Aeration process and wastewater treatment method

Abstract

The application discloses an aeration process and a sewage treatment method, and belongs to the technical field of environmental engineering. The aeration process comprises the following steps: for the state that the adjusting tank is continuously fed with water, adjusting the working condition of an aeration equipment so that the dissolved oxygen concentration of the adjusting tank is controlled within 0.2-0.3 mg / L, and simultaneously carrying out nitrification and denitrification in the adjusting tank; for the state that the adjusting tank is intermittently fed with water or not fed with water, controlling the aeration equipment to be operated in an alternating mode of a third frequency and a fourth frequency, and carrying out denitrification in the adjusting tank. The aeration process disclosed by the application can achieve the purposes of degrading organic pollutants and saving energy by flexibly adjusting the mode of a process fan and controlling the dissolved oxygen interval.

Description

Technical Field

[0001] This invention belongs to the field of environmental engineering, and in particular relates to an aeration process and a wastewater treatment method. Background Technology

[0002] Beer production is highly seasonal, with the second and third quarters being the traditional peak consumption seasons, while the first and fourth quarters are generally the off-season. Beer wastewater mainly comes from the malting workshop, saccharification workshop, fermentation workshop (fermentation tank washing and filtration washing wastewater), bottling workshop (bottle washing, sterilization wastewater and beer spilled from broken bottles), cooling water, finished product workshop washing water, and domestic water used by factory employees.

[0003] The quality and quantity of wastewater from beer production vary with the peak and off-peak seasons. Brewery wastewater mainly contains organic matter such as sugars and alcohols, with high organic matter concentrations and good biodegradability. Wastewater containing residues, such as saccharification liquor and fermentation broth, contains a large amount of suspended organic solids.

[0004] Currently, beer wastewater is discharged in a mixed manner. Wastewater from each workshop shares a common wastewater pipeline and is collected in the same equalization tank. After thorough mixing, it is treated by anaerobic and aerobic systems. The aerobic system uses a blower aeration process, and the energy consumption of the blowers accounts for more than 50% of the total energy consumption of the wastewater treatment plant.

[0005] With continuous economic development and increasingly stringent environmental protection requirements, my country has built more and more wastewater treatment plants, making their optimized operation particularly important. On the one hand, the normal operation of wastewater treatment plants requires optimization to save energy and reduce emissions; on the other hand, the discharge standards for wastewater treatment plants are becoming increasingly stringent, necessitating optimization to improve treatment capacity.

[0006] In the biochemical degradation and denitrification process of brewery wastewater treatment plants, besides dissolved oxygen, two other important analytical parameters cannot be ignored: ammonia nitrogen and nitrate nitrogen (nitrate nitrogen). These parameters play a crucial role in achieving high treatment efficiency and effectiveness with low energy consumption. These three parameters are interrelated, and the proper adjustment of their concentration relationships directly affects the wastewater treatment effect and the power consumption of the blowers.

[0007] A complete denitrification process includes nitrification and denitrification. During nitrification, a blower introduces sufficient air, increasing the dissolved oxygen concentration and maintaining it at an average level of approximately 2 mg / L. Under aerobic conditions, ammonia nitrogen is converted to nitrate nitrogen. At this point, the ammonia nitrogen concentration gradually decreases, while the nitrate nitrogen concentration increases accordingly. During denitrification, the blower stops operating, and under anoxic conditions, nitrate nitrogen is gradually reduced to nitrogen gas, successfully completing the denitrification process. Simultaneously, the ammonia nitrogen concentration in the wastewater gradually increases. Real-time monitoring of the concentrations of ammonia (NH4+), nitrate nitrogen (NO3-), and dissolved oxygen in the water during this reaction process allows for accurate process model construction.

[0008] Existing integrated wastewater treatment processes for beer production require a large amount of energy in aerobic systems, which can easily lead to problems such as nitrogen loss, low efficiency, and high energy consumption. Summary of the Invention

[0009] This invention provides a wastewater treatment system that can flexibly adjust the mode of the process blower and control the dissolved oxygen range to achieve the purpose of degrading organic pollutants and saving energy.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention discloses an aeration process, comprising:

[0012] For equalization tanks with continuous water inflow, the operating conditions of the aeration equipment are adjusted to control the dissolved oxygen concentration in the equalization tank at 0.2-0.3 mg / L, and nitrification and denitrification occur simultaneously in the equalization tank.

[0013] For equalization tanks with intermittent or no water intake, the aeration equipment is controlled to operate alternately at the third and fourth frequencies, and denitrification takes place in the equalization tank.

[0014] According to another embodiment of the present invention, when the equalization tank is in a state of continuous water intake, the COD value of the continuous water intake is ≥1000mg / L, and the aeration equipment operates under the condition of alternating between a first frequency and a second frequency.

[0015] According to another embodiment of the present invention, the duration of the first frequency is 150-200s, and the duration of the second frequency is 400-450s.

[0016] According to another embodiment of the present invention, when the equalization tank is in a state of continuous water intake, the COD value of the continuous water intake is 800mg / L-1000mg / L, and the aeration equipment operates at a fixed first frequency in an intermittent manner.

[0017] According to another embodiment of the present invention, the duration of the first frequency is 150-200s, and the rest time of the aeration device is 700-750s.

[0018] According to another embodiment of the present invention, the third frequency is 20-30Hz, and the fourth frequency is 0Hz.

[0019] According to another embodiment of the present invention, the duration of the third frequency is 150-200s, and the duration of the third frequency is 720-900s.

[0020] According to another embodiment of the present invention, for the regulating tank to be intermittently filled, the duration of the third frequency is 150-200s, and the duration of the third frequency is 720-900s.

[0021] According to another embodiment of the present invention, when the regulating tank is not filled with water, the duration of the third frequency is 150-200s, and the duration of the third frequency is 720-900s.

[0022] In a second aspect, the present invention provides a wastewater treatment method, including the aeration process as described in any one of the first aspects.

[0023] The beneficial effects of this invention compared to the prior art are:

[0024] 1. The aeration process disclosed in this invention flexibly adjusts the mode of the blower in the aeration process according to the production wastewater situation. On the one hand, by increasing the working frequency of the aeration equipment, the dissolved oxygen concentration is increased, thereby achieving the purpose of degrading organic pollutants. On the other hand, by controlling the dissolved oxygen concentration, nitrification and denitrification reactions are carried out simultaneously in the nitrification tank, thereby enabling the denitrification of inorganic nitrogen such as nitrate nitrogen under aeration / intermittent aeration conditions.

[0025] 2. The aeration process disclosed in this invention can reduce the energy consumption of the aerobic treatment process by controlling the dissolved oxygen concentration in the equalization tank at 0.2-0.3 mg / L and using a low-frequency switching mode.

[0026] 3. The different modes of the aeration process disclosed in this invention can be automatically switched according to online detection data, and the fan operation mode can also be adapted to the peak and off-peak seasons of beer production, thereby reducing energy consumption. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the motion mode of a wastewater treatment system provided in an embodiment of the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] like Figure 1 As shown, the present invention provides an aeration process, comprising:

[0031] For equalization tanks with continuous water inflow, the operating conditions of the aeration equipment are adjusted to control the dissolved oxygen concentration in the equalization tank at 0.2-0.3 mg / L, and nitrification and denitrification occur simultaneously in the equalization tank.

[0032] For equalization tanks with intermittent or no water intake, the aeration equipment is controlled to operate alternately at the third and fourth frequencies, and denitrification takes place in the equalization tank.

[0033] Based on different influent conditions in the equalization tank and the brewery's consumption season, the different states of the influent, such as influent volume, flow rate, and COD value, can be determined. When the equalization tank is continuously receiving influent, it can be preliminarily determined that the brewery is in its peak consumption season. At this time, the operating conditions of the aeration equipment should be adjusted to control the dissolved oxygen concentration in the equalization tank at 0.2-0.3 mg / L, thereby achieving the effect of reducing energy loss while carrying out nitrification and denitrification.

[0034] When the equalization tank receives water intermittently or not at all, it is preliminarily determined that the brewery is in its off-season. Since the wastewater entering at this time is generally for cooling, washing, and domestic use, using high-powered aeration equipment would undoubtedly result in significant energy waste. Therefore, the aeration equipment is controlled to operate alternately at the third and fourth frequencies, keeping the dissolved oxygen concentration in the equalization tank low and primarily promoting denitrification. At least one of the third and fourth frequencies should be relatively low; for example, a very low third frequency ensures less energy consumption for the aeration equipment, while the fourth frequency maintains the activity of aerobic microorganisms. Alternating between the third and fourth frequencies allows the aeration equipment to operate with lower energy consumption, reducing the system's overall energy consumption.

[0035] Specifically, for a continuously fed equalization tank with a COD value ≥1000 mg / L, to maintain a dissolved oxygen concentration of 0.2-0.3 mg / L while reducing energy consumption, the aeration equipment operates at alternating frequencies of a first and a second frequency. Similar to the approach used when the equalization tank is intermittently fed or not fed at all, this alternation of high and low frequencies prevents the aeration equipment from operating at a consistently high frequency, thus reducing the overall operating frequency of the aeration equipment. During the aeration process, when the detection system detects a low dissolved oxygen concentration in the equalization tank, the aeration equipment is configured to operate at the high first frequency. Once the predetermined dissolved oxygen concentration is reached, it switches to the low second frequency, maintaining the dissolved oxygen concentration while reducing energy consumption.

[0036] To precisely plan the aeration process and control the aeration rhythm, the duration of the first and second frequencies is clearly defined. Specifically, the duration of the first frequency is 150-200 seconds, and the duration of the second frequency is 400-450 seconds, in order to stably maintain a suitable dissolved oxygen level and ensure a stable microbial environment. Preferably, the duration of the first frequency is 180 seconds, and the duration of the second frequency is 420 seconds.

[0037] When the equalization tank is continuously fed water with a COD value of 800 mg / L-1000 mg / L, and given the presence of certain concentrations of pollutants such as COD and ammonia nitrogen, the aeration equipment operates intermittently at a fixed first frequency to maintain a dissolved oxygen concentration of 0.2-0.3 mg / L. Compared to the previous continuous water feeding scenario, this extended downtime of the aeration equipment significantly reduces energy consumption.

[0038] It should be noted that, for ease of adjustment and replacement of the aeration equipment, the first frequency in this embodiment is the same as the first frequency in the above embodiments, and these two frequencies represent the operating conditions used in the same wastewater treatment method. In another embodiment, these two first frequencies may be different. In this case, since the mass of organic matter such as COD is less in this embodiment, a smaller value of the first frequency is used to reduce energy consumption.

[0039] To precisely plan the aeration process and control the aeration rhythm, specific plans are made for the first frequency and the stationary time of the aeration equipment. Specifically, the first frequency operates for 150-200 seconds, and the stationary time of the aeration equipment is 700-750 seconds, in order to stably maintain a suitable dissolved oxygen level and ensure the stability of the microbial environment. Preferably, the first frequency operates for 180 seconds, and the second frequency operates for 720 seconds.

[0040] For equalization tanks that are intermittently influent or not influent at all, the aeration equipment is controlled to operate alternately at a third frequency and a fourth frequency. The third frequency is 20-30Hz, and the fourth frequency is 0Hz. In other words, it operates intermittently at a fixed third frequency. Preferably, the third frequency is 30Hz. In this case, the aeration process can control the aeration equipment to operate at the third frequency and provide a suitable air volume when aeration is needed, meeting the basic dissolved oxygen requirements of microorganisms in the equalization tank and preventing long-term sludge settling and accumulation on the aeration equipment. When the aeration equipment operates at the fourth frequency, i.e., when it stops working, no additional energy consumption is generated.

[0041] In this scenario, the influent to the wastewater treatment system is relatively small, requiring minimal aeration. Therefore, the duration of the third frequency is set at 150-200 seconds, primarily to prevent sludge from accumulating and weighing down the aeration equipment. Since the wastewater treatment system has a longer dormancy period, the duration of the fourth frequency is set at 720-900 seconds, providing ample maintenance time. Preferably, the duration of the third frequency is 180 seconds, and the duration of the fourth frequency is 800 seconds.

[0042] When the equalization tank is not filled with water, the system enters a complete dormant state. Therefore, only necessary maintenance is required on the aeration equipment. The duration of the third frequency is 150-200 seconds, and the duration of the fourth frequency is 720-900 seconds. Preferably, the duration of the third frequency is 180 seconds, and the duration of the fourth frequency is 900 seconds.

[0043] In a second aspect, the present invention provides a wastewater treatment method, including the aeration process as described in any one of the first aspects.

[0044] The wastewater treatment method provided by this invention, by employing the aeration process described in the above embodiments, can achieve the goals of degrading organic pollutants and saving energy by flexibly adjusting the mode of the process blower and controlling the dissolved oxygen range.

[0045] Example 1

[0046] like Figure 1 The diagram shown illustrates the operation modes of a wastewater treatment system. This embodiment addresses the energy-saving goals achieved by flexibly adjusting the process fan modes during peak and off-peak seasons of beer production.

[0047] When breweries are engaged in saccharification or saccharification-containing packaging processes, and the brewery is primarily focused on saccharification production with continuous water intake, the high concentration of COD (Chemical Oxygen Demand) organic matter in the influent necessitates a fixed continuous water intake mode over high-frequency switching to ensure effluent compliance. This mode is achieved by real-time monitoring of dissolved oxygen levels to maintain the target dissolved oxygen concentration between 0.2-0.3 mg / L. If the dissolved oxygen (DO) value remains below the preset range, the high-frequency blower will continue to operate. Once the target dissolved oxygen concentration is reached, the blower will switch to low-frequency operation or shut down. After the low-frequency / shutdown period ends, even if the sludge remains within the target dissolved oxygen range, the blower will be forced into a high-frequency state to maintain sludge suspension. In practice, the blower's high-frequency / start-stop time is greater than or equal to the set time.

[0048] During the off-season, wastewater treatment, which mainly involves continuous influent from packaging wastewater, operates in a start-stop mode. Since packaging wastewater still contains certain concentrations of pollutants such as COD and ammonia nitrogen, the target dissolved oxygen concentration is controlled at 0.2-0.3 mg / L. Continuous influent is used, and the duration of low-frequency / shutdown is appropriately extended.

[0049] During peak production season, when water production shifts from high output to a 7-day shutdown, the system switches from the first mode (high and low frequency) to the second mode (start and stop) to further extend the duration of blower shutdown. At the same time, an intermittent water intake mode is adopted to ensure the activity of aerobic system microorganisms and achieve the purpose of intermittent aeration.

[0050] During the off-season, especially when production is suspended, the second mode of timed start / stop operation of the fan is selected to achieve the lowest possible level of operation.

[0051] In the second mode, the blower operates strictly according to the set start and stop times. It remains running during the off-season when the system is in hibernation to prevent sludge from settling and accumulating on the aeration equipment. Blower operation is a necessary maintenance measure.

[0052] It should be noted that, due to the frequent switching required in this embodiment, the blower will be started and stopped a maximum of 6 times per hour. A screw blower is selected for the aeration process to adapt to the frequent start-stop conditions. TPU aeration hoses are selected for the aeration equipment, as they offer high oxygen mass transfer efficiency, are more energy-efficient, and facilitate precise oxygen control. In this embodiment, to monitor changes in nitrate nitrogen and ammonia nitrogen in the equalization tank in real time, online monitoring devices for ammonia nitrogen and nitrate nitrogen are also installed on the equalization tank. In wastewater treatment plants where total nitrogen in the effluent is assessed, a raw water bypass system is also required, working in conjunction with an online nitrate nitrogen probe. When the detected total nitrogen value in the effluent exceeds a preset value, the raw water bypass system will automatically activate to provide a carbon source for denitrification.

[0053] At 1500m 3In actual beer wastewater treatment projects, based on the seasonal changes in beer production, the energy consumption per ton of water in the aerobic process section of beer wastewater treatment can be reduced by more than 15-20% compared to traditional processes through the operation of the process and the application of fan mode switching measures. In particular, for projects with total nitrogen emission requirements, maintaining low dissolved oxygen operation in the first mode of the fan can save more than 20% of the reagent dosage.

[0054] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An aeration process, characterized in that, include: For a continuously fed equalization tank, the operating conditions of the aeration equipment are adjusted to control the dissolved oxygen concentration in the equalization tank at 0.2-0.3 mg / L, with nitrification and denitrification occurring simultaneously within the equalization tank. If the COD value of the continuously fed water is ≥1000 mg / L, the aeration equipment operates alternately at a first frequency for 150-200 s and a second frequency for 400-450 s. If the COD value of the continuously fed water is 800 mg / L-1000 mg / L, the aeration equipment operates intermittently at a fixed first frequency, with the first frequency lasting 150-200 s and the aeration equipment remaining stationary for 700-750 s. For the equalization tank, which is intermittently filled or not filled at all, the aeration equipment is controlled to operate alternately at the third and fourth frequencies, and denitrification takes place in the equalization tank; the third frequency is 20-30 Hz, and the fourth frequency is 0 Hz; the duration of the third frequency is 150-200 s, and the duration of the fourth frequency is 720-900 s.

2. A wastewater treatment method, characterized in that, Includes the aeration process as described in claim 1.

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