Emergency treatment method for early warning of abnormality of salt-containing sewage treatment system

Abstract

The application discloses an emergency treatment method for early warning of abnormality of a salt-containing sewage treatment system. The method comprises the following steps: the salt-containing sewage treatment adopts an anaerobic-aerobic combined process; when abnormal nitrous nitrogen concentration is detected in effluent in the running process, a supplement system is started, active sludge is added into the salt-containing sewage, and a bacterial agent and tetrahydropyrimidine are supplemented; after the supplement, no sludge is discharged until the nitrous nitrogen concentration is less than 1 mg / L, and the supplement system is stopped. The method can make timely treatment for early warning of abnormality of the salt-containing sewage system, quickly eliminate the impact risk, shorten the system recovery time, save resources, reduce the cost, and ensure long-period stable operation of the system.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to an emergency response method for early warning anomalies in a saline wastewater treatment system. Background Technology

[0002] Existing enterprises generally construct wastewater treatment systems based on the principle of "separate flow and separate treatment of wastewater" to achieve compliant wastewater treatment. However, with the deterioration of oil quality, the increasing complexity of production processes, the improvement of wastewater reuse rates, and the stringency of wastewater discharge standards, abnormal water quality is a common production problem faced by oil refinery wastewater treatment plants. This leads to a need to improve the operational stability and shock resistance of existing wastewater treatment systems. In particular, the pursuit of higher discharge standards often involves adding carbon sources and alkalinity to the wastewater treatment system, further increasing operating costs. The organic pollutants and alkalinity contained in the existing system wastewater result in significant waste.

[0003] CN202011175711.4 discloses an oil refinery wastewater treatment device and an emergency treatment method for abnormal water quality. The oil refinery wastewater treatment device includes a saline wastewater treatment system and an oily wastewater treatment system. The method mainly involves connecting the sludge outlet of the primary sedimentation tank of the oily wastewater treatment system to the sludge inlet pipes of the primary and secondary sedimentation tanks of the saline wastewater treatment system; and connecting the outlets of the primary and secondary biochemical treatment units of the saline wastewater treatment system to the inlet pipes of the secondary biochemical treatment unit of the oily wastewater treatment system. CN202221348155.0 discloses a combined HPPO wastewater and hydrogen peroxide wastewater treatment system. This system uses HPPO wastewater and hydrogen peroxide wastewater together, which can reduce some organic pollutants, improve the biodegradability of the wastewater, and significantly reduce the peroxide concentration in the hydrogen peroxide wastewater, achieving "waste treatment with waste" and meeting the requirements for entering a wastewater treatment plant.

[0004] CN102815788A discloses an emergency control method for the CASS process to cope with abnormal influent water quality shocks. The method includes the following steps: Based on online monitoring installed at the main inlet of the CASS wastewater treatment plant, it is determined whether the CASS reactor is about to be impacted by abnormal influent; if abnormal influent is detected entering the CASS reactor at a certain time, the CASS reactor in or about to enter the influent stage is adjusted to the lowest achievable filling ratio (f) and the highest sludge return ratio (R) according to the influent flow rate to create maximum buffering capacity; then, based on the water quality characteristics of the abnormal influent, the time allocation and corresponding dissolved oxygen concentration levels of the four stages (influent, aeration, sedimentation, and decanting) of the CASS reactor in or about to enter the influent stage within one operating cycle are controlled; if the situation is normal, the system operates in normal mode. However, this method only adjusts the CASS process operation method and its emergency control effect on abnormal influent water quality shocks is not ideal, and it cannot restore system function in a timely manner.

[0005] The methods described above all solve certain problems, but some only involve connecting pipelines and, in case of a malfunction, setting up emergency storage tanks to disconnect wastewater from the original treatment system. Some companies, lacking the space to install emergency storage tanks, still face the challenge of failing to meet standards during surges. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an emergency response method for early warning anomalies in saline wastewater treatment systems. This method enables timely handling of early warning anomalies in saline wastewater systems, rapidly eliminating the risk of impact, shortening system recovery time, saving resources, reducing costs, and ensuring the long-term stable operation of the system.

[0007] This invention provides an emergency handling method for early warning anomalies in a saline wastewater treatment system, comprising the following steps: The saline wastewater treatment adopts an anaerobic / aerobic combined process (A / O). During operation, when the nitrite nitrogen concentration in the effluent is 5-15 mg / L, activated sludge is added to the influent saline wastewater, and bacterial agents and tetrahydropyrimidine are supplemented. After the addition, the system does not discharge sludge until the nitrite nitrogen concentration is less than 1 mg / L, at which point the addition of activated sludge, bacterial agents, and tetrahydropyrimidine is stopped.

[0008] In the method of the present invention, the amount of activated sludge replenished is increased by 100-500 mg / L in the sludge concentration in the system after addition.

[0009] In the method of the present invention, the dosage of the bacterial agent is supplemented at a mass-volume ratio of 5-10 mg / L to the saline wastewater.

[0010] In the method of the present invention, the amount of tetrahydropyrimidine used is added at a mass ratio of 1-10 μg / kg (preferably 5-10 μg / kg) to the bacterial agent. Preferably, tetrahydropyrimidine and the bacterial agent are added simultaneously.

[0011] In the method of this invention, the activated sludge contains microorganisms capable of removing COD and nitrogenous pollutants, preferably activated sludge from the secondary sedimentation tank of an oil refinery wastewater biochemical treatment unit. The activated sludge contains MLSS of 5000-9000 mg / L.

[0012] In the method of this invention, the saline wastewater has a COD concentration of 200-800 mg / L, an ammonia nitrogen concentration of 50-100 mg / L, a total nitrogen concentration of 50-120 mg / L, and a salt content of 5000-20000 mg / L.

[0013] In the method of this invention, during operation, the ammonia nitrogen concentration in the system effluent is less than 8 mg / L, the total nitrogen concentration is less than 40 mg / L, and the COD concentration is less than 50 mg / L.

[0014] In this invention, the saline wastewater is treated using a conventional anaerobic / aerobic combined process (A / O). The general process includes: the saline wastewater first enters tank A for anaerobic treatment, then enters tank O for aerobic treatment. The wastewater after A / O treatment enters a subsequent sedimentation tank and is discharged after passing the qualified discharge. A nitrification liquid return pipeline can be installed between tank O and tank A, and a sludge return pipeline can be installed between the secondary sedimentation tank and tank A. The operating conditions for tank A are: dissolved oxygen 0.1–1.0 mg / L, preferably 0.2–0.5 mg / L, pH 7.0–8.5, and temperature 20–40℃; the operating conditions for tank O are: dissolved oxygen 1–5 mg / L, preferably 2–4 mg / L, pH 7.0–8.5, and temperature 20–40℃. During normal operation, the saline wastewater treatment system of this invention treats wastewater according to the traditional anaerobic / aerobic process. Generally, carbonization and nitrification reactions occur in tank O, while hydrolysis and denitrification reactions occur in tank A. During normal system operation, ammonia-oxidizing bacteria and nitrite-oxidizing bacteria simultaneously degrade pollutants during the nitrification process, preventing the accumulation of nitrite nitrogen. When the system malfunctions, nitrite-oxidizing bacteria are first inhibited, failing to convert nitrite nitrogen into nitrate nitrogen in a timely manner, leading to nitrite nitrogen accumulation. The activity of microorganisms within the system is affected, sludge gradually deflocculates, and settling performance deteriorates. As bacteria are lost, the ammonia nitrogen concentration in the effluent gradually increases, resulting in poor effluent quality and, in severe cases, system failure.

[0015] In the method of this invention, the abnormality refers to an increase in effluent nitrite concentration caused by at least one of water quality fluctuations, water volume fluctuations, and salinity. If not treated promptly and operation continues, ammonia nitrogen, total nitrogen, and COD concentrations will exceed the standards, and may even lead to activated sludge deflocculation and discharge with the water. It will take at least one month, or even longer, to restore a stable biological community of activated sludge in the acclimation system.

[0016] In the method of the present invention, the activated sludge can be replenished in an existing feasible manner, including connecting the device itself with pipelines, or replenishing across lines.

[0017] In the method of this invention, the bacterial agent is Halomonas nigrificans N2-2, which was deposited on March 18, 2024, at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 30065; the deposit address is: Institute of Microbiology, Chinese Academy of Sciences, No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing.

[0018] In the method of this invention, the *Halomonas nigrificans* N2-2 has a rod-shaped morphology, with milky-white, opaque colonies, regular edges, a raised surface, no halo, and a diameter of 1-2 mm. Its biological characteristics are: Gram-negative, catalase-positive, oxidase-positive, and urease-positive. This bacterium is a heterotrophic nitrifying bacterium capable of utilizing multiple carbon sources, preferably citrate.

[0019] In this invention, the cultivation method for Halomonas nigrificans N2-2 uses citrate culture medium and is cultured under aerobic conditions until the stationary phase. The citrate is at least one of sodium citrate, potassium citrate, etc. The culture medium also contains potassium nitrate, potassium dihydrogen phosphate, calcium chloride, etc. The culture medium may further contain ammonium sulfate, sodium chloride, and peptone. The cultivation conditions are: pH 6-9, temperature 20-40℃, dissolved oxygen 0.5-5.0 mg / L, and cultivation time 18-36 h. The bacterial culture that has reached the stationary phase can be directly used as inoculum or prepared into a formulation by adding nutrient solution, preservatives, and protective agents.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) In the emergency treatment method for early warning anomalies in the saline wastewater treatment system of the present invention, the addition of activated sludge, bacterial agent and tetrahydropyrimidine in the oil refinery wastewater treatment system can achieve rapid adaptation of the added sludge and rapid combination of sludge and bacterial agent in different units, which can quickly eliminate the impact risk, realize timely treatment of abnormal system conditions, shorten the system recovery time, and ensure the long-term stable operation of the system. It has strong guiding and reference significance for the comprehensive operation and management of existing wastewater treatment plants.

[0022] (2) This invention uses activated sludge in the oil refinery wastewater treatment system as a resource allocation method to supplement the microbial community in the activated sludge. The organic pollutants in the wastewater can also provide carbon source for the microorganisms in the saline wastewater treatment system, saving resources, reducing operating costs, and achieving quick results with low investment. It can reduce costs and increase efficiency while achieving efficient treatment of pollutants.

[0023] (3) This invention involves adding Halomonas nigrificans, particularly Halomonas nigrificans N2-2, to wastewater treatment plants when they are subjected to shocks. This allows for simultaneous heterotrophic nitrification and aerobic denitrification under high-salt conditions, while also improving the operational stability of saline systems and protecting the degradation activity of other microorganisms, thereby further enhancing wastewater treatment efficiency. This microbial agent exhibits strong adaptability and good compatibility with activated sludge. When wastewater treatment plants experience shocks due to abnormal water quality, the combined use of this microbial agent and activated sludge can significantly shorten the shock recovery time. Detailed Implementation

[0024] The following examples further illustrate the method and effects of the present invention in detail. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following examples.

[0025] Unless otherwise specified, the experimental methods used in the following examples are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following examples can be purchased from biochemical reagent stores.

[0026] In this embodiment of the invention, COD concentration was determined using GB11914-89 "Water Quality - Determination of Chemical Oxygen Demand - Dichromate Method"; ammonia nitrogen concentration was determined using GB7478-87 "Water Quality - Determination of Ammonium - Distillation and Titration Method"; total nitrogen concentration was determined using GB11894-89 "Water Quality - Determination of Total Nitrogen - Ultraviolet Spectrophotometry"; and salt content was determined using HJ / T 51-1999 "Water Quality - Determination of Total Salt Content - Gravimetric Method".

[0027] Example 1: Culture of Halomonas nigrificans N2-2 strain

[0028] Prepare citrate culture medium: sodium citrate 2 g / L, peptone 0.1 g / L, ammonium sulfate 1.0 g / L, potassium nitrate 0.5 g / L, potassium dihydrogen phosphate 0.1 g / L, calcium chloride 5 g / L, sodium chloride 5 g / L, and adjust the pH to 7.5.

[0029] The pure strain of Halomonas nigrificans N2-2 was inoculated into citrate culture medium and cultured in a shaker at 30℃, pH 7.0-7.5, under aerobic conditions for 24 h to obtain activated bacterial solution.

[0030] Inoculate the activated bacterial solution into fresh citrate culture medium at an inoculum volume of 5v%. Incubate for at least 20 hours at 25-30℃, pH 7.0-7.5, and dissolved oxygen 1-3 mg / L. Take samples to detect OD. 660 A bacterial solution with a pH of 0.8 or higher is considered usable.

[0031] Example 2

[0032] The saline wastewater from a certain refining and chemical plant has the following characteristics: COD concentration 800 mg / L, ammonia nitrogen concentration 100 mg / L, total nitrogen concentration 120 mg / L, and salt content 8000 mg / L. A 10L A / O reactor is used to treat this saline wastewater, with a retention time of 8 hours in tank A and 24 hours in tank O. During operation, 200% of the nitrification liquid from tank O is recycled to tank A, and 100% of the activated sludge from the secondary sedimentation tank is recycled to tank A. The operating conditions for tank A are: dissolved oxygen 0.4–0.5 mg / L, pH 7.5–8.0, and temperature 28–30℃; the operating conditions for tank O are: dissolved oxygen 2–3.5 mg / L, pH 7.5–8.0, and temperature 28–30℃. During normal operation, the ammonia nitrogen concentration in the reactor effluent is below 8 mg / L, the total nitrogen concentration is below 40 mg / L, and the COD concentration is below 50 mg / L.

[0033] During operation, sodium chloride was added to the saline wastewater to increase the salt content to 16000 mg / L, and the influent was continuously fed in for 24 hours before restoring the influent quality to normal operation. After three more days of continuous operation, analysis showed that the nitrite nitrogen concentration in the effluent reached 15 mg / L. Activated sludge (MLSS 8000 mg / L) from the secondary sedimentation tank of the company's oil refinery wastewater treatment system was then added to reactor A at a concentration 200 mg / L higher than the replenished sludge concentration. Simultaneously, the bacterial agent from Example 1 was added at a mass-to-volume ratio of 8 mg / L to the wastewater, and tetrahydropyrimidine was added at a mass-to-volume ratio of 10 μg / kg to the bacterial agent. After these additions, the reactor did not discharge sludge, and the water quality was analyzed daily. On the fourth day, no nitrite nitrogen was detected in the system, and the addition of activated sludge, bacterial agent, and tetrahydropyrimidine was stopped. During the emergency treatment and for one month afterward, the system's effluent ammonia nitrogen concentration remained below 8 mg / L, total nitrogen concentration below 40 mg / L, and COD concentration below 50 mg / L.

[0034] Example 3

[0035] The saline wastewater from a certain refining and chemical plant has the following characteristics: COD concentration 400 mg / L, ammonia nitrogen concentration 50 mg / L, total nitrogen concentration 60 mg / L, and salt content 10000 mg / L. A 10L A / O reactor is used to treat this saline wastewater, with a retention time of 8 hours in tank A and 24 hours in tank O. During operation, 200% of the nitrified liquor from tank O is recycled to tank A, and 100% of the activated sludge from the secondary sedimentation tank is recycled to tank A. The operating conditions for tank A are: dissolved oxygen 0.4–0.5 mg / L, pH 7.5–8.0, and temperature 28–30℃; the operating conditions for tank O are: dissolved oxygen 2–3.5 mg / L, pH 7.5–8.0, and temperature 28–30℃. During normal operation, the ammonia nitrogen concentration in the reactor effluent is below 8 mg / L, the total nitrogen concentration is below 40 mg / L, and the COD concentration is below 50 mg / L.

[0036] During operation, the influent flow rate was increased to twice the normal operating rate and continuously supplied for 24 hours before reverting to the normal operating rate. After three days of continuous operation, analysis showed that the nitrite nitrogen concentration in the effluent reached 12 mg / L. Activated sludge (MLSS 8000 mg / L) from the secondary sedimentation tank of the company's oil refinery wastewater treatment system was then added to reactor A at a concentration 100 mg / L higher than the replenished sludge concentration. Simultaneously, the bacterial agent from Example 1 was added at a mass-to-volume ratio of 10 mg / L to the wastewater, and tetrahydropyrimidine was added at a mass-to-volume ratio of 5 μg / kg to the bacterial agent. After these additions, the reactor did not discharge sludge, and the water quality was analyzed daily. On the fourth day, no nitrite nitrogen was detected in the system, and the addition of activated sludge, bacterial agent, and tetrahydropyrimidine was stopped. During the emergency treatment and for one month afterward, the system's effluent ammonia nitrogen concentration remained below 8 mg / L, total nitrogen concentration below 40 mg / L, and COD concentration below 50 mg / L.

[0037] Example 4

[0038] The saline wastewater from a certain refining and chemical plant has the following characteristics: COD concentration 300 mg / L, ammonia nitrogen concentration 80 mg / L, total nitrogen concentration 90 mg / L, and salt content 15000 mg / L. A 10L A / O reactor is used to treat this saline wastewater, with a retention time of 8 hours in tank A and 24 hours in tank O. During operation, 200% of the nitrified liquid from tank O is recycled to tank A, and 100% of the activated sludge from the secondary sedimentation tank is recycled to tank A. The operating conditions for tank A are: dissolved oxygen 0.4–0.5 mg / L, pH 7.5–8.0, and temperature 28–30℃; the operating conditions for tank O are: dissolved oxygen 2–3.5 mg / L, pH 7.5–8.0, and temperature 28–30℃. During normal operation, the effluent ammonia nitrogen concentration is below 8 mg / L, the total nitrogen concentration is below 40 mg / L, and the COD concentration is below 50 mg / L.

[0039] During operation, ammonium sulfate was added to the saline wastewater to raise the influent ammonia nitrogen concentration to 150 mg / L, and this process was continued for 24 hours before the influent quality was restored to normal operating conditions. After three more days of continuous operation, analysis showed that the effluent nitrite nitrogen concentration reached 10 mg / L. Activated sludge (MLSS 8000 mg / L) from the secondary sedimentation tank of the company's oil refinery wastewater treatment system was then added to reactor A at a concentration 500 mg / L higher than the added sludge concentration. Simultaneously, the bacterial agent from Example 1 was added at a mass-to-volume ratio of 8 mg / L to the wastewater, and tetrahydropyrimidine was added at a mass-to-volume ratio of 10 μg / kg to the bacterial agent. After these additions, no sludge was discharged from the reactor, and the water quality was analyzed daily. On the third day of operation, no nitrite nitrogen was detected in the system, and the addition of activated sludge, bacterial agent, and tetrahydropyrimidine was stopped. During the emergency treatment and for one month afterward, the system's effluent ammonia nitrogen concentration remained below 8 mg / L, total nitrogen concentration below 40 mg / L, and COD concentration below 50 mg / L.

[0040] Comparative Example 1

[0041] The saline wastewater from a certain refining and chemical plant has the following characteristics: COD concentration 800 mg / L, ammonia nitrogen concentration 100 mg / L, total nitrogen concentration 120 mg / L, and salt content 8000 mg / L. A 10L A / O reactor is used to treat this saline wastewater, with a retention time of 8 hours in tank A and 24 hours in tank O. During operation, 200% of the nitrification liquid from tank O is recycled to tank A, and 100% of the activated sludge from the secondary sedimentation tank is recycled to tank A. The operating conditions for tank A are: dissolved oxygen 0.4–0.5 mg / L, pH 7.5–8.0, and temperature 28–30℃; the operating conditions for tank O are: dissolved oxygen 2–3.5 mg / L, pH 7.5–8.0, and temperature 28–30℃. During normal operation, the ammonia nitrogen concentration in the reactor effluent is below 8 mg / L, the total nitrogen concentration is below 40 mg / L, and the COD concentration is below 50 mg / L.

[0042] During operation, sodium chloride was added to the saline wastewater to increase the salt content to 16000 mg / L, and the influent was continuously fed in for 24 hours before the influent quality was restored to normal operation. After three more days of continuous operation, analysis showed that the nitrite nitrogen concentration in the effluent reached 15 mg / L. Activated sludge (MLSS 8000 mg / L) from the secondary sedimentation tank of the company's oil refinery wastewater treatment system was then added to reactor A at a rate 200 mg / L higher than the replenished sludge concentration. The reactor was not discharged sludge after the addition, and the water quality was analyzed daily. On the fourth day of operation, the nitrite nitrogen concentration was still above 14 mg / L, so the addition of activated sludge was stopped. The system's effluent concentrations were as high as 37 mg / L for ammonia nitrogen, 61 mg / L for total nitrogen, and 102 mg / L for COD. For the next 15 days, nitrite nitrogen was undetectable. After another 5 days of operation, the system's effluent finally met the standards: ammonia nitrogen concentration below 8 mg / L, total nitrogen concentration below 40 mg / L, and COD concentration below 50 mg / L.

[0043] Comparative Example 2

[0044] The saline wastewater from a certain refining and chemical plant has the following characteristics: COD concentration 800 mg / L, ammonia nitrogen concentration 100 mg / L, total nitrogen concentration 120 mg / L, and salt content 8000 mg / L. A 10L A / O reactor is used to treat this saline wastewater, with a retention time of 8 hours in tank A and 24 hours in tank O. During operation, 200% of the nitrification liquid from tank O is recycled to tank A, and 100% of the activated sludge from the secondary sedimentation tank is recycled to tank A. The operating conditions for tank A are: dissolved oxygen 0.4–0.5 mg / L, pH 7.5–8.0, and temperature 28–30℃; the operating conditions for tank O are: dissolved oxygen 2–3.5 mg / L, pH 7.5–8.0, and temperature 28–30℃. During normal operation, the ammonia nitrogen concentration in the reactor effluent is below 8 mg / L, the total nitrogen concentration is below 40 mg / L, and the COD concentration is below 50 mg / L.

[0045] During operation, sodium chloride was added to the saline wastewater to increase its salt content to 16000 mg / L, and the influent was continuously fed in for 24 hours before restoring the influent quality to normal operation. After three more days of continuous operation, analysis showed that the nitrite nitrogen concentration in the effluent reached 15 mg / L. The bacterial agent from Example 1 was then added to reactor A at a mass-to-volume ratio of 8 mg / L to the wastewater. No sludge was discharged from the reactor after the addition, and the water quality was analyzed daily. On the fourth day, the nitrite nitrogen concentration was still above 13 mg / L, so the addition of the bacterial agent was stopped. The system's effluent concentrations were as high as 35 mg / L for ammonia nitrogen, 54 mg / L for total nitrogen, and 95 mg / L for COD. For the next 14 days, no nitrite nitrogen concentration was detected in the system. After five more days of operation, the system's effluent finally met the standards: ammonia nitrogen concentration below 8 mg / L, total nitrogen concentration below 40 mg / L, and COD concentration below 50 mg / L.

[0046] Comparative Example 3

[0047] The saline wastewater from a certain refining and chemical plant has the following characteristics: COD concentration 800 mg / L, ammonia nitrogen concentration 100 mg / L, total nitrogen concentration 120 mg / L, and salt content 8000 mg / L. A 10L A / O reactor is used to treat this saline wastewater, with a retention time of 8 hours in tank A and 24 hours in tank O. During operation, 200% of the nitrification liquid from tank O is recycled to tank A, and 100% of the activated sludge from the secondary sedimentation tank is recycled to tank A. The operating conditions for tank A are: dissolved oxygen 0.4–0.5 mg / L, pH 7.5–8.0, and temperature 28–30℃; the operating conditions for tank O are: dissolved oxygen 2–3.5 mg / L, pH 7.5–8.0, and temperature 28–30℃. During normal operation, the ammonia nitrogen concentration in the reactor effluent is below 8 mg / L, the total nitrogen concentration is below 40 mg / L, and the COD concentration is below 50 mg / L.

[0048] During operation, sodium chloride was added to the saline wastewater to increase the salt content to 16000 mg / L, and the influent was continuously fed for 24 hours before restoring the influent quality to normal operation. After three days of continuous operation, analysis showed that the nitrite nitrogen concentration in the effluent reached 15 mg / L. Tetrahydropyrimidine, in the same amount as in Example 2, was added to reactor A. No sludge was discharged from the reactor after the addition, and the water quality was analyzed daily. On the fourth day, the nitrite nitrogen concentration was still above 12 mg / L, so the addition of tetrahydropyrimidine was stopped. The system's effluent ammonia nitrogen concentration reached as high as 47 mg / L, total nitrogen concentration reached as high as 67 mg / L, and COD concentration reached as high as 115 mg / L. For the next 18 days, no nitrite nitrogen concentration was detected in the system. After five more days of operation, the system's effluent finally met the standards: ammonia nitrogen concentration below 8 mg / L, total nitrogen concentration below 40 mg / L, and COD concentration below 50 mg / L.

[0049] Comparative Example 4

[0050] The saline wastewater from a certain refining and chemical plant has the following characteristics: COD concentration 800 mg / L, ammonia nitrogen concentration 100 mg / L, total nitrogen concentration 120 mg / L, and salt content 8000 mg / L. A 10L A / O reactor is used to treat this saline wastewater, with a retention time of 8 hours in tank A and 24 hours in tank O. During operation, 200% of the nitrification liquid from tank O is recycled to tank A, and 100% of the activated sludge from the secondary sedimentation tank is recycled to tank A. The operating conditions for tank A are: dissolved oxygen 0.4–0.5 mg / L, pH 7.5–8.0, and temperature 28–30℃; the operating conditions for tank O are: dissolved oxygen 2–3.5 mg / L, pH 7.5–8.0, and temperature 28–30℃. During normal operation, the ammonia nitrogen concentration in the reactor effluent is below 8 mg / L, the total nitrogen concentration is below 40 mg / L, and the COD concentration is below 50 mg / L.

[0051] During operation, sodium chloride was added to the saline wastewater to increase the salt content to 16000 mg / L, and the influent was continuously fed for 24 hours before restoring the influent quality to normal operation. After three days of continuous operation, analysis showed that the nitrite nitrogen concentration in the effluent reached 15 mg / L. At this point, the bacterial agent from Example 1 was added to reactor A at a mass-to-volume ratio of 8 mg / L to the wastewater, along with tetrahydropyrimidine at a mass ratio of 10 μg / kg to the bacterial agent. After the addition, the reactor did not discharge sludge, and the water quality was analyzed daily. On the fourth day, the nitrite nitrogen concentration was still above 10 mg / L, so the addition of bacterial agent and tetrahydropyrimidine was stopped. The system's effluent concentrations were as high as 32 mg / L for ammonia nitrogen, 46 mg / L for total nitrogen, and 85 mg / L for COD. For the next 10 days, nitrite nitrogen was undetectable. After another 5 days of operation, the system's effluent finally met the standards: ammonia nitrogen concentration below 8 mg / L, total nitrogen concentration below 40 mg / L, and COD concentration below 50 mg / L.

[0052] Comparative Example 5

[0053] The saline wastewater from a certain refining and chemical plant has the following characteristics: COD concentration 800 mg / L, ammonia nitrogen concentration 100 mg / L, total nitrogen concentration 120 mg / L, and salt content 8000 mg / L. A 10L A / O reactor is used to treat this saline wastewater, with a retention time of 8 hours in tank A and 24 hours in tank O. During operation, 200% of the nitrification liquid from tank O is recycled to tank A, and 100% of the activated sludge from the secondary sedimentation tank is recycled to tank A. The operating conditions for tank A are: dissolved oxygen 0.4–0.5 mg / L, pH 7.5–8.0, and temperature 28–30℃; the operating conditions for tank O are: dissolved oxygen 2–3.5 mg / L, pH 7.5–8.0, and temperature 28–30℃. During normal operation, the ammonia nitrogen concentration in the reactor effluent is below 8 mg / L, the total nitrogen concentration is below 40 mg / L, and the COD concentration is below 50 mg / L.

[0054] During operation, sodium chloride is added to the saline wastewater to increase the salt content of the wastewater to 16000 mg / L and the wastewater is continuously fed in for 24 hours before the influent water quality is restored to normal operating conditions. After three days of continuous operation, analysis showed that the nitrite nitrogen concentration in the effluent reached 15 mg / L. Activated sludge (MLSS 8000 mg / L) from the secondary sedimentation tank of the company's oil refinery wastewater treatment system was added to reactor A at a concentration 200 mg / L higher than the added sludge concentration. Simultaneously, a bacterial solution of the highly salt-tolerant bacteria (Halomonas nigrificans) GXNYJ-DL-1 (disclosed in CN202011623087.X) was added at a mass-to-volume ratio of 8 mg / L to the wastewater, and tetrahydropyrimidine was added at a mass ratio of 10 μg / kg to the bacterial agent. After these additions, the reactor was not discharged sludge, and the water quality was analyzed daily. On the fourth day, the nitrite nitrogen concentration was still above 10 mg / L, so the addition of bacterial agents and tetrahydropyrimidine was stopped. The system's effluent concentrations were as high as 30 mg / L for ammonia nitrogen, 38 mg / L for total nitrogen, and 78 mg / L for COD. For the next eight days, nitrite nitrogen concentration was undetectable in the system. After running for another 5 days, the system's effluent finally met the standards, namely, ammonia nitrogen concentration less than 8 mg / L, total nitrogen concentration less than 40 mg / L, and COD concentration less than 50 mg / L.

Claims

1. An emergency handling method for early warning anomalies in a saline wastewater treatment system, comprising the following steps: the saline wastewater treatment adopts an anaerobic-aerobic combined process; during operation, when the nitrite nitrogen concentration in the effluent is 5-15 mg / L, activated sludge is added to the influent saline wastewater, and bacterial agents and tetrahydropyrimidine are supplemented; after the addition, the system does not discharge sludge until the nitrite nitrogen concentration is less than 1 mg / L, at which point the addition of activated sludge, bacterial agents, and tetrahydropyrimidine is stopped.

2. The method according to claim 1, characterized in that, The amount of activated sludge to be replenished is based on an increase of 100-500 mg / L in the sludge concentration in the system after addition.

3. The method according to claim 1, characterized in that, The bacterial agent is added at a dosage of 5-10 mg / L, which is the mass-to-volume ratio of the saline wastewater.

4. The method according to claim 1, characterized in that, The amount of tetrahydropyrimidine used is supplemented at a mass ratio of 1-10 μg / kg (preferably 5-10 μg / kg) to the bacterial agent; preferably, tetrahydropyrimidine and the bacterial agent are supplemented simultaneously.

5. The method according to claim 1, characterized in that, The activated sludge contains microorganisms capable of removing COD and nitrogenous pollutants, preferably activated sludge from the secondary sedimentation tank of an oil refinery wastewater biochemical treatment unit; the activated sludge contains MLSS of 4000-9000 mg / L.

6. The method according to claim 1, characterized in that, The saline wastewater has a COD concentration of 200-800 mg / L, an ammonia nitrogen concentration of 50-100 mg / L, a total nitrogen concentration of 50-120 mg / L, and a salt content of 5000-20000 mg / L.

7. The method according to claim 1, characterized in that, During operation, the system effluent ammonia nitrogen concentration is less than 8 mg / L, total nitrogen concentration is less than 40 mg / L, and COD concentration is less than 50 mg / L.

8. The method according to claim 1, characterized in that, The saline wastewater adopts an anaerobic-aerobic combined process, which includes: the saline wastewater to be treated first enters tank A for anaerobic treatment and then enters tank O for aerobic treatment. After A / O treatment, the wastewater enters the subsequent sedimentation tank and is discharged after passing the test. Preferably, a nitrification liquid return pipeline is set between tank O and tank A, and a sludge return pipeline is set between the secondary sedimentation tank and tank A. Preferably, the operating conditions for tank A are: dissolved oxygen 0.1–1.0 mg / L, preferably 0.2–0.5 mg / L, pH 7.0–8.5, and temperature 20–40°C; the operating conditions for tank O are: dissolved oxygen 1–5 mg / L, preferably 2–4 mg / L, pH 7.0–8.5, and temperature 20–40°C.

9. The method according to claim 1, characterized in that, The aforementioned anomaly refers to an increase in the concentration of nitrite in the effluent caused by at least one of water quality fluctuations, water quantity fluctuations, and salinity.

10. The method according to claim 1, characterized in that, The bacterial agent is Halomonas nigrificans N2-2, which was deposited at the China General Microbiological Culture Collection Center on March 18, 2024, with accession number CGMCC No. 30065.

11. The method according to claim 1, characterized in that, The Halomonas nigrificans N2-2 has a rod-shaped morphology, with milky white, opaque colonies, regular edges, a raised surface, no halo, and a diameter of 1-2 mm. Its biological characteristics are: Gram-negative, catalase-positive, oxidase-positive, and urease-positive; it is a heterotrophic nitrifying bacterium that can utilize a variety of carbon sources, preferably citrate.