Efficient low-energy-consumption treatment method and system for gelatin wastewater

Abstract

The invention provides a high-efficiency low-energy-consumption treatment method and system for gelatin wastewater. The treatment method comprises the following steps: sequentially carrying out primary hydrolytic acidification, secondary hydrolytic acidification, biological decalcification and biochemical treatment on the wastewater, wherein the biological decalcification and the biochemical treatment are A2O processes, and the wastewater is treated by using an anaerobic tank, an anoxic tank and an aerobic tank containing activated sludge. Through a complete process consisting of two-stage hydrolytic acidification and two-stage aerobic treatment, organic nitrogen in the gelatin wastewater can be efficiently converted, the influence of calcium ions on microorganisms is reduced, the content of organic pollutants and the content of ammonia nitrogen in the wastewater are effectively reduced, and the sewage treatment effect is good; and residual sludge is recycled for resourceful treatment, so that the treatment cost is reduced, and resource recycling is promoted.

Description

Technical Field

[0001] The present application relates to the technical field of sewage treatment, and in particular to a high-efficiency and low-energy consumption treatment method and system for gelatin wastewater. Background Art

[0002] Gelatin is a protein macromolecule obtained by boiling collagen-containing tissues such as animal skins, bones, horns, horns and scales after a series of chemical treatments such as acid and alkali soaking. It is widely used in photography, food, medical treatment, adhesives, etc. due to its superior physical and chemical properties. The water consumption of gelatin production is extremely large, the total amount of pollutants is high, the wastewater discharge is large, and the water quality is very complex. The wastewater from gelatin production has high calcium, high alkali, high organic pollutant content, high protein, and may also contain high chloride ions, sulfides, etc., which makes the treatment of gelatin wastewater difficult and the treatment cost high, which is harmful to human production, life and ecological environment.

[0003] When gelatin wastewater is discharged into farmland soil, its high calcium and high alkalinity characteristics cause serious soil salinization and increase fertilizer costs; when gelatin wastewater is discharged into rivers, its pH value will increase, causing the death of aquatic animals, and at the same time, it will reduce the transparency of the water body and harm the surrounding environment. The difficulty in treating gelatin wastewater has greatly hindered the production efficiency of gelatin companies and has become a problem that troubles gelatin workers. How to use reasonable process technology to treat gelatin production wastewater economically and effectively is a problem that gelatin production companies must face and is also the direction of continuous efforts in the future.

[0004] There are mainly physical treatment, chemical treatment, biological treatment and other methods for the treatment of gelatin wastewater. However, due to the characteristics of gelatin wastewater, the physical and chemical methods are costly and easily cause secondary pollution. In the biological treatment method, high calcium and high chlorine can easily inhibit microorganisms and affect the efficiency of biological treatment. A single process for treating gelatin wastewater sometimes cannot achieve good treatment results. Therefore, how to improve the efficiency of biological treatment of gelatin wastewater has become one of the focuses of gelatin wastewater treatment. Summary of the invention

[0005] The present application provides a method and system for treating gelatin wastewater with high efficiency and low energy consumption to solve the problems existing in the related technologies. The technical solution is as follows:

[0006] In a first aspect, the present application provides a method for treating gelatin wastewater with high efficiency and low energy consumption, comprising the following steps:

[0007] The wastewater is sequentially subjected to primary hydrolysis and acidification, secondary hydrolysis and acidification, biological decalcification, and biochemical treatment; wherein the biological decalcification and biochemical treatment are A 2 O process, comprising using an anaerobic tank, an anoxic tank and an aerobic tank containing activated sludge to treat the wastewater.

[0008] In one embodiment, before the primary hydrolysis and acidification, concentrated sulfuric acid is added to the wastewater with stirring to adjust the pH of the wastewater; and then the wastewater is allowed to settle.

[0009] In one embodiment, the conditions of the primary hydrolysis acidification are: acidification in an expanded sludge bed at a pH of 9-10 for 5-7 hours; dissolved oxygen is controlled at DO < 0.5 mg / L, and the volumetric load of the primary hydrolysis acidification is 5.5-7 kg COD / (m 3 ·d).

[0010] In one embodiment, the conditions for the secondary hydrolysis acidification are: acidification in an expanded sludge bed for 9 to 13 hours; the dissolved oxygen is controlled at DO < 0.5 mg / L, and the volumetric load of the secondary hydrolysis acidification is 2 to 3 kg COD / (m 3 ·d).

[0011] In one embodiment, in the biological decalcification, the dissolved oxygen in the anaerobic tank is <0.2 mg / L, and the dissolved oxygen in the anoxic tank is <0.5 mg / L.

[0012] In one embodiment, the pH of the aerobic pool is 8-9; the aeration air volume of the aerobic pool is controlled to be 25-30m 3 / h, dissolved oxygen is 1-3mg / L; aerobic pool sludge concentration is 35-45g / L, MLVSS / MLSS is 15-25%.

[0013] In one embodiment, the biological decalcification process further includes sedimentation, and the wastewater after the aerobic tank treatment enters the sedimentation tank for sedimentation.

[0014] In one embodiment, the gas supply volume of the sedimentation tank gas stripping reflux is 15-25m 3 / h, the reflux rate is 100%-150%; the mass ratio of sludge reflux rate to residual sludge is 2-4:6-8.

[0015] In one embodiment, in the biochemical treatment, the dissolved oxygen in the anaerobic tank is <0.2 mg / L, and the dissolved oxygen in the anoxic tank is <0.5 mg / L.

[0016] In one embodiment, the pH of the aerobic pool is 7-8; the aeration air volume of the aerobic pool is 22-28m 3 / h, dissolved oxygen is 2-4mg / L; aerobic pool sludge concentration is 4-6g / L, MLVSS / MLSS is 65-80%.

[0017] In one embodiment, the time ratio of biological decalcification treatment to biochemical treatment is 2:3 to 1:2.

[0018] In one embodiment, after the wastewater after biochemical treatment is precipitated, the supernatant is the treated qualified wastewater.

[0019] In a second aspect, the embodiment of the present application provides a high-efficiency and low-energy consumption treatment system for gelatin wastewater, including a primary hydrolysis acidification tank, a secondary hydrolysis acidification tank, a biological decalcification unit, and a biochemical treatment unit connected in sequence;

[0020] The biological decalcification unit comprises a first anaerobic tank, a first anoxic tank, a first aerobic tank and a first sedimentation tank which are connected in sequence;

[0021] The biochemical treatment unit comprises a second anaerobic tank, a second anoxic tank and a second aerobic tank which are connected in sequence.

[0022] In one embodiment, a regulating tank is further provided before the primary hydrolysis tank, and the regulating tank comprises a stirring zone and a static zone which are connected in sequence; the static zone is connected to the primary hydrolysis acidification tank;

[0023] The biochemical treatment unit also includes a second sedimentation tank and a clean water tank which are connected in sequence, and the second aerobic tank of the biochemical treatment unit is connected to the second sedimentation tank;

[0024] The first aerobic tank and the second aerobic tank are respectively provided with an aeration device;

[0025] The first sedimentation tank and the second sedimentation tank are respectively provided with a gas stripping reflux device.

[0026] The advantages or beneficial effects of the above technical solution include at least:

[0027] The present application provides a high-efficiency and low-energy consumption treatment method for gelatin wastewater. After hydrolysis and acidification, the wastewater is subjected to biological decalcification and biochemical treatment. Hydrolysis and acidification degrade macromolecular organic matter into small molecular organic matter, providing high-quality carbon source for subsequent biochemical treatment; it can also efficiently convert organic nitrogen in gelatin wastewater, reduce the organic load of subsequent biochemical treatment, and reduce the output of biochemical sludge. Biological decalcification avoids the addition of a large amount of chemical agents, reduces the cost of decalcification of gelatin wastewater, and avoids secondary pollution; and by decalcification, the toxic effect of calcium ions on microorganisms in the biochemical system is reduced, more abundant dominant microorganisms are enriched, the treatment effect is better, and standard discharge is achieved. The complete set of processes consisting of hydrolysis and acidification and a secondary aerobic stage can efficiently convert organic nitrogen in gelatin wastewater, reduce the impact of calcium ions on microorganisms, effectively reduce the content of organic pollutants and ammonia nitrogen in wastewater, and have a good sewage treatment effect; the residual sludge is recycled for resource treatment, reducing treatment costs and recycling resources.

[0028] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0030] Figure 1 The sludge properties in the aerobic tank for biological decalcification and biochemical treatment for this application are shown in the figure;

[0031] Figure 2 This is a graph showing the change in COD content in wastewater at each treatment stage in the embodiment of the present application;

[0032] Figure 3 This is a graph showing changes in ammonia nitrogen content in wastewater at various treatment stages in the embodiment of the present application;

[0033] Figure 4 This is a graph showing changes in total nitrogen content in wastewater during the biochemical treatment phase of this application;

[0034] Figure 5 The graph of COD content change in wastewater at each treatment stage in Comparative Example 1;

[0035] Figure 6 This is a graph showing changes in ammonia nitrogen content in wastewater at various treatment stages in Comparative Example 1;

[0036] Figure 7 This is a graph showing the change in total nitrogen content in wastewater during the biochemical treatment phase of Comparative Example 1;

[0037] Figure 8 The Venn diagram and diversity index diagram of species composition in sludge from aerobic pools for biological decalcification treatment, biochemical treatment, and raw wastewater treatment;

[0038] Fig. 9 It is a bar chart of species composition in the sludge of the aerobic tank for biological decalcification treatment, biochemical treatment and raw wastewater treatment. DETAILED DESCRIPTION

[0039] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present application. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0040] Gelatin production wastewater has high calcium, high alkali, high organic pollutant content, high protein, and may also contain high chloride ions, sulfides, etc.; the existing gelatin wastewater treatment has problems such as difficult wastewater treatment, high treatment cost, low treatment efficiency, poor denitrification effect, low microbial activity, and large amount of residual sludge discharge.

[0041] Therefore, the present application provides a high-efficiency and low-energy consumption treatment method for gelatin wastewater, comprising the following steps:

[0042] The wastewater is sequentially subjected to primary hydrolysis and acidification, secondary hydrolysis and acidification, biological decalcification, and biochemical treatment; wherein the biological decalcification and biochemical treatment are A 2 O process, comprising using an anaerobic tank, an anoxic tank and an aerobic tank containing activated sludge to treat the wastewater.

[0043] Through primary hydrolysis and acidification and secondary hydrolysis and acidification, organic nitrogen is converted into ammonia nitrogen, while some organic pollutants in the wastewater are consumed, the COD of the effluent is reduced, the pH value of the wastewater is reduced, and easily degradable organic pollutants are provided for subsequent biochemical treatment. Biological decalcification uses the method of biological decalcification, which does not require the addition of a large amount of chemical agents to remove calcium ions, reduces the cost of decalcification of gelatin wastewater, and avoids secondary pollution. It is important to reduce the toxic effect of calcium ions on microorganisms in the biochemical system, enrich more abundant dominant microorganisms, make the subsequent biochemical treatment effect better, and achieve standard discharge. Therefore, the complete process consisting of two-stage hydrolysis and acidification and secondary aerobic treatment can efficiently convert organic nitrogen in gelatin wastewater, reduce the impact of calcium ions on microorganisms, effectively reduce the content of organic pollutants and ammonia nitrogen in wastewater, and achieve good sewage treatment effect.

[0044] As one implementation method, before the primary hydrolysis and acidification, concentrated sulfuric acid is added to the wastewater and stirred to adjust the pH value of the wastewater; and then the wastewater is allowed to stand and settle.

[0045] Adding concentrated sulfuric acid to gelatin wastewater, on the one hand, adjusts the pH value to the pH value required by the subsequent treatment method, and on the other hand, concentrated sulfuric acid provides a large amount of sulfate ions, which can form calcium sulfate crystals with calcium ions. When the wastewater is left standing, the calcium sulfate crystals are precipitated and deposited at the bottom of the pool.

[0046] In this embodiment, the pH value is set to a range of 9-10, that is, the pH of the wastewater is adjusted to 9-10 by concentrated sulfuric acid.

[0047] Furthermore, the addition of concentrated sulfuric acid and the adjustment of pH can be automatically achieved through a pH detection probe and an automatic dosing system.

[0048] As one embodiment, the conditions of the primary hydrolysis acidification are: acidification in an expanded sludge bed at a pH of 9-10 for 5-7 hours; dissolved oxygen is controlled at DO < 0.5 mg / L, and the primary hydrolysis volume load is 5.5-7 kg COD / (m 3 ·d).

[0049] After the wastewater is conditioned in a regulating tank to adjust the pH value and allowed to settle to initially remove calcium ions, it is subjected to primary hydrolysis and acidification treatment. In the primary hydrolysis and acidification treatment, the sludge and water are fully mixed through the water distribution system and the sludge expansion bed, and part of the organic nitrogen in the wastewater is converted into ammonia nitrogen under the action of hydrolytic microorganisms. At the same time, the primary hydrolysis and acidification can resist some water inflow shocks and also has a certain detoxification effect, providing a basis for subsequent biochemical treatment.

[0050] Specifically, the primary hydrolysis and acidification treatment time is 5 to 7 hours. Hydrolysis and acidification can convert organic nitrogen in the wastewater into ammonia nitrogen, and the dissolved oxygen in the hydrolysis section is controlled at DO < 0.5 mg / L.

[0051] In this embodiment, the water inflow is adjusted in time, and the volume load of the first-stage hydrolysis acidification is 5.5-7 kg COD / (m 3 ·d); Through primary hydrolysis and acidification treatment, the organic nitrogen conversion efficiency is 50% to 80%.

[0052] As one embodiment, the conditions for the secondary hydrolysis acidification are: acidification in the expanded sludge bed for 9 to 13 hours; the dissolved oxygen is controlled at DO < 0.5 mg / L, and the volumetric load of the secondary hydrolysis acidification is 2 to 3 kg COD / (m 3 ·d).

[0053] The wastewater undergoes primary hydrolysis and acidification treatment and then secondary hydrolysis and acidification treatment, where it fully reacts with microorganisms in the sludge expansion bed to convert all organic nitrogen in the wastewater into ammonia nitrogen. At the same time, it consumes some organic pollutants in the wastewater, reduces the COD of the effluent, and reduces the pH value of the wastewater, providing easily degradable organic pollutants for subsequent biochemical treatment.

[0054] Specifically, the secondary hydrolysis acidification treatment time is 9-13h. The secondary hydrolysis acidification can convert all organic nitrogen in the wastewater into ammonia nitrogen, and the dissolved oxygen in the hydrolysis section is controlled at DO<0.5mg / L.

[0055] In this embodiment, the water inflow is adjusted in time, and the secondary hydrolysis volume load is 2-3 kg COD / (m 3 ·d); Through secondary hydrolysis and acidification treatment, the organic nitrogen conversion efficiency is 20% to 50%, and the organic pollutant removal rate is 10% to 25%.

[0056] As one embodiment, in the biological decalcification, A 2 O process, comprising using a first anaerobic tank, a first anoxic tank and a first aerobic tank containing activated sludge to treat the wastewater.

[0057] The wastewater after the hydrolysis and acidification stage is subjected to biological decalcification, and first enters the first anaerobic tank and the first anoxic tank for treatment to remove some nitrogen and organic matter. In this embodiment, the dissolved oxygen in the first anaerobic tank is less than 0.2 mg / L, and the dissolved oxygen in the first anoxic tank is less than 0.5 mg / L.

[0058] The wastewater then enters the first aerobic tank for treatment. In the first aerobic tank, aeration control and pH adjustment are used to promote the full combination of calcium ions and carbonate ions in the wastewater to form calcium carbonate precipitation, thereby removing most of the calcium ions in the wastewater.

[0059] In this embodiment, the pH of the first aerobic pool is 8-9; the aeration air volume of the first aerobic pool is controlled to be 25-30m 3 / h, dissolved oxygen is 1-3mg / L; the sludge concentration in the first aerobic tank is 35-45g / L, and MLVSS / MLSS is 15-25%.

[0060] As one embodiment, the first aerobic pool is further provided with an aeration device and a pH adjustment device. Preferably, a perforated aeration pipe is used for continuous aeration.

[0061] As one embodiment, the biological decalcification process further includes a precipitation step, which is performed in a first sedimentation tank, and the wastewater treated in the first aerobic tank enters the first sedimentation tank for precipitation.

[0062] In this embodiment, high-calcium sludge is returned by air lift, and at the same time, the high-calcium sludge is screened by a hydrocyclone device on the return pipe to increase the calcium content of the sludge at the underflow port to facilitate calcium recycling and increase the organic sludge content at the overflow port to facilitate its return for biochemical treatment.

[0063] The gas supply volume of the sedimentation tank is 15-25m 3 / h, the reflux rate is 100%-150%; the mass ratio of sludge reflux rate to residual sludge is 2-4:6-8.

[0064] After the gelatin wastewater is treated with biological decalcification, most of the calcium ions in the water are removed and then biochemical treatment is carried out.

[0065] As one embodiment, in the biochemical treatment, A 2 O process, comprising using a second anaerobic tank, a second anoxic tank and a second aerobic tank containing activated sludge to treat the wastewater.

[0066] The wastewater after biological decalcification is biochemically treated and first enters the second anaerobic tank and the second anoxic tank for treatment. After biological decalcification, the reduction of calcium ions in the wastewater reduces the inhibitory effect of calcium ions on microorganisms in biochemical treatment, promotes the enrichment of microorganisms, and the enriched dominant microorganisms remove organic matter and nitrogen in the wastewater; the organic content of the sludge in the second aerobic tank increases, the biomass increases, the sludge concentration decreases, the sludge load increases, and the treatment efficiency is enhanced.

[0067] In this embodiment, the dissolved oxygen in the second anaerobic tank is less than 0.2 mg / L, and the dissolved oxygen in the second anoxic tank is less than 0.5 mg / L. The removal rate of organic matter and nitrogen is 70%-90%;

[0068] The wastewater then enters the second aerobic tank for treatment, passes through the second anaerobic tank and the second anoxic tank, and is fully mixed with the nitrification liquid from the second aerobic tank for denitrification reaction. The nitrate in the wastewater is converted into nitrogen gas and then discharged. The denitrified wastewater enters the aerobic tank for nitrification reaction to provide nitrate for further denitrification reaction.

[0069] In this embodiment, the pH of the second aerobic pool is 7-8; the aeration air volume of the second aerobic pool is 22-28m 3 / h, dissolved oxygen is 2-4mg / L; the sludge concentration in the second aerobic tank is 4-6g / L, and MLVSS / MLSS is 65-80%.

[0070] As one embodiment, the first aerobic pool is further provided with an aeration device and a pH adjustment device. Preferably, microporous aeration tubes are used for continuous aeration.

[0071] As one embodiment, the time ratio of biological decalcification treatment to biochemical treatment is 2:3 to 1:2.

[0072] As one of the implementation methods, after the wastewater after biochemical treatment is precipitated, the supernatant is the treated qualified wastewater and can be recycled.

[0073] The present application also provides a high-efficiency and low-energy consumption treatment system for gelatin wastewater, comprising a primary hydrolysis acidification tank, a secondary hydrolysis acidification tank, a biological decalcification unit, and a biochemical treatment unit connected in sequence;

[0074] The biological decalcification unit comprises a first anaerobic tank, a first anoxic tank, a first aerobic tank and a first sedimentation tank which are connected in sequence;

[0075] The biochemical treatment unit comprises a second anaerobic tank, a second anoxic tank and a second aerobic tank which are connected in sequence.

[0076] As one embodiment, a regulating tank is further provided before the primary hydrolysis tank, and the regulating tank includes a stirring zone and a static zone connected in sequence; the static zone is connected to the primary hydrolysis acidification tank;

[0077] The primary biochemical treatment unit also includes a second sedimentation tank and a clean water tank which are connected in sequence, and the second aerobic tank of the primary biochemical treatment unit is connected to the second sedimentation tank;

[0078] The first aerobic tank and the second aerobic tank are respectively provided with an aeration device;

[0079] The first sedimentation tank and the second sedimentation tank are respectively provided with a gas stripping reflux device.

[0080] The present application provides the following specific embodiments for further explanation.

[0081] Example

[0082] The gelatin wastewater enters the regulating tank and first enters the stirring zone. The pH upper and lower limits are set to 9-10. The pH of the wastewater is adjusted by adding concentrated sulfuric acid. Then the wastewater enters the static zone. The calcium sulfate crystals formed after adding sulfuric acid are precipitated and deposited at the bottom of the tank. The sludge is discharged into the sludge concentration tank through the sludge discharge pipe.

[0083] After passing through the regulating tank, the wastewater enters the primary hydrolysis acidification tank, and the retention time of the primary hydrolysis acidification tank is 5-7h. After being regulated in the primary hydrolysis acidification tank, the wastewater enters the secondary hydrolysis acidification tank, and the retention time of the secondary hydrolysis acidification tank is 9-13h. A pH probe is installed in the hydrolysis acidification section to monitor the pH fluctuation of the influent in real time, and to adjust the dosage of the front-end regulating tank and the influent in time. The dissolved oxygen in the hydrolysis section is controlled at DO<0.5mg / L, and the volume load of the primary hydrolysis acidification is 5.5-7kg COD / (m 3 ·d), the volumetric load of secondary hydrolysis acidification is 2~3kg COD / (m 3 ·d) The pH of the effluent from the hydrolysis and acidification stage is controlled at 8-9;

[0084] The wastewater after hydrolysis and acidification treatment enters the biological decalcification, first entering the first anaerobic tank and the first anoxic tank to remove some nitrogen and organic matter. The dissolved oxygen in the first anaerobic tank is <0.2mg / L, and the dissolved oxygen in the first anoxic tank is <0.5mg / L; then it enters the first aerobic tank. The pH of the first aerobic tank is controlled at 8-9; the first aerobic tank uses perforated aeration pipes for continuous aeration, and the air volume is controlled at 25-30m 3 / h, dissolved oxygen is 1-3mg / L; sludge concentration is 35-45g / L, MLVSS / MLSS is 15-25%. The first aerobic tank is connected to the first sedimentation tank for sedimentation and reflux, and the air supply volume of the air stripping reflux is 15-25m 3 / h, the return flow rate is 100%-150%, and a hydrocyclone is installed on the return pipe to screen the sludge. The ratio of the return sludge screened by the hydrocyclone to the residual sludge is 2-4:6-8;

[0085] The gelatin wastewater after biological decalcification is biochemically treated and first enters the second anaerobic tank and the second anoxic tank, and then enters the second aerobic tank. The pH of the second aerobic tank is controlled at 7-8, and the aerobic tank uses microporous aeration tubes for continuous aeration, and the air volume of the blower is 22-28m 3 / h, dissolved oxygen is 2-4mg / L; the sludge concentration of the second aerobic tank is 4-6g / L, MLVSS / MLSS is 65-80%, the effluent enters the second sedimentation tank for sedimentation, and the supernatant can be discharged to the clear water tank, and the effluent of the clear water tank can be reused. The biological decalcification treatment time is shorter than the biochemical treatment time, with a ratio of 2:3 to 1:2.

[0086] Comparative Example 1

[0087] No concentrated sulfuric acid and biological decalcification treatment was performed, and other step parameters were the same as those in the embodiment.

[0088] The activated sludge from the first aerobic tank and the second aerobic tank was collected for property comparison, such as Figure 1 As shown, Figure 1 The right side of the figure shows the sludge from the first aerobic tank, and the left side shows the sludge from the second aerobic tank. Figure 1 It can be seen that the sludge properties in the first aerobic tank of biological decalcification and the second aerobic tank of biochemical treatment are very different. Since the first aerobic tank in biological decalcification plays a role in decalcification, the sludge in the tank is white due to calcium precipitation, while the sludge in the second aerobic tank is normal yellow-brown. Therefore, the interception of calcium ions by biological decalcification ensures that the biomass of the sludge in the later stage of biochemical treatment is high and the biological activity is good.

[0089] The species in the activated sludge of the first aerobic tank, the second aerobic tank and the original aerobic tank for treating wastewater were analyzed. The Venn diagram of species composition and diversity index are shown in Figure 2. Figure 8 The community composition is shown in Fig. 9 shown.

[0090] Figure 8 The species composition in the biological decalcification first aerobic tank A1, the biochemical treatment second aerobic tank A2 (pilot system) and the activated sludge aerobic tank A3 (large system) in the middle left figure shows that the microorganisms in the biological decalcification first aerobic tank A1 and the biochemical treatment second aerobic tank A2 in the method of the present application have less overlap with the microorganisms in the ordinary activated sludge aerobic tank A3, while there are some overlapping microorganisms in the A1 and A2 tanks. The microbial species enriched by the method of the present application are significantly different from those enriched by the ordinary activated sludge method.

[0091] The biodiversity index of the three Figure 8 As can be seen from the middle right figure, the microbial diversity index in the second aerobic tank A2 of the biochemical treatment in this method is the highest, and its microbial population is richer than that in the ordinary activated sludge aerobic tank. The first aerobic tank A1 has a lower microbial diversity than A2 because it serves as a decalcification tank.

[0092] Fig. 9 It can also be clearly seen from the community composition diagram that the microbial community composition of the second aerobic pool A2 in the biochemical treatment is richer and more diverse. At the same time, there are obvious differences in the microbial community composition of A1, A2, and A3, and the microbial systems are very different. The main microorganisms in the first aerobic pool A1 for biological decalcification are thiothiabacteria, which can oxidize H2S as an energy source, reduce the toxicity of H2S to subsequent biochemical reactions, and have a certain detoxification effect. The second aerobic pool A2 for biochemical treatment is mainly dominated by denitrifying bacteria, such as soil monocytogenes, etc., which are enriched in a large number of denitrifying bacteria and have denitrification and denitrification functions. At the same time, it contains the family of saprophytic spirochetes that can metabolize carbon sources. Due to the enrichment of a large number of dominant bacterial species, the effluent effect is good. In the ordinary activated sludge aerobic pool A3, the main microorganisms are Prevotella, whose function is to decompose proteins and carbohydrates, as well as some lactobacilli, faecal enterococci, etc., and no denitrification dominant bacterial species are formed.

[0093] The microbial results show that the microbial population enriched by the present application method is richer, more comprehensive in function, and has better treatment effect than the activated sludge in the ordinary aerobic pool. At the same time, it has a greater advantage in denitrification than the ordinary aerobic pool. The process flow of the present application method has extremely high treatment efficiency for gelatin wastewater, good treatment effect, low cost, and obvious advantages in denitrification. It can not only solve the problem of gelatin wastewater discharge, but also increase the front-end gelatin production capacity. It is an efficient and low-energy gelatin wastewater solution.

[0094] The COD, ammonia nitrogen and total nitrogen contents in the wastewater after each treatment process of the embodiment were monitored in real time. The results are as follows: Figure 2-4 As shown, Figure 2 This is the change diagram of COD content in wastewater; Figure 3 It is the change diagram of ammonia nitrogen content; Figure 4 This is a graph showing the changes in total nitrogen content.

[0095] from Figure 2 It can be seen that the primary hydrolysis and acidification has little effect on the COD content, the secondary hydrolysis and acidification can reduce the COD content by 10% to 25%, and after biological decalcification, the COD content drops significantly, and the organic matter removal rate of the biological decalcification process can reach 70%-90%. The total COD removal rate is above 90%.

[0096] from Figure 3From the ammonia nitrogen content change chart, we can see that the ammonia nitrogen content in the influent is low, but after the primary hydrolysis and acidification, the ammonia nitrogen content increases sharply, and the conversion of organic nitrogen into ammonia nitrogen can reach 50% to 80%; after the secondary hydrolysis and acidification, the ammonia nitrogen content increases further, and the conversion of organic nitrogen into ammonia nitrogen is 20% to 50%. After biological decalcification treatment, the ammonia nitrogen content decreases, indicating that biological decalcification can remove part of the nitrogen, and the nitrogen removal rate is 10-30%. Obviously, after biochemical treatment, the ammonia nitrogen content is basically reduced to 0, and the ammonia nitrogen removal rate is close to 98%. From Figure 3 The changes in the total nitrogen in the influent and effluent during the biochemical treatment process also show that after the treatment method of the present application is stabilized, the removal rate of total nitrogen can reach 95%, the ammonia nitrogen content in the wastewater is <5mg / L, and the total nitrogen content is less than 10mg / L. This is because biological decalcification is mainly used for calcium removal and has little effect on nitrogen removal. After a period of acclimatization and enrichment of nitrifying and denitrifying bacteria, it is helpful for biochemical treatment.

[0097] The treatment method of the present application is described, and it can effectively treat gelatin wastewater.

[0098] Comparative Example 1 does not carry out concentrated sulfuric acid decalcification and biological decalcification treatment on the wastewater. Figure 5 As shown in the figure, the COD removal rate of the subsequent ordinary aerobic pool without biological decalcification treatment is more than 90%, which is not much different from the subsequent biological treatment effluent with biological decalcification treatment. Figure 6 and Figure 7 It can be seen that the removal rate of ammonia nitrogen and total nitrogen in the subsequent ordinary aerobic pool of Comparative Example 1 without biological decalcification treatment is only 0%-25%, which is quite different from the subsequent biological treatment effluent after biological decalcification treatment. Its denitrification effect is poor, and both nitrification and denitrification are relatively weak.

[0099] In summary, the present application adopts a complete set of processes consisting of regulation, two-stage hydrolysis acidification, and a secondary aerobic stage, which can efficiently convert organic nitrogen in gelatin wastewater, reduce the impact of calcium ions on microorganisms, effectively reduce the content of organic pollutants and ammonia nitrogen in the wastewater, and have a good sewage treatment effect; recycle the remaining sludge for resource treatment, reduce treatment costs, and recycle resources.

[0100] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0101] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0102] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A high-efficiency and low-energy consumption treatment method for gelatin wastewater, characterized in that: The following steps are involved: The wastewater is sequentially subjected to primary hydrolysis and acidification, secondary hydrolysis and acidification, biological decalcification, and biochemical treatment; Among them, biological decalcification and biochemical treatment are A 2 O process, comprising using an anaerobic tank, an anoxic tank and an aerobic tank containing activated sludge to treat the wastewater.

2. The high-efficiency and low-energy consumption treatment method for gelatin wastewater according to claim 1, characterized in that: Before the primary hydrolysis and acidification, concentrated sulfuric acid is added to the wastewater and stirred to adjust the pH of the wastewater; then the wastewater is allowed to settle.

3. The high-efficiency and low-energy consumption treatment method for gelatin wastewater according to claim 1, characterized in that: The conditions of the primary hydrolysis and acidification are: acidification in an expanded sludge bed at a pH of 9-10 for 5-7 hours; dissolved oxygen is controlled at DO<0.5 mg / L; the volumetric load of the primary hydrolysis and acidification is 5.5-7 kg COD / (m 3 d); The conditions for secondary hydrolysis and acidification are: acidification in the expanded sludge bed for 9 to 13 hours; dissolved oxygen is controlled at DO < 0.5 mg / L, and the volumetric load of the secondary hydrolysis and acidification is 2 to 3 kg COD / (m 3 ·d).

4. The high-efficiency and low-energy consumption treatment method for gelatin wastewater according to claim 1, characterized in that: In the biological decalcification, the dissolved oxygen in the anaerobic tank is less than 0.2 mg / L, and the dissolved oxygen in the anoxic tank is less than 0.5 mg / L; The pH of the aerobic pool is 8-9; the aeration air volume of the aerobic pool is controlled at 25-30m 3 / h, dissolved oxygen is 1-3mg / L; aerobic pool sludge concentration is 35-45g / L, MLVSS / MLSS is 15-25%.

5. The high-efficiency and low-energy consumption treatment method for gelatin wastewater according to claim 1, characterized in that: The biological decalcification process also includes sedimentation, where the wastewater treated in the aerobic tank enters the sedimentation tank for sedimentation; The gas supply volume of the sedimentation tank is 15-25m 3 / h, the reflux rate is 100%-150%; the mass ratio of sludge reflux rate to residual sludge is 2-4:6-8.

6. The high-efficiency and low-energy consumption treatment method for gelatin wastewater according to claim 1, characterized in that: In the biochemical treatment, the dissolved oxygen in the anaerobic tank is less than 0.2 mg / L, and the dissolved oxygen in the anoxic tank is less than 0.5 mg / L; The pH of the aerobic pool is 7-8; the aeration air volume of the aerobic pool is 22-28m 3 / h, dissolved oxygen is 2-4mg / L; aerobic pool sludge concentration is 4-6g / L, MLVSS / MLSS is 65-80%.

7. The high-efficiency and low-energy consumption treatment method for gelatin wastewater according to claim 1, characterized in that: The time ratio of biological decalcification treatment and biochemical treatment is 2:3 to 1:

2.

8. The high-efficiency and low-energy consumption treatment method for gelatin wastewater according to claim 1, characterized in that: After the wastewater is biochemically treated and precipitated, the supernatant is the qualified wastewater after treatment.

9. A high-efficiency and low-energy consumption treatment system for gelatin wastewater, characterized in that: It includes a primary hydrolysis acidification tank, a secondary hydrolysis acidification tank, a biological decalcification unit, and a biochemical treatment unit connected in sequence; The biological decalcification unit comprises a first anaerobic tank, a first anoxic tank, a first aerobic tank and a first sedimentation tank which are connected in sequence; The biochemical treatment unit comprises a second anaerobic tank, a second anoxic tank and a second aerobic tank which are connected in sequence.

10. A high-efficiency and low-energy consumption treatment system for gelatin wastewater according to claim 9, characterized in that: A regulating tank is also provided in front of the primary hydrolysis tank, and the regulating tank includes a stirring zone and a static zone which are connected in sequence; the static zone is connected to the primary hydrolysis acidification tank; The biochemical treatment unit also includes a second sedimentation tank and a clean water tank which are connected in sequence, and the second aerobic tank of the biochemical treatment unit is connected to the second sedimentation tank; The first aerobic tank and the second aerobic tank are respectively provided with an aeration device; The first sedimentation tank and the second sedimentation tank are respectively provided with a gas stripping reflux device.

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