CN113213715A - Combined treatment method for fermentation antibiotic production wastewater - Google Patents

Abstract

The invention discloses a combined treatment method of fermentation type antibiotic production wastewater, which sequentially performs reinforced hydrolysis treatment on antibiotic production and anaerobic fermentation by using an anaerobic membrane bioreactor (AnMBR). Aiming at the characteristics that high-concentration antibiotics and suspended particulate matters cannot be slowly degraded in anaerobic fermentation inlet water, the method selectively destroys the antibiotics in the wastewater through intensified hydrolysis to remove biological inhibition, and then is coupled with an anaerobic membrane bioreactor to realize efficient removal of COD and suspended matters in the wastewater. According to the invention, antibiotics in the wastewater are destroyed in front of a biochemical system, the antibiotic pressure of anaerobic microorganisms is relieved, and the screening and enrichment of antibiotics on drug-resistant bacteria and drug-resistant genes are blocked, so that the control of the drug-resistant genes in the high-antibiotic wastewater treatment process is realized. The method disclosed by the invention is simple to operate, low in cost, high in removal rate, good in running stability, wide in adaptability and suitable for popularization and application.

Description

Combined treatment method for fermentation antibiotic production wastewater

Technical Field

The invention relates to a high-efficiency and safe treatment method of pharmaceutical wastewater, in particular to a treatment method of fermentation antibiotic pharmaceutical wastewater, belonging to the fields of environmental engineering and high-concentration degradation-resistant wastewater treatment.

Background

China is a main production base of the fermented antibiotics in the world, and the production of the fermented antibiotics plays an important role in the economy of China. The production of the fermentation antibiotics mainly comprises the steps of fermentation, filtration, extraction, refining and the like, the Chemical Oxygen Demand (COD) of the pharmaceutical wastewater is high, the concentration of colloids and suspended matters (SS) is high, the composition is complex, the concentration of the antibiotics is high, and the fermentation antibiotics are typical high-concentration refractory organic wastewater.

Anaerobic biological treatment processes, particularly Upflow Anaerobic Sludge Blanket (UASB) processes, are well suited for the efficient treatment of high concentration wastewater and are widely used in many industrial wastewaters, but antibiotics in pharmaceutical wastewaters can destroy the sludge activity and stability, causing system collapse. In addition, the high-concentration antibiotic pressure can also screen and enrich antibiotic-resistant bacteria and drug-resistant genes, and increase the safety risk of yielding water and excess sludge.

Among a plurality of treatment technologies, the intensified hydrolysis-UASB treatment technology is a common technical means for treating fermentation pharmaceutical wastewater at present, is widely applied in the industry, and has the core technology that: the high-concentration antibiotics in the wastewater are selectively destroyed by enhanced hydrolysis, the antibiotics are thoroughly blocked at the source, and the inhibition of the antibiotics on a biochemical system is removed; the high-efficient of high concentration COD in the waste water is got rid of to the coupling UASB reactor realization again, ensures the steady operation of rear end denitrogenation biochemical system, controls resistant fungus and resistant gene's enrichment and propagation well, and this combined technology has easy operation, handles advantages such as high-efficient, but: the technology has the following technical problems: 1. the combined process can only ensure that the UASB of the engineering has higher COD removal rate (the load is less than 2gCOD/L/d, the removal rate is more than 50 percent) under low load, and acidification and collapse can occur under high load. UASB has the phenomenon of granular sludge loss, and the granular sludge needs to be supplemented every time the UASB is operated for a period of time, thereby increasing the additional cost. Therefore, how to solve the above problem becomes a bottleneck limiting the application of the technology.

In the traditional intensified hydrolysis-UASB process, because fermentation wastewater contains a large amount of protein and microbial metabolites, the protein is easy to deform under heat during intensified hydrolysis treatment, so that suspended matters in the wastewater are increased. The organic particles undergo decomposition and hydrolysis processes which are undoubtedly very slow, in order to be converted into small molecules which can be used by microorganisms.

Decomposition refers to the slow breakdown of complex organic matter into polysaccharides, proteins and lipids, while also producing soluble and insoluble inert substances; the hydrolysis process is to convert polysaccharide, protein and lipid into sugar, amino acid, long chain fatty acid, etc. extracellularly.

According to the first model of anaerobic digestion (ADM1), the process of decomposition and extracellular hydrolysis of organic particulates is the rate limiting step of the anaerobic fermentation process in high SS wastewater treatment. SS in the wastewater wraps the surface of the granular sludge and blocks the pores of the granular sludge, so that the mass transfer efficiency is reduced, and the activity of the granular sludge is inhibited. Research shows that after UASB runs for three months by using high SS fermentation pharmaceutical wastewater as a substrate, the acid production capacity of the UASB is severely inhibited, and the methane production capacity of the UASB is completely lost. Moreover, the SS pressure can cause the loss of the granular sludge, and the protein particles can form foam under the pushing of anaerobic gas production to drive the granular sludge to rise and wash out from the reactor, which is not favorable for the stable operation of UASB.

Therefore, after the intensified hydrolysis, the selection of the reactor which can simultaneously carry out the SS high-efficiency decomposition and the COD high-efficiency removal is the key for improving the treatment efficiency.

Anaerobic membrane bioreactors (AnMBR) are sewage treatment processes that effectively combine anaerobic fermentation with membrane technologies. The process has the traditional advantages of anaerobic biological treatment, remarkably improves the quality of effluent water through the filtering and intercepting action of the membrane, maintains high-concentration microorganisms in the reactor, further improves the decomposition and conversion efficiency of organic matters, and effectively makes up the defects of the traditional anaerobic biological treatment process. The AnMBR can enable dissolved organic matters which are easy to degrade to pass through a filtering membrane along with water, so that organic suspended matters which are difficult to degrade and anaerobic sludge in the reactor are intercepted in the reactor, the separation of Hydraulic Retention Time (HRT) and Solid Retention Time (SRT) is realized, and SS which is slowly decomposed is intercepted in the reactor until the SS is completely decomposed. AnMBR has demonstrated superior performance in the treatment of high SS wastewater such as kitchen waste, coffee grounds, palm oil and oil sludge wastewater.

In the application of AnMBR, the most important indicator is membrane fouling. According to previous researches, the most important factor influencing membrane pollution is sludge concentration, and the higher the sludge concentration is, the more serious the membrane pollution is. This is because the higher the sludge concentration is, the more Soluble Microbial Products (SMP) and Extracellular Polymeric Substance (EPS) secreted by the microorganisms are, and they are mainly some polysaccharides and proteins, and the smaller the particle size, they are liable to cause the clogging of the membrane pores, and reduce the flux of the membrane.

The suspended particles in the fermented pharmaceutical wastewater are mainly proteins (such as proteins in raw materials and proteins secreted by microorganisms) denatured by heat at high temperature. After high-temperature treatment, the protein partially dissolved in the pharmaceutical wastewater is in a colloid or particle state due to the change of a secondary structure, the solubility is reduced, the viscosity is increased, and the hydrophobicity is enhanced. Although they all have the potential for anaerobic degradation, there is a large difference in particle size compared to other organic suspensions. The average particle size of the protein particles is about 0.4 μm, even smaller than that of the anaerobic microorganisms, and the protein particles in the fermentation wastewater may accelerate membrane fouling, so that the stability and high efficiency of the AnMBR reactor cannot be guaranteed.

Moreover, although the fermented pharmaceutical wastewater contains protein particles, the content of the protein particles is only about 1 to 2 per thousand, and the content of suspended matters in the common high-SS wastewater can reach more than 10 percent, so that people rarely pay attention to the removal of the protein particles with the concentration which is not very high. However, long-term experiments by patent authors prove that protein particles in fermentation pharmaceutical wastewater can significantly affect the stability and efficiency of the UASB reactor. Therefore, despite many advantages of AnMBR, there has been less research on AnMBR treatment of fermentation-based pharmaceutical wastewater.

Although membrane fouling limits the application of AnMBR to pharmaceutical wastewater treatment, AnMBR has great potential compared to other treatment modalities. First, protein particles can stay within the AnMBR until completely decomposed, enabling complete removal of contaminants, while transfer of contaminants is achieved by non-physicochemical separation. And secondly, the formation of the sludge filter cake layer and the interception of the membrane further improve the quality of the effluent, and are more beneficial to subsequent high-efficiency treatment. And thirdly, suspended matters and COD are removed synchronously without an additional pretreatment mode, so that the treatment process is simplified, and the treatment space and the cost are saved.

In the conventional AnMBR system, the biomass of the microorganisms is positively correlated with the fouling of the membrane, i.e. the higher the biomass, the faster the membrane fouling, as indicated by the shorter the period of membrane cleaning. The particle size of anaerobic microorganisms is usually in the order of tens to hundreds of microns, and general membrane fouling is also due to the microorganisms and their metabolites clogging the surface and internal pores of the membrane, resulting in a decrease in membrane flux, and thus the membrane needs to be washed to maintain good performance. In order to alleviate the problem, under the condition of not washing the membrane, biogas aeration or membrane shaking is generally selected to reduce the attachment of microorganisms and metabolites thereof on the surface of the membrane. That is, the cleaner the surface of the film, the better the performance of the film.

The biogas aeration is to collect biogas in the anaerobic reactor by an air pump, aerate the surface of the membrane, wash the surface of the membrane by utilizing the longitudinal shearing force formed by bubbles and wash out microorganisms and metabolites thereof attached to the membrane. The membrane shaking means that the membrane shaking is caused by mechanical shaking, jet flow or aeration and the like, and the adhesion of microorganisms and metabolites thereof is avoided or alleviated by means of the vibration of the membrane or the action of external shearing force in the shaking process. Both of these are common ways to slow the rate of membrane fouling.

After the fermentation wastewater is subjected to the intensified hydrolysis treatment, protein dissolved in the wastewater is thermally denatured and precipitated to become protein particles with the particle size of several micrometers to dozens of micrometers, and the particle size of the protein particles is smaller than the diameter of microorganisms, so that membrane pollution is relatively easily caused.

The 'microorganism dynamic composite membrane' formed by the method artificially controls microorganisms to be loaded on the surface of the filter membrane to form a layer of microbial membrane. When the membrane normally runs, the microbial membrane is equivalent to a filter cake layer, and can intercept protein particles which are not decomposed in the wastewater, so that the protein particles are prevented from blocking membrane pores of the filtering membrane; the protein particles trapped on the surface of the microbial membrane can be decomposed into soluble small-molecule organic matters by microbes, and can be further converted into methane. However, since the protein particles are decomposed by surrounding microorganisms to generate pores, newly growing microorganisms can be attached to replace aged microorganisms, which is a dynamic process. The microbial film thus formed is a dynamic microbial film which adheres to the surface of the filter membrane of the AnMBR to form a "microbial dynamic composite membrane". The formed membrane is coupled, and the membrane pollution caused by protein particles is relieved. When the reactor discharges water, the water is firstly filtered by the microbial membrane and then filtered by the filter membrane. The formed microbial membrane is equivalent to the fact that a filter cake layer is added on the surface of a filter membrane, although the pore diameter is different, fine protein particles can be effectively intercepted due to certain thickness, and the protein particles are prevented from directly contacting the filter membrane to block the pore of the filter membrane; secondly, the microbial film is formed by anaerobic microorganisms, has the capacity of degrading organic matters, can decompose and degrade protein particles, and can be better removed; thirdly, even if the protein particles are mixed in the dynamic membrane of the microorganism, because the protein particles can be degraded and new microorganisms can be regenerated or attached, the dynamic membrane of the microorganism is not fixed but can be continuously regenerated and updated, thereby being more beneficial to maintaining the activity of the microorganism. The filter membrane mainly has two functions: firstly, the carrier is used as a dynamic membrane of the microorganism; secondly, filtering the filtrate obtained after the filtration of the microorganism dynamic membrane for the second time to ensure the quality of the effluent.

At present, the research of realizing the synergistic removal of COD and drug resistance genes in the fermentation pharmaceutical wastewater by comprehensively applying the technologies of reinforced hydrolysis and anaerobic membrane bioreactor is not available. Based on the mechanism, the intensified hydrolysis-AnMBR technology is provided, the antibiotic titer in the wastewater is selectively destroyed through intensified hydrolysis, the biological inhibition of the wastewater is relieved, and the AnMBR is coupled, so that the high load and high efficiency removal of SS and COD in the wastewater are realized, and the water quality and the safety of the effluent are improved.

The invention has the innovation point that the UASB in the prior art of 'reinforced hydrolysis-UASB process' is replaced by a more stable and efficient 'anaerobic membrane bioreactor' process.

The invention content is as follows:

the invention aims to provide a combined treatment method of fermentation type antibiotic pharmaceutical wastewater, aiming at the technical problems that the subsequent anaerobic sludge biological treatment capacity is obviously reduced due to the increase of suspended matters (especially protein particles) in the prior process of treating antibiotic wastewater by adopting reinforced hydrolysis, so that the anaerobic biological treatment cannot stably run and even loses the treatment capacity, the method comprises the steps of firstly selectively destroying antibiotics in the wastewater by reinforced hydrolysis, and then efficiently and synchronously removing COD (chemical oxygen demand) and suspended matters in the wastewater by combining an anaerobic membrane bioreactor; the antibiotic in the wastewater system treated by the method is thoroughly removed, and the system has no antibiotic pressure, so that the generation and the propagation of antibiotic-resistant bacteria and drug-resistant genes can be thoroughly controlled; the suspension is retained in the reactor until it is completely decomposed and converted to methane.

In order to achieve the purpose of the invention, the invention provides a combined treatment method of fermented antibiotic pharmaceutical wastewater, which comprises the steps of sequentially carrying out intensified hydrolysis treatment on the fermented antibiotic pharmaceutical wastewater and carrying out anaerobic biological treatment by using an anaerobic membrane bioreactor.

Wherein, the reinforced hydrolysis treatment is to carry out hydrolysis treatment on the fermentation antibiotic pharmaceutical wastewater under the heating condition to destroy the pharmacodynamical functional groups of the antibiotic, so that the antibiotic completely loses antibacterial activity and the biodegradability of the wastewater is improved.

The main components of the fermented antibiotic pharmaceutical wastewater are fermentation raw materials (sugars and proteins), microbial metabolites (mainly proteins), and microbial fermentation products (antibiotics). Of the three main classes of substances, antibiotics inhibit biological treatment in anaerobic membrane bioreactors, and antibiotics are not biodegradable, and the other two classes (sugars, proteins) are easier to remove by anaerobic biodegradation.

The components of the fermented antibiotic pharmaceutical wastewater are complex, and although other processes such as oxidation and the like destroy antibiotics, other organic matters (such as starch, protein and the like) in the wastewater are oxidized in a large quantity due to the fact that oxidation reaction has no selectivity, so that the oxidation efficiency of the antibiotics is reduced; in addition, since starch, protein and the like are major contributors of COD, and from the viewpoint of economy and the like, it is desirable that most of COD is not removed by oxidation and the like, but is degraded by microorganisms, because the cost of microbial degradation is low compared to oxidation, and products of anaerobic fermentation are carbon dioxide and methane, which can be burned as energy, power generation and the like, corresponding to energy recovery.

Antibiotics (such as oxytetracycline, erythromycin and the like) have an inactivation effect on most bacteria, if the wastewater contains the antibiotics with higher concentration, the anaerobic biological treatment system is easy to collapse, the biodegradation treatment cannot be carried out, and the effect of wastewater treatment cannot be achieved, so that the antibiotics in the pharmaceutical wastewater need to be destroyed. The method of the invention adopts a high-temperature pyrohydrolysis method to selectively destroy antibiotics, and retains the main contributors (starch and protein) of COD, which are used for subsequent anaerobic biological treatment and are utilized by anaerobic microorganisms. Because antibiotics are structurally unstable and easily hydrolyzed in aqueous solution. Applying high temperature to the antibiotics to accelerate hydrolysis; and other substances in the wastewater have high solubility, are relatively stable in aqueous solution and are not easy to hydrolyze, so that the aim of selectively destroying antibiotics is fulfilled.

Particularly, the temperature of the intensified hydrolysis is controlled to be 85-160 ℃, preferably 100-160 ℃, and further preferably 110 ℃; the hydrolysis treatment time is 0.5-6 h, preferably 1-2 h.

In particular, high-pressure hot steam is adopted to heat the antibiotic wastewater in the process of the intensified hydrolysis treatment until the temperature is raised to 85-160 ℃, preferably 100-160 ℃, and further preferably 110 ℃.

Particularly, the method further comprises the step of adjusting the pH value of the wastewater to 5-7 and then carrying out the reinforced hydrolysis treatment.

Particularly, the pH value of the antibiotic pharmaceutical wastewater is adjusted to 5-7 by using concentrated hydrochloric acid or concentrated sodium hydroxide.

Although the structure (pharmacodynamic functional group) of the antibiotic is selectively destroyed by the intensified hydrolysis, so that the antibiotic loses bacteriostatic activity, the original dissolved protein in the wastewater is denatured and separated out by the high-temperature treatment, and the separated protein particles are not beneficial to the stable and efficient operation of a conventional anaerobic reactor such as UASB, which is shown in the phenomena of low COD removal rate, low methane yield, serious particle sludge loss and the like. Therefore, an anaerobic membrane bioreactor (AnMBR) more suitable for treating wastewater containing particulate matter is selected as the anaerobic treatment unit to ensure the stability of the anaerobic system.

The wastewater after the enhanced hydrolysis treatment enters an anaerobic membrane bioreactor, and soluble organic matters and protein particles are decomposed by anaerobic sludge in the reactor to achieve the effect of degrading COD (chemical oxygen demand) and suspended matters. Suspended matter in the wastewater is retained due to the filtration action of the membrane until it is degraded by microorganisms. In addition, the filtering action of the membrane can also intercept macromolecular organic matters in anaerobic sludge and water so as to improve the quality of effluent water.

Wherein, an anaerobic membrane bioreactor is adopted for the anaerobic biological treatment.

Anaerobic biological treatment, also known as anaerobic fermentation, is divided into two processes, an acid forming phase and a methane forming phase. The acid generation phase is that organic matters are decomposed, hydrolyzed and subjected to acid generation under the action of acid-producing bacteria to become volatile organic acids (fatty acids containing 2-6 carbon atoms). The methanogenic phase means that volatile fatty acids are further decomposed to produce acetic acid and hydrogen (acetic acid production), which are then utilized as a raw material by methanogens to produce methane (methanogenesis).

The invention utilizes the anaerobic membrane bioreactor to carry out anaerobic biological treatment, namely the wastewater after the reinforced hydrolysis treatment is finally converted into methane through the processes of decomposition, hydrolysis, acid generation, acetic acid generation, methane generation and the like, and can be recycled.

Particularly, the anaerobic biological treatment temperature is 30-60 ℃, preferably 35-55 ℃, and more preferably 35 ℃ medium temperature AnMBR or 55 ℃ high temperature AnMBR.

In particular, medium temperature (35 ℃) or high temperature (55 ℃) AnMBR is used for anaerobic biological treatment.

Particularly, the sludge concentration in the AnMBR is controlled to be 10-25 g/L, and preferably 15-20 g/L.

In particular, the AnMBR may be of the membrane internal and external type, preferably of the membrane internal type.

The membrane built-in means that the filtering membrane is immersed in the reactor or immersed in a membrane pool communicated with the reactor; by external to the membrane is meant that the membrane is placed outside the reactor. A continuous stirring complete mixing type reactor is selected as a reactor type for anaerobic treatment so as to realize the full decomposition and hydrolysis of suspended substances in the wastewater.

In particular, the anaerobic reactor and membrane in anmbrs are typically in a unitary and split positional relationship, preferably split.

In particular, the types of membranes are classified into flat sheet membranes, hollow fiber membranes and tubular membranes, and preferably hollow fiber membranes.

In particular, the material of the membrane may be classified into an organic polymer membrane, a metal membrane and a ceramic membrane, and is preferably an organic polymer membrane, and more preferably a polytetrafluoroethylene membrane.

In particular, the pore diameter of the membrane is usually 0.1 to 0.4. mu.m, preferably 0.1. mu.m.

In particular, the water feeding method is continuous water feeding and intermittent water feeding, and is preferably continuous water feeding.

Particularly, in the anaerobic biological treatment process, the alkalinity of the wastewater entering the anaerobic biological reactor is controlled to be less than or equal to 3500mg/L, preferably 1000-3000 mg/L, and more preferably 2000-3000 mg/L.

In particular, the flux of the membrane is usually 6 to 15LMH, preferably 10 to 12 LMH.

Particularly, the starting stage of the membrane is to make microorganisms adhere to the surface of the membrane, and the thickness of the membrane is 1-2mm, and preferably 1.5 mm. The attached microbial membrane retains smaller protein particles in the wastewater (including protein particles originally contained in the wastewater and produced by heat denaturation and decomposition by the enhanced hydrolysis treatment).

Particularly, in the anaerobic biological treatment process, the flow rate of biogas entering the anaerobic biological reactor is controlled to be 0.5-3L/min, and preferably 1L/min.

In particular, the water discharge mode of the membrane is usually continuous water discharge and intermittent water discharge, and is preferably intermittent water discharge.

Particularly, when AnMBR is intermittent effluent, the operation time of the filtering membrane, namely the working time, is 2-4 min, and preferably 3 min; the stop operation time of the filtering membrane, namely the rest time of the membrane is 5-100 min.

Particularly, the pH of the influent water of the anaerobic organisms is 6-8, preferably 6.5-7, and further preferably 7; the pH of the effluent after the anaerobic biological treatment is 6.8-8.5, preferably 7.2-8.0, and further preferably 7.5-7.95.

In particular, the concentration of volatile fatty acids in the effluent after anaerobic biological treatment is less than 500mg/L, preferably less than 400 mg/L.

In particular, the pressure difference across the membrane during the anaerobic biological treatment should be greater than-40 kPa, preferably greater than-30 kPa. It is noteworthy that the transmembrane pressure difference itself should be negative.

Wherein the treatment load in the anaerobic biological treatment process is more than 4gCOD/L/d, preferably 5-10 gCOD/L/d, and further preferably 5-6 gCOD/L/d.

In particular, the fermentation antibiotics are a large group of antibiotics such as tetracyclines, macrolides, beta-lactams, amidoalcohols, aminoglycosides, polypeptides, lincosamides and the like.

Wherein, because the particle size of the protein particles in the wastewater is small and the degradation is slow, the pollution of the membrane can be caused, thereby increasing the frequency of membrane washing. Therefore, on the basis of the original AnMBR, a technical mode of 'microorganism dynamic composite membrane' is provided to slow down the pollution of the membrane and reduce the membrane washing frequency.

Particularly, before the anaerobic biological treatment, the method also comprises the step of pretreating the anaerobic membrane bioreactor, so that a dynamic microorganism layer is loaded on the surface of a filter membrane of the anaerobic membrane bioreactor, and the loaded dynamic microorganism membrane and the filter membrane form a dynamic microorganism composite membrane.

Wherein the pretreatment comprises the following steps:

A) preparing a pre-treatment nutrient solution

Adding glucose and soybean peptone serving as substrates into sterile water to prepare a nutrient solution, adding a phosphate buffer solution, and adjusting the pH value of the nutrient solution to 6.5-7.5;

B) closing a biogas aeration pump of the AnMBR, injecting anaerobic sludge into the AnMBR, and introducing nitrogen at the same time until the oxygen in the reactor is emptied;

C) starting a water outlet pump of the AnMBR, pumping water outwards, monitoring transmembrane pressure difference of a filter membrane of the AnMBR, starting a biogas aeration pump of the AnMBR until the transmembrane pressure difference of the filter membrane reaches below-10 kPa, stopping pumping water until the transmembrane pressure difference is constant to be-3 to-9 kPa, and uniformly loading a microbial layer on the surface of the filter membrane of the AnMBR.

Particularly, the COD value of the nutrient solution prepared in the step A) is 4500-5500 mg/L; the mass ratio of the glucose to the soybean peptone is 1: (1-2); the pH value of the nutrient solution is preferably 6.8-7.2.

In particular, the phosphate buffer is a mixed system of pH 7 prepared from disodium hydrogen phosphate and sodium dihydrogen phosphate. Action of phosphate buffer: providing a certain phosphorus element as an element required by the growth of microorganisms; plays a role in buffering pH and preventing rapid acidification.

Wherein, the anaerobic sludge in the step B) is anaerobic flocculent sludge.

In particular, the nitrogen gas has a purity of 99.99%.

Wherein, in the step C), when the transmembrane pressure difference reaches-10 to-12 kPa, a biogas aeration pump of the AnMBR is started. Particularly, the flow rate of a biogas aeration pump of the AnMBR is controlled to be 0.5-3L/min, and preferably 0.5-2L/min. The thickness of the microorganism layer loaded on the surface of the filtering membrane is adjusted by adjusting the flow of biogas aeration.

In particular, when the transmembrane pressure difference is constantly-5 to-9 kPa, more preferably-5 to-7 kPa), the water pumping is stopped.

Particularly, the thickness of the formed surface microorganism layer uniformly supported on the AnMBR is 1-2mm, and preferably 1.5 mm.

Compared with the prior art, the invention has the following advantages and benefits:

aiming at the requirement that high-concentration antibiotics and suspended particles cannot exist in inlet water in the traditional UASB treatment process, the method selectively destroys the antibiotics in the wastewater through intensified hydrolysis, removes the biological inhibition of the antibiotics, then realizes the high-efficiency removal of suspended matters and high-concentration COD in the wastewater through the anaerobic membrane bioreactor, and the intensified hydrolysis and the anaerobic membrane bioreactor have synergistic effect to efficiently remove the COD in the wastewater, and synergistically inhibit the generation of drug-resistant bacteria and drug-resistant genes in the wastewater, thereby reducing the safety risk of outlet water and residual sludge.

1. According to the method, the antibiotics in the fermentation antibiotic wastewater are inactivated before the biological treatment of the fermentation antibiotic wastewater, so that the source blockage of the antibiotics is realized, and the generation of resistance genes in the microbial treatment process is avoided.

The method of the invention carries out the reinforced hydrolysis treatment on the antibiotic wastewater, obviously reduces the antibiotic concentration in the wastewater, and thoroughly destroys the antibiotic selectivity, wherein the antibiotic concentration of the antibiotic wastewater after the reinforced hydrolysis treatment is less than 5mg/L, even less than 1 mg/L.

2. Although the antibiotic concentration of the fermentation pharmaceutical wastewater is high, many common pretreatment modes are not suitable for the actual wastewater treatment due to the complex water quality and much interference, but the antibiotic reinforced hydrolysis in the method is less interfered by a matrix, and the effect is good in the actual water treatment.

3. The concentration of suspended matters in the fermentation type antibiotic wastewater is high, the fermentation type antibiotic wastewater is not suitable for the treatment of the conventional UASB, and when the reinforced hydrolysis treatment is adopted, the protein in the wastewater is subjected to thermal denaturation, so that the amount of the suspended matters (SS) in the wastewater is increased, and suspended matter particles can be converted into small molecules which can be utilized by microorganisms only through slow decomposition and hydrolysis processes.

4. In the method, the AnMBR processing load is high, and the organic processing load reaches 6-8 gCOD/L/d; the sludge yield is low, methane is generated, and the recovery of energy is realized. The method adopts the anaerobic membrane bioreactor to carry out anaerobic biological treatment on the wastewater after the reinforced hydrolysis treatment, has high COD removal rate, and realizes the high-efficiency treatment of the fermented pharmaceutical wastewater.

5. According to the method, a microbial membrane with the thickness of 1-2mm is uniformly loaded on the surface of the filtering membrane of the reactor in the early stage of AnMBR treatment, and the loaded microbial membrane and the AnMBR formed by the filtering membrane are used for carrying out biological dynamic composite membrane for anaerobic biological treatment, so that membrane pollution is reduced, and the membrane washing period is prolonged.

6. The method has the advantages of simple operation, simple process flow, easy control of operation conditions, stable treatment effect, low operation and maintenance cost and large-scale popularization and application.

In the method, suspended matters in the fermentation antibiotic pharmaceutical wastewater after the intensified hydrolysis are mainly protein particles, and the protein particles have stronger hydrophobicity due to the exposure of internal hydrophobic groups in the heat treatment process, so that the protein particles are separated out to be colloid or granular. Therefore, by utilizing the characteristics of the membrane interception and the degradation of organic suspended matters by anaerobic organisms, protein particles can be kept in the reactor for a long time until being decomposed, and anaerobic sludge cannot be lost due to the interception of the membrane. And the sludge in the AnMBR is flocculent sludge, so that the activity cannot be lost due to the coating of protein particles. The biological dynamic composite membrane is used as a treatment mode before water outlet, and the reduction of membrane flux caused by the increase of transmembrane pressure difference of the filter membrane along with the increase of running time is delayed, so that the membrane pollution is slowed down, the membrane washing period is prolonged, and the full degradation of protein particles in the wastewater is promoted.

Description of the drawings:

FIG. 1 is a schematic diagram of a split type anaerobic membrane bioreactor.

The specific implementation mode is as follows:

the invention will be further described with reference to specific embodiments, and the advantages and features of the invention will become apparent as the description proceeds. These examples are illustrative only and do not limit the scope of the present invention in any way. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention, and that such changes and modifications may be made without departing from the spirit and scope of the invention.

The present invention will be described in further detail with reference to examples, but the present invention is not limited to these examples.

Examples 1, 1A, 1B; comparative examples 1 to 1C will be described with reference to examples of treating oxytetracycline-derived wastewater. The production of terramycin comprises the processes of fermentation and extraction, the residual bacteria liquid is filtered by a plate frame to obtain waste mother liquid for terramycin production, the mother liquid has very high bacteriostatic ability and can not be directly biologically treated, and the water quality of the waste mother liquid is as follows:

COD: 12000-14000 mg/L; a pH of about 4.8; the concentration of oxytetracycline is: 700-900 mg/L; the concentration of suspended matters is 200-300 mg/L.

To achieve efficient, low-cost biological treatment of the wastewater, the residual oxytetracycline should be destroyed first to remove the biological inhibition.

In the examples, the waste mother liquor COD of oxytetracycline production is 12000mg/L, pH is 4.8, oxytetracycline concentration is 900mg/L, and suspended matter concentration is 200 mg/L. It should be noted that the data of the wastewater treatment process, particularly anaerobic treatment, are shown by calculating the average value since a large number of data are accumulated by reflecting the effect of long-term stable operation.

In the examples, an anaerobic membrane bioreactor (AnMBR) is described by taking a split-type membrane-embedded reactor as an example, wherein a hollow fiber membrane is taken as an example for a filtration membrane. The filtering membrane can also be a flat membrane, and the AnMBR can also be an integral type.

In the embodiment of the present invention, parameters of the hollow fiber membrane used in the AnMBR in the comparative example are as follows: the pore diameter of the membrane is 0.1 μm (usually 0.1-0.4 μm); the membrane area was 0.1m²。

Example 1: method for treating waste mother liquor in terramycin production by using intensified hydrolysis-AnMBR technology

1. Enhanced hydrolysis

1-1, adding a concentrated sodium hydroxide solution into the oxytetracycline production waste mother liquor under a stirring state, and adjusting the pH of the waste mother liquor to 7 (usually, the pH is 5-7, preferably 7);

1-2, introducing the waste mother liquor with the pH adjusted into a heat exchanger, and preheating the waste mother liquor to enable the temperature of the waste mother liquor to rise to 60 ℃ (usually 40-60 ℃); then heating the waste mother liquor until the temperature of the waste mother liquor rises and is kept at 110 ℃ (usually 85-160 ℃), and carrying out intensified hydrolysis treatment on the waste mother liquor under the condition that the temperature is 110 ℃ (usually 85-160 ℃), wherein the intensified hydrolysis treatment time is 1h (usually 0.5-6 h);

the method of the invention heats the antibiotic pharmaceutical wastewater gradually by heat exchange, and heats the inlet water by using the residual temperature of the outlet water of the heat exchanger, thereby saving the cost and ensuring the safety.

In examples 1-1B and comparative examples 1-1B, the temperature is 110 ℃ and the time is 1 hour for the intensive hydrolysis treatment of the waste mother liquor from oxytetracycline production, and other intensive hydrolysis temperatures such as 85-160 ℃ and the hydrolysis time is 0.5-6 hours are all suitable for the present invention.

1-3, after the enhanced hydrolysis is carried out for 1h, the wastewater is subjected to gradual heat exchange and is cooled to 35 ℃ (usually 30-40 ℃) so as to meet the requirement of medium-temperature anaerobic treatment, and the enhanced hydrolysis wastewater is obtained.

Determining the concentration of antibiotics in the reinforced hydrolysis wastewater by adopting a liquid chromatography-tandem mass spectrometry method; the content of suspended matters is measured by a gravimetric method (the national standard GB11901-89 weight method for measuring suspended matters in water); the alkalinity is measured by GB/T15451-2006 "determination of total alkali and phenolphthalein alkalinity"; measuring the pH value by using a pH meter; the COD value of the effluent after the intensified hydrolysis is determined by adopting a dichromate method (national standard HJ 828-:

the residual concentration of the oxytetracycline in the reinforced hydrolysis wastewater is 0.8mg/L and less than 1 mg/L; the concentration of suspended matters is 1800 mg/L; the pH value of the intensified hydrolyzed wastewater is 6 (usually 5-7); the alkalinity is 2500 mg/L; the COD was 12000 mg/L.

2. Pretreatment of AnMBR

2-1, adding glucose and soybean peptone as substrates into sterile water to prepare a nutrient solution with COD of 5000mg/L (wherein the mass ratio of the glucose to the soybean peptone is 1:1), adding a phosphate buffer solution (namely a buffer system with pH of 7 prepared from sodium dihydrogen phosphate and disodium hydrogen phosphate, and the concentration of the buffer system is 0.1mol/L) as the inlet water of the start-up stage, and the pH of the inlet water of the start-up stage is 7. At this point, there is no suspended matter in the feed water.

COD of the nutrient solution prepared in the starting process of the AnMBR is usually 4500-5500 mg/L, and the mass ratio of glucose to soybean peptone is usually 1: (1-2); the pH of the feed water is usually 6.8 to 7.2.

2-2, closing a biogas aeration pump of the AnMBR, injecting anaerobic flocculent sludge into an anaerobic membrane bioreactor (AnMBR), stirring, and simultaneously introducing high-purity nitrogen (99.99%) until the oxygen in the reactor is emptied;

and 2-3, starting a water outlet pump of the AnMBR, pumping water from the end of a membrane tank of the AnMBR outwards, monitoring the transmembrane pressure difference of a hollow fiber membrane of the membrane tank, starting a biogas aeration pump of the AnMBR when the transmembrane pressure difference of the filter membrane reaches below-10 kPa (usually-10 to-12 kPa), controlling the flow rate of aeration to be 1L/min (usually 0.5 to 3L/min), adjusting a microbial layer by adjusting the flow rate of biogas aeration, monitoring the transmembrane pressure difference of the filter membrane at the same time, and stopping pumping water until the transmembrane pressure difference is constant to be-5.05 kPa (usually-3 to-9 kPa, preferably-5 to-9 kPa, and further preferably-5 to-7 kPa). At the initial stage of starting, because the oxygen is exhausted by the high-purity nitrogen, the nitrogen in the reactor is totally nitrogen at the moment, the nitrogen in the reactor can be directly extracted for aeration, and the produced biogas replaces the nitrogen gradually for aeration along with the reaction.

The surface of the hollow fiber membrane of the membrane pool of the AnMBR is uniformly loaded with a microorganism layer, and the initial thickness of the formed microorganism dynamic membrane is 1.5mm (usually 1-2 mm).

3. AnMBR treatment

The reinforced treatment wastewater (namely the reinforced treatment oxytetracycline production waste mother liquor) after the reinforced hydrolysis treatment has removed the inhibition of antibiotics, and better treatment efficiency and operation load can be realized through the high-efficiency AnMBR reactor.

Continuously injecting water into an anaerobic membrane bioreactor (AnMBR) with an effective volume of 8L by using a peristaltic pump, wherein the water is intermittently discharged, and carrying out anaerobic biological treatment on the reinforced hydrolysis wastewater; wherein:

adjusting the organic load and the protein particle load entering the AnMBR by adjusting the water inlet flow, wherein the water inlet flow is 1.3L/d, 2.7L/d, 4L/d and 5.3L/d respectively; the anaerobic biological treatment temperature is 35 ℃ (usually 30-40 ℃); the aeration flow rate of the biogas is kept at 1L/min (usually 0.5-3L/min); the flux of the membrane is controlled to be 12LMH (usually 4-20 LMH); AnMBR intermittently discharges water, namely the operation mode of the membrane is selected to be intermittent operation, the operation is carried out for 3 minutes, the rest time (the rest time is the time interval between two adjacent membrane operations) is changed along with the change of the inflow water flow, and the working time (membrane filtration) and the rest (filtration stopping) time of the membrane are shown in a table 2.

Determining the organic load of anaerobic biological treatment of the AnMBR to be 2, 4, 6 and 8gCOD/L/d respectively according to the inflow, wherein the organic load is calculated according to the formula (1):

organic load ═ C Q/V (1)

Wherein: in equation (1): c: COD concentration (g/L) of inlet water; q: flow rate (L/d); v: AnMBR reactor effective volume (L). The unit is gCOD/L/d.

The feed water should have a pH of 7 (typically 6-8, preferably 6.5-7); the alkalinity of the inlet water is 2500mg/L (generally less than or equal to 3500mg/L, preferably 1000-3000 mg/L, and more preferably 2000-3000 mg/L); the concentration of the sludge in the reactor is 20g/L (usually 10-25 g/L, preferably 15-20 g/L).

The invention is illustrated by continuous water injection into the AnMBR, but intermittent water injection is also applicable to the invention.

Monitoring transmembrane pressure difference (TMP) of the filter membrane in real time during the anaerobic biological treatment, wherein the initial transmembrane pressure difference is-5.05 kPa; monitoring the COD, pH and concentration of volatile fatty acids of the AnMBR effluent; measuring the methane yield in the anaerobic biological treatment process; calculating the COD removal rate of the wastewater treated by the AnMBR; wherein, a pressure sensor is adopted to measure transmembrane pressure difference; the concentration of the volatile fatty acid is determined by a titration method (Q/YZJ10-03-02-2000 determination of the volatile fatty acid); determining the amount of methane generated in the wastewater treatment process by adopting a gas chromatography; the COD removal rate is calculated according to the formula (2); the measurement results are shown in Table 1, in which formula (2) is as follows:

COD removal Rate (C)_in-C_eff)/C_in*100％

In equation (2): c_in、C_effThe COD (mg/L) of the inlet water and the outlet water of the AnMBR anaerobic membrane bioreactor are respectively.

In the invention, the pH value of AnMBR effluent is 6.8-8.5 (preferably 7.2-7.8); the concentration of volatile fatty acids should be less than 500mg/L (preferably less than 400 mg/L).

When the transmembrane pressure difference is lower than-40 kPa, the filtering membrane is considered to be seriously polluted and must be cleaned; when the transmembrane pressure difference is less than-40 kPa, membrane cleaning can be carried out at proper time according to the operation condition. The washing of the filtration membrane is generally carried out at a pressure difference across the membrane of approximately-30 kPa (preferably-30. + -. 1 kPa).

The transmembrane pressure difference is essentially the pressure difference between the inside and the outside of the membrane expressed in kPa, and is negative because of the negative pressure outside the membrane when the reactor is operated. TMP reflects the degree of membrane fouling, with a greater absolute value of TMP indicating an increase in pressure required to pump the water, and a more severe membrane fouling, typically below-40 kPa, indicating that the membrane has been heavily fouled.

In the embodiment of the invention, when the transmembrane pressure difference is-30 kPa, AnMBR treatment is stopped, the membrane is cleaned until the transmembrane pressure difference is larger than-5.5 kPa, then the reinforced hydrolysis wastewater is injected, the anaerobic biological treatment of the wastewater is continued, the transmembrane pressure difference of the filtering membrane is monitored, when the transmembrane pressure difference of the filtering membrane is reduced to about-30 kPa again, the membrane is cleaned, and water injection, biological treatment stopping and membrane cleaning are circularly and repeatedly carried out.

The transmembrane pressure difference (TMP) at each stage was measured with the membrane at rest and the maximum at rest was recorded.

In the embodiment, the time from the start of injecting the hydrolysis-enhanced oxytetracycline wastewater to the first cleaning of the AnMBR membrane is 66 days (namely, the time from the start of injecting the hydrolysis-enhanced wastewater to the time when the transmembrane pressure difference of the filtering membrane reaches-30 kPa). During membrane operation, there is a fraction of unrecoverable contamination that cannot be eliminated with membrane washing. Therefore, during the operation of the membrane, the membrane washing frequency can slowly increase along with the increase of the time, so that the time of the first membrane washing is selected as a reference of the membrane washing frequency (namely, the time interval or the membrane washing period of two adjacent membrane washing).

The parameters of the membrane were as follows: the configuration of AnMBR is a split, membrane-internal reactor, as shown in figure 1.

TABLE 1 AnMBR effluent quality measurement results in examples 1-1B and comparative examples 1 and 1A

TABLE 2 results of the operation of the AnMBR membrane modules in examples 1-1B and comparative example 1

The methane yield in the wastewater treatment process of the method accords with the yield calculated by theory, which shows that the method can keep the stable operation of an anaerobic biological treatment system; and the COD removal efficiency of the wastewater is high, the wastewater treatment load is high, the treatment efficiency is far higher than that of the existing engineering system and the pilot plant test at present, the wastewater treatment capacity is high, the production process is allowed to increase the yield, and the wastewater treatment cost is reduced.

Adjusting the organic load and the protein particle load of the reactor by adjusting the water inlet volume, recording COD of inlet water and outlet water during operation, calculating the removal rate, and detecting the pH value of the outlet water and the result of volatile fatty acid to evaluate the stability of the system.

Under different wastewater treatment loads, measuring COD of inlet water and outlet water, calculating the removal rate of the COD, detecting the pH value of the outlet water, the content of volatile fatty acid and the yield of methane, and measuring results show that: according to the invention, the AnMBR can stably operate, the treatment load can stably operate when the treatment load is 2-8 gCOD/L/d, the COD removal rate is high, wherein when the highest treatment load is 8gCOD/L/d, the COD removal rate reaches 50%, and the daily COD removal rate does not fluctuate greatly; the pH value of effluent is more than 7; the methane yield conforms to the yield calculated theoretically; but the content of the effluent volatile fatty acid is higher than 500mg/L, and the effluent volatile fatty acid is slightly higher. And when the load is 6gCOD/L/d, each index is in a reasonable range and far exceeds the efficiency of the existing engineering system and the pilot test at present.

It is worth noting that in the application of AnMBR, two key factors need to be considered, one is the efficiency of anaerobic biological treatment, which is reflected in indexes such as organic load and COD removal rate; another is membrane sustainability, which is manifested by a pressure difference across the membrane, with a greater absolute value of the pressure difference across the membrane indicating greater membrane fouling. The pressure difference across the membrane should generally be greater than-40 kPa, preferably greater than-30 kPa. The transmembrane pressure difference reflects the pressure required for maintaining the membrane to discharge water, and directly influences the membrane washing frequency. When the load is 6gCOD/L/d, the membrane washing frequency is 48 days/time. When the load is further increased to 8gCOD/L/d, the membrane washing frequency is rapidly increased to 30 days/time.

According to the results of tables 1 and 2, at an organic load of 8gCOD/L/d, although the COD removal rate exceeds 50%, the membrane washing frequency is rapidly increased by 30 days/time from 48 days/time of the organic load of 6gCOD/L/d, which indicates that the membrane pollution speed is increased, so that the filtering membrane is at a serious pollution level. When the organic load is 6gCOD/L/d, the membrane washing period is reduced compared with the previous stage, but the membrane washing period is still at a stable level. This indicates that while the AnMBR can achieve a good removal at an organic loading of 8gCOD/L/d, the organic loading should be controlled to 6gCOD/L/d in view of loading and membrane fouling control.

Example 1A: method for treating waste mother liquor in production of fermentation type oxytetracycline by using intensified hydrolysis-AnMBR technology

1. Enhanced hydrolysis

Same as in step 1 of example 1.

2. Pretreatment of AnMBR

The procedure was carried out in the same manner as in step 2 of example 1 except that the flow rate of aeration of biogas was 2L/min and the thickness of the microbial film uniformly supported on the surface of the filtration membrane was 1.0 mm.

3. AnMBR treatment

Same as in step 3 of example 1.

The initial transmembrane pressure difference was-3.42 kPa. Measuring COD of inlet water and outlet water of the AnMBR; measuring pH of effluent, content of volatile fatty acid, and methane yield, recording working/rest time of membrane, measuring transmembrane pressure difference and first membrane washing period, and determining results shown in tables 1 and 2.

Example 1B: method for treating waste mother liquor in production of fermentation type oxytetracycline by using intensified hydrolysis-AnMBR technology

1. Enhanced hydrolysis

Same as in step 1 of example 1.

2. Pretreatment of AnMBR

The procedure was carried out in the same manner as in step 2 of example 1 except that the flow rate of aeration of biogas was 0.5L/min and the thickness of the microbial membrane uniformly supported on the surface of the filtration membrane was 2.0 mm.

3. AnMBR treatment

Same as in step 3 of example 1.

The initial transmembrane pressure difference was-8.68 kPa. Measuring COD of inlet water and outlet water of the AnMBR; measuring pH of effluent, content of volatile fatty acid, and methane yield, recording working/rest time of membrane, measuring transmembrane pressure difference and first membrane washing period, and determining results shown in tables 1 and 2.

Combining the results of examples 1-1B, the anaerobic treatment effect of each example was similar for the AnMBR treatment effect, i.e., from the standpoint of organic loading and COD removal rate. From the aspect of membrane pollution control, the three embodiments can keep a longer membrane washing period under higher organic load, which shows that the microorganism membrane loaded on the surface of the filter membrane in the step 2) of the method and the microorganism dynamic composite membrane process formed by the filter membrane are applicable to a system for treating fermentation pharmaceutical wastewater by AnMBR and the treatment effect is obvious. As can be seen from comparative examples 1 to 1B, the effect is best when the thickness of the dynamic membrane of microorganisms is controlled to 1.5 mm. This is because the dynamic membrane of the microorganism cannot function to retain protein particles at a low thickness. When the thickness is too high, the microorganisms themselves become a limiting parameter for the operation of the membrane.

Comparative example 1: method for treating waste mother liquor in terramycin production by using intensified hydrolysis-AnMBR technology (without using dynamic composite membrane)

1. Enhanced hydrolysis

Same as in step 1 of example 1.

2. AnMBR treatment

The procedure was followed in step 3 of example 1 except that the hydrolysis-enhanced wastewater was continuously injected directly into the AnMBR, the aeration rate of the biogas was maintained at 4L/min, and the initial transmembrane pressure difference (maximum value at rest) of the filtration membrane was measured while the membrane was at rest and was-1.14 kPa. In the existing AnMBR treatment process, the normal aeration rate is above 4L/min, and the aeration rate is lower than 4L/min, which is more likely to cause membrane pollution.

The difference from the example 1 is that the AnMBR directly treats the waste mother liquor after the intensified hydrolysis of the oxytetracycline production, and a dynamic composite membrane is not cultured, namely a microorganism layer is not loaded on the surface of a filter membrane.

Measuring COD of inlet water and outlet water of the AnMBR; the pH of the effluent, the volatile fatty acid content, the methane production, the membrane working/rest time, the transmembrane pressure difference and the first membrane wash cycle were determined and the results are shown in tables 1 and 2.

Comparing the results of comparative example 1 with examples 1-1B, although comparative example 1 was not significantly different from examples 1-1B in the load and removal rate of AnMBR, there was a large difference in the membrane washing frequency. The membrane washing frequency of comparative example 1 was much higher than that of example 1-1B, mainly because the protein particles blocked the membrane pores and became the main contributor to membrane fouling. Meanwhile, the application of the dynamic composite membrane in the method of the invention can greatly improve the operation effect of the membrane, reduce the membrane washing frequency and prolong the membrane washing period.

When the oxytetracycline production wastewater is treated, compared with the 'enhanced hydrolysis-AnMBR' adopting a microorganism dynamic composite membrane in the method, the effluent quality of the conventional 'enhanced hydrolysis-AnMBR' is similar, but the membrane pollution is serious, and the membrane washing frequency is high.

Comparative example 1A: method for treating waste mother liquor in terramycin production by using intensified hydrolysis-AnMBR technology (without using dynamic composite membrane)

Except that the speed of biogas aeration in the step 2) is kept at 2L/min; the pressure difference across the membrane was the same as that in comparative example 1 except that the initial pressure difference was-1.31 kPa.

Measuring COD of inlet water and outlet water of the AnMBR; the pH of the effluent, the content of volatile fatty acids, the methane yield, the membrane working/rest time, the transmembrane pressure difference and the first membrane wash cycle were determined and the results are shown in tables 1 and 2.

When the oxytetracycline production wastewater is treated, compared with the 'enhanced hydrolysis-AnMBR' adopting a microorganism dynamic composite membrane in the method, the effluent quality of the conventional 'enhanced hydrolysis-AnMBR' is similar, but the membrane pollution is serious, and the membrane washing frequency is high.

Comparative example 1B: method for treating waste mother liquor in terramycin production by using intensified hydrolysis-UASB technology

The anaerobic treatment process is the same as the example 1 except that the anaerobic treatment process is changed from AnMBR to UASB, namely, the hydrolysis-enhanced wastewater is directly injected into an up-flow anaerobic sludge bed (UASB) with the effective volume of 3L by a peristaltic pump to carry out anaerobic sludge treatment on the wastewater, wherein the water inlet flow rate is 0.23L/d, 0.31L/d and 0.46L/d; the ascending flow rates are respectively 0.10m/h, 0.13m/h and 0.20 m/h; the anaerobic biological treatment temperature is 35 ℃ (usually 30-40 ℃); the alkalinity of inlet water is 1800 mg/L;

measuring COD of the UASB inlet water and the UASB outlet water; the pH of the effluent, the content of volatile fatty acids, and the methane yield were measured, and the measurement results are shown in Table 3.

TABLE 3 UASB effluent quality measurement results in control example 1B

The UASB reactor is a small-scale reactor, the effective volume is 3L, the operation temperature is preferably 35 ℃ (usually 30-40 ℃), a peristaltic pump is adopted for continuous water injection, the load of the reactor is increased in a gradient manner by adjusting the water inlet volume, and the removal rate of COD under different loads is explored. The corresponding removal rates were calculated by recording the COD of the influent and effluent water during the run, and the stability of the system was assessed by the results of measuring the effluent pH and volatile fatty acids.

Long-term continuous operation experiments prove that the UASB can stably operate under the condition that the operation load is less than or equal to 2gCOD/L/d (namely the inflow water flow is 0.31L/d), the COD removal rate reaches 50.11 percent under the condition that the load is 2gCOD/L/d (namely the inflow water flow is 0.31L/d), the daily COD removal rate fluctuation is not large, the effluent pH is more than 7, the effluent volatile fatty acid content is lower than 500mg/L, the methane yield accords with the yield calculated theoretically, and the UASB can be kept stable at the moment. However, when the amount of the inlet water is increased and the load is increased to 2.5g COD/L/d (i.e. the inlet water flow is 0.46L/d), the COD removal rate of the UASB reactor is remarkably reduced to about 20%, the pH of the outlet water is remarkably reduced, and the volatile acid is more than 2000mg/L, so that the treatment effect and the stability of the system are deteriorated.

The effect of enhanced hydrolysis-UASB is mainly determined by two parameters, one load and the other COD removal rate. The higher the load, the higher the removal rate, indicating the better the treatment effect. The load is the amount of COD (i.e. water amount) treated per unit volume and time, and the removal rate is the percentage of COD removed, and the higher the percentage is, the better the quality of the effluent is.

For UASB, generally 5-10 gCOD/L/d can be used as high load, while less than 3gCOD/L/d is low load. On the premise of ensuring that the removal rate is more than 50%, the treatment load which can be reached by the reactor is compared, and at the moment, the higher the load is, the stronger the treatment capacity is, and the better the process is.

When the oxytetracycline production wastewater is treated, compared with the method of the invention, namely 'enhanced hydrolysis-AnMBR', the 'enhanced hydrolysis-UASB' can only stably operate under lower load, and the COD removal rate is lower.

Example 2-2B; comparative example 2-2B will be described with reference to an example of treating erythromycin formation wastewater. The production of the erythromycin comprises the processes of fermentation and extraction, the residual bacterial liquid is filtered by a plate frame to obtain the erythromycin production waste mother liquor, the erythromycin production waste mother liquor has high bacteriostatic ability and can not be directly subjected to biological treatment, and the COD of the mother liquor is about 5000-8000 mg/L; a pH of about 7.0; the concentration of the erythromycin is 200-280 mg/L, and the concentration of the suspended matters is 300-400 mg/L.

In the examples, the waste mother liquor COD of erythromycin production is 8000mg/L, pH is 7.0, erythromycin concentration is 200mg/L, and suspended matter concentration is 350 mg/L. It should be noted that the data of the wastewater treatment process, particularly anaerobic treatment, are shown by calculating the average value since a large number of data are accumulated by reflecting the effect of long-term stable operation.

In the examples, an anaerobic membrane bioreactor (AnMBR) is described by taking a split-type membrane-embedded reactor as an example, wherein a hollow fiber membrane is taken as an example for a filtration membrane. The filtering membrane can also be a flat membrane, and the AnMBR can also be an integral type. Parameters of the hollow fiber membranes used in examples 1 to 1B, comparative examples 1 and 1A: the pore diameter of the membrane is 0.1 μm (usually 0.1-0.4 μm, preferably 0.1 μm); the membrane area was 0.1m²。

Example 2: method for treating erythromycin production wastewater by using intensified hydrolysis-AnMBR technology

1. Enhanced hydrolysis

1-1, heating the erythromycin production waste mother liquor, and preheating the waste mother liquor to enable the temperature of the waste mother liquor to rise to 60 ℃ (usually 40-60 ℃); then, heating the mixed solution until the temperature of the erythromycin waste mother liquor rises and is kept at 110 ℃ (usually 85-160 ℃), and carrying out intensified hydrolysis treatment on the waste mother liquor at the temperature of 110 ℃ (usually 85-160 ℃), wherein the intensified hydrolysis treatment time is 0.8h (usually 0.5-6 h);

1-2, after the intensified hydrolysis is carried out for 0.8h, the wastewater is subjected to gradual heat exchange, and is cooled to 35 ℃ (usually 30-40 ℃) so as to meet the requirement of medium-temperature anaerobic treatment, and the intensified hydrolysis wastewater is obtained.

The water quality determination result of the reinforced hydrolysis wastewater is as follows: the residual concentration of the erythromycin in the reinforced hydrolysis wastewater is 0.8mg/L and less than 1 mg/L; the concentration of suspended matters is 1300mg/L, and the concentration of suspended matters is 600-1500 mg/L; the pH value of the intensified hydrolyzed wastewater is 7 (usually 5-7); the alkalinity is 2300 mg/L; the COD was 7500 mg/L.

2. Pretreatment of AnMBR

Same as in step 2 of example 1.

3. AnMBR treatment

Adopt the peristaltic pump to carry out continuous water injection in the anaerobic membrane bioreactor that effective volume is 8L with the waste water of will strengthening hydrolysising, the intermittent type goes out water, carries out anaerobism biological treatment to the erythromycin waste water of strengthening hydrolysising, wherein:

through adjusting the inflow, adjust organic load and the protein granule load that gets into in the AnMBR, wherein, the inflow is respectively: 2.1L/d, 4.3L/d, 6.4L/d, 8.5L/d; the anaerobic biological treatment temperature is 35 ℃ (usually 30-40 ℃); the aeration flow rate of the biogas is kept at 1L/min (usually 0.5-3L/min); the flux of the membrane is controlled to be 12LMH (usually 4-20 LMH); AnMBR intermittently discharges water, namely the operation mode of the membrane is selected to be intermittent operation, the operation is carried out for 3 minutes, the rest time is changed along with the change of the inflow water, and the operation and the rest time of the membrane are shown in a table 6.

According to the inflow, the organic load of anaerobic biological treatment of AnMBR is calculated to be 2, 4, 6 and 8gCOD/L/d respectively according to the formula (1):

organic load ═ C Q/V (1)

Wherein: in equation (1): c: COD concentration (g/L) of inlet water; q: flow rate (L/d); v: AnMBR reactor effective volume (L). The unit is gCOD/L/d.

The feed water has a pH of 7 (generally 6 to 8, preferably 6.5 to 7); the alkalinity of the feed water is 2300mg/L (usually 1000-3000 mg/L, preferably 2000-3000 mg /). The concentration of the sludge in the reactor is 20g/L (usually 10-25 g/L, preferably 15-20 g/L).

And monitoring transmembrane pressure difference (TMP) of the filter membrane in real time during the anaerobic biological treatment process, and taking the maximum value of the transmembrane pressure difference when the membrane is at rest at each stage, wherein the initial transmembrane pressure difference is-5.55 kPa. (ii) a Monitoring the COD, pH and concentration of volatile fatty acids of the AnMBR effluent; measuring the methane yield in the anaerobic biological treatment process; calculating the COD removal rate of the wastewater treated by the AnMBR; the results are shown in Table 5.

TABLE 5 AnMBR effluent quality measurement results in examples 2-2B and comparative examples 2 and 2A

Table 6 operating results of AnMBR membrane modules in examples 2-2B and comparative example 2

The erythromycin production waste mother liquor subjected to the enhanced hydrolysis treatment removes the inhibition of antibiotics on anaerobic biological treatment, and better treatment efficiency and operation load can be realized through the high-efficiency AnMBR reactor.

The methane yield in the wastewater treatment process of the method accords with the yield calculated theoretically, which shows that the method can ensure the stability of the anaerobic biological treatment system of the fermentation pharmaceutical wastewater; and the COD removal efficiency of the wastewater is high, the wastewater treatment load is high, the treatment efficiency is far higher than that of the existing engineering system and the pilot plant test at present, the wastewater treatment capacity is high, the production process is allowed to increase the yield, and the wastewater treatment cost is reduced.

The load of the reactor was adjusted by adjusting the volume of the influent water, the removal rate was calculated by recording the COD of the influent and effluent water during the run, and the stability of the system was evaluated by the results of measuring the pH of the effluent water and the volatile fatty acids.

Experiments prove that the AnMBR can stably run when the processing load is 2-6 gCOD/L/d, and the COD removal rate is high. Under the condition that the load is 6gCOD/L/d, the removal rate reaches more than 50 percent, the daily COD removal rate fluctuation is not large, the pH value of effluent is more than 7, the content of volatile fatty acid in the effluent is lower than 500mg/L, and the yield of methane accords with the yield calculated by theory. When the organic load is increased to 8gCOD/L/d, the COD removal rate is obviously reduced to 35.56 percent, the content of the volatile acid in the effluent exceeds 1000mg/L, and the anaerobic treatment effect is not stable any more.

It is worth noting that in the application of AnMBR, two key factors need to be considered, one is the efficiency of anaerobic biological treatment, which is reflected in indexes such as organic load and COD removal rate; another is membrane sustainability, which is manifested by a pressure differential across the membrane, with a greater pressure differential across the membrane indicating greater membrane fouling. The pressure difference across the membrane should generally be greater than-40 kPa, preferably greater than-30 kPa. The transmembrane pressure difference reflects the pressure required for maintaining the membrane to discharge water, and directly influences the membrane washing frequency. When the load is 6gCOD/L/d, the membrane washing frequency is 52 days/time. When the load is further increased to 8gCOD/L/d, the first membrane washing period is rapidly increased to 43 days/time.

According to the results of tables 5 and 6, the COD removal rate at the organic load of 6gCOD/L/d exceeds 50%, and the membrane washing frequency is 52 days/time, which shows that the control of membrane pollution is better. In combination with the aspects of load and membrane pollution control, when the hydrolysis-enhanced AnMBR is used for treating the erythromycin fermentation waste mother liquor, the organic load should be controlled to be 6 gCOD/L/d.

Example 2A: method for treating waste mother liquor of fermentation erythromycin production by using intensified hydrolysis-AnMBR technology

1. Enhanced hydrolysis

Same as in step 1 of example 2.

2. Pretreatment of AnMBR

The procedure was carried out in the same manner as in 2. sup.nd step (2) of example 2, except that the flow rate of aeration of biogas was 2L/min and the thickness of the microbial film uniformly supported on the surface of the filtration membrane was 1.0 mm.

3. AnMBR treatment

The procedure was as in step 3 of example 2, except that the initial transmembrane pressure difference of the filtration membrane was-3.72 kPa. Measuring COD of inlet water and outlet water of the AnMBR; the pH of the effluent, the content of volatile fatty acids, the methane yield, the membrane working/resting time, the transmembrane pressure difference and the first membrane washing period were measured, and the results are shown in tables 5 and 6.

Example 2B: method for treating waste mother liquor of fermentation erythromycin production by using intensified hydrolysis-AnMBR technology

1. Enhanced hydrolysis

Same as in step 1 of example 2.

2. Pretreatment of AnMBR

The procedure was carried out in the same manner as in step 2 of example 2 except that the flow rate of aeration of biogas was 0.5L/min and the thickness of the microbial membrane uniformly supported on the surface of the filtration membrane was 2.0 mm.

3. AnMBR treatment

The procedure was as in step 3 of example 2, except that the initial transmembrane pressure difference of the filtration membrane was-8.67 kPa. Measuring COD of inlet water and outlet water of the AnMBR; the pH of the effluent, the content of volatile fatty acids, the methane yield, the membrane working/resting time, the transmembrane pressure difference and the first membrane washing period were measured, and the results are shown in tables 5 and 6.

Combining the results of examples 2-2B, the anaerobic treatment effect of each example was similar for the AnMBR treatment effect, i.e., from the viewpoint of organic loading and COD removal rate. From the aspect of membrane pollution control, the three embodiments can keep a longer membrane washing period under higher organic load, which shows that the dynamic composite membrane process formed by the microbial membrane loaded on the surface of the filtering membrane and the filtering membrane in the step 2) is feasible and obvious in treatment effect when applied to a system for treating fermentation pharmaceutical wastewater by AnMBR. Comparative examples 2 to 2B show that the effect is best when the thickness of the dynamic membrane of microorganisms is controlled to 1.5 mm. This is because the dynamic membrane of the microorganism cannot function to retain protein particles at a low thickness. When the thickness is too high, the microorganisms themselves become a limiting parameter for the operation of the membrane.

Comparative example 2:

1. enhanced hydrolysis

Same as in step 1 of example 2.

2. AnMBR treatment

The procedure of step 3 in example 2 was repeated, except that the hydrolysis-enhanced wastewater was continuously injected directly into the AnMBR, the aeration rate of the biogas was maintained at 4L/min, and the initial transmembrane pressure difference of the filtration membrane was-1.48 kPa. The comparative example 2 is different from the example 2 in that the microorganism dynamic membrane is not supported on the surface of the filtration membrane before the anaerobic membrane biological treatment, i.e., the microorganism dynamic membrane is not formed.

Measuring COD of inlet water and outlet water of the AnMBR; the pH of the effluent, the volatile fatty acid content, the methane production, the membrane working/rest time, the transmembrane pressure difference and the first membrane wash cycle were determined and the results are shown in tables 5 and 6.

Comparing the results of comparative example 2 with examples 2-2B, although comparative example 2 was not significantly different from examples 2-2B in the load and removal rate of AnMBR, there was a large difference in the membrane washing frequency. The membrane washing frequency of comparative example 2 was much higher than that of example 2-2B, because the protein particles blocked the membrane pores and became a major contributor to membrane fouling. Meanwhile, the application of the dynamic composite membrane can greatly improve the operation effect of the membrane, reduce the membrane washing frequency and prolong the membrane washing period.

When the oxytetracycline production wastewater is treated, compared with the 'intensified hydrolysis-AnMBR' adopting a dynamic composite membrane, the conventional 'intensified hydrolysis-AnMBR' has the more serious membrane pollution and the higher membrane washing frequency.

Comparative example 2A:

except that the speed of biogas aeration in the step 2) is kept at 2L/min; the pressure difference across the membrane was initially-1.37 kPa, and the same as in comparative example 2.

Measuring COD of inlet water and outlet water of the AnMBR; the pH of the effluent, the volatile fatty acid content, the methane production, the membrane working/rest time, the transmembrane pressure difference and the first membrane wash cycle were determined and the results are shown in tables 5 and 6.

Comparative example 2B: method for treating waste mother liquor in erythromycin production by using intensified hydrolysis-UASB technology

The anaerobic treatment was performed in the same manner as in example 2 except that the anaerobic treatment was carried out by replacing the AnMBR with the UASB, namely, the hydrolysis-enhanced wastewater after the hydrolysis-enhanced treatment was directly subjected to continuous water injection into an Upflow Anaerobic Sludge Blanket (UASB) having an effective volume of 3L by means of a peristaltic pump, and the wastewater was subjected to anaerobic sludge treatment, wherein the inflow rate was 0.38L/d, 0.75L/d, and 1.13L/d; the ascending flow rates are respectively 0.1m/h, 0.2m/h and 0.3 m/h; the anaerobic biological treatment temperature is 35 ℃ (usually 30-40 ℃);

measuring COD of the UASB inlet water and the UASB outlet water; the pH of the effluent, the content of volatile fatty acids, and the methane yield were measured, and the measurement results are shown in Table 7.

TABLE 7 UASB effluent quality measurement results in control example 2A

Inflow (L/d)	0.38	0.75	1.13
				Treatment load (gCOD/L/d)	1.0	2.0	3.0
Water COD (mg/L)	8000	8000	8000
				COD of effluent (mg/L)	4238	4658	6054
COD removal Rate (%)	47.02	41.78	24.33
				pH of the effluent	7.31	7.24	6.82
Volatile fatty acid content (mg/L)	412	506	1174
				Methane yield (L/d)	0.43	0.75	0.66

When the erythromycin production wastewater is treated, the 'enhanced hydrolysis-UASB' method can only stably operate under lower load, and the COD removal rate is low.

The inflow is increased, the treatment load is more than 3.0gCOD/L/d, the UASB reactor can not stably operate for a long time, the removal rate of COD is obviously reduced and is reduced from more than 40 percent to about 24 percent; the pH fluctuation of the effluent is large and is obviously reduced to below 7; the content of volatile acid is more than 1000 mg/L; the methane yield is reduced to only 0.66L/d; the processing system is crashed, and the processing effect and the stability are poor; the system has the phenomenon of sludge loss.

The UASB reactor that is used for as the comparison in this patent is the reactor of a lab scale, and effective volume 3L, operating temperature preferred 35 ℃ (is 34 ~ 36 ℃ usually), adopts the peristaltic pump to carry out continuous water injection, improves the load of reactor through adjusting into the volume of intaking and coming the gradient to explore the clearance of COD under its different loads. The load of the reactor was adjusted by adjusting the volume of the influent water, the removal rate was calculated by recording the COD of the influent and effluent water during the run, and the stability of the system was evaluated by the results of measuring the pH of the effluent water and volatile fatty acids.

Long-term continuous operation experiments prove that the removal rate of the UASB is about 41 percent under the condition that the load is 2gCOD/L/d, the fluctuation of the COD removal rate per day is small, the pH value of effluent is more than 7, the content of volatile fatty acid in the effluent is less than 500mg/L, the methane yield accords with the yield calculated by theory, and the UASB can stably operate at the moment. When the load of the reactor is further improved to 3gCOD/L/d by increasing the inflow rate, the COD removal rate of the UASB reactor is remarkably reduced to about 25 percent, the pH value of the effluent is reduced, the volatile acid is more than 1000mg/L, and the treatment effect and the stability of the system are deteriorated at the moment.

Claims (10)

1. A combined treatment method for fermented antibiotic pharmaceutical wastewater is characterized by sequentially carrying out intensified hydrolysis treatment on the pharmaceutical wastewater and carrying out anaerobic biological treatment by using an anaerobic membrane bioreactor.

2. The method as set forth in claim 1, wherein the intensified hydrolysis treatment is a hydrolysis treatment of the antibiotic pharmaceutical wastewater under heating conditions to destroy the pharmacodynamic functional groups of the antibiotic, thereby inactivating the antibiotic in the wastewater to inhibit the bacteriostatic activity of the antibiotic and improving the biodegradability of the wastewater.

3. The method according to claim 2, wherein the temperature of the intensified hydrolysis treatment is 85 to 160 ℃, preferably 100 to 160 ℃; the time for the intensified hydrolysis treatment is 0.5 to 6 hours, preferably 1 to 2 hours.

4. A method according to any one of claims 1 to 3, wherein the anaerobic biological treatment using the anaerobic membrane bioreactor is carried out at a temperature of 30 to 60 ℃, preferably 35 to 55 ℃.

5. A method according to any one of claims 1 to 3, wherein the sludge concentration in the anaerobic membrane bioreactor during the anaerobic biological treatment is 10 to 25g/L, preferably 15 to 20 g/L.

6. A method according to any one of claims 1 to 3, wherein the anaerobic biological treatment process is carried out under a control load of 4gCOD/L/d, preferably 5 to 10gCOD/L/d, more preferably 5 to 6 gCOD/L/d.

7. The method as set forth in any one of claims 1 to 3, wherein the pore size of the filtration membrane of the anaerobic membrane bioreactor is 0.1 to 0.4 μm.

8. The method as claimed in any one of claims 1 to 3, wherein in the anaerobic biological treatment process by using the anaerobic membrane bioreactor, the alkalinity of the wastewater entering the anaerobic membrane bioreactor is controlled to be less than or equal to 3500mg/L, preferably 1000-3000 mg/L, and more preferably 2000-3000 mg/L.

9. The method as set forth in claim 1, wherein before the anaerobic biological treatment, the method further comprises pretreating the anaerobic membrane bioreactor so that a dynamic microorganism layer is loaded on the surface of a filter membrane of the anaerobic membrane bioreactor, and the loaded dynamic microorganism membrane and the filter membrane form a dynamic microorganism composite membrane.

10. The method of claim 9, wherein said pre-processing comprises the steps of:

A) preparing a pre-treatment nutrient solution

Adding glucose and soybean peptone serving as substrates into sterile water to prepare a nutrient solution, adding a phosphate buffer solution, and adjusting the pH value of the nutrient solution to 6.5-7.5;

B) closing a biogas aeration pump of the AnMBR, injecting anaerobic sludge into the AnMBR, and introducing nitrogen at the same time until the oxygen in the reactor is emptied;

C) starting a water outlet pump of the AnMBR, pumping water outwards, monitoring transmembrane pressure difference of a filter membrane of the AnMBR, starting a biogas aeration pump of the AnMBR until the transmembrane pressure difference of the filter membrane reaches below-10 kPa, stopping pumping water until the transmembrane pressure difference is constant to be-3 to-9 kPa, and uniformly loading a microbial layer on the surface of the filter membrane of the AnMBR.

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