Method and device for enhancing carbon source storage in activated sludge by non-steady-state carbon supply

Abstract

The present invention relates to the field of sewage biological treatment technology, and specifically to a method and device for enhancing carbon source storage in activated sludge through non-steady-state carbon supply. Specifically, the method comprises: inoculating activated sludge into a reactor, starting with domestic sewage and nitrate wastewater containing different COD concentrations as influent, pumping the activated sludge into the reactor via a peristaltic pump, and sequentially performing anaerobic stirring and anoxic stirring; the reactor operates for four cycles per day; the carbon source content in the activated sludge is regularly tested; a fluctuation of ±10% in the influent COD is the optimal non-steady-state carbon supply condition for the reactor, which can enable the carbon source content in the activated sludge of the reactor to reach a peak value. The present invention uses non-steady-state carbon supply control means to provide targeted stimulation to glycogen-accumulating bacteria to enhance their internal carbon source storage capacity, thereby achieving the purpose of improving the carbon source storage performance of the activated sludge without increasing the carbon source demand in the influent.

Description

Technical Field

[0001] The present invention relates to the technical field of biological sewage treatment, and in particular to a method and device for enhancing carbon source storage in activated sludge through non-steady-state carbon supply. Background Art

[0002] Anaerobic ammonium oxidation (ANAMMOX) technology converts ammonia nitrogen in wastewater into nitrogen gas under anaerobic conditions using nitrite as an electron acceptor. This process requires neither organic carbon nor oxygen, produces low sludge yields, and is an energy-efficient and cost-effective biological denitrification method. However, nitrite, a key substrate in the ANAMMOX reaction, is present in extremely low concentrations in natural water and wastewater, often requiring additional replenishment. This has become a major limitation to the widespread adoption of ANAMMOX technology in practical wastewater treatment.

[0003] In the biological denitrification process of sewage, short-cut denitrification is usually used to provide the required nitrite for anaerobic ammonium oxidation. Compared with traditional denitrification, short-cut denitrification is more efficient in producing nitrite and has lower energy consumption. Short-cut denitrification is an important way to obtain nitrite by selectively reducing nitrate to nitrite using organic matter as an electron donor under anaerobic or anoxic conditions. This process does not require oxygen and can save about 79% of the carbon source demand. This process also has certain limitations: (1) Due to the presence of exogenous carbon source, while driving short-cut denitrification, it also promotes the growth of common heterotrophic bacteria. These heterotrophic bacteria will compete with anaerobic ammonium oxidizing bacteria for nitrite substrates, affecting the growth and activity of anaerobic ammonium oxidizing bacteria; (2) When the external carbon source is sufficient, these heterotrophic bacteria may use the external carbon source to further denitrify nitrite, reducing the accumulation rate of nitrite.

[0004] To address the aforementioned issues with short-cut denitrification processes, the endogenous short-cut denitrification process has been developed in recent years. Using glycogen-accumulating and phosphate-accumulating bacteria as core microorganisms, it converts the external carbon source in wastewater into an internal carbon source for storage under anaerobic conditions. Under anoxic conditions, this stored internal carbon source is then used to perform short-cut denitrification of nitrate to produce stable nitrite. This process maximizes the utilization of the external carbon source in wastewater, prevents the overgrowth of common heterotrophic bacteria, provides more stable growth conditions for anaerobic ammonium-oxidizing bacteria, and achieves deep denitrification of wastewater.

[0005] This shows that the performance of endogenous short-range denitrification is largely determined by the carbon source storage capacity of glycogen-accumulating bacteria. Currently, some existing technologies have explored the effects of factors such as the type of influent carbon source, reaction time, pH, and competition with phosphate-accumulating bacteria on the internal carbon source storage capacity of glycogen-accumulating bacteria, but no reliable regulatory means have been developed to specifically enhance the internal carbon source storage capacity of glycogen-accumulating bacteria. Summary of the Invention

[0006] In response to the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a method and apparatus for enhancing the storage of carbon sources within activated sludge through non-steady-state carbon supply. The present invention adopts a non-steady-state carbon supply method to make the COD concentration of the influent of the sewage treatment system alternately fluctuate to a certain degree of high and low between adjacent cycle periods, thereby inhibiting the growth of common heterotrophic bacteria and stimulating the growth and activity of internal carbon source storage microorganisms. The present invention uses non-steady-state carbon supply regulation means to stimulate glycogen-accumulating bacteria in a targeted manner to enhance their internal carbon source storage capacity, thereby achieving the purpose of improving the endogenous short-range denitrification performance without increasing the influent carbon source demand.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A method for enhancing carbon source storage in activated sludge by non-steady-state carbon supply comprises the following steps:

[0009] Activated sludge was inoculated into the reactor to maintain the activated sludge concentration at 2500 mg / L~3500 mg / L. The reactor was operated for 4 cycles per day, each cycle was 6 hours, and each cycle included five stages: anaerobic stirring, anoxic stirring, sedimentation, drainage and idleness.

[0010] The reactor was started with the first and second domestic sewage with different COD concentrations and nitrate wastewater as influent. The first and second domestic sewage were alternately injected into the reactor within the initial 5-10 minutes of the anaerobic phase of adjacent cycles for anaerobic reaction, and the nitrate wastewater was injected into the reactor within the initial 5-10 minutes of the anoxic phase of each cycle for anoxic reaction. The anaerobic reaction and anoxic reaction were carried out sequentially in each cycle. Among them, the COD concentration of the first domestic sewage was higher than that of the second domestic sewage, and the non-steady-state carbon supply of the reactor showed high and low fluctuations between adjacent cycles. In the anaerobic phase, the glycogen-accumulating bacteria and phosphate-accumulating bacteria in the activated sludge converted the organic matter in the influent and stored it as endogenous carbon. At the same time, the phosphate-accumulating bacteria released phosphate. In the anoxic phase, the glycogen-accumulating bacteria used the endogenous carbon as an electron donor to carry out short-term denitrification of nitrate to produce nitrite, while consuming the internal carbon source. The phosphate-accumulating bacteria used nitrate or nitrite as an electron acceptor to absorb phosphorus.

[0011] During the operation of the reactor, the nutrient index of the effluent, the carbon source content in the activated sludge and the conversion rate of nitrate to nitrite were regularly tested. When the carbon source content in the activated sludge reached the peak value and the effluent COD concentration was lower than 50 mg / L, PO4 3- When the -P concentration is lower than 0.5 mg / L, it is the optimal condition for the non-steady-state carbon supply to enhance the carbon source storage in the activated sludge.

[0012] In a preferred embodiment of the present invention, the first domestic sewage and the second domestic sewage both contain COD, NH4+ -N and PO4 3- -P domestic sewage, wherein the COD concentration in the first domestic sewage is 400 mg / L~500 mg / L, the COD concentration in the second domestic sewage is 300 mg / L~400 mg / L, and the nitrate wastewater contains only NO3 - -N wastewater.

[0013] In a preferred embodiment of the present invention, the NH4 + -N and PO4 3- -P concentrations were 25 mg / L~35 mg / L and 2 mg / L~4 mg / L, respectively, and NO3 - -N concentration is 90 mg / L~110 mg / L.

[0014] In a preferred embodiment of the present invention, during the non-steady-state carbon supply period, the first domestic sewage and the second domestic sewage with different COD concentrations are alternately used as the influent of the anaerobic section of the reactor during adjacent circulation cycles.

[0015] In a preferred embodiment of the present invention, the COD concentrations in the first domestic sewage and the second domestic sewage fluctuate within a range of ±5% to ±20% between adjacent circulation cycles.

[0016] In a preferred embodiment of the present invention, the anaerobic stirring time is 90 min to 120 min, the anoxic stirring time is 30 min to 90 min, the sedimentation time is 30 min, the drainage time is 30 min, and the idle time is 120 min.

[0017] In a preferred embodiment of the present invention, the sludge age is controlled at 15 days, the pH is controlled at 7.0-8.0, and the drainage ratio is 50%-60%.

[0018] In a preferred embodiment of the present invention, the carbon source in the activated sludge is calculated as poly-β-hydroxy fatty acid esters, which are abbreviated as PHAs.

[0019] Another object of the present invention is to provide a device for enhancing carbon source storage in activated sludge through non-steady-state carbon supply, which is used to implement the above-mentioned method, including a reactor, a first domestic sewage inlet tank, a second domestic sewage inlet tank, a nitrate wastewater inlet tank and a peristaltic pump unit.

[0020] The first domestic sewage inlet tank, the second domestic sewage inlet tank and the nitrate wastewater inlet tank are respectively connected to the reactor through peristaltic pump units, and the reactor discharges the effluent after the reaction through the peristaltic pump units.

[0021] The COD concentrations of the first domestic sewage and the second domestic sewage in the first domestic sewage inlet tank and the second domestic sewage inlet tank fluctuate between adjacent circulation periods.

[0022] In a preferred embodiment of the present invention, the COD concentration in the first domestic sewage inlet tank is 400 mg / L~500 mg / L, and the COD concentration in the second domestic sewage inlet tank is 300 mg / L~400 mg / L.

[0023] In a preferred embodiment of the present invention, the peristaltic pump unit includes a first peristaltic pump, a second peristaltic pump, a third peristaltic pump, and a fourth peristaltic pump. The first domestic sewage inlet tank is connected to the reactor through the first peristaltic pump, the second domestic sewage inlet tank is connected to the reactor through the second peristaltic pump, and the nitrate wastewater inlet tank is connected to the reactor through the third peristaltic pump. The reactor discharges the effluent after the reaction through the fourth peristaltic pump, and an agitator is provided in the reactor.

[0024] The first domestic sewage inlet tank and the second domestic sewage inlet tank are both filled with domestic sewage, and the NH4 + -N and PO4 3- -P concentrations were 25 mg / L~35 mg / L and 2 mg / L~4 mg / L, respectively, and NO3 - -N concentration is 90mg / L~110 mg / L, and its COD, NH4 + -N and PO4 3- -P concentration is negligible.

[0025] Studies have shown that when microorganisms can obtain carbon sources stably, the internal carbon source storage response is often small. When they are unable to obtain external carbon sources at a fixed rate in a non-equilibrium growth environment, their internal carbon source storage capacity will be positively stimulated and gain a competitive advantage. Therefore, the present invention adopts a non-steady-state carbon supply method to make the COD content of the sewage treatment system influent fluctuate to a certain extent between adjacent cycles, thereby inhibiting the growth of common heterotrophic bacteria and stimulating the growth and activity of internal carbon source storage microorganisms.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention uses a method for strengthening the storage of carbon sources in activated sludge through non-steady-state carbon supply. The method starts with two types of domestic sewage and nitrate wastewater with different COD concentrations as influent. The domestic sewage and nitrate wastewater with different COD concentrations are respectively pumped into the reactor through different peristaltic pumps, and anaerobic stirring and anoxic stirring are performed in sequence. The COD content of the influent in the anaerobic section fluctuates between high and low cycles. In the anaerobic section, the glycogen-accumulating bacteria and phosphate-accumulating bacteria in the activated sludge convert and store organic matter in the influent as endogenous carbon. At the same time, the phosphate-accumulating bacteria release phosphate. In the anoxic section, the glycogen-accumulating bacteria use the endogenous carbon as an electron donor to perform short-term denitrification of nitrate to produce nitrite. The phosphate-accumulating bacteria use nitrate or nitrite as an electron acceptor to absorb phosphorus while consuming the internal carbon source. The non-steady-state carbon supply strategy is used to strengthen the internal carbon source storage capacity of the activated sludge, so as to improve the endogenous short-term denitrification performance without increasing the carbon source demand for the influent.

[0028] 2. The present invention adopts a non-steady-state carbon supply method, so that the COD content of the anaerobic influent of the sewage treatment system alternates between high and low fluctuations to a certain extent between adjacent cycles, creating an unbalanced growth environment for the microorganisms in the activated sludge, thereby inhibiting the growth of ordinary heterotrophic bacteria and stimulating the growth and activity of microorganisms that store internal carbon sources. When in this environment, microorganisms with the ability to store internal carbon sources, such as glycogen-accumulating bacteria, will gain a significant competitive advantage, and their internal carbon source storage capacity will be enhanced.

[0029] 3. The present invention effectively inhibits the growth of common heterotrophic bacteria in the endogenous short-range denitrification system through non-steady-state carbon supply. When coupled with the anaerobic ammonium oxidation system, it can reduce the negative impact of common heterotrophic bacteria on the growth of anaerobic ammonium oxidizing bacteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a device for enhancing the storage of carbon sources in activated sludge through non-steady-state carbon supply, 1-reactor, 2-first domestic sewage inlet tank, 3-second domestic sewage inlet tank, 4-nitrate wastewater inlet tank, 5-first peristaltic pump, 6-second peristaltic pump, 7-third peristaltic pump, 8-fourth peristaltic pump, 9-agitator. DETAILED DESCRIPTION

[0031] The following is a detailed description of the technical solutions in the embodiments of the present invention, using preferred embodiments and accompanying drawings in conjunction with the embodiments of the present invention. Obviously, the embodiments described 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 making creative efforts are within the scope of protection of the present invention.

[0032] It should be noted that all professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods.

[0033] Example 1

[0034] A device for enhancing carbon source storage in activated sludge through non-steady-state carbon supply includes a reactor 1, a first domestic sewage inlet tank 2, a second domestic sewage inlet tank 3, a nitrate wastewater inlet tank 4, a first peristaltic pump 5, a second peristaltic pump 6, a third peristaltic pump 7, a fourth peristaltic pump 8 and an agitator 9; the first domestic sewage inlet tank 2 and the second domestic sewage inlet tank 3 are connected to the reactor 1 through the first peristaltic pump 5 and the second peristaltic pump 6 respectively, and the nitrate wastewater inlet tank 4 is connected to the reactor 1 through the third peristaltic pump 7; an agitator 9 is provided in the reactor 1, and the reactor 1 discharges the effluent after the reaction through the fourth peristaltic pump 8.

[0035] The specific startup and operation control modes of the method of using non-steady-state carbon supply to stimulate the carbon source storage response in activated sludge are as follows:

[0036] The sludge was inoculated into the reactor 1 and the sludge concentration was maintained at 3000 mg / L.

[0037] The first domestic sewage and the second domestic sewage with COD concentrations of 420 mg / L and 380 mg / L are added to the first domestic sewage inlet tank 2 and the second domestic sewage inlet tank 3 respectively, wherein the NH4 + -N and PO4 3- The concentration of -P is 30 mg / L and 3 mg / L, and nitrate wastewater is added to the nitrate wastewater inlet tank 4. The NO3 in the nitrate wastewater - The system was started with the aforementioned domestic sewage and nitrate wastewater as influent, with the first and second domestic sewage pumped into reactor 1 via the first and second peristaltic pumps 5 and 6, respectively, within the initial 8 minutes of the anaerobic phase of each cycle. Nitrate wastewater was pumped into reactor 1 via the third peristaltic pump 7 within the initial 8 minutes of the anoxic phase of each cycle for anoxic reaction. The anaerobic and anoxic reactions proceeded sequentially. During the anaerobic phase, glycogen-accumulating bacteria and phosphate-accumulating bacteria utilized organic matter in the influent to store an internal carbon source. During the anoxic phase, glycogen-accumulating bacteria used the internal carbon source as an electron donor to perform short-range denitrification of nitrate to produce nitrite.

[0038] Reactor 1 operated for four 6-hour cycles per day, consisting of 120 minutes of anaerobic agitation, including 8 minutes of water inflow and 60 minutes of anoxic agitation. The remaining 60 minutes consisted of 8 minutes of water inflow, 30 minutes of sedimentation, 30 minutes of drainage, and 120 minutes of idle time. During the non-steady-state carbon supply period, the first domestic sewage with a COD concentration of 420 mg / L and the second domestic sewage with a COD concentration of 380 mg / L alternated between cycles as the influent to the anaerobic section of Reactor 1. This maintained the COD of the first and second domestic sewage influents within ±5% of each other. Sludge was discharged daily to maintain a sludge age of approximately 15 days, a pH of 7.2, and a drainage ratio of 57%.

[0039] Reactor 1 was operated under the above conditions, and the nutrient indicators of the effluent, the content of poly-β-hydroxy fatty acid esters in the activated sludge, and the conversion rate of nitrate to nitrite were regularly tested to evaluate the internal carbon source storage enhancement effect of reactor 1 under the non-steady-state carbon supply conditions of this range. The conversion rate of nitrate to nitrite is referred to as NTR.

[0040] Example 2

[0041] A device for enhancing the carbon source storage response in activated sludge through non-steady-state carbon supply includes a reactor 1, a first domestic sewage inlet tank 2, a second domestic sewage inlet tank 3, a nitrate wastewater inlet tank 4, a first peristaltic pump 5, a second peristaltic pump 6, a third peristaltic pump 7, a fourth peristaltic pump 8 and an agitator 9; the first domestic sewage inlet tank 2 and the second domestic sewage inlet tank 3 are connected to the reactor 1 through the first peristaltic pump 5 and the second peristaltic pump 6 respectively, and the nitrate wastewater inlet tank 4 is connected to the reactor 1 through the third peristaltic pump 7; an agitator 9 is provided in the reactor 1, and the reactor 1 discharges the effluent after the reaction through the fourth peristaltic pump.

[0042] The specific startup and operation control modes of the method of using non-steady-state carbon supply to stimulate the carbon source storage response in activated sludge are as follows:

[0043] The sludge was inoculated into the reactor 1 and the sludge concentration was maintained at 3000 mg / L.

[0044] The first domestic sewage and the second domestic sewage with COD concentrations of 440 mg / L and 360 mg / L are added to the first domestic sewage inlet tank 2 and the second domestic sewage inlet tank 3 respectively, wherein the NH4 + -N and PO4 3- The concentration of -P is 30 mg / L and 3 mg / L, and nitrate wastewater is added to the nitrate wastewater inlet tank 4. The NO3 in the nitrate wastewater -The system was initiated with the aforementioned domestic sewage and nitrate wastewater as influents, pumping the first and second domestic sewage into reactor 1 via the first and second peristaltic pumps 5 and 6, respectively, within the initial 8 minutes of the anaerobic phase of each cycle for anaerobic reaction. Nitrate wastewater was pumped into reactor 1 via the third peristaltic pump 7 within the initial 8 minutes of the anoxic phase of each cycle for anoxic reaction. The anaerobic and anoxic reactions proceeded sequentially. During the anaerobic phase, glycogen-accumulating bacteria and phosphate-accumulating bacteria utilized organic matter in the influent to store an internal carbon source. During the anoxic phase, glycogen-accumulating bacteria used the internal carbon source as an electron donor to perform short-range denitrification of nitrate to produce nitrite.

[0045] Reactor 1 operated for four 6-hour cycles per day, consisting of 120 minutes of anaerobic agitation, including 8 minutes of water inflow and 60 minutes of anoxic agitation. The remaining 60 minutes consisted of 8 minutes of water inflow, 30 minutes of sedimentation, 30 minutes of drainage, and 120 minutes of idle time. During the non-steady-state carbon supply period, the first domestic sewage with a COD concentration of 440 mg / L and the second domestic sewage with a COD concentration of 360 mg / L alternated as the influent to the anaerobic section of Reactor 1 between successive cycles. The COD of the first and second domestic sewage influents fluctuated within ±10%. Sludge was discharged daily to maintain a sludge age of approximately 15 days, a pH of 7.2, and a drainage ratio of 57%.

[0046] Reactor 1 was operated under the above conditions, and the poly-β-hydroxy fatty acid ester content in the activated sludge and the conversion rate of nitrate to nitrite were regularly tested to evaluate the internal carbon source storage enhancement effect of the reactor under the non-steady-state carbon supply conditions of this range.

[0047] Example 3

[0048] A device for enhancing carbon source storage in activated sludge through non-steady-state carbon supply includes a reactor 1, a first domestic sewage inlet tank 2, a second domestic sewage inlet tank 3, a nitrate wastewater inlet tank 4, a first peristaltic pump 5, a second peristaltic pump 6, a third peristaltic pump 7, a fourth peristaltic pump 8 and an agitator 9; the first domestic sewage inlet tank 2 and the second domestic sewage inlet tank 3 are connected to the reactor 1 through the first peristaltic pump 5 and the second peristaltic pump 6 respectively, and the nitrate wastewater inlet tank 4 is connected to the reactor 1 through the third peristaltic pump 7; the reactor 1 contains an agitator 9, and the reactor 1 discharges the effluent after the reaction through the fourth peristaltic pump 8.

[0049] The specific startup and operation control modes of the method of using non-steady-state carbon supply to stimulate the carbon source storage response in activated sludge are as follows:

[0050] The sludge was inoculated into the reactor 1 and the sludge concentration was maintained at about 3000 mg / L.

[0051] The first domestic sewage and the second domestic sewage with COD concentrations of 460 mg / L and 340 mg / L are added to the first domestic sewage inlet tank 2 and the second domestic sewage inlet tank 3 respectively, wherein the NH4 + -N and PO4 3- The concentration of -P is 30 mg / L and 3 mg / L, and nitrate wastewater is added to the nitrate wastewater inlet tank 4. The NO3 in the nitrate wastewater - The system was started with the aforementioned domestic sewage and nitrate wastewater as influent, with a -N concentration of 100.5 mg / L. The first and second domestic sewage were pumped into reactor 1 via the first and second peristaltic pumps 5 and 6, respectively, within the initial 8 minutes of the anaerobic phase of each adjacent cycle for anaerobic reaction. The nitrate wastewater was pumped into reactor 1 via the third peristaltic pump 7 within the initial 8 minutes of the anoxic phase of each cycle for anoxic reaction. The anaerobic and anoxic reactions proceeded sequentially. In the anaerobic phase, glycogen-accumulating bacteria and phosphate-accumulating bacteria utilized organic matter in the influent to store an internal carbon source. In the anoxic phase, glycogen-accumulating bacteria used the internal carbon source as an electron donor to perform short-range denitrification of nitrate to produce nitrite.

[0052] Reactor 1 operated for four 6-hour cycles per day, consisting of 120 minutes of anaerobic agitation, including 8 minutes of water inflow and 60 minutes of anoxic agitation. The remaining 60 minutes consisted of 8 minutes of water inflow, 30 minutes of sedimentation, 30 minutes of drainage, and 120 minutes of idle time. During the non-steady-state carbon supply period, the first domestic sewage with a COD concentration of 460 mg / L and the second domestic sewage with a COD concentration of 340 mg / L alternated as the influent to the anaerobic section of Reactor 1 between successive cycles. The influent C / N ratio fluctuated within ±15%. Sludge was discharged daily to maintain a sludge age of approximately 15 days, a pH of 7.2, and a drainage ratio of 57%.

[0053] Reactor 1 was operated under the above conditions, and the nutrient indicators of the effluent, the content of poly-β-hydroxy fatty acid esters in the activated sludge, and the conversion rate of nitrate to nitrite were regularly tested to evaluate the internal carbon source storage enhancement effect of the reactor under the non-steady-state carbon supply conditions of this range.

[0054] Example 4

[0055] A device for enhancing the carbon source storage response in activated sludge through non-steady-state carbon supply includes a reactor 1, a first domestic sewage inlet tank 2, a second domestic sewage inlet tank 3, a nitrate wastewater inlet tank 4, a first peristaltic pump 5, a second peristaltic pump 6, a third peristaltic pump 7, a fourth peristaltic pump 8 and an agitator 9; the first domestic sewage inlet tank 2 and the second domestic sewage inlet tank 3 are connected to the reactor 1 through the first peristaltic pump 5 and the second peristaltic pump 6 respectively, and the nitrate wastewater inlet tank 4 is connected to the reactor 1 through the third peristaltic pump 7; an agitator 9 is provided in the reactor 1, and the reactor 1 discharges the effluent after the reaction through the fourth peristaltic pump.

[0056] The specific startup and operation control modes of the method of using non-steady-state carbon supply to stimulate the carbon source storage response in activated sludge are as follows:

[0057] The sludge was inoculated into the reactor 1 and the sludge concentration was maintained at 2500 mg / L.

[0058] The first domestic sewage and the second domestic sewage with COD concentrations of 480 mg / L and 320 mg / L are added to the first domestic sewage inlet tank 2 and the second domestic sewage inlet tank 3 respectively, wherein the NH4 + -N and PO4 3- The concentration of -P is 25 mg / L and 2 mg / L, and nitrate wastewater is added to the nitrate wastewater inlet tank 4. The NO3 in the nitrate wastewater - The system was started with the aforementioned domestic sewage and nitrate wastewater as influent, with a -N concentration of 90 mg / L. The first and second domestic sewage were pumped into reactor 1 via first and second peristaltic pumps 5 and 6, respectively, within the initial 5 minutes of the anaerobic phase of each adjacent cycle for anaerobic reaction. The nitrate wastewater was pumped into reactor 1 via third peristaltic pump 7 within the initial 5 minutes of the anoxic phase of each cycle for anoxic reaction. The anaerobic and anoxic reactions proceeded sequentially. In the anaerobic phase, glycogen-accumulating bacteria and phosphate-accumulating bacteria utilized organic matter in the influent to store an internal carbon source. In the anoxic phase, glycogen-accumulating bacteria used the internal carbon source as an electron donor to perform short-range denitrification of nitrate to produce nitrite.

[0059] Reactor 1 operated for four 6-hour cycles per day, consisting of 90 minutes of anaerobic agitation, including 5 minutes of water inflow and 90 minutes of anoxic agitation. Within each 90 minutes, the anaerobic section of Reactor 1 was infused with 5 minutes of water, 30 minutes of sedimentation, 30 minutes of drainage, and 120 minutes of idle time. During the non-steady-state carbon supply period, domestic sewage with a COD concentration of 480 mg / L and 320 mg / L alternated between cycles as the influent to the anaerobic section of Reactor 1. The COD of the first and second influents fluctuated within ± 20%. Sludge was discharged daily to maintain a sludge age of approximately 15 days, a pH of 7.0, and a drainage ratio of 50%.

[0060] Reactor 1 was operated under the above conditions, and the nutrient indicators of the effluent, the content of poly-β-hydroxy fatty acid esters in the activated sludge, and the conversion rate of nitrate to nitrite were regularly tested to evaluate the internal carbon source storage enhancement effect of Reactor 1 under the non-steady-state carbon supply conditions of this range.

[0061] Example 5

[0062] A device for enhancing the carbon source storage response in activated sludge through non-steady-state carbon supply includes a reactor 1, a first domestic sewage inlet tank 2, a second domestic sewage inlet tank 3, a nitrate wastewater inlet tank 4, a first peristaltic pump 5, a second peristaltic pump 6, a third peristaltic pump 7, a fourth peristaltic pump 8 and an agitator 9; the first domestic sewage inlet tank 2 and the second domestic sewage inlet tank 3 are connected to the reactor 1 through the first peristaltic pump 5 and the second peristaltic pump 6 respectively, and the nitrate wastewater inlet tank 4 is connected to the reactor 1 through the third peristaltic pump 7; an agitator 9 is provided in the reactor 1, and the reactor 1 discharges the effluent after the reaction through the fourth peristaltic pump.

[0063] The specific startup and operation control modes of the method of using non-steady-state carbon supply to stimulate the carbon source storage response in activated sludge are as follows:

[0064] The sludge was inoculated into the reactor and the sludge concentration was maintained at 3500 mg / L.

[0065] The first domestic sewage and the second domestic sewage with COD concentrations of 440 mg / L and 360 mg / L are added to the first domestic sewage inlet tank 2 and the second domestic sewage inlet tank 3 respectively, wherein the NH4 + -N and PO4 3- The concentration of -P is 35 mg / L and 4 mg / L. Nitrate wastewater is added to the nitrate wastewater inlet tank 4. The NO3 in the nitrate wastewater -The system was initiated with domestic sewage and nitrate wastewater as the influents, with a -N concentration of 110 mg / L. The first and second domestic sewage were pumped into reactor 1 via the first and second peristaltic pumps 5 and 6, respectively, within the initial 10 minutes of the anaerobic phase of each cycle for anaerobic reaction. The nitrate wastewater was pumped into reactor 1 via the third peristaltic pump 7 within the initial 10 minutes of the anoxic phase of each cycle for anoxic reaction. The anaerobic and anoxic reactions proceeded sequentially. In the anaerobic phase, glycogen-accumulating bacteria and phosphate-accumulating bacteria utilized organic matter in the influent to store an internal carbon source. In the anoxic phase, glycogen-accumulating bacteria used the internal carbon source as an electron donor to perform short-range denitrification of nitrate to produce nitrite.

[0066] Reactor 1 operated for four 6-hour cycles per day, consisting of 150 minutes of anaerobic agitation, including 10 minutes of water inflow and 30 minutes of anoxic agitation. The remaining 30 minutes consisted of 10 minutes of water inflow, 30 minutes of sedimentation, 30 minutes of drainage, and 120 minutes of idle time. During the non-steady-state carbon supply period, domestic sewage with a COD concentration of 440 mg / L and domestic sewage with a COD concentration of 360 mg / L alternated as the influent to the anaerobic section of Reactor 1 between successive cycles. The COD of the first and second influents fluctuated within ±10%. Sludge was discharged daily to maintain a sludge age of approximately 15 days, a pH of 8.0, and a drainage ratio of 60%.

[0067] Reactor 1 was operated under the above conditions, and the poly-β-hydroxy fatty acid ester content in the activated sludge and the conversion rate of nitrate to nitrite were regularly tested to evaluate the internal carbon source storage enhancement effect of reactor 1 under the non-steady-state carbon supply conditions of this range.

[0068] The methods of Examples 4 and 5 are the same as those of Examples 1 to 3, except that, when experimental conditions permit, the amounts of certain raw materials and reaction conditions are changed. The methods of Examples 4 and 5 can also achieve the internal carbon source storage enhancement effect under non-steady-state carbon supply conditions.

[0069] Result Analysis

[0070] The strengthening effects of Examples 1 to 3 were analyzed, and the results showed that:

[0071] (1) Under the condition that the influent COD concentration remained stable, in the anaerobic stage, the influent COD was stored as an internal carbon source, and the PHAs content in the activated sludge at the end of the anaerobic stage was 132.0 mg COD / g Vss.

[0072] (2) During the non-steady-state carbon supply period, under the condition of influent COD fluctuation of ± 5%, the accumulation of PHAs in the activated sludge at the end of anaerobic period increased by 89.9 mg COD / g Vss compared with the stable stage, reaching 221.9 mg COD / g Vss. Under the condition of influent COD fluctuation of ± 10%, the accumulation of PHAs in the activated sludge at the end of anaerobic period in the reactor further increased to 401.6 mg COD / g Vss. Under the condition of influent COD fluctuation of ± 15%, the accumulation of PHAs in the activated sludge at the end of anaerobic period in the reactor decreased compared with the condition of influent COD fluctuation of ± 10%, reaching 303.4 mg COD / g Vss. It can be seen that the influent COD fluctuation of ± 10% is the optimal non-steady-state carbon supply control strategy for the reactor.

[0073] (3) When the COD fluctuation range of the influent is ± 10%, the NO3 - -N concentration decreased continuously from 24.0 mg / L to 0 at 60 min; NO2 - -N continued to accumulate, with the concentration rising from 0 to 16.2 mg / L, and NTR reaching 54.3%; at the same time, PO4 3- -P concentration continued to decrease, and the effluent concentration was 0.35 mg P / L.

[0074] The above results show that the fluctuation of COD in the anaerobic influent of the reactor enhances the PHAs content of the activated sludge in the anaerobic section of the reactor and the NO2 - -N accumulation, so that the system's NTR continues to increase. Under the condition that the COD fluctuation range of the reactor's anaerobic influent is ±10%, the reactor's internal carbon source storage is the highest, and a higher NO2 - -N accumulation and ideal effluent PO4 3- -P concentration, indicating that under this influent condition and operating conditions, influent COD fluctuation can significantly promote the internal carbon source storage performance and endogenous short-range denitrification activity of the reactor.

[0075] It should be noted that when the present invention relates to numerical ranges, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes the preferred embodiments. Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they understand the basic inventive concepts. Therefore, the attached protection scope is intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0076] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the present invention and its equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for enhancing carbon source storage in activated sludge by non-steady-state carbon supply, characterized in that: The following steps are involved: The reactor was inoculated with activated sludge to maintain the activated sludge concentration at 2500 mg / L-3500 mg / L. The reactor was operated for four cycles per day, each cycle lasting 6 hours. Each cycle included five stages: anaerobic stirring, anoxic stirring, sedimentation, drainage, and idleness. The reactor was started with the first and second domestic sewage with different COD concentrations and nitrate wastewater as influent. The first and second domestic sewage were alternately injected into the reactor within the initial 5 to 10 minutes of the anaerobic period of adjacent cycles for anaerobic reaction. The nitrate wastewater was injected into the reactor within the initial 5 to 10 minutes of the anoxic period of each cycle for anoxic reaction. The anaerobic reaction and anoxic reaction were carried out sequentially in each cycle. The COD concentration of the first domestic sewage was higher than that of the second domestic sewage. The non-steady-state carbon supply of the reactor caused the COD concentration of the domestic sewage entering the reactor to fluctuate between adjacent cycles. During the operation of the reactor, the nutrient index of the effluent, the carbon source content in the activated sludge and the conversion rate of nitrate to nitrite were regularly tested. When the carbon source content in the activated sludge reached the peak value and the effluent COD concentration was lower than 50 mg / L, PO4 3- When the -P concentration is lower than 0.5 mg / L, it is the optimal non-steady-state carbon supply condition, which can enhance the carbon source storage in the activated sludge; The first domestic sewage and the second domestic sewage both contain COD, NH4 + -N and PO4 3- -P domestic sewage, wherein the COD concentration in the first domestic sewage is 400 mg / L~500 mg / L, the COD concentration in the second domestic sewage is 300 mg / L~400 mg / L, and the nitrate wastewater contains only NO3 - -N wastewater; NH4 in the first and second domestic sewage + -N and PO4 3- -P concentrations were 25 mg / L~35 mg / L and 2 mg / L~4 mg / L, respectively, and NO3 - -N concentration is 90 mg / L~110 mg / L.

2. The method for enhancing carbon source storage in activated sludge by non-steady-state carbon supply according to claim 1, characterized in that: The COD concentrations in the first and second domestic sewage fluctuated between ± 5% and ± 20% during adjacent circulation cycles.

3. The method for enhancing carbon source storage in activated sludge by non-steady-state carbon supply according to claim 1, characterized in that: The anaerobic stirring time is 90 min~150 min, and the anoxic stirring time is 30 min~90 min.

4. The method for enhancing carbon source storage in activated sludge by non-steady-state carbon supply according to claim 1, characterized in that: The sludge age is controlled at 15 days, the pH is controlled at 7.0~8.0, and the drainage ratio is 50%~60%.

5. The method for enhancing carbon source storage in activated sludge by non-steady-state carbon supply according to claim 1, characterized in that: The carbon source in activated sludge is calculated based on the mass of poly-β-hydroxy fatty acid esters.

6. A device for enhancing carbon source storage in activated sludge by non-steady-state carbon supply, characterized in that: Used to implement the method according to claim 1, comprising a reactor (1), a first domestic sewage inlet tank (2), a second domestic sewage inlet tank (3), a nitrate wastewater inlet tank (4) and a peristaltic pump unit; The first domestic sewage inlet tank (2), the second domestic sewage inlet tank (3) and the nitrate wastewater inlet tank (4) are respectively connected to the reactor (1) via peristaltic pump units, and the reactor (1) discharges the effluent after the reaction via the peristaltic pump units; In the first domestic sewage inlet tank (2) and the second domestic sewage inlet tank (3), the COD concentrations in the first domestic sewage and the second domestic sewage fluctuate between adjacent circulation periods.

7. The device for enhancing carbon source storage in activated sludge by non-steady-state carbon supply according to claim 6, characterized in that: The peristaltic pump unit comprises a first peristaltic pump (5), a second peristaltic pump (6), a third peristaltic pump (7), and a fourth peristaltic pump (8); the first domestic sewage inlet tank (2) is connected to the reactor (1) via the first peristaltic pump (5); the second domestic sewage inlet tank (3) is connected to the reactor (1) via the second peristaltic pump (6); the nitrate wastewater inlet tank (4) is connected to the reactor (1) via the third peristaltic pump (7); the reactor (1) discharges the effluent after the reaction via the fourth peristaltic pump (8); and a stirrer (9) is provided in the reactor (1).

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