CN101913706B - Method for treating monosodium glutamate wastewater with three-phase biological fluidized bed reactor - Google Patents

Abstract

The present invention relates to a method for treating monosodium glutamate wastewater by a three-phase biological fluidized bed reactor, the method comprising the following steps: fixing domesticated aerobic nitrifying and denitrifying bacteria on a carrier of a three-phase biological fluidized bed, the bacterial concentration in the reactor being 6.0-8.0 g/L; wherein the liquid level in the three-phase separator of the three-phase biological fluidized bed reactor is 150-300 mm, the ratio of the height to the diameter of the outer cylinder is 6-13, and the bottom gap height is 60-70 mm; adjusting the concentration of monosodium glutamate production wastewater to make COD _Cr lower than 1600 mg and ammonia nitrogen lower than 160 mg; sending the monosodium glutamate production wastewater into the three-phase biological fluidized bed reactor by a peristaltic pump, the hydraulic retention time of the influent water is 2-7 hours, turning on the air compressor to aerate the reactor, and the air flow rate is controlled at 0.3-0.4 m ³ /h. The method optimizes the process conditions for treating monosodium glutamate wastewater by a three-phase biological fluidized bed method, and can effectively improve the removal rate of COD and ammonia nitrogen.

Description

Method for treating monosodium glutamate wastewater with three-phase biological fluidized bed reactor

technical field

The invention relates to a sewage biological treatment technology, in particular to a method for treating monosodium glutamate waste water with a three-phase biological fluidized bed reactor.

Background technique

In recent years, my country's monosodium glutamate industry has developed rapidly. The production of monosodium glutamate is increasing at a rate of 10% per year. Restricting factors for the survival and development of the industry. Due to the characteristics of high suspended matter content, high BOD ₅ , high COD _Cr , high NH ₃ -N, high Cl ^- and strong acidity of MSG production wastewater, it is very difficult to treat it. At present, the pollution load of monosodium glutamate wastewater has been greatly reduced by adopting processes such as extracting yeast from fermentation waste liquid, evaporating high-concentration waste liquid to produce compound fertilizer, and high-temperature continuous isoelectric extraction of glutamic acid, but the concentration of COD and ammonia nitrogen in the integrated waste water of monosodium glutamate production Still as high as 2000mg/L and 200mg/L respectively, further treatment is still required before discharge.

Biological treatment is the most effective and economical way and method to deal with organic pollutants today. The BOD ₅ /COD _Cr of the comprehensive waste water from monosodium glutamate production is greater than 0.3, which has good biodegradability and is easy to biodegrade. The biological treatment methods of monosodium glutamate wastewater mainly include aerobic biological treatment, anaerobic biological treatment, and algae symbiosis treatment. Aerobic biological treatment technologies include: activated sludge method and biological contact oxidation method (Tao Tao, Zhan Dehao, Lu Xiuqing, etc., the status and progress of monosodium glutamate wastewater treatment [J], Environmental Pollution Treatment Technology and Equipment, 2002, 3(1): 69 ~72).

The activated sludge method is based on activated sludge suspended in water, which is fully contacted with sewage under environmental conditions that are conducive to the growth of microorganisms. The activated sludge process commonly used in the treatment of monosodium glutamate wastewater is the sequencing batch activated sludge process, and the main device is the sequencing batch reactor (sequencing batch reactor), referred to as the SBR process. The SBR method has the characteristics of simple process, flexible operation, high degree of automation, high sludge concentration, concentration gradient during the reaction period, and can speed up the reaction speed and inhibit the expansion of sludge filamentous bacteria. Its core equipment is a sequencing batch batch reactor. The process flow is shown in Figure 1. The entire operation cycle of SBR consists of five basic processes: water inflow, reaction, precipitation, water outflow, and idle. The reactors of the equipment are carried out sequentially, and corresponding operations can be selected according to different treatment purposes. BOD removal, nitrification, and phosphorus absorption can be realized by controlling the aeration time, and the reactor can be maintained well by controlling the aeration or stirring intensity. Oxygen, anaerobic or anoxic state, realize nitrification and denitrification process (Zhang Tong, Intermittent activated sludge process sewage treatment technology and engineering application, Chemical Industry Press, 2002: 3-28; Wang Chuang, Yang Haizhen, Gu Guowei, Experimental Research on Improved Sequencing Batch Reactor (MSBR), China Water and Wastewater, 2003, 19(5): 41~43). The actual operation results show that it is possible for this process to realize biological nitrogen removal during treatment (Andreottoia G, Foladori P, Ragazzi M.On-line Control of a SBR System for Nitrogen Removel from Industrial Wastewater.Wat.Sci.Tech.2001, 43 (3): 93~100).

The biological contact oxidation method is also called the submerged biological filter, which is to set the filler in the reactor, and the wastewater is purified under the action of the biofilm at the junction of the oxygenated wastewater and the filler covered with biofilm. In the initial stage of operation of the biological contact oxidation method, a small amount of bacteria adhere to the surface of the filler, and a thin biofilm is gradually formed due to the reproduction of bacteria. Under the condition of sufficient dissolved oxygen and food, the reproduction of microorganisms is very rapid, and the biofilm gradually thickens. Dissolved oxygen and organic matter in sewage are utilized by microorganisms by virtue of diffusion. But when the biofilm reaches a certain thickness, oxygen can no longer diffuse to the inner layer of the biofilm, and the aerobic bacteria die, while facultative bacteria and anaerobic bacteria begin to multiply in the inner layer, forming an anaerobic layer, using the dead aerobic bacteria as Substrate, and anaerobic bacteria continue to develop on this basis. After a period of time, the number began to decline, and the release of metabolic gas products caused the inner biofilm to fall off in large quantities. On the surface of the filler where the biofilm has been shed, a new biofilm has re-developed. In the contact oxidation tank, due to the large surface area of the filler, every stage of biofilm development exists simultaneously, which stabilizes the ability to remove organic matter at a certain level. The biofilm has a three-dimensional structure in the pool, which is beneficial to maintain a stable processing capacity.

The biological contact oxidation method combines the characteristics of the activated sludge method and the biological filter method, and its technical characteristics include:

(1) The high volume load is not limited by the return sludge, and the concentration of biofilm is relatively high, generally up to about 10g/L, while the sludge concentration of ordinary activated sludge method is 2-3g/L. Due to the large amount of biomass per unit volume, the organic load of the volume is also increased.

(2) The processing time is short, the investment cost is reduced, and the occupied area is reduced.

(3) Strong impact load resistance The biofilm composed of microbial groups adheres to the surface of the filler, and has strong impact resistance to water overload operation, and the biofilm is less affected and recovers quickly.

(4) Less sludge output The biofilm sludge discharged from the final sedimentation tank is very little, accounting for about 0.1% of the non-water flow, the average moisture content of the sludge is 96.7%, and the sludge produced by removing 1kg of COD is 0.37-0.42kg, compared with The amount of sludge produced by the activated sludge method is 1/3 less.

(5) Easy to cultivate and domesticate.

(6) Simple management The plug-flow biological contact oxidation method does not require sludge return equipment, and there is no sludge bulking that is likely to occur in the activated sludge process during operation, so the operation is relatively simple.

The disadvantage of this technology for treating monosodium glutamate wastewater is that the residence time of wastewater is long and the volume load is low.

Internal-Circulation Three-Phase Bio-Fluidized Bed (ITFB for short) is a wastewater biochemical treatment technology developed in the past 10 years. It uses smaller particles such as sand, activated carbon, and coke as carriers. Filled in the bed, the surface of the carrier is covered with biofilm, and the sewage flows from bottom to top at a certain flow rate, making the carrier in a fluidized state, while removing and degrading organic pollutants. As shown in FIG. 2 , the reactor is mainly composed of an aeration zone 11 , a reaction zone 12 , a separation zone 13 and a reflux zone 14 . The reaction zone is composed of a concentric inner cylinder and an outer cylinder. The carrier is filled in the reactor. The microporous aeration device is installed at the bottom of the inner cylinder. When the compressed air is released from the aeration device into the inner cylinder (upflow cylinder), Due to the propulsion of the gas and the entrainment and mixing of compressed air in the water, the density of the mixture of water and carrier decreases and flows upward. After reaching the top of the separation zone 13, the large bubbles escape, while the mixture of water and carrier containing small bubbles Then it flows into the outer cylinder (downflow cylinder), and the density increases due to the relative decrease in the gas content of the outer cylinder. Therefore, the mixed liquid flows upwards in the inner cylinder, and flows downwards in the outer cylinder to form an internal cycle. The density difference between the inner and outer cylinders is positive is the driving force of circulating fluidization.

The internal circulation three-phase biological fluidized bed has the following advantages:

Small-diameter solid particles are used as the carrier, and the carrier is in a fluidized state in the bed, so its surface area per unit volume is much larger than other biofilm methods.

Because the carrier is in a circulating fluidized state, the relative movement between microorganisms and wastewater is greatly accelerated, and the mass transfer effect is enhanced. At the same time, the thickness of the biofilm can be effectively controlled to maintain a high biological activity, and the sewage is treated. After separation and settlement in the settlement area, it is discharged through the outlet weir.

The huge specific surface area of the biological fluidized bed makes the biomass of the unit bed body very high, coupled with the fast mass transfer speed, once the wastewater enters the bed, it is quickly mixed and diluted, so the impact load resistance of the biological fluidized bed is strong. The volume load is also higher than other biological treatment methods. Therefore, under the same influent concentration, using biological fluidized bed technology to treat sewage can greatly reduce the volume of the device, thereby significantly reducing project investment and land occupation area.

Due to the continuous collision and friction of biological particles in the bed, the thickness of the biofilm is relatively thin, generally less than 0.12 μm, and relatively uniform. For the same type of wastewater, under the same treatment conditions, the respiration rate of the biofilm is about twice that of the activated sludge. It can be seen that the reaction rate is fast, the activity of microorganisms is high, and the microorganisms brought out of the system are less, and the sludge can be recycled. The amount and regenerated biomass is small, the system will not be blocked due to the accumulation of biomass, the liquid-solid contact area is large, and the three-phase separation is easy.

At present, there is no report on the application of three-phase biological fluidized bed technology to the treatment of MSG wastewater. According to the characteristics of high ammonia nitrogen in MSG wastewater, the application technology of three-phase biological fluidized bed in the purification of MSG wastewater needs to be further improved.

Contents of the invention

The purpose of the present invention is to overcome the deficiency of existing monosodium glutamate production wastewater treatment technology, and provide a kind of treatment method of high concentration monosodium glutamate wastewater with high biochemical efficiency, low energy consumption, low investment and operation cost.

To achieve the above object, the present invention adopts the following technical solutions:

A method for treating monosodium glutamate waste water with a three-phase biological fluidized bed reactor, the method may further comprise the steps:

The domesticated aerobic nitrification and denitrification bacteria are fixed on the carrier of the three-phase biological fluidized bed, and the concentration of the bacteria in the reactor is 6.0-8.0g/L; the height of the outer cylinder of the three-phase biological fluidized bed reactor is the same as The diameter ratio is 6-13, and the bottom gap height is 60-70mm;

Adjust the concentration of monosodium glutamate production wastewater so that COD _Cr is lower than 1600mg and ammonia nitrogen is lower than 160mg; the monosodium glutamate production wastewater is sent into the three-phase biological fluidized bed reactor by the peristaltic pump, and the three phases are separated in the three-phase biological fluidized bed reactor The height from the bottom of the reactor to the liquid surface is 150-300mm, the hydraulic retention time of the influent is 2-7 hours, the air compressor is turned on to aerate the reactor, and the air flow rate is controlled at 0.3-0.4m ³ /h.

The above-mentioned method, wherein, before the above-mentioned steps, can also include the domestication step of aerobic nitrification and denitrification bacteria:

A. The monosodium glutamate wastewater with about 200 mg of COD _Cr and about 20 mg of ammonia nitrogen is sent into the three-phase biological fluidized bed reactor equipped with a carrier by a peristaltic pump, and the liquid level is below the overflow weir to stop the water intake;

B. Turn on the air compressor to aerate the reactor, the air flow rate is controlled at 0.3 ~ 0.4m ³ /h; the activated sludge obtained from the reaction tank of the monosodium glutamate sewage treatment plant is added to the reactor, and the concentration of mixed microorganisms in the system is 1.0 ~ 1.5g/L; add buffer to adjust the pH value of the water to 7 ~ 8, the temperature is 20 ~ 30 ℃, and the exposure is 24 ~ 48h;

C. Then discharge all the floating mud, and the reactor starts to continuously feed MSG waste water, and the hydraulic retention time of the feed water is 2 hours; in the first 1 to 15 days, the concentration of the feed water is controlled at about 200 mg of COD _Cr and about 20 mg of ammonia nitrogen, and then In 60-90 days, the influent concentration gradually increased to about 1600mg of COD _Cr and about 160mg of ammonia nitrogen.

The above method, wherein the aspect ratio is preferably 10, the liquid level height is preferably 250 mm, and the bottom gap height is preferably 63 mm.

The above-mentioned method, wherein, the total effective volume of the fluidized bed reactor is preferably 25-30L; the total height of the reactor is preferably 2800-3200mm; the height of the reaction zone is preferably 1800-2200mm, and the diameter of the reactor is preferably 130-170mm , The height of the inner cylinder is preferably 1800-2200mm, and the diameter of the inner cylinder is preferably 80-120mm.

The above method, wherein, the carrier preferably accounts for 5%-8% of the effective volume of the reactor.

The above-mentioned method, wherein, the particle size of the carrier is preferably 0.3-0.45 mm.

The above method, wherein the carrier can be ground ceramsite or volcanic rock.

The beneficial effects of the present invention are: the present invention has studied several main equipment and process parameters that affect the purification effect of monosodium glutamate production wastewater by the three-phase biological fluidized bed method, optimized the process conditions, and can effectively improve the removal rate of COD and ammonia nitrogen, The COD removal load reached 10.46 (kg/m ³ ·d), and the ammonia nitrogen removal load reached 0.966 (kg/m ³ ·d).

Description of drawings

Figure 1 is a flow chart of the sequencing batch activated sludge process.

Fig. 2 is a schematic flow diagram of the three-phase biological fluidized bed reactor according to the present invention.

Fig. 3 is the process flow chart of denitrification in Comparative Example 1.

Detailed ways

Aiming at the characteristics of monosodium glutamate production wastewater, the invention improves the three-phase biological fluidized bed wastewater purification process, and determines the optimal reactor structure parameters and process parameters for the three-phase biological fluidized bed purification of monosodium glutamate production wastewater.

① The influence trend of height-to-diameter ratio versus cycle time is consistent, that is, with the increase of height-to-diameter ratio, there is a minimum value of specific cycle time, and the lowest specific cycle time is found at the height-to-diameter ratio of 10, that is, the highest cycle speed . It can also be confirmed that this effect of aspect ratio versus cycle time is independent of changes in liquid level and bottom clearance height. However, the degree of influence of the height-to-diameter ratio on the cycle time is different under different surface gas velocities. When the surface gas velocity is small, the specific cycle time changes greatly with the increase of the height-to-diameter ratio; with the increase of the surface gas velocity, Reduced effect of aspect ratio versus cycle time.

Therefore, if the carrier that is difficult to fluidize is selected, determining the height-diameter ratio of the reactor to be 10 can make the carrier easier to achieve circulating fluidization. The circulation rate of the liquid directly affects the mixing degree of the liquid, the gas holdup rate and the total mass transfer coefficient of oxygen volume, and the liquid circulation rate has nothing to do with the liquid level height, so when studying the influence of the height-diameter ratio on other properties of the reactor, maintain the reaction The height of the liquid level in the reactor remains unchanged, which is 250mm (reactor design value), and the height of the bottom gap is directly related to the degree of liquid turbulence at the bottom of the reactor, which has a significant impact on liquid mixing and oxygen mass transfer.

② The height of the bottom gap (that is, the distance between the bottom of the inner cylinder and the aeration plate) has a significant impact on the mixing of the reactor. When the liquid level height is 250mm, the influence trend of the bottom gap height versus mixing time under different height-to-diameter ratios is consistent. When the bottom gap height is 38mm, it has the largest specific mixing time, and the mixing performance of the reactor is the worst. The height of 21mm has a very short specific mixing time. The reason may be that the liquid at the height of the bottom gap enters the upflow region from the downflow area through the bottom gap. When the bottom gap is small, the liquid flow rate increases sharply, and violent turbulence occurs, which strengthens the mixing of fluids; when the bottom gap is large, The fluid still flows through the bottom of the reactor in a plug flow state, and the mixing is poor; when the bottom gap is large, the flow rate decreases sharply, which is also conducive to the mixing of the fluid to a certain extent. Therefore, the fluid flows from the downflow zone through the bottom of the reactor, and the change of the flow rate is the main reason for determining the mixing quality of the reactor.

When the height of the liquid level is 250mm, when the height of the reaction zone is 100cm, the oxygen mass transfer coefficient K _La decreases with the increase of the bottom gap height; when the height of the reaction zone is 150cm, K _La increases with the increase of the bottom gap height; When the height of the reaction zone is 200cm, the trend of K _La increasing with the height of the bottom gap is more obvious. It can be deduced that, with the increase of reactor height-to-diameter ratio, a large bottom gap height is more conducive to oxygen mass transfer.

Considering the effect of bottom gap height on reactor mixing and oxygen mass transfer coefficient, it is better to choose bottom gap height of 63mm.

③The height of the liquid level is the height from the bottom of the three-phase separator to the liquid level. Its selection has been paid less attention by researchers. It determines the total amount of the gas-liquid mixture above the draft tube and directly affects the level at the top of the reactor. The gas-liquid-solid separation effect will affect the water quality of the effluent and the loss of the carrier. In the air volume, when UG>0.20cm/s, the change of liquid level has no effect on the cycle time, that is, the circulation speed is not affected by the change of liquid level. When the liquid level height is 250mm, the specific mixing time decreases rapidly, mainly because at this liquid level, the gas and water can bypass the top of the draft tube and enter the isolation tube to flow into the downflow area, and circulate from the upflow area to the downflow area. The fluids in the zone meet and mix, resulting in a greatly reduced mixing time. When the liquid level height is 160mm, the reactor has the highest volume oxygen total mass transfer coefficient, and when the liquid level height is 250mm, the reactor has the lowest volume oxygen mass transfer coefficient. The smaller the liquid level, the larger the volumetric oxygen mass transfer coefficient; conversely, the larger the liquid level, the smaller the volumetric oxygen mass transfer coefficient.

Finally, it is determined that the optimal structural parameters of the reactor are that the aspect ratio is preferably 6-13, more preferably 10; the liquid level height is preferably 150-300mm, more preferably 250mm; the bottom gap height is more preferably 60-70mm; more preferably 63mm.

The researcher of the present invention finds, in the water quality parameter scope of experiment, after the hydraulic retention time is greater than 2 hours, the removal of COD is not affected by the influent flow substantially; Best for removal.

The structure of the three-phase biological fluidized bed reactor adopted in one embodiment of the present invention is shown in Figure 2, and the bed wall of the fluidized bed is made of plexiglass. The upper separation zone of the reactor is a three-phase separator, which can effectively separate the gas, liquid and solid, and prevent the loss of the carrier. The carrier is ground ceramsite or volcanic rock, with a particle size of 0.3-0.45mm. The total effective volume of the fluidized bed reactor is 27.8L. The total height of the reactor is 2986mm, wherein the height Hr of the reaction zone is 2000mm, the diameter D of the reactor is 150mm, the height of the upflow cylinder (inner cylinder) is 1979mm, the diameter Dr of the inner cylinder is 100mm, the height of the liquid level is 250mm, and the height of the bottom gap is 63mm.

The aerobic nitrifying and denitrifying bacteria used in the present invention can be obtained by conventional domestication methods, such as biological domestication and cultivation by sludge inoculation, collecting activated sludge in the sewage reaction tank of monosodium glutamate factory, and hanging by rapid sludge discharge and film hanging method. membrane.

The operating steps of the present invention to purify monosodium glutamate waste water are as follows (concrete process is referring to Fig. 2):

1. Sewage is metered from the water inlet tank 10 through the peristaltic pump 9, and enters the fluidized bed reactor from the inner cylinder at the bottom of the reactor. The speed of the peristaltic pump is 30-35r/min.

2. The air is supplied by the air compressor 3, and after being decompressed by the oxygen pressure reducing valve 4, the flow rate is controlled by the gas rotameter 5. In the aeration zone 11, the gas is cut into small bubbles through the microporous titanium plate and enters the bottom of the reactor. Cartridge 12 for oxygen supply.

3. When the compressed air enters the upflow zone (inner cylinder) of the reactor through the microporous titanium plate, due to the promotion of the rising gas and the entrainment and mixing of air in the water, the three phases of gas, liquid and solid in the inner cylinder The mixture becomes less dense and flows upward. When the mixed liquid reaches the top 13 of the draft tube, most of the gas overflows the liquid surface, and the solid and liquid phases containing very few tiny bubbles enter the downflow zone (outer cylinder) 14. At this time, due to the reduction of the gas content of the mixed liquid, As a result, its density is relatively increased, and it flows to the bottom of the reactor by its own gravity and enters the next cycle. In this way, the three-phase mixed liquid flows upward in the inner cylinder and downward in the outer cylinder, forming an internal circulation flow in the reactor. The difference in density between the inner and outer cylinders of the three-phase mixed liquid is the driving force for the circulating flow of the reactor. Because the carrier is in a fluidized state, the mixing between the wastewater and the microorganisms attached to the carrier is increased, and at the same time, the thickness of the biofilm on the surface of the carrier can be effectively controlled by means of the collision and friction between the carriers, and the mass transfer effect can be enhanced.

4. The sewage is reciprocated in the fluidized bed, and is continuously discharged from the outlet to the horizontal flow sedimentation tank 8 for further sedimentation and discharged from the water outlet 1.

The preferred embodiments and beneficial effects of the present invention will be described in detail below in conjunction with specific examples.

Example 1

The reactor and operation steps of the above-mentioned embodiment are adopted to carry out the simulated monosodium glutamate wastewater treatment.

First, the low-concentration simulated monosodium glutamate waste water configured in the laboratory is sent into the reactor by the peristaltic pump 9. The liquid level has not crossed the overflow weir to stop the water intake, the air compressor 3 is turned on, the reactor is aerated, and the air flow meter 5 is adjusted to The air flow rate is controlled at 0.3-0.4m ³ /h, and the activated sludge obtained from the SBR reaction tank of the sewage treatment plant of Lianhua MSG Co., Ltd. is added to the reactor. The concentration of mixed microorganisms in the system is about 1.0-1.5g/L. The influent water quality indicators are shown in Table 1. After 24 hours of stuffy exposure, continuous water inflow was started and the concentration of ammonia nitrogen and COD was gradually increased according to the effluent water quality, while COD/NH ₄ ⁺ -N was adjusted to meet the actual ratio of MSG wastewater. The hydraulic retention time changed from 2h to 4h with the increase of pollutant concentration in the influent, and remained unchanged thereafter. Table 1 and Table 2 show the influent water quality in the start-up stage and circulation stage.

Table 1 Influent water quality in start-up stage

After domestication and cultivation, the sludge content in the internal circulation three-phase fluidized bed increases and adapts to the high concentration ammonia nitrogen environment, and can treat the simulated wastewater with a concentration consistent with the actual monosodium glutamate wastewater and discharge it up to the standard.

Change the influent to the actual monosodium glutamate comprehensive wastewater. Since the actual concentration of monosodium glutamate wastewater is high, it is not conducive to microbial film formation at the start-up stage. Therefore, the comprehensive wastewater is diluted and the dilution factor is gradually reduced to make the reactor adapt to high-concentration monosodium glutamate wastewater. The specific water quality is shown in Table 3.

table 3

Comparative Example 1

A monosodium glutamate factory uses the SBR process to treat monosodium glutamate wastewater. The specific process is that the comprehensive wastewater (including concentrated wastewater, refined wastewater, crude wastewater and fermentation wastewater) first enters the adjustment pool A and mixes evenly. If the pH and C/N If it is too low, the high-concentration wastewater in the regulating tank B will enter the A tank, which will increase the C/N. When the pH is greater than 6, the C/N is about 10, the COD _Cr concentration is about 2000, and the water volume is suitable, the comprehensive wastewater enters the reaction tank. A complete cycle of the treatment plant is generally 12 hours, starting from the water intake, 2 hours Stand still, aerate for 8 hours, settle for 2 hours, and drain the water. Sometimes, the values of ammonia nitrogen and COD do not meet the national discharge standard after 8 hours of aeration, so the aeration will be delayed until the standard is reached. The effluent can be used as dilution water in the adjustment tank, or it can be discharged into the storage tank as a reserve. Specifically The process is shown in Figure 3. In order to obtain more powerful experimental data and realize the optimal operation control of the process, the method of adjusting the influent water volume and tracking and testing various water quality indicators is adopted to seek the optimal control operation conditions.

The adjusted influent water volumes are 140m ³ , 160m ³ , 200m ³ , and 240m ³ . In order to obtain stable operation results, each flow rate is tracked and tested for at least five days under the same conditions.

The operation cycle of the reaction tank is generally: 12 hours a cycle, the water is allowed to stand for 2 hours, the aeration is 8 hours, the precipitation is 2 hours, and the water is drained. The specific test results are shown in Table 4:

Table 4

Compared with the results in Table 4, the removal load of the fluidized bed reactor of the present invention is higher than that of the traditional SBR treatment technology, and the highest removal load is shown in Table 5.

table 5

Claims (6)

1. a method for treating monosodium glutamate waste water in a three-phase biological fluidized bed reactor, is characterized in that, the method may further comprise the steps: (1) Domestication steps of aerobic nitrification and denitrification bacteria: A. Send the monosodium glutamate waste water with 200 mg of COD _Cr and 20 mg of ammonia nitrogen into the three-phase biological fluidized bed reactor equipped with a carrier by a peristaltic pump, and the liquid level is below the overflow weir to stop the water intake; B. Turn on the air compressor to aerate the reactor, the air flow rate is controlled at 0.3 ~ 0.4m ³ /h; the activated sludge obtained from the reaction tank of the monosodium glutamate sewage treatment plant is added to the reactor, and the concentration of mixed microorganisms in the system is 1.0 ~ 1.5g/L; add buffer to adjust the pH value of the water to 7 ~ 8, the temperature is 20 ~ 30 ℃, and the exposure is 24 ~ 48h; C. Afterwards, all the floating mud is discharged, and the reactor starts to continuously feed MSG wastewater, and the hydraulic retention time of the feed water is 2 hours; the first 1 to 15 days, the concentration of the feed water is controlled at 200 mg of COD _Cr , and 20 mg of ammonia nitrogen, and then 60 -90 days, the influent concentration gradually increased to 1600mg of COD _Cr and 160mg of ammonia nitrogen; (2) The domesticated aerobic nitrification and denitrification bacteria are fixed on the carrier of the three-phase biological fluidized bed, and the concentration of bacteria in the reactor is 6.0～8.0g/L; the outer surface of the three-phase biological fluidized bed reactor The ratio of barrel height to diameter is 6-13, and the bottom gap height is 60-70mm; (3) Adjust the concentration of monosodium glutamate production wastewater so that COD _Cr is lower than 1600 mg and ammonia nitrogen is lower than 160 mg; the monosodium glutamate production wastewater is sent into the three-phase biological fluidized bed reactor by the peristaltic pump, and the three-phase biological fluidized bed reactor The height of the liquid level from the bottom of the three-phase separator is 150-300mm, the hydraulic retention time of the incoming water is 2-7 hours, the air compressor is turned on to aerate the reactor, and the air flow rate is controlled at 0.3-0.4m ³ /h. 2. The method according to claim 1, wherein the ratio of the height to the diameter is 10, the liquid level is 250 mm, and the bottom gap is 63 mm. 3. The method according to claim 1, characterized in that, the total effective volume of the fluidized bed reactor is 25-30L; the total height of the reactor is 2800-3200mm; the height of the reaction zone is 1800-2200mm, and the reactor diameter 130-170mm, the height of the inner cylinder is 1800-2200mm, and the diameter of the inner cylinder is 80-120mm. 4. The method according to any one of claims 1-3, characterized in that the carrier accounts for 5%-8% of the effective volume of the reactor. 5. The method according to claim 4, characterized in that the particle size of the carrier is 0.3-0.45 mm. 6. The method according to claim 5, wherein the carrier is ground ceramsite or volcanic rock. the

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