Method for removing nitrate nitrogen in wastewater with different salinity based on FBBR process and application

Abstract

The invention discloses a method for removing nitrate nitrogen in wastewater with different salinity based on an FBBR technology and application, the method is characterized in that Marinobacter maritimus is added into the wastewater with different salinity, the bacterium can resist the influence of high-concentration salinity on the growth of the bacterium, the effect of stably removing nitrate nitrogen in the wastewater is achieved, and the nitrate nitrogen in the wastewater can be effectively removed. Therefore, the defect that the growth and metabolism of microorganisms are inhibited under a high-salt condition in a biological denitrification process is overcome, and a new microorganism choice is provided for the development of the biological denitrification process.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and in particular to a method and application of removing nitrate nitrogen in wastewater with different salinities based on a FBBR process. Background Art

[0002] With the acceleration of industrialization, the environmental load caused by industrial wastewater discharge has increased exponentially, seriously endangering the environment and human health. Some industrial wastewaters contain a large amount of inorganic salt ions, such as aquaculture wastewater, desulfurization wastewater, vegetable pickling wastewater, textile wastewater, oil-containing wastewater, etc. The discharge of untreated salt-containing wastewater will cause multi-dimensional ecological risks.

[0003] High-salt wastewater is often accompanied by significant nitrogen pollution, forming a "salt-nitrogen composite pollution" system with a synergistic inhibitory effect. From the perspective of environmental chemistry, nitrate, as a thermodynamically stable nitrogen-containing compound, exists stably in the environment and can migrate rapidly. Untreated nitrate wastewater entering the environment will seriously threaten the ecological environment and human health. Nitrates are converted into nitrites through biological transformation, and accumulation through the food chain can cause public health risks such as methemoglobinemia. Therefore, the development of efficient and stable nitrate nitrogen removal technology in different salinity environments has become a scientific problem that needs to be overcome urgently in the field of environmental engineering.

[0004] There are three types of wastewater denitrification technologies: physical, chemical, and biological. Compared with physical and chemical methods, biological methods have the advantages of high efficiency, low energy consumption, low cost, and easy implementation. They are currently widely used in biological denitrification processes. However, high concentrations of salt ions in wastewater have a significant effect on biological denitrification. When microorganisms are in a high-salt environment, high concentrations of salt will cause excessive water loss in microbial cells and reduce the activity of metabolic enzymes, thereby inhibiting microbial growth and metabolism, and even causing cell death. Studies have reported that even lower salt concentrations can have a negative impact on microorganisms in activated sludge. In the process of denitrification of high-salt wastewater, the denitrification ability of most denitrifying bacteria is inhibited by high salinity. Some studies have demonstrated the feasibility of using salt-tolerant biomass to treat saline wastewater, but the system can only maintain stable performance within a lower salinity range. However, many industrial wastewaters have high salt ion concentrations and large fluctuations in ion concentrations. When the salinity exceeds 20 g / L, microorganisms can be strongly inhibited.

[0005] Therefore, finding a microorganism that can be used to treat nitrate nitrogen in wastewater with higher salinity is of great significance to the development of biological denitrification technology. Summary of the invention

[0006] In order to overcome the above-mentioned defects and shortcomings in the prior art, the present invention provides a method and application of removing nitrate nitrogen in wastewater with different salinities based on the FBBR process.

[0007] The first object of the present invention is to provide Marinobacter maritimus Application in removing nitrate nitrogen from saline wastewater.

[0008] A second object of the present invention is to provide Marinobacter maritimus Application in the preparation of products for removing nitrate nitrogen from saline wastewater.

[0009] The third object of the present invention is to provide a method for removing nitrate nitrogen from saline wastewater.

[0010] The present invention claims the following: Marinobacter maritimus In the application of removing nitrate nitrogen from saline wastewater, the Marinobacter maritime It is deposited in the China Marine Microbiological Culture Collection Center with the deposit number MCCC 1A04163.

[0011] Marinobacter maritimus Application of the invention in preparing a product for removing nitrate nitrogen from saline wastewater, Marinobacter maritimus It is deposited in the China Marine Microbiological Culture Collection Center with the deposit number MCCC1A04163.

[0012] Preferably, the salinity of the saline wastewater is 80-120 g / L.

[0013] As an practicable manner, the wastewater includes pharmaceutical wastewater, domestic sewage, aquaculture wastewater, pickling wastewater and / or industrial wastewater.

[0014] A method for removing nitrate nitrogen in saline wastewater, adding Marinobacter maritime , Marinobacter maritimus It is deposited in the China Marine Microbiological Culture Collection Center with the deposit number MCCC 1A04163.

[0015] Preferably, the salinity of the saline wastewater is 80-120 g / L.

[0016] Preferably, the removal of nitrate nitrogen from saline wastewater is carried out using a biofilm reactor.

[0017] More preferably, the biofilm reactor is a fixed bed biofilm reactor.

[0018] As an practicable manner, the wastewater includes pharmaceutical wastewater, domestic sewage, aquaculture wastewater, pickling wastewater and / or industrial wastewater.

[0019] Preferably, the Marinobacter maritimus The inoculation rate is 1-3%.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a method and application of removing nitrate nitrogen from wastewater with different salinities based on FBBR process. The method comprises adding Marinobacter maritimus . Marinobacter maritime It is deposited in the China Marine Microbial Culture Collection Center, No. 178, University Road, Xiamen, Fujian Province, with the deposit number MCCC 1A04163. The bacteria can resist the influence of high concentration of salt on the growth of bacteria themselves, and achieve the effect of stable removal of nitrate nitrogen in wastewater, thus overcoming the deficiency of microorganisms being inhibited from growth and metabolism under high salt conditions in biological denitrification process, and providing a new microbial choice for the development of biological denitrification process. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Figure 2 is a diagram of the experimental setup of a fixed bed biofilm reactor (FBBR). DETAILED DESCRIPTION

[0022] The present invention is further described below with reference to specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0023] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0024] Marinobacter maritimus It is deposited in the China Marine Microbiological Culture Collection Center with the deposit number MCCC 1A04163.

[0025] The above-mentioned strains were purchased directly from the China Marine Microbial Culture Collection Administration Center, and their preservation information can be directly obtained through the China Marine Microbial Culture Collection Administration Center.

[0026] M2 medium: CH3COONa 5 g, peptone 0.5 g, yeast extract 0.5 g, glucose 0.5 g, sucrose 0.5 g, sodium citrate 0.05 g, DL-malic acid 0.05 g, NH4NO3 1.0 g, NH4Cl 0.2 g, KH2PO4 0.5 g, filtered seawater 1000 mL, pH 7.6, sterilized at 121°C for 20 min.

[0027] Example 1 Construction and operation of a fixed bed biofilm reactor (FBBR) 1. Experimental Methods 1. Construction of FBBR reactor The experimental device of FBBR reactor is as follows Figure 1As shown, its effective volume is 4.5 L, with laboratory water as inlet, and the operation cycle is 174 days. The FBBR reactor contains 260 K3 high-density polyethylene fillers (Jiangsu Yulong Environmental Protection Co., Ltd.), and the filling height ratio is 60%.

[0028] Biofilm formation: The FBBR reactor was inoculated with sludge from a wastewater treatment plant in Zhuhai. The filler and sludge were mixed and then exposed for 36 hours. The sludge was discarded to construct the initial microbial community. The FBBR reactor was operated in a continuous flow mode with a hydraulic retention time (HRT) of 12 hours. The influent of the FBBR reactor contained nitrate (NO3 - -N) 200 mg / L (in terms of N) and COD 1000 mg / L. The specific influent composition is shown in Table 1, and the composition of trace elements is shown in Table 2.

[0029] Table 1 Reactor influent composition

[0030] Table 2 Trace element composition

[0031] 2. Operation of FBBR reactor After the FBBR reactor was started, NaCl was added to the influent and its concentration was gradually increased to analyze the long-term effect of different salinities on the denitrification performance of the FBBR reactor. The system was divided into three stages, namely stage I (0-49 days, freshwater stage, 0 g / L NaCl), stage II (50-98 days, medium salt stage, 50 g / L NaCl), and stage III (99-174 days, high salt stage, 100 g / L NaCl), with a total operation of 174 days.

[0032] The effluent from the FBBR reactor was sampled regularly (every 2 days) and immediately after the effluent samples were obtained, 0.45 μ The supernatant was obtained by filtration through a polyethylene filter membrane and used for systematic monitoring of the FBBR reactor performance. The ammonia nitrogen (NH4 + -N), nitrite (NO2 - -N), nitrate (NO3 - -N) and total nitrogen (TN) concentrations.

[0033] 2. Experimental Results Without adding NaCl (stage I), the system showed stable denitrification performance. -The -N removal rate was maintained at about 99.8%, and the effluent TN concentration was 3.6 ± 2.3 mg / L (TN removal rate>95%). This shows that the system can maintain a high denitrification performance under freshwater conditions.

[0034] When the inlet salinity increases to the medium salt range (Phase II), the system performance deteriorates significantly. The increase in salinity causes the system outlet water to have NO3 - -N concentration increased to 119.8 mg / L, NO3 - -N removal rate dropped significantly from 100% to 40.1%. After 21 days of functional recovery, the system achieved performance recovery, and NO3 - The -N effluent concentration decreased from 78.2 mg / L to 5.0 mg / L, and the corresponding removal rate reached 97.5%.

[0035] The salinity stress in the high-salinity stage (stage III) induces a more persistent metabolic inhibition effect. Salinity jump leads to NO3 - -N removal rate dropped to 35.5%, and the effluent concentration increased to 129.0 mg / L. After 38 days of acclimatization, the system recovered its function, and NO3 - -N removal rate rose to 98.5%, and the effluent concentration was stabilized below 3.0 mg / L. Chemometric analysis showed that there was no significant difference in the total inorganic nitrogen removal rate at each stage ( P >0.05), and the removal efficiency was maintained above 90%.

[0036] Example 2 Screening of salt-tolerant denitrification strains 1. Experimental Methods Microbial samples were taken for DNA sequencing on days 0, 10, 20, 30, 40, 50, 55, 60, 65, 70, 75, 82, 90, 99, 105, 113, 121, 129, 137, 145, 153, 161, 169, and 174 of the operation of the FBBR reactor of Example 1. The sampling method was as follows: the biofilm was brushed into a 50 mL centrifuge tube with a brush, and the biofilm sample was obtained after centrifugation (4°C, 12000 rpm, 15 min).

[0037] Genomic DNA of the samples was extracted using the OMEGA soil DNA kit, and the V3-V4 hypervariable region of the bacterial 16S rRNA gene was amplified by PCR using primers 338F (5'-ACTCCTACGGGAGGCAGCA-3', SEQ ID NO: 1) and 806R (5'-GGACTACHVGGGTWTCTAAT-3', SEQ ID NO: 2), and the PCR products were quantified using a NanoDrop spectrophotometer. The purified amplicon library was sequenced (2 × 250 bp) by Shanghai Paisono Biotechnology Co., Ltd. (Shanghai, China) according to the standard operating procedures of the Illumina NovaSeq platform.

[0038] 2. Experimental Results The sequencing results showed that Marinobacter maritimus The abundance in stage III is higher, and its abundance increases with the increase of salinity. Marinobacter maritimus The abundance in stage II increased by about 9.8 times, and the abundance in stage III increased by about 1.6 times compared with stage II, indicating that Marinobacter maritime May be able to tolerate high-salinity environments and perform denitrification functions.

[0039] Example 3 Marinobacter maritimus Denitrification performance 1. Experimental Methods Purchased from China Marine Microbial Culture Collection Center Marinobacter maritimus strain (deposit number MCCC 1A04163), Marinobacter maritimus The seed solution was inoculated into M2 medium and cultured at 25°C and 130 rpm for 48 h to obtain seed solution, which was then inoculated into M2 medium for expansion culture at 25°C to obtain Marinobacter maritimus Bacterial liquid.

[0040] Take 5 mL of bacterial solution, centrifuge at 4000 rpm for 10 min at 4°C, discard the supernatant, rinse the precipitate twice with phosphate buffer solution (pH 7.4), centrifuge at 4000 rpm for 10 min at 4°C, and take the precipitate. Inoculate the precipitate into a triangular flask containing 100 mL of simulated sewage, respectively, and set the simulated sewage to contain 200 mg / L NO3 - -N and 2000 mg / L COD (with sodium acetate as carbon source), 400 mg / L NO3 - -N and 4000 mg / L COD (with sodium acetate as the carbon source), and the NaCl concentration in the simulated sewage was set to 80, 100, and 120 g / L, respectively.

[0041] The flask was placed in a shaking incubator at 25°C and 130 r / min for shaking culture. Samples were taken after 24 h and centrifuged at 10,000 rpm for 10 min. The NO3 in the supernatant was determined by UV spectrophotometry. - -N concentration.

[0042] 2. Experimental Results The results are shown in Table 3. Marinobacter maritimus Under different salinity conditions, 200 mg / L and 400 mg / L NO3 - -N have good removal ability, indicating Marinobacter maritimus Able to tolerate higher salinity and exhibit superior denitrification capabilities.

[0043] Table 3 Marinobacter maritimus Nitrate degradation capacity under different salinity conditions

[0044] Example 4 Marinobacter maritimus Denitrification effect in FBBR reactor 1. Experimental Methods according to Figure 1 The FBBR reactor was constructed with an effective volume of 4.5 L and laboratory water as the inlet water. The FBBR reactor contained 260 K3 high-density polyethylene fillers (Jiangsu Yulong Environmental Protection Co., Ltd.) with a filling height ratio of 60%.

[0045] Biofilm formation: The FBBR reactor was inoculated with sludge from a wastewater treatment plant in Zhuhai. The filler and sludge were mixed and then exposed for 36 h, and the sludge was discarded. The FBBR reactor was operated in a continuous flow mode, and the hydraulic retention time (HRT) was controlled to be 12 h. The nitrate (NO3 - -N) 200 mg / L (in terms of N) and COD 1000 mg / L (the specific influent composition is in accordance with Table 1 in Example 1), nitrate (NO3 - -N) 500 mg / L (in terms of N) and COD 2500 mg / L (the specific influent composition is as shown in Table 4), nitrate (NO3 - -N) 800 mg / L (in terms of N) and COD 4000 mg / L (the specific influent composition is as per Table 5).

[0046] Table 4 500 mg / L nitrate reactor influent composition

[0047] Table 5 800 mg / L nitrate reactor influent composition

[0048] The biofilm was allowed to grow until the FBBR reactor system was stable, so that the biofilm biomass of the FBBR reactor was maintained at about 2000-2500 mg / L, and the NO3 - The -N removal rate reached over 95% (after about 30 days of operation).

[0049] After the FBBR reactor was running stably, the FBBR reactor was randomly divided into an experimental group and a control group, and the following treatments were performed respectively: Experimental group: Marinobacter maritimus (Deposit number: MCCC 1A04163) was inoculated into M2 medium and cultured at 25°C and 130 rpm for 48 h to obtain seed solution, which was then inoculated into M2 medium for expansion culture at 25°C. When the OD600 value was 0.6-0.8, the Marinobacter maritimus Bacterial liquid. Marinobacter maritimus The bacterial solution was inoculated into the FBBR reactor at an inoculation rate of 1% of the volume of water treated per hour; Control group: no access Marinobacter maritimus Bacterial liquid; After different treatments, the NaCl concentration of the influent was controlled at 80 g / L, 100 g / L, and 120 g / L, respectively, and the reactors at each salinity continued to operate for 48 h.

[0050] The effluent from the FBBR reactor was sampled every 12 h, and the effluent samples were immediately μ The supernatant was obtained by filtration through a polyethylene filter membrane and used to systematically monitor the performance of FBBR reactors at different salinities. The nitrate (NO3 - -N) concentration.

[0051] 2. Experimental Results The results are shown in Table 6. When the NaCl concentration of the influent water of the FBBR reactor in the experimental group was 80-120 g / L, the NO3 - -N removal rates were all above 90%, compared to the NO3 - The removal capacity of -N was significantly increased.

[0052] The above results show that based on the FBBR process, additional Marinobacter maritimus It can improve the removal efficiency of nitrate nitrogen in wastewater under high-salinity conditions, indicating Marinobacter maritimus It has both salt tolerance and good denitrification performance, and can be used for nitrate nitrogen treatment in high-salinity wastewater.

[0053] Table 6 FBBR reactor Marinobacter maritimus Ability to degrade nitrate nitrogen

[0054] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. Marinobacter maritimus The application of removing nitrate nitrogen from saline wastewater is characterized by: Said Marinobacter maritimus It is deposited in the China Marine Microbiological Culture Collection Center with the deposit number MCCC1A04163.

2. Marinobacter maritimus The application of the method in preparing a product for removing nitrate nitrogen from saline wastewater is characterized in that: Said Marinobacter maritimus It is deposited in the China Marine Microbiological Culture Collection Center with the deposit number MCCC 1A04163.

3. The use according to claim 1 or 2, characterized in that: The salinity of the saline wastewater is 80-120 g / L.

4. The use according to claim 1 or 2, characterized in that: The wastewater includes pharmaceutical wastewater, domestic sewage, aquaculture wastewater, pickling wastewater and / or industrial wastewater.

5. A method for removing nitrate nitrogen from saline wastewater, characterized in that: Adding salty wastewater Marinobacter maritimus , Marinobacter maritimus It is deposited in the China Marine Microbiological Culture Collection Center with the deposit number MCCC 1A04163.

6. The method according to claim 5, characterized in that The salinity of the saline wastewater is 80-120 g / L.

7. The method according to claim 5, characterized in that The removal of nitrate nitrogen from saline wastewater is performed by using a biofilm reactor.

8. The method according to claim 7, characterized in that The biofilm reactor is a fixed bed biofilm reactor.

9. The method according to claim 5, characterized in that The wastewater includes pharmaceutical wastewater, domestic sewage, aquaculture wastewater, pickling wastewater and / or industrial wastewater.

10. The method according to claim 5, characterized in that Said Marinobacter maritimus The inoculation rate is 1-3%.

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