In order to enhance the hydraulic loading rate (HLR) of a subsurface wastewater infiltration system (SWIS) used in treating domestic sewage, the intermittent operation mode was employed in the SWIS. The results sh...In order to enhance the hydraulic loading rate (HLR) of a subsurface wastewater infiltration system (SWIS) used in treating domestic sewage, the intermittent operation mode was employed in the SWIS. The results show that the intermittent operation mode contributes to the improvement of the HLR and the pollutant removal rate. When the wetting-drying ratio (RwD) was 1.0, the pollutant removal rate increased by (13.6 ± 0.3)% for NH3-N, (20.7 ± 1.1)% for TN, (18.6± 0.4)% for TP, (12.2 ± 0.5)% for BOD, (10.1 ± 0.3)% for COD, and (36.2 ± 1.2)% for SS, compared with pollutant removal rates under the continuous operation mode. The pollutant removal rate declined with the increase of the HLR. The effluent quality met The Reuse of Urban Recycling Water - Water Quality Standard for Scenic Environment Use (GB/T 18921-2002) even when the HLR was as high as 10 cm/d. Hydraulic conductivity, oxidation reduction potential (ORP), the quantity of nitrifying bacteria, and the pollutant removal rate of NH3-N increased with the decrease of the RWD. For the pollutant removal rates of TP, BOD, and COD, there were no significant difference (p 〈 0.05) under different RwDS. The suggested RWD was 1.0. Relative contribution of the pretreatment and SWlS to the pollutant removal was examined, and more than 80% removal of NH3-N, TN, TP, COD, and BOD occurred in the SWIS.展开更多
The pyromellitic dianhydride(PMDA) crosslinked poly(vinyl alcohol)(PVA) was coated on top of the PAN ultrafiltration membrane to form a PVA/PAN composite PV membranes for wastewater desalination. The composite m...The pyromellitic dianhydride(PMDA) crosslinked poly(vinyl alcohol)(PVA) was coated on top of the PAN ultrafiltration membrane to form a PVA/PAN composite PV membranes for wastewater desalination. The composite membranes have high application value in industrial wastewater treatment. By varying the membrane fabrication parameters including the weight percent(wt%) of the PMDA, the crosslink temperature and duration, membrane with the best desalination performance was obtained. The composite membrane with a 2-lm-thick PVA selective layer containing 20 wt% of PMDA and being crosslinked at 100 °C for 2 h showed the highest Na Cl rejection of 99.98% with a water flux of 32.26 L/(m^2 h)at 70 °C using the 35,000 ppm Na Cl aqueous solution as feed. FTIR spectroscopy, wide-angle X-ray diffraction, thermogravimetric analysis and scanning electron microscope have been used to characterize the structures and properties of both the crosslinked PVA dense films and PVA/PAN composite membranes. The effects of the concentrations of PMDA,the crosslinking time and temperature to the membrane water contact angle, swelling degree, salt rejection and water flux were systematically studied.展开更多
Lithium metal batteries(LMBs) promise energy density over 400 Wh kg^(-1).However,they suffer severe electrochemical performance deterioration at sub-zero temperatures.Such failure behavior highly correlates to inferio...Lithium metal batteries(LMBs) promise energy density over 400 Wh kg^(-1).However,they suffer severe electrochemical performance deterioration at sub-zero temperatures.Such failure behavior highly correlates to inferior lithium metal anode(LMA) compatibility and sluggish Li^(+) desolvation.Here,we demonstrate that cyclopentylmethyl ether(CPME) based diluted high-concentration electrolyte(DHCE)enables-60℃ LMBs operation.By leveraging the loose coordination between Li^(+) and CPME,such developed electrolyte boosts the formation of ion clusters to derive anion-dominant interfacial chemistry for enhancing LMA compatibility and greatly accelerates Li^(+) desolvation kinetics.The resulting electrolyte demonstrates high Coulombic efficiencies(CE),providing over 99.5%,99.1%,98.5% and 95% at 25,-20,-40,and-60℃respectively.The assembled Li-S battery exhibits remarkable cyclic stability in-20,and-40℃ at 0.2 C charging and 0.5 C discharging.Even at-60℃,Li-S cell with this designed electrolyte retains> 70% of the initial capacity over 170 cycles.Besides,lithium metal coin cell and pouch cell with10 mg cm^(-2) high S cathode loading exhibit cycling stability at-20℃.This work offers an opportunity for rational designing electrolytes toward low temperature LMBs.展开更多
A new kind of bio-fluid bed used to treat dyes wastewater is described in detail due to its several special features,such as high removal efficiency,simple struc-ture,shock load resistance,etc.By means of analyzing th...A new kind of bio-fluid bed used to treat dyes wastewater is described in detail due to its several special features,such as high removal efficiency,simple struc-ture,shock load resistance,etc.By means of analyzing the experiment data,the results show that the dye wastewater’s organic matter is removed greatly after be-ing treated by this new kind of bio-fluid bed.On the other hand,the removal efficiency of chromaticity of展开更多
With rural population expansion and improvement of the socio-economic standard of living, treatment of rural domestic wastewater has rapidly become a major aspect of environmental concern. Selection of a suitable meth...With rural population expansion and improvement of the socio-economic standard of living, treatment of rural domestic wastewater has rapidly become a major aspect of environmental concern. Selection of a suitable method for treatment of rural domestic wastewater depends on its efficiency, simplicity, and cost-effectiveness. This study investigated the effects of hydraulic retention time (HRT), temperature, and effluent recycling on the treatment efficiency of an anaerobic filter (AF) reactor. The first round of experimental operations was run for three months with HRTs of one, two, and three days, temperatures of 18℃, 21℃, and 24℃, and no effluent recycling. The second round of experimental operations was conducted for another three months with HRTs of three and four days; temperatures of 30.67℃, 30.57℃, and 26.91 ℃ ; and three effluent recycling ratios of 1:1, 1:2, and 2:1. The first round of operations showed removal rates of 32% to 44% for COD, 30% to 35% for TN, 32% to 36% for NH4-N, 19% to 23% for NO3-N, and 12% to 22% for TE In the second round of operations, the removal rates varied from 75% to 81% for COD, 35% to 41% for TN, 31% to 39% for NH4-N, 30% to 34% for NO3-N, and 41% to 48% for TP. The average gas production rates were 6.72 L/d and 7.26 L/d for the first and second rounds of operations, respectively. The gas production rate increased in the second round of operations as a result of applied effluent recycling. The best removal efficiency was obtained for an optimum HRT of three days, a temperature of 30℃, and an effluent recycling ratio of 2:1. The results show that the removal efficiency of the AF reactor was affected by HRT, temperature, and effluent recycling.展开更多
Summary: The efficiency of cold storage red blood cells (CSRBC) or whole blood at -80 ℃ used in 27 Rh(D) negative patients during surgical operation was reported. The Rh(D) negative patients received the transfusion...Summary: The efficiency of cold storage red blood cells (CSRBC) or whole blood at -80 ℃ used in 27 Rh(D) negative patients during surgical operation was reported. The Rh(D) negative patients received the transfusion of CSRBC or whole blood stored at -80 ℃ for 180 to 360 days. The changes in the indexes, such as blood TB, DB, K +, Na +, BUN, Cr, urine protein (URPO), UOB, Hb, HCT, serum total protein, relative to hemolytic reaction and blood volume before and after transfusion were observed. The results showed that after transfusion of CSRBC or whole blood 27 cases were negative for urine protein and UOB, and the levels of BUN and Cr were normal (P>0.05). Blood TB, DB, Hb, and HCT were increased, while pH, blood K + and blood Na + was normal with the difference being not significant before and after operation (P>0.05). Plasma protein was decreased, but there was no significant difference before and after operation (P>0.05). It was suggested that CSRBC or whole blood at -80 ℃ could be safely infused to the Rh(D) negative patients without side effects during the surgical operation.展开更多
Microbial fuel cells(M FCs)represent a new approach for treating w aste w ater along w ith electricity production.The present study addressed electricity production from domestic w astew ater using a mediator-less dou...Microbial fuel cells(M FCs)represent a new approach for treating w aste w ater along w ith electricity production.The present study addressed electricity production from domestic w astew ater using a mediator-less double chamber M FC.The electricity production w as monitored under different operational conditions for both summer and w inter samples.Optimization of the anodic and cathodic chambers resulted in a maximal current of 0.784 and 0.645 m A w ith the maximal pow er intensity of 209 and 117 m W/m2in pow er duration of 24 h for the summer and w inter samples,respectively.Scanning electron microscopy show ed that the bacterial biofilm formation on the anode w as denser for the summer sample than that w hen the w inter sample w as used,so w as the total bacterial count.Therefore,samples taken during summer w ere considered better in electricity production and w aste w ater treatment than those taken during w inter basically because of the high microbial load during the hot season.In parallel,there w as a decrease in both biological oxygen demand(BOD5)and chemical oxygen demand(COD)values which reached 71.8%and 72.85%,respectively at the end of the operation process for the summer sample,w hile there w as no evident decrease for the w inter sample.Optimizing the operating conditions not only increased the potential of using domestic w aste w ater in microbial fuel cells to produce electricity,but also improved the quality of the domestic w aste w ater.展开更多
Until relatively recently, little has been done of effective technique “zero effluent” to conserve energy and water. Tannery wastewater is known as complex characteristics. In this study batch electrocoagulation exp...Until relatively recently, little has been done of effective technique “zero effluent” to conserve energy and water. Tannery wastewater is known as complex characteristics. In this study batch electrocoagulation experiments were carried out to assess the removal of color and chemical oxygen demand (COD) from tannery wastewater using two types of electrode materials: aluminum and iron. The effects of current density, electrolysis time and initial pH were investigated for tannery wastewater. Therefore, the operating costs for each electrode have been calculated. Based on results, it can be concluded that iron is tremendous to aluminum as electrode material, from COD removal and energy consumption views. All the conclusions of the study revealed that treatment of tannery by EC can be applied as a step of a hybrid treatment.展开更多
Nitrogen removal is a critical process in water treatment plants(WIPs)and wastewater treatment plants(WWTPs).The recent discovery of a novel bacterial process,complete ammonia oxidation(comammox,CMX),has refuted a cen...Nitrogen removal is a critical process in water treatment plants(WIPs)and wastewater treatment plants(WWTPs).The recent discovery of a novel bacterial process,complete ammonia oxidation(comammox,CMX),has refuted a century-long perception of the two-step conversion of NH3to NO3-.Compared with canonical nitrifiers,CMX bacteria offer undeniable advantages,such as a high growth yield propensity and adaptability to nutrient-and growth-limiting conditions,which collectively draw attention to validate the aptness of CMX bacteria to wastewater treatment.As there has been no comprehensive review on the relevance of CMX bacteria for sustainable water and wastewater treatment,this review is intended to discuss the roles and applications of CMX in the removal of nitrogen and pollutants from water and wastewater.We took into account insights into the metabolic versatilities of CMX bacteria at the clade and subclade levels.We focused on the distribution of CMX bacteria in engineered systems,niche differentiation,co-occurrence and interactions with cano nical nitrifiers for a better understanding of CMX bacteria in terms of their ecophysiology.Conceptualized details on the reactor adaptability and stress response of CMX bacteria are provided.The potential of CMX bacteria to degrade micropollutants either directly or co-metabolically was evaluated,and these insights would be an indispensable advantage in opening the doors for wider applications of CMX bacteria in WWTPs.Finally,we summarized future directions of research that are imperative in improving the understanding of CMX biology.展开更多
Phase hybrid biological reactor (HBR) was used in treating coke wastewater by adding submerging fiber-ball fillers in suspended growth activated sludge.The optimum operation parameters for the highest performance were...Phase hybrid biological reactor (HBR) was used in treating coke wastewater by adding submerging fiber-ball fillers in suspended growth activated sludge.The optimum operation parameters for the highest performance were determined.It was found that the hybrid biological reactor worked well for the coke wastewater treatment in terms of Chemical Oxygen Demand (COD),NH+4-N and other refractory organic compounds removal efficiencies.Compared with conventional activated sludge system,the removal rate of COD and NH+4-N and the nitrating rate were higher and more stable in the hybrid biological reactor.COD of effluent was less than 75 mg/L and the removal rate of COD and NH+4-N could be up to 95.0% and 92.5% when COD of influent and NH+4-N were less than 700 mg/L and 300 mg/L,respectively.In this way,the quality of effluent concentration could reach the first class of integrated wastewater discharge standard (GB8978-1996)(COD ≤100 mg/L).展开更多
In this paper, we generalize H(.,.) accretive operator introduced by Zou and Huang [1] and we call it H(.,.)- φ - η - accretive operator. We define the resolvent operator associated with H(.,.)- φ - η - accretive ...In this paper, we generalize H(.,.) accretive operator introduced by Zou and Huang [1] and we call it H(.,.)- φ - η - accretive operator. We define the resolvent operator associated with H(.,.)- φ - η - accretive operator and prove its Lipschitz continuity. By using these concepts an iterative algorithm is suggested to solve a generalized variational-like inclusion problem. Some examples are given to justify the definition of H(.,.)- φ - η - accretive operator.展开更多
In the present paper, the semi-commutative differential oparators associated with the 1-dimensional Dirac operator are constructed. Using this results, the hierarchy of the mKdV (-) polynomials are expressed in terms ...In the present paper, the semi-commutative differential oparators associated with the 1-dimensional Dirac operator are constructed. Using this results, the hierarchy of the mKdV (-) polynomials are expressed in terms of the KdV polynomials. These formulas give a new interpretation of the classical Darboux transformation and the Miura transformation. Moreover, the recursion operator associated with the hierarchy of the mKdV (-) polynomials is constructed by the algebraic method.展开更多
This review focuses on techniques for achieving very low concentration of TN and TP in water.The 1970 Clean Water Act in the US and the Urban Waste Water Treatment Directive in Europe now provide the benchmark standar...This review focuses on techniques for achieving very low concentration of TN and TP in water.The 1970 Clean Water Act in the US and the Urban Waste Water Treatment Directive in Europe now provide the benchmark standards for TN and TP levels.Arden and Lockett discovered activated sludge in the 1910’s.Since then,many improvements have been made to the biological treatment process to provide various configurations that have the ability to deliver effluent concentrations between 6-8mg TN/L and 0.5-1.0mg TP/L,without external carbon addition.Typically,however,additional advanced nutrient removal technologies are used in tertiary treatment to meet more stringent effluent quality requirements.One advanced technology that has been successfully implemented in the US is denitrifying filters.For TP removal,tests showed that the BlueP RO and CoM ag systems both reliably met an effluent target as low as 0.04 mg TP/L.However,the establishment of stringent TN and TP effluent limits will dramatically increase the capital and operational costs of wastewater treatment plants.A more promising nutrient capturing process is based on the assimilation of nutrients(both N and P)during heterotrophic growth which uses a carbon source for energy.Laboratory trials of the single step process by Reach Green suggest that concentrations as low as 0.5 mg TN/L and 0.02mg TP/L are readily achievable.展开更多
This scientific paper is a comparative analysis of two mathematical conjectures. The newly proposed -3(-n) - 1 Remer conjecture and how it is related to and a proof of the more well known 3n + 1 Collatz conjecture. An...This scientific paper is a comparative analysis of two mathematical conjectures. The newly proposed -3(-n) - 1 Remer conjecture and how it is related to and a proof of the more well known 3n + 1 Collatz conjecture. An overview of both conjectures and their respective iterative processes will be presented. Showcasing their unique properties and behavior to each other. Through a detailed comparison, we highlight the similarities and differences between these two conjectures and discuss their significance in the field of mathematics. And how they prove each other to be true.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51108275)the Program for Liaoning Excellent Talents in Universities(LNET)(Grant No.LJQ2012101)+2 种基金the Program for New Century Excellent Talents in Universities(Grant No.NCET-11-1012)the Science and Technology Program of Liaoning Province(Grants No.2011229002 and2013229012)the Basic Science Research Fund in Northeastern University(Grants No.N130501001 and N140105003)
文摘In order to enhance the hydraulic loading rate (HLR) of a subsurface wastewater infiltration system (SWIS) used in treating domestic sewage, the intermittent operation mode was employed in the SWIS. The results show that the intermittent operation mode contributes to the improvement of the HLR and the pollutant removal rate. When the wetting-drying ratio (RwD) was 1.0, the pollutant removal rate increased by (13.6 ± 0.3)% for NH3-N, (20.7 ± 1.1)% for TN, (18.6± 0.4)% for TP, (12.2 ± 0.5)% for BOD, (10.1 ± 0.3)% for COD, and (36.2 ± 1.2)% for SS, compared with pollutant removal rates under the continuous operation mode. The pollutant removal rate declined with the increase of the HLR. The effluent quality met The Reuse of Urban Recycling Water - Water Quality Standard for Scenic Environment Use (GB/T 18921-2002) even when the HLR was as high as 10 cm/d. Hydraulic conductivity, oxidation reduction potential (ORP), the quantity of nitrifying bacteria, and the pollutant removal rate of NH3-N increased with the decrease of the RWD. For the pollutant removal rates of TP, BOD, and COD, there were no significant difference (p 〈 0.05) under different RwDS. The suggested RWD was 1.0. Relative contribution of the pretreatment and SWlS to the pollutant removal was examined, and more than 80% removal of NH3-N, TN, TP, COD, and BOD occurred in the SWIS.
基金supported by the Higher Education and High-quality and World-class Universities (PY201618)the National Natural Science Foundation of China (Contract Grant Number 51373014)the National Natural Science Foundation of China (Contract Grant Number 51403012)
文摘The pyromellitic dianhydride(PMDA) crosslinked poly(vinyl alcohol)(PVA) was coated on top of the PAN ultrafiltration membrane to form a PVA/PAN composite PV membranes for wastewater desalination. The composite membranes have high application value in industrial wastewater treatment. By varying the membrane fabrication parameters including the weight percent(wt%) of the PMDA, the crosslink temperature and duration, membrane with the best desalination performance was obtained. The composite membrane with a 2-lm-thick PVA selective layer containing 20 wt% of PMDA and being crosslinked at 100 °C for 2 h showed the highest Na Cl rejection of 99.98% with a water flux of 32.26 L/(m^2 h)at 70 °C using the 35,000 ppm Na Cl aqueous solution as feed. FTIR spectroscopy, wide-angle X-ray diffraction, thermogravimetric analysis and scanning electron microscope have been used to characterize the structures and properties of both the crosslinked PVA dense films and PVA/PAN composite membranes. The effects of the concentrations of PMDA,the crosslinking time and temperature to the membrane water contact angle, swelling degree, salt rejection and water flux were systematically studied.
基金supported by the National Natural Science Foundation of China(Nos.21975087,22008082)。
文摘Lithium metal batteries(LMBs) promise energy density over 400 Wh kg^(-1).However,they suffer severe electrochemical performance deterioration at sub-zero temperatures.Such failure behavior highly correlates to inferior lithium metal anode(LMA) compatibility and sluggish Li^(+) desolvation.Here,we demonstrate that cyclopentylmethyl ether(CPME) based diluted high-concentration electrolyte(DHCE)enables-60℃ LMBs operation.By leveraging the loose coordination between Li^(+) and CPME,such developed electrolyte boosts the formation of ion clusters to derive anion-dominant interfacial chemistry for enhancing LMA compatibility and greatly accelerates Li^(+) desolvation kinetics.The resulting electrolyte demonstrates high Coulombic efficiencies(CE),providing over 99.5%,99.1%,98.5% and 95% at 25,-20,-40,and-60℃respectively.The assembled Li-S battery exhibits remarkable cyclic stability in-20,and-40℃ at 0.2 C charging and 0.5 C discharging.Even at-60℃,Li-S cell with this designed electrolyte retains> 70% of the initial capacity over 170 cycles.Besides,lithium metal coin cell and pouch cell with10 mg cm^(-2) high S cathode loading exhibit cycling stability at-20℃.This work offers an opportunity for rational designing electrolytes toward low temperature LMBs.
文摘A new kind of bio-fluid bed used to treat dyes wastewater is described in detail due to its several special features,such as high removal efficiency,simple struc-ture,shock load resistance,etc.By means of analyzing the experiment data,the results show that the dye wastewater’s organic matter is removed greatly after be-ing treated by this new kind of bio-fluid bed.On the other hand,the removal efficiency of chromaticity of
基金supported by the National Natural Science Foundation of China(Grant No.51078074)the Key Project of the Chinese Ministry of Education(Grant No.308010)
文摘With rural population expansion and improvement of the socio-economic standard of living, treatment of rural domestic wastewater has rapidly become a major aspect of environmental concern. Selection of a suitable method for treatment of rural domestic wastewater depends on its efficiency, simplicity, and cost-effectiveness. This study investigated the effects of hydraulic retention time (HRT), temperature, and effluent recycling on the treatment efficiency of an anaerobic filter (AF) reactor. The first round of experimental operations was run for three months with HRTs of one, two, and three days, temperatures of 18℃, 21℃, and 24℃, and no effluent recycling. The second round of experimental operations was conducted for another three months with HRTs of three and four days; temperatures of 30.67℃, 30.57℃, and 26.91 ℃ ; and three effluent recycling ratios of 1:1, 1:2, and 2:1. The first round of operations showed removal rates of 32% to 44% for COD, 30% to 35% for TN, 32% to 36% for NH4-N, 19% to 23% for NO3-N, and 12% to 22% for TE In the second round of operations, the removal rates varied from 75% to 81% for COD, 35% to 41% for TN, 31% to 39% for NH4-N, 30% to 34% for NO3-N, and 41% to 48% for TP. The average gas production rates were 6.72 L/d and 7.26 L/d for the first and second rounds of operations, respectively. The gas production rate increased in the second round of operations as a result of applied effluent recycling. The best removal efficiency was obtained for an optimum HRT of three days, a temperature of 30℃, and an effluent recycling ratio of 2:1. The results show that the removal efficiency of the AF reactor was affected by HRT, temperature, and effluent recycling.
文摘Summary: The efficiency of cold storage red blood cells (CSRBC) or whole blood at -80 ℃ used in 27 Rh(D) negative patients during surgical operation was reported. The Rh(D) negative patients received the transfusion of CSRBC or whole blood stored at -80 ℃ for 180 to 360 days. The changes in the indexes, such as blood TB, DB, K +, Na +, BUN, Cr, urine protein (URPO), UOB, Hb, HCT, serum total protein, relative to hemolytic reaction and blood volume before and after transfusion were observed. The results showed that after transfusion of CSRBC or whole blood 27 cases were negative for urine protein and UOB, and the levels of BUN and Cr were normal (P>0.05). Blood TB, DB, Hb, and HCT were increased, while pH, blood K + and blood Na + was normal with the difference being not significant before and after operation (P>0.05). Plasma protein was decreased, but there was no significant difference before and after operation (P>0.05). It was suggested that CSRBC or whole blood at -80 ℃ could be safely infused to the Rh(D) negative patients without side effects during the surgical operation.
文摘Microbial fuel cells(M FCs)represent a new approach for treating w aste w ater along w ith electricity production.The present study addressed electricity production from domestic w astew ater using a mediator-less double chamber M FC.The electricity production w as monitored under different operational conditions for both summer and w inter samples.Optimization of the anodic and cathodic chambers resulted in a maximal current of 0.784 and 0.645 m A w ith the maximal pow er intensity of 209 and 117 m W/m2in pow er duration of 24 h for the summer and w inter samples,respectively.Scanning electron microscopy show ed that the bacterial biofilm formation on the anode w as denser for the summer sample than that w hen the w inter sample w as used,so w as the total bacterial count.Therefore,samples taken during summer w ere considered better in electricity production and w aste w ater treatment than those taken during w inter basically because of the high microbial load during the hot season.In parallel,there w as a decrease in both biological oxygen demand(BOD5)and chemical oxygen demand(COD)values which reached 71.8%and 72.85%,respectively at the end of the operation process for the summer sample,w hile there w as no evident decrease for the w inter sample.Optimizing the operating conditions not only increased the potential of using domestic w aste w ater in microbial fuel cells to produce electricity,but also improved the quality of the domestic w aste w ater.
文摘Until relatively recently, little has been done of effective technique “zero effluent” to conserve energy and water. Tannery wastewater is known as complex characteristics. In this study batch electrocoagulation experiments were carried out to assess the removal of color and chemical oxygen demand (COD) from tannery wastewater using two types of electrode materials: aluminum and iron. The effects of current density, electrolysis time and initial pH were investigated for tannery wastewater. Therefore, the operating costs for each electrode have been calculated. Based on results, it can be concluded that iron is tremendous to aluminum as electrode material, from COD removal and energy consumption views. All the conclusions of the study revealed that treatment of tannery by EC can be applied as a step of a hybrid treatment.
基金supported by the National Natural Science Foundation of China(52000185 and 51878675)Key Research and Development Program of Shandong Province(2019JZZY020308)China Postdoctoral Science Foundation,China(2017M612807)。
文摘Nitrogen removal is a critical process in water treatment plants(WIPs)and wastewater treatment plants(WWTPs).The recent discovery of a novel bacterial process,complete ammonia oxidation(comammox,CMX),has refuted a century-long perception of the two-step conversion of NH3to NO3-.Compared with canonical nitrifiers,CMX bacteria offer undeniable advantages,such as a high growth yield propensity and adaptability to nutrient-and growth-limiting conditions,which collectively draw attention to validate the aptness of CMX bacteria to wastewater treatment.As there has been no comprehensive review on the relevance of CMX bacteria for sustainable water and wastewater treatment,this review is intended to discuss the roles and applications of CMX in the removal of nitrogen and pollutants from water and wastewater.We took into account insights into the metabolic versatilities of CMX bacteria at the clade and subclade levels.We focused on the distribution of CMX bacteria in engineered systems,niche differentiation,co-occurrence and interactions with cano nical nitrifiers for a better understanding of CMX bacteria in terms of their ecophysiology.Conceptualized details on the reactor adaptability and stress response of CMX bacteria are provided.The potential of CMX bacteria to degrade micropollutants either directly or co-metabolically was evaluated,and these insights would be an indispensable advantage in opening the doors for wider applications of CMX bacteria in WWTPs.Finally,we summarized future directions of research that are imperative in improving the understanding of CMX biology.
文摘Phase hybrid biological reactor (HBR) was used in treating coke wastewater by adding submerging fiber-ball fillers in suspended growth activated sludge.The optimum operation parameters for the highest performance were determined.It was found that the hybrid biological reactor worked well for the coke wastewater treatment in terms of Chemical Oxygen Demand (COD),NH+4-N and other refractory organic compounds removal efficiencies.Compared with conventional activated sludge system,the removal rate of COD and NH+4-N and the nitrating rate were higher and more stable in the hybrid biological reactor.COD of effluent was less than 75 mg/L and the removal rate of COD and NH+4-N could be up to 95.0% and 92.5% when COD of influent and NH+4-N were less than 700 mg/L and 300 mg/L,respectively.In this way,the quality of effluent concentration could reach the first class of integrated wastewater discharge standard (GB8978-1996)(COD ≤100 mg/L).
文摘In this paper, we generalize H(.,.) accretive operator introduced by Zou and Huang [1] and we call it H(.,.)- φ - η - accretive operator. We define the resolvent operator associated with H(.,.)- φ - η - accretive operator and prove its Lipschitz continuity. By using these concepts an iterative algorithm is suggested to solve a generalized variational-like inclusion problem. Some examples are given to justify the definition of H(.,.)- φ - η - accretive operator.
基金supported by JSPS KAKENHI Grant Number 2354-0255.
文摘In the present paper, the semi-commutative differential oparators associated with the 1-dimensional Dirac operator are constructed. Using this results, the hierarchy of the mKdV (-) polynomials are expressed in terms of the KdV polynomials. These formulas give a new interpretation of the classical Darboux transformation and the Miura transformation. Moreover, the recursion operator associated with the hierarchy of the mKdV (-) polynomials is constructed by the algebraic method.
文摘This review focuses on techniques for achieving very low concentration of TN and TP in water.The 1970 Clean Water Act in the US and the Urban Waste Water Treatment Directive in Europe now provide the benchmark standards for TN and TP levels.Arden and Lockett discovered activated sludge in the 1910’s.Since then,many improvements have been made to the biological treatment process to provide various configurations that have the ability to deliver effluent concentrations between 6-8mg TN/L and 0.5-1.0mg TP/L,without external carbon addition.Typically,however,additional advanced nutrient removal technologies are used in tertiary treatment to meet more stringent effluent quality requirements.One advanced technology that has been successfully implemented in the US is denitrifying filters.For TP removal,tests showed that the BlueP RO and CoM ag systems both reliably met an effluent target as low as 0.04 mg TP/L.However,the establishment of stringent TN and TP effluent limits will dramatically increase the capital and operational costs of wastewater treatment plants.A more promising nutrient capturing process is based on the assimilation of nutrients(both N and P)during heterotrophic growth which uses a carbon source for energy.Laboratory trials of the single step process by Reach Green suggest that concentrations as low as 0.5 mg TN/L and 0.02mg TP/L are readily achievable.
文摘This scientific paper is a comparative analysis of two mathematical conjectures. The newly proposed -3(-n) - 1 Remer conjecture and how it is related to and a proof of the more well known 3n + 1 Collatz conjecture. An overview of both conjectures and their respective iterative processes will be presented. Showcasing their unique properties and behavior to each other. Through a detailed comparison, we highlight the similarities and differences between these two conjectures and discuss their significance in the field of mathematics. And how they prove each other to be true.