sludge feedback mechanism in the present invention has the advantages of compactness, high treatment efficiency, and good settling performance. The removal rate of COD is about 99%, the removal rate of ammonia nitrogen is basically maintained at about 99%, the sedimentation velocity is 20-30m/h, and the sludge volume index (SVI) drops from 80ml/g of inoculated sludge to below 43ml/g. MLSS increased to 6400mg/L.

Example 2

A method for rapidly promoting aerobic sludge granulation by adding iron ions to condition return sludge, comprising the following steps:

1) Take the reactor in normal operation, the influent COD concentration is 500mg/L, the NH ₄ ⁺ -N concentration is 25mg/L, and the TP concentration is 5mg/L; the reactor adopts the SBR method, and the main operating parameters are set to stand The time is 1h, the aeration time is 3h; the amount of activated sludge in the reactor is 2000mg/L.

2) Collect the discharged excess sludge, add ferric chloride according to the content of 300 mg (Fe ³⁺ )/g (MLSS), and dry in the shade until the water content is 60%, to prepare the target sludge.

3) The target sludge prepared in step 3) was put into the original reactor as return sludge and operated normally. Under the action of hydraulic force, a large amount of blocky or agglomerated sludge of different sizes appeared in the reactor.

5) Step 3) and step 4) were repeated once a day, and after 4 days of operation, the granulation in the reactor reached 86%, the SVI of the granular sludge was less than 45ml/g, and the settling performance was good.

The granular sludge formed by using the excess sludge feedback mechanism in the present invention has the advantages of compactness, high treatment efficiency, and good settling performance. The removal rate of COD is about 98%, the removal rate of ammonia nitrogen is basically maintained at about 99%, the sedimentation velocity is 20-30m/h, and the sludge volume index (SVI) drops from 92ml/g of inoculated sludge to below 45ml/g. MLSS increased to 5600mg/L.

Example 3

A method for rapidly promoting aerobic sludge granulation by adding iron ions to condition return sludge, comprising the following steps:

1) Take the reactor in normal operation, the influent COD concentration is 500mg/L, the NH ₄ ⁺ -N concentration is 25mg/L, and the TP concentration is 5mg/L; the reactor adopts a joint-built oxidation ditch process, and the water retention time 10 hours; the amount of activated sludge in the reactor is 2500mg/L.

2) Collect the discharged excess sludge, add ferric chloride according to the content of 10 mg (Fe ³⁺ )/g (MLSS), and dry in the shade until the water content is 70%, to prepare the target sludge.

3) The target sludge prepared in step 3) was put into the original reactor as return sludge and operated normally. Under the action of hydraulic force, a large amount of blocky or agglomerated sludge of different sizes appeared in the reactor.

5) Repeat step 3) and step 4) once a day. After 7 days of operation, the granulation in the reactor reaches 85%, the SVI of the granular sludge is less than 48ml/g, and the sedimentation performance is good.

The granular sludge formed by using the excess sludge feedback mechanism in the present invention has the advantages of compactness, high treatment efficiency, and good settling performance. The removal rate of COD is about 95%, the removal rate of ammonia nitrogen is basically maintained at about 99%, the sedimentation velocity is 20-30m/h, and the sludge volume index (SVI) drops from 90ml/g of inoculated sludge to below 48ml/g. MLSS increased to 5400mg/L.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications, substitutions and variations can be made to the embodiments without departing from the principle and spirit of the present invention. The scope of the invention is defined by the claims and their equivalents.

Claims (1)

1. It is 1. a kind of to nurse one's health the method that returned sludge rapidly promotes aerobic sludge granulation by adding iron ion, it is characterised in that： Methods described comprises the following steps：

   1) take using the reactor of Sewage Treatment for Activated Sludge, reactor is normally running；

   2) excess sludge of discharge is collected, by 10-500mg (Fe³⁺The content addition iron ion of)/g (MLSS), dries in the shade to moisture content It is 50%-70%, prepares target sludge；

   3) using step 2) in prepared target sludge put into former reactor as returned sludge and normally run；

   4) repeat step 3) and step 4), until aerobic sludge basic granulesization and stable operation in reactor.