阅读说明：本技术 一种以产pha为导向的非甲烷化工艺 (Non-methanation process with PHA production as guide ) 是由 刘云洲 于 2021-01-07 设计创作，主要内容包括：本发明公开了一种以产PHA为导向的非甲烷化工艺,属于厌氧工艺资源回收领域。它包括SBR反应器、污泥收集器和带有总磷传感器的收集器,所述SBR反应器一侧的底部连通、进水管,所述SBR反应器一侧上还连通有二氧化碳进气口,所述SBR反应器的内部还设有曝气盘,所述SBR反应器的内部设有搅拌组件,用于对SBR反应器内部的物质进行搅拌作业,所述SBR反应器的另一侧底部连通有排泥管,所述SBR反应器的另一侧上还连通有出水管,所述排泥管另一端通过导管伸入污泥收集器的底部。本发明为缓解塑料带来的环境压力,实现资源的可持续发展,该发明提供的以PHA为导向的非甲烷工艺可以降低PHA生产成本,提高厌氧过程中PHA的产率。(The invention discloses a non-methanation process with PHA production as a guide, belonging to the field of anaerobic process resource recovery. It includes SBR reactor, sludge collector and has the collector of total phosphorus sensor, bottom intercommunication, the inlet tube of SBR reactor one side, it has the carbon dioxide air inlet still to communicate on SBR reactor one side, the inside of SBR reactor still is equipped with the aeration dish, the inside of SBR reactor is equipped with the stirring subassembly for stir the operation to the inside material of SBR reactor, the opposite side bottom intercommunication of SBR reactor has the sludge discharge pipe, it has the outlet pipe still to communicate on the opposite side of SBR reactor, the sludge discharge pipe other end stretches into sludge collector's bottom through the pipe. The method can relieve the environmental pressure brought by plastics and realize sustainable development of resources, and the PHA-oriented non-methane process provided by the invention can reduce the production cost of PHA and improve the yield of PHA in an anaerobic process.)

1. A non-methanation process directed towards PHA production comprising an SBR reactor (14), a sludge collector (12) and a collector with total phosphorus sensor (13), characterized in that: the bottom intercommunication, inlet tube (2) of SBR reactor (14) one side, it has carbon dioxide air inlet (1) still to communicate on SBR reactor (14) one side, the inside of SBR reactor (14) still is equipped with aeration dish (8), the inside of SBR reactor (14) is equipped with the stirring subassembly for stir the operation to the inside material of SBR reactor (14), the opposite side bottom intercommunication of SBR reactor (14) has mud pipe (5), it has outlet pipe (4) still to communicate on the opposite side of SBR reactor (14), the bottom that mud pipe (5) other end stretched into mud collector (12) through the pipe, mud collector (12) go up the intercommunication have one number dosing pipe (6), it has supernatant suction pump (7) still to communicate through the pipe on mud collector (12), supernatant suction pump (7) output is linked together through pipe and collector (13) that have total phosphorus sensor, one side of the collector (13) with the total phosphorus sensor is respectively communicated with a two-number dosing pipe (9) and an air inlet (10).

2. The non-methanation process as claimed in claim 1, wherein the non-methanation process is directed to PHA production: inlet tube (2) and carbon dioxide air inlet (1) all lie in the same one side of SBR reactor (14), mud pipe (5) and outlet pipe (4) lie in the same one side of SBR reactor (14).

3. The non-methanation process as claimed in claim 1, wherein the non-methanation process is directed to PHA production: the stirring subassembly includes motor and stirring rake (3), motor fixed end fixed mounting is at the top of SBR reactor, the top and the motor output of stirring rake (3) are fixed mutually, inside and fixedly connected with stirring vane of SBR reactor is stretched into to stirring rake (3) bottom.

4. The non-methanation process as claimed in claim 1, wherein the non-methanation process is directed to PHA production: an on-line COD sensor (11) is also arranged on the SBR reactor (14).

5. A non-methanation process method taking PHA production as a guide is characterized by comprising the following steps:

s1, enriching microorganisms;

gathering PHA-producing microorganisms by adopting a residual sludge anaerobic fermentation mode, and controlling the microbial reaction in an acid-producing stage by adjusting reaction conditions such as pH, temperature and the like; the domestication of the activated sludge flora adopts a filling-hungry mode, and enrichment is carried out under the micro-aerobic condition;

the excess sludge takes sewage as a carbon source, when microorganisms are enriched, a certain carbon source is firstly introduced in a short time, the microorganisms in the excess sludge absorb the carbon source in an anaerobic stage, and PHA is stored in the microorganisms producing PHA; then stopping adding the carbon source, and introducing air for a long time; at the moment, the carbon source of the system is not enough for the growth and metabolism of the flora, the non-PHA synthetic bacteria are eliminated because of no carbon source, and the PHA synthetic bacteria can utilize the stored PHA to continue to grow; the filling-starvation mode is utilized to naturally eliminate the non-PHA synthetic bacteria, so that the survival capacity of the PHA synthetic bacteria is enhanced;

s2, synthesis of PHA:

controlling the anaerobic process at an acid production stage, controlling the reaction temperature at 55 ℃ and the pH at 9.5-10.5, wherein the system utilizes organic matters in water to generate organic acid and hydrogen, and the generated organic acid is a main raw material for generating PHA; in the SBR (14), microorganisms firstly use organic acid as raw materials to generate PHA under anaerobic conditions, and part of PHA synthetic bacteria can utilize hydrogen as energy source and carbon dioxide as carbon source to synthesize PHA under aerobic conditions; therefore, the PHA synthesis can be carried out in an intermittent aeration mode in the reaction process; the SBR reactor (14) is provided with an online COD sensor (11) which is connected with a PCL system, and the PCL system controls an aeration device; the microorganism firstly synthesizes PHA by organic acid under anaerobic condition, when the content of COD in the system is less than 50 mg/L, the aeration device is opened, and PHA is synthesized by taking hydrogen and carbon dioxide as raw materials under micro-aeration state;

s3, PHA extraction:

switchable Anionic Surfactants (SAS), which is a secondary sodium alkyl sulfonate, are used to easily avoid unnecessary surfactant consumption when large doses are required in a particular process; the surfactant enters the lipid membrane and increases the volume of the cell membrane until rupture; then forming micelles of surfactant and membrane phospholipids and releasing PHA granules; surfactants may also solubilize proteins and other molecules from the non-polymeric cytoplasm (NPCM); and adding iron salt into the mixed liquid supernatant after SAS treatment, forming iron pyrite precipitate with phosphorus released by sludge crushing, and recovering the iron pyrite.

Technical Field

The invention relates to a non-methanation process with PHA production as a guide, belonging to the field of anaerobic process resource recovery.

Background

The increasing amount of plastics in the environment is one of the most relevant environmental issues facing mankind today, and in order to achieve sustainable development we need to develop new renewable energy sources. The environmental pressure imposed by plastics is relieved by the advent of bioplastics, which are bio-based polymers obtained from organic renewable resources, with little environmental impact, since most of them are completely biodegradable. Among them, Polyhydroxyalkanoates (PHAs) are a bio-based biodegradable polymer that can be produced from various complex organic substrates by bacterial fermentation. In this case, therefore, resource recovery in the wastewater treatment process can play a role in the recycling economy of plastics.

At present, the yield of PHA is low, the production cost is high, and the main production cost is derived from the PHA production and extraction technology. Most of the current PHA synthesis technologies are to inoculate pure strains on a carbon source culture medium, but some technologies can also replace the carbon source into a wastewater carbon source in order to save cost. In patent CN111394398A, "method for preparing PHA by fermenting high-salt molasses as raw material", high-salt molasses is used as carbon source, pure PHA-synthesizing bacteria are inoculated, and the process uses industrial production waste as raw material, so that production cost is saved. However, the culture cost of the inoculated pure strains is too high, and the tolerance of the inoculum to pollutants in sewage is not high because the inoculum takes a pure carbon source (pure glucose or pure glycerol) as a raw material in the culture process.

The PHA extraction technology mainly comprises solvent extraction, supercritical fluid extraction, mechanical destruction and the like, although solution extraction can effectively extract PHA, certain extracting agents can influence the natural form of PHA particles, and are expensive and toxic to human health or environment. Supercritical fluids have the diffusion properties of gases and the solvating power of liquids, so they can diffuse through solids and dissolve materials. Extractants are still needed to recover the polymer and have not been widely used. Mechanical disruption is the physical disruption of microbial cell membranes to release intracellular PHA, but microbial cells are still pretreated.

Therefore, it is a problem to be researched to find a low-cost method for efficiently synthesizing PHA.

Disclosure of Invention

The invention aims at the technical problems mentioned in the background technology and is realized by adopting the following technical scheme, particularly, in order to relieve the environmental pressure brought by plastics and realize the sustainable development of resources, the PHA-oriented non-methane process provided by the invention can reduce the production cost of PHA and improve the yield of PHA in the anaerobic process.

A non-methanation process with PHA production as a guide comprises an SBR reactor, a sludge collector and a collector with a total phosphorus sensor, wherein the bottom of one side of the SBR reactor is communicated with a water inlet pipe, one side of the SBR reactor is communicated with a carbon dioxide air inlet, an aeration disc is further arranged in the SBR reactor, a stirring component is arranged in the SBR reactor and used for stirring the substances in the SBR reactor, the bottom of the other side of the SBR reactor is communicated with a sludge discharge pipe, the other side of the SBR reactor is communicated with a water outlet pipe, the other end of the sludge discharge pipe extends into the bottom of the sludge collector through a guide pipe, the sludge collector is communicated with a No. one chemical feeding pipe, the sludge collector is communicated with a supernatant water suction pump through a guide pipe, the output end of the supernatant water suction pump is communicated with the collector with the total phosphorus sensor through a guide pipe, and a two-type dosing pipe and an air inlet are respectively communicated with one side of the collector with the total phosphorus sensor.

As a preferred example, the water inlet pipe and the carbon dioxide gas inlet are both positioned on the same side of the SBR reactor, and the sludge discharge pipe and the water outlet pipe are positioned on the same side of the SBR reactor.

As a preferable example, the stirring assembly comprises a motor and a stirring paddle, wherein the fixed end of the motor is fixedly arranged at the top of the SBR reactor, the top of the stirring paddle is fixed with the output end of the motor, and the bottom end of the stirring paddle extends into the SBR reactor and is fixedly connected with a stirring blade.

As a preferred example, the SBR reactor is also provided with an on-line COD sensor.

A non-methanation process oriented to PHA production comprises the following steps:

s1, enriching microorganisms;

s2, synthesizing PHA;

s3, extracting PHA.

As a preferable example, in S1, PHA-producing microorganisms are enriched by anaerobic fermentation of excess sludge, and the microbial reaction is controlled in an acid-producing stage by adjusting reaction conditions such as pH and temperature; the domestication of the activated sludge flora adopts a filling-hungry mode and enrichment is carried out under the micro-aerobic condition.

As a preferred example, the excess sludge takes sewage as a carbon source, when microorganisms are enriched, a certain carbon source is firstly introduced in a short time, the microorganisms in the excess sludge absorb the carbon source in an anaerobic stage, and PHA is stored in the PHA-producing microorganisms; then stopping adding the carbon source, and introducing air for a long time; at the moment, the carbon source of the system is not enough for the growth and metabolism of the flora, the non-PHA synthetic bacteria are eliminated because of no carbon source, and the PHA synthetic bacteria can utilize the stored PHA to continue to grow; the filling-starvation mode is utilized to naturally eliminate the non-PHA synthetic bacteria, so that the survival capability of the PHA synthetic bacteria is enhanced.

It should be noted that: because the microorganisms in the excess sludge are the products of sewage treatment and have very good tolerance capacity to pollutants in the sewage, the excess sludge is utilized to enrich PHA-producing strains, so that the PHA-synthesizing cost can be saved on one hand, and the enriched microorganisms can have good organic matter removing effect when being directly used for removing organic matters in the sewage on the other hand.

As a preferred example, in S2, the anaerobic process is controlled in the acid production stage, the reaction temperature is controlled at 55 ℃, the pH is controlled at 9.5-10.5, the system utilizes the organic matters in the water to produce organic acid and hydrogen, and the produced organic acid is the main raw material for producing PHA; in the SBR reactor, microorganisms firstly use organic acid as raw materials to generate PHA under anaerobic conditions, and because part of PHA synthesis bacteria can utilize hydrogen as energy source and carbon dioxide as carbon source to synthesize PHA under aerobic conditions; therefore, the PHA synthesis can be carried out in an intermittent aeration mode in the reaction process; the SBR reactor is provided with an online COD sensor which is connected with a PCL system, and the PCL system controls an aeration device; the microorganism firstly synthesizes PHA by organic acid under anaerobic condition, when the COD content in the system is less than 50 mg/L, the aeration device is opened, and PHA synthesis is carried out by taking hydrogen and carbon dioxide as raw materials under the micro-aeration state.

It is to be noted that; as the phosphorus accumulating bacteria (PAOs) are typical dominant bacteria for synthesizing PHA, the sewage can be treated by combining phosphorus removal and PHA synthesis. Phosphorus is fixed in the sludge in an anaerobic-aerobic state, and the removal rate of the phosphorus can also be improved.

As a preferred example, in S3, a Switchable Anionic Surfactant (SAS) is used, which is a secondary sodium alkyl sulfonate, easily avoiding unnecessary surfactant consumption when large doses are required in a particular process; the surfactant enters the lipid membrane and increases the volume of the cell membrane until rupture; then forming micelles of surfactant and membrane phospholipids and releasing PHA granules; surfactants may also solubilize proteins and other molecules from the non-polymeric cytoplasm (NPCM); and adding iron salt into the mixed liquid supernatant after SAS treatment, forming iron pyrite precipitate with phosphorus released by sludge crushing, and recovering the iron pyrite.

It should be noted that: SAS represents a special class of surfactants that can be reversibly converted from a water-insoluble neutral form to an anionic water-soluble compound by pH change. The pH change can be achieved in a number of ways, but the addition and removal of carbon dioxide is the simplest and most efficient way in which they can be directly and reversibly converted to the least soluble form in the reaction medium so that they can be removed, recovered from the liquid phase and recycled. Therefore, after the recovery of vivianite, carbon dioxide (from advanced oxidation or advanced treatment) is introduced into the supernatant to change the water solubility of SAS, and insoluble SAS is recovered and can be recycled for PHA extraction.

The invention has the beneficial effects that:

(1) the excess sludge is adopted to enrich and domesticate microorganisms to synthesize PHA, so that the accumulation rate of PHA can be effectively improved;

(2) the sewage is used as a carbon source, PHA-producing microorganisms are enriched in a filling-starvation mode, non-PHA-producing microorganisms are naturally eliminated, and the adaptability of the PHA-producing microorganisms is improved;

(3) the PHA is generated from the dephosphorization combination, the dephosphorization efficiency of the system is improved, and the vivianite can be recovered.

(4) Organic matters in the sewage, hydrogen and carbon dioxide generated by reaction are used as substrates, and an external carbon source is not needed, so that the synthesis cost of PHA is reduced;

(4) the reaction is carried out in a micro-aeration-anaerobic mode, so that certain microorganisms can utilize hydrogen and carbon dioxide generated in the sewage treatment process as substrates to carry out PHA synthesis, and the emission of the carbon dioxide is reduced;

(6) the surfactant is adopted to destroy the cell matrix, so that a good treatment effect can be achieved, and meanwhile, the SAS can not generate subsequent pollution and is a green convertible substance;

(7) carbon dioxide is introduced into the supernatant after PHA and vivianite are recovered to recover SAS, so that SAS can be recycled.

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

In the figure: 1-carbon dioxide inlet, 2-inlet pipe, 3-stirring paddle, 4-outlet pipe, 5-sludge discharge pipe, 6-I dosing pipe, 7-supernatant water pump, 8-aeration disc, 9-II dosing pipe, 10-inlet, 11-online COD sensor, 12-sludge collector, 13-collector with total phosphorus sensor, and SBR reactor 14.

Detailed Description

In order to make the technical means, the original characteristics, the achieved purpose and the efficacy of the invention easily understood, the invention is further described with reference to the following embodiments.

Examples

Taking excess sludge of a sewage treatment plant for enrichment culture of microorganisms, and controlling the reaction in an acid-producing and hydrogen-producing stage by controlling the reaction conditions (pH is 10 and temperature is 55 ℃); an anaerobic-aerobic process is adopted, microorganisms introduce a carbon source in an anaerobic stage, the carbon source is ingested to store PHA in vivo, and when air is introduced in a subsequent aerobic stage, the carbon source of the system is insufficient for the growth and metabolism of flora, and PHA synthetic bacteria can continue to grow by utilizing the stored PHA;

putting the enriched and domesticated sludge into an anaerobic reactor, and entering a hydrogen-producing and acetic acid-producing stage, wherein hydrogen and acetic acid can be used as substrates for synthesizing PHA; in a sequencing batch reactor, microorganisms firstly generate PHA by taking organic acid as a raw material under anaerobic conditions, and then utilize the generated hydrogen and carbon dioxide generated in a high-level oxidation process as raw materials to generate PHA (hydrogen is used as an energy source, and carbon dioxide is used as a carbon source) under micro-aeration conditions;

PHA accumulated in sludge cells needs to be dissolved by a process to extract PHA in the cells, a Switchable Anionic Surfactant (SAS) is used for leading the surfactant to enter a lipid membrane, and the volume of the cell membrane is increased until the cell membrane is broken; then forming micelles of surfactant and membrane phospholipids and releasing PHA granules; surfactants may also solubilize proteins and other molecules from the non-polymeric cytoplasm (NPCM);

sewage enters an SBR reactor 14 from a water inlet pipe 2, an online COD sensor 11 is arranged in the reactor and is connected with a PCL system, and the PCL system controls an aeration device; when the content of COD in the system is less than 50 mg/L, opening an aeration device, and synthesizing PHA by taking hydrogen and carbon dioxide as raw materials under a micro-aeration state; water is discharged from a water outlet pipe 4; introducing carbon dioxide into the SBR reactor 14 in an aeration stage, wherein the sludge age of the SBR reactor 14 is 5 days, and adding a proper amount of SAS into the residual sludge collector 12 every ten days; after the sludge is subjected to wall breaking, PHA is precipitated to the lower part, supernatant is pumped to a collector 13 with a total phosphorus sensor through a pump 7, the amount of added iron salt can be calculated according to the total phosphorus content, and proper iron salt is added to the collector 13 with the total phosphorus sensor through a PCL system to obtain iron pyrite precipitate; finally, introducing carbon dioxide to ensure that the SAS is insoluble in water, recovering the SAS for recycling, and recovering the PHA precipitate.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.