Method for accelerating anaerobic sludge granulation treatment of pharmaceutical wastewater

Abstract

A method for accelerating anaerobic sludge granulation treatment of pharmaceutical wastewater belongs to the technical field of wastewater treatment, and the specific scheme comprises the following steps: step 1, taking acclimatized active sludge with tolerance to pharmaceutical wastewater, and inoculating the acclimatized active sludge into a UASB reactor; step 2, adding a resin-based material into the UASB reactor, standing and precipitating for 24-48 hours, introducing pharmaceutical wastewater into the UASB reactor, and enabling the reactor to operate normally; and step 3, after the reactor runs for 150-180 days, adding 6 + / -1g / L of ferroferric oxide and 1.5 + / -0.5 g / L of calcium chloride, and strengthening methane production activity and anaerobic sludge granulation. Under the stress of high toxicity and high salt of pharmaceutical wastewater, the resin-based material is used for inducing anaerobic sludge granulation, and the granulation process is accelerated. The anaerobic biological treatment technology of pharmaceutical wastewater is applied, and the anaerobic sludge granulation starting time can be shortened by 30% or above.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a method for accelerating anaerobic sludge granulation to treat pharmaceutical wastewater. Background Art

[0002] Pharmaceutical wastewater is generally complex in composition, high in organic matter content, highly toxic, and its pollutants are usually difficult to biodegrade. With the continuous development of my country's pharmaceutical industry, pharmaceutical wastewater has become one of the main sources of pollution. Practice has shown that there is no mature and unified management method for pharmaceutical wastewater, there are many types of pharmaceutical raw materials and processes, the quality of wastewater discharge is also different, and there is a lack of unified treatment methods. High-concentration pharmaceutical wastewater usually adopts an anaerobic-aerobic combination process. Anaerobic biological treatment can provide a suitable substrate concentration for subsequent aerobic treatment, so the successful start-up of anaerobic biological treatment is crucial. Because wastewater often contains inhibitory substances, the anaerobic biological reaction process has problems such as difficulty in starting and low degree of anaerobic sludge granulation. The long start-up time is one of the main obstacles to the practice of anaerobic granulation in this field, and the granulation results cannot be guaranteed. Pharmaceutical wastewater is characterized by high toxicity and high salt content. The high osmotic pressure caused by high salinity will inhibit microbial activity, and high density will also affect the sludge sedimentation performance. The residual drugs in the wastewater will also poison the microorganisms, thereby affecting the formation of sludge. Under the stress of high toxicity and high salt content, the anaerobic biological treatment effect is not good. Therefore, how to accelerate the granulation of anaerobic sludge in pharmaceutical wastewater is a research hotspot. Summary of the invention

[0003] In order to solve the technical problems of the difficulty in starting up and the low degree of anaerobic sludge granulation in the anaerobic-aerobic combination process used for high-concentration pharmaceutical wastewater in the prior art, the present invention provides a method for accelerating anaerobic sludge granulation to treat pharmaceutical wastewater.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for accelerating anaerobic sludge granulation to treat pharmaceutical wastewater, comprising the following steps:

[0006] Step 1, taking activated sludge that has been tamed and is tolerant to pharmaceutical wastewater and inoculating it into a UASB reactor;

[0007] Step 2: Add resin-based materials to the UASB reactor, let it settle for 24-48 hours, then introduce pharmaceutical wastewater into the UASB reactor, and the reactor operates normally;

[0008] Step 3: After the reactor has been running for 150-180 days, 6±1 g / L of ferroferric oxide and 1.5±0.5 g / L of calcium chloride are added to enhance the methanogenic activity and strengthen the anaerobic sludge granulation.

[0009] Furthermore, in step 1, the concentration of activated sludge in the UASB reactor is 10000-11000 mg / L.

[0010] Furthermore, in step 1, the effective volume of the UASB reactor is 3.5L.

[0011] Furthermore, in step 2, the volume of the added resin-based material is 5-10% of the volume of the UASB reactor.

[0012] Furthermore, in step 2, the resin-based material is ultrasonically cleaned before being added.

[0013] Furthermore, the hydraulic retention time HRT of the UASB reactor is 24h, the rising flow rate is 0.4-2m / h, and the temperature is controlled at 35-38°C.

[0014] Furthermore, sodium bicarbonate was added to the UASB reactor to control the pH in the reactor to be 7-7.5.

[0015] Furthermore, water enters the side of the UASB reactor and refluxes at the bottom.

[0016] Furthermore, the COD concentration of the pharmaceutical wastewater is 3500-4500 mg / L.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention discloses a method for accelerating anaerobic sludge granulation to treat pharmaceutical wastewater. Under the high toxicity and high salt stress of pharmaceutical wastewater, resin-based materials are used to induce anaerobic sludge granulation to accelerate the granulation process. The present invention uses anaerobic biological treatment technology for pharmaceutical wastewater to shorten the start-up time of anaerobic sludge granulation by more than 30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The changes in sludge particle size distribution at different time periods, Figure a is for 65 days of operation, Figure b is for 90 days of operation, Figure c is for 105 days of operation, Figure d is for 133 days of operation, Figure e is for 157 days of operation, and Figure f is for 162 days of operation; Ceftriaxone sodium was added to the UASB reactor on the 90th day of operation, wherein 1# represents a blank group reactor without adding resin-based materials in step 2, 2# represents a reactor in which PE materials are added to replace resin-based materials in step 2, 3# represents a reactor in which resin-based materials are added in step 2, and 4# represents a reactor in which carbon-based activated carbon is added to replace resin-based materials in step 2;

[0020] Figure 2 is the COD change at each stage of continuous operation of the UASB reactor in Example 1;

[0021] Figure 3This is the gas production situation of the UASB reactor in Example 1. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the invention, rather than 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 work are within the scope of protection of the present invention.

[0023] Embodiment 1:

[0024] This sewage treatment technology uses wastewater containing ceftriaxone sodium that simulates pharmaceutical wastewater as the object, and is mainly based on the use of resin-based materials to induce anaerobic sludge granulation under high toxicity and high salt stress to accelerate the granulation process. Aiming at the practical problem that long startup is one of the main obstacles to practicing anaerobic granulation in this field, anaerobic sludge granulation includes two steps, namely nucleation and nucleus maturation. Nucleation as a starting point is particularly important. The present invention adopts a method of adding resin-based material particles to promote anaerobic sludge granulation.

[0025] The specific steps include:

[0026] Step 1, optimize the operating conditions. Take the activated sludge that has been acclimated and has a certain tolerance to pharmaceutical wastewater and inoculate it into the UASB reactor. The effective volume of each reactor is 3.5L, and the sludge concentration is 10000-11000mg / L.

[0027] Step 2, cleaning of resin-based materials. Take a certain amount of resin-based materials and add them to a 1L plastic bucket. Add deionized water to the bucket to immerse the resin-based materials. Wash them in an ultrasonic cleaner for 15 minutes. Repeat the cleaning three times. Measure the pH value to be 7.

[0028] Step 3, adding 5% volume of resin-based material into the UASB reactor, letting it settle for 48 hours, and then introducing pharmaceutical wastewater into the UASB reactor, and the reactor operates normally.

[0029] Step 4: After the reactor has been running for 180 days, 6 g / L of ferroferric oxide and 1.5 g / L of calcium chloride are added to enhance the methanogenic activity and strengthen the anaerobic sludge granulation.

[0030] Further details on the above scheme:

[0031] (1) In step 3, the highly toxic and high-salt pharmaceutical wastewater was prepared with glucose as the main carbon source and ceftriaxone sodium as the characteristic pollutant. Ammonium chloride (370 mg / L) and potassium dihydrogen phosphate (88 mg / L) were used as nitrogen and phosphorus sources in the pharmaceutical wastewater, and mineral salts (1.2 mg / L calcium chloride, 0.9 mg / L ferrous sulfate, 3 mg / L magnesium sulfate, 0.06 mg / L ferric chloride, 0.03 mg / L manganese chloride, 0.03 mg / L manganese chloride, 0.03 mg / L manganese sulfate ... g / L zinc chloride, 0.03mg / L copper chloride, 0.03mg / L aluminum chloride, 0.03mg / L cobalt chloride, 0.03mg / L nickel chloride and 0.018mg / L sodium platinate) as trace elements to meet the needs of microorganisms for macroelements and trace elements, the COD concentration of the pharmaceutical wastewater is 3500-4500mg / L, the cephalosporin concentration is 500mg / L, and sodium bicarbonate is added to control the pH in the reactor to 7-7.5;

[0032] (2) In step 4, the negatively charged microorganisms on the surface react with Fe 2+ / Fe 3+ It shows stronger affinity, and the dissimilatory effect of iron ions can also enhance the electron transfer activity of microorganisms; after adding CaCl2, the Ca in ionic form + After entering the anaerobic system, it will combine tightly with the negatively charged EPS to make the sludge particles more compact and cause the bacterial particles to settle to increase the biomass. This will enhance the stability of the granular sludge and help form a stable and dense three-dimensional sludge structure.

[0033] (3) The hydraulic retention time (HRT) of the UASB reactor is 24 h, the rising velocity is 0.4-2 m / h, and the temperature is controlled at 35-38 °C using a temperature control device.

[0034] (4) The anaerobic UASB system is prone to clogging. Filter chips can be added to the effluent and bottom, and the pipes should be cleared regularly.

[0035] (5) There are no special requirements for the water inlet method of the UASB reactor. In order to ensure the upward flow rate, the method of bottom reflux and side water inlet is selected.

[0036] The UASB reactor based on resin-based material induction disclosed in this embodiment can operate stably and has been continuously operated for more than 300 days. The COD of the influent gradually increases over time, and the treatment effect is stable. Figure 1 shown.

[0037] The sludge particle sizes vary. When glucose is used as the only carbon source, the particle size distributions of the four reactors are relatively similar (Figure a and Figure b). Figure 1As shown in a (reactor operation 65 days), the particle size of the sludge in the blank reactor 1# is concentrated in the range of 40-317um, with a maximum particle size of 1262um, and the particle size of the sludge in the reactor 3# with the addition of resin-based materials is concentrated in the range of 32-178um, with a maximum particle size of 1783um; under the continuous operation of the reactor, due to the continuous scouring of the hydraulic force, as shown in Figure 1 As shown in Figure 1 (90 days of operation), the granular sludge in the reactor gradually formed. The particle size of the blank 1# reactor sludge was concentrated in 78-562um, with a maximum particle size of 1262um. The particle size of the 3# reactor sludge with the addition of resin-based materials was concentrated in 50-317um, with a maximum particle size of 1783um. Figures a and b are sludge acclimation preparations. After the addition of ceftriaxone sodium (Figure c, 105 days of operation), the sludge in the 1# and 2# reactors showed a particularly obvious trend of granulation disintegration, especially the large granular sludge. The disintegration of the granular sludge in the 3# reactor was mainly concentrated in small-sized particles, and the disintegration of the granular sludge in the 4# reactor was mainly concentrated in large-sized particles. The anaerobic sludge granulation in the 3# reactor had strong resistance to salinity and load shock. In this study, the granulation time of adding resin-based materials in a highly toxic and high-salt wastewater system was short and had strong resistance to salinity and load shock. It is speculated that the reason is that the resin-based material directly forms large-sized sludge particles as the core.

[0038] like Figure 2 As shown, the influent COD was 3500-4500 mg / L in the initial stage. After 5 stages of operation, the effluent COD of the 1# blank reactor was 1600±300 mg / L, and the effluent COD of the 3# reactor with resin-based materials was 400±100 mg / L. At this time, the COD removal rate of the 1# reactor was stabilized at about 60%, and the COD removal rate of the 3# reactor was stabilized at more than 85%.

[0039] like Figure 3 As shown, when the reactor produces gas stably, the average daily gas production of the 3# reactor reaches 2386 ml / d (period without adding cephalosporin) and 1908 ml / d (period with adding cephalosporin), of which the methane production is 501.06 ml / d (period without adding cephalosporin) and 401 ml / d (period with adding cephalosporin), and the methane production efficiency is very high; the average daily gas production of the 1# reactor is 1425 ml / d (period without adding cephalosporin) and 468 ml / d (period with adding cephalosporin), of which the methane production is 413.25 ml / d (period without adding cephalosporin) and 124.54 ml / d (period with adding cephalosporin).

[0040] The gas production is easily affected by the influent quality. When the gas production is stable, the production efficiency of the 3# reactor is higher, and the 3# reactor shortens the cultivation time. According to the mechanism of anaerobic sludge granulation, the resin-based material becomes the core of the newly formed granular sludge, which can shorten the cultivation time of sludge granulation; the addition of resin-based materials can increase the salinity resistance of anaerobic sludge and resist the impact of toxic substances. The disintegration of large-sized anaerobic sludge particles under high toxicity and high salt stress is the main reason for the decline in methane production capacity. The resin-based material as the core of the newly formed granular sludge can effectively alleviate the disintegration of large-sized anaerobic sludge particles, making it have good salinity resistance and toxicity resistance, and solve the problem of slow startup or even startup failure when anaerobic biotechnology treats high-salt and high-toxic pharmaceutical wastewater.

[0041] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for accelerating anaerobic sludge granulation to treat pharmaceutical wastewater, characterized in that: The following steps are involved: Step 1, taking activated sludge that has been tamed and is tolerant to pharmaceutical wastewater and inoculating it into a UASB reactor; Step 2: Add resin-based materials to the UASB reactor, let it settle for 24-48 hours, then introduce pharmaceutical wastewater into the UASB reactor, and the reactor operates normally; Step 3: After the reactor has been running for 150-180 days, 6±1 g / L of ferroferric oxide and 1.5±0.5 g / L of calcium chloride are added to enhance the methanogenic activity and strengthen the anaerobic sludge granulation.

2. The method for accelerating anaerobic sludge granulation to treat pharmaceutical wastewater according to claim 1, characterized in that: In step 1, the concentration of activated sludge in the UASB reactor is 10000-11000 mg / L.

3. The method for accelerating anaerobic sludge granulation to treat pharmaceutical wastewater according to claim 1, characterized in that: In step 1, the effective volume of the UASB reactor is 3.5L.

4. The method for accelerating anaerobic sludge granulation to treat pharmaceutical wastewater according to claim 1, characterized in that: In step 2, the volume of the added resin-based material is 5%-10% of the volume of the UASB reactor.

5. The method for accelerating anaerobic sludge granulation to treat pharmaceutical wastewater according to claim 1, characterized in that: In step 2, the resin-based material is ultrasonically cleaned before being added.

6. The method for accelerating anaerobic sludge granulation to treat pharmaceutical wastewater according to claim 1, characterized in that: The hydraulic retention time HRT of the UASB reactor is 24h, the rising flow rate is 0.4-2m / h, and the temperature is controlled at 35-38°C.

7. The method for accelerating anaerobic sludge granulation to treat pharmaceutical wastewater according to claim 1, characterized in that: Sodium bicarbonate was added to the UASB reactor to control the pH in the reactor to 7-7.

5.

8. The method for accelerating anaerobic sludge granulation to treat pharmaceutical wastewater according to claim 1, characterized in that: The UASB reactor has water inlet at the side and reflux at the bottom.

9. The method for accelerating anaerobic sludge granulation to treat pharmaceutical wastewater according to claim 1, characterized in that: The COD concentration of the pharmaceutical wastewater is 3500-4500 mg / L.

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