This study aimed to present a novel clay/biochar composite adsorption particle, which made from abandoned reed straw and clay to remove ammonia nitrogen(NH4^+-N) from micro-contaminated water. The removal performance ...This study aimed to present a novel clay/biochar composite adsorption particle, which made from abandoned reed straw and clay to remove ammonia nitrogen(NH4^+-N) from micro-contaminated water. The removal performance of NH4^+-N by composite adsorption particle was monitored under different raw material proportions and initial NH4^+-N concentration. Besides, adsorption kinetics and adsorption isotherms were investigated to reveal the adsorption mechanisms. The results showed that NH4^+-N was effectively removed under optimal proportion of biochar, foaming agent and crosslinker with 20%, 3%, and 3%, respectively. The optimal contact time was 150 min and the best removal efficiency was 88.6% at initial NH4^+-N concentration of 20 mg L^-1. The adsorption performance was well described by the second order kinetic model and Freundlich model. The novel clay/biochar composite adsorption particle in this study demonstrated a high potential for NH4^+-N removal from surface water.展开更多
Determination of ammonia nitrogen content in water is the basic item of the environmental water pollution, and is the key index to evaluate the water quality. This article designs a water quality monitoring system bas...Determination of ammonia nitrogen content in water is the basic item of the environmental water pollution, and is the key index to evaluate the water quality. This article designs a water quality monitoring system based on the on-line automatic ammonia nitrogen monitoring system, and establishes a forecasting model based on the weighted least squares support vector machine algorithm. The weighted least squares support vector machine algorithm increases the weight parameter setting, improves the speed and accuracy of prediction learning, and improves the robustness. In this article, a comparison between neural network model and weighted least square support vector machine model is made, which shows that the weighted least squares support vector machine model has better prediction accuracy.展开更多
In this study, the relationship of the growth of invasion fish with water eutrophication processes was explored in Yangtze estuary, China. High water ammonia nitrogen concentration produced high effects on the growth ...In this study, the relationship of the growth of invasion fish with water eutrophication processes was explored in Yangtze estuary, China. High water ammonia nitrogen concentration produced high effects on the growth and survival of mosquitofish Gambusia affinis. When the ammonia nitrogen was higher than 51.75 mg/l, the fish death rate obviously increased with days, and at the 4th day fish presented the highest mortality, while 23.72 mg/l ammonia nitrogen conditions have been able to ensure fish survival for two days in experiment treatment. Therefore, ammonia nitrogen of Grade V polluted water (national water quality criteria) is just 3 mg/l, and the water can be enough to support fish normal survival. Our results suggest mosquitofish was a suitable pioneer species for restoring polluted water ecology and purify water.展开更多
[Objectives]To investigate the removal effect of nitrifying bacteria on ammonia nitrogen in water.[Methods]In this experiment,the treated water(referred to as raw water hereinafter)from the Changping Town Qiaoli Water...[Objectives]To investigate the removal effect of nitrifying bacteria on ammonia nitrogen in water.[Methods]In this experiment,the treated water(referred to as raw water hereinafter)from the Changping Town Qiaoli Water Treatment Project in Dongguan City of Guangdong Province was used as the experimental water body,and the nitrifying bacteria liquid used in the project was taken as the experimental material,to explore the removal effect of the nitrifying bacteria liquid on the ammonia nitrogen in the water body.[Results]Under the condition that other variables remain unchanged,the more the amount of nitrifying bacteria liquid added,the higher the removal efficiency of nitrifying bacteria liquid;under the same conditions,the removal effect of ammonia nitrogen in a stirred water body is better than that in an unstirred water body;the removal effect of ammonia nitrogen in a water body with bio-media/carriers is better than that without bio-media/carriers.[Conclusions]Nitrifying bacteria have a better removal effect on the ammonia nitrogen in the water body.展开更多
The characteristics of the zeolite modified by microwave and sodium acetate and its sorption of ammonia-nitrogen from simulated water sample were investigated.The results show that the modified zeolite by microwave-so...The characteristics of the zeolite modified by microwave and sodium acetate and its sorption of ammonia-nitrogen from simulated water sample were investigated.The results show that the modified zeolite by microwave-sodium acetate(SMMZ)has a high sorption efficiency and removal performance.The ammonia-nitrogen removal rate of SMMZ reaches 92.90%.The surface of SMMZ becomes loose and some pores appear,the specific surface area,total pore volume and average pore diameter increase after modification.Compared to the natural zeolite,SMMZ has a more concentrated pore size distribution in the range of 0-10 nm.The cation exchange capacity(CEC)of SMMZ is higher than that of the natural zeolite.And the ammonia nitrogen removal rate is consistent with the change of CEC.The SMMZ possesses rapid sorption and slow balance characteristics and ammonia-nitrogen sorption is consistent with both Langmuir adsorption isotherm model and Freundlich adsorption isotherm model.The adsorption kinetics of ammonia-nitrogen follows the pseudo-second order kinetic model.展开更多
A series of batch experiments were conducted in 125mL serum bottles to assess the toxicity of different concentrations of ammonia nitrogen to the specific methanogenic activity of anaerobic granular sludge from upfl...A series of batch experiments were conducted in 125mL serum bottles to assess the toxicity of different concentrations of ammonia nitrogen to the specific methanogenic activity of anaerobic granular sludge from upflow anaerobic sludge bed(UASB) and expanded granular sludge bed(EGSB) reactors. The effects of pH value and temperature on toxicity of ammonia nitrogen to anaerobes were investigated. The results show that the specific methanogenic activity of anaerobic granular sludge suffers inhibition from ammonia nitrogen, the concentrations of ammonia nitrogen that produce 50% inhibition of specific methanogenic activity for sludge from UASB and EGSB reactor are 2.35 and 2.75g/L, respectively. Hydrogen utilizing methanogens suffers less inhibition from ammonia nitrogen than that of acetate utilizing methanogens. Hydrogen-producing acetogens that utilize propionate and butyrate as substrates suffer serious inhibition from ammonia nitrogen. The toxicity of ammonia nitrogen to anaerobic granular sludge enhances when pH value and temperature increase. Anaerobic granular sludge can bear higher concentrations of ammonia nitrogen after being acclimated by ammonia nitrogen for 7d.展开更多
This paper presents lab-scale experiment carried out to evaluate the c orrelation between ammonia nitrogen(NH3-N) and p-toluidine using sequencing batc h reactor treating synthetic p-toluidine wastewater. The profiles...This paper presents lab-scale experiment carried out to evaluate the c orrelation between ammonia nitrogen(NH3-N) and p-toluidine using sequencing batc h reactor treating synthetic p-toluidine wastewater. The profiles of NH3-N and p -toluidine were traced under the concentration of sucrose in the influent varied from 0 to 500 mg/L, aerated airflow varied from 0.6 to 1.2 L/min and temperatur e varied from 10 to 25℃, respectively. The results showed that the concentratio n of NH3-N turned from increase to decrease when p-toluidine was nearly complete ly biodegraded, so the profile of NH3-N could clearly indicate the endpoint of p -toluidine biodegradation. And the profile of NH3-N was not influenced by the su crose in the influent, aerated airflow and temperature. It is showed that using ammonia nitrogen as monitoring and control parameter is feasible and reliable an d has promising application in amine wastewater treatment by SBR.展开更多
The influencing factors and kinetics of oxidative degradation of ammonia nitrogen in high salinity wastewater by sodium hypochlorite oxidation( Na Cl O) were studied. The results showed that the degradation process of...The influencing factors and kinetics of oxidative degradation of ammonia nitrogen in high salinity wastewater by sodium hypochlorite oxidation( Na Cl O) were studied. The results showed that the degradation process of ammonia nitrogen by sodium hypochlorite accorded with a pseudo first-order kinetics model,and the influencing factors included Na Cl O dosage,initial concentration of ammonia nitrogen,salinity,temperature,and so on. When Na Cl O dosage was 0. 6%( MCl∶ MN= 13. 76),the reaction rate constant was up to 0. 015 75 min^(-1). The higher the initial concentration of ammonia nitrogen was,the worse the effect of oxidation reaction was. When the initial concentration did not exceed 45 mg/L,the effect on oxidation reaction rate constant increased with the increase of the initial concentration. Low salinity had no effect on ammonia nitrogen oxidation.When salinity was higher than 2. 0%,the inhibition effect on ammonia nitrogen oxidation would increase,and the reaction rate constant decreased obviously with the increase of salinity. The improvement of reaction temperature was beneficial to ammonia oxidation degradation. As temperature increased from 10 to 35 ℃,the reaction rate constant rose from 0. 00188 to 0. 01043 min^(-1).展开更多
Nine strains of ammonia nitrogen degradation strains from C1 to C9 were isolated from industrial wastewater to study their degradation and conversion of ammonia nitrogen. The results showed that C2 strain with a high ...Nine strains of ammonia nitrogen degradation strains from C1 to C9 were isolated from industrial wastewater to study their degradation and conversion of ammonia nitrogen. The results showed that C2 strain with a high degradation activiity of ammonia nitrogen, and the ammonia nitrogen degradation rate of the activated C2 strain was 93% within 24 h when the initial concentration of ammonia nitrogen was 200 mg/L under the conditions of inoculation 10%, temperature 35?C, pH 7.0, rotation 200 r/min. And C2 was identified as Bacillus amyloliquefaciens.展开更多
[Objective]The study aimed to discuss the feasibility and optimal conditions of removing ammonia nitrogen by using microwave coupled with active carbon. [Method]In the study,a novel process,microwave radiation coupled...[Objective]The study aimed to discuss the feasibility and optimal conditions of removing ammonia nitrogen by using microwave coupled with active carbon. [Method]In the study,a novel process,microwave radiation coupled with active carbon,was applied to remove ammonia nitrogen from wastewater,and the influences of solution pH,air conditions,active carbon usage,microwave power and time on the removal effect of ammonia nitrogen were studied. [Result]Microwave coupled with active carbon can remove ammonia nitrogen efficiently,and pumping air into the wastewater can also increase the removal rate of ammonia nitrogen to a certain extent. Higher pH,intensive microwave power and longer treating time could also increase the removal rate of ammonia nitrogen using microwave radiation coupled with active carbon,whereas the usage of active carbon contributed a small impact. It was proved that microwave coupled with active carbon was an effective method for the removal of ammonia nitrogen from wastewater. Meanwhile,the orthogonal experiment results showed that the removal rate of ammonia nitrogen reached 92. 5% under the optimal conditions,that is,the usage of active carbon was 0. 5 g,pH =11,microwave radiation power was 850 W,and microwave action time was 4 minutes. [Conclusion]The research provided a new method to remove ammonia nitrogen from wastewater,namely microwave coupled with active carbon.展开更多
[Objective] The study aimed to discuss the effects of different concentrations of ammonia nitrogen on N2O emission in the process of partial nitrification. [Method] By using a sequencing batch biofilm reactor (SBBR) u...[Objective] The study aimed to discuss the effects of different concentrations of ammonia nitrogen on N2O emission in the process of partial nitrification. [Method] By using a sequencing batch biofilm reactor (SBBR) under intermittent aeration, the influences of various concentrations of influent ammonia nitrogen on nitrous oxide (N2O) emission from partial nitrification were analyzed. [Result] When the concentration of influent ammonia nitrogen varied from 200 to 400 mg/L, the changing trends of DO and ORP value were consistent during the process of partial nitrification, and the concentration ratio of NO-2-N to NH+4-N in effluent water reached 1∶1, with lower NO-3-N level. In addition, ammonia nitrogen concentration in the influent had significant effects on N2O emission in the process of partial nitrification, that is, the higher the ammonia nitrogen concentration, the more the N2O emission. When ammonia nitrogen concentration was 400 mg/L, N2O emission was up to about 37 mg. [Conclusion] N2O emission in the process of partial nitrification might be related to the concentrations of NH+4 and NO-2.展开更多
Red brick,cement brick and ceramsite were taken as the substrate of constructed wetland,and removal effect of ammonia nitrogen by the mixed substrate under different combination manners and aeration condition was expl...Red brick,cement brick and ceramsite were taken as the substrate of constructed wetland,and removal effect of ammonia nitrogen by the mixed substrate under different combination manners and aeration condition was explored. Research results showed that cement brick had the best removal effect on ammonia nitrogen,followed by red brick and ceramsite; aeration was favorable for the removal of ammonia nitrogen by each substrate and the mixed substrate; removal rate sequence of ammonia nitrogen by each mixed substrate was red brick + cement brick > red brick + cement brick + ceramsite > cement brick + ceramsite > red brick + ceramsite; the combination of red brick + cement brick had the best removal effect on ammonia nitrogen in domestic sewage. Comprehensively considering,the mixed substrate of red brick + cement brick has better stability and higher ammonia nitrogen removal rate,and it is suitable as the mixed adsorption substrate of constructed wetland.展开更多
Active iron catalysts with 5A molecular sieve as the carrier were prepared firstly, and then were used in the treatment of ammonia nitrogen in landfill leachate pretreated by MBR by using CWPO, finally the effects of ...Active iron catalysts with 5A molecular sieve as the carrier were prepared firstly, and then were used in the treatment of ammonia nitrogen in landfill leachate pretreated by MBR by using CWPO, finally the effects of preparation process of catalysts, assistants and reaction conditions on the removal rate of ammonia nitrogen were analyzed. The results show that the preparation process of catalysts and assistants had great effects on catalytic activity; when steeping fluid concentration was 2 mol/L and 0.01 mol/L cerium nitrate was used as an assistant, Fe-Ce/5A catalyst roasted for 3 h at 400 ℃ had a good catalytic effect. As 10 g of Fe-Ce/5A catalyst was added to water sample, and landfill leachate pretreated by MBR reacted with 15 ml of H2O2 for 30 min at 60 ℃, the removal rate of ammonia nitrogen was up to 90.8%, that is, ammonia nitrogen concentration decreased from 253 to 23 mg/L, reaching the national emission standard. Besides, the kinetic analysis of ammonia nitrogen removal reveals that the removal reaction of ammonia nitrogen conformed with pseudo first order kinetic equation. Thus, it is feasible to use this method to deeply treat landfill leachate pretreated by MBR.展开更多
The biological treatment of wastewater with high concentrations of ammonia nitrogen has become a hot research issue,but there are limited reports on the mechanism of ammonia nitrogen utilization by microorganisms.In t...The biological treatment of wastewater with high concentrations of ammonia nitrogen has become a hot research issue,but there are limited reports on the mechanism of ammonia nitrogen utilization by microorganisms.In this paper,a transcriptomic approach was used to investigate the differences in gene expression at 500.0 mg/L(Amo 500)and 100.0 mg/L(Amo 100)ammonium concentrations to reveal the mechanism of ammonia nitrogen removal from water by Pseudomonas stutzeri F2.The transcriptome data showed 1015(459 up-regulated and 556 down-regulated)differentially expressed genes with functional gene annotation related to nitrogen source metabolism,glycolysis,tricarboxylic acid cycle,extracellular polysaccharide synthesis,energy conversion and transmembrane transport,revealing the metabolic process of ammonium nitrogen conversion to biological ni-trogen in P.stutzeri F2 through assimilation.To verify the effect of ammonium transporter protein(AmtB)of cell membrane on assimilation,a P.stutzeri F2-ΔamtB mutant strain was obtained by constructing a knockout plasmid(pK18mobsacB-ΔamtB),and it was found that the growth characteristics and ammonium removal rate of the mutant strain were significantly reduced at high ammonium concentration.The carbon source components and dissolved oxygen conditions were optimized after analyzing the transcriptome data,and the ammonium removal rate was increased from 41.23%to 94.92%with 500.0 mg/L ammonium concentration.The study of P.stutzeri F2 transcript level reveals the mechanism of ammonia nitrogen influence on microbial assimilation process and improvement strategy,which provides a new strategy for the treatment of ammonia nitrogen wastewater.展开更多
The effects of chlorine dioxide and chlorine disinfections on the genotoxicity of different biologically treated sewage wastewater samples were studied by umu-test.The experiment results showed that when chlorine diox...The effects of chlorine dioxide and chlorine disinfections on the genotoxicity of different biologically treated sewage wastewater samples were studied by umu-test.The experiment results showed that when chlorine dioxide dosage was increased from 0 to 30 mg/L,the genotoxicity of wastewater first decreased rapidly and then tended to be stable,while when the chlorine dosage was increased from 0 to 30 mg/L,the genotoxicity of wastewater changed diver sely for different samples.It was then found that ammonia nitro-gen did not affect the change of genotoxicity during chlorine dioxide disinfection of wastewater,while it greatly affected the change of genotoxicity during chlorine disin fection of wastewater.When the concentration of ammonia nitrogen was low(<10-20 mg/L),the genotoxicity of wastewater decreased after chlorine disinfection,and when the con-centration of ammonia nitrogen was high(>10-20 mg/L),the genotoxicity of wastewater increased after chlorine disinfection.展开更多
Ammonia nitrogen is one of the key parameters in determining the aquaculture water quality condition in pond.The high level of ammonia nitrogen is likely to cause deterioration of water quality and mass death of cultu...Ammonia nitrogen is one of the key parameters in determining the aquaculture water quality condition in pond.The high level of ammonia nitrogen is likely to cause deterioration of water quality and mass death of cultured subjects.Therefore,accurate detection of the cultured water ammonia nitrogen content is crucially important for aquaculture management.While,at present,the accuracy of equipment for measuring the ammonia nitrogen content of aquaculture water in real time cannot meet the requirements for aquaculture.In this paper,the soft computing method is firstly proposed to predict the ammonia nitrogen content in aquaculture water in real time.This method includes empirical mode decomposition(EMD),improved particle swarm optimization(IPSO)and extreme learning machine(ELM).To evaluate the performance of the soft computing techniques,three different statistic indicators were used,including root mean square error(RMSE),the mean absolute error(MAE),and the mean absolute percentage error(MAPE)to compare three artificial soft computing methods.Results showed that the EMD-IPSO-ELM soft computing method showed the best performance among other studied methods in the ammonia nitrogen real time prediction.The EMD-IPSO-ELM model provides moderately and roughly accurately real time prediction value of ammonia nitrogen in aquaculture water.展开更多
An efficient ammonia nitrogen degrading bacterial strain was isolated from a fish and shrimp pond and identified as Bacillus subtilis(Ab03).Firstly,the strain was continuously domesticated in ammonium solution to impr...An efficient ammonia nitrogen degrading bacterial strain was isolated from a fish and shrimp pond and identified as Bacillus subtilis(Ab03).Firstly,the strain was continuously domesticated in ammonium solution to improve its nitrogen removal capacity.The performance of the strain in terms of nitrogen removal efficiency under different culture conditions was then examined.Finally,the nitrogen removal process and related strain mechanisms were analyzed by nitrogen balance.The results showed the strain Ab03 could remove 91.67% of NH_(4)^(+)-N at 300 mg/L under the conditions of glucose as the single carbon source,C/N of 15,pH of 7.5,the temperature of 35℃ and dissolved oxygen of 7-8 mg/L.It was also found that under conditions where ammonia nitrogen was the only nitrogen source,strain Ab03 could also undergo aerobic denitrification for simultaneous conversion,with a final gas conversion rate of 74.81%.展开更多
Portable measurement of ammonia nitrogen in water is of great significance for water qual-ity monitoring.It’s beneficial to reduce biological diseases and promote aquatic product safety.Traditional methods such as Ne...Portable measurement of ammonia nitrogen in water is of great significance for water qual-ity monitoring.It’s beneficial to reduce biological diseases and promote aquatic product safety.Traditional methods such as Nessler’s reagent method suffer from complex opera-tion,time delays and toxic residues.To realize simple and pollution-free detection,this paper develops a low-cost portable device for ammonia nitrogen detection.A test paper was proposed to cooperate the device and offer a chromogenic reaction.The portable device reduces the impact of any ambient light,simplifies the operation,and provides human–computer interaction.The result obtained for the detection range of 0.4–10 mg/L(R^(2) are 0.9902 and 0.9893 for the rang of 0.4–4.5 and 4.5–10 mg/L,respectively)with the detection limit of 0.36 mg/L,and the average recovery of aquaculture water is 100.98–137.75%.The results show that the portable device can provide a great potential for on-site detection ammonia nitrogen concentration.展开更多
Objective:This paper aims to establish a simple and practical method for the rapid detection of ammonia nitrogen in water on the spot,and to transmit the detection results to the Internet via GSM network,and to publis...Objective:This paper aims to establish a simple and practical method for the rapid detection of ammonia nitrogen in water on the spot,and to transmit the detection results to the Internet via GSM network,and to publish and update them in real time.Methods:Phenol salt colorimetry was used to measure the absorbance value of indigo phenol blue,the product of the reaction between ammonia nitrogen and phenol salt in water samples,using sodium nitrosoferricyanide sodium hydroxide as catalyst and a microphotoelectric colorimetric instrument developed by ourselves,or a simple visual colorimetric semi-quantitative method was used to measure the ammonia nitrogen content in water samples.Then,the general GSM wireless communication module built in the microphotoelectric colorimeter was used to realize the remote transmission of the test result data and the real-time update and release on the Internet.Results:The results of this method showed that the correlation of the method was significant,and the precision and accuracy were similar to the national standard Nessler's reagent spectrophotometry.The relative standard deviation is 4.4%,and the relative error is 2.7%.In 5-10 min,the detection of ammonia and nitrogen in single water sample can be completed on site,and the results can be released.For quantitative and semi-quantitative detection,the lowest detection concentrations are 0.05 mg/L and 0.2 mg/L,respectively,which are basically free from the interference of pH and common ions.In the coverage area of GSM network,the wireless transmission of data results was unobstructed and delayed,and the effect was satisfactory.Conclusion:The method is simple,rapid,practical and reliable,which is suitable for the field rapid determination of ammonia nitrogen in water,and the real-time remote transmission of the detection results.It provides a high-efficiency,low-cost and simple technical means for the field water quality monitoring and the rapid acquisition of water quality data.展开更多
基金supported by the National Major Project of Water Pollution Control and Management Technology in China (No.2013ZX07202-007)the Shenzhen Science and Technology Project (No.GRCK2017042116092660)the National Natural Science Foundation of China (No.51308066)。
文摘This study aimed to present a novel clay/biochar composite adsorption particle, which made from abandoned reed straw and clay to remove ammonia nitrogen(NH4^+-N) from micro-contaminated water. The removal performance of NH4^+-N by composite adsorption particle was monitored under different raw material proportions and initial NH4^+-N concentration. Besides, adsorption kinetics and adsorption isotherms were investigated to reveal the adsorption mechanisms. The results showed that NH4^+-N was effectively removed under optimal proportion of biochar, foaming agent and crosslinker with 20%, 3%, and 3%, respectively. The optimal contact time was 150 min and the best removal efficiency was 88.6% at initial NH4^+-N concentration of 20 mg L^-1. The adsorption performance was well described by the second order kinetic model and Freundlich model. The novel clay/biochar composite adsorption particle in this study demonstrated a high potential for NH4^+-N removal from surface water.
文摘Determination of ammonia nitrogen content in water is the basic item of the environmental water pollution, and is the key index to evaluate the water quality. This article designs a water quality monitoring system based on the on-line automatic ammonia nitrogen monitoring system, and establishes a forecasting model based on the weighted least squares support vector machine algorithm. The weighted least squares support vector machine algorithm increases the weight parameter setting, improves the speed and accuracy of prediction learning, and improves the robustness. In this article, a comparison between neural network model and weighted least square support vector machine model is made, which shows that the weighted least squares support vector machine model has better prediction accuracy.
文摘In this study, the relationship of the growth of invasion fish with water eutrophication processes was explored in Yangtze estuary, China. High water ammonia nitrogen concentration produced high effects on the growth and survival of mosquitofish Gambusia affinis. When the ammonia nitrogen was higher than 51.75 mg/l, the fish death rate obviously increased with days, and at the 4th day fish presented the highest mortality, while 23.72 mg/l ammonia nitrogen conditions have been able to ensure fish survival for two days in experiment treatment. Therefore, ammonia nitrogen of Grade V polluted water (national water quality criteria) is just 3 mg/l, and the water can be enough to support fish normal survival. Our results suggest mosquitofish was a suitable pioneer species for restoring polluted water ecology and purify water.
基金Special Project in Key Fields of Higher Education Institutions in Guangdong Province(Science and Technology Serving Rural Revitalization)“Research and Development of Key Technologies for the Utilization of Manure from Large-scale Livestock and Poultry Breeding in Rural Areas of Western Guangdong”(2021ZDZX4023)Special Fund Project for Enterprise Science and Technology Commissioners of Guangdong Province in 2020(GDKTP2020059100)+2 种基金Quality Engineering and Educational Reform Project of Zhaoqing University(zlgc 201931)Guangdong University Innovation Team(2021KCXTD055)Guangdong Provincial Key Laboratory of Environmental Health and Land Resource(2020B121201014).
文摘[Objectives]To investigate the removal effect of nitrifying bacteria on ammonia nitrogen in water.[Methods]In this experiment,the treated water(referred to as raw water hereinafter)from the Changping Town Qiaoli Water Treatment Project in Dongguan City of Guangdong Province was used as the experimental water body,and the nitrifying bacteria liquid used in the project was taken as the experimental material,to explore the removal effect of the nitrifying bacteria liquid on the ammonia nitrogen in the water body.[Results]Under the condition that other variables remain unchanged,the more the amount of nitrifying bacteria liquid added,the higher the removal efficiency of nitrifying bacteria liquid;under the same conditions,the removal effect of ammonia nitrogen in a stirred water body is better than that in an unstirred water body;the removal effect of ammonia nitrogen in a water body with bio-media/carriers is better than that without bio-media/carriers.[Conclusions]Nitrifying bacteria have a better removal effect on the ammonia nitrogen in the water body.
基金Project(51174017) supported by the National Natural Science Foundation of China
文摘The characteristics of the zeolite modified by microwave and sodium acetate and its sorption of ammonia-nitrogen from simulated water sample were investigated.The results show that the modified zeolite by microwave-sodium acetate(SMMZ)has a high sorption efficiency and removal performance.The ammonia-nitrogen removal rate of SMMZ reaches 92.90%.The surface of SMMZ becomes loose and some pores appear,the specific surface area,total pore volume and average pore diameter increase after modification.Compared to the natural zeolite,SMMZ has a more concentrated pore size distribution in the range of 0-10 nm.The cation exchange capacity(CEC)of SMMZ is higher than that of the natural zeolite.And the ammonia nitrogen removal rate is consistent with the change of CEC.The SMMZ possesses rapid sorption and slow balance characteristics and ammonia-nitrogen sorption is consistent with both Langmuir adsorption isotherm model and Freundlich adsorption isotherm model.The adsorption kinetics of ammonia-nitrogen follows the pseudo-second order kinetic model.
文摘A series of batch experiments were conducted in 125mL serum bottles to assess the toxicity of different concentrations of ammonia nitrogen to the specific methanogenic activity of anaerobic granular sludge from upflow anaerobic sludge bed(UASB) and expanded granular sludge bed(EGSB) reactors. The effects of pH value and temperature on toxicity of ammonia nitrogen to anaerobes were investigated. The results show that the specific methanogenic activity of anaerobic granular sludge suffers inhibition from ammonia nitrogen, the concentrations of ammonia nitrogen that produce 50% inhibition of specific methanogenic activity for sludge from UASB and EGSB reactor are 2.35 and 2.75g/L, respectively. Hydrogen utilizing methanogens suffers less inhibition from ammonia nitrogen than that of acetate utilizing methanogens. Hydrogen-producing acetogens that utilize propionate and butyrate as substrates suffer serious inhibition from ammonia nitrogen. The toxicity of ammonia nitrogen to anaerobic granular sludge enhances when pH value and temperature increase. Anaerobic granular sludge can bear higher concentrations of ammonia nitrogen after being acclimated by ammonia nitrogen for 7d.
文摘This paper presents lab-scale experiment carried out to evaluate the c orrelation between ammonia nitrogen(NH3-N) and p-toluidine using sequencing batc h reactor treating synthetic p-toluidine wastewater. The profiles of NH3-N and p -toluidine were traced under the concentration of sucrose in the influent varied from 0 to 500 mg/L, aerated airflow varied from 0.6 to 1.2 L/min and temperatur e varied from 10 to 25℃, respectively. The results showed that the concentratio n of NH3-N turned from increase to decrease when p-toluidine was nearly complete ly biodegraded, so the profile of NH3-N could clearly indicate the endpoint of p -toluidine biodegradation. And the profile of NH3-N was not influenced by the su crose in the influent, aerated airflow and temperature. It is showed that using ammonia nitrogen as monitoring and control parameter is feasible and reliable an d has promising application in amine wastewater treatment by SBR.
基金Supported by Project for Achievement Transformation of High and New Technology in Shanghai City(201405267)
文摘The influencing factors and kinetics of oxidative degradation of ammonia nitrogen in high salinity wastewater by sodium hypochlorite oxidation( Na Cl O) were studied. The results showed that the degradation process of ammonia nitrogen by sodium hypochlorite accorded with a pseudo first-order kinetics model,and the influencing factors included Na Cl O dosage,initial concentration of ammonia nitrogen,salinity,temperature,and so on. When Na Cl O dosage was 0. 6%( MCl∶ MN= 13. 76),the reaction rate constant was up to 0. 015 75 min^(-1). The higher the initial concentration of ammonia nitrogen was,the worse the effect of oxidation reaction was. When the initial concentration did not exceed 45 mg/L,the effect on oxidation reaction rate constant increased with the increase of the initial concentration. Low salinity had no effect on ammonia nitrogen oxidation.When salinity was higher than 2. 0%,the inhibition effect on ammonia nitrogen oxidation would increase,and the reaction rate constant decreased obviously with the increase of salinity. The improvement of reaction temperature was beneficial to ammonia oxidation degradation. As temperature increased from 10 to 35 ℃,the reaction rate constant rose from 0. 00188 to 0. 01043 min^(-1).
文摘Nine strains of ammonia nitrogen degradation strains from C1 to C9 were isolated from industrial wastewater to study their degradation and conversion of ammonia nitrogen. The results showed that C2 strain with a high degradation activiity of ammonia nitrogen, and the ammonia nitrogen degradation rate of the activated C2 strain was 93% within 24 h when the initial concentration of ammonia nitrogen was 200 mg/L under the conditions of inoculation 10%, temperature 35?C, pH 7.0, rotation 200 r/min. And C2 was identified as Bacillus amyloliquefaciens.
基金Supported by National Key Project of Science and Technology of Water Pollution Control and Management(2009ZX07212-001-04)
文摘[Objective]The study aimed to discuss the feasibility and optimal conditions of removing ammonia nitrogen by using microwave coupled with active carbon. [Method]In the study,a novel process,microwave radiation coupled with active carbon,was applied to remove ammonia nitrogen from wastewater,and the influences of solution pH,air conditions,active carbon usage,microwave power and time on the removal effect of ammonia nitrogen were studied. [Result]Microwave coupled with active carbon can remove ammonia nitrogen efficiently,and pumping air into the wastewater can also increase the removal rate of ammonia nitrogen to a certain extent. Higher pH,intensive microwave power and longer treating time could also increase the removal rate of ammonia nitrogen using microwave radiation coupled with active carbon,whereas the usage of active carbon contributed a small impact. It was proved that microwave coupled with active carbon was an effective method for the removal of ammonia nitrogen from wastewater. Meanwhile,the orthogonal experiment results showed that the removal rate of ammonia nitrogen reached 92. 5% under the optimal conditions,that is,the usage of active carbon was 0. 5 g,pH =11,microwave radiation power was 850 W,and microwave action time was 4 minutes. [Conclusion]The research provided a new method to remove ammonia nitrogen from wastewater,namely microwave coupled with active carbon.
基金Supported by National Scientific Project of Water Pollution Control and Management(2008ZX07209-006,2009ZX07210-009)
文摘[Objective] The study aimed to discuss the effects of different concentrations of ammonia nitrogen on N2O emission in the process of partial nitrification. [Method] By using a sequencing batch biofilm reactor (SBBR) under intermittent aeration, the influences of various concentrations of influent ammonia nitrogen on nitrous oxide (N2O) emission from partial nitrification were analyzed. [Result] When the concentration of influent ammonia nitrogen varied from 200 to 400 mg/L, the changing trends of DO and ORP value were consistent during the process of partial nitrification, and the concentration ratio of NO-2-N to NH+4-N in effluent water reached 1∶1, with lower NO-3-N level. In addition, ammonia nitrogen concentration in the influent had significant effects on N2O emission in the process of partial nitrification, that is, the higher the ammonia nitrogen concentration, the more the N2O emission. When ammonia nitrogen concentration was 400 mg/L, N2O emission was up to about 37 mg. [Conclusion] N2O emission in the process of partial nitrification might be related to the concentrations of NH+4 and NO-2.
基金Supported by Youth Innovative Talents Project of Provincial Major Scientific Research Project of Guangdong University in 2015(2015KQNCX225)Social Development Project of Dongguan City in2014(2014106101025)Youth Fund Project of City College of Dongguan University of Technology in 2015(2015QJZ008Z)
文摘Red brick,cement brick and ceramsite were taken as the substrate of constructed wetland,and removal effect of ammonia nitrogen by the mixed substrate under different combination manners and aeration condition was explored. Research results showed that cement brick had the best removal effect on ammonia nitrogen,followed by red brick and ceramsite; aeration was favorable for the removal of ammonia nitrogen by each substrate and the mixed substrate; removal rate sequence of ammonia nitrogen by each mixed substrate was red brick + cement brick > red brick + cement brick + ceramsite > cement brick + ceramsite > red brick + ceramsite; the combination of red brick + cement brick had the best removal effect on ammonia nitrogen in domestic sewage. Comprehensively considering,the mixed substrate of red brick + cement brick has better stability and higher ammonia nitrogen removal rate,and it is suitable as the mixed adsorption substrate of constructed wetland.
基金Supported by the Project of Agricultural Key Programs for Science and Technology Development of Ningbo (2011C11006)Key Spark Program Project of Science and Technology Ministry (2012GA7010011)the Science and Technology Plan Project of Ningbo City,Zhejiang Province
文摘Active iron catalysts with 5A molecular sieve as the carrier were prepared firstly, and then were used in the treatment of ammonia nitrogen in landfill leachate pretreated by MBR by using CWPO, finally the effects of preparation process of catalysts, assistants and reaction conditions on the removal rate of ammonia nitrogen were analyzed. The results show that the preparation process of catalysts and assistants had great effects on catalytic activity; when steeping fluid concentration was 2 mol/L and 0.01 mol/L cerium nitrate was used as an assistant, Fe-Ce/5A catalyst roasted for 3 h at 400 ℃ had a good catalytic effect. As 10 g of Fe-Ce/5A catalyst was added to water sample, and landfill leachate pretreated by MBR reacted with 15 ml of H2O2 for 30 min at 60 ℃, the removal rate of ammonia nitrogen was up to 90.8%, that is, ammonia nitrogen concentration decreased from 253 to 23 mg/L, reaching the national emission standard. Besides, the kinetic analysis of ammonia nitrogen removal reveals that the removal reaction of ammonia nitrogen conformed with pseudo first order kinetic equation. Thus, it is feasible to use this method to deeply treat landfill leachate pretreated by MBR.
基金supported by Foundation of Fujian Key Laboratory of Functional Aquafeed and Culture Environment Control(No.FACE20200003)111 Project(111-2-06)and Jiangsu province“Collaborative Innovation Center for Advanced Industrial Fermentation”industry development program.
文摘The biological treatment of wastewater with high concentrations of ammonia nitrogen has become a hot research issue,but there are limited reports on the mechanism of ammonia nitrogen utilization by microorganisms.In this paper,a transcriptomic approach was used to investigate the differences in gene expression at 500.0 mg/L(Amo 500)and 100.0 mg/L(Amo 100)ammonium concentrations to reveal the mechanism of ammonia nitrogen removal from water by Pseudomonas stutzeri F2.The transcriptome data showed 1015(459 up-regulated and 556 down-regulated)differentially expressed genes with functional gene annotation related to nitrogen source metabolism,glycolysis,tricarboxylic acid cycle,extracellular polysaccharide synthesis,energy conversion and transmembrane transport,revealing the metabolic process of ammonium nitrogen conversion to biological ni-trogen in P.stutzeri F2 through assimilation.To verify the effect of ammonium transporter protein(AmtB)of cell membrane on assimilation,a P.stutzeri F2-ΔamtB mutant strain was obtained by constructing a knockout plasmid(pK18mobsacB-ΔamtB),and it was found that the growth characteristics and ammonium removal rate of the mutant strain were significantly reduced at high ammonium concentration.The carbon source components and dissolved oxygen conditions were optimized after analyzing the transcriptome data,and the ammonium removal rate was increased from 41.23%to 94.92%with 500.0 mg/L ammonium concentration.The study of P.stutzeri F2 transcript level reveals the mechanism of ammonia nitrogen influence on microbial assimilation process and improvement strategy,which provides a new strategy for the treatment of ammonia nitrogen wastewater.
文摘The effects of chlorine dioxide and chlorine disinfections on the genotoxicity of different biologically treated sewage wastewater samples were studied by umu-test.The experiment results showed that when chlorine dioxide dosage was increased from 0 to 30 mg/L,the genotoxicity of wastewater first decreased rapidly and then tended to be stable,while when the chlorine dosage was increased from 0 to 30 mg/L,the genotoxicity of wastewater changed diver sely for different samples.It was then found that ammonia nitro-gen did not affect the change of genotoxicity during chlorine dioxide disinfection of wastewater,while it greatly affected the change of genotoxicity during chlorine disin fection of wastewater.When the concentration of ammonia nitrogen was low(<10-20 mg/L),the genotoxicity of wastewater decreased after chlorine disinfection,and when the con-centration of ammonia nitrogen was high(>10-20 mg/L),the genotoxicity of wastewater increased after chlorine disinfection.
基金This work was supported by“the Fundamental Research Funds for the Central Universities”(Project Number:BLX201825)the“Next Generation Precision Aquaculture:R&D on intelligent measurement,control technology”(Project Number:2017YFE0122100).
文摘Ammonia nitrogen is one of the key parameters in determining the aquaculture water quality condition in pond.The high level of ammonia nitrogen is likely to cause deterioration of water quality and mass death of cultured subjects.Therefore,accurate detection of the cultured water ammonia nitrogen content is crucially important for aquaculture management.While,at present,the accuracy of equipment for measuring the ammonia nitrogen content of aquaculture water in real time cannot meet the requirements for aquaculture.In this paper,the soft computing method is firstly proposed to predict the ammonia nitrogen content in aquaculture water in real time.This method includes empirical mode decomposition(EMD),improved particle swarm optimization(IPSO)and extreme learning machine(ELM).To evaluate the performance of the soft computing techniques,three different statistic indicators were used,including root mean square error(RMSE),the mean absolute error(MAE),and the mean absolute percentage error(MAPE)to compare three artificial soft computing methods.Results showed that the EMD-IPSO-ELM soft computing method showed the best performance among other studied methods in the ammonia nitrogen real time prediction.The EMD-IPSO-ELM model provides moderately and roughly accurately real time prediction value of ammonia nitrogen in aquaculture water.
基金supported by the Foundation of Fujian Key Laboratory of Functional Aquafeed and Culture Environment Control(No.FACE20200003)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,Top-notch Academic Programs Project of Jiangsu Higher Education Institutions,1.111 Project(111-2-06)Jiangsu province"Collaborative Innovation Center for Advanced Industrial Fermentation"industry development program.
文摘An efficient ammonia nitrogen degrading bacterial strain was isolated from a fish and shrimp pond and identified as Bacillus subtilis(Ab03).Firstly,the strain was continuously domesticated in ammonium solution to improve its nitrogen removal capacity.The performance of the strain in terms of nitrogen removal efficiency under different culture conditions was then examined.Finally,the nitrogen removal process and related strain mechanisms were analyzed by nitrogen balance.The results showed the strain Ab03 could remove 91.67% of NH_(4)^(+)-N at 300 mg/L under the conditions of glucose as the single carbon source,C/N of 15,pH of 7.5,the temperature of 35℃ and dissolved oxygen of 7-8 mg/L.It was also found that under conditions where ammonia nitrogen was the only nitrogen source,strain Ab03 could also undergo aerobic denitrification for simultaneous conversion,with a final gas conversion rate of 74.81%.
基金The study was supported by Shandong Province Major Science and Technology Innovation Project (Project No.2019JZZY010703)the National Key Research and Devel-opment Program of China:Sino-Malta Fund 2019 (Project No.2019YFE0103700).
文摘Portable measurement of ammonia nitrogen in water is of great significance for water qual-ity monitoring.It’s beneficial to reduce biological diseases and promote aquatic product safety.Traditional methods such as Nessler’s reagent method suffer from complex opera-tion,time delays and toxic residues.To realize simple and pollution-free detection,this paper develops a low-cost portable device for ammonia nitrogen detection.A test paper was proposed to cooperate the device and offer a chromogenic reaction.The portable device reduces the impact of any ambient light,simplifies the operation,and provides human–computer interaction.The result obtained for the detection range of 0.4–10 mg/L(R^(2) are 0.9902 and 0.9893 for the rang of 0.4–4.5 and 4.5–10 mg/L,respectively)with the detection limit of 0.36 mg/L,and the average recovery of aquaculture water is 100.98–137.75%.The results show that the portable device can provide a great potential for on-site detection ammonia nitrogen concentration.
文摘Objective:This paper aims to establish a simple and practical method for the rapid detection of ammonia nitrogen in water on the spot,and to transmit the detection results to the Internet via GSM network,and to publish and update them in real time.Methods:Phenol salt colorimetry was used to measure the absorbance value of indigo phenol blue,the product of the reaction between ammonia nitrogen and phenol salt in water samples,using sodium nitrosoferricyanide sodium hydroxide as catalyst and a microphotoelectric colorimetric instrument developed by ourselves,or a simple visual colorimetric semi-quantitative method was used to measure the ammonia nitrogen content in water samples.Then,the general GSM wireless communication module built in the microphotoelectric colorimeter was used to realize the remote transmission of the test result data and the real-time update and release on the Internet.Results:The results of this method showed that the correlation of the method was significant,and the precision and accuracy were similar to the national standard Nessler's reagent spectrophotometry.The relative standard deviation is 4.4%,and the relative error is 2.7%.In 5-10 min,the detection of ammonia and nitrogen in single water sample can be completed on site,and the results can be released.For quantitative and semi-quantitative detection,the lowest detection concentrations are 0.05 mg/L and 0.2 mg/L,respectively,which are basically free from the interference of pH and common ions.In the coverage area of GSM network,the wireless transmission of data results was unobstructed and delayed,and the effect was satisfactory.Conclusion:The method is simple,rapid,practical and reliable,which is suitable for the field rapid determination of ammonia nitrogen in water,and the real-time remote transmission of the detection results.It provides a high-efficiency,low-cost and simple technical means for the field water quality monitoring and the rapid acquisition of water quality data.
