In this study two types of biological contact oxidation processes(BCOP),a step-feed(SBCOP)unit and an inter-recycle(IBCOP)unit,were designed to investigate the treatment of heavily polluted river water.The Daqing Rive...In this study two types of biological contact oxidation processes(BCOP),a step-feed(SBCOP)unit and an inter-recycle(IBCOP)unit,were designed to investigate the treatment of heavily polluted river water.The Daqing River,which is the largest pollutant contributor to the Dianchi Lake,one of the most eutrophic freshwater lakes in China,was taken for the case study.It was found that the SBCOP had higher adaptability and better performance in the reduction of COD,TN,and TP,which made it applicable for the treatment of polluted river water entering the Dianchi Lake.Nitrification rate was observed to be greatly affected by the influent temperature.During each season,the nitrification in the SBCOP was higher than that in the IBCOP.TN removal efficiency in the SBCOP was higher than that in the IBCOP during the winter and spring but poorer during the summer,possibly due to the inhibition of denitrification by higher dissolved oxygen level in the summer.Moreover,symbiotic algaebacteria growth may be conducive to the removal of pollutants.展开更多
This research focuses on the evaluation of diverse approaches for removing formaldehyde from indoor environments,which is a significant concern for indoor air quality.The study systematically examines physical,chemica...This research focuses on the evaluation of diverse approaches for removing formaldehyde from indoor environments,which is a significant concern for indoor air quality.The study systematically examines physical,chemical,and biological methods to ascertain their effectiveness in formaldehyde mitigation.Physical methods,including air circulation and adsorption,particularly with activated carbon and molecular sieves,are assessed for their efficiency in various concentration scenarios.Chemical methods,such as photocatalytic oxidation using titanium dioxide and plasma technology,are analyzed for their ability to decompose formaldehyde into non-toxic substances.Additionally,biological methods involving plant purification and microbial transformation are explored for their eco-friendly and sustainable removal capabilities.The paper concludes that while each method has its merits,a combined approach may offer the most effective solution for reducing indoor formaldehyde levels.The study underscores the need for further research to integrate these methods in a practical,cost-effective,and environmentally sustainable manner,highlighting their potential to improve indoor air quality significantly.展开更多
The coan cbargr transfer (CCT) absorption spectra of isopropyl ether , phenyl isopropyl ether and benzyl isopropyl ether with oxygen were measured . The mechanism of the initial dark oxidation of different ethers via ...The coan cbargr transfer (CCT) absorption spectra of isopropyl ether , phenyl isopropyl ether and benzyl isopropyl ether with oxygen were measured . The mechanism of the initial dark oxidation of different ethers via ether-O2 CCT was展开更多
Compared to conventional oxidation ditches, an integrated oxidation ditch with vertical circle（IODVC） has the characters of concise configuration, simple operation and maintenance, land saving and automatical sludge...Compared to conventional oxidation ditches, an integrated oxidation ditch with vertical circle（IODVC） has the characters of concise configuration, simple operation and maintenance, land saving and automatical sludge returning. By the utilization of vertical circulation, an aerobic zone and an anoxic zone can be unaffectedly formed in the IODVC. Therefore, COD and nitrogen can be efficiently removed. However, the removal efficiency of phosphorus was low in the IODVC. In the experiment described, a laboratory scale system to add an anaerobic column to the IODVC has been tested to investigate the removal of phosphorus from wastewater. The experimental results showed that the removal efficiency of TP with the anaerobic column was increased to 54.0% from 22.3% without the anaerobic column. After the acetic sodium was added into the influent as carbon sources, the mean TP removal efficency of 77.5% was obtained. At the same time, the mean removal efficiencies of COD, TN and NH3-N were 92.2%, 81.6% and 98.1%, respectively, at 12 h of HRT and 21—25 d of SRT. The optimal operational conditions in this study were as follows: recycle rate1.5—2.0, COD/TN>6, COD/TP>40, COD loading rate0.26—0.32 kgCOD/（kgSS·d）, TN loading rate0.028—0.034 kgTN/（kgSS·d） and TP loading rate0.003—0.005 kgTP/（kgSS·d）, respectively.展开更多
The superior drainage was pre-treated by biologic contact oxidation on BOD5 load of 0.72 kg/(m3·d),and then post-treated by constructed wetland. The results about the effect on the constructed wetland post-treatm...The superior drainage was pre-treated by biologic contact oxidation on BOD5 load of 0.72 kg/(m3·d),and then post-treated by constructed wetland. The results about the effect on the constructed wetland post-treatment show that the total nitrogen (TN) is the restrictive index of the combinational technique treatment effect. To meet the reclaimed water quality standard and reuse for waterscape,the peak hydraulic load of constructed wetland is 0.50 m/d in summer (30-36 ℃) and 0.33 m/d in winter (8-12℃),and the load ratio of the peak hydraulic under the two temperature conditions is 3-2. The results are combined of reclaimed water quantity requirements in different seasons of green building. Reasonable scale of the reclaimed water treatment systems can be determined. The treatment efficacy can be well predicted,and both the design and operations can be effectively guided,by which the reclaimed water treatment systems regard superior drainage as the source and are purified by combinational technique of contact oxidation and artificial wetland.展开更多
The gasification wastewater is a kind of typical organic industrial wastewater with high chemical oxygen demand (COD) and ammonia nitrogen, which could not be completely degraded by the traditional physical, chemical ...The gasification wastewater is a kind of typical organic industrial wastewater with high chemical oxygen demand (COD) and ammonia nitrogen, which could not be completely degraded by the traditional physical, chemical and biological method. So it is very important to find an effective treatment process. A combination process of catalytic oxidation with noble metal catalysts and aerobic biological fluid-bed packed with the new ultrastructure biological carriers, which was developed by ourselves, was investigated to treat the gasification wastewater. The pilot scale test with 0.5 m3/h influent flow was carried out to investigate the performance of this new combination process. The results showed that the effluent COD was 84.02 mg/L, ammonia nitrogen was 14.15 mg/L, and total phenol was 0.20 mg/L, which could completely meet the Grade Ⅰof Wastewater Discharge Standard (GB8978-1996), when the influent average COD was 5564 mg/L, ammonia nitrogen was 237 mg/L, and total phenol was 1100 mg/L. The two catalytic reactors could evidently improve the wastewater biodegradability, and the value of BOD5/COD (B/C) increased from 0.23 to 0.413 in the one-stage catalytic reactor and from 0.273 to 0.421 in two-stage catalytic reactor. The further experiment results showed that the effluent quality of this new combination process could still meet the discharge standard, when the COD loading was 8.65 kg / (m3·d). Most of aromatic and heterocyclic compounds were degraded effectively in this combination process.展开更多
Catalytic wet air oxidation(CWAO) can degrade some refractory pollutants at a low cost to improve the biodegradability of wastewater. However, in the presence of high temperature and high pressure and strong oxidizing...Catalytic wet air oxidation(CWAO) can degrade some refractory pollutants at a low cost to improve the biodegradability of wastewater. However, in the presence of high temperature and high pressure and strong oxidizing free radicals, the stability of catalysts is often insufficient, which has become a bottleneck in the application of CWAO. In this paper, a copper-based catalyst with excellent hydrothermal stability was designed and prepared. TiO_(2) with excellent stability was used as the carrier to ensure the longterm anchoring of copper and reduce the leaching of the catalyst. The one pot sol–gel method was used to ensure the super dispersion and uniform distribution of copper nanoparticles on the carrier, so as to ensure that more active centers could be retained in a longer period. Experiments show that the catalyst prepared by this method has good stability and catalytic activity, and the catalytic effect is not significantly reduced after 10 cycles of use. The oxidation degradation experiment of m-cresol with the strongest biological toxicity and the most difficult to degrade in coal chemical wastewater was carried out with this catalyst. The results showed that under the conditions of 140℃, 2 MPa and 2 h, m-cresol with a concentration of up to 1000 mg·L^(-1) could be completely degraded, and the COD removal rate could reach 79.15%. The biological toxicity of wastewater was significantly reduced. The development of the catalyst system has greatly improved the feasibility of CWAO in the treatment of refractory wastewater such as coal chemical wastewater.展开更多
Effects of hydraulic retention time (HRT ) and gas volume on efficiency of wastewater treatment are dis- cussed based on a simulation experiment in which the domestic swage was treated by the two-stage-bio-contact oxi...Effects of hydraulic retention time (HRT ) and gas volume on efficiency of wastewater treatment are dis- cussed based on a simulation experiment in which the domestic swage was treated by the two-stage-bio-contact oxida- tion process. The result shows that the average CODCr, BOD5 , suspended solid (SS), and ammonia-nitrogen removal rate are 94.5 %, 93.2 %, 91.7 % and 46.9 %, respectively, under the conditions of a total air/water ratio of 5∶1 , an air/water ratio of 3:1 for oxidation tank 1 and 2:1for oxidation tank 2and a hydraulic retention time of 1 h for each stage. This method is suitable for domestic sewage treatment of residential community and small towns as well.展开更多
Nano-TiO_2 photocatalytic oxidation was used to perform the advanced treatment of biologically treated chemical comprehensive wastewater. The effects of reaction time,nano-TiO_2 dosage and initial p H of the wastewate...Nano-TiO_2 photocatalytic oxidation was used to perform the advanced treatment of biologically treated chemical comprehensive wastewater. The effects of reaction time,nano-TiO_2 dosage and initial p H of the wastewater on the removal rate of COD were tested. The GC/MS and EEM techniques were used to qualitatively analyze organic compounds in the wastewater before and after treatment. The result showed that after the biologically treated chemical comprehensive wastewater was treated by nano-TiO_2 photocatalytic oxidation under the conditions of reaction time 3 h,nano-TiO_2 dosage 8 g/L,and pH 8. 0,the effluent COD was 61. 9 mg/L and its removal rate was 63. 8%. Additionally,the species of organic pollutants reduced from 12 to 6. Meanwhile,the content of humic-like and fulvic-like substances dropped dramatically.展开更多
基金This study was supported by the National High Technology Research and Development Program of China(863 Program)(Grant No.2005AA601010-03)the National Natural Science Foundation of China(Grant No.50778001).
文摘In this study two types of biological contact oxidation processes(BCOP),a step-feed(SBCOP)unit and an inter-recycle(IBCOP)unit,were designed to investigate the treatment of heavily polluted river water.The Daqing River,which is the largest pollutant contributor to the Dianchi Lake,one of the most eutrophic freshwater lakes in China,was taken for the case study.It was found that the SBCOP had higher adaptability and better performance in the reduction of COD,TN,and TP,which made it applicable for the treatment of polluted river water entering the Dianchi Lake.Nitrification rate was observed to be greatly affected by the influent temperature.During each season,the nitrification in the SBCOP was higher than that in the IBCOP.TN removal efficiency in the SBCOP was higher than that in the IBCOP during the winter and spring but poorer during the summer,possibly due to the inhibition of denitrification by higher dissolved oxygen level in the summer.Moreover,symbiotic algaebacteria growth may be conducive to the removal of pollutants.
文摘This research focuses on the evaluation of diverse approaches for removing formaldehyde from indoor environments,which is a significant concern for indoor air quality.The study systematically examines physical,chemical,and biological methods to ascertain their effectiveness in formaldehyde mitigation.Physical methods,including air circulation and adsorption,particularly with activated carbon and molecular sieves,are assessed for their efficiency in various concentration scenarios.Chemical methods,such as photocatalytic oxidation using titanium dioxide and plasma technology,are analyzed for their ability to decompose formaldehyde into non-toxic substances.Additionally,biological methods involving plant purification and microbial transformation are explored for their eco-friendly and sustainable removal capabilities.The paper concludes that while each method has its merits,a combined approach may offer the most effective solution for reducing indoor formaldehyde levels.The study underscores the need for further research to integrate these methods in a practical,cost-effective,and environmentally sustainable manner,highlighting their potential to improve indoor air quality significantly.
文摘The coan cbargr transfer (CCT) absorption spectra of isopropyl ether , phenyl isopropyl ether and benzyl isopropyl ether with oxygen were measured . The mechanism of the initial dark oxidation of different ethers via ether-O2 CCT was
文摘Compared to conventional oxidation ditches, an integrated oxidation ditch with vertical circle（IODVC） has the characters of concise configuration, simple operation and maintenance, land saving and automatical sludge returning. By the utilization of vertical circulation, an aerobic zone and an anoxic zone can be unaffectedly formed in the IODVC. Therefore, COD and nitrogen can be efficiently removed. However, the removal efficiency of phosphorus was low in the IODVC. In the experiment described, a laboratory scale system to add an anaerobic column to the IODVC has been tested to investigate the removal of phosphorus from wastewater. The experimental results showed that the removal efficiency of TP with the anaerobic column was increased to 54.0% from 22.3% without the anaerobic column. After the acetic sodium was added into the influent as carbon sources, the mean TP removal efficency of 77.5% was obtained. At the same time, the mean removal efficiencies of COD, TN and NH3-N were 92.2%, 81.6% and 98.1%, respectively, at 12 h of HRT and 21—25 d of SRT. The optimal operational conditions in this study were as follows: recycle rate1.5—2.0, COD/TN>6, COD/TP>40, COD loading rate0.26—0.32 kgCOD/（kgSS·d）, TN loading rate0.028—0.034 kgTN/（kgSS·d） and TP loading rate0.003—0.005 kgTP/（kgSS·d）, respectively.
基金Project(SWITCH018530) supported by the EU Sixth Framework Program-Sustainable Water management Improves Tomorrow’s CitiesProject(2008DFA91770) supported by the International Cooperation Items of the Ministry of Science and Technology,China
文摘The superior drainage was pre-treated by biologic contact oxidation on BOD5 load of 0.72 kg/(m3·d),and then post-treated by constructed wetland. The results about the effect on the constructed wetland post-treatment show that the total nitrogen (TN) is the restrictive index of the combinational technique treatment effect. To meet the reclaimed water quality standard and reuse for waterscape,the peak hydraulic load of constructed wetland is 0.50 m/d in summer (30-36 ℃) and 0.33 m/d in winter (8-12℃),and the load ratio of the peak hydraulic under the two temperature conditions is 3-2. The results are combined of reclaimed water quantity requirements in different seasons of green building. Reasonable scale of the reclaimed water treatment systems can be determined. The treatment efficacy can be well predicted,and both the design and operations can be effectively guided,by which the reclaimed water treatment systems regard superior drainage as the source and are purified by combinational technique of contact oxidation and artificial wetland.
基金the Key Project in Science and Technology of Heilongjiang Province , China (No. GB06C20401)
文摘The gasification wastewater is a kind of typical organic industrial wastewater with high chemical oxygen demand (COD) and ammonia nitrogen, which could not be completely degraded by the traditional physical, chemical and biological method. So it is very important to find an effective treatment process. A combination process of catalytic oxidation with noble metal catalysts and aerobic biological fluid-bed packed with the new ultrastructure biological carriers, which was developed by ourselves, was investigated to treat the gasification wastewater. The pilot scale test with 0.5 m3/h influent flow was carried out to investigate the performance of this new combination process. The results showed that the effluent COD was 84.02 mg/L, ammonia nitrogen was 14.15 mg/L, and total phenol was 0.20 mg/L, which could completely meet the Grade Ⅰof Wastewater Discharge Standard (GB8978-1996), when the influent average COD was 5564 mg/L, ammonia nitrogen was 237 mg/L, and total phenol was 1100 mg/L. The two catalytic reactors could evidently improve the wastewater biodegradability, and the value of BOD5/COD (B/C) increased from 0.23 to 0.413 in the one-stage catalytic reactor and from 0.273 to 0.421 in two-stage catalytic reactor. The further experiment results showed that the effluent quality of this new combination process could still meet the discharge standard, when the COD loading was 8.65 kg / (m3·d). Most of aromatic and heterocyclic compounds were degraded effectively in this combination process.
基金support provided by the National Natural Science Foundation of China (21978143 and 21878164)。
文摘Catalytic wet air oxidation(CWAO) can degrade some refractory pollutants at a low cost to improve the biodegradability of wastewater. However, in the presence of high temperature and high pressure and strong oxidizing free radicals, the stability of catalysts is often insufficient, which has become a bottleneck in the application of CWAO. In this paper, a copper-based catalyst with excellent hydrothermal stability was designed and prepared. TiO_(2) with excellent stability was used as the carrier to ensure the longterm anchoring of copper and reduce the leaching of the catalyst. The one pot sol–gel method was used to ensure the super dispersion and uniform distribution of copper nanoparticles on the carrier, so as to ensure that more active centers could be retained in a longer period. Experiments show that the catalyst prepared by this method has good stability and catalytic activity, and the catalytic effect is not significantly reduced after 10 cycles of use. The oxidation degradation experiment of m-cresol with the strongest biological toxicity and the most difficult to degrade in coal chemical wastewater was carried out with this catalyst. The results showed that under the conditions of 140℃, 2 MPa and 2 h, m-cresol with a concentration of up to 1000 mg·L^(-1) could be completely degraded, and the COD removal rate could reach 79.15%. The biological toxicity of wastewater was significantly reduced. The development of the catalyst system has greatly improved the feasibility of CWAO in the treatment of refractory wastewater such as coal chemical wastewater.
文摘Effects of hydraulic retention time (HRT ) and gas volume on efficiency of wastewater treatment are dis- cussed based on a simulation experiment in which the domestic swage was treated by the two-stage-bio-contact oxida- tion process. The result shows that the average CODCr, BOD5 , suspended solid (SS), and ammonia-nitrogen removal rate are 94.5 %, 93.2 %, 91.7 % and 46.9 %, respectively, under the conditions of a total air/water ratio of 5∶1 , an air/water ratio of 3:1 for oxidation tank 1 and 2:1for oxidation tank 2and a hydraulic retention time of 1 h for each stage. This method is suitable for domestic sewage treatment of residential community and small towns as well.
文摘Nano-TiO_2 photocatalytic oxidation was used to perform the advanced treatment of biologically treated chemical comprehensive wastewater. The effects of reaction time,nano-TiO_2 dosage and initial p H of the wastewater on the removal rate of COD were tested. The GC/MS and EEM techniques were used to qualitatively analyze organic compounds in the wastewater before and after treatment. The result showed that after the biologically treated chemical comprehensive wastewater was treated by nano-TiO_2 photocatalytic oxidation under the conditions of reaction time 3 h,nano-TiO_2 dosage 8 g/L,and pH 8. 0,the effluent COD was 61. 9 mg/L and its removal rate was 63. 8%. Additionally,the species of organic pollutants reduced from 12 to 6. Meanwhile,the content of humic-like and fulvic-like substances dropped dramatically.
