To rapidly determine the pollution extent of wastewater, the calibration models were established for deter-mination of Chemical Oxygen Demand and Biological Oxygen Demand in wastewater by partial least squares and nea...To rapidly determine the pollution extent of wastewater, the calibration models were established for deter-mination of Chemical Oxygen Demand and Biological Oxygen Demand in wastewater by partial least squares and near infrared spectrometry of 120 samples. Spectral data preprocessing and outliers’ diagnosis were also discussed. Correlation coefficients of the models were 0.9542 and 0.9652, and the root mean square error of prediction (RMSEP) were 25.24 mg?L-1 and 12.13 mg?L-1 in the predicted range of 28.40~528.0 mg?L-1 and 16.0~305.2 mg?L-1 for Chemical Oxygen Demand and Biological Oxygen Demand, respectively. By statistical significance test, the results of determination were compared with those of stan-dard methods with no significant difference at 0.05 level. The method has been applied to simultaneous de-termination of Chemical Oxygen Demand and Biological Oxygen Demand in wastewater with satisfactory results.展开更多
The removal of the natural organic matter present in coffee processing wastewater through chemical coagulation-flocculation and advanced oxidation processes （AOP） had been studied. The effectiveness of the removal o...The removal of the natural organic matter present in coffee processing wastewater through chemical coagulation-flocculation and advanced oxidation processes （AOP） had been studied. The effectiveness of the removal of natural organic matter using commercial flocculants and UV/H202, UV/O3 and UV/H2O2/O3 processes was determined under acidic conditions. For each of these processes, different operational conditions were explored to optimize the treatment efficiency of the coffee wastewater. Coffee wastewater is characterized by a high chemical oxygen demand （COD） and low total suspended solids. The outcomes of coffee wastewater treatment using coagulation-flocculation and photodegradation processes were assessed in terms of reduction of COD, color, and turbidity. It was found that a reduction in COD of 67% could be realized when the coffee wastewater was treated by chemical coagulation-flocculation with lime and coagulant T-1. When coffee wastewater was treated by coagulation-flocculation in combination with UV/H2O2, a COD reduction of 86% was achieved, although only after prolonged UV irradiation. Of the three advanced oxidation processes considered, UV/H2O2, UV/O3 and UV/H2O2/O3, we found that the treatment with UV/H2O2/O3 was the most effective, with an efficiency of color, turbidity and further COD removal of 87%, when applied to the flocculated coffee wastewater.展开更多
A three-dimensional advection-diffusion model coupled with the degradation process is established for describing the transport of chemical oxygen demand (COD). Comparison of the simulated distribution of COD at the su...A three-dimensional advection-diffusion model coupled with the degradation process is established for describing the transport of chemical oxygen demand (COD). Comparison of the simulated distribution of COD at the surface in the Bohai Sea in August, 2001 with field observations, shows that the model simulates the dataset reasonably well. The Laizhou Bay, Bohai Bay, and Liaodong Bay were contaminated heavily near shore. Based on the optimal discharge flux method, the Environmental Capacity (EC) and allocated capacities of COD in the Bohai Sea are calculated. For seawater of Grades I to IV of the Chinese National Standard, the ECs of COD in the Bohai Sea were 77×104 t/a, 116×104 t/a, 154×104 t/a and 193×104 t/a, respectively. The Huanghe (Yellow) River pollutant discharge accounted for the largest percentage of COD at 14.3%, followed by that of from the Liugu River (11.5%), and other nine local rivers below 10%. The COD level in 2005 was worse than that of Grade II seawater and was beyond the environmental capacity. In average, 35% COD reduction is called to meet the standard of Grade I seawater.展开更多
A field observation was carried out in the Changjiang (Yangtze) River Estuary from May 19 to 26, 2003. A total of 29 stations, including 2 anchored stations, were occupied through almost the whole salinity gradient. B...A field observation was carried out in the Changjiang (Yangtze) River Estuary from May 19 to 26, 2003. A total of 29 stations, including 2 anchored stations, were occupied through almost the whole salinity gradient. Based on the observation data, biogeochemistry of chemical oxygen demand (COD) was examined. Spatial distribution pattern of COD shows that it decreased downstream. The COD concentration varied generally within a narrow range of 1.24–1.60 mg/L in the zone around the river mouth, beyond which it decreased rapidly to 0.20 mg/L. In the mixed water zone, the fluctuation in COD was smaller at 2 m above the bottom layer than at the surface layer in 48 h. In the seawater zone, the 48-h fluctuation at the surface was the largest, followed by that of 5 m below the surface and 2 m above the bottom layers in a range of from 2.50 to 0.55 mg/L. Freshwater discharge was the dominant source of COD in the estuary. The average COD beyond the river mouth was 2.7 mg/L, which accorded with the Chinese seawater quality Grade I. Relationships between dissolved oxygen and biogeochemical parameters such as suspended particulate matter, dissolved organic matter and chlorophyll-a were also discussed.展开更多
Although near infrared (NIR) spectroscopy has been evaluated for numerous applications, the number of actual on-line or even on-site industrial applications seems to be very limited. In the present paper, the attempts...Although near infrared (NIR) spectroscopy has been evaluated for numerous applications, the number of actual on-line or even on-site industrial applications seems to be very limited. In the present paper, the attempts to produce online predictions of the chemical oxygen demand (COD) in wastewater from a pulp and paper mill using NIR spectroscopy are described. The task was perceived as very challenging, but with a root mean square error of prediction of 149 mg/l, roughly corresponding to 1/10 of the studied concentration interval, this attempt was deemed as successful. This result was obtained by using partial least squares model regression, interpolated reference values for calibration purposes, and by evenly distributing the calibration data in the concentration space. This work may also represent the first industrial application of online COD measurements in wastewater using NIR spectroscopy.展开更多
Nickel Graphite modified electrode (Ni/GME) was prepared by electrochemical method and degradation of Indigocarmine (IC) dye was carried out. An investigation between the efficiency of degradation by graphite electrod...Nickel Graphite modified electrode (Ni/GME) was prepared by electrochemical method and degradation of Indigocarmine (IC) dye was carried out. An investigation between the efficiency of degradation by graphite electrode and the Ni/graphite modified electrode has been carried out. The different effects of concentration, current density and temperature on the rate of degradation were studied. This study shows that the rate of the degradation is more for Ni doped modified graphite electrode. UV-Visible spectra before and after degradation of the dye solution were observed. The thin film formation of Ni or encapsulated in graphite rod is observed by scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM & EDAX). The instantaneous current effectiveness values of different experimental conditions are evaluated. The anodic oxidation by Ni/ graphite modified electrode showed the complete degradation of aqueous solution indigocarmine, which is confirmed by UV-Visible and chemical oxygen demand (COD) measurements. The dye is converted into CO2, H2O and simpler inorganic salts. The results observed for reuse of modified electrodes indicate that the Ni/graphite modified electrode would be a promising anode for electrochemical degradation of indigocarmine. This method can be applied for the remediation of waste water containing organics, cost-effective and simple.展开更多
文摘To rapidly determine the pollution extent of wastewater, the calibration models were established for deter-mination of Chemical Oxygen Demand and Biological Oxygen Demand in wastewater by partial least squares and near infrared spectrometry of 120 samples. Spectral data preprocessing and outliers’ diagnosis were also discussed. Correlation coefficients of the models were 0.9542 and 0.9652, and the root mean square error of prediction (RMSEP) were 25.24 mg?L-1 and 12.13 mg?L-1 in the predicted range of 28.40~528.0 mg?L-1 and 16.0~305.2 mg?L-1 for Chemical Oxygen Demand and Biological Oxygen Demand, respectively. By statistical significance test, the results of determination were compared with those of stan-dard methods with no significant difference at 0.05 level. The method has been applied to simultaneous de-termination of Chemical Oxygen Demand and Biological Oxygen Demand in wastewater with satisfactory results.
文摘The removal of the natural organic matter present in coffee processing wastewater through chemical coagulation-flocculation and advanced oxidation processes （AOP） had been studied. The effectiveness of the removal of natural organic matter using commercial flocculants and UV/H202, UV/O3 and UV/H2O2/O3 processes was determined under acidic conditions. For each of these processes, different operational conditions were explored to optimize the treatment efficiency of the coffee wastewater. Coffee wastewater is characterized by a high chemical oxygen demand （COD） and low total suspended solids. The outcomes of coffee wastewater treatment using coagulation-flocculation and photodegradation processes were assessed in terms of reduction of COD, color, and turbidity. It was found that a reduction in COD of 67% could be realized when the coffee wastewater was treated by chemical coagulation-flocculation with lime and coagulant T-1. When coffee wastewater was treated by coagulation-flocculation in combination with UV/H2O2, a COD reduction of 86% was achieved, although only after prolonged UV irradiation. Of the three advanced oxidation processes considered, UV/H2O2, UV/O3 and UV/H2O2/O3, we found that the treatment with UV/H2O2/O3 was the most effective, with an efficiency of color, turbidity and further COD removal of 87%, when applied to the flocculated coffee wastewater.
基金Supported by 908 Program of the State Ocean Administration of China (Nos.908-02-02-02,908-02-02-03)the State Ocean Administration Foundation of China (No.200805065)
文摘A three-dimensional advection-diffusion model coupled with the degradation process is established for describing the transport of chemical oxygen demand (COD). Comparison of the simulated distribution of COD at the surface in the Bohai Sea in August, 2001 with field observations, shows that the model simulates the dataset reasonably well. The Laizhou Bay, Bohai Bay, and Liaodong Bay were contaminated heavily near shore. Based on the optimal discharge flux method, the Environmental Capacity (EC) and allocated capacities of COD in the Bohai Sea are calculated. For seawater of Grades I to IV of the Chinese National Standard, the ECs of COD in the Bohai Sea were 77×104 t/a, 116×104 t/a, 154×104 t/a and 193×104 t/a, respectively. The Huanghe (Yellow) River pollutant discharge accounted for the largest percentage of COD at 14.3%, followed by that of from the Liugu River (11.5%), and other nine local rivers below 10%. The COD level in 2005 was worse than that of Grade II seawater and was beyond the environmental capacity. In average, 35% COD reduction is called to meet the standard of Grade I seawater.
基金Supported by National Basic Research Program of China 973 plan (2007CB407305)the Qingdao Special Program for Leading Scientists (05-2-JC-90)the "100 Talents Project" of the Chinese Academy of Sciences
文摘A field observation was carried out in the Changjiang (Yangtze) River Estuary from May 19 to 26, 2003. A total of 29 stations, including 2 anchored stations, were occupied through almost the whole salinity gradient. Based on the observation data, biogeochemistry of chemical oxygen demand (COD) was examined. Spatial distribution pattern of COD shows that it decreased downstream. The COD concentration varied generally within a narrow range of 1.24–1.60 mg/L in the zone around the river mouth, beyond which it decreased rapidly to 0.20 mg/L. In the mixed water zone, the fluctuation in COD was smaller at 2 m above the bottom layer than at the surface layer in 48 h. In the seawater zone, the 48-h fluctuation at the surface was the largest, followed by that of 5 m below the surface and 2 m above the bottom layers in a range of from 2.50 to 0.55 mg/L. Freshwater discharge was the dominant source of COD in the estuary. The average COD beyond the river mouth was 2.7 mg/L, which accorded with the Chinese seawater quality Grade I. Relationships between dissolved oxygen and biogeochemical parameters such as suspended particulate matter, dissolved organic matter and chlorophyll-a were also discussed.
文摘Although near infrared (NIR) spectroscopy has been evaluated for numerous applications, the number of actual on-line or even on-site industrial applications seems to be very limited. In the present paper, the attempts to produce online predictions of the chemical oxygen demand (COD) in wastewater from a pulp and paper mill using NIR spectroscopy are described. The task was perceived as very challenging, but with a root mean square error of prediction of 149 mg/l, roughly corresponding to 1/10 of the studied concentration interval, this attempt was deemed as successful. This result was obtained by using partial least squares model regression, interpolated reference values for calibration purposes, and by evenly distributing the calibration data in the concentration space. This work may also represent the first industrial application of online COD measurements in wastewater using NIR spectroscopy.
文摘Nickel Graphite modified electrode (Ni/GME) was prepared by electrochemical method and degradation of Indigocarmine (IC) dye was carried out. An investigation between the efficiency of degradation by graphite electrode and the Ni/graphite modified electrode has been carried out. The different effects of concentration, current density and temperature on the rate of degradation were studied. This study shows that the rate of the degradation is more for Ni doped modified graphite electrode. UV-Visible spectra before and after degradation of the dye solution were observed. The thin film formation of Ni or encapsulated in graphite rod is observed by scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM & EDAX). The instantaneous current effectiveness values of different experimental conditions are evaluated. The anodic oxidation by Ni/ graphite modified electrode showed the complete degradation of aqueous solution indigocarmine, which is confirmed by UV-Visible and chemical oxygen demand (COD) measurements. The dye is converted into CO2, H2O and simpler inorganic salts. The results observed for reuse of modified electrodes indicate that the Ni/graphite modified electrode would be a promising anode for electrochemical degradation of indigocarmine. This method can be applied for the remediation of waste water containing organics, cost-effective and simple.
