Aeration process and sewage treatment method

Abstract

The invention 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: when a regulating tank is in a continuous water inlet state, regulating the working condition of aeration equipment to control the dissolved oxygen concentration of the regulating tank to be 0.2-0.3 mg / L, and synchronously carrying out nitrification and denitrification in the regulating tank; and for intermittent water feeding or no water feeding of the regulating tank, controlling the aeration equipment to operate in a manner of alternating a third frequency and a fourth frequency, and carrying out denitrification in the regulating tank. According to the aeration process disclosed by the invention, the purposes of degrading organic pollutants and saving energy are achieved by flexibly adjusting the mode of the process fan and controlling the dissolved oxygen interval.

Description

Technical Field

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

[0002] Beer production has a very obvious seasonality. The second and third quarters are traditional peak seasons, while the first and fourth quarters are generally off-seasons. Beer wastewater mainly comes from the malt workshop, saccharification workshop, fermentation workshop (fermentation tank washing, filter washing wastewater), filling workshop (bottle washing, sterilization wastewater and beer flowing out of broken bottles), cooling water, finished product workshop washing water and factory employees' living water.

[0003] The quality and quantity of comprehensive wastewater from beer production change with the peak and off-peak seasons. Brewery wastewater mainly contains organic matter such as sugars and alcohols, with high concentrations and good biodegradability. Saccharification liquid, fermentation liquid and other residue-containing wastewater contain a large amount of organic suspended solids.

[0004] At present, brewery wastewater adopts mixed discharge mode. Wastewater produced by each workshop shares wastewater pipeline and is collected in the same regulating tank. After being fully mixed, it is treated by anaerobic and aerobic systems. The aerobic system adopts aeration technology, and the energy consumption of fans accounts for more than 50% of the total energy consumption of the sewage plant.

[0005] With the continuous development of economy and the gradual improvement of environmental protection requirements, more and more sewage treatment plants have been built in my country, and the optimized operation of sewage treatment plants is particularly important. On the one hand, the normal operation of sewage treatment plants needs to be optimized to save energy and reduce emissions; on the other hand, the emission standards of sewage treatment plants are becoming increasingly stringent, and optimization is needed to improve the treatment capacity.

[0006] In the process of biochemical degradation and denitrification in brewery wastewater treatment plants, in addition to dissolved oxygen, there are two important analytical parameters that cannot be ignored, namely ammonia nitrogen and nitrate nitrogen (nitric nitrogen). These parameters play a vital role in achieving high treatment efficiency and effect under low energy consumption conditions. These three parameters are interrelated, and the adjustment of the corresponding relationship between their concentrations is directly related to the effect of sewage treatment and the power consumption of the fan.

[0007] A complete denitrification process includes nitrification and denitrification. During the nitrification process, the fan introduces sufficient air, the dissolved oxygen concentration increases and is maintained at an average level of about 2 mg / l, and ammonia nitrogen is converted into nitrate nitrogen in an aerobic environment. At this time, the ammonia nitrogen concentration will gradually decrease, and the nitrate nitrogen concentration will increase accordingly. During the denitrification process, the fan stops working, and the nitrate nitrogen is gradually reduced to nitrogen gas in an anoxic environment. The nitrogen removal process is successfully completed, and the ammonia nitrogen concentration in the sewage gradually increases. During this reaction process, the concentrations of ammonia NH4+, nitrate nitrogen N03-, and dissolved oxygen in the water body are detected in real time, and an accurate process model can be constructed.

[0008] The existing comprehensive wastewater treatment process for beer production requires a lot of energy in an aerobic system, and is prone to problems such as nitrogen loss, low efficiency and high energy consumption. Summary of the invention

[0009] The present invention provides a sewage treatment system, which can flexibly adjust the mode of a process fan and control the dissolved oxygen range, so as to achieve the purpose of degrading organic pollutants and saving energy.

[0010] In order to achieve the above object, the present invention adopts the following technical scheme:

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

[0012] When the regulating pond is in a state of continuous water inflow, the working conditions of the aeration equipment are adjusted to control the dissolved oxygen concentration in the regulating pond at 0.2-0.3 mg / L, and nitrification and denitrification are carried out simultaneously in the regulating pond;

[0013] When the regulating pond is intermittently inflowed with water or not inflowed with water, the aeration equipment is controlled to operate in a third frequency and a fourth frequency alternately, and denitrification is carried out in the regulating pond.

[0014] According to another embodiment of the present invention, when the regulating pond is in a state of continuous water inflow, the COD value of the continuous water inflow is ≥1000 mg / L, and the working condition of the aeration equipment is to operate in a manner of alternating between the first frequency and the second frequency.

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

[0016] According to another embodiment of the present invention, when the regulating pond is in a state of continuous water inflow, the COD value of the continuous water inflow is 800 mg / L-1000 mg / L, and the working condition of the aeration equipment is to operate intermittently at a fixed first frequency.

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

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

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

[0020] According to another embodiment of the present invention, when the regulating tank is intermittently inflowing water, the action time of the third frequency is 150-200 s, and the action time of the third frequency is 720-900 s.

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

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

[0023] The beneficial effects of the present invention compared with the prior art are:

[0024] 1. The aeration process disclosed in the present invention flexibly adjusts the mode of the fan in the aeration process according to the production drainage conditions. On the one hand, the dissolved oxygen concentration is increased by increasing the working frequency of the aeration equipment to achieve 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 denitrifying inorganic nitrogen such as nitrate nitrogen under aeration / intermittent aeration conditions.

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

[0026] 3. The different modes of the aeration process disclosed in the present invention can be automatically switched according to online detection data, and the fan operation mode can be adaptively changed according to the off-season and peak-season of beer production, thereby reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0028] Figure 1 A schematic diagram of the movement mode of a sewage treatment system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work 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] When the regulating pond is in a state of continuous water inflow, the working conditions of the aeration equipment are adjusted to control the dissolved oxygen concentration in the regulating pond at 0.2-0.3 mg / L, and nitrification and denitrification are carried out simultaneously in the regulating pond;

[0032] When the regulating pond is intermittently inflowed with water or not inflowed with water, the aeration equipment is controlled to operate in a third frequency and a fourth frequency alternately, and denitrification is carried out in the regulating pond.

[0033] According to the different water inflow conditions of the regulating tank, combined with the consumption season of the brewery at that time, it is possible to judge the different states of the water inflow, such as water inflow, flow rate, COD value, etc. When the regulating tank is in a state of continuous water inflow, it can be preliminarily judged that the brewery is in the peak consumption season. At this time, the working conditions of the aeration equipment are adjusted and the dissolved oxygen concentration of the regulating tank is controlled at 0.2-0.3mg / L, so as to achieve the effect of reducing energy loss while nitrification and denitrification.

[0034] When the regulating tank is intermittently inflowing or not inflowing, it is preliminarily judged that the beer factory is in the off-season. Since the sewage inflow at this time is generally cooling, washing, domestic water, etc., using high-power aeration equipment for aeration will undoubtedly cause a lot of energy waste. At this time, the aeration equipment is controlled to operate in an alternating manner of the third frequency and the fourth frequency, so that the dissolved oxygen concentration in the regulating tank is low and mainly denitrification is carried out. At least one of the third and fourth frequencies is relatively small. For example, the third frequency is very small, so that the aeration equipment generates less energy consumption when operating at the third frequency, and can ensure the activity of aerobic system microorganisms when operating at the fourth frequency. The alternation of the third and fourth frequencies enables the aeration equipment to operate at lower energy consumption, reducing the energy consumption of the system.

[0035] Specifically, when the regulating tank is in a state of continuous water inflow, and the COD value of the continuous water inflow is ≥1000mg / L, in order to maintain the dissolved oxygen concentration in the regulating tank at 0.2-0.3mg / L while reducing the energy consumption of the regulating tank, the working condition of the aeration equipment is to operate in a manner alternating between the first frequency and the second frequency. Using a similar idea to the case where the regulating tank is intermittently inflowing or not inflowing water, a combination of a large frequency and a small frequency is used to avoid the aeration equipment from always operating under the condition of a high frequency, thereby reducing the overall working frequency of the aeration equipment. In the specific aeration process, when the detection system finds that the dissolved oxygen concentration in the regulating tank is low, the aeration equipment will be configured to operate under the condition of a high frequency of the first frequency. When the predetermined dissolved oxygen concentration is reached, the aeration equipment will be operated under the condition of a low frequency of the second frequency, thereby maintaining the dissolved oxygen concentration in the regulating tank while reducing the energy consumption of the aeration equipment.

[0036] In order to accurately plan the aeration process and accurately control the aeration rhythm, the action time of the first frequency and the second frequency is clearly planned. Specifically, the action time of the first frequency is 150-200s, and the action time of the second frequency is 400-450s, so as to stably maintain a suitable dissolved oxygen level and ensure the stability of the microbial environment. Preferably, the action time of the first frequency is 180s, and the action time of the second frequency is 420s.

[0037] When the regulating pool is in a state of continuous water inflow, the COD value of the continuous water inflow is 800mg / L-1000mg / L. Since there are still certain concentrations of pollutants such as COD and ammonia nitrogen in the regulating pool at this time, in order to maintain the dissolved oxygen concentration in the regulating pool at 0.2-0.3mg / L, the working condition of the aeration equipment is to operate intermittently at a fixed first frequency. Compared with the previous continuous water inflow situation, this situation prolongs the shutdown time of the aeration equipment and can significantly reduce energy consumption.

[0038] It should be noted that, in order to facilitate the adjustment and replacement of the aeration equipment, the first frequency of this embodiment and the first frequency of the above embodiment are the same and the two frequencies are the operating conditions adopted by the same sewage treatment method. In another embodiment, the two first frequencies can be different. At this time, since the mass of organic matter such as COD in this embodiment is less, in order to reduce energy consumption, the value of the first frequency adopted in this embodiment is smaller.

[0039] In order to accurately plan the aeration process and accurately control the aeration rhythm, the first frequency and the static time of the aeration equipment are clearly planned. Specifically, the action time of the first frequency is 150-200s, and the static time of the aeration equipment is 700-750s, so as to stably maintain the appropriate dissolved oxygen level and ensure the stability of the microbial environment. Preferably, the action time of the first frequency is 180s, and the action time of the second frequency is 720s.

[0040] For the equalization tank with intermittent water inflow or no water inflow, the aeration equipment is controlled to operate in an alternating manner of the third frequency and the fourth frequency, wherein the third frequency is 20-30Hz, and the fourth frequency is 0Hz. In other words, it is operated intermittently with a fixed third frequency. Preferably, the third frequency is 30Hz. In this case, when aeration is needed, the aeration process can control the aeration equipment to operate at the third frequency and provide an appropriate amount of gas to meet the basic dissolved oxygen demand of the microorganisms in the equalization tank and avoid long-term sedimentation and accumulation of sludge in the aeration equipment. The aeration equipment uses the fourth frequency, that is, the aeration equipment stops working and does not generate additional energy consumption.

[0041] In this case, the sewage treatment system has less influent sewage and does not require a large amount of aeration, so the action time of the third frequency is 150-200s, just to prevent the sludge from settling and piling up in the aeration equipment for a long time. The sewage treatment system is dormant for a long time, and the action time of the fourth frequency is 720-900s, giving the system sufficient maintenance time. Preferably, the action time of the third frequency is 180s, and the action time of the fourth frequency is 800s.

[0042] When the regulating tank is not filled with water, the system completely enters a dormant state. Therefore, only necessary maintenance is performed on the aeration equipment. The action time of the third frequency is 150-200s, and the action time of the fourth frequency is 720-900s. Preferably, the action time of the third frequency is 180s, and the action time of the fourth frequency is 900s.

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

[0044] The sewage treatment method provided by the present invention, since it adopts the aeration process described in the above embodiment, can achieve the purpose of degrading organic pollutants and saving energy by flexibly adjusting the mode of the process fan and controlling the dissolved oxygen range.

[0045] Example 1

[0046] like Figure 1 The figure shows a schematic diagram of the movement mode of the sewage treatment system. This embodiment aims at the off-season and peak-season of beer production, and achieves the purpose of energy saving by flexibly adjusting the mode of the process fan.

[0047] When the brewery is carrying out the process of saccharification or saccharification packaging at the same time, under the condition of continuous water inflow for brewery production mainly for saccharification production, because the inflow contains high concentration of COD organic matter, in order to ensure the compliance of the effluent index, it takes priority over the high-low frequency switching mode operation, fixes the continuous water inflow as the water inflow mode, and controls the target dissolved oxygen concentration at 0.2-0.3mg / L through real-time monitoring of the dissolved oxygen detector. If the DO (dissolved oxygen) dissolved oxygen value is still lower than the preset range, the high-frequency fan will be started continuously. When the target dissolved oxygen concentration is reached, the fan will enter low frequency or stop. After the low frequency / stop time ends, even if it is still in the target dissolved oxygen range, in order to maintain the suspension of the mud, the fan will enter the forced high frequency state. In fact, the high frequency / start-stop time of the fan ≥ the set time.

[0048] During the off-season, wastewater treatment, which mainly relies on continuous water inflow from packaging drainage, adopts a start-stop mode. Since packaging wastewater still contains a certain concentration of pollutants such as COD and ammonia nitrogen, the target dissolved oxygen concentration is controlled at 0.2-0.3 mg / L. Continuous water inflow is adopted to appropriately extend the low-frequency / shutdown time.

[0049] During the peak production season, when water production changes from high production to a 7-day shutdown condition, the high-low frequency switching from the first mode to the second mode start and stop is adopted to further extend the duration of the fan shutdown. At the same time, the intermittent water inlet mode is adopted to ensure the activity of the microorganisms in the aerobic system and achieve the purpose of intermittent aeration.

[0050] During the off-season, especially when production is stopped, select the second mode of scheduled fan start / stop to achieve the lowest level of operation.

[0051] In the second mode, the fan operates strictly according to the set start and stop times, and keeps running when the system is dormant during the off-season. This is to prevent sludge from settling and accumulating in the aeration equipment for a long time. Running the fan is a necessary maintenance measure.

[0052] It should be noted that due to the need for frequent switching in this embodiment, the fan will be started and stopped up to 6 times per hour. The fan in the aeration process selects a screw fan to adapt to the working conditions of frequent start and stop. The aeration equipment process selects TPU aeration hose. TPU aeration hose has high oxygen mass transfer efficiency, is more energy-efficient, and is easy to achieve precise oxygen control. In order to be able to detect the changes in nitrate nitrogen and ammonia nitrogen in the regulating tank in real time, this embodiment is also equipped with ammonia nitrogen and nitrate nitrogen online monitoring equipment on the regulating tank. In sewage stations where the total nitrogen in the effluent is assessed, it is also necessary to install a raw water override system, in conjunction with the nitrate nitrogen online probe. When the total nitrogen detection value of the effluent is higher than the preset value, the raw water override will be automatically opened to provide a carbon source for denitrification.

[0053] At 1500m 3 / d In the actual beer wastewater treatment project, according to the changes in the beer production season, through the operation of the process and the use of fan mode switching measures, the energy consumption per ton of water in the aerobic process section of beer wastewater treatment can be saved by more than 15-20% compared with the traditional process. Especially for those with assessment requirements for total nitrogen effluent, by maintaining low dissolved oxygen operation in the first mode, the dosage of reagents can be saved by more than 20%.

[0054] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. An aeration process, characterized in that: include: When the regulating pond is in a state of continuous water inflow, the working conditions of the aeration equipment are adjusted to control the dissolved oxygen concentration in the regulating pond at 0.2-0.3 mg / L, and nitrification and denitrification are carried out simultaneously in the regulating pond; When the regulating pond is intermittently inflowed with water or not inflowed with water, the aeration equipment is controlled to operate in a third frequency and a fourth frequency alternately, and denitrification is carried out in the regulating pond.

2. The aeration process according to claim 1, characterized in that: When the regulating pond is in a state of continuous water inflow, the COD value of the continuous water inflow is ≥1000 mg / L, and the working condition of the aeration equipment is to operate in a manner of alternating the first frequency and the second frequency.

3. The aeration process according to claim 2, characterized in that: The action time of the first frequency is 150-200s, and the action time of the second frequency is 400-450s.

4. The aeration process according to claim 1, characterized in that: When the regulating pond is in a state of continuous water inflow, the COD value of the continuous water inflow is 800 mg / L-1000 mg / L, and the working condition of the aeration equipment is to operate intermittently at a fixed first frequency.

5. The aeration process according to claim 4, characterized in that: The action time of the first frequency is 150-200s, and the static time of the aeration device is 700-750s.

6. The aeration process according to claim 1, characterized in that: The third frequency is 20-30 Hz, and the fourth frequency is 0 Hz.

7. The aeration process according to claim 6, characterized in that: The action time of the third frequency is 150-200s, and the action time of the third frequency is 720-900s.

8. The aeration process according to claim 1, characterized in that: For the intermittent water inflow into the regulating tank, the action time of the third frequency is 150-200s, and the action time of the fourth frequency is 720-900s.

9. The aeration process according to claim 1, characterized in that: When the regulating tank is not filled with water, the action time of the third frequency is 150-200s, and the action time of the fourth frequency is 720-900s.

10. A method for treating sewage, characterized in that: The invention comprises the aeration process as described in any one of claims 1 to 9.

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