CN110040849B - Biochemical treatment method of oil refining wastewater - Google Patents

Biochemical treatment method of oil refining wastewater Download PDF

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CN110040849B
CN110040849B CN201910202210.1A CN201910202210A CN110040849B CN 110040849 B CN110040849 B CN 110040849B CN 201910202210 A CN201910202210 A CN 201910202210A CN 110040849 B CN110040849 B CN 110040849B
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CN110040849A (en
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王庆宏
陈春茂
梁家豪
明婕
王鑫
詹亚力
郭绍辉
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China University of Petroleum Beijing
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/30—Aerobic and anaerobic processes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/16—Nitrogen compounds, e.g. ammonia
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
    • C02F2103/36—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds
    • C02F2103/365—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds from petrochemical industry (e.g. refineries)

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Abstract

The invention provides a biochemical treatment method of oil refining wastewater, which utilizes a UASB anaerobic reactor and an SBR aerobic reactor which are arranged in series, wherein anaerobic granular sludge and aerobic granular sludge which are cultured and domesticated are respectively arranged in the UASB anaerobic reactor and the SBR aerobic reactor, and the treatment method comprises the following steps: and (2) operating the UASB and the SBR, introducing the oil refining wastewater to be treated into the UASB to perform anaerobic treatment, and introducing the wastewater subjected to the anaerobic treatment into the SBR to perform aerobic treatment after discharging, wherein the oil content of the oil refining wastewater to be treated is not higher than 300mg/L, and the COD of the wastewater entering the SBR is 200-600mg/L, pH and is 6.5-7.5. The treatment method can not only avoid the loss of the sludge, save the floor area of the reactor and reduce the capital investment cost, but also ensure that the indexes of the treated wastewater can meet the relevant industrial standards.

Description

Biochemical treatment method of oil refining wastewater
Technical Field
The invention relates to a wastewater treatment method, in particular to a biochemical treatment method of oil refining wastewater.
Background
The oil refining production process is complex, the flow is long, and the material components are different, so that the oil refining wastewater has large water quality fluctuation, a plurality of pollutant types and complex composition, not only contains substances such as petroleum, ammonia nitrogen, sulfide and the like, but also contains a large amount of soluble organic matters including phenols, organic acids, aldehyde ketones, esters, alkanes, polycyclic compounds, organic amines, alcohols, nitriles, heterocyclic compounds and the like. In recent years, along with the continuous increase of the proportion of processing heavy crude oil in the petroleum refining process, the biotoxicity, the treatment load and the biodegradation difficulty of oil refining wastewater are continuously improved, the water quality of the wastewater is continuously deteriorated, and the organic matter load is higher and higher. In 2015, 7 and 1, the national standard for oil refining wastewater discharge (discharge standard for pollutants for petrochemical industry) (GB31571-2015) is issued by the environmental protection department, the standard improves the pollutant discharge limit of oil refining wastewater, and compared with the original discharge standard (comprehensive discharge standard for sewage) (GB8978-1996), the main macroscopic pollutant index COD is reduced by 30%, the ammonia nitrogen is reduced by nearly 50%, and the total nitrogen is upgraded to 40mg/L from 'no requirement'. Therefore, the water quality deterioration problem of the oil refining wastewater and the stricter pollutant emission standard bring double pressure to the treatment of the oil refining wastewater.
The biochemical treatment process mainly utilizes the advantages of rapid growth and propagation of microorganisms, thorough decomposition of organic matters, no secondary pollution and the like to deeply remove soluble organic matters and nitrogen-containing compounds, and the biochemical treatment is the core of the oil refining wastewater treatment process. CN201610535428 discloses a biochemical treatment process of oily sewage, which adopts a treatment unit of an anaerobic tank, a middle sedimentation tank, an aerobic tank and a secondary sedimentation tank to complete the removal and denitrification of organic matters, a filler is additionally arranged in the anaerobic tank to improve biomass and form a biological membrane, the removal of the organic matters and the improvement of the biodegradability of water quality are enhanced, and effluent treated by the process can reach the standard and be discharged. CN 102718359B reports an oil refining wastewater biochemical treatment system based on MBR, and the system is composed of an aerobic aeration tank, an intermediate sedimentation tank, an anoxic tank and a membrane bioreactor, wherein microorganisms in the aeration tank adsorb a large amount of oil substances, the anoxic tank converts refractory organic matters into easily degradable substances, and the MBR can ensure the quality of effluent water to achieve the purpose of advanced treatment and recycling. CN 101870544B discloses a treatment method of petroleum refining wastewater, wherein a biochemical unit of the method adopts a two-stage anaerobic and aerobic treatment system. After the first-stage hydrolysis acidification treatment, the B/C reaches more than 0.35, and after the second-stage biochemical treatment, the COD of the effluent of the secondary sedimentation tank is reduced to be less than 60 mg/L.
The biochemical treatment methods of the oil refining wastewater reported above are all technologies for treating oily wastewater by using activated sludge. Aiming at the defect that activated sludge is easy to lose in the treatment process, the activated sludge needs to be refluxed by using equipment such as a middle sedimentation tank, a secondary sedimentation tank and the like in the processes in the reports, so that the loss of the activated sludge is avoided, and therefore, the occupied area of the equipment such as the middle sedimentation tank, the secondary sedimentation tank and the like is increased, and the capital investment and the operation cost are also increased.
At present, the granular sludge technology derived from the traditional activated sludge method has good sedimentation performance, is not easy to lose and is convenient for solid-liquid separation; the biomass is large, and the processing load is high; compact structure, can resist the impact of toxic and harmful substances and the like, and is widely concerned by the domestic and foreign sewage treatment fields. However, the granular sludge has poor universality and harsh working starting conditions, and the granular sludge can only exert the advantages of the granular sludge when the granular sludge can grow and stably exist in the wastewater to be treated and can cultivate targeted degradation flora in the wastewater to be treated. At present, the method is mainly applied to the treatment of municipal wastewater, food processing wastewater and the like, and the treatment effect can basically meet the requirements because the pollutant composition of the wastewater is relatively single and the water quality biodegradability is better.
However, how to enable the granular sludge to grow, stably exist and culture a targeted pollutant degradation flora in the oil refining wastewater with complex pollutant composition and poor biodegradability is still a technical problem to be solved in the field.
Disclosure of Invention
The invention provides a biochemical treatment method of oil refining wastewater, which can avoid the loss of sludge, save the floor area of a reactor, reduce the capital investment cost, and ensure that the index of the treated wastewater can reach the discharge standard.
The invention provides a biochemical treatment method of oil refining wastewater, which utilizes a UASB anaerobic reactor and an SBR aerobic reactor which are arranged in series, wherein anaerobic granular sludge and aerobic granular sludge which are cultured and domesticated are respectively arranged in the UASB anaerobic reactor and the SBR aerobic reactor, and the treatment method comprises the following steps:
operating UASB and SBR, introducing the oil refining wastewater to be treated into the UASB to perform anaerobic treatment, introducing the wastewater after the anaerobic treatment into the SBR to perform aerobic treatment after the wastewater is discharged, and discharging the wastewater, wherein the oil content of the oil refining wastewater to be treated is not higher than 300mg/L, and the COD of the wastewater entering the SBR is 200-600mg/L, pH and is 6.5-7.5;
the anaerobic granular sludge is prepared by culturing and domesticating the following processes:
adding hydrolytic acidification sludge into UASB, introducing diluted oil refining wastewater to be treated as inlet water, starting up UASB, adding co-culture substrate, maintaining the UASB operation process to increase the COD of the inlet water and reduce the carbon source content of the co-culture substrate until the volume content of methane in the UASB is greater than 55% and the removal rate of COD is greater than 70%, and completing culture and domestication of anaerobic granular sludge;
the aerobic granular sludge is prepared by culturing and domesticating the following processes:
adding aerobic activated sludge into SBR, introducing diluted oil refining wastewater to be treated as inlet water, starting the SBR, adding a co-culture substrate, and maintaining the sedimentation time and the carbon source content of the co-culture substrate in the operation process of the SBR until the sludge volume index SVI of the sludge in the SBR is less than 40mL/g and the COD removal rate is more than 90%, thereby completing the culture and domestication of the aerobic granular sludge; wherein, the COD of SBR inlet water is less than the initial COD of UASB inlet water.
Specifically, before the oil refining wastewater to be treated is subjected to biochemical treatment, anaerobic granular sludge with a degradation effect on the oil refining wastewater to be treated needs to be cultured and domesticated in a UASB anaerobic reactor, aerobic granular sludge with a degradation effect on the oil refining wastewater to be treated needs to be cultured and domesticated in an SBR aerobic reactor, then the oil refining wastewater to be treated enters the UASB, the oil refining wastewater to be treated is discharged after being subjected to anaerobic treatment by the anaerobic granular sludge in the UASB, then the discharged wastewater is introduced into the SBR after being regulated so that COD is 200-containing-600 mg/L, pH is 6.5-7.5, the wastewater is further subjected to aerobic treatment by the aerobic granular sludge in the wastewater, and the wastewater discharged from the SBR completes the whole biochemical treatment process.
According to the method of the present invention, the oil content of the oil refining wastewater to be treated entering the treatment system should not be higher than 300mg/L, and if the oil content of the oil refining wastewater discharged from the refinery does not satisfy the above-mentioned limitation, the oil refining wastewater discharged from the refinery can be pretreated, such as oil removal and flotation treatment.
According to the invention, in the process of carrying out biochemical treatment on the oil refining wastewater to be treated, the anaerobic granular sludge in the UASB can carry out hydrolytic acidification decomposition on dissolved oil and organic pollutants in the oil refining wastewater to be treated, so that the dissolved oil and the organic pollutants are converted into organic matters with low molecular weight and simple molecular structure, such as short-chain fatty acids, saccharides, alcohols and the like, and simultaneously part of the organic matters can be converted into methane gas to be discharged, while the aerobic granular sludge in the SBR can further reduce the easily degradable organic matters into carbon dioxide and water, and convert ammonia nitrogen into nitrate to be further converted into nitrogen gas to be discharged. Therefore, the wastewater treated by the method can reach the discharge standard of the industry.
The anaerobic granular sludge and the aerobic granular sludge used in the invention are cultured and domesticated, and can perform targeted degradation on the oil refining wastewater to be treated by matching with UASB and SBR treatment processes, and the culture and domestication processes of the anaerobic granular sludge and the aerobic granular sludge are introduced below.
The culture acclimation of the anaerobic granular sludge needs to be carried out in UASB. Firstly, adding hydrolytic acidification sludge of refinery wastewater refineries to be treated into UASB, introducing diluted products of the refinery wastewater to be treated into the UASB as inlet water, simultaneously adding co-culture matrix into the UASB to provide nutrient environment for sludge growth (the co-culture matrix can also be mixed with the inlet water and enter the UASB together), and then operating the UASB with certain hydraulic retention time. The dilution product of the oil refining wastewater to be treated means that the oil refining wastewater to be treated with higher oil content is diluted firstly (tap water can be used) and then is used for acclimatization of sludge, so that the oil content and COD of the influent water of the UASB are lower than the oil content and COD of the oil refining wastewater to be treated.
In the process of operating the UASB, the COD of the inlet water and the content of the carbon source in the added co-culture substrate are continuously adjusted to acclimatize the hydrolyzed and acidified sludge into anaerobic granular sludge with the capacity of degrading the refinery wastewater to be treated, and the monitored performance parameters of the UASB outlet effluent (gas and liquid) are used as the standard for finishing the acclimation. Specifically, in the operation process of the UASB, the COD of the inlet water is continuously increased, the content of the carbon source in the added co-culture substrate is reduced, when the volume content of methane in the gas escaping from the UASB outlet is monitored to be more than 55%, and the removal rate of the COD in the wastewater discharged from the UASB outlet is monitored to be more than 70%, the culture and domestication of the anaerobic granular sludge are completed, namely, the hydrolytic acidification sludge in the UASB is changed into the anaerobic granular sludge with the degradation effect on the oil refining wastewater to be treated.
Because the UASB is operated in a process of pointing to the UASB to continuously feed water and continuously drain water, the increase of the COD of the inlet water refers to the COD of the inlet water after the intake water is increased by taking the COD value of the inlet water during the initial operation of the UASB as a starting point, and generally, the increased COD of the inlet water does not exceed the COD of the refinery wastewater to be treated; the above-mentioned reduction of the carbon source content of the co-culture substrate means that the carbon source content added after the reduction using the carbon source content value at the time of the initial operation of UASB as a starting point is generally 0 at the minimum, that is, no carbon source is added to the UASB. That is, the present invention acclimatizes the hydrolysis-acidification sludge into anaerobic granular sludge by using the increase in the COD value of wastewater and the decrease in the amount of carbon source in the UASB as acclimatization conditions.
In the acclimation process, the COD of the inlet water can be increased in any variable quantity stage; the carbon source content may be gradually decreased in an arbitrary amount. The specific operation process can be determined according to the pollution degree of the wastewater, and it is pointed out that the more times of adjustment, the closer the final influent COD is to the COD of the refinery wastewater to be treated, the less carbon source is added into the UASB, and the better the degradation capability of the anaerobic granular sludge obtained by acclimatization is. In addition, the improvement of the influent COD and the reduction of the carbon source content can be synchronously carried out or can be carried out step by step, and the domestication effect carried out step by step is superior to that carried out synchronously.
Similarly, culture acclimation of aerobic granular sludge needs to be performed in SBR. Firstly, adding aerobic sludge (aeration tank activated sludge or secondary sedimentation tank excess sludge) of an oil refining wastewater refinery to be treated into SBR, introducing a diluted product of the oil refining wastewater to be treated into the SBR as inlet water for a certain water inlet time, simultaneously adding a co-culture substrate into the SBR to provide a nutrient environment for sludge growth (the co-culture substrate can also be mixed with the inlet water and enter the SBR together), and then operating the SBR for a certain sedimentation time, aeration time, drainage time and idle time. Similarly, the dilution product of the refinery waste water to be treated means that the refinery waste water to be treated having a higher oil content can be diluted (tap water can be used) and then used for acclimatization of sludge, so that the oil content and COD of the SBR feed water are lower than those of the refinery waste water to be treated, and in the present invention, the COD and oil content of the SBR feed water are lower than those of the UASB feed water.
In the process of operating the SBR, the aerobic sludge is acclimated to be aerobic granular sludge with the degradation capability of the refinery wastewater to be treated by continuously reducing the sedimentation time of each operation of the SBR and reducing the content of the carbon source added into the co-culture substrate, and the monitored performance parameter of the effluent of the SBR is used as the standard for finishing the acclimation. Specifically, in the operation process of the SBR, the sedimentation time of each SBR operation is continuously reduced so as to retain sludge with good sedimentation performance through the hydraulic screening effect, the carbon source content of the co-culture substrate added into the SBR is continuously reduced, and when the COD removal rate detected in the wastewater discharged from the outlet of the SBR is more than 90%, the culture domestication of aerobic granular sludge is completed, namely the activated sludge of the aeration tank in the SBR is the aerobic granular sludge with the degradation treatment effect on the oil refining wastewater to be treated.
Because the operation of the SBR is the process of sequentially carrying out water inlet, aeration, sedimentation, drainage and idling, the sedimentation time reduction refers to the sedimentation time of the SBR after the sedimentation time of the SBR in the initial operation of the SBR is used as a starting point, and generally, the sedimentation time is adjusted until the sludge volume index SVI of the sludge in the SBR is less than 40 mL/g; the carbon source content of the co-culture substrate is reduced by using the carbon source content value of the SBR during initial operation as a starting point, and the carbon source content after reduction is generally 0 at the minimum, namely, the carbon source is not added into the SBR. That is, the present invention acclimatizes aerobic sludge to aerobic granular sludge by using the settling time of SBR operation and the decrease in carbon source amount as acclimatization conditions.
In the acclimation process, the settling time can be reduced in any variable quantity stage; the carbon source content may be gradually decreased in an arbitrary amount. The specific operation process can be determined according to the pollution degree of the wastewater, and it is noted that the more times of adjustment, the closer the SVI of the sludge in the SBR is to 40mL/g, and the less carbon source is added into the SBR, the better the degradation capability of the aerobic granular sludge obtained by acclimatization is. In addition, the sedimentation time reduction and the carbon source content reduction can be carried out synchronously or step by step, and the domestication effect carried out step by step is better than that carried out synchronously.
It should be noted that, because the operating parameters of the UASB corresponding to the time when the cultivation and acclimation of the anaerobic granular sludge is completed can ensure that the anaerobic granular sludge normally operates, and the operating parameters of the SBR corresponding to the time when the cultivation and acclimation of the aerobic granular sludge is completed can ensure that the aerobic granular sludge normally operates, when the oil refining wastewater to be treated is biochemically treated, the operating parameters of the UASB can adopt the operating parameters of the UASB corresponding to the time when the cultivation and acclimation of the anaerobic granular sludge is completed, and the operating parameters of the SBR can adopt the operating parameters of the SBR corresponding to the time when the cultivation and acclimation of the aerobic granular sludge is completed.
When the anaerobic granular sludge and the aerobic granular sludge are cultured and domesticated, the oil refining wastewater to be treated is directly domesticated, so that the degradation capability of the anaerobic granular sludge and the aerobic granular sludge on the oil refining wastewater to be treated can be enhanced, the biochemical treatment effect can be greatly improved when the UASB and the SBR are finally connected in series to carry out biochemical treatment on the oil refining wastewater to be treated, and the finally treated wastewater can reach the discharge standard in the industry.
According to the invention, the UASB anaerobic reactor and the SBR aerobic reactor are combined to carry out biochemical treatment on the oil refining wastewater, and the anaerobic granular sludge is arranged in the UASB and the aerobic granular sludge is arranged in the SBR, so that the loss of the sludge is effectively avoided, the effective utilization rate of the sludge is improved, the arrangement of the centering sedimentation tank and the secondary sedimentation tank can be omitted, and the capital construction investment and the operation cost of the oil refining wastewater are effectively saved.
Further, in order to improve the culture acclimation efficiency of the anaerobic granular sludge, the composition of a system introduced by UASB and SBR can be regulated and controlled in the culture acclimation process.
In one embodiment, for the culture acclimation of the anaerobic granular sludge, the alkalinity of the inlet water is 2000-3000mg/L, the oil content is not higher than 200mg/L, COD and is 500-600mg/L, and the mass ratio of the COD of the inlet water to the N, P element in the co-culture matrix is (350-500): 5: 1; and/or the presence of a gas in the gas,
for the culture acclimation of the aerobic granular sludge, the oil content of the inlet water is not higher than 100mg/L, COD and is 200-500mg/L, and the mass ratio of the COD of the inlet water to the N, P element in the co-culture medium is 100: (3-5): 1.
during specific operation, oil removal-air flotation treatment can be performed on the oil refining wastewater to be treated to remove suspended matters, emulsified oil and dispersed oil in the oil refining wastewater, and then the oil refining wastewater is diluted to a target oil content and a target COD, so that influent water meeting the oil content and the COD is obtained; the mass ratio of COD, N and P can be obtained by controlling the types and contents of nutrients in the co-culture medium introduced into UASB and SBR. Wherein, N element can be realized by ammonium ion, and P element can be realized by phosphate radical and the like.
Furthermore, the volume of the hydrolytic acidification sludge added to the UASB and the volume of the aerobic sludge added to the SBR should be more than 20% of the effective capacity of the UASB and the SBR, respectively, for example, in a specific embodiment, the volume of the hydrolytic acidification sludge is 25-33% of the effective capacity of the UASB and the volume of the aerobic sludge is 50-60% of the effective capacity of the SBR.
Further, since the co-culture substrate is used to provide nutrients to the microorganisms to promote their growth, the co-culture substrate of the present invention includes a number of nutrient elements therein.
Wherein, the Co-culture medium of UASB contains nutrient elements including Fe, Zn, Co, Mn, Ni, B, Cu, K, Na, N, Mo, Cl, S, P;
the culture medium of SBR contains nutrient elements which comprise Fe, Zn, Co, Al, I, Mg, Ca, Mn, Ni, B, Cu, K, Na, N, Mo, Cl, S and P.
In one embodiment, theThe nutrient elements may be added to the co-cultivation matrix in the form of a salt or the like, e.g. the co-cultivation matrix in a UASB for cultivating acclimated anaerobic granular sludge may comprise FeCl2、CoCl2、EDTA、MnSO4、ZnSO4、NiCl2、(NH4)6Mo7O24、H2BO3、CuCl2And NH4Cl、KH2PO4、NaHCO3Wherein, NaHCO3For regulating alkalinity, NH, of feed water4Cl and KH2PO4Used for adjusting the quality of the N element and the P element; preferably, FeCl2、CoCl2、EDTA、MnSO4、ZnSO4、NiCl2、(NH4)6Mo7O24、H2BO3、CuCl2The concentration in the inlet water is 1275 mug/L, 1091 mug/L, 994/L, 888 mug/L, 60 mug/L, 32 mug/L, 47 mug/L, 49 mug/L and 19 mug/L respectively;
the co-culture medium in the SBR for culturing the acclimatized aerobic granular sludge may include H3BO3、ZnCl2、CuCl2、MnSO4、(NH4)6Mo7O24、AlCl3、CoCl2、NiCl2、KI、MgCl2、FeCl2、CaCl2And NH4Cl、KH2PO4Wherein NH4Cl and KH2PO4Used for adjusting the quality of the N element and the P element; preferably, H3BO3、ZnCl2、CuCl2、MnSO4、(NH4)6Mo7O24、AlCl3、CoCl2、NiCl2、KI、MgCl2、FeCl2、CaCl2The concentrations in the feed water were 50. mu.g/L, 30. mu.g/L, 45. mu.g/L, 47. mu.g/L, 50. mu.g/L, 27. mu.g/L, 50. mu.g/L, 30. mu.g/L, 97. mu.g/L, 9. mu.g/L, 23. mu.g/L, respectively.
In addition, the carbon source in the co-culture substrate is selected from organic carbon sources, and further, the carbon source in the co-culture substrate includes sugars such as glucose, maltose, lactose, and the like, and particularly, when the carbon source content is calculated, the concentration of glucose in the feed water may be calculated.
In the invention, when the acclimatized anaerobic granular sludge is cultured, the carbon source in the co-culture substrate can be preferably glucose, and the initial concentration of the glucose in the influent water can be 900-1100mg/L at the beginning of UASB operation; when the acclimatized aerobic granular sludge is cultured, the carbon source in the co-culture substrate can be preferably glucose, and the initial concentration of glucose in the influent water can be 500-700mg/L at the beginning of the SBR operation.
The specific process flow of culturing and domesticating the anaerobic granular sludge and the aerobic granular sludge can be regulated and controlled according to the properties of the usable sludge and wastewater, and the UASB can be used as the granular sludge for treating the oil refining wastewater as long as the UASB has the methane volume content of more than 55 percent, the COD removal rate of more than 70 percent and the SBR has the COD removal rate of more than 90 percent.
Illustratively, on the basis of the above embodiment, the culture acclimation of the anaerobic granular sludge comprises the following steps:
1) adding hydrolytic acidification sludge and co-culture matrix into UASB, introducing diluted oil refining wastewater to be treated as inlet water, and operating until the gas production rate in UASB is greater than 0.5m by using hydraulic retention time T3/m3D, volume content of methane>60% and COD removal rate>80％；
2) Increasing COD of the inlet water in a staged manner and operating the UASB for a hydraulic retention time T until the COD of the inlet water is basically the same as the COD of the refinery wastewater to be treated, the volume content of methane in the UASB is more than 55%, and the removal rate of the COD is more than 70%;
3) stepwise reducing the carbon source content and operating the UASB with stepwise reduced hydraulic retention time until the carbon source content is zero and the hydraulic retention time is TNVolume content of methane in UASB>55% removal rate of COD>70 percent, completing the culture and domestication of the anaerobic granular sludge;
wherein, TN＜T。
In step 1), introducing inlet water and a co-culture substrate into the UASB containing the hydrolytic acidification sludge according to the limited parameters, operating the UASB for a hydraulic retention time T, and monitoringThe gas production to UASB is more than 0.5m3/m3D (i.e. 0.5 cubic gas produced per cubic UASB per day), methane volume content>60% and COD removal rate>At 80%, it was confirmed that anaerobic microorganisms had grown to an effective amount in UASB. In the step 1), the hydraulic retention time T is 28-30h, and the operation period is 30-50 days.
After step 1) is completed, the staged increase of the influent COD can be performed, and anaerobic microorganisms growing in the process gradually increase the anaerobic degradation capability by gradually increasing the content of COD in the system. Specifically, the COD of the last influent water can be adjusted to be substantially the same as the COD of the refinery wastewater to be treated (substantially the same means within 50mg/L of the COD of the refinery wastewater to be treated), that is, the COD of the influent water after each adjustment is greater than the COD of the influent water before the adjustment, and the COD of the influent water after the Q-th adjustment is substantially the same as the COD of the refinery wastewater to be treated. In order to ensure the smooth operation of UASB and the effectiveness of anaerobic granular sludge, it is beneficial to make the COD increase amount of each influent water be approximately the same and after each adjustment, when the volume content of methane in UASB is greater than 55%, the COD removal rate is greater than 70%, and after a certain period of smooth operation according to the parameters, for example, no less than 5 days, the next adjustment is performed.
Hereinafter, the regulation process of the intake water COD will be described with Q ═ 5 as an example. For example, the initial COD of the influent water in the step 1) is 500mg/L and the COD of the refinery wastewater to be treated is 2980mg/L, and in the step 2), after the first adjustment is performed so that the COD of the influent water introduced into the UASB is 1000mg/L and the UASB is operated for a period of time with the hydraulic retention time T, when the volume content of methane in the UASB is greater than 55%, the removal rate of COD is greater than 70% and the UASB is stably operated for not less than 5 days, the second adjustment is performed; the second adjustment makes the influent COD of the UASB introduced be 1500mg/L and operates for a period of time with the hydraulic retention time T, and when the volume content of methane in the UASB is more than 55%, the COD removal rate is more than 70% and the stable operation is not less than 5 days, the third adjustment is carried out; after the third adjustment leads the COD of the inlet water introduced into the UASB to be 2000mg/L and the UASB is operated for a period of time by the hydraulic retention time T, when the volume content of methane in the UASB is more than 55 percent, the COD removal rate is more than 70 percent and the UASB is stably operated for not less than 5 days, the fourth adjustment is carried out; the fourth adjustment makes the influent COD of the UASB introduced be 2500mg/L and operates for a period of time with the hydraulic retention time T, and when the volume content of methane in the UASB is more than 55%, the COD removal rate is more than 70% and the UASB stably operates for no less than 5 days, the fifth adjustment is carried out; and (3) after the fifth adjustment to ensure that the COD of the influent water introduced into the UASB is 3000mg/L (basically the same as the COD of the refinery wastewater to be treated) and the UASB is operated for a period of time with the hydraulic retention time T, when the volume content of methane in the UASB is more than 55 percent, the removal rate of the COD is more than 70 percent and the UASB is smoothly operated for no less than 5 days, the step 2) is completed.
It can be understood that only the COD of the influent water is changed in step 2) and the hydraulic retention time for UASB operation is maintained at T. After COD adjustment of water inflow each time, the volume content of methane is more than 55% and the removal rate of COD is more than 70% under the current COD parameter by enabling the UASB to run for a certain time, and then the next COD adjustment is carried out. The running time of the UASB after each adjustment can be different.
Subsequently, on the basis of step 2), the carbon source content and the hydraulic retention time are adjusted. In the process of operating the UASB, the content of the carbon source (the concentration of the carbon source in the inflow) introduced into the UASB and the hydraulic retention time are reduced in a staged manner until the carbon source is not added into the UASB any more and the hydraulic retention time is TNVolume content of methane in UASB>55% removal rate of COD>70 percent, and the step 3) is finished. Wherein, TN＜T。
When step 3) is performed, the COD of the influent water introduced into the UASB is substantially the same as the COD of the refinery wastewater to be treated (i.e., the COD of the final influent water in step 2) is maintained), only the amount of the carbon source added into the UASB and the hydraulic retention time are changed, and in order to realize the efficient acclimation of the anaerobic granular sludge, the synchronous adjustment of the amount of the carbon source and the hydraulic retention time is preferred.
Specifically, the step 3) comprises N times of anaerobic domestication treatment, wherein N is more than or equal to 5;
the frequency set of the anaerobic acclimation treatment is recorded as S ═ 1,2, …, i-1, i, …, N };
the amount of the carbon source added in the (i-1) th anaerobic acclimation treatment is larger than that added in the ith anaerobic acclimation treatment;
(i-1) th anaerobic modeHydraulic retention time T of acclimatization treatmenti-1The hydraulic retention time T is longer than the hydraulic retention time T of the ith anaerobic acclimation treatmenti；
In the Nth anaerobic acclimation treatment, the amount of the added carbon source is 0.
That is, the carbon source adding amount and the hydraulic retention time are adjusted N times in the step 3), and the carbon source adding amount and the hydraulic retention time after each adjustment are lower than the carbon source adding amount and the hydraulic retention time before the adjustment until the concentration of the carbon source in the influent water is 0 (namely, no carbon source is added) and the hydraulic retention time is TNVolume content of methane in UASB>55% removal rate of COD>70 percent, and the step 3) is finished. In order to ensure smooth operation of the UASB and the effectiveness of the anaerobic granular sludge, it is advantageous to operate the UASB so that the carbon source is reduced by substantially the same amount as the hydraulic retention time, and the volume content of methane in the UASB is adjusted after each adjustment>55% removal rate of COD>70% and run smoothly according to the parameters for a certain time, for example, not less than 5 days, and then the next adjustment is carried out.
The anaerobic acclimation treatment is also described with N being 5. After completion of step 2), for example, the initial concentration of the carbon source in the influent water is 1000mg/L and the hydraulic retention time T is 28 h. In the step 3), the first anaerobic acclimation treatment is carried out, the concentration of the carbon source added with UASB in the inlet water is 800mg/L, and the hydraulic retention time T is1Reducing the volume content to 24h, and after running for a period of time, when the volume content of methane in the UASB is higher than that of methane in the UASB>55% removal rate of COD>Performing anaerobic acclimation treatment for the second time when 70% of the total anaerobic bacteria are stably operated for not less than 5 days; in the second anaerobic acclimation treatment, the concentration of the carbon source added with UASB in the influent water is 600mg/L and the hydraulic retention time T2Reducing the volume content to 20h, and after running for a period of time, when the volume content of methane in the UASB is higher than that of methane in the UASB>55% removal rate of COD>Performing anaerobic acclimation treatment for the third time when 70% of the total bacteria and the stable operation are not less than 5 days; in the third anaerobic acclimation treatment, the concentration of the carbon source added with UASB in the inlet water is 400mg/L and the hydraulic retention time T3Reducing the reaction temperature to 16h, and after running for a period of time, when the volume content of methane in the UASB is higher than that of methane in the UASB>55% removal rate of COD>70% and stable operation for not less than 5 days, the first step is carried outPerforming anaerobic acclimation treatment for four times; in the fourth anaerobic acclimation treatment, the concentration of the carbon source added with UASB in the inlet water is 200mg/L and the hydraulic retention time T4Reducing the volume content to 12h, and after running for a period of time, when the volume content of methane in the UASB is higher than the volume content of methane in the UASB>55% removal rate of COD>Performing fifth anaerobic acclimation treatment when 70% of the total anaerobic bacteria stably run for not less than 5 days; in the fifth anaerobic acclimation treatment, the concentration of the carbon source added with UASB in the inlet water is 0mg/L (namely no carbon source is added) and the hydraulic retention time T5At 12h, after a period of operation, when the volume content of methane in the UASB is>55% removal rate of COD>70% and maintaining stable operation for not less than 5 days, and completing the step 3). Wherein, T5(TN)≤T4＜T3＜T2＜T1< T. It is noted here that when no carbon source is added, the hydraulic retention time is generally not decreased (i.e., the last hydraulic retention time is maintained), otherwise it is difficult to achieve the COD removal rate.
After the carbon source amount and the hydraulic retention time are adjusted each time, the volume content of the methane is more than 55% and the COD removal rate is more than 70% under the current carbon source amount and the hydraulic retention time by operating the UASB for a certain time, and then the next adjustment of the carbon source amount and the hydraulic retention time is carried out. The UASB operating time after each parameter adjustment can be different.
The total time of the step 2) and the step 3) is generally 60 to 90 days, and the final volume load of the UASB can reach 6 to 8gCOD/m3·d。
It should be noted that, in the above-mentioned culture and acclimation process, the COD and carbon source contents of the influent water are adjusted, but the mass ratio of COD, N element and P element and the alkalinity of the influent water need to be maintained within the limited ranges during the whole culture and acclimation process.
The average particle size of the anaerobic granular sludge cultured and domesticated by the method is 0.4-0.5nm, and the SVI is 25-35mL/g, so that the anaerobic granular sludge cultured and domesticated by the method has smaller particle size and excellent sedimentation performance. And the anaerobic granular sludge cultured and domesticated by the method can realize anaerobic degradation treatment on oil refining wastewater, so that main microorganisms possibly contained in the anaerobic granular sludge obtained by culturing and domesticating are hydrolytic acidification bacteria Caldiscericum, bacteriodes vadinHA17, Clostridium, petroleum degrading bacteria Mesotoga, Smithlla, methanogens Methanosaeta, Methanolinea, Methanobacterium and Methanospirillum.
It is emphasized that the UASB has a hydraulic retention time T when culture acclimation of the anaerobic granular sludge is completedNThat is to say, at a hydraulic retention time TNUnder the operation parameters of (3), the UASB can realize the degradation of an anaerobic sludge system which does not contain glucose and has COD which is basically the same as the COD of the oil refining wastewater to be treated, therefore, when the UASB and the SBR are connected in series and then the oil refining wastewater to be treated is subjected to biochemical treatment, the hydraulic retention time T is preferably setNAs operating parameters for the UASB.
Illustratively, on the basis of the above embodiment, the culture acclimation of the aerobic granular sludge comprises the following steps:
a) adding aerobic activated sludge and a co-culture substrate into SBR, introducing diluted oil refining wastewater to be treated as inlet water, and reducing the sedimentation time of the SBR in a staged manner until the sludge volume index of the sludge in the SBR is less than 40mL/g when the sedimentation time is S;
b) and reducing the carbon source content in a staged manner, and operating the SBR within the settling time S until the carbon source content is zero and the COD removal rate in the SBR is more than 90 percent, thereby completing the culture and domestication of the aerobic granular sludge.
In the step a), after the aerobic activated sludge is added into the SBR, the mixture of the inlet water and the co-culture substrate is introduced into the SBR according to the limited parameters for a certain time, then aeration, sedimentation, drainage and idling are respectively carried out according to a certain time, and the flow is taken as a cycle period to execute the operation of the SBR each time. In the process of each operation of SBR, the water inlet time, the aeration time, the water discharge time and the limiting time are kept unchanged, and only the settling time is reduced in sequence, namely the settling time of the SBR operation at this time is lower than the settling time of the SBR operation at the last time. The sedimentation link of the SBR is that the sludge with good sedimentation performance is gathered through the hydraulic screening effect, so along with the repeated operation of the SBR and the staged reduction of the sedimentation time, the activated sludge with poor sedimentation performance in the SBR can be gradually discharged out of the SBR along with the drainage link, when the SVI in the SBR is less than 40mL/g, the reduction of the sedimentation time of the SBR can be stopped, and the current sedimentation time S is taken as the sedimentation time of the subsequent operation of the SBR.
When step a) is completed, the amount of carbon source introduced into the SBR is adjusted. Specifically, in the water inlet link of the SBR, the amount of the carbon source added into the SBR is reduced in a staged manner, namely the amount of the carbon source added during the current SBR running is lower than the amount of the carbon source added during the last running until the COD removal rate of the SBR is more than 90% when the carbon source is not added into the SBR, and the step b) is completed.
In step b) it is emphasized that only the carbon content needs to be adjusted each time the SBR is run, whereas the operating parameters may remain the same as in step 1) and the settling time is S.
In a particular embodiment, step a) comprises: carrying out aerobic culture treatment for K times, wherein K is more than or equal to 3;
the set of times of aerobic culture treatment is P ═ {1,2, …, g-1, g, …, K };
sedimentation time S of the (g-1) th aerobic culture treatmentg-1The settlement time S is longer than the settlement time S of the g-th aerobic culture treatmentg；
The sedimentation time of the K-th aerobic culture treatment is S.
That is, the settling time is adjusted K times in step a), the settling time after each adjustment is lower than the settling time before the adjustment, until step a) is completed when the SVI in the SBR is less than 40mL/g, and the current settling time S is taken as the settling time when the subsequent SBR operates. It is noted that the total number of times of operation of the SBR in step a) is equal to or greater than K, i.e. the SBR may be continuously operated for a number of times under the current operating parameters until the amount of residual sludge in the SBR tends to be stable and then the next operation may be performed by adjusting the settling time.
The aerobic culture treatment is described as K.sub.3. At the beginning of SBR operation, namely the first aerobic culture treatment, the water inlet time is a, the aeration time is b, and the sedimentation time is S1C, the drainage time is c, d is the idle time, and when the mass of the residual sludge in the SBR is 80 percent of the mass of the initially added sludge, the concentration of the sludge is 6000mg/L and the SVI is less than 100mL/g, the aerobic culture treatment is carried out for the second time; in the second aerobic culture treatment, the water inlet time is a, the aeration time is b, and the sedimentation time is S2C, the drainage time is c, d is the idle time, and when the mass of the residual sludge in the SBR is 60-80% of the mass of the initially added sludge, the sludge concentration is 3000-5000mg/L and the SVI is less than 50mL/g, the third aerobic culture treatment is carried out; and c) finishing the step a) when the mass of the residual sludge in the SBR is 50-60% of the mass of the initially added sludge, the concentration of the sludge is 2500 plus 3000mg/L and the SVI is less than 40 mL/g. Wherein the water inlet time, aeration time, water discharge time and idle time are kept unchanged, and S is less than S2＜S1. The number of times of SBR operation is 1 or more per aerobic culture treatment.
Furthermore, the operation time of SBR can be about 5 hours each time, wherein the water inlet time a is 13-15min, the aeration time b is 222-270min, the water discharge time c is 13-15min, the idle time d is about 10min, and the sedimentation time S is1About 30min, S2About 15min, S about 5 min.
Of course, the aerobic culture treatment in step a) is not limited to 3 times, and may be adjusted according to the actual circumstances.
The sedimentation time is continuously reduced in the step a), so that the aerobic sludge completes the culture of the aerobic granular sludge under the action of hydraulic screening, and the sludge with excellent sedimentation performance is reserved, thereby improving the efficient degradation of the oil refining wastewater to be treated. The step a) is generally carried out for 20 to 30 days.
In addition to the above embodiment, the step b) includes: m times of aerobic domestication treatment, wherein the settling time of each time of the aerobic domestication treatment is S, and M is more than or equal to 3;
the number of times of the aerobic acclimation treatment is recorded as Q ═ 1,2, …, j-1, j, …, M };
wherein the carbon source content in the co-culture substrate in the (j-1) th aerobic acclimation treatment is greater than the carbon source content in the co-culture substrate in the j th aerobic acclimation treatment;
in the M-th aerobic acclimation treatment, the carbon source content in the co-culture substrate is 0.
That is, the carbon source addition amount is adjusted M times in step b), and the carbon source addition amount after each adjustment is lower than the carbon source addition amount before the adjustment, until the COD removal rate in SBR is >90% when the carbon source concentration in the influent water is 0 (i.e., no carbon source is added), and step b) is completed. In the step b), the settling time of the aerobic acclimation treatment for M times is S. In order to ensure the smooth operation of SBR and the effectiveness of aerobic granular sludge, it is more advantageous to operate such that the amount of carbon source reduction is the same for each adjustment, and after each adjustment, when the COD removal rate in SBR is >90% and the adjustment is performed for a certain period of time, for example, not less than 7 days, the next adjustment is performed.
The above-mentioned aerobic acclimation treatment is also described as M ═ 3. In step a), the initial concentration of the carbon source in the feed water was 600 mg/L. In the step b), performing first aerobic domestication treatment, wherein the concentration of a carbon source added into SBR in inlet water is 400mg/L, and after operation is performed by using fixed operation parameters (water inlet time is a, aeration time is b, sedimentation time is S, drainage time is c, and idle time is d), performing second aerobic domestication treatment when the COD removal rate in SBR is more than 90% and stable operation is performed for not less than 10 days according to the parameters; in the second aerobic acclimation treatment, the concentration of the carbon source added into the SBR in the inlet water is 200mg/L, after the operation is carried out according to fixed parameters, when the COD removal rate in the SBR is more than 90 percent and the stable operation is carried out for not less than 10 days according to the parameters, the third aerobic acclimation treatment is carried out; in the third aerobic acclimation treatment, the concentration of the carbon source added into the SBR in the inlet water is 0mg/L (namely no glucose is added), and after the operation is carried out according to fixed parameters, when the COD removal rate in the SBR is more than 90 percent and the stable operation is carried out according to the parameters for not less than 7 days, the step b) is completed.
After the carbon source amount is adjusted each time, the removal rate of COD under the current carbon source content is realized by operating SBR for a plurality of periods with fixed parameters, so that the next adjustment of the carbon source content is carried out. Wherein, the operation cycle number of SBR can be different after each adjustment.
It should be noted that, although the amount of the carbon source in the influent water was adjusted during the culture acclimatization, the mass ratio of COD, N element and P element was required to be maintained within a limited range throughout the culture acclimatization.
The average particle size of the aerobic granular sludge cultured and domesticated by the method is larger than 0.46mm, and the SVI is smaller than 40mL/g, so that the particle size of the aerobic granular sludge cultured and domesticated by the method is smaller and has excellent sedimentation performance. Therefore, the main microorganisms possibly contained in the aerobic granular sludge obtained by culture and domestication are Propioniciclava, Micropruina, Nakamurella, Zoogloea, defluviococcus and Propionivibrio.
It is emphasized that the settling time of SBR is S when the culture acclimation of aerobic granular sludge is completed. That is, under the operation parameter of the settling time S, the SBR can degrade the refinery wastewater containing no glucose, and thus, when the UASB is connected in series with the SBR and then the refinery wastewater to be treated is biochemically treated, the settling time S is used as the operation parameter of the SBR.
The culture and acclimation of the anaerobic granular sludge and the aerobic granular sludge can be performed separately.
Through a plurality of tests, when the oil refining wastewater is treated by the biochemical treatment method, the anaerobic granular sludge and the aerobic granular sludge obtained by the method can obviously improve the treatment effect, so that the oil content in the discharged water is less than or equal to 5mg/L, the COD (chemical oxygen demand) is less than or equal to 50mg/L, the ammonia nitrogen is less than or equal to 5mg/L, the total nitrogen is less than or equal to 40mg/L, compared with the wastewater before treatment, the COD can be reduced by more than 90%, the ammonia nitrogen and the total nitrogen can be reduced by more than 85%, and the COD, the ammonia nitrogen and the total nitrogen in the discharged water meet the discharge standard of pollutants for petroleum refining industry (GB 31570-2015).
In addition, when the oil refining wastewater to be treated has poor water quality and excessively high pollutant concentration (the oil content is more than 200mg/L), biochar fine particles or activated carbon with the particle size of 0.075-0.15mm can be added into an anaerobic sludge system and an aerobic sludge system respectively when the anaerobic granular sludge and the aerobic granular sludge are cultured and domesticated, and the addition amount is 3 percent of the effective volume of the UASB or SBR. The biochar fine particles or the activated carbon can accelerate the efficiency of sludge granulation, thereby realizing the high-efficiency treatment of the oil refining wastewater to be treated.
Wherein, the biochar fine particles can be purchased commercially or prepared by utilizing excess sludge of refineries. Specifically, the sludge is dried at 90 ℃, and then placed in a tubular pyrolysis furnace to be pyrolyzed for 3 hours at 700 ℃ in a nitrogen environment, so as to obtain a pyrolysis solid product. And soaking the pyrolysis solid product in a 3% HCl solution for 24h, then washing the pyrolysis solid product with deionized water until the pH value is 7, drying the pyrolysis solid product at 90 ℃, and grinding the pyrolysis solid product, and then sieving the pyrolysis solid product with 100-mesh and 200-mesh sieves to obtain the target particle size, namely the biochar fine particles.
In the process of culturing and domesticating the anaerobic granular sludge and the aerobic granular sludge, the diluted product of the oil refining wastewater to be treated, which is added with the co-culture matrix, is used as the wastewater for culturing and domesticating, and the proportion of the oil refining wastewater is continuously increased in the process of culturing and domesticating, so that the anaerobic granular sludge and the aerobic granular sludge which have high biochemical degradation effect on the oil refining wastewater to be treated are finally obtained. And the proper operation parameters of the UASB anaerobic reactor and the SBR aerobic reactor which can meet the serial arrangement are obtained through the culture domestication process, thereby further ensuring the effective biochemical treatment of the oil refining wastewater.
After the culture and domestication of the anaerobic granular sludge and the aerobic granular sludge are completed according to the method, or the granular sludge which reaches the standard of the culture and domestication is placed in a corresponding reactor, the UASB and the SBR can be connected in series to carry out the biochemical treatment of the oil refining wastewater.
Before the refinery waste water to be treated is introduced into the UASB, the refinery waste water to be treated is subjected to necessary pretreatment including removal of impurities (adsorption method may be used) and possible dilution treatment so that the oil content of the refinery waste water to be treated entering the UASB is not higher than 300 mg/L.
Introducing the oil refining wastewater to be treated meeting the parameters into UASB, and then retaining for a time T by using water powerNOperating the UASB, contacting the oil refining wastewater to be treated with cultured and domesticated anaerobic granular sludge in the UASB to perform anaerobic treatment, detecting and adjusting the COD and the pH of the wastewater discharged from the UASB to make the COD of the wastewater be 200 and 600mg/L, pH be 6.5-7.5, and then entering the SBR to perform aerobic treatment, wherein in the operating parameters of the SBR, the water inlet time, the aeration time, the water discharge time and the idle time are the same as those in the steps a) and b), and the settling time is S.
In order to adjust the COD and the pH of the water fed into the SBR, a buffer tank is connected between the UASB and the SBR in series, and the COD and the pH of the wastewater discharged from the UASB are adjusted in the buffer tank, so that the requirements of the SBR on the COD and the pH of the water fed into the SBR are met.
After the oil refining wastewater is treated by the method, the oil content in the discharged water is less than or equal to 5mg/L, the COD (chemical oxygen demand) is less than or equal to 50mg/L, the ammonia nitrogen is less than or equal to 5mg/L, and the total nitrogen is less than or equal to 40 mg/L.
Further, if the total nitrogen in the treated effluent is higher than 40mg/L, the aeration mode of SBR can be adjusted after the step b), so that the removal effect on the total nitrogen is improved.
Specifically, on the basis of the step b), the aeration mode in the SBR is set to be a stage aeration mode, namely an anoxic section is added in the aeration stage, and the stage aeration mode sequentially comprises a first aeration mode, a first explosion-stopping mode, a second aeration mode, a second explosion-stopping mode and a third aeration mode; the first aeration time is 10-15min, the first explosion-stopping time is 100-110min, the second aeration time is 30-35min, the second explosion-stopping time is 50-60min, and the third aeration time is 50-70 min. The remaining time parameters of the SBR run were unchanged and the settling time was S.
By executing the aeration method after the step b), the total nitrogen removal rate is not lower than 85%, and the aeration flow can be further adjusted, so that the dissolved oxygen of the nitrification section in the SBR is more than 8mg/L, and the dissolved oxygen of the denitrification section is less than 2mg/L, thereby ensuring the anoxic environment and preventing the carbon-containing substances in the wastewater from being too quickly consumed, and further improving the denitrification effect.
If the adjustment of the aeration mode is included in the process of culturing and acclimating the aerobic granular sludge, the SBR needs to be operated according to the aeration mode in the biochemical treatment of the oil refining wastewater to be treated by the UASB and the SBR in series.
The invention adopts the granular sludge technology of UASB + SBR, reduces the volume and the occupied area of the reactor, improves the treatment load, avoids the sludge loss and does not need to arrange a secondary sedimentation tank; compared with flocculent sludge, the granular sludge has higher biomass and stronger impact resistance, and is less prone to sludge bulking; by controlling the process conditions and the operation parameters, the high-efficiency treatment of the oil refining wastewater can be realized, the treated water quality meets the requirements of the national relevant standards, and the economic benefit is obvious.
Drawings
FIG. 1 is a graph showing the change in particle size of anaerobic granular sludge and aerobic granular sludge during culture and acclimation in accordance with embodiment 1 of the present invention;
FIG. 2 is a schematic view showing the effect of biochemical treatment of refinery waste water in example 1 of the present invention;
FIG. 3 is a graph showing the change in particle size of anaerobic granular sludge and aerobic granular sludge during culture and acclimation in accordance with example 2 of the present invention;
FIG. 4 is a schematic view showing the effect of biochemical treatment of refinery wastewater in example 2 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
The treatment object of the embodiment is oily wastewater of a certain refinery, and the oily wastewater is subjected to dilution treatment and oil removal pretreatment to obtain the to-be-treated oil refining wastewater with oil content of 150-170mg/L, COD of 800-1000mg/L and ammonia nitrogen of 8-25 mg/L. The amount of the treated water was 0.2m in terms of volume of UASB and SBR3/d。
The first inlet water is a dilution product of the oil refining wastewater to be treated and is used for culturing and domesticating anaerobic granular sludge, the oil content of the first inlet water is 120mg/L, and the COD is 500-600 mg/L;
the second inlet water is a dilution product of the oil refining wastewater to be treated and is used for culturing and domesticating aerobic granular sludge, the oil content of the second inlet water is 70mg/L, and the COD is 200-300 mg/L;
the biochemical treatment of the oil refining wastewater in the embodiment comprises the following steps:
1. culture domestication of anaerobic granular sludge
1) The UASB is inoculated with flocculent sludge in a hydrolysis acidification reaction tank of the plant, and the inoculation amount is 30 percent of the effective volume of the reactor. Subsequently adding a first feed water containing co-culture medium to the UASB, the co-culture medium comprising glucose (carbon source) and nutrients, wherein the initial concentration of glucose in the first feed water is 1000mg/L, and the nutrients comprise NH4Cl、KH2PO4、NaHCO3And FeCl2 1275μg/L，CoCl2 1091μg/L，EDTA 994μg/L，MnSO4 888μg/L，ZnSO460μg/L，NiCl232μg/L，(NH4)6Mo7O24 47μg/L，H2BO3 49μg/L，CuCl219 μ g/L. Wherein NH4Cl and KH2PO4Ensuring COD: n: p is 500:5:1, NaHCO3The alkalinity of the first inlet water is controlled to be 1000-3000 mg/L.
The UASB is operated for 28h as the hydraulic retention time until the gas production rate in the UASB is more than 0.5m3/m3D, volume of methaneMeasurement of>60% and COD removal rate>80%, at this time, the UASB operation takes 30 days totally, and the sludge particle size in the UASB is gradually increased at a sludge concentration of 6000-8000 mg/L.
2) Adjusting COD of first oil refining wastewater entering UASB
The method specifically comprises the following steps:
adding the oil refining wastewater to be treated into the first inlet water to increase COD (chemical oxygen demand) to 1000mg/L, introducing the first inlet water as adjusted first inlet water into a UASB (upflow anaerobic sludge blanket), operating the UASB by taking 28h as hydraulic retention time T, and performing subsequent adjustment on glucose content and hydraulic retention time after the UASB is monitored to stably operate for 5 days with methane volume content of more than 55% and COD removal rate of more than 70%;
3) anaerobic acclimation treatment (wherein, COD of the first inlet water is 1000mg/L)
The method specifically comprises the following steps:
first anaerobic acclimation treatment: reducing the concentration of glucose in the first inlet water to 800mg/L, introducing the glucose into UASB, operating the UASB by taking 24h as hydraulic retention time, and performing second adjustment on the concentration of the glucose in the first inlet water and the hydraulic retention time to perform second anaerobic acclimation treatment after the UASB is stably operated for 5 days by monitoring that the volume content of methane is greater than 55% and the removal rate of COD is greater than 70%;
and (3) anaerobic domestication treatment for the second time: reducing the concentration of glucose in the first inlet water to 600mg/L, introducing the glucose into UASB, operating the UASB by taking 20h as hydraulic retention time, and after the UASB is stably operated for 5 days by monitoring that the volume content of methane is more than 55% and the removal rate of COD is more than 70%, carrying out third adjustment on the concentration of the glucose in the first inlet water and the hydraulic retention time to carry out third anaerobic acclimation treatment;
and (3) anaerobic domestication treatment for the third time: reducing the concentration of glucose in the first inlet water to 400mg/L, introducing the glucose into UASB, operating the UASB by taking 16h as hydraulic retention time, and performing fourth adjustment on the concentration of the glucose in the first inlet water and the hydraulic retention time to perform fourth anaerobic acclimation treatment after the UASB is stably operated for 5 days with the methane volume content of more than 55% and the COD removal rate of more than 70%;
fourth anaerobic acclimation treatment: adjusting the concentration of glucose in the first inlet water to 200mg/L, introducing the glucose into UASB, operating the UASB by taking 12h as hydraulic retention time, and performing fifth adjustment on the concentration of the glucose in the first inlet water and the hydraulic retention time to perform fifth anaerobic acclimation treatment after the UASB is stably operated for 5 days with the methane volume content of more than 55% and the COD removal rate of more than 70%;
fifth anaerobic acclimation treatment: adjusting the concentration of glucose in the first oil refining wastewater to 0mg/L, introducing the glucose into UASB (upflow anaerobic sludge blanket), and operating the UASB for 12h as hydraulic retention time until the UASB is stably operated for 5 days with the volume content of methane being more than 55% and the removal rate of COD being more than 70%, thereby completing the culture and domestication of the anaerobic granular sludge.
The process takes 120 days, the particles with the particle size of more than 0.46nm in the granular sludge obtained by culture and domestication account for 50 wt% of the total granular sludge, and the SVI is 33 mL/g.
2. Culture domestication of aerobic granular sludge
1) The SBR was inoculated with the flocculent activated sludge in the aerobic tank of the plant in an amount of 57% of the reactor volume. Then introducing second inlet water containing a culture medium into the SBR, wherein the co-culture medium comprises glucose (carbon source) and nutrient elements, the initial concentration of the glucose in the second inlet water is 600mg/L, and the nutrient elements comprise NH4Cl、KH2PO4And H3BO3 50μg/L，ZnCl2 50μg/L，CuCl2 30μg/L，MnSO4 45μg/L，(NH4)6Mo7O24 47μg/L，AlCl3 50μg/L，CoCl2 27μg/L，NiCl2 50μg/L，KI 30μg/L，MgCl2 97μg/L，FeCl2 9μg/L，CaCl223. mu.g/L. Wherein NH4Cl and KH2PO4Ensuring COD: n: p is 100:5: 1.
2) Aerobic culture treatment
The method specifically comprises the following steps:
aerobic culture treatment for the first time: after the second inlet water with the composition is introduced into the SBR with the water inlet time of 13min, the SBR is operated to carry out the first aerobic culture treatment with the aeration time of 222min, the sedimentation time of 30min, the water discharge time of 13min and the idle time of 10min until the residual mass of the aerobic sludge is 80 percent of the initial adding amount of the aerobic sludge, the concentration of the aerobic sludge is 6000mg/L and the SVI is less than 100mL/g, and the second aerobic culture treatment is carried out;
and (3) aerobic culture treatment for the second time: after the second inlet water with the composition is introduced into the SBR with the water inlet time of 13min, the SBR is operated to carry out second aerobic culture treatment with the aeration time of 222min, the sedimentation time of 15min, the water discharge time of 13min and the idle time of 10min until the residual mass of the aerobic sludge is 60-70% of the initial aerobic sludge addition, the aerobic sludge concentration is 3000-5000mg/L and the SVI is less than 50mL/g, and third aerobic culture treatment is carried out;
and (3) aerobic culture treatment for the third time: and (3) after the second inlet water with the composition is introduced into the SBR for 13min, operating the SBR for the third aerobic culture treatment with the aeration time of 222min, the sedimentation time of 15min, the drainage time of 13min and the idle time of 10min until the residual mass of the aerobic sludge is 50-60% of the initial aerobic sludge addition, the aerobic sludge concentration is 2500mg/L and the SVI is less than 40mL/g, and finishing the aerobic culture treatment.
The process takes 35 days, the particles with the particle size of more than 0.46nm in the granular sludge obtained by culture account for 60 wt% of the total granular sludge, and the SVI is 30 mL/g.
3) Aerobic acclimatization treatment
The method specifically comprises the following steps:
first aerobic acclimation treatment: reducing the concentration of glucose in the second inlet water to 400mg/L by taking the inlet water time as 13min, introducing the glucose into SBR, performing first aerobic acclimation treatment by taking the aeration time as 222min, the settling time as 5min, the drainage time as 13min and the idle time as 10min, and performing second aerobic acclimation treatment by performing second adjustment on the concentration of the glucose in the second inlet water after the SBR is monitored to stably run for 10 days at a COD removal rate of more than 90%;
and (3) aerobic domestication treatment for the second time: reducing the concentration of the glucose in the second influent water to 200mg/L by taking the influent water time as 13min, carrying out second aerobic acclimation treatment by taking the aeration time as 222min, the settling time as 5min, the drainage time as 13min and the idle time as 10min, and carrying out third aerobic acclimation treatment by carrying out third adjustment on the concentration of the glucose in the second oil refining wastewater after the stable operation of SBR with the COD removal rate of more than 90% for 10 days is monitored;
and (3) aerobic acclimation treatment for the third time: and (3) reducing the concentration of glucose in the second inlet water to 0 (namely, no glucose is added into the co-culture substrate) by taking the inlet water time as 13min, carrying out third aerobic acclimation treatment by taking the aeration time as 222min, the settling time as 5min, the drainage time as 13min and the idle time as 10min, and finishing the culture acclimation of the aerobic granular sludge after the SBR is stably operated for 10 days at the COD removal rate of more than 90%.
FIG. 1 is a graph showing the change in particle size of anaerobic granular sludge and aerobic granular sludge during culture and acclimation in accordance with example 1 of the present invention. As is clear from fig. 1, the method of the present embodiment is suitable because the anaerobic granular sludge and the aerobic granular sludge can be obtained by culture and acclimation, the obtained anaerobic granular sludge and aerobic granular sludge do not disintegrate after the long-term operation of the reactor, and the aerobic granular sludge formation cycle is short.
3. Biochemical treatment of oil refining waste water to be treated
And (2) connecting UASB and SBR in series, wherein the UASB is operated according to the hydraulic retention time of 12 hours, and the SBR is operated according to the conditions of water inlet for 13min, aeration for 222min, sedimentation for 5min, water drainage for 13min and idle for 10 min. Wherein the inlet water COD of SBR is 300-350mg/L, pH is 7.5.
Introducing the oil refining wastewater to be treated into UASB and finally discharging from SBR, starting on day 21, always keeping COD effluent of the wastewater discharged from SBR below 50mg/L, the total COD removal rate is more than 95%, effluent petroleum is less than or equal to 5mg/L, ammonia nitrogen is less than or equal to 8mg/L, and total nitrogen is less than or equal to 40mg/L, thus meeting the emission standard of petroleum refining industry pollutants (GB 31570-2015).
FIG. 2 is a schematic view showing the effect of biochemical treatment of refinery wastewater in example 1 of the present invention. As shown in FIG. 2, the refinery waste water biochemical treatment method of the embodiment can effectively reduce the COD content of the refinery waste water to be treated, and the granular sludge of the present invention can stably exist and carry out efficient biochemical treatment on the refinery waste water when continuously operating for 130 days.
Example 2
The treatment object of the embodiment is the oily wastewater of a heavy oil refinery, and the oily wastewater is subjected to dilution treatment and oil removal pretreatment to obtain the to-be-treated oil refining wastewater with the oil content of 250-280mg/L, the COD of 1500-2500mg/L and the ammonia nitrogen of 8-25 mg/L. The amount of treated water was 1.8m in terms of volume of UASB and SBR3/d。
The first inlet water is a dilution product of the oil refining wastewater to be treated and is used for culturing and domesticating anaerobic granular sludge, the oil content of the first oil refining wastewater is 120mg/L, and the COD is 500-600 mg/L;
the second inlet water is a dilution product of the oil refining wastewater to be treated and is used for culturing and domesticating aerobic granular sludge, the oil content of the second inlet water is 70mg/L, and the COD is 200-300 mg/L;
the biochemical treatment of the oil refining wastewater in the embodiment comprises the following steps:
1. culture domestication of anaerobic granular sludge
1) The UASB is inoculated with the flocculent sludge in the hydrolytic acidification reaction tank of the plant, and the inoculation amount is 30 percent of the total volume of the reactor. Meanwhile, biochar fine particles are added to promote sludge granulation, and the activated carbon is prepared from the excess sludge of the plant, the particle size is 0.1-0.5mm, and the addition amount is 3% of the effective volume of the UASB. Subsequently adding a second influent water containing co-culture medium to the UASB, the co-culture medium comprising glucose (carbon source) and nutrient elements, wherein the initial concentration of glucose in the second influent water is 1000mg/L, and the nutrient elements comprise NH4Cl、KH2PO4、NaHCO3And FeCl2 1275μg/L，CoCl2 1091μg/L，EDTA 994μg/L，MnSO4888μg/L，ZnSO4 60μg/L，NiCl232μg/L，(NH4)6Mo7O2447μg/L，H2BO3 49μg/L，CuCl219 μ g/L. Wherein NH4Cl and KH2PO4Ensuring COD: n: p is 500:5:1, NaHCO3The alkalinity of the first inlet water is controlled to be 1000-3000 mg/L.
UASB takes 28h as hydraulic retention timeAnd (4) performing the operation until the gas production rate in the UASB is more than 0.5m3/m3D, volume content of methane>60% and COD removal rate>80%, in this case, the UASB operation takes 50 days, and the particles having a particle size of more than 0.46nm in the UASB account for 30 wt% of the total granular sludge. Wherein, when the UASB is operated to the 30 th day, the sludge concentration in the UASB is 8000-10000mg/L, and the sludge particle size is gradually increased.
2) Adjusting COD of first oil refining wastewater entering UASB
The method specifically comprises the following steps:
adding the oil refining wastewater to be treated into the first inlet water to increase COD to 1000mg/L, introducing the first inlet water as adjusted first inlet water into a UASB (upflow anaerobic sludge blanket), operating the UASB for 28h as hydraulic retention time T, and performing secondary adjustment on the COD of the first oil refining wastewater after the UASB is monitored to stably operate for 5 days with the methane volume content of more than 55% and the COD removal rate of more than 70%;
adding wastewater to be treated into the first influent water with the COD of 1000mg/L to increase the COD to 1500mg/L, introducing the wastewater to be treated into UASB as adjusted first influent water, operating the UASB by using 28h as hydraulic retention time T, and performing third adjustment on the COD of the first oil refining wastewater after the UASB is monitored to stably operate for 5 days with the methane volume content of more than 55% and the COD removal rate of more than 70%;
adding wastewater to be treated into the first influent water with the COD of 1500mg/L to increase the COD to 2000mg/L, introducing the wastewater to be treated into UASB as adjusted first influent water, operating the UASB by using 28h as hydraulic retention time T, and performing fourth adjustment on the COD of the first oil refining wastewater after the UASB is monitored to stably operate for 5 days with the methane volume content of more than 55% and the COD removal rate of more than 70%;
adding wastewater to be treated into the first inlet water with COD of 2000mg/L to increase COD to 2000mg/L, introducing the first inlet water as adjusted first inlet water into UASB, and operating the UASB by using 28h as hydraulic retention time T until the UASB is stably operated for 5 days with methane volume content of 55% and COD removal rate of 70%, and then carrying out subsequent regulation on glucose content.
3) Anaerobic acclimation treatment (wherein COD of the first influent water is 2500mg/L)
The method specifically comprises the following steps:
first anaerobic acclimation treatment: reducing the concentration of glucose in the first inlet water to 800mg/L, introducing the glucose into UASB, operating the UASB by taking 24h as hydraulic retention time, and performing second adjustment on the concentration of the glucose in the first inlet water and the hydraulic retention time to perform second anaerobic acclimation treatment after the UASB is stably operated for 5 days by monitoring that the volume content of methane is greater than 55% and the removal rate of COD is greater than 70%;
and (3) anaerobic domestication treatment for the second time: reducing the concentration of glucose in the first inlet water to 600mg/L, introducing the glucose into UASB, operating the UASB by taking 20h as hydraulic retention time, and after the UASB is stably operated for 5 days by monitoring that the volume content of methane is more than 55% and the removal rate of COD is more than 70%, carrying out third adjustment on the concentration of the glucose in the first inlet water and the hydraulic retention time to carry out third anaerobic acclimation treatment;
and (3) anaerobic domestication treatment for the third time: reducing the concentration of glucose in the first inlet water to 400mg/L, introducing the glucose into UASB, operating the UASB by taking 16h as hydraulic retention time, and performing fourth adjustment on the concentration of the glucose in the first inlet water and the hydraulic retention time to perform fourth anaerobic acclimation treatment after the UASB is stably operated for 5 days with the methane volume content of more than 55% and the COD removal rate of more than 70%;
fourth anaerobic acclimation treatment: adjusting the concentration of glucose in the first inlet water to 200mg/L, introducing the glucose into UASB, operating the UASB by taking 12h as hydraulic retention time, and performing fifth adjustment on the concentration of the glucose in the first inlet water and the hydraulic retention time to perform fifth anaerobic acclimation treatment after the UASB is stably operated for 5 days with the methane volume content of more than 55% and the COD removal rate of more than 70%;
fifth anaerobic acclimation treatment: adjusting the concentration of glucose in the first oil refining wastewater to 0mg/L, introducing the glucose into UASB (upflow anaerobic sludge blanket), and operating the UASB for 12h as hydraulic retention time until the UASB is stably operated for 5 days with the volume content of methane being more than 55% and the removal rate of COD being more than 70%, thereby completing the culture and domestication of the anaerobic granular sludge.
The process takes 120 days, the particles with the particle size of more than 0.46nm in the granular sludge obtained by culture and domestication account for 50 wt% of the total granular sludge, and the SVI is 28 mL/g.
2. Culture domestication of aerobic granular sludge
1) And inoculating the flocculent activated sludge in the aerobic tank of the plant into SBR, wherein the inoculation amount is 50 percent of the effective volume of the reactor. Meanwhile, biochar fine particles are added to promote sludge granulation, and the activated carbon is prepared from the excess sludge of the plant, the particle size is 0.075-0.15mm, and the addition amount is 3% of the effective volume of the SBR. Then introducing second inlet water containing a culture medium into the SBR, wherein the co-culture medium comprises glucose (carbon source) and nutrient elements, the initial concentration of the glucose in the second inlet water is 600mg/L, and the nutrient elements comprise NH4Cl、KH2PO4And H3BO3 50μg/L，ZnCl2 50μg/L，CuCl2 30μg/L，MnSO445μg/L，(NH4)6Mo7O24 47μg/L，AlCl3 50μg/L，CoCl2 27μg/L，NiCl2 50μg/L，KI 30μg/L，MgCl2 97μg/L，FeCl2 9μg/L，CaCl223. mu.g/L. Wherein NH4Cl and KH2PO4Ensuring COD: n: p is 100:5: 1.
2) Aerobic culture treatment
Aerobic culture treatment for the first time: after the second inlet water with the composition is introduced into the SBR for 14min of water inlet time, the SBR is operated for carrying out first aerobic culture treatment with the aeration time of 265min, the sedimentation time of 30min, the water discharge time of 14min and the idle time of 10min until the residual mass of the aerobic sludge is 80% of the initial adding amount of the aerobic sludge, the concentration of the aerobic sludge is about 5000mg/L and the SVI is less than 100 mL/g;
and (3) aerobic culture treatment for the second time: after the second inlet water with the composition is introduced into the SBR for 14min of water inlet time, the SBR is operated for carrying out second aerobic culture type treatment by taking the aeration time as 265min, the sedimentation time as 15min, the drainage time as 14min and the idle time as 10min until the residual mass of the aerobic sludge is about 70 percent of the initial adding amount of the aerobic sludge, the concentration of the aerobic sludge is about 3500mg/L and the SVI is less than 50 mL/g;
and (3) aerobic culture treatment for the third time: and (3) after the second inlet water with the composition is introduced into the SBR for 14min of water inlet time, operating the SBR for the third aerobic culture treatment with the aeration time of 265min, the settling time of 5min, the water discharge time of 14min and the idle time of 10min until the residual mass of the aerobic sludge is 50-60% of the initial addition amount of the aerobic sludge, the concentration of the aerobic sludge is 2800mg/L and the SVI is less than 40mL/g, and finishing the aerobic culture treatment.
The particles with the sludge particle size of more than 0.46mm account for 65 wt% of the total granular sludge.
3) Aerobic acclimatization treatment
The method specifically comprises the following steps:
first aerobic acclimation treatment: reducing the concentration of the glucose in the second inlet water to 400mg/L by taking the inlet water time as 14min, introducing the glucose into SBR, performing first aerobic acclimation treatment by taking the aeration time as 265min, the settling time as 5min, the drainage time as 14min and the idle time as 10min, and performing second aerobic acclimation treatment by performing second adjustment on the concentration of the glucose in the second inlet water after the SBR is monitored to stably run for 10 days at a COD removal rate of more than 90%;
and (3) aerobic domestication treatment for the second time: reducing the concentration of the glucose in the second inlet water to 200mg/L by taking the inlet water time as 14min, introducing the glucose into SBR, performing second aerobic acclimation treatment by taking the aeration time as 265min, the sedimentation time as 5min, the drainage time as 14min and the idle time as 10min, and performing third aerobic acclimation treatment by performing third adjustment on the concentration of the glucose in the second inlet water after the SBR is monitored to stably run for 10 days at a COD removal rate of more than 90%;
and (3) aerobic acclimation treatment for the third time: and (3) reducing the concentration of glucose in the third inlet water to 0 (namely, not adding glucose in the co-culture substrate) by taking the inlet water time as 14min, carrying out third aerobic acclimation treatment by taking the aeration time as 265min, the settling time as 5min, the drainage time as 14min and the idle time as 10min, and finishing the culture acclimation of the aerobic granular sludge after monitoring that the SBR stably runs for 10 days at the COD removal rate of more than 90%.
FIG. 3 is a graph showing the change in particle size of anaerobic granular sludge and aerobic granular sludge during culture and acclimation in accordance with example 2 of the present invention. As is clear from fig. 3, the method of the present embodiment is suitable because the anaerobic granular sludge and the aerobic granular sludge can be obtained by culture and acclimation, the obtained anaerobic granular sludge and aerobic granular sludge do not disintegrate after the long-term operation of the reactor, and the aerobic granular sludge formation cycle is short.
4. Adjustment of aeration mode
And (3) adding no more glucose into the second inlet water, and operating SBR with the water inlet time of 14min, the settling time of 5min, the water discharge time of 14min and the idle time of 10min, wherein the aeration mode comprises first aeration, first explosion stopping, second aeration, second explosion stopping and third aeration, the first aeration time is adjusted within 10-15min, the first explosion stopping time is adjusted within 100-110min, the second aeration time is adjusted within 30-35min, the second explosion stopping time is adjusted within 50-60min, and the third aeration time is adjusted within 50-70 min.
When the first aeration time is 15min, the first explosion suspension time is 105min, the second aeration time is 30min, the second explosion suspension time is 60min, and the third aeration time is 55min, the total nitrogen removal rate in the SBR is monitored to be 85%, and thus the above aeration mode is used as the final aeration mode for acclimating the aerobic granular sludge.
3. Biochemical treatment of oil refining waste water to be treated
And (2) connecting UASB and SBR in series, operating the UASB according to the hydraulic retention time of 12 hours, operating the SBR according to the water inlet time of 14min, aerating (the first aeration time is 15min, the first explosion-stopping time is 105min, the second aeration time is 30min, the second explosion-stopping time is 60min, and the third aeration time is 55min), settling for 5min, draining for 14min, and operating the SBR in an idle state for 10 min. Wherein the COD of the inlet water of SBR is 250-450mg/L, pH and is 7.5.
The oil refining wastewater to be treated is introduced into UASB and finally discharged from SBR, COD of the wastewater discharged from SBR is always lower than 50mg/L, the removal rate of the total COD is higher than 95%, effluent petroleum is less than or equal to 5mg/L, ammonia nitrogen is less than or equal to 8mg/L, and total nitrogen is less than or equal to 40mg/L, thereby meeting the discharge standard of petroleum refining industrial pollutants (GB 31570-2015).
FIG. 4 is a schematic view showing the effect of biochemical treatment of refinery wastewater in example 2 of the present invention. As shown in FIG. 4, the refinery waste water biochemical treatment method of the embodiment can effectively reduce the COD content of the refinery waste water to be treated, and the granular sludge of the present invention can stably exist and carry out efficient biochemical treatment on the refinery waste water when continuously operated for 130 days.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (5)

1. A biochemical treatment method of oil refining wastewater, characterized in that a UASB anaerobic reactor and an SBR aerobic reactor which are arranged in series are utilized, and a cultured and domesticated anaerobic granular sludge and an aerobic granular sludge are respectively arranged in the anaerobic reactor and the SBR aerobic reactor, the treatment method comprises the following processes:
operating UASB and SBR, introducing the oil refining wastewater to be treated into the UASB to perform anaerobic treatment, introducing the wastewater after the anaerobic treatment into the SBR to perform aerobic treatment after the wastewater is discharged, and discharging the wastewater, wherein the oil content of the oil refining wastewater to be treated is not higher than 300mg/L, and the COD of the wastewater entering the SBR is 200-600mg/L, pH and is 6.5-7.5;
the anaerobic granular sludge is prepared by culturing and domesticating the following processes:
1) adding hydrolytic acidification sludge and co-culture matrix into UASB, introducing diluted oil refining wastewater to be treated as inlet water, and operating until the gas production rate in UASB is greater than 0.5m by using hydraulic retention time T3/m3D, volume content of methane>60% and COD removal rate>80%；
2) Increasing COD of the inlet water in a staged manner and operating the UASB for a hydraulic retention time T until the COD of the inlet water is the same as the COD of the refinery wastewater to be treated, the volume content of methane in the UASB is more than 55%, and the removal rate of the COD is more than 70%;
3) stepwise reducing the carbon source content and operating the UASB with stepwise reduced hydraulic retention time until the carbon source content is zero and the hydraulic retention time is TNVolume content of methane in UASB>55% removal rate of COD>70 percent, completing the culture and domestication of the anaerobic granular sludge;
wherein, TN＜T；
The step 3) comprises the following steps: carrying out anaerobic domestication treatment for N times, wherein N is more than or equal to 5;
the number of times of the anaerobic acclimation treatment is recorded as S = {1,2, …, i-1, i, …, N };
the amount of the carbon source added in the (i-1) th anaerobic acclimation treatment is larger than that added in the ith anaerobic acclimation treatment;
hydraulic retention time T of (i-1) th anaerobic acclimation treatmenti-1The hydraulic retention time T is longer than the hydraulic retention time T of the ith anaerobic acclimation treatmenti；
In the Nth anaerobic acclimation treatment, the amount of the added carbon source is zero;
the aerobic granular sludge is prepared by culturing and domesticating the following processes:
a) adding aerobic activated sludge and a co-culture substrate into SBR, introducing diluted oil refining wastewater to be treated as inlet water, and reducing the sedimentation time of the SBR in a staged manner until SVI of the sludge in the SBR is less than 40mL/g when the sedimentation time is S;
b) reducing the carbon source content in a staged manner, and operating the SBR within the settling time S until the carbon source content is zero and the COD removal rate in the SBR is more than 90 percent, thereby completing the culture and domestication of the aerobic granular sludge; wherein, the COD of the SBR inlet water is less than the initial COD of the UASB inlet water;
the step a) comprises the following steps: carrying out aerobic culture treatment for K times, wherein K is more than or equal to 3;
the number of times of aerobic culture treatment is set as P = {1,2, …, g-1, g, …, K };
sedimentation time S of the (g-1) th aerobic culture treatmentg-1The settlement time S is longer than the settlement time S of the g-th aerobic culture treatmentg；
The sedimentation time of the K-th aerobic culture treatment is S;
the step b) comprises the following steps: m times of aerobic domestication treatment, wherein the settling time of each time of the aerobic domestication treatment is S, and M is more than or equal to 3;
the number of times of the aerobic acclimation treatment is recorded as Q = {1,2, …, j-1, j, …, M };
wherein the amount of the carbon source added in the (j-1) th aerobic acclimation treatment is larger than that in the j th aerobic acclimation treatment;
in the M-th aerobic acclimation treatment, the amount of the added carbon source is zero;
in the process of culturing and domesticating the anaerobic granular sludge, the alkalinity of inlet water is 2000-3000mg/L, the oil content is not higher than 200mg/L, COD and is 500-600mg/L, and the mass ratio of the inlet water COD to N, P elements in the co-culture medium is (350-500): 5: 1; and/or the presence of a gas in the gas,
in the process of culturing and domesticating the aerobic granular sludge, the oil content of inlet water is not higher than 100mg/L, COD and is 200-500mg/L, and the mass ratio of the COD of the inlet water to N, P elements in a co-culture substrate is 100: (3-5): 1;
the oil content in the discharged water treated by the treatment method is less than or equal to 5mg/L, the COD is less than or equal to 50mg/L, the ammonia nitrogen is less than or equal to 5mg/L, and the total nitrogen is less than or equal to 40 mg/L.
2. The biochemical treatment method of refinery waste water according to claim 1,
the Co-culture medium of UASB contains nutrient elements including Fe, Zn, Co, Mn, Ni, B, Cu, K, Na, N, Mo, Cl, S and P;
the culture medium of SBR contains nutrient elements which comprise Fe, Zn, Co, Al, I, Mg, Ca, Mn, Ni, B, Cu, K, Na, N, Mo, Cl, S and P.
3. The biochemical treatment method of refinery wastewater according to claim 1, wherein said anaerobic treatment has a hydraulic retention time TN。
4. The biochemical treatment method of refinery-related wastewater according to claim 1, wherein the sedimentation time of said aerobic treatment in said treatment method is S.
5. The biochemical treatment method of refinery wastewater according to claim 4, further comprising setting the aeration mode of SBR to be a phase aeration mode after step b):
the stage aeration mode sequentially comprises the following steps:
first aeration, first explosion stopping, second aeration, second explosion stopping and third aeration;
the first aeration time is 10-15min, the first explosion-stopping time is 100-110min, the second aeration time is 30-35min, the second explosion-stopping time is 50-60min, and the third aeration time is 50-70 min.
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