Method for treating multiple pollutants in ship waste gas washing waste liquid by adding exogenous C14-HSL

Abstract

The invention discloses a method for treating multiple pollutants in ship waste gas washing waste liquid by adding exogenous C14-HSL. The method comprises the following steps: 1, placing aerobic sludge in a completely mixed anaerobic stirred reactor for domestication, and completing domestication of glycerine sulfite mixotrophic denitrification activated sludge in a manner of intermittent water feeding and continuous water feeding in sequence; and 2, adding C14-HSL into the completely mixed anaerobic stirred reactor in stages, and regulating to form a stable microbial community composition so as to promote synchronous degradation of multiple pollutants. The comprehensive treatment of the ship waste gas denitration wastewater and the ship organic wastewater has higher environmental and economic benefits.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a method for treating multiple pollutants in ship exhaust gas scrubbing wastewater by adding exogenous N-tetradecanoyl-L-homoserine lactone (C14-HSL). Background Technology

[0002] The rapid development of maritime trade and the shipping industry has led to ships emitting large amounts of CO2 and SO2. x and NO x Ship exhaust gas is currently mainly treated through wet scrubbing. One method, based on a high-gravity reactor, treats CO2, SO2, and NO from the exhaust gas as a combined target. NaOH, C3H8O3, and NaClO are selected as absorbent, additive, and oxidant, respectively, to construct chemical absorption and oxidation absorption reaction units for exhaust gas treatment. The resulting scrubbing wastewater contains C3H3O3 and SO42-. 2- SO3 2- And a large amount of NO3 - The IMO stipulates that ships using wet desulfurization technology cannot directly discharge the wastewater after washing into the ocean; they must dispose of the SO3... 2- Oxidized into environmentally friendly and stable SO4 2- However, wastewater must meet certain standards before it can be discharged into the sea. With current technology, ship washing wastewater can only be collected and discharged onto land for treatment, which presents a problem of insufficient space on ships. Therefore, in-situ treatment of sulfites and nitrates on ships has important practical significance. Summary of the Invention

[0003] This invention addresses the aforementioned problems by researching and designing a method for treating multiple pollutants in ship exhaust gas scrubbing wastewater by adding exogenous C14-HSL. The technical means employed in this invention are as follows: A method for treating multiple pollutants in ship exhaust gas scrubbing wastewater by adding exogenous C14-HSL includes the following steps: S1: Glycerylsulfite co-culture denitrification sludge acclimation stage: The aerobic sludge is placed in a completely mixed anaerobic stirred reactor, using an intermittent influent method, with a hydraulic retention time of 24-72 hours. The reactor temperature is set at 20-40℃, and the reactor is operated for 15-20 days. Glyceryl sulfite and SO3 are introduced into the reactor. 2- NO3 - The acclimation water, wherein SO3 in the acclimation water 2- S content is 500-700 mg / L, glycerol content is 200-300 mg / L, NO3 content is... - The concentration of nitrogen (N) is 150-200 mg / L; when the TOC removal rate increases to over 75%, SO3... 2-Removal rate increased to over 71%, NO3 - After the removal rate is increased to over 80%, the feed water is switched to continuous flow, the hydraulic retention time is 12-48 hours, and the glycerol concentration is adjusted to 300-400 mg / L (calculated as C); when NO3... - The removal rate remained at (80±8)%, SO3 2- The removal rate remained at (76.8±7)%, S 2- The formation rate remained at (2±0.2)%, SO4 2- The formation rate remained at (60±6)%, and the acclimation of glycerol sulfite-ditrophic denitrifying sludge was completed. S2: C14-HSL addition stage: The ship exhaust gas washing waste liquid is treated using a fully mixed anaerobic stirred reactor containing sludge acclimated in step S1. A continuous water inlet method is adopted, and the temperature inside the reactor is 20-40℃. C14-HSL is added to the reactor in three stages, each stage lasting 20-30 days. The concentration of C14-HSL in the three stages increases in the range of 5-10 nmol / L.

[0004] Furthermore, the waste liquid from the ship exhaust gas washing process is generated by treating ship exhaust gas using a supergravity device, wherein NaOH, C3H8O3, and NaClO are selected as absorbent, additive, and oxidant, respectively, for the supergravity device.

[0005] Furthermore, in step S1, C14-HSL is not added; in step S2, SO3 in the influent of the completely mixed anaerobic stirred reactor 2- The concentration of sulfur (S) is 500-700 mg / L, the concentration of glycerol (C) is 300-400 mg / L, and the concentration of NO3 is... - The nitrogen concentration is 150-200 mg / L, and the sulfur concentration in the effluent is monitored every 12-36 hours. 2- SO4 2- SO3 2- NO3 - and TOC concentration.

[0006] Further, in step S1, the stirring speed in the reactor is 15-20 r / min; in step S2, the stirring speed in the reactor is 20-30 r / min.

[0007] Furthermore, the acclimation water is artificially prepared water or waste liquid from ship exhaust gas washing. When the acclimation water is artificially prepared, its components are fresh water, glycerol, and SO3. 2- NO3 - .

[0008] Furthermore, the inoculation concentration of aerobic sludge is 20-40 g MLVSS / L.

[0009] Furthermore, in step S1, the dominant bacterial genera in the acclimated activated sludge include Desulfomicrobium , Brevefilum , UBA6170 , Stutzerimonas , Thiobacillus and Desulfatitalea .

[0010] Compared with existing technologies, the method for treating multiple pollutants in ship exhaust gas scrubbing wastewater by adding exogenous C14-HSL described in this invention has the following advantages: (1) The utilization efficiency of carbon source has been optimized, which is conducive to the efficient removal of multiple pollutants by using quorum sensing technology to directionally regulate the process. This solves the problem of low nitrogen removal efficiency in the facultative nitrification process. (2) Introducing the quorum sensing signal molecule C14-HSL into the glycerol sulfite dual-trophic denitrification system can specifically induce microorganisms to complete the desulfurization and denitrification reaction, thus shortening the waste liquid treatment cycle. (3) The reactor is a continuous anaerobic stirred reactor, which can carry out in-situ integrated treatment of S, N and C pollutants on the ship, solving the problem that the ship has insufficient space and can only discharge them to land for treatment. Attached Figure Description

[0011] Figure 1 SO3 in the glycerol sulfite co-trophic denitrification acclimatization stage of this invention embodiment 2- NO3 - TOC removal rate and SO4 2- S 2- S 0 The relationship between generation rate and processing days.

[0012] Figure 2 In this embodiment of the invention, SO3 is added during the C14-HSL stage. 2- NO3 - TOC removal rate and SO4 2- S 2- S 0 The relationship between generation rate and processing days.

[0013] Figure 3 This is a diagram showing the distribution pattern of functional bacteria in the system according to their genus in this embodiment of the invention. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] Step 1, Acclimation stage of glycerol sulfite co-culture denitrification sludge: Low-activity aerobic sludge was acclimated in a completely mixed anaerobic stirred reactor. The acclimation method was as follows: the low-activity aerobic sludge was placed in the completely mixed anaerobic stirred reactor using an intermittent influent method. The reactor temperature was set at 30±0.5℃, and the stirring speed was 15-20 r / min. The reactor was run for 17 days. 5L of sludge was placed in the reactor, and a mixture of glycerol and SO3 was introduced into the reactor. 2- NO3 - The mixed wastewater contains SO4 in its influent. 2- The concentration, calculated as S, is 500-700 mg / L; the concentration of glycerol, calculated as C, is 200-300 mg / L; and the concentration of NO3 is... - The nitrogen concentration was 150-200 mg / L. The TOC removal rate gradually increased from 13% to 75%, and SO3... 2- The removal rate gradually increased from 56% to 71% for NO3. - After gradually increasing the removal rate from 50% to 80%, the system was switched to continuous influent, and the glycerol concentration was adjusted to 300-400 mg / L (calculated as C) and NO3. - The removal rate is relatively stable, remaining at around 80% for SO3. 2- The removal rate increased to 76.8% and remained stable, higher than the average of the intermittent acclimatization phase, S 2- The formation rate fluctuates around 2%, SO4 2- When the formation rate gradually increases in the later stage and remains at around 60%, the acclimation of glycerol sulfite-containing denitrifying sludge is completed, and the first step of the system is successfully started.

[0016] Step 2, C14-HSL addition stage: After the system's initial startup is successful, the C14-HSL concentration is gradually increased in the reactor in three stages: 5, 7.5, and 10 nmol / L. The reactor is fed continuously, with the temperature set at 30 ± 0.5℃ and the stirring speed at 20-30 r / min. The reactor contains glycerol and SO3. 2- NO3 - The mixed wastewater contains SO3 in its influent. 2-The concentration, calculated as S, is 500-700 mg / L; glycerol, calculated as C, is 300-400 mg / L; NO3... - The nitrogen concentration is 150-200 mg / L, and sulfur in the water is detected every 24 hours. 2- SO4 2- SO3 2- NO3 - With TOC concentration, the second step of the system startup was successful.

[0017] The low-activity aerobic sludge acclimated in this embodiment was taken from the residual activated sludge in the secondary sedimentation tank of a municipal wastewater treatment plant.

[0018] In this embodiment, the ship wastewater treated originates from ship exhaust gas and is processed using a high-gravity device. NaOH, C3H8O3, and NaClO are selected as absorbent, additive, and oxidant, respectively, to construct a chemical absorption and oxidation absorption reaction unit. The resulting substances include C3H8O3 and SO42-. 2- SO3 2- And a large amount of NO3 - Ship exhaust gas scrubbing wastewater. The inoculum concentration of low-activity aerobic sludge is 20-40 g MLVSS / L.

[0019] This implementation plan addresses the S in the treated wastewater. 0 S 2- SO4 2- SO3 2- NO3 - The concentration of TOC was measured. Step 1: The entire operation phase of the device lasted 62 days, including a 17-day intermittent water intake phase with a hydraulic retention time of 48 hours, a 20-day continuous water intake phase with a hydraulic retention time of 48 hours, and a 25-day continuous water intake phase with a hydraulic retention time of 24 hours. Results are shown below. Figure 1 , Figure 1 SO3 during the acclimatization stage of glycerol sulfite-dihydro-denitrification 2- NO3 - Removal rate and SO4 2- S 2- S 0 The graph shows the relationship between NO3 generation rate and treatment days. Phase A represents the intermittent water intake phase with a hydraulic retention time of 48 hours; Phase B represents the continuous water intake phase with a hydraulic retention time of 48 hours; and Phase C represents the continuous water intake phase with a hydraulic retention time of 24 hours. In the integrated device, NO3... - The removal rate remained at around 80%; SO3 2- The removal rate increased to 76.8% and remained stable; S 2- The formation rate fluctuates around 2%, SO4 2-The formation rate remained at around 60%. These results indicate that the glycerol-sulfite co-trophic denitrification acclimatization stage in step one has been successfully initiated.

[0020] Step Two: The entire operation of the device is divided into three stages, X1-X4, each lasting 20-30 days. Results are shown below. Figure 2 , Figure 2 SO3 2- NO3 - TOC removal rate and SO4 2- S 2- S 0 The graph shows the relationship between the generation rate and the number of treatment days. The treatment effect is stable during operation, and the reaction system has strong resistance to shock loads.

[0021] according to Figure 3 As shown, in order to gain a deeper understanding of the metabolic functions of the system's microorganisms, the composition of the microbial community at the genus level in the reactor was analyzed. The three stages of device operation, R1-R4, were used to analyze in detail the distribution of functional bacteria in the device under different number of days.

[0022] During stages R1-R4, there were 15 dominant bacterial genera, namely the desulfurizing microorganisms. Desulfomicrobium, Short-filamentous fungi Brevefilum, UBA6170, Pseudomonas schrenckii Stutzerimonas, Thiobacillus Thiobacillus, Desulfurized bacilli Desulfatitalea, Taureella Thauera, genus *Trichophyton* Trichococcus, genus Mesophytes Mesolinea, JAAYLU01, Desulfuric Vibrio Desulfolutivibrio, JAABTL01, Desulfurized Leaf Fungus Desulfobulbus, Desulfurizing Corynebacterium Desulfotignum, genus *Paraerythromycetes* Pararhodobacter.

[0023] In the R1 phase, without the addition of exogenous C14-HSL, the system is in an inefficient metabolic state, with high levels of TOC and NO3. - The removal rate was only about 75%-80%. Upon entering the R2 stage, the addition of 5 nmol / L C14-HSL preferentially triggered [removal / removal]. Desulfomicrobium The LuxR-type receptor. As a typical core genus of sulfur-metabolizing bacteria, its increased proportion directly enhances the activity of the sulfite reductase system, thereby driving SO3. 2- The removal rate has steadily improved. Meanwhile, Thauera Begin to show with Brevefilum and UBA6170 Initial coordination, this interspecific cooperation prioritized and accelerated S 2- Oxidation to intermediate state S 0However, a complete oxidation chain has not yet been formed. The accumulation of these intermediate products is not a fault, but rather a transition of the system from a chaotic spontaneous state to an ordered sulfur conversion path driven by QS.

[0024] In stage R3, as C14-HSL increased to 7.5 nmol / L, a dramatic process of natural selection occurred within the community. This concentration of C14-HSL precisely matches... Desulfomicrobium The affinity of LuxR receptors induces explosive growth, thereby gaining an absolute advantage in resource competition. Stutzerimonas , Thiobacillus and Trichococcus Due to their low response efficiency at specific signal thresholds, the survival space of bacteria in the genus *Ispermia* is significantly compressed, leading to a substantial reduction in their relative abundance. This community structure greatly weakens the sulfur oxidation pathway, while the sulfur reduction pathway becomes dominant, resulting in a decrease in sulfur concentration in the system. 2- Start accumulating.

[0025] In the R4 phase, the intense metabolic burden generated by high concentrations of C14-HSL forces the community to redistribute resources, inducing... Desulfomicrobium Collaboration Desulfolutivibrio and JAAYLU01 The bacteria significantly activated SO4. 2- SO3 2- Restore path, causing S 2- It accumulated and utilized most of the electrons, not only suppressing Thiobacillus The activity of sulfur-oxidizing bacteria leads to the production of SO3. 2- The removal and sulfur oxidation pathways were blocked, and severe competition for electron acceptors arose due to the excessive occupation of reducing power by the core microbial community. Mesolinea The dense biofilm formed by these bacteria increases mass transfer resistance, ultimately forcing the system to sacrifice heterotrophic degradation efficiency to maintain structural homeostasis under high pressure, resulting in a significant decrease in TOC removal rate. However, at high C14-HSL concentrations, the microbial community tends to prioritize metabolic processes with the highest energy gain. The free energy released by denitrification is much higher than that of sulfate reduction, so it is preferentially used to maintain denitrification to cope with the metabolic burden brought by the signaling process. Therefore, NO3... - The removal rate remains consistently high and maintains extremely high stability.

[0026] Throughout the entire process, C14-HSL not only regulated the abundance of dominant bacteria but also established an efficient electron transport network across the entire community, enabling S... 2- The formation rate was consistently kept at an extremely low level, avoiding the accumulation of toxicity. This evolutionary logic, dominated by signaling molecules and expanding from a single genus to the synergistic effect of the entire community, ultimately achieved near-complete removal and efficient coupling transformation of sulfur, nitrogen, and carbon pollutants in the biofilm system.

[0027] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for treating multiple pollutants in ship exhaust gas scrubbing wastewater by adding exogenous C14-HSL, characterized in that, Includes the following steps: S1: Glycerylsulfite co-culture denitrification sludge acclimation stage: The aerobic sludge is placed in a completely mixed anaerobic stirred reactor, using an intermittent influent method, with a hydraulic retention time of 24-72 hours. The reactor temperature is set at 20-40℃, and the reactor is operated for 15-20 days. Glyceryl sulfite and SO3 are introduced into the reactor. 2- NO3 - The acclimation water, wherein SO3 in the acclimation water 2- S content is 500-700 mg / L, glycerol content is 200-300 mg / L, NO3 content is... - The concentration of nitrogen (N) is 150-200 mg / L; when the TOC removal rate increases to over 75%, SO3... 2- Removal rate increased to over 71%, NO3 - After the removal rate is increased to over 80%, the feed water is switched to continuous flow, the hydraulic retention time is 12-48 hours, and the glycerol concentration is adjusted to 300-400 mg / L (calculated as C); when NO3... - The removal rate remained at (80±8)%, SO3 2- The removal rate remained at (76.8±7)%, S 2- The formation rate remained at (2±0.2)%, SO4 2- The formation rate remained at (60±6)%, and the acclimation of glycerol sulfite-ditrophic denitrifying sludge was completed. S2: C14-HSL addition stage: The ship exhaust gas washing waste liquid is treated using a fully mixed anaerobic stirred reactor containing sludge acclimated in step S1. A continuous water inlet method is adopted, and the temperature inside the reactor is 20-40℃. C14-HSL is added to the reactor in three stages, each stage lasting 20-30 days. The concentration of C14-HSL in the three stages increases in the range of 5-10 nmol / L.

2. The method for treating multiple pollutants in ship exhaust gas scrubbing wastewater by adding exogenous C14-HSL according to claim 1, characterized in that, The waste liquid from the ship exhaust gas washing process is generated by treating ship exhaust gas using a supergravity device. The supergravity device uses NaOH, C3H8O3, and NaClO as the absorbent, additive, and oxidant, respectively.

3. The method for treating multiple pollutants in ship exhaust gas scrubbing wastewater by adding exogenous C14-HSL according to claim 1, characterized in that, In step S1, no C14-HSL is added; in step S2, SO3 is added to the influent of the completely mixed anaerobic stirred reactor. 2- The concentration of sulfur (S) is 500-700 mg / L, the concentration of glycerol (C) is 300-400 mg / L, and the concentration of NO3 is... - The nitrogen concentration is 150-200 mg / L, and the sulfur concentration in the effluent is monitored every 12-36 hours. 2- SO4 2- SO3 2- NO3 - and TOC concentration.

4. The method for treating multiple pollutants in ship exhaust gas scrubbing wastewater by adding exogenous C14-HSL according to claim 1, characterized in that, In step S1, the stirring speed in the reactor is 15-20 r / min; in step S2, the stirring speed in the reactor is 20-30 r / min.

5. The method for treating multiple pollutants in ship exhaust gas scrubbing wastewater by adding exogenous C14-HSL according to claim 1, characterized in that, The acclimatization water is artificially prepared water or waste liquid from ship exhaust gas washing.

6. The method for treating multiple pollutants in ship exhaust gas scrubbing wastewater by adding exogenous C14-HSL according to claim 1, characterized in that, The inoculation concentration of aerobic sludge is 20-40 g MLVSS / L.

7. The method for treating multiple pollutants in ship exhaust gas scrubbing wastewater by adding exogenous C14-HSL according to claim 1, characterized in that, In step S1, the dominant bacterial genera in the acclimated activated sludge include Desulfomicrobium , Brevefilum , UBA6170 , Stutzerimonas , Thiobacillus and Desulfatitalea .

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