Anaerobic granular sludge storage and start-up method

Abstract

The application discloses an anaerobic granular sludge storage and starting method, and relates to the technical field of environmental protection, which is used to solve the problems of long starting time and easy damage during storage and starting of the anaerobic granular sludge; the method comprises the following steps: placing the anaerobic granular sludge to be stored in an anaerobic reactor, emptying water after the anaerobic granular sludge is settled, adding a prepared nutrient solution, and adding the nutrient solution to a certain height above the anaerobic granular sludge; finally, the pressure above the anaerobic granular sludge is made to reach 20-25 m of water column, and the anaerobic reactor is sealed for storage under undisturbed anaerobic conditions; during starting, the wastewater to be treated and the nutrient solution are mixed at a certain proportion, and then added into the anaerobic reactor; the proportion of the wastewater in the mixed solution is gradually increased until 100%; after 5-15 days, when the COD removal rate reaches 80%, and the sludge concentration increases by 15-20%, the starting is successful; the anaerobic granular sludge can be stored for 1-2 years and still has activity and is not disintegrated, and the performance of the anaerobic granular sludge can be quickly recovered within 10-15 days.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of environmental protection, in particular to an anaerobic granular sludge storage and starting method. BACKGROUND

[0002] With the substantial increase in population and rapid economic development, the people's living standards in China are increasingly demanding, and various high-concentration sewage has also been generated. The traditional anaerobic sewage treatment process is mostly flocculent activated sludge, but the flocculent sludge has limited effect on high-concentration COD treatment. The emergence of anaerobic granular sludge greatly solves the problem of difficult treatment of high-concentration COD. Compared with the traditional anaerobic sludge, the anaerobic granular sludge not only has an organic matter treatment efficiency of about 30% higher, but also has a compact structure, excellent settling performance, large biomass, and can tolerate high organic load. Compared with the general anaerobic sludge, the anaerobic granular sludge technology has obvious advantages in treatment effect, cost, and process land occupation.

[0003] At present, although the anaerobic granular sludge has many advantages, there are many problems in the storage and starting of the anaerobic granular sludge. In the actual production of wastewater biological treatment, the anaerobic granular sludge has a slow cultivation speed, thereby causing the upflow anaerobic sludge bed (UASB), internal circulation (IC), and other anaerobic reactors to need a long time from starting to stable operation, which is short for two or three months and long for even half a year, seriously affecting the normal production of enterprises. Therefore, during the shutdown or intermittent operation of the enterprises, the anaerobic granular sludge needs to be stored to reduce the starting time. However, the anaerobic granular sludge is easy to disintegrate and inactivate during storage; and the anaerobic granular sludge is easy to hollow during improper starting, resulting in a large amount of granular sludge floating and losing activity. Therefore, an anaerobic granular sludge storage and starting method is urgently needed to solve this problem. SUMMARY

[0004] The present application aims to provide an anaerobic granular sludge storage and starting method to solve the problems of long starting time of the anaerobic granular sludge and easy damage during storage and starting.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solution: an anaerobic granular sludge storage method, comprising the following steps: placing the anaerobic granular sludge to be stored in an anaerobic reactor, emptying the water after the anaerobic granular sludge is settled, adding the prepared nutrient solution, and the nutrient solution addition amount is higher than a certain height of the anaerobic granular sludge; and finally making the pressure above the anaerobic granular sludge reach 20-25 m of water column, and sealing the anaerobic reactor for storage under undisturbed anaerobic conditions.

[0006] Preferably, in the nutrient solution: the COD concentration is 5000-8000 mg / L, the carbon source includes sodium acetate or carbon-containing production wastewater; ammonium chloride is used as the nitrogen source, NH 4+The concentration of N is 15-20 mg / L, the concentration of potassium dihydrogen phosphate as the phosphorus source is 1-3 mg / L, and the pH of the nutrient solution is 9-10.

[0007] Preferably, the feeding amount of the nutrient solution is 30-50 cm higher than the anaerobic granular sludge, and the method for making the pressure above the anaerobic granular sludge reach 20-25 m of water column is nitrogen charging and pressurizing; or the height of the anaerobic reactor is just enough to make the pressure above the anaerobic granular sludge reach 20-25 m of water column after the anaerobic reactor is filled with the nutrient solution, and the feeding amount of the nutrient solution is to fill the anaerobic reactor.

[0008] Preferably, the sludge concentration SVI in the anaerobic storage is 50-80 mL / g. 30

[0009] Preferably, the temperature condition for the sealed anaerobic reactor to be stored under the undisturbed anaerobic condition is 5-10 DEG C.

[0010] Another technical solution provided by the present application is a starting method of the anaerobic granular sludge stored by the above method, wherein the wastewater to be treated and the nutrient solution are mixed in a certain proportion and then added to the anaerobic reactor, the proportion of the wastewater in the mixed solution is gradually increased until 100%, and after 5-15 days, when the COD removal rate reaches 60-80% and the sludge concentration increases by 15-20%, the starting is successful.

[0011] Preferably, during the starting process, the concentration of the wastewater or the nutrient solution is adjusted to gradually increase the COD concentration from 3000 mg / l to not less than 20000 mg / l, and the volume load is gradually increased from 1.5 g / L·d to 3.5 g / L·d.

[0012] Preferably, during the starting process, the pressure of 20-25 m of water column is continuously maintained.

[0013] Preferably, during the starting process, the temperature is maintained at 30-35 DEG C.

[0014] Preferably, during the storage and starting process, the dissolved oxygen concentration is controlled at 0.10-0.20 mg / L.

[0015] Compared with the prior art, the present application has the following beneficial effects:

[0016] The anaerobic granular sludge storage and starting method has simple steps and is easy to operate, the anaerobic granular sludge still has activity and is not disintegrated after being stored for 1-2 years, can be started in 5-15 days, and has recovered performance, and is not easy to be hollowed after starting, which is beneficial to the application of production shutdown and intermittent operation. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The structure schematic view of the anaerobic reactor used in Example 1 is shown in the figure.

[0018] ​Figure 2 Anaerobic granular sludge sample well grown before storage in Example 1;

[0019] Figure 3 Anaerobic granular sludge sample after water discharge in Example 1;

[0020] Figure 4 Anaerobic granular sludge sample after start-up completion of storage in Example 1.

[0021] Figure: anaerobic reactor 1, gas inlet pipe 2, water inlet pipe 3, sampling pipe 4, water discharge pipe 5, anaerobic granular sludge 6, pressure relief valve 7. DETAILED DESCRIPTION

[0022] The anaerobic granular sludge storage method of the present application comprises the following steps: placing the anaerobic granular sludge to be stored in an anaerobic reactor (the anaerobic reactor can be a special reactor, or can be stored in situ if the conditions are met), discharging water after the anaerobic granular sludge is settled, adding the prepared nutrient solution, and the nutrient solution addition amount is higher than a certain height of the anaerobic granular sludge; finally, the pressure above the anaerobic granular sludge is made to reach 20-25 m of water column, and the anaerobic reactor is sealed for storage under undisturbed anaerobic conditions.

[0023] In a more preferred embodiment, the COD concentration in the nutrient solution is 5000-8000 mg / L, the carbon source includes sodium acetate or carbon-containing production wastewater, such as alcohol industry wastewater, starch industry wastewater, etc.; ammonium chloride is used as the nitrogen source, and the NH 4+ The -N concentration is 15-20 mg / L; potassium dihydrogen phosphate is used as the phosphorus source, and the concentration is 1-3 mg / L; the pH of the nutrient solution is 9-10.

[0024] The nutrient solution addition amount is preferably 30-50 cm higher than the anaerobic granular sludge, and the method for making the pressure above the anaerobic granular sludge reach 20-25 m of water column is nitrogen gas pressurization; if the height in the anaerobic reactor can just meet the pressure above the anaerobic granular sludge after being filled with the nutrient solution, the pressure reaches 20-25 m of water column, nitrogen gas pressurization can also be omitted, and the anaerobic reactor is filled with the nutrient solution.

[0025] Sludge concentration SVI in anaerobic storage 30 It is preferably 50-80 mL / g.

[0026] In order to further ensure the activity of the anaerobic granular sludge and prolong the storage time, more preferably, the temperature condition for storing the anaerobic reactor under undisturbed anaerobic conditions is 5-10℃, and the dissolved oxygen concentration is preferably controlled at 0.10-0.20 mg / L.

[0027] In-situ storage at least meets the air tightness and pressure conditions.

[0028] The anaerobic granular sludge stored by the above method can be started by the following method: the wastewater to be treated is mixed with the nutrient solution in a proportion, and then added to the anaerobic reactor, and the proportion of wastewater in the mixed solution is gradually increased to 100%. Further, during the starting process, the COD concentration is gradually increased from 3000 mg / l to not less than 20000 mg / l by adjusting the concentration of wastewater or nutrient solution, and the volumetric loading is gradually increased from 1.5 g / L·d to 3.5 g / L·d; from the start, after 5-15 days, when the COD removal rate reaches 60-80%, the sludge concentration increases by 15-20%, that is, the start is successful; more preferably, during the starting process, the temperature is maintained at 30-35℃, and the dissolved oxygen concentration is controlled at 0.10-0.20 mg / L.

[0029] In addition, during the starting process, it is advisable to continuously maintain a water column pressure of 20-25 m to avoid sludge breakage or enlargement and loss of activity.

[0030] Example 1

[0031] A petrochemical plant in Jiangsu mainly produces propylene oxide. Its wastewater is treated by an IC reactor, and the anaerobic sludge produced is mainly anaerobic granular sludge. Due to periodic market and product reasons, the plant has been shut down for about a year. Since there is no wastewater, the anaerobic granular sludge needs to be stored. The well-grown anaerobic granular sludge sample before storage is shown in Figure 2 .

[0032] Since the IC reactor is repaired during the shutdown period, the anaerobic granular sludge is pumped into a specially made reaction container, as shown in Figure 1 . The anaerobic reactor 1 is provided with an air inlet pipe 2 and a water inlet pipe 3 at the upper part, a vent pipe 5 at the lower part, and multiple sampling pipes 4 at different heights on the side, and a pressure relief valve 7 at the top. After the anaerobic granular sludge 6 is settled, the water is discharged by opening the vent pipe 5, and the sample is taken from the sampling pipe 4. The anaerobic granular sludge sample after water discharge is shown in Figure 3 .

[0033] The nutrient solution is configured with sodium acetate as the main carbon source, with a COD concentration of 8000 mg / L, ammonium chloride as the nitrogen source, with a NH 4+ -N concentration of 20 mg / L, and potassium dihydrogen phosphate as the phosphorus source, with a concentration of 3 mg / L, and pH 9-10. The prepared nutrient solution is added through the water inlet pipe 3, and the nutrient solution addition amount is 50 cm higher than the granular sludge, and the sludge concentration can reach SVI 30 of 70 mL / g.

[0034] After the above steps are completed, nitrogen is added from the air inlet pipe 2, the pressure is increased to 22 m of water column, all valves are closed, the dissolved oxygen concentration is controlled at 0.15 mg / L, the environmental temperature is controlled at 8℃, and the anaerobic storage is carried out without disturbance.

[0035] After storage for one year, the production was resumed, the anaerobic granular sludge was sampled from each sampling tube 4 after starting up by the method in the above embodiments, and the sample after completion of starting up of the stored anaerobic granular sludge was seen in Table 1 Figure 4 The anaerobic granular sludge did not have the hollowing phenomenon after starting up; the activity of the anaerobic granular sludge after starting up was almost the same as that before storage.

[0036] Example 2

[0037] A beer factory in Jiangsu Province, the wastewater anaerobic reaction used an IC reactor, and the anaerobic granular sludge was stored in situ and started up by the method in the above embodiments. The starting up method was to enter the produced beer wastewater and nutrient solution in proportion, the ratio of beer wastewater to nutrient solution was started from 1:5, and increased to 100% beer wastewater after 5 days. During the starting up process, the dissolved oxygen concentration was controlled to be 0.10-0.20 mg / L, the temperature was controlled to be 35℃, the volumetric loading was gradually increased from 1.5 g / L·d at the beginning of starting up to 3.5 g / L·d, the COD removal rate was gradually increased from 10% to 80%, the sludge concentration was increased by 20%, and the total time from starting up to successful starting up was 15 days.

[0038] Example 3

[0039] In the laboratory test, the well-grown anaerobic granular sludge was stored for 10 days by using the anaerobic reactor and method parameters of the same proportion in Example 1, and then started up. According to the method parameters in Example 2, the COD removal rate reached 60% when the sludge concentration increased by 15%, and the starting up was determined to be successful. The activity was basically restored by sampling test, and the same method was used for storage and starting up again after 5 days of wastewater treatment operation. After 3 rounds of repetition, samples were taken at different heights for observation, and no disintegration and hollowing phenomenon was found. The activity of the anaerobic granular sludge was normal.

[0040] The above is only a preferred embodiment of the present application, but the protection scope of the present application is not limited thereto, any changes or replacements within the technical range disclosed by the present application can be easily thought by those skilled in the art, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be limited by the protection scope defined by the claims.

[0041] The details not described in the present application are the known technology of those skilled in the art.

Claims

1. An anaerobic granular sludge storage method, characterized by, The method comprises the following steps: The anaerobic granular sludge to be stored is placed in an anaerobic reactor, water is drained after the anaerobic granular sludge is settled, the prepared nutrient solution is added, the addition amount of the nutrient solution is higher than the height of the anaerobic granular sludge, and finally the pressure above the anaerobic granular sludge is 20-25 m of water column, and the anaerobic reactor is sealed for storage under the condition of undisturbed anaerobic environment; The addition amount of the nutrient solution is 30-50 cm higher than the height of the anaerobic granular sludge, the method for making the pressure above the anaerobic granular sludge reach 20-25 m of water column is nitrogen charging and pressurizing, or the height of the anaerobic reactor is just enough to make the pressure above the anaerobic granular sludge reach 20-25 m of water column after the anaerobic reactor is filled with the nutrient solution, and the addition amount of the nutrient solution is to fill the anaerobic reactor.

2. The method of claim 1, wherein the anaerobic granular sludge is stored at a temperature of 10 to 40°C. The COD concentration in the nutrient solution is 5000-8000 mg / L, the carbon source includes sodium acetate or carbon-containing production wastewater; the ammonium chloride is used as the nitrogen source, the NH 4+ The -N concentration is 15-20 mg / L; the potassium dihydrogen phosphate is used as the phosphorus source, the concentration is 1-3 mg / L; and the pH of the nutrient solution is 9-10.

3. The method of claim 1, wherein: Sludge concentration in anaerobic storage SVI 30 is 50-80 mL / g.

4. The method of claim 1, wherein: The temperature condition for storing the sealed anaerobic reactor under the condition of undisturbed anaerobic environment is 5-10 DEG C.

5. A method for starting up anaerobic granular sludge storage using the method according to any one of claims 1 to 4, characterized by: The wastewater to be treated is mixed with the nutrient solution in a certain proportion, and then added into the anaerobic reactor, the proportion of the wastewater in the mixed solution is gradually increased until 100%, and after 5-15 days, when the COD removal rate reaches 60-80% and the sludge concentration increases by 15-20%, the start-up is successful.

6. The method of starting an anaerobic granular sludge according to claim 5, wherein: In the start-up process, the concentration of the wastewater or the nutrient solution is adjusted to gradually increase the COD concentration from 3000 mg / l to not less than 20000 mg / l, and the volume load is gradually increased from 1.5 g / L·d to 3.5 g / L·d.

7. The method of claim 5, wherein: In the start-up process, the 20-25 m of water column pressure is continuously maintained.

8. The method of claim 5, wherein: In the start-up process, the temperature is maintained at 30-35 DEG C.

9. The method of claim 5, wherein: In the storage and start-up process, the dissolved oxygen concentration is controlled at 0.10-0.20 mg / L.

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